Neuro-perceptive discrimination on fabric tactile stimulation by Electroencephalographic (EEG) spectra

The precise evaluation of sensory perceptions during fabric-skin interactions is still poorly understood in neuroscience. This study aims to investigate the cortical sensory response to fabric stimuli with different textiles by Electroencephalographic (EEG) spectral intensities, and evaluate the relationships between EEG frequency bands, traditional subjective questionnaires, and the materials' physical properties. Twelve healthy adult participants were recruited to test three fabrics with different textile compositions of 1) cotton, 2) nylon, and 3) polyester and wool. The physical properties of the fabrics were quantitatively evaluated by a Fabric Touch Tester (FTT). Subjects were invited to rate the sensory perception of the fabric samples via a subjective questionnaire and objective EEG recording. Significant differences in the EEG relative spectral power of Theta and Gamma bands were acquired in response to the different fabric stimuli (P<0.05). The Theta and Gamma powers demonstrated a significant correlation with the most of the subjective sensations evaluated by questionnaire and the fabrics' physical properties by FTT (P<0.05). The EEG spectral analysis could feasibly be used for the discrimination of fabric stimuli with different textile compositions and further indicates sensory perceptions during fabric stimulation. This finding may provide evidence for further exploratory research of sensory perceptions via EEG spectral analysis, which could be applied to the study of brain generators of skin tactility in future prostheses and the automatic detection of sensory perception in industries.

Polymorphic calcium alginate microfibers assembled using a programmable microfluidic field for cell regulation

Effectively guiding and accurately controlling cell adhesion and growth on the surfaces of specific morphological materials are key issues and hot research topics for optimizing biomaterials. Herein, novel polymorphic alginate microfibers formed through microfluidic spinning technology in a single microchip are presented. Through programming the flow and reaction kinetics in microchannels, other than self-modified micromorphic channel geometry, polymorphic microfibers with precisely tuned curvature-adjustable morphology can be obtained. Finite element (FE) simulations of the flow field (unidirectional fluid-solid coupling) proved the efficacy of the proposed control strategy. Moreover, the specific disordered-ordered cell arrangements showed a linear relationship between bioinspired alginate microfibers with different curvatures and the orientation angle of L929 cells, and diversified growth morphologies, including oblate ellipse, star, tree and strip shapes, occurred on the customizable interface curvature of the calcium alginate microfibers, providing a paradigm for using specific structured natural biomedical materials for cell regulation. This work represents a new design concept for manufacturing polymorphic fibrous biomedical materials through a unique marriage of the fields of green chemistry, hydromechanics, and biomaterials, which should be very useful for guiding the controllable construction of alginate materials for use in structural materials for biomedical and engineering purposes.

Growing Poly(norepinephrine) Layer over Individual Nanoparticles To Boost Hybrid Perovskite Photocatalysts

To address the poor stability of lead halide perovskite nanoparticles (NPs), monodisperse methylammonium lead bromide (MAPbBr₃, M-PE) NPs were successfully encapsulated with a thin layer (10 nm) of poly(norepinephrine) (PNE) by in situ polymerization. The PNE layer endowed M-PE NPs with high structural stability against severe environmental conditions. Furthermore, the chemical interaction between M-PE and PNE facilitates the construction of the core@shell composite, as well as contributes to the enhanced light-harvesting capacity and improved photoelectronic conversion efficiency in photocatalytic activity. The encapsulated NP M-PE@PNE with a band gap of 2.04 eV degraded the organic pollutant of malachite green by 81% in less than 2 h under visible light, which was 4.5 times higher than pristine M-PE NPs. This work provides a practical approach to stabilize and boost the MAPbX₃ photocatalyst and carries enormous potential in wide engineering applications.

Simultaneous fire safety enhancement and mechanical reinforcement of poly(lactic acid) biocomposites with hexaphenyl (nitrilotris(ethane-2,1-diyl))tris(phosphoramidate)

Poly(lactic acid) (PLA) is an important bioplastic polymer with wide engineering applications, but has relatively low tensile strength and high susceptibility to flames. This manuscript reports the synthesis of a new cyclo-phosphorus-nitrogen flame retardant (FR) - hexaphenyl (nitrilotris(ethane-2,1-diyl))tris(phosphoramidate) (HNETP) for concurrent FR and tensile strength enhancement. ¹H, ¹³C Nuclear Magnetic Resonance and Fourier Transform Infra-red spectra showed that HNETP was successfully synthesized. The FR properties of PLA/HNETP composites were investigated, and the peak heat release rate (PHRR) reduced by ˜ 51.3%, total heat released (THR) ˜ 43.1%, and carbon monoxide (CO) production by ˜ 46.5% with 3 wt% HNETP loading. The fire performance index increased by ˜ 65.8%, while the fire growth index decreased by ˜ 56.7%. The tensile strength and the Young's Modulus improved to ˜ 67.4 and ˜ 87.8% respectively. A significant increase in limiting oxygen index (LOI) (32.5%) was attained with a V-0 rating in the vertical burning test. TG-IR study showed considerable reduction in pyrolysis gaseous products by the PLA/HNETP composites compared to PLA. Insignificant changes were observed in the glass transition and the melting temperature of PLA and PLA/HNETP biocomposites.

Integration of Metal-Organic Frameworks on Protective Layers for Destruction of Nerve Agents under Relevant Conditions

Metal-organic frameworks (MOFs) are promising candidates for the catalytic hydrolysis of nerve agents and their simulants. Though highly efficient, bulk water and volatile bases are often required for hydrolysis with these MOF catalysts, preventing real-world implementation. Herein we report a generalizable and scalable approach for integrating MOFs and non-volatile polymeric bases onto textile fibers for nerve agent hydrolysis. Notably, the composite material showed similar reactivity under ambient conditions compared to the powder material in aqueous alkaline solution. This represents a critical step toward a unified strategy for nerve agent hydrolysis in practical settings, which can significantly reduce the dimensions of filters and increase the efficiency of protective suits.

Scalable and Template-Free Aqueous Synthesis of Zirconium-Based Metal-Organic Framework Coating on Textile Fiber

Organophosphonate-based nerve agents, such as VX, Sarin (GB), and Soman (GD), are among the most toxic chemicals to humankind. Recently, we have shown that Zr-based metal-organic frameworks (Zr-MOFs) can effectively catalyze the hydrolysis of these toxic chemicals for diminishing their toxicity. On the other hand, utilizing these materials in powder form is not practical, and developing scalable and economical processes for integrating these materials onto fibers is crucial for protective gear. Herein, we report a scalable, template-free, and aqueous solution-based synthesis strategy for the production of Zr-MOF-coated textiles. Among all MOF/fiber composites reported to date, the MOF-808/polyester fibers exhibit the highest rates of nerve agent hydrolysis. Moreover, such highly porous fiber composites display significantly higher protection time compared to that of its parent fabric for a mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES). A decreased diffusion rate of toxic chemicals through the MOF layer can provide time needed for the destruction of the harmful species.

Facile and Scalable Coating of Metal-Organic Frameworks on Fibrous Substrates by a Coordination Replication Method at Room Temperature

Coating of metal-organic frameworks (MOFs) on flexible substrates is a crucial technology for applications such as purification/separation, sensing, and catalysis. In this work, a facile coordination replication strategy was developed to coat various MOFs onto flexible fibrous materials where a dense layer of an insoluble precursor template, such as a layered hydroxide salt, was first deposited onto a fiber substrate via a mild interfacial reaction and then rapidly transformed into a MOF coating in a ligand solution at room temperature. Spatiotemporal harmonization of solid precursor dissolution and MOF crystallization enabled precise replication of the precursor layer morphology to form a continuous MOF coating composed of intergrown crystals. The resulting flexible, highly robust, and processable fibrous MOF/textile composites demonstrated tremendous potential for industrially relevant applications such as continuous removal of the organosulfur compound dibenzothiophene from simulated gasoline and ammonia capture. This rapid, versatile, eco-friendly, and scalable MOF coating process at room temperature gives rise to new possibilities for preparing MOF-coated functional materials.

Nature-Inspired Windmill for Water Collection in Complex Windy Environments

Nature-inspired water collection technology has been well-recognized as an effective solution for relieving water shortage hardships, and yet remains challenging when being used in an actual natural environment. In this work, we have successfully developed a promising water-collecting windmill that can be used in complex windy environments, by taking integrative inspiration from the liquid-manipulation strategies adopted by rice leaves, cacti, Nepenthes pitcher plants, and butterflies. The unique directional grooves on the blade surface with ridge-like walls with a shape gradient, combined with a molecular slippery layer, are crucial for not only water deposition but also directional drainage in water collection. Besides, the engineering design of rotatable blades turns the adverse effect of strong winds into a positive one, along with the nature-inspired surface topography and physicochemical property. Such a novel windmill has shown unprecedented water-collecting performance in a static environment, in strong wind, and in intermittent wind. Furthermore, the windmill can sense the wind-blowing direction and adjust its facing direction accordingly to ensure maximum utilization of wind power. It is believed that this work will bring a broad guiding significance to the design of smart water-harvesting materials and devices for application in more complex situations.

Fully Controllable Design and Fabrication of Three-Dimensional Lattice Supercapacitors

Supercapacitors have been proven to be a superior candidate for energy storage systems. Yet, most of them are of an approximately two-dimensional structure, without taking full advantage of the spatial superiority to load more mass of active materials. Moreover, three-dimensional (3D) sponge electrodes may hinder ion transmission due to the significant variations in porous structures. In this work, fully controllable 3D lattice supercapacitors with the ordered porous structures were fabricated for the first time via using 3D printing technology. To increase the mass loading capacity, active materials, including metal films, carbon nanomaterials, and transition-metal sulfides, were hierarchically loaded onto the surface of the lattice substrate by using electroless plating, dip-coating, and electrodeposition methods. The as-fabricated CoNi₂S₄/Ni/octet-truss lattice (OTL) electrode demonstrates a high capacitance until up to 1216 F g^-1 (KOH electrolyte). The lattice asymmetric all-solid-state supercapacitors, composed of CoNi₂S₄/Ni/OTL as anode and carbon materials/Ni/OTL as cathode, display the highest specific capacitance of 23.5 F g^-1, a 10.6 Wh kg^-1 energy density at the 2488.3 W kg^-1 power density, and a robustness (77.3% capacitance retention after 1800 cycles). We expect that the design and fabrication method for the fully controllable 3D lattice supercapacitor with hierarchical activating materials can open a door to develop 3D supercapacitors.

Normalized Total Gradient: A New Measure for Multispectral Image Registration

Image registration is a fundamental issue in multispectral image processing, and is challenged by two main characteristics of multispectral images. First, the regional intensities can be essentially different between band images. Second, the local contrasts of two difference band images are inconsistent or even reversed. Conventional measures can align images with different regional intensity levels, but may fail in the circumstance of severe local intensity variation. In this paper, a new measure called normalized total gradient is proposed for multispectral image registration. The measure is based on the key assumption (observation) that the gradient of the difference between two aligned band images is sparser than that between two misaligned ones. A registration framework, which incorporates image pyramid and global/local optimization, is further introduced for affine transform. Experimental results validate that the proposed method is not only effective for multispectral image registration, but also applicable to general unimodal/multimodal image registration tasks. It performs better than or comparable to the existing methods, both quantitatively and qualitatively.

Effect of graphene oxide inclusion on the optical reflection of a silica photonic crystal film

In this study, the inclusion of graphene oxide in silica photonic crystals was found to affect optical reflectance intensity and reflectance peak broadening. The quantitative relationship between weight percentage and the reflected light intensity and corresponding wavelength shift of light GO-decorated photonic crystals was studied, providing a useful parameter in the rational design of antireflection coatings for GO-based photonic crystal films. Comparison of the experimental results with a pure SiO₂ particle film shows that a SiO₂ particle surface layer incorporated with a fixed graphene oxide weight percentage results in broadening of the peak and a decrease in reflectance intensity. The percentage of the reduction in reflectance intensity is a function of particle size, as indicated by the structured color film surface, demonstrating the possibility of estimating the effect of different graphene oxide inclusion percentages on the antireflection properties of photonic crystal films.

In this study, the inclusion of graphene oxide in silica photonic crystals was found to affect optical reflectance intensity and reflectance peak broadening.

Flexible Slippery Surface to Manipulate Droplet Coalescence and Sliding, and Its Practicability in Wind-Resistant Water Collection

A flexible slippery membrane (FSM) with tunable morphology and high elastic deformability has been developed by infusing perfluoropolyether (PFPE) into a fluorinated-copolymer-modified thermoplastic polyurethane (TPU) nanofiberous membrane. To immobilize PFPE in TPU matrix, we synthesized a fluorinated-copolymer poly(DFMA-co-IBOA-co-LMA) with low surface energy, high chemical affinity to PFPE, adequate flexibility, and strong physical adhesion on TPU. Upon external tensile stress, the as-prepared FSM can realize a real-time manipulation of water sliding and coalescence on it. Furthermore, it exhibits the ability to preserve the captured water from being blown away by strong wind, which ensures the water collection efficiency in windy regions.

Bidirectional texture function image super-resolution using singular value decomposition

The bidirectional texture function (BTF) is widely employed to achieve realistic digital reproduction of real-world material appearance. In practice, a BTF measurement device usually does not use high-resolution (HR) cameras in data collection, considering the high equipment cost and huge data space required. The limited image resolution consequently leads to the loss of texture details in BTF data. This paper proposes a fast BTF image super-resolution (SR) algorithm to deal with this issue. The algorithm uses singular value decomposition (SVD) to separate the collected low-resolution (LR) BTF data into intrinsic textures and eigen-apparent bidirectional reflectance distribution functions (eigen-ABRDFs) and then improves the resolution of the intrinsic textures via image SR. The HR BTFs can be finally obtained by fusing the reconstructed HR intrinsic textures with the LR eigen-ABRDFs. Experimental results show that the proposed algorithm outperforms the state-of-the-art single-image SR algorithms in terms of reconstruction accuracy. In addition, thanks to the employment of SVD, the proposed algorithm is computationally efficient and robust to noise corruption.

Spectral bidirectional texture function reconstruction by fusing multiple-color and spectral images

Spectral bidirectional texture function (BTF) is essential for accurate reproduction of material appearance due to its nature of conveying both spatial and spectral information. A practical issue is that the acquisition of raw spectral BTFs is time-consuming. To resolve the limitation, this paper proposes a novel framework for efficient spectral BTF acquisition and reconstruction. The framework acquires red-green-blue (RGB) BTF images and just one spectral image. The full spectral BTFs are reconstructed by fusing the RGB and spectral images based on nonnegative matrix factorization (NMF). Experimental results indicate that the accuracy of spectral reflectance reconstruction is higher than that of existing algorithms. With the reconstructed spectral BTFs, the material appearance can be reproduced with high fidelity under various illumination conditions.

Constructing safe and durable antibacterial textile surfaces using a robust graft-to strategy via covalent bond formation

Recently zwitterionic materials have been widely applied in the biomedical and bioengineering fields due to their excellent biocompatibility. Inspired by these, this study presents a graft-to strategy via covalent bond formation to fabricate safe and durable antibacterial textile surfaces. A novel zwitterionic sulfobetaine containing triazine reactive group was specifically designed and synthesized. MTT assay showed that it had no obvious cytotoxicity to human skin HaCaT cells as verified by ca. 89.9% relative viability at a rather high concentration of 0.8 mg·mL⁻¹. In the evaluation for its skin sensitization, the maximum score for symptoms of erythema and edema in all tests were 0 in all observation periods. The sulfobetaine had a hydrophilic nature and the hydrophilicity of the textiles was enhanced by 43.9% when it was covalently grafted onto the textiles. Moreover, the textiles grafted with the reactive sulfobetaine exhibited durable antibacterial activities, which was verified by the fact that they showed antibacterial rates of 97.4% against gram-positive S. aureus and 93.2% against gram-negative E. coli even after they were laundered for 30 times. Therefore, the titled zwitterionic sulfobetaine is safe to human for healthcare and wound dressing and shows a promising prospect on antibacterial textile application.

Beads-on-String Structured Nanofibers for Smart and Reversible Oil/Water Separation with Outstanding Antifouling Property

It is challenging to explore a unified solution for the treatment of oily wastewater from complex sources. Thus, membrane materials with flexible separation schemes are highly desired. Herein, we fabricated a smart membrane by electrospinning TiO2 doped polyvinylidene fluoride (PVDF) nanofibers. The as-formed beads-on-string structure and hierarchical roughness of the nanofibers contribute to its superwetting/resisting property to liquids, which is desirable in oil/water separation. Switched simply by UV (or sunlight) irradiation and heating treatment, the smart membrane can realize reversible separation of oil/water mixtures by selectively allowing water or oil to pass through alone. Most importantly, the as-prepared nanofiber membrane possesses outstanding antifouling and self-cleaning performance resulting from the photocatalytic property of TiO2, which has practical significance in saving solvents and recycling materials. This work provides a route for fabricating cost-effective, easily scaled up, and recyclable membranes for on-demand oil/water separation in versatile situations, which can be of great usage in the new green separation technology.

Graphene oxide-enhanced sol-gel transition sensitivity and drug release performance of an amphiphilic copolymer-based nanocomposite

We report the fabrication of a highly sensitive amphiphilic copolymer-based nanocomposite incorporating with graphene oxide (GO), which exhibited a low-intensity UV light-triggered sol-gel transition. Non-cytotoxicity was observed for the composite gels after the GO incorporation. Of particular interest were the microchannels that were formed spontaneously within the GO-incorporated UV-gel, which expedited sustained drug release. Therefore, the present highly UV-sensitive, non-cytotoxic amphiphilic copolymer-based composites is expected to provide enhanced photothermal therapy and chemotherapy by means of GO's unique photothermal properties, as well as through efficient passive targeting resulting from the sol-gel transition characteristic of the copolymer-based system with improved sensitivity, which thus promises the enhanced treatment of patients with cancer and other diseases.

Fast Multispectral Imaging by Spatial Pixel-Binning and Spectral Unmixing

Multispectral imaging system is of wide application in relevant fields for its capability in acquiring spectral information of scenes. Its limitation is that, due to the large number of spectral channels, the imaging process can be quite time-consuming when capturing high-resolution (HR) multispectral images. To resolve this limitation, this paper proposes a fast multispectral imaging framework based on the image sensor pixel-binning and spectral unmixing techniques. The framework comprises a fast imaging stage and a computational reconstruction stage. In the imaging stage, only a few spectral images are acquired in HR, while most spectral images are acquired in low resolution (LR). The LR images are captured by applying pixel binning on the image sensor, such that the exposure time can be greatly reduced. In the reconstruction stage, an optimal number of basis spectra are computed and the signal-dependent noise statistics are estimated. Then the unknown HR images are efficiently reconstructed by solving a closed-form cost function that models the spatial and spectral degradations. The effectiveness of the proposed framework is evaluated using real-scene multispectral images. Experimental results validate that, in general, the method outperforms the state of the arts in terms of reconstruction accuracy, with additional 20× or more improvement in computational efficiency.

Antibacterial modification of an injectable, biodegradable, non-cytotoxic block copolymer-based physical gel with body temperature-stimulated sol-gel transition and controlled drug release

Biomaterials are being extensively used in various biomedical fields; however, they are readily infected with microorganisms, thus posing a serious threat to the public health care. We herein presented a facile route to the antibacterial modification of an important A-B-A type biomaterial using poly (ethylene glycol) methyl ether (mPEG)- poly(ε-caprolactone) (PCL)-mPEG as a typical model. Inexpensive, commercial bis(2-hydroxyethyl) methylammonium chloride (DMA) was adopted as an antibacterial unit. The effective synthesis of the antibacterial copolymer mPEG-PCL-∼∼∼-PCL-mPEG (where ∼∼∼ denotes the segment with DMA units) was well confirmed by FTIR and (1)H NMR spectra. At an appropriate modification extent, the DMA unit could render the copolymer mPEG-PCL-∼∼∼-PCL-mPEG highly antibacterial, but did not largely alter its fascinating intrinsic properties including the thermosensitivity (e.g., the body temperature-induced sol-gel transition), non-cytotoxicity, and controlled drug release. A detailed study on the sol-gel-sol transition behavior of different copolymers showed that an appropriate extent of modification with DMA retained a sol-gel-sol transition, despite the fact that a too high extent caused a loss of sol-gel-sol transition. The hydrophilic and hydrophobic balance between mPEG and PCL was most likely broken upon a high extent of quaternization due to a large disturbance effect of DMA units at a large quantity (as evidenced by the heavily depressed PCL segment crystallinity), and thus the micelle aggregation mechanism for the gel formation could not work anymore, along with the loss of the thermosensitivity. The work presented here is highly expected to be generalized for synthesis of various block copolymers with immunity to microorganisms. Light may also be shed on understanding the phase transition behavior of various multiblock copolymers.

Durable Antibacterial and Nonfouling Cotton Textiles with Enhanced Comfort via Zwitterionic Sulfopropylbetaine Coating

A rapid, environment-friendly, and cost-effective finishing method has been developed for cotton textiles by using zwitterionic NCO-sulfopropylbetaine as the antibacterial finishing agent through covalent bond. The sulfopropylbetaine-finished cotton textile exhibits durable broad-spectrum antibacterial and nonfouling activity, improved mechanical properties, and enhanced comfort.

Biomimetic Water-Collecting Fabric with Light-Induced Superhydrophilic Bumps

To develop an efficient water-collecting surface that integrates both fast water-capturing and easy drainage properties is of high current interest for addressing global water issues. In this work, a superhydrophobic surface was fabricated on cotton fabric via manipulation of both the surface roughness and surface energy. This was followed by a subsequent spray coating of TiO2 nanosol that created light-induced superhydrophilic bumps with a unique raised structure as a result of the interfacial tension of the TiO2 nanosol sprayed on the superhydrophobic fiber surface. These raised TiO2 bumps induce both a wettability gradient and a shape gradient, synergistically accelerating water coalescence and water collection. The in-depth study revealed that the quantity and the distribution of the TiO2 had a significant impact on the final water collection efficiency. This inexpensive and facilely fabricated fabric biomimicks the desert beetle's back and spider silk, which are capable of fog harvesting without additional energy consumption.

A novel graphene oxide-based fluorescent nanosensor for selective detection of Fe(3+) with a wide linear concentration and its application in logic gate

A graphene oxide-based fluorescent nanosensor AGO has been designed and synthesized by covalent grafting allylamine onto GO surface. In aqueous media, AGO displays a highly selective and sensitive discrimination of Fe(3+) from Fe(2+) and other metal ions through electron transfer-induced fluorescence quenching. The quenching of AGO fluorescence is linearly proportional to Fe(3+) concentration in a wide range of 0-120 μM (correlation coefficient R(2)=0.9994). Moreover, AGO can be used to construct a combinational three-input logic gate to discriminate Fe(3+) and Fe(2+). The logic gate works well in intracellular fluorescence imaging, which shows a potential as a promising platform for biosensing analysis.