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Surface Functionalization Studies in the Development of Nanohole Plasmonic Sensors
Sezin Sayin1,2, Kristen L Steffens2, Kurt D Benkstein2
1Department of Electrical and Computer Engineering, School of Engineering and Applied Science, The George Washington University, Washington, DC 20052, USA.
Sensors (Basel, Switzerland)
|June 12, 2026
Summary
This study demonstrates functionalized nanohole array sensors using localized surface plasmon resonance (LSPR) for sensitive, label-free biomolecular detection. The technology shows promise for portable point-of-care diagnostics, including viral antigen identification.
Area of Science:
- Nanotechnology
- Biomedical Engineering
- Optical Sensing
Background:
- Localized surface plasmon resonance (LSPR) offers enhanced sensitivity and miniaturization potential for biosensing.
- Nanohole array (NHA) sensors leverage LSPR for detecting interfacial changes.
- Biomedical applications require robust surface functionalization for specific biomolecular detection.
Purpose of the Study:
- To investigate surface functionalization of LSPR-based NHA sensors for biomedical applications.
- To demonstrate the immobilization of specific biomolecules on functionalized NHA surfaces.
- To validate the sensor's capability for label-free detection of biomolecular targets.
Main Methods:
- Gold-coated NHA surfaces were functionalized with polyethylene glycol (PEG) self-assembled monolayers (SAMs).
- Bovine serum albumin (BSA) and SARS-CoV-2 nanobody proteins were immobilized on PEGylated surfaces.
- Surface modification and biomolecular immobilization were validated using LSPR spectral shifts and X-ray photoelectron spectroscopy (XPS).
Main Results:
- Successful immobilization of BSA and SARS-CoV-2 nanobodies on PEGylated NHA sensors was confirmed.
- LSPR spectral shifts and XPS analyses validated each functionalization and immobilization step.
- High reproducibility was observed across multiple sensors and trials.
Conclusions:
- The developed NHA-based plasmonic sensor system enables reliable, sensitive, label-free detection of biomolecular targets in liquid.
- The functionalization strategy using PEG-SAMs is effective for specific biomolecule attachment.
- This technology holds potential for portable point-of-care diagnostics, including viral antigen detection.
