Nanoparticle-Based Multimodal Sensors for Diagnostics and Environmental Monitoring

Engineered nanomaterials with precisely controlled size, morphology, and surface functionality are redefining the performance limits of analytical sensing platforms. Their tunable plasmonic, catalytic, and electronic properties enable the construction of multimodal nanosensors capable of delivering high sensitivity, selectivity, and stability across diagnostic and environmental applications. This presentation focuses on the design and synthesis of responsive nanostructured materials and the development of signal-detection platforms based on material properties such as colorimetric, fluorescent, electrochemical, and surface-enhanced Raman scattering (SERS) sensing.

In this work, gold-based nanostructures—ranging from gold nanoclusters and spherical gold nanoparticles to anisotropic gold nanostars—are highlighted for their strong localized surface plasmon resonance (LSPR), enhanced electromagnetic fields, and quantum-size-dependent redox behavior. These properties are exploited to amplify optical contrast in lateral flow assays (LFA and LFA-SERS) for biological detection through plasmonic coupling and scattering intensification and to improve electrochemical detection (EChem) via accelerated heterogeneous electron-transfer kinetics and catalytic enhancement at the electrode–nanoparticle interface. For example, these mechanisms significantly lower the detection limits for electrochemical sensing of toxic heavy metals (Pb²⁺, Hg²⁺, Cd²⁺, As³⁺) in complex matrices. Beyond gold nanostructures, complementary sensing modalities are also achieved using magneto-fluorescent hybrid nanomaterials—silica-coated carbon dot–ferrite nanocomposites—which enable magnetic preconcentration, reduced matrix interference, and fluorescent sensor readout. These multifunctional platforms support not only fluorescent sensing but also magnetic hyperthermia applications.

The integration of these nanomaterials into devices such as paper-based platforms, microelectrodes, and miniaturized analytical modules is a crucial step that will enable the next generation of nanoparticle-enabled multimodal sensors for diagnostics and environmental monitoring to achieve real-world implementation.