title: Stable DNA Nanomachine Based on Duplex-Triplex Transition for Ratiometric Imaging Instantaneous pH Changes in Living Cells.
abstract: DNA nanomachines are becoming useful tools for molecular recognition, imaging, and diagnostics and have drawn gradual attention. Unfortunately, the present application of most DNA nanomachines is limited in vitro, so expanding their application in organism has become a primary focus. Hence, a novel DNA nanomachine named t-switch, based on the DNA duplex-triplex transition, is developed for monitoring the intracellular pH gradient. Our strategy is based on the DNA triplex structure containing C(+)-G-C triplets and pH-dependent Förster resonance energy transfer (FRET). Our results indicate that the t-switch is an efficient reporter of pH from pH 5.3 to 6.0 with a fast response of a few seconds. Also the uptake of the t-switch is speedy. In order to protect the t-switch from enzymatic degradation, PEI is used for modification of our DNA nanomachine. At the same time, the dynamic range could be extended to pH 4.6-7.8. The successful application of this pH-depended DNA nanomachine and motoring spatiotemporal pH changes associated with endocytosis is strong evidence of the possibility of self-assembly DNA nanomachine for imaging, targeted therapies, and controllable drug delivery.
authors.affiliation: †Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry, Beijing Institute of Technology, 5 Zhongguancun Road, Beijing 100081, P. R. China.
authors.forename: Mengqi
authors.initials: M
authors.lastname: Yang
authors.affiliation: †Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry, Beijing Institute of Technology, 5 Zhongguancun Road, Beijing 100081, P. R. China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Zhang
authors.affiliation: ⊥College of Engineering, Wayne State University, Detroit, Michigan 48202, United States.
authors.forename: Haipeng
authors.initials: H
authors.lastname: Liu
authors.affiliation: §College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, P. R. China.
authors.forename: Huaizhi
authors.initials: H
authors.lastname: Kang
authors.affiliation: §College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, P. R. China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: †Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry, Beijing Institute of Technology, 5 Zhongguancun Road, Beijing 100081, P. R. China.
authors.forename: Wen
authors.initials: W
authors.lastname: Yang
authors.affiliation: ‡Center for Research at Bio/nano Interface, Department of Chemistry, Department of Physiology and Functional Genomics, Shands Cancer Center, UF Genetics Institute, and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611-7200, United States.|∥Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics, Hunan University, Changsha 410082, P. R. China.
authors.forename: Weihong
authors.initials: W
authors.lastname: Tan
mesh_terms: D002470:Cell Survival; D004247:DNA / Q000737:chemistry*; D031541:Fluorescence Resonance Energy Transfer; D056945:Hep G2 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D036103:Nanotechnology; D009690:Nucleic Acid Conformation
chemical_list: D004247:DNA