Biomedical Detection Systems Based On Organic Synthesis And Nucleic Acid Chemistry

Sequence-specific DNA detection is now becoming the key diagnostic tool in modern biomedical tests. Highly sensitive and selective biological detection systems have been developed for molecular diagnostics, environmental monitoring, and disease prevention, etc. These systems use biological, organic and nanomaterials, which translates sequence information facilely into a variety of read-out formats. Despite great progress, however, to our knowledge, sentivity of a single molecular detection level yet field portable, easy to operate DNA detection methods still awaits to be discovered.We have developed a surface condensation of water strategy for the on-chip detection of DNA. This strategy relies on a target-driven alteration of surface wettability, and consequently, a transition of morphological state of and light propagation mode in the surface-condensed water, for the signaling of target. High sensitivity, high selectivity, and multiplexed analysis capability have been achieved in a label-free, direct spot array fabrication/visualization/imaging format, thus offering significant assay advantages over conventional diagnostic systems. Given recent advances in the tailored control of morphological state of surface-condensed water, the underlying principle described herein is likely extendable to the detection of other types of biological targets. We have developed a method for the synthesis of artificial nucleotide and proved its incorporation into DNA strand by various DNA polymerases. Utilizing the enzyme’s relatively tolerance for modification at the5-position of deoxyuridine triphosphate. We designed a uridine analogue containing2-Bromoisobutyryl functionalities. Starting from commercially available (+)-5-Iodo-2’-deoxyuridine, through a five step synthetic procedure, the target compound was successfully synthesized and charactered by1H-NMR,13C-NMR,31P-NMR, Elemental analysis, ESI-MS and HRMS. Further the recognization of the compound by four DNA polymerases was verified by three specially designed primer extension reactions. These designed reactions avoided the use of common autoradiography techniques.We have also developed other DNA detection related techniques. The utilization of the above synthesized compound was used in rolling circle amplification-ATRP related DNA detection systems. We also reported a method for one temperature synthesis of doped and alloyed Zn-Cd-Se nanocrystals. We have developed a one temperature ligase chain reaction method and by coupling with rolling circle amplification, the method was able to detect DNA at very low concentrations (600DNA molecules in1milliliter).