MIT microparticles deliver phototherapy and chemotherapy

04 Nov 2024

Multimodal light-activated cancer therapy would benefit patients in need of recurring treatments.

A project at MIT has developed microparticles able to be implanted at a tumor site and deliver two types of therapeutic treatment.

As reported in ACS Nano, the particles enable both chemotherapy and phototherapy to be applied to a malignancy, potentially reducing the side effects that can occur when chemotherapy is employed alone.

Current approaches to phototherapy in clinical trials make use of nanoparticles implanted adjacent to cancer cells and which then emit heat when exposed to infra-red light.

This has usually involved gold or gold-encased nanoparticles, and the approach has made steady progress towards clinical translation since being conceived some years ago. Recent trials have confirmed the potential value of the technology for conditions such as prostate cancer.

MIT wanted to come up with a way to deliver not just phototherapy but also chemotherapy in the same procedure, since this would make the treatment process easier on the patient and might prove to have synergistic effects as a cancer therapy.

"One of the examples where this particular technology could be useful is trying to control the growth of really fast-growing tumors," said Ana Jaklenec from the Koch Institute for Integrative Cancer Research at MIT.

"The goal would be to gain some control over these tumors for patients that don't really have a lot of options, and this could either prolong their life or at least allow them to have a better quality of life during this period."

A game-changer for treatment options

The system developed by MIT uses not gold microparticles but molybdenum disulphide nanosheets, combined with either doxorubicin, a hydrophilic chemotherapy drug, or violacein, a hydrophobic drug. Manufacturing the final particles involved turning molybdenum disulphide and the chosen chemotherapeutic into a film that can be pressed into microparticles of different shapes and sizes.

For its proof of concept study, MIT created cubic particles with a width of 200 microns that can remain present at a tumor site throughout a treatment program once injected. During each treatment cycle, an external near-infrared laser was used to heat up the particles, penetrating to a depth of a few millimeters to centimeters.

"The advantage of this platform is that it can act on demand in a pulsatile manner," commented MIT's Maria Kanelli. "You administer it once through an intratumoral injection, and then using an external laser source you can activate the platform, release the drug, and at the same time achieve thermal ablation of the tumor cells."

In trials applying the system to model breast cancer cells in mice subjects, the researchers implanted 25 microparticles per tumor and then performed the laser treatment three times, with three days in between each treatment.

Results showed that this treatment regime completely eradicated the tumors, and the mice lived much longer than those that were given either chemotherapy or phototherapy alone, or no treatment at all. Mice that underwent all three treatment cycles also fared much better than those that received just one laser treatment.

"This is a powerful demonstration of the usefulness of near-infrared-responsive material systems,” said Angela Belcher of MIT. "Controlling the drug release at timed intervals with light, after just one dose of particle injection, is a game-changer for less painful treatment options and can lead to better patient compliance."