Superior Surface Area Research Articles

Efficient production of activated carbons from PET for organic supercapacitor applications: A single-step approach

This study introduces a novel approach for synthesizing supercapacitor electrode materials using polyethylene terephthalate (PET), a plastic facing recycling challenges. Unlike conventional methods that involve separate carbonization and activation steps, we employ a single-step method. In this process, activated carbons are synthesized using potassium hydroxide (KOH) as an activating agent. Remarkably, the yield via the single-step method (S_PACXs) exceeds that of the two-step method (T_PACYs) by at least 1.7 times. During the single-step process, KOH forms a layer on the PET surface before activation, which leads to increased yields, higher specific surface areas, and more developed mesopores. Furthermore, S_PACXs exhibit superior specific surface areas compared to commercial activated carbon. These enhanced properties significantly improve electrochemical performance, with S_PACXs demonstrating superior performance compared to T_PACYs. Ultimately, this study validates the efficiency of the single-step method in producing high-quality activated carbon from PET, saving time and energy, and outperforming the two-step method.

The role of the activation heating source on the carbon capture performance of two new adsorbents produced from household-mixed-plastic waste

This study reveals the impact of the activation with microwave and conventional heating sources on textural properties and CO2 uptake of a mixed plastic-based char. Two mixed plastic-based adsorbents, one activated using microwaves and the other using conventional heating, were produced at optimum activation conditions, and subsequently compared. The findings show that both heating sources produced microporous adsorbents, but activation heating sources influenced their physicochemical properties and CO2 uptake. The microwave-produced activated carbon (AC) displayed superior BET surface area, total, micro- and ultra-micropore volumes compared to the conventionally produced AC. The microwave-produced AC possessed CO2 adsorption capacities of 1.66 and 2.37 mmol/g under dynamic and equilibrium conditions, respectively, at 25 °C and 1 bar. These capacities represent an 8 and 30 % higher uptake, respectively, compared to the 1.53 and 1.66 mmol/g displayed by the conventionally prepared AC under the same adsorption conditions. Both samples displayed stable and excellent CO2 recyclability over 10 adsorption-desorption cycles, with desorption efficiencies ranging from 93.46 % to 96.72 % (microwave- and conventionally- produced ACs respectively). The Avrami model most accurately described the experimental CO2 adsorption data under dynamic conditions, while the Sip model gave the best fit for equilibrium conditions. These findings apply to both types of ACs at various temperatures, irrespective of the heating source. Overall microwave heating is more efficient than conventional heating, requiring 300°C lower temperature, 115 minutes shorter time, 0.79 kWh less energy, and less KOH. It improves CO2 uptake and reduces production costs by 80 %, offering a sustainable alternative for CO2 adsorbent production.

Fabrication of a graphene@Ni foam-supported silver nanoplates-PANI 3D architecture electrode for enzyme-free glucose sensing.

Reliable and cost-effective glucose sensors are in rising demand among diabetes patients. The combination of metals and conducting polymers creates a robust electrocatalyst for glucose oxidation, offering enzyme-free, high stability, and sensitivity with outstanding electrochemical results. Herein, graphene is grown on nickel foam by chemical vapor deposition to make a graphene@nickel foam scaffold (G@NF), on which silver nanoplates-polyaniline (Ag-PANI) 3D architecture is developed by sonication-assisted co-electrodeposition. The resulting binder-free 3D Ag-PANI/G@NF electrode was highly porous, as characterized by x-ray photoelectron spectroscopy, Field emission scanning electron microscope, x-ray diffractometer, FTIR, and Raman spectroscopy. The binder-free 3D Ag-PANI/G@NF electrode exhibits remarkable electrochemical efficiency with a superior electrochemical active surface area. The amperometric analysis provides excellent anti-interference performance, a low limit of deduction (0.1 nM), robust sensitivity (1.7 × 1013µA mM-1cm-2), and a good response time. Moreover, the Ag-PANI/G@NF enzyme-free sensor is utilized to observe glucose levels in human blood serums and exhibits excellent potential to become a reliable clinical glucose sensor.

Performance Enhancement of Self-Powered Electrochromic Device via a PEDOT:PSS Electrode Inherited with Intrinsic Roughness of Substrate.

The electrode optimization and rational design are of great significance for the performance enhancement of self-powered electrochromic devices (ECDs). It can be effectively enhanced by developing interfacial properties of electrodes, which can promote the internal ion transport within functional components consisting of an electrode, electrochromic layer, and electrolyte layer and thus obtain performance improvement of fabricated devices. This work aims to construct the electrode of poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT:PSS) on different substrates and promote interface performance of the prepared electrodes via inheriting the surface topography of substrates. Besides, the prepared PEDOT:PSS electrodes as a dual-function layer including the electrochromic and electrode layer are employed to assemble the ECDs. It is found that the intrinsic roughness of the paper substrate can facilitate the electrochemical performance of the prepared PEDOT:PSS electrode on it effectively, thereby showing a superior electrochemical surface area and diffusion coefficient as well as a lower charge-transfer resistance of 13.56 Ω. Similarly, for the prepared self-powered ECD on the paper substrate, it also indicates a high light absorption property (0.413), well-defined electrochromic contrast (33.09), fast switching (τc = 4.0 s, τb = 6.8 s), high coloration efficiency (92.275 cm2 C-1), high areal capacity (10.93 mAh m-2) at 0.01 mA cm-2, and lower equivalent series resistance (176.2 Ω) in comparison to parallel ECDs on the PET and glass substrate. Leveraging the intrinsic roughness of the substrate is able to enhance the electrochemical performance of electrodes, which can also provide a new strategy for the construction of high-performance self-powered ECDs.

Scalable fabrication of high surface area g-C3N4 nanotubes for efficient photocatalytic hydrogen production

In this research, we present a novel facile, scalable, and template-free technique of synthesizing graphitic carbon nitride (g-C3N4) nanotubes for generating hydrogen through photocatalysis. The hybrid technique involves a two-fold mixing of the precursor materials melamine (M) and cyanuric acid (CA), involving ball milling followed by solution mixing. By varying the M:CA molar ratios, different compositions of g-C3N4 nanotubes were fabricated. The study focused on examining the surface characteristics and the photocatalytic hydrogen evolution performance of these nanotubes. Nanotubes with high specific surface area of 206 m2 g−1 for M:CA molar ratio of 1:3 and 178 m2 g−1 for M:CA molar ratio of 1:5 were produced, with H2 evolution rates of 543 μmol h−1 g−1 and 740 μmol h−1 g−1 respectively, which were an increase of 4 and 5-fold, respectively, in comparison to the pristine sample. The enhanced efficiency of hydrogen production through photocatalysis by nanotubes, when contrasted with pristine material, can be ascribed to their high crystallinity, superior specific surface areas, decreased recombination rates of electron-hole pairs generated during light exposure, and improved dynamics of charge carriers. This hybrid technique provides a new pathway for cost-effective fabrication of g-C3N4 nanotubes with substantial surface areas and high yield photocatalysts on an industrial scale, without the use of templates and hydrothermal processes for efficient hydrogen generation.

Chromoionophoric molecular probe infused bimodal porous polymer rostrum as solid-state ocular sensor for the selective and expeditious optical sensing of ultra-trace toxic mercury ions

This study presents a distinctive solid-state naked-eye colorimetric sensing approach by encapsulating a chromoionophoric probe onto a hybrid macro-/meso-pore polymer scaffold for fast and selective sensing of ultra-trace Hg(II). The customized structural/surface properties of the poly(VPy-co-TM) monolith are attained by specific proportions of 2-vinylpyridine (VPy), trimethylolpropane trimethacrylate (TM), and pore-tuning solvents. The interconnected porous network of poly(VPy-co-TM), inherent superior surface area and porosity, is captivating for the homogeneous/voluminous incorporation of probe molecules, i.e., 7-((4-methoxyphenyl)diazenyl)quinoline-8-ol (MPDQ), for the target-specific colorimetric detection. The structural morphology, surface topography, and phase characteristics of the bare poly(VPy-co-TM) monolith and MPDQ@poly(VPy-co-TM) sensor are examined using HR-TEM-SAED (High-Resolution Transmission Electron Microscopy - Selected Area Electron Diffraction), FE-SEM-EDAX (Field Emission Scanning Electron Microscopy - Energy Dispersive X-ray Spectroscopy), XPS (X-ray Photoelectron Spectroscopy), p-XRD (Powder X-Ray Diffraction), FT-IR (Fourier Transform Infrared Spectroscopy), UV-Vis-DRS (Ultraviolet-Visible Diffuse Reflectance Spectroscopy), and BET/BJH (Brunauer-Emmett-Teller / Barrett-Joyner-Halenda) analysis. The distinctive properties of the sensor reveal a constrained geometrical orientation of the MPDQ probe onto the long-range continuous monolithic network of meso-/-macropore template, enabling selective interaction with Hg(II) with peculiar color transfiguration from pale yellow to deep brown. The sensor demonstrates a linear spectral-color alliance in the 0–200 ppb concentration range for Hg(II), with quantification and detection limits of 0.63 and 0.19 ppb. The sensor efficacy is verified using certified contaminated water and tobacco samples, with excellent reusability, reliability, and reproducibility of ≥ 99.23 % (RSD ≤1.89 %) and ≥ 99.19 % (RSD ≤1.94 %) of Hg(II), respectively.

Causal association between brain structure and obstructive sleep apnea: A mendelian randomization study

ObjectivePrevious studies have reported contradictory findings regarding the relationship between obstructive sleep apnea (OSA) and abnormal brain morphology. Furthermore, the causal relationship between OSA and brain morphology has not been clearly established. The aim of this study was to utilize Mendelian randomization (MR) analysis to investigate the impact of obstructive sleep apnea (OSA) on brain morphology and determine its potential causal relationship. MethodsFirstly, the inverse-variance weighted (IVW) method was employed to assess the causal effects of OSA on cortical surface area and brain structure volume. Additionally, two additional MR methods, namely weighted median and MR-Egger, were used to supplement the results from IVW. Subsequently, a reverse MR analysis was conducted to determine the direction of causality. Furthermore, sensitivity analyses were performed including Cochrane's Q test, MR-Egger intercept test, MR-PRESSO global test, and leave-one-out analysis. ResultsThe results of the study showed that OSA patients had a tendency towards decreased cortical surface area and hippocampal volume in the precuneus region compared to individuals without OSA, while the superior temporal cortical surface area showed an increase. The results from the weighted median and MR-Egger analyses were consistent with those from the IVW analysis. Sensitivity tests confirmed the reliability of the causal estimates. ConclusionsThis study provides preliminary evidence of an association between OSA and brain structure using large-scale genome-wide association data. The results demonstrate that OSA is associated with changes in brain structure. Therefore, individuals with OSA should be vigilant about the risks of related diseases due to alterations in brain tissue.

Modification of nickel foam with nickel phosphate catalyst layer via anodizing for boosting the electrocatalytic urea oxidation and hydrogen evolution reactions

Urea oxidation reaction (UOR) and hydrogen evolution reaction (HER) are the key processes for implementing urinated water electrolysis and hydrogen green production, respectively. This contribution investigates the modification of commercial nickel foam (NF) with a nickel phosphate (NiPO/NF) heterostructure layer via anodizing in phosphate solution at various potentials (5, 10 and 15 V) as a simple and efficient route to boost the urea-assisted water electrolysis and hydrogen production in alkaline medium. The morphology and composition physicochemical characterisation of the phosphate layer exhibit aggregates of crystalline nanoparticles with interstitial mesoporous and macroporous networks with a mole composition ratio of 9.42: 1.0: 8.14 for Ni: P: O respectively. The electrochemical measurements revealed the NiPO/NF anodized at 10 V exhibits a superior electroactive surface area of 255 cm2, a substantially higher urea oxidation current compared to pristine NF, achieving 20 and 500 mA/cm2 at 1.35 and 1.6 V vs. RHE respectively and retained 100 % of activity during the urea electrolysis for more than 3 h. The electrochemical impedance analysis confirmed the alkaline urea oxidation reaction proceeded via indirect (EC) and direct mechanism and the CO2 intermediates adsorption–desorption became the predominant reaction at more positive potential. The NiPO/NF anode employed in an H-shape can deliver up to ±400 mA/cm2 for UOR/HER at a bias potential of 1.85 V and 8-fold (2.0 mmol/min) much higher hydrogen production rate compared to the pristine NF anode (0.25 mmol/min). Combining commercial nickel foam modification via anodizing and alkaline urea electrolysis at ambient conditions offers a unique and innovative solution for both large-scale hydrogen green production as well as remedy of the urinated wastewater for a more sustainable future.

Causal effects of hypertensive disorders of pregnancy on structural changes in specific brain regions: a Mendelian randomization study.

This study utilized Mendelian randomization to explore the impact of hypertensive disorders of pregnancy and their subtypes on brain structures, using genome-wide association study data from the FinnGen consortium for hypertensive disorders of pregnancy exposure and brain structure data from the ENIGMA consortium as outcomes. The inverse-variance weighted method, along with Cochran's Q test, Mendelian randomization-Egger regression, Mendelian randomization-PRESSO global test, and the leave-one-out approach, were applied to infer causality and assess heterogeneity and pleiotropy. Findings indicate hypertensive disorders of pregnancy are associated with structural brain alterations, including reduced cortical thickness in areas like the insula, isthmus cingulate gyrus, superior temporal gyrus, temporal pole, and transverse temporal gyrus, and an increased surface area in the superior frontal gyrus. Specific associations were found for hypertensive disorders of pregnancy subtypes: chronic hypertension with superimposed preeclampsia increased cortical thickness in the supramarginal gyrus; preeclampsia/eclampsia led to thinner cortex in the lingual gyrus and larger hippocampal volume and superior parietal lobule surface area. Chronic hypertension was associated with reduced cortical thickness in the caudal and rostral anterior cingulate and increased surface area of the cuneus and thickness of the pars orbitalis cortex. Gestational hypertension showed no significant brain region changes. These insights clarify hypertensive disorders of pregnancies' neurological and cognitive effects by identifying affected brain regions.

Advances in Carbon Xerogels: Structural Optimization for Enhanced EDLC Performance.

This review explores the recent progress on carbon xerogels (CXs) and highlights their development and use as efficient electrodes in organic electric double-layer capacitors (EDLCs). In addition, this work examines how the adjustment of synthesis parameters, such as pH, polymerization duration, and the reactant-to-catalyst ratio, crucially affects the structure and electrochemical properties of xerogels. The adaptability of xerogels in terms of modification of their porosity and structure plays a vital role in the improvement of EDLC applications as it directly influences the interaction between electrolyte ions and the electrode surface, which is a key factor in determining EDLC performance. The review further discusses the substantial effects of chemical activation with KOH on the improvement of the porous structure and specific surface area, which leads to notable electrochemical enhancements. This structural control facilitates improvement in ion transport and storage, which are essential for efficient EDLC charge-discharge (C-D) cycles. Compared with commercial activated carbons for EDLC electrodes, CXs attract interest for their superior surface area, lower electrical resistance, and stable performance across diverse C-D rates, which underscore their promising potential in EDLC applications. This in-depth review not only summarizes the advancements in CX research but also highlights their potential to expand and improve EDLC applications and demonstrate the critical role of their tunable porosity and structure in the evolution of next-generation energy storage systems.

Fabrication and characterization of UTSA-16 metal-organic frameworks with excellent adsorption performances on CO2

Abstract In this research, two distinct UTSA-16 metal-organic frameworks were synthesized using the solvothermal method. These frameworks were characterized by XRD, FTIR, SEM, BET, and TGA. Both materials had complete structures, regular morphologies, and superior specific surface areas. At 25°C and 1 bar, UTSA-16 (Co) demonstrated a maximum CO2 adsorption ability of 183 mg/g, while UTSA-16 (Zn) demonstrated a maximum CO2 adsorption ability of 161 mg/g. These findings present a development of MOFs with excellent adsorption performances on CO2 and simplified preparation processes.

Statistical modeling and multi-objective optimization of a flat tubular indirect evaporative cooler for enhanced performance

The flat tubular indirect evaporative cooler complements the conventional round tubular indirect evaporative cooler owing to its superior wetting surface area and enhanced heat transfer capacity. Given the multitude of influencing parameters, achieving a comprehensive analysis and optimization of the flat tubular indirect evaporative cooler demands a significant number of experimental tests or numerical simulations. Consequently, this study seeks to employ statistical techniques for constructing a precise and expeditious performance prediction model for the flat tubular indirect evaporative cooler. Nine pivotal parameters were selected to evaluate their impact on the cooling performance of the flat tubular indirect evaporative cooler. A numerical model was developed and verified experimentally. The response surface method was applied to establish polynomial regression equations for the cooling performance prediction of flat tubular indirect evaporative coolers. In addition, this work proposed a multi-objective optimization strategy for the proposed cooler. By innovatively using weighting factors to assign different weights to response values, multi-objective optimization with preferences was performed for the flat tubular indirect evaporative cooler with different demands to increase the applicability of the proposed cooler. The optimization results showed that when only the optimized wet-bulb efficiency was considered, the wet-bulb efficiency can reach up to 81.1%. When optimizing both the wet-bulb efficiency and the coefficient of performance simultaneously, the coefficient of performance can be up to 58.0, and the wet-bulb efficiency was 64.7%.

Advanced oxidation processes (AOPs): Navigating from MOS to COS and X-COS systems - Unraveling strategies, tackling challenges, and pioneering advances

This article presents a significant advancement in the field of photocatalysis through the synthesis of a MSO(Metal oxide semiconductor), COS (coupled oxide semiconductor) and X-COS(doped coupled oxide semiconductor) nanocomposite systems with diverse morphologies, including nanoflowers, nanorods, nanosheets, nanotubes and spherical shapes. In this particular study, we propose a hybrid methodology that amalgamates the coupling of CuO and ZnO oxides and the doping of various elements resulting in a comprehensive study of the relationship between morphology and photocatalysis. The degradation efficiency for various pollutants, including Methylene Blue (MB), Methyl Orange (MO), Green Malachite (GM), and Rhodamine B (RhB), was systematically investigated, employing distinct degradation mechanisms. Our study reveals that X-COS materials exhibit superior surface area, heightened porosity, and elevated specific capacitance, higher light absorption while minimizing energy and surface losses (VELF and SELF), accompanied by a well-suited morphology. These distinctive structural features of X-COS contribute to its enhanced photocatalytic efficiency when compared to MOS and COS systems. Our research not only consolidates the fundamental principles governing the photocatalytic properties of materials but also unveils critical strategies for fabricating highly efficient catalysts. In conclusion, this work significantly contributes to the evolving landscape of photocatalysis, offering a nuanced understanding of the synergistic relationship between morphology and catalytic efficiency. The findings not only broaden the scope of fundamental principles but also pave the way for the development of highly effective catalytic materials with diverse morphologies for environmental remediation applications.

Bimetallic Copper-Cerium-Based Metal-Organic Frameworks for Selective Carbon Dioxide Capture.

Metal-organic frameworks (MOFs) are highly regarded as valuable adsorbent materials in materials science, particularly in the field of CO2 capture. While numerous single-metal-based MOFs have demonstrated exceptional CO2 adsorption capabilities, recent advancements have explored the potential of bimetallic MOFs for enhanced performance. In this study, a CuCe-BTC MOF was synthesized through a straightforward hydrothermal method, and its improved properties, such as high surface area, smaller pore size, and larger pore volume, were compared with those of the bare Ce-BTC. The impact of the Cu/Ce ratio (1:4, 1:2, 1:1, and 3:2) was systematically investigated to understand how adding a second metal influences the CO2 adsorption performance of the Ce-BTC MOF. Various characterization techniques, including scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and N2 BET surface area analysis, were employed to assess the physical and chemical properties of the bare Ce-BTC and CuCe-BTC samples. Notably, CuCe-BTC-1:2 exhibited superior surface area (133 m2 g-1), small pore size (3.3 nm), and large pore volume (0.14 cm3 g-1) compared to the monometallic Ce-BTC. Furthermore, CuCe-BTC-1:2 demonstrated a superior CO2 adsorption capacity (0.74 mmol g-1), long-term stability, and good CO2/N2 selectivity. This research provides valuable insights into the design of metal-BTC frameworks and elucidates how introducing a second metal enhances the properties of the monometallic Ce-BTC-MOF, leading to improved CO2 capture performance.

Biomass waste lotus shell-based shape-stabilized phase change composites with improved thermal conductivity for thermal management

Lotus shells represent an underutilized renewable resource with desirable porous architecture for producing bio-based phase change composites (PCMs). This research endeavors to fabricate a series of shape-stable phase change composites (SSPCCs) based on n-docosane (ND) and waste lotus shells to enhance heat utilization, solar photothermal energy conversion, and promote environmental protection. Both carbonization and activation processes play a critical role in the formation of desired pore structures. The carbonized lotus shells (CLS) and activated lotus shells (ALS) exhibit superior specific surface areas, reaching 147.70 m2/g for CLS and 1652.35 m2/g for ALS. Notably, the composite of ND integrated with ALS (ND/ALS) exhibits satisfactory latent heat storage of 93.68 J/g, excellent leakage prevention, and exceptional thermal cycle stability. Subsequently, the ND/ALS displays a significantly enhanced thermal conductivity of 0.482 W/(m·K) with an appreciable increment of 189% compared to ND. Furthermore, the obtained SSPCCs present good chemical compatibility, satisfactory thermochemical stability, and outstanding thermal management capability. In conclusion, the novel waste lotus shell-derived SSPCCs exhibit extensive potential for thermal management, such as heat recovery, solar energy conversion, and temperature regulation. This research not only introduces a promising avenue for enhancing sustainable materials in energy storage and conversion but also pioneers an innovative recycling strategy for waste lotus shells, thereby contributing to both environmental sustainability and efficient resource utilization.

Fabricating NiCoFe2O4 decorated PANI nanostructures for high-performance electrochemical detection of 3-Nitro-L-tyrosine biomarkers for rapid diagnosis

A recent development in novel catalytic nanostructures offers numerous opportunities to perform the electrochemical operations towards sensing applications. The organic material PANI has been endorsed as a conducting polymer as it has controlled electrical properties and low density which will be beneficial over the metallic nanostructures. Herein, Nickel Cobalt Ferrite (NiCoFe2O4 (NCF)) nanostructures were anchored on the surface of PANI and engineered for electrochemical sensing applications. 3-nitro-L-tyrosine (3-NT) is an important compound for diagnosing oxidizing biomarkers that plays a vital role in therapy and diagnosing pathogenesis. Due to NCF/PANI’s conductivity, and superior surface area. It was probed for electrochemical sensing of 3-NT. The NCF/PANI displayed an excellent LOD, broad linear range, better sensitivity, selectivity, and stability. Furthermore, the proposed sensor exhibits sensitive 3-NT detection in biological samples with satisfactory recovery rates.

Sustainable and reusable probe-encapsulated porous poly(AMST-co-TRIM) monolithic sensor for the selective and ultra-sensitive detection of toxic cadmium(II) from industrial/environmental wastewater

This study focuses on a new type of fast responsive solid-state visual colorimetric sensor, custom engineered with dual-entwined porous polymer imbued with chromoionophoric 4-(sec-butyl)− 2-((5-mercapto-1,3,4-thiadiazol-2-yl)diazenyl)phenol (SMDP) probe for selective and ultra-sensitive colorimetric sensing of Cd(II). The polymer monolith, i.e., poly(aminostyrene-co-trimethylolpropanetrimethacrylate) denoted as poly(AMST-co-TRIM), is designed through a stoichiometric blending of monomer, crosslinker, and porogens leading to superior surface area, pore and adsorption properties for the voluminous incorporation of SMDP probe for target specific ion sensing. The porosity, surface and structural characteristics of the poly(AMST-co-TRIM)monolith and poly(AMST-co-TRIM)SMDP sensor are investigated using p-XRD, XPS, TG-DTA, FT-IR, BET/BJH, FE-SEM, HR-TEM, EDAX, and SAED techniques. The poly(AMST-co-TRIM)SMDP sensor reveals a frozen geometrical orientation of SMDP molecules to bind selectively with Cd(II), forming stable charge-transfer complexes by exhibiting transitional visible color shifts from light yellow to dark green (λmax 608 nm). The sensor imposes a linear response from 0–200 ppb, with quantification and detection limits of 0.95 and 0.28 ppb. The fabricated sensor material is cost-effective and versatile in its solid-state naked-eye sensing, with excellent reusability. The sensor performance has been verified using various environmentally contaminated water and commercial cigarette samples, with a recovery of ≥ 99.12% and an RSD of ≤ 1.95%, thus reflecting exceptional data reproducibility/reliability.

Exploring alkyl-diamine chain length effects on electrochemical behavior of AuNPs fabricated electrodes: Influence of linkers on the sensitive detection of hydrazine

In this electrochemical exploration, we scrutinized the influence of alkyl-diamine (AD) chain length as crucial linkers between glassy carbon electrodes (GCE) and citrate-capped gold nanoparticles (Cit-AuNPs), focusing on their conductive behavior and sensing proficiency, particularly in hydrazine detection. Meticulous examination of self-assembled monolayers (SAMs) formed by three distinct ADs, namely 1,6-hexanediamine (HDA), 1,8-octanediamine (ODA) and 1,10-decanediamine (DDA) unfolded over GC surfaces revealed a precise adherence to Langmuir adsorption kinetics during the SAM formation process. Utilizing cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), the electrochemical activity of the [Ru(NH₃)₆]³⁺/²⁺ redox pair at electrodes modified with ADs was investigated. The proposed mechanism involves a Michael-like nucleophilic addition process at the GC surface/diamine solution interface during the SAM formation. Analysis across various techniques underscored the compact nature of the DDA-formed SAM in comparison to HDA and ODA. Exploiting the free amine functional groups on the SAMs, the as-synthesized Cit-AuNPs were attached on the electrode surface and investigated comprehensively through CV, EIS, attenuated total reflection Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Remarkably, Cit-AuNPs attached DDA-SAM/GC electrode offered superior electro active surface area, establishing an advanced electrochemical platform for carcinogenic hydrazine determination. The DDA/Cit-AuNPs electrode demonstrated a linear determination range of 0.003–1 mM, limits of detection at 11 nM, and sensitivity of 1080 µA mM−1 cm−2. This study gives a complete picture of how AD chain lengths, SAM formation, Cit-AuNPs attachment, and electrocatalytic performance work together to make an advanced electrochemical sensing scaffold for environmental pollutants determination.

Multiplex signal amplification for ultrasensitive CRP assay via integrated electrochemical biosensor array using MOF-derived carbon material and aptamers

Accurate and precise detection of disease-associated proteins, such as C-reactive protein (CRP), remains a challenge in biosensor development. Herein, we present a novel approach－an integrated disposable aptasensor array－designed for precise, ultra-sensitive, and parallel detection of CRP in plasma samples. This integrated biosensing array platform enables multiplex parallel testing, ensuring the accuracy and reliability in sample analysis. The ultra-sensitivity of this biosensor is achieved through multiplex signal amplification. Leveraging the superior conductivity and extensive surface area of MOF-derived nanoporous carbon material (CMOF), the biosensor enhances recognition elements (aptamers) by catalyzing the horseradish peroxidase (HRP) label enzyme reaction to multiply the number of probe molecules. Optimized conditions yielded exceptional performance, exhibiting high accuracy (relative standard deviation, RSD≤10.0 %), a low detection limit (0.3 pg/mL, S/N = 3), ultra-sensitivity (0.16 μA/ng mL−1 mm−2), and a rapid response (seven parallel tests within 60 min). Importantly, this multi-unit integrated disposable aptasensor array accurately quantified CRP in human serum, demonstrating comparable results to commercial enzyme–linked immunosorbent assay (ELISA). This technology showcases promise for detecting various biomarkers using a unified approach, presenting an appealing strategy for early disease diagnosis and biological analysis.

Gelatin-coated mesoporous forsterite scaffold for bone tissue engineering

This study aims to develop a mesoporous forsterite spheres-based scaffold for bone tissue regeneration. To achieve this goal, mesoporous forsterite spheres were fabricated using alginate (gel-forming agent) and activated charcoal (porogen). The impact of carbon concentration (2, 5, 10, and 20 wt %) and sintering temperature (1100 and 1200 °C) on the structural properties of mesoporous forsterite spheres was investigated. Additionally, gelatin coatings were applied to modify these spheres. Forsterite microspheres with a particle size of 2.43 ± 0.22 mm were successfully produced, exhibiting varying pore sizes based on the sintering temperature and carbon content. Notably, mesoporous forsterite spheres synthesized using 5 wt% carbon and sintered at 1200 °C displayed uniform morphology, a minor average diameter (2.4 ± 0.3 mm(, and an average pore size of 2.7 ± 0.9 μm. These optimized forsterite spheres exhibited mesoporous structures with superior surface area (2.93 m2g-1) and pore volume (0.009–0.048 cm3g-1). Furthermore, the gelatin coating, with an average thickness of 160 μm, was effectively applied to the forsterite spheres. The gelatin coating reduced the surface area (1.40 m2g-1), pore volume (0.003 cm3g-1), and average pore diameter to 9.26 nm, maintaining the mesoporous structure. Both mesoporous forsterite spheres successfully induced bone-like apatite formation in vitro during a 21-day immersion in simulated body fluid. Moreover, while both forsterite-based spheres exhibited cytocompatibility with MG63 cells (cell viability >80 %), the gelatin coating significantly enhanced osteogenic differentiation (1.29 times). In conclusion, gelatin-coated mesoporous forsterite spheres exhibit promising potential as bioactive filling scaffolds for bone tissue regeneration.