Sterilizing bioinks: Understanding the impact of techniques on 3D bioprinting materials

Natural polymers, such as alginate, chitosan, gelatin, and their derivatives, are widely used in formulating bioinks for 3D bioprinting of tissue engineering scaffolds. Due to their natural origin and biodegradable nature, these polymers are highly susceptible to microbial contamination, making effective sterilization crucial. This research paper provides a comprehensive analysis of the effects of various sterilization methods, namely, ultraviolet radiation, autoclaving, ethylene oxide treatment, membrane filtration, and lyophilization, on the physical and chemical properties, bioprinting performance, mechanical strength, and biocompatibility of these polymers. Additionally, experiments have been conducted to assess the impact of sterilization on commonly used viscosity enhancers, such as pectin, xanthan gum, and guar gum, bioactive nanofillers like montmorillonite and hydroxyapatite, and crosslinking agents like calcium chloride, citric acid, glutaraldehyde, and Irgacure 2959, which are other critical components in bioink formulations. The findings highlight that the choice of sterilization method should be tailored to the specific component, considering their physicochemical properties, applications, and practical convenience. This study involves a comprehensive examination of different sterilization techniques for several bioink components, highlighting the importance of selecting an appropriate method to ensure bioink stability. Unlike previous research, it offers a more extensive evaluation by covering a wide range of commonly used bioink constituents and examining the impact of diverse sterilization methods on their stability, thereby offering new insights into optimizing sterilization protocols for enhanced and reproducible bioprinting outcomes.