Research Article www.acsami.org
Biocompatible Hollow Polydopamine Nanoparticles Loaded Ionic Liquid Enhanced Tumor Microwave Thermal Ablation in Vivo Longfei Tan,† Wenting Tang,†,‡ Tianlong Liu,*,† Xiangling Ren,† Changhui Fu,† Bo Liu,*,‡ Jun Ren,† and Xianwei Meng*,† †
Laboratory of Controllable Preparation and Application of Nanomaterials, Center for Micro/Nanomaterials and Technology, Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, No. 29 East Road Zhongguancun, Beijing 100190, P. R. China ‡ School of Science, Beijing Jiaotong University, No. 3 Shangyuancun Haidian District, Beijing, 100044, P. R. China S Supporting Information *
ABSTRACT: Tumor microwave thermal therapy (MWTT) has attracted more attention because of the minimal damage to body function, convenient manipulation and low complications. Herein, a novel polydopamine (PDA) nanoparticle loading ionic liquids (ILs/PDA) as microwave susceptible agent is introduced for enhancing the selectivity and targeting of MWTT. ILs/PDA nanocomposites have an excellent microwave heating efficiency under an ultralow microwave power irradiation. Encouraging antitumor effect was observed when tumor bearing mice received ILs/PDA nanoparticles by intravenous injection and only single microwave irradiation. PDA nanoparticles with gold nanoparticles in core were constructed for tumor targeting study by ICP-MS and about 15% PDA nanoparticles were founded in tumor. Furthermore, the cytotoxicity and acute toxicity study in vivo of PDA showed the excellent biocompatibility of ILs/PDA nanocomposites. In addition, the degradation of ILs/PDA nanocomposites in simulated body fluid illustrated the low potential hazard when they entered the blood. The emergence of PDA as a novel and feasible platform for cancer thermal therapy will promote the rapid development of microwave therapy in clinics. KEYWORDS: polydopamine, ionic liquids, microwave susceptible agent, microwave thermal ablation, nanoparticle
■
INTRODUCTION Low targeting and serious side effects have become the bottleneck of the traditional therapy methods such as surgery, chemotherapy and radiotherapy.1−3 In recent decades, the development of tumor thermal ablation has shed light on novel tumor therapy treatment profit from advantages including simple, noticeably effective, side-effect-free and minimal invasiveness. However, it throws up some problems for this treatment, with uncontrollable thermal distribution may cause damages of normal tissue around the tumor and the minimally invasive operation may increase the risk of tumor metastasis and inflammation.4−6 It is highly desirable to develop a novel noninvasive thermal therapy with remarkable antitumor effect. Recently, concerns on the application of tumor microwave thermal therapy (MWTT) are being increased. The MWTT brings a ray of sunshine to cancer patients because of high thermal conversion efficiency, deep puncture, uniformed hyperthermia fields, solidification zone necrosis completely and operability.7−12 Unfortunately, though it has been accepted as an effective therapy for cancer, MWTT is still just one of the assisted methods to traditional therapy in clinics because of the reasons as mentioned above. Recently, a microwave susceptible agent based on sodium alginate microcapsules was developed, which were efficiently used © 2016 American Chemical Society
in MWTT of tumor in vivo. In the microcapsules, saline solutions were wrapped by wall materials of sodium alginate. Because of the confinement effect of the sodium alginate shell, the microcapsules exhibited ideal temperature-rise under the microwave irradiation. Moreover, excellent therapy efficiency was achieved with the tumor inhibiting ratio of 97.85% after one-time microwave irradiation with ultralow power (1.8 W/cm2, 450 MHz).13 ILs has been investigated as a promising sensitizer to MW irradiation due to their ionic character and high polarizability. In particular, the potential biomedical application of ILs, which can efficiently convert electromagnetic energy into thermal energy, have received great attention.14,15 Despite the ILs capsuled in microcapsules have been used as microwave susceptible agent in previous reports, large size of the microcapsules need intratumoral injection to reduce the indication and clinical compliance. Therefore, a novel emerged direction for cancer treatment is the nanoscale microwave susceptible agents suitable for intravenous injection with enhanced antitumor effect of MWTT. Polydopamine (PDA) is one of the most promising candidates for microwave susceptible agents because widely distribution in Received: December 17, 2015 Accepted: April 18, 2016 Published: April 18, 2016 11237
DOI: 10.1021/acsami.5b12329 ACS Appl. Mater. Interfaces 2016, 8, 11237−11245
Research Article
ACS Applied Materials & Interfaces
Fourier transform infrared spectrometry (FTIR) were obtained with the Excalibur 3100 (Varian) by using KBr. Each spectrum was recorded 4000−400 cm−1. Thermogravimetric analysis (TGA) were performed with a heating rate of 10 °C/min under N2 atmosphere and temperature ranging from 25 to 800 °C. Microwave therapy device (Beijing Hemuyu Electronics Co. Ltd.) was used to treat tumor in mice. Infrared thermal mapping instrument was used to monitor change of temperature in vivo with MWTT. Enhanced Microwave Heating in Vitro. To determine the effect of particles on microwave heating, preliminary experiment of microwave heating was performed as follow. The prepared ILs/PDA nanocomposites were dispersed in saline solution and obtained the solution concentration of 10 mg/mL. The 1 mL of ILs/PDA nanocomposites solution was added into a given small container and irradiated by different power of microwave for 5 min. The temperature values were recorded every 10 s by an optical fiber probe which was used to monitor the temperature change of ILs/PDA nanocomposites solution. The curves of temperature change with time were constructed to compare microwave efficiency intuitively. The powers of microwave changed from 0.3 to 1.8 W. Cytotoxicity Examination. HepG2 cells were used in the examination of the potential cytotoxicity of ILs/PDA nanocomposites. Cells were cultured in DMEM containing fetal bovine serum (FBS) and cultured at 37 °C in a humidifie atmosphere with 5% CO2. HepG2 cells were plated at a density of 6 × 103 cells per well in 96-well plate and cultured for 24 h. Cells were incubated for 24 h at 37 °C in a humidifie atmosphere with 5% CO2 after adding 200 μL of DMEM containing different concentrations of ILs/PDA nanocomposites. The ratios of cell-to-ILs/PDA nanocomposites were 1:0, 1:12.5, 1:25, 1:50, 1:100 and 1:200. After 24 h, the wells were washed with PBS and 20 μL of MTT (5 mg/mL) was added to each well. The cells were further incubated for 4 h at 37 °C. Then MTT was suctioned thoroughly and 150 μL of DMSO was added to per well. The absorbance of blue Formazan at 492 nm was measured. The absorbance value of 1:0 was set as 100% and the relative cell viability (%) was calculated with the equation: the absorbance value of other ratios/the absorbance value of 1:0 × 100%. Gold Content Analysis by ICP-MS. For in vivo biodistribution studies, the ICR mice bearing H22 tumor and balb/c nude mice bearing HepG-2 tumors received ILs/PDA@Au by intravenous administration were sacrificed after injection for 24 h. Heart, kidney, liver, lung, spleen and tumor were collected for ICP-MS. Wet samples were weighed, digested with nitric acid by heating and then analyzed for gold content using inductively coupled plasma Mass spectrometer (ICP-MS, NexION 300×). The percent of one given tissue was calculated by its gold concentration divide the total amounts. Tumor Microwave Thermal Ablation in Vivo. All animal experiments abided by the guidelines of the local ethics committee. ICR mice (female, 4 week old) were injected subcutaneously in the right axillary region with 0.1 mL cell suspension containing 107 H22 cells. After tumor size reached to about 100 mm3, the mice were divided into four groups randomly, including ILs/PDA, MW, ILs/PDA +MW and control, minimizing weight and tumor size differences. The mice in ILs/PDA group were injected intravenously through the tail vein with ILs/PDA nanocomposites solution (40 mg/kg) which dispersed in phosphate buffered saline (PBS). The mice in MW group were anaesthetized first with pentobarbital sodium (2 w%, 0.2 mL) and then treated with microwave irradiation at 1.8 W/cm2 for 5 min on the tumors. Two hours after intravenous injection with ILs/PDA in PBS, the mice in ILs/PDA+MW group were anaesthetized and received microwave irradiation at 1.8 W/cm2 for 5 min on the tumors. The mice in control group were treated with PBS by intravenous injection. The tumor volumes and body weights were measured and recorded every other day. The mice were sacrificed 14 days later, the main organ (hearts, livers, spleens, lungs, and kidneys) and tumors were harvested. The tumor volume value was calculated with the equation: length × width2/2. Acute Toxicity. Control group and three doses (75, 150, and 300 mg/kg) groups had been set to evaluate acute toxicity of ILs/PDA nanocomposites. Intravenous injections through the mouse tail vein at
human and other living organisms, which owns many unique and excellent properties and extensive bioapplication.16−18 First, biocompatibility of PDA has been demonstrated at the nanoscale. Lee and his co-workers investigated the toxicity of PDA nanoparticles in vivo, and found that PDA coating greatly reduced the blood toxicity and inflammatory caused by uncoated quantum dots and poly-L-lactic acid.19 Ji and his coworkers generated PDA-coated gold nanoparticles core/shell nanostructure, then showed it was biocompatible with a low cytotoxicity, and also proved it was stable in vivo which was important for biomedical application.20 Meanwhile, PDA has been used in the photothermal therapy because of its broad absorption ranging from ultraviolet to near-infrared region. Chen and his co-workers synthesized Fe3O4@PDA nanocomposites effectively kill the cancer cells with near-infrared laser.21 Lu and his co-workers synthesized simple dopamine colloidal nanospheres, which were served as photothermal therapeutic agents for the in vivo tumor therapy with intratumoral injection and the tumors of mice injected were with rather slow growth.22 However, to the best of our knowledge, PDA nanoparticles have never been reported for antitumor treatment by MWTT. Herein, hollow PDA nanoparticles loading with ionic liquids (ILs/PDA) were constructed and explored as therapeutic agents for antitumor application in vivo by MWTT. Both in vivo and in vitro experiments implied that ILs/PDA nanocomposites had favorable sensitization effect to MWTT. For in vivo distribution evaluation, PDA with gold core was synthesized and gold content was detected by ICP-MS after intravenous injection to determine the distribution of PDA indirectly. The biocompatibility was examined by cytotoxicity and acute toxicity in vivo of ILs/PDA nanocomposites.
■
EXPERIMENTAL SECTION
Materials. Dopamine hydrochloride, hematoxylin and eosin (H&E stain), and 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenytetrazolium bromide (MTT) were purchased from Sigma-Aldrich. Ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (ILs) was purchased from Shanghai Cheng Jie Chemical Co. LTD (Shanghai, China). Dimethyl sulfoxide (DMSO) was obtained from the Beijing Chemical Reagents Company. Other reagents were of analytical grade and deionized water was throughout the whole experiment process. Preparation of Hollow PDA and ILs/PDA Nanoparticles. Silica nanoparticles with or not gold core were synthesized according to our previous work.23,24 2.0 mg of template silica nanoparticles (SN) were dispersed in deionized water (24.05 mL) which contained ethanol (4.0 mL), ammonia (50.0 μL) with stirring for about 30 min. Dopamine (60.0 mg) was added into the above solution. After the mixture was stirred for 16 h at room temperature, PDA shells were formed on the SNs. Hollow PDA nanoparticles were obtained after removing silica template by HF solution (450.0 μL, 25% vol.) with shaking severely. The obtained hollow PDA nanoparticles were washed with deionized water three times by centrifugation/redispersion cycles. Hollow PDA nanoparticles (20.0 mg) were dispersed in 5.0 mL of ethanol, followed by addition of ILs (0.5 mL) which was in 1,4-dioxane (5.0 mL). The mixture was treated with ultrasound under vacuum environment for 30 min. The obtained ILs/PDA nanocomposites were washed thoroughly with ethanol and deionized water by centrifugation/ redispersion cycles. The preparation of hollow PDA@Au nanoparticles and loading of ILs are similar to hollow PDA. (See Supporting Information for details.) Characterization of Nanoparticles. Transmission electron microscope (TEM) images and scanning electron microscope (SEM) images were obtained by using a JEM-2100F TEM operated at 200 kV and a Model 4800 (Hitachi), respectively. Ultraviolet and visible spectrophotometer (UV−vis) was carried out with a JASCO UV−vis 570UV−vis spectrophotometer. The range of spectra was 200−1200 nm. 11238
DOI: 10.1021/acsami.5b12329 ACS Appl. Mater. Interfaces 2016, 8, 11237−11245
Research Article
ACS Applied Materials & Interfaces different doses of ILs/PDA nanocomposites in PBS were conducted. Mice received PBS by intravenous injection were used as control group. After injection, the symptom and mortality were recorded carefully every day. All mice were sacrificed after one month of injection and the main organs (livers, spleens, lungs, kidneys) were collected. Blood Routine Examination and Serum Biochemical Analysis. Blood was extracted for hematology analysis according to the standard collection technique. Standard hematology markers are selected for analysis:25 red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), white blood cells (WBC) and platelets (PLT). In order to separate serum, blood samples were collected via the ocular vein (about 0.8−1 mL each mouse), then centrifuged twice at 3000 rpm for 10 min. The important hepatic indicators: alanine aminotransferase
(ALT) and aspartate aminotransferase (AST) were evaluated. Nephrotoxicity was determined by blood urea nitrogen (BUN) and creatinine (CREA). These parameters were all assayed using a Biochemical Autoanalyzer (Type 7170, Hitachi, Japan). Histological Analysis. For histology, major organs of mice for acute toxicity and MWTT experiments were harvested after euthanasia. Organs were fixed in neutral buffered formalin, processed routinely into paraffin, sectioned into 5 μm thickness, and stained with hematoxylin and eosin (H&E). The slides were observed and photos were taken microscope (Olympus X71, Japan). Coefficients of Organs and Biodegradation of ILs/PDA in Vitro. The organs (hearts, livers, spleens, lungs and kidneys) of mice treated with acute toxicity experiment were excised and weighed accurately. The coefficients of hearts, livers, spleens, lungs, and kidneys to body weight were calculated as the ratio of tissues (wet weight, mg) to body weight (g). The biodegradation of ILs/PDA nanocomposites was researched in SBF for 1 month at 37 °C accompanied by a regular concussion. The initial and last samples were obtained respectively for TEM study. Statistical Analysis. Results were expressed as mean ± standard deviation (S.D). Multigroups comparisons of the means were carried out by one-way analysis of variance (ANOVA) test using SPSS 16.0 (SPSS Inc., Chicago, IL). The statistical significance for all tests was set at p < 0.05.
Scheme 1. Synthetic Scheme of ILs/PDA Nanocompositesa
■
a
The solid sphere in red represented SN, the next picture with green edge was SN/PDA core/shell nanoparticles, the green sphere represented hollow PDA nanoparticles and the sphere with green edge and many drops in it was ILs/PDA nanocomposites.
RESULTS AND DISCUSSION The ILs/PDA nanocomposites were prepared according to Scheme 1. First, monodisperse SN and SN@Au nanoparticles
Figure 1. TEM images of (a) SN, (b) SN/PDA core/shell nanoparticles, (c) hollow PDA nanoparticles and (d) ILs/PDA nanocomposites, SEM images of (e) SN, (f) SN/PDA core/shell nanoparticles, (g) hollow PDA nanoparticles and (h) ILs/PDA nanocomposites. The insets are SEM images with higher magnifications. The size distributions of (i) SN, (j) SN/PDA core/shell nanoparticles, (k) hollow PDA nanoparticles, and (l) ILs/PDA nanocomposites. 11239
DOI: 10.1021/acsami.5b12329 ACS Appl. Mater. Interfaces 2016, 8, 11237−11245
Research Article
ACS Applied Materials & Interfaces
Figure 2. UV−vis absorption spectra (a) and FT-IR spectra (b) of hollow PDA nanoparticles and ILs/PDA nanocomposites. (c) TGA of hollow PDA nanoparticles, ILs and ILs/PDA nanocomposites. The hating rate is 10 °C/min.
Figure 3. (a) Temperature elevation of ILs/PDA nanocomposites with different microwave power, from 0.3 to 1.8 W/cm2. (b) ICP-MS analysis result of gold levels in liver, spleen, lung, kidney, heart and tumor of animals intravenously injected by PDA@Au. (c) Near infrared thermal imaging of ICR mice bearing H22 tumors under microwave treatment for 5 at 1 min intervals. (*denotes statistical significance for the comparison of other organs, *p < 0.05).
a bad dispersity and morphology were observed from TEM images. Caruso and his co-workers prepared a kind of PDA capsules adopting emulsion template method.27 Generally speaking, the emulsion drops were hard to form under ordinary conditions. In the present study, SN nanoparticles were successfully applied as templates to obtain monodisperse hollow PDA nanoparticles with a controlled size. Representative TEM and SEM images of SN, SN/PDA core/ shell, hollow PDA nanoparticles and ILs/PDA nanocomposites were shown in Figure 1. All samples were spherical in shape and can be well dispersed in water. SN/PDA core/shell nanoparticles (Figure 1b, 1f) had a clearly distinguish from the uncoated SN (Figure 1a, 1e), revealing that SN was successfully coated with PDA. Moreover, the size of SN/PDA core/shell nanoparticles increased with the concentration of dopamine.
were synthesized as template materials and coated with PDA easily on the outer when dispersed in an alkaline solution under mild stirring overnight at room temperature.24 Then the SN/PDA core/shell nanoparticles were formed. Subsequently, the PDA with hollow nanostructure was obtained after selective etching silica core by HF solution. 1-butyl-3-methylimidazolium hexafluorophosphate, which is a kind of excellent heat performance material, was loaded in the hollow PDA nanoparticles through an ultrasonic method under vacuum environment. The obtained product was alternatively washed with ethanol and deionized water to remove the excess ILs. There were many kinds of methods to prepare hollow PDA particles in previous reports. For example, Ni and his co-workers fabricated polydopamine hollow capsules in a tetrahydrofuran− tris buffer mixture.26 However, the PDA hollow capsules with 11240
DOI: 10.1021/acsami.5b12329 ACS Appl. Mater. Interfaces 2016, 8, 11237−11245
Research Article
ACS Applied Materials & Interfaces
Figure 4. (a) Photographs of typical mice treated with control, only ILs/PDA, only MW and ILs/PDA together with MWTT (ILs/PDA+MW) for 0 day and 14 days. (b) Mean tumor weights in each group after excision on the 14th day. The curves of relative tumor weight (c) and tumor volumes (d) in the different treatment groups. (*denotes statistical significance for the comparison of other groups, *p < 0.05), (e) Histological sections of tumor after different treatment. The scale bar is 100 μm.
characteristic band at 1619 cm−1 was due to CC bond of indole structure in PDA.29 Compared with PDA, new typical characteristic peak at 855 cm−1 attributed to P−F group30 indicating the presence of the ILs in ILs/PDA nanocomposites. The TGA were performed to investigate the decomposition of hollow PDA nanoparticles, ILs in comparison to ILs/PDA nanocomposites (Figure 2c). There was a small loss at 90 °C, probably resulted from desorption of water and ethanol adsorbed on the PDA shell. The weight loss at 200 °C might be attributed to the decomposition of the hollow PDA nanoparticles and ILs.31 About 10−15% ILs was loaded to hollow PDA nanoparticles by comparing the curves of hollow PDA nanoparticles with ILs/PDA nanocomposites. The temperature elevation of ILs/PDA nanocomposites with different microwave irradiated powers was shown in Figure 3a. With the microwave power increasing from 0.3 to 1.8 W/cm2, it showed a rising tendency of the temperature. Furthermore, the temperature could arise to 50.6 °C at the irradiation of 1.8 W/cm2. While hollow PDA nanoparticles alone in saline had no obvious temperature elevation. Recent reports have shown that ILs have reliable thermal stabilities, strong MW absorption and can efficiently convert electromagnetic energy to thermal energy.32−34 The above results suggested that ILs has been loaded in hollow PDA nanoparticles successfully. It had been reported that cancer cells could be killed when the temperature maintained 42 °C for 15−60 min, while it could reduce that down to 4−6 min once the temperature was more
The average diameter of SN templates were about 430 nm (Figure 1i), the size of obtained SN/PDA core/shell nanoparticles were about 510 nm (Figure 1j) and the thickness of PDA shell was about 40 nm. In Figure 1c and 1g, SN nanoparticles templates had been totally removed by HF solution treatment and hollow PDA nanoparticles were formed, about 500−510 nm (Figure 1k). The TEM and SEM of ILs/PDA nanocomposites were shown in Figure 1d and 1h, respectively. The final size of ILs/PDA nanocomposites was about 510 nm (Figure 1l). The TEM image of SN@Au nanoparticles was shown in Figure S1a. The TEM image of ILs/PDA@Au was shown in the illustration of Figure S1b. The UV−vis absorption spectrum of hollow PDA nanoparticles indicated (Figure 2a) a broad band monotonic absorbance ranging from ultraviolet to infrared regions, it was supposed that the amorphous chemical disorder or heterogeneity of PDA. The strong absorption in the ultraviolet region was attributed from dopachrome and dopaindole resulted from the oxidization of dopamine.28 The weak absorption was attributed to the following self-polymerization process of dopamine. The ILs/PDA nanocomposites exhibited a similar curve to the hollow PDA nanoparticles, the reason was that the ILs have no absorption in the same scope. The FT-IR spectra of hollow PDA nanoparticles and ILs/PDA nanocomposites were carried out to analyze the presence of ILs, as shown in Figure 2b. The peaks from 3700 to 3300 cm−1 were attributed to N−H and O−H stretching modes. The 11241
DOI: 10.1021/acsami.5b12329 ACS Appl. Mater. Interfaces 2016, 8, 11237−11245
Research Article
ACS Applied Materials & Interfaces
Figure 5. Routine blood tests of ICR mice after intravenous injection with ILs/PDA nanocomposites. Mean and standard deviation of red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), white blood cells (WBC), platelets (PLT).
than 50 °C.22,35 The present results demonstrated that cancer cells could be effectively killed under the irradiation of 1.8 W/cm2 microwave power for 5 min. The strong microwave absorption capability under ultralow irradiated power makes ILs/PDA nanocomposite as a high promising agent for microwave thermal cancer therapy. For quantitative analysis the tumor targeting of ILs/PDA nanocomposite, ILs/PDA@Au was injected intravenously and gold content was detected by ICP-MS at 24 h postinjection. Three pieces of tissue were collected due to the large size of some tissues and the average value of the three pieces was considered as the final results. At 24 h postinjection, about 50% gold in lung and 15% gold in tumor were examined of animals received nanoparticles. In order to prove the high accumulation in the tumor site, besides H22 cells tumor bearing ICR mice, HepG-2 cells tumor bearing nude mice were used as tumor xenograft models (Figure S2). Au levels of different organs after PDA@Au treatment for 24 h via i.v injectiton were detected
by IPC-MS. As shown in Figure 1, at 24 h postinjection, about 30% gold in lung and 12% gold in tumor were examined. The biodistribution of gold content agreed with the data of H22 tumor mice models. In additional, photoacoustic imaging was also performed at 2 h after PDA i.v injection. Strong signals in tumor were observed under different NIR light wavelength of 680, 750, and 800 nm indicating the location of PDA to tumor region (Figure S3).These results indicated enhanced tumor targeting of PDA nanoparticles. It is well-known that nanoparticles with size above 200 nm can activate the complement system, and are rapidly cleared by the reticuloendothelial system (RES) including the liver and spleen.25,34 In contrast, red blood cells (RBCs) can easily pass through capillaries with dimensions smaller than their size and have a long circulation time in blood in part because of their deformability.36 Recent reports have shown that polymer microcapsules or hydrogel particles can behave like RBCs in biological environments.37,38 In the present study, 500 nm sized PDA hollow capsules were administered by 11242
DOI: 10.1021/acsami.5b12329 ACS Appl. Mater. Interfaces 2016, 8, 11237−11245
Research Article
ACS Applied Materials & Interfaces
Figure 6. Blood chemical indexes of ICR mice after intravenous injection with ILs/PDA nanocomposites. Mean and standard deviation of alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN) and creatinine (CREA).
To evaluate the possible cytotoxicity effect of ILs/PDA nanocomposites on HepG2 cells, a typical MTT (3-(4,5-dimethylthiazol2-yl)-2,5-diphenyltetrazolium bromide) assay was used. In Figure S5, the cell viability was hindered after adding ILs/PDA nanocomposites. The viability of HepG2 was also close to 80% when the concentration of ILs/PDA nanocomposites increased to 200 μg/mL, indicating that ILs/PDA nanocomposites have no remarkable cytotoxicity. In the acute toxicity study, the mice received ILs/PDA nanocomposites at different dosages (75, 150, 300 mg/kg). No death and abnormal behaviors were observed in all groups, including difficult breathing and moving or unusual interactions. While the dose higher than 380 mg/kg, the mice appeared passive behavior and died. The routine blood counts of RBC, HGB, HCT, MCV, MCH, MCHC, WBC and PLT (Figure 5) and biochemical indexes of ALT, AST, BUN and CREA fell in normal ranges and observed no significant changes (Figure 6). One month after administration, the organs (hearts, livers, spleens, lungs and kidneys) of mice treated with PDA were excised and weighed accurately. No obvious differences were found in the body weight of four groups. No significant difference of organs coefficients was observed of all dosages compared with control group (Figure S6a). Histological images of liver, spleen, lung and kidney at the dose of 150 mg/kg were shown in Figure 7. No obvious damages were founded in these organs. ILs/PDA nanocomposites can be founded in liver (as shown by white arrow) due to nanocomposites were swallowed by Kuffers cells after degradation. The behavior of ILs/PDA nanocomposites was researched in SBF for 1 month at 37 °C (Figure S6b). The inset TEM image showed the original pattern of ILs/PDA nanocomposites in SBF. ILs/PDA nanocomposites featured a noticeable degradation behavior in SBF after 1 month in comparison with the original ILs/PDA nanocomposites. This result indicated that ILs/PDA nanocomposites could be biodegradability.
intravenous injection could accumulate in the tumor, which should be attributed to their hollow structure deformation like that of RBCs owing to higher osmotic pressure during blood circulation. Figure 3c displayed the near-infrared thermal imaging of mice in MW and ILs+MW groups. Compared with the MW group, the temperature of the central region was rapidly increasing to above 55 °C at 2 min, the total zone of the tumor reach 55 °C under the microwave irritation for 5 min in ILs/PDA + MW group, which was enough to kill cancer cells effectively. While for the only MW group, the maximum temperature (above 55 °C) only located on the heating dots of microwave equipment and the peripheral had a slight temperature rise, indicating that uneven heating occur for MW. Photographs of mice with different treatment in 0 day and 14 day were shown in Figure 4a. The ILs/PDA+MW group could render obvious elimination of tumor volume on the 14th day, while the tumor growths of other control groups were observed clearly. The mice were sacrificed on the 14th day to get and weigh the tumors (Figure 4b). There was no obvious remnant tissue of the tumor in ILs/PDA+MW group. During the experimental process, the body weights of mice grew normally (Figure 4c). Tumors in ILs/PDA+MW group had been ablated totally at day 6 and without recurring. In MW group, tumors were slightly inhibited in the first 2 days, however, rapid increase of tumor was happened in the later 12 days. While tumors in other two groups appeared sustaining growth (Figure 4d). These results showed that the as-prepared ILs/PDA nanocomposites have noticeable antitumor effect after intravenous injection in MWTT. Histological analysis of tumor tissues received different treatment was shown in Figure 4e. Tumors of Ils/PDA+MW groups all disappears after treatment and typical histomorphology structure of tumor were observed in others groups. Histological analysis was performed to study the injury caused by ILs/PDA nanocomposites and microwave to the major organs of mice in the ILs/PDA+MW groups including liver, spleen, lung and kidney (Figure S4). No abnormal changes of the major organs like heart, liver, spleen, lung and kidney from each group were observed.
■
CONCLUSION In conclusion, hollow PDA nanoparticles loaded ILs as microwave susceptible agents were introduced for tumor thermal ablation therapy successfully. The biosafety and biodegradability 11243
DOI: 10.1021/acsami.5b12329 ACS Appl. Mater. Interfaces 2016, 8, 11237−11245
Research Article
ACS Applied Materials & Interfaces
(2) Widakowich, C.; de Castro, G.; de Azambuja, E.; Dinh, P.; Awada, A. Review: Side Effects of Approved Molecular Targeted Therapies in Solid Cancers. Oncologist 2007, 12, 1443−1455. (3) Allen, T. M. Ligand-targeted Therapeutics in Anticancer Therapy. Nat. Rev. Cancer 2002, 2, 750−763. (4) Ju, E.; Dong, K.; Liu, Z.; Pu, F.; Ren, J.; Qu, X. Tumor Microenvironment Activated Photothermal Strategy for Precisely Controlled Ablation of Solid Tumors upon NIR Irradiation. Adv. Funct. Mater. 2015, 25, 1574−1580. (5) Shieh, Y.-A.; Yang, S.-J.; Wei, M.-F.; Shieh, M.-J. Aptamer-Based Tumor-Targeted Drug Delivery for Photodynamic Therapy. ACS Nano 2010, 4, 1433−1442. (6) Cheng, L.; Wang, C.; Feng, L.; Yang, K.; Liu, Z. Functional Nanomaterials for Phototherapies of Cancer. Chem. Rev. 2014, 114, 10869−10939. (7) Du, Q.; Fu, C.; Tie, J.; Liu, T.; Li, L.; Ren, X.; Huang, Z.; Liu, H.; Tang, F.; Li, L.; Meng, X. Gelatin Microcapsules for Enhanced Microwave Tumor Hyperthermia. Nanoscale 2015, 7, 3147−3154. (8) Vogl, T. J.; Naguib, N. N. N.; Gruber-Rouh, T.; Koitka, K.; Lehnert, T.; Nour-Eldin, A. Microwave Ablation Therapy: Clinical Utility in Treatment of Pulmonary Metastases. Radiology 2011, 261, 643−651. (9) Stang, J.; Haynes, M.; Carson, P.; Moghaddam, M. A Preclinical System Prototype for Focused Microwave Thermal Therapy of the Breast. IEEE Trans. Biomed. Eng. 2012, 59, 2431−2438. (10) Sherar, M. D.; Trachtenberg, J.; Davidson, S. R. H.; Gertner, M. R. Interstitial Microwave Thermal Therapy and its Application to the Treatment of Recurrent Prostate Cancer. Int. J. Hyperthermia 2004, 20, 757−768. (11) Sherar, M. D.; Trachtenberg, J.; Davidson, S. R. H.; McCann, C.; Yue, C. K. K.; Haider, M. A.; Gertner, M. R. Interstitial Microwave Thermal Therapy for Prostate Cancer. J. Endourol 2003, 17, 617−625. (12) Sherar, M. D.; Gladman, A. S.; Davidson, S. R. H.; Trachtenberg, J.; Gertner, M. R. Helical Antenna Arrays for Interstitial Microwave Thermal Therapy for Prostate Cancer: Tissue Phantom Testing and Simulations for Treatment. Phys. Med. Biol. 2001, 46, 1905−1918. (13) Shi, H.; Liu, T.; Fu, C.; Li, L.; Tan, L.; Wang, J.; Ren, X.; Ren, J.; Wang, J.; Meng, X. Insights into a Microwave Susceptible Agent for Minimally Invasive Microwave Tumor Thermal Therapy. Biomaterials 2015, 44, 91−102. (14) Shi, H.; Niu, M.; Tan, L.; Liu, T.; Shao, H.; Fu, C.; Ren, X.; Ma, T.; Ren, J.; Li, L.; Liu, H.; Xu, K.; Wang, J.; Tang, F.; Meng, X. A Smart All-in-one Theranostic Platform for CT Imaging Guided Tumor Microwave Thermotherapy Based on IL@ZrO2 Nanoparticles. Chem. Sci. 2015, 6, 5016−5026. (15) Du, Q.; Ma, T.; Fu, C.; Liu, T.; Huang, Z.; Ren, J.; Shao, H.; Xu, K.; Tang, F.; Meng, X. Encapsulating Ionic Liquid and Fe3O4 Nanoparticles in Gelatin Microcapsules as Microwave Susceptible Agent for MR Imaging Guided Tumor Thermotherapy. ACS Appl. Mater. Interfaces 2015, 7, 13612−13619. (16) Liu, Y.; Ai, K.; Lu, L. Polydopamine and Its Derivative Materials Synthesis and Promising Applications in Energy, Environmental, and Biomedical Fields. Chem. Rev. 2014, 114, 5057−5115. (17) Waite, J. H. Mussel Power. Nat. Mater. 2008, 7, 8−9. (18) Zhang, L.; Wu, J.; Wang, Y.; Long, Y.; Zhao, N.; Xu, J. Combination of Bioinspiration: A General Route to Superhydrophobic Particles. J. Am. Chem. Soc. 2012, 134, 9879−9881. (19) Nurunnabi, M.; Khatun, Z.; Nafiujjaman, M.; Lee, D.; Lee, Y. Surface Coating of Graphene Quantum Dots Using Mussel-Inspired Polydopamine for Biomedical Optical Imaging. ACS Appl. Mater. Interfaces 2013, 5, 8246−8253. (20) Liu, X.; Cao, J.; Li, H.; Li, J.; Jin, Q.; Ren, K.; Ji, J. MusselInspired Polydopamine: A Biocompatible and Ultrastable Coating for Nanoparticles. ACS Nano 2013, 7, 9384−9395. (21) Lin, L.-S.; Cong, Z.-X.; Cao, J.-B.; Ke, K.-M.; Peng, Q.-L.; Gao, J.; Yang, H.-H.; Liu, G.; Chen, X. Multifunctional Fe3O4@Polydopamine Core−Shell Nanocomposites for Intracellular mRNA Detection
Figure 7. Histological sections of liver (A), spleen (B), lung (C) and kidney (D) of animals received PDA by intravenous injection at 150 mg/kg dosage. PDA nanoparticles can be found in Kuffers cells exist in liver, as shown by white arrow. The scale bar is 100 μm.
of ILs/PDA nanocomposites have been demonstrated. However, for further clinical application, the study of biodistribution of ILs/PDA nanocomposites in vivo and long-term toxicity are needed. In depth investigating of the deformability behavior and targeting ability will be carried out in the future. For microwave systems, such as frequency, conversion efficiency between electromagnetic energy and thermal energy also need to be investigated
■
ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsami.5b12329. Histological sections images, cytotoxicity results and the degradation TEM image of ILs/PDA nanocomposites in SBF for 1 month (PDF)
■
AUTHOR INFORMATION
Corresponding Authors
*E-mail:
[email protected]. Tel: (+86)10-82543521. Fax: (+86)10-82543521. *E-mail:
[email protected]. Tel: (+86)10-51688409. *E-mail:
[email protected]. Tel: (+86)10-82543521. Fax: (+86)10-82543521. Notes
The authors declare no competing financial interest.
■
ACKNOWLEDGMENTS The authors acknowledge financial support from the National Hi-Technology Research and Development Program (863 Program) (No. 2012AA022701 and 2013AA032201), Beijing Natural Science Foundation (No. 4161003) and the National Natural Science Foundation of China (NSFC) (No. 81201814, 51202260 and 31400854).
■
REFERENCES
(1) Misra, R.; Acharya, S.; Sahoo, S. K. Cancer Nanotechnology: Application of Nanotechnology in Cancer Therapy. Drug Discovery Today 2010, 15, 842−50. 11244
DOI: 10.1021/acsami.5b12329 ACS Appl. Mater. Interfaces 2016, 8, 11237−11245
Research Article
ACS Applied Materials & Interfaces and Imaging-Guided Photothermal Therapy. ACS Nano 2014, 8, 3876−3883. (22) Liu, Y.; Ai, K.; Liu, J.; Deng, M.; He, Y.; Lu, L. DopamineMelanin Colloidal Nanospheres An Efficient Near-Infrared Photothermal Therapeutic Agent for In Vivo Cancer Therapy. Adv. Mater. 2013, 25, 1353−1359. (23) Chen, D.; Li, L.; Tang, F.; Qi, S. Facile and Scalable Synthesis of Tailored Silica Nanorattle Structures. Adv. Mater. 2009, 21, 3804− 3807. (24) Tan, L.; Chen, D.; Liu, H.; Tang, F. A Silica Nanorattle with a Mesoporous Shell: An Ideal Nanoreactor for the Preparation of Tunable Gold Cores. Adv. Mater. 2010, 22, 4885−4889. (25) Liu, T.; Li, L.; Teng, X.; Huang, X.; Liu, H.; Chen, D.; Ren, J.; He, J.; Tang, F. Single and Repeated Dose Toxicity of Mesoporous Hollow Silica Nanoparticles in Intravenously Exposed Mice. Biomaterials 2011, 32, 1657−1668. (26) Ni, Y.-Z.; Jiang, W.-F.; Tong, G.-S.; Chen, J.-X.; Wang, J.; Li, H.M.; Yu, C.-Y.; Huang, X.-H.; Zhou, Y.-F. Preparation of Polydopamine Nanocapsules in a Miscible Tetrahydrofuran−Buffer Mixture. Org. Biomol. Chem. 2015, 13, 686−690. (27) Cui, J.; Wang, Y.; Postma, A.; Hao, J.; Hosta-Rigau, L.; Caruso, F. Monodisperse Polymer Capsules: Tailoring Size, Shell Thickness, and Hydrophobic Cargo Loading via Emulsion Templating. Adv. Funct. Mater. 2010, 20, 1625−1631. (28) Xu, H.; Liu, X.; Wang, D. Interfacial Basicity-Guided Formation of Polydopamine Hollow Capsules in Pristine O/W Emulsions Toward Understanding of Emulsion Template Roles. Chem. Mater. 2011, 23, 5105−5110. (29) Yu, X.; Fan, H.; Liu, Y.; Shi, Z.; Jin, Z. Characterization of Carbonized Polydopamine Nanoparticles Suggests Ordered Supramolecular Structure of Polydopamine. Langmuir 2014, 30, 5497− 5505. (30) Song, S.-W.; Baek, S.-W. Surface Layer Formation on Sn Anode: ATR FTIR Spectroscopic Characterization. Electrochim. Acta 2009, 54, 1312−1318. (31) Weiss, E.; Dutta, B.; Kirschning, A.; Abu-Reziq, R. BMIm-PF6@ SiO2 Microcapsules Particulated Ionic Liquid as A New Material for the Heterogenization of Catalysts. Chem. Mater. 2014, 26, 4781−4787. (32) Gao, H.; Xing, J.; Xiong, X.; Li, Y.; Li, W.; Liu, Q.; Wu, Y.; Liu, H. Immobilization of Ionic Liquid [BMIM][PF6] by Spraying Suspension Dispersion Method. Ind. Eng. Chem. Res. 2008, 47, 4414−4417. (33) Zhu, Y.; Chen, F. Microwave-assisted Preparation of Inorganic Nanostructures in Liquid Phase. Chem. Rev. 2014, 114, 6462−555. (34) Liu, H.; Chen, D.; Li, L.; Liu, T.; Tan, L.; Wu, X.; Tang, F. Multifunctional Gold Nanoshells on Silica Nanorattles: a Platform for the Combination of Photothermal Therapy and Chemotherapy with Low Systemic Toxicity. Angew. Chem. 2011, 123, 921−925. (35) Habash, R. W. Y.; Bansal, R.; Krewski, D.; Alhafid, H. T. Thermal Therapy, Part 1: An Introduction to Thermal Therapy. Crit. Rev. Biomed. Eng. 2006, 34, 459. (36) Diez-Silva, M.; Dao, M.; Han, J. Y.; Lim, C. T.; Suresh, S. Shape and Biomechanical Characteristics of Human Red Blood Cells in Health and Disease. MRS Bull. 2010, 35, 382−388. (37) Shao, J.; Xuan, M.; Dai, L.; Si, T.; Li, J.; He, Q. Near-InfraredActivated Nanocalorifiers in Microcapsules: Vapor Bubble Generation for In Vivo Enhanced Cancer Therapy. Angew. Chem., Int. Ed. 2015, 54, 12782−12787. (38) Munoz Javier, A.; Kreft, O.; Semmling, M.; Kempter, S.; Skirtach, A. G.; Bruns, O. T.; del Pino, P.; Bedard, M. F.; Rädler, J.; Käs, J.; Plank, C.; Sukhorukov, G. B.; Parak, W. J. Uptake of Colloidal Polyelectrolyte-Coated Particles and Polyelectrolyte Multilayer Capsules by Living Cells. Adv. Mater. 2008, 20, 4281−4287.
11245
DOI: 10.1021/acsami.5b12329 ACS Appl. Mater. Interfaces 2016, 8, 11237−11245
