Single‐cell nanoencapsulation, forming cell‐in‐shell structures, provides chemical tools for endowing living cells, in a programmed fashion, with exogenous properties that are neither innate nor ...naturally achievable, such as cascade organic‐catalysis, UV filtration, immunogenic shielding, and enhanced tolerance in vitro against lethal factors in real‐life settings. Recent advances in the field make it possible to further fine‐tune the physicochemical properties of the artificial shells encasing individual living cells, including on‐demand degradability and reconfigurability. Many different materials, other than polyelectrolytes, have been utilized as a cell‐coating material with proper choice of synthetic strategies to broaden the potential applications of cell‐in‐shell structures to whole‐cell catalysis and sensors, cell therapy, tissue engineering, probiotics packaging, and others. In addition to the conventional “one‐time‐only” chemical formation of cytoprotective, durable shells, an approach of autonomous, dynamic shellation has also recently been attempted to mimic the naturally occurring sporulation process and to make the artificial shell actively responsive and dynamic. Here, the recent development of synthetic strategies for formation of cell‐in‐shell structures along with the advanced shell properties acquired is reviewed. Demonstrated applications, such as whole‐cell biocatalysis and cell therapy, are discussed, followed by perspectives on the field of single‐cell nanoencapsulation.
Single‐cell nanoencapsulation offers a chemical tool for enhancing cell viability in vitro against harmful stresses, promising potential in many applications including biocatalysis and cell therapy. Recent advances in synthetic strategies for forming cell‐in‐shell structures with unprecedented shell properties are discussed along with demonstrated applications.
Nanoscale surface‐engineering plays an important role in improving the performance of battery electrodes. Nb2O5 is one typical model anode material with promising high‐rate lithium storage. However, ...its modest reaction kinetics and low electrical conductivity obstruct the efficient storage of larger ions of sodium or potassium. In this work, partially surface‐amorphized and defect‐rich black niobium oxide@graphene (black Nb2O5−x@rGO) nanosheets are designed to overcome the above Na/K storage problems. The black Nb2O5−x@rGO nanosheets electrodes deliver a high‐rate Na and K storage capacity (123 and 73 mAh g−1, respectively at 3 A g−1) with long‐term cycling stability. Besides, both Na‐ion and K‐ion full batteries based on black Nb2O5−x@rGO nanosheets anodes and vanadate‐based cathodes (Na0.33V2O5 and K0.5V2O5 for Na‐ion and K‐ion full batteries, respectively) demonstrate promising rate and cycling performance. Notably, the K‐ion full battery delivers higher energy and power densities (172 Wh Kg−1 and 430 W Kg−1), comparable to those reported in state‐of‐the‐art K‐ion full batteries, accompanying with a capacity retention of ≈81.3% over 270 cycles. This result on Na‐/K‐ion batteries may pave the way to next‐generation post‐lithium batteries.
Surface‐amorphized and defect‐rich black niobium oxide@graphene nanosheets are constructed as anode materials for sodium and potassium storage, delivering a high‐rate Na/K storage capacity (123 and 73 mAh g−1, respectively at 3 A g−1) and long‐term cycling stability. Na/K full batteries based on the prepared anodes also demonstrate high energy and power densities.
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•Strategies for pore surface engineering of MOFs are summarized.•Effects of pore surface functionalization of MOFs on catalysis are discussed.•Challenges and opportunities of pore ...surface engineering of MOFs for catalysis are presented.
Metal–organic frameworks (MOFs), a class of emerging crystalline porous materials, have received great attention for their prospective applications in various areas. In terms of catalytic application, MOFs combine both the merits of heterogeneous and homogeneous catalysis, such as recyclability, high efficiency and selectivity, well-define active sites, etc., in which the pore structures and environment of MOFs play critical roles. To further expand the applications of MOFs for catalysis, the appropriate pore surface engineering of MOFs is imperative to create more active sites, modulate the catalytic behaviors, and thus enhance the catalytic properties. In this review, recent progress achieved in heterogeneous catalysis with pore-surface-engineered MOFs has been summarized. Different strategies for pore surface engineering of MOFs are discussed systematically, with a focus on the creation or introduction of active sites for catalysis.
Three-dimensional (3D) printing by material extrusion is being widely explored to prepare patient-specific scaffolds from biodegradable polyesters such as poly(lactic acid) (PLA). Although they ...provide the desired mechanical support, PLA scaffolds lack bioactivity to promote bone regeneration. The aim of this work was to develop a surface engineering approach for enhancing the osteogenic activity of 3D printed PLA scaffolds. Macro-porous PLA scaffolds were prepared by material extrusion with 70.2% porosity. Polyethyleneimine was chemically conjugated to the alkali-treated PLA scaffolds followed by conjugation of citric acid. These polymer-grafted scaffolds were immersed in the simulated body fluid to yield scaffolds coated with calcium-deficient hydroxyapatite (PLA-HaP). Surface roughness and water wettability were enhanced after surface modification. PLA-HaP scaffolds exhibited a steady release of calcium ions in an aqueous medium for 10 days. The adhesion and proliferation of human mesenchymal stem cells (hMSCs) on PLA-HaP was ~50% higher than on PLA. Mineral deposition resulting from hMSC osteogenesis on PLA-HaP scaffolds was nearly twice that on PLA scaffolds. This was corroborated by the increase in alkaline phosphatase activity and expression of several osteogenic genes. Thus, this work presents a surface modification strategy to enhance the bioactivity of 3D printed scaffolds for bone tissue regeneration.
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•3D printed scaffolds of poly(lactic acid) with 70% porosity were prepared by materials extrusion.•Scaffold surface was modified by grafting polyethyleneimine and citric acid followed by deposition of calcium phosphate.•Scaffolds released calcium ions and exhibited enhanced roughness and water wettability after surface modification.•Adhesion and proliferation of mesenchymal stem cells increased by 50% after surface modification.•Enhanced stem cell osteogenesis on the surface modified scaffolds resulted in doubling of the mineralization.
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Various oils discharged from daily life and industrial production, as well as frequent oil spillages, have led to severe water pollution and ecological problems. Mussel-inspired ...polydopamine has been widely applied for fabrication of superhydrophobic materials for oil/water separation. However, the need of additional nanoparticles via tedious steps to construct nanostructures, and the high cost of dopamine itself limit its practical applications. Moreover, the application modes of superhydrophobic materials for oil/water separation are monotonous, which will limit the applied range of the superhydrophobic materials. For example, superhydrophobic sponge was usually used for adsorbing oil droplets or oil spills from water, while superhydrophobic fabric or mesh was usually used for separating bulk layered oil/water mixture. Therefore, developing simple and low-cost mussel-inspired surface modification strategy toward superhydrophobic materials, as well as diverse application modes for oil/water separation, is still highly desired. In this study, superhydrophobic sponge and fabric with nanostructures, which exhibits excellent performance for diverse oil/water separation, have been fabricated through a novel one-step and cost-effective mussel-inspired approach. The resultant superhydrophobic sponge exhibits outstanding oil absorption capability (weight gains up to 8860%), while the superhydrophobic fabric can effectively separate oil/water mixture. Moreover, diverse modes for oil/water separation have been developed for the first time. For example, water-in-oil emulsion can be highly-efficient separated by a compressed superhydrophobic sponge (~1800L m-2h−1 bar−1 for water-in-oil emulsion, and above 99% rejection rate for water droplets), while crude oil spills can be efficiently collected by a superhydrophobic boat (above 98%).
Surface adsorption behavior and electron transfer determine the catalytic activity in hydrogen evolution reaction (HER). However, the inevitable surface oxidation of NbC hinders electron transfer and ...hydrogen conversion. The surface adsorption behavior and electron transfer of NbC are optimized by doping Cu+ as well as modifying the orbital hybridizations. Benefiting from the introduced electron interaction of Cu+, the lower p-d hybridization between Nb and O reduces the Nb-O bond and affords the Cu-NbC thinner surface oxidation layer. The reduced surface oxidation degree favors electron transfer. Further, the electron orbital hybridization modulates the electron states and optimizes the hydrogen adsorption behavior of Cu-NbC for efficient hydrogen conversion. As the electrochemical results, the obtained Cu-NbC demands 271 mV to drive 10 mA cm−2, which is 50 times higher than that of NbC (only 0.2 mA cm−2 at the same overpotential). Hence, we believe the orbital hybridization manipulation strategy renders a valuable solution for designing efficient HER catalysts.
A orbital hybridization engineering for boosting the HER kinetics by doping Cu+ in NbC is first proposed. The orbital hybridization engineering optimizes the electron structure of Cu-NbC, reducing the surface oxidation layer and optimizing the hydrogen adsorption strength. Then thus, the boosting electron transfer and intermediates conversion promote the HER kinetic. This work paves a new way for rationally designing efficient catalysts for alkaline HER. Display omitted
•Cu+ is doped into NbC by a one-pot molten salt method.•Introduced electron interaction of Cu+ modify p-d hybridization between Nb and O.•The reducing surface oxidation degree favors the electron transfer.•Orbital hybridization engineering optimizes the electron state at Fermi Level.•Efficient electron transfer and optimized adsorption behavior boost the reaction kinetics.
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•Design of a biofunctionalization approach for the fabrication of 3D-printed immunosensors.•Development of the 3D-printed COVID-19 immunosensor with electronic readout.•Determination ...of the COVID-19 recombinant protein via competitive immunoassay.•Feasibility of 3D-printed electronic devices to aid with the COVID-19 pandemic.
3D printing technology has brought light in the fight against the COVID-19 global pandemic event through the decentralized and on-demand manufacture of different personal protective equipment and medical devices. Nonetheless, since this technology is still in an early stage, the use of 3D-printed electronic devices for antigen test developments is almost an unexplored field. Herein, a robust and general bottom-up biofunctionalization approach via surface engineering is reported aiming at providing the bases for the fabrication of the first 3D-printed COVID-19 immunosensor prototype with electronic readout. The 3D-printed COVID-19 immunosensor was constructed by covalently anchoring the COVID-19 recombinant protein on a 3D-printed graphene-based nanocomposite electrode surface. The electrical readout relies on impedimetrically monitoring changes at the electrode/electrolyte interface after interacting with the monoclonal COVID-19 antibody via competitive assay, fact that hinders the redox conversion of a benchmark redox marker. Overall, the developed 3D-printed system exhibits promising electroanalytical capabilities in both buffered and human serum samples, displaying an excellent linear response with a detection limit at trace levels (0.5 ± 0.1 μg·mL−1). Such achievements demonstrate advantage of light-of-speed distribution of 3D printing datafiles with localized point-of-care low-cost printing and bioelectronic devices to help contain the spread of emerging infectious diseases such as COVID-19. This technology is applicable to any post-COVID-19 SARS diseases.
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•A −Cl/O-terminated MXene was prepared by environmentally friendly molten-salt method with broad and strength electromagnetic wave absorption (3.44 GHz and 45.72 dB).•−Cl/O-terminals ...effectively limit the high conductivity and optimize the polarization effect.•The polarization strength has been creatively studied in terms of the electron population.
The emerging two-dimensional material, Ti3C2Tx MXene, has attracted significant attention in the realm of electromagnetic wave absorption owing to its exceptional inherent conductivity and distinctive microstructure. However, similar to other conductive materials, MXene encounters the challenge of impedance mismatch, thereby impeding the electromagnetic wave absorption capability in single-component MXene materials. In this study, a molten chlorine-salt method was employed to gain MXene samples with varying surface-chlorine/oxygen (Cl/O) ratios by surface engineering. Notably, among these samples, Cl/Ni-MX-6 exhibited an impressive minimum reflection loss value of −45.72 dB (1.6 mm) and an effective absorption bandwidth of 3.44 GHz (1.3 mm). This study revealed that increasing the etchant content enhances the delamination effect of MXene and leads to adjust Cl/O ratio. Importantly, the modulation of −Cl/O surface functional groups can limit the electronic conductivity, while the number and species of different kinds of surface dipoles will control the polarization effect, ultimately optimizing the electromagnetic wave absorption performance of pure MXene. These insights contribute to ongoing efforts aimed at enhancing the performance of MXene-based materials in the field of electromagnetic wave absorption as well as get a better understanding of the electromagnetic loss mechanism.
Laser-textured surfaces enabling reversible wettability switching and improved optical properties are gaining importance in cutting-edge applications, including self-cleaning interfaces, tunable ...optical lenses, microfluidics, and lab-on-chip systems. Fabrication of such surfaces by combining nanosecond-laser texturing and low-temperature annealing of titanium Ti-6Al-4V alloy was demonstrated by Lian et al. in ACS Appl. Mater. Inter. 2020, 12 (5), 6573–6580. However, it is difficult to agree with (i) their contradictory explanation of the wettability transition due to low-temperature annealing and (ii) their theoretical description of the optical behavior of the laser-textured titanium surface. This comment provides an alternative viewsupported by both experimental results and theoretical investigationon how the results by Lian et al. could be interpreted more correctly. The annealing experiments clarify that controlled contamination is crucial in obtaining consistent surface wettability alterations after low-temperature annealing. Annealing of laser-textured titanium at 100 °C in contaminated and contaminant-free furnaces leads to completely different wettability transitions. Analysis of the surface chemistry by XPS and ToF-SIMS reveals that (usually overlooked) contamination with hydrophobic polydimethylsiloxane (PDMS) may arise from the silicone components of the furnace. In this case, a homogeneous thin PDMS film over the entire surface results in water repellency (contact angle of 161° and roll-off angle of 15°). In contrast, annealing under the same conditions but in a contaminant-free furnace preserves the initial superhydrophilicity, whereas the annealing at 350 °C turns the hydrophobicity “off”. The theoretical calculations of optical properties demonstrate that the laser-induced oxide layer formed during the laser texturing significantly influences the surface optical behavior. Consequently, the interference of light reflected by the air–oxide and the oxide–metal interfaces should not be neglected and enables several advanced approaches to exploit such optical properties.
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•Ultrathin sulfated NiFe-LDH nanosheets were synthesized.•High-valence Ni and Fe sites were present on the surface of sulfated NiFe-LDH nanosheets.•High-valence Fe promoted an O-O ...coupling on Ni sites at low overpotential.•Sulfated NiFe-LDH nanosheets exhibited excellent OER activity and high stability.
High-valence Ni and Fe metal sites have demonstrated a crucial role in enhancing the catalytic performances of NiFe-LDH electrocatalysts in oxygen evolution reaction (OER). Although considerable OER catalytic performances achieved under high overpotential, the catalytic talent of NiFe-LDH electrocatalysts at low overpotential is rarely realized due to the absence of high-valence Ni and Fe sites. We herein report a surface engineering route to fabricate sulfated NiFe-LDH nanosheets via ion exchange strategy in sulfate-rich media. XPS results reveal a modified surface electronic structure with high-valence Ni and Fe after ion exchange reaction. Computational PDOS results suggest that computed d-band centers (εd) of Fe and Ni for sulfated NiFe-LDH show a significant downward shift resulting an increased valence of metal cation with orbital volume shrinkage. The high-valence Fe can facilitate a optimized multi-electron process of Ni center from NiII-OH−/NiIII-OH− to NiIV-OOH rather than NiII/NiIII to NiIV at low overpotential. The high-valence Ni can serve as the highly active center for O-O coupling during OER process. Combined with the synergetic action of high-valence Fe and Ni, the sulfated NiFe-LDH nanosheets exhibit much larger reaction kinetics and outstanding electrocatalytic activity on glassy carbon electrode (η10 = 219 mV, η50 = 288 mV) with a remarkable long-term stability.
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