Microfluidic point-of-care testing device for multiplexed detection of liver function blood markers

In this work, we developed a novel microfluidic paper-based analytical device to quantify the blood markers of liver function from human fingertips and whole blood samples. The device can quickly acquire information for screening liver injury and supporting clinical decision-making by simultaneously performing quantitative tests for alanine aminotransferase, aspartate aminotransferase, and albumin. We evaluated the detection accuracy and the storage stability of the device using fingertip samples. The yielded results of our device correlated well with those from Mindray BS350s, even under the conditions of 35 °C and 90%RH. Thus, it offers an effective platform for clinical assessment of liver injury particularly in resource-limited areas.

An Electrochemical Immunosensor Based on a Self-Assembled Monolayer Modified Electrode for Label-Free Detection of α-Synuclein

This research demonstrated the development of a simple, cost-effective, and label-free immunosensor for the detection of α-synuclein (α-Syn) based on a cystamine (CYS) self-assembled monolayer (SAM) decorated fluorine-doped tin oxide (FTO) electrode. CYS-SAM was formed onto the FTO electrode by the adsorption of CYS molecules through the head sulfur groups. The free amine (–NH₂) groups at the tail of the CYS-SAM enabled the immobilization of anti-α-Syn-antibody, which concurrently allowed the formation of immunocomplex by covalent bonding with α-Syn-antigen. The variation of the concentrations of the attached α-Syn at the immunosensor probe induced the alternation of the current and the charge transfer resistance (R_ct) for the redox response of [Fe(CN)₆]^3−/4−, which displayed a linear dynamic range from 10 to 1000 ng/mL with a low detection limit (S/N = 3) of ca. 3.62 and 1.13 ng/mL in differential pulse voltammetry (DPV) and electrochemical impedance spectra (EIS) measurements, respectively. The immunosensor displayed good reproducibility, anti-interference ability, and good recoveries of α-Syn detection in diluted human serum samples. The proposed immunosensor is a promising platform to detect α-Syn for the early diagnose of Parkinson’s disease, which can be extended for the determination of other biologically important biomarkers.

A quantitative electrochemical assay for liver injury

Liver diseases represent a vastly underestimated and historically neglected public health problem, disproportionately affecting those in low- and middle- income countries (LMICs). Patients on hepatotoxic medications, such as HIV and TB medications, need consistent monitoring of liver function as part of their standard of care. In high resource settings, this is often the case, but in LMICs traditional methods fail due to high cost and lack of proper equipment, supplies and trained personnel. To address this gap in technology and patient care, we have developed a quantitative, electrochemical assay capable of quantifying levels of alanine aminotransferase (ALT), a primary biomarker associated with liver function. We can quantify ALT with increased sensitivity (1.53 nA/(U/L*mm²) and over a wide, linear concentration range (40-1990 U/L). The assay demonstrated in this study can be used to overcome several pressing challenges associated with effective, timely treatment of liver disease in LMICs.