TR Pink Mod3 Research Proposal
Nanoparticles offer new methods of imaging and treating cancer. By developing new invasive strategies, we can increase the efficiency of targeting and delivery of these nanoparticles to cancer cells. The structure of a nanoparticle is important in determining its circulating half life. One factor that affects clearance is the amount of PEGylation on the surface of a nanoparticle. One paper studies and determines the optimal MW and density of these PEG polymers for best nanoparticles delivery. Modifications can also be made on a nanoparticle to influence it's targeting behavior. We will use aptamer-conjugated nanoparticle VAP7 to target a VEGF receptor, which is overexpressed in many cancer cells. However, because aptamers are also conjugated to the surface of the nanoparticles along with the PEG chains and other modifications, we want to see if the use of aptamers will affect the optimal PEG densities previously measured.
Background Information to be Provided in Presentation
- Engineering nanoparticles to optimize clearance and targeting
- Barreto, J., Malley, W., Kubeil, M., Graham, B., Stephan, H., & Spiccia, L. (2011). Nanomaterials: Applications in Cancer Imaging and Therapy. Adv. Mater., 23, H18-H40.
- He, Q., Zhang, J., Zhu, Z., Zhang, L., Bu, W., Guo, L., & Chen, Y. (2010). The Effect of PEGylation of Mesoporous Silica Nanoparticles on Nonspecific Binding of Serum Proteins and Cellular Responses. Biomaterials, 31, 1085-1092.
- Farokhzad, O., Jon, S., Khademhosseini, A., et al. (2004). Nanoparticle-Aptamer Bioconjugates: A New Approach for Targeting Prostate Cancer Cells. Cancer Research, 64, 7668-7672.
- Bergen, J., Recum, H.A., Goodman, T., Massey, A., Pun, S. (2006). Gold Nanoparticles as a Versatile Platform for Optimizing Physicochemical Parameters for Targeted Drug Delivery. Macromol. Biosci., 6, 506-516.
- Nonaka, Y., Sode, K., & Ikebukuro, K. (2010). Screening and Improvement of an Anti-VEGF DNA Aptamer. Molecules, 15, 215-225.
We will study the affect of aptamers on the optimal PEGylation density in aptamer-conjugated nanoparticles. We want to find the optimal density to maximize nanoparticle delivery.
Project Details and Methods
We will study the circulation characteristics of 50nm negatively charged gold colloid nanoparticles with a surface charge of about -30mV
- Gold nanoparticles will be synthesized through reduction of tetrachloroauric acid with sodium citrate
- Conjugation with SH-PEG-COOH will occur by treatment of nanoparticle solution with excess PEG chains of varying molecular weights (4,6,10,20 kDa)
- Addition of the Vap7 aptamer will occur through covalent linkage following NHS ester activation by EDC
- HSA assay will measure nonspecific binding characteristics
- Phagocytosis in THP-1 macrophages will be quantified
- Hemolysis assay will give insight into toxicity of conjugated nanoparticles