Sensitive detection of Campylobacter jejuni using one-step strategy based on functional nanospheres of immunomagnetic capture and quantum dots

Abstract

Campylobacter jejuni has emerged as the most common bacterial foodborne illness in the developed world. Here, we demonstrate a convenient one-step strategy for detecting C. jejuni. Immunomagnetic nanospheres (IMNS) and immunofluorescent nanospheres (IFNS, quantum dots) were used for the simultaneous, sensitive capture and recognition of C. jejuni. After magnetic separation with the IMNS, detection of C. jejuni was achieved with fluorescence measurement of the IFNS in the sandwich complexes (IMNS–bacteria–IFNS). The limit of detection of this assay was 103 CFU/mL, and the linear range was from 105 to 107 CFU/mL (R2 = 0.9994). When compared with a conventional two-step detection strategy, in which C. jejuni was first captured with the IMNS and then detected using the IFNS, this one-step detection strategy enhance sensitivity and save time. This suggested that the developed method has the potential for use as an alternative to the standard method for food quality assurance, as it provides rapid detection of C. jejuni in foodstuffs and the environment.