Istituto di Fisica Applicata Nello Carrara, Consiglio Nazionale delle Ricerche, Sesto Fiorentino, Italy.
Anal Bioanal Chem. 2013 Jul;405(19):6181-96. doi: 10.1007/s00216-013-7086-8. Epub 2013 Jun 21.
Fluorescence imaging coupled with nanotechnology is making possible the development of powerful tools in the biological field for applications such as cellular imaging and intracellular messenger RNA monitoring and detection. The delivery of fluorescent probes into cells and tissues is currently receiving growing interest because such molecules, often coupled to nanodimensional materials, can conveniently allow the preparation of small tools to spy on cellular mechanisms with high specificity and sensitivity. The purpose of this review is to provide an exhaustive overview of current research in oligonucleotide optical switches for intracellular sensing with a focus on the engineering methods adopted for these oligonucleotides and the more recent and fascinating techniques for their internalization into living cells. Oligonucleotide optical switches can be defined as specifically designed short nucleic acid molecules capable of turning on or modifying their light emission on molecular interaction with well-defined molecular targets. Molecular beacons, aptamer beacons, hybrid molecular probes, and simpler linear oligonucleotide switches are the most promising optical nanosensors proposed in recent years. The intracellular targets which have been considered for sensing are a plethora of messenger-RNA-expressing cellular proteins and enzymes, or, directly, proteins or small molecules in the case of sensing through aptamer-based switches. Engineering methods, including modification of the oligonucleotide itself with locked nucleic acids, peptide nucleic acids, or L-DNA nucleotides, have been proposed to enhance the stability of nucleases and to prevent false-negative and high background optical signals. Conventional delivery techniques are treated here together with more innovative methods based on the coupling of the switches with nano-objects.
荧光成像与纳米技术相结合，使得在生物学领域开发强大的工具成为可能，例如细胞成像、细胞内信使 RNA 监测和检测。将荧光探针递送到细胞和组织中越来越受到关注，因为这些分子通常与纳米级材料结合，可以方便地制备小分子工具，以高特异性和灵敏度监测细胞机制。本文综述了用于细胞内传感的寡核苷酸光开关的最新研究进展，重点介绍了这些寡核苷酸所采用的工程方法以及将其内化到活细胞中的最新迷人技术。寡核苷酸光开关可以定义为经过精心设计的短核酸分子，能够在与明确的分子靶标相互作用时打开或修饰其光发射。分子信标、适体信标、杂交分子探针和更简单的线性寡核苷酸开关是近年来提出的最有前途的光学纳米传感器。已经考虑用于传感的细胞内靶标是大量表达信使 RNA 的细胞蛋白和酶，或者在基于适体的开关的情况下，直接是蛋白质或小分子。为了增强核酸酶的稳定性并防止假阴性和高背景光学信号，已经提出了包括用锁核酸、肽核酸或 L-DNA 核苷酸修饰寡核苷酸本身在内的工程方法。本文还介绍了常规的递释技术以及基于将开关与纳米物体耦合的更具创新性的方法。
