Bending Dynamics Research Articles

Transcription, torsional stress and the bending dynamics of DNA

In this research, we found that the local opening of base pairs induces the formation of kinks which facilitates the bending of double helix. The conformational properties of DNA can be mapped onto the Heisenberg spin system and denaturation occurs through quantum phase transition (QPT) induced by a quench when the temperature effect is incorporated through the quench time. The nonequilibrium effect in QPT introduced through the quench generate defects like kinks end antikinks, the density of which depends on the quench time and hence on temperature. It is here argued that when we transcribe this result in the rod –like-chain (RLC) model of DNA, these defects correspond to bends. The dynamical formation of these bends during local denaturation associated with transcription hinders free rotation of the transcribed DNA and helps the torsional stress to propagate down the DNA. This explains the observed large torsional stress near the point of transcription. We have estimated the bend length which is found to be in good agreement with experiments.

Linking the Dynamics of Clathrin-Mediated Endocytosis with Membrane Shape Changes in Living Cells with Nanometer Axial Resolution

Clathrin-mediated endocytosis (CME) is essential for cellular homeostasis. Thus, a precise understanding of the biophysical properties of vesicle formation and internalization is necessary. Due to fast dynamics, heterogeneity, and the number of proteins involved in CME, our current knowledge is limited and biased. While fluorescence microscopy provides information about the spatio-temporal dynamics of proteins, it lacks evidence for membrane bending. In contrast, electron microscopy shows membrane curvature, but it lacks dynamic insight. Here, by using Simultaneous Two-wavelength Axial Ratiometry (STAR), we link clathrin dynamics with membrane shape changes. STAR is a TIRF based microscopy technique we developed that takes advantage of the variance in penetration depth generated by different laser wavelengths. By imaging proteins tagged with the EGFP-iRFP fusion (STAR probe), we can generate the ratio of fluorescent intensity and convert it into axial information. The initial transition of plasma membrane from flat to curved and its correlation with clathrin arrival, during endocytosis, remains unclear. We report three different bending dynamics in Cos-7 cells transfected with clathrin light chain STAR probe. Most often clathrin accumulates along with curvature generation, or curvature starts forming shortly before clathrin arrival. Rarely, clathrin first assembles as a flat lattice prior to vesicle formation. Surprisingly, a quarter of de novo clathrin assemblies does not induce curvature. We hypothesize that the flat lattices might be caused by the absence of activated receptors, curvature sensing/inducing proteins, or vesicle maturation markers. To test this and to further describe the difference in initial curvature generation, we are developing a three-color STAR approach to integrate endocytic components with membrane shape changes. In doing so, we hope to unify the physical process of vesicle formation in clathrin-mediated endocytosis with its dynamics.

Formation of mathematical models of stationary dynamics of structures which include thin elastic plates with distributed inertial parameters

This paper is devoted to the problems of modeling stationary oscillatory processes in elastic systems that contain thin-walled plates. The described method allows us to include the mathematical formalization of thin-walled plates in oscillatory models of elastic structures with irregular boundaries of computational areas and heterogeneous boundary conditions. The formation of dynamic models of this kind is based on the use of discretization methods, in particular, finite element methods that allows approximating the initial models with distributed inertial and rigid parameters — discrete ones with concentration of parameters at certain points — nodes of a dynamic system. Obviously, such approximations are accompanied by errors, the estimation of which is extremely difficult to perform under the conditions of the mentioned heterogeneities and irregularities even in the interval variants. In the present work, the construction of elements of bending stationary vibrations of thin-walled plates under monoharmonic effects is proposed. Possessing all the properties of a finite element, the proposed element contains the values of the distributed masses as parameters. In contrast to the use of discretized parameters obtained by using the classical finite element, the proposed method eliminates discretization procedures and thus, eliminates the process of forming mathematical models from additional errors associated with discretization procedures. This element of mathematical modeling of the dynamics of bending is called a harmonic element (HaE). The proposed method is based on the development of dynamic compliance methods, previously used to simulate oscillations of beam systems with distributed parameters. The developed mathematical models of stationary oscillations of thin elastic plates with distributed inertial parameters make it possible to include them in discrete-continuous models containing infinite-dimensional flexural elements (plates and beams), material points, solids and concentrated elasticities. Thus, dynamic models of structures subjected to harmonic effects are represented by a set of harmonic elements (HaE), which allow harmonic matching of heterogeneous elements under different boundary conditions.

Analytically Embedding Differential Equation Constraints into Least Squares Support Vector Machines Using the Theory of Functional Connections.

Differential equations (DEs) are used as numerical models to describe physical phenomena throughout the field of engineering and science, including heat and fluid flow, structural bending, and systems dynamics. While there are many other techniques for finding approximate solutions to these equations, this paper looks to compare the application of the Theory of Functional Connections (TFC) with one based on least-squares support vector machines (LS-SVM). The TFC method uses a constrained expression, an expression that always satisfies the DE constraints, which transforms the process of solving a DE into solving an unconstrained optimization problem that is ultimately solved via least-squares (LS). In addition to individual analysis, the two methods are merged into a new methodology, called constrained SVMs (CSVM), by incorporating the LS-SVM method into the TFC framework to solve unconstrained problems. Numerical tests are conducted on four sample problems: One first order linear ordinary differential equation (ODE), one first order nonlinear ODE, one second order linear ODE, and one two-dimensional linear partial differential equation (PDE). Using the LS-SVM method as a benchmark, a speed comparison is made for all the problems by timing the training period, and an accuracy comparison is made using the maximum error and mean squared error on the training and test sets. In general, TFC is shown to be slightly faster (by an order of magnitude or less) and more accurate (by multiple orders of magnitude) than the LS-SVM and CSVM approaches.

The Contribution of Backbone Electrostatic Repulsion to DNA Mechanical Properties is Length-Scale-Dependent.

The mechanics of DNA bending is crucially related to many vital biological processes. Recent experiments reported anomalous flexibility for DNA on short length scales, calling into doubt the validity of the harmonic worm-like chain (WLC) model in this region. In the present work, we systematically probed the bending dynamics of DNA at different length scales. In contrast to the remarkable deviation from the WLC description for DNA duplexes of less than three helical turns, our atomistic studies indicate that the neutral "null isomer" behaves in accord with the ideal elastic WLC and exhibits a uniform decay for the directional correlation of local bending. The backbone neutralization weakens the anisotropy in the effective bending preference and the helical periodicity of bend correlation that have previously been observed for normal DNA. The contribution of electrostatic repulsion to stretching cooperativity and the mechanical properties of DNA strands is length-scale-dependent: the phosphate neutralization increases the stiffness of DNA below two helical turns, but it is decreased for longer strands. We find that DNA rigidity is largely determined by base pair stacking, with electrostatic interactions contributing only around 10% of the total persistence length.

Molecular Crowding Modulates Actin Filament Mechanics and Structure

The cellular environment is crowded with high concentrations of macromolecules that significantly reduce the accessible volume limiting biomolecule interactions. Reductions in cellular volume can generate depletion forces that affect protein assembly and stability. The mechanical and structural properties of actin filaments play critical roles in various cellular functions including structural support, cell movement, division, and intracellular transport. Although the effects of molecular crowding on actin polymerization have been shown, how crowded environments affect filament conformations, dynamics, and mechanical properties is unknown. In this study, we investigate the effects of solution crowding on the modulations of filament mechanics and structure both in vitro and in silico. Direct visualization of filaments in the presence of crowding agents is achieved by fluorescence microscopy imaging, allowing for the quantification of filament thermal bending dynamics and mechanics. Biophysical analysis indicate that molecular crowding modulates thermal fluctuations, enhances filament's effective bending stiffness, and reduces average filament lengths. Utilizing the explicit molecular dynamics simulations, we demonstrate that molecular crowding alters filament conformations and structural properties indicating overall compaction and stabilization that are directly coupled to filament mechanics. Taken together, our study suggests the interplay between excluded volume effects and non‐specific interactions raised from molecular crowding may modulate actin filament mechanics and structure.Support or Funding InformationThis study was supported by the UCF start‐up fund and In‐House grant for H.K. The authors would like to thank the National Science Foundation for support of this work through REU site EEC 1560007. We acknowledge the computational time from UCF stokes cluster.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Elastic and Irreversible Bending of Tree and Shrub Branches Under Cantilever Loads.

Tree and shrub branches subjected to cantilever loads such as intercepted snowfall undergo, in addition to the familiar instantaneous elastic bending, a conspicuous retarded-elastic bending, which is commonly 30–50% of their instantaneous bending and occasionally even more. The resultant bending creep that occurs after loading also often includes a slow, time-dependent irreversible bending. These phenomena occur quite generally among woody plants of different major biomes, taxonomic groups, and structural types. We give some of branch bending viscoelasticity’s basic physical properties such as load dependence and stress relaxation. These properties belong to the secondary walls of branches’ xylem (wood) cells; some properties differ notably from those reported for primary cell walls, a difference for which we propose explanations. A method for separating the overlapping time courses of retarded-elastic and time-dependent irreversible bending shows that multiple retarded-elastic (“Kelvin”) elements of branches span a wide range of retardation times (a retardation spectrum, approximate examples of which we calculate), and that irreversible bending can occur in different cases either only in the first few h after loading, or more extensively through 24 h, or (rarely) for several days. A separate time-independent irreversible bending, permanent set, involving a substantial yield stress, also occurs. In three species of shrubs rapid irreversible bending began only several (up to 24) h after loading, implying an unusual kind of viscoelasticity. Deductions from the dynamics of bending suggest that retarded elasticity can help protect branches against breakage by wind gusts during storms. Irreversible bending probably contributes both to the form that tree and shrub crowns develop over the long term, involving progressive increase in the downward curvature and/or inclination of branches, and also to certain other, more specialized, developmental changes.

Three-dimensional flow structure, morphodynamics, suspended sediment, and thermal mixing at an asymmetrical river confluence of a straight tributary and curving main channel

Past field studies of confluence dynamics have focused mainly on experimental or small stream confluences and confluences of large rivers. Few studies have explored fluvial processes and forms at confluences of medium-size rivers, especially those where river planform varies from a straight alignment. This study examines changes in flow structure, bed morphology, sediment suspension, and mixing with changing incoming flow conditions at a river confluence where a straight tributary joins a curving main channel at the upstream end of a bend. Data include five sets of field measurements of three-dimensional velocity components, bed topography, acoustic backscatter intensity, and water-surface temperatures at the confluence of the curving Wabash River and its straight tributary, the Embarras River. Results show that, in contrast to large river confluences, channel-scale helical motion is a prominent feature of flow structure at this confluence. Dual counter-rotating helical cells, separated by a distinct shear layer, develop over a region of scour within the confluence and contribute to maintenance of scour by sweeping sediment away from this region. Helical motion develops through channel curvature and flow deflection within the confluence. The location and geometry of the scour hole are subject to change depending on the relative momentum fluxes of the two rivers with the zone of scour shifting outward and enlarging as the momentum flux of the tributary increases relative to the momentum flux of the main river. Patterns of backscatter intensity, used here as a surrogate for suspended sediment concentration, confirm that near-bed suspended sediment moves around the scour hole. The thermal mixing interface between the two rivers corresponds to the position of the shear layer, and thermal mixing at the surface within the immediate vicinity of the confluence is limited. The hydrodynamics, morphodynamics, and patterns of sediment suspension and thermal mixing at this river confluence reflect a combination of confluence and bend dynamics.

Identifying the dominant physical processes for mixing in full-scale raceway tanks

Abstract Open racetrack flumes represent the most common reactor for algae cultivation in the biodiesel industry, however, despite numerous experimental and numerical studies into reactor modifications, conditions remain suboptimal for algal growth. In response, a full-scale racetrack flume was constructed at the Ecohydraulics and Ecomorphodynamics Laboratory at the University of Illinois. Experiments on the racetrack flume were conducted for various depth and velocity conditions, using acoustic doppler velocimetry and surface particle velocimetry to characterize mean and turbulent velocity statistics, and dissolved oxygen measurements to investigate the effect of turbulent structures on gas transfer at the water-air interface. Longitudinal bed modifications were introduced to induce secondary flows in the straight portions of the flume. Semicircular and triangular bars of two different sizes were tested in an effort to increase the transfer velocity at the free surface. A range of flow structures were observed including secondary currents of Prandtl's first and second kinds, vortex shedding off of bend vanes, and periodic oscillations in surface lateral currents. Findings indicate that bend dynamics introduce the strongest and most resilient flow structures, and any attempt to induce vertical mixing or accelerate transfer velocities at the free surface will need to utilize or overwhelm these existing structures.

Effects of Channel Forming Peptides on Lipid Bilayer Dynamics and Leaflet Coupling

Altering the material properties of lipid bilayers has been shown to affect the biological activity of a number of channel-forming peptides and proteins. A prototypical example is gramicidin, in which the channel formation and lifetime directly depends on the lipid membrane in which it is embedded. However, less is known about how a membrane-spanning channel affects the lipid bilayer properties, particularly the elasticity. Here we use neutron spin echo spectroscopy (NSE) to measure both the collective bending and thickness fluctuation dynamics in dimyristoylphosphatidylcholine (DMPC) and dipalmitoylphosphatidylcholine (DPPC) bilayers containing gramicidin at low peptide/lipid ratios. At these low concentrations, gramicidin incorporation did not have a measurable effect on the average bilayer structure but significantly impacted the collective membrane dynamics. The bending modulus of DMPC membranes increased with increasing gramicidin concentration, while the trend in DPPC was non-monotonic and first decreased at low gramicidin concentrations before increasing at higher concentrations. In contrast, the thickness fluctuation amplitude increased with increasing gramicidin concentration in both the DMPC and DPPC lipid bilayers. Notably, combining the bending and thickness fluctuation results revealed that the seemingly disparate concentration trends in the DMPC and DPPC lipid bilayers were both consistent with an increase in coupling between the bilayer leaflets with increasing gramicidin concentration. Together these results demonstrate that channel formation can have considerable effects on the surrounding lipid membrane elasticity and highlight the interplay between lipids and peptides in determining the membrane dynamics.

Nonequilibrium dynamics of probe filaments in actin-myosin networks.

Active dynamic processes of cells are largely driven by the cytoskeleton, a complex and adaptable semiflexible polymer network, motorized by mechanoenzymes. Small dimensions, confined geometries, and hierarchical structures make it challenging to probe dynamics and mechanical response of such networks. Embedded semiflexible probe polymers can serve as nonperturbing multiscale probes to detect force distributions in active polymer networks. We show here that motor-induced forces transmitted to the probe polymers are reflected in nonequilibrium bending dynamics, which we analyze in terms of spatial eigenmodes of an elastic beam under steady-state conditions. We demonstrate how these active forces induce correlations among the mode amplitudes, which furthermore break time-reversal symmetry. This leads to a breaking of detailed balance in this mode space. We derive analytical predictions for the magnitude of resulting probability currents in mode space in the white-noise limit of motor activity. We relate the structure of these currents to the spatial profile of motor-induced forces along the probe polymers and provide a general relation for observable currents on two-dimensional hyperplanes.

Molecular Structure, Equilibrium Conformation, and Ring-Puckering Motion in 1,1,3,3-Tetramethylcyclobutane. An Electron-Diffraction Investigation Augmented by Molecular Orbital and Normal Coordinate Calculations.

The molecule cyclobutane (CB) has a nonplanar carbon skeleton folded around a line connecting diagonally opposite atoms. The puckering angle (the change from planarity) of ∼30° is generally attributed to steric repulsion between the four sets of adjacent methylene groups that would be opposed in a planar ring and is relieved by the puckering. According to this criterion, a similar molecule, 1,1,3,3-tetramethylcyclobutene (TMCB), in which adjacent methylene groups do not exist, would be expected to have a planar ring in the equilibrium form. We have investigated the structure of TMCB to test this expectation. Two models were designed for the tests: one having D2h symmetry (planar ring) and one of C2v symmetry (nonplanar ring). Each model incorporated the dynamics of large-amplitude bending around a line joining the methylene groups. Our results suggest the D2h model is to be preferred. Dynamic averages (rg/Å; ∠g/deg) of the more important distances and angles in the D2h model with estimated 2σ uncertainties, are as follows. <C-H> = 1.105 (5), C1-C5 = 1.524 (10), C1-C2 = 1.559 (11), C2-C1-C4 = 87.4 (8), C1-C2-C3 = 92.0 (7), C5-C1-C6 = 109.0 (13), and C2-C1-C5 = 115.8 (8). The large-amplitude bending of the ring leads to a thermal average value of the folding angle equal to 177.1°. The results, including the differences between TMCB and CB, are discussed.

The Synergistic Effects of Lipids and Peptides on Membrane Dynamics

There is a growing appreciation that the membrane physical properties are essential to cell and protein function. Simply altering the thickness of model membranes has been shown to influence the biological activity of several proteins, while incorporating peptides into lipid membranes also is known to affect the bilayer structural properties. Clearly there is a synergy in lipid-protein interactions in determining the membrane properties; however, the nature of these interactions are not well understood. Here we use a combination of small angle scattering techniques and neutron spin echo spectroscopy (NSE) to investigate the effects of incorporating a small peptide on both the structure and dynamics of model membrane systems. In particular, we investigated the effects of the antimicrobial peptides gramicidin and alamethecin on the lipid bilayer structure using small angle x-ray and neutron scattering. The structural studies were complemented by NSE experiments to probe the collective bending and thickness fluctuation dynamics in these model systems. Notably, the NSE results revealed enhanced thickness fluctuation dynamics in lipid bilayers containing low concentration of gramicidin that were dampened with increasing peptide concentration. An enhancement in dynamics was not seen in bilayers containing alamethicin, suggesting that the dynamics not only depend on peptide concentration, but also peptide orientation within the membrane

Bending modes and transition criteria for a flexible fiber in viscous flows

The present paper follows our previous work in which a coupling approach of smoothed particle hydrodynamics (SPH) and element bending group (EBG) was developed for modeling the interaction of viscous incompressible flows with flexible fibers. It was also shown that a flexible object may experience drag reduction because of its reconfiguration due to fluid force on it. However, the reconfiguration of deformable bodies does not always result in drag reduction as different deformation patterns can result in different drag scales. In the present work, we studied the bending modes of a flexible fiber in viscous flows using the presented SPH and EBG coupling approach. The flexible fiber is immersed in a fluid and is tethered at its center point, while the two ends of the fiber are free to move. We showed that the fiber undergoes four different bending modes: stable U-shape, slight swing, violent flapping, and stable closure modes. We found there is a transition criterion for the flexible fiber from slight swing, suddenly to violent flapping. We defined a bending number to characterize the bending dynamics of the interaction of flexible fiber with viscous fluid and revealed that this bending number is relevant to the non-dimensional fiber length. We also identified the critical bending number from slight swing mode to violent flapping mode.

Stretching and bending dynamics in triatomic ultralong-range Rydberg molecules

We investigate polyatomic ultralong-range Rydberg molecules consisting of three ground state atoms bound to a Rydberg atom via $s$- and $p$-wave interactions. By employing the finite basis set representation of the unperturbed Rydberg electron Green's function we reduce the computational effort to solve the electronic problem substantially. This method is subsequently applied to determine the potential energy surfaces of triatomic systems in electronic $s$- and $p$-Rydberg states. Their molecular geometry and resulting vibrational structure are analyzed within an adiabatic approach that separates the vibrational bending and stretching dynamics. This procedure yields information on the radial and angular arrangement of the nuclei and indicates in particular that kinetic couplings between bending and stretching modes induce a linear structure in triatomic $l=0$ ultralong-range Rydberg molecules.

Dynamic Coupling among Protein Binding, Sliding, and DNA Bending Revealed by Molecular Dynamics.

Protein binding to DNA changes the DNA's structure, and altered DNA structure can, in turn, modulate the dynamics of protein binding. This mutual dependency is poorly understood. Here we investigated dynamic couplings among protein binding to DNA, protein sliding on DNA, and DNA bending by applying a coarse-grained simulation method to the bacterial architectural protein HU and 14 other DNA-binding proteins. First, we verified our method by showing that the simulated HU exhibits a weak preference for A/T-rich regions of DNA and a much higher affinity for gapped and nicked DNA, consistent with biochemical experiments. The high affinity was attributed to a local DNA bend, but not the specific chemical moiety of the gap/nick. The long-time dynamic analysis revealed that HU sliding is associated with the movement of the local DNA bending site. Deciphering single sliding steps, we found the coupling between HU sliding and DNA bending is akin to neither induced-fit nor population-shift; instead they moved concomitantly. This is reminiscent of a cation transfer on DNA and can be viewed as a protein version of polaron-like sliding. Interestingly, on shorter time scales, HU paused when the DNA was highly bent at the bound position and escaped from pauses once the DNA spontaneously returned to a less bent structure. The HU sliding is largely regulated by DNA bending dynamics. With 14 other proteins, we explored the generality and versatility of the dynamic coupling and found that 6 of the 15 assayed proteins exhibit the polaron-like sliding.

Cytokinins influence root gravitropism via differential regulation of auxin transporter expression and localization in Arabidopsis.

Redirection of intercellular auxin fluxes via relocalization of the PIN-FORMED 3 (PIN3) and PIN7 auxin efflux carriers has been suggested to be necessary for the root gravitropic response. Cytokinins have also been proposed to play a role in controlling root gravitropism, but conclusive evidence is lacking. We present a detailed study of the dynamics of root bending early after gravistimulation, which revealed a delayed gravitropic response in transgenic lines with depleted endogenous cytokinins (Pro35S:AtCKX) and cytokinin signaling mutants. Pro35S:AtCKX lines, as well as a cytokinin receptor mutant ahk3, showed aberrations in the auxin response distribution in columella cells consistent with defects in the auxin transport machinery. Using invivo real-time imaging of PIN3-GFP and PIN7-GFP in AtCKX3 overexpression and ahk3 backgrounds, we observed wild-type-like relocalization of PIN proteins in the columella early after gravistimulation, with gravity-induced relocalization of PIN7 faster than that of PIN3. Nonetheless, the cellular distribution of PIN3 and PIN7 and expression of PIN7 and the auxin influx carrier AUX1 was affected in AtCKX overexpression lines. Based on the retained cytokinin sensitivity in pin3 pin4 pin7 mutant, we propose the AUX1-mediated auxin transport rather than columella-located PIN proteins as a target of endogenous cytokinins in the control of root gravitropism.

Influence of Charge on the Elastic Properties of Lipid Membranes

Lipid membrane elastic properties play an important role in the membrane deformations and dynamic morphological transitions necessary for cell function. A key elastic property underlying these dynamics is the bending rigidity, motivating significant research efforts to quantify the effects of lipid structure and additives on the membrane bending modulus. To date, the majority of experimental research has focused on the dynamics of model membrane systems composed of zwitterionic lipids; however, most biomembranes are negatively charged at physiological conditions due to the presence of charged lipid headgroups. Here we study the bending dynamics of negatively-charged phosphatidylglycerol (PG) bilayers using neutron spin echo spectroscopy. Our results show that the charged lipid bilayers are softer than analogous zwitterionic phosphatidylcholine (PC) bilayers in both the gel and fluid phases at low ionic strength conditions. Interestingly, theoretical predictions indicate that the opposite should be true and that the bending rigidity should increase with increasing surface charge. We propose that this discrepancy is due to charged-related differences in the area per headgroup and lipid hydration between PG and PC bilayers that are not considered by existing theoretical models. Our results provide new insights into the influence of charge on the membrane elastic properties and demonstrate how these dynamics are coupled to charge effects on the membrane structure.

Dynamic bending of bionic flexible body driven by pneumatic artificial muscles(PAMs) for spinning gait of quadruped robot

The body of quadruped robot is generally developed with the rigid structure. The mobility of quadruped robot depends on the mechanical properties of the body mechanism. It is difficult for quadruped robot with rigid structure to achieve better mobility walking or running in the unstructured environment. A kind of bionic flexible body mechanism for quadruped robot is proposed, which is composed of one bionic spine and four pneumatic artificial muscles(PAMs). This kind of body imitates the four-legged creatures’ kinematical structure and physical properties, which has the characteristic of changeable stiffness, lightweight, flexible and better bionics. The kinematics of body bending is derived, and the coordinated movement between the flexible body and legs is analyzed. The relationship between the body bending angle and the PAM length is obtained. The dynamics of the body bending is derived by the floating coordinate method and Lagrangian method, and the driving force of PAM is determined. The experiment of body bending is conducted, and the dynamic bending characteristic of bionic flexible body is evaluated. Experimental results show that the bending angle of the bionic flexible body can reach 18°. An innovation body mechanism for quadruped robot is proposed, which has the characteristic of flexibility and achieve bending by changing gas pressure of PAMs. The coordinated movement of the body and legs can achieve spinning gait in order to improve the mobility of quadruped robot.

Hydrogel Nanofilaments via Core-Shell Electrospinning.

Recent biomedical hydrogels applications require the development of nanostructures with controlled diameter and adjustable mechanical properties. Here we present a technique for the production of flexible nanofilaments to be used as drug carriers or in microfluidics, with deformability and elasticity resembling those of long DNA chains. The fabrication method is based on the core-shell electrospinning technique with core solution polymerisation post electrospinning. Produced from the nanofibers highly deformable hydrogel nanofilaments are characterised by their Brownian motion and bending dynamics. The evaluated mechanical properties are compared with AFM nanoindentation tests.