Single Split Resonance Sensor Device for Detection of Bovine Serum Albumin Using Water Soluble Perylenediimide as Probe

Perylenediimides (PDIs) are organic n-type semiconductor molecules with special photophysical and device properties. These molecules are underutilized in biomedical applications. In this work, a water soluble PDI substituted with ethylenediamine at N-imide position [PDI-quaternary ethylenediamine (EDAQ)] is used as a probe molecule and studied for its interaction with bovine serum albumin (BSA) quantitatively. Single split resonator (SSR) devices are fabricated and studied for interaction in the range of 300 MHz-1 GHz with high accuracy and resolution for quantitative identification of BSA using PDI as the probe. SSR device shows high sensitivity, Q-factor and figure of merit (FoM) with sequential shift in resonance frequency with increasing concentration of BSA. Without PDI, no shift was observed in increasing the amount of BSA. The mechanism of interaction between PDI and BSA is interpreted using absorption, fluorescence, and transient absorption spectroscopy (TAS) studies. Charge-separated species appear at 775 nm (1.6 eV) with a lifetime of 220 fs after a 2.3-ps delay of excitation in TAS spectra due to the formation of donor-acceptor charge-transfer complex between BSA and PDI and response in SSR devices is obtained for this C-T complex. PDI probe-based SSR devices are envisaged as potential electronic diagnosis devices with high sensitivity.