SciTech #ScienceSunday Digest – 15/2015.
Permalink here: http://www.scitechdigest.net/2015/04/artificial-kidney-membrane-nanoscale-3d.html
Artificial kidney membrane, tissue engineered gonads, nanotube computing, 3D imaging chip, Nanoscale 3D imaging, Simpler CRISPR, Maintaining youthful stem cells, Tactile manipulators, Acoustic cell isolation, Acoustic metamaterials.
1. Living Artificial Kidney Membrane.
In a similar vein to recent efforts in microfluidics to develop “organs on a chip” artificial membranes can now be produced that are coated by a living monolayer of kidney cells http://phys.org/news/2015-04-kidney-membrane.html. The primary application the group is pursuing relates to kidney transplants and dialysis treatments by ultimately scaling the device up to achieve clinical relevance. One can imaging rolling layers of membranes with relevant cells into tubes to form an artificial kidney or other organ system – artificial organs and tissue engineering needn’t be limited to conventional biological architectures. I also like the idea of controlled cell membranes in general; they might be programmed to mass produce any biological product of interest.
2. Tissue Engineering: Artificial Testicles.
In related tissue engineering news we had an interesting article this week about the ongoing development of artificial testicles capable of producing functional sperm http://www.vice.com/read/the-science-of-artificial-testicles. The current (complex) device is designed to mimic the complex inner structure of testicles and the primary applications in mind are for aiding men struggling with infertility for a range of reasons to have children via IVF. The key here is engineering the right environment to naturally stimulate stem cells – convincing them that they are part of a testicle – to divide and differentiate into sperm cells, to take tissue engineering to the point of creating a sperm-making machine.
3. Carbon Nanotube Computing.
Circuits made of carbon nanotubes take another step closer to fruition with a simple, scalable method to remove metallic carbon nanotubes from arrays and leaving the desired semiconducting nanotubes behind to do work http://phys.org/news/2015-04-purify-arrays-single-walled-carbon-nanotubes.html. Making defined arrays of nanotubes into circuits can already be done but until now making these circuits functional by removing metallic carbon nanotubes has not been possible. In related news carbon nanotube and polymer composites, inherently disordered bulk materials, can nevertheless be trained to produce a desired electronic output (mimicking a particular electronic circuit) as part of a process of materials evolution http://phys.org/news/2015-04-single-walled-carbon-nanotube-composites-great.html; understanding how these structures form might be very useful http://munews.missouri.edu/news-releases/2015/0409-engineers-now-understand-how-complex-carbon-nanostructures-form/.
4. Chip-Based 3D Imaging for Devices.
A new millimeter-scale silicon chip incorporates a nanophotonic coherent imager – in which each pixel is an independent interferometer able to measure both intensity and distance information – that works as part of a LIDAR system to generate 3D images of objects in realtime http://www.caltech.edu/news/new-camera-chip-provides-superfine-3-d-resolution-46425. These are just begging to be incorporated into smartphones, Kinect / Leap Motion devices, and autonomous vehicles to name a few; remember one of the major expenses on an autonomous vehicle is the LIDAR system – chips like this will slash these costs. I wonder if the chip might be used in a different set-up to emit rather than capture 3D images?
5. Nanoscale Optical 3D Imaging.
In related 3D imaging news, but this time at the nanoscale, a new imaging technology combining cathodoluminescence and tomography allows the use of visible light to generate nanometer resolution three-dimensional images of nanoscale objects http://news.stanford.edu/news/2015/april/nano-3d-imaging-040715.html. The technique takes many 2D images at many angles and uses algorithms to stitch these together to generate and identify the 3D structure of the object. There is a nice embedded video overview of the process. This is a nice new imaging platform that I’d expect to see used in many fundamental research investigations over time; the team quote applications in producing optimised and more efficient LEDs and photovoltaic materials.
6. Simpler Mini CRISPR.
As if CRISPR couldn’t get any easier. The CRISPR gene editing toolkit has been expanded with a new Cas9 enzyme that is encoded by a gene that is only 75% of the size of the conventional Cas9 gene http://www.nature.com/news/mini-enzyme-moves-gene-editing-closer-to-the-clinic-1.17234. This makes the overall genetic package require to be inserted into cells that much smaller and that much easier / more effective to insert. This is particularly important for gene therapy approaches in which you typically need to package genes into a small virus particle. In proof-of-concept experiments the team used the new technique to successfully transfect the livers of mice and get a test gene into 40% of liver cells in one go – a pretty good result for somatic cell genetic modification.
7. Maintaining Youthful Stem Cell Activity with Age.
New experiments in mice show that removing just two factors known as TIMP1 and TIMP3 (Tissue Inhibitors of MetalloProteinases) was enough to maintain tissue (breast tissue in this demonstration) in a youthful state in aged mice https://www.fightaging.org/archives/2015/04/loss-of-timp1-and-timp3-maintains-youthful-stem-cell-activity-in-aging-mice.php. With age tissue loses its ability to develop and repair due to a decline in the stem cell population. Removal of TIMP1 & 3 led to an expansion in the pool of stem cells, the maintenance of consistently high levels, and their remaining functional throughout the life of the mice, and all without an increased predisposition to cancer (which was originally predicted). I wonder when we might see the results of, e.g., RNAi knock-down of TIMP1 & 3 in humans?
8. Sensitive Robot Manipulators.
A couple of interesting advances in robotic hands enabling more sensitive manipulations this week. First, engineering new robotic hands that are much more touch sensitive by using touch sensors interacting with myriad different materials to build a “language” of touch that both a computer and human can understand and interpret http://www.nsf.gov/news/special_reports/science_nation/robotictouch.jsp?WT.mc_id=USNSF_51, with the hope this results in prosthetics that provide a genuine human touch experience to amputees. Second, the use of shape-memory alloys (wires) as muscle fibers in lightweight robotic and prosthetic hands and limbs http://www.kurzweilai.net/an-artificial-hand-that-can-respond-sensitively-thanks-to-muscles-made-of-shape-memory-wires and leveraging useful properties such as the highest energy density of all known drive mechanisms.
9. Isolating Circulating Tumour Cells with Sound.
Building on work first demonstrated last year a group has developed an even better (20 times faster) microfluidic cell sorting chip powered by two acoustic transducers that produce a standing wave along the microchannel http://newsoffice.mit.edu/2015/sound-waves-detect-rare-cancer-cells-0406. It turns out that cancer cells and normal cells respond differently to the sound gradient due differences in compressibility and other factors. In tests 83% of cancer cells were isolated samples with as few as 1 cancer cell per 100,000 and blood samples from real cancer patients were successfully analysed. The order-of-magnitude improvement from last year makes the device clinically relevant.
10. Acoustic Metamaterials.
On the topic of acoustic technology there were two interesting acoustic metamaterial advances this week http://nextbigfuture.com/2015/04/new-industrial-bubble-wrap-material-and.html. First, a bubble metascreen comprised of a 4mm thick rubber film with embedded bubbles can dampen sound and especially reflected sonar signals by 10,000 times – 100 times better than thought possible. Second, another acoustic metamaterial dubbed a phononic crystal can, when coated onto an object, cause sound waves hitting that object to flow around its surface without being reflected.
Archive:_ http://www.scitechdigest.net/2015/04/artificial-kidney-membrane-nanoscale-3d.html
