The antimicrobial activity of the GA-AgNPs against three bacterial strains: S. sanguinis (NCTC 7865), S. mutans (NCTC 10449), L. acidophilus (ATCC 314), and one fungal strain C. albicans (ATCC 10231) was determined using the agar disc diffusion and the microdilution assays. The S. sanguinis and S. mutans were purchased from Davies Diagnostics (Randburg, Johannesburg, South Africa); and L. acidophilus and C. albicans were purchased from the American Type Culture Collection (ATCC; Manassas, Virginia, USA).
All the microbes were cultured on Brain Heart Infusion (BHI) Broth (Sigma–Aldrich), and single colonies were subcultured in BHI agar (Sigma–Aldrich) for all the bacterial strains and Sabouraud dextrose agar for C. albicans at 37°C for 24 hours. Following the overnight incubation, the microbes were adjusted to the 0.5 McFarland standard (Mcf) using DensiCHEK Plus standards (BioMérieux, Inc., Durham, NC, USA).
All the microbes were cultured on Brain Heart Infusion (BHI) Broth (Sigma–Aldrich), and single colonies were subcultured in BHI agar (Sigma–Aldrich) for all the bacterial strains and Sabouraud dextrose agar for C. albicans at 37°C for 24 hours. Following the overnight incubation, the microbes were adjusted to the 0.5 McFarland standard (Mcf) using DensiCHEK Plus standards (BioMérieux, Inc., Durham, NC, USA).