2024 AIChE Annual Meeting

SH3 Binding Titrations with Scp(12)-Modified Gold Surface

Biosensors are defined as having a biorecognition element, which serves to target a specific analyte of interest, and a transduction element, which converts the surface binding response into a readable signal.1 Progress has been made in the development of an SH3 electrochemical biosensor, which will function as a model system for other future analyte targets. Two modification procedures were pursued to investigate the recognition element Scp(12). The first sensor was initially modified with 10 mM 3-Mercaptopropionic Acid (3-MPA) in solvent anhydrous MeOH. The second sensor was initially modified with a 1:1000 of 12-Malondialdehyde (12-MDA) and 1-Dodecanethiol (1-DT) in solvent anhydrous MeOH. Both sensors were subsequently modified with polyhistidine- tagged Scp(12), following several identical modification steps: (1) NHS and EDC; (2) ANTA; (3) NiSO4; (4) polyhistidine-tagged Scp(12). Both modifications were evaluated using Electrochemical Impedance Spectroscopy (EIS) and were confirmed successful.

The interaction between surface-modified recognition element, Scp(12), and target analyte, SH3, were studied using EIS. EIS settings were set to have an initial frequency of 100000 Hz, a final frequency of 0.2 Hz, 10 points/decade, an AC Voltage of 10 mV rms, and a DC Voltage of 0.160 V vs Ag/AgCl. All EIS data was collected in a 10 mM FFCN in PBS solution. Using a small volume cell setup that initially held 210 µL of the FFCN solution, concentrations of SH3 ranging from 0.190 µM to 190 µM were titrated into the base solution via seven concentration additions. Initial findings suggest a response from the scp(12)/SH3 or recognition element/analyte interaction as there is a substantial difference between SH3 data and the buffer data.

Acknowledgements: Support was provided by BIO-SENS, National Science Foundation EPSCoR award (#2119237).

References:

  1. Ren, T.; Bramlitt, S. E.; Joelle M.J. LaFreniere; Seitz, W. Rudolph.; Jeffrey Mark Halpern. Conformation-Based Stimuli-Response Sensors: Strategies for Optimizing Electrochemical and FRET Transduction. Sensors and Actuators Reports 2021, 3, 100066–100066. https://doi.org/10.1016/j.snr.2021.100066.