Figure 1.

Schematic representation of working of AuNP- oligo probe assay. a) In the presence of Escherichia coli genomic DNA, AuNP- oligo probes are stabilized and prevented from aggregation upon acid addition. Red color of the solution indicates presence of target DNA and hence POSITIVE. b) In the presence of non Escherichia coli genomic DNA, AuNP- oligo probes loses its stability and tend to aggregate. Purple color of the solution indicates absence of target DNA and hence NEGATIVE.