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Nanomaterials-based immunochromatographic assays (ICAs) have gained great commercial success in real-life point-of-care testing (POCT). Exploring novel carriers of ICAs with improved signaling and sustained activity favors the development of sensitive POCT. Herein a potent signal biotag, colored Staphylococcus aureus (SA), was created for ICA carriers through a mild self-assembly strategy, providing high luminance and abundant specific binding sites for immobilization of monoclonal antibodies (mAbs). The biocompatible SA-dyes (SADs) retained both an intact surface structure for mAbs labeling (Fc portion) and the superior bioactivity of immobilized mAbs (affinity constant was about 109 M-1), thus waiving the intrinsic limitations of traditional nanomaterials and endowing high sensitivity. Proof-of-concept was demonstrated by employing Congo red- or/and fluorescein isothiocyanate-embedded SA (SACR, SAFITC, and SACR-SAFITC) as ICA carriers to detect zearalenone (ZEN) through colorimetric or/and fluorimetric signals. Furthermore, the ICAs satisfied the clinical requirement perfectly, including limit of detection (0.013 ng/mL, which was at least an 85-fold improvement over that of traditional gold nanoparticles-based ICA), linearity (R2 > 0.98), reproducibility (RSD < 8%), selectivity, and stability. Importantly, the proposed biosensors could be well-applied in four real samples for ZEN monitoring with satisfactory recoveries, correlating well with the results from liquid chromatography-tandem mass spectrometry (LC-MS). This work also proved a universal design for tailoring coloration bands for SAD-ICA detection of multiple analytes.

To investigate the ability of critical care nurses to identify pressure injury and incontinence-associated dermatitis and analyse the possible influencing factors.Cross-sectional survey.This study was conducted at 24 hospitals across 12 provinces in China. A self-made electronic questionnaire was used. Nurses identified and judged injuries according to the information provided.The average identification score for pressure injury and incontinence-associated dermatitis was 9.00 ± 3.51 points, and only 2.16% of nurses scored ≥16 points. The average correct identification rate for pressure injury and incontinence-associated dermatitis was 45%. The correct identification rate for stage 1 pressure injury was the highest, while those for stage 3, stage 4, deep tissue pressure injury and unstageable pressure injury were all lower than 50%; incontinence-associated dermatitis was also easily misjudged. Nurses' educational backgrounds, professional titles, job positions, hospital levels and learning frequency were the factors that affected their ability to identify pressure injury and incontinence-associated dermatitis.

To solve the problem that the voltage and current of power consumption in key areas of urban distribution networks exceed the safe range of power consumption, research on power consumption security in key areas of urban distribution networks is carried out. Under the condition of the feeder N-1 criterion, the maximum power supply capacity model of the urban distribution network is established. The theory of feeder interconnection is introduced to determine the security region of the distribution network. The security response is carried out for power users in key areas, and a new power security scheme is proposed. The example proves that the application of the safety guarantee scheme can control the voltage and current in the key areas of urban distribution networks within a safe range, and improve the overall operation safety of urban distribution networks.

Porphyrins are a class of conjugated molecules that structurally and functionally resemble natural photosynthetic and enzymatic chromophores. Crystalline solids self-assembled from anionic and cationic porphyrins yield a new class of multifunctional optoelectronic micro- and nanomaterials. In this article, we provide details on the concept of binary ionic self-assembly (ISA) and ionized forms of porphyrins, as well as formation of hierarchical structures, including nanotubes, rods and ribbons, sheets, and three-dimensional clover-like shapes, spheres, and sheaf-like structures. We summarize key physical properties from ultraviolet–visible characterizations of J-aggregate, exciton delocalization and extended π–π stacking, and related electronic and light-harvesting properties of the structures. Depending on the molecular subunits, the functionalities of the ISA materials are altered. These ISA nanostructures possess attractive light-harvesting and charge- and energy-transport functionalities and allow access to a novel class of nanomaterials with potential for applications in sensors, photovoltaics, photocatalysis, and solar power.

Nanomaterials-based immunochromatographic assays (ICAs) have gained great commercial success in real-life point-of-care testing (POCT). Exploring novel carriers of ICAs with improved signaling and sustained activity favors the development of sensitive POCT. Herein a potent signal biotag, colored

Background Coronavirus disease 2019 (COVID-19) is a public health emergency of international concern and has caused traumatic experience for nurses worldwide. However, the prevalence of depression and anxiety symptoms in nurses, and how psychosocial factors influence nurses in this public crisis are unknown. Objectives To determine the effect of COVID-19 on the mental health of nurses and the prevalence of anxiety and depression symptoms among nurses in China during the outbreak. Design A cross-sectional study. Settings and participants A total of 3,228 nurses in Sichuan Province and Wuhan City were selected by convenience sampling. All participants were invited to complete the questionnaire through WeChat from January 27 to February 3, 2020. Methods A self-reported questionnaire combining depression and anxiety scale was used to collect data anonymously. Binary and multivariate logistic regression was applied to measure the odds of psychosocial factors of anxiety and depression and perceived health, respectively. Results The total incidence of depression (34.3%) and anxiety (18.1%) during the COVID-19 outbreak was lower than that during the SARS outbreak; however, the rate of depression in our study (47.1%) was high and similar in a recent study (50.4%) about the health care workers exposed to COVID-19 in China. The results indicated that COVID-19-related stress, relationship quality with family, and demographic characteristics were associated with depression, anxiety, and perceived health status. Furthermore, the prevalence of depression was similar between nurses working in low-risk COVID-19 wards was as high as working in high-risk COVID-19 wards (OR, 1.078; 95% CI, 0.784–1.481). Conclusions Our study revealed the high prevalence of depression and anxiety among nurses during the outbreak of COVID-19. COVID-19 factors and psychosocial factors were associated with mental health of nurses. The results suggest that hospitals should implement effective mental health promotion programs focused on occupational safety and family support to improve the well-being of nurses.

One of the major concerns in the application of nanocarriers in biosensing is the impair of the recognition molecules bioactivity loaded on their surfaces due to harsh and laborious cross-linking and random orientation, resulting in unsatisfactory sensitivity. Herein, we proposed a novel immunochromatographic test strip (FNS-ag-DICTS) by taking advantage of the antigen (ag) modified Fe

A prussian blue nanocubes decomposition-assisted signal amplification strategy for competitive lateral flow immunoassay (PBNCD-SALFIA) was innovatively proposed to analyze aflatoxin B

A sensitive photothermal immunochromatographic test strip (PITS) for the detection of deoxynivalenol (DON) was developed using flower-like gold nanoparticle-deposited manganese dioxide nanocarrier (FMD-G NC) labeled antibodies (Abs) as the photothermal-sensing probe. FMD was used as a template to deposit small gold nanoparticles (GNPs) to synthesize FMD-G NC with large specific surface area and significant photothermal conversion property. The FMD-G-Ab probe was competitively captured by DON target and antigen coated on test line (T-line), forming colorimetric signals under naked eyes and photothermal signals under an 808 nm laser. Under optimal conditions, the PITS exhibited sensitive and specific detection of DON from 0.19 ng mL−1 to 12 ng mL−1 with detection limits of 0.013 ng mL−1, which were over 15-fold and 58-fold more sensitive than visual FMD-G-ITS and traditional GNPs-ITS. In addition, the novel FMD-G-PITS possessed a universal applicability, which could be well applied in green bean, corn, and millet.

Conventional immunochromatographic assays (ICAs) based on gold nanoparticles (GNPs) suffer from the disadvantage of low sensitivity. In this work, a highly sensitive ICA based on polydopamine coated zirconium metal-organic frameworks labeled antibodies (ZrPA-Ab) as a novel probe was developed for visual determination of deoxynivalenol (DON). The ZrPA was synthesized via an oxidative self-polymerized assembly (OPMA) strategy using porphyrin functionalized zirconium metal-organic frameworks (Zr-MOFs, MOF-525) and polydopamine (PDA). The Abs could directly attach to the ZrPA surface owing to the large specific surface area, excellent water-stability and bio-compatibility of the ZrPA, on this basis, a sensitive, precise and reliable immunoassay method can be developed for rapid and selective detection of DON. Under optimized conditions, a non-linear calibration curve was obtained in the range of 0–50 ng/mL DON concentration with an IC50 of 1.22 ng/mL, and the visual detection limit was 0.18 ng/mL, which was about 8-times more sensitive than that of the conventional GNPs-based ICA. Finally, the proposed ZrPA-ICA was successfully applied for the detection of DON in pig hind legs meat, green bean, maize and millet samples, revealing the feasible and reliable application of this biosensor in different food matrices. Thus, this work broadens the possibilities for the use of MOFs as a novel labeling carrier in immunoassays.

Background: Data regarding critical care for patients with severe COVID-19 are limited. We aimed to describe and analyse the clinical course, multi-strategy management, and respiratory support usage for the severe COVID-19 at the provincial level. Methods: Using data from Sichuan Provincial Department of Health and the population-based multicentre cohort study, all microbiologically confirmed COVID-19 patients in Sichuan who met the national severe criteria were included from January 16 to March 15, 2020. All patients were followed-up from the day of inclusion, noted as Day one (D1), until discharge, death, or the end of the study. Findings: Out of 539 COVID-19 patients, 81 severe cases (15·0%) were identified. The median (IQR) age was 50 (39-65) years, 37% were female, and 53·1% had chronic comorbidities. All severe cases were identified before requiring mechanical ventilation. Among the five predefined criteria for severe illness, low PaO2:FiO2 ratio (

Herein, a label-free and dual-readout immunochromatographic test strip (ITS) for the sensitive detection of Escherichia coli (E. coli) O157:H7 by taking advantages of the strong capture ability of Fe

Gold nanoparticles (AuNPs)-based lateral flow assay (LFA) enables a rapid detection of tetracycline (TET) in food samples but suffers from low sensitivity. Herein, metal-polydopamine framework (MPF), as a label, was employed to load monoclonal antibodies (mAbs) directly as the probe in LFA for highly sensitive sensing of TET. Combining zeolitic imidazolate framework (ZIF-67) and polydopamine (PDA), a stable MPF with large size, well water-dispersible, excellent affinity and optical properties was prepared through a versatile layer-by-layer assembly (LLA) strategy. Under optimized conditions, the biosensor (MPF-LFA) exhibited a great linear relationship in the range of 0.09–6 ng/mL and a detection limit of 0.045 ng/mL for TET detection, which was over 66-fold more sensitive than traditional AuNPs based LFA. Furthermore, the MPF-LFA was successfully applied to the screening of TET in fish, chicken, milk and shrimp samples with satisfied recoveries from 91% to 114%.

One of the major concerns in the application of nanocarriers in biosensing is the impair of the recognition molecules bioactivity loaded on their surfaces due to harsh and laborious cross-linking and random orientation, resulting in unsatisfactory sensitivity. Herein, we proposed a novel immunochromatographic test strip (FNS-ag-DICTS) by taking advantage of the antigen (ag) modified Fe2O3 nanostructures (FNSs) as new signal tags and goat anti-mouse IgG labeling on the detection line instead of ag, which was used for sensitive detection of aflatoxin B1 (AFB1). The fabricated FNS-ag can orientate the Fab region of monoclonal antibodies (mAbs), waiving the intrinsic limitations of traditional nanomaterials labeled mAbs. Under optimal conditions, FNS-ag-DICTS possessed excellent specificity and a wide detection range, with a visual limit of detection (vLOD) of 0.0125 ng mL−1. In addition, the biosensor successfully detected AFB1 in peanut, green bean and corn, with an average recovery rate of 82.8–124.9%.

Abnormal levels of biothiols such as cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) are associated with many pathological diseases. The demand for bulky and costly apparatuses represents a big impediment for point-of-care testing of biothiols. Herein, we developed a novel photothermal sensor for biothiols based on the formation of polydopamine nanoparticles (PDA NPs) using a thermometer as readout. A zeolitic imidazolate framework (ZIF-67) was first fabricated through a facile one-pot strategy. Then dopamine (DA) was immediately polymerized into PDA NPs with excellent photothermal effects (PETs) in the presence of the ZIF-67. Biothiols could disintegrate ZIF-67 by substituting ligands, causing the reaction between biothiols and cobalt ions to form complexes, and release 2-methylimidazole (2MIM) that can slowly oxidize DA, thereby "weakening" the PETs signal, which enabled us to convert biological signals into temperature signals. Therefore, the quantitative detection of Cys, Hcy and GSH can be achieved by recording temperature changes, with detection limits as low as 0.158 μM, 0.181 μM and 0.207 μM, respectively. Furthermore, the photothermal sensor has been applied in detection of biothiols in fetal bovine serum with satisfactory recovery rates, correlating well with the results by standard Ellman method, signifying its promising potential in integrated biological detection system.

Highlights • A label-free, non-paired antibodies dependent biosensor was constructed. • (+) AuNPs were employed to generate signal and capture bacteria in the new LFS. • This work possesses a desirable universality for other pathogens., Gold nanoparticles (AuNPs)-based lateral flow strip (LFS) enables a quick screening of foodborne bacteria in point-of-care (POC) diagnostics but suffers from the cumbersome labeling of antibodies and poor sensitive performance. Here, we innovated a label-free immunoassay to detect pathogenic bacteria by introducing diversely positive charges functionalized AuNPs ((+) AuNPs). The (+) AuNPs can be loaded on negatively charged bacteria via electrostatic interaction, leading to a color labeling to target bacteria. Afterward, the (+) AuNPs-bacteria complex can be specifically captured by monoclonal antibody (McAb) immobilized on test (T)-line. Under optimum conditions, the proposed LFS exhibited a lowest detectable concentration of 103 CFU/mL for Salmonella enteritidis (S. enteritidis) and could be well applied in drinking water, lettuce and pork samples. Moreover, this novel (+) AuNPs-LFS possessed a universal applicability, which could also be used for detecting Escherichia coli O157 (E. coli O157) with a superior sensitivity (104 CFU/mL) and specificity.

A prussian blue nanocubes decomposition-assisted signal amplification strategy for competitive lateral flow immunoassay (PBNCD-SALFIA) was innovatively proposed to analyze aflatoxin B1 (AFB1) in foodstuffs. The signal was amplified on account of the PBNCs can degrade and fade under alkaline condition, which could weak the color of the test- and control-lines, thereby improving the sensitivity of the sensor. The strategy was technically-simple, just using NaOH as an amplifier can realize signal amplification in the competition assay. Under optimized conditions, the enhanced strip exhibited excellent specificity and sensitivity in AFB1 monitoring with a detection limit of 23 pg/mL, which was approximately 4- and 8-folds lower than those of PBNCs-LFIA (90 pg/mL) and conventional gold nanoparticles-LFIA (175 pg/mL), respectively. Taking the advantage of the color-fading, this platform revealing the lowest detectable concentration of 0.184, 0.368 and 0.184 μg/kg for AFB1 in corn, peanut and pumpkin seed within 58 min, separately, showing reliable results.

Multiple mycotoxins may co-occurred in a single product and cause serious threats to public health. Herein, a multiplex immunochromatographic assay (mICA) was developed based on novel α-Fe2O3 nanocubes (FNCs) as signal tags for the simultaneous detection of deoxynivalenol (DON) and aflatoxins B1 (AFB1). The FNCs with eminent water-dispersibility and stability were synthesized by a one-step hydrothermal process, which can rapidly label monoclonal antibodies (mAbs) to form FNCs-mAb probe. Under optimal experimental conditions, the visual limit of detection for DON and AFB1 were 0.18 ng/mL and 0.01 ng/mL, respectively, which were at least 2-fold improvement compared with the traditional gold nanoparticles based mICA. Furthermore, DON and AFB1 residual in mung bean, millet and corn were successfully detected by the proposed biosensor, and the average recovery rates were 93.3%–128.3%. Thus, this work indicated that the developed FNCs-mICA provided a sensitive, rapid and reliable on-site simultaneous detection of multiple mycotoxins.

Herein, a label-free and dual-readout immunochromatographic test strip (ITS) for the sensitive detection of Escherichia coli (E. coli) O157:H7 by taking advantages of the strong capture ability of Fe3O4@CuS nanostructures (NSs) towards bacteria and their ultrahigh photothermal effects (PTEs) was reported. Especially, without the customarily antibody (Ab)-labeled probe, Fe3O4@CuS NSs could be adsorbed onto the surfaces of bacteria to form Fe3O4@CuS-bacteria conjugates and then trapped by immobilized Abs on the test line (T-line), forming a characteristic yellow band. After direct immunoreactions, the PTEs of Fe3O4@CuS NSs endowed T-line to be irradiated by an 808 nm infrared light, obtaining satisfactory sensitivity and accuracy. Under optimal conditions, E. coli O157:H7, as low as 103 and 102 CFU/mL, could be monitored in colorimetric and photothermal modes. Additionally, E. coli O157:H7 was successfully detected in beef, chicken, milk and honey samples by this proposed platform with a recovery of 80–120%.

Fluorescence-based lateral flow immunoassay (FLFIA) is a prospective technology in detecting tetracycline (TET). However, the existing fluorescent materials (FMs) often require cross-linkers to bind with antibodies (Abs) to form FLFIA FM-Ab probe, which complicates the modification process and may affect the fluorescence intensity of FMs. Herein, the rhombic-like Al nanosupporter (RAlNS) was prepared via a one-step hydrothermal method and used for designing fluorescence nanosupporter for FLFIA to detect TET in real samples. The RAlNS not only possessed excellent water stability, strong fluorescence intensity and favorable thermal stability, but also could adsorb Abs to obtain FMs-Ab probe by simple centrifugation. Under optimal conditions, the limit of detection (LOD) of RAlNS-FLFIA was 0.0516 ng/mL (n = 3), which was 18 times lower than traditional colloidal gold-based LFIA. Meanwhile, the proposed sensor also exhibited high specificity for TET against other antibiotics. Furthermore, the RAlNS-FLFIA was successfully applied to the detection of TET in beef, chicken, milk and honey samples, separately, which demonstrated a significant recovery of 80.40%―112.05%. The novel RAlNS-FLFIA provided great potential for the detection of various analytes in food analysis.

The polymerization and carbonization of coal tar was carried out at different temperatures from 633 to 1873 K using aluminium trichloride as catalyst. The polymerization degree, microstructures and optical texture of samples were analyzed by thermogravimetry, X-ray diffraction, Raman spectroscopy and polarized light microscopy. Results indicated that aluminium trichloride accelerated dehydrogenation during the polymerization of coal tar, and increased the toluene-insoluble fraction and carbonization yield. The presence of aluminium trichloride in the polymerized coal tar affected the microstructure of the coke by the formation of a quasi-isotropic structure.

We report generation of modular, artificial light-harvesting assemblies where an amphiphilic diblock copolymer, poly(ethylene oxide)-block-poly(butadiene), serves as the framework for noncovalent organization of BODIPY-based energy donor and bacteriochlorin-based energy acceptor chromophores. The assemblies are adaptive and form well-defined micelles in aqueous solution and high-quality monolayer and bilayer films on solid supports, with the latter showing greater than 90% energy transfer efficiency. This study lays the groundwork for further development of modular, polymer-based materials for light harvesting and other photonic applications.

Aims: Recently, the further understanding of gastrointestinal stromal tumor (GIST) and development of diagnosis and treatment methods have led to an increase in diagnosed cases. Patients may present with acute abdomen, perforation or peritonitis, and acute intestinal obstruction. This work aims to investigate the clinical treatment and nursing methods of GIST patients with an acute abdomen symptom. Methods: A retrospective analysis was conducted for the treatment and nursing care of 45 GIST cases, in which the primary symptom was acute abdomen. The patients were admitted at the General Surgery of Sichuan University from January 2008 to January 2011. Results: A total of 45 GIST patients (28 males and 17 females) were involved in the research, which included 29 stomach tumor cases (64.4%), 11 small intestine-related cases (24.5%), 3 colon-related cases (6.7%), and 2 rectum-related cases (4.4%). Among these cases, 11 were diagnosed with acute intestinal obstruction (24.5%), 27 with acute gastrointestinal hemorrhage (60.0%), and 7 with abdominal hemorrhage caused by tumor rupture (15.5%); 41 cases underwent surgical treatment, improved after perioperative care, and were subsequently discharged from the hospital; another 4 cases with advanced tumors were treated with oral imatinib mesylate as neoadjuvant therapy, which eventually led to a partial relief. Conclusions: No clinical specificity regarding GIST exists. Thus, GIST is prone to misdiagnosis and/or missed diagnosis. Early diagnosis and treatment increase the prognosis of patients. The integrity of the treatment and nursing care can effectively and safely help patients during the perioperative period.

A simple and novel immunochromatographic assay (ICA) was developed for specific and sensitive determination of ochratoxin A (OTA) employing microorganism (MO) as reducers and carriers. In this work, microorganism loaded gold nanoparticles (MO@AuNPs) composites were synthesized by reacting Yeast/Lactobacillus (LAB) with HAuCl4 via biosorption and subsequent bioreduction. The synthesis conditions (pH and reaction time) and main parameters (morphology, diameter and functional groups) of MO@AuNPs were investigated. Owing to the large sizes (about 2 μm) and high adsorption abilities of MO@AuNPs, the few antibodies were labeled, resulting a lower detection limit for ICA. After optimization, the linear detection of OTA using MO@AuNPs-based immunoassay ranged from 0.1 to 1.6 ng/mL, and the visual limit of detection (vLOD) was 0.1 ng/mL, which was nearly 8-fold lower than traditional AuNPs-ICA. Meanwhile, the proposed strategy also possessed high specificity for OTA against other mycotoxins. The applicability of the platform was successfully assessed through the detection of OTA in rice, corn, ginger and green bean samples. The results indicated that these creative sensing elements are promising alternatives and bring an innovative inspiration for biological detections.

The pH of the solution from which a cooperative binary ionic material is formed can alter the charges of the organic anions and cations and thus the composition, crystal structure, and properties of the materials obtained by ionic self-assembly. In particular, this pH/charge effect provides a means of synthetic control over the properties and morphologies of ionic solids formed from cationic and anionic porphyrins. In the case of titration of an axial hydroxide ligand of the metal of the porphyrin to water, the charge increases by +1 with little perturbation of the molecular structure of the constituent porphyrin anion or cation. The structure of the material is thus altered without significantly altering the electronic structure of the porphyrin tecton. These novel porphyrin-based ionic materials have potential applications as catalysts, photocatalysts, and optoelectronic and sensing materials.

Cu reticulated mesh and stochastic open cellular foams were fabricated by additive manufacturing using electron beam melting. Fabricated densities ranged from 0.73 g/cm(3) to 6.67 g/cm3. The precursor Cu powder contained Cu(2)O precipitates and the fabricated components contained arrays of Cu(2)O precipitates and interconnected dislocation microstructures having average spacings of similar to 2 mu m, which provide hardness values similar to 75% above commercial Cu products. Plots of stiffness (Young's modulus) versus density and relative stiffness versus relative density were in very close agreement with the Gibson-Ashby model for open cellular foams. These open cellular structure components exhibit considerable potential for novel, complex, multi-functional electrical and thermal management systems, especially complex, monolithic heat exchange devices. (C) 2011 Elsevier B.V. All rights reserved.

Mesoporous carbon (MoC), prepared by the template method from phenol resin, commercial mesoporous carbon fiber (ACF) and microporous activated carbon (MiC) were heat-treated under 1200 °C in nitrogen. The samples before and after high temperature heat treatment (HTT) were used as electrodes in 30% KOH electrolyte for supercapacitor. The structure and electrochemical properties of these samples were characterized by X-ray diffraction (XRD), galvanotactic charge–discharge, cyclic voltammetry (CV) and electrochemical impedance spectra, respectively. Results showed that HTT caused a remarkable increase of mesoporous ratio in texture accompanied with a significant reduction of surface area. After HTT, the layer–layer space among graphite crystallite decreased and the degree of graphitization was improved. The capacitance values of mesoporous carbons increased and a more stable tendency for specific capacitance was obtained compared with the contrary performance of MiC-1200. The cyclic voltammetry of the samples at different sweep rates was close to the rectangular shape, which represented the lower ESR and higher power density. It was also found that high temperature treatment could improve the electrical conductivity and decrease the impedance of the electrode remarkably. The improved specific capacitance and the better conductivity of mesoporous carbons could be ascribed to the expanding and reorganization of crystallite structure as well as increase of mesopore ratio.

To solve the problem of color controlling in chemical coloring on stainless steel, a one-step process, combining chemical coloring and electrolytic hardening into single stage by concurrently introducing low cathodic current, was developed. The effects of the cathodic current density were studied, and the surface morphologies, compositions and properties of the colored films were characterized with the help of scanning electron microscopy (SEM). These results show that the one-step process not only simplifies coloring process but also is superior in coloring controllability and reproducibility compared with the traditional process.

Crystalline solids self-assembled from anionic and cationic porphyrins provide a new class of multifunctional optoelectronic micro- and nanomaterials. A 1 : 1 combination of zinc(II) tetra(4-sulfonatophenyl)porphyrin (ZnTPPS) and tin(IV) tetra(N-methyl-4-pyridiniumyl)porphyrin (SnTNMePyP) gives porphyrin nanosheets with high aspect ratios and varying thickness. The room temperature preparation of the nanosheets has provided the first X-ray crystal structure of a cooperative binary ionic (CBI) solid. The unit cell contains one and one-half molecules of aquo-ZnTPPS(4-) (an electron donor) and three half molecules of dihydroxy-SnTNMePyP(4+) (an electron acceptor). Charge balance in the solid is reached without any non-porphyrinic ions, as previously determined for other CBI nanomaterials by non-crystallographic means. The crystal structure reveals a complicated molecular arrangement with slipped π-π stacking only occurring in isolated dimers of one of the symmetrically unique zinc porphyrins. Consistent with the crystal structure, UV-visible J-aggregate bands indicative of exciton delocalization and extended π-π stacking are not observed. XRD measurements show that the structure of the Zn/Sn nanosheets is distinct from that of Zn/Sn four-leaf clover-like CBI solids reported previously. In contrast with the Zn/Sn clovers that do exhibit J-aggregate bands and are photoconductive, the nanosheets are not photoconductive. Even so, the nanosheets act as light-harvesting structures in an artificial photosynthesis system capable of reducing water to hydrogen but not as efficiently as the Zn/Sn clovers.

Novel platinum nanowheels were synthesized by the reduction of aqueous platinum complex with ascorbic acid in the presence of disk-like bicelles. The platinum nanowheels possess thickened centers and flared edges that are connected by dendritic platinum nanosheets. This structural complexity can be attributed to the inhomogeneous micro-environment of the templating bicelles consisting of a central bi-layer region and a high curvature rim. The formation mechanism of the nanowheels was investigated by imaging nanostructures at different stages of the reaction. The templating bicelles were also imaged by TEM with the aid of negative staining. The variation of reaction parameters including platinum concentration, temperature, and total concentration of surfactants (CTAB + FC7) led to other types of platinum nanostructures, such as circular dendritic nanosheets with a tunable diameter and rectangular dendritic nanosheets. Interestingly, under irradiation by a TEM electron beam, the dendritic nanosheet portion of the nanowheels transforms into a metastable holey sheet. In addition, the platinum nanowheels have an electrochemical active surface area comparable to that of ETEK platinum black and thus are expected to have potential applications in catalysis.

Individual single-walled carbon nanotubes (SWCNTs) have interesting optoelectronic properties that have shown potential uses in photovoltaics, transparent conducting films and sensing devices. However, due to the extreme sensitivity of their optoelectronic properties to environmental stimuli, engineering SWCNT materials is complex. The key ingredient is maintaining a relatively interaction-free local environment during the material synthesis. Toward this end, selection of the correct protective wrappings (i.e. surfactants, polymers, DNA, etc) and added materials (i.e. porphyrin, salts, acids, etc) to maintain or tune the tubes optoelectronic properties for a desire application is crucial. We will highlight some of our recent SWCNT mesomaterials and discuss the effects each of the matrixes has on SWCNT optoelectronic properties. We will introduce photoactive molecules and discuss the electronic interactions we observe with SWCNTs and how these various additives can be used to control the final material properties for targeted applications such as sensors and photovoltaics.

Block copolymers can be used as materials for generating mimics of biological membrane assemblies. Polymer membranes have the advantages of being robust, tunable by functionality and possess a larger degree of dynamic responsive behavior relative to their lipid counterparts. We report on the development of 2D- and 3D-membrane nanocomposites based upon block copolymer strategies, particularly toward the generation of responsive energetic materials. For example, block copolymers can be used as surfactants for the solubilization of nanomaterials such as carbon fullerenes and nanotubes. In such a manner, block copolymers can act as surfactants that allow for solubilization of hydrophobic materials and serve as a dynamic architecture for housing photonic cofactors that can perform processes such as energy and electron transfer in a responsive manner dependent upon environmentally-stimulated polymer organization. Further, amphiphilic polymers have the potential of serving as surfactants for biological, amphiphilic protein complexes, many of which are energetic in nature. We have studied the biophysical properties of such nanocomposite architectures such as environmentally controlled energy and electron transfer processes and worked toward developing three-dimensional mesocomposite materials consisting of long-range organization and induced functional properties.

Cooperative binary ionic (CBI) solids comprise a versatile new class of opto-electronic and catalytic materials consisting of ionically self-assembled pairs of organic anions and cations. Herein, we report CBI nanocomposites formed by growing nanoparticles of one type of porphyrin CBI solid onto a second porphyrin CBI substructure with complementary functionality.

Varying the solution growth conditions of cooperative binary ionic solids composed of anionic and cationic metalloporphyrins produces a series of families of self-assembled structures that efficiently and durably photosensitize the evolution of hydrogen.

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