Publications

The contractile nature of skeletal muscle tissue makes it especially attractive for powering biohybrid actuators. Significant efforts have been dedicated to the improvement and control of contraction force, going one step forward toward the automation of these biohybrid platforms. Herein, 3D-bioengineered skeletal muscle tissues are integrated with organic transistor-based sensors to define a soft bioactuator with real-time force monitoring capabilities. The muscle tissue is electrically stimulated while the organic sensor ensures transduction of the exerted force into an electrical signal that allows direct monitoring of the bioactuator performance. Sensor calibration is carried out to define its sensitivity at different biasing conditions: as opposed to standard, two-terminal piezoresistive devices, transistor-based strain sensors show tunable sensitivity by acting on the voltage applied to a third terminal-the gate. A complete evaluation of sensing performances is provided, demonstrating that real-time monitoring is effective under different conditions, including stimulation signal frequency and chemical modulation of the bioactuator contraction, demonstrating its potential use as a drug testing platform. In the reported results, the way is paved for a complete exploitation of organic devices in soft robotic applications and to the development of novel biohybrid machines in bioengineering and biomedicine. The integration of sensing elements in bioengineered actuators is key to obtain real-time information about their performance and further control/automation. By coupling flexible organic field-effect transistor to a skeletal muscle actuator we demonstrate the feasibility to record in real-time its contractile behavior when stimulated by electrical pulses, showing both high sensitivity absence of cross talk between stimulation and readout.image (c) 2024 WILEY-VCH GmbH

JTD Keywords: Bioengineerings, Flexible electronics, Muscle-based actuators, Organic field-effect transistors, Soft robotic

Charge transport in electrolyte-gated organic field-effect transistors (EGOFETs) is governed by the microstructural property of the semiconducting thin film that is in direct contact with the electrolyte. Therefore, a comprehensive nanoscale operando characterization of the active channel is crucial to pinpoint various charge transport bottlenecks for rational and targeted optimization of the devices. Here, the local electrical properties of EGOFETs are systematically probed by in-liquid scanning dielectric microscopy (in-liquid SDM) and a direct picture of their functional mechanism at the nanoscale is provided across all operational regimes, starting from subthreshold, linear to saturation, until the onset of pinch-off. To this end, a robust interpretation framework of in-liquid SDM is introduced that enables quantitative local electric potential mapping directly from raw experimental data without requiring calibration or numerical simulations. Based on this development, a straightforward nanoscale assessment of various charge transport bottlenecks is performed, like contact access resistances, inter- and intradomain charge transport, microstructural inhomogeneities, and conduction anisotropy, which have been inaccessible earlier. Present results contribute to the fundamental understanding of charge transport in electrolyte-gated transistors and promote the development of direct structure-property-function relationships to guide future design rules. This study delves into the charge transport properties of electrolyte-gated organic field-effect transistors by employing in-liquid scanning dielectric microscopy. By introducing a novel interpretation framework, the research achieves quantitative mapping of the local electric potential, facilitating a detailed assessment of charge transport bottlenecks across all operational regimes. The findings can fosterthe formulation ofstructure-property-function relationships for device optimization.image

JTD Keywords: Conduction anisotropy, Conductivity maps, Electrolyte-gated organic field-effect transistors, Nanoscale, Operando, Operation regimes, Potential maps, Scanning dielectric microscopy

Analytical devices able to perform accurate and fast automatic DNA detection or sequencing procedures have many potential benefits in the biomedical and environmental fields. The conversion of biological or biochemical responses into quantifiable optical, mechanical or electronic signals is achieved by means of biosensors. Most of these transducing elements can be miniaturized and incorporated into lab-on-a-chip devices, also known as Micro Total Analysis Systems. The use of multiple DNA biosensors integrated in these miniaturized laboratories, which perform several analytical operations at the microscale, has many cost and efficiency advantages. Tiny amounts of reagents and samples are needed and highly sensitive, fast and parallel assays can be done at low cost. A particular type of DNA biosensors are the ones used based on electrochemical principles. These sensors offer several advantages over the popular fluorescence-based detection schemes. The resulting signal is electrical and can be processed by conventional electronics in a very cheap and fast manner. Furthermore, the integration and miniaturization of electrochemical transducers in a microsystem makes easier its fabrication in front of the most common currently used detection method. In this review, different electrochemical DNA biosensors integrated in analytical microfluidic devices are discussed and some early stage commercial products based on this strategy are presented.

JTD Keywords: DNA, Electrochemical DNA biosensors, Electrochemistry, Lab-on-a-chip, Micro Total Analysis systems, Field-effect transistors, Sequence-specific detection, Chemical-analysis systems, Solid-state nanopores, Carbon nanotubes, Microfluidic device, Electrical detection, Hybridization, Molecules, Sensor