The regeneration of complex bone defects remains a major challenge in orthopedics and trauma surgery, particularly when anatomical intricacy or limited structural support is involved. Traditional rigid implants often fail to conform to irregular defect geometries, while non-structural grafts lack the mechanical integrity needed for load-bearing sites. To address these limitations, this study focuses on designing an injectable, photocurable polyanhydride-based scaffold reinforced with hydroxyapatite-collagen nanoparticles doped with bioactive ions—silicon (Si) and strontium (Sr)—to achieve both structural stability and enhanced biological performance.
The scaffold system was developed using methacrylated monomers: sebacic acid dimethacrylate (MSA) and 1,6-bis(p-carboxyphenoxy)hexane (MCPH), blended with poly(ethylene glycol) diacrylate (PEGDA) as a crosslinker. These components were formulated into a viscous paste that undergoes rapid photopolymerization upon exposure to UV light (365 nm). A dual initiator system—camphorquinone (CQ)/ethyl 4-(dimethylamino)benzoate (4EDMAB) for photo-initiation and benzoyl peroxide (BPO)/dimethyl toluidine (DMT) for chemical initiation—ensured complete curing within minutes, enabling clinical feasibility for minimally invasive delivery.
Hydroxyapatite-collagen nanoparticles were synthesized via co-precipitation, followed by doping with either 1 wt% Si⁴⁺, 1 wt% Sr²⁺, or 0.5 wt% Si + 0.5 wt% Sr. The resulting nanocomposites were uniformly incorporated at 10 wt% into the polymer matrix prior to crosslinking. Characterization through X-ray diffraction confirmed the presence of carbonated hydroxyapatite with low crystallinity, consistent with natural bone mineral. Transmission electron microscopy revealed spherical to rod-like nanoparticle morphologies (40–80 nm) with homogeneous distribution throughout the matrix. Energy-dispersive X-ray analysis confirmed successful incorporation of dopants without phase segregation.
Mechanical evaluation demonstrated that the addition of 10 wt% doped nanoparticles significantly improved compressive strength from 30 MPa (pure polyanhydride) to 49 ± 3.8 MPa in the composite, surpassing trabecular bone values and approaching those of cortical bone. While no significant differences were observed among the doped variants, the overall enhancement underscored the critical role of ceramic reinforcement in mechanical performance.RIPK1 Antibody custom synthesis
In vitro cell culture studies used human umbilical cord-derived mesenchymal stem cells (MSCs) seeded onto the hardened scaffolds. After 11 days, MTT assay showed the highest metabolic activity and proliferation rate in the Si-Sr co-doped group, indicating superior biocompatibility and bioactivity. Confocal imaging revealed the most intense osteocalcin expression in this sample, confirming accelerated osteogenic differentiation. Additionally, MSCs exhibited enhanced spreading and lamellipodia formation on the doped scaffolds, suggesting favorable integrin-mediated adhesion.
The synergistic action of Si and Sr ions plays a crucial role in bone regeneration. Silicon promotes early apatite nucleation and upregulates genes associated with osteoblast maturation, while strontium enhances alkaline phosphatase activity and stimulates osteogenesis while suppressing bone resorption.ALDH3A2 Antibody MedChemExpress Their controlled release from the surface-eroding polyanhydride matrix provides a sustained biochemical signal conducive to tissue remodeling.PMID:34968554
This study demonstrates that photocurable polyanhydride scaffolds incorporating Si- and Sr-doped hydroxyapatite-collagen nanoparticles offer a promising solution for bone substitution. The material combines injectability, rapid hardening, tunable degradation, high compressive strength, and potent osteoinductive capacity. It is particularly suited for applications requiring precise placement in irregular or inaccessible skeletal sites, such as spinal fusion, craniofacial reconstruction, and segmental bone loss. Future work will focus on in vivo validation and long-term degradation behavior to assess clinical translation potential.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com