Researchers established these aspects by varying the layer thickness of both types to enable interactions with specific wavelengths for the creation of light-activated theranostic nanoparticles.

With such a resource at their disposal, users can diagnose and verify size and placement of tumors, and administer heat as a form of treatment in the same hospital visit. Follow-up scans could then be employed to verify that the entire tumor was destroyed.


Halas’ team also developed a generic way for changing the type of metal by adding unloaded chelate molecules into the silica by soaking the particles in a bath of salts. The metals changed in the bath, enabling users to easily load different paramagnetic ions, including manganese, into the nanomatryoshkas with their final layer, an outer gold shell, added as a barrier to prevent ion leeching and to support plasmonics and fluorescent dyes added for dual-mode diagnostics.

"We are advancing both on optimizing the design of the iron chelate-containing nanoparticle for various applications that include both imaging and therapeutics," said Halas. "We are planning for addition in vivo trials and we are looking forward to the commercialization of this approach."

Research was based partially on a 2017 study which showed that gadolinium chelates could be embedded within the silica layer for MR contrast. Halas is the inventor of nanoshells, first developed more than twenty years ago at Rice.

Funding was provided by the J. Evans Attwell-Welch Fellowship program from Rice's Smalley-Curl Institute, the Robert A. Welch Foundation, the São Paulo Research Foundation, the National Cancer Institute and the National Institutes of Health.

The findings were published online in the American Chemical Society journal, ACS Nano.

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