Tapered Optical Fiber for Porcine DNA Detection Based on Evanescent Field Sensing Method

This paper proposes the development of tapered optical fiber for porcine DNA detection based on the evanescent field sensing method. DNA detection is most common method compared with protein detection due to complexity and denaturation of protein. Optical single mode fiber (SMF) of 125 μm diameter is tapered to produce 12 μm waist diameter and 15 mm length. Probe DNA is immobilized onto the bare tapered region and subsequently hybridized by its complementary DNA (cDNA). The experiment starts with dropping an optimum concentration probe (6 μM) and target DNA (4 μM) on the tapered region. The transmission spectra of the DNA-based optical fiber sensor are measured in the 1500 to 1600 nm wavelength range. It is discovered that the shift of the wavelength in the SMF sensor is linearly proportional with the increase in the cDNA concentrations from 1 x10<sup>-15</sup> to 1 x10<sup>-6</sup> M. The linear range of the sensor in the direction of DNA is measured as 1 x10<sup>-10</sup> to 1 x10<sup>-6</sup> M. This sensor has a sensitivity level of 0.224nm/log [cDNA]M with a detection limit (LOD) of 6.16875×,10<sup>−11</sup>. M. From the result obtained, porcine DNA is detected using tapered optical fiber without any surface modification involving chemical reagents is successfully proposed and developed in this project. The probe DNA immobilization and target DNA hybridization without any surface modification from the functionalized process, it will avoid time consuming and tedious process which involved several chemicals reagents. From the result obtained, the proposed tapered optical fiber is the potential for DNA hybridization detection.