Diffusion of interleukin-2 from cells overlaid with cytocompatible enzyme-crosslinked gelatin hydrogels.

In designing an implantable cell encapsulation construct to continuously deliver therapeutic proteins to a patient, it is critical that the biomaterial be compatible with the encapsulated cells, as well as conducive to the diffusion of desired molecules. As a continuation of our previous work, which demonstrated the cytocompatibility of gelatin hydrogels enzymatically crosslinked by microbial transglutaminase (mTG-gels), this work seeks to elucidate the diffusion properties that are needed for sustained release of therapeutic proteins produced by the engineered cells. HEK293 cells genetically engineered to secrete an anticancer drug, interleukin-2 (hIL2), through 4% mTG-gels used as a 1D diffusion model.

Transglutaminase crosslinked gelatin as a tissue engineering scaffold.

Gelatin is one of the most commonly used biomaterials for creating cellular scaffolds due to its innocuous nature. In order to create stable gelatin hydrogels at physiological temperatures (37 degrees C), chemical crosslinking agents such as glutaraldehyde are typically used. To circumvent potential problems with residual amounts of these crosslinkers in vivo and create scaffolds that are both physiologically robust and biocompatible, a microbial transglutaminase (mTG) was used in this study to enzymatically crosslink gelatin solutions.

Integrated non-invasive system for quantifying secreted human therapeutic hIL2.

Cell encapsulation has been used to treat diabetes, amyotrophic lateral sclerosis, and other chronic ailments by the secretion of therapeutic proteins in vivo. Detection of these proteins typically requires invasive procedures such as blood sampling or device extraction, however. In this article, a non-invasive means of measuring secreted protein concentration using a co-expressed red fluorescent protein marker is developed.

Counteracting apoptosis and necrosis with hypoxia responsive expression of Bcl-2Delta.

In the encapsulated environment of biohybrid artificial organs, cells often encounter a deficiency in oxygen, which lead to apoptosis, necrosis, and lost of productivity. Two vectors with constitutive CMV promoters were constructed to examine the ability of Bcl-2Delta to help C2C12 mouse myoblasts maintain exogenous protein production under hypoxia. Two additional vectors with hypoxia-inducible promoters (5HRE) that switched on Bcl-2Delta expression based on low oxygen levels (0.

Poly(vinyl alcohol) : a potential matrix for glucose oxidase immobilization?

Considerable effort has been focused on the method of immobilizing glucose oxidase (GOD) for amperometric glucose biosensors since the technique employed may influence the available activity of the enzyme and thus affect the performance of the sensor. Narrow measuring range and low current response are still considered problems in this area. In this work, poly(vinyl alcohol)(PVA) was investigated as a potential matrix for GOD immobilization.