Photosensitizer properties of Ti3C2 MXene under continuous and pulsed regimens of the near-infrared laser

MXenes, a recently emerged class of 2D transition metal carbides/nitrides, have captured significant scientific interest due to their unique physicochemical properties. These properties offer promising avenues for various applications, including energy storage, water purification, sensors, catalysis and, recently, biomedicine. In particular, MXenes possess uniquely high light-to-heat energy conversion, and therefore they are promising as photosensitizers for non-invasive targeted photothermal therapy (PTT) to cancer treatment. However, there remain unresolved issues related to improving their functional performance, surface functionalities, biocompatibility and biodegradability. Our study aimed to determine and select the optimal laser parameters for PTT with Ti3C2 MXene on fibroblasts.

During the experiment, we investigated the modes of two types of infrared (IF) lasers: pulse and continuous, using Ti3C2 MXene at concentrations of 50 ug/ml, 25 ug/ml, 12.5 ug/ml, and 6.25 ug/ml. Human fibroblasts were used as target cells.  As a light source, we used a continuous laser with a wavelength of 940 nm (Lica-Surgeon, Photonics Plus LTD, Cherkasy, Ukraine) with an optical light source of 600 µm. Laser processing was carried out at a distance of 30 cm for 10 min at a power of 2 W and four different temporary installations (constant, pulsed with 500 ms ON/100 ms OFF, pulsed with 50 ms ON/50 ms OFF, pulsed with 100 ms ON/100 ms OFF) as well as at a power of 1 W with one temporary installation (constant). 

The results of the investigations demonstrated that irradiation at a power of 2 W pulsed (2W 500/100 pulse) and continuously (2W Constant) kills fibroblasts. During the experiment, we proved that the best and safest modes for a pulsed laser: power 2 W with various time settings (pulsed with 50 ms ON/50 ms OFF, pulsed with 100 ms ON/100 ms OFF) and for a constant laser: power 1 W.

Our research highlights the potential of combining photothermal therapy with MXene in cancer therapy.