A portable device for probiotic counting and viability assessment based on microfluidic chip and image recognition

Probiotics play a critical role in maintaining or improving gut microbiome balance, offering numerous health benefits. Therefore, the accurate quantification of viable probiotics is essential for ensuring the efficacy of probiotic products. However, traditional culture-based methods are cumbersome and time-intensive, limiting their applications in scenarios requiring real-time decisions. Here, we report a portable, cost-effective system (approximately $2 per test, including reagents and one-time microfluidic chip usage) that enables rapid (3 min) on-site quantification of viable probiotics through a microfluidic chip integrated with a fluorescent biosensor and advanced image recognition technology. The system's reliability and accuracy were validated by comparison with the standard flow cytometry and plate counting, with results showing no significant differences in viable probiotics numbers. Furthermore, the platform demonstrated excellent specificity in distinguishing dead probiotics from viable ones with a large quantification range of 10⁷-10¹¹ colony-forming units (CFU) mL^-1, which encompasses the concentration range of commonly encountered probiotics, thereby meeting practical detection requirements. In summary, this portable system offers an innovative solution for rapid, on-site identification, and precise quantification of live and dead probiotics. Given these attributes, the system demonstrates significant commercial potential, particularly in situations requiring immediate results and efficient decision-making.