Gel Nano-Capsules Could Be More Effective for Targeted Therapies

Gel nano-capsules with 2 shells keep drug molecules safe in transit.

In a new study, researchers created a gel nano-capsule with a double shell that can be used as a drug carrier for targeted therapies.

Other researchers have been working on these drug carrier systems for some time, keeping the drugs contained before reaching the right place in the body is a major issue, according to the study published in Scientific Reports.

“Many existing carriers encapsulate drugs through the long-range electrostatic interactions, the carrier attracts oppositely charged medicine. Our method does not deal with the electrostatics at all,” said study co-author Igor Potemkin, PhD. “Filling in the nanogel by the guest molecules, locking them in the cavity and further release are controlled by the temperature. Therefore, the medicines themselves can be both charged and neutral.”

Researchers said that other tools to trigger the release of drugs, such as external magnetic field and pH exist, but efficiency of the drug release is a problem.

The gel nano-capsules used in the current study lose colloidal stability when loading the drugs, which makes delivery ineffective or even impossible. Researchers were able to remedy this problem by creating a carrier whose inner cavity is surrounded by 2 membranes of different chemical structures.

According to the study, the outer porous shell has a stabilizing role and stops aggregation of the nano-capsules and the inner shell can open or close dependent upon temperature from variable interactions between its monomeric units. The outer shells are synthesized around a silica core that gets chemically dissolved at the end of synthesis.

When the nano-capsules are filling, the pores of both shells are open and the nanogel absorbs the drug molecules. The temperature then changes and the inner shell closes its pores and locks the drug inside. The pores open and let the molecules out in places where the temperature allows.

Researchers found on the journey to the therapeutic destination, the drug molecules were almost completely safe and the inner cavity was stable in shape, which was larger than the initial size of the silica core.

“There are still many questions. For example, we have ‘caught’ a structure in which a cavity does not collapse as the pores are closed,” Dr Potemkin concluded. “Now we need to understand why it happens, how does the density of the layers' crosslink effect, ie, what is the minimum amount of crosslinker that does not lead to a collapse of the cavity, and so on. "