Shape Transformation Research Articles

From Sea Cucumbers to Soft Robots: A Photothermal-Responsive Hydrogel Actuator with Shape Memory.

Soft robotics has undergone considerable progress driven by materials that can effectively transduce external stimuli into mechanical actuation. Here, we report the development of a photothermal-responsive hydrogel actuator with shape memory capabilities inspired by the adaptive locomotion of sea cucumbers. This actuator is based on sea cucumber peptides (SCP) and a liquid metal (LM) hydrogel network that is responsive to near-infrared (NIR) light. Upon NIR irradiation, the hydrogel undergoes a phase transition from a swollen to a collapsed state, resulting in a controlled volumetric and shape change. Incorporating a shape memory polymer (SMP) into the hydrogel matrix facilitates the actuator's retention of its deformed configuration following stimulus removal, thereby enabling intricate, multiphase shape transformations. This SCP/LM hydrogel overcomes the limitations of traditional hydrogels and achieves good stretchability (3,000%) and enough adhesion (21 kPa), exhibiting no toxicity to human cells. Furthermore, the actuator exhibited significant bending and complex deformation within 100 s of NIR exposure. This photothermal-responsive hydrogel actuator offers new opportunities for soft robotics and biomedical applications, showcasing a potential pathway for incorporating shape memory and photothermal-responsive materials into the next generation of smart soft devices.

Stiffness Tunable Magnetic Actuators Based on Shape Memory Polymer/NdFeB Composite for Segmental Controllable Motion.

Soft magnetic robots have attracted extensive research interest recently due to their fast-transforming ability and programmability. Although the inherent softness of the matrix materials enables dexterity and safe interactions, the contradiction between the easy shape transformation of the soft matrices and load carrying capacity, as well as the difficulty of independently controllable motion of individual segments, severely limits its design space and application potentials. Herein, we have proposed a strategy to adjust the modulus of shape memory polymer composite embedded with hard magnetic particles by in situ Joule heating of printed circuit, which can reversibly change the stiffness from 4.1 GPa at 25°C to 10.9 MPa at 70°C. The stiffness tunable magnetic robots realize the compatibility of fast reversible shape transformation and high load carrying capacity. Furthermore, multiple separated Joule circuits are designed for the independently controllable motion of individual segments. The simulation of Joule heating and magnetic actuation is used to guide the design of devices. The concept of simultaneously programming magnetic anisotropy and stiffness proposed in this work greatly expands the design space and new applications of magnetic actuators, including soft grippers for heavy loads and bionic hand with independent motion of fingers.

Programmed shape transformations in cell-laden granular composites.

Tissues form during development through mechanical compaction of their extracellular matrix (ECM) and shape morphing, processes that result in complex-shaped structures that contribute to tissue function. While observed in vivo, control over these processes in vitro to understand both tissue development and guide tissue formation has remained challenging. Here, we use combinations of mesenchymal stromal cell spheroids and hydrogel microparticles (microgels) with varied hydrolytic stability to fabricate programmable and dynamic granular composites that control compaction and tissue formation over time. Mixed microgel populations of varying stability provide a further handle to alter compaction, and the level of compaction guides the uniformity and level of ECM deposition within tissues. Last, spatially patterned granular composites of varying compaction enable shape transformations (i.e., bending/curvature) that are stable with culture and are predicted by finite element models.

Hot shape transformation: the role of PSar dehydration in stomatocyte morphogenesis.

Polysarcosine emerges as a promising alternative to polyethylene glycol (PEG) in biomedical applications, boasting advantages in biocompatibility and degradability. While the self-assembly behavior of block copolymers containing polysarcosine-containing polymers has been reported, their potential for shape transformation remains largely untapped, limiting their versatility across various applications. In this study, we present a comprehensive methodology for synthesizing, self-assembling, and transforming polysarcosine-poly(benzyl glutamate) block copolymers, resulting in the formation of bowl-shaped vesicles, disks, and stomatocytes. Under ambient conditions, the shape transformation is restricted to bowl-shaped vesicles due to the membrane's flexibility and permeability. However, dehydration of the polysarcosine broadens the possibilities for shape transformation. These novel structures exhibit asymmetry and possess the capability to encapsulate smaller structures, thereby broadening their potential applications in drug delivery and nanotechnology. Our findings shed light on the unique capabilities of polysarcosine-based polymers, paving the way for further exploration and harnessing of their distinctive properties in biomedical research.

Stable nanobubbles on ordered water monolayer near ionic model surfaces

Abstract The stable nanobubbles adhered to mineral surfaces may facilitate their efficient separation via flotation in the mining industry. However, the state of nanobubbles on mineral solid surfaces is still elusive. In this study, molecular dynamics (MD) simulations are employed to examine mineral-like model surfaces with varying degrees of hydrophobicity, modulated by surface charges, to elucidate the adsorption behavior of nanobubbles at the interface. Our findings not only contribute to the fundamental understanding of nanobubbles but also have potential applications in the mining industry. We observed that as the surface charge increases, the contact angle of the nanobubbles increases accordingly with shape transformation from a pancake-like gas film to a cap-like shape, and ultimately forming a stable nanobubble upon an ordered water monolayer. When the solid–water interactions are weak with a small partial charge, the hydrophobic gas (N2) molecules accumulate near the solid surfaces. However, we have found, for the first time, that gas molecules assemble a nanobubble on the water monolayer adjacent to the solid surfaces with large partial charges. Such phenomena are attributed to the formation of a hydrophobic water monolayer with a hydrogen bond network structure near the surface.

Electro-thermal responses polymer systems with continuous shape memory alloys: Merging rapid shape memory and color transitions

Multi-responsive shape memory materials with on-demand programmability via external stimuli are highly desirable for many modern technologies-based applications, but have yet to be mixed with color-changing materials through a 3D-printing approach. To address this challenge, we engineered a blend of polylactic acid (PLA) and polyurethane (TPU), incorporated with thermochromic microcapsules (TMC), and fused these components through melt extrusion to create a 3D-printable, ternary filament. When combined with a shape memory alloy (SMA) wire using continuous fiber-reinforced 3D printing techniques, it gives rise to a PLA/TPU/TMC@SMA composite with exceptional conductivity, intelligent 3D structural adaptability, and superior mechanical characteristics, i.e., 3.29 % elongation at break and a 19.05 MPa tensile strength. Notably, our printed composite strip exhibits outstanding reversibility in electrochromic chromaticity parameters, swiftly recovering to its initial state after electrochromic heating and rapid cooling cycles, thus providing real-time reversible electrochromic responses. Furthermore, our composite strip displays rapid and simultaneous shape and color transformations upon exposure to predefined temperature thresholds, highlighting its dynamic functionality. Incorporating a highly efficient conductive network of continuous SMA wires enables swift electric and thermal shape memory responses, making our PLA/TPU/TMC@SMA composite an ideal candidate for high-performance electro-thermal actuators across diverse applications.

Shape-controlled Bose–Einstein condensation

Abstract Size-invariant shape transformation is a geometric technique that allows for a clear separation between quantum size and shape effects by modifying the shape of the confinement domain without altering its size. The impact of shape on the behavior of confined systems is significantly different from that of size, making it an emerging area of research. The recent realization of flat-bottomed optical box traps has further contributed to the study of quantum gases in complex confinement geometries. Here, we propose shape-induced Bose–Einstein condensation at a fixed size, temperature, and density. We investigate the impact of pure quantum shape effects on a non-interacting Bose gas confined within nested square domains, where the shape parameter is defined and controlled by the rotation angle between the inner and outer squares. Our findings reveal that specific heat exhibits an additional low-temperature peak at certain shapes. This work opens new avenues for controlling quantum systems through geometric manipulation and provides insights into the thermodynamic properties of Bose gases under shape-induced quantum effects.

Educational Development through the Lens of Curriculum: A Holistic and Systemic Approach

As an expert in educational sciences and a Full Professor in the Department of Teaching at UQAM, I bring to this discussion my experience in curriculum development, bolstered by my role as co-holder of the UNESCO Chair in Curriculum Development and Senior Fellow at UNESCO’s International Bureau of Education. Inspired by IBE-UNESCO’s educational philosophy, I emphasize the curriculum as a central element in advancing educational development. In this presentation, I position the curriculum not merely as a framework for what students learn but as a dynamic and influential instrument for shaping societal growth and transformation. The holistic and systemic approach I propose in this presentation highlights the interconnected nature of curriculum elements, extending from individual well-being to the cultivation of interdisciplinary knowledge. This approach is explored through seven key themes, each incorporating insights from educational philosophy, pedagogy, and policy, revealing the transformative potential of a well-constructed curriculum. These seven themes reveal the curriculum’s role in shaping both individuals and society. It reflects societal values, supports well-being and personal growth, and requires a systemic approach to reform. Through integrated pedagogy, it develops both disciplinary and global competencies, while interdisciplinary perspectives allow students to address complex issues. Evaluation aligns learning with progress, and adaptability ensures relevance in a changing world. For each theme, I found it valuable to highlight two foundational references that deepen our understanding. Together, these dimensions create a curriculum that empowers learners and drives societal growth

Impact of Vascular Endothelial Growth Factor on the Shape, Survival, and Osteogenic Transformation of Gingiva-Derived Stem Cell Spheroids.

Background and Objectives: Vascular endothelial growth factor (VEGF) is a protein which stimulates the formation of new blood vessels, playing a crucial role in processes such as wound healing and tumor growth. Methods: This study investigated the effects of VEGF on cell viability and osteogenic differentiation in mesenchymal stem cell (MSC) spheroids. Stem cell spheroids were fabricated using concave microwells and cultured with VEGF at concentrations of 0, 0.01, 0.1, 1, and 10 ng/mL. Morphological assessments were conducted on days 1, 3, 5, and 7, while cell viability was evaluated using the LIVE/DEAD assay and Cell Counting Kit-8. Alkaline phosphatase activity (ALP) and calcium deposition were measured to assess osteogenic differentiation, and qPCR was used to analyze osteogenic marker expression. Results: The spheroids maintained their shape across all VEGF concentrations, with the largest diameter being at 0.01 ng/mL on day 1, which decreased over time. Cell viability was highest at 0.01 ng/mL VEGF, while calcium deposition peaked at 0.1 ng/mL. Osteogenic markers, including RUNX2, osteocalcin, and COL1A1, showed significant upregulation at 1 ng/mL VEGF. Conclusions: These results suggest that VEGF enhances early osteogenic differentiation in MSC spheroids, indicating its potential for bone repair and tissue regeneration. VEGF could be applied in clinical settings for bone healing, fracture repair, and regenerative dentistry treatments.

A One-Stone-Two-Birds Strategy for Photothermal Shape Memory Polyurethane Utilizing Lignin as Monomer and Internal Photothermal Agent.

Photothermal-triggering shape memory polyurethane allows for precise and controllable shape transformation under remote light stimulation, making it highly desirable for applications in intelligent devices. This study develops a sustainable and high-performance lignin-based polyurethane (LPU) using a one-stone-two-birds strategy, wherein lignin serves as both a synthetic monomer and an internal photothermal agent. The incorporation of lignin significantly improved the mechanical properties of LPU, achieving a tensile strength of 42.1MPa and an impressive elongation at break of 1558%. Additionally, the LPU exhibited exceptional photothermal heating capabilities due to the inherent intramolecular π-π conjugations and intermolecular π-π stacking effects of lignin, which facilitated the precise and contactless remote photoheating. Furthermore, the rigid structure of lignin and robust hydrogen bonding interactions provided LPU with excellent multi-cycle shape memory performance, with shape fixation and shape recovery rates exceeding 93% after five cycles. Under near-infrared irradiation, LPU demonstrated precise non-contact heating and remote photothermal shape-control capabilities. This research not only offers a sustainable and high-value application for lignin but also advances the development of environmentally friendly intelligent shape memory polyurethane materials.

Exploring Peculiar Properties of Graded Rubber

A styrene-butadiene rubber having a gradient crosslink density in the thickness direction was simply prepared by vulcanizing under a temperature gradient to study its mechanical properties and swelling behavior. The graded rubber exhibited considerable strain recovery after stress removal despite having a low crosslinked part. Notably, the graded rubber also manifested greater hysteresis loss during cyclic test compared to a homogeneously crosslinked rubber, even though they had similar initial moduli. Furthermore, anomalous swelling behavior was observed in the graded rubber. The graded rubber exhibited shape transformation upon swelling. The mechanism was thoroughly explained using gel swelling theory under constraints. This must be a common phenomenon in graded rubbers with a crosslink gradient in the thickness direction. This comprehensive research provides a novel approach for material design with tailored properties and promising applications for this potential material.

Culture and Sketching: Comparative Analysis of UK and Chinese Designers

ABSTRACTThis research investigates the influence of culture on sketching by comparing UK and Chinese designers. We employed a novel dual‐method approach: machine learning algorithms analyzed a dataset of 2,090 digitized sketches from student designers, while protocol analysis based on shape transformation rules examined the sketching processes of professional designers from both cultures. The machine learning analysis classified sketches by extracting region‐ and shape‐based features, revealing distinctive visual attributes between the two cultures. Concurrently, protocol studies of professional designers' sketches uncovered patterns in their sketching processes. By integrating computational analyses of student sketches with protocol studies of professional designers, we identified significant cultural differences in both visual attributes and sketching processes. The paper discusses potential factors contributing to these disparities, drawing on insights from cross‐cultural comparisons of cognitive styles. This comprehensive mixed‐methods analysis provides new insights into the complex interplay between culture, cognition, and design.

Programmable Morphology-Adaptive Peptide Nanoassembly for Enhanced Catalytic Therapy.

Nanocatalytic therapy holds significant promise in cancer treatment by exploiting the high oxidative stress within tumor cells. However, efficiently delivering nanocatalytic agents to tumor tissues and maximizing their catalytic activity in situ remain critical challenges. Morphology-adaptive delivery systems, capable of adjusting their physical form in response to physiological conditions, offer unique spatiotemporal control for navigating complex biological environments like the tumor microenvironment. While designing systems that undergo multiple shape transformations often involves complex stimuli-responsive mechanisms, making programmable responses through simple designs highly desirable yet challenging. Here, FeFKC, an innovative adaptive material is introduced that achieves multi-step morphological transformations at the tissue level and amplifies catalytic activity through a straightforward design. As the microenvironmental pH decreases during drug delivery, FeFKC dynamically transitions between single chains, nanoparticles, and nanofibers. This programmable shape-shifting facilitates deep tumor penetration, enhanced cellular uptake, and lysosomal escape, significantly improving its catalytic efficiency in nanocatalytic tumor therapy. In vivo studies demonstrate that FeFKC achieves impressive tumor suppression efficacy of up to 95% without notable biosafety concerns. The findings highlight the potential of adaptive nanomaterials with programmable shape-transforming capabilities to overcome biological barriers and enhance catalytic therapy, opening new avenues for cancer treatment and other complex diseases.

Shell Ontogeny of Otoceras concavum Tozer (Ceratitida) and the Problem of the Origin of Otoceratids

As a result of a detailed study of cross sections of the most ancient (Late Permian) representatives of Otoceras Griesbach (O. concavum Tozer) from the base of the Nekuchan Formation in the upper reaches of the Vostochnaya Khandyga River in Southern Verkhoyanie, the features of ontogenetic shape changes were clarified. Trends in changes in the main parameters of the shell during its growth have been determined, the cyclical nature of the narrowing and expansion of the shell has been identified, and the sequence of changes in the shape of the whorl cross-section has been established. The formation of carinae and the emergence of a tricarinate form on the ventral side were traced. Identification of shell shape transformations in the ontogenesis of O. concavum contributes to the diagnosis of small-sized Otoceras and can serve as the basis for subsequent reconstruction of the morphogenetic development of Otoceratidae. The pentacarinate form of the outer whorl, established at the middle stage of ontogenesis, may be a character inherited from the ancestor, the genus Avushoceras Ruzhencev.

Predicting natural and unnatural red blood cell shape transformations

The nonlinear model accurately predicts the stomatocyte-discocyte-echinocyte transformation in red blood cells.

Cuboidal Deformation of Multimaterial Composites Prepared by 3-D Printing of Liquid Crystalline Elastomers.

Multimaterial 3-D printing (3DP) of isotropic (IsoE) and liquid crystalline elastomers (LCE) yields spatially programmed elements that undergo a cuboidal shape transformation upon heating. The thermomechanical deformation of 3DP elements is determined by the geometry and extent of the isotropic and anisotropic regions. The synthesis and experimental characterization of the 3DP elements are complemented by finite element analysis (FEA). Calculations emphasize that the cuboidal deformation of the myriad 3DP elements is a manifestation of local stress gradients imparted by local control of the material composition and anisotropy. Varying the rectilinear spatial distribution of the multimaterial elastomer composites produces complex, multistable states that provide insights into how stress gradients drive multimaterial elastomer actuation. The thermomechanical stimuli response of the multimaterial elements is explored as a tactile element.

Stomatocyte-discocyte-echinocyte transformations of erythrocyte modulated by membrane-cytoskeleton mechanical properties.

Stomatocyte-discocyte-echinocyte (SDE) transformations in human red blood cells (RBCs) have significant influences on blood dynamics and related disorders. The mechanical properties of the RBC membrane, such as shear modulus and bending elasticity, play crucial roles in determining RBC shapes. Recent biophysical findings reveal that building a comprehensive model capable of describing SDE shape transformations is a challenging problem. Based on dissipative particle dynamics, this study develops a two-component RBC model considering the detachment between the lipid bilayer and cytoskeleton, as well as the cytoskeletal reorganization during echinocyte formation. This model is validated by comparing RBCs' geometric shape and the apparent membrane tension with previous experimental measurements. Results indicate that a complete SDE sequence represented by six typical shapes can be obtained by modulating the model's mechanical and geometric parameters. Furthermore, a phase diagram based on reduced variables is obtained using principal-component analysis, demonstrating the phase transformations among SDE shapes. Our result suggests that the transformation from discocyte to stomatocyte is primarily influenced by dimensionless bending rigidity, whereas, during echinocyte formation, three key variables, i.e., dimensionless bending rigidity, targeting cytoskeleton shrinkage ratio, and connecting pattern, have joint impacts on the formation of spicules or bumps and the development of the cytoskeletal framework. The present two-component RBC model and the associated findings provide a perspective for a deeper understanding of the SDE transformation mechanism. This framework offers new insights into biological science and potential applications in the field of biomedical engineering.

Anisotropic dipolar vortex quantum droplets in an annular potential

Two-dimensional dipolar Bose–Einstein condensates confined within an annular potential are investigated. Stable ring-shaped anisotropic dipolar vortex quantum droplets are discovered in this configuration. These droplets remain stable under the influence of the annular potential, even with embedded vorticity up to 11. The stability regions of dipolar vortex droplets with varying embedded vorticity are confirmed through long time evolution. The characteristic parameters of the dipolar vortex droplets are systematically studied, and their existence curves are shown to contradict the well-known V–K criterion. Additionally, the shape transformation of dipolar vortex droplets induced by the strength of the mean-field interaction is examined. Finally, the behavior of dipolar vortex droplets confined within a wake-depth annular potential is also discussed.

4D Bioprinting Shape‐Morphing Tissues in Granular Support Hydrogels: Sculpting Structure and Guiding Maturation

AbstractDuring embryogenesis, organs undergo dynamic shape transformations that sculpt their final shape, composition, and function. Despite this, current organ bioprinting approaches typically employ bioinks that restrict cell‐generated morphogenetic behaviors resulting in structurally static tissues. This work introduces a novel platform that enables the bioprinting of tissues that undergo programmable and predictable 4D shape‐morphing driven by cell‐generated forces. This method utilizes embedded bioprinting to deposit collagen‐hyaluronic acid bioinks within yield‐stress granular support hydrogels that can accommodate and regulate 4D shape‐morphing through their viscoelastic properties. Importantly, precise control over 4D shape‐morphing is possible by modulating factors such as the initial print geometry, cell phenotype, bioink composition, and support hydrogel viscoelasticity. Further, shape‐morphing is found to actively sculpt cell and extracellular matrix alignment along the principal tissue axis through a stress‐avoidance mechanism. To enable predictive design of 4D shape‐morphing patterns, a finite element model is developed that accurately captures shape evolution at both the cellular and tissue levels. Finally, it is demonstrated that programmed 4D shape‐morphing enhances the structural and functional properties of iPSC‐derived heart tissues. This ability to design, predict, and program 4D shape‐morphing holds great potential for engineering organ rudiments that recapitulate morphogenetic processes to sculpt their final shape, composition, and function.

Graphene Oxide-Driven Morphological Evolution of MOF: Unleashing High Activity of Derived Co@N-Doped Carbon Electrocatalyst for Water Splitting

Developing efficient metal-supported carbon-based electrocatalysts for hydrogen evolution reaction (HER) requires tailored design of metal-organic framework (MOF) precursors. This study explores the unconventional role of graphene oxide (GO) in shaping Co-based leaf-like zeolitic imidazolate framework (ZIF-Co-L) crystals. GO was found to modulate water accessibility in the ZIF reaction medium, directing a transformation in crystal shape from leaf-shape to elongated hexagons. The morphological evolution of MOF was triggered by the presence of hydrophilic GO, which disrupted the hydrogen-bonding interactions among monodentate methylimidazole (mIm) linkers induced by inadequate water. he shape-varied MOF-derived Co-NC@10rGO-(leaf) and Co-NC@40rGO-(hexagon) electrocatalysts exhibit varying HER activity driven by crystal shape and reduced GO (rGO) content. The Co-NC@10rGO-leaf exhibited superior HER activity outperforming Co-NC@40rGO-Hex in alkaline electrolyte with an overpotential of 220 mV at 10 mA cm‒2. The excellent performance of Co-NC@rGO catalysts was attributed to unique shape features, ideal rGO content, abundant active sites, and synergistic effect of metallic Co and N-doped carbon. This shape-varied MOF-derived material approach holds great promise for developing efficient electrocatalysts for hydrogen evolution. Figure 1