Antioxidant Effects of Bioactive Glasses (BGs) and Their Significance in Tissue Engineering Strategies

Abstract

Elevated levels of oxidative stress are usually observed following injuries, leading to impaired tissue repair due to oxidation-related chronic inflammation. Several attempts have been made to manage this unfavorable situation, and the use of biomaterials with antioxidant activity is showing great promise in tissue engineering and regenerative medicine approaches. Bioactive glasses (BGs) are a versatile group of inorganic substances that exhibit an outstanding regenerative capacity for both hard and soft damaged tissues. The chemical composition of BGs provides a great opportunity for imparting specific biological activities to them. On this point, BGs may easily become antioxidant substances through simple physicochemical modifications. For example, particular antioxidant elements (mostly cerium (Ce)) can be added to the basic composition of the glasses. On the other hand, grafting natural antioxidant substances (e.g., polyphenols) on the BG surface is feasible for making antioxidant substitutes with promising results in vitro. Mesoporous BGs (MBGs) were demonstrated to have unique merits compared with melt-derived BGs since they make it possible to load antioxidants and deliver them to the desired locations. However, there are actually limited in vivo experimental studies on the capability of modified BGs for scavenging free radicals (e.g., reactive oxygen species (ROS)). Therefore, more research is required to determine the actual potential of BGs in decreasing oxidative stress and subsequently improving tissue repair and regeneration. The present work aims to highlight the potential of different types of BGs in modulating oxidative stress and subsequently improving tissue healing.

Keywords: bioactive glasses (BGs); free radicals; oxidative stress; tissue engineering; wound healing.

Figure 1

Reactive oxygen species (ROS) scavenging and surface regeneration properties of cerium oxide nanoparticles. Reproduced with permission from Ref. [83].

Figure 2

Schematic representation of the decisive role of the chemical composition of BGs, i.e., Hench (H-series) and Kokubo (K-series) glasses, on catalase mimetic activity capacity of cerium (Ce). Reproduced with permission from Ref. [84].

Figure 3

Schematic representation of Ce-doped nano-bioactive glasses based on 60SiO₂-(10-x)B₂O₃-25CaO-5P₂O₅-xCeO₂, in mole% (x = 0 and 5 mol%) as multifunctional bone fillings for drug delivery of ciprofloxacin. Reproduced with permission from Ref. [94].