Hydroxyapatite (HA) has been widely applied in bone repair because of its superior biocompatibility. Recently, a proliferation-suppressive effect of HA nanoparticles (n-HA) against various cancer cells was reported. This study was aimed at assessing the translational value of n-HA both as a bone-regenerating material and as an antitumor agent. Inhibition of tumor growth, prevention of metastasis, and enhancement of the survival rate of tumor-bearing rabbits treated with n-HA were demonstrated. Activated mitochondrial-dependent apoptosis in vivo was confirmed, and we observed that a stimulated immune response was involved in the n-HA–induced antitumor effect. A porous titanium scaffold loaded with n-HA was fabricated and implanted into a critical-sized segmental bone defect in a rabbit tumor model. The n-HA–releasing scaffold not only showed a prominent effect in suppressing tumor growth and osteolytic lesion but also promoted bone regeneration. These findings provide a rationale for using n-HA in tumor-associated bone segmental defects.
Bulk nanocrystalline Ti bars (Grade 4, Φ4 × 3000 mm(3)) were massively fabricated by equal channel angular pressing (ECAP) via follow-up conform scheme with the microcrystalline CP Ti as raw material. Homogeneous nanostructured crystals with the average grain size of 250 nm were identified for the ECAPed Ti, with extremely high tensile/fatigue strength (around 1240/620 MPa) and adorable elongation (more than 5%). Pronounced formation of bonelike apatite for the nanocrystalline Ti group after 14 days static immersion in simulated body fluids (SBF) reveals the prospective in vitro bioactive capability of fast calcification, whereas an estimated 17% increment in protein adsorption represents good bioaffinity of nanocrystalline Ti. The documentation onto the whole life circle of osteoblast cell lines (MG63) revealed the strong interactions and superior cellular functionalization when they are co-incubated with bulk nanocrystalline Ti sample. Moreover, thread-structured specimens were designed and implanted into the tibia of Beagles dogs till 12 weeks to study the in vivo responses between bone and metallic implant made of bulk nanocrystalline Ti, with the microcrystalline Ti as control. For the implanted nanostructured Ti group, neoformed bone around the implants underwent the whole-stage transformation proceeding from originally osteons or immature woven bone to mature lamellar bone (skeletonic trabecular), even with the remodeling being finished till 12 weeks. The phenomenal osseointegration of direct implant-bone contact can be revealed from the group of the ECAPed Ti without fibrous tissue encapsulation in the gap between the implant and autogenous bone.
Tantalum (Ta) metal is receiving increasing interest as biomaterial for load-bearing orthopedic applications and the synthetic properties of Ta can be tailored by altering its grain structures. This study evaluates the capability of sliding friction treatment (SFT) technique to modulate the comprehensive performances of pure Ta. Specifically, novel nanocrystalline (NC) surface with extremely small grains (average grain size of ≤20 nm) was fabricated on conventional coarse-grained (CG) Ta by SFT. It shows that NC surface possessed higher surface hydrophilicity and enhanced corrosion resistance than CG surface. Additionally, the NC surface adsorbed a notably higher percentage of protein as compared to CG surface. The in vitro results indicated that in the initial culture stages (up to 24 h), the NC surface exhibited considerably enhanced osteoblast adherence and spreading, consistent with demonstrated superior hydrophilicity on NC surface. Furthermore, within the 14 days culture period, NC Ta surface exhibited a remarkable enhancement in osteoblast cell proliferation, maturation and mineralization as compared to CG surface. Ultimately, the improved osteoblast functions together with the good mechanical and anti-corrosion properties render the SFT-processed Ta a promising alternative for the load-bearing bone implant applications.
Hybrid organic–inorganic perovskite (HOP) spintronics aims to make full use of the properties of electron spin. HOP spintronics has recently emerged as a promising field of research because it provides a new precisely manipulable degree of freedom. The flourishing development activity in this field has benefited from the unique intrinsic spin‐related optoelectronic properties of HOPs, which include triplet formation, a large Stark effect, the magneto‐optical effect, polarized light‐related effects, and complex light emission characteristics, which offer the possibility of providing a new way to control the performance of integrated optoelectronic devices through spin interactions between photons and electrons. Along with the continuous improvements in the theoretical research into HOP spintronics, large numbers of novel optoelectronic devices have been proposed and demonstrated experimentally and have shown great potential for fabrication of next‐generation, high‐performance integrated optoelectronic chips. This review provides an overview of the fundamental principles, novel spin‐generated physical effects, and diverse structures of HOP spintronics systems, along with the applications of HOP spintronics in optoelectronic devices, while also undertaking a general review of the remaining challenges and proposing possible development directions that require further study for the application of HOP spintronics to integrated optoelectronic devices.
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