Drug Delivery

    Effective delivery of small and large bio-molecules into cells for therapeutic purposes is challenging, owing to the fact that lots of these molecules cannot freely penetrate through the cell membrane. Large bio-molecules delivery such as proteins is further exacerbated by their inability to escape cellular endosomes. In the Rotello Research Group, we use functionalized gold nanoparticles (AuNPs) and nanoparticles-stabilized capsules (NPSCs) to deliver small molecule drugs as well as bio-molecules such as siRNA, genes and proteins, alone or in combination, into mammalian cells. Research is also on progress to deliver such molecules into animals to treat certain diseases.

  • Protein Delivery
  • Using gold nanoparticle-stabilized capsules (NPSCs), we reported a general strategy for direct delivery of functional proteins into the cytosol. These NPSCs are formed and stabilized through supramolecular interactions between the nanoparticles, the protein cargo, and the fatty acid capsule interior. The NPSCs are ∼130 nm in diameter, and feature low cytotoxicity and excellent serum stability. The effectiveness of these NPSCs as therapeutic protein carriers was demonstrated through the delivery of fully functional caspase-3 to HeLa cells with concomitant apoptosis. Analogous delivery of green fluoresecent protein (GFP) confirmed cytosolic delivery. We also delivered organelle-specific (peroxisome specific) proteins, demonstrating the utility of the system for both therapeutic and imaging applications.

    A) Schemes for intracellular protein delivery. B) GFP delivered into HeLa cells. C) GFP-PTS1 delivered into the peroxisomes of HeLa cells.

  • Monitoring Nanoparticles in vivo
  • The effective use of NPs in drug delivery applications requires new analytical tools to quantify the NPs in cells, monitor their stabilities, and generate images of their biodistributions. In our research, we have developed a laser desorption/ionization mass spectrometry (LDI-MS) method for multiplexed detection of NPs. In this method, it tracks NPs by measuring their surface ligands, which typically control their chemistry in vivo. Recently, we used this technique to monitor AuNPs in mouse tissue samples. The LDI-MS images provide sub-organ distribution information of multiple AuNPs injected into the same mouse. We find that the surface chemistry of AuNPs largely affect their intra-organ distributions.

    Scheme of the LDI-MS imaging strategy to obtain the biodistributions of AuNPs in mouse tissues.

  • Delivery of Therapeutic Gold Nanoparticles
  • Delivering therapeutic nanoparticles into cells and subsequently making them supramolecularly interact with the complementary component is challenging, due to the complex cellular environments. In our research, we used a host-guest system featuring diaminohexane-terminated gold nanoparticles (AuNP–NH2) and complementary cucurbit[7]uril (CB[7]). In this system, threading of CB[7] on the particle surface reduced the cytotoxicity of AuNP-NH2 through sequestration of the particles in endosomes. Intracellular triggering of the therapeutic effect of AuNP-NH2 was then achieved through the administration of 1-adamantylamine (ADA), removing CB[7] from the nanoparticles surface, causing the endosomal release and concomitant in situ cytotoxicity of AuNP-NH2. This supramolecular strategy for intracellular activation provides a new tool for potential therapeutic applications.

    Delivery of gold nanoparticles (AuNP-NH2-CB[7]) into cells, and subsequently releasing them from the endosome to the cytosol by adding ADA.

    Selected References:

    1) Tang, R.; Kim, C. S.; Solfiell, D. J.; Rana, S.; Mout, R.; Velázquez-Delgado, E. M.; Chompoosor, A.; Jeong, Y.; Yan, B.; Zhu, Z.-J.; Kim, C.; Hardy, J. A.; Rotello, V. M. “Direct Delivery of Functional Proteins and Enzymes to the Cytosol Using Nanoparticle-stabilized Nanocapsules” ACS Nano 2013, 7, 6667-6673.
    2) Zhu, Z.-J.; Yeh, Y.-C.; Tang, R.; Yan, B.; Tamayo, J.; Vachet, R. W.; Rotello, V. M. “Stability of Quantum Dots in Live Cells” Nat. Chem. 2011, 3, 963-968.
    3) Yan, B.; Kim, S. T.; Kim, C. S.; Saha, K.; Moyano, D. F.; Xing, Y.; Jiang, Y.; Roberts, A. L.; Alfonso, F. S.; Rotello, V. M., Vachet, R. W. “Multiplexed Imaging of Nanoparticles in Tissues using Laser Desorption/Ionization Mass Spectrometry” J. Am. Chem. Soc. 2013, 135, 12564-12567.
    4) Kim, C.; Agasti, S. S.; Zhu, Z.-J.; Isaacs, L.; Rotello, V. M. “Recognition-mediated Activation of Therapeutic Gold Nanoparticles inside Living Cells” Nat. Chem. 2010, 2, 962-966.