Tunable Rheology Research Articles

Shearmetry of Fluids with Tunable Rheology by Polarized Luminescence of Rare Earth-Doped Nanorods.

Shear stress plays a critical role in regulating physiological processes within microcirculatory systems. While particle imaging velocimetry is a standard technique for quantifying shear flow, uncertainty near boundaries and low resolution remain severe restrictions. Additionally, shear stress determination is particularly challenging in biofluids due to their significant non-Newtonian behaviors. The present study develops a shearmetry technique in physiological settings using a biomimetic fluid containing rare earth-doped luminescent nanorods acting in two roles. First, they are used as colloidal additives adjusting rheological properties in physiological media. Their anisotropic morphology and interparticle interaction synergistically induce a non-Newtonian shear-thinning effect emulating real biofluids. Second, they can probe shear stress due to the shear-induced alignment. The polarized luminescence of the nanorods allows for quantifying their orientational order parameter and thus correlated shear stress. Using scanning confocal microscopy, we demonstrate the tomographic mapping of the shear stress distribution in microfluidics. High shear stress is evident near the constriction and the cellular periphery, in which non-Newtonian effects can have a significant impact. This emerging shearmetry technique is promising for implementation in physiological and rheological environments of biofluids.

Luminescent Supramolecular Metallogels: Drug Loading and Eu(III) as Structural Probe.

Supramolecular metallogels combine the rheological properties of gels with the color, magnetism, and other properties of metal ions. Lanthanide ions such as Eu(III) can be valuable components of metallogels due to their fascinating luminescence. In this work, we combine Eu(III) and iminodiacetic acid (IDA) into luminescent hydrogels. We investigate the tailoring of the rheological properties of these gels by changes in their metal:ligand ratio. Further, we use the highly sensitive Eu(III) luminescence to obtain information about the chemical structure of the materials. In special, we take advantage of computational calculations to employ an indirect method for structural elucidation, in which the simulated luminescent properties of candidate structures are matched to the experimental data. With this strategy, we can propose molecular structures for different EuIDA gels. We also explore the usage of these gels for the loading of bioactive molecules such as OXA, observing that its aldose reductase activity remains present in the gel. We envision that the findings from this work could inspire the development of luminescent hydrogels with tunable rheology for applications such as 3D printing and imaging-guided drug delivery platforms. Finally, Eu(III) emission-based structural elucidation could be a powerful tool in the characterization of advanced materials.

A Review on Formulation, Characterization and Applications of Nanoemulsion

This review discusses the development, manufacturing, fabrication, and manipulation of Nanoemulsions, an advanced drug delivery method that addresses the limitations of conventional systems. Nanoemulsions are biphasic dispersions of immiscible liquids, either water in oil or oil in water, stabilized by an amphiphilic surfactant. They offer various drug delivery functionalities but face challenges in stability, structure control, and characterization. Nanoemulsions, with droplet sizes of 100 nm, are kinetically stable liquid-in-liquid dispersions with high surface area, robust stability, optical transparency, and tunable rheology. These submicron-sized emulsions are being studied for drug delivery and targeting, offering potential in cosmetics, diagnostics, drug therapies, and biotechnologies. They are used in cancer treatment, drug targeting, mucosal vaccines, transdermal drug delivery, lipophilic drugs, and self-nanoemulsifying drug delivery systems. This review explores various techniques for developing and characterizing Nanoemulsions, their formation and stability theories, and their current and future applications due to their unique structures and chemistries. This review discusses the importance of optimal formulation for nano-droplet systems, focusing on droplet size, solubilization, colloidal stability, optical and rheological properties. This research focuses on the study of various techniques of preparing Nanoemulsions i.e., high energy methods and low energy methods. This study explores the best methods for formulating Nanoemulsions, their characterization, release kinetics, and application in various fields.

A Printable Magnetic-Responsive Iron Oxide Nanoparticle (ION)-Gelatin Methacryloyl (GelMA) Ink for Soft Bioactuator/Robot Applications.

The features or actuation behaviors of nature's creatures provide concepts for the development of biomimetic soft bioactuators/robots with stimuli-responsive capabilities, design convenience, and environmental adaptivity in various fields. Mimosa pudica is a mechanically responsive plant that can convert pressure to the motion of leaves. When the leaves receive pressure, the occurrence of asymmetric turgor in the extensor and flexor sides of the pulvinus from redistributing the water in the pulvinus causes the bending of the pulvinus. Inspired by the actuation of Mimosa pudica, designing soft bioactuators can convert external stimulations to driving forces for the actuation of constructs which has been receiving increased attention and has potential applications in many fields. 4D printing technology has emerged as a new strategy for creating versatile soft bioactuators/robots by integrating printing technologies with stimuli-responsive materials. In this study, we developed a hybrid ink by combining gelatin methacryloyl (GelMA) polymers with iron oxide nanoparticles (IONs). This hybrid ION-GelMA ink exhibits tunable rheology, controllable mechanical properties, magnetic-responsive behaviors, and printability by integrating the internal metal ion-polymeric chain interactions and photo-crosslinking chemistries. This design offers the inks a dual crosslink mechanism combining the advantages of photocrosslinking and ionic crosslinking to rapidly form the construct within 60 s of UV exposure time. In addition, the magnetic-responsive actuation of ION-GelMA constructs can be regulated by different ION concentrations (0-10%). Furthermore, we used the ION-GelMA inks to fabricate a Mimosa pudica-like soft bioactuator through a mold casting method and a direct-ink-writing (DIW) printing technology. Obviously, the pinnule leaf structure of printed constructs presents a continuous reversible shape transformation in an air phase without any liquid as a medium, which can mimic the motion characteristics of natural creatures. At the same time, compared to the model casting process, the DIW printed bioactuators show a more refined and biomimetic transformation shape that closely resembles the movement of the pinnule leaf of Mimosa pudica in response to stimulation. Overall, this study indicates the proof of concept and the potential prospect of magnetic-responsive ION-GelMA inks for the rapid prototyping of biomimetic soft bioactuators/robots with untethered non-contact magneto-actuations.

Strongly adhesive zwitterionic composite hydrogel paints for surgical sutures and blood-contacting devices.

Hydrogels show eminent advantages in biomedical and pharmaceutical fields. However, their application as coating materials for biomedical devices is limited by several key challenges, such as lack of universality, weak mechanical strength, and low adhesion to the substrate. Here we report versatile and tough adhesion composite hydrogel paints (CHPs), which consist of zwitterionic copolymers and microgels, both with reactive groups. The CHPs exhibit tunable rheology and thickness, hydrophilicity, biofouling resistance, durability, and convenient fabrication on metal, polymer, and inorganic surfaces with arbitrary shapes. As a proof-of-concept, the CHP-surgical sutures demonstrate exceptional lubrication, drug delivery, anti-infection, and anti-fibrous capsule properties. Moreover, the CHP-PVC tubing effectively prevents thrombus formation in vitro and ex vivo rabbit blood circulation without anticoagulants. This work provides valuable insights for enhancing and developing integrated hydrogel technologies for biomedical devices. STATEMENT OF SIGNIFICANCE: The combination of hydrogel and biomedical devices can enable numerous existing applications in medicine. In this study, inspired by the principle of microgel reinforcement in industrial paints, we propose a simple and versatile zwitterionic composite hydrogel paints (CHPs) strategy, which can be easily applied to diverse substrates with arbitrary shapes by covalent grafting between complementary groups by brush, dip, or spray. The CHPs integrated universality, tough adhesion, mechanical durability, and anti-biofouling properties because of their unique chemical composition and coating structure design. This strategy provides a simple and versatile route for surface modification of biomedical devices.

Rheological study of nanoemulsions with repulsive and attractive interdroplet interactions.

Nanoemulsions have adjustable transparency, tunable rheology, high stability, and low sensitivity to changes in pH and temperature, which make them interesting for applications such as low-fat and low-calorie foods. In this research, we study model concentrated nanoemulsions which are stabilized by sodium dodecyl sulfate (SDS). To prepare samples in different structural states, semi-dilute nanoemulsions are prepared at 25% droplet volume fraction (φ), after which evaporating the continuous phase at room temperature leads to concentrated nanoemulsions up to 60% volume fraction. Surfactant concentration is also tuned to induce different interdroplet interactions so that concentrated nanoemulsions in repulsive glass, attractive glass, and gel states are achieved. Rheological properties of nanoemulsions with different structural states are comprehensively studied over a volume fraction range. Utilizing the existing predictive models for (nano)emulsion rheology reveals a more satisfactory prediction for repulsive systems than systems with attractive interactions. In addition, a master curve is constructed for storage and loss moduli of nanoemulsions with different interdroplet interactions. The present work offers control over physicochemical properties of nanoemulsions for design of new food products with enhanced quality and functionality.

Electrochemical investigation of fluorine-containing Li-salts as slurry cathode additives for tunable rheology in super high solid content NMP slurries

Fluorine-containing Li-salts are used as slurry cathode additives for tunable rheology in super high solid content slurries for the first time.

Localized delivery of FTY-720 from 3D printed cell-laden gelatin/silk fibroin composite scaffolds for enhanced vascularized bone regeneration

Three-dimensional (3D) printing can construct products with accurate complex architecture. Engineered bone tissues that can promote vascularization and regulate directed differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) are considered as an ideal substitute the healing of bone for bone defects treatment. Herein, we fabricated a 3D printed BMSCs-laden scaffold using methacrylated gelatin and methacrylated silk fibroin (GelMA/SFMA) based bioinks along with localized sustained release of a small molecule drug fingolimod (FTY-720) for the synergistic interactions of vascularization and osteogenesis during bone repair. The GelMA/SFMA bioink showed significant advantages due to their tunable rheology, rapid thermal crosslinking, and improved shape fidelity following bioprinting. The in vitro experiments demonstrated that high cell viability of cells-laden constructs, while FTY-720-containing scaffolds significantly promoted migration and induced tube-like structure formation of human umbilical vein endothelial cells (HUVECs) as well as expressed high osteogenic-related genes expression of BMSCs. The implantation in a critical-size rat cranial defect model further revealed that FTY-720-loaded scaffolds significantly promoted vascularization and bone regeneration. Furthermore, scaffolds carrying BMSCs and FTY-720 were more osteogenic in vivo than scaffolds carrying BMSCs alone. Therefore, the constructed BMSCs-laden and FTY-720-loaded GelMA/SFMA scaffolds would be an ideal candidate with required structure and desired function for vascularization of bone regeneration.

An Electromechanical <i>In Situ</i> Viscosity Measurement Technique for Shear Thickening Fluids

This paper presents the feasibility of developing an electromechanical in-situ viscosity measurement technique by analyzing the detectability of small variations in the viscosity of different shear thickening fluids and their different compositions. Shear thickening fluid (STF) is a kind of non-Newtonian fluid showing an increasing viscosity profile under loading. STF is utilized in several applications to take advantage of its tunable rheology. However, process control in different STF applications requires rheological measurements, which cause a costly investment and long-lasting labor. Therefore, one of the most commonly used in-situ structural health monitoring techniques, electromechanical impedance (EMI), was used in this study. In order to actuate the medium electromechanically, a piezoelectric wafer active sensor (PWAS) was used. The variations in the spectral response of PWAS resonator that can be submerged into shear thickening fluid are analyzed by the root mean square deviation, mean absolute percentage deviation and correlation coefficient deviation. According to the results, EMI metrics provide good correlations with the rheological parameters of STF and thereby enabling quick and low-cost rheological control for STF applications such as vibration dampers or stiffness control systems.

Preparation and evaluation of a novel high internal phase Pickering emulsion based on whey protein isolate nanofibrils derived by hydrothermal method

The present work aimed to explore nanofibrils prepared from whey protein isolate (WPNFs) by hydrothermal to stabilize high internal phase Pickering emulsion (HIPPEs). WPNFs with well-ordered β-sheet structures and high aspect ratio were efficiently prepared by hydrothermal at 110 °C for 4 h, which is more efficiently than conventional method at 80–90 °C for 5–24 h. The characteristics of the building blocks analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with Tris-Tricine buffer system and liquid chromatography linked to tandem mass spectrometry (LC-MS/MS) proved that the formation of WPNFs is based on the hydrolysis of WPI, and hydrothermal can make WPI hydrolysis faster and more efficiently. The high internal phase Pickering emulsion (HIPPEs) stabilized by 5 wt% of WPNFs (internal phase fraction Φ up to 0.90) showed an excellent stability. The microstructure of HIPPEs illustrated by super resolution microscope and cryo-scanning electron microscopy showed that WPNFs tightly wrapped the oil droplets forming an ordered viscoelastic and dense interface layer. It can be speculated that WPNFs were flexible due to their large aspect ratio and mechanical strength, which allowed them to bend on the surface of the droplet to form a better package protection. Rheology and texture analysis showed that WPNFs stabilized HIPPEs have solid-like and tunable rheological properties. WPNFs were verified to improve the oil binding capacity and antioxidant activity. The results provided that hydrothermal is a novel and efficient method for preparing WPNFs, and the prepared WPNFs can be used to stabilize HIPPEs with tunable rheology.

An injectable, dual crosslinkable hybrid pectin methacrylate (PECMA)/gelatin methacryloyl (GelMA) hydrogel for skin hemostasis applications

Biomaterials for effective hemorrhage control are urgently needed in clinics as uncontrolled bleeding is associated with high mortality. Herein, we developed an injectable and in situ photo-crosslinkable hybrid hemostatic hydrogel by combining pectin methacrylate (PECMA) and gelatin methacryloyl (GelMA). This modular material system combines ionic- and photo-crosslinking chemistries to design interpenetrating networks (IPN) exhibiting tunable rheology, highly porous structure, and controllable swelling and mechanical properties. By simply changing the calcium (0–15 mM) and polymer (1.5–7%) content used for the sequential crosslinking of hydrogels via calcium gelation and UV-photopolymerization, it was possible to precisely modulate the injectability, degradation, and swelling ratio. Moreover, it is demonstrated that PECMA/GelMA hydrogels present good cytocompatibility and uniquely synergize the hemostatic properties of calcium ions on PECMA, the amine residues on GelMA, and the highly porous network toward rapid blood absorption and fast coagulation effect. An in vitro porcine skin bleeding model confirmed that the hydrogel could be directly injected into the wound and rapidly photo-crosslinked, circumventing the bleeding and decreasing the coagulation time by 39%. Importantly, the crosslinked hydrogel could be easily removed to prevent secondary wound injury. Overall, this injectable hybrid PECMA/GelMA hydrogel stands as a promising hemostatic material.

Ultrasound-assisted synthesis and characterization of sesame oil based nanoemulsion

Nanoemulsions are emulsions having droplet sizes in the nanometre range. Nano emulsions have unique properties such as robust stability, transparent nature, high surface area, and tunable rheology. The present study focuses on the synthesis of sesame oil-based nanoemulsion using ultrasonic emulsification to break down particle size to nanometric range. The method uses small surfactant concentration and low energy to synthesize homogenous nanoemulsion. The emulsion is stabilized using Tween 20 surfactant. Aqueous nanoemulsion samples were prepared using sesame oil by varying the surfactant concentration to determine the most stable composition, and different properties of each sample prepared, were analyzed. The ultrasonication time was also varied to study the impact of sonication time. Nanoemulsions formed were then evaluated for their various properties. The droplet size and zeta potential for all samples were determined by the Dynamic Light Scattering technique wherein the best nanometer size distribution was found to be at 1:3 (oil: surfactant) composition. The physical stability was determined using a centrifuge at 3000 rpm. Conductivity, pH, and density of the samples were then measured. A polydispersity index of 0.514 was obtained for the sample of oil: surfactant ratio 1:3. Fourier Transform Infrared Spectroscopy studies were conducted for all samples.

Associative structures formed from cellulose nanofibrils and nanochitins are pH-responsive and exhibit tunable rheology

HypothesisNanocellulose and nanochitin are both biobased materials with complementary structures and properties. Both exhibit pH-dependent surface charges which are opposite in sign. Hence, it should be possible to manipulate them to form complexed structures via ionic bond formation at prescribed pH conditions. ExperimentNanocellulose and nanochitin were mixed after exposure to acidic or neutral conditions to influence their ionization state. The heat of interaction during the introduction of nanochitin to nanocellulose was monitored via isothermal titration calorimetry. The strength and gel properties of the resulting structures were characterized via rheological measurement. FindingsThe resultant gel properties in the designed hybrid systems were found to depend directly on the charge state of the starting materials, which was dictated by pH adjustment. Different interparticle interactions including ionic attraction, hydrophobic associations, and physical entanglement were identified in the systems and the influence of each was elucidated for different conditions of pH, concentration, and ratio of nanochitin to nanocellulose. Hydrophobic associations between neutralized nanochitin particles were found to contribute strongly to increased elastic modulus values. Ionic complex formation was found to provide enhanced stability under broader pH conditions, while physical entanglement of cellulose nanofibers was a substantial thickening mechanism in all systems.

Understanding the Molecular Structure of the Elastic and Thermoreversible AlCl3 : Urea/Polyethylene Oxide Gel Electrolyte.

It is possible to prepare elastic and thermoreversible gel electrolytes with significant electroactivity by dissolving minimal weight fractions of ultra-high molecular weight polyethylene oxide (UHMW PEO) in an aluminum deep eutectic solvent (DES) electrolyte composed of AlCl3 and urea at a molar ratio of 1.5 : 1 (AlCl3 /urea). The experimental vibrational spectra (FTIR and Raman) provide valuable information on the structure and composition of the gel electrolyte. However, the complexity of this system requires computational simulations to help interpretation of the experimental results. This combined approach allows us to elucidate the speciation of the DES liquid electrolyte in the gel and how it interacts with the polymer chains to give rise to an elastic network that retains the electroactivity of the liquid electrolyte to a very great extent. The observed reactions occur between the ether in the polymer and both the amine groups in urea and the aluminum species. Thus, similar elastomeric gels may likely be prepared with other aluminum liquid electrolytes, making this procedure an effective way to produce families of gel aluminum electrolytes with tunable rheology and electroactivity.

Transparent model concrete with tunable rheology for investigating flow and particle-migration during transport in pipes

The article describes the adaption and properties of a model concrete for detailed flow studies. To adapt the yield stress and plastic viscosity of the model concrete to the corresponding rheological properties of real concrete, the model concrete is made of a mixture of glass beads and a non-Newtonian fluid. The refractive index of the non-Newtonian fluid is adjusted to the refractive index of the glass beads by the addition of a further constituent. The rheological properties of the model concrete are characterised by measurements in concrete rheometers. Finally, the first exemplary results from experiments with the model concrete are presented, which give incipient impressions of the complex internal dynamics in flowing concrete.

Montmorillonite and alginate co-stabilized biocompatible Pickering emulsions with multiple-stimulus tunable rheology

A biocompatible oil-in-water emulsion containing no surfactant or other organic modifier was prepared using two negatively charged, naturally derived materials: alginate and montmorillonite (MMT), and it was found that the stable emulsion has good storage stability and coalescence stability. The dispersing and suspending effects of alginate to MMT were observed, and the interaction between alginate and MMT was confirmed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Zeta potential. The distribution of particles at the oil-water interface and in the aqueous phase of the emulsion was observed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). A unique mechanism of the stable Pickering emulsion was then proposed. It is demonstrated that alginate not only thicken the continuous phase, create a gel-like environment around the droplets, but also could modify the MMT surface, synergistically enhance the electrostatic force of droplets due to the same charge property with MMT. Moreover, the rheological properties of the emulsion co-stabilized by MMT/Alginate can be well adjusted using various stimuli including pH and salt. In general, this work presents a highly stable, tunable and biocompatible emulsion for potential applications in food and cosmetic products.

Scalable Fabrication of High-Performance Transparent Conductors Using Graphene Oxide-Stabilized Single-Walled Carbon Nanotube Inks.

Recent development in liquid-phase processing of single-walled carbon nanotubes (SWNTs) has revealed rod-coating as a promising approach for large-scale production of SWNT-based transparent conductors. Of great importance in the ink formulation is the stabilizer having excellent dispersion stability, environmental friendly and tunable rheology in the liquid state, and also can be readily removed to enhance electrical conductivity and mechanical stability. Herein we demonstrate the promise of graphene oxide (GO) as a synergistic stabilizer for SWNTs in water. SWNTs dispersed in GO is formulated into inks with homogeneous nanotube distribution, good wetting and rheological properties, and compatible with industrial rod coating practice. Microwave treatment of rod-coated films can reduce GOs and enhance electro-optical performance. The resultant films offer a sheet resistance of ~80 Ω/sq at 86% transparency, along with good mechanical flexibility. Doping the films with nitric acid can further decrease the sheet resistance to ~25 Ω/sq. Comparing with the films fabricated from typical surfactant-based SWNT inks, our films offer superior adhesion as assessed by the Scotch tape test. This study provides new insight into the selection of suitable stabilizers for functional SWNT inks with strong potential for printed electronics.

Structural Design and Physicochemical Foundations of Hydrogels for Biomedical Applications.

Biomedical research, known as medical research, is conducive to support and promote the development of knowledge in the field of medicine. Hydrogels have been extensively used in many biomedical fields due to their highly absorbent and flexible properties. The smart hydrogels, especially, can respond to a broad range of external stimuli such as temperature, pH value, light, electric and magnetic fields. With excellent biocompatibility, tunable rheology, mechanical properties, porosity, and hydrated molecular structure, hydrogels are considered as promising candidate for simulating local tissue microenvironment. In this review article, we mainly focused on the most recent development of engineering synthetic hydrogels; moreover, the classification, properties, especially the biomedical applications including tissue engineering and cell scaffolding, drug and gene delivery, immunotherapies and vaccines, are summarized and discussed.

3D Bioprinting of Low-Concentration Cell-Laden Gelatin Methacrylate (GelMA) Bioinks with a Two-Step Cross-linking Strategy.

Methacrylated gelatin (GelMA) has been widely used as a tissue-engineered scaffold material, but only low-concentration GelMA hydrogels were found to be promising cell-laden bioinks with excellent cell viability. In this work, we reported a strategy for precise deposition of 5% (w/v) cell-laden GelMA bioinks into controlled microarchitectures with high cell viability using extrusion-based three-dimensional (3D) bioprinting. By adding gelatin into GelMA bioinks, a two-step cross-linking combining the rapid and reversible thermo-cross-linking of gelatin with irreversible photo-cross-linking of GelMA was achieved. The GelMA/gelatin bioinks showed significant advantages in processability because the tunable rheology and the rapid thermo-cross-linking of bioinks improved the shape fidelity after bioprinting. Here, the rheology, mechanical properties, and swelling of GelMA/gelatin bioinks with different concentration ratios were carefully characterized to obtain the optimized bioprinting setup. We successfully printed the 5% (w/v) GelMA with 8% (w/v) gelatin into 3D structures, which had the similar geometrical resolution as that of the structures printed by 30% (w/v) GelMA bioinks. Moreover, the cell viability of 5/8% (w/v) GelMA/gelatin bioinks was demonstrated by in vitro culture and cell printing of bone marrow stem cells (BMSCs). Larger BMSC spreading area was found on 5/8% (w/v) GelMA/gelatin scaffolds, and the BMSC viability after the printing of 5/8% (w/v) GelMA/gelatin cell-laden bioinks was more than 90%, which was very close to the viability of printing pure 5% (w/v) GelMA cell-laden bioinks. Therefore, this printing strategy of GelMA/gelatin bioinks may extensively extend the applications of GelMA hydrogels for tissue engineering, organ printing, or drug delivery.

Hydrogel Nanocomposites with Independently Tunable Rheology and Mechanics.

Hydrogels are an attractive class of biomaterials for minimally invasive local drug delivery given their injectability, tunability, high water content, and biocompatibility. Broad applicability though is challenged: relatively modest mechanical properties restrict use to soft tissues, while flow properties necessary for injectability limit implantation to dried, enclosed tissues to minimize material migration during gelation. To address these dual concerns, we designed an injectable nanocomposite hydrogel based on dextran aldehyde and a poly(amido amine) dendrimer doped with phyllosilicate nanoplatelet fillers. Balance of components allows for exfoliation of nanoplatelets, significantly changing macromer solution flow, facilitating injection and manipulation in a wide variety of implantation contexts while enhancing compressive modulus of hydrogels at low loading. Importantly, rheological and mechanical effects were dependent on aspect ratio, with high aspect ratio nanoplatelets having much stronger effects on mechanics and low aspect ratio nanoplatelets having stronger effects on rheology, enabling nearly independent control of rheological and mechanical properties. Nanoplatelets enhanced hydrogel properties at a filler loading substantially lower than that of comparably sized nanoparticles. We present a model to explain the role that aspect ratio plays in control of rheology and mechanics in nanoplatelet-containing hydrogels, with lessons for further nanocomposite hydrogel development. This low-cost biocompatible material may be useful as a drug delivery platform in challenging implantation environments.