Effect of PLA Knitted Structure on the Mechanical Properties of Composite Vascular Scaffold

A new entire biodegradable scaffold has been developed which does not require precelluiarization before transplantation. This new kind of vascular scaffold prototype made from porous poly- e-caprolactone （PCL） membrane to provide three-dimensional environment for cell growth, and embedded with weft-knitted polylactic acid （PLA） fabric to support mechanics. The aim of this paper is to study the variation tendency of mechanical properties with the fabric spacing changing. The basic geometrical parameters were measured to characterize properties of the samples. The tensile and compressive elastic recovery of the samples were tested by the universal mechanical tester and radial compression apparatus, respectively. Both tensile and compressive properties enhanced when reducing the fabric spacing of the composite vascular scaffold.

Synthesis of poly(ethylene glycol)-SS-poly(ε-caprolactone)-SS-poly(ethylene glycol)triblock copolymers via end-group conjugation and self-assembly for reductively responsive drug delivery

In this study,we describe a simple synthesis route to prepare triblock copolymers with disulfide-linkers,poly(ethylene glycol)-SS-poly(ε-caprolactone)-SS-poly(ethylene glycol)(PEG-SS-PCL-SS-PEG)for application in the reductively responsive release of doxorubicin(DOX).To synthesize PEG-SS-PCL-SS-PEG,two end-groups of PCL-diol were first modified with cystamine to introduce disulfide bonds and subsequently conjugated with PEG-NHS via carbodiimide chemistry.PEG-SS-PCL-SSPEG fabricated into polymeric micelles with stable structure and different nanoscale sizes via adjusting the PCL chain length,showing obvious reductive responsiveness and fast drug release of encapsulated DOX in the presence of glutathione(GSH).Moreover,DOX-loaded PEG-SS-PCL-SS-PEG micelles exhibited higher therapeutic efficacy than reduction-insensitive PEG-b-PCL micelles in vitro.Thus,end-groups conjugation is a simple and straightforward strategy to introduce intelligent responsiveness in biocompatible block copolymers and improve their therapeutic efficacy.

Preparation of Composite Particles Made of Biodegradable Polymer and a Few Additives with Phase Separation Followed by Drying-in-Liquid

It was tried to prepare the biodegradable composite particles by the phase separation method followed by the drying-in-liquid method. The composite particles were made of poly-ε-caprolac-tone, quaternary ammonium, carbon black and wax. In the experiment, acetone and water were selected as a good solvent and a poor solvent for poly-ε-caprolactone, quaternary ammonium and wax, respectively. The composite particles were prepared by changing the surfactant species and their concentration, the feeding velocity of water and the weight ratio of poly-ε-caprolactone with larger molecular weight to one with smaller molecular weight. The composite particles with the inner structure in which carbon black, quaternary ammonium and wax were coated well with poly-ε-caprolactone could be prepared by the preparation method presented in this study. The structure and the mean diameter of composite particles were strongly affected by the feeding velocity of water. The higher the feeding velocity of water, the larger the mean diameter of composite particles. The mean diameter was drastically decreased with the surfactant concentration and increased with the added amount of poly-ε-caprolactant with larger molecular weight.