Highly Elastic Research Articles

In-situ polymerization of dual monomers for constructing a highly elastic PAA-co-PAM network enables efficient and stable Carbon-based perovskite solar cells

During the preparation of carbon-based perovskite solar cells, the external stress applied to the carbon paste inevitably compresses the perovskite lattice, potentially damaging its structure and generating defects. This poses a significant threat to the efficiency and stability of devices. Herein, a dual monomer irregular in-situ polymerization method was developed to form a highly elastic network (acrylamide-co-acrylic acid, PAA-co-PAM) within perovskite films, serving as both a ligament to passivate defects and a buffer to improve film stability under stress. The results demonstrated that multiple active sites of PAA-co-PAM could simultaneously passivate positive and negative defects, which improved charge transport efficiency, reduced nonradiative recombination, and prolonged lifetime of carriers. Meanwhile, the cross-linking network in PAA-co-PAM exhibits high elasticity due to both internal hydrogen bonds between monomers and external hydrogen bonds between monomers and perovskite, resulting in films with exceptional structural stability and mechanical resilience. Notably, the corresponding device achieved the power conversion efficiency of 15.39%. Moreover, the unencapsulated photovoltaic device passivated by the elastic network exhibits better storage stability and mechanical stability compared to the control devices. This work provides a new perspective and insight for comprehensively enhancing the stability of carbon-based perovskite solar cells.

Intelligent and biocompatible cellulose aerogels featured with high-elastic and fast-hemostatic for epistaxis and wound healing

Nasal tamponade is a commonly employed and highly effective treatment method for preventing nasal bleeding. However, the current nasal packing hemostatic materials exhibit some limitations, such as low hemostatic efficiency, the potential for causing secondary injury when removed from the nasal cavity, limited intelligence in their design, and an inability to promote the healing of nasal mucosa wounds. Herein, we report the fabrication of a smart cellulose aerogel through the covalent cross-linking of carboxymethyl cellulose (CMC) macromolecules, while incorporating one-dimensional cellulose nanofibers (CNF) and two-dimensional MXene as reinforcing network scaffolds and conductive fillers. The abundant hydrogen and ether bonds in aerogels make them possess high elasticity in both dry and wet states, which can be compressed 100 times at 90 % deformation with a stress loss of <10 % under water. The highly elastic aerogels can be filled into the narrow nasal passages, pressuring the capillaries and reducing the amount of bleeding. Moreover, the strong interface between aerogels and blood can promote red blood cell aggregation, platelet adhesion and activation, activate intrinsic coagulation pathway and accelerate blood coagulation, resulting in excellent hemostatic ability. Furthermore, the aerogels exhibit excellent hemocompatibility and cytocompatibility, making them suitable for wound healing and capable of fully healing wounds within 15 days. Notably, the presence of MXene causes the aerogels to form a conductive network when exposed to blood, enabling them to perform real-time hemostatic monitoring without removing the dressing. This innovative biomedical aerogel, prepared from natural materials, shows excellent potential for applications in rapid nasal hemostasis.

Nanocomposite hydrogel for skin motion sensing – An antifreezing, nanoreinforced hydrogel with decorated AuNP as a multicrosslinker

In this study, we present a nanocomposite hydrogel designed for skin motion sensing. The hydrogel is based on poly(acrylamide) crosslinked with gold nanoparticles covalently bound to the polymer matrix, yielding a robust, highly elastic and conductive material. The choice of amino acid derivative – N,N’-diacryloylcystine salt (BISS) – as a crosslinker allows for the introduction of gold nanoparticles, due to the presence of sulfide groups in its structure. During the nanoparticle modification process, covalent bonds between gold and sulfur atoms are formed as the disulfide bond is cleaved. In result of this self-assembly process, a multifunctional Au–BISS crosslinker is formed, enhancing the material’s mechanical properties and introducing electrical conductivity. To confer anti-freezing properties and limit water evaporation, a binary mixture of water and glycerol was used. The resultant hydrogel exhibits high elasticity, strain sensitivity across a wide strain range and various types of deformation (elongation, bending, compression) with exceptional response time (120 ms) and recovery time (90 ms). The material’s cold-resistance, resilience, and conductivity make it well-suited for real-time monitoring of joint movements and speech recognition, with potential applications in electronic skin and healthcare monitoring devices.

Wet-Stable Lamellar Wood Sponge with High Elasticity and Fatigue Resistance Enabled by Chemical Cross-Linking.

The excessive consumption of fossil-based plastics and the associated environmental concerns motivate the increasing exploitation of sustainable biomass-based materials for advanced applications. Natural wood-derived lamellar wood sponges via a top-down approach have recently attracted significant attention; however, the insufficient compressive fatigue resistance and lack of structural stability in water limit their wide applications. Here, we report a facile chemical cross-linking strategy to tackle these challenges, by which the cellulose fibrils in the lamellas are covalently bridged to enhance their connectivity. The cross-linked wood sponges demonstrate high compressibility up to 70% strain and exceptional compressive fatigue resistance (∼5% plastic deformation after 10,000 cycles at 50% strain). The interfibrillar cross-linking inhibits the swelling of cellulose fibrils and preserves the arch-shaped lamellas of the sponge in water, endowing the wood sponge with excellent wet stability. Such highly elastic and wet-stable lamellar wood sponges offer a sustainable alternative to synthetic polymer-based sponges used in diverse applications.

Highly elastic, fatigue-resistant, antibacterial, conductive, and nanocellulose-enhanced hydrogels with selenium nanoparticles loading as strain sensors

The fabrication of highly elastic, fatigue-resistant and conductive hydrogels with antibacterial properties is highly desirable in the field of wearable devices. However, it remains challenging to simultaneously realize the above properties within one hydrogel without compromising excellent sensing ability. Herein, we fabricated a highly elastic, fatigue-resistant, conductive, antibacterial and cellulose nanocrystal (CNC) enhanced hydrogel as a sensitive strain sensor by the synergistic effect of biosynthesized selenium nanoparticles (BioSeNPs), MXene and nanocellulose. The structure and potential mechanism to generate biologically synthesized SeNPs (BioSeNPs) were systematically investigated, and the role of protease A (PrA) in enhancing the adsorption between proteins and SeNPs was demonstrated. Additionally, owing to the incorporation of BioSeNPs, CNC and MXene, the synthesized hydrogels showed high elasticity, excellent fatigue resistance and antibacterial properties. More importantly, the sensitivity of hydrogels determined by the gauge factor was as high as 6.24 when a high strain was applied (400–700 %). This study provides a new horizon to synthesize high-performance antibacterial and conductive hydrogels for soft electronics applications.

Preparation of highly elastic superhydrophobic CNF/Fe3O4 based materials modified in aqueous phase for oil-water separation

Magnetic superhydrophobic materials have broad application prospect in oil-water separation. In this study, a magnetic and superhydrophobic aerogel with lamellar structure was successfully prepared using cellulose nanofibrils (CNF) as the skeleton, Fe3O4 as the magnetic ion, 1H, 1H, 2H, 2H trialkylfluorooctane triethoxysilane (FS) and 3-(2-aminoethyl amino)-propyl trimethoxysilane (AS) as the combined modifier. The prepared aerogel shows lower density (38.63 mg/cm3), excellent magnetic (15.13 emu/g), high elasticity and good oil sorption properties (21 g/g). In addition, FS/AS also exhibits excellent mechanical properties and superhydrophobic ability (water contact angle (WCA) of 151.9 ± 1.4°), as it provides sufficient toughness and low surface energy for the layer-branch structure. It should be noted that the entire preparation process is carried out in the aqueous phase, without the use of any organic solvents, providing a green oil-water separation strategy.

Superhydrophobic and Highly Elastic Strain‐Sensing Fiber Embedded with Carbon Nanotubes and Aerogels Based on the Dipping and Drying Method

AbstractFor a fiber‐based strain sensor to be used as a wearable device, its conductivity and sensing characteristics should be stably maintained even during repeated mechanical movements. Additionally, the sensing characteristics should remain unaffected by external contaminants, such as water or sweat, as the sensor is expected to be in contact with the human body. In this study, a superhydrophobic and highly elastic strain‐sensing fiber with durability against continuous tension and contraction while maintaining a stable sensing performance even when in contact with water and sweat is developed. A carbon nanotube is embedded, which is a highly conductive material, inside a spandex fiber with high elasticity and shape recovery rate, enabling the stable measurement of repetitive joint movements under various strain conditions. Furthermore, a superhydrophobic silica aerogel is embedded inside the spandex fiber to facilitate stable sensing without malfunction even when exposed to external contaminants. The proposed strain‐sensing fiber can monitor joints of the human body during various movements, such as dumbbell pressing, squatting, walking, and running. Therefore, the study findings can contribute to the development of wearable healthcare devices that warrant reliable sensing.

Highly elastic photothermal nanofibrillated cellulose aerogels for solar-assisted efficient cleanup of viscous oil spill

Frequent oil spills and illegal industrial pollutant discharge cause ecological and resource damages, so it is necessary to establish efficient adsorption and recovery strategies for oils in wastewater. Herein, inspired by solar-driven viscosity-breaking, we propose a facile approach to fabricate multifunctional nanofibrillated cellulose-based aerogel with high elasticity, excellent photothermal conversion, efficient selective oil adsorption and antibacterial properties. Firstly, copper sulfide (CuS) nanoparticles were in situ deposited on the template of oxidative nanofibrillated cellulose (ONC), aiming at achieving efficient photothermal effect and antibacterial properties. Ethylene glycol diglycidyl ether (EGDE) was employed to establish multiple crosslinking network between CuS@ONC and polyethyleneimine (PEI). A thin hydrophobic PMTS layer deposited on the surface of aerogel via a facile gas-solid reaction ensured stable oil selectivity. The resulting composite aerogel can rapidly adsorb oil under solar self-heating, significantly reducing the adsorption time from 25 to 5 min. Furthermore, it exhibits excellent adsorption capacities for various oils, retaining over 92 % of its initial capacity even after 20 adsorption-desorption cycles, and the antibacterial properties extend its lifespan. This work offers a promising method for constructing multifunctional aerogels for efficient oil-water separation, especially beneficial for high-viscosity and high-melting-point oil cleanup.

Skin-like and highly elastic optical fiber strain sensor based on a knot-bend shape for human motion monitoring.

A simply designed, highly sensitive, stretchable, compact wearable, and skin-like optical fiber sensing instrument is designed and demonstrated for joint motion monitoring. The fiber sensing scheme comprises only a section of single-mode fiber (SMF) deformed in the knot-like configuration, which performs as a Mach-Zehnder interferometer (MZI) based on a modal coupling mechanism between the core and cladding modes of the deformed SMF section. This proposed optical fiber sensor based on a knot-like configuration is mounted onto wearable woven fabric and then garments on the limbs of a healthy human's body. As the flexion angle of the human limb is varied, the interference fringe coding based on the spectral shift difference of the periodical transmission spectra is perceived. The proposed wearable optical fiber sensor exhibits excellent sensitivities from around -0.431 to -0.614n m/∘ realized for elbow and knee joint flexion between a range of motion around 0°-90°. Additionally, this sensor also displays high repeatability and stability and a fast response time of 1.4ms, combined with a small standard deviation of about 2.585%. The proposed sensor device possesses manufacturing simplicity, high processing accuracy, lightness, and elasticity, as well as certain improvements over other goniometers and optical fiber sensors. These attributes of the proposed sensor prove its applicability for human joint angle monitoring.

Highly Elastic and Anisotropic Wood-Derived Composite Scaffold with Antibacterial and Angiogenic Activities for Bone Repair.

Scaffold-based tissue engineering is a promising strategy to address the rapidly growing demand for bone implants, but developing scaffolds with bone extracellular matrix-like structures, suitable mechanical properties, and multiple biological activities remains a huge challenge. Here, it is aimed to develop a wood-derived composite scaffold with an anisotropic porous structure, high elasticity, and good antibacterial, osteogenic, and angiogenic activities. First, natural wood is treated with an alkaline solution to obtain a wood-derived scaffold with an oriented cellulose skeleton and high elasticity, which can not only simulate collagen fiber skeleton in bone tissue but also greatly improve the convenience of clinical implantation. Subsequently, chitosan quaternary ammonium salt (CQS) and dimethyloxalylglycine (DMOG) are further modified on the wood-derived elastic scaffold through a polydopamine layer. Among them, CQS endows the scaffold with good antibacterial activity, while DMOG significantly improves the scaffold's osteogenic and angiogenic activities. Interestingly, the mechanical characteristics of the scaffolds and the modified DMOG can synergistically enhance the expression of yes-associated protein/transcriptional co-activator with PDZ binding motif signaling pathway, thereby effectively promoting osteogenic differentiation. Therefore, this wood-derived composite scaffold is expected to have potential application in the treatment of bone defects.

3D Printing of Extracellular Matrix-Based Multicomponent, All-Natural, Highly Elastic, and Functional Materials toward Vascular Tissue Engineering.

3D printing offers an exciting opportunity to fabricate biological constructs with specific geometries, clinically relevant sizes, and functions for biomedical applications. However, successful application of 3D printing is limited by the narrow range of printable and bio-instructive materials. Multicomponent hydrogel bioinks present unique opportunities to create bio-instructive materials able to display high structural fidelity and fulfill the mechanical and functional requirements for in situ tissue engineering. Herein, 3D printable and perfusable multicomponent hydrogel constructs with high elasticity, self-recovery properties, excellent hydrodynamic performance, and improved bioactivity are reported. The materials' design strategy integrates fast gelation kinetics of sodium alginate (Alg), in situ crosslinking of tyramine-modified hyaluronic acid (HAT), and temperature-dependent self-assembly and biological functions of decellularized aorta (dAECM). Using extrusion-based printing approach, the capability to print the multicomponent hydrogel bioinks with high precision into a well-defined vascular constructs able to withstand flow and repetitive cyclic compressive loading, is demonstrated. Both in vitro and pre-clinical models are used to show the pro-angiogenic and anti-inflammatory properties of the multicomponent vascular constructs. This study presents a strategy to create new bioink whose functional properties are greater than the sum of their components and with potential applications in vascular tissue engineering and regenerative medicine.

Highly Elastic, Self-Healing, Recyclable Interlocking Double-Network Liquid-Free Ionic Conductive Elastomers via Facile Fabrication for Wearable Strain Sensors.

Liquid-free ionic conductive elastomers (ICEs) are ideal materials for wearable strain sensors in increasingly flexible electronic devices. However, developing recyclable ICEs with high elasticity, self-healability, and recyclability is still a great challenge. In this study, we fabricated a series of novel ICEs by in situ polymerization of lipoic acid (LA) in poly(acrylic acid) (PAA) solution and cross-linking by coordination bonding and hydrogen bonding. One of the obtained dynamically cross-linked interlocking double-network ICEs, PLA-PAA4-1% ICE, showed excellent mechanical properties, with high elasticity (90%) and stretchability (610%), as well as rapid self-healability (mechanical self-healing within 2 h and electrical recovery within 0.3 s). The PLA-PAA4-1% ICE was used as a strain sensor and possessed excellent linear sensitivity and highly cyclic stability, effectively monitoring diverse human motions with both stretched and compressed deformations. Notably, the PLA-PAA4-1% ICE can be fully recycled and reused as a new strain sensor without any structure change or degradation in performance. This work provided a viable path to fabricate conductive materials by solving the two contradictions of high mechanical property and self-healability, and structure stability and recyclability. We believe that the superior overall performance and feasible fabrication make the developed PLA-PAA4-1% ICE hold great promise as a multifunctional strain sensor for practical applications in flexible wearable electronic devices and humanoid robotics.

Do farmers pay for climate-resilient technology? Evidence from bidding experiments in eastern India

Using an experimental auction, we estimate demand for stress-tolerant rice varieties (STRVs) in eastern India, where frequent covariate production risks are affecting the welfare of smallholder farmers. STRVs have the potential to cope with low- to medium-intensity abiotic stresses and stabilize rice productivity in stress-prone rice ecosystems. The experiment involves a series of farmers’ decision-makings in the context of STRV seed purchase, set in an environment with minimal social frictions and improved information availability. Survival analysis, double hurdle, and sequential logit models are employed to understand farmers’ bidding and buying behavior. The results indicate that the demand for STRVs is highly elastic and is in line with reported market behavior. Willingness to pay (WTP) estimates for initial and latent buyers are coinciding, we find evidence of strategic underbidding by latent buyers in the experiment. Information asymmetry resulting from lack of awareness and previous experience in using STRVs is found to be the major reason for such decisions. Given the high elasticity of demand, STRV seed market distortion through subsidy, price cue, and an information campaign on variety characteristics and benefits could be an effective policy mix for overcoming the constraints related to price and asymmetric information and thereby increase adoption.

Evolution of flow reversal and flow heterogeneities in high elasticity wormlike micelles (WLMs) with a yield stress

The formation and evolution of a heterogeneous flow and flow reversal are examined in highly elastic, gel-like wormlike micelles (WLMs) formed from an amphiphilic triblock poloxamer P234 in 2M NaCl. A combination of linear viscoelastic, steady shear, and creep rheology demonstrate that these WLMs have a yield stress and exhibit viscoelastic aging, similar to some soft glassy materials. Nonlinear shear rheology and rheoparticle tracking velocimetry reveal that these poloxamer WLMs undergo a period of strong elastic recoil and flow reversal after the onset of shear startup. As flow reversal subsides, a fluidized high shear rate region and a nearly immobile low shear rate region of fluid form, accompanied by wall slip and elastic instabilities. The features of this flow heterogeneity are reminiscent of those for aging yield stress fluids, where the heterogeneous flow forms during the initial stress overshoot and is sensitive to the inherent stress gradient of the flow geometry. Additionally, macroscopic bands that form transiently above a critical shear rate become “trapped” due to viscoelastic aging in the nearly immobile region. This early onset of the heterogeneous flow during the rapidly decreasing portion of the stress overshoot differs from that typically observed in shear banding WLMs and is proposed to be necessary for observing significant flow reversal. Exploring the early-time, transient behavior of this WLM gel with rheology similar to both WLM solutions and soft glassy materials provides new insights into spatially heterogeneous flows in both of these complex fluids.

Conductive Hydrogel Patches with High Elasticity and Fatigue Resistance for Cardiac Microenvironment Remodeling.

Remodeling the conductive zone to assist normal myocardial contraction and relaxation during myocardial fibrosis has become the primary concern of myocardial infarction (MI) regeneration. Herein, we report an unbreakable and self-recoverable hyaluronic acid conductive cardiac patch for MI treatment, which can maintain structural integrity under mechanical load and integrate mechanical and electrical conduction and biological cues to restore cardiac electrical conduction and diastolic contraction function. Using the free carboxyl groups and aldehyde groups in the hydrogel system, excellent adhesion properties are achieved in the interface between the myocardial patch and the tissue, which can be closely integrated with the rabbit myocardial tissue, reducing the need for suture. Interestingly, the hydrogel patch exhibits sensitive conductivity (ΔR/R0 ≈ 2.5) for 100 cycles and mechanical stability for 500 continuous loading cycles without collapse, which allows the patch to withstand mechanical damage caused by sustained contraction and relaxation of the myocardial tissue. Moreover, considering the oxidative stress state caused by excessive ROS in the MI area, we incorporated Rg1 into the hydrogel to improve the abnormal myocardial microenvironment, which achieved more than 80% free radicalscavenging efficiency in the local infarcted region and promoted myocardial reconstruction. Overall, these Rg1-loaded conductive hydrogels with highly elastic fatigue resistance have great potential in restoring the abnormal electrical conduction pathway and promoting the myocardial microenvironment, thereby repairing the heart and improving the cardiac function.

Hierarchically interlocked helical conductive yarn enables ultra-stretchable electronics and smart fabrics

Simultaneously achieving high mechanical elasticity and electrical conductivity is essentially required for wearable electronics and smart fabrics. However, great challenges still remain to achieve high electrical conductance under large mechanical deformations due to the “trade-off” effect between them. Herein, inspired by curling structure of climbing plants, hierarchically interlocked helical conductive yarn for ultra-stretchable electronics and smart fabrics was developed, via over-twisting silver nanowires (AgNWs)/MXene multi-dimensional synergistic conductive networks that hierarchically entangled with elastic thermoplastic polyurethanes (TPU) nanofiber networks. High-aspect-ratio 1D AgNWs bridged 2D MXene nanosheets into synergistic interconnected conductive network while interlocked with elastic 3D TPU nanofiber skeleton. Unique hierarchically interlocking effect between highly conductive networks and highly elastic nanofiber networks during the twisting process induced helical conductive yarn simultaneously exhibits excellent mechanical stretchability and electrical conductivity. Excellent intrinsic elasticity of TPU macromolecular chains coupled with its hierarchically helical structure enables the conductive yarn exhibits excellent mechanical stretchability. While the hierarchically interlocked conductive structure ensures the stretchable yarn possess high electrical conductivity which could resist large mechanical deformations during stretching process. The hierarchically interlocked helical conductive yarn could still exhibit high electrical conductivity (1.12 × 105 S/m) even under large mechanical deformations (300%), which effectively avoid the “trade-off” effect. Moreover, the ultra-stretchable conductive yarn exhibits smart responsiveness to multi stimuli (mechanical/electron/light). The helical strain sensor has excellent electromechanical performance with stable GF (1.7) in the 600%–1000% linear range. The hierarchically interlocked helical conductive yarn holds great promise for ultra-stretchable electronics and smart fabrics.

Theory of low-temperature elasticity of amorphous polymers: Deformation at a constant rate and relaxation of deforming stress

The effect of temperature variations over a wide range on the rheological properties of amorphous polymers with high rubber-like elasticity (elastomers) is discussed. A theoretical study of the transition from the deformation state of a warm elastomer to the state of a frozen one, the effects of structural-strain glass transition and forced elasticity was done. Two types of mechanical testing of polymer samples are considered in detail: slow tensile deformation at a constant rate and relaxation of the deforming stress after deformation stops. The study was carried out on the basis of the previously proposed molecular-kinetic model of the processes of highly elastic deformation of amorphous polymers and the corresponding nonlinear rheological equation (V. D. Natsik and H. V. Rusakova, Fiz. Nizk. Temp. 48, 281 (2022) [Low Temp. Phys. 48, 253 (2022)]).

Construction of a myocardial patch with mesenchymal stem cells and poly(CL-co-TOSUO)/collagen scaffolds for myocardial infarction repair by coaxial electrospinning.

Stem cell cardiac patches have shown promising future for myocardium infarction (MI) therapy, but the characteristics of cardiac pulsation and tissue orientation lead to challenges in the design of cardiac repair scaffolds. Herein, a novel and multifunctional stem cell patch with favorable mechanical properties was reported. In this study, the scaffold was prepared by coaxial electrospinning of poly (CL-co-TOSUO)/collagen (PCT/collagen) core/shell nanofibers. Rat bone marrow-derived mesenchymal stem cells (MSCs) were seeded onto the scaffold to prepare the MSC patch. The nanofiber diameter of coaxial PCT/collagen was 945 ± 102 nm, and the tensile testing results showed that the PCT/collagen core/shell nanofibers possess highly elastic mechanical properties with an elongation at break higher than 300%. The results also showed that the MSCs maintained stem cell properties following seeding on the nano-fibers. The cells on the transplanted MSC patch survived 15 ± 4% 5 weeks following transplantation, and this PCT/collagen-MSC patch significantly improved the MI cardiac function and promoted angiogenesis. With high elasticity and good stem cell biocompatibility, the PCT/collagen core/shell nanofibers exhibited a good research value in the field of myocardial patches.

Hyaluronic Acid Filler Injection Technique in Multiple Layers of the Nasolabial Fold.

Sir: As mentioned by the author in his publication,1 to resolve the nasolabial fold (NLF), filler injection is most commonly used. In the study, fillers were injected in multiple layers of the NLF. However, we would like to discuss some complications associated with this technique. First, the facial artery is one of the largest arteries in the face and it runs near the NLF. Lee et al2 described variations in the course and depth of the facial artery and reported that more than 70% of the facial arteries were found at the NLF. The author of this article described injecting the filler at the supraperiosteal, deep and superficial fatty layers, and subdermal layer,1 but as seen in another study,2 filler injection in the deep and superficial fatty layers can be dangerous. Ultrasound shows that the facial artery can be detected at the NLF.3 In addition, it was found that 29% of the facial arteries run in the subcutaneous layer.3 Ultrasonographic image of the facial artery at the NLF area is shown in Figure 1. This means that filler injection in multiple layers is a very dangerous procedure as vascular injuries can occur, resulting in tragic complications such as skin necrosis.Fig. 1.: Doppler ultrasound image of facial artery located in the subcutaneous layer at the NLF.Second, the author did not mention the diameter of the cannula and compared to the puncturing needle, the cannula seemed to be smaller than 25 G. The outer diameter of a 25 G cannula is 0.51 mm, and the facial artery diameter is described to be 1.7–3.6 mm.4 This shows that a cannula can perforate the facial artery anytime, resulting in vascular complications. Clinicians should not be overly confident when using a cannula for injecting the filler. A recent article shows that a 27-G cannula can be as dangerous as a 27-G needle.5 Third, to describe specific fillers as being highly elastic or cohesive, rheological data should be provided. The author described Yvoire Y solution 720° as having high particle elasticity and stated that this is characteristic of a biphasic filler. However, he described Yvoire Y solution 540° as having low particle elasticity. As far as we know, Yvoire Y solution 540° also has characteristics of a biphasic filler. Usually, hyaluronic acid filler has rheological properties like high elastic modulus (characteristic of a biphasic filler) or high cohesiveness (characteristic of a monophasic filler). “High particle elasticity” was unclear when the nature of the filler was described. Furthermore, the particle size and rheological data of the filler used in the research were not provided. We would prefer it if hyaluronic acid was described as being volumizing at deep to mid-levels rather than having a high or low particle elasticity. Filler injection is a relatively easy esthetic procedure; nevertheless, surgeons must be aware of the possible vascular complications associated with this procedure. DISCLOSURE The authors have no financial interest to declare in relation to the content of this article.

Highly elastic and bioactive bone biomimetic scaffolds based on platelet lysate and biomineralized cellulose nanocrystals

Bone is a vascularized organic-inorganic composite tissue that shows a heavily-mineralized extracellular matrix (ECM) on the nanoscale. Herein, the nucleation of calcium phosphates during the biomineralization process was mimicked using negatively-charged cellulose nanocrystals (CNCs). These mineralized-CNCs were combined with platelet lysate to produce nanocomposite scaffolds through cryogelation to mimic bone ECM protein-mineral composite nature and take advantage of the bioactivity steaming from platelet-derived biomolecules. The nanocomposite scaffolds showed high microporosity (94–95%), high elasticity (recover from 75% strain cycles), injectability, and modulated platelet-derived growth factors sequestration and release. Furthermore, they increased alkaline phosphatase activity (up to 10-fold) and up-regulated the expression of bone-related markers (up to 2-fold), without osteogenic supplementation, demonstrating their osteoinductive properties. Also, the scaffolds promoted the chemotaxis of endothelial cells and enhanced the expression of endothelial markers, showing proangiogenic potential. These results suggest that the mineralized nanocomposite scaffolds can enhance bone regeneration by simultaneously promoting osteogenesis and angiogenesis.