Sers-sensing hydrogels for in situ detection of genetically modified organisms

Overview

This technology adapts SERS-sensing hydrogels—originally developed for in situ detection of plant viral infections—to the direct detection of genetically modified organisms (GMOs) in the field. The platform addresses the need for rapid, on-site genetic testing without the laboratory infrastructure required by PCR-based methods. By modifying the post-contact processing of the hydrogel, the team aims to free genomic DNA from plant tissue and detect GMO-specific sequences directly on the leaf surface.

The approach offers a practical solution for agricultural stakeholders, regulatory bodies, and seed producers who need fast, portable confirmation of GMO status. Its field-ready design, multiplexed readout, and minimal sample preparation make it well suited for deployment in greenhouses, field testing stations, and supply chain verification.

Technical specifications

Core technology components:

• Hydrogel matrix that simultaneously extracts genetic material from abraded leaf surfaces and serves as the substrate for embedded sensors
• Metallic nanostars coated with functional nucleic acids, engineered for high-sensitivity SERS detection and demonstrated specificity down to single-nucleotide differences
• Reagentless sensing mechanism based on surface-enhanced Raman scattering, eliminating the need for labeled reagents or amplification steps
• Handheld Raman reader compatibility for portable, on-site interrogation
• Multiplexed optical readout enabled by narrow SERS spectral peaks, allowing simultaneous detection of multiple target sequences in a single assay

Detection workflow:

• Light abrasion of the leaf surface to expose interstitial fluid
• Hydrogel contact for analyte uptake (approximately 30 minutes)
• Post-contact treatment to release genomic DNA, with planned optimization of temperature ramping and buffer ionic strength
• SERS interrogation using a 785-nm laser to identify and quantify target genetic sequences

Validation status to date:

• Tested on tobacco plants inoculated with tobacco mosaic virus across resistant and susceptible varieties
• SERS signal trends correlated with western blot quantification of viral load
• Detection achieved as early as two days post-inoculation in both plant types

Technology readiness level

The SERS-sensing hydrogel platform has been validated for viral detection in plants through controlled greenhouse experiments. The current TRL reflects demonstrated proof-of-concept for the core sensing mechanism and hydrogel-based extraction, with viral load quantification confirmed by orthogonal methods.

The proposed work focuses on extending the platform to GMO detection, which requires optimizing post-contact processing to free genomic DNA and validating sensor compatibility with plant genetic material. Planned activities include evaluating temperature and buffer conditions for DNA release, testing multiplexing with multiple GMO-specific sensors, and introducing remedial strategies if sensor incompatibility arises. The technology is positioned at an early-to-mid stage of development for GMO applications, with a clear pathway toward field validation and multiplexed assay deployment.