title: A duplex-triplex nucleic acid nanomachine that probes pH changes inside living cells during apoptosis.
abstract: A duplex-triplex switchable DNA nanomachine was fabricated and has been applied for the demonstration of intracellular acidification and apoptosis of Ramos cells, with graphene oxide (GO) not only as transporter but also as fluorescence quencher. The machine constructed with triplex-forming oligonucleotide exhibited duplex-triplex transition at different pH conditions. By virtue of the remarkable difference in affinity of GO with single-stranded DNA and triplex DNA, and the super fluorescence quenching efficiency of GO, the nanomachine functions as a pH sensor based on fluorescence resonance energy transfer. Moreover, taking advantage of the excellent transporter property of GO, the duplex-triplex/GO nanomachine was used to sense pH changes inside Ramos cells during apoptosis. Fluorescence images showed different results between living and apoptotic cells, illustrating the potential of DNA scaffolds responsive to more complex pH triggers in living systems.
authors.affiliation: State Key Laboratory Base of Eco-chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China. xuemei_li@yeah.net
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Song
authors.forename: Tao
authors.initials: T
authors.lastname: Cheng
authors.forename: Pei-Yu
authors.initials: PY
authors.lastname: Fu
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002478:Cells, Cultured; D004247:DNA / Q000737:chemistry*; D004867:Equipment Design; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D006108:Graphite; D006801:Humans; D006863:Hydrogen-Ion Concentration; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods*; D009690:Nucleic Acid Conformation; D014750:Vincristine / Q000494:pharmacology
chemical_list: C051802:triplex DNA; D014750:Vincristine; D006108:Graphite; D004247:DNA