Bioelectronic modulation of single-wavelength localized surface plasmon resonance (LSPR) for the detection of electroactive biomolecules

The simplification of localized surface plasmon resonance (LSPR) detection can further promote the development of optical biosensing application in point-of-care testing. In this study, we proposed a simple light emitting diode (LED) based single-wavelength LSPR sensor modulated with bio-electron transfers for the detection of electroactive biomolecules. Indium tin oxide electrode loaded with nanocomposites of polyaniline coated gold nanorod was used as LSPR chip, and the applied electric potential was scanned at the LSPR chip for single-wavelength LSPR biosensing. Under the scanning of applied potentials, biological electron transfer of redox reaction was employed to demonstrate the bioelectronic modulation of single-wavelength LSPR for selective electroactive biomolecule detection. Without any additional recognition material, electroactive biomolecules uric acid and dopamine were detected directly with a sensitivity of 5.05 μmol/L and 7.11 μmol/L at their specific oxidation potentials, respectively. With the simplified optical configuration and selective bioelectronic modulation, the single-wavelength LSPR sensor is promising for the development of simple, low-cost, and high specificity optical biosensor for point-of-care testing of electroactive biomolecules.