The main trend in optical biosensor is to develop fast, sensitive and low cost devices. This device used for detecting the changes of liquid properties such as refractive index, absorption or fluorescence. This is one approach to design sensors which are sensitive to layer modification with specific chemical or physical properties. They are capable of rapid and sensitive detection of the target in real time using a label-free scheme. This project describes sensing approach based on a functionalized microstructured optical fiber-Bragg grating for specific DNA target sequence detection. The inner surface of a microstructured fiber, where a Bragg grating was previously inscribed, has been functionalized by covalent linking of a peptide nucleic acid probe targeting a DNA sequence. In this case, DNA target was a sequence of genetically modified transgenic soybean. In order to achieve signal amplification, ON-functionalized titanium oxide nanoparticles were infiltrated and used in a sandwich-like assay. Experimental measurements and the analysis of spectra of the reflected signal obtained from measurements show a clear shift of the reflected Bragg grating at high order mode , λᴃ = 0.23nm and 0.17nmThe shift occur at the fundamental mode λᴃ = 0.03nm , and 0.07nm. This shift of the reflected wavelength of Bragg demonstrates the efficient capture, by the PNA, DNA, and the NPs. Finite element analysis of the Penta PCF was simulated using COMSOL Multiphysics 4.3. The simulation software result was ∆λᴃ = ± 0.243 nm, it was near compared to experimental results.