Patent ID: 7101671

Claim:
Method for detecting DNA hybridization on DNA chips using 4-Dimensional parameters which comprises the following steps: (1) placing a DNA chip containing probes in a temperature-controlled chamber; (2) incubating the DNA chip with single-stranded target oligos and a fluorescent dye in a reaction buffer, wherein the fluorescent dye inserts into double-stranded DNA molecules; (3) lowering the temperature in the temperature-controlled chamber to the annealing temperature (Th), wherein the single-stranded target oligos hybridize to the probes on the chip to form double-stranded DNA molecules and wherein the fluorescent dye inserts into the double-stranded DNA molecules thereby, labeling the double-stranded DNA molecules with the fluorescent dye; (4) increasing the temperature in the temperature-controlled chamber from Th to 100° C. at the speed of 0.001–1° C./sec, (5) scanning the chip at each ΔT° C. by a scanner to obtain a fluorescent intensity F, wherein when the temperature in the termparature-controlled chamber reaches the melting temperature Tm for a given probe, the double-stranded DNA molecule dissociates and the fluorescent dye diffuses into the buffer, resulting in a rapid loss of fluorescent intensity; wherein the scanning of fluorescent intensity of every probe on the chip records the turning point on a continuous melting curve or a derivative melting curve for each of the double-stranded DNA molecules, which provides the Tm of each of the double-stranded DNA molecules at the peak position on the curves; and (6) comparing the Tm for each probe from step (5) with the known optimum melting temperature for each of probe that hybridzes perfectly with a complementary target oligo (Tmp) to detect the presence of the perfectly complementary target oligo, wherein the target oligo is present when the Tm equals Tmp for a given probe.