Font Size: a A A

Optical Biochemical Sensing Detection Study Based On Graphene Oxide

Posted on:2018-12-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:Q ZhangFull Text:PDF
GTID:1318330515489107Subject:Biomedical engineering
Abstract/Summary:PDF Full Text Request
Because of its excellent characteristics such as heterogeneous chemical and electrical structure,abundant biomolecule binding sites,good water solubility and adjustable photoelectric properties,graphene oxide(GO)shows great potentials in the field of optical biosensing detection,and has been widely used for environmental monitoring,health care and food regulation.However,its current optical biosensing applications are mainly based on its characteristics such as photoluminescence and fluorescence quenching.Although optical sensing technologies such as fluorescence have advantages of high sensitivity and low detection limit,it also inevitably suffers from high detection equipment requirements,complex operation,additional label demands,and so on.These can increase the construction difficulties of graphene oxide-based optical biosensing systems,and then limit their practical application range.Therefore,it is of great importance for the practical application value enhancement of graphene oxide to raise a simple,fast,label-free and quantifiable optical detection technology,and to design highly sensitive biochemical sensors based on graphene oxide according to the technology.In this thesis,biosensing platforms such as GO-based biosensor,GO-based biomimetic sensor,and GO-based nano-compound sensors were designed and constructed through different modification approaches.Based on the optical characteristics of these sensors,ultraviolet-visible(UV-vis)absorption spectroscopy,which was simple for operation,fast for responding,low-cost,and easy to portability,was combined with these sensors to build a series of GO-based label-free optical biochemical sensing systems.And then,these systems were employed in applications such as odor molecule detection,sweet substance detection,and biomolecular detection.These studies verified the capability and reacting mechanisms of graphene oxide in construction of highly sensitive biochemical sensors,and the potential of UV-vis absorption spectroscopy combined with GO-based biochemical sensors in construction of label-free optical sensing platforms.The potential application values of graphene oxide in optical biochemical sensing fields were also studied.The main contents and innovations of this thesis are given as following:1.Designed and constructed a GO-based biosensing system with UV spectrum detection,and verified its application in odor molecule detection.In this thesis,peptides specifically sensitive to 2,4,6-trinitrotoluene(TNT)were synthesized and covalently crosslinked with graphene oxide to construct a GO-based biosensor.The biosensor was then combined with UV absorption spectroscopy and can detect TNT with dose-dependence and specificity.This study verified the capability of graphene oxide in construction of highly sensitive biosensors and signal transmission from biochemical signals to optical responses as a transducer,the ability of UV absorption spectroscopy to build optical biosensing systems combined with GO-based biosensors,and the application potential of the system in odor molecular monitoring.2.Designed and constructed a GO-based biomimetic sensing system with UV-vis spectrum detection,and verified its application in sweet substance detection.In this thesis,an UV-vis spectrum biomimetic sensing system was designed with combination of graphene oxide,hemin extracted from the hemoglobin activity center,and phenylboronic acid with similar sensory mechanism of biological taste receptors.Covalent and non-covalent combinations of these compounds were carried out to build a synthetic sugar transporter protein.The biomimetic sensor combined with UV-vis absorption spectroscopy can achieve the detection of saccharides and distinction between different kinds of saccharides.This study verified the capability of graphene oxide in construction of biomimetic sensors,the ability of UV-vis absorption spectroscopy to build optical biomimetic sensing systems combined with these sensors,and the application potential of the system in biomimetic sweet substance detection.3.Designed and constructed a GO-based nano-compound sensing system with visible spectrum detection,and studied its applications in detection of biomolecules and interactions between biomolecules.In this thesis,a nano-sensor based on composites of graphene oxide and gold nanoparticles was prepared through one-step synthetic method.Then the sensor was combined with visible absorption spectroscopy to build GO-based optical compound sensing system.And its applications in detection of biomolecules such as amino acids,peptides,and proteins were explored.Subsequently,peptides with thrombin-specific binding sites were further designed and synthesized in this thesis to construct a biosensor based on these composites and the peptides.An optical biosensing system was built by combination of visible absorption spectroscopy with the biosensor,which could realize thrombin detection with high sensitivity and high specificity.All these verified the capability of graphene oxide in construction of nano-compound biochemical sensors,the ability of visible absorption spectroscopy to build optical nano-compound sensing systems combined with these sensors,and the application potential of the system in detection of biomolecules and even biomolecular interactions.
Keywords/Search Tags:Graphene oxide, Biochemical sensor, Odor molecule detection, Sweet substance detection, Biomolecule detection
PDF Full Text Request
Related items