It is now possible to utilize silk inks containing growth factors, nanoparticles, antibodies, antibiotics and enzymes in inkjet printing, turning it into a new and more effective tool in bio-sensing, regenerative medicine and therapeutics, according to research led by biomedical engineers from Tufts University.

In a study printed in the journal Advanced Materials, researchers pointed out that inkjet printing is a highly accessible and immediate printing technology, but the heat-sensitive nature of biomolecules meant that they quickly lose their functionality when used in printing.

Enter fibroin, a purified silk protein that features protective properties and strength. Well-suited for optoelectronic and biomedical applications, fibroin functions like a "cocoon" that stabilizes compounds while conforming to many different formats.

"We thought that if were able to develop an inkjet-printable silk solution, we would have a universal building block to generate multiple ... formats ... [for] a wide variety of applications," said Fiorenzo Omenetto, Ph.D., associate dean for research at the Tufts School of Engineering and a senior author for the study.

Using the same base material, the researchers created and tested a library of functional silk inks laden with various compounds ready for printing with an inkjet printer. Some of the silk inks made would change color when exposed to certain bacteria and be a means for distributing antibiotics.

Specifically, the researchers envisioned the silk inks would be used on bio-sensing gloves that react to various pathological agents. For instance, imagine gloves printed with the word "contaminated." If there is indeed contamination, the ink would turn from blue to red to signify the exposure.

Then as a means of antibiotic distribution, the silk ink could be infused with medication and printed on bandages, creating a delivery system that can complement the type of injury being treated.

The current study only used one ink cartridge but the researchers believe it is possible to use several cartridges during printing to combine functions. It received funding support from the Air Force Office of Scientific Research and the Office of Naval Research and includes work from Hu Tao, David Kaplan, John Rogers, Benedetto Marelli, Serdar Onses, Miaomiao Yang and Bo An. Rogers and Onses were from the University of Illinois.

In the past, Omenetto and Kaplan have worked on exploring silk as a plastic alternative. According to his 2011 TED Talk, Omenetto referred to silk as a "new old material" which could have a dramatic impact in different technical fields.

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