Synthesis of CaO₂ Nanocrystals and Their Spherical Aggregates with Uniform Sizes for Use as a Biodegradable Bacteriostatic Agent

Abstract

As a solid precursor to O2 and hydrogen peroxide (H2O2), calcium peroxide (CaO2) has found widespread use in applications related to disinfection and contaminant degradation. The lack of uniform nanoparticles, however, greatly limits the potential use of this material in other applications related to medicine. Here, a new route to the facile synthesis of CaO2 nanocrystals and their spherical aggregates with uniform, controllable sizes is reported. The synthesis involves the reaction between CaCl2 and H2O2 to generate CaO2 primary nanocrystals of 2–15 nm in size in ethanol, followed by their aggregation into uniform, spherical particles with the aid of poly(vinyl pyrrolidone) (PVP). The average diameter of the spherical aggregates can be easily tuned in the range of 15–100 nm by varying the concentrations of CaCl2 and/or PVP. For the spherical aggregates with a smaller size, they release H2O2 and O2 more quickly when exposed to water, resulting in superior antimicrobial activity. This study not only demonstrates a new route to the synthesis of uniform CaO2 nanocrystals and their spherical aggregates but also offers a promising bacteriostatic agent with biodegradability.

Facile Fabrication of Oxygen-Releasing Tannylated Calcium Peroxide Nanoparticles

“…CaO 2 hydrolyzes to generate H 2 O 2 and, subsequently, O 2 , when in contact with water, as shown in Equation (2) [ 12 ]. To determine the oxygen generation efficiency of TA/CaO 2 by hydrolysis, a fixed amount of each TA/CaO 2 sample was added to PBS (pH 7.4) and the amount of dissolved oxygen in the solution was measured ( Figure 4 ).…”

“…Moreover, the resultant products are non-uniform in size. To address these drawbacks, Shen et al reported an alternative method for the preparation of CaO 2 nanoparticles using polyvinyl pyrrolidine as a colloidal stabilizer [ 12 ].…”

Metal peroxides for cancer treatment

“…Based on the above theory, Xia et al reported an approach to synthesize CaO 2 nanocrystals and their spherical aggregates [ 41 ]. They chose ethanol as the solvent to reduce the hydrolysis of CaO 2 NPs.…”

Electrochemical Regulation of Antibacterial Activity Using Ferrocene-Containing Antibiotics

“…However, the widespread misuse of antibiotics in healthcare and agriculture causes noticeable resistance due to spontaneous bacterial mutation and horizontal gene transfer. [1][2][3] Although massive efforts have been done to counteract this resistance, such as unnecessary medication reduction, antibiotic combinations, and new antibiotics discoveries, [4][5][6][7] it is still challenging to completely avoid the emergence and spread of the resistance due to the strong adaptability of the bacteria. To prevent the resistance from evolving, there is an urgent need to develop unconventional strategies to control antibiotic functions and realize on-demand bacterial inhibition.…”