Self-Adaptive Antibacterial Scaffold with Programmed Delivery of Osteogenic Peptide and Lysozyme for Infected Bone Defect Treatment

Chitosan and hyaluronic acid based injectable dual network hydrogels - Mediating antimicrobial and inflammatory modulation to promote healing of infected bone defects

In bone defects, infections lead to excessive inflammation, increased bacterial, and bone lysis, resulting in irregular wounds that hinder new bone regeneration. Injectable bioactive materials with adequate antimicrobial activity and strong osteogenic potential are urgently required to remedy irregular defects, eradicate bacteria, and facilitate the generation of new bone tissue. In this research, injectable dual-network composite hydrogels consisting of sulfated chitosan, oxidized hyaluronic acid, β-sodium glycerophosphate, and CuSr doped mesoporous bioactive glass loaded with bone morphogenetic protein (CuSrMBGBMP-2) were utilized for the first time to treat infectious bone defects. Initially, the hydrogel was injected into the wound at 37 °C with minimal invasion to establish a stable state and prevent hydrogel loss. Subsequently, sulfated chitosan eliminated bacteria at the wound site and facilitated cell proliferation with oxidized hyaluronic acid. Additionally, CuSrMBGBMP-2 strengthened antibacterial properties, regulated inflammatory reactions, promoted angiogenesis and osteogenic differentiation, addressing the deficiency in late-stage osteogenesis. Specifically, the injectable dual-network hydrogel based on chitosan and hyaluronic acid is minimally invasive, offering antibacterial, anti-inflammatory, pro-angiogenic, and bone regeneration properties. Therefore, this hydrogel with injectable dual network properties holds great promise for the treatment of bone infections in the future.

Advances in 3D Printing of Highly Bioadaptive Bone Tissue Engineering Scaffolds

The number of patients with bone defects caused by trauma, bone tumors, and osteoporosis has increased considerably. The repair of irregular, recurring, and large bone defects poses a great challenge to clinicians. Bone tissue engineering is emerging as an appropriate strategy to replace autologous bone grafting in the repair of critically sized bone defects. However, the suitability of bone tissue engineering scaffolds in terms of structure, mechanics, degradation, and the microenvironment is inadequate. Three-dimensional (3D) printing is an advanced additive-manufacturing technology widely used for bone repair. 3D printing constructs personalized structurally adapted scaffolds based on 3D models reconstructed from CT images. The contradiction between the mechanics and degradation is resolved by altering the stacking structure. The local microenvironment of the implant is improved by designing an internal pore structure and a spatiotemporal factor release system. Therefore, there has been a boom in the 3D printing of personalized bone repair scaffolds. In this review, successful research on the preparation of highly bioadaptive bone tissue engineering scaffolds using 3D printing is presented. The mechanisms of structural, mechanical, degradation, and microenvironmental adaptations of bone prostheses and their interactions were elucidated to provide a feasible strategy for constructing highly bioadaptive bone tissue engineering scaffolds.

One-Step Purification Strategy for Cowpea Chlorotic Mottle Virus-Like Particles Produced by the IC-BEVS

Virus-like particles (VLP) of the cowpea chlorotic mottle virus (CCMV), a plant virus, have been shown to be safe and noncytotoxic vehicles for delivering various cargos, including nucleic acids and peptides, and as scaffolds for presenting epitopes. Thus, CCMV-VLP have acquired increasing attention to be used in fields such as gene therapy, drug delivery, and vaccine development. Regardless of their production method, most reports purify CCMV-VLP through a series of ultracentrifugation steps using sucrose density gradient ultracentrifugation, which is a complex and time-consuming process. Here, the use of anion exchange chromatography is described as a one-step protocol for purification of CCMV-VLP produced by the insect cell-baculovirus expression vector system (IC-BEVS).

UiO66-based molecularly imprinted polymers with water-compatible deep eutectic solvent as functional monomer for purification of lysozyme from egg white

Protein-templated molecularly imprinted polymers have limitations such as poor mass transfer, slow recognition kinetics, and difficulties in isolation and purification due to their large molecular sizes, complex structures, and flexible conformations. To address these limitations and obtain lysozyme (Lyz)-imprinted polymers, a molecularly imprinted polymer (UiO66@DES-MIPs) was prepared for the first time by using Lyz as a template molecule, a metal-organic framework (UiO66-NH2) as a matrix, and a water-compatible deep eutectic solvent (DES) as a functional monomer. The introduction of UiO66-NH2 by the solvothermal method with a large specific surface area and favorable stability and resistance to environmental disturbances into the MIPs can reduce the "embedding" phenomenon and acquire a higher binding capacity and fast mass transfer. In addition, a water-soluble binary DES (1:2 molar ratio of choline chloride to 1,3 dimethylurea) prepared by a hydrothermal method as a functional monomer generates multiple forces with Lyz, increasing the hydrophilicity of UiO66@DES-MIPs and contributing to the formation and stabilization of the imprinted sites. Consequently, UiO66@DES-MIPs exhibited good selectivity, water compatibility, and fast adsorption equilibrium (the adsorption equilibrated at 243.87 ± 4.88 mg g-1 in 90 min). Besides, reusability experiments indicated that the UiO66@DES-MIPs could be recycled six times without obvious loss of adsorption capacity. The imprinting factor of UiO66@DES-MIPs is 3.67. The isolation and purification of Lyz from egg white confirmed the practicability of UiO66@DES-MIPs. The high adsorption capacity and specific recognition make this polymer a promising candidate for the isolation and purification of biological macromolecules.