Advances of nanobody-based immunosensors for detecting food contaminants

Abstract

Background

Immunoassays are reliable and convenient approaches to realizing the sensitive detection of ultralow levels of analytes (contaminants, allergens, biotoxins, etc.). Antibodies are the core element of constructed immunoassays in assuring their specificity and sensitivity toward target-of-interest. However, conventional antibodies are challenged by instability against environmental variables and economic burdens during their large-scale production. Alternatively, nanobodies are emerging as substitutable biorecognition elements in realizing the detection of food contaminants, exhibiting superior specificity and sensitivity.

Scope and approach

This review provides an up-to-date introduction to nanobody-based immunosensors for sensitively detecting the different contaminants in food matrices. The existing nanobodies that have been screened and employed in the establishment of immunoassays, along with the genetic modification strategies for achieving higher affinity and sensitivity, are summarized. Furthermore, the multifunctionalities of nanobodies in the immunoassays, namely analyte catcher, helper for signal tracer, alternator for surrogate antigen, and selector for mimotope, are introduced. Additionally, the applications of nanobody-derived immunosensors in detecting mycotoxins, pesticides, biotoxins, and allergens are highlighted. The insights to address the current challenges that hamper the broader application of nanobodies in immunosensing applications are provided.

Key findings and conclusions

Nanobodies are promising alternatives to conventional antibodies in terms of stability, flexible genetic engineering, solubility, cost-effectiveness, etc. The ongoing effects of tuning the sequence composition and configuration of novel nanobodies, controlling the spatial arrangement of nanobodies following their conjugation on the scaffolds, and designing portable devices to realize the on-site detection are expected to pave the way for nanobody-based immunosensors in the detection of various food contaminants.