Biointerphases最新文献

The purpose of this Tutorial is to highlight the suitability of time-of-flight secondary ion mass spectrometry (ToF-SIMS) and OrbiTrap™ SIMS (Orbi-SIMS) in bone research by introducing fundamentals and best practices of bone analysis with these mass spectrometric imaging (MSI) techniques. The Tutorial includes sample preparation, determination of best-suited measurement settings, data acquisition, and data evaluation, as well as a brief overview of SIMS applications in bone research in the current literature. SIMS is a powerful analytical technique that allows simultaneous analysis and visualization of mineralized and nonmineralized bone tissue, bone marrow as well as implanted biomaterials, and interfaces between bone and implants. Compared to histological staining, which is the standard analytical procedure in bone research, SIMS provides chemical imaging of nonstained bone sections that offers insights beyond what is conventionally obtained. The Tutorial highlights the versatility of ToF- and Orbi-SIMS in addressing important questions in bone research. By illustrating the value of these MSI techniques, it demonstrates how they can contribute to advance progress in bone research.

The repair and homeostasis of peri-implant tissues depend on several factors such as the local presence of pathogenic bacteria and their products. Among other events, peri-implant tissue response is also related to the implant material used, which interferes with cells and extracellular matrix interactions, affecting the osseointegration process. In this study, the influence of zirconia (Zr) and titanium (Ti) substrates on the response of preosteoblasts (MC3T3) and murine macrophages (RAW 264.7) exposed to lipopolysaccharide (LPS, P. gingivalis) was evaluated. Zr and Ti disks were obtained and subjected to surface roughness standardization, which was analyzed by scanning electronic microscopy (SEM). The cells were subsequently cultured on Zr and Ti surfaces in AlphaMEM culture medium for 24 h, followed by LPS stimulus for 4 h. The production of reactive oxygen species (ROS) and gene expression of inflammatory markers were determined. SEM images showed that Ti disks exhibited higher surface roughness than that of Zr disks. Cells that seeded onto Ti and Zr had increased expression of inflammatory mediators and ROS production in the presence of LPS; however, such cell responses were more evident for Ti disks. These data indicate that contact of cells with Zr surfaces may lead to a lower inflammatory potential than Ti surfaces. Elucidation of the inflammatory response triggered by LPS for cells in contact with titanium and zirconia may contribute to the selection of materials for installation of osseointegrated implants.

Widespread contamination of the per- and polyfluoroalkyl substance (PFAS) in agricultural areas is largely attributed to the application of sewage sludge in which the PFAS can be concentrated. This creates a pathway for these contaminants to enter the food chain and, by extension, causes human health and economic concerns. One barrier to managing land with PFAS contamination is the variation in reported plant uptake levels across studies. A review of the literature suggests that the variation in plant uptake is influenced by a host of factors including the composition of PFAS chemicals, soil conditions, and plant physiology. Factors include (1) the chemical components of the PFAS such as the end group and chain length; (2) drivers of soil sorption such as the presence of soil organic matter (SOM), multivalent cation concentration, pH, soil type, and micropore volume; and (3) crop physiological features such as fine root area, percentage of mature roots, and leaf blade area. The wide range of driving factors highlights a need for research to elucidate these mechanisms through additional experiments as well as collect more data to support refined models capable of predicting PFAS uptake in a range of cropping systems. A conceptual framework presented here links drivers of plant PFAS uptake found in the literature to phytomanagement approaches such as modified agriculture or phytoremediation to provide decision support to land managers.

The present invention describes a novel flexible nanosensor for the electrochemical detection of uric acid (UA) present in urine. The synthesized graphite-boron nanocomposite with an average thickness of ∼32 nm was grown up on a flexible polyvinylidene fluoride film with an average thickness of ∼50 μm and it acts as a nonenzymatic sensor for UA. The developed flexible sensor showed a prominent reduction peak in cyclic voltammetry and amperometric response with the presence of different concentrations of aqueous UA solution. In the electrochemical study, the redox peak was generated near ∼-0.42 V with a detection limit of around ∼2.09 μM as the bottom level. The high robustness of the developed sensor originated from the polymeric film base and the rapid response time of ∼0.5 s for detecting UA present in human urine. The interference property of the sensor was confirmed in the presence of bilirubin and creatinine as an eventual reference toward selectivity. The phase and morphology of the sensor surface were extensively observed before and after sensing to comprehend the electrochemical interaction between the sensor and target molecules. The generated quantitative results of the integrated system were verified by testing known and unknown concentrations of UA solutions.

This article provides a comprehensive theoretical background of electronic sum frequency generation (ESFG), a second-order nonlinear spectroscopy technique. ESFG is utilized to investigate both exposed and buried interfaces, which are challenging to study using conventional spectroscopic methods. By overlapping two incident beams at the interface, ESFG generates a beam at the sum of their frequencies, allowing for the extraction of valuable interfacial molecular information such as molecular orientation and density of states present at interfaces. The unique surface selectivity of ESFG arises from the absence of inversion symmetry at the interfaces. However, detecting weak signals from interfaces requires the ultrafast lasers to generate a sufficiently strong signal. By understanding the theoretical foundations of ESFG presented in this article, readers can gain a solid grasp of the basics of ESFG spectroscopy.

Horseradish peroxidase (HRP) is a hemoglobin composed of a single peptide chain that catalyzes the oxidation of various substrates such as phenol and aniline in the presence of hydrogen peroxide via its iron-porphyrin catalytic center. This enzyme is widely used in industrial phenol removal, food additives, biomedicine, and clinical test reagents due to its rapid reaction rate and obvious reaction outcomes. However, the large-scale use of HRP in industrial applications still faces numerous challenges, including activity, stability, and sustainability. This study demonstrates that when peroxidase is immobilized in zwitterionic polymer hydrogels, polycarboxybetaine (PCB) and polysulfobetaine (PSB), the properties of the enzyme are improved. PCB and PSB-embedded HRP exhibit a 6.11 and 1.53 times increase in Kcat/Km value, respectively, compared to the free enzyme. The immobilized enzyme also experiences increased activity over a range of temperatures and better tolerance to extreme pH and organic solvents, including formaldehyde. In addition, immobilized HRP exhibits excellent performance in storage and reproducibility. Remarkably, PCB-HRP still retains 80% of the initial activity after a 6-week storage period and can still attain the initial catalytic level of the free enzyme after six repeated cycles. It also removes 90% of phenol within 12 min, surpassing the current pharmacy on the market. These experimental results indicated that we have successfully designed a set of stable and efficient support substrates for horseradish peroxidase, which enhances its suitability for deployment in industrial applications.

The interfacial region between two bulk media in organic semiconductor based devices, such as organic field-effect transistors (OFETs), organic light-emitting diodes, and organic photovoltaics, refers to the region where two different materials such as an organic material and an electrode come in contact with each other. Although the interfacial region contains a significantly smaller fraction of molecules compared to the bulk, it is the primary site where many photoinduced excited state processes occur, such as charge transfer, charge recombination, separation, energy transfer processes, etc. All such photoinduced processes have a dependence on molecular orientation and density of states at the interfaces, therefore having an understanding of the interfacial region is essential. However, conventional spectroscopic techniques, such as surface-enhanced Raman scattering, x-ray photoelectron spectroscopy, atomic force microscopy, etc., face limitations in probing the orientation and density of states of interfacial molecules. Therefore, there is a need for noninvasive techniques capable of efficiently investigating the interfaces. The electronic sum frequency generation (ESFG) technique offers an interface selectivity based on the principle that the second-order nonlinear susceptibility tensor, within the electric dipole approximation, is zero in the isotropic bulk but nonzero at interfaces. This selectivity makes ESFG a promising spectroscopy tool to probe the molecular orientation and density of states at the buried interface. For beginners interested in employing ESFG to study the density of states at the interface, a detailed description of the experimental setup is provided here.

With renewed interest in food packaging materials that can be both recyclable and compostable and the environmental concerns about plastic pollution in the terrestrial and aquatic ecosystems, molded fiber food packaging is experiencing an unprecedented demand around the globe. However, the phase-out of per- and polyfluoroalkyl substances (PFASs), commonly used as a water/grease resistant agent in food contact molded materials in many jurisdictions, has posed a significant challenge to the industry. This perspective outlines a recently developed solution to replace PFASs through the application of a layer of cellulose nanofibrils on the surface of molded fiber objects.

Per- and polyfluoroalkyl substances (PFAS) have been used to waterproof and greaseproof food serviceware for decades. Health concerns about these compounds have drawn attention to the potential for contamination of the food system. Finished compost (n = 3) made from manure and food serviceware labeled "compostable" generated at a large fair was found to contain 12 or 13 of the 28 PFAS compounds sampled for, in concentrations ranging from 1.1 to 183 μg/kg (Σ28PFAS range = 209-455 μg/kg). Of note, perfluorooctanoic acid, a known carcinogen, was found at concentrations between 47.2 and 55.5 μg/kg. In contrast, fresh manure contained only perfluoroctanesulfonic acid at 3.7 μg/kg, and separated food waste from the fair composted with grass clippings and livestock bedding had no detectable PFAS in 2022, and Σ28PFAS = 9.6 μg/kg in 2019. Including compostable serviceware in compost likely contaminates the finished compost and threatens surrounding groundwater and surface waters, in addition to increasing potential crop uptake.

This is the second half of a two-part Tutorial on the basics of the time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of bio-related samples. Part I of this Tutorial series covers planning for a ToF-SIMS experiment, preparing and shipping samples, and collecting ToF-SIMS data. This Tutorial aims at helping the ToF-SIMS user to process, display, and interpret ToF-SIMS data. ToF-SIMS provides detailed chemical information about surfaces but comes with a steep learning. The purpose of this Tutorial is to provide the reader with a solid foundation in the ToF-SIMS data analysis.