Carbon-Based Polymer Dots Sensor Array For Cells And Chiral Amino Acids Discrimination

Cell recognition with high sensitivity is of great value in biomedical field.Rapid detection of cell phenotypic is critical for the accurate prognosis of cancer and the design of subsequent drug therapy strategies.In the course of cancer treatment,it is necessary to distinguish normal cells from cancer cells,and then genetic or phenotypic analysis is performed to determine whether the diseased cells develop into a slow-growing benign tumor or a highly invasive malignant tumor.The determination of cell type is important for determining the optimal treatment time and schedule.Since most biomarkers have too high or too low expression levels in diseased cells,the traditional diagnostic methods of cancer are based on the detection of biomarkers such as genes,proteins or other specific molecules.Based on current understanding of biomarkers,methods such as mass spectrometry,electrophoresis,and antibody arrays have been employed as useful tools for cancer diagnosis.These diagnostic methods relying on individual biomarkers have some limitations such as low specificity,complex operation,expensive equipments,and time consuming.Moreover,the lack of unique markers or combinations of markers is often a major challenge for early diagnosis of cancer.Therefore,developing a method with high sensitivity,fast detection speed and low cost will enhance our ability to detect and recognize cancer.In recent years,the emergence of sensor array with cross-reactive receptors has provided an ideal platform for cell type discrimination.In this paper,a simple and efficient fluorescence array sensing platform was designed for the detection and discrimination of a variety of cancer cells.The first chapter of this thesis introduces the development history,applications,research status and future development trend of sensor array.It also briefly introduces the preparation method,composition structure and practical application of carbon dots.In the second chapter,three types of fluorescent carbon-based polymer dots(CPDs)were synthesized by room temperature oxidation polymerization with m-phenylenediamine,o-phenylenediamine,p-phenylenediamine,nitric acid and hydrogen peroxide as precursors.These CPDs can be abbreviated as m-CPDs,o-CPDs and p-CPDs.Fluorescence spectra and UV/vis spectra indicate that m-CPDs have a large absorption peak at 380 nm and a maximum emission wavelength at 463 nm,and strong blue fluorescence emission under ultraviolet light;o-CPDs have a large absorption peak at 370 nm and a maximum emission wavelength at 550 nm,and strong yellow fluorescence emission under ultraviolet light;p-CPDs have a large absorption peak at 470 nm and a maximum emission wavelength at 533 nm,and strong green fluorescenceemisson under ultraviolet light.All the CPDs exhibit excitation-independent photoluminescence(PL)behaviors and have different hydrophilicity in the buffer solution.What’s more,the surfaces of all the three CPDs have different contents of positive charge.Transmission electron microscope(TEM)results show that the three CPDs have good dispersibility and uniform size distribution.X-ray photoelectron spectroscopy(XPS)and Fourier transform infrared spectroscopy(FT-IR)demonstrate that these CPDs have similar chemical composition structures.In the third chapter of this thesis,a new fluorescent array sensing platform was explored based on CPDs.This sensing platform has the ability to recognize six types of cells.These CPDs are capable of interacting with the cell surface due to the different charges and hydrophilicity,resulting in a change in fluorescence intensity.The sensor array can not only recognize six types of cells at the same concentration(5000 cells/mL,2000 cells/mL,and 1000 cells/mL),two kinds of cells mixed in different ratios and a mixture of cells at the same ratio,but also determine response signal to cells within the range of 200-5000 cells/mL.The sensor array can be used for the detection of six kinds of cells in human serum and urine samples and for the discrimination of unknown cell samples.Finally,the sensor can also be used to identify six chiral amino acids and accurately distinguish cells from the peripheral blood of tumor-free and tumor-bearing mice.These results provide a good basis for the application of the platform in disease screening.