An On-Site Thermoelectric Cooling Device for Cryotherapy and Control of Skin Blood Flow.

Cryotherapy involves the surface application of low temperatures to enhance the healing of soft tissue injuries. Typical devices embody a remote source of chilled water that is pumped through a circulation bladder placed on the treatment site. In contrast, the present device uses thermoelectric refrigeration modules to bring the cooling source directly to the tissue to be treated, thereby achieving significant improvements in control of therapeutic temperature while having a reduced size and weight. A prototype system was applied to test an oscillating cooling and heating protocol for efficacy in regulating skin blood perfusion in the treatment area. Data on 12 human subjects indicate that thermoelectric coolers (TECs) delivered significant and sustainable changes in perfusion for both heating (increase by (±SE) 173.0 ± 66.0%, P < 0.005) and cooling (decrease by (±SE) 57.7 ± 4.2%, P < 0.0005), thus supporting the feasibility of a TEC-based device for cryotherapy with local temperature regulation.

Instructive Conductive 3D Silk Foam-Based Bone Tissue Scaffolds Enable Electrical Stimulation of Stem Cells for Enhanced Osteogenic Differentiation.

Stimuli-responsive materials enabling the behavior of the cells that reside within them to be controlled are vital for the development of instructive tissue scaffolds for tissue engineering. Herein, we describe the preparation of conductive silk foam-based bone tissue scaffolds that enable the electrical stimulation of human mesenchymal stem cells (HMSCs) to enhance their differentiation toward osteogenic outcomes.

Electrical stimulation of human mesenchymal stem cells on biomineralized conducting polymers enhances their differentiation towards osteogenic outcomes.

Tissue scaffolds allowing the behaviour of the cells that reside on them to be controlled are of particular interest for tissue engineering. Herein we describe biomineralized conducting polymer-based bone tissue scaffolds that facilitate the electrical stimulation of human mesenchymal stem cells, resulting in enhancement of their differentiation towards osteogenic outcomes.

Conducting polymer-based multilayer films for instructive biomaterial coatings.

AIM: To demonstrate the design, fabrication and testing of conformable conducting biomaterials that encourage cell alignment. MATERIALS & METHODS: Thin conducting composite biomaterials based on multilayer films of poly(3.4-ethylenedioxythiophene) derivatives, chitosan and gelatin were prepared in a layer-by-layer fashion. Fibroblasts were observed with fluorescence microscopy and their alignment (relative to the dipping direction and direction of electrical current passed through the films) was determined using ImageJ. RESULTS: Fibroblasts adhered to and proliferated on the films. Fibroblasts aligned with the dipping direction used during film preparation and this was enhanced by a DC current. CONCLUSION: We report the preparation of conducting polymer-based films that enhance the alignment of fibroblasts on their surface which is an important feature of a variety of tissues.

Biodegradable electroactive polymers for electrochemically-triggered drug delivery.

We report biodegradable electroactive polymer (EAP)-based materials and their application as drug delivery devices. Copolymers composed of oligoaniline-based electroactive blocks linked to either polyethylene glycol or polycaprolactone blocks via ester bonds were synthesized in three steps from commercially available starting materials and isolated without the need for column chromatography. The physicochemical and electrochemical properties of the polymers were characterized with a variety of techniques. The ability of the polymers to deliver the anti-inflammatory drug dexamethasone phosphate on the application of electrochemical stimuli was studied spectroscopically. Films of the polymers were shown to be degradable and cell adhesive in vitro. Such EAP-based materials have prospects for integration in implantable fully biodegradable/bioerodible EAP-based drug delivery devices that are capable of controlling the chronopharmacology of drugs for future clinical application.

Electric field stimulation through a substrate influences Schwann cell and extracellular matrix structure.

OBJECTIVE: Electric field (EF) stimulation has been used to cue cell growth for tissue engineering applications. In this study, we explore the electrical parameters and extracellular mechanisms that elicit changes in cell behavior when stimulated through the substrate. APPROACH: Rat Schwann cell morphology was compared when exposed to EF through the media or a conductive indium tin oxide substrate. Ionic and structural effects were then analyzed on Matrigel and collagen I, respectively. MAIN RESULTS: When stimulating through media, cells had greater alignment perpendicular to the EF with higher current densities (106 mA cm(-2) at 245 mV mm(-1)), and reached maximum alignment within 8 h. Stimulation through the substrate with EF (up to 110 mV mm(-1)) did not affect Schwann cell orientation, however the EF caused extracellular matrix (ECM) coatings on substrates to peel away, suggesting EF can physically change the ECM. Applying alternating current (ac) 2-1000 Hz signals through the media or substrate both caused cells to flatten and protrude many processes, without preferential alignment. Matrigel exposed to a substrate EF of 10 mV mm(-1) for 2 h had a greater calcium concentration near the cathode, but quickly dissipated when the EF was removed. Schwann cells seeded 7 d after gels were exposed to substrate EF still aligned perpendicular to the EF direction. Microscopy of collagen I exposed to substrate EF shows alignment and bundling of fibrils. SIGNIFICANCE: These findings demonstrate EF exposure can control Schwann cell alignment and morphology, change ECM bulk/surface architecture, and align ECM structures.