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β-Amino residues are regarded as extremely rare features among ribosomal products. They can be installed by a remarkable non-canonical enzymatic splicing process occurring in some Nif11-type ribosomally synthesized and posttranslationally modified peptide (RiPP) pathways from select cyanobacteria. The functions of the final pathway products remained unknown. Here, a global bioinformatic analysis suggested an unexpectedly broad distribution of ribosomal β-amino acid products in diverse bacterial lineages as well as archaea. Characterization of 27 bacterial splicease-substrate pairs confirmed the modification in all cases. The “spliceotide” products include many previously unrecognized RiPP types as well as proteins, contain 35 to >600 residues, and feature single to multiple α-keto-β-amino acid moieties, with 15 different naturally occurring β units characterized and 20 predicted. Of three tested spliceotides, all exhibited exceptionally potent protease inhibitory activity, providing a potential rationale for the widespread splicease chemistry in prokaryotes and highlighting substantial potential for drug discovery and gene-based biomolecule diversification. ISSN:2451-9294 ISSN:2451-9308

DNA amplification reactions are often used for nucleic acid analysis on lab-on-chip devices. In view of point of care testing e.g. for pathogen detection in emergency stations, such an analysis must be fast and simple to be performed. As an alternative to fluorescence based measurements the method presented here is based on detecting the change in the rheological properties of the assay. For the first time, on chip DNA amplification with real time viscometric detection is shown, with first results already being available after less than 20 min. The change of the sample's viscosity during the polymerization employing the rolling circle amplification (RCA) is detected using a micromachined vibrating cantilever. The RCA was chosen, as it is isothermal and produces very long strands resulting in a high change of the fluid's rheological properties. As the reaction proceeds, an increase of the cantilever's damping and required excitation power to keep its amplitude constant is observed in real-time. Evaluating the slope of these two parameters e.g. 27 min after starting the reaction, samples where polymerization takes place and samples without reaction can perfectly be distinguished. The described approach works without explicit functionalization of the sensor surface or labeling of reaction components.

The realization of a vertically moving micromirror using electrostatic actuation in a comb drive configuration is presented. The micromirror is designed for the use in tunable mid-infrared Resonant Cavity Enhanced Detectors (RCEDs). It can be displaced more than 2.5 μm with less than 30 V actuation voltage. In addition to the pure out-of-plane movement, the mirror can be tilted by applying different voltages at the different comb drive actuators. A voltage difference of 30 V on opposite comb drive actuators induces a mirror tilt of 0.23°. Measured spectra of a tunable RCED employing the presented micromirror are included.

Recent market studies mention the necessity to include sensors in the design of organic electronic devices in order to broaden the range of applications. It is therefore essential to identify potential organic mechanical sensor materials and to develop processes and methods to structure them and characterize their piezoresistive properties. Furthermore, it is also essential for organic electronic devices to know the change of resistance upon bending of flexible substrates. A material widely used in organic electronics is the complex of the intrinsically conductive polymer poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate acid (PEDOT/PSS). In this paper first the fabrication of a polyimide (PI) membrane with integrated PEDOT/PSS strain gauges is presented. Upon a pressure difference the membrane is deflected and the resulting changes in resistance of the sensor elements are recorded. By applying a membrane mechanics model the resistance changes can be linked to the strain in the membrane and then the plane strain gauge factor k"P"S for PEDOT/PSS of 0.48+/-0.07 at 36.6+/-3% rH can be determined.

In recent years first commercial devices based on organic electronic materials entered the market. Recent market studies mention the necessity to include sensors in the design of organic electronic devices in order to broaden the range of applications. It is therefore essential to identify potential organic sensor materials and to develop processes and methods to structure and characterize them. Widely used in organic electronics is the complex of the intrinsically conductive polymer poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate acid (PEDOT/PSS). In this paper we first present a lift-off process for patterning thin PEDOT/PSS films. Crucial deposition parameters are systematically investigated and subsequently a reliable micropatterning process defined. Then a design for fully polymeric pressure sensors made from polyimide (PI) membranes and PEDOT/PSS strain sensors is proposed. Preliminary test results as proof-of-concept are finally shown.

When measuring the properties of fluids from biological sources, sample volumes in the micro-liter range are often desired as higher volumes may not be available or are very expensive. Miniaturized viscosity and density sensors based on a vibrating cantilever fulfill this requirement. In this paper, the possibility of measuring viscosity and density of DNA solutions at the same time using such a sensor is shown. The sensor requires a sample volume of 10 μl. By doing a titration of a solution containing 110 bp long strands of DNA in the diluted, Newtonian regime, the intrinsic viscosity can be determined to be 0.047 ml mg(-1) using the cantilever sensor. The cantilever is also tested with solutions of 10 kbp long strands with concentrations in the semi-dilute, non-Newtonian regime. The comparably small change in resonance frequency and damping observed using these solutions at 12.5 kHz is attributed to shear thinning, which is expected when extrapolating results from other groups.

This paper proposes a novel method for an inductive readout of vibrating MEMS cantilever structures submerged in a liquid. The excitation of the system is separated in time from the detection of the cantilever oscillation. With this strategy the resonance frequency and damping are quantified overcoming the problem of measuring a small amplitude signal while applying a large amplitude signal for the excitation at the same time. An application to loop and plate shaped viscosity and density sensors is shown. Measurements with mixtures of glycerol, ethylene glycol and water are presented. The sensors exhibit very high sensitivity while requiring simple instrumentation.

A chip-based viscosity and density sensor which requires a sample volume of less than 10 colonl is presented. A resistive heater and a temperature sensor are provided for accurate and fast temperature dependent measurements. An inductive readout of the resonance frequency and the damping further facilitates the measurement procedure. Thereby high resolution measurements of fluid properties are easily made in view of their analysis in the context of thermorheologically simple materials., Procedia Engineering, 25, Eurosensors XXV

This paper describes a hybrid silicon/plastic chip which is used to analyze DNA samples without the need of fluorescence or surface functionalization. The viscosity and density of the solutions to be tested are measured using a vibrating silicon beam immersed in the fluid. The sensitivity of the chip with respect to DNA concentration and length is analyzed, yielding a limit of detection of 0.5 μg/μl. We show that the sensitivity of the chip is statistically significant for PCR end-point detection. State-of-the-art on-chip detection methods of DNA solutions need optical devices or specially designed reactions. With the viscometric method proposed in this paper, these drawbacks are avoided., Procedia Engineering, 47, 26th European Conference on Solid-State Transducers, EUROSENSOR 2012

Results on a tunable resonant cavity enhanced detector (RCED) in the mid-infrared employing a vertically moving, comb-drive actuated micromirror are presented. A wide tuning range of 0.7 mum and a low order configuration have been achieved with a micromirror displacement range of 2.5 mum and a reduction of the optical cavity length respectively.