Soft Membrane Research Articles

Minimizing Crinkling of Soft Specimens Using Holey Gold Films on Molybdenum Grids for Cryogenic Electron Microscopy.

We introduce a novel composite holey gold support that prevents cryo-crinkling and reduces beam-induced motion of soft specimens, building on the previously introduced all-gold support. The composite holey gold support for high-resolution cryogenic electron microscopy of soft crystalline membranes was fabricated in two steps. In the first step, a holey gold film was transferred on top of a molybdenum grid. In the second step, a continuous thin carbon film was transferred onto the holey gold film. This support (Au/Mo grid) was used to image crystalline synthetic polymer membranes. The low thermal expansion of Mo is not only expected to avoid cryo-crinkling of the membrane when the grids are cooled to cryogenic temperatures, but it may also act to reduce whatever crinkling existed even before cooling. The Au/Mo grid exhibits excellent performance with specimens tilted to 45°. This is demonstrated by quantifying beam-induced motion and differences in local defocus values. In addition, images of specimens on the Au/Mo grids that are tilted at 45° show high-resolution information of the crystalline membranes that, after lattice-unbending, extends beyond 1.5 Å in the direction perpendicular to the tilt axis.

Dragonfly wing-inspired architecture makes a stiff yet tough healable material

<h2>Summary</h2> Mechanically robust and healable polymers are in high demand for the intelligent architecture, aerospace engineering, and auto industry; however, most of them suffer from brittle fracture owing to the inherent conflict between stiffness and toughness within polymer systems. Inspired by the microstructure of dragonfly wings, we show how brittle, stiff, and healable materials can become defect tolerant by strategies ranging from molecular design to structural processing. Transition metal carbides/carbonitrides form an interconnected mechanical framework, similar to the rigid nervure in dragonfly wings, to stabilize the growth and slow down the extension of crack, while the initially glassy healing polymer closely bonds to rigid framework through powerful interfacial supramolecular interactions, playing a key role in the soft membrane dissipating stress energy. Compared with initial polymers, the obtained SP/MXene (SPM) nanocomposite exhibits an increase in fracture toughness and flexural strength (54.3- and 25.0-fold, respectively), exceptional thermal stability, mechanical and functional repairability, and good electromagnetic interference shielding.

A Soft On/Off Switch Based on the Electrochemically Reversible H-J Interconversion of a Porphyrin Membrane at an Electrified Liquid|Liquid Interface

Soft molecular assemblies that respond reversibly to external stimuli are attractive materials as on/off switches, in optoelectronic, memory and sensor technologies. In this presentation, the reversible structural rearrangement of a soft porphyrin membrane under an electrical potential stimulus in the absence of solid-state architectures will be presented.The free-floating porphyrin membrane lies at the interface between immiscible aqueous and organic electrolyte solutions and is formed through interfacial self-assembly of zinc(II) meso-tetrakis(4-carboxyphenyl)porphyrins (ZnPor). A potential difference between the two immiscible electrolyte solutions induces the intercalation of bis(triphenylphosphoranylidene)ammonium cations from the organic electrolyte that exchange with protons in the porphyrin membrane. In situ UV/vis absorbance spectroscopy shows that this ionic intercalation and exchange induces a structural interconversion of the individual porphyrin molecules in the membrane from an H- to a J-type molecular configuration. These structural rearrangements are reversible over 30 potential cycles. In situ polarisation-modulation fluorescence spectroscopy further provides clear evidence of structural interconversion of the porphyrin membrane, as intercalation of the organic electrolyte cations significantly affects the latter’s emissive properties. By adjusting the pH of the aqueous phase, additional control of the electrochemically reversible structural interconversion can be achieved, with total suppression at pH 3.The work presented herein opens new opportunities to investigate the use of structurally dynamic soft supramolecular porphyrin assemblies at the interface between two immiscible electrolyte solution (ITIES) as switchable on/off responsive nanomaterials, with applications in optoelectronic, memory and sensor devices. Figure 1

A MEMS-based electromagnetic membrane actuator utilizing bonded magnets with large displacement

In a previous study, microfabricated bonded magnets have been utilized in MEMS-based electromagnetic membrane actuators (EMMAs) to drive micropumps. However, to maintain the flexibility of the membrane the packing density of the spin-coated bonded magnets needed to be small (6 vol%) and this together with a strong self-demagnetization effect meant that the force generated was weak. As a result, the maximum displacement achieved was only several microns. To overcome this problem, we proposed fabricating bonded magnets using micro compression molding with a soft membrane mold in order to realize both a high packing density and a flexible membrane. The grooves (0.3 mm × 5 mm × t0.3 mm) in the PDMS membrane were filled with a mixture of NdFeB magnetic powder and wax powder. A packing density of 50 vol% for the bonded magnets was realized without undue influence on the flexibility of the membrane. A fine-pitch magnetization pattern was also used to decrease the self-demagnetization effect and thereby improve actuator performance. The experimental results show that the maximum force generated and the maximum displacement achieved using the fabricated EMMAs (12 mm × 12 mm × t1.1 mm) were 2.2 mN and 100 μm, respectively, at the power consumption of 4 W.

Membrane Lipids and Cellular Water Modulate the G‐Protein–Coupled Receptor Activation

G-protein-coupled receptors (GPCRs) are a pivotal superfamily of seven-helix transmembrane receptors responsible for the transduction of stimuli across cellular membranes. They are the targets of ~30% of the pharmaceuticals currently in the market. Understanding how the soft membrane matter (membrane Lipids and Cellular Water) influences the structural changes during the activation of GPCRs is crucial to discovering and developing novel GPCR-targeted drugs. Their dynamic conformational ensembles encompassing various inactive and active states can be biased by the lipids and surrounding aqueous environments [1]. By using different polyethylene glycol (PEG) solutions, we explored the effect of osmotic pressure and lipid bilayer composition on the metarhodopsin equilibrium of the archetypical GPCR rhodopsin in native membranes and POPC recombinant membranes [2]. Our results show a flood of ~80 water molecules into the rhodopsin interior during photoactivation, forming a solvent-swollen Meta-II active state [3]. Under applied osmotic pressure, the overall equilibrium generally shifted to Meta-I. Dehydrating conditions favor Meta-I through the efflux of water from the protein interior while increasing bilayer thickness and the monolayer spontaneous curvature favor Meta-II. The osmotic effect on the protein is more significant than the effect of the lipid bilayer. However, small osmolytes favored the Meta-II state at lower concentrations because they can penetrate the protein core giving a lower excluded volume, decreasing the osmotic effect on the protein and favoring the Meta-II state. Furthermore, the metarhodopsin equilibrium was shifted towards the Meta-I state in POPC recombinant membranes compared to the native membrane environment. Analysis of transducin C-terminal peptide-binding isotherms revealed that the binding affinity is significantly decreased when the lipid environment is changed from the native lipids to POPC lipids. The POPC lipid membrane has zero-spontaneous curvature that shifts the equilibrium towards the more compact, inactive Meta-I state. By contrast, the native lipid membrane environment has a negative spontaneous curvature that favors the more expanded state of Meta-II. Our results delineate the crucial role of soft matter in regulating the metarhodopsin equilibrium in a membrane environment. [1] M.F. Brown (2017) Annu. Rev. Biophys. 46, 379-410. [2] N. Weerasinghe et al. (2018) Biophys. J. 114, 274a. [3] U. Chawla et al. (2020) Angew. Chem. Int. Ed. doi: https://doi.org/10.1002/ange.202003342.

Hydration Drives Activation of the G‐Protein‐Coupled Receptor Rhodopsin

G-protein-coupled receptors (GPCRs) are a pivotal superfamily of seven-helix transmembrane receptors responsible for the transduction of stimuli across cellular membranes. They are the targets of ~30% of the pharmaceuticals currently in the market. Understanding how the soft membrane matter (lipids and water) influences the structural changes during the activation of GPCRs is crucial to discovering and developing novel GPCR-targeted drugs [1]. Here, we assessed the effects of hydration on the conformational dynamics of GPCRs by subjecting the archetypical GPCR-rhodopsin in native retinal disk membranes to varying osmotic pressures using polyethylene glycol (PEG) solutions of different molar mass [2,3]. The metastable activation equilibrium of rhodopsin (Keq) after photoexcitation was quantified using UV-visible spectroscopy. Analysis of the results using thermodynamic relations revealed for the first time an influx of ~80-100 water molecules flooding into the rhodopsin interior during photoactivation, validating previous molecular dynamics (MD) simulations [4]. Both applied osmotic pressure and the osmolyte size affected the metarhodopsin equilibrium. Dehydrating conditions generally favored the closed inactive Meta-I state through an efflux of water from the protein interior, while small penetrating osmolytes stabilized the expanded active Meta-II conformation in low concentration regimes. The pH titration curves for the metarhodopsin equilibrium in the presence of various PEG osmolytes showed that hydration is coupled to activation via modulation of the pKA of Glu134 of the conserved E(D)RY sequence motif. By changing water availability, osmotic stress perturbs the dielectric constant characterizing the Glu134 microenvironment and the thermodynamics of its protonation. Activation of rhodopsin is contingent upon the change in electrostatic microenvironments by rearranging water molecules within the protein conformation, dramatically recasting the role of soft matter in biological signal transduction. [1] M.F. Brown (2017) Annu. Rev. Biophys. 46, 379-410. [2] U. Chawla et al. (2020) Angew. Chem. Int. Ed. doi:10.1002/anie.202003342. [3] N. Weerasinghe et al. (2018) Biophys. J. 114, 274a. [4] N. Leioatts et al. (2014) Biochemistry 53, 376−385.

Synthesis and characterization of poly(ethylene oxide) based copolymer membranes for efficient gas/vapor separation: Effect of PEO content and chain length

Due to their high CO2 selectivity, poly(ethylene oxide) (PEO)-based membranes have raised attention to CO2-related gas separations. Nevertheless, the fabrication of such membranes is quite challenging as PEO suffers from poor film forming ability and high crystallization tendency, which restricts gas transport. In this work, a new series of CO2 and water selective aromatic polyethers bearing flexible PEO side chains prepared via a polycondensation reaction is reported. The synthesized copolymers are mechanically and thermally robust, completely amorphous even at 49 wt% PEO and form flexible, soft membranes. As observed, membrane permeation properties are significantly influenced by both PEO chain length and PEO loading. CO2 permeability increases with PEO loading, which is assigned mainly to the enhanced CO2 solubility contribution of the PEO segments. In particular, when PEO content is higher than 39 wt%, copolymers go from the glassy to the rubbery state, thus resulting in increased CO2 permeability due to the significant contribution of favorable CO2-PEO interactions along with a minimal diffusivity increase. CO2 selectivities over H2 and CH4 also increase as a function of PEO content mainly due to the strong solubility contribution on CO2 permeability enhancement. The copolymer with the highest PEO loading (49 wt%) and the longer PEO chain (750) shows both a maximum CO2 permeability of 11.2 Barrer and maximum ideal CO2/H2 and CO2/CH4 selectivities of 9.6 and 68, respectively, at 30 °C. The CO2/H2 ideal selectivity of 9.6 surpasses the upper bound. Moreover, these copolymers show high water permeability that is also strongly dependent on the PEO weight content and PEO chain length. Likewise, the highest water permeability (30,100 Barrer) is delivered by the copolymer with the highest PEO loading (49 wt%) and the longer PEO chain (750) at 30 °C. The highest H2O selectivity over CO2 (2688) observed for this copolymer is comparable with other PEO-based copolymers having excellent separation performance. These results support the possible application of these copolymers in hydrogen purification and dehydration of CO2 gas streams.

Generation of GelSight Tactile Images for Sim2Real Learning

Most current works in Sim2Real learning for robotic manipulation tasks leverage camera vision that may be significantly occluded by robot hands during the manipulation. Tactile sensing offers complementary information to vision and can compensate for the information loss caused by the occlusions. However, the use of tactile sensing is restricted in the Sim2Real research due to no simulated tactile sensors being available. To mitigate the gap, we introduce a novel approach for simulating a GelSight tactile sensor in the commonly used Gazebo simulator. Similar to the real GelSight sensor, the simulated sensor can produce high-resolution images from depth-maps captured by a simulated optical sensor, and reconstruct the interaction between the touched object and an opaque soft membrane. It can indirectly sense forces, geometry, texture and other properties of the object and enables Sim2Real learning with tactile sensing. Preliminary experimental results have shown that the simulated sensor could generate realistic outputs similar to the ones captured by a real GelSight sensor. All the materials used in this letter are available at https://danfergo.github.io/gelsight-simulation.

Elastic wetting: Substrate-supported droplets confined by soft elastic membranes

While classical wetting is well captured by the famous Young's equation and classical bulge and blister models are readily available, there is limited understanding of a micro- or nano-scale droplet being covered by an ultrasoft elastic membrane. We call this phenomenon elastic wetting to feature the interplay between the liquid's surface tension and the membrane's elastic deformation. Examples of elastic wetting include cell blebs and 2D material bubbles, where the membrane thickness ranges from microns to sub-nanometers. In this work, we study the equilibrium of elastic wetting and solve for the profiles and the pressure-volume relations of the membrane-confined droplets. We show that in elastic wetting, the pressure across the membrane/droplet interface can be described by a simple superposition of the Young-Laplace equation and the nonlinear membrane equation. Furthermore, nonlinear elasticity, geometric nonlinearity, and surface tension, together with membrane-substrate adhesion, interweave at the contact line, leading to rich membrane-confined droplet configurations. Finally, we examine the effect of substrate compliance on elastic wetting and find that the rigid substrate assumption approximates well for most of the existing experiments in the literature. Our results provide fundamental mechanistic insights into the various phenomena of elastic wetting as well as viable means to extract physical parameters including the bubble pressure and the interface energies.

Titanium Meshes in Guided Bone Regeneration: A Systematic Review

The presence of satisfactory bone volume is fundamental for the achievement of osseointegration. This systematic review aims to analyse the use of titanium meshes in guided bone regeneration in terms of bone gain, survival and success rates of implants, and percentages of exposure. An electronic search was conducted Articles were selected from databases in MEDLINE (PubMed), SCOPUS, Scielo, and Cochrane Library databases to identify studies in which bone regeneration was performed through particulate bone and the use of titanium meshes. Twenty-one studies were included in the review. In total, 382 patients, 416 titanium meshes, and 709 implants were evaluated. The average bone gain was 4.3 mm in horizontal width and 4.11 mm in vertical height. The mesh exposure was highly prevalent (28%). The survival rate of 145 simultaneous implants was 99.5%; the survival rate of 507 delayed implants was 99%. The success rate of 105 simultaneous implants was 97%; the success rate of 285 delayed implants was 95.1%. The clinical studies currently available in the literature have shown the predictability of this technique. It has a high risk of soft tissue dehiscence and membrane exposure although the optimal management of membrane exposition permits obtaining a sufficient bone regeneration volume and prevents compromising the final treatment outcome.

Mechanical Properties of Soft Biological Membranes for Organ-on-a-Chip Assessed by Bulge Test and AFM.

Advanced in vitro models called "organ-on-a-chip" can mimic the specific cellular environment found in various tissues. Many of these models include a thin, sometimes flexible, membrane aimed at mimicking the extracellular matrix (ECM) scaffold of in vivo barriers. These membranes are often made of polydimethylsiloxane (PDMS), a silicone rubber that poorly mimics the chemical and physical properties of the basal membrane. However, the ECM and its mechanical properties play a key role in the homeostasis of a tissue. Here, we report about biological membranes with a composition and mechanical properties similar to those found in vivo. Two types of collagen-elastin (CE) membranes were produced: vitrified and nonvitrified (called "hydrogel membrane"). Their mechanical properties were characterized using the bulge test method. The results were compared using atomic force microscopy (AFM), a standard technique used to evaluate the Young's modulus of soft materials at the nanoscale. Our results show that CE membranes with stiffnesses ranging from several hundred of kPa down to 1 kPa can be produced by tuning the CE ratio, the production mode (vitrified or not), and/or certain parameters such as temperature. The Young's modulus can easily be determined using the bulge test. This method is a robust and reproducible to determine membrane stiffness, even for soft membranes, which are more difficult to assess by AFM. Assessment of the impact of substrate stiffness on the spread of human fibroblasts on these surfaces showed that cell spread is lower on softer surfaces than on stiffer surfaces.

Simple and Reliable Fabrication Method for Polydimethylsiloxane Dielectric Elastomer Actuators Using Carbon Nanotube Powder Electrodes

Dielectric elastomer actuators (DEAs) are energy efficient, compact, and operate silently. DEAs consist of an elastomer membrane sandwiched between two stretchable electrodes. Optimizing the quality of both the elastomer and the stretchable electrodes is essential to improve the DEAs performance. Herein, novel strategies are reported to achieve fast, reliable, and low‐cost fabrication of DEAs. The strategies utilize a soft brush to directly pattern carbon nanotube (CNT) powder on the elastomer membrane and tune the mechanical and surface‐adhesiveness characteristics of a polydimethylsiloxane (PDMS) membrane by altering the mixing ratio of the curing agent and base polymer. A uniaxial engineering tensile test on PDMS indicates that a softer material is formed when less curing agent is used. The softer PDMS has a sticky surface, which allows the CNT powder to be physically bound to the surface. Field‐emission scanning electron microscopy (FE‐SEM) images prove that the strong CNT network is formed on the surface of the elastomer. The electromechanical investigation also indicates that the electrical conductivity is improved for a stickier PDMS surface. The optimal performance of PDMS 30‐1 in static and cyclic DEA tests shows that the brushing of CNT combined with soft and sticky elastomer membranes can increase the DEA performance.

Wireless Magnetic Actuation with a Bistable Parity-Time-Symmetric Circuit

Magnetic forces in oscillating electronic circuits provide a versatile way to remotely actuate objects. However, practical control of these forces is challenging due to variations in the circuit configuration and noise. We show that these challenges can be overcome using a bistable parity-time-symmetric circuit. Due to nonlinear parity-time symmetry, the circuit automatically tracks one of two eigenmodes corresponding to resonant attraction and repulsion during variations in the operating configuration. We show that noise facilitates controllable switching between the modes, and experimentally demonstrate practical actuation by remotely driving a pendulum and a soft pump membrane.

All-in-one, wireless, fully flexible sodium sensor system with integrated Au/CNT/Au nanocomposites

Abstract Advancements in functional nanomaterials and wearable electronics have demonstrated the use of solid-state ion-selective electrodes (SS-ISEs) for human health applications. Existing devices, however, still rely on separate and multiple components of flexible sensors, interconnectors, and rigid data acquisition units, which limits the wearability of the entire system on the skin for continuous analyte monitoring. Here, this paper introduces an all-in-one, wireless, fully flexible, sodium detection system that integrates gold-carbon nanotube-gold (Au/CNT/Au) sensors and flexible thin-film circuits, together on a soft elastomeric membrane. The nanocomposite sensor includes electrochemically deposited Au nanoparticles on a CNT transducer to improve the conductivity, capacitance, and interfacial contact between materials. A set of experimental electrochemical analysis confirms the high stability of the SS-ISE based on Au/CNT/Au nanocomposites. At the same time, the thin-film system shows mechanical robustness and reliability, even with repetitive bending up to 500 cycles. The fully flexible, sensor-circuit integrated system demonstrates stable sodium measurements when mounted on the skin with minimized motion artifacts. The measured sensitivity of the sodium sensor is 55.5 ± 0.3 mV/decade, along with less than 3% change when the entire device is mounted on the skin with continuous movements. Overall, the presented comprehensive study, including nanomaterials, nano-microfabrication, electrochemistry, and electronics, shows the enormous potential of the wireless all-in-one sensor system for seamless integration with various types of skin-mounted wearable health monitors.

Soft Wireless Bioelectronics and Differential Electrodermal Activity for Home Sleep Monitoring.

Sleep is an essential element to human life, restoring the brain and body from accumulated fatigue from daily activities. Quantitative monitoring of daily sleep quality can provide critical feedback to evaluate human health and life patterns. However, the existing sleep assessment system using polysomnography is not available for a home sleep evaluation, while it requires multiple sensors, tabletop electronics, and sleep specialists. More importantly, the mandatory sleep in a designated lab facility disrupts a subject’s regular sleep pattern, which does not capture one’s everyday sleep behaviors. Recent studies report that galvanic skin response (GSR) measured on the skin can be one indicator to evaluate the sleep quality daily at home. However, the available GSR detection devices require rigid sensors wrapped on fingers along with separate electronic components for data acquisition, which can interrupt the normal sleep conditions. Here, we report a new class of materials, sensors, electronics, and packaging technologies to develop a wireless, soft electronic system that can measure GSR on the wrist. The single device platform that avoids wires, rigid sensors, and straps offers the maximum comfort to wear on the skin and minimize disruption of a subject’s sleep. A nanomaterial GSR sensor, printed on a soft elastomeric membrane, can have intimate contact with the skin to reduce motion artifact during sleep. A multi-layered flexible circuit mounted on top of the sensor provides a wireless, continuous, real-time recording of GSR to classify sleep stages, validated by the direct comparison with the standard method that measures other physiological signals. Collectively, the soft bioelectronic system shows great potential to be working as a portable, at-home sensor system for assessing sleep quality before a hospital visit.

Studies on Soft Interfacial Membranes: Macro to Micro, Static to Dynamic, and Interface to Line

Studies on Soft Interfacial Membranes: Macro to Micro, Static to Dynamic, and Interface to Line

A biocompatible polypyrrole membrane for biomedical applications.

Polypyrrole (PPy) is the most widely investigated electrically conductive biomaterial. However, because of its intrinsic rigidity, PPy has only been used either in the form of a composite or a thin coating. This work presents a pure and soft PPy membrane that is synergically reinforced with the electrospun polyurethane (PU) and poly-l-lactic acid (PLLA) fibers. This particular reinforcement not only renders the originally rather fragile PPy membrane easy to manipulate, it also prevents the membrane from deformation in an aqueous environment. Peel and mechanical tests confirmed the strong adhesion of the fibers and the significantly increased tensile strength of the reinforced membrane. Surface electrical conductivity and long-term electrical stability were tested, showing that these properties were not affected by the reinforcement. Surface morphology and chemistry were analyzed with scanning electron spectroscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). Material thermal stability was investigated with thermogravimetric analysis (TGA). Finally, the adhesion and proliferation of human skin keratinocytes on the membrane were assessed by Hoechst staining and the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. In conclusion, this membrane proves to be the first PPy-based soft conductive biomaterial that can be practically used. Its electrical conductivity and cytocompatibility promise a wide range of biomedical applications.

Evaluation of postoperative outcomes in patients following multi-level surgical reconstructions with the use Avive™ soft tissue membrane on nerve after traumatic injury of the upper extremity and lower extremity.

Background:Treatment of patients with traumatic axonotmesis presents challenges. Processed human umbilical cord membrane has been recently developed with improved handling and resorption time compared to other amniotic membrane wraps, and may be beneficial in nerve reconstruction. This study evaluates postoperative outcomes after traumatic peripheral nerve injury after placement of commercially available processed human umbilical cord membrane.Methods:We performed a prospective, single-center pilot study of patients undergoing multi-level surgical reconstruction for exposed, non-transected peripheral nerve. Functional outcomes including pain, range of motion, pinch and grip strength, and the QuickDASH and SF-36 patient-reported outcome measures were recorded, when possible, at the 1-week and 3, 6, and 9 months postop visit. One-tailed paired t-tests were performed to evaluate outcome improvement at final follow-up.Results:Twenty patients had processed human umbilical cord membrane placement without surgical complications. Mean follow-up was 7.5 months (range: 3–10 months) and mean age was 39 years (range: 15–65). Twelve (67%) patients were male, and the majority of placement sites were in the upper extremity (85%). Mean preoperative visual analog scale pain score was significantly reduced at most recent follow-up, as were QuickDASH scores. All patients had improved functional outcomes at the 9-month follow-up, and SF-36 outcomes at 9 months showed improvement across all dimensions.Conclusion:This study indicates that processed human umbilical cord membrane may be a useful adjunct in nerve surgery with noted improvements in postoperative function, pain, and patient-reported outcome measures. Future studies are needed to assess long-term outcomes after traumatic nerve injury treated with processed human umbilical cord membrane.

Synthesis of Mn-doped and anatase/rutile mixed-phase TiO2 nanofibers for high photoactivity performance

A soft membrane of Mn@TiO2 NFs was fabricated by an electrospinning and thermal annealing process. It shows a mixture phase and a palpably increased specific surface area, which ensured a pronounced enhancement of the photocatalytic activity.

A soft tissue fabricated using a freeze-drying technique with carboxymethyl chitosan and nanoparticles for promoting effects on wound healing

Objective(s): Many people suffer from skin injuries due to various problems such as burns and accidents. Therefore, it is essential to shorten treatment time and providing strategies that can control the progression of the wound that would be effective in wound healing process and also reduce its economic costs.Methods: The present study aimed to prepare a nanocomposite dressing (NCD)composed of carboxymethyl chitosan (CMC), and Fe2O3 nanoparticles by a method called freeze-drying (FD) technique. The effect of different weight percentages of Fe2O3 (0, 2.5, 5, and 7.5 wt%) reinforcement on mechanical and biological properties such as tensile strength, biodegradability, and cell behavior was evaluated. Also, the X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were used to characterize the soft porous membrane. The biological response in the physiological saline was performed to determine the rate of degradation of NCD in phosphate buffer saline (PBS) for a specific time.Results: The obtained results demonstrated that the wound dress was porousarchitecture with micron-size interconnections. In fact, according to the results, as the magnetite nanoparticles amount increases, the porosity increases too. On the other hand, the tensile strength was 0.32 and 0.85 MPa for the pure sample and the sample containing the highest percentage of magnetic nanoparticles, respectively.Besides, the cytotoxicity of this nanocomposite was determined by MTT assays for 7 days and showed no cytotoxicity toward the growth of fibroblasts cells and had proper in vitro biocompatibility. The obtained results revealed that NCD had remarkable biodegradability, biocompatibility, and mechanical properties. Therefore, NCD composed of CMC and Fe2O3 nanoparticles was introduced as a promising candidate for wound healing applications.Conclusions: According to the obtained results, the optimum NCD specimen with 5 wt% Fe2O3 has the best mechanical and biological properties.