tissues like choriocapillaris and RPE can be achieved using thermosensitive liposomes (32). Light-targeted liposomal delivery can be employed for diagnosis and therapy of CNV in age-related macular degeneration (ARMD). In this approach, after the systemic administration of thermosensitive liposomes, drug release in CNV and surrounding tissues is triggered by local warming of the tissue and liposomes using a light beam at a wavelength strongly absorbed by blood.

Nanorods, Nanotubes, and Nanofibers

These are cylindrical structures, with diameters typically in the nanometer range. Unlike nanotubes, which have a hollow interior, nanorods have a solid interior. Compared to nanorods, nanofibers are longer and more flexible. Nanofibers can have a solid or hollow interior. These nanosystems can be applied to a broad range of areas including biosensors, catalysis, drug delivery, and optoelectronics. Carbon nanotubes are one of the most investigated nanotube-based systems. Carbon nanotubes conduct electric signals, allowing their application in nanoelectronics (33,34). More recently, carbon nanotubes have been employed for several biological applications. Carbon nanotubes can be used as cytotoxic nanobombs for inducing cancer cell death (35), for highly selective detection of cancer biomarkers (36), and as tissue-engineering platforms for neuronal growth (37,38) and bone repair (39,40). Potent nanobombs can be created by adsorbing water molecules on single-wall carbon nanotube sheets. These nanotubes can be made to explode by causing rapid evaporation of adsorbed water molecules, with the generation of enormous pressure in nanotubes, by exposure to a 800 nm laser of 50200 mW/cm2 intensity. Neurons cultured on these nanotubes exhibit extensive branching neurites (38). Embryonic hippocampal neurons cultured on carbon nanotubes coupled to 4-hydroxynonenal (4-HNE), elaborated four to six neurites as compared to just one or two neurites of neurons cultured on untreated nanotubes. Total neurite length also increased more than twofold with 4-HNE-treated nanotubes. This, in conjunction with their ability to support neuronal growth and conduct electric signals, can be potentially employed in the development of retinal prostheses.

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