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Zhang Q, Flach CR, Mendelsohn R, Page L, Whitson S, Boncheva Bettex M. Visualization of Epidermal Reservoir Formation from Topical Diclofenac Gels by Raman Spectroscopy. J Pain Res 2020; 13:1621-1627. [PMID: 32753939 PMCID: PMC7342390 DOI: 10.2147/jpr.s253069] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/09/2020] [Indexed: 11/23/2022] Open
Abstract
Purpose This work investigated whether topical pain relief diclofenac gels can form a diclofenac reservoir in the epidermal and dermal layers of human skin. Methods Excised human skin samples were treated with three topical diclofenac gels ex vivo and examined using Raman microscopy of transversally microtomed sections. The relative diclofenac concentration in the skin layers was calculated as the ratio of the integrated areas of bands characteristic of diclofenac (~445 cm−1) and skin (Amide I). A customized masking algorithm ensured that only diclofenac-specific signal was mapped in the resulting Raman images. Results A heterogenous spatial distribution of diclofenac was clearly visible in both the epidermis and the dermis in all samples, with a markedly higher diclofenac relative content and number of pixels above the detection limit in the epidermis compared to the dermis. Conclusion The Raman images evidenced that the studied topical gels deliver diclofenac through the stratum corneum skin barrier and form a drug depot localized in the epidermis. The data are in line with earlier clinical findings that this depot acts like a true reservoir and enables sustained drug release.
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Affiliation(s)
- Qihong Zhang
- Department of Chemistry, Rutgers University, Newark, NJ 07102, USA
| | - Carol R Flach
- Department of Chemistry, Rutgers University, Newark, NJ 07102, USA
| | | | - Leanne Page
- Charles River Laboratories Edinburgh Ltd., Tranent, East Lothian, UK
| | - Susan Whitson
- Charles River Laboratories Edinburgh Ltd., Tranent, East Lothian, UK
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2
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Pyatski Y, Flach CR, Mendelsohn R. FT-IR investigation of Terbinafine interaction with stratum corneum constituents. Biochim Biophys Acta Biomembr 2020; 1862:183335. [PMID: 32376224 DOI: 10.1016/j.bbamem.2020.183335] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/13/2020] [Accepted: 04/28/2020] [Indexed: 11/16/2022]
Abstract
Terbinafine (Tbf) is a well-established anti-fungal agent used for management of a variety of dermal conditions including ringworm and athlete's foot. Both the biochemical mechanism of Tbf fungicidal action (based on squalene epoxidase inhibition) and the target region for Tbf in vivo (the stratum corneum (SC)) are well determined. However, the biochemical and pharmacokinetic approaches used to evaluate Tbf biochemistry provide no biophysical information about molecular level physical changes in the SC upon Tbf binding. Such information is necessary for improved drug and formulation design. IR spectroscopic methods were used to evaluate the effects of Tbf on keratin structure in environments commonly used in pharmaceutics to mimic those in vivo. The Amide I and II spectral regions (1500-1700 cm-1) provided an effective means to monitor keratin secondary structure changes, while a Tbf spectral feature near 775 cm-1 provides a measure of relative Tbf levels in skin. Interaction of Tbf with the SC induced substantial β-sheet formation in the keratin, an effect which was partially reversed both by ethanol washing and by exposure to high relative humidity. The irreversibility suggests the presence of a Tbf reservoir (consistent with kinetic studies), permitting the drug to be released in a controlled manner into the surrounding tissue.
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Affiliation(s)
- Yelena Pyatski
- Department of Chemistry, Newark College of Arts and Sciences, Rutgers University, Newark, NJ 07102, USA
| | - Carol R Flach
- Department of Chemistry, Newark College of Arts and Sciences, Rutgers University, Newark, NJ 07102, USA.
| | - Richard Mendelsohn
- Department of Chemistry, Newark College of Arts and Sciences, Rutgers University, Newark, NJ 07102, USA
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3
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Wang H, Zhang Q, Mao G, Conroy O, Pyatski Y, Fevola MJ, Cula GO, Maitra P, Mendelsohn R, Flach CR. Novel confocal Raman microscopy method to investigate hydration mechanisms in human skin. Skin Res Technol 2019; 25:653-661. [PMID: 30932226 DOI: 10.1111/srt.12698] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 02/14/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Skin hydration is essential for maintaining stratum corneum (SC) flexibility and facilitating maturation events. Moisturizers contain multiple ingredients to maintain and improve skin hydration although a complete understanding of hydration mechanisms is lacking. The ability to differentiate the source of the hydration (water from the environment or deeper skin regions) upon application of product will aid in designing more efficacious formulations. MATERIALS AND METHODS Novel confocal Raman microscopy (CRM) experiments allow us to investigate mechanisms and levels of hydration in the SC. Using deuterium oxide (D2 O) as a probe permits the differentiation of endogenous water (H2 O) from exogenous D2 O. Following topical application of D2 O, we first compare in vivo skin depth profiles with those obtained using ex vivo skin. Additional ex vivo experiments are conducted to quantify the kinetics of D2 O diffusion in the epidermis by introducing D2 O under the dermis. RESULTS Relative D2 O depth profiles from in vivo and ex vivo measurements compare well considering procedural and instrumental differences. Additional in vivo experiments where D2 O was applied following topical glycerin application increased the longevity of D2 O in the SC. Reproducible rates of D2 O diffusion as a function of depth have been established for experiments where D2 O is introduced under ex vivo skin. CONCLUSION Unique information regarding hydration mechanisms are obtained from CRM experiments using D2 O as a probe. The source and relative rates of hydration can be delineated using ex vivo skin with D2 O underneath. One can envision comparing these depth-dependent rates in the presence and absence of topically applied hydrating agents to obtain mechanistic information.
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Affiliation(s)
- Hequn Wang
- Johnson and Johnson Consumer Companies, Inc., Skillman, New Jersey
| | - Qihong Zhang
- Department of Chemistry, Rutgers University, Newark, New Jersey
| | - Guangru Mao
- Johnson and Johnson Consumer Companies, Inc., Skillman, New Jersey
| | - Oscar Conroy
- Johnson and Johnson Consumer Companies, Inc., Skillman, New Jersey
| | - Yelena Pyatski
- Department of Chemistry, Rutgers University, Newark, New Jersey
| | - Michael J Fevola
- Johnson and Johnson Consumer Companies, Inc., Skillman, New Jersey
| | | | | | | | - Carol R Flach
- Department of Chemistry, Rutgers University, Newark, New Jersey
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4
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Bianchini JM, Zhang Q, Hanna G, Flach CR, Wang H, Southall MD, Mendelsohn R, Randhawa M. <p>A unique gel matrix moisturizer delivers deep hydration resulting in significant clinical improvement in radiance and texture</p>. Clin Cosmet Investig Dermatol 2019; 12:229-239. [PMID: 31114284 PMCID: PMC6489629 DOI: 10.2147/ccid.s196110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/20/2019] [Indexed: 11/23/2022]
Abstract
Introduction: As skin ages, it loses its ability to retain moisture and becomes rough and dry. This results in a clinically dull appearance with a loss of radiance, firmness, and suppleness. Symptoms can be improved with use of a moisturizer that builds and maintains skin hydration over time; however, most moisturizers that occlude the skin surface are perceived as heavy and greasy and are not consumer preferred. Methods: A unique, consumer-preferred gel matrix formula was developed by combining liquid crystal structures, which mimic skin barrier lipid assembly, with specific emulsifiers that deliver water deep into skin. Ex vivo studies were conducted to investigate the superior hydrating effects of the gel matrix formula. Confocal Raman microscopy studies assessed the spatial distribution of water in ex vivo skin after application of the gel matrix formula. To determine the effects of the gel matrix formula on dry facial skin, a 12-week clinical study was conducted with subjects with self-perceived skin dryness and dullness. Results: The formulation significantly increased the relative water content throughout epidermal regions, which was not observed with the application of a competitive gel formula. Instrumental measurements assessed improvements in skin surface moisturization and barrier function. Clinical grading showed significant improvements in hydration-related endpoints including radiance, clarity, and texture. Subject self-agree assessment demonstrated that subjects observed improvements in the appearance of their facial skin. Conclusion: These studies demonstrated that the gel matrix formula increased skin water content in deeper layers, and resulted in significant clinical improvements in hydration, barrier function, and clinical appearance of radiance.
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Affiliation(s)
| | - Qihong Zhang
- Department of Chemistry, Rutgers University, Newark, NJ, USA
| | - Gabriel Hanna
- Department of Chemistry, Rutgers University, Newark, NJ, USA
| | - Carol R Flach
- Department of Chemistry, Rutgers University, Newark, NJ, USA
| | - Hequn Wang
- Johnson and Johnson Consumer Companies, Inc., Skillman, NJ, USA
| | | | | | - Manpreet Randhawa
- Johnson and Johnson Consumer Companies, Inc., Skillman, NJ, USA
- Correspondence: Manpreet RandhawaJohnson & Johnson Consumer Companies, Inc., 199 Grandview Road, Skillman, NJ08558, USAPhone +1 908 904 3062Fax +1 908 874 1209Email
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5
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Li WH, Zhang Q, Flach CR, Mendelsohn R, Southall MD, Parsa R. In vitro modeling of unsaturated free fatty acid-mediated tissue impairments seen in acne lesions. Arch Dermatol Res 2017; 309:529-540. [DOI: 10.1007/s00403-017-1747-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 01/24/2017] [Accepted: 05/23/2017] [Indexed: 01/04/2023]
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6
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Kaya S, Basta-Pljakic J, Seref-Ferlengez Z, Majeska RJ, Cardoso L, Bromage T, Zhang Q, Flach CR, Mendelsohn R, Yakar S, Fritton SP, Schaffler MB. Lactation-Induced Changes in the Volume of Osteocyte Lacunar-Canalicular Space Alter Mechanical Properties in Cortical Bone Tissue. J Bone Miner Res 2017; 32:688-697. [PMID: 27859586 PMCID: PMC5395324 DOI: 10.1002/jbmr.3044] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/27/2016] [Accepted: 11/15/2016] [Indexed: 01/23/2023]
Abstract
Osteocytes can remove and remodel small amounts of their surrounding bone matrix through osteocytic osteolysis, which results in increased volume occupied by lacunar and canalicular space (LCS). It is well established that cortical bone stiffness and strength are strongly and inversely correlated with vascular porosity, but whether changes in LCS volume caused by osteocytic osteolysis are large enough to affect bone mechanical properties is not known. In the current studies we tested the hypotheses that (1) lactation and postlactation recovery in mice alter the elastic modulus of bone tissue, and (2) such local changes in mechanical properties are related predominantly to alterations in lacunar and canalicular volume rather than bone matrix composition. Mechanical testing was performed using microindentation to measure modulus in regions containing solely osteocytes and no vascular porosity. Lactation caused a significant (∼13%) reduction in bone tissue-level elastic modulus (p < 0.001). After 1 week postweaning (recovery), bone modulus levels returned to control levels and did not change further after 4 weeks of recovery. LCS porosity tracked inversely with changes in cortical bone modulus. Lacunar and canalicular void space increased 7% and 15% with lactation, respectively (p < 0.05), then returned to control levels at 1 week after weaning. Neither bone mineralization (assessed by high-resolution backscattered scanning electron microscopy) nor mineral/matrix ratio or crystallinity (assessed by Raman microspectroscopy) changed with lactation. Thus, changes in bone mechanical properties induced by lactation and recovery appear to depend predominantly on changes in osteocyte LCS dimensions. Moreover, this study demonstrates that tissue-level cortical bone mechanical properties are rapidly and reversibly modulated by osteocytes in response to physiological challenge. These data point to a hitherto unappreciated role for osteocytes in modulating and maintaining local bone mechanical properties. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Serra Kaya
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Jelena Basta-Pljakic
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | | | - Robert J Majeska
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Luis Cardoso
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Timothy Bromage
- Department of Biomaterials, New York University College of Dentistry, New York, NY, USA
| | - Qihong Zhang
- Department of Chemistry, Rutgers University, Newark, NJ, USA
| | - Carol R Flach
- Department of Chemistry, Rutgers University, Newark, NJ, USA
| | | | - Shoshana Yakar
- Department of Basic Science, New York University College of Dentistry, New York, NY, USA
| | - Susannah P Fritton
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Mitchell B Schaffler
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
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7
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Pyatski Y, Zhang Q, Mendelsohn R, Flach CR. Effects of permeation enhancers on flufenamic acid delivery in Ex vivo human skin by confocal Raman microscopy. Int J Pharm 2016; 505:319-28. [PMID: 27063850 DOI: 10.1016/j.ijpharm.2016.04.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/22/2016] [Accepted: 04/04/2016] [Indexed: 10/22/2022]
Abstract
For effective topical delivery, a drug must cross the stratum corneum (SC) barrier into viable tissue. The use of permeation enhancers is a widespread approach for barrier modification. In the current study, flufenamic acid (FluA), a non-steroidal anti-inflammatory drug, is a model agent for investigating the influence of hydrophobic versus hydrophilic enhancers. In separate experiments, FluA in octanol or propylene glycol/ethanol (75/25) is applied to the SC for varying times followed by confocal Raman microscopic mapping of drug and enhancer penetration and spatial distribution. Deuterated versions of the enhancers permit us to spectroscopically distinguish the exogenous chemicals from the endogenous SC lipids without affecting penetration parameters. The FluA pathway is tracked by the CC stretching mode at ∼1618cm(-1). Discrete, small inclusions of both enhancers are observed throughout the SC. High concentrations of FluA are co-localized with octanol domains which appear to provide a pathway to the viable epidermis for the drug. In contrast, FluA concentrates in the upper SC when using the hydrophilic agent and endogenous lipids appear unperturbed in regions outside the enhancer pockets. The ability to examine perturbations to endogenous ultrastructure and molecular structure in skin while tracking penetration pathways provides insight into delivery mechanisms.
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Affiliation(s)
- Yelena Pyatski
- Rutgers University, Department of Chemistry, 73 Warren Street, Newark, NJ 07102, United States
| | - Qihong Zhang
- Rutgers University, Department of Chemistry, 73 Warren Street, Newark, NJ 07102, United States
| | - Richard Mendelsohn
- Rutgers University, Department of Chemistry, 73 Warren Street, Newark, NJ 07102, United States
| | - Carol R Flach
- Rutgers University, Department of Chemistry, 73 Warren Street, Newark, NJ 07102, United States.
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8
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Patel MA, Luo F, Khoshi MR, Rabie E, Zhang Q, Flach CR, Mendelsohn R, Garfunkel E, Szostak M, He H. P-Doped Porous Carbon as Metal Free Catalysts for Selective Aerobic Oxidation with an Unexpected Mechanism. ACS Nano 2016; 10:2305-2315. [PMID: 26751165 DOI: 10.1021/acsnano.5b07054] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An extremely simple and rapid (seconds) approach is reported to directly synthesize gram quantities of P-doped graphitic porous carbon materials with controlled P bond configuration. For the first time, it is demonstrated that the P-doped carbon materials can be used as a selective metal free catalyst for aerobic oxidation reactions. The work function of P-doped carbon materials, its connectivity to the P bond configuration, and the correlation with its catalytic efficiency are studied and established. In direct contrast to N-doped graphene, the P-doped carbon materials with higher work function show high activity in catalytic aerobic oxidation. The selectivity trend for the electron donating and withdrawing properties of the functional groups attached to the aromatic ring of benzyl alcohols is also different from other metal free carbon based catalysts. A unique catalytic mechanism is demonstrated, which differs from both GO and N-doped graphene obtained by high temperature nitrification. The unique and unexpected catalytic pathway endows the P-doped materials with not only good catalytic efficiency but also recyclability. This, combined with a rapid, energy saving approach that permits fabrication on a large scale, suggests that the P-doped porous materials are promising materials for "green catalysis" due to their higher theoretical surface area, sustainability, environmental friendliness, and low cost.
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Affiliation(s)
- Mehulkumar A Patel
- Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States
| | - Feixiang Luo
- Department of Chemistry and Chemical Biology, Rutgers University , 610 Taylor Road, Piscataway, New Jersey 08854, United States
| | - M Reza Khoshi
- Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States
| | - Emann Rabie
- Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States
| | - Qing Zhang
- Department of Chemistry, Jilin University , 2699 Qianjin Street, Changchun 130012, P. R. China
| | - Carol R Flach
- Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States
| | - Richard Mendelsohn
- Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States
| | - Eric Garfunkel
- Department of Chemistry and Chemical Biology, Rutgers University , 610 Taylor Road, Piscataway, New Jersey 08854, United States
| | - Michal Szostak
- Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States
| | - Huixin He
- Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States
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9
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Mendelsohn R, Rabie E, Walters RM, Flach CR. Fatty Acid Chain Length Dependence of Phase Separation Kinetics in Stratum Corneum Models by IR Spectroscopy. J Phys Chem B 2015; 119:9740-50. [DOI: 10.1021/acs.jpcb.5b03045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Richard Mendelsohn
- Department
of Chemistry, Newark College, Rutgers University, Newark, New Jersey 07102, United States
| | - Emann Rabie
- Department
of Chemistry, Newark College, Rutgers University, Newark, New Jersey 07102, United States
| | - Russel M. Walters
- Johnson
and Johnson
Consumer Companies, Inc., 199 Grandview
Road, Skillman, New Jersey 08558, United States
| | - Carol R. Flach
- Department
of Chemistry, Newark College, Rutgers University, Newark, New Jersey 07102, United States
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10
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Zhang Q, Flach CR, Mendelsohn R, Mao G, Pappas A, Mack MC, Walters RM, Southall MD. Topically applied ceramide accumulates in skin glyphs. Clin Cosmet Investig Dermatol 2015; 8:329-37. [PMID: 26170709 PMCID: PMC4493983 DOI: 10.2147/ccid.s83857] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Ceramides (CERs), structural components of the stratum corneum (SC), impart essential barrier properties to this thin outer layer of the epidermis. Variations in CER species within this layer have been linked to several skin diseases. A recent proliferation of CER-containing topical skin-care products warrants the elucidation of CER penetration profiles in both healthy and diseased skin. In the current study, the spatial distributions of CER concentration profiles, following topical application of two species of CER, were tracked using infrared imaging. Suspensions of single-chain perdeuterated sphingosine and phytosphingosine CER in oleic acid were applied, in separate experiments, to the surface of healthy intact ex vivo human skin using Franz diffusion cells. Following either a 24- or 48-hour incubation period at 34°C, infrared images were acquired from microtomed skin sections. Both CER species accumulated in glyph regions of the skin and penetrated into the SC, to a limited extent, only in these regions. The concentration profiles observed herein were independent of the CER species and incubation time utilized in the study. As a result, a very heterogeneous, sparse, spatial distribution of CERs in the SC was revealed. In contrast, oleic acid was found to be fairly homogeneously distributed throughout the SC and viable epidermis, albeit at lower concentrations in the latter. A more uniform, lateral distribution of CERs in the SC would likely be important for barrier efficacy or enhancement.
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Affiliation(s)
- Qihong Zhang
- Department of Chemistry, Rutgers University, Newark, NJ, USA
| | - Carol R Flach
- Department of Chemistry, Rutgers University, Newark, NJ, USA
| | | | - Guangru Mao
- Johnson & Johnson Consumer Companies, Inc., Skillman, NJ, USA
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11
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Mack Correa MC, Mao G, Saad P, Flach CR, Mendelsohn R, Walters RM. Molecular interactions of plant oil components with stratum corneum lipids correlate with clinical measures of skin barrier function. Exp Dermatol 2014; 23:39-44. [PMID: 24372651 PMCID: PMC4068283 DOI: 10.1111/exd.12296] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/29/2013] [Indexed: 02/01/2023]
Abstract
Plant-derived oils consisting of triglycerides and small amounts of free fatty acids (FFAs) are commonly used in skincare regimens. FFAs are known to disrupt skin barrier function. The objective of this study was to mechanistically study the effects of FFAs, triglycerides and their mixtures on skin barrier function. The effects of oleic acid (OA), glyceryl trioleate (GT) and OA/GT mixtures on skin barrier were assessed in vivo through measurement of transepidermal water loss (TEWL) and fluorescein dye penetration before and after a single application. OA's effects on stratum corneum (SC) lipid order in vivo were measured with infrared spectroscopy through application of perdeuterated OA (OA-d34 ). Studies of the interaction of OA and GT with skin lipids included imaging the distribution of OA-d34 and GT ex vivo with IR microspectroscopy and thermodynamic analysis of mixtures in aqueous monolayers. The oil mixtures increased both TEWL and fluorescein penetration 24 h after a single application in an OA dose-dependent manner, with the highest increase from treatment with pure OA. OA-d34 penetrated into skin and disordered SC lipids. Furthermore, the ex vivo IR imaging studies showed that OA-d34 permeated to the dermal/epidermal junction while GT remained in the SC. The monolayer experiments showed preferential interspecies interactions between OA and SC lipids, while the mixing between GT and SC lipids was not thermodynamically preferred. The FFA component of plant oils may disrupt skin barrier function. The affinity between plant oil components and SC lipids likely determines the extent of their penetration and clinically measurable effects on skin barrier functions.
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12
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Zhang Q, Saad P, Mao G, Walters RM, Mack Correa MC, Mendelsohn R, Flach CR. Infrared spectroscopic imaging tracks lateral distribution in human stratum corneum. Pharm Res 2014; 31:2762-73. [PMID: 24792828 DOI: 10.1007/s11095-014-1373-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 03/21/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE To demonstrate the efficacy of infrared (IR) spectroscopic imaging for evaluation of lateral diffusion in stratum corneum (SC) and for elucidation of intermolecular interactions between exogenous agents and SC constituents. METHODS In separate experiments, acyl chain perdeuterated oleic acid (OA-d) and deuterated dimethyl sulfoxide (DMSO-d) were applied to the surface of isolated human SC. The lateral distribution of permeant concentrations was monitored using the time-dependence of IR images. Diffusion coefficients (D) were estimated from Fick's second law. Interactions between the exogenous agents and the SC were tracked from changes in CD2 and Amide I stretching frequencies. RESULTS Networked glyphs served as the major pathway for lateral distribution of OA-d. In glyph-poor regions, D values from 0.3-1 × 10(-8) cm(2)/s bracketed the OA-d data and apparently decreased with time. Although diffusion of DMSO-d is relatively fast compared to our experimental measurement time, the results suggest values of ~10(-7) cm(2)/s. OA-d spectral changes suggest penetration into the ordered lipids of the SC; DMSO-d penetration results in perturbation of SC keratin structure. CONCLUSIONS IR imaging provides concentration profiles, diffusion coefficients, and unique molecular level information about structural changes in the endogenous SC constituents and exogenous agents upon their mutual interaction. Transport along glyphs is the dominant mode of distribution for OA-d.
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Affiliation(s)
- Qihong Zhang
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey, 07102, USA
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13
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Mendelsohn R, Selevany I, Moore DJ, Mack Correa MC, Mao G, Walters RM, Flach CR. Kinetic Evidence Suggests Spinodal Phase Separation in Stratum Corneum Models by IR Spectroscopy. J Phys Chem B 2014; 118:4378-87. [DOI: 10.1021/jp501003c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Richard Mendelsohn
- Department
of Chemistry, Newark College, Rutgers University, Newark, New Jersey 07102, United States
| | - Ibrahim Selevany
- Department
of Chemistry, Newark College, Rutgers University, Newark, New Jersey 07102, United States
| | - David J. Moore
- Department
of Chemistry, Newark College, Rutgers University, Newark, New Jersey 07102, United States
| | - M. Catherine Mack Correa
- Johnson & Johnson Consumer Companies, Inc., 199 Grandview Road, Skillman, New Jersey 08558, United States
| | - Guangru Mao
- Johnson & Johnson Consumer Companies, Inc., 199 Grandview Road, Skillman, New Jersey 08558, United States
| | - Russel M. Walters
- Johnson & Johnson Consumer Companies, Inc., 199 Grandview Road, Skillman, New Jersey 08558, United States
| | - Carol R. Flach
- Department
of Chemistry, Newark College, Rutgers University, Newark, New Jersey 07102, United States
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14
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Mendelsohn R, Selevany I, Mao G, Mack Correa MC, Walters RM, Moore DJ, Flach CR. Kinetic Mechanism of Phase Separation in Stratum Corneum Models by IR Spectroscopy. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.3902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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15
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Patel MA, Yang H, Chiu PL, Mastrogiovanni DDT, Flach CR, Savaram K, Gomez L, Hemnarine A, Mendelsohn R, Garfunkel E, Jiang H, He H. Direct production of graphene nanosheets for near infrared photoacoustic imaging. ACS Nano 2013; 7:8147-8157. [PMID: 24001023 DOI: 10.1021/nn403429v] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Hummers method is commonly used for the fabrication of graphene oxide (GO) from graphite particles. The oxidation process also leads to the cutting of graphene sheets into small pieces. From a thermodynamic perspective, it seems improbable that the aggressive, somewhat random oxidative cutting process could directly result in graphene nanosheets without destroying the intrinsic π-conjugated structures and the associated exotic properties of graphene. In Hummers method, both KMnO4 and NO2(+) (nitronium ions) in concentrated H2SO4 solutions act as oxidants via different oxidation mechanisms. From both experimental observations and theoretical calculations, it appears that KMnO4 plays a major role in the observed oxidative cutting and unzipping processes. We find that KMnO4 also limits nitronium oxidative etching of graphene basal planes, therefore slowing down graphene fracturing processes for nanosheet fabrication. By intentionally excluding KMnO4 and exploiting pure nitronium ion oxidation, aided by the unique thermal and kinetic effects induced by microwave heating, we find that graphite particles can be converted into graphene nanosheets with their π-conjugated aromatic structures and properties largely retained. Without the need of any postreduction processes to remove the high concentration of oxygenated groups that results from Hummers GO formation, the graphene nanosheets as-fabricated exhibit strong absorption, which is nearly wavelength-independent in the visible and near-infrared (NIR) regions, an optical property typical for intrinsic graphene sheets. For the first time, we demonstrate that strong photoacoustic signals can be generated from these graphene nanosheets with NIR excitation. The photo-to-acoustic conversion is weakly dependent on the wavelength of the NIR excitation, which is different from all other NIR photoacoustic contrast agents previously reported.
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Affiliation(s)
- Mehulkumar A Patel
- Chemistry Department, Rutgers University , Newark, New Jersey 07102, United States
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16
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Yu G, Zhang G, Flach CR, Mendelsohn R. Vibrational spectroscopy and microscopic imaging: novel approaches for comparing barrier physical properties in native and human skin equivalents. J Biomed Opt 2013; 18:061207. [PMID: 23165761 DOI: 10.1117/1.jbo.18.6.061207] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Vibrational spectroscopy and imaging have been used to compare barrier properties in human skin, porcine skin, and two human skin equivalents, Epiderm 200X with an enhanced barrier and Epiderm 200 with a normal barrier. Three structural characterizations were performed. First, chain packing and conformational order were compared in isolated human stratum corneum (SC), isolated porcine SC, and in the Epiderm 200X surface layers. The infrared (IR) spectrum of isolated human SC revealed a large proportion of orthorhombically packed lipid chains at physiological temperatures along with a thermotropic phase transition to a state with hexagonally packed chains. In contrast, the lipid phase at physiological temperatures in both porcine SC and in Epiderm 200X, although dominated by conformationally ordered chains, lacked significant levels of orthorhombic subcell packing. Second, confocal Raman imaging of cholesterol bands showed extensive formation of cholesterol-enriched pockets within the human skin equivalents (HSEs). Finally, IR imaging tracked lipid barrier dimensions as well as the spatial disposition of ordered lipids in human SC and Epiderm 200X. These approaches provide a useful set of experiments for exploring structural differences between excised human skin and HSEs, which in turn may provide a rationale for the functional differences observed among these preparations.
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Affiliation(s)
- Guo Yu
- Rutgers University, Department of Chemistry, Newark, New Jersey 07103, USA
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17
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Spevak L, Flach CR, Hunter T, Mendelsohn R, Boskey A. Fourier transform infrared spectroscopic imaging parameters describing acid phosphate substitution in biologic hydroxyapatite. Calcif Tissue Int 2013; 92:418-28. [PMID: 23380987 PMCID: PMC3631290 DOI: 10.1007/s00223-013-9695-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 12/14/2012] [Indexed: 12/13/2022]
Abstract
Acid phosphate substitution into mineralized tissues is an important determinant of their mechanical properties and their response to treatment. This study identifies and validates Fourier transform infrared spectroscopic imaging (FTIRI) spectral parameters that provide information on the acid phosphate (HPO4) substitution into hydroxyapatite in developing mineralized tissues. Curve fitting and Fourier self-deconvolution were used to identify subband positions in model compounds (with and without HPO4). The intensity of subbands at 1127 and 1110 cm(-1) correlated with the acid phosphate content in these models. Peak height ratios of these subbands to the ν3 vibration at 1096 cm(-1) found in stoichiometric apatite were evaluated in the model compounds and mixtures thereof. FTIRI spectra of bones and teeth at different developmental ages were analyzed using these spectral parameters. Factor analysis (a chemometric technique) was also conducted on the tissue samples and resulted in factor loadings with spectral features corresponding to the HPO4 vibrations described above. Images of both factor correlation coefficients and the peak height ratios 1127/1096 and 1112/1096 cm(-1) demonstrated higher acid phosphate content in younger vs. more mature regions in the same specimen. Maps of the distribution of acid phosphate content will be useful for characterizing the extent of new bone formation, the areas of potential decreased strength, and the effects of therapies such as those used in metabolic bone diseases (osteoporosis, chronic kidney disease) on mineral composition. Because of the wider range of values obtained with the 1127/1096 cm(-1) parameter compared to the 1110/1096 cm(-1) parameter and the smaller scatter in the slope, it is suggested that this ratio should be the parameter of choice.
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Affiliation(s)
- Lyudmila Spevak
- Hospital for Special Surgery, 535 E. 70th Street, New York, NY 10021, USA
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18
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Mao G, VanWyck D, Xiao X, Mack Correa MC, Gunn E, Flach CR, Mendelsohn R, Walters RM. Oleic acid disorders stratum corneum lipids in Langmuir monolayers. Langmuir 2013; 29:4857-4865. [PMID: 23517601 DOI: 10.1021/la4002384] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Oleic acid (OA) is well-known to affect the function of the skin barrier. In this study, the molecular interactions between OA and model stratum corneum (SC) lipids consisting of ceramide, cholesterol, and palmitic acid (PA) were investigated with Langmuir monolayer and associated techniques. Mixtures with different OA/SC lipid compositions were spread at the air/water interface, and the phase behavior was tracked with surface pressure-molecular area (π-A) isotherms. With increasing OA levels in the monolayer, the films became more fluid and more compressible. The thermodynamic parameters derived from π-A isotherms indicated that there are preferential interactions between OA and SC lipids and that films of their mixtures were thermodynamically stable. The domain structure and lipid conformational order of the monolayers were studied through Brewster angle microscopy (BAM) and infrared reflection absorption spectroscopy (IRRAS), respectively. Results indicate that lower concentrations of OA preferentially mix with and disorder the ceramide-enriched domains, followed by perturbation of the PA-enriched domains and disruption of SC lipid domain separation at higher OA levels.
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Affiliation(s)
- Guangru Mao
- Johnson and Johnson Consumer Companies, Incorporated , 199 Grandview Road, Skillman, New Jersey 08558, United States.
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Mao G, VanWyck D, Xiao X, Gunn E, Flach CR, Mendelsohn R, Walters RM. Effects of Oleic Acid on Stratum Corneum Lipids in Langmuir Monolayers. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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20
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Flach CR, Moore DJ. Infrared and Raman imaging spectroscopy of ex vivo skin. Int J Cosmet Sci 2012; 35:125-35. [DOI: 10.1111/ics.12020] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 10/16/2012] [Indexed: 11/29/2022]
Affiliation(s)
- Carol R. Flach
- Department of Chemistry; Rutgers University; 73 Warren Street; Newark; NJ; USA
| | - David J. Moore
- Center for Skin Science and Applied Dermatology; TRI/Princeton; 601 Prospect Avenue; Princeton; NJ; USA
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21
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Yu G, Stojadinovic O, Tomic-Canic M, Flach CR, Mendelsohn R. Infrared microscopic imaging of cutaneous wound healing: lipid conformation in the migrating epithelial tongue. J Biomed Opt 2012; 17:96009-1. [PMID: 23085910 DOI: 10.1117/1.jbo.17.9.096009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Infrared microscopic imaging has been utilized to analyze for the first time the spatial distribution of lipid structure in an ex vivo human organ culture skin wound healing model. Infrared images were collected at zero, two, four, and six days following wounding. Analysis of lipid infrared spectral properties revealed the presence of a lipid class with disordered chains within and in the vicinity of the migrating epithelial tongue. The presence of lipid ester C=O bands colocalized with the disordered chains provided evidence for the presence of carbonyl-containing lipid species. Gene array data complemented the biophysical studies and provided a biological rationale for the generation of the disordered chain species. This is the first clear observation, to our knowledge, of disordered lipid involvement in cutaneous wound healing. Several possibilities are discussed for the biological relevance of these observations.
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Affiliation(s)
- Guo Yu
- Rutgers University, Newark College of Arts and Science, Department of Chemistry, 73 Warren Street, Newark, New Jersey 07102, USA
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22
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Mao G, Flach CR, Mendelsohn R, Walters RM. Imaging the distribution of sodium dodecyl sulfate in skin by confocal Raman and infrared microspectroscopy. Pharm Res 2012; 29:2189-201. [PMID: 22477073 PMCID: PMC3399083 DOI: 10.1007/s11095-012-0748-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 03/22/2012] [Indexed: 01/06/2023]
Abstract
Purpose To image SDS distribution across different skin regions, to compare the permeability difference between porcine and human skin, and to evaluate the interaction between SDS and skin. Methods Full thickness porcine and human skin was treated with acyl chain perdeuterated SDS (SDS-d25) at room temperature and at 34 °C for 3, 24 and 40 h. SDS distribution in skin was monitored by confocal Raman and IR microspectroscopic imaging. Permeation profiles of SDS-d25 in skin were derived from the band intensities of the CD2 stretching vibrations. The interaction between SDS and skin was monitored through the CH2 and CD2 stretching frequencies and the Amide I and II spectral region. Results SDS-d25 penetrates both porcine and human skin in a time and temperature-dependent manner, with slightly higher permeability through the stratum corneum (SC) in porcine skin. When SDS permeates into the SC, its chains are more ordered compared to SDS micelles. The secondary structure of keratin in the SC is not affected by SDS-d25. Conclusion The spatial distribution of SDS-d25 in skin was obtained for the first time. Infrared microscopic imaging provides unique opportunities to measure concentration profiles of exogenous materials in skin and offers insights to interaction between permeants and skin. Electronic supplementary material The online version of this article (doi:10.1007/s11095-012-0748-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- G Mao
- Johnson & Johnson Consumer Companies, Inc., 199 Grandview Rd., Skillman, New Jersey 08558-9418, USA.
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23
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Chiu PL, Mastrogiovanni DDT, Wei D, Louis C, Jeong M, Yu G, Saad P, Flach CR, Mendelsohn R, Garfunkel E, He H. Microwave- and nitronium ion-enabled rapid and direct production of highly conductive low-oxygen graphene. J Am Chem Soc 2012; 134:5850-6. [PMID: 22385480 DOI: 10.1021/ja210725p] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Currently the preferred method for large-scale production of solution-processable graphene is via a nonconductive graphene oxide (GO) pathway, which uncontrollably cuts sheets into small pieces and/or introduces nanometer-sized holes in the basal plane. These structural changes significantly decrease some of graphene's remarkable electrical and mechanical properties. Here, we report an unprecedented fast and scalable approach to avoid these problems and directly produce large, highly conductive graphene sheets. This approach intentionally excludes KMnO(4) from Hummers' methods and exploits aromatic oxidation by nitronium ions combined with the unique properties of microwave heating. This combination promotes rapid and simultaneous oxidation of multiple non-neighboring carbon atoms across an entire graphene sheet, thereby producing only a minimum concentration of oxygen moieties sufficient to enable the separation of graphene sheets. Thus, separated graphene sheets, which are referred to as microwave-enabled low-oxygen graphene, are thermally stable and highly conductive without requiring further reduction. Even in the absence of polymeric or surfactant stabilizers, concentrated dispersions of graphene with clean and well-separated graphene sheets can be obtained in both aqueous and organic solvents. This rapid and scalable approach produces high-quality graphene sheets of low oxygen content, enabling a broad spectrum of applications via low-cost solution processing.
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Affiliation(s)
- Pui Lam Chiu
- Chemistry Department, Rutgers University, Newark, New Jersey 07102, USA
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24
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Zhang Q, Andrew Chan KL, Zhang G, Gillece T, Senak L, Moore DJ, Mendelsohn R, Flach CR. Raman microspectroscopic and dynamic vapor sorption characterization of hydration in collagen and dermal tissue. Biopolymers 2011; 95:607-15. [DOI: 10.1002/bip.21618] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 02/23/2011] [Accepted: 02/23/2011] [Indexed: 11/08/2022]
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25
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Zhang Q, Chan KA, Zhang G, Gillece T, Senak L, Moore DJ, Mendelsohn R, Flach CR. Confocal Raman Spectroscopy of Collagen Hydration: from Human Type I Collagen to Dermal Tissue. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.1913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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26
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Mendelsohn R, Mao G, Flach CR. Infrared reflection-absorption spectroscopy: principles and applications to lipid-protein interaction in Langmuir films. Biochim Biophys Acta 2010; 1798:788-800. [PMID: 20004639 DOI: 10.1016/j.bbamem.2009.11.024] [Citation(s) in RCA: 160] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 11/19/2009] [Accepted: 11/24/2009] [Indexed: 01/08/2023]
Abstract
Infrared reflection-absorption spectroscopy (IRRAS) of lipid/protein monolayer films in situ at the air/water interface provides unique molecular structure and orientation information from the film constituents. The technique is thus well suited for studies of lipid/protein interaction in a physiologically relevant environment. Initially, the nature of the IRRAS experiment is described and the molecular structure information that may be obtained is recapitulated. Subsequently, several types of applications, including the determination of lipid chain conformation and tilt as well as elucidation of protein secondary structure are reviewed. The current article attempts to provide the reader with an understanding of the current capabilities of IRRAS instrumentation and the type of results that have been achieved to date from IRRAS studies of lipids, proteins, and lipid/protein films of progressively increasing complexity. Finally, possible extensions of the technology are briefly considered.
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Affiliation(s)
- Richard Mendelsohn
- Department of Chemistry, Newark College, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA.
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27
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Saad P, Moore D, Moore DJ, Flach E, Flach CR, Mendelsohn R. Quantitative IR Spectroscopy Studies of Changes in Lipid Dynamics and Organization in Isolated Stratum Corneum Exposed to Basic pH. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.1501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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28
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Andrew Chan KL, Zhang G, Tomic-Canic M, Stojadinovic O, Lee B, Flach CR, Mendelsohn R. A coordinated approach to cutaneous wound healing: vibrational microscopy and molecular biology. J Cell Mol Med 2009; 12:2145-54. [PMID: 19145704 PMCID: PMC4506178 DOI: 10.1111/j.1582-4934.2008.00459.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The repair of cutaneous wounds in the adult body involves a complex series of spatially and temporally organized processes to prevent infection and restore homeostasis. Three characteristic phases of wound repair (inflammation, proliferation including re-epithelialization and remodelling) overlap in time and space. We have utilized a human skin wound-healing model to correlate changes in genotype and pheno-type with infrared (IR) and confocal Raman spectroscopic images during the re-epithelialization of excisional wounds. The experimental protocols validated as IR images clearly delineate the keratin-rich migrating epithelial tongue from the collagen-rich wound bed. Multivariate statistical analysis of IR datasets acquired 6 days post-wounding reveal subtle spectral differences that map to distinct spatial distributions, which are correlated with immunofluorescent staining patterns of different keratin types. Images computed within collagen-rich regions expose complementary spatial patterns and identify elastin in the wound bed. The temporal sequence of events is explored through a comparison of gene array analysis with confocal Raman microscopy. Our approach demonstrates the feasibility of acquiring detailed molecular structure information from the various proteins and their subclasses involved in the wound-healing process.
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Affiliation(s)
- K L Andrew Chan
- Department of Chemical Engineering, Imperial College London, London, SW72AZ, UK
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29
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Mao G, Wang L, Brauner JW, McCormack FX, Crouch E, Seaton B, Head J, Smith K, Flach CR, Mendelsohn R. IRRAS Studies of the Host Defense Effect of Pulmonary Surfactants SP-A and SP-D. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.3115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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30
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Wang L, Brauner JW, Mao G, Crouch E, Seaton B, Head J, Smith K, Flach CR, Mendelsohn R. Interaction of recombinant surfactant protein D with lipopolysaccharide: conformation and orientation of bound protein by IRRAS and simulations. Biochemistry 2008; 47:8103-13. [PMID: 18620419 DOI: 10.1021/bi800626h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Effective innate host defense requires early recognition of pathogens. Surfactant protein D (SP-D), shown to play a role in host defense, binds to the lipopolysaccharide (LPS) component of Gram-negative bacterial membranes. Binding takes place via the carbohydrate recognition domain (CRD) of SP-D. Recombinant trimeric neck+CRDs (NCRD) have proven valuable in biophysical studies of specific interactions. Although X-ray crystallography has provided atomic level information on NCRD binding to carbohydrates and other ligands, molecular level information about interactions between SP-D and biological ligands under physiologically relevant conditions is lacking. Infrared reflection-absorption spectroscopy (IRRAS) provides molecular structure information from films at the air/water interface where protein adsorption to LPS monolayers serves as a model for protein-lipid interaction. In the current studies, we examine the adsorption of NCRDs to Rd 1 LPS monolayers using surface pressure measurements and IRRAS. Measurements of surface pressure, Amide I band intensities, and LPS acyl chain conformational ordering, along with the introduction of EDTA, permit discrimination of Ca (2+)-mediated binding from nonspecific protein adsorption. The findings support the concept of specific binding between the CRD and heptoses in the core region of LPS. In addition, a novel simulation method that accurately predicts the IR Amide I contour from X-ray coordinates of NCRD SP-D is applied and coupled to quantitative IRRAS equations providing information on protein orientation. Marked differences in orientation are found when the NCRD binds to LPS compared to nonspecific adsorption. The geometry suggests that all three CRDs are simultaneously bound to LPS under conditions that support the Ca (2+)-mediated interaction.
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Affiliation(s)
- Lin Wang
- Department of Chemistry, Newark College of Arts and Science, Rutgers University, Newark, New Jersey 07102, USA
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Mao G, Desai J, Flach CR, Mendelsohn R. Structural characterization of the monolayer-multilayer transition in a pulmonary surfactant model: IR studies of films transferred at continuously varying surface pressures. Langmuir 2008; 24:2025-2034. [PMID: 18198907 DOI: 10.1021/la702612p] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The four-component system acyl chain perdeuterated 1,2-dipalmitoylphosphatidylcholine (DPPC)/1,2-dipalmitoylphosphatidylglycerol/ (DPPG)/pulmonary surfactant protein SP-C/cholesterol provides a useful model for in vitro biophysical studies of the reversible monolayer to multilayer transition that occurs during compression <--> expansion cycles in the lung. Monolayer films of this mixture (with chain perdeuterated DPPC-d62) at the air/water interface have been transferred to solid substrates under conditions of continuously varying surface pressure, an approach termed COVASP (continuously varying surface pressures) (Langmuir 2007, 23, 4958). The thermodynamic properties of the Langmuir films have been examined with pressure-area isotherms, while the molecular properties of the film constituents in the transferred films in the monolayer and multilayer phases have been examined with IR spectroscopy. Quantitative intensity measurements of the DPPC-d62, DPPG, and SP-C components in each phase reveal that the DPPG and SP-C constituents are relatively enriched in the multilayer compared with the DPPC-d62, although all three species are present in both phases. Some molecular structure information is available from the surface-pressure-induced variation in IR parameters. The DPPC-d62 exhibits slightly increased conformational order in the multilayer phase as detected from decreases in the CD2 stretching frequencies upon compression, while the lipid phosphate residues become dehydrated, as deduced from increases in the 1245 cm-1 symmetric PO2- stretching frequency. A small increase is observed in the protein amide I frequency; possible interpretations of these changes are presented. The current observations are compared with ideas contained in the "squeeze-out hypothesis" (Handbook of Physiology, The Respiratory System; American Physiological Society Press: Bethesda, MD, 1986; Vol. III, p 247) and in the "liquid crystalline collapse" model (Biophys. J. 2003, 84, 3792). Within the limitation of the current procedures, the data contain elements from both these descriptions of the monolayer transformation. Extensions and possible limitations of the COVASP-IR method are discussed.
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Affiliation(s)
- Guangru Mao
- Department of Chemistry, Olson Hall, Newark College, Rutgers University, Newark, New Jersey 07102, USA
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Zhang G, Flach CR, Mendelsohn R. Tracking the dephosphorylation of resveratrol triphosphate in skin by confocal Raman microscopy. J Control Release 2007; 123:141-7. [PMID: 17826862 PMCID: PMC2096630 DOI: 10.1016/j.jconrel.2007.08.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Revised: 07/18/2007] [Accepted: 08/02/2007] [Indexed: 11/24/2022]
Abstract
Polyphenolic resveratrol has been identified as a potent antioxidant acting as both a free radical scavenger and an inhibitor of enzyme oxidative activity. However, the reactive propensity of resveratrol also limits its use in topical formulations. A transient derivative of resveratrol, resveratrol triphosphate, has been designed to provide a means for the delayed delivery of the active compound in skin tissue where endogenous enzymes capable of dephosphorylation reside. Confocal Raman microscopy studies of intact pigskin biopsies treated with modified resveratrol provided information about the spatial distribution and time-dependence of permeation and conversion to the native active form. Conversion to the active form was not observed when skin samples were exposed to steam, a procedure that likely inactivates endogenous skin enzymes. In addition, treatment with the triphosphate compared to the parent compound revealed a more homogeneous distribution of resveratrol throughout the stratum corneum and viable epidermis when the former was applied. Thus, the bioavailability of resveratrol in the epidermis appears to be enhanced upon application of the pro-molecule compared to resveratrol.
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Affiliation(s)
| | - Carol R. Flach
- Corresponding author: Tel.:973-353-1330; Fax: 973-353-1264; e-mail:
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33
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Bryan MA, Brauner JW, Anderle G, Flach CR, Brodsky B, Mendelsohn R. FTIR studies of collagen model peptides: complementary experimental and simulation approaches to conformation and unfolding. J Am Chem Soc 2007; 129:7877-84. [PMID: 17550251 PMCID: PMC2570338 DOI: 10.1021/ja071154i] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
X-ray crystallography of collagen model peptides has provided high-resolution structures of the basic triple-helical conformation and its water-mediated hydration network. Vibrational spectroscopy provides a useful bridge for transferring the structural information from X-ray diffraction to collagen in its native environment. The vibrational mode most useful for this purpose is the amide I mode (mostly peptide bond C=O stretch) near 1650 cm-1. The current study refines and extends the range of utility of a novel simulation method that accurately predicts the infrared (IR) amide I spectral contour from the three-dimensional structure of a protein or peptide. The approach is demonstrated through accurate simulation of the experimental amide I contour in solution for both a standard triple helix, (Pro-Pro-Gly)10, and a second peptide with a Gly --> Ala substitution in the middle of the chain that models the effect of a mutation in the native collagen sequence. Monitoring the major amide I peak as a function of temperature gives sharp thermal transitions for both peptides, similar to those obtained by circular dichroism spectroscopy, and the Fourier transform infrared (FTIR) spectra of the unfolded states were compared with polyproline II. The simulation studies were extended to model early stages of thermal denaturation of (Pro-Pro-Gly)10. Dihedral angle changes suggested by molecular dynamics simulations were made in a stepwise fashion to generate peptide unwinding from each end, which emulates the effect of increasing temperature. Simulated bands from these new structures were then compared to the experimental bands obtained as temperature was increased. The similarity between the simulated and experimental IR spectra lends credence to the simulation method and paves the way for a variety of applications.
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Affiliation(s)
- Michael A. Bryan
- Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey
| | - Joseph W. Brauner
- Department of Chemistry, Newark College of Arts and Science, Rutgers University, New Jersey
| | - Gloria Anderle
- Department of Chemistry and Geology, Becton College, Fairleigh Dickinson University, Madison, New Jersey
| | - Carol R. Flach
- Department of Chemistry, Newark College of Arts and Science, Rutgers University, New Jersey
| | - Barbara Brodsky
- Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey
| | - Richard Mendelsohn
- Department of Chemistry, Newark College of Arts and Science, Rutgers University, New Jersey
- corresponding author,
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34
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Wang L, Cruz A, Flach CR, Pérez-Gil J, Mendelsohn R. Langmuir-Blodgett films formed by continuously varying surface pressure. Characterization by IR spectroscopy and epifluorescence microscopy. Langmuir 2007; 23:4950-8. [PMID: 17388613 DOI: 10.1021/la063139h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Monolayer films of phospholipids at the air-water interface have been transferred to solid substrates under conditions of continuously varying surface pressure, an approach termed COVASP. The molecular and supramolecular properties of the film constituents have been characterized with two complementary techniques. IR spectroscopy was used to monitor chain conformation as a function of transfer surface pressure. Results were compared to those from Langmuir films determined directly at the A/W interface by IR reflection-absorption spectroscopy (IRRAS). The methylene stretching frequencies for both proteated and acyl chain perdeuterated 1,2-dipalmitoylphosphatidylcholine (DPPC and DPPC-d62) in the transferred molecules indicate that the phospholipids retain at least, in part, their surface pressure-dependent chain-conformational order characteristics. The line widths of these modes are somewhat reduced, suggestive of slower rates of reorientational motion in the Langmuir-Blodgett (LB) films. Epifluorescence microscopy reveals a progressive condensation gradient, including nucleation and growth of probe-excluding condensed domains along the transfer line. DPPC condensation, observed along a single LB film, was qualitatively comparable to compression-driven condensation as observed in situ or in conventional LB films transferred at constant pressures. However, condensation along the compression isotherm in COVASP-LB films was reduced by 15-20% as compared to films equilibrated at different constant pressures, probably the result of kinetic differences in equilibration processes. As a preliminary demonstration of the utility of this new approach, the monolayer --> multilayer transition known to occur (Eur. Biophys. J. 2005, 34, 243) in a four-component model for pulmonary surfactant has been examined. IR parameters from both the lipid and the protein constituents of the film all indicate that the transition persists during the transfer process. This new approach for the study of transferred films will permit the efficient characterization of lipid-protein interactions and structural transitions occurring in pulmonary surfactant films subjected to dynamic compression.
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Affiliation(s)
- Lin Wang
- Department of Chemistry, Olson Hall, Newark College, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, USA
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35
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Zhang G, Moore DJ, Sloan KB, Flach CR, Mendelsohn R. Imaging the prodrug-to-drug transformation of a 5-fluorouracil derivative in skin by confocal Raman microscopy. J Invest Dermatol 2007; 127:1205-9. [PMID: 17218938 DOI: 10.1038/sj.jid.5700690] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The widespread adoption of transdermal drug delivery has been limited by the barrier properties of the outermost layer of the epidermis, the stratum corneum (SC). A variety of approaches have been developed to overcome the barrier, including the use of a prodrug form of an active therapeutic agent to enhance transdermal delivery. Once in the epidermis, the pro-molecule is converted to the active drug by endogenous enzymes or simple chemical hydrolysis. The prodrug selected for the current studies, 1-ethyloxycarbonyl-5-fluorouracil, is known to enhance transdermal delivery of 5-fluorouracil, an important systemic antitumor drug. Using confocal Raman microscopy on pigskin biopsies treated with prodrug, we are able to image the spatial distribution of both prodrug and drug in the SC and viable epidermis, thereby providing information about permeation and metabolism. This approach may readily be extended to a variety of dermatological processes.
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Affiliation(s)
- Guojin Zhang
- Department of Chemistry, Newark College of Arts and Sciences, Rutgers University, Newark, New Jersey 07102, USA
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36
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Zhang G, Moore DJ, Flach CR, Mendelsohn R. Vibrational microscopy and imaging of skin: from single cells to intact tissue. Anal Bioanal Chem 2006; 387:1591-9. [PMID: 17160382 PMCID: PMC1802726 DOI: 10.1007/s00216-006-0852-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Revised: 09/07/2006] [Accepted: 09/08/2006] [Indexed: 11/26/2022]
Abstract
Vibrational microscopy and imaging offer several advantages for a variety of dermatological applications, ranging from studies of isolated single cells (corneocytes) to characterization of endogenous components in intact tissue. Two applications are described to illustrate the power of these techniques for skin research. First, the feasibility of tracking structural alterations in the components of individual corneocytes is demonstrated. Two solvents, DMSO and chloroform/methanol, commonly used in dermatological research, are shown to induce large reversible alterations (α-helix to β-sheet) in the secondary structure of keratin in isolated corneocytes. Second, factor analysis of image planes acquired with confocal Raman microscopy to a depth of 70 μm in intact pigskin, demonstrates the delineation of specific skin regions. Two particular components that are difficult to identify by other means were observed in the epidermis. One small region was formed from a conformationally ordered lipid phase containing cholesterol. In addition, the presence of nucleated cells in the tissue (most likely keratinocytes) was revealed by the spectral signatures of the phosphodiester and cytosine moieties of cellular DNA.
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Affiliation(s)
- Guojin Zhang
- Department of Chemistry, Newark College of Arts and Sciences, Rutgers University, Newark, NJ 07102 USA
| | | | - Carol R. Flach
- Department of Chemistry, Newark College of Arts and Sciences, Rutgers University, Newark, NJ 07102 USA
| | - Richard Mendelsohn
- Department of Chemistry, Newark College of Arts and Sciences, Rutgers University, Newark, NJ 07102 USA
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37
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Na Nakorn P, Meyer MC, Flach CR, Mendelsohn R, Galla HJ. Surfactant protein C and lung function: new insights into the role of α-helical length and palmitoylation. Eur Biophys J 2006; 36:477-89. [PMID: 17051367 DOI: 10.1007/s00249-006-0102-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Revised: 08/28/2006] [Accepted: 09/05/2006] [Indexed: 10/24/2022]
Abstract
Surfactant protein C (SP-C) is known to be essential for lung function and the formation of a surface confined reservoir at the alveolar interface. The structural features relevant for the peptide's extraordinary ability to form extended three-dimensional structures were systematically investigated and are summarized in the present paper. The influence of palmitoylation was studied for full length SP-Cs as well as truncated variants with the N-terminal residues 1-17 and 1-13, respectively. The combined results from film balance measurements, fluorescence microscopy (FLM) and scanning force microscopy (SFM) reveal a fine-tuned balance between the influence of the palmitoyl chains and alpha-helical length. Native SP-C added to DPPC/DPPG monolayers (molar ratio 80:20) induced the formation of the surface confined reservoir independent of its palmitoylation degree. However, topographic images revealed that only bilayers and not multilayers where formed when the acyl chains were missing. The influence of palmitoylation increased when alpha-helical length was considerably reduced to 17 or even 13 amino acid residues. In these strongly truncated SP-C peptides palmitoyl chains increased monolayer stability and anchored the peptides in the lipid film. However, no multilayer formation was observed at all for all shortened peptides. The alpha-helix of SP-C seems to be a prerequisite for the formation of extended three-dimensional structures and obviously has to be able to span a lipid bilayer. Palmitoylation obviously mediates interactions between lipids and/or peptides not only within a protein/lipid film but also between neighbouring layers and induces a stacking of bilayers.
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Affiliation(s)
- Pariya Na Nakorn
- Institut für Biochemie, Westfälische Wilhelms-Universität Münster, Münster, Germany
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38
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Zhang G, Moore DJ, Mendelsohn R, Flach CR. Vibrational microspectroscopy and imaging of molecular composition and structure during human corneocyte maturation. J Invest Dermatol 2006; 126:1088-94. [PMID: 16514411 DOI: 10.1038/sj.jid.5700225] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The outermost region of the epidermis, the stratum corneum (SC), provides an essential barrier to water loss and protects against exogenous substances. The functional integrity of the SC depends on a complex maturation and exfoliation process, which is often perturbed in skin diseases. The maturation of corneocytes isolated from different depths in healthy human SC was investigated using infrared (IR) spectroscopic imaging and Raman microscopy. Both IR and Raman spectral quality of individual corneocytes was high and revealed depth-dependent variations in molecular composition. Spectral changes were identified as arising from alterations in the concentration of the major constituents of natural moisturizing factor (NMF), important in maintaining SC hydration. A significant decrease in the concentration of NMF was observed for corneocytes isolated from superficial compared to deeper SC layers (layer 3 vs. layer 11, respectively). An IR parameter that measures the relative NMF concentration in corneocytes is introduced. The potential role of vibrational imaging to evaluate corneocyte composition and molecular structure in the treatment of NMF-related diseases is discussed.
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Affiliation(s)
- Guojin Zhang
- Department of Chemistry, Newark College of Arts and Sciences, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA
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39
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Mendelsohn R, Flach CR, Moore DJ. Determination of molecular conformation and permeation in skin via IR spectroscopy, microscopy, and imaging. Biochim Biophys Acta 2006; 1758:923-33. [PMID: 16730643 DOI: 10.1016/j.bbamem.2006.04.009] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Revised: 02/17/2006] [Accepted: 04/11/2006] [Indexed: 11/18/2022]
Abstract
Skin tissue, in addition to its specific use in dermal research, provides an excellent model for developing the techniques of vibrational microscopy and imaging for biomedical applications. In addition to permitting characterization of various regions of skin, the relative paucity of major biological constituents in the stratum corneum (the outermost layer of skin), permits us to image, with microscopic resolution, conformational alterations and concentration variations in both the lipid and protein components. Thus we are able to monitor the effects of exogenous materials such as models for drug delivery agents (liposomes) and permeation enhancers (DMSO) on stratum corneum lipid organization and protein structure. In addition, we are able to monitor protein conformational changes in single corneocytes. The current article demonstrates these procedures, ranging from direct univariate measures of lipid chain conformational disorder, to factor analysis which permits us to image conformational differences between liposomes that have permeated through the stratum corneum from those which have remained on the surface in a reservoir outside the skin.
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Affiliation(s)
- Richard Mendelsohn
- Department of Chemistry, Newark College, Rutgers University, Newark, NJ 07102, USA.
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40
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Xiao C, Moore DJ, Rerek ME, Flach CR, Mendelsohn R. Feasibility of Tracking Phospholipid Permeation into Skin Using Infrared and Raman Microscopic Imaging. J Invest Dermatol 2005; 124:622-32. [PMID: 15737204 DOI: 10.1111/j.0022-202x.2004.23608.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The feasibility of monitoring the permeation of chain perdeuterated 1,2-dipalmitoylphosphatidylcholine (DPPC-d62) and 1-palmitoyl-d31, 2-oleoylphosphatidylcholine (P-d31OPC) vesicles into pigskin using infrared (IR) microscopic imaging and confocal Raman microscopy was demonstrated. The former technique permits the examination of the relative concentration of molecular species (e.g., endogenous and exogenous lipids and proteins) over spatial areas, approximately 1 mm, with a spatial resolution of approximately 10-12 microm. In contrast, Raman microscopy allows the confocal examination of tissue at depths up to 100 microm with a pixel size of about 2-3 microm3. Spectral signal/noise, however, is reduced from IR and significantly smaller areas are generally monitored. The permeation of the gel phase DPPC-d62 was limited to approximately 5-15 microm, whereas the liquid-crystalline phase P-d31OPC permeated to substantially greater depths (35-100 microm), at times ranging up to 24 h after application. The results are generally in accord with literature values. In addition, the state of the P-d31OPC (intact vesicles or molecularly dispersed with skin constituents) was evaluated from the spatial dependence of the deuteriopalmitate chain conformational order. Upon permeation, the chains became more ordered. The advantages and limitations of these imaging technologies are discussed.
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Affiliation(s)
- Chunhong Xiao
- Department of Chemistry, Rutgers University, Newark College of Arts and Sciences, Newark, New Jersey 07102, USA
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41
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Wang L, Cai P, Galla HJ, He H, Flach CR, Mendelsohn R. Monolayer–multilayer transitions in a lung surfactant model: IR reflection–absorption spectroscopy and atomic force microscopy. Eur Biophys J 2005; 34:243-54. [PMID: 15645307 DOI: 10.1007/s00249-004-0446-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2004] [Accepted: 10/26/2004] [Indexed: 11/29/2022]
Abstract
A hydrophobic pulmonary surfactant protein, SP-C, has been implicated in surface-associated activities thought to facilitate the work of breathing. Model surfactant films composed of lipids and SP-C display a reversible transition from a monolayer to surface-associated multilayers upon compression and expansion at the air/water (A/W) interface. The molecular-level mechanics of this process are not yet fully understood. The current work uses atomic force microscopy on Langmuir-Blodgett films to verify the formation of multilayers in a dipalmitoylphosphatidylcholine, dipalmitoylphosphatidylglycerol, cholesterol, and SP-C model system. Isotherms of SP-C-containing films are consistent with exclusion and essentially complete respreading during compression and expansion, respectively. Multilayer formation was not detected in the absence of SP-C. Most notable are the results from IR reflection-absorption spectroscopy (IRRAS) conducted at the A/W interface, where the position and intensity of the Amide I band of SP-C reveal that the predominantly helical structure changes its orientation in monolayers versus multilayers. IRRAS measurements indicate that the helix tilt angle changed from approximately 80 degrees in monolayers to a transmembrane orientation in multilayers. The results constitute the first quantitative measure of helix orientation in mixed monolayer/multilamellar domains at the A/W interface and provide insight into the molecular mechanism for SP-C-facilitated respreading of surfactant.
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Affiliation(s)
- Lin Wang
- Department of Chemistry, Newark College of Arts and Sciences, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA.
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42
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Brauner JW, Flach CR, Mendelsohn R. A Quantitative Reconstruction of the Amide I Contour in the IR Spectra of Globular Proteins: From Structure to Spectrum. J Am Chem Soc 2005; 127:100-9. [PMID: 15631459 DOI: 10.1021/ja0400685] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Amide I contours of six globular proteins of varied secondary structure content along with a peptide model for collagen and pulmonary surfactant protein C have been simulated very closely by using a modified GF matrix method. The starting point for the method uses the three-dimensional structure as obtained from the Protein Data Bank. Elements of the interactions between peptide groups (e.g., transition dipole coupling) are very sensitive to tertiary structure, thus the current formalism demonstrates that the Amide I contour may be useful for a more detailed probe of 3-D conformation that goes beyond the traditional use of this band to probe the percentages of particular elements of secondary structure. For example, postulated changes to a known structure can be tested by comparing the new simulated band to the experimental band. A number of refinements to the transition dipole interaction calculation have been made. Most of the important interactions between the C=O oscillators that define the Amide I mode appear to have been identified, including through space transition dipole coupling, through valence bond and through hydrogen bond coupling. The eigenvector matrix produced by the method permits the contribution of each peptide group to the spectrum to be precisely determined. Analysis of the results shows that the often-used structure-frequency correlations are at best approximate and at worst misleading. The subbands from helices, sheets, turns, and loops are much broader and more overlapped than has been commonly assumed. Furthermore, the traditional alpha-helical marker band may be substantially distorted in short segments. Difference spectra based on isotope editing, a technique thought capable of revealing the spectral contributions of individual peptide groups, are shown to be prone to misinterpretation.
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Affiliation(s)
- Joseph W Brauner
- Department of Chemistry, Rutgers University, Newark College of Arts and Sciences, 73 Warren Street, Newark New Jersey 07102, USA
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43
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Xu Z, Brauner JW, Flach CR, Mendelsohn R. Orientation of peptides in aqueous monolayer films. Infrared reflection-absorption spectroscopy studies of a synthetic amphipathic beta-sheet. Langmuir 2004; 20:3730-3. [PMID: 15875407 DOI: 10.1021/la0304316] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Infrared reflection-absorption spectroscopy (IRRAS) intensities of the Amide I vibration are used to develop a quantitative approach for determining the Euler angles that describe the orientation of protein beta-sheets in aqueous monolayer films. A synthetic amphipathic peptide, Val-Glu-Val-Orn-Val-Glu-Val-Orn-Val-Glu-Val-Orn-Val-OH is used as a test case. The pattern of Amide I frequencies suggests that the molecule is organized as an antiparallel beta-sheet at the air/water interface. The model used to simulate the Amide I intensities reveals that the beta-sheet has a slight preferential alignment parallel to the direction of compression; i.e., deviation from uniaxial symmetry is observed. In addition, the sheet is found to lie flat on the aqueous surface, with (presumably) the polar side chains interacting with the aqueous subphase. Limitations and advantages of the theoretical approach are discussed.
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Affiliation(s)
- Zhi Xu
- Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, USA
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44
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Xiao C, Flach CR, Marcott C, Mendelsohn R. Uncertainties in depth determination and comparison of multivariate with univariate analysis in confocal Raman studies of a laminated polymer and skin. Appl Spectrosc 2004; 58:382-389. [PMID: 15104806 DOI: 10.1366/000370204773580202] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Confocal Raman microscopy data are reported for a laminated polymer (Paramount) and for pigskin. The nature of the laminated structure of the polymer provides a useful test for evaluation of thickness distortions in confocal measurements in soft samples, which are found to be quite significant. The spatial variation in line profiles generated from univariate analyses with scores derived from factor loadings are consistent for both samples and provide distinct diagnostic markers for stratum corneum and epidermis regions of skin. Univariate analysis of the C-C stretching region of skin reveals a spatial dependence of chain conformational order. In addition, variations in keratin-containing areas of the stratum corneum are readily identified from area maps of the S-S stretching vibrations. These data indicate that confocal Raman imaging studies of molecular structure changes in particular regions of skin during pathological processes will prove quite valuable in dermatology.
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Affiliation(s)
- Chunhong Xiao
- Department of Chemistry, Rutgers University, Newark, New Jersey 07102, USA
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45
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Cai P, Flach CR, Mendelsohn R. An infrared reflection-absorption spectroscopy study of the secondary structure in (KL4)4K, a therapeutic agent for respiratory distress syndrome, in aqueous monolayers with phospholipids. Biochemistry 2003; 42:9446-52. [PMID: 12899632 DOI: 10.1021/bi030052b] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
KLLLLKLLLLKLLLLKLLLLK (KL(4)) has been suggested to mimic some aspects of the pulmonary surfactant protein SP-B and has been tested clinically as a therapeutic agent for respiratory distress syndrome in premature infants [Cochrane, C. G., and Revak, S. D. (1991) Science 254, 566-568]. It is of obvious interest to understand the mechanism of KL(4) function as a guide for design of improved therapeutic agents. Attenuated total reflection (ATR) IR measurements have indicated that KL(4) is predominantly alpha-helical with a transmembrane orientation in lipid multilayers (1), a geometry quite different from the originally proposed peripheral membrane lipid interaction. However, the lipid multilayer model required for ATR may not be the best experimental paradigm to mimic the in vivo function of KL(4). In the current experiments, IR reflection-absorption spectroscopy (IRRAS) was used to evaluate peptide secondary structure in monolayers at the air/water interface, the physical state that best approximates the alveolar lining. In contrast to the ATR-IR results, KL(4) (2.5-5 mol %) films with either DPPC or DPPC/DPPG (7/3 mol ratio) adopted an antiparallel beta-sheet structure at all surface pressures studied > or =5 mN/m, including pressures physiologically relevant for lung function (40-72 mN/m). In contrast, in DPPG/KL(4) films, the dominant conformation was the alpha-helix over the entire pressure range, a possible consequence of enhanced electrostatic interactions. IRRAS has thus provided unique molecular structure information and insight into KL(4)/lipid interaction in a physiologically relevant state. A structural model is proposed for the response of the peptide to surface pressure changes.
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Affiliation(s)
- Peng Cai
- Department of Chemistry, Newark College of Arts and Sciences, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, USA
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46
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Flach CR, Cai P, Dieudonné D, Brauner JW, Keough KMW, Stewart J, Mendelsohn R. Location of structural transitions in an isotopically labeled lung surfactant SP-B peptide by IRRAS. Biophys J 2003; 85:340-9. [PMID: 12829488 PMCID: PMC1303089 DOI: 10.1016/s0006-3495(03)74478-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Pulmonary surfactant, a lipid/protein complex that lines the air/water interface in the mammalian lung, functions to reduce the work of breathing. Surfactant protein B (SP-B) is a small, hydrophobic protein that is an essential component of this mixture. Structure-function relationships of SP-B are currently under investigation as the protein and its peptide analogs are being incorporated into surfactant replacement therapies. Knowledge of the structure of SP-B and its related peptides in bulk and monolayer phases will facilitate the design of later generation therapeutic agents. Prior infrared reflection-absorption spectroscopic studies reported notable, reversible surface pressure-induced antiparallel beta-sheet formation in a synthetic peptide derived from human SP-B, residues 9-36 (SP-B(9-36)). In the current work, infrared reflection-absorption spectroscopy is applied in conjunction with isotopic labeling to detect the site and pressure dependence of the conformational change. SP-B(9-36), synthesized with (13)C=O-labeled Ala residues in positions 26, 28, 30, and 32, shifted the beta-sheet marker band to approximately 1600 cm(-1) and thus immediately identified this structural element within the labeled region. Surface pressure-induced alterations in the relative intensities of Amide I band constituents are interpreted using a semiempirical transition dipole coupling model. In addition, electron micrographs reveal the formation of tubular myelin structures from in vitro preparations using SP-B(9-36) in place of porcine SP-B indicating that the peptide has the potential to mimic this property of the native protein.
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Affiliation(s)
- Carol R Flach
- Department of Chemistry, Newark College of Arts and Sciences, Rutgers University, Newark, New Jersey, USA.
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47
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Brauner JW, Flach CR, Xu Z, Bi X, Lewis RNAH, McElhaney RN, Gericke A, Mendelsohn R. Quantitative Functional Group Orientation in Langmuir Films by Infrared Reflection−Absorption Spectroscopy: CO Groups in Behenic Acid Methyl Ester and sn2-13C-DSPC. J Phys Chem B 2003. [DOI: 10.1021/jp030066r] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Joseph W. Brauner
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Carol R. Flach
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Zhi Xu
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Xiaohong Bi
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Ruthven N. A. H. Lewis
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Ronald N. McElhaney
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Arne Gericke
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Richard Mendelsohn
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
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48
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Bi X, Flach CR, Pérez-Gil J, Plasencia I, Andreu D, Oliveira E, Mendelsohn R. Secondary structure and lipid interactions of the N-terminal segment of pulmonary surfactant SP-C in Langmuir films: IR reflection-absorption spectroscopy and surface pressure studies. Biochemistry 2002; 41:8385-95. [PMID: 12081487 DOI: 10.1021/bi020129g] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pulmonary surfactant, a thin lipid/protein film lining mammalian lungs, functions in vivo to reduce the work of breathing and to prevent alveolar collapse. Analogues of two hydrophobic surfactant proteins, SP-B and SP-C, have been incorporated into therapeutic agents for respiratory distress syndrome, a pathological condition resulting from deficiency in surfactant. To facilitate rational design of therapeutic agents, a molecular level understanding of lipid interaction with surfactant proteins or their analogues in aqueous monolayer films is necessary. The current work uses infrared reflection-absorption spectroscopy (IRRAS) to determine peptide conformation and the effects of S-palmitoylation on the lipid interactions of a synthetic 13 residue N-terminal peptide [SP-C13(palm)(2)] of SP-C, in mixtures with 1,2-dipalmitoylphosphatidylcholine (DPPC) or 1,2-dipalmitoylphosphatidylglycerol (DPPG). Two Amide I' features, at approximately 1655 and approximately 1639 cm(-1) in the peptide IRRAS spectra, are assigned to alpha-helical peptide bonds in hydrophobic and aqueous environments, respectively. In binary DPPC/SP-C13(palm)(2) films, the proportion of hydrated/hydrophobic helix increases reversibly with surface pressure (pi), suggestive of the peptide being squeezed out from hydrophobic regions of the monolayer. No such effect was observed for DPPG/peptide monolayers, indicative of stronger, probably electrostatic, interactions. Depalmitoylation produced a weakened interaction with either phospholipid as deduced from IRRAS spectra and from pi-area isotherms. S-Palmitoylation may modulate peptide hydration and conformation in the N-terminal region of SP-C and may thus permit the peptide to remain in the film at the high surface pressures present during lung compression. The unique capability of IRRAS to detect the surface pressure dependence of protein or peptide structure/interactions in a physiologically relevant model for surfactant is clearly demonstrated.
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Affiliation(s)
- Xiaohong Bi
- Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, USA
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Mendelsohn R, Flach CR. Infrared reflection-absorption spectroscopy of lipids, peptides, and proteins in aqueous monolayers. Peptide-Lipid Interactions 2002. [DOI: 10.1016/s1063-5823(02)52005-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Bi X, Taneva S, Keough KM, Mendelsohn R, Flach CR. Thermal stability and DPPC/Ca2+ interactions of pulmonary surfactant SP-A from bulk-phase and monolayer IR spectroscopy. Biochemistry 2001; 40:13659-69. [PMID: 11695915 DOI: 10.1021/bi011188h] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Surfactant protein A (SP-A), the most abundant pulmonary surfactant protein, is implicated in multiple biological functions including surfactant homeostasis, biophysical activity, and host defense. SP-A forms ternary complexes with lipids and Ca2+ which are important for protein function. The current study uses infrared (IR) transmission spectroscopy to investigate the bulk-phase interaction between SP-A, 1,2-dipalmitoylphosphatidylcholine (DPPC), and Ca2+ ions along with IR reflection-absorption spectroscopy (IRRAS) to examine protein secondary structure and lipid orientational order in monolayer films in situ at the air/water interface. The amide I contour of SP-A reveals two features at 1653 and 1636 cm(-1) arising from the collagen-like domain and a broad feature at 1645 cm(-1) suggested to arise from the carbohydrate recognition domain (CRD). SP-A secondary structure is unchanged in lipid monolayers. Thermal denaturation of SP-A in the presence of either DPPC or Ca2+ ion reveals a sequence of events involving the initial melting of the collagen-like region, followed by formation of intermolecular extended forms. Interestingly, these spectral changes were inhibited in the ternary system, showing that the combined presence of both DPPC and Ca2+ confers a remarkable thermal stability upon SP-A. The ternary interaction was revealed by the enhanced intensity of the asymmetric carboxylate stretching vibration. The IRRAS measurements indicated that incorporation of SP-A into preformed DPPC monolayers at a surface pressure of 10 mN/m induced a decrease in the average acyl chain tilt angle from 35 degrees to 28 degrees. In contrast, little change in chain tilt was observed at surface pressures of 25 or 40 mN/m. These results are consistent with and extend the fluorescence microscopy studies of Keough and co-workers [Ruano, M. L. F., et al. (1998) Biophys. J. 74, 1101-1109] in which SP-A was suggested to accumulate at the liquid-expanded/liquid-condensed boundary. Overall these experiments reveal the remarkable stability of SP-A in diverse, biologically relevant environments.
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Affiliation(s)
- X Bi
- Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, USA
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