SERS Detection Of Neurotransmitters In Microfluidic Chip

Neurotransmitters are a series of molecules that transmit signals between cells and regulate physiological functions.Detection of neurotransmitters can help clinical diagnosis and treatment of related diseases,and promote the understanding of relevant neurological processes.In consideration of sensitive detection of neurotransmitters,new surface enhanced Raman scattering(SERS)-based methods are developed and combined with microfluidic chip to construct highly sensitive SERS detection chips,which is used for clinical neurotransmitter detection and secretion monitoring of neurotransmitters from neurons under the different drug treatments.The main research results include:A method of DNA-assisted synthesis of zipper-like nanodimer with nano-and subnano-scale controllable interparticle gap is proposed.This method utilizes the equilibrium state of DNA hybridization and electrostatic repulsion between nanoparticles to synthesize zipper-like nanodimers with an ultra-narrow uniform nanogap.Different from conventional DNA-based dimers,zipper-like nanodimers generate sub-nanometer interparticle gap by inversing the hybridization direction of DNA on nanoparticles.The interparticle gap width can be tuned from sub-nanometer to several nanometers by changing the DNA sequences or the surface charges of nanoparticles,thereby providing huge electromagnetic enhancement and excellent SERS reproducibility for accurate and sensitive SERS detection.A highly sensitive microfluidic-SERS chip for the detection of dopamine was constructed.In the chip,aptamer-based SERS probes are used to form zipper-like nanodimers in the microfluidic channel,which serve as the SERS detection unit.The specific binding of dopamine and its aptamer leads to the detachment of SERS probe,thereby causing the rapid decrease of SERS intensity,which is used for the detection of dopamine.Due to the extremely high sensitivity and accuracy of such a dopamine detection chip,rapid determination of dopamine level in clinical blood samples is achieved.Dynamic monitoring of dopamine secretion from living neurons is also achieved by integrating a three-dimensional cell culture unit into the same chip.A highly sensitive microfluidic-SERS chip for the detection of acetylcholine was constructed based on the newfound modulation effect of acetylcholine on the SERS signal of other Raman probe molecules.Wild and tunable detection range for acetylcholine is achieved by changing the type and the concentration of Raman probe molecules.By integrating the SERS detection method and 3D cell culture unit into single microfluidic chip,the monitoring of acetylcholine secretion from living neurons under different external stimuli or drug treatments is realized,which holds important application value in in-vitro drug screening and drug efficacy evaluation.