Rapid on-site sensor for Cry gene detection in corn using AiCap sensing technology

Overview

This solution offers a rapid, field-deployable biosensor for detecting Cry genes—such as Cry1Aa—in corn samples. Designed for use outside of laboratory settings, the sensor delivers results in approximately 30–60 seconds from sample collection to analysis, enabling timely decisions in agricultural, regulatory, and supply chain contexts. The technology is built on AC electrokinetic capacitive (AiCap) sensing, a proprietary affinity-based detection platform that combines high sensitivity with simple operation. Each disposable sensor costs less than one dollar in materials, making large-scale or routine screening economically practical.

The core value proposition is the ability to perform GMO gene detection on-site without the need for trained laboratory personnel or complex instrumentation. By simply changing the oligonucleotide probe immobilized on the sensor surface, the platform can be adapted to detect different genetic targets, offering flexibility across multiple crop monitoring and biosecurity applications.

Technical specifications

Core technology:

• AC electrokinetic capacitive (AiCap) sensing, a proprietary platform developed at the University of Tennessee, Knoxville
• Interdigitated electrodes (IDEs) fabricated on low-cost printed circuit board substrates
• Disposable sensor format designed for single-use field testing
• Functionalization with oligonucleotide probes complementary to target gene sequences

Performance characteristics:

• Sample-to-result time of approximately 30–60 seconds
• Sub-picomolar (sub-pM) detection limit demonstrated in preliminary studies
• Logarithmic quantitative response across a broad concentration range (validated previously from 250 to 25,000 copies/µL for mecA gene detection)
• Calculated limit of detection as low as 3.4 attomolar (approximately 3 copies/µL) in standard buffer
• High specificity demonstrated through differential response between target and non-target genomic DNA

Operational features:

• User-friendly interface requiring no specialized training
• Low material cost per sensor (under $1)
• Quantification based on the rate of capacitance change at the electrode surface
• Adaptable to different biomarkers by swapping the probe sequence

Validation status for MRSA detection (preliminary basis):

• Successfully distinguished methicillin-resistant (MRSA) from methicillin-susceptible (MSSA) Staphylococcus aureus genomic DNA
• Cross-validated using femB gene probes common to both strains

Technology readiness level

The AiCap sensing platform has been validated for genomic DNA detection in prior studies involving MRSA and MSSA, demonstrating sensitivity, specificity, and rapid response in complex sample matrices. These proof-of-concept results establish the technical foundation for extending the platform to Cry gene detection in corn.

Future validation efforts are planned in three stages: (1) fabrication of AiCap sensors functionalized with Cry1Aa-specific oligonucleotide probes targeting a sequence within the 3,528-nucleotide Cry1Aa gene; (2) characterization of limit of detection, calibration curves, and selectivity in standard solutions; and (3) optimization of corn sample preparation protocols, including grinding, genomic DNA extraction using commercial kits, and testing with spiked field blanks. Positive control samples will be sourced from the University of Tennessee, while negative controls will be obtained from commercial sources, with qPCR used to confirm DNA quality and Cry1Aa presence. The technology is currently at an early-to-mid stage of development, with demonstrated proof-of-concept in a related application and a defined pathway toward GMO-specific validation and field deployment.