Neuron guidance and nano-neurosurgery using optical tools
- Autores: Manoj Vathalloor Mathew
- Directores de la Tesis: Pablo Loza Álvarez (dir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2009
- Idioma: inglés
- Tribunal Calificador de la Tesis: Dimitri Petrov (presid.), Juan Pérez Torres (secret.), Silvia Soria Huguet (voc.), Jesús Mariano Ureña Bares (voc.)
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
IIn recent years light has emerged as a very powerful tool in the biomedical field for investigation, diagnosis as well as therapies. The field 0 r,euroscience and medical neurology has also benefited immensely form use of these photonic tools. Axon guidance for example has been achieved b he use of CW light in contact with growth cones by exploiting light's ability to impart forces. Following this line of research our investigation revealed the potential of a pulsed laser light placed at a distance 10 induce a signaling effect and henc I?ttraclion in axons of cortical neurons in-vitro. Laser light was focused through a microscope objective to a point placed at a distance of about t5~rr rom the grO'N1h cone. The experiments were performed using continuous wave (CW), chopped CW (20Hz) and modelocked (FS) laser beam 80MHz) with 3mW of average power at the sample plane. In addition, a sham situation (no light beam) was used as a control. We found that CW hgh ~oes not produce any significant influence on Ihe axon grO'N1h. In contrast, when using pulsed light (chopped CW light or FS pulses), the beam wa ~ble 10 modify the trajectory of the axons, attracting approximately 45% of the observed cases to the beam spot. These results show that pulsed NIP aser light is capable of modulating the gro'N1h ofaxons in living cultured neurons. In the long term, this optically-based method has the potential to ope ~P new a\lemalives to guide axons and in the search for therapies fo~. neural degenerative disorders and Injuries. In order 10 exploit similar optically induced effects In-vivo a new oplical tool the multimodal optiCRI workstation was developed. The bASic motivatio ~ehind building this system was the development of a tool that could induce optical stimulation and at the same lime image the results of stimulatio Ive, using a multitude of imaging modalities. The workslation extends a commercially available confocal microscope (Nikon Confocal Ct-Si) to include ronlinear/multiphoton microscopy and optical manipulation/stimulation lools such as nanosurgery. The setup allows both subsystems (confocal anc ~?nlinear) to work independently and simultaneously. The workstation enables, for instance, confocal fluorescence microsopy. Laser Scanning Brigh Field (lSBF) imaging and Second Harmonic Generation (SHG) imaging to be performed althe same time. The nonlinear microscopy capabilities are ~dded around the commercial conlocal microscope by exploiting all the flexibility offered by this microscope and without need for any mechanical 0 lectronic modification 01 the confocal microscope systems. he multimodal optical workstalion was used for performing Nano-neurosurgery and observing the dynamics associated with the procedure b rnultimodal imaging of the procedure live, using a multitude 01 imaging modalities. A number of effects that happen along with the process 0 ranosurgery, like spilling of axoplasm, laser induced muscular contraction etc: were observed. A through assessment 01 collateral damage coula Iso be performed. The ability of the mullimodal system 10 assess collateral damage is much superior 10 the currently established ways 01 detecting ollateral damage after Nano-neurosurgey. In addition SHG microscopy was introduced as a novel technique 10 delect collateral damage to the muscle urrounding the neurite targeted for Nano-neurosurgery.
