We report classes of electronic systems that achieve thicknesses, effective elastic moduli, bending stiffnesses, and areal mass densities matched to the epidermis. Unlike traditional wafer-based technologies, laminating such devices onto the skin leads to conformal contact and adequate adhesion based on van der Waals interactions alone, in a manner that is mechanically invisible to the user. We describe systems incorporating electrophysiological, temperature, and strain sensors, as well as transistors, light-emitting diodes, photodetectors, radio frequency inductors, capacitors, oscillators, and rectifying diodes. Solar cells and wireless coils provide options for power supply. We used this type of technology to measure electrical activity produced by the heart, brain, and skeletal muscles and show that the resulting data contain sufficient information for an unusual type of computer game controller.

Means for high-density multiparametric physiological mapping and stimulation are critically important in both basic and clinical cardiology. Current conformal electronic systems are essentially 2D sheets, which cannot cover the full epicardial surface or maintain reliable contact for chronic use without sutures or adhesives. Here we create 3D elastic membranes shaped precisely to match the epicardium of the heart via the use of 3D printing, as a platform for deformable arrays of multifunctional sensors, electronic and optoelectronic components. Such integumentary devices completely envelop the heart, in a form-fitting manner, and possess inherent elasticity, providing a mechanically stable bioti-/abiotic interface during normal cardiac cycles. Component examples range from actuators for electrical, thermal and optical stimulation, to sensors for pH, temperature and mechanical strain. The semiconductor materials include silicon, gallium arsenide and gallium nitride, co-integrated with metals, metal oxides and polymers, to provide these and other operational capabilities. Ex vivo physiological experiments demonstrate various functions and methodological possibilities for cardiac research and therapy.

We describe the use of semiconductor nanomaterials, advanced fabrication methods and unusual device designs for a class of electronics capable of integration onto the inner and outer surfaces of thin, elastomeric sheets in closed-tube geometries, specially formed for mounting on the fingertips. Multifunctional systems of this type allow electrotactile stimulation with electrode arrays multiplexed using silicon nanomembrane (Si NM) diodes, high-sensitivity strain monitoring with Si NM gauges, and tactile sensing with elastomeric capacitors. Analytical calculations and finite element modeling of the mechanics quantitatively capture the key behaviors during fabrication/assembly, mounting and use. The results provide design guidelines that highlight the importance of the NM geometry in achieving the required mechanical properties. This type of technology could be used in applications ranging from human-machine interfaces to 'instrumented' surgical gloves and many others.

There is mounting evidence that T helper (Th)17 cells and regulatory T cells (Treg) play parts in the pathogenesis of autoimmune disease. Hence, levels of these T-cell subsets in patients with alopecia areata (AA) merit investigation. Our goal was to assess Th17 and Treg levels in peripheral blood mononuclear cells (PBMC) and scalp lesions of patients with AA, correlating the findings with clinical characteristics. PBMC of 177 patients with AA (test group) and 42 healthy controls and scalp tissues of 33 patients and 15 healthy controls were collected. Levels of Th17 and Treg subsets were then determined via flow cytometry and immunohistochemical staining, correlating results in test subjects with clinical features of AA. Th17 levels were significantly higher in patients, whereas Treg levels were lower by comparison. Furthermore, Th17 levels in patients with disease of short duration or in the active phase were significantly higher, relative to their respective counterparts. Th17 levels also negatively correlated with disease duration. While Treg levels were higher in severe AA than in mild AA. Results of lesions were parallel to findings of PBMC. Our data indicates an imbalance in the immune state of patients with AA.