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Soft artificial skin capable of sensing touch, pressure and bending similar to soft human skin is important in many modern-day applications including socially interactive robotics, modern healthcare, augmented reality, etc. However, most of the research effort on soft artificial skin are confined to the lab-scale demonstration. We have demonstrated how a fundamental understanding of the contact mechanics of soft material and a specially constructed soft optical waveguide let us develop a highly efficient, resilient, and large-area soft artificial skin for futuristic applications. The soft artificial skin capable of detect touch, load and bending shows extreme sensitivity (up to \({150 \text{k}\text{P}\text{a}}^{-1}\)) to touch, and load, which is 750 times higher than earlier work. The soft-a-skin shows excellent long-term stability i.e. it shows consistent performance up to almost a year. In addition, we describe a 3D printing process capable of producing large areas, large numbers yet cost-effective soft artificial skin. We have shown the functioning of the soft-a-skin in various means.

We present an on chip optofluidic surface deformable liquid Dove prism (LDP) based low-fluid flow pressure monitoring device. The unique design of the device in combination with liquid and soft solid enabled by the total internal reflection of light makes the sensor highly sensitive and compatible with the integration of a microfluidic and/or Lab-on-a-chip device. A layer-by-layer soft lithographic (LSL) and 3D printing technique are exploited to make the device. We have used Polydimethylsiloxane (PDMS) as the layer material and two variety of liquids (a) immersion oil (IO) and (b) di-iodomethane (DI) as refracting medium to construct the LDP sensor. Optical ray tracing simulation is performed to optimize the sensor. The pressure sensor shows sensitivity as high as ±28.5 mV per 50 Pa pressure with an error ± 2.5 mV and repeatability of ~99.56% at full scale. We have shown the applicability of the sensor by capturing and analyzing respiratory pressure signals of some human subjects at numerous conditions.

Microfluidic devices have been developed for imaging behavior and various cellular processes in Caenorhabditis elegans, but not subcellular processes requiring high spatial resolution. In neurons, essential processes such as axonal, dendritic, intraflagellar and other long-distance transport can be studied by acquiring fast time-lapse images of green fluorescent protein (GFP)-tagged moving cargo. We have achieved two important goals in such in vivo studies namely, imaging several transport processes in unanesthetized intact animals and imaging very early developmental stages. We describe a microfluidic device for immobilizing C. elegans and Drosophila larvae that allows imaging without anesthetics or dissection. We observed that for certain neuronal cargoes in C. elegans, anesthetics have significant and sometimes unexpected effects on the flux. Further, imaging the transport of certain cargo in early developmental stages was possible only in the microfluidic device. Using our device we observed an increase in anterograde synaptic vesicle transport during development corresponding with synaptic growth. We also imaged Q neuroblast divisions and mitochondrial transport during early developmental stages of C. elegans and Drosophila, respectively. Our simple microfluidic device offers a useful means to image high-resolution subcellular processes in C. elegans and Drosophila and can be readily adapted to other transparent or translucent organisms.

The authors report on-chip dynamic optimization of polymerase chain reaction PCR based on a feedback technique utilizing synchronous detection of intracycle fluorescence every 500 ms. From a direct measurement of polymerase activity, the authors determine the optimum extension temperature. The authors dynamically optimize PCR in an inductively heated microchip by sensing the saturation of extension in each cycle and applying the feedback. They demonstrate that, even with fast ramp rates, dynamic optimization leads to faster reactions compared to fixed-duration extension protocols for long DNA (>500 bp). This optimization scheme uses a fairly universal dye Sybr Green I and can be applied to most PCRs.