Metallic Colloid Nanotechnology, Applications in Diagnosis and Therapeutics

Abstract

In recent years the fields of medicine and biology assist to an ever-growing innovation related to the development of nanotechnologies. In the pharmaceutical domain, for example, liposomes, polymer based micro and nanoparticles have been subjects of intense research and development during the last three decades. In this scenario metallic particles, which use was already suggested in the first half of the '80, are now experiencing a real renaissance. In the field of diagnosis, magnetic resonance imaging is one of the first and up to now the most developed application of metallic particles. But beside this application, a very new generation of biosensors based on the optical properties of colloidal gold and fluorescent nanocrystals, called quantum dots seems to be ready to be implemented in diagnosis and medical imaging. Concerning therapeutic applications, the potentialities of metal nanoparticles to help fulfilling the need of time and space controlled release of drugs has been intuited for a long time. Nowadays, magnetically guided carriers or thermal responsive matrices, in which drug release is triggered by the heating of metal nanoparticles, are effective examples of their application in drug delivery, while more recently efforts to develop metallic nanoobjects to be used as vectors of nucleic acids for vaccination and transfection have been multiplied. In the future, one of the most interesting challenges is certainly the use of metallic nanoparticles for an innovating, effective and selective physical treatment of solid tumors via targeted intracellular hyperthermia.

Dual Contrast Agent for Computed Tomography and Magnetic Resonance Hard Tissue Imaging

“…Still, the problem arising from the use of such heavy metal compounds, besides unspecific reactivity, is the lack of information about their metabolic destiny, possible accumulation, and toxicity after being released after CPC degradation. 16,17,30,31 In the current study, the concentration of both radiopacifiers was set at 5% wt/wt. The structural embedding of two nanoparticles types into the silica carrier beads prevents/inhibits their release as free metal ions, and allows even the encapsulation of much higher concentrations, while avoiding the above mentioned side effects.…”

“…Colloidal gold and iron oxide nanoparticles were selected as embedded agents for, respectively, CT and MR imaging, as both compounds are widely characterized and approved for clinical use. 16,17 After in vitro characterization, the developed contrast agent was tested in vivo, in a femoral condyle defect model in rats. Effects were monitored by scanning the same animals with both CT and MRI up to 8 weeks postsurgery.…”

Green Synthesis and Characterization of Gold Nanoparticles: Study of Its Biological Mechanism in Human SUDHL-4 Cell Line

“…The new or modern nanotechnology embraces all the medical clinical application, green synthesis technique and improvements made in the new nanotechnological process [9]- [11]. In recent years, synthesis of nanoparticles by using plants is gaining importance due to its effortlessness and eco-friendless [11]- [13].…”

Surface plasmon assisted electron acceleration in photoemission from gold nanopillars

“…For a short amount of time, these electrons oscillate in phase with each other and create a strongly enhanced electric field at the surface of the metal/vacuum or metal/dielectric interface 2,3 . SPRs have enormous potential for applications in medicine, communications, and electronics 4,5 , most of which take advantage of the strongly enhanced electric field created by the plasmon at the metal surface. Techniques such as surfaceenhanced Raman spectroscopy exploit this near field enhancement to allow the sensitive spectroscopic detection of single molecules 6 .…”