ICG Coencapsulated Liposome-Coated Thermosensitive

Article Cite This: ACS Biomater. Sci. Eng. 2018, 4, 2424−2434

DOX/ICG Coencapsulated Liposome-Coated Thermosensitive Nanogels for NIR-Triggered Simultaneous Drug Release and Photothermal Effect Lixia Yu,† Anjie Dong,†,‡ Ruiwei Guo,† Muyang Yang,† Liandong Deng,† and Jianhua Zhang*,†,§ †

ACS Biomater. Sci. Eng. 2018.4:2424-2434. Downloaded from pubs.acs.org by UNIV OF SUSSEX on 08/17/18. For personal use only.

Department of Polymer Science and Engineering, Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China ‡ Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China § Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072, China S Supporting Information *

ABSTRACT: Chemo-photothermal therapy has shown enormous potential in treating cancer. To achieve the chemophotothermal synergistic effect, an efficient nanoparticulate system with the ability for simultaneous codelivery of chemotherapeutic drug and photothermal agent as well as photothermal-triggered drug release is highly desirable. Herein, an in situ polymerization within liposome template was designed to prepare liposome-coated poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAM-co-AAM)) nanogels, which can efficiently coencapsulate a NIR dye indocyanine green (ICG) and high amount of doxorubicin hydrochloride (DOX). The DOX/ICG coloaded hybrid nanogels, denoted as DI-NGs@lipo, integrated the desirable functions of PEGylated liposomes and thermosensitive nanogels. The PEGylated liposome shell provided excellent storage stability, hemodynamic stability, and fluorescence stability. Meanwhile, the thermosensitive P(NIPAM-co-AAM) nanogels core endowed DI-NGs@lipo with volume phase transition temperature (VPTT) at about 40 °C, allowing for thermo-controlled transformation and drug release. The significant photothermal effect of DI-NGs@lipo and the simultaneous hyperthermia-triggered DOX release were observed under NIR light irradiation. The DI-NGs@lipo was demonstrated to be uptaken by 4T1 murine breast cancer cells via endocytosis, enhancing the distribution of DOX in the cell nucleus. Compared with chemo or photothermal treatment alone, the combination treatment of DI-NGs@lipo with NIR light irradiation induced significantly higher cytotoxicity to 4T1 cells, demonstrating the chemo-photothermal synergistic therapeutic effects on tumor cells. In a word, the strategy provided here offers a facile approach to develop a multifunctional nanoplatform for codelivery of DOX and ICG, which can synergistically improve the cancer-cellkilling efficiency, demonstrating great potential in chemo-photothermal therapy. KEYWORDS: liposomes, template polymerization, temperature-sensitive nanogels, active loading, photothermal effect

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INTRODUCTION Cancer has presently become one of the deadliest diseases around the world. Among cancer therapeutics, chemotherapy has been widely applied. However, it usually confronts some limits, especially with respect to the nonspecific distribution and thus severe systemic toxicity.1,2 Nanoparticulate drugdelivery systems open a new avenue toward the diagnosis and treatment of a variety of cancers.3−6 In particular, the environmentally sensitive nanocarriers that can trigger drug release at the tumor site in response to endogenous stimuli (e.g., pH, redox, and enzyme) or exogenous stimuli (e.g., temperature, light, magnetic field, ultrasound intensity, or electric pulses) have been developed to enable tumor-specific release and thus improve chemotherapeutic efficacy.7−11 However, because of the uncontrollable specific microenvironments and individual differences in the human body, the © 2018 American Chemical Society

accurate control and release of drugs triggered by endogenous stimuli often achieve limited efficiency.8 Therefore, the exogenous stimuli-responsive drug-delivery systems might be more favorable for tunable and specific anticancer drug delivery.8,11 Owing to its noninvasiveness, high biocompatibility, ease of application reversible, and the remote spatiotemporal control, utilization of light as an external stimulus to trigger drug release or induce local hyperthermia has generated considerable interest. The near-infrared (NIR) light with wavelengths in the range of about 700 to 900 nm has been considered to be the most promising optical stimulus because of its minimal Received: March 29, 2018 Accepted: May 11, 2018 Published: May 11, 2018 2424

DOI: 10.1021/acsbiomaterials.8b00379 ACS Biomater. Sci. Eng. 2018, 4, 2424−2434

Article

ACS Biomaterials Science & Engineering

Scheme 1. Schematic Illustration of DI-NGs@lipo Prepared by In Situ Polymerization within Liposome Template (A) and NIR Irradiation-Induced Hyperthermia Triggered Intracellular DOX Release for Synergistic Chemo-Photothermal Therapy (B)

such as pH, redox, temperature, are one of the most promising nanoparticulate platforms in the area of drug delivery.7,25−27 Thermosensitive nanogels based on poly(N-isopropylacrylamide) (PNIPAM) that can change their particle volume in response to the environmental temperature have been widely used as thermosensitive drug-delivery systems.28−30 More importantly, the VPTT of PNIPAM, generally at around 32 °C, can be simply tuned by controlling the hydrophilic/hydrophobic balance of the polymer via copolymerization of another hydrophilic monomer.31−33 For example, the introduction of good hydrophilic acrylamide (AAM) component could increase the VPTT of PNIPAM, which may be suitable for the application of photothermal-induced drug release.29 By now, a variety of PNIPAM-based nanogels have been reported and successfully used to improve drug-delivery efficacy.28,34−36 However, only very few studies have employed PNIPAM-based nanogels in the field of photothermal-induced drug release, because their pharmaceutical applications still suffer from extremely low drug loading, relatively rapid drug release and thus high premature leakage, low batch-to-batch reproducibility, and difficulty in scalable morphology-controlled fabrication.8,24,37,38 Recently, the liposome-coated nanogels, featuring an inner polymeric hydrogels core and an outer liposomes shell, integrate the desirable features of both nanogels and liposomes in a single nanocarrier.39−44 The cross-linked hydrogel cores can not only markedly improve the mechanical stability but also bring new functionality (e.g., rapid stimuli-responsiveness) to the liposomal formulations. Meanwhile, the liposomal shell can not only improve the biocompatibility and hemodynamic stability of nanogels but also decrease premature drug leakage from nanogels.39,40,45 Apparently, these beneficial features make

attenuation and deep tissue penetration as well as less damage to tissues. Especially, the photothermal therapy (PTT) based on photosensitizers, such as indocyanine green (ICG), that strongly absorb NIR light to generate heat for tumor treatment, has been demonstrated as a highly efficient therapeutic technique and exhibited several unique advantages in cancer therapy, such as minimal invasiveness, high specificity, and precise spatiotemporal selectivity.12−14 More importantly, hyperthermia induced by NIR light not only can directly cause thermal ablation of cancer cells and increase the sensitivity of tumor cells to chemotherapy drugs but also can improve the permeability of tumor vessels because of the enhancement of blood flow in the hyperthermia area.15−17 Therefore, the photothermal therapies based on NIR-induced hyperthermia have been widely combined with chemotherapy to enhance the anticancer efficacy.15,18 Especially, the integration of photothermal therapy and chemotherapy into a single nanoplatform has shown therapeutic efficiencies superior to those achieved by a single treatment.15,19−22 However, to achieve the synergistic effects of chemo-photothermal combination therapy, it is expected that the high doses of chemotherapy drug and photosensitizer can be simultaneously delivered to the same tumor cells and exert chemo-photothermal therapeutic functions in a synergistic manner. Apparently, the synergistic codelivery of chemotherapeutic agent and photosensitizer will necessarily require further development of multifunctional nanocarriers with the ability of efficient encapsulation, hemodynamic stability and NIR-triggered drug release by the photothermal-induced nanostructural transition.14,23 With the development of nanocarriers, versatile nanogels have attracted great attentions.19,24 In particular, stimuliresponsive nanogels that can respond to environmental stimuli, 2425


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size of about 100 nm composed of egg PC, cholesterol, and DSPEPEG of 75:13:12 in a mass ratio were prepared by the hydration method. Briefly, a mixture (about 56 mg) of egg PC, cholesterol, and DSPE-PEG was dissolved in chloroform and transferred to a roundbottom flask. Additionally, the lipid film was formed after evaporating the solvents with a rotary evaporator at 80 rpm in a 35 °C water bath. The resulting lipid thin film was further dried overnight under vacuum to remove the residual solvent. To prepare drug-free liposome-coated nanogels (NGs@lipo), an in situ polymerization within liposome template was designed by using hydrogel precursor solution. Briefly, the resulting dried lipid film was rehydrated by sonication in an ice−water bath using 5 mL of hydrogel precursor solution including the calculated amount of NIPAM, AAM, V-50, and MBA with the corresponding feeding molar ratio of 89.2:9.6:0.4:0.8 at the monomer concentration of about 4.5 wt %. In order to acquire nanoscale and homogeneous liposomes, the abovementioned solution was sequentially extruded through 100 nm polycarbonate films for 10 cycles using an Avanti Mini-Extruder (Avanti Polar Lipids, Inc., Alabaster, AL, U.S.A.). The membrane-impermeable macromolecular inhibitor TEMPO-PEG-TEMPO (30 mg) was added to the obtained liposome solution to prevent the polymerization of monomers outside of the liposome vesicles. The polymerization within the liposome was initiated under nitrogen atmosphere at 30 °C for 2 h to obtain the lipid-coated nanogels (NGs@lipo). The unreacted monomers and TEMPO-PEG-TEMPO were removed through dialysis in 1000 mL of 0.9% NaCl solution for 12 h by changing the dialysis solution every 4 h. To prepare ICG-loaded liposome-coated nanogels (I-NGs@lipo), an in situ polymerization within liposome template was used by using a hydrogel precursor solution with ICG by the same procedure except that indocyanine green (ICG) (2 mg) was added into the same hydrogel precursor solution. To prepare DOX- and ICG-coloaded liposome-coated nanogels (DI-NGs@lipo) by active loading, an in situ polymerization within liposome template was used by using hydrogel precursor solution with ICG and ammonium sulfate ((NH4)2SO4) by the same procedure except that indocyanine green (ICG) (2 mg) and 150 mM (NH4)2SO4 were added into the same hydrogel precursor solution. After removing the unencapsulated ICG, (NH4)2SO4, unreacted monomers and TEMPO-PEG-TEMPO, DOX solution of 6 mg/mL at a drug-to-lipid ratio of 1:8 (weight) was dropwise added to the above (NH4)2SO4-encapsulated I-NGs@lipo solution.50 Furthermore, the solution was incubated at 30 °C for 30 min to allow more doxorubicin to enter the nanogels through the ammonium sulfate gradient method. The obtained DI-NGs@lipo solution was stored at 4 °C for later experiments. To prepare DI-NGs@lipo by passive loading, the I-NGs@lipo prepared above was incubated in the DOX solution (6 mg/mL) for 10 h, and then the DI-NGs@lipo was obtained after ultrafiltration using an Amicon ultra centrifugal filter. DOX-loaded liposomes were prepared according to a previous study.52 To determine the drug loading capacity and encapsulation efficiency, a sample was taken and ultrafiltrated using Amicon ultra centrifugal filter with a molecular weight cutoff of 100 kDa. The amounts of DOX in the filtrate was determined by UV−vis spectrophotometry (TU-1810, Purkinje General Instrument Co, China) at 480 nm using a standard curve method. The amount of entrapped DOX into DI-NGs@lipo was calculated by subtracting the unloaded amount of drug from the total amount used for drug loading. Drug loading content (DLC) and drug loading efficiency (DLE) were calculated from the following equations:

the liposome-coated nanogels a promising platform for theranostic and pharmaceutical applications.40,41,46,47 In this study, an in situ polymerization within liposome template was designed to prepare liposome coated poly(Nisopropylacrylamide-co-acrylamide) (P(NIPAM-co-AAM)) nanogels, which were used as a robust drug-delivery platform to efficiently coencapsulate and simultaneously codeliver a NIR dye indocyanine green (ICG) and high amount of doxorubicin hydrochloride (DOX), denoted as DI-NGs@lipo. As shown in Scheme 1, after the formation of liposomes, the liposomecoated PNIPAM nanogels (NGs@lipo) can be obtained by initiating the intravesicular copolymerization of N-isopropylacrylamide (NIPAM), acrylamide (AAM), and N,N-methylenebis-acrylamide (MBA as cross-linker) in the presence of 2,2′-Azobis (2-methylpropionamide) dihydrochloride (V-50) as a widely used water-soluble initiator for free radical polymerization and ICG as well as ammonium sulfate. To prevent macroscopic hydrogel formation outside liposomes, TEMPOPEG-TEMPO as a membrane-impermeable macromolecular inhibitor has been proven to be able to selectively and effectively inhibit the extravesicular polymerization.48,49 Subsequently, DI-NGs@lipo was obtained after efficiently encapsulating a large number of DOX was into the resultant nanogels by ammonium sulfate gradient method.16,50−52 The obtained DI-NGs@lipo combined the desirable features of both PNIPAM nanogels and PEGylated liposomes. The PNIPAM nanogels as core bring mechanical stability and fast stimuli responsiveness to the final formulation, which are expected to be able to respond to the NIR irradiation-induced hyperthermia and thus achieve quick release of DOX in tumor cells. In addition, the PEGylated liposome as polymerization template not only can obtain NGs@lipo with controlled size, but also can improve their biocompatibility, hemodynamic stability, and prevent premature drug leakage. The structure characters of DI-NGs@ lipo, the stability and photothermal effect of the entrapped ICG, and light-triggered drug rapid release were evaluated. The results demonstrated the great potential of DI-NGs@lipo in chemo-photothermal combination therapy.

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EXPERIMENTAL SECTION

Materials. Distearoylphosphatidyl ethanolamine-polyethylene glycol 2000 (DSPE-PEG), egg phosphatidylcholine (egg PC) with the purity above 99.0% were obtained from Aladdin Biochemical Technology Company CO, Ltd. (Shanghai, China). Indocyanine green (ICG) was purchased from Sigma-Aldrich (St Louis, MO, U.S.A.). Doxorubicin hydrochloride (DOX) with the purity >98.0% was purchased from Beijing Huafeng United Technology Co., Ltd. (Beijing, China). N-isopropylacrylamide (NIPAM) with the purity >98.0%, acrylamide (AAM), ammonium sulfate, 2,2′-Azobis (2-methylpropionamide) dihydrochloride (V-50), cholesterol and N,N-methylene-bis-acrylamide (MBA) were purchased from TCI Chemicals Pvt. Ltd. (Shanghai, China). According to our previous study,48 TEMPOPEG-TEMPO as a membrane-impermeable macromolecular inhibitor was synthesized by conjugating 4-amino-2,2,6,6-tetramethylpiperidine1-oxyl (4-aimno-TEMPO) and O,O′-Bis [2-(N-Succinimidylsuccinylamino)ethyl] polyethylene glycol 3000 in tetrahydrofuran (THF) with triethylamine as catalyst. 4′,6-Diamidino-2-phenylindole (DAPI) and Lysotracker green and Live/Dead viability/cytotoxicity kit were obtained from Invitrogen Corp. (Carlsbad, CA, U.S.A.). An Amicon ultra-4 Ultrafiltration tube with a molecular weight cutoff of 100 kDa was bought from Millipore (U.S.A.). All other chemicals reagents used were commercially available with analytical grade in this study. Preparation and Characterization of NGs@lipo, I-NGs@lipo, and DI-NGs@lipo. The liposomes as polymerization templates with

DLC% =

weight of loaded drug × 100% weight of lipids

(1)

DLE% =

weight of loaded drug × 100% weight of drug in feed

(2)

The hydrodynamic diameter, polydispersity index (PDI) and zetapotential of NGs@lipo and DI-NGs@lipo were measured at 25 °C by dynamic light scattering (DLS) using a Zeta Sizer Nano series Nano-ZS (Malvern. U.K). The results were averaged over triplicate 2426


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808 nm was 1.5 W/cm2 NIR irradiation for 5 min. The culture medium PBS was put in the wells for control groups. Then 20 μL of MTT solution (5 mg/mL) was added. The cells were incubated for 4 h at 37 °C, and the medium was replaced by 150 μL of DMSO to dissolve the resulting purple crystals. The absorption was recorded at 570 nm using a microplate reader (Thermo Scientific Varioskan Flash, Waltham, MA, U.S.A.). The experiments were conducted in triple, and the results were presented as the average ± standard deviation. Cell viability rate (%) was calculated as the following eq 4.

measurements. The morphologies of NGs@lipo and DI-NGs@lipo were observed using a JEM100CXII transmission electron microscope (TEM, JEOL, Japan) with 100 kV acceleration voltage. UV−vis spectrometer (TU-1810, Purkinje General Instrument Co, China) fitted with temperature and stirring controller was used to monitor the absorption of NGs@lipo at different temperatures at 330 nm. The incident light passes through the center of the sample cell fitted with a thermometer. About 4 mL (1.0 mg/mL) of NGs@lipo solution tuned by PBS at pH = 7.4 was added to a UV cell. The VPTT was defined when the absorption of the NGs@lipo solution sharply changed. The VPTT of NGs@lipo was also measured by a STA449F3 simultaneous thermal analyzer (STA, NETZSCH, Germany). The UV absorption spectrum of free DOX, free ICG, DOX-loaded DI-NGs@ lipo by active and passive loading methods were measured by a UV−vis spectrometer. In Vitro Stability. The in vitro stability of DI-NGs@lipo was tested in 5% bull serum albumin (BSA) in PBS by monitoring the hydrodynamic diameter at 37 °C for different incubation time periods on a dynamic light scattering (DLS) equipment. The fluorescence stability of ICG in DI-NGs@lipo was measured by FluoroMax-4 spectrofluorometer (Horiba Jobin Yvon, U.S.A.) at different times, with free ICG as a contrast. In Vitro Photothermal Effect. A NIR laser (808 nm, MDL-N808, Changchun New Industry Optoelectronic Technology Co., Ltd. China) was used in the experiments. PBS buffer solution, solution of free ICG, I-NGs@lipo and DI-NGs@lipo at the final ICG concentration of 25 μg/mL were put into 1.5 mL centrifuge tubes, respectively, and irradiated by the 808 nm laser with a power density of 1.5 W/cm2 for 6 min. Real-time imaging was monitored and infrared thermographic maps were obtained by the infrared thermal imaging camera (FLIR A5, FLIR Systems, U.S.A.). The size of DI-NGs@lipo at different time points under the irradiation of 808 nm laser was characterized by dynamic light scattering (DLS). In Vitro Drug Release. In vitro release of DOX from DI-NGs@ lipo was determined by adding 1.5 mL of DI-NGs@lipo solution into a dialysis tube with a molecular weight cutoff of 8000 Da (Slide-A-Lyzer, Thermo Scientific, U.S.A.). The dialysis tube was immersed into 10 mL of PBS at pH 7.4 and shaken at different temperatures (37 and 42 °C) in thermostatic shaking bed (SHZ-82, Champion Instruments, Changzhou, China). The drug release triggered by NIR light were investigated according to the similar procedure except that the samples were irradiated for 5 min at 37 °C using NIR laser (808 nm, 1.5 W/cm2). At predetermined time intervals, 5.0 mL of the release medium was withdrawn followed by replacement with an equal volume of fresh PBS to continue further study. The release amount of DOX was quantified by UV−vis spectrophotometry. The procedure about drug release from DOX-loaded liposomes was the same as above. All the results were the mean of three test runs, and all data were presented as the mean ± SD. The cumulative drug release percentage was calculated using the following equation: n−1

Er(%) =

Vt ∑1

C i + V0Cn

mDOX

× 100%

cell viability (%) =

I0 − I1 × 100% I0

(4)

where I0 was the absorbance of the cells incubated with the culture medium, and I1 was the absorbance of the cells incubated with different formulations. In Vitro Cellular Uptake. The cellular uptake and intracellular drug release were evaluated on 4T1 murine breast cancer cells lines. Confocal laser scanning microscope (CLSM) was used to qualitatively observe the cellular uptake of free DOX and DI-NGs@lipo by 4T1 cells. Intracellular release of DOX from DI-NGs@lipo was followed with fluorescence microscope using 4T1 cells. The cells were cultured on specified wells at 5000 cells per well, incubated at 37 °C for 24 h, and then culture medium was replaced by fresh medium containing the free DOX (10 μg/mL) or DI-NGs@lipo (including 10 μg/mL DOX and 8.5 μg/mL ICG) at pH 7.4. After incubation for 2 h at 37 °C, the center region in the 12-well plate of DI-NGs@lipo was exposed (or left unexposed) to 808 nm wavelength laser irradiation (1.5 W/cm2) for 5 min. In order to observe the cell uptake at 42 °C, some cells treated with DI-NGs@lipo were incubated at 42 °C for 30 min. The cells were allowed to incubate for 2 h, and the cells were washed with PBS (10 mM, pH 7.4). Thereafter, the cell nuclei were stained with DAPI (blue), the lysosomes were stained with LysoTracker Deep red (green), and then these cells were observed by CLSM (Olympus, Tokyo, Japan). The fluorescence signal was imaged at λEx (485 nm) for DOX. Hemolysis Assay. Red blood cells (RBCs) were isolated from 600 μL of fresh whole blood by centrifuging at 2000 rpm for 5 min and washed five times with PBS pH 7.4. Then the RBCs were resuspended in 6 mL sterile PBS. 0.2 mL of the RBCs solution was added to 0.8 mL NGs@lipo solution in PBS at a concentration of 100 μg/mL. The positive reference (100% lysis) was a blood/deionized water mixture, and the negative reference (0% lysis) was a blood/PBS mixture. Three parallel samples were made in each group, incubated at 37 °C for 4 h, and the mixture was centrifuged at 2000 rpm for 5 min. The optical density (OD) of the supernatant was read at 545 nm using a UV−vis spectrophotometer. The hemolytic ratios of the samples were calculated as follows: hemolytic ratio (%) =

■

(3)

× 100%

sample absorbance − negative control positive control − negative control (5)

RESULTS AND DISCUSSION Synthesis and Characterization of NGs@lipo. Liposomecoated nanogels, consisted of a hydrogel core and a PEGylated liposomal shell, represent an intriguing nanoplatform for drug delivery.40,43,44 In this study, the liposome-coated PNIPAM nanogels, i.e. NGs@lipo, were prepared through in situ liposome-template polymerization. The liposomal vesicles as a nanoreactor was used to encapsulate the hydrogel formation mixture including monomers, cross-linkers, and initiators with or without ICG and ammonium sulfate. The size of drug-free NGs@lipo was simply controlled by extrusion through a nanopore polycarbonate filter with 100 nm size. After the formation of liposomes by sonication in an ice−water bath and nanoporeextrusion, the polymerization of NIPAM and AAM in the liposomes was initiated under nitrogen atmosphere at 30 °C for

where Er is the cumulative release amount, the mDOX represents the amounts of DOX in the DI-NGs@lipo of dialysis bag, Ve is the volume of replaced medium (5 mL), V0 is the total volume of the released media (V0 = 10 mL), Ci and Cn represent the concentration of DOX in the sample. In Vitro Cytotoxicity. MTT assay was utilized in appraising the cellular toxicity of the designed formulations. 4T1 cells (5000 per well) were seeded into a 96-well plate cultured in 100 μL of complete DMEM and incubated at 37 °C with 5% CO2. After 24 h, the supernatants were discarded, and the cells were washed twice with PBS (pH 7.4). First, we studied the cytotoxicity of NGs@lipo and I-NGs@ lipo at a lipid concentration of 0.5, 50, 100, 250, 500, 1000 μg/mL. Free DOX and DI-NGs@lipo were also put into the wells for 24 h at a DOX concentration of 0.125, 1.25, 2.5, 5, 10, 20, 40 μg/mL, respectively. In different control groups, the concentrations of DOX and ICG were 10 and 8.5 μg/mL, separately. The presence of laser of 2427


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Figure 1. Characterizations of NGs@lipo and DI-NGs@lipo. TEM image of NGs@lipo (A) and DI-NGs@lipo (B); Hydrodynamic diameter and thermoresponsiveness of NGs@lipo (C); Zeta potentials of NGs@lipo and DI-NGs@lipo at pH 7.4 (D); Temperature dependence of UV absorption at 330 nm of NGs@lipo in aqueous solutions (E); Simultaneous thermal analyzer curve of NGs@lipo (scanning rate 2 °C/min, aluminum pans) (F).

dispersion index (PDI) changed from 0.191 to 0.090. Therefore, there was a decrease of size and volume of NGs@lipo when temperature increased from 25 to 42 °C. The zeta potential of NGs@lipo and DI-NGs@lipo in diluted PBS solution at pH 7.4 was tested and shown in Figure 1D. The zeta potential of blank NGs@lipo was −4.23 ± 0.3 mV, which was close to neutral. The zeta potential of DI-NGs@lipo was −10.6 ± 0.65 mV. It can be found that the drug loading process has little effect on the zeta potential of NGs@lipo. To further confirm the temperature sensitivity of NGs@lipo, we measured the UV absorption of NGs@lipo at different temperature, as shown in Figure 1E. It can be observed that the absorption sharply increased at near 40 °C, which was contributed to that the hydrophilic PNIPAM chains transferred into hydrophobic chains and thus the NGs@lipo dispersion solution changed from transparent to turbid at this temperature. In addition, simultaneous thermal analyzer (STA) was employed to study the thermo-sensitivity of NGs@lipo in aqueous solution. As shown in Figure 1F, it was apparent that NGs@lipo presented thermo-sensitivity with VPTT about 40 °C due to phase transition of the P(NIPAM-co-AAM) nanogels. Consequently, the results demonstrated that the VPTT of NGs@lipo was close to 40 °C, which was higher than human body temperature and thus provided an effective approach to control drug release by temperature mediation. In Vitro Stability of DI-NGs@lipo. Stability is one of the critical factors in ensuring long shelf life, high safety, and clinical efficacy of drug formulations, especially for lipid-based colloidal suspensions.53 In our study, a size stability assay of DI-NGs@ lipo was evaluated in PBS containing 5% BSA for 5 days at 37 °C (Figure 2A). The particle size of DI-NGs@lipo almost remained the original size without precipitation or phase separation in PBS containing 5% BSA for 5 days. The polydispersity index (PDI) was between 0.17 and 0.20. The good

2 h in the presence of macromolecular inhibitor (TEMPOPEG-TEMPO). The TEMPO-PEG-TEMPO as a membraneimpermeable macromolecular inhibitor has been proven to be able to selectively inhibit the extravesicular polymerization reaction while maintaining the intravesicular reaction alive.48 As shown in Figure S1, TEMPO-PEG-TEMPO was also found to be able to completely inhibit the polymerization of hydrogel forming solution at 30 °C for 3 h or even longer time. The DOX drug was loaded into the NGs@lipo by ammonium sulfate gradient active loading method. The drug-free NGs@lipo and drug-loaded DI-NGs@lipo derived from in situ liposometemplate polymerization were visualized with TEM and characterized by DLS, as shown in Figure 1A,B, respectively. Both the NGs@lipo and DI-NGs@lipo in the dry state generally exhibit spherical morphology with good monodispersity. The particle sizes of both NGs@lipo and DI-NGs@lipo in TEM images range from about 103 ± 10 nm. Figure S2 shows the TEM images of blank liposomes. The circular structures reflect the presence of hollow vesicles. Compared with the TEM images of liposomes, the TEM images of NGs@lipo and DI-NGs@lipo are more spherical and solid, which may confirm the formation of nanogels in the liposomal intravesicular space. The TEM photo of DI-NGs@lipo (Figure 1B) exhibited a more compact and spherical morphology, which may be due to the presence of complexes of DOX and ammonium sulfate. The double-layered lipid shell outside the nanogels were not observed, which may be due to the collapse of polymeric nanogels core during the process of TEM sample preparation. The hydrodynamic sizes and thermoresponsiveness of NGs@lipo were confirmed by monitoring the size change of incubation at different temperature using dynamic light scattering technique, as shown in Figure 1C. The hydrodynamic diameter of NGs@lipo was measured at 106 ± 7.3 nm at 25 °C, but decreased to 72 ± 3.6 nm when temperature increased to 42 °C. The particle 2428


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Figure 2. Physicochemical properties of DI-NGs@lipo. Size stability of DI-NGs@lipo in PBS containing 5% BSA at 37 °C (A); Fluorescence stability of free ICG and ICG in DI-NGs@lipo (B); The UV−vis spectra of free ICG, free DOX, DOX-loaded DI-NGs@lipo by active loading and passive loading methods (C); Photographs of NGs@lipo (I), I-NGs@lipo (II) and DI-NGs@lipo (III) (D); Fluorescence emission spectra of DI-NGs@lipo at different concentration. Excitation wavelength at 480 nm related to DOX (E) and excitation wavelength at 780 nm related to ICG (F).

that the ICG and DOX were encapsulated into the NGs@lipo. Moreover, as shown in Figure 2E,F, it can be found that DOX and ICG presented independent fluorescence and concentration-dependent fluorescence intensity when they were coloaded in DI-NGs@lipo, which may be advantageous to track in vitro and in vivo. In Vitro Photothermal Effects. To investigate the photothermal property, DI-NGs@lipo solution was exposed to an NIR laser (808 nm, 1.5 W/cm2) for 6 min, and the temperature was simultaneously recorded per 30 s using an infrared thermal imaging camera. As shown in Figure 3A,B, only 1.5 °C increase on temperature was observed for PBS after 6 min irradiation. By contrast, an obvious temperature increase was found for I-NGs@lipo and DI-NGs@lipo under NIR irradiation. The solution temperatures of both I-NGs@lipo and DI-NGs@ lipo were increased to about 52 °C after 6 min irradiation, which were appreciably higher than that of free ICG solution (about 49 °C). The temperature increase of free ICG was slightly lower than that of I-NGs@lipo and DI-NGs@lipo. This may be due to the improved stability of ICG in NGs@lipo, as demonstrated above. Moreover, the ICG encapsulation in the I-NGs@lipo or DI-NGs@lipo possessed a highly condensed concentration over that of free ICG, and the enclosure of NGs@lipo entrapped the photothermal radiation, resulting in the lower heat dissipation and higher energy efficiency in the I-NGs@lipo or DI-NGs@lipo after laser irradiation.55,56 Considering the thermo-sensitivity of NGs@lipo, the size change of DI-NGs@lipo under NIR irradiation was also investigated. As shown in Figure 3C, the hydrodynamic size of DI-NGs@lipo significantly decreased from 108 to 74 nm under 808 nm irradiation for 6 min. The significant decrease in DI-NGs@lipo size can be ascribed to the shrinkage of nanogels from the hydrophilic-to-hydrophobic transition of PNIPAM chains. These results not only further confirmed the thermo-sensitivity

stability of DI-NGs@lipo can be ascribed to the excellent steric stabilization of PEGylated liposome shell to prevent colloidal agglomeration and the inside three-dimensional cross-linking network for stabilizing the liposome. ICG was proved to an effective photosensitive reagent by laser-excitation heat for photothermal therapy.54 However, the application of the free ICG is limited by its numerous defects, including poor aqueous stability, concentration-dependent aggregation, and rapid elimination from the body.55 In this study, we also investigated the fluorescence stability of ICG in DI-NGs@lipo. As shown in Figure 2B, the fluorescence measurement illustrated that fluorescence intensity of ICG in DI-NGs@lipo remained nearly 97% for 1 days and above 85% after 7 days, while fluorescence intensity of free ICG decreased to 66% of initially intensity after 1 day and degraded to 2% after 7 days. These results suggested that fluorescence stability of ICG was significantly improved by encapsulation of NGs@lipo. The higher fluorescence stability of ICG in DI-NGs@lipo may be due to the ICG entrapped in nanogels was isolated form the surrounding environment.55,56 Figure 2C revealed that the obtained DI-NGs@lipo showed a strong DOX absorption at 485 nm and ICG absorption at 800 nm, which certificated that DOX and ICG were successfully loaded. The spectra also showed that the content of DOX by active loading was higher than the passive loading. A large number of studies have confirmed that the ammonium sulfate gradient active loading method can significantly increase the DOX loading content in liposomal nanocarriers.16,50−52,57 The drug loading content (DLC) of DI-NGs@lipo by passive loading and active loading were about 2.5‰ and 6.6%, respectively, which was calculated on the basis of lipids weight. The drug loading efficiency (DLE) were about 29.6‰ and 80.2%, respectively. The apparent photographs of NGs@lipo before and after ICG and DOX loading were shown in the Figure 2D. The significant changes of color of NGs@lipo further indicated 2429


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Figure 3. Photothermal effect of DI-NGs@lipo under NIR irradiation of 808 nm laser (1.5 W/cm2, 6 min). Peak temperature maps of PBS, free ICG, I-NGs@lipo, and DI-NGs@lipo recorded with an infrared thermal imaging camera (A); Temperature profiles of PBS, free ICG, and both I-NGs@lipo and DI-NGs@lipo dispersions (B); Hydrodynamic size of DI-NGs@lipo at different time points under NIR irradiation (C).

Figure 4. Drug release profiles of DOX-loaded liposomes and DI-NGs@lipo. Cumulative release of DOX from DOX-loaded liposomes (A) and DI-NGs@lipo (B) at 37 and 42 °C; Cumulative release of DOX from DI-NGs@lipo with and without NIR irradiation for 5 min (C).

will occur due to the hydrophilic-to-hydrophobic transition of PNIPAM chains. The collapse and shrinkage of nanogels core not only can break the liposomes shells, facilitating the drug release, but also can squeeze out the loaded drug, thus leading to an increase in drug release under 42 °C. We further investigated the release of DOX from DI-NGs@lipo under NIR irradiation (808 nm, 1.5 W/cm2, 5 min), as shown in Figure 4C. In a short time of 30 min, nearly no DOX release from DI-NGs@ lipo at 37 °C without NIR irradiation was observed. However, after NIR irradiation of 5 min, drug release was accelerated significantly, and the total release of DOX increased to 22.3% at 30 min, indicating that NIR laser can trigger drug release from DI-NGs@lipo effectively. It was well-known that the intracellular-triggered drug release is not only an efficient strategy to increase therapy efficacy but also an important method to reduce the side-effects and suppress drug resistance. The DI-NGs@lipo presented a temperature-dependent drug release profile, which should be very beneficial for cancer treatment. Most of the loaded DOX will remain in DI-NGs@lipo for a considerable length of time when the DI-NGs@lipo stay in the extracellular space under normal physiological conditions. However, the encapsulated DOX will be quickly released when the DI-NGs@lipo is taken up by the tumor cells under NIR irradiation due to hyperthermia

of DI-NGs@lipo but also indicated the great potential of DI-NGs@lipo in NIR-triggered drug release by the photothermal-induced nanostructural transition. In Vitro Drug Release. To demonstrate hyperthermiatrigged drug release from DI-NGs@lipo, the drug release from the DOX-loaded liposomes and DI-NGs@lipo were comparatively investigated in 37 and 42 °C. The DOX release results from the liposome were shown in Figure 4A. There was almost no difference in the release of DOX from the DOX-loaded liposomes at 37 and 42 °C, with a cumulative release of 15% within 8 h. However, the DI-NGs@lipo exhibited a temperature-dependent release profile (Figure 4B). The DOX release from DI-NGs@lipo at 37 °C was very low. Only about 11% of the total encapsulated DOX was released from DI-NGs@lipo incubated in the release medium of PBS within 8 h. When DI-NGs@lipo was incubated with PBS at 42 °C, the release of DOX was significantly accelerated, reaching a cumulative release of about 12.7% of total encapsulated drug in 1 h and 34.2% in 8 h. This may be due to that the cross-linked nanogels cores in liposome at 37 °C could efficiently store drugs and thus delay drug release. The temperature increased to 42 °C, which was higher than VPTT of the DI-NGs@lipo (40 °C), and thus the collapse and shrinkage of nanogels in liposomes 2430


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Figure 5. CLSM images of 4T1 cells incubated with free DOX, DI-NGs@lipo, DI-NGs@lipo at 42 °C for 30 min, DI-NGs@lipo with NIR irradiation for 5 min, respectively. Nuclei were stained in blue, DOX was in red (Scale bar: 10 μm.).

a high concentration of 1000 μg/mL (Figure 6A), manifesting that NGs@lipo and I-NGs@lipo were safe and biocompatibility for drug delivery. Meanwhile, the free DOX and DI-NGs@lipo (contain different concentrations of DOX) exhibited similar toxicity to the 4T1 cell lines after 24 h of incubation without irradiation (Figure 6B). Compared to cells only treated with I-NGs@lipo containing 8.5 μg/mL ICG with viability of 97.7%, an obviously enhanced therapeutic effect was observed for 4T1 cell treated with I-NGs@lipo under NIR irradiation, which can be ascribed to NIR irradiation-induced heat toxicity. On the other hand, in comparison with the groups of I-NGs@lipo and I-NGs@lipo + laser, the DI-NGs@lipo under NIR irradiation had obvious anticancer activity (Figure 6C). Furthermore, it can be seen that the cells treated with the same concentration of free DOX drug (10 μg/mL) still survived at a rate of 50%. The cells treated with NGs@lipo under NIR irradiation only maintained about 24% cell viability, which was 2 times as low as that of the cells treated with DI-NGs@lipo without NIR irradiation and free DOX. These results indicated the synergetic effect of NGs@lipo under NIR irradiation, which was caused by the combination of laser-induced hyperthermia effect and the NIR-induced hyperthermia triggered DOX release. In addition, hyperthermia enhanced the permeability of cells and increased the sensitivity of tumor cells to chemotherapy drugs.19,20,23 Conclusively, DI-NGs@lipo designed herein as nanoplatform for codelivery of DOX and ICG exhibited very promising properties, which can synergistically improve the tumor-cell-killing efficiency and thus has great potential in chemo-photothermal therapy. Hemocompatibility is an important criterion for biocompatibility of nanoparticle drug-delivery systems. The biocompatibility of NGs@lipo was examined by hemolysis assay using PBS and deionized water as negative and positive control, respectively, as shown in Figure 6D. After incubating the NGs@lipo with RBCs in PBS for 4 h at 37 °C at a concentration of 100 μg/mL, the NGs@lipo dispersions did not exhibit any

induced nanostructural transition. Therefore, the efficacy of therapy can be significantly improved due to high and sustained local drug concentrations in the tumor cells. In Vitro Cell Uptake. Efficient cellular uptake plays a key prerequisite for drug treatment efficacy. To demonstrate whether NIR light-induced hyperthermia affected the internalization, the cellular uptake of free DOX and DI-NGs@lipo in 4T1 cells following with or without NIR irradiation was determined. The cellular uptake at 42 °C was performed as a control. The subcellular localization of DOX was investigated by confocal laser scanning microscopy (CLSM). As shown in Figure 5, free DOX mainly distributed in cell nuclei in 4T1 cells after 4 h of incubation, indicating the entering of free DOX by a passive diffusion mechanism, which corresponded with the previous report.58,59 In addition, the remarkably brighter red fluorescence of DOX and most of DOX distributed in nuclei of the 4T1 cells treated by DI-NGs@lipo + laser were observed. However, the 4T1 cells treated only by DI-NGs@lipo without laser showed weaker red fluorescence. The low DOX distribution in the nucleus of DI-NGs@lipo was attributed to the difficult release of the DOX tightly wrapped by nanogels. In comparison, higher DOX distribution was observed at nucleus in the cells treated by DI-NGs@lipo + laser, which revealed that the hyperthermia caused by laser make the collapse of nanogels and facilitate the DOX release. In addition, the similar phenomenon to the cells treated by DI-NGs@lipo at 42 °C was observed, further verifying temperature-dependent release profile of DI-NGs@lipo. Consequently, the results demonstrated that DI-NGs@lipo with temperature-responsive nanogels cores had a high potential as the carrier for intracellular drug delivery. In Vitro Cytotoxicity and Biocompatibility of NGs@ lipo, I-NGs@lipo, and DI-NGs@lipo. The cytotoxicities of drug-free NGs@lipo and I-NGs@lipo were evaluated for the cell compatibility of the drug-delivery system. The cell viability remained at 90% even after treatment with DOX-free carriers at 2431


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Figure 6. In vitro cytotoxicity and biocompatibility. Cell viability of 4T1 cells treated with NGs@lipo and I-NGs@lipo (A) and treated with free DOX and DI-NGs@lipo containing various DOX concentrations (B); Cell viability of 4T1 cells treated with NGs@lipo, NIR laser, Free DOX, I-NGs@lipo and DI-NGs@lipo with or without NIR irradiation. Each bar represents the mean ± SD of six experiments. *P < 0.05, **P < 0.01, and ***P < 0.001 (C). Photograph of hemolysis of erythrocytes incubated with NGs@lipo at concentration of 100 μg/mL for 4 h and hemolytic ratio measured by UV−vis spectrophotometry at 545 nm. Deionized water and PBS are used as positive and negative control, respectively (D).

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marked hemolytic activities in the RBCs. The hemolytic percentage of NGs@lipo was lower than 2% at the tested concentration, exhibiting a very high hemocompatibility. These results indicated that the PEGylated liposomes-coated nanogels have excellent hemocompatibility, which may enable them to be safe for various biomedical applications.

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsbiomaterials.8b00379. Additional details including inhibition effect of TEMPOPEG-TEMPO on polymerization of hydrogel forming solution; TEM image of liposomes (PDF)

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CONCLUSIONS In this study, an in situ liposome-template polymerization was used to prepare liposome-coated poly(N-isopropylacrymideco-acrylamide)(P(NIPAM-co-AAM)) nanogels, which can efficiently coencapsulate ICG and DOX by an ammonium sulfate gradient method. The DOX/ICG coloaded hybrid nanogels with uniform and controlled nanoscale size (denoted as DI-NGs@lipo) integrated the desirable functions of PEGylated liposomes and thermosensitive nanogels. The PEGylated liposomes shell provided excellent storage stability, hemodynamic stability, and fluorescence stability. Meanwhile, the thermosensitive nanogels cores endowed DI-NGs@lipo with VPTT at about 40 °C, allowing for NIR-induced hyperthermia controlled transformation and thus quick DOX release. As a result, the concurrent chemo-photothermal therapy was achieved by NIR light, as NIR not only induced hyperthermia but also simultaneously triggered quick DOX release by thermotriggered nanogels transformation. Notably, the DI-NGs@lipo combined desirable multifunctionality for chemo-photothermal therapies and can synergistically improve the cancer-cell-killing efficiency, demonstrating great potential in photoinduced cancer therapy.

AUTHOR INFORMATION

Corresponding Author

*E-mail [email protected]. ORCID

Anjie Dong: 0000-0002-7348-3221 Liandong Deng: 0000-0001-5906-236X Jianhua Zhang: 0000-0001-7833-9715 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was supported by National Natural Science Foundation of China (31470925, 31671021, and 31470963) and Tianjin Research Program of Application Foundation and Advanced Technology (15JCQNJC03000).

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REFERENCES

(1) Blanco, E.; Shen, H.; Ferrari, M. Principles of nanoparticle design for overcoming biological barriers to drug delivery. Nat. Biotechnol. 2015, 33 (9), 941−951.

2432


Article

ACS Biomaterials Science & Engineering (2) Shi, J.; Kantoff, P. W.; Wooster, R.; Farokhzad, O. C. Cancer nanomedicine: progress, challenges and opportunities. Nat. Rev. Cancer 2017, 17 (1), 20−37. (3) Chen, G.; Roy, I.; Yang, C.; Prasad, P. N. Nanochemistry and Nanomedicine for Nanoparticle-based Diagnostics and Therapy. Chem. Rev. 2016, 116 (5), 2826−2885. (4) Ramasamy, T.; Ruttala, H. B.; Gupta, B.; Poudel, B. K.; Choi, H. G.; Yong, C. S.; Kim, J. O. Smart chemistry-based nanosized drug delivery systems for systemic applications: A comprehensive review. J. Controlled Release 2017, 258, 226−253. (5) Karimi, M.; Ghasemi, A.; Sahandi Zangabad, P.; Rahighi, R.; Moosavi Basri, S. M.; Mirshekari, H.; Amiri, M.; Shafaei Pishabad, Z.; Aslani, A.; Bozorgomid, M.; Ghosh, D.; Beyzavi, A.; Vaseghi, A.; Aref, A. R.; Haghani, L.; Bahrami, S.; Hamblin, M. R. Smart micro/ nanoparticles in stimulus-responsive drug/gene delivery systems. Chem. Soc. Rev. 2016, 45 (5), 1457−1501. (6) Kamaly, N.; Yameen, B.; Wu, J.; Farokhzad, O. C. Degradable Controlled-Release Polymers and Polymeric Nanoparticles: Mechanisms of Controlling Drug Release. Chem. Rev. 2016, 116 (4), 2602− 2663. (7) Zhan, Y.; Gonçalves, M.; Yi, P.; Capelo, D.; Zhang, Y.; Rodrigues, J.; Liu, C.; Tomás, H.; Li, Y.; He, P. Thermo/redox/pH-triple sensitive poly(N-isopropylacrylamide-co-acrylic acid) nanogels for anticancer drug delivery. J. Mater. Chem. B 2015, 3 (20), 4221−4230. (8) Mura, S.; Nicolas, J.; Couvreur, P. Stimuli-responsive nanocarriers for drug delivery. Nat. Mater. 2013, 12 (11), 991−1003. (9) Li, Y.; Xiao, K.; Zhu, W.; Deng, W.; Lam, K. S. Stimuli-responsive cross-linked micelles for on-demand drug delivery against cancers. Adv. Drug Delivery Rev. 2014, 66, 58−73. (10) Wang, Y.; Shim, M. S.; Levinson, N. S.; Sung, H. W.; Xia, Y. Stimuli-Responsive Materials for Controlled Release of Theranostic Agents. Adv. Funct. Mater. 2014, 24 (27), 4206−4220. (11) Cheng, W.; Gu, L.; Ren, W.; Liu, Y. Stimuli-responsive polymers for anti-cancer drug delivery. Mater. Sci. Eng., C 2014, 45, 600−608. (12) Shanmugam, V.; Selvakumar, S.; Yeh, C. S. Near-Infrared LightResponsive Nanomaterials in Cancer Therapeutics. Chem. Soc. Rev. 2014, 43 (17), 6254−6287. (13) Zhang, Z.; Wang, J.; Chen, C. Near-infrared light-mediated nanoplatforms for cancer thermo-chemotherapy and optical imaging. Adv. Mater. 2013, 25 (28), 3869−3880. (14) Zou, L.; Wang, H.; He, B.; Zeng, L.; Tan, T.; Cao, H.; He, X.; Zhang, Z.; Guo, S.; Li, Y. Current Approaches of Photothermal Therapy in Treating Cancer Metastasis with Nanotherapeutics. Theranostics 2016, 6 (6), 762−772. (15) Gao, H.; Bi, Y.; Wang, X.; Wang, M.; Zhou, M.; Lu, H.; Gao, J.; Chen, J.; Hu, Y. Near-Infrared guided thermal-responsive nanomedicine against orthotopic superficial bladder cancer. ACS Biomater. Sci. Eng. 2017, 3 (12), 3628−3634. (16) Camacho, K. M.; Menegatti, S.; Vogus, D. R.; Pusuluri, A.; Fuchs, Z.; Jarvis, M.; Zakrewsky, M.; Evans, M. A.; Chen, R.; Mitragotri, S. DAFODIL: A novel liposome-encapsulated synergistic combination of doxorubicin and 5FU for low dose chemotherapy. J. Controlled Release 2016, 229, 154−162. (17) Deng, Z.; Xiao, Y.; Pan, M.; Li, F.; Duan, W.; Meng, L.; Liu, X.; Yan, F.; Zheng, H. Hyperthermia-triggered drug delivery from iRGDmodified temperature-sensitive liposomes enhances the anti-tumor efficacy using high intensity focused ultrasound. J. Controlled Release 2016, 243, 333−341. (18) Zheng, T.; Li, G. G.; Zhou, F.; Wu, R.; Zhu, J. J.; Wang, H. Gold-nanosponge-based multistimuli-responsive drug vehicles for targeted chemo-photothermal therapy. Adv. Mater. 2016, 28 (37), 8218−8226. (19) Li, F.; Yang, H.; Bie, N.; Xu, Q.; Yong, T.; Wang, Q.; Gan, L.; Yang, X. Zwitterionic temperature/redox-sensitive nanogels for nearinfrared light-triggered synergistic thermo-chemotherapy. ACS Appl. Mater. Interfaces 2017, 9 (28), 23564−23573. (20) Yu, Y.; Zhang, Z.; Wang, Y.; Zhu, H.; Li, F.; Shen, Y.; Guo, S. A new NIR-triggered doxorubicin and photosensitizer indocyanine green co-delivery system for enhanced multidrug resistant cancer treatment

through simultaneous chemo/photothermal/photodynamic therapy. Acta Biomater. 2017, 59, 170−180. (21) Li, M.; Teh, C.; Ang, C. Y.; Tan, S. Y.; Luo, Z.; Qu, Q.; Zhang, Y.; Korzh, V.; Zhao, Y. Near-Infrared Light-Absorptive Stealth Liposomes for Localized Photothermal Ablation of Tumors Combined with Chemotherapy. Adv. Funct. Mater. 2015, 25 (35), 5602−5610. (22) Wang, H.; Mukherjee, S.; Yi, J.; Banerjee, P.; Chen, Q.; Zhou, S. Biocompatible Chitosan-Carbon Dot Hybrid Nanogels for NIRImaging-Guided Synergistic Photothermal-Chemo Therapy. ACS Appl. Mater. Interfaces 2017, 9 (22), 18639−18649. (23) Wang, J.; Liu, Y.; Ma, Y.; Sun, C.; Tao, W.; Wang, Y.; Yang, X.; Wang, J. NIR-Activated Supersensitive Drug Release Using Nanoparticles with a Flow Core. Adv. Funct. Mater. 2016, 26 (41), 7516− 7525. (24) Wang, H.; Yi, J.; Mukherjee, S.; Banerjee, P.; Zhou, S. Magnetic/ NIR-thermally responsive hybrid nanogels for optical temperature sensing, tumor cell imaging and triggered drug release. Nanoscale 2014, 6 (21), 13001−13011. (25) Hang, C.; Zou, Y.; Zhong, Y.; Zhong, Z.; Meng, F. NIR and UVresponsive degradable hyaluronic acid nanogels for CD44-targeted and remotely triggered intracellular doxorubicin delivery. Colloids Surf., B 2017, 158, 547−555. (26) Cinay, G. E.; Erkoc, P.; Alipour, M.; Hashimoto, Y.; Sasaki, Y.; Akiyoshi, K.; Kizilel, S. Nanogel-integrated pH-responsive composite hydrogels for controlled drug delivery. ACS Biomater. Sci. Eng. 2017, 3 (3), 370−380. (27) Li, M.; Tang, Z.; Sun, H.; Ding, J.; Song, W.; Chen, X. pH and reduction dual-responsive nanogel cross-linked by quaternization reaction for enhanced cellular internalization and intracellular drug delivery. Polym. Chem. 2013, 4 (4), 1199−1207. (28) Wang, H.; Ke, F.; Mararenko, A.; Wei, Z.; Banerjee, P.; Zhou, S. Responsive polymer−fluorescent carbon nanoparticle hybrid nanogels for optical temperature sensing, near-infrared light-responsive drug release, and tumor cell imaging. Nanoscale 2014, 6 (13), 7443−7452. (29) Wu, H. Q.; Wang, C. C. Biodegradable Smart Nanogels: A New Platform for Targeting Drug Delivery and Biomedical Diagnostics. Langmuir 2016, 32 (25), 6211−6225. (30) Ramos, J.; Imaz, A.; Forcada, J. Temperature-sensitive nanogels: poly (N-vinylcaprolactam) versus poly (N-isopropylacrylamide). Polym. Chem. 2012, 3 (4), 852−856. (31) Qian, K.; Ma, Y.; Wan, J.; Geng, S.; Li, H.; Fu, Q.; Peng, X.; Kan, X.; Zhou, G.; Liu, W.; Xiong, B.; Zhao, Y.; Zheng, C.; Yang, X.; Xu, H. The studies about doxorubicin-loaded p(N-isopropylacrylamide-co-butyl methylacrylate) temperature-sensitive nanogel dispersions on the application in TACE therapies for rabbit VX2 liver tumor. J. Controlled Release 2015, 212, 41−49. (32) Zhu, X.; Sun, Y.; Chen, D.; Li, J.; Dong, X.; Wang, J.; Chen, H.; Wang, Y.; Zhang, F.; Dai, J.; Pirraco, R. P.; Guo, S.; Marques, A. P.; Reis, R. L.; Li, W. Mastocarcinoma therapy synergistically promoted by lysosome dependent apoptosis specifically evoked by 5-Fu@ nanogel system with passive targeting and pH activatable dual function. J. Controlled Release 2017, 254, 107−118. (33) Zhang, L.; Yang, Z.; Zhu, W.; Ye, Z.; Yu, Y.; Xu, Z.; Ren, J.; Li, P. Dual-stimuli-responsive, polymer-microsphere-encapsulated CuS nanoparticles for magnetic resonance imaging guided synergistic chemo-photothermal therapy. ACS Biomater. Sci. Eng. 2017, 3 (8), 1690−1701. (34) Yang, H.; Wang, Q.; Huang, S.; Xiao, A.; Li, F.; Gan, L.; Yang, X. Smart pH/Redox Dual-Responsive Nanogels for On-Demand Intracellular Anticancer Drug Release. ACS Appl. Mater. Interfaces 2016, 8 (12), 7729−7738. (35) Chen, Y. S.; Yoon, S. J.; Frey, W.; Dockery, M.; Emelianov, S. Dynamic contrast-enhanced photoacoustic imaging using photothermal stimuli-responsive composite nanomodulators. Nat. Commun. 2017, 8, 15782. (36) Tang, J.; Cui, X.; Caranasos, T. G.; Hensley, M. T.; Vandergriff, A. C.; Hartanto, Y.; Shen, D.; Zhang, H.; Zhang, J.; Cheng, K. Heart Repair Using Nanogel-Encapsulated Human Cardiac Stem Cells in 2433


Article

ACS Biomaterials Science & Engineering Mice and Pigs with Myocardial Infarction. ACS Nano 2017, 11 (10), 9738−9749. (37) Soni, K. S.; Desale, S. S.; Bronich, T. K. Nanogels: An overview of properties, biomedical applications and obstacles to clinical translation. J. Controlled Release 2016, 240, 109−126. (38) Li, Y.; Maciel, D.; Rodrigues, J.; Shi, X.; Tomas, H. Biodegradable Polymer Nanogels for Drug/Nucleic Acid Delivery. Chem. Rev. 2015, 115 (16), 8564−8608. (39) Raemdonck, K.; Braeckmans, K.; Demeester, J.; De Smedt, S. C. Merging the best of both worlds: hybrid lipid-enveloped matrix nanocomposites in drug delivery. Chem. Soc. Rev. 2014, 43 (1), 444− 472. (40) Kazakov, S. Liposome-nanogel structures for future pharmaceutical applications: an updated review. Curr. Pharm. Des. 2016, 22 (10), 1391−1413. (41) Kazakov, S.; Levon, K. Liposome-Nanogel Structures for Future Pharmaceutical Applications. Curr. Pharm. Des. 2006, 12 (36), 4713− 4728. (42) Hadinoto, K.; Sundaresan, A.; Cheow, W. S. Lipid-polymer hybrid nanoparticles as a new generation therapeutic delivery platform: a review. Eur. J. Pharm. Biopharm. 2013, 85, 427−443. (43) Elnaggar, Y. S.; El-Refaie, W. M.; El-Massik, M. A.; Abdallah, O. Y. Lecithin-based nanostructured gels for skin delivery: an update on state of art and recent applications. J. Controlled Release 2014, 180, 10− 24. (44) Park, J.; Wrzesinski, S. H.; Stern, E.; Look, M.; Criscione, J.; Ragheb, R.; Jay, S. M.; Demento, S. L.; Agawu, A.; Licona Limon, P.; Ferrandino, A. F.; Gonzalez, D.; Habermann, A.; Flavell, R. A.; Fahmy, T. M. Combination delivery of TGF-beta inhibitor and IL-2 by nanoscale liposomal polymeric gels enhances tumour immunotherapy. Nat. Mater. 2012, 11 (10), 895−905. (45) Mandal, B.; Bhattacharjee, H.; Mittal, N.; Sah, H.; Balabathula, P.; Thoma, L. A.; Wood, G. C. Core-shell-type lipid-polymer hybrid nanoparticles as a drug delivery platform. Nanomedicine 2013, 9 (4), 474−491. (46) Al-Jamal, W. T.; Kostarelos, K. Liposomes: from a clinically established drug delivery system to a nanoparticle platform for theranostic nanomedicine. Acc. Chem. Res. 2011, 44 (10), 1094−1104. (47) Tan, S.; Li, X.; Guo, Y.; Zhang, Z. Lipid-enveloped hybrid nanoparticles for drug delivery. Nanoscale 2013, 5 (3), 860−872. (48) Zhang, J.; Gao, W.; Fang, R. H.; Dong, A.; Zhang, L. Synthesis of nanogels via cell membrane-templated polymerization. Small 2015, 11 (34), 4309−4313. (49) Zhang, Y.; Zhang, J.; Chen, W.; Angsantikul, P.; Spiekermann, K. A.; Fang, R. H.; Gao, W.; Zhang, L. Erythrocyte membrane-coated nanogel for combinatorial antivirulence and responsive antimicrobial delivery against Staphylococcus aureus infection. J. Controlled Release 2017, 263, 185−191. (50) Tang, W. L.; Chen, W. C.; Roy, A.; Undzys, E.; Li, S. D. A Simple and Improved Active Loading Method to Efficiently Encapsulate Staurosporine into Lipid-Based Nanoparticles for Enhanced Therapy of Multidrug Resistant Cancer. Pharm. Res. 2016, 33 (5), 1104−1114. (51) Haran, G.; Cohen, R.; Bar, L. K.; Barenholz, Y. Transmembrane ammonium sulfate gradients in liposomes produce efficient and stable entrapment of amphipathic weak bases. Biochim. Biophys. Acta, Biomembr. 1993, 1151, 201−215. (52) Luo, D.; Carter, K. A.; Razi, A.; Geng, J.; Shao, S.; Giraldo, D.; Sunar, U.; Ortega, J.; Lovell, J. F. Doxorubicin encapsulated in stealth liposomes conferred with light-triggered drug release. Biomaterials 2016, 75, 193−202. (53) Yingchoncharoen, P.; Kalinowski, D. S.; Richardson, D. R. Lipid-based drug delivery systems in cancer therapy: what is available and what is yet to come. Pharmacol. Rev. 2016, 68 (3), 701−787. (54) Shemesh, C. S.; Moshkelani, D.; Zhang, H. Thermosensitive liposome formulated indocyanine green for near-infrared triggered photodynamic therapy: in vivo evaluation for triple-negative breast cancer. Pharm. Res. 2015, 32 (5), 1604−1614.

(55) Zheng, M.; Zhao, P.; Luo, Z.; Gong, P.; Zheng, C.; Zhang, P.; Yue, C.; Gao, D.; Ma, Y.; Cai, L. Robust ICG theranostic nanoparticles for folate targeted cancer imaging and highly effective photothermal therapy. ACS Appl. Mater. Interfaces 2014, 6 (9), 6709−6716. (56) Zheng, M.; Yue, C.; Ma, Y.; Gong, P.; Zhao, P.; Zheng, C.; Sheng, Z.; Zhang, P.; Wang, Z.; Cai, L. Single-Step Assembly of DOX/ ICG Loaded Lipid−Polymer Nanoparticles for Highly Effective Chemo-photothermal Combination Therapy. ACS Nano 2013, 7 (3), 2056−2067. (57) Lokerse, W. J.; Kneepkens, E. C.; ten Hagen, T. L.; Eggermont, A. M.; Grull, H.; Koning, G. A. In depth study on thermosensitive liposomes: Optimizing formulations for tumor specific therapy and in vitro to in vivo relations. Biomaterials 2016, 82, 138−150. (58) Guo, F.; Yu, M.; Wang, J.; Tan, F.; Li, N. Smart IR780 theranostic nanocarrier for tumor-specific therapy: hyperthermiamediated bubble-generating and folate-targeted liposomes. ACS Appl. Mater. Interfaces 2015, 7 (37), 20556−20567. (59) Zhang, J.; Lin, X.; Liu, J.; Zhao, J.; Dong, H.; Deng, L.; Liu, J.; Dong, A. Sequential thermo-induced self-gelation and acid-triggered self-release process of drug-conjugated nanoparticles: a strategy for the sustained and controlled drug delivery to tumors. J. Mater. Chem. B 2013, 1 (36), 4667−4677.

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ICG Coencapsulated Liposome-Coated Thermosensitive

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