Recently, molybdenum disulfide (MoS2) sheet, ultrathin two-dimensional layered materials, has received significant attention as an efficient PT agent due to its high optical absorbance, large surface area and photo-corrosion resistance. Therefore, many studies have focused on the use of PT energy of MoS2 sheet in therapeutic applications through tissue ablation and modulated drug release. However, little attention has been paid to real-time thermal imaging of MoS2 sheet, which is essential to avoid undesired overheating within a target material and to understand thermodynamics around MoS2 during PT heat generation. Conventional thermal imaging methods require expensive detectors and often have limited resolution. In addition, these methods typically can be used in gas phase so that it is important to find the methods for the real-time sensing in aqueous and organic phases like environmental condition. In this regard, we developed novel self-monitoring photothermal (PT) agents using opto-thermally responsive block copolymer-MoS2 composites (BCP-MoS2), which enabled simultaneous PT heating and imaging of temperature profiles. In particular, upon near-infrared light exposure, PT energy from MoS2 successfully increased local temperature and induced thermally activated conformational transitions of the BCP on MoS2. This led to fluorescent signal changes caused by distant-dependent Förster resonance energy transfer between the BCP and MoS2. Importantly, we demonstrated that the use of BCP-MoS2 for PT heating and optical mapping was fully reversible with excellent stability. The detailed mechanism of the responsive behavior of BCP-MoS2 was elucidated by measurements of time-resolved fluorescence and dynamic light scattering. In addition, our BCP-MoS2 system was integrated into organogel matrices to demonstrate its potential as portable, self-monitoring PT system suitable for biological and environmental applications.

Fluorescent block copolymer-MoS2 nanohybrids for real-time photothermal heating and imaging

253rd National Meeting (2017)

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