Biofilm and Materials Science
Some of us who are hospitalized are feeling worse rather than better. On average, seven percent of all patients in industrial countries are affected by "nosocomial" infections. In intensive care units, the risk increases even more.
Characteristics of Alcian-blue Dye Adsorption of Natural Biofilm Matrix
This can result in serious illnesses and life-threatening blood poisoning. If patients are treated with invasive medical measures, hospital germs have a particularly easy time of it: If tubes are inserted into the body, for instance to ventilate it, supply it with fluids or drain urine, the infectious agents quickly gain a hold. It is still unclear how these infections can be prevented. A team of Empa scientists and physicians from the Cantonal Hospital of St. Gallen is currently working on a project aimed at reducing the risk of hospital infections. The focus lies on the analysis of biofilms, accumulations of germs on surfaces that spread in, say, urinary catheters.
However, if materials are to be designed to prevent the formation of biofilms, it must first be established how germ growth actually occurs on surfaces. It is simply not possible to develop suitable protective measures against the unknown. And this is where medicine has literally stuck in the dark — because it was largely unknown what exactly grows inside a catheter. Empa researcher Qun Ren is on the hunt for the secrets inside the polymer stents. Together with the St. The use of a catheter or stent in the ureter is a common procedure, for example in the treatment of kidney stones.
This was also seen with the patients she examined: After a comparatively short period of about 3 weeks in the body, not only calcium crystals from urine were deposited in the tubes; the researcher also found bacterial accumulations in the samples. And it is precisely with these biofilms that scientists hold what is probably the world's most successful living being in their hands: Bacterial accumulations embedded in a self-produced slimy matrix that behave like a single organism.
And they have been around long before us: Biofilms can already be found in the oldest known fossils of Earth's history. Given their amazing survival strategies it is hardly surprising that they have since persisted and thrived under the worst of conditions such as in urinary catheters.
Thanks to a humid layer of biopolymers, the bacteria living together in biofilms are protected, mobile and connected to each other. They happily exchange useful genetic material, communicate via chemical signals and report to the surface when the deeper layers of the "flat share" suffer from hunger. Antibiotics and disinfectants hardly penetrate the film, and if necessary they send a group of pioneers to a new location and found further colonies, pretty much like a metastatic tumor.
What is successful in nature can end badly in hospitals.
The aim is, therefore, to develop new materials, for example for stents that reduce the risk of infection. Some of the microorganisms use the same trick as geckos, which can cling to a glass pane upside down: They use van der Waals forces, interactions between their own molecules and those of the surface that is supposed to offer them a new home.
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Other examples coat the surfaces of tubes and stents with a suitable coating, which helps them to settle on the surface. The prerequisite for workable materials and coatings that resist germs is the seamless transfer of research results "from bench to bedside". A material can only prove itself if the analyses in the laboratory are as realistic as possible.
Empa researchers have, therefore, developed a multi-part lab model, the conditions of which are as close as possible to those in the hospital. Potential novel catheter mterials are rinsed with liquids in a bioreactor, as in the case of a real urinary stent inside the body. All isolated microorganisms are examined using confocal microscopy, bacterial culture and genetic analysis. At the same time, the material's surface that is covered with calcium crystals is characterized using X-ray analysis. The samples from the Cantonal Hospital in St.
Gallen have now been used to show exactly what happens in the body with catheters made of conventional materials. Since all of these were patients with no signs of infection before the catheter was inserted and who carried the stent for only a short time in their bodies, all isolated biofilms were mild, as could be expected. However, it became clear that certain types of bacteria like to occur together. For example, some patients had harmful enterobacteria in their samples, while others had species of microorganisms such as lactic acid bacteria, which are thought to have a protective effect.
The researchers will now investigate how these various "urotypes" are associated with the risk of hospital infection. The desired biocatalytic transformation occurs due to the enzymes that are irreversibly immobilized in the extracellular matrix of these biofilms. The enhanced mass transfer rates and surface area in these biofilms results in increased enzymatic activities.
Such biofilms could also be engineered to produce scaffolded chemical pathways, in which successive chemical reactions are catalyzed by individual stacked layers of bacteria, leading to production of a single product or a series of products via a relay of reactions. As one example, the printed bacteria could be genetically manipulated to perform complex logic gate functions, 13 such that the output of one layer could serve as the input to the adjacent layer. Alternatively, templated assembly of nanoparticles on engineered biofilms could also be used to catalyze multistep hybrid reaction systems.
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Nonengineered beneficial bacterial biofilms could be 3D-printed as an antifouling coating on building or marine vessel surfaces. These living functional bacteria would use up the oxygen on the surface and in turn could produce compounds that are anticorrosive, thereby preventing corrosion and biofouling. Similarly, probiotic biofilms could be 3D-printed onto various biomedical implant surfaces to prevent device-associated infections caused by pathogenic bacteria.
However, the real-time application of such approaches is far from the current realizations and demands further research. Synthetic biofilms displaying selected catabolic enzymes, heavy metal binding proteins, inorganic nanoparticles, or REE-binding domains could be 3D-printed onto filters or onto pipes and reactors in treatment plants to carry out the desired degradation or abstraction activities as the contaminating streams flow past.
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Analytical techniques such as HPLC—MS or ICP-MS could be used to quantify the amount of chemicals absorbed onto the biofilm matrix components, and the bound residues could then be desorbed with simple acidic or alkaline washes. Metal-binding domains could be additionally added to these synthetic biofilms to facilitate their strong surface attachment such that they could resist detachment forces and withstand multiple sorption—desorption cycles. With appropriate tuning of the bioink porosity, such 3D-printed biofilms could be recyclable and reusable with minimum loss of efficiency.
Incorporation of feedback-regulated genetic circuits could be used in situations involving continuous detoxification such that synthetic biofilms are produced only when the specific target chemical is sensed, thereby improving the overall absorption efficiencies. Following appropriate exposure times, imaging techniques and -omics approaches transcriptomics, proteomics, or metabolomics could then be used on both the bacterial and host samples to decipher their communication and community behavior. Studying these interactions would greatly help in infectious disease management and discovery of new antibiofilm drugs.
In natural biofilms, factors like the density of the bacteria and the extracellular matrix components, the distribution of nutrients and signaling molecules, the locations of water channels, and the distribution of molecular oxygen are dynamic variables. The consequences of these variables on the emergent biological metabolic heterogeneity and antibiotic resistance and mechanical cohesiveness, viscoelasticity, resistance to hydrodynamic shear and desiccation phenotypes in biofilms are not well characterized. These studies could lead to development of an engineered and reproducible biofilm model system that mimics the robustness of natural biofilms while maintaining their structure—function relationships over time.
Such model biofilms could then be used for practical applications such as testing potential antibiofilm treatments, evaluating the adequacy of mathematical models of biofilms, etc. Conclusions and Outlook. However, factors such as reusability, scalability, and potential environmental impacts must be closely investigated for individual applications.
For instance, the release of genetically modified bacteria from 3D-printed devices could pose a risk to the environment or to human health, and bacterial contamination must be prevented. For societal applications such as drinking water plants, contamination risks could be eliminated by 3D printing cell-free functional extracellular matrix components that were isolated from biofilms by vacuum filtration. Such components will have longer stability and reusability compared to living bacteria and would not need constant maintenance. An interesting potential application could involve 3D printing multifunctional biofilms that can be used in dynamic settings.
Such biofilms could be created by 3D printing either a bioink containing a cocktail of multiple genetically engineered bacteria possessing genetic fusions of different functional proteins and biofilm proteins, or layers of such bacteria one over the other. In either case, cross-seeding of engineered biofilm proteins could occur, leading to a combination of different functionalities in the resultant multifunctional biofilms.
Another possible application of 3D-printed biofilms is the creation of responsive materials that could alter their chemical or mechanical properties based on specific environmental cues and triggers. The adaptive nature of such materials would impart them with enhanced lifetimes and continuous functionalities. Overall, the effectiveness, stability, and versatility of 3D bioprinting approaches in combination with the distinct characteristics of bacterial biofilms offer an ideal platform for the fabrication of biofilm-derived products in materials processing and manufacturing.
Author Contributions S. The authors declare no competing financial interest. ACS Synth. American Chemical Society. Sustainable and personally tailored materials prodn. Living organisms can produce and pattern an extraordinarily wide range of different mols. These natural systems offer an abundant source of inspiration for the development of new environmentally friendly materials prodn.yoku-nemureru.com/wp-content/spyware/1655-how-to-put.php
Biofilm and Materials Science | Hideyuki Kanematsu | Springer
In this paper, the authors describe the first steps toward the 3-dimensional printing of bacterial cultures for materials prodn. This methodol. For this purpose, a com. Printing temp. The combination of 3D printing technol.
Novel anti-biofilm nano coating developed
Schmieden, Dominik T. Biofilms can grow on virtually any surface available, with impacts ranging from endangering the lives of patients to degrading unwanted water contaminants. Biofilm research is challenging due to the high degree of biofilm heterogeneity. A method for the prodn. Here, we present such a method, combining 3D printing with genetic engineering. We prototyped a low-cost 3D printer that prints bioink, a suspension of bacteria in a soln. We 3D-printed Escherichia coli in different shapes and in discrete layers, after which the cells survived in the printing matrix for at least 1 wk.
When printed bacteria were induced to form curli fibers, the major proteinaceous extracellular component of E. This work is the first demonstration of patterned, biofilm-inspired living materials that are produced by genetic control over curli formation in combination with spatial control by 3D printing. These materials could be used as living, functional materials in applications such as water filtration, metal ion sequestration, or civil engineering, and potentially as standardizable models for certain curli-contg.
Journal of internal medicine , 4 , ISSN:. Although biofilms have been observed early in the history of microbial research, their impact has only recently been fully recognized. The associated chronic infections such as wound infections, dental caries and periodontitis significantly enhance morbidity, affect quality of life and can aid development of follow-up diseases such as cancer. Biofilm infections remain challenging to treat and antibiotic monotherapy is often insufficient, although some rediscovered traditional compounds have shown surprising efficiency.