Application of a Plasmonic Biosensor for Detection of Human-Liver Tissues

A recently published plasmonic biosensor based on birefringent solid-core microstructured optical fiber is applied for detection of five types of human-liver tissues (normal N, metastatic MET, non-cancerous metastatic (NMET), hepatocellular carcinoma (HCC), and non-cancerous hepatocellular carcinoma (NHCC)). The birefringent behavior is obtained by removing five central air holes of a two-ring hexagonal lattice of holes in a gold covered silica fiber with the liver layer surrounding the fiber. The loss spectra show two resonant peaks corresponding to the phase matching points. To distinguish between normal and malignant liver tissues, we compare the relevant parameter for the type I and II core modes. Thus, for a decrease of the real part of the refractive index from 1.373431 (human-liver N) to 1.354602 (human-liver MET), the resonance spectral width δλ0.5 is increased from 44.3 to 54.2 nm for the core mode II. In addition, the amplitude sensitivity SA is decreased from 158.6 to 88.4 RIU−1 for the same core mode. The advantages of another recently proposed plasmonic sensor based on a Bragg fiber are the larger values of the transmission loss, maximum value of the amplitude sensitivity, figure of merit, power fraction in a normal liver layer, and power fraction in the gold layer as compared with that for a microstructured fiber when applied for detection of a normal liver tissue. Another advantage of the Bragg fiber is related to the smaller value of the difference between maximal amplitude sensitivity and resonant wavelengths.