AuCu bimetal nanoclusters as high-performance mimics for ultrasensitive recognition of biomolecules

Abstract

Introducing novel mimic materials as alternatives for natural enzymes challenges the analysts. Study on the peroxidase-like materials is an active field in analytical research areas. Herein, Au/Cu bimetal nanoclusters (Au/Cu NCs) are introduced as highly efficient peroxidase mimics, which were investigated using fluorometric and colorimetric techniques. A comprehensive comparison between the catalytic activity of Au, Cu, and their bimetal NCs, with different ratios of Au/Cu was performed using some different peroxidase substrates (including 3,3′,5,5′-tetramethylbenzidine (TMB), o-phenylenediamine dihydrochloride (OPD), and terephthalic acid (TA)). Additionally, different capping agents were applied for the synthesis of NCs, and it was found that penicillamine-capped NCs with 50% Cu have higher activity than other synthesized NCs. Analytical application of the novel mimic for H2O2 detection caused a linear calibration in a wide linear range of 0.001–3 μmol/L, and a great detection limit (3S) of 0.18 nmol/L, using a sensitive fluorescence system. The developed system was also sensitive for recognizing glucose and cholesterol in blood samples, after their enzymatic oxidation and production of H2O2. Detection limits of 55 and 15 nmol/L were obtained for glucose and cholesterol, respectively. The presented method also showed good reliability, which was validated by certified reference materials.

Dopamine-Modified AuCu Bimetallic Nanoclusters as Charge Transfer-Based Biosensors for Highly Sensitive Glycine Detection

“…Furthermore, the as-prepared AuCu NCs showed excellent fluorescence stability compared with that of Au NCs and Cu NCs after 60 days (Figure S3c–e, Supporting Information). These results revealed that inserting Cu atoms into the Au NCs might alter their electronic properties, leading to modified fluorescence properties and high stability. , …”

“…These results revealed that inserting Cu atoms into the Au NCs might alter their electronic properties, leading to modified fluorescence properties and high stability. 30,32 3.2. Modification of the Surface of AuCu NCs with Dopamine.…”

“…10 Additionally, bimetallic AuCu NCs have been reported to possess greater peroxidase-like catalytic properties than those of pure Au NCs and Cu NCs. 32 The presence of AuCu NCs might promote the oxidation of DA to the quinone form, resulting in highly effective fluorescence quenching. This was supported by the results of comparative experiments, which revealed that the fluorescence quenching effect of DA on AuCu NCs was superior to those on Au NCs (K sv = 1.9 × 10 3 ) and Cu NCs (K sv = 1.3 × 10 3 ) (Figure S6, Supporting Information).…”

“…Under photoexcitation, an electron transfer process occurred from the nanoparticles to the quinone acceptor, causing fluorescence quenching . Additionally, bimetallic AuCu NCs have been reported to possess greater peroxidase-like catalytic properties than those of pure Au NCs and Cu NCs . The presence of AuCu NCs might promote the oxidation of DA to the quinone form, resulting in highly effective fluorescence quenching.…”

“…More recently, bimetallic NCs have attracted attention because introducing a different metal element into NCs can alter their electronic properties, leading to favorable fluorescence behavior, catalytic activity, and sensitivity. − Here, we fabricate and test dopamine-modified AuCu bimetallic NCs (AuCu NC–DA) as a charge transfer-based biosensor for glycine. The bimetallic AuCu NCs with an emission maximum at 400 nm are synthesized via a green method using bovine serum albumin (BSA) as a stabilizer. , The surface of the AuCu NCs is easily modified with DA without any complicated chemical reactions.…”