A substantial outstanding challenge in diagnostics and disease monitoring is an ability to rapidly and conveniently assay for protein biomarkers within complex biological media. Label-free electroanalytical methods present, arguably, the most promising and scalable means of achieving this but, as with all label-free assays, can struggle with response selectivity issues that arise from nonspecific surface interactions. Impedimetric methods are ultrasensitive and have been applied to the quantification of a wide range of proteins but have not previously been utilized in a multiplexed format capable of operation in complex analytical fluid. Herein, we present the use of thermally cross-linked poly(ethylene glycol) (PEG) polymer sensory array interfaces in the ultrasensitive quantification of two protein markers, insulin and C-reactive protein (CRP). This was achieved with detection limits of 171 ± 19 fM and 150 ± 10 pM, respectively. Significantly, the arrays not only enable the simultaneous, fast, nonamplified, and label-free detection of both markers without reagent addition but do so with little cross talk, even in human serum. A blind analysis of 17 real patient samples generated results in excellent agreement with those obtained through a clinically approved chemiluminescence assay.
Aims/IntroductionHomocysteine levels during pregnancy in women with gestational diabetes mellitus (GDM) have been studied; however, it remains unclear whether hyperhomocysteinemia is a useful predictor of insulin resistance. The present study aimed to evaluate the relationship between homocysteine level and GDM.Materials and MethodsPubMed, Elsevier, Web of Science and CNKI were searched for relevant studies published up to January 2015. Manual searches of references of the relevant original studies were carried out. Meta‐analysis was used to assessed the relationship between homocysteine level and GDM using the stata 12.0 software.ResultsHomocysteine levels were significantly elevated in women with GDM compared with those without GDM (weighted mean difference 0.77, 95% confidence interval 0.44–1.10). This evidence was more consistent during the second trimester measurement of homocysteine (weighted mean difference 0.95, 95% confidence interval 0.67–1.23) and for women aged older than 30 years (weighted mean difference 0.90, 95% confidence interval 0.63–1.17).ConclusionsThe present meta‐analysis shows that homocysteine level is significantly elevated among women with GDM compared with women with normal glucose tolerance, and this finding persists more during the second trimester.
Diagnostic tests currently underpin the majority of patient management decisions and biosensing devices capable of reporting on levels of specific analytes in blood, urine or saliva have already had a profound impact on clinical diagnostics and the quality of life of those unfortunate enough to live with, or be exposed to, disease. Among the range of methodologies available to protein biomarker detection, those based on electroanalysis present the most promising combination of sensitivity, low cost, speed, convenience and multiplexing. To date, a plethora of impedance based assays have been developed for the detection of disease‐associated biomarkers through the employment of a range of planar or “nanofunctionalized” interfaces comprising immobilized antibodies/antigens, oligonucleotide or PNA receptors. This review selectively highlights recent advances in this area.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.