A sensitive and real-time assay of trypsin by using molecular imprinting-based capacitive biosensor

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A sensitive and real-time assay of trypsin by using molecular imprinting-based capacitive biosensor

Gizem Ertürk a,b, MartinHedström a,b, BoMattiasson a,b,n
a Department of Biotechnology,Lund University,Lund,Sweden
b CapSenze Biosystems AB,Lund,Sweden

Article history: Received 8 June 2016
Received inrevised form 11 July 2016
Accepted 12 July 2016
Available online 16 July 2016
Keywords: Capacitive biosensor Microcontact imprinting Selectivity Cross-reactivity

Use of a highly sensitive, selective capacitive biosensor is reported for label-free, real-time, easy and rapid detection of trypsin by using the micro contact imprinting method. Real-time trypsin detection was performed with trypsin-imprinted (trypsin-MIP) capacitive electrodes using standard trypsin solutions in the concentration range of 1.0_10_13–1.0_10_7 M with a detection limit of 3.0_10_13 M. Selectivity and cross-reactivity of the system were tested by using competing proteins including chymotrypsin (chy), bovine serum albumin (BSA), lysozyme (lyz) and cytochromec (cytc) in singular and competitive manner and the selectivity of the system was determined with the selectivity coefficients of approximately 705.1,6.5,6.4 and 5.1 for chy, BSA, lyz and cytc, respectively. The trypsin-MIP capacitive electrode was used for 80 assays during 2 months and retained its binding property during all that time with a decrease of approximately 2.3% in the signal amplitude. In the last step, trypsin activity was measured by using Nα-Benzoyl-D, L-arginine 4-nitro anilide hydrochloride (BAPNA) as the substrate with spectro- photometer at 410nm. The trypsin activity was measured as 9mU/mL by spectrophotometer while the amount of captured enzyme calculated from the capacitives ystem was 7.9 mU/mL which shows the correlation between two methods. From the comparison it is obvious that the new method is an attractive alternative for assaying trypsin and the developed capacitive system might be used successfully to monitor label-free, real-time enzymatic.