Research Progress on Nanomaterials in SPR Sensors.

While surface plasmon resonance (SPR) sensors serve as vital tools for biomolecular detection; conventional versions suffer from inherent limitations, including confined localized electromagnetic fields and inadequate sensitivity for detecting low-abundance analytes. Consequently, this paper reviews the progress of research in nanomaterial-enhanced SPR sensors to address these challenges. Initially, the review elaborates on the sensing principles and signal modulation strategies of SPR sensors. It systematically analyzes the enhancement mechanisms of noble metal nanoparticles (ranging from spherical 0D to advanced anisotropic 1D/2D nanostructures), magnetic nanoparticles (MNPs), and two-dimensional (2D) nanomaterials, alongside their applications in the detection of small molecules, nucleic acids, and biomacromolecules. Crucially, this review provides a comparative benchmarking of these materials, evaluating their trade-offs between sensitivity enhancement and practical stability. Furthermore, it identifies critical bottlenecks in industrialization, specifically addressing environmental challenges such as thermal cross-sensitivity and oxidative degradation, alongside issues of reproducibility and standardization. Finally, future research directions are proposed, including developing novel nanomaterials, exploring low-cost alternatives, and constructing flexible wearable sensing systems.