Cucurbituril Enhanced Electrochemiluminescence of Gold Nanoclusters via Host-Guest Recognition for Sensitive D-Dimer Sensing.

Gold nanoclusters (AuNCs) are promising electrochemiluminescence (ECL) signal probes for their outstanding biocompatibility, unusual molecule-like structures, and versatile optical and electrochemical properties. Nevertheless, their relatively low ECL efficiency and poor stability in aqueous solutions hindered their application in the ECL sensing field. Herein, a facile host-guest recognition strategy was proposed to enhance the ECL efficiency and stability of Au NCs by rigidifying the surface of ligand-stabilized AuNCs via supramolecular self-assembly between cucurbiturils[7] (CB[7]) and l-phenylalanine (l-Phe). Meanwhile, mercaptopropionic acid (MPA) was introduced as a ligand in order to cooperatively enhance the performance of the AuNCs and facilitate the link between AuNCs and bioactive substances. The prepared CB[7]/l-Phe/MPA-AuNCs had a higher ECL emission efficiency, achieving about 2-fold stronger ECL intensity than that of l-Phe/MPA-AuNCs. In addition, after non-covalent modification with CB[7], the finite stability of the papered AuNCs was significantly improved. The prepared CB[7]/l-Phe/MPA-AuNCs showed excellent D-dimer sensing results, exhibiting a linear range from 50.00 fg/mL to 100.0 ng/mL and a detection limit of 29.20 fg/mL (S/N = 3). Our work demonstrated that the host-guest self-assembly strategy provided a universal approach for strengthening the ECL efficiency and stability of nanostructures on an ultra-small scale.

Bimetallic Metal-Organic Frameworks as an Efficient Capture Probe in Signal On-Off-On Electrochemiluminescence Aptasensor for Microcystin-LR Detection.

To ensure drinking water quality, the development of rapid and accurate analytical methods is essential. Herein, a highly sensitive electrochemiluminescence (ECL) aptasensor-based on the signal on-off-on strategy was developed to detect the water pollutant microcystin-LR (MC-LR). This strategy was based on a newly prepared ruthenium-copper metal-organic framework (RuCu MOF) as the ECL signal-transmitting probe and three types of PdPt alloy core-shell nanocrystals with different crystal structures as signal-off probes. Compounding the copper-based MOF (Cu-MOF) precursor with ruthenium bipyridyl at room temperature facilitated the retention of the intrinsic crystallinity and high porosity of the MOFs as well as afforded excellent ECL performance. Since bipyridine ruthenium in RuCu MOFs could transfer energies to the organic ligand (H3BTC), the ultra-efficient ligand luminescent ECL signal probe was finally obtained, which greatly improved the sensitivity of the aptasensor. To further improve the sensitivity of the aptasensor, the quenching effects of noble metal nanoalloy particles with different crystal states were investigated, which contained PdPt octahedral (PdPtOct), PdPt rhombic dodecahedral (PdPtRD), and PdPt nanocube (PdPtNC). Among them, the PdPtRD nanocrystal exhibited higher activity and excellent durability, stemming from the charge redistribution caused by the hybridization of Pt and Pd atoms. Moreover, PdPtRD could also load more -NH2-DNA strands because it exposed more active sites with a large specific surface area. The fabricated aptasensor exhibited outstanding sensitivity and stability in MC-LR detection, with a linear detection range of 0.0001-50 ng mL-1. This study provides valuable directions for the application of alloy nanoparticles of noble metals and bimetallic MOFs in the field of ECL immunoassay.

A biocompatible surface display approach in Shewanella promotes current output efficiency.

The biology-material hybrid method for chemical-electricity conversion via microbial fuel cells (MFCs) has garnered significant attention in addressing global energy and environmental challenges. However, the efficiency of these systems remains unsatisfactory due to the complex manufacturing process and limited biocompatibility. To overcome these challenges, here, we developed a simple bio-inorganic hybrid system for bioelectricity generation in Shewanella oneidensis (S. oneidensis) MR-1. A biocompatible surface display approach was designed, and silver-binding peptide AgBP2 was expressed on the cell surface. Notably, the engineered Shewanella showed a higher electrochemical sensitivity to Ag+, and a 60 % increase in power density was achieved even at a low concentration of 10 µM Ag+. Further analysis revealed significant upregulations of cell surface negative charge intensity, ATP metabolism, and reducing equivalent (NADH/NAD+) ratio in the engineered S. oneidensis-Ag nanoparticles biohybrid. This work not only provides a novel insight for electrochemical biosensors to detect metal ions, but also offers an alternative biocompatible surface display approach by combining compatible biomaterials with electricity-converting bacteria for advancements in biohybrid MFCs.

Identification of heptapeptides interacting with IFN-α-sensitive CML cells.

BACKGROUND: Interferon-alpha (IFN-α) is the traditional therapeutic agent for chronic myeloid leukemia (CML). The molecular mechanism of IFN-α efficacy in the treatment of CML is not fully clear. OBJECTIVES: To identify the peptides and/or proteins that bind to the proteins specifically expressed on the surface of IFN-α-sensitive CML cells by using a phage display library. DESIGN/METHODS: IFN-α-sensitive KT-1/A3 cells were used as the target, and IFN-α-resistant subline KT-1/A3R was used as absorber for phage display biopanning. The positive phage clones were identified by enzyme-linked immunosorbent assay and flow cytometry. The peptides were deduced from their DNA sequences. RESULTS: Multiple clones showed high binding efficiency to KT-1/A3 cells compared with that of the other leukemia cells. One of the peptides, KLWVIPQ, has a partial amino acid sequence homology with the C-terminal domain of E3 ubiquitin-protein ligase. CONCLUSIONS: This study presents the identification of specific heptapeptides that bind to IFN-α-sensitive KT-1/A3 cells. The cancer-selective ligands provide novel strategies for early and differential diagnoses, as well as potential targeted drug delivery.