On the mechanical stability of polymeric microcontainers functionalized with nanoparticles
ABSTRACT We present key factors that influence the mechanical stability of polyelectrolyte/nanoparticle composite microcontainers and their encapsulation behavior by thermal shrinkage. Poly(diallyldimethylammonium chloride) (PDADMAC), poly(styrenesulfonate) (PSS) microshells and citrate-stabilized gold nanoparticles are used. The presence of nanoparticles in the microshell renders the encapsulation process by heat-shrinking more difficult. The encapsulation efficiency is found to decrease as the concentration of material to be encapsulated increases. Increasing nanoparticle content in the microshell or the concentration of dextran increases the likelihood of getting fused and damaged capsules during encapsulation. On the other hand, mechanical studies show that doping microshells with gold nanoparticles significantly increases their stiffness and resistance to deformation. Internalization of capsules by cells supports that the incorporation of metal nanoparticles makes the shells more resistant to deformation. This work provides information of significant interest for the potential biomedical applications of polymeric microshells such as intracellular storage and delivery.
SourceAvailable from: Huajian Gao[Show abstract] [Hide abstract]
ABSTRACT: Nanocapsules that can be tailored intelligently and specifically have drawn considerable attention in the fields of drug delivery and bioimaging. Here we conduct a theoretical study on cell uptake of a spherical nanocapsule which is modeled as a linear elastic solid thin shell in three dimensions. It is found that there exist five wrapping phases based on the stability of three wrapping states: no wrapping, partial wrapping and full wrapping. The wrapping phase diagrams are strongly dependent on the capsule size, adhesion energy, cell membrane tension, and bending rigidity ratio between the capsule and membrane. Discussion is made on similarities and differences between the cell uptake of solid nanocapsules and fluid vesicles. The reported results may have important implications on biomedical applications of nanotechnology.Soft Matter 12/2014; 11(6). DOI:10.1039/C4SM02427C · 4.15 Impact Factor
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ABSTRACT: Fast and quantitative adsorption of molecules may confer hybrid microcapsules high performance in specific applications, such as biocatalysis, biosensing, drug delivery, and so on. Engineering the chemical/topological structures of the capsule wall renders great potential to achieve this goal. In the present study, flower-like microcapsules are prepared through a biomimetic mineralization approach. Briefly, protein-hybrid microflowers are firstly synthesized through enzyme-induced precipitation of Cu3(PO4)2, which are subsequently utilized as templates for alternative deposition of the protamine layer and the silica layer through biomimetic silicification assisted by layer-by-layer (LbL) assembly. After treatment with EDTA, the flower-like protamine/silica hybrid (FPSH) microcapsules are obtained. Additionally, the hybrid capsule wall also endows the FPSH microcapsules with desirable pH, temperature and storage stability. Hopefully, our approach may provide a promising alternative to increase the efficiency of catalysis, drug delivery, etc.06/2014; 2(27). DOI:10.1039/C4TB00507D
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ABSTRACT: Particle-based fluorescence sensors for the quantification of specific ions can be made by coupling ion-sensitive fluorophores to carrier particles, or by using intrinsically fluorescent particles whose fluorescence properties depend on the concentration of the ions. Despite the advantages of such particle-based sensors for the quantitative detection of ions, such as the possibility to tune the surface chemistry and thus entry portal of the sensor particles to cells, they have also some associated problems. Problems involve for example crosstalk of the ion-sensitive fluorescence read-out with pH, or spectral overlap of the emission spectra of different fluorescent particles in multiplexing formats. Here the benefits of using particle-based fluorescence sensors, their limitations and strategies to overcome these limitations will be described and exemplified with selected examples.Current Opinion in Pharmacology 09/2014; 18:98–103. DOI:10.1016/j.coph.2014.09.011 · 4.23 Impact Factor