The nanogels — only 200 nanometers in diameter — possess many unique properties that make them ideal drug-delivery tools, according to Daniel Siegwart, a graduate student in University Professor Krzysztof Matyjaszewski’s laboratory at Carnegie Mellon. Siegwart will present his research Monday, Aug. 20 at the 234th national meeting of the American Chemical Society in Boston.
ATRP, a controlled living radical polymerization process, allows chemists to precisely regulate the composition and architecture of the polymers they are creating. Siegwart and colleagues used ATRP in inverse miniemulsion to make nanogels with a uniform network of cross-linked polymer chains within a spherical nanoparticle.
“A uniform mesh size within the nanogels should improve the controlled release of the encapsulated drugs,” said Siegwart. “The major advance of this system is that ATRP allows one to prepare nanogels that are uniform in diameter. The size of the particles can be tuned, and we are currently investigating how nanogels of different sizes enter cells. The results may allow us to better understand the mechanism of endocytosis and to target specific tissues, such as cancer cells that have a more permeable membrane.”
In their most recent advance, the Carnegie Mellon team incorporated the model carbohydrate drug rhodamine isothiocyanate-labeled dextran into the nanogel’s uniform mesh core. When the nanogels degraded, the model carbohydrate drug was released over time. The experiments were carried out with Jung Kwon Oh, a former postdoctoral associate in the Matyjaszewski lab who developed ATRP in inverse miniemulsion.
The new nanogels, which are nontoxic and biodegradable, can also accommodate molecules on their surfaces. During nanogel synthesis, the ATRP process allows scientists to incorporate “targeting groups” on the nanogel surface that can interact with specific receptors, such as those on the surface of a cancer cell. In addition, the nanogels can escape the notice of the body’s immune system, thus prolonging circulation time within the bloodstream.
“The basic composition of the nanogels is based on an analogue of poly(ethylene oxide), a well-established biocompatible polymer that can enhance blood circulation time and prevent clearance by the reticuloendothelial system, the part of the immune system that engulfs and removes foreign objects from the body,” said Siegwart.
In a recent article published in the Journal of the American Chemical Society, the Carnegie Mellon team demonstrated that its novel nanogels could be used to encapsulate doxorubicin, an anticancer drug. When the scientists mixed the doxorubicin-loaded nanogels with HeLa cancer cells in the laboratory, the doxorubicin was released, penetrating the cancer cells and significantly inhibiting their growth. They carried out this work in collaboration with Jeffrey Hollinger, professor of biomedical engineering and biological sciences and director of the Bone Tissue Engineering Center at Carnegie Mellon.
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy