Ferrocene-Labelled Electroactive Aptamer-Based Sensors (Aptasensors) for Glycated Haemoglobin.

Glycated haemoglobin (HbA1c) is a diagnostic biomarker for type 2 diabetes. Traditional analytical methods for haemoglobin (Hb) detection rely on chromatography, which requires significant instrumentation and is labour-intensive; consequently, miniaturized devices that can rapidly sense HbA1c are urgently required. With this research, we report on an aptamer-based sensor (aptasensor) for the rapid and selective electrochemical detection of HbA1c. Aptamers that specifically bind HbA1c and Hb were modified with a sulfhydryl and ferrocene group at the 3' and 5'-end, respectively. The modified aptamers were coated through sulfhydryl-gold self-assembly onto screen printed electrodes, producing aptasensors with built in electroactivity. When haemoglobin was added to the electrodes, the current intensity of the ferrocene in the sensor system was reduced in a concentration-dependent manner as determined by differential pulse voltammetry. In addition, electrochemical impedance spectroscopy confirmed selective binding of the analytes to the aptamer-coated electrode. This research offers new insight into the development of portable electrochemical sensors for the detection of HbA1c.

Growth differentiation factor 15, ischemia modified albumin and pregnancy-associated plasma protein A in patients with coronary artery disease.

BACKGROUND: Growth differentiation factor 15 (GDF-15), ischemia modified albumin (IMA) might aid in the early diagnosis and risk stratification of patients with coronary artery disease (CAD), while pregnancy associated plasma protein-A (PAPP-A) can serve as a useful marker of vulnerable plaques and acute coronary syndrome (ACS). We sought to determine serum levels of GDF-15, IMA, PAPP-A and evaluate their diagnostic value in different types of CAD. METHODS: We detected serum levels of GDF-15, IMA and PAPP-A in 348 patients with CAD and 205 controls. Levels of high-sensitivity C reactive protein, creatine kinase isoenzyme MB, and high-sensitivity cardiac troponin-T, which represent biomarkers of inflammation, damage or necrosis, were also evaluated. RESULTS: There were significant differences of GDF-15, IMA and PAPP-A in patients with CAD compared with the controls, where GDF-15 seemed to be associated with severity of CAD. GDF-15 demonstrated a sensitivity of 84.0% and specificity of 84.8% for diagnosis of UAP, while the negative predictive value was 87.4%. The sensitivity and specificity, negative predictive value of IMA in the diagnosis of UAP were 70.0%, 69.5%, and 70.0%, respectively. PAPP-A had the lowest sensitivity and negative predictive value compared with other markers. CONCLUSIONS: GDF-15 demonstrated a significant improvement in earlier prediction and assessment of overall patient risk of UAP comparing to IMA and PAPP-A.