Aerosol Jet Printing-Enabled Dual-Function Electrochemical and Colorimetric Biosensor for SARS-CoV-2 Detection

Current diagnostic methods for viral pathogens often rely on complex laboratory workflows that limit accessibility in remote areas. No prior work had resolved the need for simple, rapid, and integrated testing platforms. Existing techniques frequently require extensive sample preparation or expensive equipment for nucleic acid amplification. That uncertainty drove the development of alternative sensing strategies. Prior research has shown that CRISPR-based systems offer high specificity for genetic targets. However, integrating these molecular tools into portable devices remains a significant challenge. This gap motivated the creation of a platform that combines electrochemical and optical detection. The current study addresses these limitations by utilizing advanced printing techniques for sensor fabrication.

The aim of this research is to develop a dual-function biosensor for the sensitive detection of pathogens using SARS-CoV-2 RNA. The investigators sought to overcome the limitations of current diagnostic methods that require complex laboratory infrastructure. They intended to create a platform that integrates both colorimetric and electrochemical sensing capabilities. The motivation for this work stems from the need for rapid and accurate point-of-care diagnostics. The team focused on eliminating the requirement for complicated target amplification and probe immobilization. They aimed to provide a low-cost solution suitable for both hospitals and low-resource settings. The researchers explored the use of aerosol jet printing to facilitate the fabrication of this integrated device. This study addresses the challenge of creating portable, sensitive, and easy-to-use diagnostic tools for viral detection.

The investigators utilized an aerosol jet printing approach to construct the integrated sensing platform. This design strategy avoids the necessity for complex probe immobilization on the sensor surface. The team employed a CRISPR-Cas13:guide-RNA complex to recognize the target viral genetic material. They monitored the collateral cleavage of ssRNA probes tagged with horseradish peroxidase. The researchers measured the resulting oxidation of 3,3',5,5'-tetramethylbenzidine through both color change and electrical current shifts. This protocol eliminates the requirement for traditional nucleic acid amplification procedures. The experimental setup facilitates operation at physiological temperatures to ensure compatibility with point-of-care requirements. The approach focuses on achieving high sensitivity while maintaining a simplified workflow for diagnostic applications.

The biosensor exhibits a detection sensitivity reaching the femtomolar range for viral RNA targets. The platform demonstrates a wide dynamic range spanning five orders of magnitude. The researchers observed that the presence of target RNA activates the CRISPR-Cas13 complex. This activation leads to the cleavage of ssRNA probes, which subsequently triggers the oxidation of the chemical substrate. The dual-function system successfully provides both colorimetric and electrochemical readouts. The team reports that the device functions without the need for complicated target amplification. The sensing protocol remains effective for rapid diagnostics in various testing environments. These findings highlight the capability of the printed sensor to detect pathogens with high precision.

The authors propose that their dual-function platform offers a viable solution for rapid viral detection. This system enables sensitive diagnostics without the requirement for complex target amplification steps. The researchers suggest that the device performs effectively across a wide dynamic range of five orders of magnitude. Their findings indicate that the integration of electrochemical and colorimetric signals enhances diagnostic reliability. The team claims that the aerosol jet printing approach facilitates low-cost manufacturing of these sensors. They conclude that the platform operates reliably at physiological temperatures for point-of-care applications. The study provides evidence that this method is suitable for use in both clinical and low-resource environments. These results support the potential utility of CRISPR-based biosensors for future pathogen screening efforts.