Adolphe Merkle Institute

Fribourg, Switzerland

Adolphe Merkle Institute

Fribourg, Switzerland
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News Article | April 27, 2017
Site: www.cemag.us

Tiny, individual crystals on the underside of a Mexican butterfly’s wings give the insect a distinctive green color that allows it to hide from predators. Researchers at the University of Fribourg’s Adolphe Merkle Institute (AMI), the Karlsruhe Institute of Technology (KIT), the University of Erlangen-Nuremberg (FAU) in Germany, and Murdoch University in Western Australia, have shown for the first time how these crystals might grow. The scientists investigated the nanostructure on the wing scales of the green Hairstreak butterfly. What they found on each wing scale were structured nanocrystals that were surprisingly not interconnected. Rather they were a series of regularly spaced points where so-called gyroid photonic structures had grown. Gyroids are labyrinth-like three-dimensional structures first described by NASA scientist Allan Schoen. These structures, which are partially pigmented, are responsible for the butterfly’s green color. According to the researchers, the repetition of these nanostructures is similar to the wavelength of visible light which explains its peculiar optical property of producing a green color without any pigment. This was the first time this pattern was observed in butterflies, which are known for their particularly diverse wing scale structures. These structures are important to the insects for multiple functions such as signaling and water repellency. How the complex structures develop remains to this day largely unknown since it is impossible to observe on living specimens. The researchers were however able to infer that the structure they observed, using electron and x-ray microscopy, grew in a multistep process. In a first stage, an enveloping casing or mold develops. Then it is filled by a biopolymeric gyroid structure with a different chemical composition. This growth pattern contradicts previous theories. “Previous theories lacked the sampling and/or time resolution needed for the investigation,” explains Bodo Wilts, the lead AMI researcher on the project. “The unique structure found in these scales looks like it is still ‘growing’. Theories so far were based on single time points of the development. With our dataset, we are able to infer whether these are correct.” The results give insights into how butterfly wing cells develop, but could also provide inspiration for new nanoscale assembly techniques. The structures are not only precisely formed, but also developed under normal temperature and pressure conditions. “With optics and photovoltaics, we have taken inspiration from nature in terms of what structures we can copy and adapt. But we seem to neglect that we can also learn from the mechanisms nature employs to make these structures,” says Murdoch University’s Gerd Schroeder-Turk, one of the study’s co-authors. “Efficiencies and innovations are sure to be revealed if we can unpick these processes.” The results have been published in Science Advances, an open-access journal.


Schrettl S.,Ecole Polytechnique Federale de Lausanne | Contal E.,Ecole Polytechnique Federale de Lausanne | Hoheisel T.N.,Ecole Polytechnique Federale de Lausanne | Hoheisel T.N.,ETH Zurich | And 4 more authors.
Chemical Science | Year: 2015

Carbon-rich organic compounds containing a series of conjugated triple bonds (oligoynes) are relevant synthetic targets, but an improved access to oligoynes bearing functional groups would be desirable. Here, we report the straightforward synthesis of two series of oligoyne amphiphiles with glycoside or carboxylate polar head groups, investigate their self-assembly behavior in aqueous media, and their use as precursors for the formation of oligoyne rotaxanes with cyclodextrin hosts. To this end, we employed mono-, di-, or triacetylenic building blocks that gave access to the corresponding zinc acetylides in situ and allowed for the efficient elongation of the oligoyne segment in few synthetic steps via a Negishi coupling protocol. Moreover, we show that the obtained oligoyne derivatives can be deprotected to yield the corresponding amphiphiles. Depending on their head groups, the supramolecular self-assembly of these amphiphiles gave rise to different types of carbon-rich colloidal aggregates in aqueous media. Furthermore, their amphiphilicity was exploited for the preparation of novel oligoyne cyclodextrin rotaxanes using simple host-guest chemistry in water. This journal is © The Royal Society of Chemistry 2015.


Godel K.C.,University of Cambridge | Steiner U.,Adolphe Merkle Institute
Nanoscale | Year: 2016

We describe a new thin film deposition method for the growth of crystalline SbSI micro-needles via the conversion of Sb2S3 using SbI3 vapour, in a facile process that takes less than 15 minutes. These films were used to construct photodetectors in a sandwich-type architecture, which are superior to previously reported SbSI photodetectors. The devices exhibit a detectivity of D∗ = 109 Jones, a signal-to-noise ratio greater than SNR = 103 and a responsivity of R = 10-5 A W-1. In time response measurements, raise and fall times of less than 8 ms and 34 ms were determined. This manufacturing method greatly simplifies the creation of fast photodetectors. © 2016 The Royal Society of Chemistry.


Roose B.,Adolphe Merkle Institute | Pathak S.,University of Oxford | Steiner U.,Adolphe Merkle Institute
Chemical Society Reviews | Year: 2015

This review gives a detailed summary and evaluation of the use of TiO2 doping to improve the performance of dye sensitized solar cells. Doping has a major effect on the band structure and trap states of TiO2, which in turn affect important properties such as the conduction band energy, charge transport, recombination and collection. The defect states of TiO2 are highly dependent on the synthesis method and thus the effect of doping may vary for different synthesis techniques, making it difficult to compare the suitability of different dopants. High-throughput methods may be employed to achieve a rough prediction on the suitability of dopants for a specific synthesis method. It was however found that nearly every employed dopant can be used to increase device performance, indicating that the improvement is not so much caused by the dopant itself, as by the defects it eliminates from TiO2. Furthermore, with the field shifting from dye sensitized solar cells to perovskite solar cells, the role doping can play to further advance this emerging field is also discussed. © The Royal Society of Chemistry.


Pathak S.K.,University of Cambridge | Abate A.,University of Oxford | Ruckdeschel P.,University of Cambridge | Roose B.,University of Cambridge | And 12 more authors.
Advanced Functional Materials | Year: 2014

Reversible photo-induced performance deterioration is observed in mesoporous TiO2-containing devices in an inert environment. This phenomenon is correlated with the activation of deep trap sites due to astoichiometry of the metal oxide. Interestingly, in air, these defects can be passivated by oxygen adsorption. These results show that the doping of TiO2 with aluminium has a striking impact upon the density of sub-gap states and enhances the conductivity by orders of magnitude. Dye-sensitized and perovskite solar cells employing Al-doped TiO2 have increased device efficiencies and significantly enhanced operational device stability in inert atmospheres. This performance and stability enhancement is attributed to the substitutional incorporation of Al in the anatase lattice, "permanently" passivating electronic trap sites in the bulk and at the surface of the TiO2. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


The possibility of changing the molecular assembly of organic and organometallic materials through mechanical stimulation has enabled the design of a growing family of molecular materials with mechanoresponsive luminescence (MRL) characteristics. On page 1073, Y. Sagara, T. Kato, and co-workers review the state of the field and highlight emerging trends. The cover image shows the MRL behavior of a cyano-oligo(phenylenevinylene) dye. Image credit: Marc Karman, Adolphe Merkle Institute, University of Fribourg, Switzerland.


News Article | August 22, 2016
Site: www.nature.com

Hermann Staudinger was a pacifist, but this was one fight he was determined to win. In 1920, the German chemist proposed that polymers — a broad class of compounds that included rubber and cellulose — were made of long chains of identical small molecules linked by strong chemical bonds1. Most of his colleagues thought this was arrant nonsense, and argued that polymers were merely looser aggregations of small molecules. Staudinger refused to back down, sparking feuds that spanned a decade. Eventually, laboratory data proved that he was right. He won the 1953 Nobel Prize in Chemistry for his work, and synthetic polymers are now ubiquitous: last year, the world produced about 300 million tonnes of them. The molecular chains that Staudinger hypothesized have entered almost every aspect of modern life, from clothes, paint and packaging to drug delivery, 3D printing and self-healing materials. Polymer-based composites even make up half the weight of Boeing’s most recent passenger aeroplane, the 787 Dreamliner. So where will polymers go next? Some answers will come this week, when a once-per-decade workshop organized by the US National Science Foundation attempts to survey which new areas are emerging. “The general trend — still continuing — is the expansion of polymers into applications that have not been traditionally theirs,” says Tim Lodge, a polymer chemist at the University of Minnesota in Minneapolis and editor of the journal Macromolecules. That expansion has been driven by advances in every aspect of polymer science, he says. Researchers have developed new methods to synthesize and analyse molecules, improved theoretical models and created mimics of polymers found in nature. At the same time, says Lodge, attitudes to the science have changed. No longer do universities dismiss polymer science as too dirty, practical and industrial for academia. “Just about every chemistry department has someone doing polymer stuff now,” he says, and frontier work on polymers is increasingly interdisciplinary. It will need to be. Researchers have a growing toolbox of techniques with which to craft the chemical architecture of polymer strands, but they are often unable to predict whether the resulting compound will have the particular properties needed for, say, a membrane or a drug-delivery system. Meeting that challenge will demand a much deeper understanding of how the chemical structure of a polymer determines its physical properties, at every scale from nanometres to metres. Polymers are everywhere — and therein lies the problem. “Most polymers we use in everyday life are from petroleum-based products, and although they’re durable in use, they’re also durable in waste,” says Marc Hillmyer, director of the Center for Sustainable Polymers (CSP) at the University of Minnesota. An estimated 86% of all plastic packaging is used only once before it is discarded2, producing a stream of waste that persists in waterways and landfill, releases pollutants and harms wildlife. That is why the past decade has seen an explosion of interest in polymers that are made from renewable resources and biodegrade easily and harmlessly. Polymers based on natural starch are already on the market; so too is synthetic polylactide (PLA), which is made from lactide or lactic acid derived from biological sources, and which is found in products from tea bags to medical implants. But sustainable polymers still make up less than 10% of the total plastics market, says Hillmyer. One hurdle is that they cost too much. Another is that the monomer building blocks of natural polymers tend to contain more oxygen atoms than are found in the fossil hydrocarbons of petroleum. This affects the polymers’ properties — stiffening the materials, for example — which can make it difficult for them to directly replace cheap and flexible plastics such as polyethylene and poly­propylene. Turning natural polymers into exact molecular matches for conventional ones takes some sophisticated chemistry. One alternative approach is to beef up sustainable polymers such as PLA by blending them with conventional polymers. This route typically has downsides, such as rendering some plastics less transparent. But CSP researchers have got around that problem by adding just 5% by weight of a low-cost, petroleum-derived polymer that contains some sections that are hydrophobic — water-insoluble — and others that are hydrophilic, or water-soluble3. These additives cluster together to create spherical structures, which render PLA substantially tougher without reducing its transparency. Hillmyer’s team has also made4 a partially recyclable form of polyurethane foam, which is found in a host of products, including insulation, seat cushions and gaskets. The recipe for this polyurethane includes a low-cost poly­mer called poly(β-methyl-δ-valerolactone) (PMVL), based on monomers made by modified bacteria. Heating the foam to above 200 °C breaks down the polyurethane so that the monomers can be extracted and used again. It remains to be seen whether these sustainable polymers can be commercialized. “Often the biggest challenge is to do it at scale, which requires favourable economics,” says Hillmyer. He thinks the field needs to establish general design rules that predict how a monomer’s chemical structure affects the rate, temperature and yield of polymerization reactions, and how the resulting polymers will interact with other materials. His team has developed such guidelines for PMVL’s constituents5, and last year formed a spin-off company at the CSP called Valerian Materials to exploit these principles. Some researchers are pursuing another trick: rather than stringing together bioderived monomers, they are learning to use natural polymers directly. Cellulose, for example, consists of glucose molecules strung together into chains, which in turn line up to form strong fibres, or fibrils, that make up the stiff cell walls of plants. In many places, the cellulose chains form crystalline chunks that are up to 20 nanometres wide and hundreds of nano­metres long, and that can be chemically extracted from cellulose pulp. Proponents say that these crystals could be used for applications such as strengthening composites, forming insulating foams, delivering drugs and providing a scaffold for tissue repair6. Cellulose nanocrystals and longer nano­fibrils are now produced on a commercial scale, but the commercial applications do not yet go much beyond stiffening paper or thickening fluids. Christoph Weder, director of the Adolphe Merkle Institute for nanoscience at the University of Fribourg in Switzerland, says that it will take a lot more work to reduce costs and demonstrate unique advantages for sustainable polymers. “We really need a road map for biobased polymers,” he says. In a mixed-up world, polymers can restore some order. Polymer membranes already serve as molecular sieves for separating gases, de­salinating seawater and keeping molecules apart inside fuel cells. But they could have a much bigger impact in the future, says Lodge. “There are so many problems that could be solved by better membranes.” Separating mixtures with membranes takes a lot less energy than does distillation, in which a liquid is heated to evaporate its components at different temperatures. It also requires much less space than using scrubbers, devices in which pollutants are trapped by chemical reactions. Membranes made from polymers are not only cheap to make at large scale, but can cover large areas without acquiring structural defects that let the wrong molecules pass through. Gas-separation membranes are already used industrially to tease hydrogen and carbon dioxide from natural gas. But improved membranes could tackle harder tasks, such as distinguishing between the very similar hydrocarbons propane and propene. Tougher, chemically robust membranes could operate at higher temperatures to remove carbon dioxide from hot flue gases. Membrane chemist Benny Freeman of the University of Texas at Austin is hoping to improve the treatment of waste water from gas fracking operations, in which water is forced into rock to split it open and release natural gas. After use, the water is so dirty that standard filtration membranes quickly get clogged, so the water must be put under high pressure to push it through, and the membranes must be cleaned with chemicals that shorten their lifespan. But Freeman has found a way to sidestep that problem by giving the membranes a gossamer-thin coating of polydopamine, which mimics the waterproof glue used by mussels to cling onto rocks. Piloted at a fracking water-treatment facility near Fort Worth, Texas, the polydopamine coating halved the pressure needed to push water through the membrane, which could result in smaller, more efficient treatment systems7. The team has already used these membranes to build units for the US Navy, so that ships can purify oily bilge water before dumping it. In December 2015, the US presidential administration launched a ‘moonshot for water’ to boost water sustainability, and as part of that effort the US Department of Energy plans to establish a desalination-research hub in 2017. Polymer membranes will have a big role in that effort, says Freeman. “We’re slated to see a huge increase in efforts to expand the use of polymers in that space.” To design better desalination membranes, researchers will need to be able to predict how factors such as the distribution of charged chemical groups in a polymer affects its permeability to ions. Earlier this year, Freeman and his colleagues published8 what he believes is the first model to do just that, which could enable chemists to build particular properties into a membrane by tailoring its chemical substituents and cross-linking the molecules. “I’m on a mission to get people to ask these kinds of questions about structure–property relations, which could really guide synthesis,” he says. The ultimate separation membrane could be just one molecule thick. These 2D polymers are surfing the wave of enthusiasm for single-layer materials that followed the isolation of graphene just over a decade ago. The flat polymers are not just very thin films of ordinary, linear polymers. Instead, they have an intrinsically 2D chemical structure that looks like a fishing net, with a regular, repeating mesh full of molecule-size openings. They can also carry a wide variety of chemical decorations on their surfaces, so that each opening can be precisely engineered to allow certain molecules through and bar others. But creating 2D polymers is tough. If just one of the holes in the growing mesh closes up in the wrong way, the membrane could buckle into a 3D mess. Polymer chemist Dieter Schlüter of the Swiss Federal Institute of Technology in Zurich worked on this problem for more than a decade before achieving success in 2014. His approach relies on coaxing carefully designed monomers to form a crystal. A blast of blue light then triggers a chemical reaction between monomers in the same plane, creating a new crystal made up of stacked polymer layers. These can be peeled off to give individual 2D sheets just one monomer thick (see ‘Chemical peel’). Using the same approach, Schlüter and Benjamin King, head of the chemistry department at the University of Nevada, Reno, have independently produced different types of 2D polymer9, 10. Now collaborators, the two researchers hope that they will soon be able to make these sheets in kilogram batches, easily enough to distribute samples to research groups around the world. Schlüter admits that he has faced scepticism about whether 2D polymers will flourish. “But that’s healthy,” he says. “And I’m very stubborn — I will not give up, I’m convinced of the great potential this development has.” Widely used polymers such as polystyrene and polyethylene are spectacularly boring in one sense: they repeat the same monomer over and over again. Their one-note tune is especially monotonous when compared with the quadraphonic symphony of DNA, which encodes an entire genome with 4 monomers; or the baroque masterpiece of a protein, drawing from 23 amino acids to build a complex 3D structure. One of the most challenging frontiers of polymer research is to tailor synthetic polymers with the same precision, so that chemists can fine-tune the electronic and physical properties of their products. “It’s become very fashionable in the past five years,” says Jean-François Lutz, a macromolecular chemist at the University of Strasbourg in France. Sequence-controlled polymers would contain monomers in a predetermined order, forming strands of a very specific length. Last year, a team led by Jeremiah Johnson, a chemist at the Massachusetts Institute of Technology in Cambridge, showed11 that they could achieve that kind of control through iterative exponential growth — first uniting two different monomers to make a dimer, then connecting two dimers to make a tetramer, and so on. Modifying each monomer’s chemical side-chains between cycles adds complexity, and a semi-automated system can make the process less laborious12. Johnson is now studying how his sequence-controlled polymers might be used in drug delivery. A dozen drugs approved by the US Food and Drug Administration use a polymer called polyethylene glycol to shield them from the body’s immune system, improve their solubility or prolong their time in the body. Johnson says that a sequence-controlled polymer could provide a more predictable biological effect, because every strand would be the same length and shape, and its chemistry could be carefully designed to assist its drug cargo in the most useful way. Sequence-controlled polymers could also store data in a more compact and inexpensive form than can conventional semiconductor technology, with each monomer representing a single bit of information. Last year, Lutz demonstrated13 a key step towards that goal. He used two types of monomer to represent digital 1s or 0s, and a third to act as a spacer between them. The monomers contained chemical groups that allowed them to connect only to the growing polymer, rather than reacting with each other randomly. The string of 1s and 0s could be read by watching how the polymer broke apart inside a mass spectrometer. Earlier this month, Lutz showed that a library of different polymer strands could encode a 32-bit message14. That pales by comparison with the 1.6 gigabits that have been stored in artificial DNA molecules (see go.nature.com/2b2ve0u). But momentum is growing for polymer data storage. In April, the Intelligence Advanced Research Projects Activity (IARPA), a US agency that funds high-risk research for the intelligence community, drew representatives from the biotechnology, semiconductor and software industries to a workshop on the subject. “There’s a vibrant and growing community of researchers working on this,” says David Markowitz, a technical adviser at IARPA who helped to organize the workshop. But the approach still faces enormous technical challenges: current synthetic techniques are much too slow and expensive. The key to cracking the data-storage problem — and many other problems at the polymer frontier — will be to develop better ways to predict the properties of polymers and fine-tune their production. That will require a concerted effort. “We need to establish collaborations with physicists, materials scientists, theoretical chemists,” says Lutz. “We need to build a new field.”


Blood poisoning is still fatal in more than 50% of cases, but can be cured if treated at an early stage. The highest priority is therefore to act quickly. For this reason, doctors usually administer antibiotics even in the event of a suspicion of blood poisoning, without first ascertaining whether it is actually a bacterial sepsis, which in turn greatly increases the risk of resistance to antibiotics developing. It is therefore important to identify and develop a fast and effective therapy, if possible without the need to use antibiotics. An antibody for everything Empa researcher Inge Herrmann and her team are developing a solution in collaboration with modelling expert Marco Lattuada from the Adolphe Merkle Institute and doctors from the Harvard Medical School. The idea for the treatment is the magnetic purification of blood. The principle is, at least in theory, quite straightforward. Iron particles are coated with an antibody that detects and binds the harmful bacteria in the blood. As soon as the iron particles are attached to the bacteria, they are removed from the blood magnetically. However, there is (still) a small catch: So far, it has only been possible to coat the iron particles with antibodies that recognise one type of bacteria – but many different types of bacteria may be involved, depending on the species causing the blood poisoning. Using blood analysis, doctors must therefore first determine which bacteria is causing the poisoning before the appropriate antibodies can be used. "This blood analysis is time-consuming and time plays a vital role in the treatment of blood poisoning," explains Herrmann. This is also the reason for magnetic dialysis rarely having been used to date. But a team at the Harvard Medical School led by Gerald Pier has now developed an antibody that can bind almost all the bacteria that can trigger blood poisoning - so if there is a suspicion of sepsis, the magnetic treatment could be started immediately, regardless of which pathogen is in the blood. This "allrounder" antibody to succeed in isolating pathogenic bacteria - similar to using dialysis. How harmful are the iron particles? The method is not yet sufficiently mature to be used on patients. In a next step, Herrmann wants to carry out tests with various other germs and find out whether the Harvard antibody can actually bind additional bacteria to itself. The nature of the iron particles is also not to be underestimated. It may be the case that some particles remain in the blood after the magnetic extraction has been carried out. The requirements for these carriers are thus clear: they must not harm the human body. But Herrmann's team already has a solution ready in this regard. The tiny iron particles are assembled into larger clusters and are thus more responsive to the magnet. In addition, the researchers have been able to demonstrate, in an in vitro simulation, that the iron particles are broken down completely after only five days. Further experiments still to come In the future, it should therefore no longer be strictly necessary to administer antibiotics as soon as there is a suspicion of sepsis. Blood will be taken from the patient for analysis, and the patient connected to a dialysis machine to cleanse the blood, no matter what bacteria are in it. As soon as the doctors have the detailed blood values, an antibiotic therapy tailored to the pathogen can be introduced, if necessary. This idea is currently just a future ambition, as there are still numerous issues that need to be clarified. Firstly, it is imperative that this method is used in the initial stage of sepsis, when the damage has not yet spread from the blood to the organs or bodily functions, and there is also the issue of how well this treatment will work in unstable patients or patients with pre-existing conditions. But Herrmann and her team are optimistic - and also a step closer to achieving a new and more gentle treatment for sepsis. Explore further: Personalised prescription tool could help to combat antibiotic resistance More information: M. Lattuada et al. Theranostic body fluid cleansing: rationally designed magnetic particles enable capturing and detection of bacterial pathogens, J. Mater. Chem. B (2016). DOI: 10.1039/c6tb01272h


News Article | December 7, 2016
Site: www.cemag.us

Blood poisoning is still fatal in more than 50 percent of cases, but can be cured if treated at an early stage. The highest priority is therefore to act quickly. For this reason, doctors usually administer antibiotics even in the event of a suspicion of blood poisoning, without first ascertaining whether it is actually a bacterial sepsis, which in turn greatly increases the risk of resistance to antibiotics developing. It is therefore important to identify and develop a fast and effective therapy, if possible without the need to use antibiotics. Empa researcher Inge Herrmann and her team are developing a solution in collaboration with modeling expert Marco Lattuada from the Adolphe Merkle Institute and doctors from the Harvard Medical School. The idea for the treatment is the magnetic purification of blood. The principle is, at least in theory, quite straightforward. Iron particles are coated with an antibody that detects and binds the harmful bacteria in the blood. As soon as the iron particles are attached to the bacteria, they are removed from the blood magnetically. However, there is (still) a small catch: So far, it has only been possible to coat the iron particles with antibodies that recognize one type of bacteria — but many different types of bacteria may be involved, depending on the species causing the blood poisoning. Using blood analysis, doctors must therefore first determine which bacteria is causing the poisoning before the appropriate antibodies can be used. "This blood analysis is time-consuming and time plays a vital role in the treatment of blood poisoning," explains Herrmann. This is also the reason for magnetic dialysis rarely having been used to date. But a team at the Harvard Medical School led by Gerald Pier has now developed an antibody that can bind almost all the bacteria that can trigger blood poisoning — so if there is a suspicion of sepsis, the magnetic treatment could be started immediately, regardless of which pathogen is in the blood. This "allrounder" antibody to succeed in isolating pathogenic bacteria — similar to using dialysis. The method is not yet sufficiently mature to be used on patients. In a next step, Herrmann wants to carry out tests with various other germs and find out whether the Harvard antibody can actually bind additional bacteria to itself. The nature of the iron particles is also not to be underestimated. It may be the case that some particles remain in the blood after the magnetic extraction has been carried out. The requirements for these carriers are thus clear: they must not harm the human body. But Herrmann's team already has a solution ready in this regard. The tiny iron particles are assembled into larger clusters and are thus more responsive to the magnet. In addition, the researchers have been able to demonstrate, in an in vitro simulation, that the iron particles are broken down completely after only five days. In the future, it should therefore no longer be strictly necessary to administer antibiotics as soon as there is a suspicion of sepsis. Blood will be taken from the patient for analysis, and the patient connected to a dialysis machine to cleanse the blood, no matter what bacteria are in it. As soon as the doctors have the detailed blood values, an antibiotic therapy tailored to the pathogen can be introduced, if necessary. This idea is currently just a future ambition, as there are still numerous issues that need to be clarified. Firstly, it is imperative that this method is used in the initial stage of sepsis, when the damage has not yet spread from the blood to the organs or bodily functions, and there is also the issue of how well this treatment will work in unstable patients or patients with pre-existing conditions. But Herrmann and her team are optimistic — and also a step closer to achieving a new and more gentle treatment for sepsis.


News Article | December 7, 2016
Site: www.eurekalert.org

Blood poisoning is still fatal in more than 50% of cases, but can be cured if treated at an early stage. The highest priority is therefore to act quickly. For this reason, doctors usually administer antibiotics even in the event of a suspicion of blood poisoning, without first ascertaining whether it is actually a bacterial sepsis, which in turn greatly increases the risk of resistance to antibiotics developing. It is therefore important to identify and develop a fast and effective therapy, if possible without the need to use antibiotics. An antibody for everything Empa researcher Inge Herrmann and her team are developing a solution in collaboration with modelling expert Marco Lattuada from the Adolphe Merkle Institute and doctors from the Harvard Medical School. The idea for the treatment is the magnetic purification of blood. The principle is, at least in theory, quite straightforward. Iron particles are coated with an antibody that detects and binds the harmful bacteria in the blood. As soon as the iron particles are attached to the bacteria, they are removed from the blood magnetically. However, there is (still) a small catch: So far, it has only been possible to coat the iron particles with antibodies that recognise one type of bacteria - but many different types of bacteria may be involved, depending on the species causing the blood poisoning. Using blood analysis, doctors must therefore first determine which bacteria is causing the poisoning before the appropriate antibodies can be used. "This blood analysis is time-consuming and time plays a vital role in the treatment of blood poisoning," explains Herrmann. This is also the reason for magnetic dialysis rarely having been used to date. But a team at the Harvard Medical School led by Gerald Pier has now developed an antibody that can bind almost all the bacteria that can trigger blood poisoning - so if there is a suspicion of sepsis, the magnetic treatment could be started immediately, regardless of which pathogen is in the blood. This "allrounder" antibody to succeed in isolating pathogenic bacteria - similar to using dialysis. How harmful are the iron particles? The method is not yet sufficiently mature to be used on patients. In a next step, Herrmann wants to carry out tests with various other germs and find out whether the Harvard antibody can actually bind additional bacteria to itself. The nature of the iron particles is also not to be underestimated. It may be the case that some particles remain in the blood after the magnetic extraction has been carried out. The requirements for these carriers are thus clear: they must not harm the human body. But Herrmann's team already has a solution ready in this regard. The tiny iron particles are assembled into larger clusters and are thus more responsive to the magnet. In addition, the researchers have been able to demonstrate, in an in vitro simulation, that the iron particles are broken down completely after only five days. Further experiments still to come In the future, it should therefore no longer be strictly necessary to administer antibiotics as soon as there is a suspicion of sepsis. Blood will be taken from the patient for analysis, and the patient connected to a dialysis machine to cleanse the blood, no matter what bacteria are in it. As soon as the doctors have the detailed blood values, an antibiotic therapy tailored to the pathogen can be introduced, if necessary. This idea is currently just a future ambition, as there are still numerous issues that need to be clarified. Firstly, it is imperative that this method is used in the initial stage of sepsis, when the damage has not yet spread from the blood to the organs or bodily functions, and there is also the issue of how well this treatment will work in unstable patients or patients with pre-existing conditions. But Herrmann and her team are optimistic - and also a step closer to achieving a new and more gentle treatment for sepsis.

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