Sensitive detection of thyroid stimulating hormone by inkjet printed microchip with a double signal amplification strategy

An electrochemical immunosensor for sensitive detection of thyroid stimulating hormone(TSH) has been developed by using an inkjet printed microchip and based on a double signal amplification strategy using magnetic beads(MBs), alkaline phosphatase(ALP) and p-aminophenyl phosphate(pAPP) reaction.Differential pulse voltammetry(DPV), cyclic voltammogram(CV) and amperometric i-t curve(i-t) were employed to characterize the immunosensor. High sensitivity and good selectivity were observed. The detection linear range was from 0.01 μIU/mL to 10 μIU/mL, in which the peak currents increased along with the concentration. The detection limit was 0.005 μIU/mL at S/N = 3. The immunosensor was also applied for TSH detection in human serum with recoveries from 98.0% to 101.8% and relative standard deviations from 1.3% to 3.1%, demonstrating potential value in clinical diagnosis.

In-situ monitoring of cell-secreted lactate by electrochemiluminescence sensing under biomimetic microfluidic confinement

Cell migration proceeds in 3D matrices in vivo,which can naturally switch to distinct phenotypes for bet-ter invasion in confined microenvironments.The studies of important metabolites under confinement are extremely meaningful for comprehensive insights into cancer metastasis.The integration of cell confine-ment device and analytical techniques is a key point for in-situ analysis of significant metabolites in vitro.Herein,an electrochemiluminescence(ECL)sensing platform was designed for in-situ monitoring of cell-secreted lactate in highly confined microenvironments.The 3-μm confiner was exactly fabricated via mi-crofabrication and microfluidics technique,and cells in high confinement and low adhesion tended to be round with contractile blebs on cell margins.Significantly,in-situ monitoring of lactate was successfully achieved on the ECL platform with the catalysis of lactate oxidase,in which the levels in different time intervals were acquired in the luminol-hydrogen peroxide system.Furthermore,the results were verified by the liquid chromatography-tandem mass spectrometry(LC-MS/MS)technology,which showed similar fluctuations with the ECL platform.This system offered an available avenue for metabolites analysis in highly confined microenvironments,which may advance deeper insights into metabolic mechanisms of cancer metastasis.