Centre for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University, 510006 Guangzhou, China.
Nanoscale. 2019 Jan 23;11(4):1563-1569. doi: 10.1039/c8nr08986h.
Multi-photon upconversion super-resolution microscopy is a recently proposed imaging modality, based on lanthanide-doped nanocrystals, which can emit visible emission upon low-intensity near-infrared excitation. This imaging modality exhibits many advantages, including increased imaging depth, high signal-to-noise ratio, low phototoxicity, and high photostability. However, two factors seriously restrict its scanning speed, sometimes even to an intolerable degree; the long lanthanide emission lifetime and the low brightness. For proper imaging, pixel dwell times of several milliseconds are often required. In this work, a facile strategy is proposed to overcome these two obstacles. By adopting a high sensitizer (Yb3+) doping strategy for upconversion nanocrystals, their emission intensity is greatly increased and their emission transients are significantly accelerated, without losing the emission depletion efficiency induced by the depletion laser. This enables the implementation of a very fast upconversion stimulated emission depletion super-resolution microscopy with a scanning speed of 10 μs per pixel. This work opens the possibility for upconversion super-resolution microscopy to capture vital biological activities in real time.
多光子上转换超分辨显微镜是一种新兴的成像模式，基于镧系掺杂纳米晶体，在低强度近红外激发下可发出可见光。这种成像模式具有许多优点，包括增加成像深度、高信噪比、低光毒性和高光稳定性。然而，有两个因素严重限制了它的扫描速度，有时甚至达到了无法容忍的程度；长的镧系元素发射寿命和低的亮度。为了进行适当的成像，通常需要几毫秒的像素停留时间。在这项工作中，提出了一种简单的策略来克服这两个障碍。通过采用高敏化剂（Yb3+）掺杂策略来增加上转换纳米晶体的发射强度，并显著加速其发射瞬变，同时不损失由耗尽激光引起的发射耗尽效率。这使得实施非常快速的上转换受激辐射损耗超分辨显微镜成为可能，其扫描速度为每个像素 10 μs。这项工作为上转换超分辨显微镜实时捕捉生命活动提供了可能。
