Biomedical subjects

LinShu Liu

Publications and source records attributed to LinShu Liu.

5 recordsLinked to original sources

PubMed2005

Biodegradable composites from sugar beet pulp and poly(lactic acid).

Sugar beet pulp and poly(lactic acid) (PLA) composites were prepared by compression-heating. The resultant thermoplastics had a lower density, but they had tensile strength similar to that of pure PLA specimens as well as the same geometric properties. Tensile properties depended on the initial water content of sugar beet pulp and the process by which composites were manufactured. In comparison with sugar beet pulp, the composite showed improved water resistance. This can be attributed to the hydrophobic character of PLA and pulp-matrix interactions. The composite thermoplastics showed suitable properties for potential use as lightweight construction materials.

Beta vulgaris↗

PubMed2004

Pectin/poly(lactide-co-glycolide) composite matrices for biomedical applications.

The aim of the research was to develop matrices for the delivery of biologically active substances for tissue regeneration. To this end, a new biodegradable matrix composed of a hydrophobic porous poly(lactide-co-glycolide), p(LGA), network entangled with another network of hydrophilic pectin was fabricated in the presence of calcium chloride. The calcium salts function as both a pore forming reagent and cross-linker for the formation of pectin networks; the method combines creating pores and cross-linking polymers in one step. Microscopic imaging and dynamic mechanical analysis revealed a double-network structure of the composite matrices. The pectin enables the composite to carry signal molecules. This is accomplished by linking signal molecules to pectin by physical adsorption or by chemical reaction. The p(LGA) networks in the composite impart mechanical properties comparable to p(LGA) alone. The mechanical properties of the composite are far superior to matrices containing only pectin. Furthermore, the pectin-containing matrices improved cell adhesion and proliferation when compared to plain p(LGA) matrices, as determined in vitro by osteoblast culture.

Adsorption↗

PubMed2003

Pectin-based systems for colon-specific drug delivery via oral route.

Pectin-derived matrices are now being examined and tested for controlled drug delivery. Pectin is intact in the upper gastrointestinal tract and degraded by colonic microflora. The composition of this microflora remains relatively consistent across a diverse human population. Thus, pectin-derived drug carriers provide promising potential for colon-specific drug delivery. This paper reviews recent developments in pectin-derived formulations. Subjects reviewed include gelation of pectin, calcium cross-linked pectinate, composites of pectin and other polymers, technologies to fabricate pectin into useful drug delivery vehicles, and methods to evaluate release kinetics of incorporated drugs. This article discusses advantages, limitations, and possible future developments in pectin-based formulations with particular emphasis on the field of colon-specific drug delivery.

Administration, Oral↗

PubMedDate not supplied

Pectin/zein beads for potential colon-specific drug delivery: synthesis and in vitro evaluation.

Novel complex hydrogel beads were prepared from two edible polymers: pectin, a carbohydrate from citrus fruits, and zein, a protein from corn. The pectin/zein complex hydrogels did not swell in physiological environments, but hydrolyzed in the presence of pectinases. An in vitro study showed the capacity of the hydrogels to endure protease attack and residence time variation. The physical and biological properties of the new hydrogels were attributed to molecular entanglement of the two polymers. The pectin networks were stabilized by the bound zein molecules. In turn, the pectin networks shielded the bound zein from protease digestion.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMedDate not supplied

Pectin gel vehicles for controlled fragrance delivery.

Using citronellal as a model compound, pectin gels formulations were evaluated for the controlled fragrance release by kinetic and static methods. The pectins with higher degrees of esterification induced a stronger molecular association with the nonpolar fragrance. This resulted in a prolonged duration of fragrance release and the limitation of fragrance adsorption to the receptor skin layers. The increase in pectin concentrations suppressed the fragrance release by a diffusion mechanism. Blocking the carboxyl groups of pectin with calcium ions reduces the hydrophilicity of pectin and provides physical barriers for citronellal diffusion. The pectin/calcium microparticles are promising materials for controlled fragrance release.

Acyclic Monoterpenes↗