Ultrasensitive caspase-3 activity detection using an electrochemical biosensor engineered by gold nanoparticle functionalized MCM-41: Its application during stem cell differentiation

Abstract

Caspase-3 has a critical role in the apoptotic process and hematopoietic stem cell differentiation and its detection has been a major focus of research interest and attention. In this study, an ultrasensitive novel electrochemical biosensor for convenient, sensitive and selective detection of caspase-3 activity was developed. Gold nanoparticles functionalized silica-based mesoporous material (MCM-41) modified glassy carbon electrode was designed and fabricated for measurement of caspase-3 activity, more importantly, in its active form. Thiolated MCM-41 was decorated by gold nanoparticle using post modification method and characterized by different analytical methods such as atomic force microscopy, FTIR spectroscopy, scanning electron microscopy and X-ray diffraction. Hydroquinone was used as electroactive mediator. The biotinylated peptide was self-assembled on gold nanoparticles-MCM-41. The electrochemical behavior of the prepared biosensor was investigated by electrochemical techniques. The use of gold nanoparticles resulted in a significant improvement in the radial mass transfer flux at the electrode surface and enhancement in the electrochemical signal. Under the optimized conditions, the assay's lower limit of quantification (LLOQ) was obtained as 5 femtomolar (fM) with a relative standard deviation of 0.67%. Finally, the proposed biosensor was successfully applied for detection of caspase-3 activity during hematopoietic stem cell differentiation steps as a real sample. (C) 2016 Elsevier B.V. All rights reserved.