Anti-infective composite cryogel scaffold treats osteomyelitis and augments bone healing in rat femoral condyle

Dielectric and Magnetic Composites of Fe3O4@APNs for Superior Microwave Thermal Effect

As for the deep tissue infections of chronic osteomyelitis, antibiotics are hard to deliver into the infected bone tissue, which makes it difficult to be cured completely in clinic. Microwave has strong penetration, and the medium can produce a good bactericidal effect through the microwave thermal effect (MTE). Here, a new microwave sensitizer (Fe3O4@APNs) was prepared and evaluated. Black phosphorus nanosheets modified with phytic acid dodecasodium (APNs) were fabricated by a liquid-phase exfoliation method that exhibited good water oxygen stability. A complex with Fe3O4 compound and APNs (Fe3O4@APNs) was formed by an ultrasonic mixing process, which showed excellent MTE (quickly increased to 53.5 °C in 5 min at 2.45 GHz, 10 W/cm2) via dielectric versus magnetic loss (reflect loss value of -5.94 dB at 2.45 GHz). The Fe3O4@APNs microwave sensitizer developed in this study has an outstanding in vitro antibacterial effect and might show promise for the treatment of chronic osteomyelitis enabled by local tissue heating via the MTE.

Organic-inorganic composite of polypropylene fumarate and nanohydroxyapatite as carrier of antibiotics for the treatment of bone infections

Current treatment approaches in clinics to treat the infectious lesions have partial success thus demanding the need for development of advanced treatment modalities. In this study we fabricated an organic-inorganic composite of polypropylene fumarate (PPF) and nanohydroxyapatite (nHAP) by photo-crosslinking as a carrier of two clinically used antibiotics, ciprofloxacin (CIP) and rifampicin (RFP) for the treatment of bone infections. Carboxy terminal-PPF was first synthesized by cis-trans isomerization of maleic anhydride which was then photo-crosslinked using diethylfumarate (DEF) as crosslinker and bis-acylphosphine oxide (BAPO) as photo-initiator under UV lights (P). A composite of PPF and nHAP was fabricated by incorporating 40 % of nHAP in the polymeric matrix of PPF (PH) which was then characterized for different physicochemical parameters. CIP was added along with nHAP to fabricated CIPloaded composite scaffolds (PHC) which was then coated with RFP to synthesize RFP coated CIP-loaded scaffolds (PHCR). It was observed that there was a temporal separation in the in vitro release of two antibiotics after coating PHC with RFP with 80.48 ± 0.40 % release of CIP from PHC and 62.43 ± 0.21 % release of CIP from PHCR for a period of 60 days. Moreover, in vitro protein adsorption was also found to be maximum in PHCR (154.95 ± 0.07 μg/mL) as observed in PHC (75.42 ± 0.06 μg/mL), PH (24.47 ± 0.08 μg/mL) and P alone (4.47 ± 0.02 μg/mL). The scaffolds were also evaluated using in vivo infection model to assess their capacity in reducing the bacterial burden at the infection site. The outcome of this study suggests that RFP coated CIP-loaded PPF composite scaffolds could reduce bacterial burden and simultaneously augment bone healing during infection related fractures.

Cryogels: Advancing Biomaterials for Transformative Biomedical Applications

Cryogels, composed of synthetic and natural materials, have emerged as versatile biomaterials with applications in tissue engineering, controlled drug delivery, regenerative medicine, and therapeutics. However, optimizing cryogel properties, such as mechanical strength and release profiles, remains challenging. To advance the field, researchers are exploring advanced manufacturing techniques, biomimetic design, and addressing long-term stability. Combination therapies and drug delivery systems using cryogels show promise. In vivo evaluation and clinical trials are crucial for safety and efficacy. Overcoming practical challenges, including scalability, structural integrity, mass transfer constraints, biocompatibility, seamless integration, and cost-effectiveness, is essential. By addressing these challenges, cryogels can transform biomedical applications with innovative biomaterials.

Biofunctionalization with Cissus quadrangularis Phytobioactives Accentuates Nano-Hydroxyapatite Based Ceramic Nano-Cement for Neo-Bone Formation in Critical Sized Bone Defect

Developing biofunctionalized ceramic bone substitutes with phytobioactives for their sustained delivery is highly desired to enhance the osteo-active potential of ceramic bone substitutes, reduce the systemic toxicity of synthetic drugs, and increase the bioavailability of phytobioactives. The present work highlights the local delivery of phytobioactives of Cissus quadrangularis (CQ) through nano-hydroxyapatite (nHAP) based ceramic nano-cement. The phytoconstituent profiling represented the optimized CQ fraction to be rich in osteogenic polyphenols and flavonoids like quercetin, resveratrol, and their glucosides. Further, CQ phytobioactives-based formulation was biocompatible, increased bone formation, calcium deposition, proliferation, and migration of cells with simultaneous alleviation of cellular oxidative stress. In the in vivo critical-sized bone defect model, enhanced formation of highly mineralized tissue (BV mm³) in CQ phytobioactives functionalized nano-cement (10.5 ± 2 mm³) were observed compared to the control group (6.5 ± 1.2 mm³). Moreover, the addition of CQ phytobioactives to the bone nano-cement increased the fractional bone volume (BV/TV%) to 21 ± 4.2% compared to 13.1 ± 2.5% in non-functionalized nano-cement. The results demonstrated nHAP-based nano-cement as a carrier for phytobioactives which could be a promising approach for neo-bone formation in different bone defect conditions.