Biomedical subjects

Shaobing Zhou

Publications and source records attributed to Shaobing Zhou.

4 recordsLinked to original sources

PubMed2003

Poly-D,L-lactide-co-poly(ethylene glycol) microspheres as potential vaccine delivery systems.

Adjuvants aimed at increasing the immunogenicity of recombinant antigens remain a focus in vaccine development. Worldwide, there is currently considerable care for the development of biodegradable microspheres as controlled release of vaccines, since the major disadvantage of several currently available vaccines is the need for repeated administration. Microspheres prepared from the biodegradable and biocompatible polymers, the polylactide (PLA) or polylactide-co-glycolide (PLGA), have been shown to be effective adjuvants for a number of antigens. This review mainly focuses on polylactide-co-poly(ethylene glycol) (PELA) microspheres adjuvant as vaccine delivery systems by summarizing our and other research groups' investigation on properties of the microspheres formulation encapsulating several kinds of antigens. The results indicate that compared with the commonly used PLA and PLGA, PELA showed several potentials in vaccine delivery systems, which may be due to the block copolymer have its capability to provide a biomaterial having a broad range of amphiphilic structure. PELA microspheres can control the rate of release of entrapped antigens and therefore, offer potential for the development of single-dose vaccines. The PELA microspheres have shown great potential as a next generation adjuvant to replace or complement existing aluminum salts for vaccine potential. The review mainly aims to promote the investigation of PELA microspheres adjuvant for antigens for worldwide researcher.

Animals↗

PubMed2003

Investigation of nanocomposites based on semi-interpenetrating network of [L-poly (epsilon-caprolactone)]/[net-poly (epsilon-caprolactone)] and hydroxyapatite nanocrystals.

In this paper the semi-interpenetrating network (semi-IPN) technique was used for the first time to prepare bone implant composites containing hydroxyapatite (HAP) nanocrystals. The prepared nanocomposites are expected to combine several property advantages including good mechanical strength, modified degradation rate and excellent osteoconductivity. The semi-IPN matrix based on the linear poly (epsilon-caprolactone) (L-PCL) and the network poly (epsilon-caprolactone) (net-PCL) structures are revealed to be phase separation structures. The morphology of net-PCL is featured by intracrosslinked microdomains (1-10 microm) that further interconnect with each other to form the network over the whole sample. The net-PCL component is totally amorphous at room temperature for the nanocomposites containing HAP up to 12.3 wt%. Further, the crystallinity of L-PCL is greatly decreased due to the presence of net-PCL as compared with that for pure L-PCL. The incorporation of L-PCL into the net-PCL network could significantly improve the mechanical properties of pure net-PCL. A great improvement in mechanical properties is observed for the nanocomposites if the HAP content is increased to 15.8 wt%. This transition is in agreement with that the net-PCL component changes from amorphous state to crystalline state at this composition.

Biocompatible Materials↗

PubMed2003

Biodegradable poly(epsilon-caprolactone)-poly(ethylene glycol) block copolymers: characterization and their use as drug carriers for a controlled delivery system.

Poly(epsilon-caprolactone)-poly(ethylene glycol) (PECL) copolymers were synthesized from polyethylene glycol (PEG) and epsilon-caprolactone (epsilon-CL) using stannous octoate as catalyst at 160 degrees C by bulk polymerization. The effect of the molecular weight of PEG and the copolymer ratio on the properties of the copolymers was investigated by (1)H-NMR, IR, DSC and GPC. PCL and PECL microspheres containing human serum albumin were elaborated by solvent extraction method based on the formation of double w/o/w emulsion. Microspheres were characterized in terms of morphology, size, loading efficiency, and the efficiency of microspheres formation. The results show that the microspheres prepared from PECL-10 and PECL-15 copolymers achieved the highest loading efficiency (about 50%) among all copolymers. These results indicate that the properties of copolymers could be tailored by adjusting polymer composition. It is suggested that these matrix polymers may be optimized as carriers in the protein (antigen) delivery system for different purposes.

Calorimetry, Differential Scanning↗

PubMed2002

Study on biodegradable microspheres containing recombinant interferon-alpha-2a.

In this work, a new microsphere delivery system comprising calcium alginate microcores surrounded by a biodegradable poly-DL-lactide-poly(ethylene glycol) (PELA) coat was designed to improve the loading efficiency and stability of peptide drugs. Recombinant interferon (IFN)-alpha-2a, used as a model peptide drug, was efficiently entrapped within the alginate microcores using a high-speed stirrer and then microencapsulated into PELA copolymer using a water-in-oil-in-water solvent extraction method. Microspheres were characterized in terms of morphology, size and distribution, encapsulation efficiency, IFN biological activity retention and in-vitro peptide release. The IFN potency test showed that IFN entrapped in the core-coated microspheres could retain its biological activity during the encapsulation and release procedure. The release profiles were determined by the measurement of peptide presenting in the release medium at various intervals. The IFN potency, calculated by the Wish cells/vesicular stomatitis virus system, was used to determine IFN biological activity. The results showed that the core-coated microspheres could stabilize IFN in the PELA matrix. We compared the new deliverysystem with conventional microsphere delivery systems based on biodegradable poly-DL-lactide and poly-DL-lactide-poly(ethylene glycol). The core-coated microspheres had the highest amount of entrapment, encapsulation efficiency and biological activity retention. The extent of burst release (14%) from the core-coated microspheres in the initial protein release was much lower than the 31% burst release from the conventional microspheres. In conclusion, this work presents a new approach for water-soluble macromolecular drugs delivery (e.g. protein, peptide drugs, vaccines).

Biotechnology↗