Efficient nanoheater operated in a biological window for photo-hyperthermia therapy.

Ji Li,Kailei Lu,Hanyang Li,Jin Ren,Muhammad Khuram Shahzad,Lu Liu,Li Xu,Enming Zhao

doi:10.1364/boe.10.001935

Abstract

Remotely monitoring and regulating temperature in a small area are of vital importance for hyperthermia therapy. Herein, we report ~11 nm NaErF4 nanocrystal as the ultra-small nanoheater, which is highly safe for biological applications. Under 1530 nm photon excitation, upconversion intensity of NaErF4 is significantly enhanced as compared to the conventionally used 980 nm pumping source. Upconversion mechanisms are discussed on the basis of power dependence measurements. Importantly, light-to-heat transformation efficiency of NaErF4 through 1530 nm pumping is determined as high as 75%. Efficient NIR emission, centered at ~800 nm and thus within the biological window, is used for the temperature feedback. The potential applications of this highly efficient nanoheater for controlled photo-hyperthermia treatments are also demonstrated.

Highlights

Controlling and monitoring the temperature of small area are the fundamental preconditions for understanding and utilizing microscopic thermal processes, especially useful in some biological applications such as hyperthermia therapy [1]
NaErF4 nanocrystals are synthesized by a modified thermal decomposition method [32]
Such small size is highly useful for biological applications, due to small nanoparticles can efficiently penetrate subcellular membranes, can be cleared from the human body, and would be more suitable for ex vivo diagnostics [33]

Summary

Introduction

Controlling and monitoring the temperature of small area are the fundamental preconditions for understanding and utilizing microscopic thermal processes, especially useful in some biological applications such as hyperthermia therapy [1]. Nanoheaters with various compositions have been developed, including Au nanoshells, nanorods, and nanocages [12,13,14], Cu5S9 nanocrystals [15], Cu2-xSe nanoparticles [16], carbon nanoshells and naonotubes [17,18], graphene flakes [19], porous silicon [20] and so on. These nanoheaters have been proved to be efficient heat converter, lack of selfmonitoring of temperature requires additional component to send signal for the temperature readout. Excitation and/or emission wavelengths falling in the so-called biological windows (BW, including І-BW spinning 650-950 nm, ΠBW covering 1000-1350 nm and Ш-BW within 1500-1750 nm [27]) are developed [8,16,18]

Methods

Results

Conclusion