Surface Functionalization Research Articles

Clickable Plastic Surfaces with Controllable Azide Surface Density

AbstractThis study investigates the surface functionalization of plastic substrates through dip‐coating in azide‐functionalized polymer solutions, followed by a click reaction (i.e., strain‐promoted azide–alkyne cycloaddition). Acrylic, poly(ethylene terephthalate) (PET), and nylon substrates are dip‐coated with a series of polymers containing various azide groups grafted onto the poly(methyl methacrylate‐co‐hydroxyethyl methacrylate) backbone to examine structural effects on the surface density of clickable azide groups. X‐ray photoelectron spectroscopy and fluorescence spectroscopy confirm the subsequent click‐immobilization of cycloalkyne‐tagged fluorescein, which is quantified to calculate the surface density of clickable azide groups. Further investigations demonstrate that the surface density of azide groups can be controlled by manipulating the polymer ratio during dip‐coating, thus enabling the preparation of a linear surface gradient in terms of azide group density. Finally, the microcontact printing (µCP) method is employed to pattern the functionalized surfaces and quantify the functional molecules immobilized on the surface by µCP. This study highlights the adaptability of click chemistry and polymer coating techniques for the advanced functionalization of plastic surfaces for materials science and engineering applications.

Harnessing visible light for sustainable biodiesel production with Ni/Si/MgO photocatalyst

Sustainable energy sources frequently demonstrate greater reliability and resilience in comparison to conventional energy sources. Biodiesel, with its markedly reduced carbon footprint when compared to petroleum-based diesel fuel, owes this advantage to its production from renewable resources. Heterojunction photocatalysts have gained significant interest due to their immense promise in tackling environmental challenges. In this study, a highly efficient photocatalyst, Ni/Si/MgO, for biodiesel production under visible light irradiation was synthesized using a solid-phase reaction method with silica as the silicon source, along with Ni and MgO. The surface functionality of Ni/Si/MgO was crucial for achieving high efficiency of photocatalytic systems, as evident from XPS. The transesterification reaction on the Ni/Si/MgO photocatalyst proceeds by the formation of SiH and SiOH bonds over the catalyst. The photocatalytic activities of Ni/Si/MgO photocatalysts were higher than those of the Si/MgO nanoparticle when exposed to light. Achieving an optimal yield of 98 %, the biodiesel production was carried out under the following reaction conditions: A catalyst dosage of 2 % by weight was utilized, along with a methanol-to-oil molar ratio of 12:1, and the entire procedure was executed within a duration of 3.5 h. Plasmonic near-fields are speculated to be responsible for the increased transesterification activity along the Ni/Si/MgO interface. In order to carry out the transesterification reaction, electron-hole pairs are generated along the Ni/Si/MgO interface, where plasmonic near-fields are highly concentrated. This study contributes a significant perspective on mechanisms governing the process of efficient plasmonic photocatalysis responsive to visible light. These findings hold the potential to offer valuable guidance in the formulation and design of next-generation, high-performance photocatalysts.

Iron oxide nanoparticles synthesized by coprecipitation method: Impacts of zinc doping and surface functionalization by polyvinylpyrrolidone on the magnetic properties and heating efficiency

Iron oxide nanoparticles synthesized by coprecipitation method: Impacts of zinc doping and surface functionalization by polyvinylpyrrolidone on the magnetic properties and heating efficiency

Deferoxamine functionalized alginate-based collagen composite material enhances the integration of metal implant and bone interface

Poor osseointegration markedly compromises the longevity of prostheses. To enhance the stability of titanium implants, surface functionalization is a proven strategy to promote prosthesis-bone integration. This study developed a hydrogel coating capable of simultaneous osteoangiogenesis and vascularization by incorporating deferoxamine (DFO) into a sodium alginate mineralized collagen composite hydrogel. The physicochemical properties of this hydrogel were thoroughly analyzed. In vivo and in vitro experiments confirmed the hydrogel scaffold's osteogenic and angiogenic capabilities. Results indicated that sodium alginate notably enhanced the mechanical characteristics of the mineralized collagen, allowing it to fully infiltrate the interstices of the 3D-printed titanium scaffold. Furthermore, as the hydrogel degraded, collagen, calcium ion, phosphate ion, and DFO were gradually released around the scaffolds, altering the local osteogenic microenvironment and strongly inducing new bone tissue growth. These findings offer novel perspectives for the creation and utilization of functionalized bone implant materials.

Simultaneous Optimization Approach for UV-C Radiator to Enhance Mechanical Properties of Semi-Finished Potato Tuber (Innovator) for Extended Storage Period

The efficacy of surface treatment technology is highly dependent on the dimensional and operational parameters. UV-C as a commonly used surface treatment technology required fine-tuning to achieve maximum storability of semi-finished products. This study therefore applied a simultaneous optimization approach for the multi-objective function to obtain the best possible combination of variables in the irradiation process (dose (15-45mJ/cm2, storage period (3-9d), and distance from the light (40-80cm)) that offer maintained properties of semi-finished potato tuber for extended storage life. The optimum values are obtained at the ~40.5mJ/cm2, 7 days, and 48cm granting a 756N, 6.7N, and 9N for compressive, bending, and cutting force resistance, respectively. Further insight into the surface functionality was studied using FT-IR and SEM analysis as a result similar spectral makeup was noted but a shift of absorption peak was observed in the irradiated sample at 30 and 45mJ/cm2. Also, a similar granular structure was observed from the morphologies.

Exploring effects of plasma surface engineering on cellulose nanofilms via broadband THz spectroscopy

For the extended ultra-wideband THz band up to 10 THz and beyond, materials with different functional properties are required. In addition, the THz shielding devices require the desired thickness for different shielding effects, which can be tailored by the surface functionalities. Here, a plasma-assisted soft chemistry approach was used to tailor the cellulose nanofibrils (CNFs), and the effects of plasma surface treatment were investigated using non-destructive terahertz time-domain spectroscopy (THz-TDS). CNFs with three different thicknesses were investigated as a function of mild and strong plasma treatment. The ultra-broadband THz-TDS evaluation of CNF films overcomes the challenge by surpassing the conventional low-frequency THz-TDS measurements and reveals many characteristic THz features of CNF at 2.1, 3.1, 5.1, 7.0, 10.3 and 10.9 THz. THz-TDS analysis indicates thinning of CNF after plasma treatment due to the plasma etching effect. At the same time, the microcrystalline properties of the CNF samples remain intact even after significant surface modification under plasma carbonisation conditions. Apart from this, the studies proposed the required minimum thickness for THz shielding applications based on the optical parameters and THz properties derived from the plasma-treated CNF structures, which could be used to define the thickness of sustainable shielding materials for THz devices.

Macrophage membrane-mediated targeted curcumin biomimetic nanoparticles delivery for diagnosis and treatment of spinal cord injury by suppressing neuroinflammation and ferroptosis

Spinal cord injury (SCI) is a severe and debilitating central nervous system disorder characterized by permanent motor and sensory deficits, with limited effective treatment options available. Recent advancements have been made in the functionalization of biomimetic surfaces of nanoparticles through the incorporation of synthetic bionic and naturally derived cell membranes. One emerging strategy involves integrating biomimetic features into therapeutic agents to achieve low immunogenicity, high targeting specificity, and prolonged drug half-life. In this study, we detail the preparation of nanoparticles via the self-assembly of the amphiphilic diblock copolymer PEG-b-PHPMA with curcumin and PCPDTBT in water, followed by macrophage cell membrane coating using an extrusion method, resulting in the formation of stable curcumin-loaded nanoparticles coated with cell membrane (MM@Cur). Our experimental results demonstrate that MM@Cur treatment specifically targets the SCI site, effectively mitigates ferroptosis and central inflammation in a mouse model featuring spinal cord contusion, and enhances the recovery of the motor function of hind limbs post-SCI. Therefore, our findings highlight MM@Cur as a highly targeted biomimetic nanoparticle possessing potent anti-ferroptosis and anti-inflammatory properties, offering a promising therapeutic approach for the restoration of hind limb function post-spinal cord injury

Surface Functionalization of WS2 nanosheets with Poly(N-vinylcaprolactam) and vinylacetic acid for targeted drug release in prostate cancer

Stimuli-responsive nanocarriers have gained attention in cancer therapy as a promising strategy because of their ability to enhance treatment efficacy and minimize off-target medication effects. This study introduces a novel nanopolymer responsive to pH and near-infrared (NIR) light as an intelligent carrier for delivering bicalutamide (BCT) into cancer cells. For this, the surface of tungsten disulfide (WS2) nanosheets is modified with temperature-responsive (poly(N-vinylcaprolactam)) and pH-sensitive (vinylacetic acid) polymers and then characterized using TGA, FE-SEM, XRD, and FT-IR techniques. Experimental variables including pH (5.56), temperature (25 °C), and contact time (11.02 min) are optimized using response surface methodology (RSM) and central composite design (CCD), yielding an adsorption efficacy of 99.45 %. The RSM-CCD model’s capability is analyzed using the correlation coefficient (R2) and several statistical error functions, including average relative error (ARE), root mean square error (RMSE), hybrid fractional error function (HYBRID), and Chi-square test (χ2). The in vitro drug release procedure is evaluated at different pH levels (5.6 and 7.4) and temperatures (37 and 50 °C). The results showed a maximum BCT release of 87.2 % within 6 h at 50 °C and pH 5.6, compared to 13.3 % at 37 °C and pH 7.4. Moreover, the BCT-loaded carrier demonstrates complete BCT release (100 %) following 10 min of NIR irradiation at pH 5.6. The kinetic data confirm that the best fit belongs to the zero-order model, and the drug release followed the supercase II transport mechanism.

Scalable and efficient fabrication of surface microstructures using a small wheeled robot with a vibration-cutting tool

Bioinspired microstructure emerges as a powerful technique to enhance the surface functionalities and properties in a seizes of breakthrough areas. However, its application is limited by the scalability of fabrication methods. This study introduces a scalable fabrication technique utilizing a small wheeled robot designed to operate on a workpiece surface. Due to its unique three-point-support design, the robot maintains a stable cutting depth and exhibits high adaptability to large-scale workpieces. Motion stability is calibrated using a laser displacement sensor, achieving a maximum velocity of approximately 3.7 mm/s. Finally, the robot successfully produces microstructures with a height of 8 μm on aluminum workpieces, demonstrating its promising capacity.

Electroactive covalent linkers for enhancing conducting polymer adhesion, charge transfer, and biological integration of PEDOT-coated carbon microfibers

Poly(3,4-ethylenedioxythiophene) (PEDOT)-coated carbon microfibers (PCMFs) are a key technology for developing advanced neuroprosthetic electrodes and electroactive tissue scaffolds. However, for their successful application in human therapeutics, PEDOT adhesion to the carbon substrate must be enhanced without compromising electric charge transfer. Here, electrically functional linkers are synthesized to modify the surface at the nanoscale, facilitating the covalent bonding of EDOT to carbon. The properties of the resulting microfibers are compared before and after PEDOT polymerization. PCMFs deterioration is studied by applying controlled mechanical stress in vitro or by implanting them in the rodent spinal cord in vivo. Amino phenyl-EDOT derivatives allow for efficient covalent carbon surface functionalization and PEDOT electropolymerization but substantially reduce charge transfer as assessed by chronopotentiometry, electrochemical impedance spectroscopy, and cyclic voltammetry. Nevertheless, the azido-EDOT (EDOT-Ph-N3) derivative is similarly effective for carbon surface modification, enabling PEDOT polymerization to develop a nanostructured CMF surface based on robust covalent bonds, and enhancing both electric charge transfer and PEDOT adhesion to the carbon substrate. This makes PCMFs more resistant to polymer delamination when assessed in vitro or when implanted into the neural tissue. Azido-EDOT modified PCMFs also show excellent biological integration within the spinal cord, causing negligible tissue damage and cell reactivity. Overall, azido-EDOT provides a superior electroconducting linker for anchoring PEDOT and optimizes the electrical, mechanical, and biological performance of PCMFs.

Effect of Medium-Chain-Length Alkyl Silane Modified Nanocellulose in Poly(3-hydroxybutyrate) Nanocomposites.

Poly (3-hydroxybutyrate) (PHB) is a valuable biopolymer that is produced in industrial quantity but is not widely used in applications due to some drawbacks. The addition of cellulose nanofibers (CNF) as a biofiller in PHB/CNF nanocomposites may improve PHB properties and enlarge its application field. In this work, n-octyltriethoxy silane (OTES), a medium-chain-length alkyl silane, was used to surface chemically modify the CNF (CNF_OTES) to enhance their hydrophobicity and improve their compatibility with PHB. The surface functionalization of CNF and nanodimension were emphasized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, atomic force microscopy, dynamic light scattering, and water contact angle (CA). Surface modification of CNF with OTES led to an increase in thermal stability by 25 °C and more than the doubling of CA. As a result of the higher surface hydrophobicity, the CNF_OTES were more homogeneously dispersed in PHB than unmodified CNF, leading to a PHB nanocomposite with better thermal and mechanical properties. Thus, an increase by 122% of the storage modulus at 25 °C, a slight increase in crystallinity, a better melting processability, and good thermal stability were obtained after reinforcing PHB with CNF_OTES, paving the way for increasing PHB applicability.

Enhancing Antibacterial Properties of Titanium Implants through Covalent Conjugation of Self-Assembling Fmoc-Phe-Phe Dipeptide on Titania Nanotubes.

Bacterial infections and biofilm formation are significant challenges for medical implants. While titanium nanotube engineering improves biocompatibility, it cannot prevent bacterial adhesion and biofilm formation. Optimizing the biomaterial's surface chemistry is vital for its desired functioning in the biological environment. This study demonstrates the covalent conjugating of the self-assembling dipeptide N-fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF) onto titanium nanotube surfaces (TiNTs) without altering the topography. Fmoc-FF peptides, in conjugation with TiNTs, can inhibit biofilm formation, eradicate pre-existing biofilms, and kill bacteria. This functionalization imparts antibacterial properties to the surface while retaining beneficial nanotube topography, synergistically enhancing bioactivity. Surface characterization by XPS, FT-IR, EDS, and SEM confirmed the successful functionalization. Bacterial adhesion experiments showed a significantly improved antibacterial activity of the functionalized TiNT surfaces. This study opens future possibilities for associating biomedical applications such as cell-cell interactions, tissue engineering, and controlled drug delivery of multifunctional self-assembling short peptides with implant materials through surface functionalization.

The Dawning Era of Anticancer Nanomedicines: From First Principles to Application of Silk Nanoparticles

AbstractThis review introduces nanomedicines and medical silks by addressing seminal and recent research within these fields. First, the successes of nanoparticles in improving the safety profiles and pharmacokinetic–pharmacodynamic properties are explored but also the concepts of threshold dosing and targeting of tumor‐associated macrophages. Current barriers to systemic delivery of nanomedicines are detailed and methods to overcome these barriers and increase tumor targeting are evaluated, namely: tuning the nanomedicine size and surface charge for enhanced tumor accumulation and penetration; non‐spherical nanomedicine morphologies for macrophage evasion and targeted delivery to endothelial cells; and, surface functionalization for stealth coatings and targeting receptor‐mediated endocytosis. The advantages of using silk as a nanomedicine with reference to its structure, composition, biological performance, and formulation are discussed. While batch methods for silk processing enable the formation of nano to microparticles, continuous technology can overcome bottlenecks of the deployed engineering methods such as low throughput and poor reproducibility. Finally, the chemical modification of silk using homogeneous and heterogenous chemistries is assessed within the nanomedicine context. Overall, this review covers silk nanomedicines from first principles to carrier design and on to areas of future development.

Synergistic Integration of Carbon Quantum Dots in Biopolymer Matrices: An Overview of Current Advancements in Antioxidant and Antimicrobial Active Packaging.

Approximately one-third of the world's food production, i.e., 1.43 billion tons, is wasted annually, resulting in economic losses of nearly USD 940 billion and undermining food system sustainability. This waste depletes resources, contributes to greenhouse gas emissions, and negatively affects food security and prices. Although traditional packaging preserves food quality, it cannot satisfy the demands of extended shelf life, safety, and sustainability. Consequently, active packaging using biopolymer matrices containing antioxidants and antimicrobials is a promising solution. This review examines the current advancements in the integration of carbon quantum dots (CQDs) into biopolymer-based active packaging, focusing on their antioxidant and antimicrobial properties. CQDs provide unique advantages over traditional nanoparticles and natural compounds, including high biocompatibility, tunable surface functionality, and environmental sustainability. This review explores the mechanisms through which CQDs impart antioxidant and antimicrobial activities, their synthesis methods, and their functionalization to optimize the efficacy of biopolymer matrices. Recent studies have highlighted that CQD-enhanced biopolymers maintain biodegradability with enhanced antioxidant and antimicrobial functions. Additionally, potential challenges, such as toxicity, regulatory considerations, and scalability are discussed, offering insights into future research directions and industrial applications. This review demonstrates the potential of CQD-incorporated biopolymer matrices to transform active packaging, aligning with sustainability goals and advancing food preservation technologies.

Interaction of graphene oxide with tannic acid: computational modeling and toxicity mitigation in C. elegans.

Graphene oxide (GO) undergoes multiple transformations when introduced to biological and environmental media. GO surface favors the adsorption of biomolecules through different types of interaction mechanisms, modulating the biological effects of the material. In this study, we investigated the interaction of GO with tannic acid (TA) and its consequences for GO toxicity. We focused on understanding how TA interacts with GO, its impact on the material surface chemistry, colloidal stability, as well as, toxicity and biodistribution using the Caenorhabditis elegans model. Employing computational modeling, including reactive classical molecular dynamics and ab initio calculations, we reveal that TA preferentially binds to the most reactive sites on GO surfaces via the oxygen-containing groups or the carbon matrix; van der Waals interaction forces dominate the binding energy. TA exhibits a dose-dependent mitigating effect on the toxicity of GO, which can be attributed not only to the surface interactions between the molecule and the material but also to the inherent biological properties of TA in C. elegans. Our findings contribute to a deeper understanding of GO's environmental behavior and toxicity and highlight the potential of tannic acid for the synthesis and surface functionalization of graphene-based nanomaterials, offering insights into safer nanotechnology development.

It's not just a phase: shaping the future of 3D photoprinted polymers with polymerization‐induced phase separation

AbstractAdditive manufacturing is a technology that promises to disrupt the conventional manufacturing industry due to its ability to create complex structures with improved macroscopic control not available with existing techniques like molding or milling. In addition to superior macroscopic structural control, photoprinting methods such as digital light projection can enable molecular‐scale control over the fabrication process by taking advantage of the self‐sorting or assembly properties of the monomers themselves. Polymerization‐induced phase separation (PIPS) allows for the remarkable introduction of microscopic control into additive manufacturing, using polymer‐rich and polymer‐poor regions that rely on incompatibilities to phase separate during polymerization creating new complex materials not achieved by traditional methods. With the incorporation of porogens or filler materials, microporosity and/or surface functionalization can be introduced in a facile one‐step printing process. This expands the potential applications of 3D printed materials, to include micro‐ and macroscale structural control. Using PIPS as a design strategy, polymeric materials with previously unprecedented capabilities can be produced with ease enabling 3D printing to grow into its full potential as a manufacturing tool. © 2024 Society of Chemical Industry.

Versatility of the Templated Surface Assembly of Nanoparticles from Water-in-Oil Microemulsions in Equivalent Hybrid Nanostructured Films.

Water-in-oil microemulsions, as stable colloidal dispersions from quasi-ternary mixtures, have been used in diverse applications, including nanoreactors for confined chemical processes. Their use as soft templates not only includes nanomaterial synthesis but also the interfacial assembly of nanoparticles in hybrid nanostructures. Especially the hierarchical arrangement of different types of nanoparticles over a surface in filament networks constitutes an interesting bottom-up strategy for facile and tunable film coating. Herein, we demonstrate the versatility of this surface assembly from microemulsion dispersions. Transmission and Scanning Electron Microscopy, in addition to UV-Vis Transmittance Spectroscopy, proved the assembly tunability after solvent evaporation under different conditions: the nanostructured films can be formed over different surfaces, using different compositions of liquid phases, as well as with the incorporation of different nanoparticle materials while keeping equivalent surface functionalization. This offers the possibility of adapting different components and conditions for coating tuning on a larger scale with simple procedures.

Carbon nanomaterials for efficient oxygen and hydrogen evolution reactions in water splitting: A review

Water splitting has gained significant attention as a means to produce clean and sustainable hydrogen fuel through the electrochemical or photoelectrochemical decomposition of water. Efficient and cost-effective water splitting requires the development of highly active and stable catalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Carbon nanomaterials, including carbon nanotubes, graphene, and carbon nanofibers, etc., have emerged as promising candidates for catalyzing these reactions due to their unique properties, such as high surface area, excellent electrical conductivity, and chemical stability. This review article provides an overview of recent advancements in the utilization of carbon nanomaterials as catalysts or catalyst supports for the OER and HER in water splitting. It discusses various strategies employed to enhance the catalytic activity and stability of carbon nanomaterials, such as surface functionalization, hybridization with other active materials, and optimization of nanostructure and morphology. The influence of carbon nanomaterial properties, such as defect density, doping, and surface chemistry, on electrochemical performance is also explored. Furthermore, the article highlights the challenges and opportunities in the field, including scalability, long-term stability, and integration of carbon nanomaterials into practical water splitting devices. Overall, carbon nanomaterials show great potential for advancing the field of water splitting and enabling the realization of efficient and sustainable hydrogen production.

Electrochemical Oxidation of Glyphosate Using Graphite Rod Electrodes: Impact of Acetic Acid Pretreatment on Degradation Efficiency

The uncontrolled use of herbicides such as glyphosate (GLY) (N-phosphonomethylglycine) in agricultural production has resulted in its presence in water bodies and in negative impacts on the environment and public health. On the frame of understanding the interaction between GLY and graphite rod surfaces, this contribution relies on the study of electrochemical responses of different GLY concentrations by cyclic voltammetry under both open and closed-circuit conditions. Furthermore, the effect of the electrodes’ electrochemical pretreatment with acetic acid on the double-layer capacitance and the subsequent surface functionalization of the graphite rod materials were evaluated. The increment in GLY concentration showed a decrease in the electrochemical oxidation response associated with the adsorption of the contaminant on the surface of the graphite rod electrode and the concomitant blockage of the active sites. Electrochemical pretreatment of the electrodes with acetic acid and GLY concentration play crucial roles in electric double-layer formation due to their ability to interact with both positive and negative electrical charges. By means of optical microscope observations and Fourier Transform Infrared Spectroscopy analysis, it was possible to detect the formation of oxygenated functional groups on the electrode surfaces after the electrochemical pretreatment. Through a 23 factorial design analysis in repetition, the factors significant in the degradation of GLY were identified. The high degradation of GLY with the pretreated electrodes can be attributed to the preferential adsorption of the zwitterionic molecule at the interface, which allowed great direct oxidation of the contaminant on the anode’s surface.

Synthesis, characterisation and functionalization of Hercynite nanoparticles for improved antibacterial activity

Hercynite i.e.,FeAl2O4 is an earth-abundant spinel mineral with a cubic crystal structure and belongs to the normal spinel ferrites possessing optical absorption in the visible range as well as superior magnetic and thermal properties. Herein, we synthesized nanosized FeAl2O4 where the citric acid-mediated sol–gel auto-combustion method was employed to achieve its pure phase and studied its physicochemical properties. Furthermore, the superior colloidal dispersion stability of the FeAl2O4 nanoparticles was achieved required for antibacterial activity and standardised via post-synthesis surface functionalisation using amino-propyl-triethoxysilane (APTES). We further characterised the material using states of art characterisation techniques for their structural, morphological, optical and thermal properties. Finally, the antibacterial activity of pure and surface functionalised FeAl2O4 nanoparticles was investigated against the Escherichia coli (E. coli) strain. We observed good penetration of surface functionalised FeAl2O4 nanoparticles into the bacterial membranes due to the high degree of dispersion achieved via cationic surface charge. Conclusively, a key finding of this study is the enhanced antibacterial properties of surface functionalised FeAl2O4 nanoparticles for the concentration of 31 µg/mL compared to pure FeAl2O4 nanoparticles at 62 µg/mL. This study has great relevance in the area of wound healing and tissue regeneration in the future.