Original Article

New enzyme catalyst consisting of pyrenecarboxaldehyde (PCA) and glucose oxidase (GOx) immobilized on polyethyleneimine and carbon nanotube (CNT/PEI/[PCA/GOx]) is developed with performance and stability evaluations of enzymatic biofuel cell (EBC) using the new catalyst. By employment of PCA, the amount of immobilized GOx increases and electron transfer of CNT/PEI/[PCA/GOx] is facilitated. With that, superior EBC performance, long-lasting stability and excellent catalytic activities are gained. Such results are attributed to effects of (i) electron collection by hydrophobic interactions, (ii) electron transfer by π-conjugated bonds and (iii) enzyme stabilization by π-hydrogen bonds. Validity of such three positive effects is proved by various measurements.

The capability of fabricating lightweight, small and flexible power sources is a key to cope with the increasing demand for smart and ubiquitous energy sources for current and future flexible electronics. We herein report a portable, lightweight and rollable polymer electrolyte membrane fuel cell. Because of its highly thin and flexible design, the device exhibited excellent durability against repetitive bending and easily deformed to any desired shape such as rolled-up or S-shape geometries. In addition, we introduced a portable flexible planar stack that demonstrates real practical applications of these devices.

Supramolecular polymeric materials constitute a unique class of materials held together by non-covalent interactions. Here we report a novel type of supramolecular rubber based on mixing of low molar mass, oligomeric, ABA-triblock copolyacrylates with oppositely charged outer blocks revealing unique mechanical properties. A broad set of materials is reported with systematic variations in triblock copolymer structures revealing insights in the mechanical properties and self-healing ability in correlation with the nanomorphology of the materials.

Recently, it was found that an electronic state can have hidden, site-dependent spin polarization even in non-magnetic materials with inversion symmetry. Our paper provides a new concept, so far not considered, of hidden orbital polarization and a proof that the hidden spin polarization is not the fundamental physical quantity but a secondary quantity that is completely derived from the hidden orbital polarization proposed in our paper. The hidden orbital polarizations can be important in many physical phenomena, including photoemission, current-induced magnetization, magnetic-field-induced currents, etc. The figure illustrates hidden orbital polarizations of Bloch states in diamond whose spin–orbit coupling is negligible (left) and the current-induced antiferromagnetic magnetization in silicon (right).

Bio-realistic flexible artificial synapses integrated with a nanogenerator were demonstrated for self-powered neuromorphic biomedical device applications. Biocompatible (Na_0.5K_0.5)NbO₃ (NKN) was used in both memristors as an artificial synapse and a nanogenerator. Biological synaptic functions were produced in the NKN memristor driven by the NKN nanogenerator. Finally, metaplasticity was implemented in the integrated devices to facilitate bio-realistic functions in the artificial synapse.

Photodynamic therapy is a promising and effective strategy for being trialed for clinical application. However, poor targeting accumulation of traditional nanoprobes in tumor tissues has hindered its clinical use. Herein, ultra-small and highly stable Fe₃O₄@P-NPO/PEG-Glc@Ce6 nanoprobes were developed to improve the tumor-targeting efficiency and photodynamic therapeutic efficacy based on small size effect. The nanoprobes effectively prolong the residence time in the tumor region, reduce the accumulation in vital organs and significantly inhibit the growth of tumors in vivo. The successful application of small size effect in nanoprobes provides a new path for clinical therapies and translation in the near future.

By thermally evaporated through a tilted shadow mask, metal vapor scatters and lands on the substrate to form an ultrathin layer. Absence of screening effect from bulk metal enables direct measurement of the buried dipole formed at the organic/metal interface. It is found that polar species of the organic, Fermi-level pinning and interface morphology can all influence the dipole orientation. The proposed method provides a quick and easy approach to assess interfacial materials and design electrode interfaces in organic electronic devices.

Nano-rough surface offered by vertical graphene with nano-hill type morphology of corresponding peaks and valleys. These nano-hills result in the formation of smaller sized nitrogen bubbles when utilized for the oxidation of hydrazine. Due to their low adhesion force on the electrode surface, these bubbles leave the surface quickly and hence render the superaerophobic property to vertical graphene nano-hills.

Shape transformation of hydro/organo Janus films: A hydro/organo Janus copolymer film has been designed and fabricated via a novel strategy, an unconventional one-step interfacial polymerization of the immiscible hydrophilic vinyl monomer solution and hydrophobic vinyl monomer solution. Under the binary cooperative effect of the hydrogel network and organogel network, the Janus film is able to work both in the aqueous solutions and organic solvents, and exhibit excellent shape-transformation performance, such as bidirectional and site-specific bendings.

Phase separation based on simultaneous polymerization and crystallization generated the segregated composite of organic crystals and conductive polymers in submicrometer scale. The phase-segregated structure of redox-active conductive polymer and quinone crystal showed the enhanced charge-storage properties based on the smooth redox reaction.

A bifunctional scaffold was successfully prepared by in situ growth of MoS₂ nanosheets on the 3D-printed bioceramic scaffolds via a facile hydrothermal process. The prepared scaffolds exhibit an excellent capability for both tumor therapy and tissue regeneration, offering a promising clinical strategy for effective treatment of tumor-induced tissue defects.

The BN-carbon separator was first demonstrated as a multifunctional trilayer membrane to facilitate the better electrochemical performances of Li-S batteries and protect a Li anode from unexpected side reactions. Unlike the previous approach to block the polysulfides only within the cathodic side, the concept of placing a BN interlayer on anodic side showed promising results in achieving high electrochemical performances of Li-S batteries and stable operations of lithium metal at a high current density.

Here we report an inexpensive, solution-phase growth of cm-scale single crystals of variable composition Cs_xFA_1−xPbI_3−yBr_y (FA=formamidinium, x=0–0.1, y=0–0.6), which exhibit improved phase stability compared to the parent α-FAPbI₃ compound. High-carrier mobility–lifetime product of up to 1.2 × 10⁻¹ cm² V⁻¹ and a low dark carrier density, combined with the high absorptivity of high-energy photons by Pb and I, allow the sensitive detection of gamma radiation. With stable operation up to 30 V, these novel perovskite materials have been used in a prototype of a gamma-counting dosimeter.

Novel digital memory devices were fabricated with a new photo-patternable polyimide (PI), poly(hexafluoroisopropylidenediphthalimide-4-cinnamoyloxytriphenylamine (6F-HTPA-CI). The finely patterned PI device cells demonstrated excellent programmable nonvolatile memory characteristics in three different modes (unipolar permanent memory, and unipolar and bipolar flash memories). Overall, this photopatternable polymer is very suitable for future energy-efficient, faster speed and high density nonvolatile memory devices in highly integrated systems.

Inspired by mussel chemistry, a novel polydopamine–polyacrymide hydrogel simultaneously possesses super stretchability, stimuli-free self-healing properties, cell affinity and tissue adhesiveness. The current hydrogel lasts its adhesiveness for a long term, and can be repeatedly adhered on/stripped from a variety of substrates. The hydrogel can host various nano-building blocks and be tuned to magnetic and conductive hydrogels with above-mentioned properties.

A self-protected nanovehicle with peptide-mediated core/satellite/shell structure was constructed for precise imaging of protease cathepsin B (Cat B) in situ and subsequent Cat B-responsive drug release. The self-protected nanovehicles have demonstrated excellent resistant ability to nonspecific enzymolysis, thereby keeping the embedded peptide-based molecular probes with core/satellite structure intact until reaching the target organelle.

Schematic illustration of nanoformulated curcumin accelerates wound healing. (a) Curcumin nanoformulation through electrospinning greatly enhances its solubility. (b) Topically applied Curcumin/Gelatin nanofibrous mat releases bioactive curcumin to mobilize wound site fibroblasts by enhancing both cell proliferation and migration, a process partially mediated by Dickkopf-related protein-1-regulated Wnt/β-catenin pathway signaling. In the mean time, fibroblasts decreased the expression of monocyte chemoattractant protein-1, leading to lasting inhibition of inflammatory response during the healing process. As a result, wound environment turns out to be more in favor of physiological healing, with faster re-epithelialization, granulation tissue formation, as well as collagen deposition and matuaration from proliferative fibroblasts.

Magneto-core–shell nanoassemblies by loading μ-oxo-bridged Fe complex (Fe(salen) (core)) inside PCL-b-PPy block copolymers (shell) are fabricated, without the use of common magnetites and toxic solvents. By taking a surface functionalization with natural biomolecules (bovine serum albumin/gum arabic (BSA/GA)), the nanoassemblies endow to hold tunablity of core-size and magnetism, biocompatibility, and colloidal stability. Moreover, distinguishing their multifunctional features of cancer targeting include magneto-guided drug delivery, MRI, and triggered hyperthermia in responsive to multi (magnetic, thermo, and pH) stimuli, which allow them a promising potential for a wide-variety of ‘minimally-invasive’ theranostic clinics, as an alternative candidate to conventional magnetite-based anticancer targeting.

Novel magnetophoretic device resembling a spider web network, being integrated with planar Hall resistance sensor, has been developed for the simultaneous concentric transportation and monitoring of superparamagnetic streptavidin-loaded cargos (particles). The multilayer sensor and permalloy network tracks have been fabricated by successive micropatterning processes of film deposition and photolithography. The transporting particles are precisely manipulated on the magnetic tracks towards the sensor by an external magnetic field, where the sensor signal varies with the accumulated particle number. This effective collection and monitoring platform could open novel bioassays overcoming limitation of Brownian transportation of biomolecules to the sensor surface.

The electrochemical activity of Ni²⁺/³⁺ redox couple in the mixed-polyanionic framework Na₄Ni₃(PO₄)₂(P₂O₇) is reported for the first time. The application of a carbon coating and the use of an ionic liquid-based electrolyte enable the reversible Na⁺ (de-)insertion in the host structure accompanied by the redox activity of Ni²⁺/³⁺ at operating voltages as high as 4.8V vs. Na/Na⁺. These results represent an important step towards the realization of Ni- based mixed polyanionic compounds with improved electrochemical activity and pave ways for the discovery of new Na-based cathode materials and the formulation of Na-ion batteries with very high operating voltages.