Low-voltage organic field-effect transistors (OFETs) promise for low power consumption logic circuits. To enhance the efficiency of the logic circuits, the control of the threshold voltage of the transistors are based on is crucial. We report the systematic control of the threshold voltage of electrolyte-gated OFETs by using various gate metals. The influence of the work function of the metal is investigated in metal-electrolyte-organic semiconductor diodes and electrolyte-gated OFETs. A good correlation is found between the flat-band potential and the threshold voltage. The possibility to tune the threshold voltage over half the potential range applied and to obtain depletion-like (positive threshold voltage) and enhancement (negative threshold voltage) transistors is of great interest when integrating these transistors in logic circuits. The combination of a depletion-like and enhancement transistor leads to a clear improvement of the noise margins in depleted-load unipolar inverters.organic electronics | polyelectrolytes | thin-film transistors | gate electrode material T he possibility to process organic electronic materials from solution allows for printing electronic systems on a wide variety of large area and flexible substrates thus enabling new applications and ultralow cost electronics (1-3). The transistor is a corner stone in modern electronics. The OFETs are promising devices for applications that require medium-speed operation such as driving circuits for displays (4) and sensors (5, 6); however, to enable their integration in portable devices or electronic labels, i.e., distributed systems typically driven by printed batteries (7) or solar cells (8), the OFETs should operate at low voltage and power. A low driving voltage can be achieved by employing a gate dielectric composed of a ultrathin, cross-linked polymer (9), a self-assembled monolayer in combination with a thin metal oxide layer (10), or high-permittivity dielectrics (11); however, high-quality inorganic dielectrics or ultrathin organic dielectrics are normally difficult to combine with common printing technologies. Recently, various electrolytes have successfully been explored as the gate insulator in low-voltage operating OFETs (12-17). In this case, the formation of the gate capacitance includes polarization of electronic and ionic charges. Indeed, if we consider a p-channel OFET, applying a negative voltage to the gate attracts cations from the solution towards the electrolyte/gate interface while anions are repelled towards the electrolyte/semiconductor interface. Such ion redistribution results in the formation of electrical double layers (EDLs) at the two interfaces. These two EDLs can be assimilated to two capacitors in series in which the redistributed ions in the electrolyte are balanced by oppositely charged electronic charge carriers at the gate electrode and in the semiconductor, respectively (Fig. 1A). The ionic and electronic charges within these EDLs are separated by only a few Å resulting in a very high capacitance (typi...

We have previously reported the molecular signature of murine pathogenic TH17 cells that induce experimental autoimmune encephalomyelitis (EAE) in animals. Here we show that human peripheral blood IFN-γ+IL-17+ (TH1/17) and IFN-γ−IL-17+ (TH17) CD4+ T cells display distinct transcriptional profiles in high-throughput transcription analyses. Compared to TH17 cells, TH1/17 cells have gene signatures with marked similarity to mouse pathogenic TH17 cells. Assessing 15 representative signature genes in patients with multiple sclerosis, we find that TH1/17 cells have elevated expression of CXCR3 and reduced expression of IFNG, CCL3, CLL4, GZMB, and IL10 compared to healthy controls. Moreover, higher expression of IL10 in TH17 cells is found in clinically stable vs. active patients. Our results define the molecular signature of human pro-inflammatory TH17 cells, which can be used to both identify pathogenic TH17 cells and to measure the effect of treatment on TH17 cells in human autoimmune diseases.

We report a simple and sensitive label-free immunosensor for detection of microRNAs (miRNA) based on a conducting polymer/reduced graphene oxide-modified electrode to detect miR-29b-1 and miR-141. Square wave voltammetry is used to record the redox signal. Current increases upon hybridization (signal on) from 1 fM to 1 nM of target miRNA. The limit of quantification is ca. 5 fM. The sensor exhibits high selectivity as it distinguishes mismatch. To double-check its selectivity, two specific RNA-DNA antibodies recognizing miRNA-DNA heteroduplexes, antipoly(A)-poly(dT) and anti-S9.6, were used. The antibody complexation with the hybrid leads to a current decrease that confirms the presence of miRNA, down to a concentration of 8 fM. The antibody-hybrid complex can be then dissociated by adding miRNA-DNA hybrids in solution, causing a shift-back on the signal, i.e., an increase in the current density (signal-on). This On-Off-On detection sequence was used as a triple verification to increase the reliability of the results.