Researchers at the University of California, Berkeley (USA) have now developed a new strategy for the formation of hybrid materials from synthetic polymers and proteins. They have thus been able to fuse the specific biological functions of proteins with the advantageous bulk and processing properties of plastics. Polymer-protein hybrid materials may be of use in the manufacture of sensors, nanomachine parts, or drug-delivery systems.
As Aaron P. Esser-Kahn and Matthew B. Francis report in the journal Angewandte Chemie, they have successfully synthesized a green-fluorescing biodegradable gel that responds to changes in pH value and temperature.
Previous processes for the production of hybrid materials depended on very specific coupling techniques that could not be used for some protein side-chains. In contrast, the new method developed by the Berkeley researchers is broadly applicable because in principle it is suitable for any protein. The coupling occurs at both ends of the protein chain—and these are the same for all proteins: one amino acid group and one carboxylic acid group.
Initially, two parallel but mutually independent (orthogonal) reactions are used to activate the two ends of the chain. These are then attached to special chemical “anchor points” on the polymer. The proteins thus cross-link the individual polymer chains into a three-dimensional network, forming what is known as a hydrogel. A hydrogel is a solid, gelatinous mass consisting of water incorporated in a polymer network. A well-known example of a hydrogel is the soft contact lens.
Francis and Esser-Kahn chose to use a protein that fluoresces green to cross-link their polymer chains. Because the protein maintains its normal folding pattern even after attachment to the polymer, the fluorescence is also maintained: The entire gel fluoresces green.
This hybrid material has a special trait: the cross-linking of the polymer chains is achieved exclusively by means of the proteins. Because proteins can be attacked by proteases, enzymes that disintegrate proteins, these gels are biodegradable. The green fluorescence of the protein is pH-dependent. The gel correspondingly also reacts to changes in pH. It only fluoresces in the basic range; in a lightly acidic medium, the gel no longer fluoresces. Raising the temperature also elicits a response from the gel. The protein denatures at about 70 °C, which quenches the fluorescence and causes the gel to shrink.
Author: Matthew B. Francis, University of California, Berkeley (USA), http://chem.berkeley.edu/people/faculty/francis/francis.html
Title: Protein-Cross-Linked Polymeric Materials through Site-Selective Bioconjugation
Angewandte Chemie International Edition 2008, 47, No. 20, 3751–3754, doi: 10.1002/anie.200705564
Matthew B. Francis | Angewandte Chemie
Make way for the mini flying machines
21.03.2018 | American Chemical Society
New 4-D printer could reshape the world we live in
21.03.2018 | American Chemical Society
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
21.03.2018 | Physics and Astronomy
21.03.2018 | Materials Sciences
21.03.2018 | Life Sciences