An elastic second skin

We report the synthesis and application of an elastic, wearable crosslinked polymer layer (XPL) that mimics the properties of normal, youthful skin. XPL is made of a tunable polysiloxane-based material that can be engineered with specific elasticity, contractility, adhesion, tensile strength and occlusivity. XPL can be topically applied, rapidly curing at the skin interface without the need for heat- or light-mediated activation. In a pilot human study, we examined the performance of a prototype XPL that has a tensile modulus matching normal skin responses at low strain (<40%), and that withstands elongations exceeding 250%, elastically recoiling with minimal strain-energy loss on repeated deformation. The application of XPL to the herniated lower eyelid fat pads of 12 subjects resulted in an average 2-grade decrease in herniation appearance in a 5-point severity scale. The XPL platform may offer advanced solutions to compromised skin barrier function, pharmaceutical delivery and wound dressings

Fractional Skin Harvesting: Autologous Skin Grafting without Donor-site Morbidity

Background: Conventional autologous skin grafts are associated with significant donor-site morbidity. This study was conducted to determine feasibility, safety, and efficacy of a new strategy for skin grafting based on harvesting small columns of full-thickness skin with minimal donor-site morbidity. Methods: The swine model was used for this study. Hundreds of full-thickness columns of skin tissue (~700 µm diameter) were harvested using a custom-made harvesting device, and then applied directly to excisional skin wounds. Healing in donor and graft sites was evaluated over 3 months by digital photographic measurement of wound size and blinded, computer-aided evaluation of histological features and compared with control wounds that healed by secondary intention or with conventional split-thickness skin grafts (STSG). Results: After harvesting hundreds of skin columns, the donor sites healed rapidly without scarring. These sites reepithelialized within days and were grossly and histologically indistinguishable from normal skin within 7 weeks. By contrast, STSG donor sites required 2 weeks for reepithelialization and retained scar-like characteristics in epidermal and dermal architecture throughout the experiment. Wounds grafted with skin columns resulted in accelerated reepithelialization compared with ungrafted wounds while avoiding the “fish-net” patterning caused by STSG. Conclusion: Full-thickness columns of skin can be harvested in large quantities with negligible long-term donor-site morbidity, and these columns can be applied directly to skin wounds to enhance wound healing

A micro-sterile inflammation array as an adjuvant for influenza vaccines

There is an urgent need of adjuvants for cutaneous vaccination. Here we report that micro-sterile inflammation induced at inoculation sites can augment immune responses to influenza vaccines in animal models. The inoculation site is briefly illuminated with a handheld, non-ablative fractional laser before the vaccine is intradermally administered, which creates an array of self-healing microthermal zones (MTZs) in the skin. The dying cells in the MTZs send “danger” signals that attract a large number of antigen-presenting cells, in particular, plasmacytoid dendritic cells (pDCs) around each MTZ forming a micro-sterile inflammation array. A pivotal role for pDCs in the adjuvanticity is ascertained by significant abrogation of the immunity after systemic depletion of pDCs, local application of a TNF-α inhibitor, or null mutation of IFN regulatory factor7 (IRF7). In contrast to conventional adjuvants that cause persistent inflammation and skin lesions, micro-sterile inflammation enhances efficacy of influenza vaccines, yet with diminished adverse effects

Reconstitution of full‐thickness skin by microcolumn grafting

Abstract In addition to providing a physical barrier, skin also serves a diverse range of physiological functions through different specialized resident cell types/structures, including melanocytes (pigmentation and protection against ultraviolet radiation), Langerhans cells (adaptive immunity), fibroblasts (maintaining extracellular matrix, paracrine regulation of keratinocytes), sweat glands (thermoregulation) and hair follicles (hair growth, sensation and a stem cell reservoir). Restoration of these functional elements has been a long‐standing challenge in efforts to engineer skin tissue, while autologous skin grafting is limited by the scarcity of donor site skin and morbidity caused by skin harvesting. We demonstrate an alternative approach of harvesting and then implanting μm‐scale, full‐thickness columns of human skin tissue, which can be removed from a donor site with minimal morbidity and no scarring. Fresh human skin microcolumns were used to reconstitute skin in wounds on immunodeficient mice. The restored skin recapitulated many key features of normal human skin tissue, including epidermal architecture, diverse skin cell populations, adnexal structures and sweat production in response to cholinergic stimulation. These promising preclinical results suggest that harvesting and grafting of microcolumns may be useful for reconstituting fully functional skin in human wounds, without donor site morbidity. © 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd

Biomedical optics centers: forty years of multidisciplinary clinical translation for improving human health

Despite widespread government and public interest, there are significant barriers to translating basic science discoveries into clinical practice. Biophotonics and biomedical optics technologies can be used to overcome many of these hurdles, due, in part, to offering new portable, bedside, and accessible devices. The current JBO special issue highlights promising activities and examples of translational biophotonics from leading laboratories around the world. We identify common essential features of successful clinical translation by examining the origins and activities of three major international academic affiliated centers with beginnings traceable to the mid-late 1970s: The Wellman Center for Photomedicine (Mass General Hospital, USA), the Beckman Laser Institute and Medical Clinic (University of California, Irvine, USA), and the Medical Laser Center Lübeck at the University of Lübeck, Germany. Major factors driving the success of these programs include visionary founders and leadership, multidisciplinary research and training activities in light-based therapies and diagnostics, diverse funding portfolios, and a thriving entrepreneurial culture that tolerates risk. We provide a brief review of how these three programs emerged and highlight critical phases and lessons learned. Based on these observations, we identify pathways for encouraging the growth and formation of similar programs in order to more rapidly and effectively expand the impact of biophotonics and biomedical optics on human health

Transdermal microconduits by microscission for drug delivery and sample acquisition

BACKGROUND: Painless, rapid, controlled, minimally invasive molecular transport across human skin for drug delivery and analyte acquisition is of widespread interest. Creation of microconduits through the stratum corneum and epidermis is achieved by stochastic scissioning events localized to typically 250 μm diameter areas of human skin in vivo. METHODS: Microscissioning is achieved by a limited flux of accelerated gas: 25 μm inert particles passing through the aperture in a mask held against the stratum corneum. The particles scize (cut) tissue, which is removed by the gas flow with the sensation of a gentle stream of air against the skin. The resulting microconduit is fully open and may be between 50 and 200 μm deep. RESULTS: In vivo adult human tests show that microconduits reduce the electrical impedance between two ECG electrodes from approximately 4,000 Ω to 500 Ω. Drug delivery has been demonstrated in vivo by applying lidocaine to a microconduit from a cotton swab. Sharp point probing demonstrated full anaesthesia around the site within three minutes. Topical application without the microconduit required approximately 1.5 hours. Approximately 180 μm deep microconduits in vivo yielded blood sample volumes of several μl, with a faint pricking sensation as blood enters tissue. Blood glucose measurements were taken with two commercial monitoring systems. Microconduits are invisible to the unaided eye, developing a slight erythematous macule that disappears over days. CONCLUSION: Microscissioned microconduits may provide a minimally invasive basis for delivery of any size molecule, and for extraction of interstitial fluid and blood samples. Such microconduits reduce through-skin electrical impedance, have controllable diameter and depth, are fully open and, after healing, no foreign bodies were visible using through-skin confocal microscopy. In subjects to date, microscissioning is painless and rapid

Evidence-Based Consensus on the clinical application of Photobiomodulation

BackgroundThere is a lack of evidence-based consensus to assist clinicians in using photobiomodulation (PBM).ObjectiveTo create a consensus on the safe and effective use of PBM.MethodsA systematic literature review of Embase and MEDLINE was conducted in June 2022 to identify publications reporting research on PBM. An international multidisciplinary panel was convened to draft recommendations informed by the systematic search; they were refined through 2 rounds of Delphi survey, 2 consensus meetings, and iterative review by all panelists until unanimous consensus was achieved.ResultsA multidisciplinary panel of experts (n = 21) was assembled based on publication history. The key findings that informed the consensus developed by the expert panel were as follows: PBM is a safe treatment modality for adult patients and red light PBM does not induce DNA damage. PBM is an effective treatment option for peripheral neuropathy, androgenic alopecia, wound ulcers due to multiple etiologies, decubitus ulcers, pain attributed to diabetic foot ulcers, and acute radiation dermatitis.ConclusionThe systematic literature search and structured Delphi consensus approach culminated in an evidence-based clinical practice guideline for safe and effective use of PBM in medical and aesthetic applications. Future research will further bolster our understanding of this evolving noninvasive technique