ABSTRACT
To investigate the crucial role of particle size in the biological effects of nanoparticles, a series of mesoporous silica nanoparticles (MSNs) were prepared with particle size gradients (50, 100, 150, 200 nm) with the traditional Stober method and adjusting the type and ratio of the silica source. The correlation between toxicity and size-caused biological effects were then further examined both in vitro and in vivo. The results indicated that the prepared MSNs had a uniform size, good dispersal, and ordered mesoporous structure. Hemolytic toxicity was found to be independent of particle size. At the cellular level, MSNs with smaller particle sizes were more readily internalized by cells, which initiated to more intense oxidative stress, therefor inducing higher cytotoxicity, and apoptosis rate. In vivo studies demonstrated that MSNs primarily accumulated in the liver and kidneys of mice. Pharmacokinetic analysis revealed that larger MSNs were eliminated more efficiently by the urinary system than smaller MSNs. The mice's body weight monitoring, blood tests, and pathological sections of major organs indicated good biocompatibility for MSNs of different sizes. Animal welfare and the animal experimental protocols were strictly consistent with related ethics regulations of Zhejiang Chinese Medical University. Overall, this study prepared MSNs with a particle size gradient to investigate the correlation between toxicity and particle size using macrophages and endothelial cells. The study also examined the biosafety of MSNs with different particle sizes in vivo and in vitro, which could help to improve the safety design strategy of MSNs for drug delivery systems.
ABSTRACT
<p><b>OBJECTIVE</b>To analyze the effect of biomechanical reconstruction of the hip in metal-on-metal total hip resurfacing.</p><p><b>METHODS</b>Thirty patients undergoing hip resurfacing arthroplasties were enrolled in this study. The clinical outcomes of the patients were assessed according to the Harris Hip Score before and after the surgery, X-ray examinations and biomechanical reconstruction evaluations.</p><p><b>RESULTS</b>After the operation, the length of the patients' legs was shortened by a mean of 2.4 mm. and the femoral offset was decreased by a mean of 5.45 mm. No dislocation were be found in these patients. The preoperative Harris Hip Score was 36.69-/+7.16, significantly lower than that postoperative score (89.63-/+3.36, P<0.01).</p><p><b>CONCLUSION</b>Precise biomechanical reconstruction of the hip can be achieved in hip resurfacing arthroplasty, and the stability and functional restoration is guaranteed by large diameter prosthesis design.</p>