Recent advances in nanomaterial-based optical biosensors and their biomedical and biopharmaceutical applications

Optical biosensors are gaining popularity owing to their portability, miniaturization, no requirement for additional attachments, and rapid responsiveness. These features render them suitable for various applications including at-home diagnostics, pharmacology, and continuous molecular monitoring. The integration of functionalized low-dimensional nanomaterials (zero-dimensional (0D), 1D, 2D, and 3D) has redirected focus towards the design, fabrication, and optimization of optical biosensors. This review summarizes the fundamental mechanisms underlying optical biosensing. The key mechanisms include localized surface plasmon resonance (LSPR), photoluminescence (PL), surface enhancement Raman scattering (SERS), nanozyme-based colorimetric strategies, chemiluminescence, bioluminescence, and electrochemiluminescence. The advantages of various low-dimensional nanomaterials for different types of optical biosensors are presented. This comparison emphasizes their potential superiority in targeted biosensing applications. Therefore, promoting optical biosensing techniques and recent developments in advanced biosensing strategies for biomedical research and biopharmaceutical applications are necessary to establish their future directions.