Study On The Design And Applications Of Novel DNA Molecular-based Fluorescent Probes

Nucleic acids play an essential role in living organisms because they store and transmit genetic information, and use that information to guide the synthesis of proteins. Apart from its basic function as a genetic code carrier, the use of DNA in various biosensor applications has been actively explored in the past. Making use of DNA’s ability to bind to a specific ligand, Oligonucleotide probes which are single-stranded nucleic acid fragments can be tailored to have high specificity and affinity for different targets. DNA also has a predictable base pairing, high chemical stability and convenience for synthesis and modification. Here we developed a series of functional DNA molecular probes and applied them to bio-analysis.1. A versatile molecular beacon (MB)-like probe was developed for multiplexed detection based on fluorescence polarization by target-induced allosteric effect and for resettable logic gate operation utilizing Ag+, Hg2+and cysteine as activators.2. The development of three novel DNA molecular probes based on Hoechst dyes. First, we have developed a molecular beacon (MB)-like DNA hairpin biosensing platform using Hoechst dye as a signal indicator, and demonstrate its feasibility in the application of fluorescent detection of Hg2+based on the Hg2+-thymine chemistry and furthermore for biothiol monitoring. Secondly, a novel graphene oxide-based fluorescent switch was developed to visually follow bioassay employing "molecular beacon"-hosted Hoechst dyes as signal indicators in a label-free format and for logic operation. Finally, we have successfully demonstrated that aptamer directing fluorescence of Hoechst dyes can be used as a label free signal indicator for inexpensive, simple, rapid, and selective detection of ATP.3. A novel strategy was proposed to highly sensitize the luminescence of terbium(III)(Tb3+) using a designed guanine/thymine-rich DNA (5’-[G3T]5-3’) as an antenna ligand, in which [G3T]5improved the luminescence of Tb3+by3orders of magnitude due to energy transfer from nucleic acids to Tb3+(i.e., antenna effect). Furthermore, label-free probes for the luminescent detection of biothiols, AgT, and sequence-specific DNA in an inexpensive, simple, and mix-and-read formatare presented based on the [G3T]5-sensitized luminescence of Tb3+...