Our bodies rely on many types of tube-shaped organs to transport blood, air, water, food, urine, and feces. These tubular organs are stimuli-responsive: they can constrict or dilate, secrete chemicals, or act as a selective barrier in response to biological signals. Developing synthetic versions of natural tissue structures that mimic biological responses is at the cutting edge of tissue engineering, synthetic organ development, and even soft robotics design. But what materials can be used to grow responsive tubes in the lab?
The texture of food products can be tailored so you feel them as soft or hard in your mouth. The measure of food texture is achieved by using tools like a compression machine with two metallic plates to mimic the compression between your tongue and palate. However, the results from these measurements can disagree with the texture we actually perceive because the bottom metallic plate of the machine does not reproduce the deformability of our tongue. This missclassification is especially dangerous for people with swallowing problems who can only eat soft foods. A team of Japanese researchers developed a test machine with a silicone rubber artificial tongue on the bottom metallic plate to better assess food texture.
Understanding the origin of life is one of the most enduring and fundamental scientific challenges there is. Of all branches of science, physics is probably not the first place one would think to go to for enlightenment. Life seems too complicated and multi-layered to be captured by the simplistic frameworks of physics. Today’s paper tackles a small part of understanding the origin of life – the physics of self-replication.
Plants need to know the direction of gravitational pull in order to grow their roots downward and their stems upward. This information is crucial whether the plant grows in your garden, on a cliffside, or even on the International Space Station . While it’s been said that it took a falling apple for Newton to figure out how gravity works, our photosynthetic friends use a more intricate microscale sensor to detect gravity. This sensor consists of starchy granules called statoliths which can be found on the bottom of specialized cells called statocytes.
How do squid build a self-assembling “perfect” lens? Research reveals that diffusion and cell biology are the key.
Pulling too hard on a synthetic soft material like a rubber band usually leads to its failure. However, some biological soft materials, like our muscles, experience the opposite behavior. Our muscles, for instance, grow by repairing damage caused by a mechanical effort, such as lifting weigths. A team of researchers from Hokkaido University successfully mimicked this biological process and applied it to develop hydrogels that get stronger under tensile stress.
Quintessential soft matter problems, such as the behavior of droplets in ink-jet printing, involve complex interactions between forces and materials. In today’s article, Prof. Wilson Poon points out that coronaviruses are also quintessential soft matter objects, and highlights a range of areas where soft matter science may help better understand, and combat viral pandemics.
If you speak to a soft matter physicist these days, within a few minutes the term “active matter” is bound to come up. A material is considered “active” when it burns energy to produce work, just like all sorts of molecular motors, proteins, and enzymes do inside your body. In this study, the scientists are focusing specifically on active polymers. These are long molecules which can burn energy to do physical work. Much of biological active matter is in the form of polymers (DNA or actin-myosin systems for example), and understanding them better would give direct insight into biophysics of all kinds. But polymers are microscopic objects with complex interactions, making them difficult to manipulate directly. To make matters worse, physicists have yet to fundamentally understand the behaviors of active materials, since they do not fit into our existing theories of so-called “passive” systems. In this study, Deblais and colleagues decided to entirely circumvent this problem by working with a much larger and easier-to-study system that behaves similarly to a polymer solution: a mixture of squirming worms in water.
An alien spaceship commander was preparing to drop a cone-shaped spy shuttle into the sand of a Florida beach near Cape Canaveral. The shuttle needed to burrow deep enough that any passing humans wouldn’t see it while the aliens used it to spy on Earth’s space program. “From how high should I drop the shuttle so that it is hidden?” the commander asked their science advisor. The science advisor pulled out their alien high school mechanics book, hoping to calculate this based on the laws of motion and Earth’s gravitational force.
If you’ve ever worn soft contact lenses, you may know that they dry out and harden if they are not stored in a solution. This pervasive issue of hydrogel materials occurs when the solvent leaks or evaporates, affecting their mechanical properties. In this week’s post, polymer scientists develop super-soft dry elastomers (very elastic or rubbery polymers) that surpass the softness and elasticity of hydrogels, all without getting their hands wet.