Electrosprayed Chitosan–Calcium Phosphate Microshell Composite Coatings on Silanized Titanium Substrates

Chitosan and calcium phosphate (CaP) are attractive bioactive coating materials for titanium (Ti) orthopedic implants, but coating approaches must provide uniform deposition, adequate adhesion, and cytocompatibility. This proof-of-concept study evaluated whether CaP microshells could be incorporated into electrosprayed chitosan coatings bonded to silanized Ti substrates without compromising coating properties. CaP microshells were synthesized using carbon microsphere templates and added to chitosan electrospray solutions at 0.25, 0.5, and 1.0 wt% relative to chitosan. Electrospray parameters were adjusted, and coatings were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, tensile adhesion testing, water contact angle measurements, and W-20-17 bone marrow stromal cell culture. Increasing capillary diameter and reducing pressure enabled stable deposition of uniform composite coatings containing up to 1.0 wt% CaP. CaP microshells were distributed across the coating surfaces and throughout the coating thickness. Silanization significantly increased coating adhesion compared with non-silanized Ti, while CaP incorporation up to 1.0 wt% did not significantly reduce bond strength. All coatings were hydrophilic and supported viable cell attachment and growth over five days. These findings support the feasibility of electrosprayed chitosan–CaP microshell coatings as adhesive, cytocompatible bioactive coating platforms for Ti implant materials.