Silicone Polymers in Scar Remediation: The Role of Migration of Oligomers Through Stratum Corneum

2005 ◽  
Vol 58 (6) ◽  
pp. 447 ◽  
Author(s):  
Washington Sanchez ◽  
John Evans ◽  
Graeme George
Keyword(s):  
Stratum Corneum ◽  
Attenuated Total Reflection ◽  
Aqueous Environment ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Breakthrough Time ◽  
Silicone Gel ◽  
Silicone Polymers ◽  
Hydrophobic Solutes

A cross-linked silicone gel for burns scar rehabilitation has been analyzed to determine the oligomeric species that may migrate from the gel into skin. From MALDI–MS (matrix assisted laser desorption ionization–mass spectrometry) these were shown to be hydroxyl-terminated linear oligomers with a mass of up to 2100 Da. The migration of the extracted oligomers through stratum corneum has been determined by breakthrough times using ATR–FTIR (attenuated total reflection Fourier-transform infrared) spectroscopy. The upper value of the estimated diffusion coefficient of 2.5 × 10−9 cm2 s−1, determined from a breakthrough time of 31 h, is similar to that of large hydrophobic solutes, but penetration times from the silicone gel are low (7–10 days) due to the lower concentration of oligomers partitioning into the lipid bilayer of the skin in an aqueous environment.

scholarly journals Skin Electrical Resistance Measurement of Oxygen-Containing Terpenes as Penetration Enhancers: Role of Stratum Corneum Lipids

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 523 ◽  
Author(s):  
Xue-min Zhu ◽  
Yu Li ◽  
Fei Xu ◽  
Wei Gu ◽  
Guo-jun Yan ◽  
...  
Keyword(s):  
Stratum Corneum ◽  
Electrical Resistance ◽  
Attenuated Total Reflection ◽  
Penetration Enhancers ◽  
Rapid Screening ◽  
Factors Affecting ◽  
Skin Cell ◽  
First Time

The measurement of skin electrical resistance (SER) has drawn a great deal of attention for the rapid screening of transdermal penetration enhancers (PEs). However, the mechanisms underlying the SER measurement are still unclear. This study was to investigate the effects and mechanisms of seven oxygen-containing terpenes on the SER kinetics. Stratum corneum (SC) lipids were proved to play a key role in SER measurement. Then, the factors affecting the SER measurement were optimized. By the determination of SER kinetics, cyclic terpenes (1,8-cineole, terpinen-4-ol, menthol and α-terpineol) were demonstrated to possess higher enhancement ratio (ER) values compared with linear terpenes (linalool, geraniol and citral). For the first time, the linear correlation was found between ER of terpenes and the interaction energy of terpene–ceramide complexes revealed by molecular simulation. The attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) analysis revealed that the effect of cyclic terpenes on SC lipid arrangement was obviously stronger than that of linear terpenes. In addition, by evaluating HaCaT skin cell viability, little difference was found between the toxicities of cyclic and linear terpenes. In conclusion, measurement of SER could be a feasible approach for the efficient evaluation of the PEs that mainly act on SC lipids.

Does Silicone Gel Migrate Via Lymphatics After Subcutaneous Injection?

1994 ◽  
Vol 2 (2) ◽  
pp. 67-70
Author(s):  
Philip P Narini ◽  
John L Semple ◽  
John B Hay ◽  
Stan J Lugowski ◽  
Dennis Smith
Keyword(s):  
Lymph Nodes ◽  
Subcutaneous Injection ◽  
Trace Element Analysis ◽  
Lymphatic Vessels ◽  
Elemental Silicon ◽  
Element Analysis ◽  
Sheep Model ◽  
Silicone Gel ◽  
Silicone Polymers

PP Narini, JL Semple, JB Hay, SJ Lugowski, D Smith. Does silicone gel migrate via lymphatics after subcutaneous injection? Can J Plast Surg 1994;2(2):67-70. Reports have documented the presence of elemental silicon, evidence of silicone elastomer, or silicone polymers (gel) in lymph nodes and other sites distant from implanted prostheses. It has been suggested that this occurs via the lymphatic system; however, the mechanism of spread or migration of silicone has not been previously studied. This study investigated the possible role of lymphatics in the migration of silicone gel. In the sheep model, it is possible to obtain continuous samples of both afferent and efferent lymph by cannulating lymphatic vessels. The drainage areas of subcutaneous lymph nodes in the sheep have previously been studied. In our model, the efferent lymphatic vessel from the prefemoral lymph node was cannulated to obtain samples of lymph (efferent and ‘pseudoafferent’). After baseline samples were collected, 3 to 5 mL of free silicone gel was injected subcutaneously in the drainage area of this node. Samples (5 to 10 ml.) of lymph were continuously collected (for up to 50 days), sealed, stored at −20°C, and then submitted as a group for trace element analysis to quantitate the levels of elemental silicon. No statistically significant increase was seen in baseline levels of elemental silicon after silicone gel injections. Statistically significant higher levels of silicon were found in afferent (mean 799 ± 22 part per billion [ppb]) compared with efferent lymph (mean 607 ± 19 ppb). This experimental study did not identify significant increases in elemental silicon levels in lymphatic vessels after the subcutaneous introduction of free silicone gel. Higher levels were found in afferent versus efferent lymph. This implies that migration of silicone gel does not occur soon after the exposure of a subcutaneous space to free silicone gel, or that the migration of silicone gel may occur by a cellular mechanism that can bypass the lymphatic vessels.

Role of the support material on laser desorption/ionization mass spectra

2008 ◽  
Vol 22 (7) ◽  
pp. 925-929 ◽  
Author(s):  
A. Gruszecka ◽  
M. Szymanska-Chargot ◽  
A. Smolira ◽  
J. Cytawa ◽  
L. Michalak
Keyword(s):  
Mass Spectra ◽  
Laser Desorption ◽  
Ionization Mass ◽  
Support Material ◽  
Laser Desorption Ionization ◽  
Desorption Ionization

Abiotic formation of RNA-like oligomers by montmorillonite catalysis: part II

2008 ◽  
Vol 7 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Gözen Ertem ◽  
Ann M. Snellinger-O'Brien ◽  
M. C. Ertem ◽  
D. A. Rogoff ◽  
Jason P. Dworkin ◽  
...  
Keyword(s):  
High Performance ◽  
Aqueous Electrolyte ◽  
Laser Desorption ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Phosphodiester Bonds ◽  
Ionization Mass Spectroscopy ◽  
Rna Fragments ◽  
Catalytic Role

AbstractThis work is an extension of our previous studies carried out to investigate the possible catalytic role of minerals in the abiotic synthesis of biologically important molecules. In the presence of montmorillonite, a member of the phyllosilicate group minerals that are abundant on Earth and identified on Mars, activated RNA monomers, namely 5′-phosphorimidazolides of nucleosides (ImpNs), undergo condensation reactions in aqueous electrolyte solution producing oligomers with similar structures to short RNA fragments. Analysis of the linear trimer isomers formed in the reaction of a mixture of activated adenosine and cytidine monomers (ImpA and ImpC, respectively) employing high-performance liquid chromatography, selective enzymatic hydrolysis and matrix-assisted laser desorption/ionization mass spectroscopy molecular weight measurements demonstrate that montmorillonite catalysis facilitates the formation of hetero-isomers containing 56% A- and 44% C-monomer incorporated in their structure. The results also show that 56% of the monomer units are linked together by RNA-like 3′, 5′-phosphodiester bonds. These results follow the same trend observed in our most recent work studying the reaction of activated adenosine and uridine monomers, and support Bernal's hypothesis proposing the possible catalytic role of minerals in the abiotic processes in the course of chemical evolution.

Role of Electrons in Laser Desorption/Ionization Mass Spectrometry

2003 ◽  
Vol 75 (22) ◽  
pp. 6063-6067 ◽  
Author(s):  
Vladimir E. Frankevich ◽  
Juan Zhang ◽  
Sebastian D. Friess ◽  
Maxim Dashtiev ◽  
Renato Zenobi
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Desorption Ionization
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