Gold Nanoparticle-Based Biosensing Techniques

Gold nanoparticles (AuNPs) have emerged as versatile platforms for biosensing owing to their distinctive optical properties, facile surface functionalisation and biocompatibility. The strong localised surface plasmon resonance of AuNPs produces intense colour changes upon aggregation or refractive index shifts, enabling simple visual or spectrometric readouts. Conjugation of AuNPs with antibodies, aptamers or oligonucleotides allows selective recognition of biomolecular targets from proteins and nucleic acids to small metabolites and environmental toxins. Plasmonic techniques, such as colourimetric assays and surface-enhanced Raman scattering, offer rapid, label-free detection, while electrochemical and luminescence-based strategies expand sensitivity in complex samples. Recent advances have focused on amplification strategies, including switchable linkers and self-assembled targets, as well as integration with microfluidics, smartphone-based imaging and point-of-care devices. Applications span from viral RNA detection to cancer biomarker quantification and heavy-metal monitoring, reflecting the global significance of rapid, low-cost diagnostics. Ongoing research aims to enhance multiplexing, reduce non-specific aggregation and improve quantitative accuracy, bringing AuNP-based biosensors ever closer to widespread clinical and field deployment.

Research from Nature Portfolio

Recent studies have demonstrated a disulfide-induced self-assembly strategy for label-free colourimetric detection of nucleic acids. Thiol-modified probes hybridise at each end of target DNA or RNA, forming continuous disulfide bonds that generate flexible, sulphur-rich self-assembled products. These assemblies strongly adhere to gold nanoparticle surfaces, preventing salt-induced aggregation and producing a clear visual signal for perfectly matched versus mismatched sequences.

Another foundational development introduced switchable linkers to precisely control the extent of nanoparticle aggregation. In the absence of target, linkers bridge functionalised AuNPs to promote aggregation, while target binding deactivates linker function and disperses particles. By calibrating linker concentration and nanoparticle ratio, this approach achieves ultrahigh sensitivity with visible detection limits in the femtomolar range for proteins and bacterial cells.

Gold Nanoparticle-Based Biosensing Techniques publication trend

The graph below shows the total number of articles in gold nanoparticle-based biosensing techniques across all publications each year (not limited to Nature Index journals).

Technical terms

Localised Surface Plasmon Resonance (LSPR): Collective oscillation of conduction electrons in AuNPs that enhances light absorption and scattering at specific wavelengths.

Colourimetric detection: Visual or spectrophotometric readout based on nanoparticle aggregation-induced colour changes.

Surface-Enhanced Raman Scattering (SERS): Amplification of Raman signals by AuNPs to detect trace analytes with molecular specificity.

Aptamer: Short, single-stranded oligonucleotide that binds a target molecule with high affinity and specificity.

Switchable linkers: Molecular connectors that can toggle between active and inactive states to regulate nanoparticle aggregation in response to target binding.

Disulfide self-assembly: Formation of extended sulphur-rich products via thiol linkages on target nucleic acids, used to modulate AuNP surface interactions.

References

1. Gold Nanoparticle-Based Plasmonic Biosensors. Biosensors (2023).
2. Disulfide-induced self-assembled targets: A novel strategy for the label free colorimetric detection of DNAs/RNAs via unmodified gold nanoparticles. Scientific Reports (2017).
3. Enhancing Nanoparticle-Based Visible Detection by Controlling the Extent of Aggregation. Scientific Reports (2012).
4. Gold Nanoparticles Based Optical Biosensors for Cancer Biomarker Proteins: A Review of the Current Practices. Frontiers in Bioengineering and Biotechnology (2022).
5. Molecular detection using aptamer-modified gold nanoparticles with an immobilized DNA brush for the prevention of non-specific aggregation. RSC Advances (2021).