Chemotaxis study using optical tweezers to observe the strength and directionality of forces of Leishmania amazonensis

Liliana de Ysasa Pozzo; Adriana Fontes; André A. de Thomaz; Luiz Carlos Barbosa; Diana Copi Ayres; Selma Giorgio; Carlos Lenz Cesar

doi:10.1117/12.680999

11 September 2006 Chemotaxis study using optical tweezers to observe the strength and directionality of forces of Leishmania amazonensis

Liliana de Ysasa Pozzo, Adriana Fontes, André A. de Thomaz, Luiz Carlos Barbosa, Diana Copi Ayres, Selma Giorgio, Carlos Lenz Cesar

Author Affiliations +

Proceedings Volume 6326, Optical Trapping and Optical Micromanipulation III; 63262A (2006) https://doi.org/10.1117/12.680999
Event: SPIE Optics + Photonics, 2006, San Diego, California, United States

Abstract

The displacements of a dielectric microspheres trapped by an optical tweezers (OT) can be used as a force transducer for mechanical measurements in life sciences. This system can measure forces on the 50 femto Newtons to 200 pico Newtons range, of the same order of magnitude of a typical forces induced by flagellar motion. The process in which living microorganisms search for food and run away from poison chemicals is known is chemotaxy. Optical tweezers can be used to obtain a better understanding of chemotaxy by observing the force response of the microorganism when placed in a gradient of attractors and or repelling chemicals. This report shows such observations for the protozoa Leishmania amazomenzis, responsible for the leishmaniasis, a serious tropical disease. We used a quadrant detector to monitor the movement of the protozoa for different chemicals gradient. This way we have been able to observe both the force strength and its directionality. The characterization of the chemotaxis of these parasites can help to understand the infection mechanics and improve the diagnosis and the treatments employed for this disease.

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Liliana de Ysasa Pozzo, Adriana Fontes, André A. de Thomaz, Luiz Carlos Barbosa, Diana Copi Ayres, Selma Giorgio, and Carlos Lenz Cesar "Chemotaxis study using optical tweezers to observe the strength and directionality of forces of Leishmania amazonensis", Proc. SPIE 6326, Optical Trapping and Optical Micromanipulation III, 63262A (11 September 2006); https://doi.org/10.1117/12.680999

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