Nano-biosensors Assembled By Graphene Oxide And DNA Quantum Dots And The Application In Logic Detection

The development of nanomaterials has promoted the development of nanotechnology,and their interdependence and mutual penetration with other disciplines have led to the development of various fields.Quantum dots(QDs)are widely concerned due to their unique optical and electrical properties,and their superior fluorescent properties make them a potential alternative to traditional organic dyes for construction of detective biosensors,QDs were widely used in the biosensing,biological imaging,biological logic gate and biomedical fields.Graphene has been widely concerned since its discovery.Graphene oxide(GO)is a kind of derivative of graphene,which has good water solubility and biocompatibility.Because of its large specific surface area and large conjugated system,GO has good fluorescence quenching performance.Therefore,GO shows a good application prospects in the nano-biological detection,sensing and construction of logical computing structures.DNA is a biological macromolecule,and related with human genetic information and certain disease.Also,it has caused research boom on its structure and potencial application value.DNA unique double helix structure make single-stranded DNA identify the complementary DNA specifically,which can be served as molecular detection,sensing,molecular computing and other fields.DNA can be constructed logic circuits to detect the single molecule or multivariate DNA molecules.Meanwhile,the development of DNA logic gates promotes the development of molecular computing.In this paper,a nano-biosensor with GO and DNA-quantum dots was assembled for the detection of double DNA molecules,and the reversible design and recycling of the sensor were realized,which provided a new method for the detection of binary pathogenic factors.The specific chapters are as follows: Chapter 2,we prepared water-soluble DNA-quantum dots(P1),and explored the fluorescence properties of them and their hybridization properties with complementary DNA.The quantum yield of the P1 is high.They are easy to hybridize with the complementary DNA strand.In addition,after packaging one or two layers of CdS shells on the surface,The DNA-quantum dots showed strong anti-bleaching ability,which provided a good fluorescent material for the construction of the sensor.Chapter 3,Synthesis of single-layer sheet GO by chemical oxidation-ultrasound assisted.The GO has a singlelayer lamellar structure.It has high fluorescence quenching efficiency for DNA-quantum dots which is the basis for the construction of biological logic sensor.Chapter 4,the assembly of the two kinds of nano-materials can constitute a logic detection sensor.The DNAtemplated CdTe quantum dots(P1)were assembled with GO by ?-? stacking.Based on the FRET principle and the difference between the adsorption of single and double strand DNA,the two target molecules were identified,and a simple Binary Detection Logic Gate-"OR" Logic Gate was constructed achieving the detection of double DNA molecules.On this basis,we improved the DNA sequence,and realized the reversible design of the sensor,reaching the purpose and effect of multiple cycles,which had potential application value in the field of biomolecule detection and disease diagnosis.