The study of brain signals is now going beyond the traditional study of electrogenic neuronal cells. Currently, it has been demonstrated that even non-electrogenic cells present in the brain such as ...astrocytes can concur to physiological brain communication. Indeed, in the so-called tripartite synapse model, the small extracellular ionic currents, exchanged between astrocytes and neurons, are of interest to deeply understand local processes of transfer and storage of information. Current electrodes are limited by high-impedance and low selectivity and cannot efficiently detect signals in the range of few uV. A method to overcome these issues is the use of nanostructured glio-friendly electrodes for the development of low-impedance recording devices. In this work we present a new nanostructured bio-junction where Zinc Oxide nanorods can be implemented to improve impedance properties, while the addition of reduced Graphene Oxide is crucial to increase astrocyte adhesion and differentiation.
In this work, we present a comparison among four different piezoelectric materials (PVDF-TrFE, Piezopaint, AlN and ZnO), all deposited at low temperature (from RT up to 160 °C) on flexible substrate ...such as thin Polyimide, in order to investigate their possible implementation as flexible tactile sensors. Flexible capacitive sensors were tested by using a mini-shaker, investigating the sensors behavior in force and frequency with the intent of mimicking the human sense of touch. We optimized the piezoelectric properties of the materials by using specific texturing buffer layers or maximizing the poling procedure to increase the dipole alignment. Finally, by using a multi-foil approach, the different sensors have been integrated with polysilicon thin film transistor fabricated on flexible substrates and the specific device sensitivity was evaluated.
We present a novel method for the extraction of the relevant electrical and physical parameters of Schottky diodes realized on polycrystalline thin films. The proposed approach relies on a limited ...set of current-voltage characteristics measured at different temperatures and does not require the previous knowledge of any semiconductor parameter. The procedure provides satisfactory results in terms of relative errors even in the case of nonideal characteristics, including a very large series resistance and strong temperature and bias dependence of both barrier and ideality factor. We tested the approach on both simulated devices and real Cr-poly-Si Schottky diodes.
To effectively control gaseous pollutants in air it is mandatory to fabricate reliable and non-expensive monitoring systems that can be easily deployed in urban areas. Sensing devices based on metal ...oxide nanostructures offer many advantages respect bulk material in detecting multiple hazardous gases such as, high stability, easy surface functionalization and potentially low operating temperature. Among diverse nanostructures, ZnO nanorods can be obtained with low cost and simple process at a low manufacturing temperature opening the possibility to integrate the material with flexible substrates. Additionally, laser annealing procedure can be exploited to improve or tune the morphology and the electrical properties of these materials. In this work, we present a comparison between the performance of as deposited and laser-annealed devices in the detection of NO and NO 2 . Different sensors characteristics at increasing gas concentrations and dynamic behaviors are shown and discussed evaluating the mechanisms involved in the diverse pollutant detection. As result, the laser-annealed sensor exhibits a sensitivity one-order higher respect to as-grown sample in detecting NO (3.9x10 -3 vs 2.7x10 -4 1/ppm) while for NO 2 sensitivity is more than four times higher (3.8x10 -3 vs 8.4x10 -4 1/ppm).
Silicon nanowires (SiNWs) are attractive functional nanomaterials for biomedical applications. The ability to easily tune their size and density, potential biocompatibility, and knowledge of the ...chemical activation of SiNWs surface make them natural tools to interact with biological materials. We evaluated the possibility of exploiting SiNWs as carriers to introduce organic compounds into cells. The cellular toxicity and the internalization capacity of free-standing and label-free SiNWs were tested on Buffalo Green Monkey cells (BGM). Confocal fluorescent observation of SiNWs conjugated with fluorescein-polyethylene imine (PEI) confirmed the internalization of the NWs into the Buffalo Green Monkey Cells (BGM).
In this work we present a WSN architecture for precision agriculture. The network is built on a star configuration with two protocols of connectivity: NB-IoT for the gateway and LoRa for sensor ...nodes. Sensor node owns solar harvesting and radio communication capabilities, low power MCU for simple edge computing, I2C and analog interface for sensors. The hardware has been designed to enable deep-sleep current <1μA. Communication protocol between nodes and the gateway has been optimized to allow synchronization of the transmission/reception window while maximizing the sleep time, contributing to further reduce the power budget of the node. We demonstrate that all these features enable battery-less operativity in specific scenarios.
Genomic deoxyribonucleic acid (DNA) stores and carries the information required to maintain and replicate cellular life. While much efforts have been devoted in decoding the sequence of DNA basis to ...detect the genetic mutations related to cancer disease, it is becoming clear that physical properties, like structural conformation, stiffness and shape, can play an important role to recognize DNA modifications. Here, silver-coated silicon nanowires (Ag/SiNWs) are exploited as Raman spectroscopic platform to easily discriminate healthy and cancer genomic DNA, extracted from human normal skin and malignant melanoma cells, respectively. In particular, aqueous DNA droplets are directly deposited onto a forest of Ag/SiNWs and Raman maps are acquired after sample dehydration. By applying principal component analysis (PCA) to the Raman spectra collected within the droplets, healthy and cancer cell DNA can be distinguished without false negative identifications and with few false positive results (< 2%). The discrimination occurs regardless the analysis of specific DNA sequencing, but through Raman bands strictly related to the interfacing of the DNA and the NWs. The observed phenomenon can be ascribed to conformational differences and/or diverse charge properties between healthy and cancer cell DNA determining a different arrangement of the molecules adsorbed onto the NWs upon water evaporation. The unique interaction with DNA and facile fabrication technology make Ag/SiNWs an effective platform for a robust, rapid and label-free cancer diagnosis, as well as a potential tool to investigate physical properties of DNA.
Display omitted
•Label free Raman maps to discriminate normal and cancer genomic DNA without DNA sequence analysis•Diagnostic information based on the physical interaction of the DNA with Ag/SiNWs•Facile detection and fabrication method make Ag/SiNWs an effective tool for cancer diagnosis and study
PDF
