Colloidal Method Research Articles

Hierarchical Porous Ceramics with Distinctive Microstructures by Emulsion-Based Direct Ink Writing.

Hierarchical porous materials are ubiquitous in nature and have inspired the fabrication of cellular structures for a multitude of applications. As an extrusion-based 3D printing technique, direct ink writing (DIW) allows for customizable design and accurate control of printed structures. Recently, its combination with colloidal processing methods used for bulk porous ceramics, such as emulsion templating, has further extended its capability of fabricating porous ceramics across multiple length scales. In light of the recent development, the ink formulation for emulsion-based DIW can be further explored, and there is still a need for a better understanding of the structure-property relationship. Herein, we introduce two types of gelling additives, i.e., poly(ethylenimine) (PEI) and Pluronic F-127, respectively, into particle-stabilized emulsions and fabricate hierarchical porous alumina lattices by DIW. We discover that the two gelling additives can lead to distinctive microstructures due to their different gelling mechanisms. Moreover, the 3D printed hierarchical porous ceramic lattices are found to exhibit a potential energy absorption property. The effects of ink formulations, including gelling additives and solid loading, on ink rheology, microstructure, and mechanical properties are investigated. The 3D printed hierarchical porous ceramic lattices exhibit a high average porosity of 73.7%-79.3% with an average compressive strength of 1.53-9.61 MPa and a specific energy absorption of 0.33-2.67 J/g. Featuring two distinctive microstructures with tunable structural features and mechanical properties, the 3D printed hierarchical porous ceramics in this study have potential in many applications, including lightweight structures, tissue engineering scaffolds, filtration, etc.

Analysis of 4 cases of children with false-positive results of novel coronavirus-specific antibody

BackgroundThis study attempts to explore the influencing factors and solutions of the colloidal gold method for novel coronavirus (2019-nCoV)-specific IgM/IgG antibody detection, summarize the clinical experience and perfect the examination process, improving the application value of antibody detection in COVID-19 diagnosis.MethodsA total of 13,329 peripheral whole blood/plasma/serum samples were obtained for COVID-19 screening from children who visited the Children's Hospital of the Capital Institute of Pediatrics outpatient clinic from April 22, 2020, to November 30, 2020. The colloidal gold method was adopted for 2019-nCoV-specific IgM/IgG antibody detection. The virus nucleic acid test results, clinical records, and serum protein fingerprint results of antibody-positive patients were collected.ResultsAll samples were examined using the colloidal gold method with two 2019-nCoV-specific IgM/IgG antibody detection kits. Four patients were tested single antibody-positive using both kits. The details were as follows: two cases of IgM ( +) and IgG (-) using plasma and serum separately, two cases of IgM (-) and IgG ( +) using serum and whole blood. The protein fingerprinting results and nucleic acid tests of 2019-nCoV antibodies were negative in the 4 cases. Considering the epidemiological history, clinical manifestations, and test results, these 4 children were ruled out for 2019-nCoV infection.ConclusionsWhen the colloidal gold method was used to detect 2019-nCoV-specific IgM/IgG antibodies, it was important to ascertain the test results as precisely as possible. Specimen type and patient history may interfere with the diagnosis.

Turning CO2 to CH4 and CO over CeO2 and MCF-17 supported Pt, Ru and Rh nanoclusters – Influence of nanostructure morphology, supporting materials and operating conditions

Efficient conversion of CO2 into CH4 and CO brings an important opportunity to get valuable feedstock for a variety of industrially important reactions as both CH4 and CO are widely used as starting materials for the synthesis of valuable fuels and chemicals. Herein, we synthesized sub-nanometer (<2nm) Platinum (Pt), Ruthenium (Ru) and Rhodium (Rh) nanoclusters (NCs) via colloidal method; successfully decorated over mesoporous CeO2 and high surface area (HSA) siliceous meso-cellular foam (MCF 17) and tested for high-pressure CO2 reduction at lower temperature range (220–340 °C). Pt and Ru NCs exhibited typical reverse water gas shift (RWGS) and methanation catalytic performance respectively with minimal influence of the nature of support however, Rh NCs showed drastic variations in the product selectivity which exhibited strong influence of the support over the product distribution. Furthermore, Ru NCs (with a relatively lower metal loading ∼ 1 wt%) were found to be highly selective to CH4 (∼99 %) and stable (upto 40 hr time on stream) with either CeO2/MCF 17 at 340 °C; also Ru NCs exhibited comparatively the highest CO2 conversion (∼93 % in case of Ru NCs/CeO2) among the supported metal NCs. HRTEM results showed that metal NCs were homogeneously dispersed with a controlled and uniform particle size (<2nm); no substantial agglomeration of Ru NCs were observed after reaction. Beside the stable dispersion of NCs, Near Ambient Pressure (NAP) in situ XPS of Ru/CeO2 showed that the dynamic Ce3+/Ce4+ ratio of CeO2 can attribute to the high activity and selectivity.

Flow‐Based Synthesis of Gold‐Coated Magnetic Nanoparticles for Magnetoplasmonic Sensing Applications

Gold-coated magnetic nanoparticles are key materials for the fast separation and ultrasensitive detection of analytes in magnetoplasmonic sensors. However, the synthesis of gold-coated magnetic nanoparticles typically requires small-scale, colloidal methods over hours or days and often results in incomplete shells with variable optical properties. A robust, rapid, and scalable synthesis method is still needed to reliably form a complete gold nanoshell around magnetic nanoparticles. Herein, a new methodology for the synthesis of gold-coated magnetic nanoparticles via a flow-based manufacturing system that can easily be scaled up is presented. The developed method first produces gold-seeded silica coated magnetic nanoparticles and then a complete, tunable gold shell with relatively uniform size and shape. The flow-based method can be performed in a total time of less than 2 min, enabling rapid and complete gold coating. The particles show both excellent magnetic and plasmonic properties, which facilitates application as biosensing agents in dark-field microscopy and surface-enhanced Raman scattering.

Facile synthesis and tailoring the structural and photoluminescence properties of ZnO nanoparticles via annealing in air atmosphere

Herein, bulk synthesis of high quality wurtzite structured zinc oxide (ZnO) nanoparticles (NPs) by a facile wet chemical colloidal method is reported along with a detailed investigation on the effect of air annealing (up to 800 °C) on their structure, morphology, composition, optical and photoluminescence (PL) properties and their co-relation, rarely reported in such a wide temperature range. The as-prepared ZnO samples consisted of low sized quasi-spherical NPs (~25 nm) which agglomerated to form random shaped bigger NPs (100–500 nm) after annealing at 800 °C. The Zn/O ratio (wt%) approached to theoretical value for the samples annealed at 800 °C. Structural characteristics like crystallite dimensions, lattice parameters, strain, dislocation density, oxygen vacancy etc. have been evaluated. Further, structural conformation and co-existence of initial strain-free and the strained phases in the high temperature (≥800 °C) annealed ZnO NPs have been discussed with possible mechanism, an aspect not addressed before. Band gap narrowing was also observed from ~3.23 eV for the as-synthesized ZnO NPs to ~2.64 eV after annealing at 800 °C, which has been attributed to the decrease in the dislocation density, increase in the oxygen vacancies as well as the increase of dimensions and hence the number of grain boundaries of the ZnO NPs with annealing temperature. Significantly enhanced PL emission in the visible range was achieved by virtue of tailoring the structural and optical properties via high temperature annealing in the air atmosphere. Emission mechanism and their relation with different defects such as oxygen (VO), and zinc (VZn) vacancies, oxygen (Oi) and zinc (Zni) interstitials, etc. of the ZnO NPs is presented as function of annealing temperature in the air. Such an extensive study presents a better understanding and co-relation of the structure, morphology, composition, defects, optical and PL properties of the ZnO NPs prepared by a facile method with regards to annealing temperature and may find potential applications in optoelectronic devices.

Abstract LB167: Functional extracellular vesicle profiling with nanochips for cancer diagnosis and monitoring

Abstract Currently, most cancer cases are diagnosed with local or distant metastases that lead to ~90% of deaths from cancer. Widely used radiographic imaging detects large-size tumors and often fails to detect changes in tumor burden. Genomics centered on gene alterations faces challenges in capturing instant status of malignancy, such as invasive/metastatic phenotypes. In addition, tissue biopsy is highly invasive, costly, and often infeasible to repeat. Thus, novel non-invasive markers and tests that complement current paradigms for early detection and accurate tracking of tumor dynamics are urgently needed to improve clinical decision making and treatment. Extracellular vesicles (EVs), including exosomes, are emerging as a new class of liquid biopsy for cancer diagnosis and monitoring response to treatment. Growing evidence indicates important functions of EVs in tumor development, invasion, and metastasis, including matrix remodeling via transporting matrix metalloproteases (MMPs). However, their clinical relevance remains largely undetermined, partially owing to the challenges in EV analysis. We recently report a nanoengineered lab-on-a-chip system capable of integrative functional phenotyping of tumor-associated EVs. A generalized, high-resolution colloidal inkjet printing method was developed to afford robust and widely adaptable manufacturing of 3D nanopatterned microdevices. Enabled by this new nanofabrication technique, we built an integrated chip for multiparametric analysis of exosome circulation level, subtype, and enzymolytic activity (ExoCLUE). With various cancer cell lines and isogenic cell models created by CRISPR/Cas9 editing, we demonstrated that this nanochip affords ultrasensitive and specific analysis detection of the expression and proteolytic activity of MMP14 on EVs to measure in vitro cell invasiveness. With the experimental and spontaneous mouse models of breast cancer metastasis, we showed that the ExoCLUE chip with low sample input enables longitudinal monitoring of in vivo tumor growth and metastasis in single mice. Lastly, the ExoCLUE was assessed for clinical analysis of plasma from two independent training (n = 30) and validation (n = 70) cohorts of breast cancer patients. The proteolytic activity of MMP14+ EVs showed good performance to detect the patients (AUC = 0.986 for the validation set). Combined with a machine learning algorithm, the chip-based integrative functional EV analysis enabled classification of the control, pre-malignant ductal carcinoma in situ, invasive ductal carcinoma, and locally metastatic IDC patients with a high accuracy of 92.9%. Lastly, we have scaled up the ExoCLUE system to a high-throughput nanoarray platform for highly multiplexed functional EV profiling. Overall, our nanochip technology could provide a useful liquid biopsy tool to improve animal studies and clinical diagnosis of cancer. Citation Format: Yong Zeng, Shibo Chen, Yunjie Wen, Liang Xu. Functional extracellular vesicle profiling with nanochips for cancer diagnosis and monitoring [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB167.

Engineering gold-platinum core-shell nanoparticles by self-limitation in solution

Core-shell particles with thin noble metal shells represent an attractive material class with potential for various applications ranging from catalysis to biomedical and pharmaceutical applications to optical crystals. The synthesis of well-defined core-shell architectures remains, however, highly challenging. Here, we demonstrate that atomically-thin and homogeneous platinum shells can be grown via a colloidal synthesis method on a variety of gold nanostructures ranging from spherical nanoparticles to nanorods and nanocubes. The synthesis is based on the exchange of low binding citrate ligands on gold, the reduction of platinum and the subsequent kinetically hindered growth by carbon monoxide as strong binding ligand. The prerequisites for homogeneous growth are low core-binding ligands with moderate fast ligand exchange in solution, a mild reducing agent to mitigate homonucleation and a strong affinity of a second ligand system that can bind to the shell’s surface. The simplicity of the described synthetic route can potentially be adapted to various other material libraries to obtain atomically smooth core-shell systems.

A portable toolbox based on time-resolved fluoroimmunoassay and immunomagnetic separation for Cronobacter sakazakii on-site detection in dairy

A portable toolbox based on time-resolved fluoroimmunoassay and immunomagnetic separation was designed for on-site detection of Cronobacter sakazakii in dairy without advanced facilities. In this study, C. sakazakii was recognised and captured in milk by immunomagnetic beads, and europium chelated nanoparticles were used as signal probes in fluoroimmunoassays for quantitative analysis. Under optimal conditions, the capture efficiency of the immunomagnetic beads ranged from 77.76% to 98.26%. The time-resolved fluorescence intensity ratio was used to quantify C. sakazakii (y = 0.2615x – 0.1639, R2 = 0.9925) in the range of 102 to 107 cfu mL−1, and the limit of detection was as low as 73 cfu mL−1. The assay offered higher sensitivity for a total of 273 actual samples compared with the colloidal gold method. Our method can be completed within 2 h and may be a good model for on-site quantitation of food-borne pathogens with simplicity, rapidity, and cost-effectiveness.

Application of Foam Glass-Ceramic Composite Thermal Insulation Material in Traditional Buildings

In order to solve the application of thermal insulation materials in traditional buildings, a foam glass-ceramic composite thermal insulation material was proposed for the application of traditional buildings. First, the preparation of the hydrated glass matrix was completed by using the colloidal chemical method with sodium water glass, boric acid, calcium bentonite, and fly ash as the main raw materials. Second, using the introduction of crystalline mineral powder fly ash and secondary heat treatment, a low-temperature foam glass-ceramic composite material with lightweight, high strength, good water resistance, and low cost is prepared. Finally, the process parameters such as dehydroxylation heat treatment temperature and holding time involved in the preparation process were explored and optimized. It is proved that the external content of fly ash is 20 wt.% and above, and the external content of boric acid is 1-2 wt.%. The mixed sol has a bulk density of 192–256 kg/m2, a compressive strength of 0.44–0.63 MPa, a weight loss rate of 5.1–7.8 wt%, and a softening coefficient of 0.85–0.95, and thermal conductivity is 0.056–0.064 W/(m·K).

Pt-Modified Interfacial Engineering for Enhanced Photocatalytic Performance of 3D Ordered Macroporous TiO2

Narrowing the band gap and increasing the photodegradation efficiency of TiO2-based photocatalysts are very important for their wide application in environment-related fields such as photocatalytic degradation of toxic pollutants in wastewater. Herein, a three-dimensionally ordered macroporous Pt-loaded TiO2 photocatalyst (3DOM Pt/TiO2) has been successfully synthesized using a facile colloidal crystal-template method. The resultant composite combines several morphological/structural advantages, including uniform 3D ordered macroporous skeletons, high crystallinity, large porosity and an internal electric field formed at Pt/TiO2 interfaces. These unique features enable the 3DOM Pt/TiO2 to possess a large surface for photocatalytic reactions and fast diffusion for mass transfer of reactants as well as efficient suppression of recombination for photogenerated electron-hole pairs in TiO2. Thus, the 3DOM Pt/TiO2 exhibits significantly enhanced photocatalytic activity. Typically, 88% of RhB can be degraded over the 3DOM Pt/TiO2 photocatalyst under visible light irradiation (λ ≥ 420 nm) within 100 min, much higher than that of the commercial TiO2 nanoparticles (only 37%). The underlying mechanism for the enhanced photocatalytic activity of 3DOM Pt/TiO2 has been further analyzed based on energy band theory and ascribed to the formation of Schottky-type Pt/TiO2 junctions. The proposed method herein can provide new references for further improving the photocatalytic efficiency of other photocatalysts via rational structural/morphological engineering.

Synthesis of VS2/NiS Nanocomposites by In Situ Growing NiS Clusters on VS2 Ultrathin Nanoplates for High Performance Supercapacitors

AbstractNovel transition metal sulfide composite VS2/NiS nanomaterials are synthesized through a two‐step route, where VS2 was synthesized by colloidal chemical method, and NiS was in situ grown between the ultrathin and defective VS2 through a hydrothermal method. The composites showed VS2 nanoplates wrapped with a NiS clusters structure. Under the 1 : 7 optimal composite ratio, the VS2/NiS electrode exhibits a specific capacitance of 2416.5 F/g at 1 A/g, the specific capacitance stays at 930.2 F/g when the current density increases to 20 A/g. The asymmetric supercapacitor assembled with VS2/NiS‐1 : 7 and activated carbon electrodes also exhibits an ultrahigh energy density of 69.58 Wh/kg at a power density of 874.9 W/kg and showed good cycling performance with 74.9 % capacitance retention after 3000 cycles. This work not only demonstrates the excellent performance of the VS2/NiS composites in supercapacitors, but also provided a new compound strategy for transition metal sulfides.

Three-dimensional ordered structure for highly reversible neutral zinc-air battery

In view of the low utilization rate of zinc in secondary zinc-air batteries, 3DOM (three-dimensionally ordered macroporous) Ni was constructed on the steel mesh by colloidal crystal template-electrodeposition method, which significantly improved the interface area and optimized the electric field distribution in the electrodeposition process. Meanwhile, the ZIF-8 derivative is uniformly coated on the surface of 3DOM nickel to inhibit the hydrogen evolution reaction in the electrodeposition process of zinc, improving the affinity of electrode surface to zinc, and realizing the uniform electrodeposition of zinc. Finally, a highly reversible negative electrode material for neutral zinc-air battery was obtained, and 200 cycles were realized at a depth of discharge (DOD) of 41.7%.

Higher resolution protein band visualisation via improvement of colloidal CBB-G staining by gel fixation

BackgroundGel staining is a crucial step that allows the visualisation of proteins separated through SDS-PAGE. Colloidal Coomassie Brilliant Blue-G (CBB-G) staining is among the commonly used visualisation methods due to several factors such as compatibility with mass spectrometry (MS) analysis, sensitivity, reproducibility, and simplicity of the staining process. However, the standard colloidal CBB-G staining has a drawback: the resolution of protein bands is compromised because of diffusion of proteins during the washing step.ResultsA modification to an established colloidal CBB-G staining method, which greatly increases the resolution of protein bands, is described. The addition of a fixation step, which prevents the diffusion of proteins during the washing step, is shown to increase protein band resolution.ConclusionThe fixation step is fast, flexible, and also retains all the advantages of the standard colloidal CBB-G staining methods. As there are no drawbacks, incorporating this fixation step into the standard colloidal CBB-G staining is an easy way to improve protein visualisation in SDS-PAGE.Graphical

Colloidal Processing of Complex-Shaped ZrB2-Based Ultra-High-Temperature Ceramics: Progress and Prospects.

Ultra-high-temperature ceramics (UHTCs), such as ZrB2-based ceramics, are the most promising candidates for ultra-high-temperature applications. Due to their strong covalent bonding and low self-diffusion, ZrB2-based UHTCs are always hot-pressed at temperatures above 1800 °C. However, the hot-pressing technique typically produces disks or cylindrical objects limiting to relatively simple geometrical and moderate sizes. Fabrication of complex-shaped ZrB2-based UHTC components requires colloidal techniques. This study reviews the suspension dispersion and colloidal processing of ZrB2-based UHTCs. The most important issues during the colloidal processing of ZrB2-based UHTCs are summarized, and an evaluation of colloidal processing methods of the ZrB2-based UHTCs is provided. Gel-casting, a net or near-net colloidal processing technique, is believed to exhibit a great potential for the large-scale industrialization of ZrB2-based UHTCs. In addition, additive manufacturing, also known as 3D printing, which has been drawing great attention recently, has a great potential in the manufacturing of ZrB2-based UHTC components in the future.

Highly Sensitive Carbon Monoxide Sensor Element with Wide-Range Humidity Resistance by Loading Pd Nanoparticles on SnO2 Surface

To develop a highly sensitive carbon monoxide (CO) sensor with a wide range of humidity resistance, we focused on the Pd loading method on SnO2 nanoparticles and the thickness of the sensing layer. The Pd nanoparticles were loaded on the SnO2 surface using the surface immobilization method (SI-Pd/SnO2) and the colloidal protection method (CP-Pd/SnO2). The XPS analysis indicated that the Pd nanoparticles were a composite of PdO and Pd, regardless of the loading method. According to the evaluation of the electrical properties at 350 °C, the CO response in a humid atmosphere and the resistance toward humidity change using CP-Pd/SnO2 were higher than those using SI-Pd/SnO2, even though the Pd loading amount of SI-Pd/SnO2 was slightly larger than that of CP-Pd/SnO2. In addition, Pd/SnO2 prepared via the CP method with a thinner sensing layer showed a higher sensor response and greater stability to humidity changes at 300 °C, even though the humidity change influenced the CO response at 250 and 350 °C. Thus, the overall design of the surface Pd, including size, dispersity, and oxidation state, and the sensor fabrication, that is, the thickness of the sensing layer, offer a high-performance semiconductor-type CO gas sensor with a wide range of humidity resistance.

Three-dimensionally ordered macroporous Ce-W-Nb oxide catalysts for selective catalytic reduction of NO with NH3

• Ce-W catalyst is optimized by combining Nb-modification and structural manipulation. • 3DOM structure provides abundant diffusion channels for catalytic reactions. • 3DOM structure ensures the high dispersion of active components. • Synergistic effect among the species of Ce, Nb and W promotes the increase of O α . • Active NH 3 and NO x species are increased over 3DOM Ce-W-Nb catalysts. A string of 3DOM Ce-W-Nb ternary catalysts for NH 3 -SCR were prepared by a colloidal template method. The 3DOM Ce-W-Nb 0.15 catalyst had the best SCR activity and yielded more than 90% NO conversion at 275 ∼ 450 °C in the high GHSV of 120,000 h −1 . In addition, it exhibited good tolerance to H 2 O and SO 2 . The addition of Nb increased the number of active sites and made them dispersed more evenly, optimized the pore structure to a certain extent, and increased the specific surface area. The interaction among Ce, W, and Nb species promoted the increase of chemisorbed oxygen and enhanced the redox properties, thus contributing to the satisfactory SCR activity at low temperatures. In addition, the synergistic effect between Nb and W provided sufficient Lewis acid sites for the 3DOM Ce-W-Nb x catalyst, which was conducive to the good SCR performance at high temperatures. The NH 3 -SCR reaction on 3DOM Ce-W-Nb x catalysts followed both Eley-Rideal and Langmuir-Hinshelwood mechanisms. The doping of Nb was beneficial to boost the adsorption of NH 3 and improved the reactivities of NH 3 adsorbed species while facilitating the generation of active NO x species. These accelerated the reaction rate and optimized the reaction path.

Artificial nanomotors: Fabrication, locomotion characterization, motion manipulation, and biomedical applications

AbstractArtificial nanomotors are nanoscale machines capable of converting surrounding other energy into mechanical motion and thus entering the tissues and cells of organisms. They hold great potential to revolutionize the diagnosis and treatment of diseases by actively targeting the lesion location, though there are many new challenges that arise with decreasing the size to nanoscale. This review summarizes and comments on the state‐of‐the‐art artificial nanomotors with advantages and limitations. It starts with the fabrication methods, including common physical vapor deposition and colloidal chemistry methods, followed by the locomotion characterization and motion manipulation. Then, the in vitro and in vivo biomedical applications are introduced in detail. The challenges and future prospects are discussed at the end.

Evaluation of Mechanical and Electrical Performance of Aging Resistance ZTA Composites Reinforced with Graphene Oxide Consolidated by SPS.

This paper presents a study of Al2O3–ZrO2 (ZTA) nanocomposites with different contents of reduced graphene oxide (rGO). The influence of the rGO content on the physico-mechanical properties of the oxide composite was revealed. Graphene oxide was obtained using a modified Hummers method. Well-dispersed ZTA-GO nanopowders were produced using the colloidal processing method. Using spark plasma sintering technology (SPS), theoretically dense composites were obtained, which also reduced GO during SPS. The microstructure, phase composition, and physico-mechanical properties of the sintered composites were studied. The sintered ZTA composite with an in situ reduced graphene content of 0.28 wt.% after the characterization showed improved mechanical properties: bending strength was 876 ± 43 MPa, fracture toughness—6.8 ± 0.3 MPa·m1/2 and hardness—17.6 ± 0.3 GPa. Microstructure studies showed a uniform zirconia distribution in the ZTA ceramics. The study of the electrical conductivity of reduced graphene oxide-containing composites showed electrical conductivity above the percolation threshold with a small content of graphene oxide (0.28 wt.%). This electrical conductivity makes it possible to produce sintered ceramics by electrical discharge machining (EDM), which significantly reduces the cost of manufacturing complex-shaped products. Besides improved mechanical properties and EDM machinability, 0.28 wt.% rGO composites demonstrated high resistance to hydrothermal degradation.

A molecularly imprinted photonic polymer based on an inverse opal structure for sensing D-dimer at the point-of-care

Accurate and timely diagnosis of venous thromboembolism (VTE) is crucial to prevent related morbidity and mortality. This work reports a label-free sensor for D-dimer, a biomarker of VTE. The sensor is based on the synergy between the colloidal crystal templating method and the molecular imprinting technique. The design of the photonic molecularly imprinted polymer (PMIP) is focused on the preparation of an inverse opal structure, resulting from silica infiltration in a poly(methyl methacrylate) photonic crystal template, followed by a calcination stage that removes the sacrificial colloidal crystal. The molecularly imprinted polymer in the inverse opal structure is then synthesized in the presence of the template molecule, the peptide D-dimer. After D-Dimer removal, the PMIP consists in a three-dimensional highly ordered structure, where nanocavities complementary to the D-dimer in shape and binding features are distributed. The PMIP showed a linear response to D-dimer in synthetic urine, exhibiting a decrease in the reflectance intensity with increasing D-dimer concentrations, ranging from 22.5 ng mL−1 to 1450.0 ng mL−1. The PMIP material demonstrated a limit of detection of 15.5 ng mL−1 and was selective for D-dimer in the presence of fibrinopeptide B, another prospective VTE biomarker in urine. Moreover, the sensor was reusable up to five times without losing its recognition ability. Overall, a novel PMIP material is described for successful recognition of D-Dimer. Considering the clinical relevance of D-dimer detection, the sensor is envisioned as a promising low-cost test for urinalysis.

Colloidal synthesis of flower-like Zn doped Ni(OH)2@CNTs at room-temperature for hybrid supercapacitor with high rate capability and energy density

Transition metal oxides and hydroxides are typically applied as electrode materials for supercapacitors, but it is often difficult to achieve both their high power density and energy density simultaneously. Herein, electrodes of flower-like Zn doped Ni(OH)2 combined with carbon nanotubes (i.e., Zn doped Ni(OH)2@CNTs) were in-situ synthesized using a colloidal synthesis method at room-temperature, assisted by cetyltrimethyl ammonium bromide (CTAB) and NaBH4. This electrode exhibits an excellent electrochemical performance, achieving a high specific capacity of 750.5 C g-1 at 0.5 A g-1 and maintaining 72.9% of its initial value when the current density is increased from 1 A g-1 to 10 A g-1. A hybrid supercapacitor (HSC) assembled using the Zn doped Ni(OH)2@CNTs as the positive electrode and an active carbon as the negative electrode exhibits a capacity of 201.7 C g−1 at 1 A g-1 and an energy density of 51.3 Wh kg-1 at a power density of 409.6 W kg-1. After running for 50,000 cycles at a current density of 6 A g-1, the capacity of the HSC becomes 115.8% of its initial value. Moreover, this HSC maintains a high energy density of 29.33 Wh kg-1 at a high power density of 16.5 kW kg-1 after cycling for 50,000 times, which indicates its suitability for energy storage applications.