Manipulation and detection of single nanoparticles and biomolecules by a photonic nanojet.

Optical methods to manipulate and detect nanoscale objects are highly desired in both nanomaterials and molecular biology fields. Optical tweezers have been used to manipulate objects that range in size from a few hundred nanometres to several micrometres. The emergence of near-field methods that overcome the diffraction limit has enabled the manipulation of objects below 100 nm. A highly free manipulation with signal-enhanced real-time detection, however, remains a challenge for single sub-100-nm nanoparticles or biomolecules. Here we show an approach that uses a photonic nanojet to perform the manipulation and detection of single sub-100-nm objects. With the photonic nanojet generated by a dielectric microlens bound to an optical fibre probe, three-dimensional manipulations were achieved for a single 85-nm fluorescent polystyrene nanoparticle as well as for a plasmid DNA molecule. Backscattering and fluorescent signals were detected with the enhancement factors up to ∼103 and ∼30, respectively. The demonstrated approach provides a potentially powerful tool for nanostructure assembly, biosensing and single-biomolecule studies.

Topical tacalcitol and 308-nm monochromatic excimer light: a synergistic combination for the treatment of vitiligo.

BACKGROUND/PURPOSE: To study and compare the efficacy of combined 308-nm monochromatic excimer light (MEL) therapy with tacalcitol vs. that of MEL 308-nm therapy alone in treatment of vitiligo. METHODS: Thirty-eight patients with vitiligo were enrolled in a single-blind, within patient controlled clinical trial. Symmetrical or nearby lesions were randomly applied with either topical tacalcitol cream or vehicle. Each lesion was treated weekly with the 308-nm MEL, for a total of 12 sessions. Patients were examined at monthly intervals. The mean number of sessions and the cumulative dosage for initial repigmentation were calculated. RESULT: Thirty-five patients were evaluated. Treatment with tacalcitol and MEL resulted in higher percentages for excellent repigmentation (25.7%) compared with vehicle and MEL (5.7%) (P<0.05). Percentages for total response were 71.4% and 60%, respectively (P>0.05). The mean+/-SEM cumulative dose and number of excimer light exposures for initial repigmentation were, respectively, 3.93+/-0.59 J/cm2 and 4.52+/-0.49 at the tacalcitol side, and, respectively, 4.99+/-0.68 J/cm2 and 5.3+/-0.52 at the vehicle side (P<0.05). CONCLUSION: Our results have shown that concurrent topical tacalcitol potentiates the efficacy of the 308-nm MEL in the treatment of vitiligo, and that this combination achieves earlier pigmentation with a lower total dosage.

Topical tacalcitol and MEL308 nm:a synergistic combination for the treatment of vitiligo / 中华皮肤科杂志

Objective To study the efficacy and safety of tacalcitol combined with monochromatic excimer light (MEL) 308 nm vs MEL 308 nm monotherapy in treating vitiligo.Methods Thirty-eight pa- tients with vitiligo were enrolled in the single-blind clinical trial,using plabebo-treated lesions in the same patient as controls.Contralateral or nearby lesions were randomly selected to be treated by either tacalcitol or placebo.All lesions were treated weekly with MEL 308 nm,for a total of 12 sessions.Patients were ex- amined at monthly intervals.The mean number of sessions and the cumulative dosage for initial and excel- lent repigrnentation were calculated.Results Thirty-five patients were evaluated.The mean?SEM cumu- lative dose and number of MEL exposures for initial repigmentation,respectively,were 4.27?3.59 J/cm~2 and 4.89?3.16 on tacalcitol-treated site,5.36?4.12 J/cm~2 and 5.69?3.29 on placebo-treated site,re- spectively (both P＜0.05).For excellent repigrnentation,the cumulative dose and number of exposures were 7.72?5.64 J/cm~2 and 7.79?4.70 respectively on tacalcitol-treated site,and 8.18?4.87 J/cm~2 and 8.4?3.92 respectively on placebo-treated site (both P＞0.05).Treatment with tacalcitol resulted in a sig- nificantly higher percentage (71.4% vs 54.3%) of repigmentation than that with placebo.Conclusions Our results show that MEL 308 nm is safe and effective for the treatment of vitiligo.Additionally,concur- rent topical tacalcitol potentiates the efficacy of MEL 308 nm in the treatment of vitiligo;this combination achieves more rapid pigmentation with a lower total MEL dosage.