Immunomodulatory biomaterials for implant-associated infections: from conventional to advanced therapeutic strategies

Abstract

Implant-associated infection (IAI) is increasingly emerging as a serious threat with the massive application of biomaterials. Bacteria attached to the surface of implants are often difficult to remove and exhibit high resistance to bactericides. In the quest for novel antimicrobial strategies, conventional antimicrobial materials often fail to exert their function because they tend to focus on direct bactericidal activity while neglecting the modulation of immune systems. The inflammatory response induced by host immune cells was thought to be a detrimental force impeding wound healing. However, the immune system has recently received increasing attention as a vital player in the host’s defense against infection. Anti-infective strategies based on the modulation of host immune defenses are emerging as a field of interest. This review explains the importance of the immune system in combating infections and describes current advanced immune-enhanced anti-infection strategies. First, the characteristics of traditional/conventional implant biomaterials and the reasons for the difficulty of bacterial clearance in IAI were reviewed. Second, the importance of immune cells in the battle against bacteria is elucidated. Then, we discuss how to design biomaterials that activate the defense function of immune cells to enhance the antimicrobial potential. Based on the key premise of restoring proper host-protective immunity, varying advanced immune-enhanced antimicrobial strategies were discussed. Finally, current issues and perspectives in this field were offered. This review will provide scientific guidance to enhance the development of advanced anti-infective biomaterials.

A Review on Nano Ti-Based Oxides for Dark and Photocatalysis: From Photoinduced Processes to Bioimplant Applications

“…This so-called race for the surface [ 34 , 35 , 36 , 37 ] determines whether the implant will succeed or fail, especially after surgery and during wound healing [ 34 ]. This depends on whether the host cells can attach to the implant irreversibly before bacterial cells do so in the irreversible phase of biofilm formation ( Figure 8 b) [ 38 ]. To further improve the interface between bone and the implant, biocompatible oxides, such as TiO 2 , are used to facilitate this bridging.…”

“…Titanium, from which TiO 2 can be grown, exhibits excellent mechanical properties which helped in establishing its place in the field of biomedical implants. For example, titanium and its alloys are standard materials used for bone implants, and strong research in medicine and engineering is focused on continuously improving their physicochemical properties, mechanical properties, and designability/processability [ 29 , 30 , 31 , 32 , 33 ], on top of added functionalities desired in modern biomaterials, such as its antimicrobial and regenerative properties [ 34 , 35 , 36 , 37 , 38 , 39 ]. The last two are also attributed to its catalytic ROS-forming ability, which should then be considered in bioimplant applications.…”

Neutrophil-inspired photothermo-responsive drug delivery system for targeted treatment of bacterial infection and endotoxins neutralization

“…Various biomaterials have taken advantages of inflammation-targeting functions of neutrophils to treat inflammation-related diseases such as rheumatoid arthritis, ischemia brain damage and cancers [ 23 , 29 , 30 , 52 ]. However, the neutrophil-based biomaterials or drug delivery systems for treatment of infectious diseases have been rarely reported [ 53 ]. Although a very recent report showed that neutrophil membrane vesicles (NMVs) are able to encapsulate the antibiotic ceftazidime, the inflammation-targeting functions in vivo was not studied and antibacterial efficacy of ceftazidime-loaded NMVs was very limited (< 50% bacterial reduction in a bacterium-induced peritonitis model) [ 54 ].…”

Biodegradable Implants for Internal Fixation of Fractures and Accelerated Bone Regeneration

“…Internal fixation has an advantage in realizing functional reduction and anatomical reduction simultaneously, whereas it also tends to result in more severe and increased risk of complications, such as damage to muscle and nerve, chronic pain, nonunion or mal-union of bones, and arthritis or tendinitis. In particular, implant-associated infections, one of the most severe complications of orthopedic internal fixation surgeries, has happened even more frequently, resulting in prolonged pain of patients. , …”