ZnL₂-BPs Integrated Bone Scaffold under Sequential Photothermal Mediation: A Win–Win Strategy Delivering Antibacterial Therapy and Fostering Osteogenesis Thereafter

Abstract

Implant-related infections are serious complications after bone surgery and can compromise the intended functions of artificial implants, leading to surgical failure and even amputation in severe cases. Various strategies have been proposed to endow bone implants with the desirable antibacterial properties, but unfortunately, most of them inevitably suffer from some side effects detrimental to normal tissues. In this study, a multifunctional bone implant is designed to work in conjunction with sequential photothermal mediation, which can deliver antibacterial therapy (<50 °C) in the early stage and foster bone regeneration (40–42 °C) subsequently. Black phosphorus nanosheets (BPs) are coordinated with zinc sulfonate ligand (ZnL2), and the ZnL2-BPs are integrated into the surface of a hydroxylapatite (HA) scaffold to produce ZnL2-BPs@HAP. In this design, BPs produce the photothermal effects and ZnL2 increases the thermal sensitivity of peri-implant bacteria by inducing envelope stress. The biosafety of the antibacterial photothermal treatment is improved due to the mild temperature, and furthermore, gradual release of Zn2+ and PO4 3– from the scaffold facilitates osteogenesis in the subsequent stage of bone healing. This strategy not only broadens the biomedical applications of photothermal treatment but also provides insights into the design of multifunctional biomaterials in other fields.

Nanomaterial-Based Zinc Ion Interference Therapy to Combat Bacterial Infections

“…They could not only exert an excellent antibacterial function but also act as nutrients or stimulus signals for damaged tissues. In wound and osteomyelitis mouse models, Zn(II) accelerates wound healing and improves osteogenic differentiation of bone marrow mesenchymal stem cells ( 42 ). Therefore, with the ever-developing MDR bacteria and the slow pace of development of efficient antibiotics, Zn(II) interference therapy might offer an alternative option to combat bacterial infection.…”

A Composite Deferoxamine/Black Phosphorus Nanosheet/Gelatin Hydrogel Scaffold for Ischemic Tibial Bone Repair

“… 46 Wu et al also reported that Black phosphorus nanosheets facilitates osteogenesis in the subsequent stage of bone healing. 47 Those results indicates that BPN-DFO hydrogel can promote the osteogenesis of hBMSC in Vitro.…”

Bioceramic-based scaffolds with antibacterial function for bone tissue engineering: A review

“…The photothermal effect can be applied for antibacterial purposes, but a single material's photothermal efficiency is often insufficient. Hence, a combination of two or more photothermal materials is expected to overcome the hurdles [ 31 , 121 ]. For example, the latest study reported a bone implant with antibacterial action by integrating ZnL 2 with thermosensitivity and BPs with photothermal property on HA scaffold ( Fig.…”

“…For example, the latest study reported a bone implant with antibacterial action by integrating ZnL 2 with thermosensitivity and BPs with photothermal property on HA scaffold ( Fig. 7 ) [ 121 ]. In detailed experiments, ZnL 2 -BPs were synthesized by ligating BPs with ZnL 2 and then integrating them onto the surface of 3D-printed HA scaffolds to form ZnL 2 -BPs@HA scaffolds ( Fig.…”

“…(c1) antibacterial efficiency of the scaffolds with/without NIR irradiation, (c2) quantitative analysis of live/dead staining (reprinted with permission from ref. [ 121 ]). …”