Zhi Yong Qian

Biodegradable in situ gel‐forming controlled drug delivery system based on thermosensitive PCL–PEG–PCL hydrogel: Part 1—synthesis, characterization, and acute toxicity evaluation

In this work, biodegradable PCL-PEG-PCL (PCEC) triblock copolymers were successfully synthesized at one-step. Aqueous solution of PCEC copolymer displayed thermosensitive sol-gel-sol transition behavior, which is flowing sol at low temperature and turns into non-flowing gel at body temperature. The cytotoxicity of PCEC copolymer was evaluated by cell viability assay using HEK293 and WISH cells. In vivo gel-formation, degradation test, acute toxicity tests, and histopathological study of PCEC hydrogels were performed in BALB/c mice by subcutaneous administration. In acute toxicity test, the mice were observed continuously for 21 days. For histopathologic study, samples including heart, liver, spleen, lung, kidneys, and tissue of injection site were histochemical prepared and stained with hematoxylin-eosin. No mortality or significant signs of acute toxicity was observed during the whole observation period and there is no significant lesion to be shown in histopathologic study of major organs and tissue of injection site. The maximum tolerance dose (MTD) of PCEC hydrogel (20 wt%) by subcutaneous administration was calculated to be higher than 25 g/kg b.w. The results indicated that the obtained PCEC hydrogel was non-toxic after subcutaneous administration, and could be a safe candidate for in situ gel-forming controlled drug delivery system.

Thermosensitive PEG–PCL–PEG hydrogel controlled drug delivery system: Sol–gel–sol transition and in vitro drug release study

In this article, biodegradable and low molecular weight poly(ethylene glycol)-poly(epsilon-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE) triblock copolymers were successfully synthesized. Aqueous solution of the obtained PECE copolymers underwent sol-gel-sol transition as temperature increased which was flowing sol at room temperature and then turned into nonflowing gel at body temperature. Sol-gel-sol phase transition behaviors of aqueous PECE solutions were studied using rheometry and test tube-inverting method, which were affected by many factors, including the heating/cooling procedure and different additives in copolymers aqueous solution. In vitro drug release behavior was studied using bovine serum albumin (BSA) and Vitamin B(12) (VB(12)) as model drugs, and the PECE hydrogel could protect BSA from acidic degradation for 1 week at least. Therefore, PECE hydrogel is believed to be promising for injectable in situ gel-forming controlled drug delivery system due to their great thermosensitivity and biodegradability.

In vitro drug release behavior from a novel thermosensitive composite hydrogel based on Pluronic f127 and poly(ethylene glycol)-poly(ε-caprolactone)-poly(ethylene glycol) copolymer

BackgroundMost conventional methods for delivering chemotherapeutic agents fail to achieve therapeutic concentrations of drugs, despite reaching toxic systemic levels. Novel controlled drug delivery systems are designed to deliver drugs at predetermined rates for predefined periods at the target organ and overcome the shortcomings of conventional drug formulations therefore could diminish the side effects and improve the life quality of the patients. Thus, a suitable controlled drug delivery system is extremely important for chemotherapy.ResultsA novel biodegradable thermosensitive composite hydrogel, based on poly(ethylene glycol)-poly(ε-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE) and Pluronic F127 copolymer, was successfully prepared in this work, which underwent thermosensitive sol-gel-sol transition. And it was flowing sol at ambient temperature but became non-flowing gel at body temperature. By varying the composition, sol-gel-sol transition and in vitro drug release behavior of the composite hydrogel could be adjusted. Cytotoxicity of the composite hydrogel was conducted by cell viability assay using human HEK293 cells. The 293 cell viability of composite hydrogel copolymers were yet higher than 71.4%, even when the input copolymers were 500 μg per well. Vitamin B12 (VB12), honokiol (HK), and bovine serum albumin (BSA) were used as model drugs to investigate the in vitro release behavior of hydrophilic small molecular drug, hydrophobic small molecular drug, and protein drug from the composite hydrogel respectively. All the above-mentioned drugs in this work could be released slowly from composite hydrogel in an extended period. Chemical composition of composite hydrogel, initial drug loading, and hydrogel concentration substantially affected the drug release behavior. The higher Pluronic F127 content, lower initial drug loading amount, or lower hydrogel concentration resulted in higher cumulative release rate.ConclusionThe results showed that composite hydrogel prepared in this paper were biocompatible with low cell cytotoxicity, and the drugs in this work could be released slowly from composite hydrogel in an extended period, which suggested that the composite hydrogel might have great potential applications in biomedical fields.

Acute toxicity evaluation of biodegradable in situ gel-forming controlled drug delivery system based on thermosensitive PEG-PCL-PEG hydrogel

In this work, a biodegradable poly(ethylene glycol)-poly(epsilon-caprolactone)-poly (ethylene glycol) (PEG-PCL-PEG, PECE) triblock copolymer was successfully synthesized. The aqueous solution of such PECE copolymer displayed special sol-gel-sol transition as temperature increase, which is a flowing sol at low-temperature and turns into a nonflowing gel at body temperature. The cytotoxicity of PECE copolymer was evaluated by cell viability assay using HEK 293 cells. In vivo gel formation and degradation test based on intraperitoneal and subcutaneous administration was conducted, respectively. The acute toxicity test and histopathological study were performed in BALB/c mice by intrapleural, intraperitoneal, or subcutaneous administration of PECE hydrogel (30 Wt %), respectively. The dose of intrapleural, intraperitoneal, or subcutaneous administration was up to 10 g/kg body weight (b.w.), 25 g/kg b.w., and 25 g/kg b.w., respectively, and the mice were observed continuously for 14 days. For histopathologic study, samples including heart, liver, lung, kidneys, spleen, stomach, intestine, and tissue of injection site were prepared for histochemical analysis and were stained with hematoxylin-eosin. No mortality or significant signs of acute toxicity was observed during the whole observation period and there is no significant lesion to be shown in histopathologic study of major organs. Therefore, the maximum tolerance dose of PECE hydrogel by intrapleural, intraperitoneal, or subcutaneous administration was calculated to be higher than 10 g/kg b.w., 25 g/kg b.w., and 25 g/kg b.w., respectively. The results indicated that the prepared PECE hydrogel was nontoxic after intrapleural, intraperitoneal, or subcutaneous administration, and it could be a safe candidate for in situ gel-forming controlled drug delivery system.

Preparation and properties of nano-hydroxyapatite/PCL-PEG-PCL composite membranes for tissue engineering applications

Nano-hydroxyapatite (n-HA)/poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL, PCEC) composite membranes were prepared by solvent casting and evaporation method. The structure and properties of the membranes were investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), water contact angle measurements, in vitro hydrolytic degradation, mechanical test, and cell culture. The effect of n-HA content on physical-chemical properties of the n-HA/PCEC composite membranes was studied. The results showed that the shape and size of micropores of the composite membranes changed with n-HA content increased; the tensile strength decreased with the increase of n-HA content. The osteoblast cell was cultured on the membranes, good cell attachment and growth manner were observed after postseeding for 1 day. MTT assays showed that the n-HA/PCEC membranes had no negative effect on the cell viability and proliferation. These results suggested that the obtained n-HA/PCEC composite membranes in this study might have prospective applications in tissue engineering field.

Identification of ATP synthase beta subunit (ATPB) on the cell surface as a non-small cell lung cancer (NSCLC) associated antigen

BackgroundAntibody-based immuneotherapy has achieved some success for cancer. But the main problem is that only a few tumor-associated antigens or therapeutic targets have been known to us so far. It is essential to identify more immunogenic antigens (especially cellular membrane markers) for tumor diagnosis and therapy.MethodsThe membrane proteins of lung adenocarcinoma cell line A549 were used to immunize the BALB/c mice. A monoclonal antibody 4E7 (McAb4E7) was produced with hybridoma technique. MTT cell proliferation assay was carried out to evaluate the inhibitory effect of McAb4E7 on A549 cells. Flow cytometric assay, immunohistochemistry, western blot and proteomic technologies based on 2-DE and mass spectrometry were employed to detect and identify the corresponding antigen of McAb4E7.ResultsThe monoclonal antibody 4E7 (McAb4E7) specific against A549 cells was produced, which exhibited inhibitory effect on the proliferation of A549 cells. By the proteomic technologies, we identified that ATP synthase beta subunit (ATPB) was the corresponding antigen of McAb4E7. Then, flow cytometric analysis demonstrated the localization of the targeting antigen of McAb4E7 was on the A549 cells surface. Furthermore, immunohistochemstry showed that the antigen of McAb4E7 mainly aberrantly expressed in tumor cellular membrane in non-small cell lung cancer (NSCLC), but not in small cell lung cancer (SCLC). The rate of ectopic expressed ATPB in the cellular membrane in lung adenocarcinoma, squamous carcinoma and their adjacent nontumourous lung tissues was 71.88%, 66.67% and 25.81% respectively.ConclusionIn the present study, we identified that the ectopic ATPB in tumor cellular membrane was the non-small cell lung cancer (NSCLC) associated antigen. ATPB may be a potential biomarker and therapeutic target for the immunotherapy of NSCLC.

Preparation, characterization, and optimization of pancreas-targeted 5-Fu loaded magnetic bovine serum albumin microspheres.

The magnetic bovine serum albumin (BSA) microspheres (MS) were prepared by emulsification/solidification method. In this experiment, two kinds of magnetic MS, e.g. BSA MS and PEG-incorporated BSA microspheres (PMS) were prepared. The obtained MS were characterized by Malvern laser particle sizer and scanning electron microscopy (SEM). The obtained MS were spherical and about 1.3 μm in size. The magnetic responsivity and in vitro release behavior of these MS were studied in detail. The in vivo distribution and targeting delivery of 5-fluorouracil (5-Fu) magnetic MS after artery administration were studied in rat. The results showed that PMS could efficiently delivery 5-Fu to the targeted site compared with BSA MS without PEG MS and free drug.

Nanoparticle-delivered quercetin for cancer therapy.

Quercetin, a natural protective bioflavonoid, possesses diverse pharmacologic effects, such as antioxidant, anti-inflammatory, anti-proliferative, and anti-angiogenic activities. Recently, quercetins effect in cancer prevention and treatment was recognized. However, the poor water solubility and low-bioavailability of quercetin limit its clinical use in cancer therapy. Nanotechnology provides a method to create novel formulations for hydrophobic drug. Nanoparticles-delivered quercetin has attracted many attentions for its enhanced anticancer potential and promising clinical application. This review will discuss the application of nanotechnology in quercetin delivery for cancer therapy.

Synthesis and properties of a novel biodegradable poly(ester amine) copolymer based on poly(L-lactide) and low molecular weight polyethylenimine for gene delivery

Background Gene therapy is a promising approach to the treatment of a wide range of diseases. The development of efficient and adequate gene delivery systems could be one of the most important factors. Polyethyleneimine, a cationic polymer, is one of the most successful and widely used vectors for nonviral transfection in vitro and in vivo. Methods A novel biodegradable poly(ester amine) copolymer (PEA) was successfully prepared from low molecular weight polyethylenimine (PEI, 2000 Da) and poly(L-lactide) copolymers. Results According to the results of agarose gel electrophoresis, particle size and zeta potential measurement, and transfection efficiency, the PEA copolymers showed a good ability to condense plasmid DNA effectively into nanocomplexes with a small particle size (≤150 nm) and moderate zeta potential (≥10 mV) at an appropriate polymeric carrier/DNA weight ratio. Compared with high molecular weight PEI (25kDa), the PEA obtained showed relatively high gene transfection efficiency as well as low cytotoxicity in vitro. Conclusion These results indicate that such PEA might have potential application as a gene delivery system.

Preparation and characterization of microporous poly(d,l-lactic acid) film for tissue engineering scaffold

We prepared a series of microporous films based on poly(d,l-lactic acid) (PLA) via phase separation. According to scanning electron microscopy (SEM), a 3-dimensional foamy structure with multimicrometer scale pores on the air surface of film could be observed. As the morphology of PLA film could not be stabilized using solvent–nonsolvent phase separation, we investigated the effect of temperature, air movement, and concentration on the properties of microporous PLA films. The results show that when the temperature was 25°C in a vacuum, it was easy to prepare PLA film with micropores, and it was stable. As the relationship between the morphology and formation factors was clear and the morphology of the PLA film was controllable, we studied the PLA film’s potential use for cell culture. SEM results showed that NIH3T3 cell could be adhered on the surface of film well after incubation for 2 days. Meanwhile, in vitro culture experiments revealed the great biocompatibility of the scaffold for adsorption and proliferation of fibroblasts.