Long-range surface plasmon (LR-SP) is optical wave propagating along thin metal film between 2 dielectics with similar refractive indices, where the evanescent field intensity and the penetration depth is larger as compared to well-known short-range (SR)-SP evanescent field. Hence, it is expected to increase the sensitivity in the long distance from the metal surface. Electrospun fibers have been used to sensor applications because of their large surface area which is capable to adsorb a large amount of analytes. In this Experiment, water-stable electrospun poly(acrylic acid) fiber was fabricated and used to enhance the LR-SP based sensor surface for the detection of human immunoglobulin G (IgG).