PEGylated MoSe₂ Nanomaterials with Limited Oxidation via Femtosecond Laser Ablation for Photothermal Therapy

MoSe 2 nanomaterials are promising photothermal agents for noninvasive cancer treatment. Their surfaces usually need to be functionalized with biocompatible polymers to improve their biocompatibility and colloidal stability and to reduce their cytotoxicity. Herein PEGylated MoSe 2 nanomaterials are produced by femtosecond laser ablation of MoSe 2 powder in aqueous poly(ethylene glycol) (PEG) solutions. Quantum dots are produced by laser ablation for 30 min with a power of 1.5 W, while larger spherical nanoparticles are produced by laser ablation for 10 min with various powers. PEG molecules attach to the nanomaterials through both physical absorption and Mo–O chemical bonds. A higher concentration of PEG in the solution results in more PEG being attached, and increasing the laser ablation power leads to more PEG molecules being attached through chemical bonds. Notably, the attachment of PEG to the nanomaterials through Mo–O bonds can efficiently suppress the oxidation of the MoSe 2 nanomaterials to MoO 3 nanoparticles. Both the MoSe 2 quantum dots and spherical nanoparticles demonstrate high photothermal conversion efficiencies (PTCEs), and the PTCEs of the quantum dots are overall higher than those of the nanoparticles, making them a promising candidate agent for photothermal cancer therapy.