Phase-controlled synthesis of molybdenum oxide nanoparticles for surface enhanced Raman scattering and photothermal therapy

Abstract

Different from their bulk counterparts, plasmonic molybdenum oxide nanomaterials display superior optical and electronic properties, but unfortunately, phase-controlled synthesis of molybdenum oxide nanomaterials with multifunctional performances still remains a challenge. To actualize this, a surfactant-free solvothermal strategy was proposed to fabricate molybdenum oxide nanomaterials with a tunable phase. Encouragingly, the as-prepared molybdenum dioxide nanoparticles (MoO2 NPs) exhibit intense near-infrared (NIR) absorption attributed to the localized surface plasmon resonance (LSPR) effect, which results in their application as a surface enhanced Raman scattering (SERS) substrate to detect trace amounts of molecular species including Rhodamine 6G (R6G), crystal violet (CV), IR-780 iodide (IR780) and methylene blue (MB). The detection limit was as low as 5 × 10-8 M and the maximum enhancement factor (EF) was up to 1.10 × 107, compared to other semiconductor nanostructures, the SERS sensitivity may be the best. Meanwhile, with the significant photothermal conversion efficiency up to 61.3%, the plasmonic MoO2 NPs could also be used as a photothermal therapy (PTT) agent for efficient photothermal ablation of cancer cells in vitro.

Insights into the deep-tissue photothermal therapy in near-infrared II region based on tumor-targeted MoO2 nanoaggregates

“…However, most of the reported TMOs suffer from relatively low photothermal conversion efficiencies (PTCEs) in NIR-II region. As an emerging type of NIR plasmonic semiconductor, oxygen-deficient molybdenum oxides (MoO x , 2 ≤ x < 3) have seen a remarkable burst of interest due to the lowcost synthesis, tunable band gap and pH-dependent oxidative degradation [26][27][28]. For example, Yin et al [29] synthesized small-sized MoO x nanoparticles with a wide light absorption from 600 to 1200 nm using the facile hydrothermal method.…”

Synergistic Chemo-Photothermal Suppression of Cancer by Melanin Decorated MoOx Nanosheets

“…IR spectra are presented in Figure 3a. The peaks at 640 and 880 cm -1 in the spectrum of MoOx correspond to Mo-O-Mo vibrations, and there is additionally a band at 950 cm -1 from Mo=O [37][38][39][40][41] . CH2 vibrations can be seen at around 2950 cm -1 and 1450 cm -1 from the oleylamine in the system.…”

Advanced Near‐Infrared Light‐Responsive Nanomaterials as Therapeutic Platforms for Cancer Therapy

“…This was further confirmed in Panc-1 xenografted mice model. [259] By increasing the reaction duration, MoO 2 , MoO 3-x , and MoO 3 with varying optical properties were obtained. It was observed that mice treated with 1064 nm exhibited the smallest tumor size post-treatment, indicating the better synergistic PDT and PTT effect by 1064 nm excitation ( Figure 27E).…”