Application Of Fluorescent Carbon Dots For Point-of-care Testing Of Lysine And Glutathione

Carbon dots（CDs）are a new frontier field of fluorescent nanomaterials,which are easy and fast to synthesize in accordance with green chemistry principles.Amino acids are important indicators in the animal growth process and are closely related to animal metabolism.At present,there are many methods for conventional detection of amino acids,such as the amino acid analyzer method,High performance liquid chromatography,and ion chromatography-integrated pulse amperometric methods.Conventional instrumentation methods are defective in agricultural production due to high cost,inconvenience of mobility,and the need for dedicated personnel to operate them.New materials such as carbon dots have opened up new directions for the instant detection of livestock metabolites.Microfluidics shows great advantages in modern analytical techniques,such as rapid analysis,low reagent consumption and easy operation.In the detection applications of microfluidic systems,microsensors require only minute amounts of reagents,but require highly sensitive response methods.Integrating microfluidic chips with carbon dots highlights the advantages of both and enables the construction of micro-optical detection sensors.We therefore consider the development of portable devices based on microfluidics by assembling CDs with hydrogels into small detectors and immobilizing them in microfluidic devices.1.The fluorescent CDs were synthesized by using o-phenylenediamine and its derivatives with Zn Cl₂ under relatively mild conditions.The fluorescence intensity of CDs showed a good positive linear relationship.A well positive linear relationship was observed between the lysine and the fluorescence intensity of N-CDs at 1-300μmol/L.2.A microfluidic detection chip was fabricated.By injecting a gel-CDs mixture solution,which is UV-cured,a microgel structure with encapsulated CDs can be formed at the designated location of the chip.The designed chip has two parallel channels,one as the detection channel and the other as the reference channel.The sample was injected into the detection channel,and the lysine had a significant positive linear relationship with the relative fluorescence intensity between 25-300μmol/L.The constructed microfluidic chip can be used for the instant detection of porcine serum samples.3.A microfluidic chip-based imaging device was designed.It was designed by Solid Works software,printed and fabricated by a 3D printer,and matched with accessories such as filters,lenses,and light sources according to the optical properties of CDs microgels.The fluorescence intensity of CDs microgels in the microfluidic chip was photographed using a smartphone to establish a linear relationship between the relative fluorescence intensity and the concentration of the substance to be measured.CDs for detecting glutathione were synthesized to explore their optical characteristics.The device was successfully applied to the quantitative detection of lysine and glutathione in pig serum,both with well results.In this thesis,CDs were synthesized from common laboratory materials for the quantitative detection of lysine and glutathione;a microfluidic chip and imaging device were developed for immediate detection in animal husbandry,and lysine and glutathione were quantitatively detected in pig serum,which is a universal method and reflects the promising application of fluorescent CDs in animal science and animal medicine.