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Affinity-based electrochemical (AEC) biosensors have gained more attention in the field of point-of-care management. However, AEC sensing is hampered by biofouling of the electrode surface and degradation of the antifouling material. Therefore, a breakthrough in antifouling nanomaterials is crucial for the fabrication of reliable AEC biosensors. Herein, for the first time, we propose 1-pyrenebutyric acid-functionalized MXene to develop an antifouling nanocomposite to resist biofouling in the immunosensors. The nanocomposite consisted of a 3D porous network of bovine serum albumin cross-linked with glutaraldehyde with functionalized MXene as conductive nanofillers, where the inherited oxidation resistance property of functionalized MXene improved the electrochemical lifetime of the nanocomposite. On the other hand, the size-extruded porous structure of the nanocomposite inhibited the biofouling activity on the electrode surface for up to 90 days in real samples. As a proof of concept, the antifouling nanocomposite was utilized to fabricate a multiplexed immunosensor for the detection of C-reactive protein (CRP) and ferritin biomarkers. The fabricated sensor showed good selectivity over time and an excellent limit of detection for CRP and ferritin of 6.2 and 4.2 pg/mL, respectively. This research successfully demonstrated that functionalized MXene-based antifouling nanocomposites have great potential to develop high-performance and low-cost immunosensors.

In order to control the initial rate of enzymatic degradation, a biodegradable poly(l-lactide) (PLLA) was modified by the incorporation of a small amount of poly(dimethyl siloxane) (PDMS) or fluorocarbons, both of which are hydrophobic and thus inactive to enzymatic degradation. Surface analyses via contact angle and X-ray photoelectron spectroscopy (XPS) revealed the dominance of PDMS and fluorocarbons on the surface layer of the modified PLLA films, possessing lower surface energies than PLLA. Enzymatic degradation employing proteinase K showcased a notable slowdown in the initial degradation of the modified PLLA films, likely due to enhanced hydrophobicity and reduced enzyme susceptibility of the modified surface layers.

[Display omitted] • 3D macroporous biocomposites were fabricated using an electrohydrodynamic process. • The biocomposites were composed of a fibrous matrix structure of PCL/CDHA/collagen. • Biocomposites with the microfibrous topographical cue significantly improved in vitro cellular responses. • The fibrous biocomposite encouraged new bone formation in vivo. The fabrication of biomedical composite materials with macroporous structures and unique topographical cues has been widely investigated to achieve successful bone regeneration. In this study, porous biocomposites consisting of microfibrous bundles fabricated using an electrohydrodynamic direct printing process were prepared. The fibrous composite structure was composed of a fibrous matrix structure of polycaprolactone/α-tricalcium phosphate and collagen coated in fibrous biocomposites. Various cellular activities, cell proliferation, and osteogenic differentiation in biocomposites have been investigated using preosteoblasts (MC3T3-E1). The in vitro results demonstrated that biocomposites with the microfibrous topographical cue significantly improved various cellular responses, including cell proliferation and mRNA expression levels of osteoblastic genes of MC3T3-E1 cells, compared to biocomposites without a fibrous topography surface that were fabricated through normal 3D printing. This phenomenon could be attributed to the fibrous structure of composites that stimulated cultured cells, thereby activating extracellular signal-related kinases and p38 signaling pathways. To observe the ability of biocomposites for bone regeneration, a rat calvarial defect model was used; the fibrous biocomposite showed significantly higher level of new bone formation in comparison with the 3D-printed control, a biocomposite without fibrous topographical cues. [ABSTRACT FROM AUTHOR]

Various approaches have been made to successfully regenerate tissues or organs. One approach is to design a bioengineered scaffold which simulate the native environment of tissues and organs. This study examined the efficacy of a PCL based fibrous scaffold embedded with decellularized bone extracellular matrix (bdECM) fabricated using electrospinning process. Electrospun fibers are known to mimic the structure of the natural ECM, while bdECM can provide a rich environment for the human mesenchymal stem cells to adhere and differentiate. We found that the bdECM particles strongly influenced the surface characteristics of the fabricated scaffolds such as wettability, water uptake ability, and surface roughness. Also, the cell adhesion depending on the bdECM content was studied in depth. As a result, increased bdECM content in the scaffold showed enhanced cell adhesion and proliferation. Moreover, the ALP activity, calcium deposition, and gene expression results indicate that the bdECM particles had significant effect on osteogenic differentiation. In the present study, the feasibility of the bdECM/PCL scaffold was demonstrated which can be used as a potential biomedical device for hard tissue regeneration. [ABSTRACT FROM AUTHOR]

This illustration is representative of the physical and biological characteristics of the composite scaffold. The composite scaffold, which has been fabricated through three processes, exhibits excellent improved physical properties as well as outstanding osteogenic differentiation. Silanated silica reinforced composite scaffold showed good performance including tensile modulus, water absorption ability, cell initial attachment, proliferation and osteogenic differentiation and have the potential to become implantable materials in hard bone tissue regeneration. • Composite scaffolds composed of PCL and silanated silica particles were suggested for bone tissue regeneration. • The compsite scaffolds were fabricated by optimizing processing conditions including simple melt-blending method and melt-3D printing process. • The composite scaffolds showed remarkable physical properties and produced significant osteogenic differentiation results. Here, we fabricated composite scaffolds consisting of poly ε-caprolactone (PCL) and silanated silica particles and evaluated the performance of these composite scaffolds as suitable alternatives for bone tissue regeneration including their physical properties (tensile modulus, wettability, and surface roughness) and biological properties (cell proliferation, osteogenic differentiation, Q-PCR, western blotting, and migration assay), by culturing human mesenchymal stem cells. PCL/silanated silica scaffolds had outstanding physical characteristics and biological properties including cell proliferation, osteogenic differentiation, and osteoinduction. This silanated-silica composite has a strong potential as a biomaterial and can be applied to bone tissue applications. [ABSTRACT FROM AUTHOR]

The design of bimetallic Co–Fe oxide structures has attracted considerable research attention in magnetic, electrochemical and catalyst materials. This paper reports the production of unique multi crystal-phase Co/Fe/CoFe 2 O 4 by the water–gas shift reaction. The metallic Co and Fe lower the interfacial resistance, resulting in facial charge/ion transport and a dramatic enhancement in the specific capacitance. The multi-phase Co–Fe oxide structures are also found to be applicable to the water–gas shift reaction and CO oxidation. The unique water–gas shift reaction-induced method can be very useful to the design of highly efficient new multi crystal-phase nanostructures. [ABSTRACT FROM AUTHOR]

Photocatalytic CO2reduction is a potential technique for converting solar energy and greenhouse gases into value-added-chemicals. However, limited light absorption and poor charge separation of electron-hole pairs are the main obstacles. Here, we have developed a highly stable, phase-controlled heterostructured photocatalyst of molybdenum sulfide with reduced titania (1T/2H-MoS2@RT) for CO2reduction into CO. The optimized 1T/2H-MoS2@RT produced 1.02 μmol g−1h−1(1480.1 ppm g−1h−1) of CO. The catalyst showed ∼5 and ∼19 times higher activity than RT and MoS2, respectively, and excellent stability over 48 h (8 cycles). Our investigation revealed that the combination of phase-controlled MoS2with RT synergizes the selective conversion of CO2to CO. MoS2acts as a visible light sensitizer and electron transport bridge; however, RT extracts electrons from MoS2because of its lower energy potential. Improved light absorption, CO2adsorption, and rapid electron-hole separation are responsible for the increased catalytic activity and stability.

Anatase-type titanium dioxide (TiO2) anodes were prepared by a polyol-assisted pyro-synthetic process followed by mild annealing at temperatures in the range of 300 to 600degC for 3 h. The XRD studies clearly revealed the formation of anatase-type TiO2 for all of the prepared samples. The average crystallite size, calculated using the Scherrer formula, was determined to be less than 50 nm in all samples. Electron microscopy studies revealed that the particle-size in all samples ranged from 5 to 50 nm. N2 adsorption studies confirmed that the samples show mesoporous characteristics and in particular the TiO2 anode prepared at 500degC demonstrated a unique tri-porous feature that appears to benefit its electrochemical performances vs. lithium. Although there is no order of variation in the particle-size of the samples prepared at temperatures under 600degC, the tri-porous feature in combination with the sufficiently high particle crystallinity in the TiO2 anode prepared at 500degC appears to contribute to its impressive electrochemical lithium storage properties among the prepared electrodes. The pyro-synthetic strategy aids in developing nanostructured battery electrodes with porous morphologies and appears to offer promise for being developed as an energy saving process for large-scale applications.

Among many biomaterials, gelatin methacrylate (GelMA), a photocurable protein, has been widely used in 3D bioprinting process owing to its excellent cellular responses, biocompatibility and biodegradability. However, GelMA still shows a low processability due to the severe temperature dependence of viscosity. To overcome this obstacle, we propose a two-stage temperature control system to effectively control the viscosity of GelMA. To optimize the process conditions, we evaluated the temperature of the cooling system (jacket and stage). Using the established system, three GelMA scaffolds were fabricated in which different concentrations (0, 3 and 10 wt%) of silanated silica particles were embedded. To evaluate the performances of the prepared scaffolds suitable for hard tissue regeneration, we analyzed the physical (viscoelasticity, surface roughness, compressive modulus and wettability) and biological (human mesenchymal stem cells growth, western blotting and osteogenic differentiation) properties. Consequently, the composite scaffold with greater silica contents (10 wt%) showed enhanced physical and biological performances including mechanical strength, cell initial attachment, cell proliferation and osteogenic differentiation compared with those of the controls. Our results indicate that the GelMA/silanated silica composite scaffold can be potentially used for hard tissue regeneration.

The skeletal muscle tissue comprises a hierarchical fibrous structure with fully aligned myofibers. To obtain a unique aligned engineering construct for regenerating muscle tissue, we adopted a submerged bioprinting process. Here, 3 wt % collagen and 6 wt % alginate solutions were used as a matrix cell-encapsulating bioink and supporting solution in the printing bath, respectively. By manipulating the processing parameters (various alginate weight fractions in the bath, nozzle moving speed, and hydrostatic pressure), cell-laden filaments (∼50 μm in diameter) were successfully fabricated. They presented a high degree of alignment of the fibrillated collagen and meaningful initial viability (∼90%) of the C2C12 myoblasts. In vitro cellular responses indicated that fully aligned F-actin filaments of myoblasts were developed, resulting in a high degree of alignment/formation of myotubes, compared to that in the controls (>100 μm diameter of cell-laden filaments). Furthermore, the expression levels of various myogenic genes (Myod1, Myh2, and Myog) were measured using a reverse transcription polymerase chain reaction on day 21 of the cell culture, and the results showed that the cell-laden filaments with a small diameter had considerably greater gene expression levels (2.2–8-fold) than those with a relatively large diameter. Thus, the printing process described herein can provide a new potential biofabricating platform to obtain cell-laden engineering constructs for various tissues.

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Anatase-type titanium dioxide (TiO2) anodes were prepared by a polyol-assisted pyro-synthetic process followed by mild annealing at temperatures in the range of 300 to 600°C for 3 h. The XRD studies clearly revealed the formation of anatase-type TiO2for all of the prepared samples. The average crystallite size, calculated using the Scherrer formula, was determined to be less than 50 nm in all samples. Electron microscopy studies revealed that the particle-size in all samples ranged from 5 to 50 nm. N2adsorption studies confirmed that the samples show mesoporous characteristics and in particular the TiO2anode prepared at 500°C demonstrated a unique tri-porous feature that appears to benefit its electrochemical performances vs. lithium. Although there is no order of variation in the particle-size of the samples prepared at temperatures under 600°C, the tri-porous feature in combination with the sufficiently high particle crystallinity in the TiO2anode prepared at 500°C appears to contribute to its impressive electrochemical lithium storage properties among the prepared electrodes. The pyro-synthetic strategy aids in developing nanostructured battery electrodes with porous morphologies and appears to offer promise for being developed as an energy saving process for large-scale applications.