Ag/CdO NP-Engineered Magnetic Electrochemical Aptasensor for Prostatic Specific Antigen Detection

Abstract

A simple magnetic electrochemical aptasensor was established for the detection of prostatic specific antigen (PSA). Ag/CdO nanoparticles (NPs) were fabricated and exhibited strong electroreduction peaks at −1.07 V, attributing to the electron transfer from Cd2+ to Cd0 and the superior electron transportation of Ag. Aptamer-modified Ag/CdO NPs were assembled on the surface of superparamagnetic Fe3O4/graphene oxide nanosheets (GO/Fe3O4 NSs) through the hydrophobic and π–π stacking interaction of aptamers and GO NSs. These assemblies possessed superior electroactive properties, efficient electron transfer, and superparamagnetic response and could serve as sensing units for PSA detection with the aid of a magnetic electrode. With increasing concentrations of PSA, the high affinity of aptamers to PSA enabled the dissociation of Ag/CdO NPs from GO/Fe3O4 NSs, decreasing the intensity of electroreduction peaks. The Ag/CdO NP-engineered magnetic electrochemical aptasensor achieved sensitive and accurate detection of PSA in the range of 50 pg/mL to 50 ng/mL. The limit of detection (LOD) was as low as 28 pg/mL. This developed protocol can be extended to a large set of strong electroactive labels for reliable tumor biomarker detection with high sensitivity and specificity.

Behaviour of Regioisomeric Bithiophenes in the Oxidative Synthesis of Tetrathieno‐Fused π‐Expanded Fluorenes and Their Characterization

“…Changing the BrØnsted acid to Lewis acid (BF 3 .OEt 3 /Sc(OTf) 3 ) was not fruitful (Table 1, entries c,d). [19,20] Use of a relatively weaker oxidant chloranil (CA), [12b] under MsOH condition, gave 1 a in 80% yield for 1, while led to polymerization for 2 ( Table 1, entries e). It is interesting to notice the formation of product 1 a regioselectively from 1, under mild Scholl condition.…”

Conveniently Synthesized Butterfly‐Shaped Bitriphenylenes and their Application in Solution‐Processed Organic Field‐Effect Transistor Devices

“…The biphenyl/biaryl units in 8 – 11 are now appropriately positioned for oxidative Scholl cyclization to provide the desired conformationally‐locked π‐extended bitriphenylene analogs. Realizing the potential of FeCl 3 in producing the chlorinated side product (especially with 9 ), we opted for Rathore's mild oxidative cyclization procedure (DDQ/H + , Step 2, Scheme ) for the synthesis of 9–11 as reported by us earlier . This method gave us the desired dicyclized products 2–4 in excellent yields, without any side products .…”

Exhaustive Reduction of Esters Enabled by Nickel Catalysis

“…In contrast, the use of NiBr2•glyme/TMDSO/Mn in toluene-d8 resulted in an efficient 73% yield with >95%D incorporation (Scheme 4a). This procedure was found to be general, enabling the synthesis of several -CD3-containing molecules in good yield and high deuterium incorporation (41)(42)(43). Experiments in non-deuterated toluene gave ~5-10% reduced deuterium incorporation.…”