Upshift of the d Band Center toward the Fermi Level for Promoting Silver Ion Release, Bacteria Inactivation, and Wound Healing of Alloy Silver Nanoparticles

Abstract

Silver (Ag)-based nanoparticles (NPs) with a high potential of Ag+ release have been known to be capable of promoting bacteria inactivation and the wound healing process; however, keeping a steady flux of high levels of Ag+ in Ag-based NPs is still challenging. Herein, a novel strategy in terms of altering the intrinsic electronic structure of Ag NPs was attempted to facilitate Ag oxidation and boost the Ag+ flux, as results of improved antibacterial and wound healing performance of Ag NPs. Gold (Au), platinum (Pt), and palladium (Pd) were doped into Ag NPs to tune their d band centers to upshift toward the Fermi level, and the formed Pd–Ag alloy NPs showed the largest shift, followed by Pt–Ag and Au–Ag NPs, as determined by density function theory calculation and ultraviolet photoemission spectroscopy measurement. Further X-ray photoelectron spectroscopy analysis indicates that a larger upshift could induce less electron filling in the antibonding orbital and a higher Ag oxidation level, leading to the more remarkable Ag+ release as determined by inductively coupled plasma optical emission spectrometry. All these alloy Ag NPs could more efficiently inhibit bacterial growth and accelerate the wound healing process than pure Ag NPs, and their antibacterial activity and wound healing performance were progressively proportional to the upshift values of the d band center. Taken together, tuning the d band center to upshift toward the Fermi level becomes a feasible strategy for designing therapeutic Ag-based NPs with a promising antibacterial and wound healing performance.

Antimicrobial efficacy of platinum‐doped silver nanoparticles

“…This antimicrobial activity directly corresponded to the dissolution rates of ionic silver, as well as the particle morphology (specific surface area). Therefore, it can be suggested that the antimicrobial efficacy of Pt‐AgNPs can be ascribed to the rapidly released silver ions due to the specific surface areas associated with the morphology of the nanoparticles (Breisch et al, 2019; Chang et al, 2019).…”

“…Furthermore, alloying with platinum did not enhance the antimicrobial activity of silver nanoparticles. However, it should be noted that platinum concentrations lower than 10 mol% were not investigated in these studies (Breisch et al, 2019; Chang et al, 2019).…”

“…Several studies have examined the combined effects of silver and platinum on antimicrobial efficacy (Breisch et al, 2019; Chang et al, 2019). Chang et al demonstrated that alloying AgNPs with approximately 11 mol% of gold, platinum, or palladium promoted the release of Ag + .…”

“…aureus and E . coli (Chang et al, 2019). In contrast, Breisch et al, studied the antimicrobial activity of bimetallic silver‐platinum nanoparticles with compositions ranging from 10 to 90 mol% platinum (Breisch et al, 2019).…”

Highly efficient preparation of Li2O breeder materials with core‐shell structure by oil‐based granulation route

“…The desired attributes of the product granules are controlled by the feed powder, liquid properties, type of granulator and the operating parameters. In the last 50 years, granulation has been widely used in specialty chemicals, pharmaceuticals, mineral processing, agricultural products and food 21‐23 . If the Li 2 O powder can be directly prepared into a uniform sphere by wet granulation, it will be of great significance for the development of the breeder blankets.…”