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Yang MY, Lee E, Park CS, Nam YS. Molecular Dynamics Investigation into CerENP's Effect on the Lipid Matrix of Stratum Corneum. J Phys Chem B 2024; 128:5378-5386. [PMID: 38805566 DOI: 10.1021/acs.jpcb.4c00053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
The extracellular lipid matrix in the stratum corneum (SC) plays a critical role in skin barrier functionality, comprising three primary components: ceramides, cholesterol, and free fatty acids. The diverse ceramides, differentiated by molecular structures such as hydroxylations and varying chain lengths, are essential for the lipid matrix's structural integrity. Recently, a new subclass of ceramide, 1-O-acylceramide NP (CerENP), has been identified; however, its precise role in the lipid matrix of the SC is still elusive. Herein, we investigate the role of CerENP on the structure and permeability of the SC using molecular dynamics simulations. Our findings indicate that CerENP contributes to a compact lipid matrix in the lateral dimension of our SC model with a repeat distance of about 13 nm. Additionally, ethanol permeability assessments show that CerENP effectively reduces molecular penetration through the lipid matrix. This study provides an insight into the role of a new subclass of ceramide in the SC, enhancing our understanding of skin structure and the mechanisms behind barrier dysfunction in skin diseases.
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Affiliation(s)
- Moon Young Yang
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, California 91125, United States
| | - Eunok Lee
- LCS Biotech Co. Ltd., 11-2, Deokseongsandan 2-ro 50, Idong-eup, Cheoin-gu, Yongin-si 17130, Gyeonggi-do, Republic of Korea
| | - Chang Seo Park
- LCS Biotech Co. Ltd., 11-2, Deokseongsandan 2-ro 50, Idong-eup, Cheoin-gu, Yongin-si 17130, Gyeonggi-do, Republic of Korea
| | - Yoon Sung Nam
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
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2
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Zhong F, Wang F, Yang H. Composition and structure analysis of different depths in the stratum corneum using confocal Raman microscopy combined with two-dimensional correlation spectroscopy. Talanta 2024; 270:125559. [PMID: 38141465 DOI: 10.1016/j.talanta.2023.125559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/09/2023] [Accepted: 12/13/2023] [Indexed: 12/25/2023]
Abstract
The chemical composition and structure of the stratum corneum (SC) play a crucial role in the skin barrier function. Therefore, accurately determining the SC thickness and studying the changes in lipid and keratin structure and distribution within it are key aspects of skin barrier research. Currently, there are limited analytical tools and data analysis methods available for real-time and online studies of SC composition and structural changes. In this study, we focus on depth as a perturbation and employ confocal Raman microscopy combined with moving-window two-dimensional correlation spectroscopy (MW2D) technique to investigate the SC thickness. Additionally, we employ confocal Raman microscopy combined with perturbation-correlation moving-window two-dimensional correlation spectroscopy (PCMW2D) to precisely characterize the stratification of the SC. Furthermore, the two-dimensional correlation spectroscopy (2DCOS) method is utilized to examine the content of various conformations in the keratin secondary structure within the SC, as well as the subtle interrelationships between lipid and keratin structures.
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Affiliation(s)
- Feng Zhong
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Municipal Education Committee Key Laboratory of Molecular Imaging Probes and Sensors, and Department of Chemistry, Shanghai Normal University, Shanghai, 200234, PR China
| | - Feng Wang
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Municipal Education Committee Key Laboratory of Molecular Imaging Probes and Sensors, and Department of Chemistry, Shanghai Normal University, Shanghai, 200234, PR China.
| | - Haifeng Yang
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Municipal Education Committee Key Laboratory of Molecular Imaging Probes and Sensors, and Department of Chemistry, Shanghai Normal University, Shanghai, 200234, PR China.
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3
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Dao L, Dong Y, Song L, Sa C. The Fate of 1,8-cineole as a Chemical Penetrant: A Review. Curr Drug Deliv 2024; 21:697-708. [PMID: 37165499 DOI: 10.2174/1567201820666230509101602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 02/22/2023] [Accepted: 03/13/2023] [Indexed: 05/12/2023]
Abstract
The stratum corneum continues to pose the biggest obstacle to transdermal drug delivery. Chemical penetrant, the first generation of transdermal drug delivery system, offers a lot of potential. In order to fully examine the permeation mechanism of 1,8-cineole, a natural monoterpene, this review summarizes the effects of permeation-enhancing medications on drugs that are lipophilic and hydrophilic as well as the toxicity of this substance on the skin and other tissues. For lower lipophilic drugs, 1,8-cineole appears to have a stronger osmotic-enhancing impact. An efficient and secure tactic would be to combine enhancers and dose forms. 1,8-cineole is anticipated to be further developed in the transdermal drug delivery system and even become a candidate drug for brain transport due to its permeability and low toxicity.
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Affiliation(s)
- Ligema Dao
- School of Mongolian Medicine, Inner Mongolian Medical University, Hohhot, China
| | - Yu Dong
- School of Pharmacy, Inner Mongolian Medical University, Hohhot, China
| | - Lin Song
- School of Mongolian Medicine, Inner Mongolian Medical University, Hohhot, China
| | - Chula Sa
- School of Mongolian Medicine, Inner Mongolian Medical University, Hohhot, China
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4
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Porto Ferreira VT, Silva GC, Martin AA, Maia Campos PMBG. Topical dexpanthenol effects on physiological parameters of the stratum corneum by Confocal Raman Microspectroscopy. Skin Res Technol 2023; 29:e13317. [PMID: 37753694 PMCID: PMC10504581 DOI: 10.1111/srt.13317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 03/23/2023] [Indexed: 09/28/2023]
Abstract
BACKGROUND Topical use of dexpanthenol presents well-established moisturizing properties and maintenance and repair of the skin barrier function, however, its exact action mechanisms are not completely elucidated. In this context, Confocal Raman Microspectroscopy is an optical method that enables non-invasive and non-destructive in vivo analysis with the sensitive acquisition of molecular changes in different skin layers. Herein, the aim was to evaluate the effects of topical dexpanthenol on the components and physiological parameters of the stratum corneum (SC). MATERIALS AND METHODS Ten healthy female subjects underwent skin evaluation by means of a Confocal Raman Spectrometer Skin Analyzer 3510. Spectral data were obtained from the skin of the anterior forearm region, before and 2 h after applying a cosmetic formulation containing or not containing 5% dexpanthenol. RESULTS Semiquantitative analysis of the natural moisturizing factor showed a significant decrease in content after 2 h of topical dexpanthenol application, while the analysis of the lamellar organization of intercellular lipids and the secondary structure of keratin showed a significant increase in hexagonal organization of lipids at the first half of the SC and a significant increase in β-pleated sheet conformation of keratin. CONCLUSION Effects of topical dexpanthenol on SC suggest a contribution in increasing fluidity of both lipidic and protein components of the SC and are compatible with dexpanthenol activity in maintaining adequate physiological conditions and preventing transepidermal water loss. This study also contributes to the elucidation of action mechanisms and other concurrent biochemical processes.
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Affiliation(s)
- Vitoria Tonini Porto Ferreira
- Department of Phmarmaceutical Sciences, School of Pharmaceutical Sciences of Riberão PretoUniversity of São PauloSão PauloBrazil
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5
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Badhe Y, Schmitt T, Gupta R, Rai B, Neubert RH. Investigating the nanostructure of a CER[NP]/CER[AP]-based stratum corneum lipid matrix model: A combined neutron diffraction & molecular dynamics simulations approach. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - BIOMEMBRANES 2022; 1864:184007. [PMID: 35863424 DOI: 10.1016/j.bbamem.2022.184007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 06/29/2022] [Accepted: 07/12/2022] [Indexed: 10/17/2022]
Abstract
The human skin provides a physiochemical and biological protective barrier due to the unique structure of its outermost layer known as the Stratum corneum. This layer consists of corneocytes and a multi-lamellar lipid matrix forming a composite, which is a major determining factor for the barrier function of the Stratum corneum. A substantiated understanding of this barrier is necessary, as controlled breaching or modulation of the same is also essential for various health and personal care applications such as topical drug delivery and cosmetics to a name few. In this study, we discuss the state-of-the-art of neutron diffraction techniques, using specifically deuterated lipids, combined with the information obtained from molecular models using molecular dynamics simulations, to understand the structure and barrier function of the Stratum corneum lipid matrix. As an example, the effect of ceramide concentration on a lipid lamella system consisting of CER[NP]/CER[AP]/Cholesterol/free fatty acid (deprotonated) is studied. This study demonstrates the usefulness of the combined approach of neutron diffraction and molecular dynamics simulations for effective analysis of the model systems created for the Stratum corneum lipid matrix. The optimization of force fields by comparison with experimental data is furthermore an important step in the direction of providing a predictive quality.
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Shamaprasad P, Frame CO, Moore TC, Yang A, Iacovella CR, Bouwstra JA, Bunge AL, McCabe C. Using molecular simulation to understand the skin barrier. Prog Lipid Res 2022; 88:101184. [PMID: 35988796 PMCID: PMC10116345 DOI: 10.1016/j.plipres.2022.101184] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 11/15/2022]
Abstract
Skin's effectiveness as a barrier to permeation of water and other chemicals rests almost entirely in the outermost layer of the epidermis, the stratum corneum (SC), which consists of layers of corneocytes surrounded by highly organized lipid lamellae. As the only continuous path through the SC, transdermal permeation necessarily involves diffusion through these lipid layers. The role of the SC as a protective barrier is supported by its exceptional lipid composition consisting of ceramides (CERs), cholesterol (CHOL), and free fatty acids (FFAs) and the complete absence of phospholipids, which are present in most biological membranes. Molecular simulation, which provides molecular level detail of lipid configurations that can be connected with barrier function, has become a popular tool for studying SC lipid systems. We review this ever-increasing body of literature with the goals of (1) enabling the experimental skin community to understand, interpret and use the information generated from the simulations, (2) providing simulation experts with a solid background in the chemistry of SC lipids including the composition, structure and organization, and barrier function, and (3) presenting a state of the art picture of the field of SC lipid simulations, highlighting the difficulties and best practices for studying these systems, to encourage the generation of robust reproducible studies in the future. This review describes molecular simulation methodology and then critically examines results derived from simulations using atomistic and then coarse-grained models.
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Affiliation(s)
- Parashara Shamaprasad
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America
| | - Chloe O Frame
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America
| | - Timothy C Moore
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America
| | - Alexander Yang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America
| | - Christopher R Iacovella
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America
| | - Joke A Bouwstra
- Division of BioTherapeutics, LACDR, Leiden University, 2333 CC Leiden, the Netherlands
| | - Annette L Bunge
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, United States of America
| | - Clare McCabe
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604, United States of America; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, TN 37235-1604, United States of America; School of Engineering and Physical Science, Heriot-Watt University, Edinburgh, United Kingdom.
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7
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Poljšak N, Kočevar Glavač N. Vegetable Butters and Oils as Therapeutically and Cosmetically Active Ingredients for Dermal Use: A Review of Clinical Studies. Front Pharmacol 2022; 13:868461. [PMID: 35548366 PMCID: PMC9083541 DOI: 10.3389/fphar.2022.868461] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 03/21/2022] [Indexed: 11/13/2022] Open
Abstract
While the chemical composition of vegetable butters and oils has been studied in detail, there is limited knowledge about their mechanisms of action after application on the skin. To understand their dermal effects better, 27 clinical studies evaluating 17 vegetable oils (almond, argan, avocado, borage, coconut, evening primrose, kukui, marula, mustard, neem, olive, rapeseed, sacha inchi, safflower, shea butter, soybean and sunflower oils) were reviewed in this research. The reviewed studies focused on non-affected skin, infant skin, psoriasis, xerosis, UVB-induced erythema, atopic dermatitis, molluscum contagiosum, tungiasis, scars, striae and striae gravidarum. We conclude that in inflammation-affected skin, vegetable oils with a high content of oleic acid, together with the lack of or a low linoleic acid content, may cause additional structural damage of the stratum corneum, while oils high in linoleic acid and saturated fatty acids may express positive effects. Non-affected skin, in contrast, may not react negatively to oils high in oleic acid. However, the frequency and duration of an oil's use must be considered an important factor that may accelerate or enhance the negative effects on the skin's structural integrity.
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Affiliation(s)
- Nina Poljšak
- Department of Pharmaceutical Biology, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Nina Kočevar Glavač
- Department of Pharmaceutical Biology, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
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8
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Róg T, Girych M, Bunker A. Mechanistic Understanding from Molecular Dynamics in Pharmaceutical Research 2: Lipid Membrane in Drug Design. Pharmaceuticals (Basel) 2021; 14:1062. [PMID: 34681286 PMCID: PMC8537670 DOI: 10.3390/ph14101062] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 11/17/2022] Open
Abstract
We review the use of molecular dynamics (MD) simulation as a drug design tool in the context of the role that the lipid membrane can play in drug action, i.e., the interaction between candidate drug molecules and lipid membranes. In the standard "lock and key" paradigm, only the interaction between the drug and a specific active site of a specific protein is considered; the environment in which the drug acts is, from a biophysical perspective, far more complex than this. The possible mechanisms though which a drug can be designed to tinker with physiological processes are significantly broader than merely fitting to a single active site of a single protein. In this paper, we focus on the role of the lipid membrane, arguably the most important element outside the proteins themselves, as a case study. We discuss work that has been carried out, using MD simulation, concerning the transfection of drugs through membranes that act as biological barriers in the path of the drugs, the behavior of drug molecules within membranes, how their collective behavior can affect the structure and properties of the membrane and, finally, the role lipid membranes, to which the vast majority of drug target proteins are associated, can play in mediating the interaction between drug and target protein. This review paper is the second in a two-part series covering MD simulation as a tool in pharmaceutical research; both are designed as pedagogical review papers aimed at both pharmaceutical scientists interested in exploring how the tool of MD simulation can be applied to their research and computational scientists interested in exploring the possibility of a pharmaceutical context for their research.
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Affiliation(s)
- Tomasz Róg
- Department of Physics, University of Helsinki, 00014 Helsinki, Finland;
| | - Mykhailo Girych
- Department of Physics, University of Helsinki, 00014 Helsinki, Finland;
| | - Alex Bunker
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 Helsinki, Finland;
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9
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Mohd Nordin UU, Ahmad N, Salim N, Mohd Yusof NS. Lipid-based nanoparticles for psoriasis treatment: a review on conventional treatments, recent works, and future prospects. RSC Adv 2021; 11:29080-29101. [PMID: 35478537 PMCID: PMC9038133 DOI: 10.1039/d1ra06087b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 08/19/2021] [Indexed: 12/19/2022] Open
Abstract
Psoriasis is a lingering inflammatory skin disease that attacks the immune system. The abnormal interactions between T cells, immune cells, and inflammatory cytokines causing the epidermal thickening. International guidelines have recommended topical treatments for mild to moderate psoriasis whilst systemic and phototherapy treatments for moderate to severe psoriasis. However, current therapeutic approaches have a wider extent to treat moderate to severe type of psoriasis especially since the emergence of diverse biologic agents. In the meantime, topical delivery of conventional treatments has prompted many unsatisfactory effects to penetrate through the skin (stratum corneum). By understanding the physiology of stratum corneum barrier functions, scientists have developed different types of lipid-based nanoparticles like solid lipid nanoparticles, nanostructured lipid carriers, nanovesicles, and nanoemulsions. These novel drug delivery systems help the poorly solubilised active pharmaceutical ingredient reaches the targeted site seamlessly because of the bioavailability feature of the nanosized molecules. Lipid-based nanoparticles for psoriasis treatments create a paradigm for topical drug delivery due to their lipids' amphiphilic feature to efficiently encapsulate both lipophilic and hydrophilic drugs. This review highlights different types of lipid-based nanoparticles and their recent works of nano formulated psoriasis treatments. The encapsulation of psoriasis drugs through lipid nanocarriers unfold numerous research opportunities in pharmaceutical applications but also draw challenges for the future development of nano drugs.
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Affiliation(s)
- Ummu Umaimah Mohd Nordin
- Department of Chemistry, Faculty of Science, University of Malaya 50603 Kuala Lumpur Malaysia +603-79674193 +603-79674008
| | - Noraini Ahmad
- Department of Chemistry, Faculty of Science, University of Malaya 50603 Kuala Lumpur Malaysia +603-79674193 +603-79674008
| | - Norazlinaliza Salim
- Integrated Chemical Biophysics Research, Faculty of Science, Universiti Putra Malaysia 43400 UPM Serdang Selangor Malaysia
| | - Nor Saadah Mohd Yusof
- Department of Chemistry, Faculty of Science, University of Malaya 50603 Kuala Lumpur Malaysia +603-79674193 +603-79674008
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10
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Schmitt T, Neubert RHH. State of the Art in Stratum Corneum Research. Part II: Hypothetical Stratum Corneum Lipid Matrix Models. Skin Pharmacol Physiol 2020; 33:213-230. [PMID: 32683377 DOI: 10.1159/000509019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/05/2020] [Indexed: 12/31/2022]
Abstract
This review is the second part of a series which presents the state of the art in stratum corneum (SC) lipid matrix (LM) research in depth. In this part, the various hypothetical models which were developed to describe the structure and function of the SC LM as the skin's barrier will be discussed. New as well as a cumulative assortment of older results which change the view on the different models are considered to conclude how well the different models are holding up today. As a final conclusion, a model, factoring in as much of the known data as possible, is concluded, unifying the varying different models into one which can be developed further, as new results are found in the future. So far, the model is described with a single crystalline or gel-like phase with a certain amount of nanocrystallites of concentrated ceramides (CERs) and free fatty acids and more fluid nanodomains caused by a fluidizing effect of the cholesterol. These domains are dynamically resolved and reformed and do not impair the barrier function. The chain conformation is not completely clear yet; however, an equilibrium of fully extended and hairpin-folded CERs with ratios depending on the properties of each individual CER species is proposed as most likely. An overlapping middle layer as described for the tri-layer model in part I of this series would be present for both conformations. The macroscopic broad-narrow-broad layering, observed in electron micrographs, is explained by an external templating by the lipid envelope, and an internal templating by short and long lipid chains each preferentially show a homophilic association, forming thicker and thinner bilayers, respectively. The degree of influence of the very long ω-hydroxy-CERs is discussed as well.
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Affiliation(s)
- Thomas Schmitt
- Department I, Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Reinhard H H Neubert
- Institute of Applied Dermatopharmacy at the Martin Luther University Halle-Wittenberg (IADP), Halle/Saale, Germany, .,Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany,
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11
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Badhe Y, Gupta R, Rai B. Development and application of coarse-grained MARTINI model of skin lipid ceramide [AP]. J Mol Model 2020; 26:182. [PMID: 32583227 DOI: 10.1007/s00894-020-04435-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 06/02/2020] [Indexed: 01/10/2023]
Abstract
Stratum corneum (SC), the outermost layer of the skin, contains large variety of lipids, endowing them with the amphiphilic properties, needed to fulfil their key role in skin's barrier function. The individual role of lipid types in the barrier function is difficult to understand due to the immense heterogeneity and complexity of the lipid's organization within the SC. The lipid organization is being explored using both computational (molecular dynamics simulations) and experimental (neutron diffraction) techniques. Even though atomistic simulations provide unprecedented atomic level details, the major limitation is time and length scale that can be achieved with decent computational facility. Alternatively, coarse-grain (CG) models are currently being used to capture physics at bigger time and length scale without losing essential underlined structural information. In this study, a CG model of α-hydroxy phytosphingosines (CER[AP]) is developed based on philosophy of MARTINI force field. At first, the model is validated with various atomistic simulations and available experimental data. Later on, the model's compatibility with other major skin lipids, cholesterol, and free fatty acid (palmitic acid) is checked by simulating a mixture of lipid multilayer in presence and absence of water. The developed model of CER[AP] is able to predict key structural properties within the acceptable error limits. The phenomena of ceramide conformation transformation, cholesterol flip-flop, and specificity of lipid arrangement within the multilayered systems is observed during the simulation. This signifies the importance of model in capturing higher order structural transformations.
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Affiliation(s)
- Yogesh Badhe
- Physical Science Research Area, TCS Research, Tata Research Development and Design Centre, Tata Consultancy Services, 54B, Hadapsar Industrial Estate, Pune, 411013, India
| | - Rakesh Gupta
- Physical Science Research Area, TCS Research, Tata Research Development and Design Centre, Tata Consultancy Services, 54B, Hadapsar Industrial Estate, Pune, 411013, India.
| | - Beena Rai
- Physical Science Research Area, TCS Research, Tata Research Development and Design Centre, Tata Consultancy Services, 54B, Hadapsar Industrial Estate, Pune, 411013, India
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12
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Gajula K, Gupta R, Rai B. Multiscale Modeling of Skin Electroporation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6651-6660. [PMID: 32475118 DOI: 10.1021/acs.langmuir.0c00500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Human skin, the largest external organ of the body, provides a selective barrier to therapeutics applied topically. The molecules having specific chemical and physical properties can only penetrate the deeper layer of the skin. However, the lag time for reaching a steady state in the deeper layer is generally of the order of hours. In order to deliver higher-molecular-weight, charged, and hydrophilic therapeutics in the deeper layer, the skin barrier must be breached. Electroporation is one of the methods used to breach the skin barrier for enhancement of drug permeation and reduction of lag time. However, the underlying mechanism responsible for the enhancement of drug permeation is not well understood. In this study, a multiscale model of skin electroporation is developed by connecting molecular phenomena to a macroscopic model. At the atomic scale, molecular dynamics simulations of the lipid matrix of the human stratum corneum (SC) were performed under the influence of an external electric field. The pores get formed during the electroporation process and the transport properties (diffusivity) of drug molecules are computed. The diffusion coefficient obtained during electroporation was found to be higher than passive diffusion. However, this alone could not explain the multifold increase in the drug flux on application of an electric field as observed in the experiments. Hence, a finite element method (FEM) model of the skin SC is also developed. The release of fentanyl through this model is compared with the available experimental results. Both experimental and simulated results of pore formation on application of an electric field and many folds' increase in drug flux are comparable. Once validated, the framework was used for the design of skin electroporation experiments (in silico) by changing the electric pulse parameters such as voltage, pulse duration, and number of pulses. This multiscale modeling framework provides valuable insight at the molecular and macroscopic levels to design the electroporation experiments. The framework can be utilized as a design tool for skin electroporation applications.
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Affiliation(s)
- Kishore Gajula
- Physical Sciences Research Area, Tata Research Development and Design Centre, Tata Consultancy Services, 54 B, Hadapsar Industrial Estate, Pune 411013, India
| | - Rakesh Gupta
- Physical Sciences Research Area, Tata Research Development and Design Centre, Tata Consultancy Services, 54 B, Hadapsar Industrial Estate, Pune 411013, India
| | - Beena Rai
- Physical Sciences Research Area, Tata Research Development and Design Centre, Tata Consultancy Services, 54 B, Hadapsar Industrial Estate, Pune 411013, India
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13
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Gupta R, Badhe Y, Rai B, Mitragotri S. Molecular mechanism of the skin permeation enhancing effect of ethanol: a molecular dynamics study. RSC Adv 2020; 10:12234-12248. [PMID: 35497613 PMCID: PMC9050718 DOI: 10.1039/d0ra01692f] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 03/16/2020] [Indexed: 02/01/2023] Open
Abstract
Ethanol is widely used in various pharmaceutical and cosmetic formulations in order to enhance skin penetration of active ingredients. While it is well known that ethanol partitions into the skin and enhances the permeation of both polar and nonpolar molecules, the exact mechanisms by which it enhances skin permeability are not fully understood. Several mechanisms have been proposed including lipid extraction from the stratum corneum (SC), fluidisation of SC lipid bilayer, alteration of SC protein conformation and enhancement of the drug solubility in the SC lipids. In this study, we performed molecular dynamics (MD) simulations of SC lipid bilayers comprised of an equimolar mixture of ceramides, cholesterol and free fatty acid in the presence of aqueous mixtures of ethanol. Various unrestrained MD simulations were performed in the presence of aqueous ethanol solution at molar ratios (x) ranging from x = 0 to x = 1. It was found that ethanol enhances bilayer permeability by dual actions (a) extraction of the skin lipids and (b) enhancing the mobility of lipid chains. Ethanol's permeation enhancing effect arises from its superior ability to form hydrogen bonds with headgroup atoms of skin lipids. Further, the free energy of extraction of ceramides (CER) and fatty acids (FFA) from the lipid bilayer was studied using umbrella sampling simulations. The free energy of extraction of CER was found to be much higher compared to FFA for all ethanol concentrations which shows that CER are difficult to extract as compared to FFA. Finally, the permeation of benzoic acid drug molecules through the skin lipid bilayer is shown in presence of ethanol molecules. It was found that ethanol selectively targets the FFA of the skin lipid bilayer and extracts it out of the lipid bilayer within few microseconds. Further, ethanol penetrates inside the lipid layer and creates the channels from which drug molecules can easily cross the lipid layer. Our observations (both in unrestrained and umbrella sampling simulations) are consistent with the experimental findings reported in the literature. The simulation methodology could be used for design and testing of permeation enhancers (acting on skin SC lipid lamella) for topical and transdermal drug delivery applications. Concentration dependent action of mechanism of ethanol on skin SC lipid barrier.![]()
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Affiliation(s)
- Rakesh Gupta
- Physical Science Research Area
- Tata Research Development and Design Centre
- TCS Research
- Tata Consultancy Services
- Pune – 411013
| | - Yogesh Badhe
- Physical Science Research Area
- Tata Research Development and Design Centre
- TCS Research
- Tata Consultancy Services
- Pune – 411013
| | - Beena Rai
- Physical Science Research Area
- Tata Research Development and Design Centre
- TCS Research
- Tata Consultancy Services
- Pune – 411013
| | - Samir Mitragotri
- School of Engineering and Applied Sciences
- Wyss Institute
- Harvard University
- USA
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