Citric Acid Cross-Linked Gelatin-Based Composites with Improved Microhardness

The aim of this study is to investigate the influence of cross-linking and reinforcements in gelatin on the physico-mechanical properties of obtained composites. The gelatin-based composites cross-linked with citric acid (CA) were prepared: gelatin type B (GB) and β-tricalcium phosphate (β-TCP) and novel hybrid composite GB with β-TCP and hydroxyapatite (HAp) particles, and their structure, thermal, and mechanical properties were compared with pure gelatin B samples. FTIR analysis revealed that no chemical interaction between the reinforcements and gelatin matrix was established during the processing of hybrid composites by the solution casting method, proving the particles had no influence on GB cross-linking. The morphological investigation of hybrid composites revealed that cross-linking with CA improved the dispersion of particles, which further led to an increase in mechanical performance. The microindentation test showed that the hardness value was increased by up to 449%, which shows the high potential of β-TCP and HAp particle reinforcement combined with CA as a cross-linking agent. Furthermore, the reduced modulus of elasticity was increased by up to 288%. Results of the MTT assay on L929 cells have revealed that the hybrid composite GB-TCP-HA-CA was not cytotoxic. These results showed that GB cross-linked with CA and reinforced with different calcium phosphates presents a valuable novel material with potential applications in dentistry.

The synthesis of Tween80/calcium phosphate nanocomposite bioactive gelatine-based gels as a proof of concept for tooth sensitivity home-treatment

Dentine hypersensitivity interferes with the lifestyle owing to pain arising from exposed dentine surfaces in response to stimuli. One common way to treat this problem is to occlude the exposed tubules. In this work, we have proposed a home-based treatment gel for tooth sensitivity. The gel was prepared using the emulsion method and contained Tween80/calcium phosphate nanocomposite that could occlude the tubules after 10 h of application. In preparation, Tween80 was used as a surfactant, and oleic acid was used as an oil phase to form a water-in-oil nanoreactor for calcium phosphate synthesis. Finally, different concentrations of gelatine were used to transform the emulsion into a stable gel. The nanoparticles had a uniform spherical shape and a diameter of approximately 300 nm. The nanocomposite gel containing the lowest amount of gelatine (Gel-T80-5%GE) exhibited the best liquid-like property and the highest occlusion rate of 95%.