Sreenan Benjamin, Lee Bryan, Wan Li, Zeng Ruosheng, Zhao Jialong, Zhu Xiaoshan
Department of Electrical and Biomedical Engineering, University of Nevada-Reno, Reno, Nevada 89557, United States.
Department of Physics, Wenzhou University, Wenzhou 325035, China.
ACS Appl Nano Mater. 2022 Dec 23;5(12):17413-17435. doi: 10.1021/acsanm.2c04337. Epub 2022 Nov 30.
Colloidal semiconductor nanocrystals (NCs) have been developed for decades and are widely applied in biosensing/imaging. However, their biosensing/imaging applications are mainly based on luminescence-intensity measurement, which suffers from autofluorescence in complex biological samples and thus limits the biosensing/imaging sensitivities. It is expected for these NCs to be further developed to gain luminescence features that can overcome sample autofluorescence. On the other hand, time-resolved luminescence measurement utilizing long-lived-luminescence probes is an efficient technique to eliminate short-lived autofluorescence of samples while recording time-resolved luminescence of the probes for signal measurement after pulsed excitation from a light source. Despite time-resolved measurement being very sensitive, the optical limitations of many of the current long-lived-luminescence probes cause time-resolved measurement to be generally performed in laboratories with bulky and costly instruments. In order to apply highly sensitive time-resolved measurement for in-field or point-of-care (POC) testing, it is essential to develop probes possessing high brightness, low-energy (visible-light) excitation, and long lifetimes of up to milliseconds. Such desired optical features can significantly simplify the design criteria of time-resolved measurement instruments and facilitate the development of low-cost, compact, sensitive instruments for in-field or POC testing. Mn-doped NCs have recently been in rapid development and provide a strategy to solve the challenges faced by both colloidal semiconductor NCs and time-resolved luminescence measurement. In this review, we outline the major achievements in the development of Mn-doped binary and multinary NCs, with emphasis on their synthesis approaches and luminescence mechanisms. Specifically, we demonstrate how researchers approached these obstacles to achieve the aforementioned desired optical properties on the basis of the progressive understanding of Mn emission mechanisms. Afterward, we review representative applications of Mn-doped NCs in time-resolved luminescence biosensing/imaging and present the potential of Mn-doped NCs in advancing time-resolved luminescence biosensing/imaging for in-field or POC testing.
胶体半导体纳米晶体（NCs）已经发展了几十年，并广泛应用于生物传感/成像领域。然而，它们的生物传感/成像应用主要基于发光强度测量，这种方法在复杂生物样品中会受到自发荧光的影响，从而限制了生物传感/成像的灵敏度。人们期望进一步开发这些纳米晶体，以获得能够克服样品自发荧光的发光特性。另一方面，利用长寿命发光探针的时间分辨发光测量是一种有效的技术，可以在记录探针的时间分辨发光以进行信号测量时，消除样品的短寿命自发荧光，该测量是在光源脉冲激发之后进行的。尽管时间分辨测量非常灵敏，但许多当前长寿命发光探针的光学限制导致时间分辨测量通常在配备笨重且昂贵仪器的实验室中进行。为了将高灵敏度的时间分辨测量应用于现场或即时检测（POC），开发具有高亮度、低能量（可见光）激发和长达毫秒级长寿命的探针至关重要。这些理想的光学特性可以显著简化时间分辨测量仪器的设计标准，并促进开发用于现场或POC检测的低成本、紧凑、灵敏的仪器。锰掺杂的纳米晶体最近发展迅速，并为解决胶体半导体纳米晶体和时间分辨发光测量所面临的挑战提供了一种策略。在这篇综述中，我们概述了锰掺杂二元和多元纳米晶体开发中的主要成就，重点介绍了它们的合成方法和发光机制。具体而言，我们展示了研究人员如何在逐步理解锰发射机制的基础上克服这些障碍，以实现上述所需的光学性质。之后，我们回顾了锰掺杂纳米晶体在时间分辨发光生物传感/成像中的代表性应用，并展示了锰掺杂纳米晶体在推进用于现场或POC检测的时间分辨发光生物传感/成像方面的潜力。
