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

**Gabriela Lopes Fernandes 1, Alberto Carlos Botazzo Delbem 2, Jackeline Gallo do Amaral 2, Luiz Fernando Gorup 3,4, Renan Aparecido Fernandes 1,5, Francisco Nunes de Souza Neto 3, José Antonio Santos Souza 2, Douglas Roberto Monteiro 6, Alessandra Marçal Agostinho Hunt 7, Emerson Rodrigues Camargo 3 and Debora Barros Barbosa 1,\***


Received: 27 April 2018; Accepted: 25 June 2018; Published: 27 June 2018

**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 agen<sup>t</sup> 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.

**Keywords:** silver; calcium glycerophosphate; nanoparticles; *Candida albicans*; *Streptococcus mutans*
