Design and characterization of ftaxilide-conjugated vinylphosphonic acid-modified hydroxyapatite nanohybrids for anti-mycobacterial applications

Abstract This current study designed, synthesized and evaluated a novel inorganic–organic nano-conjugate (NC) system based on vinylphosphonic acid-modified hydroxyapatite (VPA-HA) and the natural compound ftaxilide to observe the anti-mycobacterial activity. HA nanoparticles were synthesized and subsequently functionalized with VPA to obtain VPA-HA. The NC was fabricated through coordination-assisted conjugation involving Fe³+/Fe²+ redox mediation. The physicochemical characterization was performed using UV–visible spectroscopy, Fourier transform infrared spectroscopy, particle size analysis, zeta potential measurements, scanning electron microscopy and X-ray diffraction (XRD). Spectroscopic analyses confirmed successful conjugation and the appearance of new functional group interactions. Morphological studies revealed nanoscale particles with sizes of approximately 80 nm (VPA-HA) and approximately 200 nm (NC). XRD patterns confirmed the crystalline hexagonal HA structure with slight modifications after functionalization. Computational investigations, including density functional theory, frontier molecular orbital and molecular electrostatic potential analyses, demonstrated enhanced stability and favourable electronic properties of the NC. The interactions against the Mycobacterium tuberculosis target protein (PDB ID: 1GTV) revealed good binding affinity of the NC (−109.29 kcal mol−1). Biological evaluation demonstrated potential anti-mycobacterial activity of the NC with a minimum inhibitory concentration of 2 µg ml−1. The synthesized NC exhibits enhanced therapeutic efficacy, stability and promising potential as an anti-tubercular drug delivery system.