The study on assembling process of IFN-gamma DNA sensor by surface plasmonresonance

A practical and simple DNA sensor based on surface plasmon resonance (SPR) has been developed to determine the interferon gamma (IFN - gamma). This SP R instrument was designed on the basis of simultaneous multi - wavelength d etection. IFN - gamma oligonucletide DNA chemically labeled with biotin was used as the probe. Biotin - avidin system was used to immobilize the bio - DNA on the sensor surface. The assembling process and condition of the DNA sensor were examined in detail. The SPR sensor can be used to monitor the process of the immobility of the bio - DNA and DNA hybridization in real - time. The determination range of IFN - gamma oligonucleotide (24 bases) is 50 similar to 400 ng/mL. The determination range of polymerase chain reacti on (PCR) product of IFN - gamma (247 bases) is 5 similar to 40 ng/mL. The s tability, reversibility and specificity of the DNA sensor were also investi gated. It is found from the experiment that the sensor can be applied for l onger time (about 100 times). The relative standard deviation (RSD) for det ermination DNA and PCR product of DNA was 1.2% and 1.4%, respectively. The interference of noncomplementary DNA sequence with the determination of DNA was examined. It is found that noncomplementary 20 - mer and 21 - mer DNA (ICE - F and ICE - R) do not affect the determination of DNA.