Investigating Possible Enzymatic Degradation on Polymer Shells around Inorganic Nanoparticles.

Lin Zhu,Beatriz Pelaz,Wolfgang Parak,Indranath Chakraborty

doi:10.3390/ijms20040935

Abstract

Inorganic iron oxide nanoparticle cores as model systems for inorganic nanoparticles were coated with shells of amphiphilic polymers, to which organic fluorophores were linked with different conjugation chemistries, including 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) chemistry and two types of “click chemistry”. The nanoparticle-dye conjugates were exposed to different enzymes/enzyme mixtures in order to investigate potential enzymatic degradation of the fluorophore-modified polymer shell. The release of the dyes and polymer fragments upon enzymatic digestion was quantified by using fluorescence spectroscopy. The data indicate that enzymatic cleavage of the fluorophore-modified organic surface coating around the inorganic nanoparticles in fact depends on the used conjugation chemistry, together with the types of enzymes to which the nanoparticle-dye conjugates are exposed.

Highlights

After in vitro or in vivo administration, nanoparticles (NPs) may be exposed to different local environments along their trajectory
Iron oxide was chosen due to its lower absorption in comparison, for example, to gold NPs of similar size, which facilitates quantification of the number of fluorophores linked per NP by absorption spectroscopy
At that point the Fe3O4 NPs were dissolved in hexane, and no zeta potential measurements in aqueous solution are possible of these iron oxide cores

Summary

Introduction

After in vitro or in vivo administration, nanoparticles (NPs) may be exposed to different local environments along their trajectory. Proteases present in endosomes/lysosomes may, for example, digest amphiphilic polymer coatings based on amide bonds [8]. There are some reports which describe enzyme-specific cleavage of distinct bonds present on the surface of NPs. in the present study we wanted to investigate this in more detail for one special case: Inorganic NPs (here, Fe3O4 NPs) coated with derivatives of the amphiphilic polymer poly-(isobutylene-alt-maleic anhydride)-graft-dodecyl (PMA) [19].

Results

Conclusion