Novel Molecular Spectroscopy Approaches And Drug Screening For Early Diagnosis Of Alzheimer’s Disease And Colorectal Cancer

Abstract:Alzheimer’s disease (AD) and cancer are two kinds of critical diseases which threaten the human health, ranking the fourth and the second in fatality rate respectively. AD is a kind of progressive and devastating neurodegenerative disease in the elderly. Although the pathogenesis of AD remains unclear, it is often believed that β-amyloid protein (Aβ) extracellular amyloid-(3peptide (A(3) plaques and intracellular neurofibrillary tangles are the main reasons for degeneration and death of neurons. It is shown that A(3could be a biomarker of AD. Therefore, it is very important to sensitively detect A(3for the early diagnosis of AD.Colorectal cancer (CRC) is one kind of high-incidence cancers. Developing novel assays of early diagnosis and screening new anti-tumor drugs are hot issues of common concern. Active ingredients from natural plants are the import sources of new drugs because of their small-side effects.This paper consists of the following three parts:Firstly, the fabrication of Fe3O4@Au composites was demonstrated as a novel resonance light scattering (RLS) probe for the sensitive detection of Alzheimer’s amyloid-β peptide (Aβ). The RLS intensity of Fe3O4@Au composites was significantly enhanced by interacting with Aβ. Under optimal conditions, good linear relationship, between the ratio of RLS intensity Ⅰ/Ⅰ0at463.0nm and the logarithmic value of Aβ concentration in the range of5.0×10-15-5.56×10-9mol·L-1, was found. The limit of detection (LOD) was1.2×10-15mol·L-1. The proposed method is simple, sensitive and cost-effective, and also complementary to other existing methods for protein analysis.Secondly, three-dimensional fluorescence spectra provide more comprehensive information than common fluorescence emission spectra, and are preferred to the analysis of complex system because of the advantages such as fingerprint, high amount of information, high sensitivity, high selectivity and so on. In this paper, three-dimensional fluorescence spectra of human serum samples including35CRC samples were recorded. Chemometrics for pattern recognition (three-way PLS) was used to discriminating analysis and discriminating model for CRC, and control group was established. This assay brings up a new approach to the early diagnosis of CRC.Finally, Dextran/Fe3O4composite magnetic nanoparticles have a lot of advantages, such as superparamagnetism, reproducibility and good biocompatibility and have been widely used in the fields of biology and medicine. In this study, one-step synthesis of dextran/Fe3O4composites was carried out by hydrothermal method under optimal conditions. The resultant composites exhibited good dispersion and stability. Then, bovine serum albumin (BSA) molecules were immbolized onto the surface of dextran/Fe3O4nanoparticles.The BSA coated dextran/Fe3O4nanoparticles were successfully applied to extract active ingredients from pentaphyllum. The study has potential potential applications in drug screening.