Single Quantum Dot-Micelles Coated with Silica Shell as Potentially Non-Cytotoxic Fluorescent Cell Tracers

Abstract

The present study describes a stabilization of single quantum dot (QD) micelles by hydrophobic silica precursors and an extension of the silica layer to form a silica shell around the micelle. The obtained product consists of up to 92% of single nanocrystals (CdSe, CdSe/ZnS, or CdSe/ZnSe/ZnS quantum dots) in the silica micelles, coated with silica shell. The thickness of silica shell could vary, starting from 3 to 4 nm. Increasing the shell thickness increases the photoluminescent characteristics of QDs in aqueous solution. The silica-shelled single CdSe/ZnS QD micelles possess a high quantum yield in aqueous solution, a controlled small size, sharp photoluminescence spectra (fwhm approximately 30 nm), an absence of aggregation, and a high transparency. The presence of a hydrophobic layer between the QD and silica shell ensures an incorporation of other hydrophobic molecules (with interesting properties) in the close proximity of nanocrystal. Thus, it is possible to combine the characteristics of hybrid material with the priority of small size. The nanoparticles are amino functionalized and ready for conjugation. A comparatively good biocompatibility is demonstrated. The nanoparticles show ability for intracellular delivery and are noncytotoxic during long-term incubation with viable cells in the absence of light exposure, which makes them appropriate for cell tracing and drug delivery.

Combined main-chain/side-chain ionic liquid crystalline polymer based on ‘jacketing’ effect: Design, synthesis, supra-molecular self-assembly and photophysical properties

“…Meanwhile, the emission peak intensity of poly (BImBHCS-X) (X" = Br", BF 4 ", PF 6 " and TFSI") was much stronger than that of PBBHCS. This indicated that the counter-anions inserted into the polymer samples hindered the strong high-ordering packing of the side chain biphenyl mesogens, which resulted in the absence of fluorescence quenching [66][67][68][69]. The fluorescence emission spectra results were consistent with the previous results describing the structures of the MCSC-ILCPs poly(BImBHCS-X).…”

Stabilized Porous Phospholipid Nanoshells

“…HeLa cells readily internalize nanoparticles of similar size to those used in this work, including 120 nm phospholipid vesicles, 50 nm gold nanoparticles and 18 nm silica nanoparticles. [35][36][37] Furthermore, EGFP fluorescence was stable within the cell in excess of two hours, suggesting that the PPN architecture protects the encapsulated components from intracellular proteases which may degrade the protein. Combined with PPN permeability and stability studies, these results strongly suggest the utility of polymerized PPNs for delivering enzymes and large molecular weight reporters to the intracellular environment and may represent a new paradigm for cellular analysis as well as diagnosis and treatment of disease.…”

Mesoporous Silica Nanoparticles for Drug Delivery and Biosensing Applications

“…[49] Furthermore, the ability to functionalize the surface of nanoparticles with large quantities of cell-recognition or other site-directing compounds makes them ideal agents for cell tracing. [50][51][52][53][54][55] In contrast to other solid nanoparticle biosensors, micro-and mesoporous silica provide two important unique advantages: 1) High porosity. The large surface areas and pore volumes allow the encapsulation/immobilization of large amounts of sensing molecules per particle for fast response times and low detection limits.…”