Quantum dots as fluorescent bio‐labels in cancer diagnostic

Abstract

In this work we present and discuss some results concerning the application of colloidal semiconductor quantum dots for cancer diagnostic. We have prepared and applied different core-shell semiconductor quantum dots such as Cadmium Teluride-Cadmium Sulfide (CdTe-CdS) and Cadmium SulfideCadmium Hydroxide (CdS/Cd(OH) 2 ). For the purpose of diagnostic with living cells, the CdS/Cd(OH) 2 presented best results, maintaining high levels of luminescence as well high stability in biological media. The quantum dots were obtained in aqueous medium, by reacting Cd 2+ and S 2-in the presence of sodium polyphosphate as the stabilizing agent. Subsequent surface passivation with Cd(OH) 2 was carried out to improve luminescence. At a pH of 7,2 the quantum dots were functionalized with a 0.01% glutaraldehyde solution and then, incubated with living healthy and neoplastic cells (glial, glioblastoms and cervical) and tissues (breast) in culture medium. Tissue and cell staining were evaluated by the laser scanning confocal microscopy. Fluorescence Microscopy was used as a primary tool in order to explore the labeling of the samples. The procedure presented in this work, shown to be very efficient as a potential tool for fast and precise cancer diagnostic.

In vitro and in vivo documentation of quantum dots labeled Trypanosoma cruzi–Rhodnius prolixus interaction using confocal microscopy

“…Herein, we demonstrate that QDs prepared in our own facilities were successfully used for imaging of living parasites and interaction studies. Others studies with living cells as macrophages , yeast cells (Farias et al 2007) and also quantum dots as fluorescent biolabel in cancer diagnostic (Farias et al 2006), showed the low level of cytotoxity of this material in comparison with others fluorophores.…”

Three-Pulse Photon Echo Peak Shift Measurements of Capped CdSe Quantum Dots

“…The recent intense interest in semiconductor nanocrystalline quantum dots (QDs) stems from the fascinating optical properties exhibited by these systems, most notably their size-tunable absorption and emission. QDs have been investigated for numerous applications including lasing media, [1][2][3][4] biolabeling, [5][6][7] solar cells, [8][9][10] and quantum information storage. [11][12][13] One interesting property of QDs is the observation of fluorescence intermittency or blinking, 14 which can be understood in terms of surface defects or trap states.…”

“…The recent intense interest in semiconductor nanocrystalline quantum dots (QDs) stems from the fascinating optical properties exhibited by these systems, most notably their size-tunable absorption and emission. QDs have been investigated for numerous applications including lasing media, − biolabeling, − solar cells, − and quantum information storage. − …”

Quantum Dot Enabled Molecular Sensing and Diagnostics

“…This ultimately requires detailed inspections of biomolecules as well as their interactions with other molecules and the environment 9 . Fluorescence based methods suit the aforementioned goals perfectly by providing sensitive, reproducible, and quantitative detection of target molecules 6 , 10 - 12 .…”