A label free, reagentless aptasensor for adenosine is developed on an ISFET device. The separation of an aptamer/nucleic acid duplex by adenosine leads to the aptamer/adenosine complex that alters the gate potential of the ISFET. The sensitivity limit of the device is 5 x 10-5 M. Also, the immobilization of the aptamer/nucleic acid duplex on an Au-electrode and the separation of the duplex by adenosine mono-phosphate (AMP) enable the electrochemical detection of adenosine by faradaic impedance spectroscopy. The separation of the aptamer/nucleic acid duplex by adenosine and the formation of the aptamer/adenosine complex results in a decrease in the interfacial electron-transfer resistance in the presence of [Fe(CN)6]3-/4- as redox active substrate.

SUMMARYMicroRNAs (miRNAs) are small RNAs that regulate the expression of target genes post-transcriptionally; they are known to play major roles in development and responses to abiotic stress. miR408 is a highly conserved miRNA in plants that responds to the availability of copper and targets genes encoding copper-containing proteins. It was recently recognized to be an important component of the HY5-SPL7 gene network that mediates a coordinated response to light and copper, illustrating its central role in the response of plants to the environment. Expression of miR408 is significantly affected by a variety of developmental and environmental conditions; however, its biological function is unknown. Involvement of miR408 in the abiotic stress response was investigated in Arabidopsis. Expression of miR408, as well as its target genes, was investigated in response to salinity, cold, oxidative stress, drought and osmotic stress. Analyses of transgenic plants with modulated miR408 expression revealed that higher miR408 expression leads to improved tolerance to salinity, cold and oxidative stress, but enhanced sensitivity to drought and osmotic stress. Cellular antioxidant capacity was enhanced in plants with elevated miR408 expression, as manifested by reduced levels of reactive oxygen species and induced expression of genes associated with antioxidative functions, including Cu/Zn superoxide dismutases (CSD1 and CSD2) and glutathione-S-transferase (GST-U25), as well as auxiliary genes: the copper chaperone CCS1 and the redox stress-associated gene SAP12.Overall, the results demonstrate significant involvement of miR408 in abiotic stress responses, emphasizing the central function of miR408 in plant survival.

In recent decades, flexible and wearable devices have been extensively investigated due to their promising applications in portable mobile electronics and human motion monitoring. MXene, a novel growing family of 2D nanomaterials, demonstrates superiorities such as outstanding electrical conductivity, abundant terminal groups, unique layered-structure, large surface area, and hydrophilicity, making it to be a potential candidate material for flexible and wearable devices. Numerous pioneering works are devoted to develop flexible MXene-based composites with various functions and designed structures. Therefore, the latest progress of the flexible MXene-based composites for wearable devices is summarized in this review, focusing on the preparation strategies, working mechanisms, performances, and applications in sensors, supercapacitors, and electromagnetic interference shielding materials. Moreover, the current challenges and future outlooks are also discussed.