Antibacterial dual cross-linked hydrogels for Periodontal Regeneration

Abstract

Periodontitis is one of the most common gum diseases caused by bacterial infection. It affects teeth's surrounding bone and tissues. It is important to treat the disease promptly as it not only results in tooth loss but also affects the general health of the patient. It is extremely common in young individuals with occurrence rates of approximately 50% across the world. Different graft materials are used to treat periodontal defects, but unpredictable clinical outcomes of existing solutions encourage developing novel materials with enhanced functionality. This study aimed to formulate oval proteins, hydroxyapatite (HA) and PVA based anti-bacterial dual cross-linked hydrogels for periodontal regeneration. Potential non toxic and biodegradable oxidized alginate, borax and divalent ionic (Cu+2, Zn+2, Ca+2) solutions were used as cross linking agents. Oval proteins act as efficient gelling agent and can mimic the ECM microenvironment. Hydrophilicity, potential bio degradation, outstanding cytocompatibility, less cytotoxicity, surface alignment features, and self-healing are some of distinctive properties of prepared hydrogels. Hydroxyapatite (HA) is a bio-ceramic and used as bone regeneration material. In the first step HA was synthesized by economical wet chemical method and alginate was oxidized by using NaIO4. Oxidation of alginate was optimized to get optimum number of aldehyde groups for crosslinking. In next step hydrogel synthesis was optimized by changing relative ratio of polymers, HA and cross linker. Finally, four different hydrogels were prepared by using optimized ratio to evaluate the effect of ix metallic cross linkers on hydrogel strength, biological and antibacterial properties. Prepared hydrogels samples were named as Alg, Ca-Alg, Cu-Alg, and Zn-Alg hydrogels, where Alg was hydrogel without metallic cross linker and Ca-Alg, Cu-Alg, and Zn-Alg were containing calcium, copper and zinc ions respectively as a cross linker. Prepared samples were characterized by Fourier transform infrared spectroscopy (FTIR) and X-rays diffraction. FT-IR analysis showed the successful synthesis of HA, oxidation of alginate and development of covalent and non-covalent linkages among different components of prepared hydrogels. XRD analysis confirmed the formation of phase pure HA. Synthesized hydrogels showed the good swelling property in PBS solution (58-328 times). Biodegradation analysis indicated maximum 45% degradation of Ca-Alg hydrogel in 28 days. Prepared hydrogels showed effective antibacterial activity against both strains Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Cu-Alg hydrogel showed 33.8mm and 30.8mm zone of inhibition against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) respectively. The contact angel values supported the crosslinking among the different components of hydrogels. The prepared hydrogels were hydrophilic in nature. Prepared hydrogels showed non-toxic behavior when proliferated with NIH3T3 cell lines. Physical and biological properties of prepared hydrogels indicated that they can be used as a potential candidate to manage periodontal defects.