A promising therapeutic biomaterial: CHX@ZnO-HA/PSSS nanocomposites enable pH-Dependent infection eradication and bone regeneration in osteomyelitis.

OBJECTIVES

Osteomyelitis is a considerable clinical problem, necessitating multifunctional biomaterials that can concurrently manage infection and facilitate bone tissue regeneration. In this study, a chlorhexidine-loaded zinc oxide-hydroxyapatite/poly(sodium 4-styrene sulfonate) (CHX@ZnO-HA/PSSS) nanocomposite for possible therapeutic scaffold applications was manufactured and characterized.

METHODS

The nanocomposite was synthesized using a chemical precipitation process and studied using Fourier transform-infrared spectroscopy, X-ray diffraction, scanning electron microscopy-energy dispersive X-ray spectroscopy, and transmission electron microscopy to assess its chemical composition, crystallinity, and morphology. The in vitro bioactivity was assessed via immersion in simulated body fluid (SBF), and the drug release kinetics were predicted under physiological circumstances (pH 7.4). The biological performance was evaluated using MG-63 osteoblast-like cells, which were assessed via the MTT assay, dual acridine orange and ethidium bromide staining, scratch assays, and real-time polymerase chain reaction analysis of osteogenic markers (BMP2, RUNX2, osteocalcin, alkaline phosphatase, and type 1 collagen).

RESULTS

Characterization tests demonstrated the effective incorporation of the amorphous PSSS/CHX layer onto the crystalline ZnO-HA framework. Studies using SBF indicated the time-dependent bioactivity, characterized by the development of a dense, bone-like apatite layer by day 7. Drug release analysis indicated a biphasic, sustained pattern, achieving 40% cumulative release of CHX over 24 h at pH 7.4, regulated by Fickian transport kinetics. Biological assays demonstrated that the CHX@ZnO-HA/PSSS composite markedly improved cell survival (97%), accelerated wound closure in scratch tests, and upregulated essential osteogenic genes relative to the untreated progenitor control group.

CONCLUSION

The CHX@ZnO-HA/PSSS composite exhibited good cytocompatibility, low apoptotic induction, and high in vitro osteogenic potential. These findings show that the nanocomposite is a promising, multifunctional biomaterial for localized bone infection treatment and osseointegration enhancement.