Poly lactic acid based scaffolds for vascular tissue engineering

Abstract

A critical obstacle encountered by tissue engineering is the inability to maintain large masses of living cells upon transfer from the in vitro culture conditions to host in vivo. Capillaries, and the vascular system, are required to supply essential nutrients, including oxygen, remove waste products and provide a biochemical communication "highway". The successful use of tissue-engineered constructs is currently limited to thin or avascular tissues, such as skin or cartilage, for which post-implantation neovascularisation from the host is sufficient to meet the demand for oxygen and nutrients. To succeed in the application of tissue engineering for bigger tissues, such as bone or muscle, the problem of vascularisation has to be solved. Another task in this research field is the possibility to tune the biodegradability of the scaffold. After implantation, the scaffold must be gradually populated by cells and replaced by extra cellular matrix; with this respect, it is crucial that this replacement takes place with appropriate dynamics and a well-defined timescale. A premature degradation, in fact, could lead to a collapse of the structure as the newly generated tissue could not have reached yet the suitable mechanical properties. Conversely, a long degradation time could delay or completely interrupt the development of the new tissue. In this work scaffolds for vascular tissue engineering (VTE) were produced and characterized, utilizing several PLLA/PLA blends (100/0, 90/10, 75/25 wt/wt) in order to tune the biodegradability of the scaffolds. Cell culture into the scaffold were carried out and the noncytotoxicity of "scaffolds", adhesion and cell proliferation inside them were evaluated. The results have shown that the scaffold do not induce cell toxicity; cells are able to grow into the tubular shape scaffold covering its internal surface, so they can be considered suitable for the application for the designed aimed. Copyright © 2012, AIDIC Servizi S.r.l.