Bone exhibits piezoelectric properties. Thus, electrical stimulations such as pulsed electromagnetic fields (PEMFs) and stimuli-responsive piezoelectric properties of scaffolds have been investigated separately to evaluate their efficacy in supporting osteogenesis. However, current understanding of cells responding under the combined influence of PEMF and piezoelectric properties in scaffolds is still lacking. Therefore, in this study, we fabricated piezoelectric scaffolds by functionalization of polycaprolactone-tricalcium phosphate (PCL-TCP) films with a polyvinylidene fluoride (PVDF) coating that is self-polarized by a modified breath-figure technique. The osteoinductive properties of these PVDF-coated PCL-TCP films on MC3T3-E1 cells were studied under the stimulation of PEMF. Piezoelectric and ferroelectric characterization demonstrated that scaffolds with piezoelectric coefficient d₃₃ = −1.2 pC/N were obtained at a powder dissolution temperature of 100 °C and coating relative humidity (RH) of 56%. DNA quantification showed that cell proliferation was significantly enhanced by PEMF as low as 0.6 mT and 50 Hz. Hydroxyapatite staining showed that cell mineralization was significantly enhanced by incorporation of PVDF coating. Gene expression study showed that the combination of PEMF and PVDF coating promoted late osteogenic gene expression marker most significantly. Collectively, our results suggest that the synergistic effects of PEMF and piezoelectric scaffolds on osteogenesis provide a promising alternative strategy for electrically augmented osteoinduction. The piezoelectric response of PVDF by PEMF, which could provide mechanical strain, is particularly interesting as it could deliver local mechanical stimulation to osteogenic cells using PEMF.

Decellularization is the process of obtaining acellular tissues with low immunogenic cellular components from animals or plants while maximizing the retention of the native extracellular matrix structure, mechanical integrity and bioactivity. The decellularized tissue obtained through the tissue decellularization technique retains the structure and bioactive components of its native tissue; it not only exhibits comparatively strong mechanical properties, low immunogenicity and good biocompatibility but also stimulates in situ neovascularization at the implantation site and regulates the polarization process of recruited macrophages, thereby promoting the regeneration of damaged tissue. Consequently, many commercial products have been developed as promising therapeutic strategies for the treatment of different tissue defects and lesions, such as wounds, dura, bone and cartilage defects, nerve injuries, myocardial infarction, urethral strictures, corneal blindness and other orthopedic applications. Recently, there has been a growing interest in the decellularization of fish tissues because of the abundance of sources, less religious constraints and risks of zoonosis transmission between mammals. In this review, we provide a complete overview of the state-of-the-art decellularization of fish tissues, including the organs and methods used to prepare acellular tissues. We enumerated common decellularized fish tissues from various fish organs, such as skin, scale, bladder, cartilage, heart and brain, and elaborated their different processing methods and tissue engineering applications. Furthermore, we presented the perspectives of (i) the future development direction of fish tissue decellularization technology, (ii) expanding the sources of decellularized tissue and (iii) innovating decellularized tissue bio-inks for 3D bioprinting to unleash the great potential of decellularized tissue in tissue engineering and regenerative medicine applications.

Bioinert poly(methyl methacrylate) (PMMA) is widely employed as a bone cement material in orthopedic and trauma surgery applications; however, its susceptibility to bacterial infection and bioinert nature limits its clinical applications. In this study, we developed a PMMA-based bone cement incorporating a silver nanoparticle-carbon dots (AgNP@CDs) nanocomposite (∼70 nm) at concentrations (2 wt%) with a Young’s modulus (324.74 ± 7.08 MPa) to simultaneously combat bacterial infections, minimize cytotoxicity and support tissue regeneration. The CDs stabilize and functionalize AgNPs, improving their dispersion and bioavailability while enabling the controlled and sustained release of antimicrobial ions through incorporation with bone cement. The antibacterial efficacy of the composite was thoroughly evaluated, revealing its ability to disrupt bacterial cell membranes, generate reactive oxygen species and inhibit bacterial growth. These mechanisms collectively contribute to a significant reduction in bacterial growth of up to ∼90% in both in vitro and in vivo studies. The incorporation of AgNP@CDs ensures sustained antimicrobial activity, preventing bacterial colonization by controlling the leaching of Ag ions. Biocompatibility assessments showed that the PMMA composite (PMMA@2Ag-CDs) significantly improved cell proliferation, adhesion and migration compared with pure PMMA bone cement. Additionally, histological analysis revealed that the PMMA group showed a fibrous layer thickness of 699 ± 35.32 µm, indicative of inflammation, while the PMMA@2Ag-CDs group reduced this thickness from 301.18 ± 22.42 µm on day 7 to 198.07 ± 15.21 µm on day 14, significantly decreasing inflammation. The PMMA@2Ag-CDs composite demonstrated better tissue integration, with organized collagen deposition and enhanced angiogenesis, indicating more efficient tissue regeneration. The reduced inflammation and improved tissue remodeling suggest that this composite promotes a more favorable tissue regeneration environment and minimizes complications. This study demonstrates that the PMMA@2Ag-CDs composite offers a promising solution for the prevention of infections and mitigation of inflammatory responses. Functionalization of bone cement through the incorporation of Ag nanoparticle-carbon dot nanocomposites is a promising strategy with potential practical applications in orthopedic and trauma surgery.