New approach for time-resolved and dynamic investigations on nanoparticles agglomeration

  • PDF / 3,160,330 Bytes
  • 10 Pages / 612 x 808 pts Page_size
  • 82 Downloads / 153 Views

DOWNLOAD

REPORT


Center for X-ray Analytics, Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen 9014, Switzerland Laboratory of Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen 9014, Switzerland 3 Department of Chemistry, University of Fribourg, Chemin du Musée, Fribourg 1700, Switzerland 4 Laboratory for Biomimetic Membranes and Textiles, Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen 9014, Switzerland 5 Department of Environmental Systems Science, Swiss Federal Institute of Technology, ETH-Zurich, Zurich 8092, Switzerland 6 Institute of Materials, EPFL, Lausanne 1015, Switzerland 7 Cellular and Biomedical Sciences, Faculty of Medicine, University of Bern, Bern 3012, Switzerland 2

© The Author(s) 2020 Received: 13 April 2020 / Revised: 16 June 2020 / Accepted: 17 June 2020

ABSTRACT Nanoparticle (NP) colloidal stability plays a crucial role in biomedical application not only for human and environmental safety but also for NP efficiency and functionality. NP agglomeration is considered as a possible process in monodispersed NP colloidal solutions, which drastically affects colloidal stability. This process is triggered by changes in the physicochemical properties of the surrounding media, such as ionic strength (IS), pH value, or presence of biomolecules. Despite different available characterization methods for nanoparticles (NPs), there is a lack of information about the underlying mechanisms at the early stage of dynamic behaviors, namely changing in NP size distribution and structure while placing them from a stable colloidal solution to a new media like biological fluids. In this study, an advanced in situ approach is presented that combines small angle X-ray scattering (SAXS) and microfluidics, allowing label-free, direct, time-resolved, and dynamic observations of the early stage of NP interaction/agglomeration initiated by environmental changes. It is shown for silica NPs that the presence of protein in the media enormously accelerates the NP agglomeration process compared to respective changes in IS and pH. High IS results in a staring agglomeration process after 40 min, though, in case of protein presence in media, this time decreased enormously to 48 s. These time scales show that this method is sensitive and precise in depicting the dynamics of fast and slow NP interactions in colloidal conditions and therefore supports understanding the colloidal stability of NPs in various media concluding in safe and efficient NP designing for various applications.

KEYWORDS microfluidic small-angle X-ray scattering (SAXS), in situ, dynamic measurements, nanoparticle agglomeration, biological environment, label-free

1

Introduction

Colloidal stability is a crucial parameter in the efficacy and safety of colloidal nanoparticles (NPs) in various applications [1]. Minor changes in the physicochemical properties of NP media can have a tremendous influence on stability, and thereby can dominate NP functionalit