pH and Glutathione Dual-Responsive Dynamic ... - ACS Publications

Subscriber access provided by University of Pennsylvania Libraries

Article

pH and Glutathione Dual-Responsive Dynamic CrossLinked Supramolecular Network on Mesoporous Silica Nanoparticles for Controlled Anticancer Drug Release Qing-Lan Li, Shi-Han Xu, Hang Zhou, Xin Wang, Biao Dong, Hui Gao, Jun Tang, and Ying-Wei Yang ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.5b10534 • Publication Date (Web): 03 Dec 2015 Downloaded from http://pubs.acs.org on December 9, 2015

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

ACS Applied Materials & Interfaces is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

pH and Glutathione Dual-Responsive Dynamic Cross-Linked Supramolecular Network on Mesoporous Silica Nanoparticles for Controlled Anticancer Drug Release Qing-Lan Li,† Shi-Han Xu,§ Hang Zhou,† Xin Wang,† Biao Dong,§ Hui Gao,*,‡ Jun Tang,*,† Ying-Wei Yang*,† †

College of Chemistry, International Joint Research Laboratory of Nano-Micro Architecture

Chemistry (NMAC), State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, and §State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China. ‡

School of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Organic Solar Cells

and Photochemical Conversion, School of Material Science and Engineering, Tianjin University of Technology, Tianjin 300384, P. R. China.

KEYWORDS: mesoporous silica nanoparticles, cucurbit[7]uril, poly(glycidyl methacrylate)s, controlled release, pH, glutathione, doxorubicin hydrochloride

1 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ABSTRACT: Dynamic cross-linked supramolecular network of poly(glycidyl methacrylate)s derivative chains was constructed on mesoporous silica nanoparticles via disulfide bond and iondipole interactions between cucurbit[7]urils and protonated diamines in the polymer chains. This kind of multifunctional organic-inorganic hybrid material with pH- and glutathione- (GSH-) stimuli responsiveness can be applied to anti-cancer drug delivery and controlled release. Good release performance towards doxorubicin hydrochloride (DOX) was achieved under the simulative tumor intracellular environment (pH = 5.0, CGSH = 2~10 mM). Significantly, the release amount of DOX increased upon lowering the solution pH value and increasing the concentration of GSH, as demonstrated by a series of controlled release experiments. Furthermore, the DOX-loaded hybrid nanomaterials displayed apparent cell-growth inhibition effects to cancer cell lines, as evidenced by MTT assay and confocal laser scanning microscopy.

INTRODUCTION With the development of materials science and synthetic chemistry, a variety of stimuliresponsive controlled drug delivery systems (CDDS) have been designed to improve the efficacy of conventional chemotherapy and reduce its side effects.1-3 In the past decades, organic– inorganic hybrid nanoparticles,4,5 supramolecular nanoparticles,6 and liposomes7 have been employed as nanocontainers to construct CDDS. As is well known, mesoporous silica nanoparticles (MSNs) with large specific surface area, good biocompatibility, suitable pore diameter and particle size, are ideal candidates as nanocontainers for controlled drug release.8,9 Meanwhile, the silicon hydroxyl groups on MSNs are active and easy to be functionalized, making it possible to prepare more novel stimuli-responsive hybrid materials based on MSNs.10,11 For example, Fe3O412 and CdS13 nanoparticles functionalized MSNs with redox


Page 2 of 28

Page 3 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


stimuli-responsiveness were reported by Lin et al.; and Zink, Stoddart and our group have developed a series of supramolecular nanovalves2-5,9 base on macrocyclic synthetic receptors (cucurbiturils (CBs),14-16 cyclodextrins (CDs),17,18 calixarenes,19-21 and pillararenes22) and MSNs for controlled drug release. Meanwhile, the intersection of materials science and polymer chemistry provides fresh ideas for the design of hybrid materials. A pH- and salt- sensitive CDDS reported by Shi and coworkers utilized PAH/PSS multilayers on hollow MSNs as a coating to prevent loaded drugs from leaking.23 Feng et al. constructed a redox-responsive polymer network on poly(Nacryloxysuccinimide) (PNAS)-grafted MSNs via the cross-linking of PNAS chains by adding cystamine.24 Then, they further introduced β-CD and guest molecules into PNAS-grafted MSNs to form a supramolecular polymer network with multiple stimuli-responsiveness.25 The pHresponsive nanovalve systems consisted of polyethyleneimine(PEI)/CD polypseudorotaxanes and MSNs were also designed for drug release by Kim et al.17 There is no doubt that the joint of polymeric materials and supramolecular macrocyclic synthetic receptors endows MSNs more excellent performance, which is a feasible route to prepare new functional hybrid materials for CDDS and other possible applications. Poly(glycidyl methacrylate)s (PGMAs) have been applied in many research fields, ascribed to its straightforward synthesis, good biocompatibility and easy chemical modification.26-29 For example, various cationic PGMA derivatives prepared via ring opening reaction by amines were used as carriers for anionic biomolecules, especially pDNA.28,29 And, we have been also devoting ourselves to the fabrication of novel hybrid materials for controlled drug release by combining PGMA derivatives and MSNs.30-32 Azobenzene-functionalized MSNs coated by β-CD-modified PGMA via host-guest interactions exhibited UV stimuli-responsiveness and better efficiency for controlled drug release compared



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

with those being coated by individual β-CDs.30 Meanwhile, layer-by-layer alternant assemblies of EDA-PGOHMA and CB[7] rings on MSNs via ion-dipole interactions realized pH sensitive disassembly followed by further application as smart anticancer drug nanocarriers.31 In order to meet the different needs of drug release at certain lesion locations, it is necessary to study CDDS with different stimuli-responsiveness (light,33-35 pH,21,36-38 enzymes,18,19 temperature,39,40 redox,41-45 competitive agents,20 etc.). For example, we reported acetylcholine (ACh)-triggered calixarene and pillarene-based supramolecular nanovalves for site-specific drug release on account of the higher concentration of ACh in the synapses of Parkinson’s disease patients compared with normal people.20 A series of hybrid materials prepared for controlled drug release at tumor location were always pH or GSH stimulusresponsive because of its aberrant tumor intracellular environment compared with normal tissues, such as acidic pH levels of endosome and lysosome (5.0-5.5), high level glutathione (GSH) concentration (2~10 mM), and oxidative microenvironment in mitochondria due to high concentration of H2O2.44-46 Importantly, the design of a smart hybrid material which can be operated simultaneously by pH and GSH, is still meaningful for improving the curative effect and reducing the side effects of cancer chemotherapy. As protonated ethanediamine (EDA) forms 2:1 host-guest complex with CB[7] through cation-dipole interaction,47 we employed PGMA chains ring-opened by EDA and CB[7]s to build dynamic cross-linked network with pH sensitivity on MSN surfaces.31 Meanwhile, disulfide bonds between PGMA chains and MSNs endowed the hybrid material GSH-responsiveness. The drug release performances of the hybrid material in different in vitro environments and its cell-growth inhibition assay for A549 cells after loading with DOX were also discussed in detail in this paper.


Page 4 of 28

Page 5 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


EXPERIMENTAL SECTION Materials.

Most

of

the

chemicals

and

reagents

used

herein,

such

as

(3-

mercaptopropyl)trimethoxysilane, tetraethoxysilane (TEOS), 2,2'-dipyridyl disulfide and dicyclohexylcarbodiimide (DCC), were of analytical grade and purchased from Aladdin, China. Cetyltrimethyl ammonium bromide (CTAB) was purchased from Sinopharm, Glutathione (GSH) from J&K Scientific Ltd, and DOX from Beijing Huafeng United Technology Co. Ltd. A series of phosphate buffers (PBS) were prepared according to the Chinese Pharmacopeia (Second Part, 2010 Edition). CB[7] was synthesized according to the method reported by Day et al.48 2Hydroxyethyl 2-bromoisobutyrate and PGMAs with hydroxyl groups at the chain ends were prepared according to the literature with some modifications.49-51 Measurements. Nuclear magnetic resonance (NMR) spectra were recorded on a Varian 300 MHz NMR spectrometer. Molecular weight and polydispersity were measured on gel permeation chromatography (GPC, equipped with a Waters e2695 HPLC pump, a Waters 2414 differential refractive detector and PSS columns, linear polystyrene standards were used for calibration.), employing tetrahydrofunan (THF) as mobile phase at 35 °C with flow rate of 1 mL/min. Powder X-ray diffraction (PXRD) patterns were collected on a Rigaku Ultima IV powder diffractometer. Fourier transform infrared spectra (FT-IR) were measured using a Vertex 80V spectrometer. Zeta potentials of materials were measured via Zetasizer Nano ZS. Nitrogen adsorption and desorption measurements were perform on a Micromeritics Gemini. Meanwhile, BrunauerEmmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) models were chosen to calculate the surface area and pore diameter. Thermogravimetric analysis (TGA) was operated on TA Q500 with 10 K / min heating rate in N2 atmosphere. The different morphology of materials was observed via scanning electron microscopy (SEM) on a JEOL JSM 6700F instrument and 5 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

transmission electron microscopy (TEM) on Hitachi H-800 that was operated with an accelerating voltage of 200 kV. Controlled release processes were monitored on a Shimadzu UV1800 spectrophotometer. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were carried out on a microplate reader (Bio-tek, Elx800) and confocal laser scanning microscopy (CLSM) images were collected on a confocal fluorescence microscope (FV1000, Olympus). Preparation of Bare Silica Nanoparticles (MSN-OH): CTAB (1.0 g), H2O (480 mL) and 2 M NaOH (aq, 3.5 mL) were added into a 1 L round-bottom flask. And the mixture was stirred at 80 °C for 30 min to form the corresponding template. Then TEOS (5.0 mL) was added rapidly and the solution was stirred vigorously at 80 °C for 2 h. The resulting white precipitate was obtained via filtration and drying. In order to get ordered mesoporous channels, the extraction method with acid methanol solution was applied to remove the template. The as-synthesized white material (1.0 g) was added into methanol (100 mL) solution mixed with concentrated HCl (1 mL) beforehand. The reaction solution was refluxed for 6 h at 60 °C. After filtration and drying, silica nanoparticles with mesopores (MSN-OH) were obtained and then characterized by SEM, FT-IR, XRD, BET and BJH. Preparation of Sulfhydryl Groups Functionalized Silica Nanoparticles (MSN-SH)52: A dispersed suspension of synthesized MSN-OH (0.4 g) in anhydrous toluene (100 mL) was heated at 60 °C under nitrogen atmosphere. 3-Mercaptopropyltrimethoxysilane (1.0 mL) was added and then the reaction solution was stirred at 60 °C for 20 h. After filtration, the resulting solid product was washed with anhydrous toluene and methanol, and dried in vacuum oven at room temperature overnight. MSN-SH was characterized by FT-IR, TGA and Raman spectroscopy.


Page 6 of 28

Page 7 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Synthesis of Mechanized MSNs with Disulfide Bonds (MSN-SS-COOH): (1) Synthesis of 2-carboxyethyl 2-pyridyl disulfide: 2-Carboxyethyl 2-pyridyl disulfide was prepared according to the literature report.53 2,2'-Dipyridyl disulfide (1.5 g) and acetic acid (0.16 mL) were added into anhydrous ethanol (6 mL). When 2,2'-dipyridyl disulfide was dissolved completely, 3-mercaptopropionic acid (0.3 mL) was added, followed by stirring at room temperature for 2 days. After rotary evaporation to remove solvents, the residue was purified by column chromatography (eluent: n-hexane / CH2Cl2 / MeOH = 70: 35: 2) to yield a white solid. (2) 2-Carboxyethyl 2-pyridyl disulfide functionalized MSNs: MSN-SH (0.4 g) was dispersed in anhydrous ethanol (25 mL) containing the synthesized 2-carboxyethyl 2-pyridyl disulfide (0.24 g). Then, acetic acid (0.8 mL) was added to the solution, and the solution was stirred at room temperature for 48 h under nitrogen atmosphere. The resulting product was obtained after washing with ethanol and drying under vacuum at room temperature for 24 h, denoted as MSNSS-COOH. Grafting PGMA onto Silica Nanoparticles via Covalent Bond: (1) Synthesis of PGMA with hydroxyl at the chain end (PGMA-OH): The DMF solution (4 mL) containing CuBr2 (2.4 mg), N,N,N’,N’’,N’’-Pentamethyldiethylenetriamine (PMDTA, 13.6 µL) and GMA (1 mL) was stirred and purged with N2 for 30 min. Then ascorbic acid and 2hydroxyethyl 2-bromoisobutyrate were added, respectively, to activate the reaction. After the mixture was stirred at 50 °C for another 4 h, raw product precipitated out in cool diethyl ether and was further purified by neutral alumina column. The structure and average molecular weight of the final product were characterized by 1H NMR and GPC. (2) PGMA-OH chains grafted on MSNs by forming ester bonds: After PGMA-OH (300 mg) was dissolved in dry THF (120 mL), MSN-SS-COOH (300 mg), catalytic amount of DCC and



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

DMAP were added. Then the mixture was stirred at room temperature under nitrogen atmosphere for 3 days. The solid, marked as MSN-SS-PGMA, was isolated by centrifugation, washed with THF, and dried under vacuum at room temperature. MSN-SS-PGMA was again dispersed in THF (40 mL), followed by addition of ethylenediamine (EDA, 2.6 mL). The resulting solution was refluxed for 24 h under nitrogen atmosphere, centrifuged and washed with THF and ethanol to obtain the final material, denoted as MSN-SS-(EDA-PGOHMA). DOX Loading and Dynamic Supramolecular Cross-Linking of Polymer Chains via CB[7]s: Diffusion effect and concentration gradient were employed to load anticancer drug (doxorubicin hydrochloride, DOX) in the nanopores of the materials. The synthesized MSN-SS-(EDAPGOHMA) materials (60 mg) were dispersed in an aqueous solution of DOX (2 mM, 24 mL), and then the suspension solution was stirred for 24 h. For further formation of dynamic linking structure towards polymer chains on the surfaces of MSNs, 60 mg of CB[7]s were added and the mixture was stirred for another 24 h. Finally, the corresponding products were obtained via centrifugation and denoted as MSNs@DOX@CB[7]. The equation of drug loading capacity was calculated as follows: Loading capacity (wt %) =

୑ୟୱୱ ୭୤ ୪୭ୟୢୣୢ ୢ୰୳୥ ୑ୟୱୱ ୭୤ ୪୭ୟୢୣୢ ୬ୟ୬୭୮ୟ୰୲୧ୡ୪ୣୱ

× 100%

DOX Release activated by pH changes and GSH addition: In order to systematically study the controlled release performance of materials at different acidic pHs, MSNs@DOX@CB[7] (1 mg) was added in centrifuge tubes with 2 mL PBS (0.2 M, pH = 7.4, 5.0, 4.0, 3.0 and 2.0, respectively). Then the tubes were put in a constant temperature vibrator and the temperature was maintained at 37 °C. At specific time intervals, the supernatant containing released DOX was taken out for ultraviolet spectral analysis at 481 nm. Meanwhile, according to the weakly acidic and high level of GSH in tumor intracellular environment, different concentrations of 8 ACS Paragon Plus Environment

Page 8 of 28

Page 9 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


GSH (0, 2, 5, 10 and 20 mM, respectively) in PBS (pH = 5.0) were also chosen to explore the dependence of drug release amount on GSH concentrations. Cell culture: A549 cells were bought from Shanghai Institute for Biological sciences, Chinese Academy of Science. They were incubated with the culture medium containing RPMI 1640 (90%) and fetal bovine serum (10%) under 37 °C and 5% CO2 conditions. Trypsin with 0.02% EDTA was utilized to re-suspend cells. Cell viability assays: Cell viability was evaluated by using a methyl-thiazolyltetrazolium (MTT) method. Firstly, A549 cells were seeded onto 96-well plates at a density of 5×103/well. After 24 h, as A549 cells attached to the plates, they were incubated with different concentrations of DOX, MSN-SS-PGOHMA (MSNs) and MSNs@DOX@CB[7] for 24 h. Then MTT solution (10 µL, 1 mg/mL) was added into each well, and cells were further incubated for 4 h. After that, the culture medium in 96 wells was discarded through using a micro-syringe and dimethylsulfoxide (DMSO, 150 µL) was added into each well. The absorbance intensity was determined at 490 nm by a microplate reader (Bio-tek, Elx800). Results were presented as the % survival with respect to untreated control cells. Cell imaging of A549 cells: CLSM was employed to further monitor the therapeutic effects of our newly synthesized materials. At first, A549 cells were seeded on 35 mm confocal dishes and incubated for 24 h, then they were treated with MSNs@DOX@CB[7] in fresh medium. After different time intervals, 4, 12, and 24 h, A549 cells were stained with propidium iodide (PI) and Hoechst 33342 for 10 min. After that, PBS was utilized to wash dishes three times to remove extra dyes, and then imaged under CLSM. 488 nm lasers were chosen to excite DOX and PI, with yellow channel monitoring the scale from 520 to 580 nm for DOX and red channel



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 28

monitoring the scale from 600 to 660 nm for PI. 405 nm lasers were applied for Hoechst 33342 and the blue channel detects the emission of Hoechst 33342 ranged between 425 nm and 475 nm. RESULTS AND DISCUSSION Syntheses and Characterization of Mechanized MSNs. The synthetic route of PGMA-SS(EDA-PGOHMA) and its supramolecular assembly with CB[7] macrocycles were shown in Scheme 1. MSNs of spherical shape (Figure 1) were synthesized via the base-catalyzed sol-gel method. The mesoporous structure of MSN-OH was confirmed by the type IV curve of N2 adsorption and desorption isotherm (Fig. S4), with the assistance of TEM (Figure 1c). The specific surface and average pore size were 902 m2/g and 2.56 nm, respectively, as calculated by the Brunauer-Emmett-Teller (BET) model and the Barrett-Joyner-Halenda (BJH) method. Characteristic diffraction peaks at 100, 110, 200 and 210 in Figure 2A indicate that the synthesized MSN-OH belongs to MCM-41 type with highly ordered 2D hexagonal pore channel array. After a series of functionalization, the 2D hexagonal pore channel array was still maintained, but its regularity degree inevitably reduced, inferred from the strong diffraction peak at 100 and three disappeared peaks in Figure 2A(b). As shown in Figure 1 and Fig. S5, MSN-OH displayed spherical shape and its average diameter was around 68 ± 8.7 nm as calculated via statistics analysis of particle size distribution. After surface functionalization with 3mercaptopropyltrimethoxysilane, 2-carboxyethyl 2-pyridyl disulfide and PGMA-OH step by step, the average diameter of target particles increased to 84.5 ± 12.9 nm. Except for blurry mesoporous structures, the legible polymer layer coating on MSNs can also be observed in the TEM image of MSN-SS-(EDA-PGMAOH) and its thickness is about 7 nm. Increasing of the diameters of MSNs and polymer layer observed visually demonstrated the successful graft of PGMA-OH chains on MSNs. 10 ACS Paragon Plus Environment

Page 11 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Scheme 1. Schematic diagram of (a) the pH and GSH dual-responsive dynamic cross-linked supramolecular network on MSNs; (b) the synthetic route of MSN-SS-(EDA-PGOHMA) and its assembly with CB[7]. FT-IR spectroscopy was employed to direct the progress of MSN surface functionalization (Figure 2C). The strong absorption signals at around 1086 cm-1 in all the spectra of MSN-based materials belong to the stretching and asymmetric stretching of Si-O-Si bonds. Compared with the spectrum of MSN-SH, after modification with 2-carboxyethyl 2pyridyl disulfide, the new peaks at 3434 cm-1, 2966 cm-1 and 1725 cm-1 assigned to the stretching vibration of –OH, -CH2 and C=O, respectively, can be observed, indirectly indicating the



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 12 of 28

Figure 1. Scanning electron microscopy (SEM) images of (a) MSN-OH and (b) MSN-SS-(EDAPGOHMA); Transmission electron microscopy (TEM) images of (c) MSN-OH and (d) MSNSS-(EDA-PGOHMA). formation of disulfide bonds. The peak of MSN-SS-PGMA slightly shifted from 1725 cm-1 to 1732 cm-1 when PGMA was grafted on MSN-SS-COOH via ester bonds. After ring-opening reaction of PGMA with EDA, the stretching vibration band of N-H at 3297 cm-1 was displayed. Because the stretching vibration band of S-H on MSN-SH was too weak to be observed via FTIR spectroscopy, the existence of -SH was demonstrated by the Raman signal at 2580 cm-1 and no SH group was detected after conjugation with 2-carboxyethyl 2-pyridyl disulfide (Figure 2B). The surface functionalization extent of MSNs was characterized by TGA analysis (Figure 2D) and the final weight losses for all materials are presented in Table S1. Increasing weight losses indicated the successful immobilization of 3-mercaptopropyltrimethoxysilane, 2-carboxyethyl 2pyridyl disulfide and PGMA on MSNs. There is about 0.815 mmol/g carboxyl on MSN-SS12 ACS Paragon Plus Environment

Page 13 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


COOH as calculated from extra 8.57 % weight loss after being modified by 2-carboxyethyl 2pyridyl disulfide. 0.0175 mmol/g of PGMA-OH is grafted on MSN-SS-COOH via ester bond confirmed by its average mean molecular weight (5120 g/mol) and excess 12.77 % of weight loss. In addition, the average surface potentials of MSNs were shown in Table S2. These materials can be steadily dispersed in water and their zeta potentials changed from -23.0 mV to

Figure 2. (A) Powder small-angle X-ray diffraction (PXRD) patterns of (a) MSN-OH and (b) MSN-SS-(EDA-PGOHMA); (B) Raman spectra of (a) MSN-SH and (b) MSN-SS-COOH; (C) FT-IR spectra of MSN-OH (black), MSN-SH (red), MSN-SS-COOH (blue), MSN-SS-PGMA (green), MSN-SS-(EDA-PGOHMA) (pink) and PGMA-OH (yellow). (D) TGA curves of MSNOH (black), MSN-SH (red), MSN-SS-COOH (blue) and MSN-SS-(EDA-PGOHMA) (green).



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 14 of 28

+30.4 mV along with modification of MSNs. Meanwhile, the final MSNs@DOX@CB[7] with positive charged surface (+24.9 mV) is apt to be swallowed by cells via electrostatic interactions with the negatively charged cell surfaces.54 pH- and GSH- Responsive Drug Release. The anticancer drug DOX was chosen as a model drug to study the stimuli-responsive release performance of our materials. There was ca. 1.4 wt % of DOX loaded in the mesopores of MSN-SS-(EDA-PGOHMA) nanoparticles as calculated by loading experiments. And the drug loading capacity was raised to 6.3 wt % after CB[7] addition, due to the formation of the compact cross-linked polymer layer on MSNs through EDAPGOHMA polymer chains and CB[7]s, which can effectively avoid the leakage of DOX in the process of cargo loading. As we know, protonated EDAs in EDA-PGOHMA chains can form 2:1 host-guest complexes with CB[7] through cation-dipole interaction.31 Therefore, CB[7]s can be employed as molecular bridges linking two neighboring polymer chains to build a dynamic supramolecular polymer cross-linked network on MSNs. Compared with other general cross-linked structures of polymers formed via covalent bonds, this supramolecular polymer cross-linked network is flexible and its compactness can be regulated by the changes of external environment. In order to systematically study the pH-responsive performance of the designed dynamic cross-linked supramolecular network on MSNs, the drug release curves of MSNs@DOX@CB[7] in PBS solutions with different pH values (pH = 7.4, 5.0, 4.0, 3.0 and 2.0, respectively) were traced by UV-vis spectra (Figure 3A). At physiological environment (pH = 7.4), EDAPGOHMA polymer chains grafted on MSNs have been tightly linked together by CB[7]s and became a dense supramolecular polymer cross-linked network, effectively avoiding the drug leakage and reducing the side effects of anticancer drugs, which was demonstrated by the limited


Page 15 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


DOX release from MSNs at pH of 7.4. Upon lowering the pH value, the concentration of hydronium ions increased and its competitive binding ability with CB[7] strengthened, resulting in the partial disassembly of the cross-linked supramolecular network. At pH = 5.0, the disassembly of cross-linked supramolecular network was too weak and slow to permit drug release. While when the pH of the solution was lowered to 4.0, some CB[7]s escaped from the cross-linked network and bind with hydronium ions instead of original EDA-PGOHMA, leading

Figure 3. Release curves of MSNs@DOX@CB[7] (0.5 mg/mL) (A) only in PBS solutions with different pH values, (B) adding GSH (10 mM) into different pH valued PBS solutions, and (C) changing GSH concentrations in pH = 5.0 solution; (D) The GSH concentration-dependent drug releases capacity in pH = 5.0 solution after 7 h. 15 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 16 of 28

to the disassembly of cross-linked network and 28.6% of drug release. Upon further reducing the pH value to 3.0 and 2.0, more CB[7] molecules were competitively robbing away from the crosslinked network by excessive hydronium ions and the cross-linked network further disassembled more thoroughly, resulting in a rapid release of DOX from the mesopores of MSNs. In addition to the pH stimulus-responsive ability, the cross-linked network can be also activated by GSH owning to its redox ability towards disulfide bonds in polymer chains. After adding the same amount of GSH (10 mM) into PBS solution with different pH values (e.g., pH = 7.4, 5.0, and 3.0), the release curves of DOX changed accordingly (Figure 3B). No significant acceleration of drug release was observed upon addition of GSH at pH = 7.4, mostly because the tightly cross-linked network prevents GSH molecules from entering the inner region of polymer layer to move polymer chains by cutting the disulfide bonds. However, when the pH value was lowered to 5.0, the cross-linked supramolecular network became loosened and GSH could enter the interior of polymer layer and plays an effective role. As a result, the total DOX release reaches to 6.0 × 10-2 mg per 1 mg materials, about two times quantity of that under no GSH condition. At pH = 3.0, excessive hydronium ions make the cross-linked network disassemble thoroughly, so DOX molecules could freely escape from MSNs and its release quantity is not affected by the added GSH. However, the drug release reached a plateau only within 3 h after adding GSH, indicating that the drug release rate has been increased obviously. As is well known, pH value and GSH concentration in tumor intracellular environment are 5.0-5.5 and 2-10 mM, respectively, which are deviated from the normal level (pH = 7.4, CGSH = 2-20 uM). So the designed pH and GSH stimuli-responsive hybrid material is an ideal candidate as anti-cancer drug carriers. The influence of GSH concentration on drug release at pH = 5.0 was also studied and their positive correlation relationship was presented in Figure 3C and


Page 17 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


3D. Higher concentrations of GSH result in higher degrees of cleavage towards polymer chains, and fewer obstacles make DOX run away from MSNs more easily. According to the standard curve of DOX measured by UV-vis spectrophotometer, there are 0.92-6.8 × 10-2 mg DOX released from per 1 mg materials when they are motivated by 0-20 mM GSH at pH = 5.0. The cytotoxicity of MSNs to A549 cells and its therapeutic efficiency after loading with DOX were investigated by MTT assay (Figure 4). The results showed that cell viabilities kept higher than 93%, even though the concentration of MSNs was as high as 40 µg/mL, indicating MSNs itself has negligible cytotoxicity to A549 cells. Meanwhile, good cell-growth inhibition

Figure 4. In vitro cell-growth inhibition assay for A549 cells after adding DOX (red), MSNs@DOX@CB[7] (blue), and MSNs (black) with corresponding concentrations (0, 2.5, 5, 10, 20, 40 µg/mL) which can load the same amount of DOX (0, 0.15, 0.31, 0.63, 1.25, 2.5 µg/mL). effect was presented when DOX was loaded in MSNs and the cell viability was only 35% at DOX concentration of 2.5 µg/mL. Moreover, cell-growth inhibition rate of MSNs@DOX@CB[7] 17 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 18 of 28

toward cancer cells was in the range of 0-1.25 µg/mL, and the fact that A549 cells treated with MSNs@DOX@CB[7] have higher cell viability is reasonable, because it takes some time for drug release from MSNs. In general, the cancer cell-growth inhibition effect of MSNs@DOX@CB[7] at 0.63-2.5 µg/mL is optimistic and it is hopeful to use this organicinorganic hybrid material as anti-cancer drug nanocarriers. The therapeutic effects of DOX loaded in hybrid materials were further investigated by confocal microscope in real time. After different incubation times (4, 12 and 24 h, respectively) with MSNs@DOX@CB[7], cells were washed with PBS for three times to remove extra materials in nutrient solution. Hoechst 33342 was used to stain the nucleus, and PI could easily penetrate membranes of dead cells and emit bright red light, so it was used to stain and label dead cells. As shown in Figure 5, most of DOX could enter the nucleus at the first 4 h, while the cells still remain alive which was inferred from no emission signal of PI detected in Figure 5 e1. When cells were treated with materials for 12 h, the red emission light of PI could be observed in Figure 5 e2, predicting that the membrane of cells was partly broken and they went to apoptosis. Almost all cells were dead after being cultivated with materials for 24 h (Figure 5 e3). In addition, morphology changes of A549 cells could be notably observed through images of bright field (Figure 5 a1, a2, and a3) and vividly display the dead process of cells, demonstrating good therapeutic effects of MSNs@DOX@CB[7] on A549 cells.


Page 19 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 5. CLSM-images of A549 cells incubated with MSNs@DOX@CB[7] for 4 h (1), 12 h (2) and 24 (3). Images from left to right are: the cells with bright field (a), with nucleus stained with Hoechst 33342 (b, blue channel), with DOX (c, yellow channel), an overlay of b-c (d) and dead cells stained with PI (e, red channel) in each row. Bar = 100 µm

CONCLUSION In conclusion, the dynamic cross-linked supramolecular network employed as a pH and GSH dual stimuli-responsive nanovalve, was constructed on MSNs via covalent bonds and host-guest interactions between CB[7]s and EDA-PGOHMAs. The disassembly of the cross-linked polymer network by lowering the pH value was the key and indispensable factor to result in drug release. Meanwhile, addition of GSH could remove polymer chains via the cleavage of disulfide bonds and efficiently promote drug release at certain pH value. So little premature release at normal physiological environment was realized and undesired drug side-effects can be effectively 19 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 20 of 28

decreased through using the prepared material to load drugs. At the same time, good drug release performance of MSNs@DOX@CB[7] was displayed at simulated tumor intracellular environment (pH = 5.0, CGSH = 2-10 mM), suggesting that this material is an ideal candidate as anti-cancer drug carriers. In addition, in vitro cell-growth inhibition assay and CLSM experiments about the hybrid material for A549 cells proved, after loading DOX, it has very good inhibitory effect on cancer cell growth by triggering its death. All in all, the designed hybrid material is a smart nano-vessel for controlled anticancer drug release, and this new supramolecular approach may pave a new avenue in the construction of novel organic-inorganic hybrid materials for cancer therapy. ASSOCIATED CONTENT Supporting Information Some experimental data including NMR, GPC, N2 adsorption, SEM, particle size distribution, TGA, and Zeta potential. The Supporting Information is available free of charge on the ACS Publications website at DOI: . AUTHOR INFORMATION Corresponding Authors *E-mail: [email protected] (Y.W.Y.) *Email: [email protected] (H.G.) *E-mail: [email protected] (J.T.) ACKNOWLEDGEMENTS


Page 21 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


We thank the National Natural Science Foundation of China (51473061), the Fundamental Research Funds for the Central Universities (JCKY-QKJC05), and the JLU Cultivation Fund for the National Science Fund for Distinguished Young Scholars for financial support. These authors declare no competing financial interest.

REFERENCES (1) Mura, S.; Nicolas, J.; Couvreur, P. Stimuli-Responsive Nanocarriers for Drug Delivery. Nat. Mater. 2013, 12, 991–1003. (2) Song, N.; Yang, Y.-W. Molecular and Supramolecular Switches on Mesoporous Silica Nanoparticles. Chem. Soc. Rev. 2015, 44, 3474–3504. (3) Yang, Y.-W. Towards Biocompatible Nanovalves based on Mesoporous Silica Nanoparticles. Med. Chem. Commun. 2011, 2, 1033–1049. (4) Ambrogio, M. W.; Thomas, C. R.; Zhao, Y.-L.; Zink, J. I.; Stoddart, J. F. Mechanized Silica Nanoparticles: A New Frontier in Theranostic Nanomedicine. Acc. Chem. Res. 2011, 44, 903– 913. (5) Yang, Y.-W.; Sun, Y.-L.; Song, N. Switchable Host-Guest Systems on Surfaces. Acc. Chem. Res. 2014, 47, 1950–1960. (6) Zhao, Y.; Duan, S.; Yu, B.; Liu, F.-S.; Cheng, G.; Xu, F.-J. Gd(III) Ion-Chelated Supramolecular Assemblies Composed of PGMA-Based Polycations for Effective Biomedical Applications, NPG Asia Mater. 2015, 7, e197. (7) Zhu, L.; Kate, P.; Torchilin, V. P. Matrix Metalloprotease 2-Responsive Multifunctional Liposomal Nanocarrier for Enhanced Tumor Targeting. ACS Nano 2012, 6, 3491–3498. (8) Slowing, I. I.; Trewyn, B. G.; Giri, S.; Lin, V. Y. Mesoporous Silica Nanoparticles for Drug Delivery and Biosensing Applications. Adv. Funct. Mater. 2007, 17, 1225–1236. 21 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 22 of 28

(9) Li, Z.; Barnes, J. C.; Bosoy, A.; Stoddart, J. F.; Zink, J. I. Mesoporous Silica Nanoparticles in Biomedical Applications. Chem. Soc. Rev. 2012, 41, 2590–2605. (10) Lim, M. H.; Stein, A. Comparative Studies of Grafting and Direct Syntheses of Inorganic– Organic Hybrid Mesoporous Materials. Chem. Mater. 1999, 11, 3285–3295. (11) Huh, S.; Wiench, J. W.; Yoo, J.-C.; Pruski, M.; Lin, V. S. Y. Organic Functionalization and Morphology Control of Mesoporous Silicas via a co-Condensation Synthesis Method. Chem. Mater. 2003, 15, 4247–4256. (12) Giri, S.; Trewyn, B. G.; Stellmaker, M. P.; Lin, V. S.-Y. Stimuli-Responsive ControlledRelease Delivery System Based on Mesoporous Silica Nanorods Capped with Magnetic Nanoparticles. Angew. Chem., Int. Ed. 2005, 44, 5038–5044. (13) Lai, C.-Y.; Trewyn, B. G.; Jeftinija, D. M.; Jeftinija, K.; Xu, S.; Jeftinija, S.; Lin, V. S.-Y. A Mesoporous Silica Nanosphere-Based Carrier System with Chemically Removable CdS Nanoparticle Caps for Stimuli-Responsive Controlled Release of Neurotransmitters and Drug Molecules. J. Am. Chem. Soc. 2003, 125, 4451–4459. (14) Angelos, S.; Yang, Y.-W.; Khashab, N. M.; Stoddart J. F.; Zink, J. I. Dual-Controlled Nanoparticles Exhibiting AND Logic. J. Am. Chem. Soc. 2009, 131, 11344–11346. (15) Angelos, S.; Yang, Y.-W.; Patel, K.; Stoddart J. F.; Zink, J. I. pH Clock-Operated Mechanized Nanoparticles. Angew. Chem., Int. Ed. 2008, 47, 2222–2226. (16) Sun, Y.-L.; Yang, B.-J.; Zhang, S. X.-A.; Yang, Y.-W. Cucurbit[7]uril PseudorotaxaneBased Photo-Responsive Supramolecular Nanovalve. Chem. Eur. J. 2012, 18, 9212–9216. (17) Park, C.; Oh, K.; Lee, S. C.; Kim, C. Controlled Release of Guest Molecules from Mesoporous Silica Particles Based on a pH-Responsive Polypseudorotaxane Motif. Angew. Chem., Int. Ed. 2007, 46, 1455–1457.


Page 23 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(18) Patel, K.; Angelos, S.; Dichtel, W. R.; Coskun, A.; Yang, Y.-W.; Zink J. I.; Stoddart, J. F. Enzyme-Responsive Snap-Top Covered Silica Nanocontainers. J. Am. Chem. Soc. 2008, 130, 2382–2383. (19) Sun, Y.-L.; Zhou, Y.; Li, Q.-L.; Yang, Y.-W. Enzyme-Responsive Supramolecular Nanovalves Crafted by Mesoporous Silica Nanoparticles and Choline-Sulfonatocalix[4]arene [2]Pseudorotaxanes for Controlled Cargo Release. Chem. Commun. 2013, 49, 9033–9035. (20) Zhou, Y.; Tan, L.-L.; Li, Q.-L.; Qiu, X.-L.; Qi, A.-D.; Tao, Y.; Yang, Y.-W. AcetylcholineTriggered Cargo Release from Supramolecular Nanovalves based on Different Macrocyclic Receptors. Chem. Eur. J. 2014, 20, 2998–3004. (21) Li, H.; Tan, L.-L.; Jia, P.; Li, Q.-L.; Sun, Y.-L.; Zhang, J.; Ning, Y.-Q.; Yu, J.; Yang, Y.-W. Near-Infrared Light-Responsive Supramolecular Nanovalve based on Mesoporous Silica-Coated Gold Nanorods. Chem. Sci. 2014, 5, 2804–2808. (22) Sun, Y.-L.; Yang, Y.-W.; Chen, D.-X.; Wang, G.; Zhou, Y.; Wang, C.-Y.; Stoddart, J. F. Mechanized Silica Nanoparticles Based on Pillar[5]arenes for on-Command Cargo Release. Small 2013, 9, 3224–3229. (23) Zhu, Y.; Shi, J.; Shen, W.; Dong, X.; Feng, J.; Ruan, M.; Li, Y. Stimuli-Responsive Controlled Drug Release from a Hollow Mesoporous Silica Sphere/Polyelectrolyte Multilayer Core–Shell Structure. Angew. Chem. Int. Ed. 2005, 117, 5213–5217. (24) Liu, R.; Zhao, X.; Wu, T.; Feng, P. Tunable Redox-Responsive Hybrid Nanogated Ensembles. J. Am. Chem. Soc. 2008, 130, 14418–14419. (25) Liu, R.; Zhang, Y.; Feng, P. Multiresponsive Supramolecular Nanogated Ensembles. J. Am. Chem. Soc. 2009, 131, 15128–15129.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 28

(26) Li, Q.-L.; Gu, W.; Gao, H.; Yang, Y.-W. Self-Assembly and Applications of Poly(Glycidyl Methacrylate)s and Their Derivatives. Chem. Commun. 2014, 50, 13201–13215. (27) Sun, Y.; Sun, Y.-L. Wang, L.; Ma, J.; Yang, Y.-W.; Gao, H. Nanoassembles Constructed from Mesoporous Silica Nanoparticles and Surface-Coated Multilayer Polyelectrolytes for Controlled Drug Delivery. Microporous Mesoporous Mater. 2014, 185, 245–253. (28) Yang, X.-C.; Niu, Y.-L.; Zhao, N.-N.; Mao, C.; Xu, F.-J. A Biocleavable Pullulan-Based Vector via ATRP for Liver Cell-Targeting Gene Delivery. Biomaterials 2014, 35, 3873–3884. (29) Li, R. Q.; Niu, Y. L.; Zhao, N. N.; Yu, B. R.; Mao C.; Xu, F. J. Series of New βCyclodextrin-Cored Starlike Carriers for Gene Delivery. ACS Appl. Mater. Interfaces 2014, 6, 3969–3978. (30) Li, Q.-L.; Wang, L.-Z.; Qiu, X.-L.; Sun, Y.-L.; Wang, P.-X.; Liu, Y.; Li, F.; Qi, A.-D.; Gao, H.; Yang, Y.-W. Stimuli-Responsive Biocompatible Nanovalve Based on β-Cyclodextrin Modified Poly(Glycidyl Methacrylate). Polym. Chem. 2014, 5, 3389–3395. (31) Li, Q.-L.; Sun, Y.; Sun, Y.-L.; Wen, J.; Zhou, Y.; Bing, Q.; Isaacs, L.; Jin, Y.; Gao, H.; Yang, Y.-W. Mesoporous Silica Nanoparticles Coated by Layer-by-Layer Self-Assembly Using Cucurbit[7]uril for in vitro and in vivo Anticancer Drug Release. Chem. Mater. 2014, 26, 6418– 6431. (32) Wu, Y.; Long, Y.; Li, Q.-L.; Han, S.; Ma, J.; Yang, Y.-W.; Gao, H. Layer-by-Layer (LBL) Self-Assembled Biohybrid Nanomaterials for Efficient Antibacterial Applications. ACS Appl. Mater. Interfaces 2015, 7, 17255−17263. (33) Mal, N. K.; Fujiwara, M.; Tanaka, Y. Photocontrolled Reversible Release of Guest Molecules from Coumarin-Modified Mesoporous Silica. Nature 2003, 421, 350–353.


Page 25 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(34) Ferris, D. P.; Zhao, Y.-L.; Khashab, N. M.; Khatib, H. A.; Stoddart, J. F.; Zink, J. I. LightOperated Mechanized Nanoparticles. J. Am. Chem. Soc. 2009, 131, 1686–1688. (35) Guardado-Alvarez, T. M.; Devi, L. S.; Russell, M. M.; Schwartz, B. J.; Zink, J. I. Activation of Snap-Top Capped Mesoporous Silica Nanocontainers Using Two Near-Infrared Photons. J. Am. Chem. Soc. 2013, 135, 14000−14003. (36) Gan, Q.; Lu, X.; Dong, W.; Yuan, Y.; Qian, J.; Li, Y.; Shi J.; Liu, C. Endosomal pHActivatable Magnetic Nanoparticle-Capped Mesoporous Silica for Intracellular Controlled Release. J. Mater. Chem. 2012, 22, 15960–15968. (37) Wang, M.; Chen, T.; Ding, C.; Fu, J. Mechanized Silica Nanoparticles Based on Reversible Bistable [2]Pseudorotaxanes as Supramolecular Nanovalves for Multistage pH-Controlled Release. Chem. Commun. 2014, 50, 5068–5071. (38) Chen, T.; Yang, N.; Fu, J. Controlled Release of Cargo Molecules from Hollow Mesoporous Silica Nanoparticles Based on Acid and Base Dual-Responsive Cucurbit[7]uril Pseudorotaxanes. Chem. Commun. 2013, 49, 6555–6557. (39) Fu, Q.; Rama Rao, G. V.; Ward, T. L.; Lu, Y.; Lopez, G. P. Thermoresponsive Transport through Ordered Mesoporous Silica/PNIPAAm Copolymer Membranes and Microspheres. Langmuir 2007, 23, 170–174. (40) Wu, X.; Wang, Z.; Zhu, D.; Zong, S.; Yang, L.; Zhong, Y.; Cui, Y. pH and Thermo DualStimuli-Responsive Drug Carrier Based on Mesoporous Silica Nanoparticles Encapsulated in a Copolymer–Lipid Bilayer. ACS Appl. Mater. Interfaces 2013, 5, 10895–10903. (41) Luo, Z.; Cai, K.; Hu, Y.; Li, J.; Ding, X.; Zhang, B.; Xu, D.; Yang, W.; Liu, P. RedoxResponsive Molecular Nanoreservoirs for Controlled Intracellular Anticancer Drug Delivery Based on Magnetic Nanoparticles. Adv. Mater. 2012, 24, 431–435.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 26 of 28

(42) Luo, Z.; Hu, Y.; Cai, K.; Ding, X.; Zhang, Q.; Li, M.; Ma, X.; Zhang, B.; Zeng, Y.; Li, P.; Li, J.; Liu, J.; Zhao, Y. Intracellular Redox-Activated Anticancer Drug Delivery by Functionalized Hollow Mesoporous Silica Nanoreservoirs with Tumor Specificity. Biomaterials 2014, 35, 7951–7962. (43) Luo, Z.; Cai, K.; Hu, Y.; Zhao, L.; Liu, P.; Duan, L.; Yang, W. Mesoporous Silica Nanoparticles End-Capped with Collagen: Redox-Responsive Nanoreservoirs for Targeted Drug Delivery. Angew. Chem. Int. Ed. 2011, 50, 640–643. (44) Zhou, T.; Song, N.; Xu, S.-H.; Dong, B.; Yang, Y.-W. Dual-Responsive Mechanized Mesoporous Silica Nanoparticles Based on Sulfonatocalixarene Supramolecular Switches. ChemPhysChem 2015, DOI: 10.1002/cphc.201500726. (45) Xiao, D.; Jia, H. Z.; Zhang, J.; Liu, C. W.; Zhuo, R. X.; Zhang, X. Z. A Dual-Responsive Mesoporous Silica Nanoparticle for Tumor-Triggered Targeting Drug Delivery. Small 2014, 10, 591–598. (46) Bai, L.; Wang, X. H.; Song, F.; Wang, X. L.; Wang, Y. Z. “AND” Logic Gate Regulated pH and Reduction Dual-Responsive Prodrug Nanoparticles for Efficient Intracellular Anticancer Drug Delivery. Chem. Commun. 2014, 51, 93–96. (47) Lagona, J.; Mukhopadhyay, P.; Chakrabarti, S.; Isaacs, L. The Cucurbit[n]uril Family. Angew. Chem. Int. Ed. 2005, 44, 4844–4870. (48) Day, A.; Arnold, A. P.; Blanch, R. J.; Snushall, B. Controlling Factors in the Synthesis of Cucurbituril and Its Homologues. J. Org. Chem. 2001, 66, 8094−8100. (49) Jakubowski, W.; Lutz, J. F.; Slomkowski, S.; Matyjaszewski, K. Block and Random Copolymers as Surfactants for Dispersion Polymerization. I. Synthesis via Atom Transfer


Page 27 of 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Radical Polymerization and Ring-Opening Polymerization. J Polym Sci Part A: Polym Chem. 2005, 43, 1498–1510. (50) Gao, H.; Lu, X.; Ma, Y.; Yang, Y.-W.; Li, J.; Wu, G.; Wang, Y.; Fan, Y.; Ma, J. Amino Poly(Glycerol Methacrylate)s for Oligonucleic Acid Delivery with Enhanced Transfection Efficiency and Low Cytotoxicity. Soft Matter 2011, 4, 9239–9247. (51) Gu, W.-X.; Zhu, M.; Song, N.; Du, X.; Yang, Y.-W.; Gao, H. Reverse Micelles Based on Biocompatible β-Cyclodextrin Conjugated Polyethylene Glycol Block Polylactide for Protein Delivery. J. Mater. Chem. B 2015, 3, 316–322. (52) Luo, Z.; Ding, X.; Hu, Y.; Wu, S.; Xiang,Y.; Zeng, Y.; Zhang, B.; Yan, H.; Zhang, H.; Zhu, L.; Liu, J.; Li, J.; Cai, K.; Zhao, Y. Engineering a Hollow Nanocontainer Platform with Multifunctional Molecular Machines for Tumor-Targeted Therapy in Vitro and in Vivo. ACS Nano, 2013, 7, 10271–10284. (53) Jung, J.; Solanki, A.; Memoli, K. A.; Kamei, K.-i.; Kim, H.; Drahl, M. A.; Williams, L. J.; Tseng, H.-R.; Lee, K. Selective Inhibition of Human Brain Tumor Cells through Multifunctional Quantum-Dot-Based siRNA Delivery. Angew. Chem., Int. Ed. 2010, 49, 103–107. (54) Mahmoudi, M.; Azadmanesh, K.; Shokrgozar, M. A.; Journeay, W. S.; Laurent, S. Effect of Nanoparticles on the Cell Life Cycle. Chem. Rev. 2011, 111, 3407–3432. (55) He, C.; Hu, Y.; Yin, L.; Tang, C.; Yin, C.; Effects of Particle Size and Surface Charge on Cellular Uptake and Biodistribution of Polymeric Nanoparticles. Biomaterials 2010, 31, 3657– 3666. (56) Frohlich, E.; The Role of Surface Charge in Cellular Uptake and Cytotoxicity of Medical Nanoparticles. Int. J. Nanomedicine 2012, 7, 5577–5591.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Page 28 of 28

pH and Glutathione Dual-Responsive Dynamic ... - ACS Publications

Recommend Documents