Synthesis of Size-Monodisperse CdS Nanocrystals Using Phosphatidylcholine Vesicles as True Reaction Compartments

Abstract

Phosphatidylcholine vesicles provide reaction compartments for synthesis of size-quantized CdS nanocrystals of dimension predicted to within 2.5 Å on the basis of initial encapsulated CdCl2 concentration and vesicle diameter. Vesicle formation by detergent dialysis of phosphatidylcholine/hexylglucoside mixed micelles yields highly monodisperse lipid capsules within which monodisperse CdS nanoparticles are precipitated with sulfide. Size-quantized CdS nanocrystals, with diameters ranging from 20 to 60 Å, have been produced with typical standard deviations about the mean diameter of ±8%, as measured by transmission electron microscopy. Spectrophotometric and photoluminescence spectra are consistent with highly crystalline, monodisperse particles with few core or surface defects. Measured exciton energies show excellent agreement with data in the literature. The empirical pseudopotential model presented by Krishna and Friesner for a cubic CdS lattice, correcting for experimentally measured lattice contractions, best fits the exciton energy versus particle diameter data.

Microfluidic hydrodynamic focusing based synthesis of POPC liposomes for model biological systems

“…Since their discovery in the 1960s [1], liposome application has spanned a wide range of fields. They have been used as gene and drug delivery vectors in the pharmaceutical industry [2][3][4][5], as contrast agent containers in enhanced medical imaging [6][7][8], and as nano-sized crystallization reactors [9,10]. Similarities in the chemical and physical properties of the lipid bilayers of liposomes and living cells have also led to their use as models in studying cellular membranes [1,11].…”

Nanoparticle Synthesis in Vesicle Microreactors

“…The reaction is then initiated when reactant B diffuses across the membrane. Actually, nearly all of the work reported in the literature is based on these two approaches (Korgel et al, 1996 andRalaeloff et al, 1985;Khramov et al, 1993). Up to now, there are only few reports on reactions realized via the fusion of two vesicles encapsulating reactant A and B, respectively (Model 3).…”

“…The synthesis in confined micro/nano-containers (Shchukin et al, 2004) can be divided into two main types: one involves exact templating where the product has the same shape and size as the container, and the other -not. Exact templating is usually achieved in SUVs and LUVs, and until now, nearly most of the reported syntheses of particles in the nanometer range have been realized in this way (Korgel et al, 1996 andRafaeloff et al, 1985;Khramov et al, 1993). However, in order to obtain a clear picture about bio-fabrication processes in cells with much bigger sizes e.g.…”

Novel synthesis of biologically active CdS nanoclusters in cell-mimicking vesicles

“…[20] For biological applications, the NCs must be coated with a biocompatible layer to improve photostability properties and minimise toxic side effects. In the past, only a few groups have used confined reaction vessels such as reverse micelles [21] and lipid vesicles [22] for the arrested precipitation of CdS nanoparticles (NPs). Vesicular systems are now being investigated as potential cell-mimicking systems because the bilayer encompassing such vesicles is structurally very similar to the cell membrane.…”