Fringe Dielectrophoresis Nanoaperture Optical Trapping with Order of Magnitude Speed-Up for Unmodified Proteins

Single molecule analysis of proteins in an aqueous environment without modification (e.g., labels or tethers) elucidates their biophysics and interactions relevant to drug discovery. By combining fringe-field dielectrophoresis with nanoaperture optical tweezers we demonstrate an order of magnitude faster time-to-trap for proteins when the counter electrode is outside of the solution. When the counter electrode is inside the solution (the more common configuration found in the literature), electrophoresis speeds up the trapping of polystyrene nanospheres, but this was not effective for proteins in general. Since time-to-trap is critical for high-thoughput analysis, these findings are a major advancement to the nanoaperture optical trapping technique for protein analysis.

Accessible high-performance double nanohole tweezers

Nanohole optical tweezers have been used by several groups to trap and analyze proteins. In this work, we demonstrate that it is possible to create high-performance double nanohole (DNH) substrates for trapping proteins without the need for any top-down approaches (such as electron microscopy or focused-ion beam milling). Using polarization analysis, we identify DNHs as well as determine their orientation and then use them for trapping. We are also able to identify other hole configurations, such as single, trimers and other clusters. We explore changing the substrate from glass to polyvinyl chloride to enhance trapping ability, showing 7 times lower minimum trapping power, which we believe is due to reduced surface repulsion. Finally, we present tape exfoliation as a means to expose DNHs without damaging sonication or chemical methods. Overall, these approaches make high quality optical trapping using DNH structures accessible to a broad scientific community.

Evaluation of 1,25-dihydroxyvitamin D3 pathway in patients with chronic urticaria

BACKGROUND

Previous studies showed the role of vitamin D (Vit D) on the progression of chronic urticaria. To the best of our knowledge, there are no other results regarding the contribution of single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) and vitamin D binding protein (VDBP) genes in chronic urticaria (CU).

AIM

In the present study, we investigated the Vit pathway and the association between VDR and VDBP gene polymorphisms and CU risk in Iranian population.

METHODS

All participating individuals in the present study were evaluated for serum Vit D and VDBP concentration VDR rs1544410 and rs2228570 and VDBP rs7041using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The associations of studied analytes and three SNPs with clinical and laboratory outcomes were investigated in CU patients.

RESULTS

Patients with CU showed lower Vit D compared to controls (19.26 ± 1.26 vs. 31.72 ± 7.14 ng/ml, P-value = 0.006). There was a significant correlation between Vit D levels and urticaria activity score. Serum VDBP was significantly higher in CU patients than controls (1317.3 ± 183.71 vs. 395.77 ± 12.96 µg/ml, P-value <0.0001) and had a positive correlation to progression of CU. The A allele of this polymorphism might be a potential risk factor for progression of CU [odds ratio 4.3434, 95% confidence interval (1.7331-10.8852), Z-statistic = 3.133, P-value = 0.0017].

CONCLUSION

In summary, this study demonstrated that change in Vit D pathway in the level of gene or protein may be a risk factor for progression of CU.

An investigation of the inhibitory effects of dendrosomal nanocurcumin on Candida albicans and systemic candidiasis in BALB/c mice

Background and Purpose:

Use of curcumin, as a promising antifungal agent, is considered an alternative treatment for fungal infections; however, the low solubility of this agent limits its efficacy. Accordingly, in this study, we aimed to evaluate the in vitro and in vivo antifungal activities of dendrosomal nanocurcumin with improved solubility and bioavailability.

Materials and Methods:

The in vitro antifungal activities of several Candida species, including C. albicans, C. tropicalis, C. krusei, C. parapsilosis , and C. dubliniensis, were evaluated, using the broth microdilution method. In the in vivo study, different doses of nanocurcumin (5, 10, 20, and 40 mg/kg) were administered to mice with systemic C. albicans infection via intraperitoneal injection. All mice were euthanized at 20 days following the administration of different doses of nanocurcumin. Different organs were extracted for organ culture and histopathological investigation.

Results:

Based on the findings, 40 mg/kg of nanocurcumin significantly decreased the fungal load in the evaluated organs; the results were confirmed with histopathological examination. The kidney was found to be the most affected organ with the highest number of severe lesions. Yeasts and pseudohyphae were observed in the blood vessels, kidney, and brain. Also, yeasts were present in the liver, brain, lungs, and heart of the control group.

Conclusion:

Although curcumin is generally an excellent antifungal component, its nano-sized form showed more potent properties. Based on the gathered data, dendrosomal nanocurcumin is an effective antifungal agent with good efficacy against disseminated candidiasis. However, further studies are required to evaluate the effects of dendrosomal nanocurcumin on other fungal infections. Also, this agent could be useful for the prevention of fungal infections, such as candidiasis, particularly in high-risk patients.