A novel drug and gene co-delivery system based on Poly(epsilon-caprolactone)-Poly(ethylene glycol)-Poly(epsilon-caprolactone) grafted polyethyleneimine micelle.

In this paper, we prepared a novel cationic self-assembled micelle from poly(epsilon-caprolactone)-poly(ethyl glycol)-poly(epsilon-caprolactone) grafted polyethyleneimine (PCEC-g-PEI). The PCEC-g-PEI micelles, formed by self-assembly method, had mean particle size of ca. 82 nm and zeta potential of +22.5 mV at 37 degrees C, and could efficiently transfer pGFP into HEK293 cells in vitro. Meanwhile, as a model hydrophobic chemotherapeutic drug, honokiol was loaded into PCEC-g-PEI micelles by direct dissolution method assisted by ultrasonication. The honokiol loaded cationic PCEC-g-PEI micelles could effectively adsorb DNA onto its surface, while it could release honokiol in an extended period in vitro. This study demonstrated a novel DNA and hydrophobic chemotherapeutic drug co-delivery system.

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 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.

Preparation and characterization of a porous scaffold based on poly(D,L-lactide) and N-hydroxyapatite by phase separation.

In this study, a series of porous scaffolds were prepared from poly(D,L-lactide) (PLA) and nanohydroxyapatite (HA) using the phase separation method. HA/PLA composite membranes and PLA membranes with a microporous structure (pore size around 10-20 µm) were observed by scanning electron microscopy and these micropores were well distributed throughout the PLA membranes. The surface morphology of HA/PLA composite membranes was significantly improved compared to pure PLA membrane. Also, the mechanical property and contact angle of composite membranes were different from that of pure PLA films. The immortalized rat osteoblastic ROS 17/2.8 cell line was used in this research to study the cell adhesion and proliferation behavior, and the results indicated that composite membranes had great cell affinity and good biocompatibility.

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.