Bio-conductivity characteristics of chronic kidney disease stages examined by portable frequency-difference electrical impedance tomography.

Chronic kidney disease (CKD) is an escalating global health concern, and non-invasive means for early CKD detection is eagerly awaited. Here, we explore the potential of using home-based frequency-difference electrical impedance tomography (fdEIT) to evaluate CKD based on bio-conductivity characteristics. We first verified the feasibility of using portable EIT capturing bio-conductivity in fresh pig kidneys ex vivo. We further performed bio-conductivity measurement in vivo paired with standard eGFR measurements on CKD patients by EIT and traditional blood test, respectively. Our results showed a significant correlation between renal bio-conductivity changes captured by fdEIT and standard eGFR scores. These results hold promise to be developed into a non-invasive and portable device for early CKD detection and longitudinal CKD treatment monitoring in clinical, community and home-based settings. Clinical Relevance - A novel non-invasive bio-conductivity approach was developed for CKD classification. The renal assessment with portable EIT device demonstrated the potential to ameliorate the detection and classification of CKD into a portable, accessible, self-administrable home-based process.

Thermoresponsive cellulosic hydrogels with cell-releasing behavior.

Here we report the preparation and characterization of thermoresponsive cellulosic hydrogels with cell-releasing behavior. Hydroxypropyl cellulose (HPC) was modified with methacrylic anhydride (MA). The resultant macromonomer, HPC-MA, retains the characteristic thermoresponsive phase behavior of HPC, with an onset temperature of 36 °C and a lower critical solution temperature (LCST) of 37-38 °C, as determined by turbidity measurement. Homogenous HPC-MA hydrogels were prepared by UV-cross-linking the aqueous solutions of the macromonomer at room temperature, and characterized by water contact angle and swelling ratio measurements, and dynamic mechanical analysis. These hydrogels exhibit temperature-dependent surface hydrophilicity and hydrophobicity, equilibrium water content as well as mechanical properties. Cell-releasing characteristics were demonstrated using African green monkey kidney cell line (COS-7 cells) and murine-derived embryonic stem cell line (Oct4b2). By reducing temperature to 4 °C, the cultivated cells spontaneously detached from the hydrogels without the need of trypsin treatment. These unique properties make our HPC-MA hydrogels potential substrates for cell sheet engineering.

Transformative Reality: improving bionic vision with robotic sensing.

Implanted visual prostheses provide bionic vision with very low spatial and intensity resolution when compared against healthy human vision. Vision processing converts camera video to low resolution imagery for bionic vision with the aim of preserving salient features such as edges. Transformative Reality extends and improves upon traditional vision processing in three ways. Firstly, a combination of visual and non-visual sensors are used to provide multi-modal data of a person's surroundings. This enables the sensing of features that are difficult to sense with only a camera. Secondly, robotic sensing algorithms construct models of the world in real time. This enables the detection of complex features such as navigable empty ground or people. Thirdly, models are visually rendered so that visually complex entities such as people can be effectively represented in low resolution. Preliminary simulated prosthetic vision trials, where a head mounted display is used to constrain a subject's vision to 25×25 binary phosphenes, suggest that Transformative Reality provides functional bionic vision for tasks such as indoor navigation, object manipulation and people detection in scenes where traditional processing is unusable.

Uniform mixing in paper-based microfluidic systems using surface acoustic waves.

Paper-based microfluidics has recently received considerable interest due to their ease and low cost, making them extremely attractive as point-of-care diagnostic devices. The incorporation of basic fluid actuation and manipulation schemes on paper substrates, however, afford the possibility to extend the functionality of this simple technology to a much wider range of typical lab-on-a-chip operations, given its considerable advantages in terms of cost, size and integrability over conventional microfluidic substrates. We present a convective actuation mechanism in a simple paper-based microfluidic device using surface acoustic waves to drive mixing. Employing a Y-channel structure patterned onto paper, the mixing induced by the 30 MHz acoustic waves is shown to be consistent and rapid, overcoming several limitations associated with its capillary-driven passive mixing counterpart wherein irreproducibilities and nonuniformities are often encountered in the mixing along the channel--capillary-driven passive mixing offers only poor control, is strongly dependent on the paper's texture and fibre alignment, and permits backflow, all due to the scale of the fibres being significant in comparison to the length scales of the features in a microfluidic system. Using a novel hue-based colourimetric technique, the mixing speed and efficiency is compared between the two methods, and used to assess the effects of changing the input power, channel tortuousity and fibre/flow alignment for the acoustically-driven mixing. The hue-based technique offers several advantages over grayscale pixel intensity analysis techniques in facilitating quantification without limitations on the colour contrast of the samples, and can be used, for example, for quantification in on-chip immunochromatographic assays.