Exploring Through-Space Charge Transfer-Mediated Optoelectrochemical Properties of Dual-State Luminescent Aliphatic Polymers and Optoelectronic Responses toward Metal Ions.

Herein, natural-synthetic hybrid dual-state luminescent conducting polymers (DLCPs/DLCP1-DLCP8) possessing significant optoelectrochemical properties are strategically developed by the polymerization of prop-2-enamide, cis-butenedioic acid, 2-acrylamido-2-methylpropane-1-sulfonic acid, and in situ-generated 2-(3-acrylamidopropanamido)-2-methylpropane-1-sulfonic acid alongside the grafting of gum tragacanth. The spectroscopic data of aliphatic DLCPs affirm DLCP7 as the most stable supramolecular assembly endowing optoelectronic properties. Computational calculations identified -C(═O)NH-, -C(═O)OH, -OH, and -SO3H as subluminophores. The absorption spectra, excitation wavelength-/solvent-polarity-/concentration-dependent luminescence, solid state luminescence, aggregation-induced enhanced luminescence, and time-correlated single photon count (TCSPC) studies confirm the occurrence of aggregation-mediated intramolecular through-space charge transfer (ITSCT) in the excited state of DLCP7. Mulliken charge, natural bond orbital, dipole moments, and electronic potential surface analyses confirm the charge donor-acceptor system in DLCP7. Furthermore, the selective optoelectronic response of DLCP7 toward Ca2+/Cu(II) at 438/574 nm is explored using ultraviolet-visible spectra, TCSPC analyses, a dynamic light scattering study, and computational investigations. The chelation-enhanced luminescence and ITSCT inhibition are responsible for turn-on and turn-off detections of Ca2+ and Cu(II), respectively. Cu(II) → Cu(I) reduction in a DLCP7 solution is inferred from electrochemical and spectroscopic analyses. The conductivities of 9.65 × 10-5 S cm-1 (solid state) and 44.35 × 10-5 S cm-1 (solution) in DLCP7 are validated by current-voltage and electrochemical impedance measurements. Again, strong electronic conductivities of 43.89 × 10-5 S cm-1 (solid state)/53.34 × 10-5 S cm-1 (solution) and 45.42 × 10-5 S cm-1 (solid state)/64.81 × 10-5 S cm-1 (solution) are observed in Ca2+-DLCP7 and Cu(II)-DLCP7, respectively.

Synthesis of Intrinsically-Fluorescent Aliphatic Tautomeric Polymers for Proton-Conductivity, Dual-State Emission, and Sensing/Oxidation-Reduction of Metal Ions.

Herein, fluorescent conducting tautomeric polymers (FCTPs) are developed by polymerizing 2-methylprop-2-enoic acid (MPEA), methyl-2-methylpropenoate (MMP), N-(propan-2-yl)prop-2-enamide (PPE), and in situ-anchored 3-(N-(propan-2-yl)prop-2-enamido)-2-methylpropanoic acid (PPEMPA). Among as-synthesized FCTPs, the most promising characteristics in FCTP3 are confirmed by NMR and Fourier transform infrared (FTIR) spectroscopies, luminescence enhancements, and computational studies. In FCTP3, ─C(═O)NH─, -C(═O)N<, ─C(═O)OH, and ─C(═O)OCH3 subluminophores are identified by theoretical calculations and experimental analyses. These subluminophores facilitate redox characteristics, solid state emissions, aggregation-enhanced emissions (AEEs), excited-state intramolecular proton transfer (ESIPT), and conductivities in FCTP3. The ESIPT-associated dual emission/AEEs of FCTP3 are elucidated by time correlated single photon counting (TCSPC) investigation, solvent polarity effects, concentration-dependent emissions, dynamic light scattering (DLS) measurements, field emission scanning electron microscopy images, and computational calculations. The cyclic voltammetry measurements of FCTP3 indicate cumulative redox efficacy of ─C(═O)OH, ─C(═O)NH─/-C(═O)N<, ─C(─O─)═NH+─/─C(─O─)═N+, and ─C(═N)OH functionalities. In FCTP3, ESIPT-associated dual-emission enable in the selective detection of Cr(III)/Cu(II) at λem1/λem2 with the limit of detection of 0.0343/0.079 ppb. The preferential interaction of Cr(III)/Cu(II) with FCTP3 (amide)/FCTP3 (imidol) and oxidation/reduction of Cr(III)/Cu(II) to Cr(VI)/Cu(I) are further supported by NMR-titration; FTIR and X-ray photoelectron spectroscopy analyses; TCSPC/electrochemical/DLS measurement; alongside theoretical calculations. The proton conductivity of FCTP3 is explored by electrochemical impedance spectroscopy and I-V measurements.

Enhanced Nitric Oxide Sensing Performance of Conjugated Polymer Films through Incorporation of Graphitic Carbon Nitride.

Organic field-effect transistor (OFET) gas sensors based on conjugated polymer films have recently attracted considerable attention for use in environmental monitoring applications. However, the existing devices are limited by their poor sensing performance for gas analytes. This drawback is attributed to the low charge transport in and the limited charge-analyte interaction of the conjugated polymers. Herein, we demonstrate that the incorporation of graphitic carbon nitride (g-C3N4) into the conjugated polymer matrix can improve the sensing performance of OFET gas sensors. Moreover, the effect of graphitic carbon nitride (g-C3N4) on the gas sensing properties of OFET sensors based on poly(3-hexylthiophene) (P3HT), a conjugated polymer, was systematically investigated by changing the concentration of the g-C3N4 in the P3HT/g-C3N4 composite films. The obtained films were applied in OFET to detect NO gas at room temperature. In terms of the results, first, the P3HT/g-C3N4 composite films containing 10 wt.% g-C3N4 exhibited a maximum charge carrier mobility of ~1.1 × 10-1 cm2 V-1 S-1, which was approximately five times higher than that of pristine P3HT films. The fabricated P3HT/g-C3N4 composite film based OFET sensors presented significantly enhanced NO gas sensing characteristics compared to those of the bare P3HT sensor. In particular, the sensors based on the P3HT/g-C3N4 (90/10) composite films exhibited the best sensing performance relative to that of the bare P3HT sensor when exposed to 10 ppm NO gas: responsivity = 40.6 vs. 18.1%, response time = 129 vs. 142 s, and recovery time = 148 vs. 162 s. These results demonstrate the enormous promise of g-C3N4 as a gas sensing material that can be hybridized with conjugated polymers to efficiently detect gas analytes.

Green synthesis of microalgae-based carbon dots for decoration of TiO2 nanoparticles in enhancement of organic dye photodegradation.

TiO2 is a well-known semiconductor used widely in the photocatalyst field, but its photocatalytic applications are hampered by a fast electron-hole recombination rate and low visible light absorption due to a wide-band-gap energy. Herein, we present a simple, low cost, and green approach to obtain carbon dots from microalgae, namely microalgae-based carbon dots (MCDs), using an unprecedented microwave-assisted treatment. The MCDs were successfully decorated on the surface of TiO2 nanoparticles. The as-prepared composite exhibited a superior photodegradation of methylene blue, compared with pristine TiO2 (83% and 27%, respectively) under visible light irradiation. The MCDs in TiO2-MCDs serve as electron reservoirs to trap photoinduced electrons and as photosensitizers for the improvement of visible light absorption; both factors play an important role in the improvement of the TiO2 photocatalytic activity. Furthermore, the as-prepared composite photocatalyst also exhibits high photostability and recyclability during the photodegradation of methylene blue. Therefore, this work provides an original approach to the development of environmentally friendly and highly effective photocatalysts for the treatment of various organic pollutants, which can go a long way toward ensuring a safe and sustainable environment.

Can repetitive transcranial magnetic stimulation enhance motor outcomes in cerebral infarct patients?

The effectiveness of repetitive transcranial magnetic stimulation on the post-stroke motor recovery is not apparent. To perform an accurate evaluation, we adjusted for critical factors that determine motor outcomes, including lesion location and the state of the corticospinal tract. We only included patients with cerebral infarct in the corona radiata and with corticospinal tract interruption, apparent on diffusion tensor tractography. We retrospectively enrolled 34 patients whose diffusion tensor tractography corticospinal tract was interrupted by a cerebral infarct. The corticospinal tract state of each patient was evaluated using diffusion tensor tractography. Of the 34 patients whose corticospinal tract was interrupted on diffusion tensor tractography, 12 patients underwent repetitive transcranial magnetic stimulation treatment at the early stage after cerebral infarct (repetitive transcranial magnetic stimulation group). In comparison, 22 patients did not receive repetitive transcranial magnetic stimulation treatment (non-repetitive transcranial magnetic stimulation group). High-frequency repetitive transcranial magnetic stimulation (10 Hz) was performed on the primary motor cortex of the affected hemisphere. At the six month evaluation after the onset of the infarct, motor function was measured in each patient. In both groups, compared to their states during the initial evaluation, significant improvement was found in all measurements of motor function. However, six months after onset, no significant differences between the two groups were found in these measurement scores. When a patient's CST is interrupted, high-frequency repetitive transcranial magnetic stimulation treatment at the early stage after cerebral infarct might have no additional therapeutic effect on motor outcome. Qualified randomized controlled trials are needed to support our findings further.

Combining SWNT and Graphene in Polymer Nanofibers: A Route to Unique Carbon Precursors for Electrochemical Capacitor Electrodes.

It is important to fabricate nanostructured architectures comprised of functional components for a wide variety of applications because precise structural control in the nanometer regime can yield unprecedented, fascinating properties. Owing to their well-defined microstructural characteristics, it has been popular to use carbon nanospecies, such as nanotubes and graphene, in fabricating nanocomposites and nanohybrids. Nevertheless, it still remains hard to control and manipulate nanospecies for specific applications, thus preventing their commercialization. Herein, first, we report unique one-dimensional nanoarchitectures with meso-/macropores, consisting of single-walled nanotubes (SWNTs), graphene, and polyacrylonitrile, in which poly(vinyl alcohol) was employed as a dispersing agent and sacrificial porogen. One-dimensional SWNTs and two-dimensional graphene pieces were combined in the confined interior space of electrospun nanofibers, which led to unique microstructural characteristics such as enhanced ordering of SWNTs, graphene pieces, and polymer chains in the nanofiber interior. Next, the SWNT/graphene-in-polymer nanofiber (SGPNF) structures were converted into carbonized products (SGCNFs) with effective porosity and tunable electrochemical properties. Similar to SGPNFs, the microstructural and electrical properties of the SGCNFs depended on the incorporated amount of SWNT and graphene. At higher SWNT content, the mesopore volume proportion and specific discharge capacitance of the SGCNFs increased by max. 63 and 598%, respectively. The SGCNFs showed strong potential as a high-performance electrode material for electrochemical capacitors (max. capacitance: nonactivated ∼390 F g-1 and activated ∼750 F g-1). Flexible, all solid-state capacitor cells based on SGCNFs were also successfully demonstrated as a model application. The SGCNFs can be further functionalized by various methods, which will impart attractive properties for extended applications.

Synthesis and optimization of chitosan-incorporated semisynthetic polymer/α-Fe2O3 nanoparticle hybrid polymer to explore optimal efficacy of fluorescence resonance energy transfer/charge transfer for Co(II) and Ni(II) sensing.

Initially, four synthetic fluorescent polymers (SFPs) are synthesized from α-methacrylic acid and methanolacrylamide monomers carrying -C(=O)OH and -C(=O)NH subfluorophores, respectively. Among SFPs, ∼1:1 incorporation of subfluorophores in the optimum SFP3 is explored by spectroscopic analyses. Subsequently, chitosan is incorporated in SFP3 to produce five semi-synthetic fluorescent polymers (SSFPs). The maximum incorporation of chitosan in SSFP4 is supported by different spectroscopies. In SSFP4, strong electrostatic interactions among polar functionalities of chitosan and synthetic polymer favor resonance-associated charge transfer (RCT) from SSFP4-(amide) to SSFP4-(canonical). Finally, three hybrid fluorescent polymers (HFPs) are fabricated encapsulating iron-oxide nanoparticle within SSFP4. The maximum proportion of hematite (α-Fe2O3) phase in HFPs is explored by spectroscopic, magnetometric, microscopic, and light scattering studies. HFP2 shows local/RCT/fluorescence resonance energy transfer (FRET) emission at 393/460/570 nm. In HFP2, FRET, RCT, and ratiometric pH-sensing within 3.0-6.5 phenomena are explored by solvent polarity effects, time-correlated single photon counting, quantum yield measurements, alongside I431/I460 vs pH plots. RCT and FRET emissions of HFP2 are utilized for selective sensing of Co(II)/Ni(II) with limits of detection of 4.990 ppb (460 nm)/4.353 ppb (570 nm) and 45.041 ppb (428 nm)/29.617 ppb (527 nm) in organic and aqueous solutions, respectively.

Design and Fabrication of Ultrathin Nanoporous Donor-Acceptor Copolymer-Based Organic Field-Effect Transistors for Enhanced VOC Sensing Performance.

The development of organic field-effect transistor (OFET) chemical sensors with high sensing performance and good air stability has remained a persistent challenge, thereby hindering their practical application. Herein, an OFET sensor based on a donor-acceptor copolymer is shown to provide high responsivity, sensitivity, and selectivity toward polar volatile organic compounds, as well as good air stability. In detail, a polymer blend of N-alkyl-diketopyrrolo-pyrrole-dithienylthieno[3,2-b]thiophene (DPP-DTT) and polystyrene is coated onto an FET substrate via shearing-assisted phase separation (SAPS) combined with selective solvent etching to fabricate the DPP-DTT-based OFET device having an ultrathin nanoporous structure suitable for gas sensing applications. This is achieved via optimization of the film morphology by varying the shear rate to adjust the dynamic balance between the shear and capillary forces to obtain an ultrathin thickness (∼8 nm) and nanopore size (80 nm) that are favorable for the efficient diffusion and interaction of analytes with the active layer. In particular, the sensor presents high responsivities toward methanol (∼70%), acetone (∼51.3%), ethanol (∼39%), and isopropyl alcohol (IPA) (∼29.8%), along with fast response and recovery times of ∼80 and 234 s, respectively. Moreover, the average sensitivity was determined to be 5.75%/ppm from the linear plot of the responsivity against the methanol concentration in the range of 1-100 ppm. Importantly, the device also exhibits excellent long-term (30-day) air and thermal storage stability, thereby demonstrating its high potential for practical applications.

High-Performance Nitric Oxide Gas Sensors Based on an Ultrathin Nanoporous Poly(3-hexylthiophene) Film.

Conjugated polymer (CP)-based organic field-effect transistors (OFETs) have been considered a potential sensor platform for detecting gas molecules because they can amplify sensing signals by controlling the gate voltage. However, these sensors exhibit significantly poorer oxidizing gas sensing performance than their inorganic counterparts. This paper presents a high-performance nitric oxide (NO) OFET sensor consisting of a poly(3-hexylthiophene) (P3HT) film with an ultrathin nanoporous structure. The ultrathin nonporous structure of the P3HT film was created via deposition through the shear-coating-assisted phase separation of polymer blends and selective solvent etching. The ultrathin nonporous structure of the P3HT film enhanced NO gas diffusion, adsorption, and desorption, resulting in the ultrathin nanoporous P3HT-film-based OFET gas sensor exhibiting significantly better sensing performance than pristine P3HT-film-based OFET sensors. Additionally, upon exposure to 10 ppm NO at room temperature, the nanoporous P3HT-film-based OFET gas sensor exhibited significantly better sensing performance (i.e., responsivity ≈ 42%, sensitivity ≈ 4.7% ppm-1, limit of detection ≈ 0.5 ppm, and response/recovery times ≈ 6.6/8.0 min) than the pristine P3HT-film-based OFET sensors.

Controlled Growth of Perovskite Nanocrystals on Nanotubes via a Nanoseeding Intermediate Stage: Toward Novel Optoelectronic Applications.

CsPbBr3 perovskite nanocrystals (CNCs) were densely anchored on multiwalled carbon nanotubes (MWNTs) via a nanoseeding intermediate stage, in which lead-based nuclei are formed on the nanotube surface. After the formation of the intermediate, a cesium precursor was added to promote the growth of CNCs from the surface nuclei and to thereby obtain CNC-decorated MWNT nanohybrids (CMNHs). The morphology and properties of the CMNHs were determined by the reaction temperature employed during their synthesis. Importantly, the use of MWNTs promoted the formation of larger CNCs that emitted intense green light and modified the electronic structure and bandgap energy of the CNCs. Consequently, the CMNHs could function as optoelectronic transducers and exhibit a "turn-on" photocurrent response when exposed to UV light of narrow specific-range wavelengths. In a novel approach for preventing counterfeit products, the CMNHs were used as a light-emitting black ink to create quick-response codes with fake pixels.

Facile Strategy for Modulating the Nanoporous Structure of Ultrathin π-Conjugated Polymer Films for High-Performance Gas Sensors.

Conventional conjugated polymer (CP) films based on organic field-effect transistors (OFETs) tend to limit the performance of gas sensors owing to restricted analyte diffusion and limited interactions with the charge carriers that accumulate in the first few monolayers of the CP film in contact with the dielectric layer. Herein, a facile strategy is presented for modulating the morphology and charge-transport properties of nanoporous CP films using shearing-assisted phase separation of polymer blends for fabricating OFET-based chemical sensors. This approach enables the formation of nanoporous films with pore size and thickness in the ranges of 90-550 and 7-27 nm, respectively, which can be controlled simply by varying the shear rate. The resulting OFET sensors exhibit excellent sensing performance when exposed to NH3 gas, demonstrating a high responsivity (≈70.7%) at 10 ppm and good selectivity toward NH3 over various organic solvent vapors. After a comprehensive analysis of the morphology and electrical properties of the CP films, it is concluded that morphological features, such as film thickness and surface area, affect the sensing performance of nanoporous-film-based OFET sensors more significantly compared to the charge-transport characteristics of the films.

Microgels based on 0D-3D carbon materials: Synthetic techniques, properties, applications, and challenges.

Microgels are three-dimensional (3D) colloidal hydrogel particles with outstanding features such as biocompatibility, good mechanical properties, tunable sizes from submicrometer to tens of nanometers, and large surface areas. Because of these unique qualities, microgels have been widely used in various applications. Carbon-based materials (CMs) with various dimensions (0-3D) have recently been investigated as promising candidates for the design and fabrication of microgels because of their large surface area, excellent conductivity, unique chemical stability, and low cost. Here, we provide a critical review of the specific characteristics of CMs that are being incorporated into microgels, as well as the state-of-the art applications of CM-microgels in pollutant adsorption and photodegradation, H2 evoluation, CO2 capture, soil conditioners, water retention, drug delivery, cell encapsulation, and tissue engineering. Advanced preparation techniques for CM-microgel systems are also summarized and discussed. Finally, challenges related to the low colloidal stability of CM-microgels and development strategies are examined. This review shows that CM-microgels have the potential to be widely used in various practical applications.

Advanced Photocatalysts Based on Conducting Polymer/Metal Oxide Composites for Environmental Applications.

Photocatalysts provide a sustainable method of treating organic pollutants in wastewater and converting greenhouse gases. Many studies have been published on this topic in recent years, which signifies the great interest and attention that this topic inspires in the community, as well as in scientists. Composite photocatalysts based on conducting polymers and metal oxides have emerged as novel and promising photoactive materials. It has been demonstrated that conducting polymers can substantially improve the photocatalytic efficiency of metal oxides owing to their superior photocatalytic activities, high conductivities, and unique electrochemical and optical properties. Consequently, conducting polymer/metal oxide composites exhibit a high photoresponse and possess a higher surface area allowing for visible light absorption, low recombination of charge carriers, and high photocatalytic performance. Herein, we provide an overview of recent advances in the development of conducting polymer/metal oxide composite photocatalysts for organic pollutant degradation and CO2 conversion through photocatalytic processes.

Morphology-Dependent Ambient-Condition Growth of Perovskite Nanocrystals for Enhanced Stability in Photoconversion Device.

CsPbBr3 perovskite nanocrystals with two different dimensionalities were synthesized at different temperatures and then integrated as optoelectronic transducers into transistor-type photoconversion devices. Postsynthesis transformation was observed for two-dimensional (2D) nanoplatelets, while the transformation was rarely found in 3D nanocubes. At ambient temperature and pressure, neighboring nanoplatelets made facet-to-facet contact and then fused into larger 2D nanoplatelets (2-5 times) without defects. The coalescence of 2D nanoplatelets at the ambient condition lowered the density of defects at the surface of the nanocrystals and thus could facilitate effective and stable photoconversion behavior in the nanocrystal film integrated into the device. Consequently, the ambient-condition aging of 2D nanoplatelets on device substrate led to 3 times higher retention in photoconversion performance. Importantly, these results provide a new concept of how perovskite nanocrystals can be integrated into a device for enhanced stability in device performance.

Development strategies of conducting polymer-based electrochemical biosensors for virus biomarkers: Potential for rapid COVID-19 detection.

Rapid, accurate, portable, and large-scale diagnostic technologies for the detection of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) are crucial for controlling the coronavirus disease (COVID-19). The current standard technologies, i.e., reverse-transcription polymerase chain reaction, serological assays, and computed tomography (CT) exhibit practical limitations and challenges in case of massive and rapid testing. Biosensors, particularly electrochemical conducting polymer (CP)-based biosensors, are considered as potential alternatives owing to their large advantages such as high selectivity and sensitivity, rapid detection, low cost, simplicity, flexibility, long self-life, and ease of use. Therefore, CP-based biosensors can serve as multisensors, mobile biosensors, and wearable biosensors, facilitating the development of point-of-care (POC) systems and home-use biosensors for COVID-19 detection. However, the application of these biosensors for COVID-19 entails several challenges related to their degradation, low crystallinity, charge transport properties, and weak interaction with biomarkers. To overcome these problems, this study provides scientific evidence for the potential applications of CP-based electrochemical biosensors in COVID-19 detection based on their applications for the detection of various biomarkers such as DNA/RNA, proteins, whole viruses, and antigens. We then propose promising strategies for the development of CP-based electrochemical biosensors for COVID-19 detection.

Influenza-Host Interplay and Strategies for Universal Vaccine Development.

Influenza is an annual epidemic and an occasional pandemic caused by pathogens that are responsible for infectious respiratory disease. Humans are highly susceptible to the infection mediated by influenza A viruses (IAV). The entry of the virus is mediated by the influenza virus hemagglutinin (HA) glycoprotein that binds to the cellular sialic acid receptors and facilitates the fusion of the viral membrane with the endosomal membrane. During IAV infection, virus-derived pathogen-associated molecular patterns (PAMPs) are recognized by host intracellular specific sensors including toll-like receptors (TLRs), C-type lectin receptors, retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs), and nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) either on the cell surface or intracellularly in endosomes. Herein, we comprehensively review the current knowledge available on the entry of the influenza virus into host cells and the molecular details of the influenza virus-host interface. We also highlight certain strategies for the development of universal influenza vaccines.

Effects of Solvent Vapor Annealing on Morphology and Charge Transport of Poly(3-hexylthiophene) (P3HT) Films Incorporated with Preformed P3HT Nanowires.

We systematically studied the influence of solvent vapor annealing on the molecular ordering, morphologies, and charge transport properties of poly(3-hexylthiophene) (P3HT) thin films embedded with preformed crystalline P3HT nanowires (NWs). Solvent vapor annealing (SVA) with chloroform (CF) was found to profoundly impact on the structural and morphological changes, and thus on the charge transport characteristics, of the P3HT-NW-embedded P3HT films. With increased annealing time, the density of crystalline P3HT NWs was increased within the resultant films, and also intra- and intermolecular interactions of the corresponding films were significantly improved. As a result, the P3HT-NW-embedded P3HT films annealed with CF vapor for 20 min resulted in a maximized charge carrier mobility of ~0.102 cm2 V-1 s-1, which is higher than that of pristine P3HT films by 4.4-fold (µ = ~0.023 cm2 V-1 s-1).

Carbon Nanomaterials as Versatile Platforms for Biosensing Applications.

A biosensor is defined as a measuring system that includes a biological receptor unit with distinctive specificities toward target analytes. Such analytes include a wide range of biological origins such as DNAs of bacteria or viruses, or proteins generated from an immune system of infected or contaminated living organisms. They further include simple molecules such as glucose, ions, and vitamins. One of the major challenges in biosensor development is achieving efficient signal capture of biological recognition-transduction events. Carbon nanomaterials (CNs) are promising candidates to improve the sensitivity of biosensors while attaining low detection limits owing to their capability of immobilizing large quantities of bioreceptor units at a reduced volume, and they can also act as a transduction element. In addition, CNs can be adapted to functionalization and conjugation with organic compounds or metallic nanoparticles; the creation of surface functional groups offers new properties (e.g., physical, chemical, mechanical, electrical, and optical properties) to the nanomaterials. Because of these intriguing features, CNs have been extensively employed in biosensor applications. In particular, carbon nanotubes (CNTs), nanodiamonds, graphene, and fullerenes serve as scaffolds for the immobilization of biomolecules at their surface and are also used as transducers for the conversion of signals associated with the recognition of biological analytes. Herein, we provide a comprehensive review on the synthesis of CNs and their potential application to biosensors. In addition, we discuss the efforts to improve the mechanical and electrical properties of biosensors by combining different CNs.

Multifunctional Role of MoS2 in Preparation of Composite Hydrogels: Radical Initiation and Cross-Linking.

This paper describes the multifunctional effect of molybdenum disulfide (MoS2) that enables the rapid and accessible preparation of nanocomposite hydrogels via a bottom-up design. The MoS2 nanoplatelet forms radical species through a redox reaction with persulfate under aqueous conditions while initiating the polymerization of acrylic monomers and providing noncovalent cross-linking points without requiring external stimuli or extra cross-linkers, leading to the formation of hydrogels that are in situ embedded with inorganic flakes. Furthermore, the addition of MoS2 could induce more rigid and elastic networks compared to those in control hydrogels using a typical cross-linker at the same level; for example, 0.08 wt % MoS2 resulted in a composite hydrogel of which the elastic modulus was 2.5 times greater than that from a hydrogel using N,N'-methylenebis(acrylamide) as the showing phase transition during polymerization. The composite hydrogels are self-healable, taking advantage of reversible physical cross-links. Thus, two cut hydrogel strips could be readily rejoined by heating at 70 °C, and the resulting whole strip showed mechanical strength similar to that of the pristine sample before it was cut. This synthetic approach would give way to the modular design of MoS2-containing composite hydrogels.

Correction: Pine cone mold: a toolbox for fabricating unique metal/carbon nanohybrid electrocatalysts.

Correction for 'Pine cone mold: a toolbox for fabricating unique metal/carbon nanohybrid electrocatalysts' by Hyunwoo Han et al., Nanoscale, 2019, DOI: 10.1039/c9nr06794a.