ABSTRACT
Using the HRP-functionalized liposomes, the analyte (27) could be sensed without any attempt to optimize the process, with a sensitivity that corresponds to 1×10−13 M. The sensing process is very specific, and the interaction of the sensing interface with the normal gene, (27a), at a concentration that corresponds to 1.3×10−8 M, followed by a sequence of amplifications with the HRP-functionalized liposomes, and the biocatalyzed precipitation of (8) results in an increase in the electron transfer resistance of only 0.2 kΩ (Note that the same protocol for the analyte (27), 6.5×10−12 M, results in an increase in the electron transfer resistance of 2.7 kΩ.) Thus, the system is free from the binding of the noncomplementary normal gene, (27a), and from the nonspecific binding of the labeled liposomes. This might be attributed to the electrostatic repulsion of the liposomes by the negatively charged oligonucleotide sensing interface.
