In recent years, biosensors are being used for various medical and pharmaceutical purposes. For the formation of biosensors, one of the most commonly used phenomena is Surface Plasmon Resonance. Usually, biosensors are fabricated from optical fibers. However, when optical fibers are replaced with Photonic crystal fibers, the sensing properties are enhanced in a great way. These sensors are designed in such a way that a thin nanofilm of plasmonic metals like Gold, Silver, copper, aluminium, and plasmonic metal alloy gold-tin surround a surface containing air holes that are filled by a suitable analyte. This paper is aimed at designing an internal type PCF sensor with the analyte and multiple micrometer-sized holes in the middle. The different plasmonic materials are taken one by one and their properties are analyzed. The amplitude and wavelength sensitivities for each plasmonic material are calculated. The wavelength sensitivities for Silver, Gold, Aluminium, and copper are 1799nmRIU−1, 1830.76nmRIU−1, 1732nmRIU−1 and 1652 nm/RIU respectively. For the Gold-Tin alloy, the calculated value of the Sensitivity in the wavelength measurement is 1532.2nmRIU−1. The properties of these different sensors are then compared with each other. With the same set of chosen parameters, the best results are observed for Gold but the thickness of the gold film cannot be reduced below a few nanometers. Thus, in terms of stability and a wide range of parameters, silver has been observed to be the most suitable.