Interface stress transfer model and modulus parameter equivalence method for composite materials embedded with tensile pre-strain shape memory alloy fibers.

The constitutive model and modulus parameter equivalence of shape memory alloy composites (SMAC) serve as the foundation for the structural dynamic modeling of composite materials, which has a direct impact on the dynamic characteristics and modeling accuracy of SMAC. This article proposes a homogenization method for SMA composites considering interfacial phases, models the interface stress transfer of three-phase cylinders physically, and derives the axial and shear stresses of SMA fiber phase, interfacial phase, and matrix phase mathematically. The homogenization method and stress expression were then used to determine the macroscopic effective modulus of SMAC as well as the stress characteristics of the fiber phase and interface phase of SMA. The findings demonstrate the significance of volume fraction and tensile pre-strain in stress transfer between the fiber phase and interface phase at high temperatures. The maximum axial stress in the fiber phase is 705.05 MPa when the SMA is fully austenitic and the pre-strain increases to 5%. At 10% volume fraction of SMA, the fiber phase's maximum axial stress can reach 1000 MPa. Ultimately, an experimental verification of the theoretical calculation method's accuracy for the effective modulus of SMAC lays the groundwork for the dynamic modeling of SMAC structures.

Fabrication of a MXene-based shape-memory hydrogel and its application in the wound repair of skin.

Wound dressings can generally complete hemostasis and provide temporary protection after skin damage. Herein, a MXene-based hydrogel was prepared from MXene, gelatin, poly(ethylene glycol)diacrylate (PEGDA) and N,N'-methylenebis(acrylamide) (HEAA) to prepare wound-dressing hydrogels for skin repair. HEAA and PEGDA crosslink polymerization formed the first layer of the network. Hydrogen bonds between MXene, PHEAA, and gelatin formed the second layer of the network. To make the hydrogel more suitable for skin repair, the mechanical properties of the hybrid hydrogel were adjusted. The MXene-based hydrogel could recover its original shape in 16 s upon immersion in water or for a few minutes under light irradiation. The obtained hydrogel showed good photothermal properties upon light irradiation (808 nm, 1 W cm-2) for 20 s, and its temperature on the surface could reach 86.4 °C. Due to its good photothermal properties, this MXene-based hydrogel was suitable for skin repair.

Distributed sensing along fibers for smart clothing.

Textile sensors transform our everyday clothing into a means to track movement and biosignals in a completely unobtrusive way. One major hindrance to the adoption of "smart" clothing is the difficulty encountered with connections and space when scaling up the number of sensors. There is a lack of research addressing a key limitation in wearable electronics: Connections between rigid and textile elements are often unreliable, and they require interfacing sensors in a way incompatible with textile mass production methods. We introduce a prototype garment, compact readout circuit, and algorithm to measure localized strain along multiple regions of a fiber. We use a helical auxetic yarn sensor with tunable sensitivity along its length to selectively respond to strain signals. We demonstrate distributed sensing in clothing, monitoring arm joint angles from a single continuous fiber. Compared to optical motion capture, we achieve around five degrees error in reconstructing shoulder, elbow, and wrist joint angles.

Electrospun fiber mats based on chitosan-carrageenan containing Malva sylvestris anthocyanins: Physic-mechanical, thermal, and barrier properties along with application as intelligent food packaging materials.

This study aimed to encapsulate Malva sylvestris extract (MSE) into chitosan-carrageenan (CH-KC) fibers using the electrospinning technique and monitor the freshness of silver carp fillets during the refrigerated storage conditions for 8 days. The CH-KC + MSE 4 % fiber mats were red at pH values lower than 3, purple at pH 4-6, dark blue at pH 7, green at pH 8-10, and brown at pH 11-12. The tensile strength, elongation at break, water vapor permeability, oxygen transmission rate, moisture content, and water solubility of fabricated fiber mats were 7.71-11.02 MPa, 13.12 %-30.00 %, 7.35-20.01 × 10-4 g mm/m2 h Pa, 3.81-8.23 cm3/m2 h, 15.74 %-27.34 %, and 3.90 %-7.56 %, respectively. Regarding the potential application of a fabricated indicator for freshness monitoring of silver carp fillets, total viable count, psychrotrophic bacterial count, pH, and total volatile basic nitrogen reached 8.91 log CFU/g, 8.03 log CFU/g, 8.10, and 40.18 mg N/100 g at the end of the study, respectively. Meanwhile, the CH-KC + MSE 4 % fiber mat color changed from white to green. These findings suggest that CH-KC + MSE 4 % fiber mats can be further utilized in the food industry to control the freshness of refrigerated silver carp fillets.

Development of smart packaging film incorporated with sodium alginate-chitosan quaternary ammonium salt nanocomplexes encapsulating anthocyanins for monitoring milk freshness.

This study focused on the preparation, functionality, and application of smart food packaging films based on polyvinyl alcohol (PVA) and anthocyanins (ACNs) -loaded sodium alginate-chitosan quaternary ammonium salt (HACC-SA) nanocomplexes. The average encapsulation rate of anthocyanins-loaded nanocomplexes reached 62.51 %, which improved the hydrophobicity and water vapor barrier of the PVA film. FTIR confirmed that the nanocomplexes were immobilized in the PVA film matrix by hydrogen bonding, which improved the mechanical properties of the film. The SEM and XRD results demonstrated that the HACC-SA-ACNs nanocomplexes were uniformly distributed in the film matrix and the crystallinity of PVA was decreased. The P/HACC-SA-ACNs film showed a significant response to buffers of pH 2-13 and high color stability after 21 days of storage compared to the P/ACNs film. Furthermore, the color of the composite film changed from purple to red as the milk freshness decreased during 72 h of milk freshness monitoring, indicating that the P/HACC-SA-ACNs films were suitable and promising for application as smart packaging materials.

Rational tuning of binding properties of pillar [5] arene-based sensing material by synergistic effect and its application for fluorescent turn-on detection of isoniazid and controlled reversible morphology.

Isoniazid (INH) is crucial in the treatment of tuberculosis; however, its overuse may induce significant gastrointestinal and hepatic side effects. On October 27, 2017, the International Agency for Research on Cancer, under the auspices of the World Health Organization, published a list of carcinogens for preliminary collation and reference. Isoniazid was categorized as a Group 3 carcinogen. The efficient detection of INH poses an important and challenging task. In this study, a "synergistic effect" is incorporated into the pillar (Yamagishi and Ogoshi, 2018) [5] arene-based macrocyclic host (DPA) by strategically attaching bis-p-hydroxybenzoic acid groups to the opposite ends of the pillar (Yamagishi and Ogoshi, 2018) [5] arene. This combination endows DPA with a reversible and selective fluorescence response to isoniazid. Additionally, DPA exhibits excellent analytical capabilities for isoniazid, including speed and selectivity, with a detection limit as low as 4.85 nM. Concurrently, DPA can self-assemble into a microsphere structure, which is convertible into micrometer-sized tubular structures through host-guest interactions with isoniazid. The introduction of a competitive guest, trimethylamine, enables the reversion to its microsphere structure. Consequently, this study presents an innovative and straightforward synthetic approach for smart materials that facilitates the reversible morphological transition between microspheres and microtubes in response to external chemical stimuli. This discovery provides a valuable strategy for designing "synergistic effects" in constructing trace-level isoniazid-responsive interfaces, with potential applications across various fields, such as controlled drug delivery.

Degrees of macrophage-facilitated healing in aneurysm occlusion devices.

Insufficient healing of aneurysms following treatment with vascular occlusion devices put patients at severe risk of fatal rupture. Therefore, promoting healing and not just occlusion is vital to enhance aneurysm healing. Following occlusion device implantation, healing is primarily orchestrated by macrophage immune cells, ending with fibroblasts depositing collagen to stabilize the aneurysm neck and dome, preventing rupture. Several modified occlusion devices are available currently on-market. Previous in vivo work demonstrated that modifications of occlusion devices with a shape memory polymer foam had enhanced aneurysm healing outcomes. To better understand cellular response to occlusion devices and improve aneurysm occlusion device design variables, we developed an in vitro assay to isolate prominent interactions between devices and key healing players: macrophages and fibroblasts. We used THP-1 monocyte derived macrophages and human dermal fibroblasts in our cell culture models. Macrophages were allowed device contact with on-market competitor aneurysm occlusion devices for up to 96 h, to allow for any spontaneous device-driven macrophage activation. Macrophage secreted factors were captured in the culture media, in response to device-specific activation. Fibroblasts were then exposed to device-conditioned macrophage media (with secreted factors alone), to determine if there were any device-induced changes in collagen secretion. Our in vitro studies were designed to test the direct effect of devices on macrophage activation, and the indirect effect of devices on collagen secretion by fibroblasts to promote aneurysm healing and stabilization. Over 96 h, macrophages displayed significant migration toward and interaction with all tested devices. As compared to other devices, shape memory polymer foams (SMM, Shape Memory Medical) induced significant changes in gene expression indicating a shift toward an anti-inflammatory pro-healing M2-like phenotype. Similarly, macrophages in contact with SMM devices secreted more vascular endothelial growth factor (VEGF) compared with other devices. Macrophage conditioned media from SMM-contacted macrophages actively promoted fibroblast secretion of collagen, comparable to amounts observed with exogenous stimulation via VEGF supplementation. Our data indicate that SMM devices may promote good aneurysm healing outcomes, because collagen production is an essential step to ultimately stabilize an aneurysm.

Solvent-free synthesis of biostable segmented polyurethane shape memory polymers for biomedical applications.

Biostable shape memory polymers that remain stable in physiological conditions are beneficial for user-defined shape recovery in response to a specific stimulus. For potential commercialization and biocompatibility considerations, biomaterial synthesis must be simple and scalable. Hence, a library of biostable and cytocompatible shape memory polymers with tunable thermomechanical properties based on hard segment content was synthesized using a solvent-free method. Polymer surface chemistry, thermomechanical and shape memory properties, and biostability were assessed. We also investigated the effects of processing methods on thermomechanical and shape memory properties. All polymers showed high glass transition temperatures (>50 °C), which indicates that their temporary shape could be preserved after implantation. Polymers also demonstrate high shape fixity (73-80%) and shape recovery (93-95%). Minimal mass loss (<5%) was observed in accelerated oxidative (20% H2O2) and hydrolytic (0.1 M NaOH) media. Additionally, minimal shape recovery (∼0%) occurred in programmed samples with higher hard segment content that were stored in degradation media. After 40 days of storage in media, programmed samples recovered their primary shapes upon heating to temperatures above their transition temperature. Annealing to above the polymer melting point and solvent casting of polymers improved shape memory and thermal properties. To enable their potential use as biomaterial scaffolds, fiber formation of synthesized polyurethanes was compared with those of samples synthesized using a previously reported solvent-based method. The new method provided polymers that can form fibrous scaffolds with improved mechanical and shape memory properties, which is attributed to the higher molecular weight and crystalline content of polymers synthesized using the new, solvent-free approach. These biostable segmented polyurethanes could be coupled with a range of components that respond to specific stimuli, such as enzymes, magnetic field, pH, or light, to enable a specific shape change response, which could be coupled with drug and/or bioactive material delivery in future work.

Using chitosan nanofibers to simultaneously improve the toughness and sensing performance of chitosan-based ionic conductive hydrogels.

Conductive hydrogels, especially polysaccharide-based ionic conductive hydrogels, have received increasing interest in the field of wearable sensors due to their similarity to human skin. Nevertheless, it is still a challenging task to simultaneously prepare a self-healed and adhesive conductive hydrogel with good toughness, temperature tolerance and high sensing performance, especially with high sensitivity and a low detection limit. Herein, we developed a new strategy to improve the toughness and sensing performance of a multifunctional conductive hydrogel by simultaneously using dissolved chitosan (CS) and solid chitosan nanofibers (CSFs) to induce the formation of hierarchical polymeric networks in the hydrogel. The tensile strength and elongation at break of the hydrogel could be improved from 70.3 kPa and 1005 % to 173.9 kPa and 1477 %, respectively, simply by introducing CSFs to the hydrogel, and its self-healing, adhesive and antibacterial properties were effectively retained. When serving as a resistive sensing material, the introduction of CSFs increased the gauge factor of the hydrogel-based strain sensor from 8.25 to 14.27. Moreover, the hydrogel-based strain sensor showed an ultralow detection limit of 0.2 %, excellent durability and stability (1000 cycles) and could be used to detect various human activities. In addition, the hydrogel prepared by using a water-glycerol binary solvent system showed temperature-tolerant performance and possessed adequate sensitivity when serving as a resistive sensing material. Therefore, this work provides a new way to prepare multifunctional conductive hydrogels with good toughness, sensing performance and temperature tolerance to expand the application range of hydrogel-based strain sensors.

A solid-phase fluorescence sensor for measuring chemical species in water.

In this study, the first of its kind, a solid-phase fluorescence sensing platform was developed to quantify contaminants in water. ZnO quantum dots (QDs) were combined with molecularly imprinted polymers (MIPs) to form fluorescence sensing materials. Solid sensing layers were formed via a straightforward spin-coating method, which demonstrated a strong attachment to the sensor substrate while maintaining the integrity of the sensing materials. The developed sensing platform comprised a portable fluorescence detector to measure fluorescence intensity, instead of traditional fluorescence spectroscopy. The solid sensing platform was first tested with 2,4-dichlorophenoxyacetic acid (2,4-D), demonstrating high sensitivity (0.0233) and a very strong correlation (0.98) between the target molecule concentration and sensor signal. Further, the sensing platform was successfully adapted to measure a substance with a different molecular mass and chemical structure, the algae toxin microcystin-LR (MCLR); this demonstrated the sensor's versatility in quantifying target molecules. Tap water samples spiked with MCLR were also used to test the sensor's practical application. Finally, the working mechanism of the sensing platform was established, and the key information for using the sensor to measure various contaminants was determined. With its high performance, broad applicability, and ease of use, the developed platform provides a suitable basis for lab-on-chip image-based sensing devices for environmental monitoring.

Hydrogels for Chemical Sensing and Biosensing.

The development and synthesis of hydrogels for chemical and biosensing are of great value. Hydrogels can be tailored to its own physical structure, chemical properties, biocompatibility, and sensitivity to external stimuli when being used in a specific environment. Herein, hydrogels and their applications in chemical and biosensing are mainly covered. In particular, it is focused on the manner in which hydrogels serve as sensing materials to a specific analyte. Different types of responsive hydrogels are hence introduced and summarized. Researchers can modify different chemical groups on the skeleton of the hydrogels, which make them as good chemical and biosensing materials. Hydrogels have great application potential for chemical and biosensing in the biomedical field and some emerging fields, such as wearable devices.

Smart Biomaterials in Biomedical Applications: Current Advances and Possible Future Directions.

Smart biomaterials with the capacity to alter their properties in response to an outside stimulus or from within the environment around them have picked up significant attention in the biomedical community. This is primarily due to the interest in their biomedical applications that may be anticipated from them in a considerable number of dynamic structures and devices. Shape-memory materials are some of these materials that have been exclusively used for these applications. They exhibit unique structural reconfiguration features they adapt as per the provided environmental conditions and can be designed for their enhanced biocompatibility. Numerous research initiatives have focused on these smart biocompatible materials over the last few decades to enhance their biomedical applications. Shape-memory materials play a significant role in this regard to meet new surgical and medical devices' requirements for special features and utility cases. Because of the favorable design variety, different biomedical shape-memory materials can be developed by modifying their chemical and physical behaviors to accommodate the desired requirements. In this review, recent advances and characteristics of smart biomaterials for biomedical applications are described. The authors also discuss about their clinical translations in tissue engineering, drug delivery, and medical devices.

Micropyramid Array Bimodal Electronic Skin for Intelligent Material and Surface Shape Perception Based on Capacitive Sensing.

Developing electronic skins (e-skins) that are comparable to or even beyond human tactile perception holds significant importance in advancing the process of intellectualization. In this context, a machine-learning-motivated micropyramid array bimodal (MAB) e-skin based on capacitive sensing is reported, which enables spatial mapping applications based on bimodal sensing (proximity and pressure) implemented via fringing and iontronic effects, such as contactless measurement of 3D objects and contact recognition of Braille letters. Benefiting from the iontronic effect and single-micropyramid structure, the MAB e-skin in pressure mode yields impressive features: a maximum sensitivity of 655.3 kPa-1 (below 0.5 kPa), a linear sensitivity of 327.9 kPa-1 (0.5-15 kPa), and an ultralow limit of detection of 0.2 Pa. With the assistance of multilayer perceptron and convolutional neural network, the MAB e-skin can accurately perceive 6 materials and 10 surface shapes based on the training and learning using the collected datasets from proximity and pressure modes, thus allowing it to achieve the precise perception of different objects within one proximity-pressure cycle. The development of this MAB e-skin opens a new avenue for robotic skin and the expansion of advanced applications.

Construction of Carbon Dots@LiCl-polyacrylamide with Humidity-Induced Ultralong Room-Temperature Phosphorescence to Fluorescence and Rigid-to-Flexible Transition Behavior.

The continuous advancement of luminescent materials has placed increasingly stringent requirements on dynamic color-tunable ultralong room-temperature phosphorescence (URTP) materials that can respond to external stimuli. Nevertheless, endowing URTP materials with stimuli-response-induced dynamic color tuning is a challenging task. This study introduces a carbon dots (CDs)@LiCl-polyacrylamide (PAM) polymer system that switches from URTP to fluorescence under humidity stimuli, accompanied by a transition from rigidity to flexibility. The obtained rigid CDs@LiCl-PAM exhibits ultralong green phosphorescence with a lifetime of 560 ms in the initial state. After absorbing moisture, it becomes flexible and its phosphorescence switches off. Moreover, the emission of the CDs@LiCl-PAM film depends on the excitation wavelength. This property can potentially used in multicolored luminescence applications and displays. Moreover, multicolor luminescent patterns can be constructed in situ using the water-absorption ability of the obtained thin film and the Förster resonance energy-transfer strategy. The proposed strategy is expected to promote the interdisciplinary development of intelligent information encryption, anti-counterfeiting, and smart flexible display materials.

Self-Healing, Laminated, and Low Resistance NH3 Sensor Based on 6,6',6″-(Nitrilotris(benzene-4,1-diyl))tris(5-phenylpyrazine-2,3-dicarbonitrile) Sensing Material Operating at Room Temperature.

With the rapid development of the concept of the Internet of Things (IoT), gas sensors with the function of simulating the human sense of smell became irreplaceable as a key element. Among them, ammonia (NH3) sensors played an important role in respiration tests, environmental monitoring, safety, and other fields. However, the fabrication of the high-performance device with high stability and resistance to mechanical damages was still a challenge. In this work, polyurethane (PU) with excellent self-healing ability was applied as the substrate, and the sensor was designed from new sensitive material design and device structure optimization, through applying the organic molecule with groups which could absorb NH3 and the laminated structure to shorten the electronic transmission path to achieve a low resistance state and favorable sensing properties. Accordingly, a room temperature flexible NH3 sensor based on 6,6',6″-(nitrilotris(benzene-4,1-diyl))tris(5-phenylpyrazine-2,3-dicarbonitrile) (TPA-3DCNPZ) was successfully developed. The device could self-heal by means of a thermal evaporation assisted method. It exhibited a detection limit of 1 ppm at 98% relative humidity (RH), as well as great stability, selectivity, bending flexibility, and self-healing properties. The improved NH3 sensing performance under high RH was further investigated by complex impedance plots (CIPs) and density functional theory (DFT), attributing to the enhanced adsorption of NH3. The TPA-3DCNPZ based NH3 sensors proved to have great potential for application on simulated exhaled breath to determine the severity of kidney diseases and the progress of treatment. This work also provided new ideas for the construction of high-performance room temperature NH3 sensors.

Physiochemical and mechanical characterisation of orthodontic 3D printed aligner material made of shape memory polymers (4D aligner material).

OBJECTIVES: To conduct a physiochemical and mechanical material analysis on 3D printed shape-memory aligners in comparison to thermoformed aligners. MATERIALS AND METHODS: Four materials were examined, including three thermoformed materials: CA Pro (CP), Zendura A (ZA), Zendura FLX (ZF), and one 3D printed material: Tera Harz (TC-85). Rectangular strips measuring 50 × 10 × 0.5 mm were produced from each material. Five tests were conducted, including differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), shape recovery tests, three-points bending (3 PB), and Vickers surface microhardness (VH). RESULTS: DSC recorded glass transition temperatures (Tg) at 79.9 °C for CP, 92.2 °C for ZA, 107.1 °C for ZF, and 42.3 °C for TC-85. In DMA analysis at 20-45 °C, a prominent decrease in storage modulus was observed, exclusively for TC-85, as the temperature increased. Notably, within the temperature range of 30-45 °C, TC-85 exhibited substantial shape recovery after 10 min, reaching up to 86.1 %, while thermoformed materials showed minimal recovery (1.5-2.9 %). In 3 PB test (at 30, 37, 45 °C), ZA demonstrated the highest force at 2 mm bending, while TC-85 exhibited the lowest. Regarding VH at room temperature, there was a significant decrease for both ZA and ZF after thermoforming. ZA had the highest hardness, followed by ZF and TC-85, with CP showing the lowest values. CONCLUSIONS: TC-85 demonstrates exceptional shape memory at oral temperature, improving adaptation, reducing force decay, and enabling, together with its higher flexibility, extensive tooth movement per step. Additionally, it maintains microhardness similar to thermoformed sheets, ensuring the durability and effectiveness of dental aligners. CLINICAL RELEVANCE: The 3D printed aligner material with shape memory characteristics (4D aligner) has revolutionized the orthodontic aligner field. It showed mechanical properties more suitable for orthodontic treatment than thermoforming materials. Additionally, it offers enhanced control over aligner design and thickness, while optimizing the overall workflow. It also minimizes material wastage, and reduces production expenses.

Hierarchical Mechanical Transduction of Precision-Engineered DNA Hydrogels with Sacrificial Bonds.

Engineering the response to external signals in mechanically switchable hydrogels is important to promote smart materials applications. However, comparably little attention has focused on embedded precision mechanisms for autonomous nonlinear response in mechanical profiles in hydrogels, and we lack understanding of how the behavior from the molecular scale transduces to the macroscale. Here, we design a nonlinear stress-strain response into hydrogels by engineering sacrificial DNA hairpin loops into model network hydrogels formed from star-shaped building blocks. We characterize the force-extension response of single DNA hairpins and are able to describe how the specific topology influences the nonlinear mechanical behavior at different length scales. For this purpose, we utilize force spectroscopy as well as microscopic and macroscopic deformation tests. This study contributes to a better understanding of designing nonlinear strain-adaptive features into hydrogel materials.

From Static to Dynamic: Smart Materials Pioneering Additive Manufacturing in Regenerative Medicine.

The emerging field of regenerative medicine holds immense promise for addressing complex tissue and organ regeneration challenges. Central to its advancement is the evolution of additive manufacturing techniques, which have transcended static constructs to embrace dynamic, biomimetic solutions. This manuscript explores the pivotal role of smart materials in this transformative journey, where materials are endowed with dynamic responsiveness to biological cues and environmental changes. By delving into the innovative integration of smart materials, such as shape memory polymers and stimulus-responsive hydrogels, into additive manufacturing processes, this research illuminates the potential to engineer tissue constructs with unparalleled biomimicry. From dynamically adapting scaffolds that mimic the mechanical behavior of native tissues to drug delivery systems that respond to physiological cues, the convergence of smart materials and additive manufacturing heralds a new era in regenerative medicine. This manuscript presents an insightful overview of recent advancements, challenges, and future prospects, underscoring the pivotal role of smart materials as pioneers in shaping the dynamic landscape of regenerative medicine and heralding a future where tissue engineering is propelled beyond static constructs towards biomimetic, responsive, and regenerative solutions.

A review of recent advances in biomedical applications of smart cellulose-based hydrogels.

In biomedical engineering, smart materials act as media to communicate physiological signals inspired by environmentally responsive stimuli with outer indicators for timely scrutiny and precise therapy. Various physical and chemical processes are applied in the design of specific smart functions. Hydrogels are polymeric networks consisting of hydrophilic chains and chemical groups and they have contributed their unique features in biomedical application as one of the most used smart materials. Numerous raw materials can form hydrogels, in which cellulose and its derivatives have been extensively exploited in biomedicine due to their high hydrophilicity, availability, renewability, biodegradability, biocompatibility, and multifunctional reactivity. This review collates cellulose-based hydrogels and their extensive applications in the biomedical domain, specifically benefiting from the "SMART" concept in their design, synthesis and device assembly. The first section discusses the physical and chemical crosslinking and electrospinning techniques used in the fabrication of smart cellulose-based hydrogels. The second section describes the performance of these hydrogels, and the final section is a comprehensive discussion of their biomedical applications.

How Smart are Smart Materials? A Conceptual and Ethical Analysis of Smart Lifelike Materials for the Design of Regenerative Valve Implants.

It may soon become possible not just to replace, but to re-grow healthy tissues after injury or disease, because of innovations in the field of Regenerative Medicine. One particularly promising innovation is a regenerative valve implant to treat people with heart valve disease. These implants are fabricated from so-called 'smart', 'lifelike' materials. Implanted inside a heart, these implants stimulate re-growth of a healthy, living heart valve. While the technological development advances, the ethical implications of this new technology are still unclear and a clear conceptual understanding of the notions 'smart' and 'lifelike' is currently lacking. In this paper, we explore the conceptual and ethical implications of the development of smart lifelike materials for the design of regenerative implants, by analysing heart valve implants as a showcase. In our conceptual analysis, we show that the materials are considered 'smart' because they can communicate with human tissues, and 'lifelike' because they are structurally similar to these tissues. This shows that regenerative valve implants become intimately integrated in the living tissues of the human body. As such, they manifest the ontological entanglement of body and technology. In our ethical analysis, we argue this is ethically significant in at least two ways: It exacerbates the irreversibility of the implantation procedure, and it might affect the embodied experience of the implant recipient. With our conceptual and ethical analysis, we aim to contribute to responsible development of smart lifelike materials and regenerative implants.