Zwitterionic peptide-functionalized highly dispersed carbon nanotubes for efficient wastewater treatment

Multi-walled carbon nanotubes (MWCNTs) have displayed great potential as catalyst carriers due to their nanoscale structure and large specific surface area. However, their hydrophobicity and poor dispersibility in water restrict...

A Nanoscale Structure Based on an MIM Waveguide Coupled with a Q Resonator for Monitoring Trace Element Concentration in the Human Body

In this study, a nano-refractive index sensor is designed that consists of a metal–insulator–metal (MIM) waveguide with a stub-1 and an orthogon ring resonator (ORR) with a stub-2. The finite element method (FEM) was used to analyze the transmission characteristics of the system. We studied the cause and internal mechanism of Fano resonance, and optimized the transmission characteristics by changing various parameters of the structure. In our experimental data, the suitable sensitivity could reach 2260 nm/RIU with a figure of merit of 211.42. Furthermore, we studied the detection of the concentration of trace elements (such as Na+) of the structure in the human body, and its sensitivity reached 0.505 nm/mgdL−1. The structure may have other potential applications in sensors.

Water-accessibility of interfibrillar spaces in spruce wood cell walls

Water interactions and accessibility of the nanoscale components of plant cell walls influence their properties and processability in relation to many applications. We investigated the water-accessibility of nanoscale pores within the fibrillar structures of unmodified Norway spruce cell walls by small-angle neutron scattering (SANS) and Fourier-transform infra-red (FTIR) spectroscopy. The different sensitivity of SANS to hydrogenated ($$\hbox {H}_2\hbox {O}$$ H 2 O ) and deuterated water ($$\hbox {D}_2\hbox {O}$$ D 2 O ) was utilized to follow the exchange kinetics of water among cellulose microfibrils. FTIR spectroscopy was used to study the time-dependent re-exchange of OD groups to OH in wood samples transferred from liquid $$\hbox {D}_2\hbox {O}$$ D 2 O to $$\hbox {H}_2\hbox {O}$$ H 2 O . In addition, the effects of drying on the nanoscale structure and its water-accessibility were addressed by comparing SANS results and the kinetics of water exchange between never-dried and dried/rewetted wood samples. The results of the kinetic analyses allowed to identify two processes with different timescales. The diffusion-driven exchange of water in the spaces between microfibrils, which was observed with both SANS and FTIR, takes place within minutes and rather homogeneously. The second, slower process appeared only in the OD/OH re-exchange followed by FTIR, and it still continued after several weeks of immersion in $$\hbox {H}_2\hbox {O}$$ H 2 O . SANS could not detect any significant difference between the never-dried and dried/rewetted samples, whereas FTIR revealed a small portion of OD groups that resisted the re-exchange and this portion became larger with drying. Graphic abstract

The Development of Polydimethysiloxane/ZnO–GO Antifouling Coatings

The development of antifouling coating for sensor is desirable because the biofilm can shorten sensor’s life and cause inaccurate reading. In this study, a facile one-pot reaction was used to synthesized ZnO–graphene oxide (GO) (ZnO–GO) nanocomposites. Different amount of ZnO–GO was incorporated in the polydimethylsiloxane (PDMS) matrix respectively though a simple solution mixing method, in order to create PDMS/ZnO–GO nanocomposite (PZGO). The coating was obtained directly by spin coating of PZGO/tetrahydrofuran suspension. The hydrophobicity, surface roughness (Ra), surface free-energy (SFE) and nanoscale structure were investigated as antifouling factors. Antifouling tests were performed using two marine microorganisms, the cyanobacterium Synechococcus sp. Strain PCC 7002 and the diatom Phaeodactylum tricornutum. PZGO0.2 (mass ratio of ZnO–GO to PDMS: 0.2 wt%) displayed excellent antifouling property with 8.5% of Synechococcus sp. Strain PCC 7002 biofilm coverage, while PZGO0.1 (mass ratio of ZnO–GO to PDMS: 0.1 wt%) showed 2.4% P. tricornutum biofilm coverage. The antifouling property of the synthesized PZGO nanocomposite can be attributed to its high Ra and hydrophobicity which was caused by the good dispersion of ZnO–GO in PDMS matrix. This study suggests a potential of PZGO nanocomposite for sensor’s antifouling coating, which could contribute to improve sensor’s durability relating to biofouling in future. Graphic Abstract

Intercalated disk nanoscale structure regulates cardiac conduction

The intercalated disk (ID) is a specialized subcellular region that provides electrical and mechanical connections between myocytes in the heart. The ID has a clearly defined passive role in cardiac tissue, transmitting mechanical forces and electrical currents between cells. Recent studies have shown that Na+ channels, the primary current responsible for cardiac excitation, are preferentially localized at the ID, particularly within nanodomains such as the gap junction–adjacent perinexus and mechanical junction–associated adhesion-excitability nodes, and that perturbations of ID structure alter cardiac conduction. This suggests that the ID may play an important, active role in regulating conduction. However, the structures of the ID and intercellular cleft are not well characterized and, to date, no models have incorporated the influence of ID structure on conduction in cardiac tissue. In this study, we developed an approach to generate realistic finite element model (FEM) meshes replicating nanoscale of the ID structure, based on experimental measurements from transmission electron microscopy images. We then integrated measurements of the intercellular cleft electrical conductivity, derived from the FEM meshes, into a novel cardiac tissue model formulation. FEM-based calculations predict that the distribution of cleft conductances is sensitive to regional changes in ID structure, specifically the intermembrane separation and gap junction distribution. Tissue-scale simulations predict that ID structural heterogeneity leads to significant spatial variation in electrical polarization within the intercellular cleft. Importantly, we found that this heterogeneous cleft polarization regulates conduction by desynchronizing the activation of postjunctional Na+ currents. Additionally, these heterogeneities lead to a weaker dependence of conduction velocity on gap junctional coupling, compared with prior modeling formulations that neglect or simplify ID structure. Further, we found that disruption of local ID nanodomains can either slow or enhance conduction, depending on gap junctional coupling strength. Our study therefore suggests that ID nanoscale structure can play a significant role in regulating cardiac conduction.

Novel Poly(ester urethane urea)/Polydioxanone Blends: Electrospun Fibrous Meshes and Films

In this work, we report the electrospinning and mechano-morphological characterizations of scaffolds based on blends of a novel poly(ester urethane urea) (PHH) and poly(dioxanone) (PDO). At the optimized electrospinning conditions, PHH, PDO and blend PHH/PDO in Hexafluroisopropanol (HFIP) solution yielded bead-free non-woven random nanofibers with high porosity and diameter in the range of hundreds of nanometers. The structural, morphological, and biomechanical properties were investigated using Differential Scanning Calorimetry, Scanning Electron Microscopy, Atomic Force Microscopy, and tensile tests. The blended scaffold showed an elastic modulus (~5 MPa) with a combination of the ultimate tensile strength (2 ± 0.5 MPa), and maximum elongation (150% ± 44%) in hydrated conditions, which are comparable to the materials currently being used for soft tissue applications such as skin, native arteries, and cardiac muscles applications. This demonstrates the feasibility of an electrospun PHH/PDO blend for cardiac patches or vascular graft applications that mimic the nanoscale structure and mechanical properties of native tissue.

Controlled self-assembly of plant proteins into high-performance multifunctional nanostructured films

The abundance of plant-derived proteins, as well as their biodegradability and low environmental impact make them attractive polymeric feedstocks for next-generation functional materials to replace current petroleum-based systems. However, efforts to generate functional materials from plant-based proteins in a scalable manner have been hampered by the lack of efficient methods to induce and control their micro and nanoscale structure, key requirements for achieving advantageous material properties and tailoring their functionality. Here, we demonstrate a scalable approach for generating mechanically robust plant-based films on a metre-scale through controlled nanometre-scale self-assembly of water-insoluble plant proteins. The films produced using this method exhibit high optical transmittance, as well as robust mechanical properties comparable to engineering plastics. Furthermore, we demonstrate the ability to impart nano- and microscale patterning into such films through templating, leading to the formation of hydrophobic surfaces as well as structural colour by controlling the size of the patterned features.