Fast infectious diseases diagnostics based on microfuidic biochip system

Molecular diagnostics is one of the most important tools currently in use for clinical pathogen detection due to its high sensitivity,specificity,and low consume of sample and reagent is keyword to low cost molecular diagnostics.In this paper,a sensitive DNA isothermal amplifi-cation method for fast clinical infectious diseases diagnostics at aM concentrations of DNA was developed using a polycarbonate(PC)microfuidic chip.A portable confocal optical fuo-rescence detector was specifically developed for the microfuidic chip that was capable of highly sensitive real-time detection of amplified products for sequence-specific molecular identification near the optical diffraction limit with low background.The molecular diagnostics of Listeria monocytogenes with nucleic acid extracted from stool samples was performed at a minimum DNA template concentration of 3.65 aM,and a detection limit of less than five copies of genomic DNA.Contrast to the general polymerase chain reaction(PCR)at eppendorf(EP)tube,the detection time in our developed method was reduced from 1.5h to 45 min for multi-target parallel detection,the consume of sample and reagent was dropped from 25μL to 1.45μL.This novel microfuidic chip system and method can be used to develop a micro total analysis system as a clinically relevant pathogen molecular diagnostics method via the amplification of targets,with potential applications in biotechnology,medicine,and clinical molecular diagnostics.

A flow chemiluminescence paper-based microfuidic device for detection of chromium(Ⅲ)in water

In this work,a solely gravity and capillary force-driven flow chemiluminescence(GCF-CL)paper-based microfuidic device has been proved for the first time as a new platforn for inex-pensive,usable,mini mally instrumented dynamic chemiluninescence(CL)detection of chromium(Ⅲ)[Cr(Ⅲ)],where an appropriate angle of inclination between the loading and detection zones on the paper produces a rapid flow of CL prompt solution through the paper charnel.For this study,we use a cost-effective paper device that is manufactured by a simple wax screen-printing method,while the signal generated from the Cr(Ⅲ)-catalyzed oxidation of luminol by H_(2)O_(2) is recorded by a low-cost and luggable CCD camera.A series of GCF-CL affecting factors have been evaluated carefully.At optimal conditions,two linear relationships between GCF-CL intensities and the logarithms of Cr(Ⅲ)concentrations are obtained in the concentration mnges of 0.025-35 mg/L and 50-500 mg/L separately,with the detection limit of 0.0245mg/L for a les than 30s assay,and relative standard deviations(RSDs)of 38%,4.5%and 2.3%for 0.75,5 and 50 mg/L of Cr(Ⅲ)(n=8).The above results indicate that the GCF-CL paper-based microfluidic device possesses a receivable sensitivity,dynamic range,storage stability and reproducibility.Finally,the developed GCF-CL is utilized for Cr(Ⅲ)detection in real water samples.