Deposition of Silicon-Based Stacked Layers for Flexible Encapsulation of Organic Light Emitting Diodes

In this study, inorganic silicon oxide (SiO_x)/organic silicon (SiC_xH_y) stacked layers were deposited by a radio frequency inductively coupled plasma chemical vapor deposition system as a gas diffusion barrier for organic light-emitting diodes (OLEDs). The effects of thicknesses of SiO_x and SiC_xH_y layers on the water vapor transmission rate (WVTR) and residual stress were investigated to evaluate the encapsulation capability. The experimental results showed that the lowest WVTR and residual stress were obtained when the thicknesses of SiO_x and SiC_xH_y were 300 and 30 nm, respectively. Finally, different numbers of stacked pairs of SiO_x/SiC_xH_y were applied to OLED encapsulation. The OLED encapsulated with the six-pair SiO_x/SiC_xH_y exhibited a low turn-on voltage and low series resistance, and device lifetime increased from 7 h to more than 2000 h.

Topical monomethylsilanetriol can deliver silicon to the viable skin

OBJECTIVE

Organic silicon has been linked to positive effects on the skin rejuvenation, mainly by the oral route. Thus, the main objective of the present study was to assess whether monomethylsilanetriol (MMST, a source of organic silicon) can deliver silicon to the epidermis and dermis, when applied topically in a cream. Once the hypothesis was confirmed, the present study also evaluated whether the product was toxic to keratinocytes; additionally, its possible antioxidant activity was assessed.

METHODS

The ex vivo skin permeation profile was determined using human skin in Franz-cells equipment; cytotoxicity was assessed using HaCaT keratinocytes. Antioxidant capacity was determined as scavenging activity, measured according to the 1,1-diphenyl-2-picrylhydrazil free radical method.

RESULTS

The permeation percentage was almost 60% of the applied MMST, with a large quantity of drug found in the viable epidermis and dermis. The cell viability assay showed no significant difference in the percentage of viable keratinocytes among the treated groups at the doses used. In terms of antioxidant activity, the IC₅₀ value obtained was 2400 μg mL^-1 . Low antioxidant activity, negligible toxicity for keratinocytes and a significant percentage of permeation were observed.

CONCLUSION

We provide evidence that MMST applied topically can deliver silicon to the skin in biorelevant levels for cosmetic purposes.

In vitro study of RRS® Silisorg CE Class III medical device composed of silanol: effect on human skin fibroblasts and its clinical use

Introduction

Silanol (organic silicon) has been used for decades in the treatment of skin photoaging as it stabilizes and maintains skin structures through hydrogen bonding electrostatic interaction with extracellular matrix (ECM) proteins or glycosaminoglycans. Organic silicon-based products are often presented as silanol derivatives which are currently associated to other structural molecules such as orthohydroxybenzoate, carboxymethyl theophylline alginate, ascorbate, acetyltyrosine, sodium lactate or mannuronate. Consequently, organic silicon formulations may differ substantially between the medical devices available on the market, which may result in additional effect on the skin. Therefore, there is a real need for a better characterization of the products in terms of their action on human skin and in vitro skin model.

Materials and methods

In this in vitro study, the effect of RRS® Silisorg was analyzed. RRS® Silisorg is a dermal implant (CE Class III medical device) containing monomethylsilanol mannuronate associated to an antioxidant resveratrol. Skin fibroblast viability and capacity to induce the production of key ECM genes were evaluated in the presence of different concentrations of RRS® Silisorg. The key ECM genes selected were collagen type I, elastin and hyaluronan synthase type 2 (HAS2), which is the cellular enzyme responsible for high-molecular weight hyaluronic acid (HA) production. Viability was evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and expression was quantified by quantitative polymerase chain reaction.

Results

RRS® Silisorg increased fibroblast gene expression of HAS2 in the first 24 hours, 25 times in the presence of 1 mg/mL of solution, followed by a collagen type I gene expression (4.7 times) and elastin expression (2.5 times) increase after 48 hours.

Conclusion

These results demonstrate that the silanol-based medical device RRS® Silisorg sustains HA, collagen and elastin production in human skin fibroblasts in vitro.