R. Zlatev, M. Stoytcheva, G. Montero, B. Valdez
Tuesday 6 August 2013 by Libadmin2013

References: 13th SGEM GeoConference on Nano, Bio And Green – Technologies For A Sustainable Future, www.sgem.org, SGEM2013 Conference Proceedings, ISBN 978-619-7105-06-3 / ISSN 1314-2704, June 16-22, 2013, 197 - 204 pp


The biotechnology, the food industry and the medical diagnostic require rapid, sensitive, and reliable methods for trypsin activity determination. A simple approach, which meets successfully all these requirements, based on Quartz Crystal Microbalance (QCM) was developed, analytically characterized and described in the present work. The new approach takes advantage of nanoparticles loaded gelatin employment as a trypsin substrate, deposited on the QCM crystal. The heavier nanoparticles leaving the substrate layer together with the products of its enzymatic gelatin degradation provokes a greater decrease of the total QCM crystal mass compared with the non charged substrate and as a result, a higher sensor frequency response occurs. A 10th fold improvement of the LOD was achieved for trypsin activity evaluation applying Ag nanoparticles loaded gelatin: 7.5x10-4 U mL-1 vs. 7.5x10-3 U mL-1 obtained by the “classic” QCM method. The approach subject of this work can be applied with any substrate degrading enzyme.

Keywords: Trypsin activity determination, Quartz crystal microbalance (QCM), Gelatin substrate, Ag nanoparticles loaded gelatin