Design Of Biosensors Based On Functional Nanomaterials And Its Applications In Biomedical Study

With the growing number of cancer cases being diagnosed worldwide and theincreased number of fatalities due to late disease detection, biosensors can play animportant role in the early diagnosis of cancer.It has become more and moreimportant for highly sensitive and quantitative detection of biomolecules associatedwith human diseases. For example, the increase concentration of some proteins inblood may indicate cancer disease; the decrease or increase of microRNAconcentration may lead to many diseases. Recently, the application of nanomaterialsto detect disease biomarkers is giving rise to ultrasensitive assays, with scientistsexploiting the many advantageous physical and chemical properties ofnanomaterials. The emergence of nanotechnology is opening new horizons forbiosensor, with recent years witnessing the development and advantages of avariety of nanomaterial-based biosensors.These biosensors based nanoparticles,graphene oxide, carbon nanotubes and DNA nanostructures have already made amajor impact on clinical diagnostics, environment monitoring and food safety.Here, by combining DNA nanotechnology and functionalized nanomaterials, wedesigned several biosensor based on DNA Origami, graphene oxide, AuNPs andAgNPs SERS probes for highly sensitive and multiplexing detection of variousbiomolecules.1． Design of logic gates based on DNA Origami for microRNA diagnostics.We designed logic gates based on DNA Origami nanostructures formicroRNA diagnostics. The logic gates are composed of three modules:input module, computation module and output module. The inputmodule use microRNAs as the inputs of logic gates. The computationmodule analyzes the input signal and transduces the results to the output module. The output module will display the results of the logic gates. Weuse atomic force microscope to observe the computation results andmicroRNA diagnostics visually.2． Highly sensitive and multiplex detection of virus DNAs using Au-Ag SERSprobes.We prepared Au-Ag SERS probes with interior nanogaps for highlysensitive and multiplex detection of virus DNAs. Fluorescence dyes andsmall organic molecules with thiol could be used raman tags for the SERSprobes, which could be applied in multiplex detection and imaging.3． Graphene-based nanoprobes and a prototype optical biosensing platform.We have demonstrated that GO can be used for the preparation ofenzyme conjugates with high active-enzyme loadings per unit weight ofthe material. High-efficiency loading of enzymes onto the GO surface wasconfirmed by the characterization using standard kinetic assays and CDspectroscopy, demonstrating that the enzymes retained their nativeactivity and3D structure after adsorbing onto GO. Furthermore, we havedemonstrated the fabrication of GO-based probes and their use for ahighly sensitive detection of AFP.