There is a current void in efficient, cell-specific, retinal drug delivery systems, thus developing a safe, effective, selective drug delivery system would open novel therapeutic avenues. We previously demonstrated that femtosecond (fs) laser irradiation can selectively transfect DNA plasmids into cultured cells in the presence of functionalised gold nanoparticles (AuNPs) (1). Here, we sought out to selectively optoporate retinal cells in vivo with functionalized AuNPs and a 800nm fs laser. The cell-surface Kv1.1 voltage-gated channel was chosen to target retinal ganglion cells (RGCs) in the rat retina. The eyes of anesthetized rats were placed in the beam path of an optical system consisting of a fs laser and an ophthalmoscope for fundus visualization. Following Kv1.1-AuNP and FITC-dextran intravitreal injection and incubation, irradiation resulted in FITC uptake by retinal cells. In addition, similar experiments with Cy3-siRNA clearly show that the technique can effectively deliver siRNA into RGCs. Importantly, neither AuNP intravitreal injection nor irradiation resulted in RGC death, as determined by RBPMS quantification 1 week following AuNP injection and/or irradiation. Since living biological tissues absorb energy very weakly at 800nm, this non-invasive tool may provide a safe, cost effective approach to selectively target retinal cells and limit complications associated with surgical interventions, and potential biological hazards associated with viral-based gene therapy. In addition, given the extensive use of lasers in ophthalmic practice, our proposed technology may be seamlessly inserted to current clinical setups. (1) E. Bergeron et al, Nanoscale, 7, 17836 (2015).
Optical coherence tomography (OCT) imaging has become a standard diagnostic tool in ophthalmology, providing essential information associated with various eye diseases. In order to investigate the dynamics of the ocular fundus, we present a simple and accurate automated algorithm to segment the inner limiting membrane in video-rate optic nerve head spectral domain (SD) OCT images. The method is based on morphological operations including a two-step contrast enhancement technique, proving to be very robust when dealing with low signal-to-noise ratio images and pathological eyes. An analysis algorithm was also developed to measure neuroretinal tissue deformation from the segmented retinal profiles. The performance of the algorithm is demonstrated, and deformation results are presented for healthy and glaucomatous eyes.
Spatial distributions of proteins are crucial for development, growth and normal life of organisms. Position of cells in a
morphogen gradient determines their differentiation in a specific manner. Neutrophils are the initial responders to
bacterial infection or other inflammatory stimuli and have the ability to migrate rapidly up shallow gradients of
attractants in vivo. Moreover, for the correct wiring of the nervous system, axonal growth cones detect concentration
changes of specific proteins called guidance cues to navigate and reach their targets. Guidance cues can either be
chemoattractive or chemorepulsive, and the same protein can act successively as both depending on the time point in
development or the simultaneous presence of other molecules. A prerequisite to understand chemotaxis in a precise
manner is the availability of a method able to reproduce in vitro the spatial distributions of proteins found in vivo. We
recently introduced LAPAP (Laser-assisted protein adsoption by photobleaching), an optical method to produce
substrate-bound protein patterns with micron resolution. Here, we present how the amount of protein present on the
pattern can be increased by one order of magnitude.
Conference Committee Involvement (1)
Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XVI
24 January 2011 | San Francisco, California, United States