Amino acids not only play a vital role as protein-building constituents in living beings but also have a wide range of applications that include commercial industries such as food additives and flavor enhancers as well as medical sectors to resist numerous disease levels and to treat digestive abscesses, liver ailments, etc. Hence a precise and feasible detection of amino acids is a fervent desire for their appropriate applications. This paper presents an amino acid sensor employing a mono-circular hollow-core PCF. This PCF-based sensor has been designed maintaining high fabrication feasibility. Then the performance of this sensor has been numerically studied engaging finite element method while sensing five types of amino acids. Performance metric exhibits that this sensor has a very low effective material and confinement loss of about 0.003795 cm-1 and 3.065×10-15 cm-1 correspondingly at 2.7 THz for Tryptophan. Besides this sensor has offered approximately 97.12% relative sensitivity maintaining a higher numerical aperture for the same type of amino acid. This sensor has maintained admirable values for all the performance indices for all the five types of amino acids analyzed in this paper. Furthermore, the elementary design of this sensor has opened the door of viable fabrication with the aid of existing sol-gel technique or extrusion with 3D printing method.