Chemical Surface Modification Research Articles

Immune-defensive microspheres promote regeneration of the nucleus pulposus by targeted entrapment of the inflammatory cascade during intervertebral disc degeneration

Sustained and intense inflammation is the pathological basis for intervertebral disc degeneration (IVDD). Effective antagonism or reduction of local inflammatory factors may help regulate the IVDD microenvironment and reshape the extracellular matrix of the disc. This study reports an immunomodulatory hydrogel microsphere system combining cell membrane-coated mimic technology and surface chemical modification methods by grafting neutrophil membrane-coated polylactic-glycolic acid copolymer nanoparticles loaded with transforming growth factor-beta 1 (TGF-β1) (T-NNPs) onto the surface of methacrylic acid gelatin anhydride microspheres (GM) via amide bonds. The nanoparticle-microsphere complex (GM@T-NNPs) sustained the long-term release of T-NNPs with excellent cell-like functions, effectively bound to pro-inflammatory cytokines, and improved the release kinetics of TGF-β1, maintaining a 36 day-acting release. GM@T-NNPs significantly inhibited lipopolysaccharide-induced inflammation in nucleus pulposus cells in vitro, downregulated the expression of inflammatory factors and matrix metalloproteinase, and upregulated the expression of collagen-II and aggrecan. GM@T-NNPs effectively restored intervertebral disc height and significantly improved the structure and biomechanical function of the nucleus pulposus in a rat IVDD model. The integration of biomimetic technology and nano-drug delivery systems expands the application of biomimetic cell membrane-coated materials and provides a new treatment strategy for IVDD.

Plasma Treatment Modifies Element Distribution in Seed Coating and Affects Further Germination and Plant Growth through Interaction with Soil Microbiome.

This study investigates the impact of plasma-seed interaction on germination and early plant development, focusing on Arabidopsis thaliana and Brassica napus. The investigation delves into changes in chemical composition, water absorption, and surface morphology induced by plasma filaments generated in synthetic air. These analyses were conducted using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Although plasma treatment enhanced water absorption and modified surface chemistry, its impact on germination demonstrated species- and context-dependent variations. Notably, the accelerated germination and morphogenesis of seedlings in microbiome-enriched (MB+) soil could be achieved also in microbiome-deprived (MB-) soil by short-term plasma treatment of seeds. Remarkably, the positive effects of plasma treatment on early developmental events (germination, morphogenesis) and later events (formation of inflorescences) were more pronounced in the context of MB- soil but were accompanied by a slight decrease in disease resistance, which was not detected in MB+ soil. The results underscore the intricate dynamics of plasma-plant interactions and stress the significance of accounting for the soil microbiome while designing experiments with potential field application.

Enhancing the dynamic thermal stability of metal oxide oil-based nanofluids through synchronous chemical modification and physical coating

The stability of oil-based nanofluid, especially dynamic thermal stability, hinders its practical application in industries. To enhance the stability of oil-based nanofluids, an excess amount of hexadecyl trimethoxysilane was employed to synchronously achieve chemical surface modification and physical coating of metal oxide nanoparticles. This process can efficiently render the nanoparticle surface lipophilic while introducing steric hindrance. The dynamic thermal stability and long-term durability of the nanofluids were confirmed through extended resting and thermal cycling experiments. Additionally, various characterization methods were employed to examine certain properties of the modified nanoparticles. The results reveal that the modified nanoparticles exhibit lipophilic characteristics, effective dispersion, and robust thermal stability. The nanofluids prepared using these modified nanoparticles remained stable for 3 months during resting periods and withstood 21 days of thermal cycling at 130 °C. This positions them as promising heat transfer mediums for mid-temperature industries. Importantly, this stabilization technique exhibits potential applicability across a wide range of hydrophilic metal oxide oil nanofluids, as suggested by mechanistic analysis. The exploration of dynamic thermal stability mechanisms is of great practical significance in promoting the large-scale application of nanofluids in industry and provides insights that could potentially resolve the longstanding challenge of nanofluid stability.

Interfacial Chemistry and Catalysis of Inorganic Materials.

Heterogeneous catalysis is essential to most industrial chemical processes. To achieve a better sustainability of these processes we need highly efficient and highly selective catalysts that are based on earth-abundant materials rather than the more conventional noble metals. Here, we discuss the potential of inorganic materials as catalysts for chemical transformations focusing in particular on the promising transition metal phosphides and sulfides. We describe our recent and current efforts to understand the interfacial chemistry of these materials that governs catalysis, and to tune catalytic reactivity by controlled chemical modification of the material surfaces and by use of interfacial electric fields.

Critical role of the composition of the cell culture medium on cell attachment and viability on PLA biocomposite scaffolds under in vitro assay conditions

In tissue engineering applications 3D scaffolds undertake the function of the native extracellular matrix (ECM) for cell attachment, survival, proliferation, and differentiation. For successful long-term implementation scaffolds need to mimic the ECM in vitro and in vivo. Many studies have focused on protein adsorption as the most critical factor for cell attachment. To improve protein adsorption on polymeric scaffolds various physical and chemical surface modification techniques, such as changing surface porosity, surface energy, and introducing various functional surface chemical groups have been investigated. It is well studied and documented that complex interactions between the biomaterial surface and the cell culture components in in vitro assay conditions define the scaffold performance. In this study influence of in vitro assay components on HepG2 liver cell attachment and proliferation on 3D printed poly(lactic acid) (PLA) scaffolds coated with various polymeric electrospun webs were investigated. MTT assays were performed on the scaffolds by using 3 different cell culture media; (i) basal cell culture medium (DMEM), (ii) DMEM supplemented with 10% albumin, and (iii) DMEM supplemented with 10% fetal bovine serum (FBS). Results obtained have shown dramatic improvement in cell attachment and proliferation in DMEM supplemented with 10% FBS when compared with DMEM and DMEM containing 10% albumin. Our findings clearly demonstrate synergistic effects of all bioactive components present in the FBS medium in significantly improving the HepG2 cell attachment and proliferation on polymeric scaffolds under in vitro conditions, regardless of the substrate structure, composition, and surface properties.

Chemical modification of nanotubular Ti surfaces with calcium phosphate and strontium ranelate for biomedical applications

Titanium (Ti) and its alloys are widely used as dental implants due to their notable properties, including corrosion resistance, biocompatibility, and mechanical stability. The anodization process can create a unique nanotubular (NT) structure on the surface of Ti, which offers significant potential for improving the performance of this biomaterial. This study deals with the chemical modification of an NT Ti surface by the incorporation of calcium phosphate (CaP) and strontium ranelate (SrR). A comprehensive set of analytical techniques was used to study these surface modifications on Ti, including atomic force microscopy, water contact angle measurements, scanning electron microscopy, thermal diffusivity, X-ray diffraction, and X-ray photoelectron spectroscopy. Examination of the surface morphology after immersion revealed the presence of deposits, occasionally with partial blocking of the TiO2 nanotubes. Both surface morphology and chemical analysis demonstrated the successful incorporation of CaP and SrR. In addition, in vitro evaluations demonstrated the exceptional promise of the prepared samples for biomedical applications, exhibiting high cell viability, non-toxicity, and osteogenic properties. These results underscore the potential of these modified surfaces to significantly advance the field of dental implantology.

Antifouling strategies for electrochemical sensing in complex biological media.

Surface fouling poses a significant challenge that restricts the analytical performance of electrochemical sensors in both in vitro and in vivo applications. Biofouling resistance is paramount to guarantee the reliable operation of electrochemical sensors in complex biofluids (e.g., blood, serum, and urine). Seeking efficient strategies for surface fouling and establishing highly sensitive sensing platforms for applications in complex media have received increasing attention in the past. In this review, we provide a comprehensive overview of recent research efforts focused on antifouling electrochemical sensors. Initially, we present a detailed illustration of the concept about biofouling along with an exploration of four key antifouling mechanisms. Subsequently, we delve into the commonly employed antifouling strategies in the fabrication of electrochemical sensors. These encompass physical surface topography (micro/nanostructure coatings and filtration membranes) and chemical surface modifications (PEG and its derivatives, zwitterionic polymers, peptides, proteins, and various other antifouling materials). The progress in antifouling electrochemical sensors is proposed concerning the antifouling mechanisms as well as sensing capability assessments (e.g., sensitivity, stability, and practical application ability). Finally, we summarize the evolving trends in the field and highlight some key remaining limitations.

Surface Modification of Polystyrene with Boronic Acid for Immunoaffinity-Based Cell Enrichment.

Obtaining an enriched and phenotypically pure cell population from heterogeneous cell mixtures is important for diagnostics and biosensing. Existing techniques such as fluorescent-activated cell sorting (FACS) and magnetic-activated cell sorting (MACS) require preincubation with antibodies (Ab) and specialized equipment. Cell immunopanning removes the need for preincubation and can be done with no specialized equipment. The majority of the available antibody-mediated analyte capture techniques require a modification to the Abs for binding. In this work, no antibody modification is used because we take advantage of the carbohydrate chain in the Fc region of Ab. We use boronic acid as a cross-linker to bind the Ab to a modified surface. The process allows for functional orientation and cleavable binding of the Ab. In this study, we created an immunoaffinity matrix on polystyrene (PS), an inexpensive and ubiquitous plastic. We observed a 37% increase in Ab binding compared with that of a passive adsorption approach. The method also displayed a more consistent antibody binding with 17 times less variation in Ab loading among replicates than did the passive adsorption approach. Surface topography analysis revealed that a dextran coating reduced nonspecific antibody binding. Elemental analysis (XPS) was used to characterize the surface at different stages and showed that APBA molecules can bind upside-down on the surface. While upside-down antibodies likely remain functional, their elution behavior might differ from those bound in the desired way. Cell capture experiments show that the new surface has 43% better selectivity and 2.4-fold higher capture efficiency compared to a control surface of passively adsorbed Abs. This specific surface chemistry modification will allow the targeted capture of cells or analytes with the option of chemical detachment for further research and characterization.

Synthesis of Photoluminescent 2D Self-Assembled Silver Thiolate Nanoclusters for Sensors and Biomolecule Support.

Silver thiolate nanoclusters (Ag NCs) show distinctive optical properties resulting from their hybrid nature, metallic and molecular, exhibiting size-, structure-, and surface-dependent photoluminescence, thus enabling the exploitation of Ag NCs for potential applications in nanobiotechnology, catalysis, and biomedicine. However, tailoring Ag NCs for specific applications requires achieving long-term stability and may involve modifying surface chemistry, fine-tuning ligand composition, or adding functional groups. In this study, we report the synthesis of novel Ag NCs using 2-ethanephenylthiolate (SR) as a ligand, highlight critical points addressing stability, and characterize their optical and structural properties. A preliminary electrical characterization revealed high anisotropy, well suited for potential use in electronics/sensing applications. We also present the synthesis and characterization of Ag NCs using 10-carboxylic 2-ol thiolate (SR'COOH) having a terminal carboxylic group for conjugation with amine-containing molecules. We present a preliminary assessment of its bioconjugation capability using bovine serum albumin as a model protein indicating its prospective application as a biomolecule support.

Comparable Toxicity of Surface-Modified TiO2 Nanoparticles: An In Vivo Experimental Study on Reproductive Toxicity in Rats.

Nanoparticles (NPs), a distinct class of particles ranging in size from 1 to 100 nm, are one of the most promising technologies of the 21st century, and titanium dioxide NPs (TiO2 NPs) are among the most widely produced and used NPs globally. The increased application of TiO2 NPs raises concerns regarding their global safety and risks of exposure. Many animal studies have reported the accumulation of TiO2 NPs in female reproductive organs; however, evidence of the resultant toxicity remains ambiguous. Since the surface area and chemical modifications of NPs can significantly change their cytotoxicity, we aimed to compare the toxic effects of pristine TiO2 powder with surface-modified TiO2 powders with salicylic acid (TiO2/SA) and 5-aminosalicylic acid (TiO2/5-ASA) on the ovaries, oviducts, and uterus on the 14th day following acute oral treatment. The results, based on alterations in food and water intake, body mass, organ-to-body mass ratio, hormonal status, histological features of tissues of interest, and antioxidant parameters, suggest that the modification with 5-ASA can mitigate some of the observed toxic effects of TiO2 powder and encourage future investigations to create NPs that can potentially reduce the harmful effects of TiO2 NPs while preserving their positive impacts.

Surface modification strategies of 304 austenitic stainless steel plate with different micromorphology and composition for improved mechanical interlocking and chemical bonding in metal–epoxy joints

304 austenitic stainless-steel (SS) strip-based carbon fiber metal laminates (CFMLs) have raised significant concerns, in terms of their mechanical performance. On top of that, the hybrid laminates’ interlamination performance is vital in regulating their failure patterns. Along these lines, in this work, SS strips with regulatable micromorphology and composition were obtained by using physical and chemical surface modification strategies, including polishing, acid etching, anodization, and thermal treatment. The shear strength of the treated-SS/epoxy single lap joints (two treated-SS strips bonded by the epoxy resin via hot curing process) was systematically explored, and the origins of the enhancement mechanism were attributed to the resulting surface microstructure, as well as the possible chemical reactions between the treated surface and the curing agent. The etching-anodizing-thermally treated-SS (EAT-SS)/epoxy joint exhibited the maximum shear strength (16.04 MPa) and work of fracture (5.85 kJ·m−2) due to the substantial cohesive failure pattern of the epoxy. The encouraging enhancement was mainly attributed to the synergistic effect of the micro-annular pit and the nanoporous array structure of the EAT-SS surface. These effects induced a significant mechanical interlock and a plausible chemical reaction at the interface, which led to improved bonding strength between the epoxy and treated-SS surface. Overall, in this work, it was demonstrated that the combination of the anodization and thermal treatment can effectively improve the interlamination bonding properties between the SS strip and the epoxy resin due to the combination effect of mechanical interlocking and chemical bonding.

Broadband-Tunable Vanadium Dioxide (VO2)-Based Linear Optical Cavity Sensor.

Sensors fabricated by using a silicon-on-insulator (SOI) platform provide promising solutions to issues such as size, power consumption, wavelength-specific nature of end reflectors and difficulty to detect ternary mixture. To address these limitations, we proposed and investigated a broadband-thermally tunable vanadium dioxide (VO2)-based linear optical cavity sensor model using a finite element method. The proposed structure consists of a silicon wire waveguide on a silicon-on-insulator (SOI) platform terminated with phase-change vanadium oxide (VO2) on each side to provide light confinement. A smooth transmission modulation range of 0.8 (VO2 in the insulator state) and 0.03 (VO2 in the conductive phase state) in the 125 to 230 THz spectral region was obtained due to the of Fabry-Pérot (FP) effect. For the 3.84 μm cavity length, the presented sensor resulted in a sensitivity of 20.2 THz/RIU or 179.56 nm/RIU, which is approximately two orders of magnitude higher than its counterparts in the literature. The sensitivity of the 2D model showed direct relation with the length of the optical cavity. Moreover, the change in the resonating mode line width Δν of approximately 6.94 THz/RIU or 59.96 nm/RIU was also observed when the sensor was subjected to the change of the imaginary part k of complex refractive index (RI). This property of the sensor equips it for the sensing of aternary mixture without using any chemical surface modification. The proposed sensor haspotential applications in the areas of chemical industries, environmental monitoring and biomedical sensing.

Nanocomposites Based on Thermoplastic Acrylic Resin with the Addition of Chemically Modified Multi-Walled Carbon Nanotubes.

The main goal of this work was an improvement in the mechanical and electrical properties of acrylic resin-based nanocomposites filled with chemically modified carbon nanotubes. For this purpose, the surface functionalization of multi-walled carbon nanotubes (MWCNTs) was carried out by means of aryl groups grafting via the diazotization reaction with selected aniline derivatives, and then nanocomposites based on ELIUM® resin were fabricated. FT-IR analysis confirmed the effectiveness of the carried-out chemical surface modification of MWCNTs as new bands on FT-IR spectra appeared in the measurements. TEM observations showed that carbon nanotube fragmentation did not occur during the modifications. According to the results from Raman spectroscopy, the least defective carbon nanotube structure was obtained for aniline modification. Transmission light microscopy analysis showed that the neat MWCNTs agglomerate strongly, while the proposed modifications improved their dispersion significantly. Viscosity tests confirmed, that as the nanofiller concentration increases, the viscosity of the mixture increases. The mixture with the highest dispersion of nanoparticles exhibited the most viscous behaviour. Finally, an enhancement in impact resistance and electrical conductivity was obtained for nanocomposites containing modified MWCNTs.

Well-established carbon nanomaterials: modification, characterization and dispersion in different solvents

Three different types of carbon nanomaterials, SWCNTs, MWCNTs and GNPs were prepared, modified, characterized, and their dispersibility behavior in three different solvents was evaluated. The carbon nanotubes were synthesized by using the well-known chemical vapor deposition method and the graphene nanoplatelets by wet physicochemical treatment techniques. Their characterization was accomplished by using various advanced techniques, such as powder X-ray diffraction and Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and N2 adsorption at 77 K. Furthermore, the carbon nanostructures were modified via plasma treatment and wet chemical surface modification in order to enhance their dispersion characteristics, for achieving more homogenous suspensions and therefore to be remained dispersed over a reasonable period of time without any sedimentation. The effect of treatment parameters and the use of different solvents were thoroughly studied mainly by optical methods, but also by using the DIN/EN classified ISO method of oil absorption and UV–Vis spectroscopy. The enhanced dispersion rate is observed in both CNTs and GNPs materials following their surface treatment, especially when using the solvent n-methyl-2-pyrrolidone. The aforementioned studied nanomaterials are perfect candidate fillers for preparing polymeric mixed matrix membranes.Graphical abstract

Defect passivation in methylammonium/bromine free inverted perovskite solar cells using charge-modulated molecular bonding

Molecular passivation is a prominent approach for improving the performance and operation stability of halide perovskite solar cells (HPSCs). Herein, we reveal discernible effects of diammonium molecules with either an aryl or alkyl core onto Methylammonium-free perovskites. Piperazine dihydriodide (PZDI), characterized by an alkyl core-electron cloud-rich-NH terminal, proves effective in mitigating surface and bulk defects and modifying surface chemistry or interfacial energy band, ultimately leading to improved carrier extraction. Benefiting from superior PZDI passivation, the device achieves an impressive efficiency of 23.17% (area ~1 cm2) (low open circuit voltage deficit ~0.327 V) along with superior operational stability. We achieve a certified efficiency of ~21.47% (area ~1.024 cm2) for inverted HPSC. PZDI strengthens adhesion to the perovskite via -NH2I and Mulliken charge distribution. Device analysis corroborates that stronger bonding interaction attenuates the defect densities and suppresses ion migration. This work underscores the crucial role of bifunctional molecules with stronger surface adsorption in defect mitigation, setting the stage for the design of charge-regulated molecular passivation to enhance the performance and stability of HPSC.

Chemical surface modification of carbon dots with Germanium: A highly sensitive and selective ratiometric fluorescence probe for Mg2+ detection using DFT and TD-DFT

In this study, we chemically modified carbon dots (Cdots) using germanium, enhancing their sensitivity and selectivity as a ratiometric fluorescence probe for precise detection of Mg2+ ions. Excitation of the modified Cdots resulted in a distinct emission peak at 527 nm, enabling accurate measurement of Mg2+ concentrations across a linear range. The surface modification with germanium led to the creation of novel emitting centers on the Cdots' surface. Theoretical calculations using density functional theory (DFT) revealed the effective suppression of these emitting centers through a photo-induced electron transfer (PET) process, utilizing the nitrogen lone pair electrons on the Cdots' surface. Furthermore, adjacent Cdots' surface pyrazino[2,3-f][1,10]-phenanthroline (PPT) nitrogen atoms formed chemical bonds with Mg2+ ions, resulting in the formation of aggregated Cdots. Consequently, the intricate complexation terminated the PET process, resulting in a novel emission peak at longer wavelengths. This study presents a highly sensitive and selective ratiometric fluorescent detection system with exceptional low concentration detection limit for precise Mg2+ ion detection.

Erimiş Filament Üretim Yöntemi ile Üretilen Kompozit Yapılarda Yöne Bağlı Yüzey Özelliklerinin İncelenmesi ve İyileştirilmesi

Additive manufacturing methods, which have begun to be used in final product production beyond producing prototypes, are popular research topics today. The Fused Filament Fabrication (FFF) method, which has a wider usage area and user base, is the most well-known among these methods. The method in which the polymer is extruded in layers has advantages such as design freedom and topology optimization, as well as disadvantages such as surface roughness and low production speed. The number of materials that can be used in the FFF method is diversifying day by day, and polymeric composites can also be produced beyond pure polymers. The use of engineering polymers such as polyamide in this production method creates many new opportunities. In addition, the start of production of short fiber reinforced polymeric composites has paved the way to produce high-performance final products. In this study, the effects of parameters such as layer thickness and printing orientation on the surface roughness of samples produced using polyamide and short carbon fiber reinforced polymer matrix composite materials were examined. Chemical surface treatment was applied to the surfaces of 3D-printed samples to improve surface roughness. It was concluded that the increase in layer thickness increases the surface roughness, the -/+45 filling orientation creates higher roughness than the 0 and 90 orientations, and the surface quality can be increased by chemical surface modification.

Review of: "In many cases, surface chemical modifications are required to create active groups that can bind to biomolecules"

Review of: "In many cases, surface chemical modifications are required to create active groups that can bind to biomolecules"

Chemical surface modification of mesoporous SiO2-based membranes for fine-tuning of drug loading and release properties

Transdermal Drug Delivery Systems (TDDS) show significant advantages over other forms of drug application. Despite their clinical use for decades, these drug delivery devices have yet to reach their full potential. While polymer matrices are most commonly used as transdermal patches so far, inorganic carriers like mesoporous silica membranes offer several advantages, including chemical stability and their tunable porous system, with adjustable pore sizes, pore volumes and surface chemistries. In this study, we chemically modified high and low porosity mesoporous silica membranes by post-synthetic methods and compared the effects of different surface modifications on loading efficacies and release profiles of different pharmacologically relevant drugs with different chemical properties. Drug loading capacities and release profiles were substantially affected by pore structure and surface modifcations with strongly acidic SO3H groups or hydrophobic methyl groups, while weakly acidic COOH groups or nitrile groups showed little effects. SO3H modification of low porosity (LP) membranes led to markedly increased loading capacity and a more sustained release profile of anastrozole. The latter was also observed for xylazine, but associated with lesser drug loading. Likewise, the SO3H modification also slowed down the release of imiquimod or flunixin. Increasing LP membrane hydrophobicity by methyl modification essentially abolished anastrozole drug loading. In high porosity (HP) membranes, effects of chemical surface modifications were overall weaker. This led to particularly slow anastrozole or xylazine release profiles from methyl-modified membranes. Biocompatibility studies showed some cell-inhibitory effects of CN functionalization, but full biocompatibility of SO3H functionalized membranes as indicated by efficient cell attachment and high viability. Both parameters, pore structure and chemical surface modifcations, drug-dependently affect drug loading and release properties. Since they can be precisely fine-tuned in mesoporous silica membranes, this allows for the development of optimized TDDS providing high drug loading and the desired release profile of a given drug. Our results presented here indicate that the SO3H modification is particularly useful in this regard.

A triboelectric nanogenerator using degradable surface-modified cellulose acetate and ferroelectric gelatin composite nanofibers

High output performance of degradable triboelectric nanogenerators (TENGs) is achieved by synergistically combining nanofibrous structures, chemical surface modification, and composite formation using ferroelectric fillers.