Fabrication of avidin-stabilized gold nanoclusters with dual emissions and their application in biosensing

Abstract

Protein-stabilized gold nanoclusters (Prot-Au NCs) have been widely used in biosensing and cell imaging owing to their excellent optical properties and low biotoxicity. However, several Prot-Au NCs reported in the literature do not retain the biological role of the protein, which greatly limits their ability to directly detect biomarkers. This study demonstrated for the first time the successful synthesis of dual-function avidin-stabilized gold nanoclusters (Av–Au NCs) using a one-pot method. The resulting Av–Au NCs exhibited intense blue and red emissions under 374 nm excitation. Furthermore, the Av–Au NCs retained the native functionality of avidin to bind to biotin. When DNA strands modified with biotin at both ends (i.e., linker chains) were mixed with Av–Au NCs, large polymers were formed, indicating that Av–Au NCs could achieve fluorescence signal amplification by interacting with biotin. Taking advantage of the aforementioned properties, we constructed a novel enzyme-free fluorescent biosensor based on the Av–Au NCs-biotin system to detect DNA. The designed fluorescent biosensor could detect target DNA down to 0.043 nM, with a wide line range from 0.2 nM to 20 µM. Thus, these dual-functional Av–Au NCs were shown to be an excellent fluorescent material for biosensing. Graphic abstract

Horseradish peroxidase-catalyzed polyacrylamide gels: monitoring their polymerization with BSA-stabilized gold nanoclusters and their functional validation in electrophoresis

“…This might be due to the Au atoms were mainly present in the form of Au clusters, which was consistent with previous literature. 53 These results provided evidence of the successful synthesis of BSA-Au NCs.…”

Preclinical safety assessment of photoluminescent metal quantum clusters stabilized with autologous serum proteins for host specific theranostics

“…The Au4f spectra was deconvoluted to reveal Au4f 7/2 peaks centred at 85.81 eV and 86.5 eV corresponding to Au 0 and Au +1 which are higher than reported for BSA- AuQCs 1 . This might be attributed to the fact that QCNS contain several smaller clusters 39 . This confirms that QCNS possess the classical core & shell architecture of Au & Au-thiol which is typical of AuQCs.…”

“…The TCSPC analysis was carried out after dispersing QCNS in ultrapure water. Since the lifetimes were observed to be on the microsecond scale, the emission was predominantly due to phosphorescence 39 . Further, the basic optical properties of both Human derived QCNS (H-QCNS) and Murine derived QCNS (M-QCNS) were also found to be comparable ( Fig.…”

Protein-Directed Au(0)-Rich Gold Nanoclusters as Ratiometric Luminescence Sensors for Auric Ions via Comproportionation-Induced Emission Enhancement

“…However, different from traditional mono- or bi-dentate ligands of small organic molecules, biomolecular protein templates recently have been used to develop novel, multidentate polymers as Au NC ligands. , This allows the space-confinement effect to control the Au seed growth instead of common dynamics control over the reduction process of Au NCs by small molecules. A variety of natural proteins have been explored and exploited to direct and template in situ synthesis of Au NCs. − The introduction of synthetic biology has also allowed for Au NC protein templates to be designed to produce Au NCs with highly specific properties. , The protein-protected Au NCs are easy to be modified and biologically compatible. Their luminescence is stable against photobleaching and has a large Stokes-shift.…”