Targeted nanoparticles are used for treating cancer by controlling from outside of the body using near-infrared (NIR) light as stimulus.  NIR is used because it is minimally absorbed by skin and tissue, has the ability to penetrate deep tissue in a non-invasive way and the energy from NIR light can be converted to heat by gold nanomaterials for effective thermal ablation of diseased tissue.
Development
Researchers from Brigham and Women's Hospital (BWH) researchers have used self assembled, multi-functional, NIR responsive gold nanorod to deliver a chemotherapy drug targeted to cancer cells for selective release of the drug. This is made possible in response to an external beam of light to create heat for synergistic thermo-chemo mediated anti-tumor efficacy.
Researchers claim that the design of this gold nanorod and its self-assembly was inspired by nature and the ability of complimentary strands of DNA to hybridize on their own without imposing complicated chemical processes on them. Each functionalized DNA strand individually, and the self assembled components as a system, play a distinct yet integrative role resulting in synergistic targeted and triggered thermo-chemotherapy capable of eradicating tumors.
Functional components
According to the lead researcher, the platform is comprised of three distinct functional components and each plays a role in contributing to the triple punch of triggered thermotherapy, controlled doxorubicin release, and cancer cell targeting.
Function
One DNA strand is attached to the gold nanorod and the complementary strand is attached to a stealth layer and a homing molecule that keeps the system under the radar of the immune system while targeting it directly to cancer cells. When the DNA strands come together, the targeted gold nanorod is formed and the double stranded DNA serves as the scaffold for binding the chemotherapy drug, doxorubicin, which can be released in response to NIR light that concurrently results in generation of heat by the gold nanorods.
Treatment
Normally thermal ablation is used in cancer treatment, but in this method cancer cells are selectively targeted and hit twice, first with a controlled release of a chemotherapy drug and then secondly with triggered induction of heat from the activation of the gold nanorod,  all noninvasively. During the treatment tumors are irradiated using NIR light to activate the nanoparticle using the gold nanorod and created heat so that delivered heat and anti-cancer drugs synergistically eradicated tumors.