Nanomaterial Design of Tungsten Disulfide for Near-Infrared-II Photothermal Cancer Therapy

Overview

Photothermal therapy (PTT) is a new therapeutic cancer treatment strategy that offers advantages to traditional cancer treatments, such as minimal invasiveness, higher specificity, and precise temporal selectivity. Optical imaging in the second near-infrared region (NIR-II, 1000-1350nm) has prospective applications in PTT and is superior to the first near-infrared region (650-1000nm). However, it proves challenging to find NIR-II materials. To resolve this, multiple elements were tested in substitutional doping to tune the bandgap of monolayer Tungsten Disulfide (WS2). Two-dimensional materials have long proved to offer various properties, with WS2 predicted to have ideal adjustable optical properties. Quantum density functional theory calculations revealed the band structure and optical spectra of the different doped monolayer WS2. The bandgap of monolayer WS2 was successfully tailored to activate absorption in the NIR-II region. Results show that Zirconium doped WS2 had a bandgap of 0.04 eV and Titanium doped WS2 had a bandgap of 0.06 eV, which was ideal for NIR-II. Doping with Zirconium or Titanium exhibits strong absorption in the NIR-II range with absorption coefficients of 18830 and 13314 cm-1, respectively, which is very competitive for PTT. This demonstrates the potential of these materials as NIR-II photothermal agents. Novel materials were created which prove the viability of NIR-II PTT, a possible future cure for cancer.