Multiple approaches have been described for achieving therapeutically-effective wound healing. Biological factors that induce stimulation of cells to trigger and enhance the healing process have been extensively studied, and recently, new approaches for their delivery have been the focus of a vast number of studies.
Delivery issues inherent to wound dressings include the need to maintain elevated concentrations of drug during the period of treatment, while supporting the delivery of multiple drugs over time. Using a combination of ﬂexible electronics, biomaterials, and drug delivery, a new textile-based wound dressing was recently described which supports the temporal, on-demand delivery of multiple wound-healing drugs. The work originates from the lab of Adi Khademhosseini in the Department of Medicine at Brigham and Women’s Hospital at Harvard Medical School, in collaboration with researchers from the University of Nebraska-Lincoln.
The patch system is based on functional fibers coating a hydrogel layer carrying thermoresponsive particles which are coated on a ﬂexible thread-based heater. The ﬁbers are connected to a microcontroller which provides operational power. The ﬁbers are constructed from threads coated with a layer of electrically-conductive ink and covered with a hydrogel layer of alginate /poly(ethylene glycol) diacrylate (PEGDA). The particles represent the biologically active layer, and provide temporal release of drugs and growth factors over time.
The skin patch is powered by a microcontroller that can wirelessly transfer commands from an external source such as a smartphone.
The authors tested the patch both in vitro and in vivo.
In vitro, the authors performed a scratch assay test. The premise was to mimic the cell migration during healing of the wound and to show the efﬁcacy of the healing.To do that, the authors created a scratch with a pipette over a monolayer of growing, conﬂuent keratinocytes, which were contaminated with S. aureus. This assay yielded a reduction of the “wound” by 20% over the course of 48 hours, alongside efficient migration of cells to cover the wound gap.
In vivo, the authors used db/db mice receiving the patch without VEGF and wounded mice receiving the patch with VEGF as the test subjects. These studies resulted in authors the release of VEGF from the textile patch resulted in a 3-fold higher incrase in granulation tissue deposition in the wound bed compared to controls.
The study was published in Advanced Functional Materials and can be accessed here.