A sensitive and low-fouling aptasensor for alpha-fetoprotein (AFP) was developed based on mixed self-assembled aptamers and newly designed zwitterionic peptides, where densely immobilized peptides formed an antifouling layer to resist nonspecific protein adsorption, and sparsely attached aptamers acted as the recognizing layer to achieve target binding. The obtained biosensing interface responded to the target AFP with a strikingly selective and sensitive manner, exhibited excellent protein-resistant performance even in complex human serum solution, and showed promising feasibility for the quantitative analysis of AFP in real human serum samples.

No abstract

A general, efficient strategy for a self-powered PEC immunoassay with an evident photocurrent response was proposed by separating the photoanode from recognition events. The immunoassay demonstrates the exciting features of both high sensitivity and anti-interference capabilities.

An electrochemical biosensor for the detection of microRNA was prepared via chemical grafting of a Methylene Blue labeled reporter (MB-Rep) duplex onto a nanostructured surface that was obtained by electrodeposition of cobalt oxide and poly(o-phenylenediamine). This is followed by the attachment of hyaluronic acid and gold nanoclusters. In the presence of the target (microRNA), the probe-target duplex and the MB-Rep hairpin are formed. These will displace the labeled reporter from the sensor surface, and this results in a decrease of the amperometric signal for MB at a typical working voltage of -0.28 V (vs. Ag/AgCl). The electrode modified with hyaluronic acid possesses a large electroactive surface area and an excellent antifouling property. This makes it useful for ultrasensitive quantitation of microRNA even in complex biological media. The sensor has a linear response in the 100 f. to 0.1 μM microRNA concentration range, and a 33.3 f. detection limit. It was successfully applied to the determination of microRNA in cancer cells. Graphical abstract ᅟ.

The electrocatalytic oxidation of guanine in ssDNA at cobalt oxide nanoflower-modified aluminium electrode.