Vascularization Approaches in Tissue Engineering: Recent Developments on Evaluation Tests and Modulation.

This review focuses on vascularization and strategies involved in its evaluation and modulation. Clinical issues associated with engineered tissues of an atomically relevant size that require a vascular network to supply their cells with nutrients and oxygen are analyzed in terms of vascular network formation within scaffolds, which can be produced from varying biomaterials, with the capability of connecting to the vasculature of the patient. Developing angiogenesis techniques and monitoring of angiogenesis development as well as how these methods can be further utilized to tailor vascularization within large tissue engineered constructs are also discussed.

Plasmids for Independently Tunable, Low-Noise Expression of Two Genes.

Some microbiology experiments and biotechnology applications can be improved if it is possible to tune the expression of two different genes at the same time with cell-to-cell variation at or below the level of genes constitutively expressed from the chromosome (the "extrinsic noise limit"). This was recently achieved for a single gene by exploiting negative autoregulation by the tetracycline repressor (TetR) and bicistronic gene expression to reduce gene expression noise. We report new plasmids that use the same principles to achieve simultaneous, low-noise expression for two genes in The TetR system was moved to a compatible plasmid backbone, and a system based on the repressor (LacI) was found to also exhibit gene expression noise below the extrinsic noise limit.