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ACS Applied Materials & Interfaces Jan 2022We report an experimental and computational approach for the fabrication and characterization of a highly sensitive and responsive label-free biosensor that does not...
We report an experimental and computational approach for the fabrication and characterization of a highly sensitive and responsive label-free biosensor that does not require the presence of redox couples in electrolytes for sensitive electrochemical detection. The sensor is based on an aptamer-functionalized transparent electrode composed of nanoporous anodized alumina (NAA) grown on indium tin oxide (ITO)-covered glass. Electrochemical impedance changes in a thrombin binding aptamer (TBA)-functionalized NAA/ITO/glass electrode due to specific binding of α-thrombin are monitored for protein detection. The aptamer-functionalized electrode enables sensitive and specific thrombin protein detection with a detection limit of ∼10 pM and a high signal-to-noise ratio. The transient impedance of the alumina film-covered surface is computed using a computational electrochemical impedance spectroscopy (EIS) approach and compared to experimental observations to identify the dominant mechanisms underlying the sensor response. The computational and experimental results indicate that the sensing response is due to the modified ionic transport under the combined influence of steric hindrance and surface charge modification due to ligand/receptor binding between α-thrombin and the aptamer-covered alumina film. These results suggest that alumina film-covered electrodes utilize both steric and charge modulation for sensing, leading to tremendous improvement in the sensitivity and signal-to-noise ratio. The film configuration is amenable for miniaturization and can be readily incorporated into existing portable sensing systems.
Topics: Aluminum Oxide; Aptamers, Nucleotide; Biosensing Techniques; Dielectric Spectroscopy; Electric Impedance; Electrodes; Limit of Detection; Nanopores; Thrombin; Tin Compounds
PubMed: 34937345
DOI: 10.1021/acsami.1c17243 -
International Journal of Molecular... Aug 2021Efficient and safe nanopesticides play an important role in pest control due to enhancing target efficiency and reducing undesirable side effects, which has become a hot...
Efficient and safe nanopesticides play an important role in pest control due to enhancing target efficiency and reducing undesirable side effects, which has become a hot spot in pesticide formulation research. However, the preparation methods of nanopesticides are facing critical challenges including low productivity, uneven particle size and batch differences. Here, we successfully developed a novel, versatile and tunable strategy for preparing buprofezin nanoparticles with tunable size via anodic aluminum oxide (AAO) template-assisted method, which exhibited better reproducibility and homogeneity comparing with the traditional method. The storage stability of nanoparticles at different temperatures was evaluated, and the release properties were also determined to evaluate the performance of nanoparticles. Moreover, the present method is further demonstrated to be easily applicable for insoluble drugs and be extended for the study of the physicochemical properties of drug particles with different sizes.
Topics: Aluminum Oxide; Coated Materials, Biocompatible; Electrodes; Insecticides; Materials Testing; Metal Nanoparticles; Porosity; Surface Properties; Thiadiazines
PubMed: 34361113
DOI: 10.3390/ijms22158348 -
Macromolecular Rapid Communications Jan 2020Block copolymers have a wide range of functions in advanced electrochemistry because of their ability to self-assemble into ordered nanometer-sized structures, resulting... (Review)
Review
Block copolymers have a wide range of functions in advanced electrochemistry because of their ability to self-assemble into ordered nanometer-sized structures, resulting in their extensive usage as nanoporous templates that can be electrochemically manipulated. These highly ordered nanoporous templates are used as working electrodes for electrodeposition and electropolymerization to build nanoelectrode arrays and can serve as models to study the diffusion pathway of redox-active units with regard to chemical modification of pores. The block copolymer system allows different morphologies to be utilized, but the most exploited structures are standing cylinders of the minority block that are etched to expose highly aligned porous nanoelectrode array templates. This review starts with introducing alumina and track-etched membranes as pioneer porous templates transitioning to the production of block copolymer films as succeeding templates, with a particular focus on both poly(styrene)-block-poly(methylmethacrylate) (PS-b-PMMA) and poly(styrene)-block-poly(lactide) (PS-b-PLA). The aim is to give fundamental insights of electrochemistry where functionality extends beyond to applications in the nanoscience field of biosensors and plastic electronics.
Topics: Aluminum Oxide; Biosensing Techniques; Electrochemical Techniques; Methacrylates; Nanopores; Nanotechnology; Polymers; Polystyrenes
PubMed: 31774602
DOI: 10.1002/marc.201900485 -
Analytical and Bioanalytical Chemistry Jan 2021Hybrid material surfaces on microparticles are emerging as vehicles for many biomedical multiplexing applications. Functionalization of these hybrid surface...
Hybrid material surfaces on microparticles are emerging as vehicles for many biomedical multiplexing applications. Functionalization of these hybrid surface microparticles to biomolecules presents unique challenges related to optimization of surface chemistries including uniformity, repeatability, and sample sparring. Hybrid interfaces between microlevel surfaces and individual biomolecules will provide different microenvironments impacting the surface functionalization optimization and efficiency. Here, we propose and validate the first demonstration of streptavidin adsorption-based antibody functionalization on unmodified, hybrid surface microparticles for in vitro analysis. We test this analytical technique and fabricate hybrid surface microparticles with a polystyrene core and aluminum oxide semi-coating. Additionally, we optimize the streptavidin-biotin functionalization chemistry in both assay implementation and sample sparring via analytical mass balances for these microparticles and subsequently conjugate anti-human CD11b antibodies. Result confirmation and characterization occurs from ultraviolet protein absorbance and ImageJ processing of fluorescence microscopy images. Additionally, we design and implement the multi-sectional imaging (MSI) approach to support functionalization uniformity on the hybrid surface microparticles. Finally, as a proof-of-concept performance, we validate anti-CD11b antibodies functionalization by visualizing hybrid surface microparticles conjugate to human neutrophils isolated from blood samples collected from potentially septic patients. Our study introduces and defines a category of functionalization for hybrid surface microparticles with the intent of minuscule sample volumes, low cost, and low environmental impact to be used for many cellular or proteomic in vitro multiplexing applications in the future. Graphical abstract.
Topics: Adsorption; Aluminum Oxide; Biotin; CD11b Antigen; Humans; In Vitro Techniques; Microscopy, Fluorescence; Microspheres; Neutrophils; Particle Size; Polystyrenes; Streptavidin; Surface Properties
PubMed: 33156401
DOI: 10.1007/s00216-020-03026-4 -
The Journal of Prosthetic Dentistry Jul 2022Dental implants undergo various surface treatments. Studies that have characterized their surface and subsurface by using the same methods are scarce.
STATEMENT OF PROBLEM
Dental implants undergo various surface treatments. Studies that have characterized their surface and subsurface by using the same methods are scarce.
PURPOSE
The purpose of this study is to physically characterize the surface and subsurface of implant systems made of commercially pure (cp) titanium (Ti) grade (gr) 4 and Ti alloy gr 23 and to evaluate whether airborne-particle abrasion and acid etching is an appropriate surface treatment for Ti alloy gr 23.
MATERIAL AND METHODS
Implant groups (n=3) were as follows: TG4AO, cp Ti gr 4, treated with anodic oxidation (3.5×8 mm) (NobelReplace Conical; Nobel Biocare); TG23AE, Ti gr 23 (TiAlV ELI) airborne-particle abraded-and-etched (3.9×8 mm) (V3; MIS); and TG4AE, cp Ti gr 4, airborne-particle abraded and etched (3.3×8 mm) (BL; Institut Straumann AG). Surface roughness, surface topography, and elemental and surface composition were investigated with optical profilometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The presence and size of Ti hydride (TiH) needles were determined on metallographic sections. Depth profiling was obtained by time-of-flight secondary ion mass spectrometry (ToF-SIMS) to determine possible enrichment of an alloying element at the implant surface.
RESULTS
The mean arithmetic deviation roughness (S), of TG4AO was 0.80 μm. The S of TG4AO was 1.22 μm, and the S of TG4AO was 1.59 μm. The difference between the groups was significant (P<.001). TG23AE and TG4AE displayed a macrotexture and microtexture with pores; TG4AO showed a 3-to 12-μm canyon-like structure. The surface and subsurface compositions were as follows: for TG4AO, αTi and phosphorus-rich anatase; for TG23AE, α-Ti matrix with β-Ti grains; and for TG4AE, α-Ti and δ-TiH. TiH needles were found only on TG4AE; the Ti oxide layer of TG4AO was rough, 3-to 16-μm thick, and porous. The time-of-flight secondary ion mass spectrometry (ToF SIMS) concentration profile of TG23AE did not show enrichment of any alloying element.
CONCLUSIONS
The roughness, topography, and composition of the surfaces were different for all implants tested. Airborne-particle abrasion and subsequent etching was an appropriate treatment for Ti gr 23 alloy implants.
Topics: Alloys; Aluminum Oxide; Dental Implants; Dental Materials; Materials Testing; Microscopy, Electron, Scanning; Surface Properties; Titanium
PubMed: 33546854
DOI: 10.1016/j.prosdent.2020.11.015 -
Journal of the Mechanical Behavior of... Aug 2021This study evaluated the effect of distinct surface treatments on the fatigue behavior (biaxial flexural fatigue testing) and surface characteristics (topography and...
This study evaluated the effect of distinct surface treatments on the fatigue behavior (biaxial flexural fatigue testing) and surface characteristics (topography and roughness) of a 5% mol yttria partially stabilized zirconia ceramic (5Y-PSZ). Disc-shaped specimens of 5Y-PSZ (IPS e.max ZirCAD MT Multi) were manufactured (ISO 6872-2015) and allocated into six groups (n = 15) considering the following surface treatments: Ctrl - no-treatment; GLZ - low-fusing porcelain glaze application; SNF - 5 nm SiO nanofilm; AlOx - aluminum oxide particle air-abrasion; SiC - silica-coated aluminum oxide particles (silica-coating); and 7%Si - 7% silica-coated aluminum oxide particles (silica-coating). The biaxial flexural fatigue tests were performed by the step-stress method (20Hz for 10,000 cycles) with a step increment of 50N starting at 100N and proceeding until failure detection. The samples were tested with the treated surface facing down (tensile stress side). Topography, fractography, roughness, and phase content assessments of treated specimens were performed. GLZ group presented the highest fatigue behavior, while AlOx presented the lowest performance, and was only similar to SiC and 7%Si. Ctrl and SNF presented intermediary fatigue behavior, and were also similar to SiC and 7%Si. GLZ promoted a rougher surface, Ctrl and SNF had the lowest roughness, while the air-abrasion groups presented intermediary roughness. No m-phase content was detected (only t and c phases were detected). In conclusion, the application of a thin-layer of low-fusing porcelain glaze, the deposition of silica nanofilms and the air-abrasion with silica-coated alumina particles had no detrimental effect on the fatigue behavior of the 5Y-PSZ, while the air-abrasion with alumina particles damaged the fatigue outcomes.
Topics: Aluminum Oxide; Ceramics; Dental Stress Analysis; Materials Testing; Silicon Dioxide; Surface Properties; Yttrium; Zirconium
PubMed: 33957570
DOI: 10.1016/j.jmbbm.2021.104543 -
Waste Management & Research : the... Nov 2022Red mud (RM) is a solid waste generated during the process of alumina production. RM has already posed a serious environmental threat with the development of the alumina... (Review)
Review
Red mud (RM) is a solid waste generated during the process of alumina production. RM has already posed a serious environmental threat with the development of the alumina refining industry. The comprehensive utilization of RM has attracted much attention due to its large-scale generation and harmful nature. This paper introduces the characteristics and state of RM and summarizes the relevant research on the comprehensive utilization of RM. The results show that comprehensive utilization of RM is mainly focused on the preparation of building materials, the extraction of valuable metals, catalyst synthesis and environmental protection. Besides, the article discusses the existing problems while utilizing RM. Prospects and suggestions for different utilization methods of RM are proposed.
Topics: Aluminum Oxide; Construction Materials; Industrial Waste; Metals; Solid Waste
PubMed: 35875958
DOI: 10.1177/0734242X221107987 -
International Journal of Molecular... Jul 2022In this article, we describe the antimicrobial properties of a new composite based on anodic aluminium oxide (AAO) membranes containing propyl-copper-phosphonate units...
In this article, we describe the antimicrobial properties of a new composite based on anodic aluminium oxide (AAO) membranes containing propyl-copper-phosphonate units arranged at a predetermined density inside the AAO channels. The samples were prepared with four concentrations of copper ions and tested as antimicrobial drug on four different strains of (K12, R2, R3 and R4). For comparison, the same strains were tested with three types of antibiotics using the minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests. Moreover, DNA was isolated from the analysed bacteria which was additionally digested with formamidopyrimidine-DNA glycosylase (Fpg) protein from the group of repair glycosases. These enzymes are markers of modified oxidised bases in nucleic acids produced during oxidative stress in cells. Preliminary cellular studies, MIC and MBC tests and digestion with Fpg protein after modification of bacterial DNA suggest that these compounds may have greater potential as antibacterial agents than antibiotics such as ciprofloxacin, bleomycin and cloxacillin. The described composites are highly specific for the analysed model strains and may be used in the future as new substitutes for commonly used antibiotics in clinical and nosocomial infections in the progressing pandemic era. The results show much stronger antibacterial properties of the functionalised membranes on the action of bacterial membranes in comparison to the antibiotics in the Fpg digestion experiment. This is most likely due to the strong induction of oxidative stress in the cell through the breakdown of the analysed bacterial DNA. We have also observed that the intermolecular distances between the functional units play an important role for the antimicrobial properties of the used material. Hence, we utilised the idea of the 2D solvent to tailor them.
Topics: Aluminum Oxide; Anti-Bacterial Agents; Bacteria; Copper; DNA, Bacterial; DNA-Formamidopyrimidine Glycosylase; Escherichia coli; Escherichia coli Proteins
PubMed: 35955460
DOI: 10.3390/ijms23158327 -
Environmental Science & Technology Feb 2020Natural organic matter and humic substances (HS) in soils and sediments participate in numerous biogeochemical processes. Sorption to redox-inert aluminum oxide (AlO)...
Natural organic matter and humic substances (HS) in soils and sediments participate in numerous biogeochemical processes. Sorption to redox-inert aluminum oxide (AlO) was recently found to affect the redox properties of HS both in sorbed and dissolved state. With this study, we aim to decipher the molecular basis for these observations by applying Fourier transform ion cyclotron resonance mass spectrometry (FT-ICRMS) and mediated electrochemical analysis to Elliott soil, Pahokee peat, and Suwannee river humic acid (HA) samples before and after sorption to polar AlO and a nonpolar sorbent (DAX-8 resin). The FT-ICRMS data provided evidence of preferential sorption of specific HA fractions, primarily tannin-like compounds, to AlO. These oxygen-rich compounds bear a high density of redox-active functional groups, and their adsorption leads to a depletion of electron exchange capacity in dissolved HAs and enrichment of HAs adsorbed at AlO. Sorption of HAs to DAX-8 was less selective and caused only slight changes in electron exchange capacities of dissolved and sorbed HA fractions. By combining FT-ICRMS and electrochemical approaches, our findings suggest that a selective sorption of oxygen-rich compounds in HA fractions to mineral oxides is a decisive factor for the different redox properties of dissolved and sorbed HA fractions.
Topics: Adsorption; Aluminum Oxide; Electrons; Humic Substances; Soil; Tannins
PubMed: 31894976
DOI: 10.1021/acs.est.9b04733 -
Bioinspiration & Biomimetics Jun 2020The quest for new light-weight materials with superior mechanical properties is a goal of materials scientists and engineers worldwide. A promising route in this pursuit...
The quest for new light-weight materials with superior mechanical properties is a goal of materials scientists and engineers worldwide. A promising route in this pursuit is drawing inspiration from nature to design and develop materials with enhanced properties. By emulating the graded mineral content and hierarchical structure of fish scales of the Arapaima gigas from the nano to macro scales, we were able to develop bioinspired laminated composites with improved impact resistance. Activated by the addition of nano-particles of AlO and nano-layers of TiN to a thermoplastic fiber substrate, new energy dissipation mechanisms operating at the nanoscale enhanced the energy absorption and stiffness of the bioinspired material. Remarkably, the newly developed materials are easily transferred to the industry with minimum associated manufacturing costs.
Topics: Aluminum Oxide; Animal Scales; Animals; Biomimetic Materials; Fishes; Nanotechnology; Titanium
PubMed: 32348973
DOI: 10.1088/1748-3190/ab8e9a