Photosensitive and Conductive Hydrogel Induced Innerved Bone Regeneration for Infected Bone Defect Repair

Abstract

Repairing infected bone defects is a challenge in the field of orthopedics because of the limited self-healing capacity of bone tissue and the susceptibility of refractory materials to bacterial activity. Innervation is the initiating factor for bone regeneration and plays a key regulatory role in subsequent vascularization, ossification, and mineralization processes. Infection leads to necrosis of local nerve fibers, impeding the repair of infected bone defects. Herein, a biomaterial that can induce skeletal-associated neural network reconstruction and bone regeneration with high antibacterial activity is proposed for the treatment of infected bone defects. A photosensitive conductive hydrogel is prepared by incorporating magnesium-modified black phosphorus (BP@Mg) into gelatin methacrylate (GelMA). The near-infrared irradiation-based photothermal and photodynamic treatment of black phosphorus endows it with strong antibacterial activity, improving the inflammatory microenvironment and reducing bacteria-induced bone tissue damage. The conductive nanosheets and bioactive ions released from BP@Mg synergistically improve the migration and secretion of Schwann cells, promote neurite outgrowth, and facilitate innerved bone regeneration. In an infected skull defect model, the GelMA-BP@Mg hydrogel shows efficient antibacterial activity and promotes bone and CGRP + nerve fiber regeneration. The phototherapy conductive hydrogel provides a novel strategy based on skeletal-associated innervation for infected bone defect repair.

Recent advances in GelMA hydrogel transplantation for musculoskeletal disorders and related disease treatment

“…Innervation is an important initiator of bone regeneration and is involved in the process of bone growth and repair, so the importance of nerve regeneration needs to be taken into account when using tissue-engineered scaffolds to repair bone defects. In this way, Jing et al 58 used magnesium-modified black phosphorus (BP@Mg) incorporated into GelMA to prepare a photosensitive conductive hydrogel for infected bone defects and found that it not only had efficient antibacterial properties, but also promoted nerve and bone growth. Vascularised osteogenesis is essential for successful bone regeneration, so promoting vascular growth while treating bone defects is an important strategy.…”

Bioinspired Mild Photothermal Effect-Reinforced Multifunctional Fiber Scaffolds Promote Bone Regeneration

“…Postoperative infection is a key cause of bone repair failure in the clinical application of bone implants, which makes orthopedic surgeons face the challenge of formulating local antibiotic treatment strategies to prevent infection and promote bone healing. , As an emerging treatment modality, near-infrared (NIR) light-assisted hyperthermia has made amazing progress in tumor ablation and antibacterial therapy. , However, excessive temperature can cause damage to normal tissue at the lesion, so it is necessary to explore NIR light-triggered antibacterial synergistic therapy within a safe temperature range. Phase-change materials (PCM) are simple and effective controlled-release platforms due to their accurate response to temperature. , When the temperature reaches the melting point of the PCM to trigger the solid-to-liquid phase transition, the payloads can be released with the flow .…”

Nanomaterial-based biohybrid hydrogel in bioelectronics

“…In one study, the gelatin methacryloyl (GelMA) was combined with magnesium-modified black phosphorus nanosheets (BP@Mg) to fabricate a photosensitive conductive GelMA-BP@Mg (GBM) hydrogel for healing infected bone (Fig. 5 b) [ 90 ]. When exposed to NIR light, the GBM hydrogel displayed effective antibacterial effects and decreased the inflammation caused by infection because of the photothermal properties of the BP@Mg.…”

“…5 a Schematic diagram of a visible-light-mediated nano-biomineralization method for the synthesis of BTH through the photocatalytic activity of ruthenium. Reproduced with permission from [ 88 ], copyright American Chemical Society, 2022. b Schematic images of the fabrication process of GelMA-BP@Mg composed of GelMA and BP@Mg and exhibiting the photothermal properties of the GelMA-BP@Mg. Reproduced with permission from [ 90 ], copyright John Wiley and Sons, 2021. c Schematic images of the fabrication process of ECM-Au NP-based composite hydrogel and encapsulation of cardiac cells for heart disease (ischemia–reperfusion) treatment. Reproduced with permission from [ 94 ], copyright John Wiley and Sons, 2021 …”