A 3D-Printed Integrated Handheld Biosensor for the Detection of .

() is one of the important seafood-borne pathogens that cause a serious gastrointestinal disorder in humans. Recently, biosensors have attracted serious attention for precisely detecting and tracking risk factors in foods. However, a major consideration when fabricating biosensors is to match the low cost of portable devices to broaden its application. In this study, a 3D-printed integrated handheld biosensor (IHB) that combines RPA-CRISPR/Cas12a, a lateral flow strip (LFS), and a handheld device was developed for the ultrasensitive detection of . Using the preamplification of RPA on gene of , a specific duplex DNA product was obtained to activate the trans-cleavage activity of CRISPR/Cas12a, which was then utilized to cleave the ssDNA probe. The ssDNA probe was then detected by the LFS, which was negatively correlated with the content of amplified RPA products of the gene. The IHB showed high selectivity and excellent sensitivity for detection, and the limit of detection was 4.9 CFU/mL. The IHB also demonstrated great promise for the screening of in samples and had the potential to be applied to the rapid screening of other pathogen risks for seafood and marine environmental safety.