광 산란 패턴의 발산 각도 분포를 이용한 비표지 박테리아 분별 기법에 관한 연구

Abstract

In this paper, we propose a scheme for label-free bacteria discrimination by utilizing the divergence angle of the scattering patterns of bacteria colonies. Three kinds of bacteria, such as Escherichia coli (E. coli), Salmonella typhimurium (S. typhimurium), and Listeria monocytogenes (L. monocytogenes), were compared in view of the divergence angle of their colony scattering patterns by using the proposed scheme. The diameter of the cultured bacteria colonies used for comparison ranged from 0.8 to 2.2 ㎜ for all the three specimens. First, to obtain their scattering patterns, each colony was illuminated by a low power green laser at 532nm. Then, the sizes of the scattering patterns were measured from the acquired colony scattering patterns. The divergence angles of the scattering patterns could be calculated by using the measured colony diameters and scattering pattern sizes. The experiment results show that there exists a unique range of the divergence angle according to the specimen. By analyzing and comparing the acquisition frequency of the divergence angle, this divergence angle range of the individual specimen was determined to be 4.23°∼8.12° for E. coli, 7.32°∼11.63° for S. typhimurium, and 10.36°∼16.37° for L. monoc ytogenes. From these evaluated divergence angle ranges, the three specimens can be simply identified through the measurement of the colony diameter and the scattering pattern size. This label-free discrimin ation scheme is expected to be beneficially utilized for simple verification of a conventional bacteria discri mination method.