Cissus quadrangularis mediated biogenic synthesis of silver-nanohydroxyapatite-mesoporous silica nanocomposite, characterization, and cytotoxicity evaluation on dental pulp stem cells

This study focuses on tripartite synthesis of Silver (AgNPs), Mesoporous Silica (MSNs), and Hydroxyapatite (n-HAp) nanoparticles with aqueous extract of Cissus quadrangularis (Veldt grape plant; Indian name: Pirandai) as a reducing agent. The dried and powdered form of the plant was subjected to aqueous extraction. The phytochemicals analysis was qualitatively estimated which detected the presence of alkaloid, tannin, phenol, terpenoid, steroid and saponin. The total phenol content of the extract was quantitatively estimated which resulted in Gallic acid equivalent (GAE) of 88.9 mg/g. This aqueous extract was then used in the synthesis of AgNPs, followed by synthesis of MSNs and n-HAp. These three nanoparticles were again combined together and re-synthesized in a tripartite manner to create a novel nanocomposite material. This nanocomposite was characterized by using techniques such as UV-vis spectroscopy, X-ray Diffraction (XRD) and Fourier-Transfer Infrared Spectroscopy (FTIR) to detect the presence, size, stability and functional groups of the synthesized nanoparticles. The bioavailability of synthesized nanoparticles was evaluated by testing their cytotoxicity against dental pulp stem cells (DPSC), which resulted in IC₅₀ values of 49.004, 106.869, 113.711, 131.27 µg/ml for AgNP, n-HAp, MS and tripartite composite respectively. Following this, the proliferation rate of DPSC cells treated culture media diluted composites in the ratio 1:1, 1:2 and 1:4 was evaluated. From the results it was found that cells co-cultured with composite dilution has shown increased proliferation rate. These findings highlight the biocompatibility and the potential of tripartite synthesized nanocomposite, when incorporated in dental restorative materials may give promising results.