A research group from the Institute of Advanced Study in Science and Technology (IASST) in India has developed ultra-thin heteroprotein films, which are designed to act as an alternative to isolated protein films.

Developed by the IASST’s physical sciences division, the films have thermal, mechanical and potential of hydrogen (pH) stability, which could expand the range of thin film applications in the biomedical and food packaging industries.

The monolayer protein films incorporate two globular proteins, namely bovine serum albumin (BSA) and lysozyme (Lys).

The researchers used the Langmuir-Blodgett technique, which gives the films’ thickness in nanometers (nm).

During their study, researchers looked for different structures and morphologies of the complex films in variable pH environments to understand their stability and associated properties.

India’s Science & Technology Ministry said in a press statement: “The complex formation between the two proteins occurred at a unique pH of 9.2 as a result of an electrostatic attraction along with hydrophobic interactions.

“This monolayer complex was formed at the air-water interface, which was later transferred to the silicon substrates at a surface pressure of 18 mN/m for further study.

“It was shown that the monolayers at the air-water interface can hold its intrinsic structure for a sufficiently longer period of time due to the complexation forming a highly stable film.”

The heteroprotein films are thinner than other protein or plastic films, as well as more flexible.

Films that feature the BSA and Lys complex proteins can be used to create highly stable biodegradable thin films of different protein complexes.

This helps expand the applications of these films in the area of thin-film technology.

In addition, physicochemical methods such as parameter alteration or incorporating fatty acids or polyol moieties into this protein complex cause the film to be free-standing, making it suitable for a range of applications.