Injectable self-healing gel provides long-term drug delivery

The new hydrogel type can be seen in these electron microscopy images, which show the nanogel and polymer structure at different magnifications (Image: MIT)

A team of MIT researchers has developed a new, self-healing hydrogel that doesn’t require surgical implantation, but can be injected using a syringe. The new gel, which can carry two drugs at once, allows for more convenient treatment of numerous conditions.

Using gel as a method of drug delivery can allow for greater versatility than traditional liquid solutions. Gels can be molded into specific shapes, can be used to deliver treatment over extended periods of time and, thanks to their static nature, can provide treatment targeted at specific tissue. However, conventional methods of treatment using gel require the patient to undergo surgery, meaning it’s not always a convenient option.

A team of MIT scientists has tackled the issue by developing a new hydrogel that has the ability to heal itself, allowing it to be administered using a syringe. The method has the potential to be useful in the treatment of a wide range of conditions, including heart disease and cancer.

While existing hydrogels, such as those used to create soft contact lenses, cannot have their shape easily altered once formed, the new gel combines two separate polymers with weaker linkages that can be broken and reformed.

The gel is constructed from PEG-PLA polymer nanoparticles combined with strands of another polymer – in this case, cellulose. The polymer chains form weak bonds with multiple nanoparticles, creating a lattice of nanoparticles and polymers that easily break apart when stress is applied. Once the stress is over, the gel is healed through the formation of new bonds.

Aside from its heightened practicality, the new gel allows for the delivery of two drugs at once. The PEG-PLA nanoparticles can carry hydrophobic small-molecule drugs – such as those used in chemotherapy – at their cores, while the partnering polymers can be used to administer hydrophilic molecules such as antibodies and proteins. The properties of each component of the gel can be fine-tuned so that they release their payloads at different rates.

During the study, the gel was injected under the skin of mice, after which it successfully delivered two drugs over a period of several days.

The team believes the method could be ideal for various uses including repairing tissue after a heart attack and delivering cancer drugs to kill tumor cells left behind after surgery. It’s now working to adapt the technique for macular degeneration treatment, which requires regular injections into the patient’s eye. It’s believed that the use of gel could significantly lower the frequency of injections, making it easier to cope with the condition.

Source: MIT

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