TY  - JOUR
A1  - Brendtke, Rico
A1  - Wiehl, Michael
A1  - Groeber, Florian
A1  - Schwarz, Thomas
A1  - Walles, Heike
A1  - Hansmann, Jan
T1  - Feasibility Study on a Microwave-Based Sensor for Measuring Hydration Level Using Human Skin Models
JF  - PLoS ONE
N2  - Tissue dehydration results in three major types of exsiccosis—hyper-, hypo-, or isonatraemia. All three types entail alterations of salt concentrations leading to impaired biochemical processes, and can finally cause severe morbidity. The aim of our study was to demonstrate the feasibility of a microwave-based sensor technology for the non-invasive measurement of the hydration status. Electromagnetic waves at high frequencies interact with molecules, especially water. Hence, if a sample contains free water molecules, this can be detected in a reflected microwave signal. To develop the sensor system, human three-dimensional skin equivalents were instituted as a standardized test platform mimicking reproducible exsiccosis scenarios. Therefore, skin equivalents with a specific hydration and density of matrix components were generated and microwave measurements were performed. Hydration-specific spectra allowed deriving the hydration state of the skin models. A further advantage of the skin equivalents was the characterization of the impact of distinct skin components on the measured signals to investigate mechanisms of signal generation. The results demonstrate the feasibility of a non-invasive microwave-based hydration sensor technology. The sensor bears potential to be integrated in a wearable medical device for personal health monitoring.
KW  - gels
KW  - microwave radiation
KW  - collagens
KW  - skin physiology
KW  - reflection
KW  - skin anatomy
KW  - epidermis
KW  - antennas
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-179934
VL  - 11
IS  - 4
ER  - 
TY  - JOUR
A1  - Groeber, Florian
A1  - Engelhardt, Lisa
A1  - Lange, Julia
A1  - Kurdyn, Szymon
A1  - Schmid, Freia F.
A1  - Rücker, Christoph
A1  - Mielke, Stephan
A1  - Walles, Heike
A1  - Hansmann, Jan
T1  - A First Vascularized Skin Equivalent as an Alternative to Animal Experimentation
JF  - ALTEX - Alternatives to Animal Experimentation
N2  - Tissue-engineered skin equivalents mimic key aspects of the human skin, and can thus be employed as wound coverage for large skin defects or as in vitro test systems as an alternative to animal models. However, current skin equivalents lack a functional vasculature limiting clinical and research applications. This study demonstrates the generation of a vascularized skin equivalent with a perfused vascular network by combining a biological vascularized scaffold (BioVaSc) based on a decellularized segment of a porcine jejunum and a tailored bioreactor system. Briefly, the BioVaSc was seeded with human fibroblasts, keratinocytes, and human microvascular endothelial cells. After 14 days at the air-liquid interface, hematoxylin & eosin and immunohistological staining revealed a specific histological architecture representative of the human dermis and epidermis including a papillary-like architecture at the dermal-epidermal-junction. The formation of the skin barrier was measured non-destructively using impedance spectroscopy. Additionally, endothelial cells lined the walls of the formed vessels that could be perfused with a physiological volume flow. Due to the presence of a complex in-vivo-like vasculature, the here shown skin equivalent has the potential for skin grafting and represents a sophisticated in vitro model for dermatological research.
KW  - alternative to animal testing
KW  - skin equivalents
KW  - tissue engineering
KW  - vascularization
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164438
VL  - 33
IS  - 4
ER  -