Colloids and Surfaces B: Biointerfaces 152 (2017) 18–28 Contents lists available at ScienceDirect Colloids and Surfaces B: Biointerfaces jo ur nal ho me p ag e: www.elsevier.com/locate/colsurfb Influence of core and maltose surface modification of PEIs on their interaction with plasma proteins—Human serum albumin and lysozyme Dominika Wrobel a,∗ , Monika Marcinkowska b , Anna Janaszewska b , Dietmar Appelhans c , Brigitte Voit c , Barbara Klajnert-Maculewicz b,c , Maria Bryszewska b , Marcel ˇ Stofik a , Regina Herma a , Piotr Duchnowicz d , Jan Maly a a Department of Biology, Jan Evangelista Purkinje University, Usti nad Labem, Czechia b Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland c Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069, Dresden, Germany d Department of Biophysics of Environmental Pollution, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland a r t i c l e i n f o Article history: Received 6 October 2016 Received in revised form 10 December 2016 Accepted 31 December 2016 Available online 2 January 2017 Keywords: Dendritic glycopolymer Proteins Blood Plasma Protein structure Fluorescence quenching a b s t r a c t Regardless of the route of administration, some or all of a therapeutic agent will appear in the blood stream, where it can act on blood cells and other components of the plasma. Recently we have shown that poly(ethylene imines) (PEIs) which interact with plasma proteins are taken up into erythrocyte membranes. These observations led us to investigate the interactions between maltose functionalized hyperbranched PEIs (PEI-Mal) and plasma proteins. Two model proteins were chosen - human serum albumin (HSA) (albumins constitute ∼60% of all plasma proteins), and lysozyme. HSA is a negatively charged 66 kDa protein at neutral pH, whereas lysozyme is a positively charged 14 kDa protein. Fluo- rescence quenching and changes in the conformation of the amino acid tryptophan, diameter and zeta potential of proteins were investigated to evaluate the interaction of PEI-Mal with proteins. PEI-Mal interacts with both types of proteins. The strength of dendritic glycopolymer interactions was generally weak, especially with lysozyme. Greater changes were found with HSA, mainly triggered by hydrogen bonds and the electrostatic interaction properties of dendritic glycopolymers. Moreover, the structure and the size of PEI-Mal macromolecules affected these interactions; larger macromolecules with more sugar groups (95% maltose units) interacted more strongly with proteins than smaller ones with lower sugar modification (33% maltose units). Due to (i) the proven overall low toxicity of sugar-modified PEIs and, (ii) their ability to interact preferentially through hydrogen bonds with proteins of human plasma or possibly with other interesting protein targets, PEI-Mal is a good candidate for creating therapeutic nanoparticles in the fast developing field of nanomedicine. © 2017 Elsevier B.V. All rights reserved. 1. Introduction The immediate presence of drug molecules in the blood stream results in protein interactions. Similarly, interactions of nanoparti- cles with plasma proteins have recently been in focus and widely discussed [1–5]. Two commonly accepted models of interactions were proposed that describe this phenomena. The first is called the ‘protein corona’, where proteins form a corona surrounding a ∗ Corresponding author at: Jan Evangelista Purkyne University, Department of Biology, Ceske mladeze 8, 400 96 Usti nad Labem, Czechia. E-mail address: dominika.wrobel@ujep.cz (D. Wrobel). nanoparticle. The second model, where small nanoparticles create the corona on the protein surface, it is usually called a ‘nanopar- ticles corona’. The nature and type of those typical interactions depend on the macromolecular functional surface groups, and their size, shape, flexibility and architecture [6]. Several different protein-nanoparticle interaction mechanisms have been described as electrostatic or van der Waal’s forces, but also as hydrophobic interactions or hydrogen bonds [2,4]. Moreover, protein adsorp- tion on a nanoparticle surface is important in the distribution and delivery efficiency of biologically-active materials [3]. In our previous studies, the toxic influence of maltose function- alized hyperbranched PEI (PEI-Mal) nanoparticles on red blood cells was significantly decreased in experiments carried out in blood http://dx.doi.org/10.1016/j.colsurfb.2016.12.042 0927-7765/© 2017 Elsevier B.V. All rights reserved.