Biothiols as Chelators for Preparation of N-(aminobutyl)-N-(ethylisoluminol)/Cu²⁺ Complexes Bifunctionalized Gold Nanoparticles and Sensitive Sensing of Pyrophosphate Ion

Abstract

In this work, chemiluminescence (CL) reagent and catalyst metal ion complexes bifunctionalized gold nanoparticles (BF-AuNPs) with high CL efficiency were synthesized via an improved synthesis strategy. Biothiols, such as cysteine (Cys), cysteinyl-glycine (Cys-Gly), homocysteine (Hcy), and glutathione (GSH), instead of 2-[bis[2-[carboxymethyl-[2-oxo-2-(2-sulfanylethylamino)ethyl]amino]ethyl]amino]acetic acid (DTDTPA), were used as new chelators. N-(aminobutyl)-N-(ethylisoluminol) (ABEI) was used as a model of CL reagents and Cu(2+) as a model of metal ion. In this strategy, biothiols were first grafted on the surface of ABEI-AuNPs by Au-S bond. Then, Cu(2+) was captured onto the surface of ABEI-AuNPs by the coordination reaction to form BF-AuNPs. The CL intensity of Cu(2+)-Cys/ABEI-AuNPs was 1 order of magnitude higher than that of DTDTPA/Cu(2+)-ABEI-AuNPs synthesized by the previous work. Moreover, strong CL emission of Cu(2+)-Cys/ABEI-AuNPs was also observed in neutral pH conditions. In addition, the present BF-AuNPs synthesis method exhibited advantages over the previous method in CL efficiency, simplicity, and synthetic rate. Finally, by virtue of Cu(2+)-Cys/ABEI-AuNPs as a platform, a simple CL chemosensor for the sensitive and selective detection of pyrophosphate ion (PPi) was established based on the competitive coordination interactions of Cu(2+) between Cys and PPi. The method exhibited a wide detection range from 10 nM to 100 μM, with a low detection limit of 3.6 nM. The chemosensor was successfully applied to the detection of PPi in human plasma samples. It is of great application potential in clinical analysis. This work reveals that BF-AuNPs could be used as ideal nanointerface for the development of novel analytical methods.

Highly Chemiluminescent Magnetic Beads for Label-Free Sensing of 2,4,6-Trinitrotoluene

“…They often need to construct a CL interface to produce analytical signal. Earlier work demonstrated that CL functionalized nanomaterials such as CL reagent/metal ion (catalyst) bifunctionalized gold nanoparticles, , graphene oxide, and multiwalled carbon nanotubes are good interfaces for label-free bioassays. However, in most of cases, such CL functionalized nanomaterials need to be further immobilized on a carrier such as a microplate and an electrode to construct a CL interface for label-free bioassays so that the separation can be carried out after they react with recognition biomolecules and analytes in samples.…”

Research Progress in the Sensing Ensembles for Pyrophosphate

“…另外, 生物流体中 ATP, AMP, ADP 等干扰离子的 含量大约在 nmol•L -1 数量级, 要比 PPi 含量低, 而 Pi 却比 PPi 含量高 [29] . Cui 等 [37] Figure 7 Chemiluminescence sensing emsemble for PPi based on the mechanism of competitive coordination 等离子增强的荧光技术能够明显放大荧光信号, 提 高检测灵敏度 [38] . Ouyang 等 [45,46] .…”

Assembly of Multifunctionalized Gold Nanoparticles with Chemiluminescent, Catalytic, and Immune Activity for Label-Free Immunoassays

“…Recently, much attention has been paid to chemiluminescent (CL) functionalized nanomaterials, especially gold nanoparticles, in bioassays due to their good CL property, ease of self-assembly and good biocompatibility. − At the beginning, luminol-type CL reagent functionalized gold nanoparticles (CF-GNPs) were synthesized using direct reduction methods. , CL reagent molecules were used to reduce HAuCl 4 to obtain GNPs and acted as stabilizers to be coated on the surfaces of GNPs. CF-GNPs with good CL activities as analytical probes and interfaces have been successfully applied to immunoassays and DNA assays. − Afterward, to develop CF-GNPs with high CL efficiency, catalysts metal ions were further coated onto the surfaces of GNPs with the help of chelators to form gold nanoparticles bifunctionalized by CL molecules and metal complexes (BF-GNPs) with excellent CL efficiency. , However, it is very challenging to connect BF-GNPs with recognition elements like antibodies, aptamers, and DNA because of the high surface coverage fraction of BF-GNPs, limiting their applications in bioassays. Therefore, we wonder if it is possible to directly assemble catalysts metal ions onto the surfaces of antibody conjugated CF-GNPs to obtain an ideal analytical interface with high CL efficiency during the fabrication of immunosensors by virtue of blocker bovine serum albumin (BSA), since BSA contains amino and carboxyl groups and is ready to coordinate with metal ions, avoiding the use of additional chelators.…”

“…10−12 Afterward, to develop CF-GNPs with high CL efficiency, catalysts metal ions were further coated onto the surfaces of GNPs with the help of chelators to form gold nanoparticles bifunctionalized by CL molecules and metal complexes (BF-GNPs) with excellent CL efficiency. 13,14 However, it is very challenging to connect BF-GNPs with recognition elements like antibodies, aptamers, and DNA because of the high surface coverage fraction of BF-GNPs, limiting their applications in bioassays. Therefore, we wonder if it is possible to directly assemble catalysts metal ions onto the surfaces of antibody conjugated CF-GNPs to obtain an ideal analytical interface with high CL efficiency during the fabrication of immunosensors by virtue of blocker bovine serum albumin (BSA), since BSA contains amino and carboxyl groups and is ready to coordinate with metal ions, avoiding the use of additional chelators.…”