Molecular Labeling of DNA Amyloid Sensor with Plasma, and the Glycemic Factor, for Photonic Detection of Alzheimer's in Blood

Abstract

This investigation was carried out based on the integrative approach at the cellular, molecular and atomic level. Therefore, our aim was to develop two DNA sensors that detect Alzheimer's disease related β-amyloid protein in blood using synthetic and molecular biology. The DNA sensors were constructed in E. Coli or Saccharomyces cerevisiae using genetic sequences and they were tested in terms of fluorescence expression units (FSU) when mixed with human blood plasma using a fluorescence detector. This amyloid sensor was also confirmed using photonic Raman technology, and corroborated by analyzing the purified protein using SDS-PAGE gel electrophoresis, which product was confirmed by using different sizes of Macrosep Advance Centrifugal devices. The intensity of the detection was enhanced by labeling the fluorescence targeted molecules in samples which were conjugated with fluorescent dyes.Fluorescence results were comparable to clinical and MRI results. The DNA sensor was able to detect β-amyloid protein in different type of patients. Results were also correlated with the glycemic levels of the patients. Influence of metals on expression of amyloid protein was also demonstrated through ELISA and Western Blot assays. Due to the highly correlation between fluorescence intensity and levels of β-amyloid, these results were used to classify patients according to the severity of Alzheimer's (i.e. Group1: Alzheimer's Diagnosed; Group2: Pre-Alzheimer's; and Group3: Normal) in addition to clinical medical symptoms (e.g., memory loss, cognitive impairment such as mental disorientation and/or mental confusion) and MRI results. Statistical analysis showed that the groups were well categorized based on the three selected parameters. Group 1 showed the highest fluorescence total mean followed by Group 2, as compared to Group 3, which exhibited the lowest total mean. Gender seemed to be an associate factor at time of the disease onset.These results suggest the advantage of using this method for early detection of Alzheimer's disease as well as the importance of metals for triggering the expression of β-amyloid protein.