Gold nanoparticle chemiresistors operating in biological fluids

Area of Science:

• Nanotechnology
• Biosensing
• Analytical Chemistry

Background:

• Gold nanoparticle (Au(NP)) chemiresistors face limitations in biological fluids due to protein and lipid fouling.
• Matrix effects from biomolecules deactivate sensing mechanisms, hindering direct application in biofluids.

Purpose of the Study:

• To investigate ultrafiltration membranes as protective barriers against biomolecular fouling for Au(NP) chemiresistors.
• To enable direct sensing of small organic molecules in protein-loaded biological fluids.
• To demonstrate the potential for Au(NP) chemiresistor arrays in food and health applications.

Main Methods:

• Utilized ultrafiltration membranes with varying molecular weight cut-offs (MWCO) to shield Au(NP) chemiresistors.
• Tested sensor performance in protein-loaded biofluids with small molecule titrations (e.g., toluene).
• Developed a sensor array of functionalized Au(NP) chemiresistors protected by a size-selective membrane for milk spoilage detection.

Main Results:

• All investigated ultrafiltration membranes effectively prevented fouling of Au(NP) chemiresistors by globular biomolecules.
• A 10 kDa MWCO membrane demonstrated optimal performance in biofluid environments.
• Successful detection and discrimination of pasteurised bovine milk spoilage were achieved using the membrane-protected sensor array.
• On-chip protein separation and small metabolite detection capabilities were demonstrated.

Conclusions:

• Ultrafiltration membranes provide effective protection against protein fouling for Au(NP) chemiresistors in biological fluids.
• This membrane-based approach significantly expands the application scope of Au(NP) chemiresistors.
• The technology holds potential for microbial metabolomics, food industry quality control, and health services diagnostics.