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Plastics are widely used materials that pose an ecological challenge because their wastes are difficult to degrade. Embedding enzymes and biomachinery within polymers could enable the biodegradation and disposal of plastics. However, enzymes rarely function under conditions suitable for polymer processing. Here, we report degradable living plastics by harnessing synthetic biology and polymer engineering. We engineered Bacillus subtilis spores harboring the gene circuit for the xylose-inducible secretory expression of Burkholderia cepacia lipase (BC-lipase). The spores that were resilient to stresses during material processing were mixed with poly(caprolactone) to produce living plastics in various formats. Spore incorporation did not compromise the physical properties of the materials. Spore recovery was triggered by eroding the plastic surface, after which the BC-lipase released by the germinated cells caused near-complete depolymerization of the polymer matrix. This study showcases a method for fabricating green plastics that can function when the spores are latent and decay when the spores are activated and sheds light on the development of materials for sustainability.
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Solar-driven interfacial evaporation (SIE) is emerging as an energy-efficient technology to alleviate the global water shortages. However, there is a fatal disadvantage in using SIE, that is, the volatile organic compounds (VOCs) widely present in feedwater would concurrently evaporate and transport in distilled water, which threatens the water safety. Photocatalysis is a sustainable technology for pollution control, and after years of development, it has become a mature method. Considering the restriction by the insufficient reaction of the permeating VOCs on the two-dimensional (2D) light-available interface of conventional materials, a 3D photocatalytic approach can be established to boost VOC rejection for photothermal evaporation. In the present work, a light-permeable solar evaporator with 3D photocatalytic sites is constructed by a porous sponge decorated with BiOBrI nanosheets with oxygen-rich vacancies. The 3D microchannels in the evaporator provide a light-permeable path with the deepest irradiation depth of about 580 µm, and the reactive interface is increased by tens of times compared with the traditional 2D membrane, resulting in suppression of VOC remnants in distilled water by around four orders of magnitude. When evaporating river water containing 5 mg L-1 extra added phenol, no phenol residues (below 0.001 mg/L) were detected in the produced freshwater. This development is believed to provide a powerful strategy to resolve the VOC bottleneck of SIE.
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Compostos Orgânicos Voláteis , Purificação da Água , Membranas , Luz Solar , Água/química , Purificação da Água/métodosRESUMO
Polymer doping is a significant approach to precisely control nucleation and crystal growth of perovskites and enhance electronic quality in perovskite solar cells (PSC) prepared in air. Here, a brand-new self-healing polysiloxane (SHP) with dynamic 2,6-pyridinedicarboxamide (PDCA) coordination units and plenty of hydrogen bonds was designed and incorporated into perovskite films. PDCA units, showing strong intermolecular Pb2+ -Namido , I- -Npyridyl , and Pb2+ -Oamido coordination interactions, were expected to enhance crystallinity and passivate the grain boundary. In addition, abundant hydrogen bonds in SHP afforded the self-healing of cracks at grain boundaries for fatigue PSCs. Significantly, the doped device demonstrated a champion efficiency of 19.50 % with inconspicuous hysteresis, almost rivaling those achieved in control atmosphere. This strategy of heterocyclic-based macromolecular doping in PSCs will pave a way for realizing efficient and durable crystalline semiconductors.
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Solar distillation through photothermal evaporators has approached solar light energy (E1) limit under no solar concentration but still suffers from modest vapor and clean water production. Herein, a nature-inspired low-tortuosity three-dimensional (3D) evaporator is demonstrated to significantly improve water production. The solar evaporator, prepared from polypyrrole-modified maize straw (PMS), had upright vascular structures enabling high water lifting and horizontal microgaps facilitating broad water distribution to the out-surface. Consequently, this novel PMS evaporator dramatically enhanced the utilization of the solar heat energy stored in the environment (E2) for promoting evaporation. The maximum vapor generation rate of a single PMS respectively increases 2.5 and 6 times compared with the conventional 3D evaporators and the planar evaporators of an identical occupied area. Consequently, a scaled-up PMS array achieved a state-of-the-art vapor generation rate of 3.0 L m-2 h-1 (LMH) under a simulated condition and a record-high clean water production of 2.2 LMH for actual seawater desalination under natural conditions (1 sun intensity). This breakthrough reveals great potentials for cost-effective freshwater production as well as the rational design of high-performance photothermal evaporators for solar distillation.
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Destilação , Purificação da Água , Polímeros , Pirróis , ÁguaRESUMO
Solar distillation is emerging as a robust and energy-effective tool for water purification and freshwater production. However, many water sources contain harmful volatile organic compounds (VOCs), which can evaporate through the photothermal evaporators and be collected together with distilled water, or even be enriched in the distilled water. In view of the penetration of volatile organic compounds, herein, we rationally demonstrate a dual-scale porous, photothermal/photocatalytic, flexible membrane for intercepting volatile organic compounds during solar distillation, which is based on a mesoporous oxygen-vacancy-rich TiO2-x nanofibrous membrane (m-TiO2-x NFM). The dual-scale porous structure was constructed by micrometer-sized interconnected tortuous pores formed by the accumulation of m-TiO2-x nanofibers and nanometer-sized pores in the m-TiO2-x individual nanofibers. Consequently, the membrane can sustainably in situ intercept VOCs by providing more photocatalytic reactive sites for collision (mainly by mesopores) and longer tortuous channels for prolonging VOC retention (mainly by micrometer-sized pores); thus, it results in less than 5% of phenol residual in distilled water. As a proof of concept, when the m-TiO2-x NFM is employed to purify practical river water in an evaporation prototype under real solar irradiation, complex volatile natural organic contaminants can be effectively intercepted and the produced distilled water meets the drinking water standards of China. This development will promote the application prospects of solar distillation.
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Nanofibras , Purificação da Água , China , Destilação , Luz Solar , TitânioRESUMO
Herein, we report a de novo chemical design of supramolecular polymer materials (SPMs-1-3) by condensation polymerization, consisting of (i) soft polymeric chains (polytetramethylene glycol and tetraethylene glycol) and (ii) strong and reversible quadruple H-bonding cross-linkers (from 0 to 30 mol %). The former contributes to the formation of the soft domain of the SPMs, and the latter furnishes the SPMs with desirable mechanical properties, thereby producing soft, stretchable, yet tough elastomers. The resulting SPM-2 was observed to be highly stretchable (up to 17â¯000% strain), tough (fracture energy â¼30â¯000 J/m2), and self-healing, which are highly desirable properties and are superior to previously reported elastomers and tough hydrogels. Furthermore, a gold, thin film electrode deposited on this SPM substrate retains its conductivity and combines high stretchability (â¼400%), fracture/notch insensitivity, self-healing, and good interfacial adhesion with the gold film. Again, these properties are all highly complementary to commonly used polydimethylsiloxane-based thin film metal electrodes. Last, we proceed to demonstrate the practical utility of our fabricated electrode via both in vivo and in vitro measurements of electromyography signals. This fundamental understanding obtained from the investigation of these SPMs will facilitate the progress of intelligent soft materials and flexible electronics.
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Reagentes de Ligações Cruzadas/síntese química , Polímeros/síntese química , Reagentes de Ligações Cruzadas/química , Eletrodos , Ligação de Hidrogênio , Substâncias Macromoleculares/síntese química , Substâncias Macromoleculares/química , Conformação Molecular , Polímeros/químicaRESUMO
Wearable healthcare presents exciting opportunities for continuous, real-time, and noninvasive monitoring of health status. Even though electrochemical and optical sensing have already made great advances, there is still an urgent demand for alternative signal transformation in terms of miniaturization, wearability, conformability, and stretchability. Mechano-based transductive sensing, referred to the efficient transformation of biosignals into measureable mechanical signals, is claimed to exhibit the aforementioned desirable properties, and ultrasensitivity. In this Concept, a focus on pressure, strain, deflection, and swelling transductive principles based on micro-/nanostructures for wearable healthcare is presented. Special attention is paid to biophysical sensors based on pressure/strain, and biochemical sensors based on microfluidic pressure, microcantilever, and photonic crystals. There are still many challenges to be confronted in terms of sample collection, miniaturization, and wireless data readout. With continuing efforts toward solving those problems, it is anticipated that mechano-based transduction will provide an accessible route for multimode wearable healthcare systems integrated with physical, electrophysiological, and biochemical sensors.
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Técnicas Biossensoriais/métodos , Dispositivos Eletrônicos Vestíveis , Tecnologia sem FioRESUMO
Mesoporous integrated TiO2 spheres composed of numerous orderly arranged nanocrystals with a reduced lattice-lattice interface connection, display an almost four times longer electron lifetime (350 ps) than the randomly aggregated nanoparticles (80 ps), and hence enhance the corresponding photocatalytic H2 and O2 generation.
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The fundamental understanding of the relationship between the nanostructure of an electrode and its electrochemical performance is crucial for achieving high-performance lithium-ion batteries (LIBs). In this work, the relationship between the nanotubular aspect ratio and electrochemical performance of LIBs is elucidated for the first time. The stirring hydrothermal method was used to control the aspect ratio of viscous titanate nanotubes, which were used to fabricate additive-free TiO2 -based electrode materials. We found that the battery performance at high charging/discharging rates is dramatically boosted when the aspect ratio is increased, due to the optimization of electronic/ionic transport properties within the electrode materials. The proof-of-concept LIBs comprising nanotubes with an aspect ratio of 265 can retain more than 86 % of their initial capacity over 6000 cycles at a high rate of 30 C. Such devices with supercapacitor-like rate performance and battery-like capacity herald a new paradigm for energy storage systems.
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Fontes de Energia Elétrica , Lítio/química , Nanotubos/química , Titânio/química , Eletrodos , Nanotubos/ultraestruturaRESUMO
Foodborne carbon dots (CDs) are generally produced during cooking and exist in food items. Generally, CDs are regarded as nontoxic materials, but several studies have gradually confirmed the cytotoxicity of CDs, such as oxidative stress, reduced cellular activity, apoptosis, etc. However, studies focusing on the health effects of long-term intake of food-borne CDs are scarce, especially in populations susceptible to metabolic disease. In this study, we reported that CDs in self-brewing beer had no effect on glucose metabolism in CHOW-fed mice but exacerbated high-fat-diet (HFD)-induced glucose metabolism disorders via the gut-liver axis. Chronic exposure to foodborne CDs increased fasting glucose levels and exacerbated liver and intestinal barrier damage in HFD-fed mice. The 16s rRNA sequencing analysis revealed that CDs significantly altered the gut microbiota composition and promoted lipopolysaccharide (LPS) synthesis-related KEGG pathways (superpathway of (Kdo)2-lipid A, Kdo transfer to lipid IVA Ill (Chlamydia), lipid IVA biosynthesis, and so on) in HFD-fed mice. Mechanically, CD exposure increased the abundance of Gram-negative bacteria (Proteobacteria and Desulfovibrionaceae), thus producing excessive endotoxin-LPS, and then LPS was transferred by the blood circulation to the liver due to the damaged intestinal barrier. In the liver, LPS promoted TLR4/NF-κB/P38 MAPK signaling, thus enhancing systemic inflammation and exacerbating HFD-induced insulin resistance. However, pretreating mice with antibiotics eliminated these effects, indicating a key role for gut microbiota in CDs exacerbating glucose metabolism disorders in HFD-fed mice. The finding herein provides new insight into the potential health risk of foodborne nanoparticles in susceptible populations by disturbing the gut-liver axis.
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Transtornos do Metabolismo de Glucose , Lipopolissacarídeos , Animais , Camundongos , Lipopolissacarídeos/metabolismo , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Fígado/metabolismo , Homeostase , Glucose/metabolismo , Dieta , Camundongos Endogâmicos C57BLRESUMO
Bioelectronics, which converges biology and electronics, has attracted great attention due to their vital applications in human-machine interfaces. While traditional bioelectronic devices utilize nonliving organic and/or inorganic materials to achieve flexibility and stretchability, a biological mismatch is often encountered because human tissues are characterized not only by softness and stretchability but also by biodynamic and adaptive properties. Recently, a notable paradigm shift has emerged in bioelectronics, where living cells, and even viruses, modified via gene editing within synthetic biology, are used as core components in a new hybrid electronics paradigm. These devices are defined as "living synthelectronics," and they offer enhanced potential for interfacing with human tissues at informational and substance exchange levels. In this Perspective, the recent advances in living synthelectronics are summarized. First, opportunities brought to electronics by synthetic biology are briefly introduced. Then, strategic approaches to designing and making electronic devices using living cells/viruses as the building blocks, sensing components, or power sources are reviewed. Finally, the challenges faced by living synthelectronics are raised. It is believed that this paradigm shift will significantly contribute to the real integration of bioelectronics with human tissues.
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Eletrônica , Biologia Sintética , Biologia Sintética/métodos , Humanos , Edição de Genes , Animais , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodosRESUMO
A gold nanotip array platform with a combination of ultrasensitive electrochemical sensing and spectroscopic monitoring capability is reported. Adenosine triphosphate is detected down to 1 pM according to the impedance changes in response to aptamer-specific binding. Furthermore, the local molecular information can be monitored at the individual plasmonic nanotips, and hence provide the capability for a better understanding of complex biological processes.
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Técnicas Eletroquímicas/instrumentação , Ouro/química , Nanotecnologia/instrumentação , Análise Espectral Raman , Trifosfato de Adenosina/análise , DNA/química , Dimetilpolisiloxanos/química , Azul de Metileno/químicaRESUMO
Biopharmaceuticals including protein therapeutics, engineered protein-based vaccines and monoclonal antibodies, are currently the mainstay products of the biotechnology industry. However, the need for specialized equipment and refrigeration during production and distribution poses challenges for the delivery of these technologies to the field and low-resource area. With the development of synthetic biology, multiple studies rewire the cell-free system or living cells to impact the portable, on-site and on-demand manufacturing of biomolecules. Here, we review these efforts and suggest future directions.
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Liquid metal (especially eutectic gallium indium, EGaIn) nanoparticle inks overcome the poor wettability of high surface tension EGaIn to elastomer substrates and show great potential in soft electronics. Normally, a sintering strategy is required to break the oxide shells of the EGaIn nanoparticles (EGaIn NPs) to achieve conductive paths. Herein, for the first time, thermal-sinterable EGaIn NP inks are prepared by introducing thermal expansion microspheres (TEMs) into EGaIn NP solution. Through the mechanical pressure induced by the expansion of the heated TEMs, the printed EGaIn NPs can be sintered into electrically conductive paths to achieve highly stretchable bioelectrode arrays, which exhibit giant electromechanical performance (up to 680% strain), good cyclic stability (over 2 × 104 cycles), and stable conductivity after high-speed rotation (6000 rpm). Simultaneously, the recording sites are hermetically sealed by ionic elastomer layers, ensuring the complete leakage-free property of EGaIn and reducing the electrochemical impedance of the electrodes (891.16 Ω at 1 kHz). The bioelectrode is successfully applied to monitor dynamic electromyographic signals. The sintering strategy overcomes the disadvantages of the traditional sintering strategies, such as leakage of EGaIn, reformation of large EGaIn droplets, and low throughput, which promotes the application of EGaIn in soft electronics.
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Tinta , Nanopartículas , Elastômeros , Condutividade Elétrica , Impedância ElétricaRESUMO
As an emerging functional material, liquid metal-hydrogel composites exhibit excellent biosafety, high electrical conductivity, tunable mechanical properties and good adhesion, thus providing a unique platform for a wide range of flexible electronics applications such as wearable devices, medical devices, actuators, and energy conversion devices. Through different composite methods, liquid metals can be integrated into hydrogel matrices to form multifunctional composite material systems, which further expands the application range of hydrogels. In this paper, we provide a brief overview of the two materials: hydrogels and liquid metals, and discuss the synthesis method of liquid metal-hydrogel composites, focusing on the improvement of the performance of hydrogel materials by liquid metals. In addition, we summarize the research progress of liquid metal-hydrogel composites in the field of flexible electronics, pointing out the current challenges and future prospects of this material.
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Flexible piezoresistive tactile sensors are widely used in wearable electronic devices because of their ability to detect mechanical stimuli. However, achieving high sensitivity and low hysteresis over a broad detection range remains a challenge with current piezoresistive tactile sensors. To address these obstacles, we designed elastomeric micropyramid arrays with different heights to redistribute the strain on the electrode. Furthermore, we mixed single-walled carbon nanotubes in the elastomeric micropyramids to compensate for the conductivity loss caused by random cracks in the gold film and increase the adhesion strength between the gold film (deposited on the pyramid surface) and the elastomer. Thus, the energy loss of the sensor during deformation and hysteresis (â¼2.52%) was effectively reduced. Therefore, under the synactic effects of the percolation effect, tunnel effect, and multistage strain distribution, the as-prepared sensor exhibited a high sensitivity (1.28 × 106 kPa-1) and a broad detection range (4.51-54837.06 Pa). The sensitivity was considerably higher than those of most flexible pressure sensors with a microstructure design. As a proof of concept, the sensors were successfully applied in the fields of health monitoring and human-machine interaction.
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Reducing the swelling of tissue-adhesive hydrogels is crucial for maintaining stable tissue adhesion and inhibiting tissue inflammation. However, reported strategies for reducing swelling always result in a simultaneous decrease in the tissue adhesive strength of the hydrogel. Furthermore, once the covalent bonds break in the currently reported hydrogels, they cannot be rebuilt, and the hydrogel loses its tissue adhesive ability. In this work, a nonswelling hydrogel (named as "PAACP") possessing regenerable high tissue adhesion is synthesized by copolymerizing and crosslinking poly(vinyl butyral) with acrylic acid, gelatin, and chitosan-grafted N-acetyl-l-cysteine. The tissue adhesive strength of the obtained PAACP reaches 211.4 kPa, which is approximately ten times higher than that of the reported nonswelling hydrogels, and the hydrogel can be reused for multiple cycles. The as-prepared hydrogel shows great potential in soft bioelectronics, as muscle fatigue is successfully monitored via the electrode array and strain sensor integrated on PAACP substrates. The success of these bioelectronics offers potential applicability in the long-term diagnosis of muscle-related health conditions and prosthetic manipulations.
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Quitosana , Adesivos Teciduais , Adesivos Teciduais/química , Hidrogéis/química , Quitosana/química , Gelatina/químicaRESUMO
Bacterial infections and multiple encrustations are life-threatening complications in patients implanted with urological devices. Limited by time-consuming procedures and substrate dependence, it is difficult to simultaneously prevent the aforementioned complications. Herein, is reported the design of a salt-triggered chondroitin sulfate complex (CS/Si-N+ ) coating with adaptive dissociation, which realizes the dual functions of antibacterial and anti-multiple encrustations in urological devices with arbitrary shapes. The existence of covalent interactions between the complex and the interface ensures the formation of a robust coating, especially in harsh environments. Benefiting from the adaptive dissociation of the ion pairs in the CS/Si-N+ coating in urine electrolytes, the exposed ion groups and enhanced hydrophilicity are more conducive to the inhibition of bacterial infection and multiple encrustations simultaneously. The coating exhibits broad-spectrum bactericidal effects. As a proof of concept, in a simulated metabolic encrustation model, the coating exhibits significant advantages in resisting calcium oxalate encrustation, with a reduction in the calcium content by over 90%. In addition, this non-leachable all-in-one coating shows good biocompatibility in a pig in vivo model. Such a coating strategy is expected to be a practical approach for preventing urological medical device-related complications.
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Antibacterianos , Próteses e Implantes , Suínos , Animais , Antibacterianos/farmacologia , Oxalato de Cálcio/urina , Biofilmes , CristalizaçãoRESUMO
Flexible electrode array, a new-generation neural microelectrode, is a crucial tool for information exchange between living tissues and external electronics. Till date, advances in flexible neural microelectrodes are limited because of their high impedance and poor mechanical consistency at tissue interfaces. Herein, a highly sensitive and omnidirectionally stretchable polymeric electrode array (PEA) is introduced. Micropyramid-nanowire composite structures are constructed to increase the effective surface area of PEA, achieving an exponential reduction in impedance compared with gold (Au) and flat polypyrrole electrodes. Moreover, for the first time, a suspended umbrella structure to enable PEA with omnidirectional stretchability of up to ≈20% is designed. The PEA can withstand 1000 cycles of mechanical loads without decrease in performance. As a proof of concept, PEA is conformally attached to a rat heart and tibialis anterior muscle, and electrophysiological signals (electrocardiogram and electromyogram) of the rat are successfully recorded. This strategy provides a new perspective toward highly sensitive and omnidirectionally stretchable PEA that can facilitate the practical application of neural electrodes.
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Polímeros , Pirróis , Ratos , Animais , Microeletrodos , Músculo Esquelético , Impedância ElétricaRESUMO
Congenital Muscular Torticollis (CMT) is a neuromuscular disease in children, which leads to exacerbation of postural deformity and neck muscle dysfunction with age. Towards facilitating functional assessment of neuromuscular disease in children, topographic electromyography (EMG) maps enabled by flexible and stretchable surface EMG (sEMG) electrode arrays are used to evaluate the neck myoelectric activities in this study. Customed flexible and stretchable sEMG electrode arrays with 84 electrodes were utilized to record sEMG in all subjects during neck motion tasks. Clinical parameter assessments including the cervical range of motion (ROM), sonograms of the sternocleidomastoid (SCM), and corresponding histological analysis were also performed to evaluate the CMT. The muscle activation patterns of neck myoelectric activities between the CMT patients and the healthy subjects were asymmetric during different neck motion tasks. The CMT patients presented significantly lower values in spatial features of two-dimensional (2D) correlation coefficient, left/right energy ratio, and left/right energy difference (p < 0.001). The 2D correlation coefficient of activation patterns of neck rotation and extension in CMT patients significantly correlated with clinical parameter assessments (p < 0.05). The findings suggest that the spatial features of muscle activation patterns based on the sEMG electrode arrays can be utilized to evaluate the CMT. The flexible and stretchable sEMG electrode array is promising to facilitate the functional evaluation and treatment strategies for children with neuromuscular disease.