Quantitative gold nanorods based photothermal biosensor for glucose using a thermometer as readout

Area of Science:

• Nanomaterials Science
• Biosensors
• Analytical Chemistry

Background:

• Point-of-care testing (POCT) requires simple and portable readout strategies.
• Thermometers offer accurate and straightforward detection for POCT development.
• Developing new thermometer-based detection methods is crucial for advancing diagnostics.

Purpose of the Study:

• To develop a simple glucose biosensor using gold nanorods and a thermometer.
• To leverage the photothermal effect of gold nanorods for glucose detection.
• To establish a portable and accurate method for glucose monitoring.

Main Methods:

• Gold nanorods (AuNRs) were synthesized and their aspect ratios were modified.
• Glucose oxidase catalyzed the reaction of glucose with oxygen to produce hydrogen peroxide (H2O2).
• Fe2+ mediated the etching of AuNRs by H2O2, altering their optical properties and photothermal effect.

Main Results:

• The etching of AuNRs caused a blue-shift in their localized surface plasmon resonance peak.
• This shift reduced the photothermal effect, leading to a measurable decrease in system temperature.
• A linear relationship was observed between temperature change and the logarithm of glucose concentration (1.0-10.0 mM), with a 0.8 mM detection limit.

Conclusions:

• The developed biosensor provides a simple, thermometer-readout method for glucose detection.
• The method demonstrates good accuracy, with a bias offset of -0.03 mM compared to hospital methods.
• The principle is adaptable for detecting other analytes by changing the enzyme, highlighting its versatility.