The impact of photofunctionalized gold nanoparticles on osseointegration

Photofunctionalization of Dental Implant Surfaces - A Histomorphometric Animal Study

Aims

To compare and evaluate the degree of osseointegration of UV-treated (photo functionalized) and non-treated dental implants surface coated with Calcium phosphate using the Resorbable Blast Media (RBM) technique in an animal model.

Settings and Design

Evaluative-Animal study design.

Materials and Methods

Six titanium dental implants of diameter 3.2 mm and length of 8 mm with Calcium phosphate coated surface using RBM or resorbable blast media technology (Implant Genesis: Genesis Normo Implant system) were placed epicrestally into the proximal femoral condyle of New Zealand white female rabbits such that each animal received two implants. Before implantation, one out of the two dental implants was photo functionalized with intense UV light for 15 minutes. After twelve weeks of healing, the animals were euthanized and the harvested specimens were analyzed using histomorphometric light microscopy to assess two parameters bone-implant contact and bone volume density.

Statistical Analysis Used

SPSS version 23. P less than 0.05 is considered statistically significant. Tests used ANOVA followed by Tukey post hoc test.

Results

All six dental implants were osseointegrated. The overall mean bone-implant contact area (BIC) was 57.76% for non-UV treated whereas 88.4367% for UV-treated dental implants. The overall mean bone volume density (BVD) was 32.2333% for non-UV treated whereas 67.7533% for UV-treated dental implants.

Conclusion

Significant effects were observed on the osseointegration of dental titanium implants within twelve weeks after UV photo functionalization. The UV photo functionalization of dental titanium implants in the current study significantly altered the BIC and bone density on osseointegration when observed over twelve weeks.

Gold nanoparticles: promising biomaterials for osteogenic/adipogenic regulation in bone repair

Bone defects are a common bone disease, which are usually caused by accidents, trauma and tumors. However, the treatment of bone defects is still a great clinical challenge. In recent years, research on bone repair materials has continued with great success, but there are few reports on the repair of bone defects at a high lipid level. Hyperlipidemia is a risk factor in the process of bone defect repair, which has a negative impact on the process of osteogenesis, increasing the difficulty of bone defect repair. Therefore, it is necessary to find materials that can promote bone defect repair under the condition of hyperlipidemia. Gold nanoparticles (AuNPs) have been applied in the fields of biology and clinical medicine for many years and developed to modulate osteogenic differentiation and adipogenic differentiation. In vitro and vivo studies displayed that they promoted bone formation and inhibited fat accumulation. Further, the metabolism and mechanisms of AuNPs acting on osteogenesis/adipogenesis were partially revealed by researchers. This review further clarifies the role of AuNPs in osteogenic/adipogenic regulation during the process of osteogenesis and bone regeneration by summarizing the related in vitro and in vivo research, discussing the advantages and challenges of AuNPs and highlighting several possible directions for future research, with the aim to provide a new strategy for dealing with bone defects in hyperlipidemic patients.

Anti-bacterial activity of gold nanocomposites as a new nanomaterial weapon to combat photogenic agents: recent advances and challenges

Gold nanocomposites are being widely used in numerous biomedical applications owing to their excellent stability and miniaturization. Gold nanocomposites are notable because of their flexibility of functionalization and synthesis, ease of detection, and low toxicity. Cost-effectiveness, long-term stability, non-cytotoxicity, and biocompatibility are the main aspects of ideal nanocomposites. Antibacterial nanocomposites are being developed extensively in the food industry, environmental applications, and biological and medical devices. This review focuses on the applications of metal-based nanoparticles, mainly gold nanoparticles (AuNPs), as antibacterial agents in medical approaches. Additionally, the antibacterial mechanisms of AuNPs and their roles in fighting antibiotic-resistant microorganisms are highlighted in the present review.

Gold nanocomposites are being widely used in numerous biomedical applications owing to their excellent stability and miniaturization.

Effect of focal adhesion kinase inhibition on osteoblastic cells grown on titanium with different topographies

Objective

The present study aimed to investigate the participation of focal adhesion kinases (FAK) in interactions between osteoblastic cells and titanium (Ti) surfaces with three different topographies, namely, untreated (US), microstructured (MS), and nanostructured (NS).

Methodology

Osteoblasts harvested from the calvarial bones of 3-day-old rats were cultured on US, MS and NS discs in the presence of PF-573228 (FAK inhibitor) to evaluate osteoblastic differentiation. After 24 h, we evaluated osteoblast morphology and vinculin expression, and on day 10, the following parameters: gene expression of osteoblastic markers and integrin signaling components, FAK protein expression and alkaline phosphatase (ALP) activity. A smooth surface, porosities at the microscale level, and nanocavities were observed in US, MS, and NS, respectively.

Results

FAK inhibition decreased the number of filopodia in cells grown on US and MS compared with that in NS. FAK inhibition decreased the gene expression of Alp, bone sialoprotein, osteocalcin, and ALP activity in cells grown on all evaluated surfaces. FAK inhibition did not affect the gene expression of Fak, integrin alpha 1 ( Itga1 ) and integrin beta 1 ( Itgb1 ) in cells grown on MS, increased the gene expression of Fak in cells grown on NS, and increased the gene expression of Itga1 and Itgb1 in cells grown on US and NS. Moreover, FAK protein expression decreased in cells cultured on US but increased in cells cultured on MS and NS after FAK inhibition; no difference in the expression of vinculin was observed among cells grown on all surfaces.

Conclusions

Our data demonstrate the relevance of FAK in the interactions between osteoblastic cells and Ti surfaces regardless of surface topography. Nanotopography positively regulated FAK expression and integrin signaling pathway components during osteoblast differentiation. In this context, the development of Ti surfaces with the ability to upregulate FAK activity could positively impact the process of implant osseointegration.