Prospects and challenges for the application of tissue engineering technologies in the treatment of bone infections

Osteomyelitis is a devastating disease caused by microbial infection in deep bone tissue.Its high recurrence rate and impaired restoration of bone deficiencies are major challenges in treatment.Microbes have evolved numerous mechanisms to effectively evade host intrinsic and adaptive immune attacks to persistently localize in the host,such as drug-resistant bacteria,biofilms,persister cells,intracellular bacteria,and small colony variants(SCVs).Moreover,microbial-mediated dysregulation of the bone immune microenvironment impedes the bone regeneration process,leading to impaired bone defect repair.Despite advances in surgical strategies and drug applications for the treatment of bone infections within the last decade,challenges remain in clinical management.The development and application of tissue engineering materials have provided new strategies for the treatment of bone infections,but a comprehensive review of their research progress is lacking.This review discusses the critical pathogenic mechanisms of microbes in the skeletal system and their immunomodulatory effects on bone regeneration,and highlights the prospects and challenges for the application of tissue engineering technologies in the treatment of bone infections.It will inform the development and translation of antimicrobial and bone repair tissue engineering materials for the management of bone infections.

Novel 3D printed shape-memory PLLA-TMC/GA-TMC scaffolds for bone tissue engineering with the improved mechanical properties and degradability

The biodegradable substitution materials for bone tissue engineering have been a research hotspot.As is known to all,the biodegradability,biocompatibility,mechanical properties and plasticity of the substitution materials are the important indicators for the application of implantation materials.In this article,we reported a novel binary substitution material by blending the poly(lactic-acid)-co-(trimethylenecarbonate)and poly(glycolic-acid)-co-(trimethylene-carbonate),which are both biodegradable polymers with the same segment of flexible trimethylene-carbonate in order to accelerate the degradation rate of poly(lactic-acid)-co-(trimethylene carbonate)substrate and improve its mechanical properties.Besides,we further fabricate the porous poly(lactic-acid)-co-(trimethylene-carbonate)/poly(glycolic-acid)-co-(trimethylene-carbonate)scaffolds with uniform microstructure by the 3D extrusion printing technology in a mild printing condition.The physicochemical properties of the poly(lactic-acid)-co-(trimethylenecarbonate)/poly(glycolic-acid)-co-(trimethylene-carbonate)and the 3D printing scaffolds were investigated by universal tensile dynamometer,fourier transform infrared reflection(FTIR),scanning electron microscope(SEM)and differential scanning calorimeter(DSC).Meanwhile,the degradability of the PLLATMC/GA-TMC was performed in vitro degradation assays.Compared with PLLA-TMC group,PLLA-TMC/GATMC groups maintained the decreasing Tg,higher degradation rate and initial mechanical performance.Furthermore,the PLLA-TMC/GA-TMC 3D printing scaffolds provided shape-memory ability at 37℃.In summary,the PLLA-TMC/GA-TMC can be regarded as an alternative substitution material for bone tissue engineering.