Rapid Colorimetric Point-of-Care Detection and Imaging of Multiple Biomolecules Using Liquid Crystal Composite on Gold Nanoisland Thin Films as a Label-Free Optical Biosensor

Timely and precise identification of infections is pivotal for effective treatment and curtailing disease transmission. While single biomarkers have historically served diagnostic purposes, their limitations in sensitivity and specificity necessitate a more comprehensive approach. The simultaneous detection of multiple biomolecules holds promise in enhancing accuracy, expediting analysis, and bolstering pathology screening. Thus, the imperative to engineer a noninvasive biosensor capable of concurrently quantifying diverse infection-associated biomarkers, such as albumin proteins and bacterial molecules, is undeniable. In this pursuit, a novel biosensor has been synergistically developed, harnessing a color-indicating optical platform employing gold nanoisland films (AuNIFs) enveloped by cholesteric liquid crystals (CLCs). The integration of CLCs and AuNIFs capitalizes on their sensitive interfacial interactions, underscoring the potential for robust biosensing. Variations in biomolecule concentrations trigger discernible alterations in CLC-AuNIF interface alignment, thus profoundly impacting the hybrid plasmonic-photonic behavior of AuNIFs. The resulting CLCs-AuNIFs biosensor showcases exceptional sensitivity and precision in discerning E.coli concentrations and albumin levels. Notably, the biosensor boasts a label-free limit of detection, achieving an impressive 1 × 106 CFU/ml for E.coli and 10 ng/ml for BSA. This innovative CLCs-AuNIFs biosensor boasts swiftness, visual discernibility, label-free operation, and multi-concentration detection capabilities for both microbial agents and albumin. Perturbations in biomolecule concentrations elicit definable shifts in interface alignment, subsequently modulating the hybrid plasmonic-photonic dynamics of AuNIFs. The spectrum of potential applications for this advancement spans biomedical, microbial, and industrial domains. The unified biosensor can revolutionize infection-related diagnostics and containment measures, ideally situated as a point-of-care solution. This landmark development pioneers the realm of multi-biomarker detection in infection diagnosis, holding profound implications for the trajectory of infection diagnostics and therapeutic interventions.