Wild Plum, Nano Self-assembly Delivery, Rice Leaf Self-cleansing and More

Blue fluorescent compounds to restore luminosity in sun-exposed skin

C Reicks, J Groathouse, M Trauernicht, S Sikich, MV Wilson, AE Holmes and AJ Jackson; Aug. 7, 2012 (online), Feb. 2013 (print), Skin Research and Technology

Work published in Skin Research and Technology describes blue fluorescent solids, referred to as wild plum compounds, that camouflage skin imperfections when incorporated into cosmetics. The authors first evaluated the connection between sun exposure and skin fluorescence, then determined whether the application of wild plum-containing products restored lost fluorescence to skin.

The forehead skin of two groups of volunteers, of mixed gender and age, was evaluated for fluorescence and redness. In addition, subjects answered questions describing any adverse sensations after being exposed to wild plum formulations. Fluorescence measurements of both sun-exposed and non-sun-exposed skin indicated that repeated exposure causes a loss of skin fluorescence; however, application of wild plum-comtaining formulations restored the fluorescence of sun-exposed skin to values beyond that of non-exposed skin. Further, photo analysis and questionnaires indicated that the formulations did not cause irritancy. And although the micrometer size is large enough to prevent skin penetration, it reportedly is still small enough to avoid graininess in the formulation.

Self-assembling nanostructures for improved efficacy

AG Cheetham, P Zhang, Y Lin, LL Lock and H Cui; Feb 4, 2013 (online); J Am Chem Soc

A report by the National Science Foundation (NSF) explains that nanoparticles have been used to transport chemotherapy drugs to target cancer cells while sparing normal cells. However, the amount of drug loaded into these carriers is difficult to control. Therefore, an ideal scenario would be to turn the drugs into their own delivery systems, eliminating the synthetic vehicles altogether. A team of anti-cancer researchers, funded by NSF, from Johns Hopkins University is working toward this end, and has published work in the Journal of the American Chemical Society on an approach to enable the hydrophobic anticancer drug camptothecin (CPT) to self-assemble into stable, well-defined nanostructures. These structures can be loaded at 23% to 38%, and designed so that under the right conditions, they release their content.

According to the NSF report, in order for the drug to become its own nano-scale delivery system, it must act in such a way to draw molecules together to form a nanostructure, yet maintain its solubility in aqueous solution. To make the drug more hydrophilic, the researchers are working with water-soluble peptides, incorporating them into the drugs via biodegradable linkers, so they become self-assembling. In an interview by NSF with Honggang Cui, researcher on the project, Cui envisioned eventually altering the peptide sequence to control its size, shape and surface chemistry, to create different drug sizes and shapes for a given target.

Rice leaves and butterfly wings for self-cleaning

GD Bixler and B Bhushan; Sept. 11, 2012 (online); Soft Matter; and 2013 accepted manuscript; Nanoscale

Researchers at Ohio State University are looking to the low adhesion surface characteristics of rice leaves and butterfly wings for self-cleaning answers. Using combinations of actual and replica samples, some based on shark skin and lotus flowers, the researchers sought to replicate these characteristics by giving the samples a superhydrophobic and low adhesion nanostructured coating. Their work, published in Soft Matter, discusses how shark skin—with its anisotropic flow and low drag, and lotus—with its hydrophobic and self-cleaning effects, can serve as conceptual models for self-cleaning and antifouling properties.

In relation, the same authors will explore rice leaf and butterfly wing fluid drag and self-cleaning properties in studies yet to be published in Nanoscale in 2013. Fish scales and shark skin also are studied, and data on morphology, drag, self-cleaning, contact angle and contact angle hysteresis presented, in attempt to understand wettability, viscosity and velocity. Liquid repellent coatings are then utilized to recreate or combine these various effects, and explored for applications in the medical, marine, and industrial fields.

Ingenol mebutate gel for effective, sustained acne treatment

M Lebwohl, S Shumack, L Stein Gold, A Melgaard, T Larsson and SK Tyring; March 20, 2013 (online); JAMA Derm Recent research published in the JAMA describes a 12-month study of subjects after they received treatment for, and clearance of, actinic keratoses. Subjects initially were treated with ingenol mebutate, a macrocyclic diterpene ester from the sap of Euphorbia peplus, and were then re-assessed for recurrence rates and safety. According to the article abstract, 100 patients cleared from acne of the face or scalp, and 71 patients cleared from acne of the trunk or extremities, completed the study.

Sustained lesion reduction rates, compared with baseline, were 87.2% for the face or scalp and 86.8% for the trunk or extremities. The estimated average times to recurrence were 365 days for the face or scalp, and 274 days for the trunk or extremities. There were also no safety concerns found during the follow-up period. The authors concluded that ingenol mebutate gel, applied for two or three consecutive days to treat actinic keratoses, produced clinically relevant and sustained clearance and long-term lesion reduction.

Metabolic effects of TiO2 nanoparticles

P Tucci, G Porta, M Agostini, D Dinsdale, I Iavicoli, K Cain, A Finazzi-Agró, G Melino and A Willis; Jan. 29, 2013; Cell Death and Disease

According to a paper published in Cell Death and Disease, the extent to which nanoparticle compounds contribute to cellular toxicity is unclear. Although they are associated with the induction of oxidative stress pathways related to this process, the specific proteins and the metabolic pathways involved are largely unknown. To investigate this, the authors studied the effects of TiO2 on the HaCaT human keratinocyte cell line. Results showed that although TiO2 did not affect cell cycle phase distribution, nor cell death, the nanoparticles did have a considerable and rapid effect on mitochondrial function. Importantly, the uptake of nanoparticles into the cultured cells was restricted to phagosomes, and TiO2 nanoparticles did not enter into the nucleus or any other cytoplasmic organelles. Further, no other morphological changes were detected after 24 hr.

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