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Salmonella screening is essential to avoid food poisoning. A simple, fast and sensitive colorimetric biosensor was elaborately developed for Salmonella detection on a microfluidic chip through limiting air chambers for precise air control, switching rotary valves for accurate fluid selection, a convergence-and-divergence passive micromixer and an extrusion-and-suction active micromixer for efficient fluid mixing, and immune gold@platinum palladium nanocatalysts for effective signal amplification. The mixture of bacteria, immune magnetic nanobeads and nanocatalysts was first rapidly mixed to form nanobead-bacteria-nanocatalyst conjugates and magnetically separated for enrichment. After washing with water, the conjugates were used to catalyze colorless substrate and blue product was finally analyzed using ImageJ for quantifying bacterial concentration. The finger-actuated microfluidic chip enabled designated control of designated fluids in designated places towards designated directions by simple press-release operations on designated air chambers without any external power. Under optimal conditions, this sensor could detect Salmonella at 45 CFU/mL in 25 min.
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http://dx.doi.org/10.1016/j.foodchem.2024.140488 | DOI Listing |
Proc Natl Acad Sci U S A
September 2025
Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202.
Retinal ganglion cells (RGCs) are highly compartmentalized neurons whose long axons serve as the sole connection between the eye and the brain. In both injury and disease, RGC degeneration occurs in a similarly compartmentalized manner, with distinct molecular and cellular responses in the axonal and somatodendritic regions. The goal of this study was to establish a microfluidic-based platform to investigate RGC compartmentalization in both health and disease states.
View Article and Find Full Text PDFAnal Sci
September 2025
Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan.
Surface-enhanced Raman scattering (SERS) is a powerful analytical technique; however, its quantitative application has been limited by the instability of substrates and significant signal fluctuations. In this study, we demonstrated that 4-aminobenzenethiol (4-ATP) can be quantitatively detected through statistical analysis of SERS signal intensity distributions obtained using citrate-stabilized AuNPs, biotin-functionalized AuNPs, and gold nanoparticle (AuNP)-bound polystyrene (PS) microparticles. Raman spectra obtained in bulk aqueous solution under static conditions showed that the detection sensitivity of 4-ATP using AuNP-bound PS microparticles was approximately twice that achieved with citrate-stabilized AuNPs or biotin-modified AuNPs.
View Article and Find Full Text PDFLab Chip
September 2025
Institute of Integrated Research, Institute of Science Tokyo, R2-9, 4259 Nagatsuta-cho, Midoriku, Yokohama, Kanagawa 226-8501, Japan.
Tunability in isolating target cells of varying sizes from complex heterogeneous samples is essential for biomedical research and diagnostics. However, conventional deterministic lateral displacement (DLD) systems lack flexibility due to their fixed critical diameters (). Here, we present a thermo-responsive DLD micropillar array that enables tunable cell separation by dynamically modulating through temperature control.
View Article and Find Full Text PDFPLoS One
September 2025
Department of Information Technology, Uppsala University, Uppsala, Sweden.
For effective treatment of bacterial infections, it is essential to identify the species causing the infection as early as possible. Current methods typically require hours of overnight culturing of a bacterial sample and a larger quantity of cells to function effectively. This study uses one-hour phase-contrast time-lapses of single-cell bacterial growth collected from microfluidic chip traps, also known as a "mother machine".
View Article and Find Full Text PDFAnal Chem
September 2025
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China.
High-fat foods are decomposed into fatty acids during digestion and absorption, primarily occurring in the gastrointestinal tract, and numerous studies have indicated that long-term high-fat diets significantly increase the incidence of intestinal disorders. As a critical intestinal hormone, serotonin (5-hydroxytryptamine, 5-HT) is involved in regulating intestinal peristalsis, secretion, and visceral sensitivity. However, due to the lack of methods capable of reproducing intestinal mechanical activities and in situ monitoring of 5-HT levels, the influence of high-fat diets on intestinal 5-HT release remains unclear.
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