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Abstract
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Caspase-3 has a critical role in the apoptotic process and hematopoietic stem cell differentiation andits detection has been a major focus of research interest and attention. In this study, an ultrasensitivenovel electrochemical biosensor for convenient, sensitive and selective detection of caspase-3 activitywas developed. Gold nanoparticles functionalized silica-based mesoporous material (MCM-41) modifiedglassy carbon electrode was designed and fabricated for measurement of caspase-3 activity, more impor-tantly, in its active form. Thiolated MCM-41 was decorated by gold nanoparticle using post modificationmethod and characterized by different analytical methods such as atomic force microscopy, FTIR spec-troscopy, scanning electron microscopy and X-ray diffraction. Hydroquinone was used as electroactivemediator. The biotinylated peptide was self-assembled on gold nanoparticles-MCM-41. The electrochem-ical behavior of the prepared biosensor was investigated by electrochemical techniques. The use of goldnanoparticles resulted in a significant improvement in the radial mass transfer flux at the electrode sur-face and enhancement in the electrochemical signal. Under the optimized conditions, the assay’s lowerlimit of quantification (LLOQ) was obtained as 5 femtomolar (fM) with a relative standard deviation of0.67%. Finally, the proposed biosensor was successfully applied for detection of caspase-3 activity duringhematopoietic stem cell differentiation steps as a real sample.
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