Surface Functionalization Research Articles

Size, polyglycerol grafting, and net surface charge of iron oxide nanoparticles determine their interaction and toxicity in Caenorhabditis elegans

The widespread application of engineered nanoparticles (NPs) in environmental remediation has raised public concerns about their toxicity to aquatic organisms. Although appropriate surface modification can mitigate the ecotoxicity of NPs, the lack of polymer coating to inhibit toxicity completely and the insufficient knowledge about charge effect hinder the development of safe nanomaterials. Herein, we explored the potential of polyglycerol (PG) functionalization in alleviating the environmental risks of NPs. Iron oxide NPs (ION) of 20, 100, and 200 nm sizes (IONS, IONM and IONL, respectively) were grafted with PG to afford ION-PG. We examined the interaction of ION and ION-PG with Caenorhabditis elegans (C. elegans) and found that PG suppressed non-specific interaction of ION with C. elegans to reduce their accumulation and to inhibit their translocation. Particularly, IONS-PG was completely excluded from worms of all developmental stages. By covalently introducing sulfate, carboxyl and amino groups onto IONS-PG, we further demonstrated that positively charged IONS-PG-NH3+ induced high intestinal accumulation, cuticle adhesion and distal translocation, whereas the negatively charged IONS-PG-OSO3– and IONS-PG-COO– were excreted out. Consequently, no apparent deleterious effects on brood size and life span were observed in worms treated by IONS-PG and IONS-PG bearing negatively charged groups. This study presents new surface functionalization approaches for developing ecofriendly nanomaterials.

A Short Appraisal of Magnetic Nanoparticles for Breast Cancer: In vitro and In vivo Research.

The increasing incidence of breast cancer and the associated morbidity due to higher metastasis created the urge to develop a nanocarrier that can be used as a potent therapeutic carrier with targeting efficacy. The use of superparamagnetic nanoparticles in breast cancer research and treatment has gained considerable attention in recent years. Magnetic nanoparticles (MNPs) can be used to construct nanocarriers since they possess superior properties such as superparamagnetism, easy surface functionalization to attach ligands, and non-immunogenic. MNPs are superior carriers that are used to target cancer cells without harming the normal cells in the body, which leads to therapeutic efficacy in the body. Along with their established anticancer potential and enhanced drug concentration at endosomal pH, the superparamagnetic property of MNPs was further exploited for their applications in reticuloendothelial uptake, drug delivery, medical imaging, and theranostics applications in breast cancer. Moreover, the clinical translational of MNPs, along with future prospects and key challenges in vivo, have been duly presented in the final review. The scientists preferred the ongoing research in MNPs due to their high biocompatibility and ease of targeting at molecular and cellular levels. The review highlighted the in vitro and in vivo research and patent supported data for potential use of MNPs for the treatment of breast cancer.

Multienzyme Mimicking Cascade Mn3O4 Catalyst to Augment Reactive Oxygen Species Elimination and Colorimetric Detection: A Study of Phase Variation upon Calcination Temperature.

Over decades, nanozyme has served as a better replacement of bioenzymes and fulfills most of the shortcomings and intrinsic disadvantages of bioenzymes. Recently, manganese-based nanomaterials have been highly noticed for redox-modulated multienzyme mimicking activity and wide applications in biosensing and biomedical science. The redox-modulated multienzyme mimicking activity was highly in tune with their size, surface functionalization, and charge on the surface and phases. On the subject of calcination temperature to Mn3O4 nanoparticles (NPs), its phase has been transformed to Mn2O3 NPs and Mn5O8 NPs upon different calcination temperatures. Assigning precise structure-property connections is made easier by preparing the various manganese oxides in a single step. The present study has focused on the variation of multienzyme mimicking activity with different phases of Mn3O4 NPs, so that they can be equipped for multifunctional activity with greater potential. Herein, spherical Mn3O4 NPs have been synthesized via a one-step coprecipitation method, and other phases are obtained by direct calcination. The calcination temperature varies to 100, 200, 400, and 600 °C and the corresponding manganese oxide NPs are named M-100, M-200, M-400, and M-600, respectively. The phase transformation and crystalline structure are evaluated by powder X-ray diffraction and selected-area electron diffraction analysis. The different surface morphologies are easily navigated by Fourier transform infrared, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy analysis. Fortunately, for the mixed valence state of Mn3O4 NPs, all phases of manganese oxide NPs showed multienzyme mimicking activity including superoxide dismutase (SOD), catalase, oxidase (OD), and peroxidase; therefore, it offers a synergistic antioxidant ability to overexpose reactive oxygen species. Mn3O4 NPs exhibited good SOD-like enzyme activity, which allowed it to effectively remove the active oxygen (O2•-) from cigarette smoke. A sensitive colorimetric sensor with a low detection limit and a promising linear range has been designed to detect two isomeric phenolic pollutants, hydroquinone (H2Q) and catechol (CA), by utilizing optimized OD activity. The current probe has outstanding sensitivity and selectivity as well as the ability to visually detect two isomers with the unaided eye.

Advanced Anti-Icing Strategies and Technologies by Macrostructured Photothermal Storage Superhydrophobic Surfaces.

Water is the source of life and civilization, but water icing causes catastrophic damage to human life and diverse industrial processes. Currently, superhydrophobic surfaces (inspired by the lotus effect) aided anti-icing attracts intensive attention due to their energy-free property. Here, recent advances in anti-icing by design and functionalization of superhydrophobic surfaces are reviewed. The mechanisms and advantages of conventional, macrostructured, and photothermal superhydrophobic surfaces are introduced in turn. Conventional superhydrophobic surfaces, as well as macrostructured ones, easily lose the icephobic property under extreme conditions, while photothermal superhydrophobic surfaces strongly rely on solar illumination. To address the above issues, a potentially smart strategy is found by developing macrostructured photothermal storage superhydrophobic (MPSS) surfaces, which integrate the functions of macrostructured superhydrophobic materials, photothermal materials, and phase change materials (PCMs), and are expected to achieve all-day anti-icing in various fields. Finally, the latest achievements in developing MPSS surfaces, showcasing their immense potential, are highlighted. Besides, the perspectives on the future development of MPSS surfaces are provided and the problems that need to be solved in their practical applications are proposed.

Universal Covalent Grafting Strategy of an Aptamer on a Carbon Fiber Microelectrode for Selective Determination of Dopamine In Vivo.

The chemical information on brain science provided by electrochemical sensors is critical for understanding brain chemistry during physiological and pathological processes. A major challenge is the selectivity of electrochemical sensors in vivo. This work developed a universal covalent grafting strategy of an aptamer on a carbon fiber microelectrode (CFE) for selective determination of dopamine in vivo. The universal strategy was proposed by oxidizing poly(tannic acid) (pTA) to form an oxidized state (pTAox) and then coupling a nucleophilic sulfhydryl molecule of the dopamine-binding mercapto-aptamer with the o-quinone moiety of pTAox based on click chemistry for the interfacial functionalization of the CFE surface. It was found that the universal strategy proposed could efficiently graft the aptamer on a glassy carbon electrode, which was verified by using electroactive 6-(ferrocenyl) hexanethiol as a redox reporter. The amperometric method using a fabricated aptasensor for the determination of dopamine was developed. The linear range of the aptasensor for the determination of dopamine was 0.2-20 μM with a sensitivity of 0.09 nA/μM and a limit of detection of 88 nM (S/N = 3). The developed method has high selectivity originating from the specific recognition of the aptamer in concert with the cation-selective action of pTA and could be easily applicable to probe dopamine dynamics in the brain. Furthermore, complex vesicle fusion modes were first observed at the animal level. This work demonstrated that the covalently grafted immobilization strategy proposed is promising and could be extended to the in vivo analysis of other neurochemicals.

Accelerating overall electrochemical water splitting at the heterogeneous interface of surface crystallized Chiral Amide-bonded CoIIporphyrins

Herein, a series of six chiral-amide bonded CoIIporphyrins containing L/D-alanine, phenylalanine and tryptophan were isolated and characterized. Interestingly, the surface crystallized CoIIporphyrins nanomaterials have the significant increase of the electrochemically catalyzed overall water splitting, and the tunable catalytic activities could be modulated by the enantiomeric isomers and the types of meso-substituted amino acids. Meanwhile, the surface crystallized CoIIporphyrins are stable in a wide range of medias which have provided the new insights of surface functionalization strategies towards enhanced overall water splitting.

Development of an Aptamer-Based QCM-D Biosensor for the Detection of Thrombin Using Supported Lipid Bilayers as Surface Functionalization

Development of an Aptamer-Based QCM-D Biosensor for the Detection of Thrombin Using Supported Lipid Bilayers as Surface Functionalization

Symmetry-Breaking of Nanoparticle Surface Function Via Conformal DNA Design.

Asymmetric surface functionalization of complex nanoparticles to control their directional self-assembly remains a considerable challenge. Here, we demonstrated a conformal DNA design strategy for flexible remodeling of the surface of complex nanoparticles, taking Au nanobipyramids (AuNBPs) as a model. We sheathed one or both tips of AuNBPs into conformal DNA origami with an exceptionally accurate orientation control. Such asymmetrically and symmetrically distributed surface patches possess regioselective, sequence, and site-specific DNA binding capabilities. As a result, we realized a series of prototypical multicomponent "colloidal molecules" made of AuNBPs and Au nanospheres (AuNSs) with defined directionality and number of "bonding valence" as well as 1D and 3D hierarchical assemblies, e.g., inverse core-satellites of AuNBPs and AuNSs, side-by-side and tip-to-tip linear assemblies of AuNBPs, and 3D helical superstructures of AuNBPs with tunable twists. These findings inspire new opportunities for nanoparticle surface engineering and the high-order self-assembly of nanoarchitectures with higher complexity and broadened functionalities.

Biologicals and Biomaterials for Corneal Regeneration and Vision Restoration in Limbal Stem Cell Deficiency.

The mammalian cornea is decorated with stem cells bestowed with the life-long task of renewing the epithelium, provided they remain healthy, functional and in sufficient numbers. If not, a debilitating disease known as limbal stem cell deficiency (LSCD) can develop causing blindness. Decades after the first stem cell (SC) therapy was devised to treat this condition, patients continue to suffer unacceptable failures. During this time, improvements to therapeutics have included identifying better markers to isolate robust SC populations and nurturing them on crudely modified biological or biomaterial scaffolds including human amniotic membrane, fibrin and contact lenses, prior to their delivery. Researchers are now gathering information about the biomolecular and biomechanical properties of the corneal SC niche to decipher what biological and/or synthetic materials can be incorporated into these carriers. Advances in biomedical engineering including electrospinning and 3D bioprinting with surface functionalization and micropatterning, and self-assembly models, have generated a wealth of biocompatible, biodegradable, integrating scaffolds to choose from, some of which are being tested for their SC delivery capacity in the hope of improving clinical outcomes for patients with LSCD. This article is protected by copyright. All rights reserved.

Effect of MWCNTs surface functionalization on the characterization of PVA/MWCNTs nanocomposites

Effect of MWCNTs surface functionalization on the characterization of PVA/MWCNTs nanocomposites

Silver and Copper Nanoparticle-Loaded Self-Assembled Pseudo-Peptide Thiourea-Based Organic-Inorganic Hybrid Gel with Antibacterial and Superhydrophobic Properties for Antifouling Surfaces.

The escalating threat of antimicrobial resistance has become a global health crisis. Therefore, there is a rising momentum in developing biomaterials with self-sanitizing capabilities and inherent antibacterial properties. Despite their promising antimicrobial properties, metal nanoparticles (MNPs) have several disadvantages, including increased toxicity as the particle size decreases, leading to oxidative stress and DNA damage that need consideration. One solution is surface functionalization with biocompatible organic ligands, which can improve nanoparticle dispersibility, reduce aggregation, and enable targeted delivery to microbial cells. The existing research predominantly concentrates on the advancement of peptide-based hydrogels for coating materials to prevent bacterial infection, with limited exploration of developing surface coatings using organogels. Herein, we have synthesized organogel-based coatings doped with MNPs that can offer superior hydrophobicity, oleophobicity, and high stability that are not easily achievable with hydrogels. The self-assembled gels displayed distinct morphologies, as revealed by scanning electron microscopy and atomic force microscopy. The cross-linked matrix helps in the controlled and sustained release of MNPs at the site of bacterial infection. The synthesized self-assembled gel@MNPs exhibited excellent antibacterial properties against harmful bacteria such as Escherichia coli and Staphylococcus aureus and reduced bacterial viability up to 95% within 4 h. Cytotoxicity testing against metazoan cells demonstrated that the gels doped with MNPs were nontoxic (IC50 > 100 μM) to mammalian cells. Furthermore, in this study, we coated the organogel@MNPs on cotton fabric and tested it against Gram +ve and Gram -ve bacteria. Additionally, the developed cotton fabric exhibited superhydrophobic properties and developed a barrier that limits the interaction between bacteria and the surface, making it difficult for bacteria to adhere and colonize, which holds potential as a valuable resource for self-cleaning coatings.

A facile strategy for tuning the density of surface-grafted biomolecules for melt extrusion-based additive manufacturing applications

AbstractMelt extrusion-based additive manufacturing (ME-AM) is a promising technique to fabricate porous scaffolds for tissue engineering applications. However, most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell fate. Grafting of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct; however, there are limited strategies available to control the surface density. Here, we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k (PCL5k) containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different ratios. Stable porous three-dimensional (3D) scaffolds were then fabricated using a high weight percentage (75 wt.%) of the low molecular weight PCL5k. As a proof-of-concept test, we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface, yielding a density of 201–561 pmol/cm2. Subsequently, a bone morphogenetic protein 2 (BMP-2)-derived peptide was grafted onto the films comprising different blend compositions, and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells (hMSCs) was assessed. After two weeks of culturing in a basic medium, cells expressed higher levels of BMP receptor II (BMPRII) on films with the conjugated peptide. In addition, we found that alkaline phosphatase activity was only significantly enhanced on films containing the highest peptide density (i.e., 561 pmol/cm2), indicating the importance of the surface density. Taken together, these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material interface. Moreover, we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of (modified) polymers. Furthermore, the use of alkyne–azide “click” chemistry enables spatial control over bioconjugation of many tissue-specific moieties, making this approach a versatile strategy for tissue engineering applications. Graphic abstract

Properties, Synthesis and Emerging Applications of Graphdiyne: A Journey Through Recent Advancements.

Graphdiyne (GDY) is a new variant of nano-carbon material with excellent chemical, physical and electronic properties. It has attracted wide attention from researchers and industrialists for its extensive role in the fields of optics, electronics, bio-medics and energy. The unique arrangement of sp-sp2 carbon atoms, linear acetylenic linkages, uniform pores and highly conjugated structure offer numerous potentials for further exploration of GDY materials. However, since the material is at its infancy, not much understanding is available regarding its properties, growth mechanism and future applications. Therefore, in this review, readers are guided through a brief discussion on GDY's properties, different synthesis procedures with a special focus on surface functionalization and a list of applications for GDY. The review also critically analyses the advantages and disadvantages of each synthesis route and emphasizes the future scope of the material.

Rapid Waste Motor Oil Conversion into Diesel-Range Hydrocarbons Using Hydrochar as Catalyst: Kinetic Study and Product Characterization

Herein, raw and alkali-treated hydrochars from biomass waste are prepared as a highly active catalyst for the conversion of waste motor oil into diesel-like fuels. Among all materials, hydrochar obtained at 250 °C and subsequent alkali activation with KOH showed a 600% improvement of the kinetic constant from 0.0088 to 0.0614 m−1. Conversion values at the same conditions were also improved from 66 to 80% regarding thermal and catalytic cracking, respectively. Moreover, the activation energy was also reduced from 293 to 246 kJ mol−1 for thermal and catalytic cracking, respectively. After characterization, the enhanced catalytic activity was correlated to an increased surface area and functionalization due to the alkali activation. Finally, the liquid product characterization demonstrated that catalytic cracking is more effective than thermal cracking for producing hydrocarbons in the diesel range. In particular, hydrochar-based catalysts are suggested to promote the formation of specific hydrocarbons so that the carbon distribution can be tailored by modifying the hydrothermal treatment temperature.

Hazard assessment of nanoplastics is driven by their surface-functionalization. Effects in human-derived primary endothelial cells

During plastic waste degradation into micro/nanoplastics (MNPLs) their physicochemical characteristics including surface properties (charge, functionalization, biocorona, etc.) can change, potentially affecting their biological effects. This paper focuses on the surface functionalization of MNPLs to determine if it has a direct impact on the toxicokinetic and toxicodynamic interactions in human umbilical vein endothelial cells (HUVECs), at different exposure times. Pristine polystyrene nanoplastics (PS-NPLs), as well as their carboxylated (PS-C-NPLs) and aminated (PS-A-NPLs) forms, all around 50 nm, were used in a wide battery of toxicological assays. These assays encompassed evaluations on cell viability, cell internalization, induction of intracellular reactive oxygen species (iROS), and genotoxicity. The experiments were conducted at a concentration of 100 μg/mL, chosen to ensure a high internalization rate across all treatments while maintaining a sub-toxic concentration. Our results show that all PS-NPLs are internalized by HUVECs, but the internalization dynamic depends on the particle's functionalization. PS-NPLs and PS-C-NPLs internalization modify the morphology of the cell increasing its inner complexity/granularity. Regarding cell toxicity, only PS-A-NPLs reduced cell viability. Intracellular ROS was induced by the three different PS-NPLs but at different time points. Genotoxic damage was induced by the three PS-NPLs at short exposures (2 h), but not for PS-C-NPLs at 24 h. Overall, this study suggests that the toxicological effects of PSNPLs on HUVEC cells are surface-dependent, highlighting the relevance of using human-derived primary cells as a target.

Enhancing Surface Morphology, Mechanical, and Wettability Properties of PVA/Chitosan/HAp Nanofiber Scaffold through Dielectric Barrier Discharge Plasma Treatment

Abstract Dielectric barrier discharge (DBD) plasma treatment has been widely used for surface functionalization, allowing for precise modification of surface chemistry and morphology. This study investigates the efficacy of DBD plasma treatment in enhancing the surface morphology and wettability of electrospun nanofiber scaffolds composed of polyvinyl alcohol (PVA), chitosan, and hydroxyapatite (HAp), with potential applications in bone tissue engineering. Scanning electron microscopy (SEM) revealed significant alterations in surface morphology after treatment, including a reduction in average fiber diameter and the presence of uneven, damaged, and even broken fibers. Interestingly, the ultimate strength of the nanofibers increased from 1.13 ± 0.05 MPa to 6.99 ± 0.07 MPa despite the decrease in diameter. Contact angle measurements confirmed a remarkable improvement in wettability, with the contact angle decreasing from 39.46° to 7.45° following increasing treatment time. This enhanced wettability suggests improved cell adhesion, potentially leading to more effective bone tissue regeneration.

Harmonising light and structure: exploring ZnO/MOF composite photocatalysts for environmental remediations

Harmonising light and structure: exploring ZnO/MOF composite photocatalysts for environmental remediations

Incorporating Fluorescent Organosilica and Zeolitic Imidazolate Frameworks into Periodic Mesoporous Organosilica for the Enhanced Cargo Delivery of 5‐Fluorouracil

AbstractNanosized zeolitic imidazolate frameworks (nZIFs) are being researched as 5‐fluorouracil (5‐FU) carriers for the treatment of cancer. The surface functionalization of ZIFs with periodic mesoporous organosilicas (PMOs) is expected to enhance stability and prevent the flocculation of nZIFs. In this study, ZIF‐7 nanomaterials and fluorescent organosilicas (FITC−APTES) were effectively introduced into PMO nanoparticles, and the resulting product was named ZIF‐7@PMO. The surface functionalization with the PMO nanoparticles enhanced the chemical stability of ZIF‐7 nanoparticles in ethanol. The study examined the impact of temperature on the synthesis of ZIF‐7@PMO and found that low temperatures were more conducive to the encapsulation of ZIF‐7 nanoparticles and fluorescent organosilica, as well as pore size retention. Moreover, the drug storage capacity of the ZIF‐7@PMO nanoparticles was evaluated via their loading and release of 5‐FU. The results revealed that the ZIF‐7@PMO nanoparticles could adsorb 5‐FU with a loading capacity of 100–140 mg g−1 for 24 h. ZIF‐7@PMO released half of 5‐FU amount within 8 h before releasing a maximum of 75 % within 3 days. Therefore, the fluorescent ZIF‐7@PMO nanoparticles could be a potential drug carrier in the field of controlled drug delivery.

Nanotechnology in the Fabrication of Advanced Paints and Coatings: Dispersion and Stabilization Mechanisms for Enhanced Performance

AbstractThis review comprehensively analyzes the challenge of dispersing and stabilizing of various common nanomaterials (NMs), including TiO₂, SiO₂, Ag, ZnO, graphene, carbon nanotubes (CNTs) and some others, in paints and coatings. It delves into the critical factors influencing dispersion, such as nanoparticle size, shape, concentration, and their distribution within the coating matrix.The review encompasses all stages of dispersion methods, including wetting, separation techniques, and stabilization. Regarding stabilization, both chemical and physical stabilization methods are discussed, along with their mechanisms, involving surface modification or functionalization of NMs, particularly tailored for aqueous and solvent‐based coatings and common resins (Acrylic, Urethane, Epoxy, Alkyd, etc.). Furthermore, common blending methods to fabricate uniform paints, coatings, and nanocomposites (NCPs) are examined. By providing a comprehensive understanding of the mechanisms governing NM dispersion and stabilization, this review facilitates the selection of appropriate surface modifications based on the specific resins or solvents, thereby enabling the fabrication of high‐performance paints and coatings. In summary, this review elucidates the essence of addressing the challenges associated with NM dispersion and stabilization, outlines methodologies employed, discusses findings regarding their effects on coating properties, and recommends tailored approaches for fabricating high‐performance paints and coatings.

Enhancing the Storage Stability and Rutting Resistance of Modified Asphalt through Surface Functionalization of Waste Tire Rubber Powder

Waste tire rubber powder-modified asphalt (RMA) has been widely used in road construction, which was traditionally limited by the poor compatibility of RMA, affecting pavement performance. By synthesizing epoxy soybean oil with amide groups (ESO/TETA) and grafting it onto desulfurized rubber powder (DCR) through microwave irradiation, a surface-functionalized rubber powder (MDCR) was produced successfully. The effects of the physical properties, storage stability, thermal stability, and rheological behavior of the modified asphalt were studied. The results show that the MDCR with a polar surface improved the compatibility and adhesive interactions between the modified crumb rubber and the asphalt. The MDCR content could reach 50%, and the phase separation could meet the requirements of 2.2 °C, which has application conditions in engineering for stable storage. Additionally, the inclusion of MDCR in the asphalt formulations significantly mitigated the temperature sensitivity of the modified asphalt. Importantly, when the MDCR constituted from 20% to 50% of the asphalt, there was a noted reduction in the phase angle at temperatures above 70 °C, indicating a significant improvement in the elastic efficiency. The MDCR also led to substantial enhancements in the resistance of the asphalt to high-temperature and high-stress rutting, addressing the crucial limitations in the consumption ability of waste tire rubber powder and improving the overall performance of RMA in pavement applications.