Harnessing gold nanomaterials for advanced multicolor colorimetric biosensors in food hazards detection

Hazards such as pathogenic bacteria, mycotoxins, pesticides, antibiotics, heavy metal ions, etc., cause serious food safety problems worldwide due to their toxicity and frequent contamination. Rapid screening is an effective way for food safety control, which highly relies on the development of sensitive, specific, and convenient detection methods. The multicolor colorimetric biosensors based on gold nanomaterials have evolved into advanced tools for detecting various hazards in food, with intuitive readout. The excellent localized surface plasmon resonance (LSPR) properties of gold nanomaterials enable them to exhibit bright colors when used as chromophores. In addition, the small changes in the morphology of gold nanomaterials can lead to significant changes in the wavelength of the LSPR peak, resulting in vivid color changes. Since the color discrimination ability of the normal human eye is usually superior to the intensity change ability, the way in which different concentrations of targets represent vivid color changes makes it feasible to fabricate sensors with improved accuracy in visual semi-quantitative detection. By combining with various signal amplification strategies, the detection sensitivity of the constructed sensors can be further improved, even reaching the level of pg/mL. In this review, two strategies for changing the morphology of gold nanomaterials in constructing multicolor colorimetric biosensors, namely the etching strategy and the growth strategy were discussed. We also highlight current progress in developing different gold nanomaterial-based multicolor colorimetric biosensors for detecting various hazards in food. The hazards in food samples are classified as pathogens, mycotoxins, indicators of food freshness, pesticides, antibiotics, heavy metal ions, food additives, and hazards from food processing and packaging. The multicolor colorimetric biosensors based on gold nanomaterials represent a promising tool for visual detection of hazardous materials in food.