Biomimetic Strontium Substituted Calcium Phosphate Coating for Bone Regeneration

Cellulose acetate (CA)/strontium phosphate (SrP) hybrid coating has been proposed as an effective strategy to build up novel bone-like structures for bone healing since CA is soluble in most organic solvents. Strontium (Sr2+) has been reported as a potential agent to treat degenerative bone diseases due to its osteopromotive and antibacterial effects. Herein, bioactive hybrid composite SrP-based coatings (CASrP) were successfully produced for the first time. CASrP was synthesized via a modified biomimetic method (for 7—CA7dSrP, and 14 days—CA14dSrP), in which the metal ion Sr2+ was used in place of Ca2+ in the simulated body fluid. Energy-dispersive X-ray (EDX) and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the SrP incorporation chemically in the CASrP samples. Atomic absorption spectroscopy (AAS) supported EDX data, showing Sr2+ adsorption into CA, and its significant increase with the augmentation of time of treatment (ca. 92%—CA7dSrP and 96%—CA14dSrP). An increment in coating porosity and the formation of SrP crystals were evidenced by scanning electron microscopy (SEM) images. X-ray diffraction (XRD) evidenced a greater crystallinity than CA membranes and a destabilization of CA14dSrP structure compared to CA7dSrP. The composites were extremely biocompatible for fibroblast and osteoblast cells. Cell viability (%) was higher either for CA7dSrP (48 h: ca. 92% and 115%) and CA14dSrP (48 h: ca. 88% and 107%) compared to CA (48 h: ca. 70% and 51%) due to SrP formation and Sr2+ presence in its optimal dose in the culture media (4.6–9 mg·L−1). In conclusion, the findings elucidated here evidence the remarkable potential of CA7dSrP and CA14dSrP as bioactive coatings on the development of implant devices for inducing bone regeneration.

Precise morphology control of phosphate-based nanospheres via magnesium and application in drug delivery

The present work investigates a template-free and rapid synthesis of phosphate-based porous nanospheres via magnesium. The study reveals the magnesium plays a guide role in the formation of amorphous porous magnesium substituted nanospheres, including calcium phosphate (CaP), strontium phosphate (SrP) and barium phosphate (BaP). Cell viabilities of three kinds of particles were evaluated and CaP nanospheres indicated best biocompatibility. Thus, amorphous magnesium substituted CaP nanospheres were chosen as doxorubicin (DOX) carrier for drug delivery in cancer treatment and pH-responsive magnesium substitution can switch on under tumour acidic microenvironment and facilitate controlled sustained DOX release. The CaP nanospheres gave a sustainable release within 150 minutes. The results showed free DOX has better efficiency at killing cancer cells than CaP/DOX at 4 h. However, CaP/DOX systems effectively suppressed the cell proliferation comparing with free DOX at 36 h. Collectively, this simple and templet-free method for synthesis of amorphous porous nanospheres could serve as a promising chemo-therapeutics delivery system and effectively inhibition of cancer cell growth.

Sustainable one-pot synthesis of strontium phosphate nanoparticles with effective charge carriers for photocatalytic degradation of carcinogenic naphthylamine derivative

Sustainable one-pot precipitation method was applied for synthesizing strontium phosphate nanoparticles (SrPO NPs) and utilized as effective charge separation photocatalyst for degradation of oncogenic napthylamine derivative (Congo red). Significant photocatalytic...