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Label-free electrochemical immunosensors (EIs) are simple and sensitive in cancer diagnosis. Electrode materials which can offer a large specific area and excellent electrical conductivity play a critical role in the fabrication of EIs. In our study, ce-MoS2/AgNR composite was synthesized via Van der Waals force and electrostatic interaction between chemical exfoliated MoS2 nanosheets (ce-MoS2) and Ag nanorods (AgNRs). The conductivity of ce-MoS2/AgNR composite was almost three times higher than single ce-MoS2 because of the synergistic effect between ce-MoS2 and AgNRs. Furthermore, AgNRs could effectively inhibit the stacking of MoS2 nanosheets. The EIs for prostate-specific antigen (PSA) detection were fabricated based on ce-MoS2/AgNR composite. The fabricated EIs retained a wide linear response range (0.1–1000 ng/ml), low sensitivity (0.019 μA/(ng ml−1)), and low detection limit (0.051 ng/ml) for the detection of PSA. Therefore, the EIs based on screen-printed electrode (SPE) and ce-MoS2/AgNR composite could be applied to clinical diagnosis of prostatic cancer and have potential application in the detection of other cancer biomarkers.

Dye-sensitized solar cells (DSSCs) have the advantages of low cost, long life and no pollution. In recent years, DSSCs have rapidly developed into solar cells with commercial application prospects. Photoanodes have a critical impact on the performance of DSSCs. In this paper, photoanodes were prepared by screen printing. The size of titanium oxide, number of screen printing layers, mesh number in photoanode were studied. The surface thickness was observed by laser confocal microscopy, and the most suitable screen printing conditions were selected according to the photoelectric conversion efficiency of dye-sensitized solar cells. The researchon the preparation of DSSCs by screen printing provides an effective way for large-area industrial preparation of DSSCs.

Artificial skin is an important research direction in artificial intelligence and robotics. Response of artificial skin to stimuli in the external environment is multifunctional, including temperature, pressure and so on. In this paper, the integrated film sensor measuring force and temperature can simultaneously sense the external pressure and the temperature stimulation. To build the sensor, the integration of strain and temperature measurement materials is on a PET film. This integrated film sensor then has a good scalability and mechanical performance, and can according to the specific application of environment to carry on various design and application measurement. Thus, such kind of force and temperature integrated thin film sensor can be widely used, especially in artificial skin, intelligent robot, artificial limb, medical examination and so on.

Flexible pressure sensors have attracted tremendous attention from researchers for their widely applications in tactile artificial intelligence, electric skin, disease diagnosis, and healthcare monitoring. Obtaining flexible pressure sensors with high sensitivity in a low cost and convenient way remains a huge challenge. In this paper, the composite dielectric layer based on the mixture of carbon nanotubes (CNTs) with different aspect ratios and polydimethylsiloxane (PDMS) was employed in flexible capacitive pressure sensor to increase its sensitivity. In addition, the screen printing instead of traditional etching based methods was used to prepare the electrodes array of the sensor. The results showed that the aspect ratio and weight fraction of the CNTs play an important role in improving the sensitivity of the printed capacitive pressure sensor. The prepared capacitive sensor with the CNTs/PDMS composite dielectric layer demonstrated a maximum sensitivity of 2.9 kPa&minus, 1 in the pressure range of 0&ndash, 450 Pa, by using the CNTs with an aspect ratio of 1250&ndash, 3750 and the weight fraction of 3.75%. The mechanism study revealed that the increase of the sensitivity of the pressure sensor should be attributed to the relative permittivity increase of the composite dielectric layer under pressure. Meanwhile, the printed 3 &times, 3 and 10 &times, 10 sensor arrays showed excellent spatial resolution and uniformity when they were applied to measure the pressure distribution. For further applications, the flexible pressure sensor was integrated on an adhesive bandage to detect the finger bending, as well as used to create Morse code by knocking the sensor to change their capacitance curves. The printed and flexible pressure sensor in this study might be a good candidate for the development of tactile artificial intelligence, intelligent medical diagnosis systems and wearable electronics.

Metal grid transparent conductive electrodes have been developed by traditional printing techniques, but lower resolution of grid line has limited its performance. In this study, conductive grid patterns with ~10 µm width were created on the polyethylene terephthalate (PET) substrate by microcontact printing (µCP) silver nanoparticles ink. We have found that the composition of silver nanoparticles ink and the O2 plasma treated time of polydimethylsiloxane (PDMS) stamp were critical for the µCP process. Specially, the hole size of stamp has great influence on the patterns shape when using grid-structured stamp. This is because the break of liquid bridge formed between two adjacent lines of stamp depends on the hole size of stamp during the dry process of ink. Larger hole was beneficial for the formation of grid patterns with smooth edge. Conductive grid patterns with typical sheet resistance of 610 Ω/ and 74% transparency were acquired over the entire 1 cm square area using 40 µm hole stamp. This method will lead to a facile strategy to prepare conductive electrode.

In the article, low cost, RFID antenna is fabricated by gravure printing with PET acting as the substrate. The nanosilver ink with 50% silver content is prepared in the lab and the printing speed is set to 5m/min. After sintering at 150°C for 2min, surface resistance of the antenna reaches to 7.31Ω/sq and thickness of the silver layer is 466nm. Then, the antenna is treated at -40°C for 6h. Interestingly, the resistance of the antenna dropped by 9%, which may due to the limited motivation of PVP chain in relatively low temperature. In order to study its stability, the RFID antenna has been put into the night side, sunny side and room temperature for 30 days. The resistance is nearly the same as its original after 1 month, though some decreasing appeared. The result indicates that the antenna fabricated shows excellent stability and the working temperature can range from -40°C to 150°C.

In order to realize measurement for digitally printed line's attributes in accordance with the international standard ISO13660, wavelet de-noising technique is used in pre-processing the CCD digital image with high resolution of hardcopy line prints. First, the line attributes and their measurement indexes are presented. Then, Symltes (SymN) and Coiflets (CoifN) wavelets with hard threshold method are chosen based on theories and experiments. Further, dividing the image signals into two sections, signals of the line itself and the background, and analyzing their de-noising effects with different indexes, the proper wavelet parameters, which are order N in the wavelet functions and decomposition levels, are determined for a high resolution image of a line printed on a ink-jet printer. Experimental results indicate that the most properly parameter N and decomposition levels are 5 and 3 or 4 respectively for SymN, and for CoifN the results are 3 and 3 or 4 respectively. They can satisfy the de-noising requirements of a line CCD image with objectively keeping the line information and the same time smoothing the background information at the most extent.