8 research outputs found
Periodic Operation of a Dynamic DNA Origami Structure Utilizing the HydrophilicâHydrophobic PhaseâTransition of StimulusâSensitive Polypeptides
Dynamic DNA nanodevices are designed to perform structureâencoded motion actuated by a variety of different physicochemical stimuli. In this context, hybrid devices utilizing other components than DNA have the potential to considerably expand the library of functionalities. Here, the reversible reconfiguration of a DNA origami structure using the stimulus sensitivity of elastinâlike polypeptides is reported. To this end, a rectangular sheet made using the DNA origami technique is functionalized with these peptides and by applying changes in salt concentration the hydrophilicâhydrophobic phase transition of these peptides actuate the folding of the structure. The onâdemand and reversible switching of the rectangle is driven by externally imposed temperature oscillations and appears at specific transition temperatures. Using transmission electron microscopy, it is shown that the structure exhibits distinct conformational states with different occupation probabilities, which are dependent on structureâintrinsic parameters such as the local number and the arrangement of the peptides on the rectangle. It is also shown through ensemble fluorescence resonance energy transfer spectroscopy that the transition temperature and thus the thermodynamics of the rectangleâpeptide system depends on the stimuli salt concentration and temperature, as well as on the intrinsic parameters
Growth of Giant Peptide Vesicles Driven by Compartmentalized TranscriptionâTranslation Activity
Practical Assessment of an Interdisciplinary Bacteriophage Delivery Pipeline for Personalized Therapy of Gram-Negative Bacterial Infections
Despite numerous advances in personalized phage therapy, smooth logistics are challenging, particularly for multidrug-resistant Gram-negative bacterial infections requiring high numbers of specific lytic phages. We conducted this study to pave the way for efficient logistics for critically ill patients by (1) closely examining and improving a current pipeline under realistic conditions, (2) offering guidelines for each step, leading to safe and high-quality phage supplies, and (3) providing a tool to evaluate the pipeline’s efficiency. Due to varying stipulations for quality and safety in different countries, we focused the pipeline on all steps up to a required phage product by a cell-free extract system. The first of three study runs included patients with respiratory bacterial infections from four intensive care units, and it revealed a cumulative time of up to 23 days. Ultimately, adjustment of specific set points of the vulnerable components of the pipeline, phage isolation, and titration increased the pipeline’s efficiency by 15% and decreased the maximum required time to 13 days. We present a site-independent practical approach to establish and optimize pipelines for personalized phage delivery, the co-organization of pipeline components between different institutions, non-binding guidelines for every step, and an efficiency check for phage laboratories
Periodic Operation of a Dynamic DNA Origami Structure Utilizing the HydrophilicâHydrophobic PhaseâTransition of StimulusâSensitive Polypeptides
Dynamic DNA nanodevices are designed to perform structureâencoded motion actuated by a variety of different physicochemical stimuli. In this context, hybrid devices utilizing other components than DNA have the potential to considerably expand the library of functionalities. Here, the reversible reconfiguration of a DNA origami structure using the stimulus sensitivity of elastinâlike polypeptides is reported. To this end, a rectangular sheet made using the DNA origami technique is functionalized with these peptides and by applying changes in salt concentration the hydrophilicâhydrophobic phase transition of these peptides actuate the folding of the structure. The onâdemand and reversible switching of the rectangle is driven by externally imposed temperature oscillations and appears at specific transition temperatures. Using transmission electron microscopy, it is shown that the structure exhibits distinct conformational states with different occupation probabilities, which are dependent on structureâintrinsic parameters such as the local number and the arrangement of the peptides on the rectangle. It is also shown through ensemble fluorescence resonance energy transfer spectroscopy that the transition temperature and thus the thermodynamics of the rectangleâpeptide system depends on the stimuli salt concentration and temperature, as well as on the intrinsic parameters
Self-Assembled Active Plasmonic Waveguide with a Peptide-Based Thermomechanical Switch
Nanoscale plasmonic
waveguides composed of metallic nanoparticles
are capable of guiding electromagnetic energy below the optical diffraction
limit. Signal feed-in and readout typically require the utilization
of electronic effects or near-field optical techniques, whereas for
their fabrication mainly lithographic methods are employed. Here we
developed a switchable plasmonic waveguide assembled from gold nanoparticles
(AuNPs) on a DNA origami structure that facilitates a simple spectroscopic
excitation and readout. The waveguide is specifically excited at one
end by a fluorescent dye, and energy transfer is detected at the other
end <i>via</i> the fluorescence of a second dye. The transfer
distance is beyond the multicolor FRET range and below the AbbeÌ
limit. The transmittance of the waveguide can also be reversibly switched
by changing the position of a AuNP within the waveguide, which is
tethered to the origami platform by a thermoresponsive peptide. High-yield
fabrication of the plasmonic waveguides in bulk was achieved using
silica particles as solid supports. Our findings enable bulk solution
applications for plasmonic waveguides as light-focusing and light-polarizing
elements below the diffraction limit
Formation of vesicular structures from fatty acids formed under simulated volcanic hydrothermal conditions
Abstract Microscopic compartmentalization is beneficial in synthetic chemistry and indispensable for the evolution of life to separate a reactive âinsideâ from a hydrolyzing âoutsideâ. Here, we show compartmentalization in aqueous solution containing mixtures of fatty acids up to 19 carbon atoms which were synthesized by one-pot reactions of acetylene and carbon monoxide in contact with nickel sulfide at 105 °C, reaction requirements which are compatible to Hadean Early Earth conditions. Based on confocal, dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements, vesicle-like structures with diameters of 10â150 nm are formed after solvent extraction and resolubilisation. Moreover fluorescent dye was encapsulated into the structures proving their vesicular properties. This self-assembly could also have occurred on Early Earth as a crucial step in establishing simple membranes of proto-cells as a prerequisite in the evolution of metabolism and life
Phage Therapy in GermanyâUpdate 2023
Bacteriophage therapy holds promise in addressing the antibiotic-resistance crisis, globally and in Germany. Here, we provide an overview of the current situation (2023) of applied phage therapy and supporting research in Germany. The authors, an interdisciplinary group working on patient-focused bacteriophage research, addressed phage production, phage banks, susceptibility testing, clinical application, ongoing translational research, the regulatory situation, and the network structure in Germany. They identified critical shortcomings including the lack of clinical trials, a paucity of appropriate regulation and a shortage of phages for clinical use. Phage therapy is currently being applied to a limited number of patients as individual treatment trials. There is presently only one site in Germany for large-scale good-manufacturing-practice (GMP) phage production, and one clinic carrying out permission-free production of medicinal products. Several phage banks exist, but due to varying institutional policies, exchange among them is limited. The number of phage research projects has remarkably increased in recent years, some of which are part of structured networks. There is a demand for the expansion of production capacities with defined quality standards, a structured registry of all treated patients and clear therapeutic guidelines. Furthermore, the medical field is still poorly informed about phage therapy. The current status of non-approval, however, may also be regarded as advantageous, as insufficiently restricted use of phage therapy without adequate scientific evidence for effectiveness and safety must be prevented. In close coordination with the regulatory authorities, it seems sensible to first allow some centers to treat patients following the Belgian model. There is an urgent need for targeted networking and funding, particularly of translational research, to help advance the clinical application of phages