Improving cell penetration of gold nanorods by using an amphipathic arginine rich peptide

Introduction: Gold nanorods are highly reactive, have a large surface-to-volume ratio, and can be functionalized with biomolecules. Gold nanorods can absorb infrared electromagnetic radiation, which is subsequently dispersed as local heat. Gold nanoparticles can be used as powerful tools for the diagnosis and therapy of different diseases. To improve the biological barrier permeation of nanoparticles with low cytotoxicity, in this study, we conjugated gold nanorods with cell-penetrating peptides (oligoarginines) and with the amphipathic peptide CLPFFD. Methods: We studied the interaction of the functionalized gold nanorods with biological membrane models (liposomes) by dynamic light scattering, transmission electron microscopy and the Langmuir balance. Furthermore, we evaluated the effects on cell viability and permeability with an MTS assay and TEM. Results and Discussion: The interaction study by DLS, the Langmuir balance and cryo-TEM support that GNR-Arg₇ CLPFFD enhances the interactions between GNRs and biological membranes. In addition, cells treated with GNR-Arg₇ CLPFFD internalized 80% more nanoparticles than cells treated with GNR alone and did not induce cell damage. Conclusion: Our results indicate that incorporation of an amphipathic sequence into oligoarginines for the functionalization of gold nanorods enhances biological membrane nanoparticle interactions and nanoparticle cell permeability with respect to nanorods functionalized with oligoarginine. Overall, functionalized gold nanorods with amphipathic arginine rich peptides might be candidates for improving drug delivery by facilitating biological barrier permeation.