Even with pre-operative imaging techniques, surgeons still rely on visual inspection to locate malignant tissues during surgery.

New research released today at the 2017 American Association of Pharmaceutical Scientists (AAPS) Annual Meeting and Exposition may help surgeons better view and treat these tumour cells with engineered naphthalocyanine-based nanoparticles (SiNc-PNP) injected 24 hours before surgery, which then light up when they connect with the cancerous tumours.

In the study, researchers developed an activatable theranostic nanoplatform that can be used for two purposes: tumour delineation with a real-time near-infrared (NIR) fluorescence signal during surgery, and an intraoperative targeted treatment to further eliminate hard-to-remove tumours by non-toxic phototherapy.

"You can relate these nanoparticles like a light switch, they are off until the tumour cells turn them on," said the study's lead researcher Oleh Taratula, Ph.D., assistant professor of pharmaceutics, Oregon State University. "Tumour cells can be close to healthy tissue, blood vessels and more, making them challenging to remove. The surgeon can shine the near-infrared light on the now-glowing cells and these nanoparticles will absorb the light transferring it to a heat to eliminate the tumour cells."

The developed nanoparticles were successfully delivered to, accumulated at, and even penetrated into the core of tumours in animal models.

Subsequently, these activatable SiNc-encapsulated polymeric nanoparticles turned on the NIR fluorescence at the tumor site, offering high cancer-to-tissue contrast imaging.

The feasibility of activatable SiNc-PNP in the application of real-time intraoperative image-guided surgery was demonstrated using Fluobeam® 800, an FDA-approved intraoperative NIR imaging system, during which sensitive fluorescence detection of cancer tumours was observed for tumour resection.

Phototherapy during surgery in mice demonstrated successful removal of the subcutaneous tumour guided by the fluorescence signal from SiNc.

The NIR light was shone on the tumour 24 hours after injection (10 minutes) of the nanoparticles.

Chemoresistant tumours, when treated with this single dose of phototherapy, were completely eradicated from the mice, with no tumour recurrence detected during the experiment.

Taratula added, "We think these nanoparticles could be a powerful diagnostic and treatment tool to enhance surgical outcomes and patient prognosis for a variety of cancers in the future."

The next step for the researchers is to confirm the efficacy of the phototheranostic nanoplatform by conducting image-guided surgery in combination with phototherapy in additional animal models.

Source:  American Association of Pharmaceutical Scientists