Antibacterial calcium phosphate composite cements reinforced with silver-doped magnesium phosphate (newberyite) micro-platelets.

This article demonstrates our efforts in developing and evaluating all-ceramic, biodegradable composites of calcium phosphate cements (CPCs) reinforced with silver (Ag)-doped magnesium phosphate (MgP) crystals. Two primary goals of this study were to 1) enhance CPC's poor mechanical properties with micro-platelet reinforcement, and 2) impart antibacterial functionalities in composites with the aim to inhibit surgical site infections (SSI). The work embodies three novel features. First, as opposed to well-known reinforcements with whisker or fiber-like morphology, we explored micro-platelets for the first time as the strengthening phase in the CPC matrix. Second, in contrast to conventional polymeric or calcium phosphate (CaP) fibrous reinforcements, newberyite (NB, MgHPO4.3H2O) micro-platelets belonging to the less explored yet promising MgP family, were evaluated as reinforcements for the first time. Third, NB micro-platelets were doped with Ag+ ions (AgNB, Ag content: 2 wt%) for enhancing antibacterial functionalities. Results indicated that 1 wt% of AgNB micro-platelet incorporation in the CPC matrix enhanced the compressive and flexural strengths by 200% and 140% respectively as compared to the un-reinforced ones. Besides, antibacterial assays revealed effective bactericidal functionalities (>99% bacteria kill) of the AgNB reinforced CPCs against Escherichia coli. Finally, cytocompatibility studies confirmed favorable pre-osteoblast cell proliferation and differentiation in vitro. Hence, this effort was successful in developing a self-setting and injectable AgNB reinforced CPC composition with favorable mechanical and antibacterial properties.

Magnetic Calcium Phosphate Cement for Hyperthermia Treatment of Bone Tumors.

This article reports, for the first time, the 'proof-of-concept' results on magnetic monetite (CaHPO4)-based calcium phosphate cements (CPCs) compositions developed for the hyperthermia treatment of bone tumors. Hyperthermia involves the heating of a tumor within a temperature range of 40-45 °C, inducing apoptosis in the tumor cells. This process holds promising potential in the field of cancer treatment and has been proven to be more effective than conventional therapeutics. Hence, we aimed to develop cement compositions that are capable of the hyperthermia treatment of bone tumors. To achieve that central goal, we incorporated iron oxide (Fe3O4), a ferromagnetic material, into monetite and hypothesized that, upon the application of a magnetic field, magnetite will generate heat and ablate the tumor cells near the implantation site. The results confirmed that an optimized content of magnetite incorporation in monetite can generate heat in the range of 40-45 °C upon the application of a magnetic field. Furthermore, the compositions were bioactive and cytocompatible with an osteoblastic cell line.