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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.

In this research, we propose a reaction-diffusion system which can generate different patterns. The stabilities of equilibrium points as well as Turing bifurcation are explored. In addition, we demonstrate its effectiveness and robustness in generating patterns through numerical simulations and provide the conditions under which symmetric patterns can be formed. We discretize the proposed model using the explicit Euler method and simulate various experiments on 2D, 3D, and 3D triangular surfaces. We consider a straightforward discretization scheme for the Laplace-Beltrami operator on a triangulated surface. The results show that our model can effectively generate diifferent patterns on different types of computational domains. Furthermore, we extend our proposed model by adding a source term, resulting in a shape transformation model. The effectiveness and robustness of the model are verified through numerical experiments. [ABSTRACT FROM AUTHOR]

Abstract Breast cancer is the most common malignant tumor that threatens women’s life and health, and metastasis often occurs in the advanced stage of breast cancer, leading to pathological bone destruction and seriously reducing patient quality of life. In this study, we coupled chlorin e6 (Ce6) with mono-(6-amino-6-deoxy)-beta-cyclodextrin (β-CD) to form Ce6-CD, and combined ferrocene with the FFVLG3C peptide and PEG chains to form the triblock molecule Fc-pep-PEG. In addition, the IDO-1 inhibitor NLG919 was loaded with Ce6-CD and Fc-pep-PEG to construct the supramolecular nanoparticle NLG919@Ce6-CD/Fc-pep-PEG (NLG919@CF). After laser irradiation, Ce6 produced robust reactive oxidative species to induce tumor cell apoptosis. Simultaneously, ferrocene became charged, and Fc-pep-PEG dissociated from the spherical nanoparticles, enabling their transformation into nanofibers, which increased both the retention effect and the induction of ferroptosis. The released NLG919 reduced the number of regulatory T cells (Tregs) and restored the function of cytotoxic T lymphocytes (CTLs) by inhibiting the activity of IDO-1. Moreover, combined administration with an anti-PD-1 antibody further relieved immune suppression in the tumor microenvironment. This article presents a new strategy for the clinical treatment of breast cancer with bone metastasis and osteolysis. Graphical Abstract

Herein, a dual‐responsive shape‐transforming charge‐reversal integrated nanomedicine system (DHP@BPP) is developed for the co‐delivery of the photosensitizer pyro pheophorbide‐α (Ppa), anti‐programmed cell death ligand 1 (PD‐L1) peptide (dPPA), and tumor‐associated macrophages (TAMs)‐regulating drug berberrubine (BBR). Hydrophobic Ppa and hydrophilic BBR are linked by matrix metalloproteinase‐2 (MMP‐2) responsive peptide (PMGMRKLVFF) to form BPP. BPP can self‐assemble into spherical nanoparticles with positive charge, which undergo shape transformation to nanofibers upon cleavage by MMP‐2 at tumor sites. The dPPA is conjugated with hexa‐histidine and polyethylene glycol to form DHP, which is then electrostatically adsorbed onto the surface of BPP to form DHP@BPP with negative surface charge. The DHP not only enhances the tumor‐targeting but also induces DHP disassociation and charge reversal of DHP@BPP due to protonation of histidine at the tumor site, thereby increasing tumor penetration while maintaining long blood circulation. Most importantly, through the combination of chemo‐photodynamic‐immunotherapy, it can repolarize TAMs from M2‐type to M1‐type while reducing PD‐L1 expression to reshape the immunosuppressive tumor microenvironment, thereby synergistically enhancing the effect of immunogenic cell death. In conclusion, this study offered a simple but effective idea for the treatment of immunosuppressive cancers through the combination of shape transformation and charge reversal, integrating chemo‐photodynamic‐immunotherapy. [ABSTRACT FROM AUTHOR]

The field of 3D and 4D printing is advancing rapidly, offering new ways to control the transformation of programmable 3D structures in response to external stimuli. This study examines the impact of 3D printing parameters, namely the UV ink thickness (applied using a UV inkjet printer on pre-3D-printed programmable structures) and thermal activation, on the dimensional and surface changes to high-stress (HS) and low-stress (LS) programmable samples and on print quality. The results indicate that HS samples shrink in the longitudinal direction, while expanding in terms of their height and width, whereas LS samples exhibit minimal dimensional changes due to lower programmed stress. The dynamic mechanical analysis shows that UV ink, particularly cyan and CMYK overprints, reduces the shrinkage in HS samples by acting as a resistive layer. Thicker ink films further reduce the dimensional changes in HS samples. Thermal activation increases the surface roughness of HS structures, leading to the wrinkling of UV ink films, while LS structures are less affected. The surface gloss decreases significantly in HS structures after UV ink application; however, thermal activation has little impact on LS structures. UV ink adhesion remains strong across both HS and LS samples, suggesting that UV inks are ideal for printing on programmable 3D structures, where the colour print quality and precise control of the shape transformation are crucial. [ABSTRACT FROM AUTHOR]

Breast cancer is the most common malignant tumor that threatens women's life and health, and metastasis often occurs in the advanced stage of breast cancer, leading to pathological bone destruction and seriously reducing patient quality of life. In this study, we coupled chlorin e6 (Ce6) with mono-(6-amino-6-deoxy)-beta-cyclodextrin (β-CD) to form Ce6-CD, and combined ferrocene with the FFVLG3C peptide and PEG chains to form the triblock molecule Fc-pep-PEG. In addition, the IDO-1 inhibitor NLG919 was loaded with Ce6-CD and Fc-pep-PEG to construct the supramolecular nanoparticle NLG919@Ce6-CD/Fc-pep-PEG (NLG919@CF). After laser irradiation, Ce6 produced robust reactive oxidative species to induce tumor cell apoptosis. Simultaneously, ferrocene became charged, and Fc-pep-PEG dissociated from the spherical nanoparticles, enabling their transformation into nanofibers, which increased both the retention effect and the induction of ferroptosis. The released NLG919 reduced the number of regulatory T cells (Tregs) and restored the function of cytotoxic T lymphocytes (CTLs) by inhibiting the activity of IDO-1. Moreover, combined administration with an anti-PD-1 antibody further relieved immune suppression in the tumor microenvironment. This article presents a new strategy for the clinical treatment of breast cancer with bone metastasis and osteolysis. [ABSTRACT FROM AUTHOR]

Aim: This study was twofold: (i) it aimed to investigate the morphometric changes of three temperature‐sensitive nickel–titanium (NiTi) instruments at different temperatures, and (ii) to conduct an in vivo real‐time analysis of intracanal temperature changes. Methods: Changes in the shape and length of XP‐Endo Shaper, XP‐Endo Finisher, and XP‐Endo Finisher‐R were evaluated in real time whilst heated in a temperature‐controlled water bath from 22 to 45°C. Instruments were fixed to a laminated water‐resistant 1 mm graph paper attached to a stone block. Instruments were imaged whilst subjected to increasing temperature using a digital camera attached to an operating microscope. From recorded videos, still frames were extracted at 10‐s intervals and changes in the length and shape of each instrument were measured and changes were plotted against time. Moreover, the intracanal temperature of distal roots of lower molars was measured in vivo for patients attending the clinic for non‐surgical root canal treatments. The temperature was measured using a K‐type thermocouple probe inserted into the mid‐root level after irrigating the canal with a solution set at room temperature (22°C) or heated to 45°C. The intraoral and intracanal temperatures were recorded using a video camera for 180 s at 5‐s intervals to plot the change in the intraoral and intracanal temperature, after both irrigation solution temperatures, with time. Results: The shape transformation of XP‐Endo Shaper began at 31.5 ± 2.0°C and reached its optimal transformation at 35.1 ± 1.0°C. For the Finisher and Finisher‐R, shape transformations began at 29.2 ± 1.9 and 26.9 ± 2.2°C reaching the optimal transformation at 33.9 ± 1.4 and 32.7 ± 1.7°C, respectively. The average decreases in lengths of XP‐Endo Shaper, Finisher, and Finisher‐R after full transformation were 0.43 ± 0.23, 1.07 ± 0.22, and 1.15 ± 0.22 mm, respectively. The intracanal temperature reached 32.9 ± 0.8 and 33.2 ± 1.0°C after 3 min of application of irrigation solutions set at 22 or 45°C, respectively. Conclusion: The tested instruments exhibited diverse changes in their shapes and lengths at varying temperatures. Despite the temperature of the irrigation solution, the intracanal temperature consistently remained lower than the intracanal temperature once equilibrium was reached. This highlights the importance of considering the temperature of irrigation solution during in vitro testing of endodontic instruments. [ABSTRACT FROM AUTHOR]

The 3D bioprinting of complex structures has attracted particular attention in recent years and has been explored in several fields, including dentistry, pharmaceutical technology, medical devices, and tissue/organ engineering. However, it still possesses major challenges, such as decreased cell viability due to the prolongation of the printing time, along with difficulties in preserving the print shape. The 4D bioprinting approach, which is based on controlled shape transformation upon stimulation after 3D bioprinting, is a promising innovative method to overcome these difficulties. Herein, the generation of skeletal muscle tissue‐like complex structures is demonstrated by 3D bioprinting of GelMA‐based C2C12 mouse myoblast‐laden bio‐ink on a polymeric magnetic actuator that enables on‐demand shape transformation (i.e., rolling motion) under a magnetic field. Bioprinted scaffolds are used in both unrolled (open as control) and rolled forms. The results indicate that C2C12s remain viable upon controlled shape transformation, and functional myotube formation is initiated by the 7th day within bioprinted platforms. Moreover, when the rolled and open groups are compared regarding MyoD1 staining intensity, the rolled one enhanced MyoD1 expression. These results provide a promising methodology for generating complex structures with a simple magnetic actuation procedure for the bioprinting of tissue‐engineered constructs with enhanced cell viability and functionality. [ABSTRACT FROM AUTHOR]

The manipulation of nano-objects through heating is an effective strategy for inducing structural modifications and therefore changing the optoelectronic properties of semiconducting materials. Despite its potential, the underlying mechanism of the structural transformations remains elusive, largely due to the challenges associated with their in situ observations. To address these issues, we synthesize temperature-sensitive CsPbBr3 perovskite nanoplatelets and investigate their structural evolution at the nanoscale using in situ heating transmission electron microscopy. We observe the morphological changes that start from the self-assembly of the nanoplatelets into ribbons on a substrate. We identify several paths of merging nanoplates within ribbons that ultimately lead to the formation of nanosheets dispersed randomly on the substrate. These observations are supported by molecular dynamics simulations. We correlate the various paths for merging to the random orientation of the initial ribbons along with the ligand mobility (especially from the edges of the nanoplatelets). This leads to the preferential growth of individual nanosheets and the merging of neighboring ones. These processes enable the creation of structures with tunable emission, ranging from blue to green, all from a single material. Our real-time observations of the transformation of perovskite 2D nanocrystals reveal a route to achieve large-area nanosheets by controlling the initial orientation of the self-assembled objects with potential for large-scale applications.

4D printing of composites (4DPC) is a technique that allows the manufacturing of composite structures to shape without the use of a complex-shaped mold. Instead, only a flat mold is utilized. This innovative technique has been employed to make composite leaf springs with performance comparable to metallic springs, omega stiffeners, and corrugated core for flexible wings. Recently, this technique was applied to fabricate composite conical shells. While experimental work has successfully demonstrated the transformation from flat to conical shape, the development of a numerical method to replicate this transformation is highly desirable. The availability of such method not only provides theoretical support for the experimental result, it also provides means to develop other shapes. The lay-up sequence for transforming flat to conical shapes involves curvilinear fibers. Most if not all finite elements currently available deal only with straight fibers (even though the boundaries of the element may be curved). The objective of this research is to examine the efficiency of the analysis for the deformation of composite from flat to curve made by 4DPC by special finite elements containing curved fibers. The developed finite elements were used to determine the shapes of conical shells made using multiple distinct lay-up sequences. The direction of bending in curvilinear fiber structures is significantly influenced by the orientation of the fibers. This highlights the critical role of fiber orientation and layer composition in achieving desired shapes in 4D printed composites.

4D printing of composites (4DPC) is a technique that can make composite structures with curved geometry without the need to use a curved mold (only a flat mold is used). This technique has been used to make composite springs and cones, where not only the shape is obtained but the mechanical properties are equivalent to those made using conventional technique (where a curved mold is used). The principle of operation of 4DPC utilized anisotropy in unsymmetric laminates as the mechanism for the shape transformation. However it is not always straightforward that a certain unsymmetric lay-up of composite layers will provide a certain shape. Hyer [1,2] observed that laminate theory is accurate to predict the shape of the [0/90] laminate only in some cases, but not in all cases. He attributed this to the assumption of linear relation between the strains and displacements. He then used the non-linear relation between strains and displacements and assumed some functional forms for them. This approach was able to predict the shape of square thin laminates such as those made of [0/90] and [02/902] lay sequences, but not for rectangular laminates or laminates of other shapes. Finite element method was also used for this prediction. This method worked only with some twikking of the modeling procedure. As such work of previous researchers in the past more than 40 years only show success in ad-hoc situations. The reason for this is due to the lack of an explanation for why there are so many different shapes in different situations. The work in this paper provides an explanation as to why there are different shapes for different situations. This understanding provides a direction for the development of a new finite element procedure that can determine the shape of the laminates in different situations. The new understanding is used to explain the behavior of many cases. This new finite element procedure is then used to generate guidelines on the effect of different parameters such as the effect of geometric dimensions, and material properties on the final shape. These guidelines are useful for the selection of lay-up sequences to make structures in the technique of 4D printing of composites.

Voxel modeling is a technique in which an object is represented by an array of cubes. One advantage in design-for-manufacturing is that selected voxels may be assigned desired responsive properties through additive manufacturing. It allows for achieving reversible shape transformation in soft responsive self-repairing solids within a strategic sequence. The first step in the sequence involves selecting an equivalent geometric shape. The second step involves mapping shapes to preserve properties during continuous deformation. The third step involves transforming the shape from one form to another. The fourth step involves defining changes in dimensions. The final step involves correlating the flow of stress with the stretch of the solid. This research also considers self-repair or self-healing as part of the transformation process because the splitting or joining of solids involves continuous deformation. The newly transformed shape can also be considered as the intermediate shape, or first shape for next transformation. This leads to a chain of shapes that are topologically equivalent, and interchangeable. The iterative steps involved in shape transformation finds applications in topology optimization, generative design, metastructures, among others. One application of shape transformation in these domains is that it serves as an alternative to material reduction techniques.

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It remains challenging to broaden the application fields of ceramics, largely because the hardness and brittleness of ceramics mean that they cannot undergo shape reconfiguration. In this study, we developed an ultraviolet light-curable preceramic polymer slurry, and this slurry was used for digital light processing printing of flexible green parts in designed shapes. These parts were subsequently transformed into complex structures by an assisted secondary molding strategy that enabled the morphology of their green and pyrolyzed forms to be well controlled. The collapse of bulk pyrolyzed parts was avoided by impregnating their precursors with silicon nitride (Si3N4) particles. The effects of different proportions of Si3N4 on the weight loss, shrinkage, density, porosity, and mechanical properties of the pyrolyzed composites were investigated, and the bending strength and Vickers hardness of the composites with 10 wt.% Si3N4 were found to be 130.61 ± 16.01 MPa and 6.43 ± 0.12 GPa, respectively.

In this paper, we propose a simple and fast shape transformation method. This method is based on the Allen-Cahn (AC) partial differential equation and uses the edge stop function to constrain evolution. We use the operator splitting method to control the equation for splitting, and use the explicit Euler's method to solve the discrete equation. Based on the source shape and the target shape, our phase-field model can perform rapid shape transformation when the appropriate parameters are selected. In order to verify the feasibility of our proposed phase-field model, numerical experiments on shape transformation are carried out in two-dimensional and three-dimensional space. The results show that the established mathematical model can not only perform shape transformation between simple shapes, but also have a good effect on shape transformation between complex shapes. We also propose a numerical solution using the Crank-Nicolson numerical scheme to handle the model we introduced. This numerical scheme utilizes the multigrid method and Gauss-Seidel iteration for solving. The results of the numerical experiments demonstrate the effectiveness of this numerical method in handling shape transformations in three-dimensional space. [ABSTRACT FROM AUTHOR]

Fabricating nanoscale assemblies that can respond to gas signaling molecules has emerged as a field of growing interest owing to their unique biomedical applications in gas‐guided delivery and gas therapeutics. Yet, among a variety of endogenous gaseous biosignals, exploiting sulfur dioxide (SO2) as a cue for controllable self‐assembly remains elusive, despite its crucial two‐sided roles both in physiology and pathology. Here we show a SO2‐responsive polymersome system assembled from a novel class of cyanine‐containing block copolymers. By intake of SO2 gas, the tautomerism of cyanine drives such vesicles to continuously deform, and change into long nanotubes through axial stretching and anisotropic extrusion of the membranes. Unexpectedly, during this order‐to‐order phase transition, their membranes manifest well SO2‐dose‐dependent permselectivity, which allows the cargos of different sizes loaded therein to be selectively transferred across the bilayers. This study would inspire us to better understand and mimic the function of gas signaling molecules in shifting biomembrane shape and managing transmembrane traffic. [ABSTRACT FROM AUTHOR]

The 3D shape‐changing hydrogels are highly pursued for numerous applications. However, up to now, the construction of complex 3D shape‐changing hydrogels remains a challenge. The reported design strategies are mainly applied to fabricate 2D ones by introducing anisotropic microstructures into hydrogel sheets/membranes. Herein, we present a convenient photolithography strategy for constructing complex 3D shape‐changing hydrogels by simultaneously modulating anisotropic microstructures and internal stress fields of gel sheets. When the precursor solution containing ultraviolet (UV) absorber is irradiated by single‐side UV light, the attenuated polymerization rate can cause the generation of asymmetric internal stress field in the resulting hydrogel sheet. In the meantime, the directional diffusion of unpolymerized monomers allows for the formation of vertical gradient structure within hydrogel. Therefore, by applying different photomasks to modulate the local gradient structures and internal stress fields of the gel sheets, they can spontaneously transform into various complex 3D shape‐changing hydrogels in the air. Response to the external stimuli, these 3D shape‐changing hydrogels (e.g., fighter plane, birdie, and multi‐storey origami lattices) can deform in a novel 3D1‐to‐3D2‐to‐3D3 mode. This new design strategy contributes to the development of complex biomedical implants and soft robotics. [ABSTRACT FROM AUTHOR]

Herein, we designed a dual-response shape transformation and charge reversal strategy with chemo-photodynamic therapy to improve the blood circulation time, tumor penetration and retention, which finally enhanced the anti-tumor effect. In the system, hydrophobic photosensitizer chlorin e6 (Ce6), hydrophilic chemotherapeutic drug berberrubine (BBR) and matrix metalloproteinase-2 (MMP-2) response peptide (PLGVRKLVFF) were coupled by linkers to form a linear triblock molecule BBR-PLGVRKLVFF-Ce6 (BPC), which can self-assemble into nanoparticles. Then, positively charged BPC and polyethylene glycol-histidine (PEG-His) were mixed to form PEG-His@BPC with negative surface charge and long blood circulation time. Due to the acidic tumor microenvironment, the PEG shell was detached from PEG-His@BPC attributing to protonation of the histidine, which achieved charge reversal, size reduction and enhanced tumor penetration. At the same time, enzyme cutting site was exposed, and the spherical nanoparticles could transform into nanofibers following the enzymolysis by MMP-2, while BBR was released to kill tumors by inducing apoptosis. Compared with original nanoparticles, the nanofibers with photosensitizer Ce6 retained within tumor site for a longer time. Collectively, we provided a good example to fully use the intrinsic properties of different drugs and linkers to construct tumor microenvironment-responsive charge reversal and shape transformable nanoparticles with synergistic antitumor effect.

The design of novel polymer gels possessing elaborate and efficient properties remains a grand challenge. Here, a zwitterionic network was constructed in a polyanionic cellulose matrix to prepare a series of pol3-[dimethyl- [2-(2-methylprop-2-enoyloxy)ethyl] azaniumyl]propane-1-sulfonate/polyanionic cellulose gels (AAC gels). AAC gels with electrostatic interaction and hydrogen bonding interaction present high mechanical property (∼1350 %/∼0.50 MPa), self-healing performance, self-adhesion, low-temperature resistance, recyclability, ultraviolet (UV) shielding, and antibacterial ability. The information of repeated writing, erasing, and encoding is realized by combining the UV visualization and self-healing performance. Impressively, it has proven the function of successive encryption-decryption process and dual encryption, as well as continuous and reversible dynamic transparency shifting in analogy to dynamic memorizing-forgetting behavior. More interestingly, a spontaneous shape-morphing of AAC'-polyacrylamide (AAC'-PAM) gel with bilayer structure can be obtained by depositing covalently cross-linked PAM. The mismatch strain/stress induces more rapid shape transformation (e.g., bending and grasping objects; ∼22 s) than the currently reported responsive gels due to the disassociation and reformation of the electrostatic interaction. The shape transformation and the information visualization under UV light are further combined to achieve the dual encryption. This study provides a novel strategy for designing and fabricating smart gels with elaborate and efficient functionality. [ABSTRACT FROM AUTHOR]

In this research, for the first time, highly controllable self-coiling and tensile shape memory behaviors of the 3D printed (Poly-Ethylene Terephthalate Glycol) PETG thermoplastic structures, as a novel shape memory polymer (SMP), are introduced. The results showed that the maximum printing-induced pre-strain of the PETG is stored in the first printed layer. Manipulating the infill printing direction of the 3D printed PETG strip provides different controllable shape transformation modes, including bending and spiraling. The wall effect experiments indicated that the shape transformation related to the infill pattern weakens by increasing the wall size. Employing a cross printing pattern resulted in the strip's more intense self-spiraling behavior, making the final shape transformation mode less influenced by the wall size. The shape transformation of the planar rectangular surfaces printed with single and cross printing patterns caused a self-tubing shape transformation in half and full tubes, respectively. Mechanical and biomedical potential applications of the PETG 3D printed parts' shape transformation are defined as a self-deployable spiral stent, self-conforming supporting splint, mechanical fastening, and self-locking planarly printed gripper to grab spherical, slippery, and soft objects that are hard to grab. The tensile shape memory test was done on a dog-bone tensile sample printed with a cross pattern to evaluate the effect of the first layer's printing direction, programming temperature, and strain rate on the tensile shape memory performance. Hot programmed samples (Tg+10 °C) exhibited a higher shape fixity and weaker strain recovery than warm programmed samples (Tg). Warm programmed samples showed full strain recovery with a considerable downward self-bending in their recovered shape, but hot programmed samples did not show any curvature. This behavior intensifies by increasing the stretching percentage. Also, changing the first printed layer's direction from the longitudinal to the transverse condition prevented the from self-bending during the recovery process. A twentyfold increase in the deformation speed for the warm programming condition resulted in a doubled gentler undesired self-bending and a 14.3% higher shape recovery.

Cereal‐based functional foods with shape‐changing (four‐dimensional [4D]) properties is a novel approach in the current scenario. The main objective of the research is to develop a bioactive compound incorporated in flat two‐dimensional xerogel and its hydromorphic three‐dimensional shape transformation. The spray‐dried curcumin at three different concentrations was incorporated with hydrogel (wheat–barley flour 8%), and flat xerogel was formed by sessile drop drying at 30°C and 78% relative humidity. The top smooth and rough bottom surface of xerogel provided anisotropic swelling properties during the shape transformation. The antimicrobial and antioxidant properties of xerogel were examined, and the retention of curcumin during the shape transformation was also examined during the research. The porous structure of barley–wheat xerogel has enhanced the incorporation of water‐insoluble bioactive components like curcumin. The diffusion properties of curcumin xerogel provided an antimicrobial effect against gram‐negative pathogenic bacteria. The optimum temperature (70°C) during the shape‐shifting provides the retention of bioavailability and functional properties of curcumin. The work describes the opportunities for developing xerogel incorporated with more bioactive and functional components and study its stability and hydromorphic 4D shape‐changing behavior. Practical Application: Xerogel is a good carrier for different bioactive components. The development of curcumin‐infused biodegrade, non‐toxic, and cereal‐based xerogel provide an excellent opportunity for the delivery of curcumin in a cost‐effective way. The shape‐changing easily consumable forms of xerogel will attract more consumers, and it retains the bioavailability of infused compounds during processing. [ABSTRACT FROM AUTHOR]

Summary: Shape transforming foods are an emerging area of interest that could be customised according to consumer needs with the desirable structure and reduced package space. The current work aims to investigate the shape transformation behaviour of a 2D xerogel developed from rice hydrogel at the concentration of 4% and 90 °C. This flat xerogel is coated with ethyl cellulose as constraint material in the form of linear equally spaced strips. Immersing the xerogels in hot water over a temperature of 70 °C, resulted in a 3D transformation of the discs in 12 s (Video S1). The transformation is achieved owing to xerogel's increased swelling power (0.27–0.78) due to the anisotropic nature. This is confirmed by the SEM images of top (smooth) and bottom (rough) xerogel. In order to characterise the process of shape transformation bending analysis was done wherein a significant difference in bending angle (35.86–63.10°), height (24.73–50.26 mm), curvature (0.57–2.38 μ mm−1) and end‐to‐end distance (118.23–15.11 mm) from 2 to 12 s. The formed 3D shape was similar to the commercial tubular (penne) pasta. This study opens up the utilisation of less concentrated rice xerogel in shape transformation for designing engineered food. [ABSTRACT FROM AUTHOR]

The clearance of nanomedicine in inflamed joints has been accelerated due to the increased lymph angiogenesis and lymph flow in arthritic sites. To maximize the therapeutic efficacy for rheumatoid arthritis (RA), it is necessary to facilitate targeted delivery and extended drug retention in inflamed synovium simultaneously. In general, nanosized particles are more likely to achieve prolonged circulation and targeted delivery. While drug carriers with larger dimension might be more beneficial for extending drug retention. To balance the conflicting requirements, an inflammation-responsive shape transformable nanoparticle, comprised of amyloid β-derived KLVFF peptide and polysialic acid (PSA), coupled with therapeutic agent dexamethasone (Dex) via an acid-sensitive linker, was fabricated and termed as Dex-KLVFF-PSA (DKPNPs). Under physiological condition, DKPNPs can keep stable nanosized morphology, and PSA shell could endow DKPNPs with long circulation and active targeting to arthritic sites. While in inflamed joints, acidic pH-triggered Dex dissociation or macrophages-induced specific binding with PSA would induce the re-assembly of DKPNPs from nanoparticles to nanofibers. Our results reveal that intravenously injected DKPNPs display prolonged in vivo circulation and preferential distribution in inflamed joints, where DKPNPs undergo shape transition to fibrous structures, leading to declined lymphatic clearance and prolonged efficacy. Overall, our dual-stimulus responsive transformable nanoparticle offers an intelligent solution to achieve enhanced therapeutic efficacy in RA. In inflamed joints, acidic pH or macrophages would induce the re-assembly of DKPNPs from nanoparticles to nanofibers, leading to declined lymphatic clearance and prolonged therapeutic efficacy. [Display omitted] • PSA shell endowed DKPNPs with long circulation and active targeting to arthritic sites. • When reaching inflamed sites, local acidic pH or macrophages triggered the transition of DKPNPs from nanoparticles to fibers. • The fiber formation in inflamed sites declined lymphatic clearance and prolonged therapeutic efficacy. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing enables the fabrication of complex, highly customizable structures, which are difficult to fabricate using conventional fabrication methods. Recently, the concept of four-dimensional (4D) printing has emerged, which adds active and responsive functions to 3D-printed structures. Deployable or adaptive structures with desired structural and functional changes can be fabricated using 4D printing; thus, 4D printing can be applied to actuators, soft robots, sensors, medical devices, and active and reconfigurable photonic devices. The shape of 3D-printed structures can be transformed in response to external stimuli, such as heat, light, electric and magnetic fields, and humidity. Light has unique advantages as a stimulus for active devices because it can remotely and selectively induce structural changes. There have been studies on the light activation of nanomaterial composites, but they were limited to rather simple planar structures. Recently, the light activation of 3D-printed complex structures has attracted increasing attention. However, there has been no comprehensive review of this emerging topic yet. In this paper, we present a comprehensive review of the light activation of 3D-printed structures. First, we introduce representative smart materials and general shape-changing mechanisms in 4D printing. Then, we focus on the design and recent demonstration of remote light activation, particularly detailing photothermal activations based on nanomaterial composites. We explain the light activation of 3D-printed structures from the millimeter to sub-micrometer scale.

Superabsorbent polymers are materials that exhibit a high swelling behavior in liquids and can hold the absorbed liquid even against externally applied pressure. They are commercially used, for example, in baby diapers, fake snow, or swellable children's toys. Most commercially available superabsorbent polymers are based on polymerized and crosslinked sodium acrylate. Here, a material formulation to create 3D objects using stereolithographic printing of sodium acrylate is demonstrated. The material shows typical superabsorbent properties that cannot be reached with conventional 3D printing materials. The printed structures swell strongly (up to 20 times in weight) in aqueous environments and still show 65% of the swelling under an external load of 100 kPa. This swelling can be used for 3D printed parts that can automatically change their size or shape when exposed to water. To show the versatility of this approach, selected structures are 3D printed, including a ship and a medical stent. Also the applicability of actuation by printing a structure is demonstrated, which deforms to a self‐closing container upon exposure to water. [ABSTRACT FROM AUTHOR]

Shape‐transforming block copolymer (BCP) microparticles have attracted extensive attention due to their promising applications in nanotechnology, biomedicines, interfacial science, and other fields. As their performance is highly associated to their shape and structure, it is very important to realize the precise control of particle shape. In this report, a method is proposed to regulate the shape and structure of polystyrene‐b‐polydimethoxysiloxane (PS‐b‐PDMS) microparticles by using positively charged core‐crosslinked nanoparticles (CNPs) as a cosurfactant, combining with cationic surfactant cetyltrimethylammonium bromide (CTAB). The electrostatic repulsive interactions between CNPs and CTAB dominate the shape of PS‐b‐PDMS particles. Upon introducing NaCl, the electrostatic repulsion is reduced, resulting in the reshape of PS‐b‐PDMS particles from striped Janus ellipsoids to onion‐like microspheres at a critical concentration of NaCl (cNaCl). Interestingly, it is found that the critical cNaCl first increases then reaches a plateau, with the increase in the crosslinking degree of the CNPs. The work provides a simple strategy to tailor the morphology of BCPs by manipulating the electrostatic interaction. [ABSTRACT FROM AUTHOR]

In this paper, a novel numerical algorithm for efficient modeling of three-dimensional shape transformation governed by the modified Allen-Cahn (A-C) equation is developed, which has important significance for computer science and graphics technology. The new idea of the proposed method is as follows. Firstly, the operator splitting method is used to decompose the three-dimensional problem into a series of one-dimensional subproblems that can be solved in parallel in the same direction. Secondly, a temporal p-adaptive strategy, which is based on the extrapolation technique, is proposed to improve the convergence order in time and preserve the computational efficiency simultaneously. Finally, a parallel least distance modification technique is developed to force the discrete maximum bound principle. The proposed method achieves high precision and high efficiency at the same time. Numerical examples include the effectiveness of the p-adaptive method and the bound preserving least distance modification, and a series of complex three-dimensional shape transformation modelings. • The operator splitting method is used to solve 3D shape transformation PDE. • A temporal p-adaptive strategy is developed to improve computational efficiency. • A least-distance modification is developed to force the discrete maximum bound. [ABSTRACT FROM AUTHOR]

Herein, we designed a dual-response shape transformation and charge reversal strategy with chemo-photodynamic therapy to improve the blood circulation time, tumor penetration and retention, which finally enhanced the anti-tumor effect. In the system, hydrophobic photosensitizer chlorin e6 (Ce6), hydrophilic chemotherapeutic drug berberrubine (BBR) and matrix metalloproteinase-2 (MMP-2) response peptide (PLGVRKLVFF) were coupled by linkers to form a linear triblock molecule BBR-PLGVRKLVFF-Ce6 (BPC), which can self-assemble into nanoparticles. Then, positively charged BPC and polyethylene glycol-histidine (PEG-His) were mixed to form PEG-His@BPC with negative surface charge and long blood circulation time. Due to the acidic tumor microenvironment, the PEG shell was detached from PEG-His@BPC attributing to protonation of the histidine, which achieved charge reversal, size reduction and enhanced tumor penetration. At the same time, enzyme cutting site was exposed, and the spherical nanoparticles could transform into nanofibers following the enzymolysis by MMP-2, while BBR was released to kill tumors by inducing apoptosis. Compared with original nanoparticles, the nanofibers with photosensitizer Ce6 retained within tumor site for a longer time. Collectively, we provided a good example to fully use the intrinsic properties of different drugs and linkers to construct tumor microenvironment-responsive charge reversal and shape transformable nanoparticles with synergistic antitumor effect. The nanoparticle with transformable shape and reversible charge, PEG-His@BPC, conquered the drug delivery challenge of tumor targeting, cellular uptake, tumor penetration and tumor retention, which successfully amplified chemo-photodynamic therapy of breast cancer and obviously inhibited the growth of the tumor. [Display omitted] [ABSTRACT FROM AUTHOR]

The stimuli‐responsive transition of nanostructures from amorphous to crystalline state is of high interest in polymer science, but is still challenging. Herein, the transformation of amorphous nanobowls to crystalline ellipsoids triggered by UV induced trans‐cis isomerization is demonstrated, using an azobenzene‐containing amphiphilic homopolymer (PAzoAA) as a building block. The amide bond and azobenzene pendants are introduced to the side chain of PAzoAA to afford hydrogen bonding and π–π interactions, which promote the formation of nanobowls rather than spherical nanostructures. Upon exposure to UV irradiation, trans‐cis isomerization of azobenzene pendants occurs, leading to the increase of hydrophilicity and destruction of π–π interaction, further resulting in the disassembly of the nanobowls. Then the PAzoAA re‐assembles to form crystalline ellipsoids instead of amorphous nanostructures when recovered at 70 °C without UV light. Further, it is confirmed that the high incubation temperature after UV irradiation is critical for the cis‐trans transformation and the high mobility of the polymer chains to facilitate the regular rearrangement of azobenzene pendants. Overall, a facile method to achieve the transformation of amorphous nanobowls to crystalline ellipsoids is proposed, which may bring new insight into preparation of crystalline nanoparticles using amorphous precursors. [ABSTRACT FROM AUTHOR]

We present a computational method for the 3D volume reconstruction from cross-sectional data. The proposed method is based on the Allen–Cahn (AC) equation with a source term. The source term is related to shape transformation from a source object to a target object. Using the operator splitting method, the governing equation is solved by splitting it into three steps. The numerical solution is obtained explicitly using the Euler's methods and the separation of variables. To reconstruct the 3D object from two slice data, we set one slice as the target data and the other data as the initial data. We solve the governing equation and stack intermediate solutions based on the relative fraction of the symmetric difference of two regions occupied by the target and source data. To demonstrate that the proposed method can reconstruct a 3D model through extracted intermediate slice data during shape transformation, we perform several computational tests. Furthermore, the proposed method is applied to a 3D volume reconstruction from multi-slice data of human vertebra. [ABSTRACT FROM AUTHOR]

Carefully designed geometries and materials can program desired shapes. In this review, we introduce shape-transformable materials and their recent applications in electronic devices and robots. Strain-guiding shape transformation can be achieved by geometry design or materials design, which can program the magnitude and direction of strain to develop desired shapes. For the geometry design, we discuss origami and kirigami, which transform 2D sheet materials into desired 3D shapes via local deformations caused by fold creases and cut openings. The desired shape can be programmed by controlling the length and alignment of folds or cuts. For the material design, heterogeneities in materials can develop strain driven shape transformation. Heterogeneities in materials include those in anisotropic materials, graded materials, or mixtures of different materials. Shape-transformable materials can be prepared by introducing heterogeneities into stimuli-responsive materials, including inflatable materials, shape memory polymers, liquid crystal elastomers, and hydrogels. The development of shape-transformable materials has led to innovations in energy storage devices, displays, sensors, epidermal electronics, actuators, and robots. [ABSTRACT FROM AUTHOR]

Plasmon-mediated shape transformation from quasi-spherical silver nanoparticles (AgNPs) to silver nanoprisms (AgNPrs) and decahedral silver nanoparticles (D-AgNPs) under irradiation of blue LEDs (λ = 456 ± 12 nm, 80 mW/cm2) was studied at temperatures ranging between 60, 40, 30, 20, 10, and 0 °C. It was found that reaction temperature affected transformation rates and influenced the morphology distribution of final products. The major products synthesized at temperatures between 60 °C and 0 °C were AgNPrs and D-AgNPs, respectively. The D-AgNPs synthesized at such low temperatures are unstable and become blunt when light irradiation is removed after the photochemical synthesis. These blunt nanoparticles with pentagonal multiple-twinned structures can be further used as the seeds to reconstruct complete D-AgNPs after irradiating blue LEDs at various bath temperatures. Our results showed that these rebuilt D-AgNPs are much more stable when at higher bath temperatures. Furthermore, the rebuilt D-AgNPs (edge lengths ~41 nm) can grow into larger D-AgNPs (edge lengths ~53 nm) after the irradiation of green LEDs. Surface-enhanced Raman spectra of CV in AgNP colloids showed that D-AgNP colloids have better SERS enhancements factors than AgNPrs. [ABSTRACT FROM AUTHOR]

Predicting the shape transformation of micro- and nano-scale structures in bulk silicon and silicon-on-insulator (SOI) material in a hydrogen annealing process can be challenging due to the volume segmentation that is likely to occur for longer process times and the long-ranging surface diffusion of silicon atoms. We present a method that allows to accurately predict the shape transformation in such a process, including the modeling of any volume segmentation. This method allows determining the geometry and size of a silicon feature before hydrogen annealing in order to obtain a desired structure after the process. The presented approach allows validating the outcome of a hydrogen annealing process of a given, pre-patterned silicon structure. Experimental results of hydrogen-annealed micro-and nano-scale structures are presented alongside their simulated counterparts to verify the applicability of the proposed method further. [2021-0016] [ABSTRACT FROM AUTHOR]

Minimizing damage during the insertion of stents or other medical devices is critical for rapid and successful recovery. Since the delivery passages are often narrower than the size of the delivered object, a high deformability of the implanted devices is paramount to achieve a smooth insertion into the target tissue. In this study, a novel design of 3D‐printable and highly deformable structures inspired by Nanjing Tamasudare is proposed. These structures rapidly change dimensionality from flat to linear, elongated shapes. A series of single units that each comprises two interconnected rods and attaching loops are directly 3D‐printed without classical assembly or fabrication. Multiple units are connected together but remain individually movable and deformable. The smooth changes of the unit assembly, including shifting, bending, and inclination, allow to transform the structure from an initially condensed state to various types of target shapes. To verify the transformation capabilities, smooth insertion of the 3D‐printed structure in a mock‐up vessel through a small opening in an elongated state is demonstrated. After insertion, the units are reassembled to a stent‐like structure within the vessel. The authors believe that this 3D‐printable and highly transformable design is widely applicable for insertion operations of implantable devices or electronics. [ABSTRACT FROM AUTHOR]

Polymersomes have gained a lot of attention in recent years. Their compartmentalized, hollow nature, stability and ability to transport both hydrophilic and hydrophobic cargo has made them attractive for increasingly complex applications in various fields of biomedicine, catalysis and diagnostics. Progress in these fields would therefore benefit from improvements in polymersome functionality. Recently, morphological control of polymersomes, namely the fabrication of various non‐spherical morphologies, has emerged as a means to enhance the usefulness of the polymersomes. In the present review, we highlight the most topical trends in this field and how these developments and the newly acquired knowledge about their nature can be leveraged towards applications. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]