An Adhesive Patch-Based Skin Biopsy Device for Molecular Diagnostics and Skin Microbiome Studies
October 2017 | Volume 16 | Issue 10 | Original Article | 979 | Copyright © October 2017
Zuxu Yao PhD,a Ronald Moy MD,b Talisha Allen BS,a and Burkhard Jansen MDa
aDermTech Incorporated, 11099 N. Torrey Pines Road, Suite 100, La Jolla, CA bRodeoDerm Moy Fincher Chips, 421 North Rodeo Drive, Beverly Hills, CA
Abstract
INTRODUCTION: A number of diagnoses in clinical dermatology are currently histopathologically confirmed and this image recognition–based confirmation generally requires surgical biopsies. The increasing ability of molecular pathology to corroborate or correct a clinical diagnosis based on objective gene expression, mutation analysis, or molecular microbiome data is on the horizon and would be further supported by a tool or procedure to collect samples non-invasively. This study characterizes such a tool in form of a ‘bladeless’ adhesive patch-based skin biopsy device.
METHODS: The performance of this device was evaluated through a variety of complementary technologies including assessment of sample biomass, electron microscopy demonstrating the harvesting of layers of epidermal tissue, and isolation of RNA and DNA from epidermal skin samples. Samples were obtained by application of adhesive patches to the anatomical area of interest.
RESULTS: Biomass assessment demonstrated collection of approximately 0.3mg of skin tissue per adhesive patch and electron microscopy confirmed the nature of the harvested epidermal skin tissue. The obtained tissue samples are stored in a stable fashion on adhesive patches over a wide range of temperatures (-80oC to +60oC) and for extended periods of time (7 days or more). Total human RNA, human genomic DNA and microbiome DNA yields were 23.35 + 15.75ng, 27.72 + 20.71ng and 576.2 + 376.8pg, respectively, in skin samples obtained from combining 4 full patches collected non-invasively from the forehead of healthy volunteers.
DISCUSSION: The adhesive patch skin sampling procedure is well tolerated and provides robust means to obtain skin tissue, RNA, DNA, and microbiome samples without involving surgical biopsies. The non-invasively obtained skin samples can be shipped cost effectively at ambient temperature by mail or standard courier service, and are suitable for a variety of molecular analyses of the skin microbiome as well as of keratinocytes, T cells, dendritic cells, melanocytes, and other skin cells involved in the pathology of various skin conditions and conditions where the skin can serve as a surrogate target organ.
J Drugs Dermatol. 2017;16(10):979-986.
INTRODUCTION
Frequently, obtaining high quality tissue samples to confirm clinical diagnoses is an integral part of selecting appropriate treatment options or assessing treatment outcome. While most tissue samples are still collected through surgical biopsy, there is a growing trend towards minimally invasive or ideally non-invasive approaches wherever possible without compromising the required quantity and quality of the samples obtained.1 While micro-needle and adhesive patch based strategies appear to fit this paradigm, only the latter is truly non-invasive. This work focuses on the detailed characterization of such an adhesive patch-based device termed the Adhesive Patch-Based Skin Biopsy (APSB, DermTech, La Jolla, CA) Kit. The APSB kit contains a simple trifold with 4 circular adhesive patches, each 19mm in diameter, as the main harvesting device. When applied to selected skin areas or skin lesions, each adhesive patch collects a thin layer of epidermal stratum corneum tissue carrying genetic information not only from keratinocytes, but also from melanocytes, basal cells, T-cells, dendritic cells, and other skin cells. The APSB device platform can be used to collect skin tissue from all anatomical locations except from palms of hands, soles of feet, and mucous membranes.2,3,4 Total RNA of quality sufficient for a variety of molecular analyses of pigmented lesions and inflammatory skin conditions using quantitative reverse transcription-PCR (RT-qPCR), microarray-based gene expression studies, and RNA sequencing has been demonstrated.2,5,6,7,8, and unpublished data The entire tissue collection process with adhesive patches is completely non-invasive when 4 patches of skin tissues are collected from one skin area of interest; combining the material from the 4 patches provides suf cient tissue for most applications in dermatology including a commercial gene expression-based test supporting clinicians in their efforts to accurately diagnose melanoma.3,6,7,9 While previous studies focused on using the platform for RNA-based gene expression analyses, the platform also lends itself to analyses of human genomic DNA (gDNA) from skin samples and to skin microbiome analyses of co-collected samples. This study characterizes the full utility of the platform for DNA, RNA,
