Graphene field effect transistor biosensor realizes highly sensitive detection of lactose

To ensure the safety of lactose-free products and a healthy diet for patients with lactose intolerance, the determination of lactose in foods and beverages is very important.

The methods for detecting lactose mainly include gas chromatography, ultra-high performance liquid chromatography-tandem mass spectrometry, and nuclear magnetic resonance. However, most of these methods require expensive equipment and complicated sampling procedures, so the development and operation of convenient, highly sensitive lactose detection technology has become the focus of this field.

Therefore, Japanese scientists have prepared a field-effect tube (FET) biosensor based on gold nanoparticle-modified graphene, which can detect low-concentration lactose with high sensitivity and has great clinical application value.

This graphene device is functionalized with a carbohydrate recognition domain (CRD) of the human galectin-3 (hGal-3) protein to detect the presence of lactose from the donor effect of lectin - glycan affinity binding on the graphene. Although the detection of lactose is important because of its ubiquitous presence in food and for disease related applications (lactose intolerance condition), in this work we exploit the lectin/carbohydrate interaction to develop a device that in principle could specifically detect very low concentrations of any carbohydrate. The biosensor achieved an effective response to lactose concentrations over a dynamic range from 1 fM to 1 pM (10⁻¹⁵ to 10⁻¹² mol L^-1) with a detection limit of 200 aM, a significant enhancement over previous electrochemical graphene devices.

This study shows that the combined sensor of lectin and graphene FET (G-FET) has the potential to detect carbohydrates with high sensitivity and specificity in disease diagnosis, and will play an important role in clinical disease diagnosis.

Reference: Eric Danielson, et al. Non-enzymatic and highly sensitive lactose detection utilizing graphene field-effect transistors. Biosensors and Bioelectronics, 2020.DOI: 10.1016/j.bios.2020.112419