30 March 2005 Nonlinear microspectroscopy in an optical tweezers system: application to cells marked with quantum dots
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In this work we used our set up consisting of an optical tweezers plus non-linear micro-spectroscopy system to perform scanning microscopy and observe spectra using two photon excited (TPE) luminescence of captured single cells conjugated with quantum dots of CdS and CdTe. The CdS nanocrystals are obtained by our group via colloidal synthesis in aqueous medium with final pH = 7 using sodium polyphosphate as the stabilizing agent. In a second step the surface of CdS particles is functionalized with linking agents such as Glutaraldehyde. The CdTe quantum dots are functionalized in the its proper synthesis using mercaptoacetic acid (AMA). We used a femtosecond Ti:sapphire laser to excite the hyper Rayleigh or TPE luminescence in particles trapped with an Nd:YAG cw laser and a 30 cm monochromator equipped with a cooled back illuminated CCD to select the spectral region for imaging. With this system we obtained hyper Rayleigh and TPE luminescence images of macrophages and other samples. The results obtained show the potential presented by this system and fluorescent labels to perform spectroscopy in a living trapped microorganism in any neighbourhood and dynamically observe the chemical reactions changes in real time.
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Adriana Fontes, Adriana Fontes, Andre A. de Thomaz, Andre A. de Thomaz, Wendel L. Moreira, Wendel L. Moreira, Antonio A. R. Neves, Antonio A. R. Neves, Luiz Carlos Barbosa, Luiz Carlos Barbosa, Patricia Maria Albbuquerque de Farias, Patricia Maria Albbuquerque de Farias, Beate Saegesser Santos, Beate Saegesser Santos, Carlos Lenz Cesar, Carlos Lenz Cesar, } "Nonlinear microspectroscopy in an optical tweezers system: application to cells marked with quantum dots", Proc. SPIE 5700, Multiphoton Microscopy in the Biomedical Sciences V, (30 March 2005); doi: 10.1117/12.586433; https://doi.org/10.1117/12.586433

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