Tag Archives: adhesion


How you get Ingrown Toenails, explained by Science

Having a ingrown toenail could ruin your day and a lot after if you don’t have it fixed. Yet, even though ingrown nails and other nail-related conditions are common and pesky, very little is known about them. Now, a team at University of Nottingham have published a mathematical model that explains what forces are tugged beneath your finger nails and what exactly happens when this delicate interplay is upset. Of course, there’s a piece of practical advice: always trim your nails with the curve bits following a parabola.

A gruesome pain at your fingertips


The Greek physician Paul of Aegina was among the first to discuss surgical treatments for nail conditions in the 7th century, but humans have been forced to live with annoying pain long before. To understand how ingrown nails come to be, we first need to discuss, however, how nails are formed and what causes them to grow and pop from under your skin.

Basically, nails are nothing but dead skin cells coated with a hardening protein called keratin that stick out from the half-moon-shaped “lunula” at the base of the nail toward the fingertip. On average, fingernails grow by 0.1 to 0.2 millimeters per day, but it’s no smooth sailing. Keeping the nail in place are adhesive molecules behave like ratchets: They grab onto the nail above them, and as the nail slides forward during growth, they tilt and stretch, trying to hang on, until eventually the bond breaks. Once this happens, the molecules just attach themselves to another piece of nails.

Sometimes, though, the balance between nail growth and adhesion is interrupted. When this happens, the nail might change shape to compensate and end up in all the wrong places – like under your skin and into live flesh!

“We have discovered that three well-known conditions– ingrown nails, pincer nails, and spoon-shaped nails — are essentially three faces of the same coin,” says Cyril Rauch, lead author on the new paper. “They are related by the physics.”

“Ingrown nails, pincer nails, and spoon-shaped nails are essentially three faces of the same coin.”

Ingrown toenails happen when the nail extends into the flesh alongside the nail. Kids, teenagers, and pregnant women are among the most vulnerable because raging hormones are causing the nail’s growth to outpace adhesion, according to the University of Nottingham model. Pincers result from the opposite problem. In this condition, the sides of the nail curve down and towards each other, forming a “C” shape. Rauch’s model suggests that in this condition, adhesion overpowers growth, which may explain why pincers are more commonly found in the elderly, whose growth is slower.

How to stop ingrown nails

Overall, nail problems are predominantly caused by biological factors that are outside our control, yet with proper hygiene, it’s possible to minimize the risk of ingrown or pincer nails. Here’s the best way to trim your nails:

“Imagine you can flatten your nail out on your desk,” says Rauch. “The curved bits should follow a parabola shape.”

If you’re having an ingrown toenail (the most common sort), here’s what you can do:

  • Soak your foot in a mixture of hot (or as hot as you can stand it) water and Epsom salt. Do this for 15-30 minutes at least twice daily. The goal here is twofold: to soften the toenail and prevent the ingrown nail from becoming infected.
  • Trim your toenail, taking extra care around the ingrown section. Make sure your toenail is cut perfectly straight without any pointed parts near the edges. Toenails that are rounded off have an increased likelihood of growing into the skin, causing ingrown nails.
  • Keep your toenail slightly raised. Putting a small piece of cotton between your toenail and the skin should keep the ingrown toenail from coming back. Remove the cotton daily to prevent infections.
  • In fact, you should apply infection-preventing ointment to the site and keep it bandaged. Neosporin works fine for these purposes.
  • Don’t wear socks or shoes, at least when you’re at home.

Rauch is actually a veterinarian and is currently adapting the model for animals, where nail health is a big problem and can cause serious financial deficits.

“When animals develop hoof problems, it costs a lot of money,” says Rauch. It turns out the horse hoof is actually pretty similar to the human nail. “The main difference, of course, is that the horse walks on its nail and the human doesn’t, so we need to add that new stress to the model.”

The findings were reported in the journal Physical Biology. [via PopSci]

strongest underwater glue

Underwater glue inspired by shellfish might help repair ships

strongest underwater glue

Shown here is the adhesion between the silica tip of an atomic force microscope and adhesive fibers made by fusing mussel foot proteins and curli amyloid fibers.(Photo : Pixabay)

Taking inspiration from nature, scientists at MIT have engineered a new sort of glue that acts like a powerful adhesive even in underwater conditions and can cling on to virtually any surface, be it metal or organic. The glue might prove to be useful to repair ships or seal wounds and surgical incisions.

The strongest underwater glue to date

Shellfish like mussels and barnacles are a familiar sight to seamen since they’re often found by the thousands clinging to rocks or ship hulls. They hold on tightly even through the worse of storms and can be very difficult to detach, much to the exasperation of the maintenance crew. This uncanny ability is made possible by very sticky proteins secreted by such animals, called mussle foot protein

[ALSO READ] Making a novel glue out of gold

Previously, scientists engineered E. coli bacteria to produce the same proteins, however the resulting matter wasn’t nearly as adhesive. This time, the MIT engineers took an alternate route; while they engineered the same E. coli bacteria to secret these proteins, they were also careful to add and activate genes that produce curli fibers. Curl fibers are fibrous proteins that can naturally join together and self-assemble into much larger, more complicated compounds. More familiarly, the fibers join to form a biofilm – slimy layers formed by bacteria growing on a surface.

Two experiments were made where curli fibers bonded to either mussel foot protein 3 or mussel foot protein 5.After purifying these proteins from the bacteria, the researchers let them incubate and form dense, fibrous meshes. The resulting material has a regular yet flexible structure that binds strongly to both dry and wet surfaces.

“The result is a powerful wet adhesive with independently functioning adsorptive and cohesive moieties,” says Herbert Waite, a professor of chemistry and biochemistry at the University of California at Santa Barbara who was not part of the research team. “The work is very creative, rigorous, and thorough.”

The team tested the resulting matter with atomic force microscopes – a technique for analyzing the surface of a rigid material all the way down to the level of the atom. AFM uses a mechanical probe – the tip – to magnify surface features up to 100,000,000 times, and it produces 3-D images of the surface.The researchers found that the adhesive bonded strongly to different types of materials, using three tips for the microscope: silica, gold, and polystyrene. Adhesives assembled from equal amounts of mussel foot protein 3 and mussel foot protein 5 formed stronger adhesives than those with a different ratio, or only one of the two proteins on their own.

The researchers report the resulting adhesive is actually stronger than naturally occurring mussel adhesives and that it’s the strongest protein-based glue designed to work underwater, reported to date. Findings appeared in the journal Nature Nanotechnology.