Researchers from Tel Aviv University (TAU) have created a new type of glass that is both highly adhesive and perfectly transparent at the same time. The glass, which forms spontaneously when the new material comes in contact with water at room temperature, could bring about a revolution in an array of diverse industries such as optics and electro-optics, satellite communication, remote sensing, and biomedicine.

The glass was developed by a team of researchers from Israel and around the world, led by PhD student Gal Finkelstein-Zuta and Professor Ehud Gazit from the Shmunis School of Biomedicine and Cancer Research at the George S. Wise Faculty of Life Sciences and the Department of Materials Science and Engineering at the Faculty of Engineering at TAU. The results of the research were published on June 12, 2024, in the journal Nature.

“In our laboratory, we study bio-convergence and specifically use the wonderful properties of biology to produce innovative materials,” explains Professor Gazit. “Among other things, we study sequences of amino acids, which are the building blocks of proteins. Amino acids and peptides have a natural tendency to connect to each other and form ordered structures with a defined periodic arrangement, but during our research, we discovered a unique peptide that behaves differently from anything we know: it didn’t form any ordered pattern but an amorphous, disordered pattern that describes glass.”

At the molecular level, glass is a liquid-like substance that lacks order in its molecular structure, but its mechanical properties are solid-like. Glass is usually manufactured by rapidly cooling molten materials and “freezing” them in this state before they are allowed to crystallize, resulting in an amorphous state that allows unique optical, chemical, and mechanical properties alongside qualities like durability, versatility, and sustainability. The TAU researchers discovered that the aromatic peptide, which consists of a three-tyrosine sequence (YYY), forms a molecular glass spontaneously upon evaporation of an aqueous solution under room-temperature conditions.

“The commercial glass we all know is created by the rapid cooling of molten materials, a process called vitrification,” says Finkelstein-Zuta. “The amorphous liquid-like organization should be fixed before it arranges in a more energy-efficient way as in crystals, and for that energy is required — it should be heated to high temperatures and cooled down immediately.

“On the other hand, the glass we discovered, which is made of biological building blocks, forms spontaneously at room temperature without the need of energy such as high heat or pressure. Just dissolve a powder in water, just like making kool-aid, and the glass will form.

“For example, we made lenses from our new glass. Instead of undergoing a lengthy process of grinding and polishing, we simply dripped a drop onto a surface, where we control its curvature — and hence its focus — by adjusting the solution volume alone.”

The properties of the innovative glass from TAU are unique in the world and even contradict each other: it is very hard, but it can repair itself at room temperature; it is a strong adhesive; and it is transparent in a wide spectral range, ranging from the visible light to the mid-infrared range.

“This is the first time anyone has succeeded in creating molecular glass under simple conditions.” says Professor Gazit, “But more important than that are the properties of the glass we created. It is a very special glass. On the one hand, it is very strong and on the other hand, very transparent — much more transparent than ordinary glass. The normal silicate glass we all know is transparent in the visible light range, but the molecular glass we created is transparent deep into the infrared range.

“This has many uses in fields such as satellites, remote sensing, communications, and optics. It is also a strong adhesive, it can glue different glasses together, and at the same time it can repair cracks that are formed in it. It is a set of properties that does not exist in any glass in the world, which has great potential in science and engineering, and we got all this from a single peptide: one little piece of protein.”