Mesenchymal stem cells (MSCs) are partially defined by their ability to differentiate into tissues including bone, cartilage and adipose in vitro, but it is their trophic, paracrine and immunomodulatory functions that may have the greatest therapeutic impact in vivo. Unlike pharmaceutical treatments that deliver a single agent at a specific dose, MSCs are site regulated and secrete bioactive factors and signals at variable concentrations in response to local microenvironmental cues. Significant progress has been made in understanding the biochemical and metabolic mechanisms and feedback associated with MSC response. The anti-inflammatory and immunomodulatory capacity of MSC may be paramount in the restoration of localized or systemic conditions for normal healing and tissue regeneration. Allogeneic MSC treatments, categorized as a drug by regulatory agencies, have been widely pursued, but new studies demonstrate the efficacy of autologous MSC therapies, even for individuals affected by a disease state. Safety and regulatory concerns surrounding allogeneic cell preparations make autologous and minimally manipulated cell therapies an attractive option for many regenerative, anti-inflammatory and autoimmune applications.

A previously engineered Methanocaldococcus jannaschii –tyrosyl-tRNA synthetase pair orthogonal to Escherichia coli was modified to become orthogonal in mammalian cells. The resulting -tyrosyl-tRNA synthetase pair was able to suppress an amber codon in the green fluorescent protein, GFP, and in a foldon protein in mammalian cells. The methodology reported here will allow rapid transformation of the much larger collection of existing tyrosyl-tRNA synthetases that were already evolved for the incorporation of an array of over 50 unnatural amino acids into proteins in Escherichia coli into proteins in mammalian cells. Thus we will be able to introduce a large array of possibilities for protein modifications in mammalian cells.

The potential usefulness of artificially selected peptides as probes to detect specific proteins has been proposed because of the ease and low cost of syntheses, manipulation and genetic expression. However, the affinities of these peptides to their target proteins are generally too low to be practical as diagnostic or bio-analytical reagents. One approach to this problem is to incorporate a redox-active amino acid 3,4-dihydroxy-L-phenylalanine (L-DOPA) which selectively forms a covalent linkage to the target protein. Such peptide-based probes can also be fused to tailored reporter proteins and easily expressed in bacterial cultures. As a demonstration, a candidate peptide TOP1 that weakly binds to the target protein, the SH3 domain of human Abl kinase, was fused to green fluorescent protein (GFP) and L-DOPA was site-specifically incorporated into the peptide region (TOP1-DOPA-GFP). TOP1-DOPA-GFP produced from E. coli was used in a Western blot-type experiment to show that the Abl SH3 domain can be detected in one step by observing the fluorescence. The molecular design presented in this work is significant in that the same approach could be used to transform many other protein-binding peptides with insufficient affinities into protein detection probes with a variety of fused reporter or therapeutic proteins.

High density inkjet printing of protein solutions was investigated for photonic crystal based microarray applications. Spacing of 60um has been demonstrated between unique inkjetprinted spots on a silicon substrate.

The study of protein-protein interactions is critical for the understanding and regulation of biological systems. To that end, yeast two-hybrid systems have been used to study protein-protein interactions in vivo, but they frequently suffer from a high incidence of false positives when applied to mammalian systems. A novel mammalian two-hybrid system has recently been developed which exhibits lower background and higher sensitivity than earlier mammalian two-hybrid systems. It has successfully detected interactions with dissociation constants ranging from 0.99 nM to 55 μM. The system was built upon the tetracycline repressor-tetracycline operator interaction and is suitable for use in the study of most, if not all, mammalian protein-protein interactions.