Nanobioengineered platforms for photoelectrochemical detection of C-reactive protein

Abstract

ABSTRACT : Photoelectrochemical (PEC) biosensors are an emerging field of analytical devices designed to detect and quantify (bio)analytes in clinical samples. These biosensors utilize light and photoactive nanomaterials to generate charge carriers and promote redox reactions on the electrode surface, with changes in electric current or potential correlated with the concentration of the (bio)analyte. However, challenges in advancing PEC biosensors are the instability of biomolecules caused by exposure to high-energy ultraviolet radiation and high-background noise. These drawbacks have been addressed by integrating red-light-activated plasmonic photoactive nanomaterials, which minimize photodamage to biomolecules while reducing background noise in (bio)detection processes. Likewise, energy conversion and charge transfer in PEC detection methods have accelerated with photoactive materials' efficient heterojunction. Additionally, incorporating miniaturized electrodes into PEC systems leads to portable and compact devices, making them ideal for point-of-care and on-site diagnostics. Thus, this work is a red-light PEC platform based on disposable electrodes decorated with plasmonic graphene and gold nanostars (AuNSs) to amplify photocurrent signals in the immunosensing of C-reactive protein (CRP), a crucial biomarker for monitoring inflammation. Anti-CRP antibodies as molecular recognition elements were immobilized by soft bioconjugation strategies on the nanostructured interface. CRP was selectively detected using chronoamperometry under irradiation with a 765 nm wavelength source. The physicochemical, PEC, and morphological properties of the (bio)interface were characterized by PEC, spectroscopic, and microscopic analyses. The analytical and clinical applicability of the PEC nanobiosensor was demonstrated by detecting CRP in serum samples with different levels of inflammatory response. Overall, incorporating plasmonic nanomaterials into miniaturized devices demonstrated the robustness of the red-light PEC system for the sensitive and specific detection of (bio)analytes of biomedical interest, such as CRP. The PEC nanobiosensors are versatile tools for detecting a wide range of biomolecules and offer new low-cost and fast-readout analytical solutions in clinical diagnostics.