Nanosynthesis of Silver-Calcium Glycerophosphate: Promising Association against Oral Pathogens

Abstract

Nanobiomaterials combining remineralization and antimicrobial abilities would bring important benefits to control dental caries. This study aimed to produce nanocompounds containing calcium glycerophosphate (CaGP) and silver nanoparticles (AgNP) by varying the reducing agent of silver nitrate (sodium borohydride (B) or sodium citrate (C)), the concentration of silver (1% or 10%), and the CaGP forms (nano or commercial), and analyze its characterization and antimicrobial activity against ATCC Candida albicans (10231) and Streptococcus mutans (25175) by the microdilution method. Controls of AgNP were produced and silver ions (Ag+) were quantified in all of the samples. X-ray diffraction, UV-Vis, and scanning electron microscopy (SEM) analysis demonstrated AgNP associated with CaGP. Ag+ ions were considerably higher in AgCaGP/C. C. albicans was susceptible to nanocompounds produced with both reducing agents, regardless of Ag concentration and CaGP form, being Ag10%CaGP-N/C the most effective compound (19.5–39.0 µg Ag mL−1). While for S. mutans, the effectiveness was observed only for AgCaGP reduced by citrate, also presenting Ag10%CaGP-N the highest effectiveness (156.2–312.5 µg Ag mL−1). Notably, CaGP enhanced the silver antimicrobial potential in about two- and eight-fold against C. albicans and S. mutans when compared with the AgNP controls (from 7.8 to 3.9 and from 250 to 31.2 µg Ag mL−1, respectively). The synthesis that was used in this study promoted the formation of AgNP associated with CaGP, and although the use of sodium borohydride (B) resulted in a pronounced reduction of Ag+, the composite AgCaGP/B was less effective against the microorganisms that were tested.

Antimicrobial Activity of Compounds Containing Silver Nanoparticles and Calcium Glycerophosphate in Combination with Tyrosol

“…The reaction occurred under constant agitation at 95°C for 10 min. For both routes, the amount of silver was equivalent to 10% of the CaGP weight [12,13].…”

“…These nanocompounds were previously characterized using the UV-visible spectrum, X-ray diffraction, and scanning electron microscopy followed by energy-dispersive X-ray spectroscopy with mapping in 2D, as described by Fernandes et al [12] and Souza et al [13].…”

“…Calcium glycerophosphate (CaGP) is an organic polyphosphate capable of adsorption to enamel surfaces [11], leading to the release of calcium (Ca) ions, which act on the remineralization process. Nanocomposites containing AgNPs and CaGP have been developed and demonstrated antimicrobial and remineralizing effects, attributed to the AgNPs and CaGP, respectively [12,13]. However, there is concern regarding the use of AgNPs, since a concentration-dependent toxicity has been documented [14].…”

Application of Antimicrobial Nanoparticles in Dentistry

“…The oral cavity constantly encounters a plethora of microorganisms [1]. Plaque biofilm—a major cause of caries, periodontitis and other dental diseases—is a complex community of bacteria or fungi that causes infection by protecting pathogenic microorganisms from external drug agents and escaping the host defense mechanisms [2]. Although significant numbers of study that focus on developing antimicrobial agents to overcome this problem exist, most of these attempts failed to achieve desired outcomes due to the rapid degradation and fast release of antibacterial agents causing low efficiency and safety concerns [3,4].…”

“…Smaller NPs could release their corresponding ions more to obtain a better antibacterial effect. Many kinds of research focused on the antibacterial properties of NPs and showed that NPs possessed superior antibacterial activity in bacteria of drug resistance [1,2,4]. Thus, the application of nanoparticles in dentistry might be particularly advantageous.…”