Hydrogel-enzyme micropatch array format for chemical mapping: A proof of concept

Area of Science:

• Biomedical Engineering
• Chemical Sensing
• Materials Science

Background:

• Conventional methods offer limited spatial information on analyte distribution.
• Substance distributions on surfaces often display complex inhomogeneities.
• Accurate mapping of chemical distributions is crucial across various scientific fields.

Purpose of the Study:

• To develop a novel enzyme-loaded hydrogel array biosensor for high-resolution chemical mapping.
• To overcome the limitations of single-point or averaged analyte concentration measurements.
• To provide snapshots of chemical distributions on surfaces.

Main Methods:

• Development of 5x5 and 10x10 enzyme-loaded hydrogel arrays.
• Utilizing agarose hydrogel containing enzymes and substrates within an acrylic array base.
• Employing a custom-built array reader with LED illumination, a miniature camera, and Raspberry Pi for image acquisition and analysis.
• Optimization of parameters including contact time, agarose concentration, substrate and enzyme concentrations.

Main Results:

• Successful optimization of the hydrogel array biosensor for mapping glucose and lactic acid.
• Demonstrated capability to map glucose distribution in fruits/vegetables (apple, guava, cucumber).
• Successfully mapped lactic acid distribution in cheese samples.

Conclusions:

• The developed hydrogel-based chemical mapping method provides detailed spatial information on analyte distributions.
• This biosensor technology offers a significant advancement over conventional sensing approaches.
• Potential applications span food science, plant physiology, clinical chemistry, and forensics for surface analyte assessment.