Wallstent has been successfully used to open up clogged peripheral arteries. Co-Cr alloy is the preferred metal for the construction of wallstent. Unfortunately, major complications such as in-stent intimal hyperplasia,stent obstruction, and stent stricture are often reported, and these complications could be related to the metallic properties of the wallstent. In this study, the electrochemical properties of Co-Cr wires from wallstent were investigated using cyclic polarization, open-circuit potential, potentiostatic condition, and electrochemical impedance spectroscopy. Scanning electron microscopy and X-ray mapping were also employed to investigate the surface morphology and elemental distribution after electrochemical measurement. Results of this study showed the heterogeneous electrochemical properties of Co-Cr alloy wires that could result in severe galvanic corrosion of wallstent after implantation. Severe corrosion process could cause fracture of wallstent, resulting in localized inflammation, allergy, and thicker neointima.

Gold nanoclusters have revealed great potential as nanoantibiotics due to their superior chemical and physical characteristics. In this study, a peptide with 83 amino acids derived from haptoglobin was utilized as a surface ligand to synthesize gold nanoclusters via a facile hydrothermal approach. Characterization of the structural and optical properties demonstrated the successful synthesis of derived haptoglobin-conjugated gold nanoclusters. The spherical derived haptoglobin-conjugated gold nanoclusters exhibited a (111) plane of cubic gold and an ultra-small size of 3.6 ± 0.1 nm. The optical properties such as ultraviolet-visible absorption spectra, X-ray photoelectron spectroscopy spectra, fluorescence spectra, and Fourier transform infrared spectra also validated the successful conjugation between the derived haptoglobin peptide and the gold nanoclusters surface. The antibacterial activity, reactive oxygen species production, and antibacterial mechanisms of derived haptoglobin-conjugated gold nanoclusters were confirmed by culturing the bacterium Escherichia coli with hemoglobin to simulate bacteremia. The surface ligand of the derived haptoglobin peptide of derived haptoglobin-conjugated gold nanoclusters was able to conjugate with hemoglobin to inhibit the growth of Escherichia coli. The derived haptoglobin-conjugated gold nanoclusters with an ultra-small size also induced reactive oxygen species production, which resulted in the death of Escherichia coli. The superior antibacterial activity of derived haptoglobin-conjugated gold nanoclusters can be attributed to the synergistic effect of the surface ligand of the derived haptoglobin peptide and the ultra-small size. Our work demonstrated derived haptoglobin-conjugated gold nanoclusters as a promising nanoantibiotic for combating bacteremia.