Smart Hydrogels Eyed for Targeted Drug Delivery, Stem-Cell Therapy

Researchers in China have made a breakthrough in the development of materials for next-generation medical applications with the development of a new light-responsive, protein-based hydrogel.

Researchers in China have made a breakthrough in the development of materials for next-generation medical applications with the development of a new hydrogel that not only is made of organic proteins, but also responds to light.

A research team led by Prof Sun Fei, assistant professor of chemical and biological engineering at The Hong Kong University of Science and Technology (HKUST), created the so-called “smart” hydrogel, which is protein-based and light responsive. This combination of characteristics is what makes the hydrogel “smart,” Fei explained to Design News.

“Our hydrogels are entirely composed of recombinant proteins and therefore genetically programmable,” he said. “Also their biochemical and mechanical properties can be fine-tuned by light.”

hydro gel

Prof Sun Fei, assistant professor of chemical and biological engineering at The Hong Kong University of Science and Technology (HKUST), works in the lab with a new protein-based hydrogel developed by his team. The hydrogel has great potential for use in next-generation medical applications where synthetic materials are not viable. (Source: HKUST)

Hydrogels are also known as “soft matter” in the medical field, and researchers see them as materials that will lead next-generation applications in drug delivery and stem-cell therapy.

“In general, some physical properties (soft, high water content) of hydrogels resemble those of the human extracellular matrix, and the porous structure of hydrogels [can allow] a drug inside it [to be] released in sustained manner,” Fei said.

However, to date, the hydrogels currently being developed and used in products such as facial masks and contact lenses are comprised of either synthetic polymers or biomaterials like animal collagen, which can cause allergies. For this reason, they can’t fully mimic the complex biological environment needed for cell growth and development, so aren’t yet quite viable for applications for which researchers aim to use them.

The hydrogel developed by Fei’s team now changes that scenario because not only is it suitable to act as a carrier for stem cells that are the key components for regenerative medicine, but it also can control how and when a drug is delivered inside the human body due to its light-sensing function, he said.

“In our case, elastin-like proteins and adenosylcobalamin--the two major components of the hydrogel--have well-defined metabolic profiles in human body and should raise no concern regarding safety,” Fei said. “Our work demonstrated the feasibility of creating stimuli-responsive hydrogels by directly assembling protein molecules with the desirable responsiveness under mild conditions. We have been able to faithfully transfer the function of proteins at the molecular level to the material properties at a macroscopic level.”

The team created the hydrogel by assembling genetically engineered proteins into molecular networks by stitching together the photoreceptor C-terminal adenosylcobalamin binding domain proteins at room temperature, they said. As Fei noted, the composition of the resulting hydrogel resembles that of human tissues and thus can be used to deliver live cells into human bodies while potentially minimizing allergies and body rejection.

For the purpose of carrying drugs into the body, the hydrogel’s photo-responsive characteristic allows it to quickly switch from solid to liquid upon light exposure, which would allow medications to be released into the body in a controlled way, he added.

The team published a paper on their work in the journal PNAS. Researchers plan to continue their research by performing spectral tuning of the hydrogel through protein-directed evolution “to achieve near-infrared-light responsiveness of the material,” Fe said. They also plan to experiment with its use for insulin delivery, he added.

Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 15 years.