September 30, 2017 | David F. Coppedge

Cells Teach Humans About Design

Biomimetics extends to the cellular level, where extraordinary processes show engineers the right way to do things.

Locks and keys. We all know man-made locks on our doors, but cells use lock-and-key mechanisms to regulate their own processes. says that “Copying nature’s lock-and-key system could improve rapid medical diagnostics.” Researchers at Imperial College London looked at the secrets of receptors on proteins to fashion a new kind of transistor.

Receptors recognise molecules with particular shapes and bind to them in a lock-and-key mechanism. In this study, the nanoscale transistor was made from a polymer material that could be imprinted with a binding site – ‘the lock’. This allows the system to detect the only matching ‘key’ – a specific target molecule.

To test that the system works as expected, the team used it to detect the antibody that binds to insulin, a mechanism important in the diagnosis of diabetes. However, the team say that the system design can also be readily applied in the detection to a much broader range of biological molecules.

Co-author of the study Professor Joshua Edel, from the Department of Chemistry at Imperial, said: “We have shown that we can imprint a polymer at the entrance to the nanopore with the shape of the natural ‘lock’ to the ‘key’ molecule we are looking for, mimicking biological receptors.

What’s a ‘photonic melanin supraball’? Whatever it is, it must be good, because it was the product of ‘bioinspiration’ to a team desiring to mimic structural colors – those ‘photonic crystals’ that give butterflies their iridescent wings and birds their flashing feathers. To achieve their design, they looked to the molecular components behind those animal wonders:

We demonstrate a feasible solution for producing structural colors inspired by bird feathers. We have designed core-shell nanoparticles using high–refractive index (RI) (~1.74) melanin cores and low-RI (~1.45) silica shells. The design of these nanoparticles was guided by finite-difference time-domain simulations. These nanoparticles were self-assembled using a one-pot reverse emulsion process, which resulted in bright and noniridescent supraballs. With the combination of only two ingredients, synthetic melanin and silica, we can generate a full spectrum of colors. These supraballs could be directly added to paints, plastics, and coatings and also used as ultraviolet-resistant inks or cosmetics.

Think of the lipstick shades that could come from this technology. Even pigs might look charming with it.

Selective passage for smart membranes. Cell membranes have the amazing capacity to let certain items in and block others. Called active transport, this capacity (unlike unguided osmosis, a natural law that only follows the concentration gradient), allows cells to use natural law to ‘violate’ natural law by design, going against natural concentration gradients through the use of highly-sophisticated ‘gates’ in the membrane. One of those is the aquaporin family of membrane channels, which let water in or out but can block other molecules. Nature Scientific Reports published a new paper about this, “Quantification of Aquaporin-Z reconstituted into vesicles for biomimetic membrane fabrication.” This is important, they say, because “Aquaporin incorporated biomimetic membranes are anticipated to offer unprecedented desalination capabilities” such as reverse osmosis.

Quantifying the reconstituted aquaporins in synthetic membranes, however, represents a “huge hurdle” to progress in this field. The team in Singapore came up with a new method to determine how many channels make it into production:

These methods allow more accurate determination of Aquaporin-Z reconstituted and loss during reconstitution, with relatively commonly available equipment and without complex sample handling, or lengthy data analysis. These would allow them to be widely applicable to scientific studies of protein function in the biomimetic environment and engineering studies on biomimetic membrane fabrication.

In this series of three CEH articles, we have shown that biomimetics is still a very hot topic in science. Engineers are getting inspired everywhere in nature: from animals, from plants, and even from the tiny molecular machines in cells.

Go bioneers! (5/13/06). In the 15 years we have been reporting on progress in biomimetics, interest in the subject has grown steadily around the world. The time is ripe to oust the Darwin Party totalitarian regime and send them into exile. Design is the word for the 21st century!



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