Lipid/Polyelectrolyte coatings to control carbon nanotubes intracellular distribution

On-Demand Chemomagnetic Modulation of Striatal Neurons Facilitated by Hybrid Magnetic Nanoparticles

Minimally invasive manipulation of cell signaling is critical in basic neuroscience research and in developing therapies for neurological disorders. Here, we describe a wireless chemomagnetic neuromodulation platform for the on-demand control of primary striatal neurons that relies on nanoscale heating events. Iron oxide magnetic nanoparticles (MNPs) are functionally coated with thermoresponsive poly (oligo (ethylene glycol) methyl ether methacrylate) (POEGMA) brushes loaded with dopamine. Dopamine loaded MNPs-POEGMA are co-cultured with primary striatal neurons. When alternating magnetinec fields (AMF) are applied, MNPs undergo hysteresis power loss and dissipate heat. The local heat produced by MNPs initiates a thermodynamic phase transition on POEGMA brushes resulting in polymer collapse and dopamine release. AMF-triggered dopamine release enhances the response of dopamine ion channels expressed on the cell membranes enhancing the activity of ~50% of striatal neurons subjected to the treatment. Chemomagnetic actuation on dopamine receptors is confirmed by blocking D1 and D2 receptors. The reversible thermodynamic phase transition of POEGMA brushes allow the on-demand release of dopamine in multiple microdoses. AMF-triggered dopamine release from MNPs-POEGMA causes no cell cytotoxicity nor promotes cell ROS production. This research represents a fundamental step forward for the chemomagnetic control of neural activity using hybrid magnetic nanomaterials with tailored physical properties.

Selective nuclear localization of siRNA by metallic versus semiconducting single wall carbon nanotubes in keratinocytes

BACKGROUND

The potential use of carbon nanotubes (CNTs) in gene therapy as delivery systems for nucleic acids has been recently recognized. Here, we describe that metallic versus semiconducting single-wall CNTs can produce significant differences in transfection rate and cellular distribution of siRNA in murine PAM212 keratinocytes.

RESULTS/METHODOLOGY

The results of cell interaction studies, coupled with supportive computational simulations and ultrastructural studies revealed that the use of metallic single wall CNTs resulted in siRNA delivery into both the cytoplasm and nucleus of keratinocytes, whereas semiconducting CNTs resulted in delivery only to the cytoplasm.

CONCLUSION

Using enriched fractions of metallic or semiconducting CNTs for siRNA complex preparation may provide specific subcellular targeting advantages.

A quantitative study of the intracellular concentration of graphene/noble metal nanoparticle composites and their cytotoxicity

Noble-metal nanoparticles (NPs) especially prepared from gold and silver have been combined on the surface of graphene to obtain graphene-based nanocomposites for novel functions in enhanced performance in bio-imaging, cancer detection and therapy. However, little is known about their cellular uptake, especially the intracellular quantity which plays a critical role in determining their functions and safety. Therefore, we prepared covalently conjugated GO/Au and GO/Ag composites by immobilizing Au and Ag nanoparticles on GO sheets pre-functionalized with disulfide bonds, respectively. The cellular uptake of these composites was quantitatively studied by means of an ion beam microscope (IBM) to determine the metal content in human lung cancer cells (A549 cells) and liver hepatocellular carcinoma cells (HepG2 cells). The cell uptake was also studied by inductively coupled plasma mass spectrometry (ICP-MS), which is one of the most sensitive techniques being applied to cell suspensions, for comparison. Toxicity, one of the consequences of cellular uptake of GO based composites, was studied as well. The potential toxicity mechanism was also suggested based on the results of intracellular quantification of the nanomaterials.