Biological Environment Research Articles

Ca/P in situ introduction for enhancing coating biocompatibility via plasma electrolytic oxidation in low-temperature molten salt.

Plasma electrolytic oxidation (PEO) is one of the most promising methods for synthesizing ceramic coatings on metallic substrates. Recently, PEO in molten salt electrolytes was found to be advantageous due to overcoming system heating and the formation of contaminants. However, the PEO in molten salt was conducted at a high temperature (Tm∼220 °C), limiting the introduction of different components such as Ca and P. This study realizes the employment of a low-temperature electrolyte based on a ternary eutectic system of Ca(NO3)2-NaNO3-KNO3 (Tm∼130 °C) jointly with the in situ introduction of Ca/P in the form of ammonium dihydrogen phosphate (ADP). The surface morphology, phase and chemical composition, wettability, and anti-corrosion performance were examined. The results indicate improved surface performance with the addition of 1 wt.% ADP to the electrolyte. This surface preferably comprises the anatase phase of TiO2 and exhibits enhanced biocompatibility and corrosion resistance in a biological environment.

Biological evaluation of femtosecond-laser-textured Fe–Mn alloys for vascular applications

Biodegradable metals represent a valuable solution for the development of temporary vascular implants. These are expected to dissolve in the body over time, avoiding side effects typical of permanent implants, such as thrombosis, in-stent restenosis and chronic inflammation. Iron (Fe)-based alloys, such as iron–manganese (Mn) alloys, are of particular interest for cardiovascular applications due to their intrinsic properties. However, their degradation behavior and biological performance need to be improved. Femtosecond (fs)-laser-induced surface topography could affect both their degradation and cell–material interaction. In this work, fs-laser-induced patterning was performed on a Fe–Mn20 alloy to tune both the degradation behavior of the material and its interaction with the biological environment for cardiovascular applications. Processing parameters were varied to select an optimized surface morphology, characterized by linear grooves. Profilometric analysis, scanning electron microscopy and degradation rate analysis were performed on the treated samples. Thereafter, endothelial cell viability tests and hemocompatibility assessment were carried out on selected process conditions. The obtained fs-laser-induced linear patterns were demonstrated to decrease the degradation rate and to improve the biological response toward both endothelial cells and blood. These results demonstrate how fs-laser-induced patterning is a promising solution for the development of biodegradable metal-based vascular implants.

Competition between O-H and S-H Intermolecular Interactions in Conformationally Complex Systems: The 2-Phenylethanethiol and 2-Phenylethanol Dimers.

Noncovalent interactions involving sulfur centers play a relevant role in biological and chemical environments. Yet, detailed molecular descriptions are scarce and limited to very simple model systems. Here we explore the formation of the elusive S-H···S hydrogen bond and the competition between S-H···O and O-H···S interactions in pure and mixed dimers of the conformationally flexible molecules 2-phenylethanethiol (PET) and 2-phenylethanol (PEAL), using the isolated and size-controlled environment of a jet expansion. The structure of both PET-PET and PET-PEAL dimers was unraveled through a comprehensive methodology that combined rotationally resolved microwave spectroscopy, mass-resolved isomer-specific infrared laser spectroscopy, and quantum chemical calculations. This synergic experimental-computational approach offered unique insights into the potential energy surface, conformational equilibria, molecular structure, and intermolecular interactions of the dimers. The results show a preferential order for establishing hydrogen bonds following the sequence S-H···S < S-H···O ≲ O-H···S < O-H···O, despite the hydrogen bond only accounting for a fraction of the total interaction energy.

Ecology as an Aid to Floristics I : Adaptation and Ecotypes

The paper aims to demonstrate the role of the biological environment in shaping a plant species. Genetically and physiologically controlled demands and range of tolerance and their interactions produce a mosaic of populations. It is in these populations that 'ecads' and 'ecotypes are distinguished.The paper gives suitable examples of adaptations, ecads and ecotypes.This has opened a new line of work in taxonomic studies. Slight differences in morphological or even physiological characters of otherwise similar species should not be taken to separate the spécies taxonomically. Only ecological experimentation will provide the final answer.

Surface modification of biomedical titanium alloy for hard tissue repair and reconstruction

In biomedical applications, various materials are used, including metals and their alloys, polymers and ceramics. Among them, titanium (Ti) and titanium alloys are widely utilised in implant materials due to their excellent corrosion resistance and high mechanical strength. However, despite these advantages, titanium is biologically inert and does not integrate well with human cells. Therefore, surface modification of titanium implants plays a crucial role in determining the rate of osseointegration and the overall success of the implants. The primary objective of this review is to provide a detailed introduction to surface modification technologies for titanium alloy implants. The aim is to enhance the biological activity, wear resistance, corrosion resistance and antibacterial properties and reduce the release of ions from the implants. By modifying the surface of titanium implants, it is possible to create a more favourable environment for cell adhesion, proliferation and differentiation. Various techniques, such as physical methods (e.g. sandblasting, acid etching) and chemical methods (e.g. surface oxidation, plasma treatment) can be employed to modify the surface properties of titanium implants. These surface modification techniques can enhance the interaction between the implant and the surrounding biological environment, promoting osseointegration and improving the long-term stability of the implant. Additionally, surface modifications can help reduce the release of potentially harmful ions from the implant, minimise bacterial adhesion and improve the overall biocompatibility of the implant. In conclusion, surface modification of titanium alloy implants is a critical aspect of biomedical engineering. By improving the biocompatibility of titanium implants, these modifications contribute to the success and longevity of implants used in hard tissue repair and reconstruction.

Design and application of Cd2+ polypeptide fluorescent probes based on Aggregation Induced Emission (AIE).

Cadmium is a toxic heavy metal, which is both an environmental pollutant, and a threat to human health. A fluorescent probe was developed to detect Cd2+ selectively, sensitively, and quickly. This study reports the successful development of a polypeptide fluorescent probe TPE-HC (TPE-His-Pro-Gly-Cys) which selectively detects Cd2+ by Aggregation-Induced Emission effect. After fluorescence excitation, Cd2+ can be effectively detected based on the change of fluorescence intensity. The detection limit of Cd2+ in buffer solution was determined to be 151 nM (R2 = 0.9933). This probe exhibits high sensitivity, high cell permeabilit y, and low biological toxicity, and can perform live cell imaging under biological conditions. This study indicates that TPE-HC can detect Cd2+ in biological environments.

Light‐Driven Micronavigators for Directional Migration of Cells

AbstractCell migration is an essential physiological process in the life cycle of cells, playing a crucial role in cancer metastasis, neural development, and cellular immune response. However, achieving precise control of cell migration at single‐cell level is challenging due to the intricate and diverse microenvironments of cells. Here, an optical technique is presented that utilizes light‐actuated micronavigators to guide the directional migration of individual cells both in vitro and in vivo. Employing high‐speed scanning optical tweezers, micronavigators near target cells are trapped and rotated at a rotation speed of up to 12 000 rpm, which, to the best of knowledge, represents the fastest rotation of light‐driven micromotors in a biological environment to date. The micronavigators generate a powerful fluid shear force (up to 40 pN) which can guide the migration of immune and nerve cells in a predetermined direction. Furthermore, micronavigators are employed to guide cell migration in various biological systems, including lab‐on‐a‐chip devices and blood vessels within living animals. This technique offers new opportunities for controlling cell migration, enabling precise immune activation, and neuron repair at the single‐cell level.

Spatial and Temporal Assessment of Baseflow Based on Monthly Water Balance Modeling and Baseflow Separation

Baseflow is the part of streamflow that is mainly replenished by groundwater. The protection of the biological environment and the growth of its water resources greatly depend on the spatial and temporal evolution of baseflow. Therefore, the Baizhiao (BZA) and Shaduan (SD) catchments of the Jiaojiang River Basin (JRB) in the Zhejiang province of China were selected as study areas. The ABCD model and Eckhardt method were used to calculate baseflow and baseflow index (BFI). The temporal and spatial evolution patterns of baseflow were analyzed through statistical analysis and the Mann–Kendall test. The results showed that the ABCD model performs well in simulating overall hydrological processes on the monthly streamflow at BAZ and SD stations with NSE (Nash–Sutcliffe Efficiency) values of 0.82 and 0.83 and Pbias (Percentage Bias) values of 9.2% and 8.61%, respectively. The spatial–temporal distribution of the BFI indicates the higher baseflow contribution in upstream areas compared to downstream areas at both stations. The baseflow and BFI had significant upward trends at the BZA and SD stations in the dry season, while their trends were not uniform during the wet period. These findings are essential guidance for water resource management in the JRB regions.

Recent Advances in Magnesium–Magnesium Oxide Nanoparticle Composites for Biomedical Applications

Magnesium (Mg) is considered an attractive option for orthopedic applications due to its density and elastic modulus close to the natural bone of the body, as well as biodegradability and good tensile strength. However, it faces serious challenges, including a high degradation rate and, as a result, a loss of mechanical properties during long periods of exposure to the biological environment. Also, among its other weaknesses, it can be mentioned that it does not deal with bacterial biofilms. It has been found that making composites by synergizing its various components can be an efficient way to improve its properties. Among metal oxide nanoparticles, magnesium oxide nanoparticles (MgO NPs) have distinct physicochemical and biological properties, including biocompatibility, biodegradability, high bioactivity, significant antibacterial properties, and good mechanical properties, which make it a good choice as a reinforcement in composites. However, the lack of comprehensive understanding of the effectiveness of Mg NPs as Mg matrix reinforcements in mechanical, corrosion, and biological fields is considered a challenge in their application. While introducing the role of MgO NPs in medical fields, this article summarizes the most important results of recent research on the mechanical, corrosion, and biological performance of Mg/MgO composites.

Electrophoresis-Based Approach for Characterizing Dendrimer-Protein Interactions: A Proof-of-Concept Study.

Improving the clinical translation of nanomedicine requires better knowledge about how nanoparticles interact with biological environments. As researchers are recognizing the importance of understanding the protein corona and characterizing how nanocarriers respond in biological systems, new tools and techniques are needed to analyze nanocarrier-protein interactions, especially for smaller size (<10 nm) nanoparticles like polyamidoamine (PAMAM) dendrimers. Here, we developed a streamlined, semiquantitative approach to assess dendrimer-protein interactions using a nondenaturing electrophoresis technique combined with mass spectrometry. With this protocol, we detect fluorescently tagged dendrimers and proteins simultaneously, enabling us to analyze when dendrimers migrate with proteins. We found that PAMAM dendrimers mostly interact with complement proteins, particularly C3 and C4a, which aligns with previously published data, verifying that our approach can be used to isolate and identify dendrimer-protein interactions.

MR-GGI: accurate inference of gene–gene interactions using Mendelian randomization

BackgroundResearchers have long studied the regulatory processes of genes to uncover their functions. Gene regulatory network analysis is one of the popular approaches for understanding these processes, requiring accurate identification of interactions among the genes to establish the gene regulatory network. Advances in genome-wide association studies and expression quantitative trait loci studies have led to a wealth of genomic data, facilitating more accurate inference of gene–gene interactions. However, unknown confounding factors may influence these interactions, making their interpretation complicated. Mendelian randomization (MR) has emerged as a valuable tool for causal inference in genetics, addressing confounding effects by estimating causal relationships using instrumental variables. In this paper, we propose a new statistical method, MR-GGI, for accurately inferring gene–gene interactions using Mendelian randomization.ResultsMR-GGI applies one gene as the exposure and another as the outcome, using causal cis-single-nucleotide polymorphisms as instrumental variables in the inverse-variance weighted MR model. Through simulations, we have demonstrated MR-GGI's ability to control type 1 error and maintain statistical power despite confounding effects. MR-GGI performed the best when compared to other methods using the F1 score on the DREAM5 dataset. Additionally, when applied to yeast genomic data, MR-GGI successfully identified six clusters. Through gene ontology analysis, we have confirmed that each cluster in our study performs distinct functional roles by gathering genes with specific functions.ConclusionThese findings demonstrate that MR-GGI accurately inferences gene–gene interactions despite the confounding effects in real biological environments.

Bioabsorbable composite laminates of PLA reinforced with surface‐modified Mg wires for orthopedic implant applications

Unidirectional and multidirectional laminates of Mg wire‐reinforced PLA‐matrix composites were manufactured by an improved compression molding strategy that allows excellent control on the position and orientation of the wires. Two different types of Mg wires, with and without surface modification by continuous plasma electrolytic oxidation were used, the former to improve the interfacial strength and to reduce the degradation rate of Mg wires in biological environments. The mechanical properties of the constituents as well as of composites were measured before and after degradation by immersion in simulated body fluids and the corresponding deformation, fracture and degradation mechanisms were analyzed in detail. It was found that the presence of the Mg wires improved the mechanical behavior in tension and compression of unidirectional composites in the longitudinal direction (close to cortical bone) and that quasi‐isotropic laminates with tailored properties could be designed from the data of unidirectional composites.This article is protected by copyright. All rights reserved.

Printing Ochre

The discipline of geology was relatively new at the start of the United States Geological Survey (USGS) in the late 1800s, but through the organisation of an efficient government bureau and the voice of its printed page, it became a dominant perspective in the way generations of citizens relate to and view the natural world, human and nonhuman, life and nonlife. I choose to position my press in direct opposition to the maintenance of these dualisms. I will argue the critical role of print in facilitating USGS domination of terrestrial beings in a practical sense, yet beyond the methods and reach of publication, I believe the products of the USGS mediate our understanding of and relation to these beings. Instead, design practices can be directed towards changing attitudes and understanding between humans and nonhumans. Monika Bakke argues for the importance of artistic endeavours in addressing our collective futurity: Drawing on both life’s mineral origins and its key role in shaping mineral species, artists are turning to technoscience in order to develop, outside expert circles, better understanding of physical, chemical, and biological environments, not just of the geological past but also those to come in the future. ... Yet, their methodologies are specific to art which offers creative ontological and ethical contributions to public debate. (2017, p. 43) I am developing a design research paradigm relating to ochre as an epistemic tool for human and nonhuman intersubjectivity and ontological reconciliation or reunification between life and nonlife. I model my practice after a simplification of the USGS: to survey (observe, describe, collect) and to report (archive, document, record), with some critical variance in method and outcomes.

Boron Cluster Renders Organic Radicals Water-Stable for Photothermal Anti-Infections.

Water-stable organic radicals are promising photothermal conversion candidates for photothermal therapy (PTT). However, organic radicals are usually unstable in biological environments, which greatly hinders their wide application. Here, we have developed a chaotropic effect-based and photoinduced water-stable supramolecular radical (MB12-2) for efficient antibacterial PTT. The supramolecular radical precursor MB12-1 was constructed by the chaotropic effect between closo-dodecaborate cluster (B12H122-) and N,N'-dimethylated dipyridinium thiazolo [5,4-d] thiazole (MPT2+). Subsequently, with triethanolamine (TEOA) serving as an electron donor, MB12-1 could transform to its radical form MB12-2 through photoinduced electron transfer (PET) under 435-nm laser irradiation. The N2 adsorption-desorption analysis confirmed that MB12-2 was tightly packed through the introduction of B12H122-, which effectively enhanced its stability via a spatial site-blocked effect. Moreover, the half-life of MB12-2 in water was calculated through ultraviolet-visible light (UV-vis) absorption spectra results for periods as long as 20 days. In addition, in the skin infection model, MB12-2, as a wound dressing, showed remarkable photothermal antibacterial activity (>97%) under 660-nm laser irradiation and promoted wound healing. This study presents a simple method for designing long-term water-stable supramolecular radicals, offering a novel avenue for noncontact treatments for bacterial infections.

Heterogeneous Sensor-Carrier Microswarms for Collaborative Precise Drug Delivery toward Unknown Targets with Localized Acidosis.

Micro/nanorobots hold the potential to revolutionize biomedicine by executing diverse tasks in hard-to-reach biological environments. Nevertheless, achieving precise drug delivery to unknown disease sites using swarming micro/nanorobots remains a significant challenge. Here we develop a heterogeneous swarm comprising sensing microrobots (sensor-bots) and drug-carrying microrobots (carrier-bots) with collaborative tasking capabilities for precise drug delivery toward unknown sites. Leveraging robust interspecific hydrodynamic interactions, the sensor-bots and carrier-bots spontaneously synchronize and self-organize into stable heterogeneous microswarms. Given that the sensor-bots can create real-time pH maps employing pH-responsive structural-color changes and the doxorubicin-loaded carrier-bots exhibit selective adhesion to acidic targets via pH-responsive charge reversal, the sensor-carrier microswarm, when exploring unknown environments, can detect and localize uncharted acidic targets, guide itself to cover the area, and finally deploy therapeutic carrier-bots precisely there. This versatile platform holds promise for treating diseases with localized acidosis and inspires future theranostic microsystems with expandability, task flexibility, and high efficiency.

Investigating the Effect of Carbon Nanomaterials Reinforcing Poly(ε-Caprolactone) Printed Scaffolds for Bone Repair Applications.

Scaffolds, three-dimensional (3D) substrates providing appropriate mechanical support and biological environments for new tissue formation, are the most common approaches in tissue engineering. To improve scaffold properties such as mechanical properties, surface characteristics, biocompatibility and biodegradability, different types of fillers have been used reinforcing biocompatible and biodegradable polymers. This paper investigates and compares the mechanical and biological behaviors of 3D printed poly(ε-caprolactone) scaffolds reinforced with graphene (G) and graphene oxide (GO) at different concentrations. Results show that contrary to G which improves mechanical properties and enhances cell attachment and proliferation, GO seems to show some cytotoxicity, particular at high contents.

The Influence of Blood and Serum Microenvironment on Spin-Labeled Magnetic Nanoparticles

The investigation and clarification of the properties of surface-functionalized superparamagnetic nanoparticles in a biological environment are key challenges prior to their medical applications. In the present work, electron paramagnetic resonance spectroscopy (EPR) combined with the spin labeling technique was utilized to better understand the behavior of nitroxides attached to magnetite nanoparticles dispersed in body fluid. EPR spectra of spin-labeled, silane-coated Fe3O4 nanoparticles in human serum and whole blood were recorded and analyzed for both room- and low-temperature values. In all cases, the obtained EPR signal consisted of a broad line from magnetite cores and a characteristic signal from the attached 4-Amino-2,2,6,6-tetramethylpiperidine-1-oxyl (4-amino-TEMPO). Even for liquid samples, the anisotropic components of magnetic tensors did not fully average out, which was reflected in the differences in the intensity of three narrow hyperfine lines from nitroxide. At 230 K the irregular slow-motion signal from the attached radical was also simulated using the EasySpin toolbox, which allowed to determine the parameters related to magnetic tensors and the dynamics of the spin label. The study showed that the anisotropy of the motion of the spin label 4-amino-TEMPO reflects its interactions with the surrounding medium and the manner of the attachment of the nitroxide to the surface of nanoparticles.

A Dual-Cascade Activatable Near-Infrared Fluorescent Probe for Precise Intraoperative Imaging of Tumor.

Accurate intraoperative tumor delineation is critical to achieving successful surgical outcomes. However, conventional techniques typically suffer from poor specificity and low sensitivity and are time-consuming, which greatly affects intraoperative decision-making. Here, we report a cascade activatable near-infrared fluorescent (NIRF) probe IR780SS@CaP that can sequentially respond to tumor acidity and elevated glutathione levels for accurate intraoperative tumor localization. Compared with nonactivatable and single-factor activatable probes, IR780SS@CaP with a cascade strategy can minimize nonspecific activation and false positive signals in a complicated biological environment, affording a superior tumor-to-normal tissue ratio to facilitate the delineation of abdominal metastases. Small metastatic lesions that were less than 1 mm in diameter can be precisely identified by IR780SS@CaP and completely excised under NIRF imaging guidance. This study could benefit tumor diagnosis and image-guided tumor surgery by providing real-time information and reliable decision support, thus reducing the risk of both recurrence and complications to improve patient outcomes.

Hydrogel/MOF Dual-Modified Photoelectrochemical Biosensor for Antibiofouling and Biocompatible Dopamine Detection.

For accurate in vivo detection, nonspecific adsorption of biomacromolecules such as proteins and cells is a severe issue. The adsorption leads to electrode passivation, significantly compromising both the sensitivity and precision of sensing. Meanwhile, common antibiofouling modifications, such as polymer coatings, still grapple with issues related to biocompatibility, electrode passivation, and miniaturization. Herein, we propose a composite antibiofouling coating strategy based on zwitterionic metal-organic frameworks (Z-MOFs) and a combination of acrylamide hydrogels. On a well-designed TiO2/Z-MOF/hydrogel photoelectrode, we achieve highly sensitive and selective detection of dopamine in complex biological environments. The hydrogel's three-dimensional porous structure combined with unique microporous architecture of Z-MOF ensures effective sieving of interfering macromolecules while preserving efficient small molecules and electron transport. This innovative approach paves the way for constructing miniature, in vivo antibiofouling sensors for molecule monitoring in living organisms with complicated chemical environments.

Enhanced Thin‐Film Encapsulation Through Micron‐Scale Anchors

AbstractImplantable medical devices require protective encapsulation to isolate them from the biological environment. Parylene‐C (PaC) is a prevalent encapsulation polymer but is susceptible to cracking, delamination, oxidation, and moisture penetration over time. This study demonstrates that 3D micro‐anchors fabricated by direct laser writing (DLW) greatly enhance PaC lifetime and encapsulation properties. The PaC film is vapor deposited onto these anchor points, followed by ultraviolet radiation (UV)‐curing‐induced shrinkage. Electrochemical impedance spectroscopy (EIS) during accelerated aging tests in reactive solutions (87 °C, 15 mM H2O2) is performed to monitor film degradation over time. Unpatterned PaC films failed before reaching the 3.25 accelerated year benchmark, while 100 µm spaced micro‐anchors extended encapsulation up to 5.5 equivalent years. Subsequent improvements are achieved with a spacing of 50 µm, demonstrating viability up to ≈6 equivalent years. This research demonstrates the benefit of engineering anchor points for preventing delamination of the PaC layer and significantly enhancing encapsulation properties. Printed 3D micro‐anchors are an extremely flexible platform, with many different shapes and sizes possible which can further enhance longevity. The success in increasing coating lifetimes offers a promising direction for improving long‐term implantable medical devices, potentially revolutionizing their longevity and reliability.