Antibacterial activity of modified hydroxyapatite (HAp) from lacustrine mussels (Anodonta nutaliana) shells obtained from Poso lake

Hydroxyapatite (HAp) was a type of bioceramics synthesized from Calcium. In this study, HAP synthesized from the shell of A. nutaliana is applied as an active ingredient in a toothpaste formula to treat and remineralize the tooth enamel layer. The antibacterial activity of HAp against 4 species of caries bacteria; Nocardia asteroides, Nocardia erythropolys; Lactobacillus acidophilus; and Streptococcus mutans showed the inhibitory area sequentially 0.00 ± 0.000mm; 0.00 ± 0.0000mm; 5.21 ± 0.0273mm; and 0.00 ± 0.0000mm; those inhibitory area belongs to the very weak antibacterial range. To increase the antibacterial activity, the HAp was modified using Chitosan, CNt, and a mix of Chitosan and CNt. The modification using Chitosan increases the antibacterial activity against the same bacteria. The inhibitory area showed sequentially 22.08 ± 0.0186 mm; 22.26 ± 0.0186 mm; 22.36 ± 0.0088 mm; and 21.19 ± 0.0120 mm, classified into very strong antibacterial range. The modification using CNt increases the antibacterial activity against same bacteria, the inhibitory area showed sequentially 10.34 ± 0.0033mm; 7.04 ± 0.0145mm; 11.07 ± 0.0265mm; and 8.45 ± 0.0145mm, then classified into weak-middle antibacterial range. The modification by the mix of Chitosan:CNt showed the increase of antibacterial activity against the same bacteria, the inhibitory area showed sequentially 18.10 ± 0.0153mm; 18.03 ± 0.0058mm; 19.05 ± 0.0058 mm; and 17.17 ± 0.0289mm, categorized as a middle antibacterial range. The modification also stabilized using the mineral ions; Ag, Ti, Zn, and Mg causing an increase in antibacterial activity. The overall results of modifications to the HAp succeed to increase the antibacterial activity of the HAp against the caries bacteria.