Quantitative Enzyme Detection in Reporter Hydrogel-Coated Paper Using a Smartphone Camera.

There is a growing demand for rapid and sensitive detection approaches for pathogenic bacteria that can be applied by non-specialists in non-laboratory field settings. Here, the detection of the typical enzyme β-glucuronidase using a chitosan-based sensing hydrogel-coated paper sensor and the detailed analysis of the reaction kinetics, as detected by a smartphone camera, is reported. The chromogenic reporter unit affords an intense blue color in a two-step reaction, which was analyzed using a modified Michaelis-Menten approach.

Proteolytically stabilizing fibronectin without compromising cell and gelatin binding activity.

Excessive proteolytic degradation of fibronectin (FN) has been implicated in impaired tissue repair in chronic wounds. We previously reported two strategies for stabilizing FN against proteolytic degradation; the first conjugated polyethylene glycol (PEG) through cysteine residues and the second conjugated PEG chains of varying molecular weight on lysine residues. PEGylation of FN via lysine residues resulted in increased resistance to proteolysis with increasing PEG size, but an overall decrease in biological activity, as characterized by cell and gelatin binding.