Dorota Bartczak

Preparation of peptide functionalized gold nanoparticles using one pot EDC/sulfo-NHS coupling

Although carbodiimides and succinimides are broadly employed for the formation of amide bonds (i.e., in amino acid coupling), their use in the coupling of peptides to water-soluble carboxylic-terminated colloidal gold nanoparticles remains challenging. In this article, we present an optimization study for the successful coupling of the KPQPRPLS peptide to spherical and rodlike colloidal gold nanoparticles. We show that the concentration, reaction time, and chemical environment are all critical to achieving the formation of robust, peptide-coated colloidal nanoparticles. Agarose gel electrophoresis was used for the characterization of conjugates.

Interactions of human endothelial cells with gold nanoparticles of different morphologies

The interactions between noncancerous, primary endothelial cells and gold nanoparticles with different morphologies but the same ligand capping are investigated. The endothelial cells are incubated with gold nanospheres, nanorods, hollow gold spheres, and core/shell silica/gold nanocrystals, which are coated with monocarboxy (1-mercaptoundec-11-yl) hexaethylene glycol (OEG). Cell viability studies show that all types of gold particles are noncytotoxic. The number of particles taken up by the cells is estimated using inductively coupled plasma (ICP), and are found to differ depending on particle morphology. The above results are discussed with respect to heating efficiency. Using experimental data reported earlier and theoretical model calculations which take into account the physical properties and distribution of particles in the cellular microenvironment, it is found that collective heating effects of several cells loaded with nanoparticles must be included to explain the observed viability of the endothelial cells.

Receptor-mediated interactions between colloidal gold nanoparticles and human umbilical vein endothelial cells.

A new strategy to manipulate cell operations is demonstrated, based on membrane-receptor-specific interactions between colloidal peptide-capped gold nanoparticles and human umbilical vein endothelial cells. It is shown that colloidal gold nanoparticles of similar charge and size but capped with different peptide sequences can deliberately trigger specific cell functions related to the important biological process of blood vessel growth known as angiogenesis. Specific binding of the peptide-capped particles to two endothelial-expressed receptors (VEGFR-1, NRP-1), which control angiogenesis, is achieved. The cellular fate of the functional nanoparticles is imaged and the influence of the different peptide-coated nanoparticles on the gene expression profile of hypoxia-related and angiogenic genes is monitored. The findings open up new avenues towards the deliberate biological control of cellular functions using strategically designed nanoparticles.

Laser-induced damage and recovery of plasmonically targeted human endothelial cells

Laser-induced techniques that employ the surface plasmon resonances of nanoparticles have recently been introduced as an effective therapeutic tool for destroying tumor cells. Here, we adopt a low-intensity laser-induced technique to manipulate the damage and repair of a vital category of noncancerous cells, human endothelial cells. Endothelial cells construct the interior of blood vessels and play a pivotal role in angiogenesis. The degree of damage and repair of the cells is shown to be influenced by laser illumination in the presence of gold nanoparticles of different morphologies, which either target the cellular membrane or are endocytosed. A pronounced influence of the plasmonic nanoparticle laser treatment on the expression of critical angiogenic genes is shown. Our results show that plasmon-mediated mild laser treatment, combined with specific targeting of cellular membranes, enables new routes for controlling cell permeability and gene regulation in endothelial cells.

Manipulation of in Vitro Angiogenesis Using Peptide-Coated Gold Nanoparticles

We demonstrate the deliberate activation or inhibition of invitro angiogenesis using functional peptide coated gold nanoparticles. The peptides, anchored to oligo-ethylene glycol capped gold nanospheres, were designed to selectively interact with cell receptors responsible for activation or inhibition of angiogenesis. The functional particles are shown to influence significantly the extent and morphology of vascular structures, without causing toxicity. Mechanistic studies show that the nanoparticles have the ability to alter the balance between naturally secreted pro- and anti-angiogenic factors, under various biological conditions. Nanoparticle-induced control over angiogenesis opens up new directions in targeted drug delivery and therapy.

Diacetylene-Containing Ligand As a New Capping Agent for the Preparation of Water-Soluble Colloidal Nanoparticles of Remarkable Stability

A new type of strategically designed functional ligands was used to cap gold nanocrystals and form robust colloidal nanoparticles, resistant to pH changes, temperature, and ionic strength variations as well as ligand-exchange reactions. The nanoparticles are coated with ligands that polymerize upon UV-irradiation, consequently embedding the particles in a stable organic shell. The ligand consists of an anchoring thiol group, which binds directly to the nanocrystal surface and two units, one hydrophobic and one hydrophilic. The hydrophobic alkyl unit contains a diacetylene group, which undergoes a 1,4-topochemical polymerization leading to a poly(enyne) structure during UV-irradiation. The hydrophilic unit contains an oligo-ethylene glycol chain, which ensures water solubility, and a terminal carboxylic group. Derived particles were characterized by transmission electron microscopy, surface enhanced Raman spectroscopy, and visible spectroscopy. Their stability was investigated and compared to particles capped with nonpolymerized ligands.

Programmed Assembly of Peptide-Functionalized Gold Nanoparticles on DNA Templates

We present a novel nanoparticle building block system based on the interactions between short synthetic oligonucleotides and peptides. Gold nanoparticles coated with DNA-binding peptides can be attached to self-organized oligonucleotide templates to formulate well-ordered structures of nanoparticles. By regulating the amount of DNA-binding peptide attached to the nanoparticle surface and using specifically designed oligonucleotides, the nanoparticle assembly can be controlled to form dimers, trimers, and adjustable-length nanoparticle chains as well as more complex structures.

Controlling the three-dimensional morphology of nanocrystals

We successfully demonstrate the morphological manipulation of complex three-dimensional gold nanocrystals. The control upon the nanoparticle crystal structure was achieved by the discovery of a new crystal growth kinetics regime where the number and length of arms as well as the nanocrystal size can be altered to produce a multitude of architectures. The synergetic relationship between chemical reaction components and possible mechanistic pathways is discussed. TEM tomography was employed to characterize the three-dimensional structure of the complex morphologies.

Gold Nanoparticles in Biomedical Applications

In this paper we report on the synthesis of robust water-soluble gold nanoparticles, suitable for biological applications. We show that specifically functionalized nanoparticles such as nanospheres, nanorods and hollow gold particles can migrate either on the cellular membrane or be endocytosed. A theoretical model is employed to discuss the potential use of these particles as tools for laser treatment of endothelial cells. Our studies open up new avenues towards manipulation of cells using gold nanoparticles and laser treatment.

Functional nanoparticles in cells

In this paper we present an overview of our recent studies regarding the interactions of functional nanoparticles with the human umbilical endothelial cells (HUVECs). Cellular uptake, cytotoxicity and laser hyperthermia of cells loaded with gold nanoparticles are discussed. Particles with different shape, size and charge are compared and evaluated to conclude at the most appropriate types for specific biomedical applications (i.e. drug delivery, laser hyperthermia).