Laboratory performance of novel injectable keratin nanoparticle from poultry feathers loaded-alginate composite hydrogel as a pulpotomy filling biomaterial for dentin regeneration.

Background: Various medicaments have been utilized as an aid for wound healing following vital pulp treatment. Many of them are synthetic in origin and have disadvantages as limited amount of cytotoxicity and great expense. Hence, to tackle these drawbacks, naturally derived blended scaffolds have been employed in renovative dental field. Current research attempts to synthesize and characterize physicochemical performance of the newly injectable alginate hydrogel loaded with chicken feather regenerated keratin nanoparticles (nKer NPs) in different percentages as a new pulpotomy agent.

Methods: Alginate hydrogels were developed by dissipating alginate powder in alcohol distilled water including nKer NPs at 0.5, 1.0 and 1.5 wt%. The obtained mix was agitated and sustained at nighttime in water-bath at 50C to assure adequate solvability. A sterilized dual syringe assembly was utilized to blend alginate phase with 20 wt% calcium chloride phases, producing hydrogel during ejection. Next, all fabricated hydrogel specimens were characterized by FTIR, SEM, thermal and mechanical stability, viscosity, surface wettability and cell viability. Statistical analysis was conducted utilizing One-Way ANOVA comparing between groups. Multiple pairwise comparisons applying Bonferroni adjusted significance level (p ≤ 0.05) were performed.

Results: Alginate/nKer NPs (1.0 wt%) loaded group (IIb) exhibited wide (243 μm), open pores with adequate interconnectivity. Thermal stability (T 185.8-285.77C) (T 185.8-488.23C) (T 488.23-600C) was improved in all loaded hydrogels relative to control group (T 65C) (T 65-30 C) (T 350-635). Further increase in nKer NPs content elevated thermal stability [T: IIa 185.8, IIb 191.85, IIc 285.77C]. Greatest Compressive Young's Modulus and collapse/yield stress were displayed in group IIb [2.28, 1.14 (MPa)]; respectively (p ≤ 0.05). Moreover, group IIb exhibited the best hydrophilic behavior (θ 32.03) (p ≤ 0.05). The increase in concentration of nKer NPs within the hydrogel increased the hydrogel viscosity. MTT assay disclosed that cell viability percentage of gingival fibroblasts decreased by elevating the content of powder and hydrogel extracts following 24 and 48 h, yet greater than approved cytotoxicity % (˃70%).

Conclusion: The favorable experimental behavior of the injectable alginate/nKer NPs (1.0 wt%) hydrogel advocated it as encouraging applicant for pulpotomy promoting the regeneration of dentin in clinical implementations.