GERARDO BYK¹*, RAZ KHANDADASH¹, ARYEH WEISS², YUVAL EBENSTEIN³, YOAV GOTHILF⁴, VICTORIA MACHTEY^1,2
*Corresponding author
1. Bar Ilan University, Dept. of Chemistry, Laboratory of Nano-Biotechnology, Ramat Gan 52900, Israel
2. Bar Ilan University, School of Engineering, Ramat Gan, 52900, Israel
3. Tel Aviv University, School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences,
Tel-Aviv 69978, Israel
4. Tel-Aviv University, Dept. of Neurobiology, The George S. Wise Faculty of Life Sciences, and Sagol School of Neuroscience, Tel Aviv 69978, Israel

Abstract

We have developed new biocompatible, non-degradable NPs well tolerated both in vitro and in vivo with the particularity that peptide synthesis can be carried out on their surface. Although the NP’s have a large range of well-defined sizes going from 20 to 400 nm, they are all composed of the same monomers. Their shell composition, in contact with the biological media, is uniformly composed of polyethylene-glycol, thus their biocompatibility remains high along the different sizes. A proposed peculiar mechanism of formation allowed maintaining uniform their shell composition. The conjugation of molecules to the NPs was a real challenge since they are nano-hydrogels with high colloidal stability that can only be dialyzed for eventual removal of reagents. Therefore we have designed and proved a novel solid phase peptide synthesis method for Merrifield synthesis on nanoparticles based on the embedment of the NPs in a permeable and removable magnetic matrix. Overall, the platform composed of the NPs and the synthetic peptide is a useful tool for developing imaging methods for intracellular localization of the NPs using microscopy as we have shown in vitro for PC-3 cells, and for in vivo tracking using the Zebra fish model.

INTRODUCTION

The main motivation for synthesizing peptides on nanometric supports would be to use them in biological applications while linked to the NPs. The NPs serve as nucleation centers for the targeting ligand by increasing its local concentration, and as flags for tracking bio-relevant ligands exposed on their surface. A platform composed of a NP and a peptide synthesized on its surface, might be exploited for several biological applications such as in vitro/in vivo screening, high throughput screening or in vivo tracking. During the last 20 years, controlled peptide mixtures have been synthesized on macro-particles (beads) using various combinatorial approaches and screened “on-bead”-based in vitro assays for affinity to isolated proteins/antibodies with significant success (1-7). Nevertheless, these combinatorial systems had only a limited number of applications in live cells screening since the particle carrying the peptide is significantly bigger than cells. Finally, due to the nature and size of the particles carrying the peptides they were excluded from any in vivo application.
The synthesis of peptide ...