Implementación y prueba de una pinza óptica para captura y manipulación de micropartículas

Abstract

The motivation for developing this project was to design and implement, for the first time in Ecuador, a competitively priced optical tweezers system in relation to other highly complex optical systems that currently exist.

The assembled optical tweezers system consists of two sections: laser expansion system and focus and observation system. This design basically used a 658nm wavelength laser to trap microscopic objects and minimize the chances of damaging biological samples. Similarly, a camera with a CMOS sensor was used to record the capture and manipulation of microparticles on video.

The capture and manipulation of polystyrene microparticles was successfully demonstrated and the functionality of the system was characterized by estimating the stiffness with which the clamp catches and moves particles. For the calculation of this physical parameter, two passive calibration techniques were used for optical tweezers, the mean square displacement analysis (MSD) and the autocorrelation function analysis (ACF). Stiffnesses of 105,708 and 85,918 fN / nm were obtained for particles in water and in saline, respectively. The difference can be attributed to different viscosities of the solutions used.