A research group from the physical sciences division of the Institute of Advanced Study in Science and Technology (IASST), Guwahati, an autonomous institute under the Department of Science and Technology, has successfully developed ultrathin heteroprotein film that could be used as an alternative to isolated protein films. Unlike other protein and plastic films, these ultrathin heteroprotein films are much thinner- in the order of a nanometer.
Scientists developed these films using two globular proteins: bovine serum albumin (BSA) and lysozyme (Lys). Using a technique called Langmuir-Blodgett (LB) technique to give the film the desired thickness. The relatively thicker film is formed at a pH of 9.2, where the complex formation is maximum.
Because it holds excellent thermal, mechanical, and pH stability, scientists think the films could have applications in the biomedical and food packaging industries.
Dr. Sarathi Kundu, Associate Professor, and Mr. Raktim J. Sarmah, SRF, a Ph.D. student, constructed a monolayer heteroprotein film, the first of its kind, utilizing this technology. They explored these complex films’ different structures and morphologies at variable pH conditions to explore their stability and related properties.
Electrostatic attraction and hydrophobic interactions resulted in the complex formation between the two proteins at a pH of 9.2. This monolayer combination was generated at the air-water interface and then transferred to silicon substrates under 18 mN/m surface pressure for further investigation. It was discovered that monolayers at the air-water interface could maintain their intrinsic Structure for a long time, thanks to the complexation forming a highly stable film.
Scientists noted, “Films of such protein complex of BSA and Lys can be useful for fabricating highly stable biodegradable thin films of different protein complexes for expanding its applications in thin-film technology. Diverse physicochemical methods such as parameter alteration or incorporation of different fatty acids or polyol moieties (glycerol, starch, gelatin, etc.) into this protein complex can make the film free standing for diverse applications.”
- Raktim J. Sarmah, Sarathi Kundu, et al. Structure and morphology of bovine serum albumin–lysozyme (BSA–Lys) complex films at air-water interface. DOI: 10.1016/j.foodhyd.2022.107788