Bio-compatible strain sensors based on elastomeric conductive polymer composites play pivotal roles in human monitoring devices. However, fabricating highly sensitive and skin-like (flexible and stretchable) strain sensors with broad working range is still an enormous challenge. Herein, we report on a novel fabrication technology for building elastomeric conductive skin-like composite by mixing polymer solutions. Our e-skin substrates were fabricated according to the weight of polydimethylsiloxane (PDMS) and photosensitive polyimide (PSPI) solutions, which could control substrate color. An e-skin and 3-D flexible strain sensor was developed with the formation of laser induced graphene (LIG) on the skin-like substrates. For a one-step process, Laser direct writing (LDW) was employed to construct superior durable LIG/PDMS/PSPI composites with a closed-pore porous structure. Graphene sheets of LIG coated on the closed-porous structure constitute a deformable conductive path. The LIG integrated with the closed-porous structure intensifies the deformation of the conductive network when tensile strain is applied, which enhances the sensitivity. Our sensor can efficiently monitor not only energetic human motions but also subtle oscillation and physiological signals for intelligent sound sensing. The skin-like strain sensor showed a perfect combination of ultrawide sensing range (120% strain), large sensitivity (gauge factor of ~380), short response time (90 ms) and recovery time (140 ms), as well as superior stability. Our sensor has great potential for innovative applications in wearable health-monitoring devices, robot tactile systems, and human–machine interface systems.

Neurotransmitters (NTs) are crucial regulatory molecules responsible for maintaining the neurophysiological functioning of the brain. Dysregulated levels of certain NTs, such as dopamine, serotonin, norepinephrine, epinephrine, glutamate, and gamma-aminobutyric acid, are often correlated with the pathogenesis of neurodegenerative diseases that involve the progressive and selective loss of structure or function of neuronal systems. Therefore, the identification and validation of relevant biomarkers are essential to diagnose these diseases much earlier. However, the quantitative analysis of NTs is challenging because of their dynamic release and presence of low concentrations. Accordingly, nanocomposite (NC)-based electrochemical sensors have been studied extensively and are gaining tremendous interest due to their high sensitivity, response rate, stability, portability, ease of use in point-of-care diagnostics, amenability to microprocessing, and low cost. In this review, we first briefly discuss the potential biomarkers of neurodegenerative diseases, NC-based electrochemical sensors and their advantages and disadvantages, and the properties of the NCs, which further increase the sensor performance. Finally, we summarized the future perspectives of NC-based electrochemical sensors in the clinical set-up for NTs detection to identify research gaps.

Homogenously dispersed Cu oxide nanoparticles on laser-induced graphene (LIG) were fabricated using a simple two-step laser irradiation. This work emphasized the synergetic photo-electrothermal effect in Cu oxide particles embedded in LIG. Our flexible hybrid composites exhibited high mechanical durability and excellent thermal properties. Moreover, the Cu oxide nanoparticles in the carbon matrix of LIG enhanced the light trapping and multiple electron internal scattering for the electrothermal effect. The best conditions for deicing devices were also studied by controlling the amount of Cu solution. The deicing performance of the sample was demonstrated, and the results indicate that the developed method could be a promising strategy for maintaining lightness, efficiency, excellent thermal performance, and eco-friendly 3D processing capabilities.

In this study, we developed an effective and rapid process for nanoscale ink printing, direct laser interference ink printing (DLIIP), which involves the photothermal reaction of a copper-based metal–organic decomposition ink. A periodically lined copper pattern with a width of 500 nm was printed on a 240 μm-wide line at a fabrication speed of 17 mm/s under an ambient environment and without any pre- or post-processing steps. This pattern had a resistivity of 3.5 μΩ∙cm, and it was found to exhibit a low oxidation state that was twice as high as that of bulk copper. These results demonstrate the feasibility of DLIIP for nanoscale copper printing with fine electrical characteristics.

This study investigated changes in the quality and headspace O2/CO2 concentrations of young radish (Raphanus sativus L.) kimchi (YR-kimchi) packaged using a multilayer (ML) film with or without sachets containing a CO2 absorber and nano-foamed structure (NFS) film, respectively, during storage at −2.2 or 4.0°C. Compared to that in YR-kimchi samples stored at 4.0°C, the total lactic acid bacteria count and titratable acidity of YR-kimchi samples stored at −2.2°C increased rapidly until 21 days of storage, irrespective of the packaging. After 32 days of storage at 4.0°C, the reducing sugar content of young radish kimchi packaged in ML film, ML film with a CO2 absorber sachet, and NFS film decreased by 54.9, 80.7, and 79.9%, respectively, compared to before storage. However, the salinity of YR-kimchi samples packaged with different film types showed negligible differences during storage at −2.2 and 4.0°C. No significant O2 reduction or CO2 accumulation was observed in the headspace of NFS film-packaged young radish kimchi stored at either temperature. Hence, these results indicated that NFS film packaging combined with supercooled (−2.2°C) storage improved the shelf life of YR-kimchi without packaging expansion during storage.