Stephan Bielfeldt

Stephan Bielfeldt
proDERM Institute for Applied Dermatological Research · Research

Director Science and Innovation

About

90
Publications
71,194
Reads
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1,226
Citations
Citations since 2017
37 Research Items
719 Citations
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2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
Introduction
Stephan Bielfeldt has more than 25 years of working experience in the field of dermatological research. His main working fields are the development in vivo test methods, skin physiology and bioengineering. He has a specific expertise in sunscreen testing and in vivo Raman spectroscopy. Stephan has worked in, or is a member of, several societies : Technical expert for ISO. Member of the DGK working groups Sun Protection and Skin Care. Member of the Society for Dermopharmacy (GD).
Additional affiliations
July 2001 - present
proDERM Institute for Applied Dermatological Research
Position
  • Director Research

Publications

Publications (90)
Article
Objective: Tape stripping is an often-used minimally invasive method to investigate the skin penetration of a substance. In recent years, however, the suitability of confocal Raman spectroscopy (CRS) as a non-invasive method of non-destructive examination of the skin has become increasingly apparent. In this study, we compared invasion and depleti...
Article
Full-text available
The study of human skin represents an important area of research and development in dermatology, toxicology, pharmacology and cosmetology, in order to assess the effects of exogenous agents, their interaction, their absorption mechanism, and/or their toxicity towards the different cutaneous structures. The processes can be parameterised by mathemat...
Article
Full-text available
The study of human skin represents an important area of research and development in dermatology, toxicology, pharmacology and cosmetology, in order to assess the effects of exogenous agents, their interaction, their absorption mechanism, and/or their toxicity towards the different cutaneous structures. The processes can be parameterised by mathemat...
Article
Background: The purpose of this pilot study was to provide information about the washout-dependent depletion of important skin components in the horny layer of the scalp. They were taken as markers for scalp drying effects of cosmetic cleansing products and were measured directly in vivo. Method: In vivo confocal Raman spectroscopy was used to m...
Article
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As new biophysical methods become available to the skin researcher it is important to understand the type of information that they are capable of measuring, and how it relates to consumer perception of topical moisturizing products. The aim of the work presented here was to understand what dry skin imaging can reveal about the skin and subject feed...
Article
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As new biophysical methods become available to the skin researcher, it is important to understand the type of information that they are capable of measuring, and how it relates to consumer perception of topical moisturizing products. This work was aimed at understanding how two-dimensional (2D) skin hydration mapping can be used to describe skin pr...
Article
Diclofenac is non-steroidal anti-inflammatory drug (NSAID) with widespread usage as a topical treatment for relief of pain and inflammation in soft-tissue injuries. While the permeation mechanisms of topically applied diclofenac are well documented, the fate of residual diclofenac not retained at the site of pain following subsequent hand-washing i...
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Background Long-term use of cigarettes can result in localised staining and aging of smokers’ skin. The use of tobacco heating products (THPs) and electronic cigarettes (ECs) has grown on a global scale; however, the long-term effect of these products’ aerosols on consumers’ skin is unknown. This pilot clinical study aimed to determine whether THP...
Chapter
Effective skin protection of consumers by sunscreens can only be achieved when meaningful and reliable test methods are available to objectively measure the protection of sunscreen products. Quantitative, scientifically sound, and valid methods to detect UVB and UVA light protection as well as methods to assess sunscreen substantivity to water are...
Poster
BACKGROUND: Current global trends and increasing consumer needs demand superior cosmetic product efficacies, requiring a constant evolution of test designs for product evaluation. Dexpanthenol (DEX) is broadly used for decades as ingredient in various cosmetic applications and thereby known for several proven functions [1], like increasing skin hyd...
Article
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Background Outdoor workers (OW) are highly exposed to solar ultraviolet radiation (UVR) and thus at increased risk for developing skin cancer. An essential part of an overall strategy to reduce workplace UVR-exposure to OW’s skin is the usage of sunscreens. However, compliance with regular sunscreen usage seems to be low, as products are usually de...
Article
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Background Skin damage arising from pollutants in gaseous and particulate matter forms is mainly mediated by oxidative stress. The pollutants directly or indirectly generate free radicals on and in the skin, leading, for example, to MMP up-regulation and damage of collagen fibers. Antioxidants and chelators are used in anti-pollution cosmetics to r...
Article
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IntroductionAntivirals and occlusive lip patches are key treatments for cold sores. Additional therapeutic options, and validated methods to evaluate these, are needed.Methods This exploratory, double-blind, single-center study aimed to evaluate a novel lip patch containing the antiviral aciclovir (ACV) using noninvasive methods for measuring cold...
Article
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Background: Xerostomia is associated with several diseases and is a side effect of certain drugs, resulting from reduced saliva secretion. Often, aged and sometimes younger people suffer from (idiopathic) xerostomia. Chewing gum and sucking pastilles may relieve symptoms of xerostomia by increasing the salivary flow rate due to the mechanical effe...
Article
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Background Topical moisturizing products are widely used to alleviate the problems associated with xerotic skin. Their use affects many properties of the stratum corneum (SC) in a complex and interrelated manner. The range of measurement techniques available to the researcher has increased in recent years. However, few studies have looked for corre...
Article
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Objective: Skin health, skin appearance and skin beauty are influenced by collagen composition of the dermis. Natural aging affects the structural integrity of the collagen network, resulting in drier skin, wrinkle formation and reduced skin elasticity. Orally ingested hydrolyzed collagen reaches the skin tissue and exerts beneficial effects on hum...
Article
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Objective The development of dry skin is a complex process, with a wide variety of factors each playing different roles in its evolution. Given this, it is important when designing a formulation to tackle dry skin that these varied aspects of skin behaviour are addressed. Presented here are the results of a 3 week moisturization study carried out o...
Article
Background In vivo confocal Raman spectroscopy (CRS) revealed a clear correlation of age and dermal water content, indicating increasing water content of the dermis with increasing age. This enhancement of water has been interpreted as an age‐dependent depletion, of proteins, mainly of collagen. Chronical sun exposure is known to destroy the collag...
Article
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Zusammenfassung: Externa mit 5 % Dexpanthenol werden vielfach zur Behandlung kleinerer Wunden und zur Wiederherstellung der epidermalen Barriere bei Patienten mit empfindlicher Haut eingesetzt. Allerdings liegen bis heute nur wenige kontrollierte Studien vor, die den positiven Effekt von Dexpanthenol auf die menschliche Haut belegen. In dieser rand...
Article
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Cellulite occurs in females and is a common condition of altered connective tissue matrix and increased adipogenicity with visible dimples and orange‐peel appearance on the skins surface. Whilst advancements in methods continue to help our understanding, attempts to correct the appearance of cellulite topically have yielded limited success. Various...
Article
Full-text available
Cellulite occurs in females and is a common condition of altered connective tissue matrix and increased adipogenicity with visible dimples and orange‐peel appearance on the skins surface. Whilst advancements in methods continue to help our understanding, attempts to correct the appearance of cellulite topically have yielded limited success. Various...
Article
The purpose of this randomized, placebo-controlled, triple-blind trial on 60 healthy female volunteers was to assess the cosmetic effects on skin quality of a food supplement containing special collagen peptides together with acerola extract, vitamin C, vitamin E, biotin, and zinc after an intake of 12 weeks (Elasten®, QUIRIS Healthcare, Germany)....
Article
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Background/aim: It was the aim to establish and validate in vivo confocal Raman spectroscopy for characterization of the lip barrier in conjunction with transepidermal water loss (TEWL) and skin capacitance assessments. For the first time in vivo, barrier-relevant components of the lip (derived, natural moisturizing factors (NMFs) and ceramides ar...
Article
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Objective Lip treatment products often incorporate oils and waxes in their formulations, and a desired outcome of their use is to prevent lip dryness and roughness as well as help to repair this condition. The objective of this study was to combine confocal Raman spectroscopy with skin capacitance (corneometry) and transepidermal water loss (closed...
Article
Full-text available
Although a natural function of the skin, perspiration and the odor it produces is considered offensive in many cultures, and consequently products addressing this problem are in high demand. Antiperspirants and most deodorants are normally formulated with aluminum salts. However concerns over environmental safety, health and wellbeing are driving i...
Article
Background/Aim The scope of this study was to utilize confocal Raman spectroscopy in the evaluation of the degree of non‐penetration into the viable skin layers of a paraffin and petrolatum‐based product for use in the intimate areas of the skin. The formulation was purposely designed with properties to prevent undesirable skin penetration. Method...
Article
Objectives: This randomized, examiner-blind, crossover clinical study compared the plaque removal efficacy of three experimental toothpastes containing 20%, 35%, and 50% w/w sodium bicarbonate (NaHCO3) with commercial toothpastes containing 67% and 0% w/w NaHCO3 (positive and negative controls, respectively). Methods: Fifty-six adults with a mea...
Article
Full-text available
Objective Two studies were designed to evaluate the potential cosmetic benefit of a biomimetic, niacinamide‐containing moisturising cream for the first time in humans. Methods In both studies, healthy women were randomised to use two treatments, one for the left side of the body and one for the right, from three options: the test cream, a positive...
Article
In vitro standard methods are available and accepted worldwide to assess UVA protection of sunscreen products. Though, harmonisation of methods has made progress in the last decade, still two differing methods - one by FDA the other by ISO - are in use. In a multicentre study including 9 centres in Germany, 4 different commercial sunscreen products...
Poster
Investigation on the aged epidermal barrier function (pH, hydration, TEWL) and lipid bilayer (lipid lamellae, lipid ratio, FFA, CERs, CHOL).
Article
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With the advancement of skin research today's consumer has increased access to an informed understanding of aging skin and its appendages, together with a plethora of targeted products to meet such needs. In recent years increased legislative demands for quality evidential claims support has led not only to the development and validation of clinica...
Article
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Objective The objective of this randomized clinical study was to assess the onset time of the whitening effect of a combined use of a nonabrasive, activator-containing toothpaste and a light emitting diode (LED) device, compared to that of the toothpaste alone. Materials and Methods A nonabrasive, activator-containing toothpaste was used twice dai...
Article
Full-text available
Of all the natural functions of the skin, perspiration and its odorous consequences is one of the most lucrative challenges of the cosmetic industry, especially due to its social impact . Body odor and perspiration is deemed offensive in most cultures and cosmetic products to control this phenomenon are in high demand. The reduction of sweat and it...
Article
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The normal process of skin tissue repair following injury invariably results in visual scarring. It is well known that topical treatment with hydrophobic cosmetics high in silicone and mineral oil content can improve the appearance of scars as well as stretch marks or striae. However given lifestyle preferences of many cosmetic consumers towards na...
Article
Objective: The normal process of skin tissue repair following injury invariably results in visual scarring. It is known that topical treatment with hydrophobic cosmetics high in silicone and mineral oil content can improve the appearance of scars and striae. Given lifestyle preferences of many cosmetic consumers towards so-called natural treatment...
Article
Objective: Xerosis is a serious problem among the very old. It is a dermatological challenge caused by significant alterations in stratum corneum (SC) function and structure. Two negative changes in aged skin are: (i) the enhanced skin surface pH and (ii) the altered SC lipid content, composition and ordering. Methods: Therefore, we investigated...
Article
Purpose: Two studies were conducted with a new topical panthenol-containing emollient (NTP-CE) to investigate the skin-moisturizing effect in healthy adults and tolerability in healthy infants. Methods: In Study 1 (N = 44), a single skin application of NTP-CE was performed followed by a 4-week twice-daily application. Skin hydration and stratum...
Article
Background: The healing of wounds has always provided challenges for the medical community whether chronic or acute. Understanding the processes which enable wounds to heal is primarily carried out by the use of models, in vitro, animal and human. It is generally accepted that the use of human models offers the best opportunity to understand the f...
Article
Purpose: Two randomized, intra-individual comparison studies were performed in healthy subjects to evaluate the skin moisturization and barrier restoration potential of a new topical panthenol-containing emollient (NTP-CE) (Study 1), and its effect on skin microflora (Study 2). Methods: In study 1 (N = 23), two skin areas, one challenged with 0....
Article
Color cosmetics like mascara, make-up and lipstick are promoted with claims like "long-lasting", "high covering power" or "improve attractiveness". Makeup, foundations and powder products further are claimed to improve the evenness of the skin or reduce the visibility of wrinkles. Especially subjective parameters like radiance of facial skin have g...
Article
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The impact of increasing age on body odor has become an important issue as our understanding of underlying skin changes in older people has increased. Therefore, cosmetic skin products especially for the needs of the elderly are of growing importance. This randomized single-blind crossover study assessed the deodorizing efficacy of two cosmetic pro...
Article
This study evaluated skin tolerance and other properties relating to wear time, such as conformability and comfort, pain on dressing removal, adhesion and premature detachment, of four advanced hydrated dressings applied to the knees and elbows of 22 healthy volunteers over a fixed five-day period. The dressings all incorporate silicone-based adhes...
Article
Background: The aim of this study was to evaluate the efficacy of a new topical low molecular nano-hyaluronic acid preparation in treating wrinkles, skin hydration, and skin elasticity in humans. Methods: Thirty-three women with an average age of 45.2 were studied for a period of eight weeks to measure the anti-wrinkle efficacy of a new nano-hya...
Article
The need for emollient therapy is evident from the wide incidence of dry skin within the population. There is, however, little knowledge about the effectiveness of different emollients in their ability to moisturize the skin. This study examined the efficacy of six different emollient products in a volunteer study that measured the following parame...
Article
Thickness measurement of the outermost layer of the skin, the stratum corneum (SC), is essential for in-vivo measurement of the cutaneous bioavailability of topically applied drugs and cosmetics. Our aim was to compare SC thickness calculated from confocal Raman spectroscopy (CRS) data with results of SC thickness based on confocal laser scanning m...
Article
It is well established that decorative cosmetics can enhance female facial attractiveness. In this study, we investigated the effects of a cleanser and a decent foundation on attractiveness of female faces. Comparative rating of a set of facial photographs by a group of lay persons revealed that the cleansing product was significantly reducing the...
Article
Scars are well known to have a stratum corneum that is malfunctional. Increases in transepidermal water loss and decreases in stratum corneum capacitance and conductance have been reported. Occlusion therapy is a well-known route to improving the signs and symptoms of scarring. Until recently that has been assumed to be totally pressure related. Ho...
Article
Synopsis While sun protection factor (SPF) and UVA protection are the most important determinants of a cosmetic sunscreen product, water resistance is the third important feature. The Colipa in vivo method is the internationally accepted standard method to assess water resistance. It is time-consuming and expensive. A screening method to quickly pr...
Article
Background: Atopic dermatitis (AD) is characterized by barrier abnormalities, including insufficient ceramides in the stratum corneum (SC). Objective: To measure the effects of a new moisturizer (CRM) containing a ceramide precursor in improving skin barrier function in patients with controlled atopic dermatitis. Methods: In this randomized, intra-...
Article
Chronic wounds require frequent dressing changes. Adhesive dressings used for this indication can be damaging to the stratum corneum, particularly in the elderly where the skin tends to be thinner. Understanding the level of damage caused by dressing removal can aid dressing selection. This study used a novel methodology that applied a stain to the...
Article
Background: Skin stripping and impairment of the skin's function as a barrier are adverse effects that can be a consequence of the adhesives in wound dressings. Aim: To determine the best performing wound dressing in terms of skin protection without trauma. Method: Healthy volunteers had Mepitel® Film (Mölnlycke Health Care), Tegaderm® (3M®) and Du...
Article
This study looks at six different modern wound dressings to investigate how likely they are to cause skin stripping and impairment of the skin's barrier function. Healthy volunteers had each dressing applied, removed and reapplied to the skin on their back over the study period of 15 days. Skin barrier function was investigated using the amount of...
Article
Full-text available
Non invasive in vivo methods are presented to assess age dependent changes in the different layers of the skin. Measurement of epidermal thickness parameters and papillary index by use of confocal reflectance microscopy are explained as well as the count of capillary loops, a parameter to assess age dependent skin nutrition. To assess photo aging o...
Article
The aim of this study was to evaluate different urea-containing cosmetic preparations designed for foot care regarding skin occlusion. The primary aim was therefore to screen the short-term transepidermal water loss (TEWL) as a parameter for skin barrier function and skin occlusion and to characterize the relative role of the vehicle, i.e. cream or...
Article
In the past, several attempts have been made to develop in vitro methods for determining protection against UV radiation. To date however, there is no broadly accepted method. Various known and unknown parameters influence the transmission measurements of scattering films, such as the multifaceted compositions of sunscreens, the technical limitatio...
Article
Full-text available
IFSCC Magazine, 12 (2009) (1) 9–15 Measurement of water concentration profiles across living human skin by confocal Raman spectroscopy has developed into a powerful tool for a better understanding of distribution and function of water in the epidermis. From the water profile across the epidermis the border between stratum corneum and stratum granul...
Article
Full-text available
Background: Considerable thought has been given to the development of dressings and adhesives for use on chronic wounds. Dressings and adhesives used on acute (surgical/traumatic) wounds, however, have not had the same level of scrutiny regarding the skin damage that may be incurred on removal, particularly as the dressings are often removed after...
Article
Sunscreen efficacy is currently evaluated by the estimation of the sun protection factor (SPF). Our objective was to determine the role of the p53 labeling index in assessing the effectiveness of a sunscreen in the prevention of UV-induced DNA damage. A broad-spectrum sunscreen (SPF15) was applied to two of four test areas on the backs of 20 volunt...
Article
Background: The majority of women suffer from the unattractive sight of dimpling skin on the thighs and buttocks, globally known as cellulite. Cellulite can be regarded as the most investigated non-disease, because, from the cosmetic viewpoint, most women desire a reduction in cellulite severity. Despite investigations made, cellulite is still not...
Article
Full-text available
Background: Adhesive skin contact layers can cause trauma and pain upon removal. Aims: To compare two adhesive foam dressings, Allevyn ® Adhesive and Mepilex ® Border, in terms of the peel force required to remove them and any trauma and pain caused on removal. Methods: Strips of the dressings were applied to 22 healthy volunteers and were removed...
Article
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Background/aims: In moist intertriginous regions, such as the armpit, the pH value is physiologically higher than in other skin regions. The regulation of the axillary pH-value was examined in an open study with 48 subjects in three groups with n=16 each. Methods: In the first 10 days (run-in) the subjects received a standard treatment in the axill...
Article
Full-text available
The efficacy of antiperspirants is a current topic among the developers of cosmetic products. According to the Food and Drug Administration (FDA) for the US market, efficacy testing performed in the axilla of human volunteers is mandatory. Another method is yet available, which enables comparison of more than one antiperspirant formula in a single...
Article
Melasma is a common pigmentation disorder having considerable effect on patients' emotional and psychological well-being. Assessment of efficacy and tolerability of a new face care product for the targeted spot treatment of darker pigmented areas in subjects with melasma and evaluation of effects on patients' quality of life. Twenty subjects with m...
Article
In the field of consumer-used cosmetics for hair removal and hair growth reduction, there is a need for improved quantitative methods to enable the evaluation of efficacy and claim support. Optimized study designs and investigated endpoints are lacking to compare the efficacy of standard methods, like shaving or plucking, with new methods and produ...
Article
Full-text available
It is often debated that the protection against solar-induced erythema under real conditions is dependent upon the amount of sunscreen applied. It is believed that when too little is applied a lower sun protection than indicated on the label will result. The aim of this study was to quantify this effect. In this multicenter study, the influence of...
Article
Full-text available
Claim support for cosmetic products has to be based on scientific evidence. In cases where optical parameters of the skin have to be assessed, sophisticated image analysis techniques are paramount. This does not mean that only computerized image analysis leads to scientifically sound results. When used correctly the human eye is also a marvelous im...
Article
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Hair loss, hair thinning, poorly growing hair and powerless or dull hair are common complaints in clinical dermatology. There is a need for products, which support the hair growing process and control some of the disturbances in the hair cycle dynamics. In context of a randomised, placebo-controlled clinical trial efficacy of a fenugreek seeds cont...
Article
The purpose of our studies was to verify efficacy and skin compatibility of a medical face care system containing 2% lactic acid (LA) as active ingredient in a specially designed vehicle (Follicle Targeting System) in adult subjects with mild acne vulgaris. The first study (46 patients) demonstrated superiority of 2% LA in comparison to 2% salicyli...
Article
A multicentre study for measuring skin hydration with 349 volunteers was carried out in six different laboratories. The purpose of the study was to investigate physical-, physiological- and product-dependent parameters of three test emulsions (base, base + moisturizer and base + moisturizer + lipids) in a double-blind study. A comparison between an...
Article
A test panel of 67 female subjects with dry skin was investigated. 32 of these panelists had an atopic diathesis. The subjects applied Menalind derm Pflegecreme and Menalind derm Pflegelotion for 14 days on defined test areas on the volar forearms. Skin hydratization, transepidermal water loss and skin surface lipids were measured and a clinical as...
Article
Treatment with a self-adhesive hydroactive polyurethane dressing (Cutinova thin, Beiersdorf AG, Hamburg, Germany) applied over a period of eight weeks has been shown to have a beneficial effect on hypertrophic scars. However, the use of such dressings during the daytime on visible parts of the body is often problematic and might lead to reduced com...
Article
Dermal and mucosal tolerance of antiseptic liquid soaps which are used frequently in the health care setting is a very important quality in oder to avoid occupational irritative dermatitis. Stellisept® scrub, a new antiseptic liquid soap based on undecylenamidopropyltrimonium methosulphate and 2-phenoxyethanol, was investigated in an in vitro test...
Article
Preparations containing 5 % Dexpanthenol are frequently used for the treatment of minor wounds and to stimulate the regeneration of the epidermal barrier in patients with sensitive skin. However, there are few standardised, controlled studies that validate the positive effect of dexpanthenol on human skin in vivo. In this randomised, placebo-contro...
Chapter
Die Bedeutung des kosmetischen Sonnenschutzes hat in den letzten Jahren stark zugenommen. Das liegt zum einen an den global gestiegenen Hautkrebsraten, zum anderen an dem in der Öffentlichkeit stark diskutierten Abbau des Ozonschildes in der Atmosphäre.