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Fabrication of multi-doped microstructures by two-photon absorption photopolymerization

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Adriano José Galvani Otuka
Total Authors: 1
Document type: Master's Dissertation
Press: São Carlos.
Institution: Universidade de São Paulo (USP). Instituto de Física de São Carlos (IFSC/BT)
Defense date:
Examining board members:
Cleber Renato Mendonça; Thiago Pedro Mayer Alegre; Valmor Roberto Mastelaro
Advisor: Cleber Renato Mendonça

Doped microstructures have attracted interest in optics, photonics and biology, because they allow the production of devices with specific proprieties. However, doping microstructures with more than one dopant is not much exploited in the literature. In this work we demonstrate the development of a method to fabricate multi-doped microstructures by two-photon absorption polymerization. For the microfabrication we used a femtosecond laser (Ti:sapphire laser, 780 nm, 100 fs) that is focused, by a microscope objective, in the volume of a polymeric resin containing a photoinitiator organic compound responsible to initiate the polymerization. The intensity of the femtosecond pulses is high enough to induced two-photon absorption, and consequently polymerization, only around the focal volume. As dopants we employed the fluorescent dyes Rhodamine and Fluorescein. In order to verify the microfabrication system, we have initially fabricated microstructures with only one dopant, which were characterized using optical and electron microscopies. Microstructures containing more than one dopant, in distinct regions, were produced by sequential fabrication of single doped structures. Such method allowed the fabrication of double doped structures, which presents good structural integrity and maintain the characteristic optical properties of the dyes. Finally, aiming at biological applications, we employed the developed method to fabricate micro-environments doped, in specific sites, with the antibiotics ciprofloxacin hydrochloride. Initial studies on the growth of the bacterium Escherichia coli, on such microstructures, were carried out to demonstrate the feasibility for such type of application. (AU)

FAPESP's process: 09/10897-2 - Fabrication of multi-doped microstructures by two-photon absorption photopolimerization.
Grantee:Adriano José Galvani Otuka
Support type: Scholarships in Brazil - Master