Cellular imaging using biocompatible dendrimer-functionalized graphene oxide-based fluorescent probe anchored with magnetic nanoparticles.

We describe a novel multicomponent graphene nanostructured system that is biocompatible, and has strong NIR optical absorbance and superparamagnetic properties. The fabrication of the multicomponent nanostructure system involves the covalent attachment of 3 components; Fe(3)O(4)(Fe) nanoparticles, PAMAM-G4-NH(2) (G4) dendrimer and Cy5 (Cy) on a graphene oxide (GO) surface to synthesize a biologically relevant multifunctional system. The resultant GO-G4-Fe-Cy nanosystem exhibits high dispersion in an aqueous medium, and is magnetically responsive and fluorescent. In vitro experiments provide a clear indication of successful uptake of the GO-G4-Fe-Cy nanosystem by MCF-7 breast cancer cells, and it is seen to behave as a bright and stable fluorescent marker. The study also reveals varied cellular distribution kinetics profile for the GO nanostructured system compared to free Cy. Furthermore, the newly developed GO nanostructured system is observed to be non-toxic to MDA-MB-231 cell growth, in striking contrast to free G4 dendrimer and GO-G4 conjugate. The GO-G4-Fe-Cy nanostructured system characterized by multifunctionality suggests the merits of graphene for cellular bioimaging and the delivery of bioactives.

Reactive Silver Oxalate Ink Composition with Enhanced Curing Conditions for Flexible Substrates.

A solid silver-ligand complex, µ-oxolato-bis(ethylenediaminesilver(I)), was developed for formulating particle-free conductive metal-organic decomposition (MOD) inkjet inks. The complex comprises both a high molar silver content and solubility in inkjet compatible polar solvents. An aqueous ink formulation with 29.5 wt % silver content was developed and inkjet printed onto glass, polyethylene terephthalate, and polyimide substrates. A new hybrid thermal-photonic curing approach resulting in substantially improved electrical properties and substrate adhesion is presented. Silver conductive traces were measured to have bulk resistivity of 4.26 × 10-8 Ω m, which is 2.7 times that of bulk silver. One-pot complex synthesis yielded an easily isolated, and stable, solid product that can be formulated when needed thereby improving shelf life.

Self-propelled carbon nanotube based microrockets for rapid capture and isolation of circulating tumor cells.

Here, we report a non-invasive strategy for isolating cancer cells by autonomously propelled carbon nanotube (CNT) microrockets. H2O2-driven oxygen (O2) bubble-propelled microrockets were synthesized using CNT and Fe3O4 nanoparticles in the inner surface and covalently conjugating transferrin on the outer surface. Results show that self-propellant microrockets can specifically capture cancer cells.

Structure effect of carbon nanovectors in regulation of cellular responses.

Carbon nanostructures such as multiwalled carbon nanotubes (CNT) and graphene (G) are potential candidates in a large number of biomedical applications. However, there is limited understanding and connection between the physicochemical properties of diverse carbon nanostructures and biological systems, particularly with regard to cellular responses. It is also crucial to understand how the structure and surface composition of carbon nanostructures affect the cellular internalization process. Here, through in vitro cellular entry kinetics and cytotoxicity studies using MCF-7 breast cancer cells and H460 human lung cancer cells, we show that the structure and surface composition of CNT and G conjugates with various molecules such as PAMAM dendrimers (G4) and G4-poly(ethylene glycol) (PEG) are directly related to their cellular internalization ability and toxicity. Interestingly, the cellular association of CNT and G nanoconjugates was observed to be structure and surface composition dependent. We found that CNT conjugates internalized more compared to G conjugates. Furthermore, G4 conjugated CNT internalized more compared to G4-PEG conjugated CNT, whereas, higher internalization was found for G4-PEG conjugated G than G4 conjugated G. We have also correlated the cytotoxicity and cellular uptake mechanisms of CNT, G, and their conjugates through zeta potential measurements, fluorescence quenching studies and by fluorescence-activated cell sorting. Altogether these studies suggest different biological activities of the carbon nanostructures, with the shape and surface composition playing a primary role.