Biomedical subjects

Shaobing Zhou

Publications and source records attributed to Shaobing Zhou.

11 recordsLinked to original sources

PubMed2007

Synthesis and characterization of biocompatible Fe3O4 nanoparticles.

In this study, magnetite (Fe3O4) nanoparticles with a size range of 8-20 nm were prepared by the modified controlled chemical coprecipitation method from the solution of ferrous/ferric mixed salt-solution in alkaline medium. In the process, two kinds of surfactant (sodium oleate and polyethylene glycol) were studied; then, sodium oleate was chosen as the apt surfactant to attain ultrafine, nearly spherical and well-dispersed (water-base) Fe3O4 nanoparticles, which had well magnetic properties. The size and size distribution of nanoparticles were determined by particle size analyzer. And the magnetite nanoparticles was characterized by X-ray powder diffraction (XRD) analysis, transmission electron microscopy (TEM), electron diffraction (ED) photography, Fourier transform infrared spectrometer (FT-IR), and vibrating-sample magnetometer (VSM). Also the effect of many parameters on the Fe3O4 nanoparticles was studied, such as reaction temperature, pH of the solution, stirring rate and concentration of sodium oleate. And the 5-dimethylthiazol-2-yl-2,5- diphenyltetrazolium bromide (MTT) assay was performed to evaluate the biocompatibility of magnetite nanoparticles. The results showed that the Fe3O4 nanoparticles coated by sodium oleate had a better biocompatibility, better magnetic properties, easier washing, lower cost, and better dispersion than the magnetite nanoparticles coated by PEG.

3T3 Cells↗

PubMed2006

Shape memory properties of poly(D,L-lactide)/hydroxyapatite composites.

Poly(D,L-lactide) (PDLLA) and Hydroxyapatite (HA) are compounded, which possess biodegradation, biocompatibility and shape memory properties. In the paper, we prepared serial imposing shape memory composites with different shapes, composite ratios and sample thicknesses. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were carried out to examine surface morphology, glass transition temperature (Tg), dynamic mechanical properties, and shape memory effect of PDLLA/HA composites, respectively. Moreover, some interesting shape memory behaviors were investigated. The results show that the better disperse morphology of HA grains using the experiment methods, and PDLLA/HA composites at a definite range of compound ratio have much better shape memory effect than pure PDLLA polymer. It indicates that HA particles can improve shape memory effect and PDLLA/HA composites are potential for biomedical applications.

Biocompatible Materials↗

PubMed2006

Investigation of drug release and matrix degradation of electrospun poly(DL-lactide) fibers with paracetanol inoculation.

This study was aimed at assessing the potential use of electrospun fibers as drug delivery vehicles with focus on the different diameters and drug contents to control drug release and polymer fiber degradation. A drug-loaded solvent-casting polymer film was made with an average thickness of 100 microm for comparative purposes. DSC analysis indicated that electrospun fibers had a lower T(g) but higher transition enthalpy than solvent-casting polymer film due to the inner stress and high degree of alignment and orientation of polymer chains caused by the electrospinning process. Inoculation of paracetanol led to a further slight decrease in the T(g) and transition enthalpy. An in vitro drug release study showed that a pronounced burst release or steady release phase was initially observed followed by a plateau or gradual release during the rest time. Fibers with a larger diameter exhibited a longer period of nearly zero order release, and higher drug encapsulation led to a more significant burst release after incubation. In vitro degradation showed that the smaller diameter and higher drug entrapment led to more significant changes of morphologies. The electrospun fiber mat showed almost no molecular weight reduction, but mass loss was observed for fibers with small and medium size, which was characterized with surface erosion and inconsistent with the ordinarily polymer degrading form. Further wetting behavior analysis showed that the high water repellent property of electrospun fibers led to much slower water penetration into the fiber mat, which may contribute to the degradation profiles of surface erosion. The specific degradation profile and adjustable drug release behaviors by variation of fiber characteristics made the electrospun nonwoven mat a potential drug delivery system rather than polymer films and particles.

Absorbable Implants↗

PubMed2006

[Investigation of biodegradable materials as polymeric gene carriers].

This is a study on the biodegradable polymers as gene controlled-released coatings for gene transfer. The PELA (poly (Dl-lactic acid)-co-poly (ethylene glycol), and PLGAE (poly (lactic acid)-co-poly (ethylene glycol)-co-poly (glycolic acid) random copolymer) were synthesized and prepared as the coatings of plasmid pCH110 in the transfection. All kinds of factors affecting the loading efficiency, cytotoxicity, transfection efficiency and the course of the degradation and release in vitro were discussed. The average diameters of microspheres of PELA and PLGAE were 1-3 microm and 0.72 microm respectively. The loading efficiency levels of them were 62% and 70% respectively. The transfection efficiency levels of two kinds of pCH110 delivery system for COS-1 cells were higher and two of them had few cytotoxicity. After transfection, the X-gal assay was performed and reported positive for 96 h. The biodegradable polymeric materials as gene carriers possess their potential superiority.

Biocompatible Materials↗

PubMed2004

Novel biodegradable polymers as gene carriers.

This study investigated two new biodegradable polymers as gene controlled-released coatings for gene transfer. Poly(ethylene glycol)-co-poly(D,L-lactic acid) (PELA) and poly(ethylene glycol)-co-poly(lactic acid)-co-poly(glycolic acid) random copolymer (PELGA) were synthesized and used as microspheres matrices with encapsulated plasmid pCH110. The plasmid loading efficiency, cytotoxicity, transfection efficiency and in vitro degradation and release profiles of microsphere complexes were evaluated in details. The biodegradable polymers showed high DNA loading efficiency and low cytotoxicity as gene controlled-released coatings, and the poly(ethylene glycol) (PEG) contents of polymer matrices influenced the diameter, loading efficiency and transfection efficiency of plasmid DNA within the microspheres. The average diameters of PELA and PELGA microspheres were between 0.5 and 1.5 microm, and the plasmid loading efficiency was 62 and 73% for PELA and PELGA microspheres with 10% PEG content, respectively. In vitro testing showed a gradual release profile of DNA from polymeric matrices. The polymers/DNA microspheres had high transfection efficiency and early gene expression and maintenance of gene expression level for up to 96 h, although transfection efficiency were slightly lower than that of liposome in the initial 24 h. The biodegradable polymeric materials possess potential superiority as gene carriers.

Animals↗

PubMed2004

Preparation and characterization of biodegradable microspheres containing hepatitis B surface antigen.

Poly-DL-lactide-poly(ethylene glycol) (PELA) microspheres containing Hepatitis B surface antigen (HBsAg) were elaborated by a solvent extraction method based on the formation of a double water/oil/water (w/o/w) emulsion. Microspheres were characterized in terms of morphology, size and size distribution, encapsulation efficiency, and the efficiency of microsphere formation (EMF). Transmission electron microscopy (TEM) and polyacrylamide gel electrophoresis (PAGE) were used to investigate the structural integrality of HBsAg encapsulated in PELA microspheres. The release profile was investigated by the measurement of antigen present in the release medium at various intervals. The PELA-10 microspheres displayed the highest antigen encapsulation efficiency (about 80%), and antigen molecules could be stabilized in the PELA-10 microspheres during the preparation process. It suggested that the PELA microspheres had a great potential as a new polymer adjuvant for HBsAg. The release of Hepatitis B surface antigen from poly-DL-lactide-poly(ethylene glycol) microspheres.

Adjuvants, Immunologic↗

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↗

PubMed2003

[Experimental study of controlled release microencapsulated Salmonella typhi capsular polysaccharide vaccines immunized mice].

Salmonella Typhi capsular polysaccharide vaccines were encapsulated in the Micro-particles made from polyethylene glycol-poly-DL-lactide (PELA). BALB/c mouse were divided into three groups with 20 mice in each. Mouse were immunized respectively with controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines and Salmonella Typhi capsular polysaccharide vaccines by oral and subcutaneous administration. The mice blood and salvia were collected at the 2nd, 4th and 8th weeks respectively for the titrating of IgG and sIgA antibodies by RIA. At the 8th week, live typhoid bacteria were injected into the immunized mice for the calculation of the rate of immunization protection. The IgG titers of the controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines group were higher than those of the other groups(P < 0.05). The IgA titers of the low groups of controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines (oral and subcutaneous) were higher than those of the group of Salmonella Typhi capsular polysaccharide vaccines (P < 0.05). The immunization protection rates of the three groups were 40%, 100% and 60% respectively. The controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines possess the advantages of releasing slowly in vivo and persisting long time immunogenicity.

Administration, Oral↗

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↗