Recent advances in chemical surface modification of metal oxide nanoparticles with silane coupling agents: A review

Biomolecule-grafted GO enhanced the mechanical and biological properties of 3D printed PLA scaffolds with TPMS porous structure

Graphene oxide (GO) exhibits excellent mechanical strength and modulus. However, its effectiveness in mechanically reinforcing polymer materials is limited due to issues with interfacial bonding and dispersion arising from differences in the physicochemical properties between GO and polymers. Surface modification using coupling agents is an effective method to improve the bonding problem between polymer and GO, but there may be biocompatibility issues when used in the biomedical field. In this study, the biomolecule L-lysine, was applied to improve the interfacial bonding and dispersion of GO in polylactic acid (PLA) without compromising biocompatibility. The PLA/L-lysine-modified GO (PLA/L-GO) bone scaffold with triply periodic minimal surface (TPMS) structure was prepared using fused deposition modeling (FDM). The FTIR results revealed successful grafting of L-lysine onto GO through the reaction between their -COOH and -NH2 groups. The macroscopic and microscopic morphology characterization indicated that the PLA/L-GO scaffolds exhibited an characteristics of dynamic diameter changes, with good interlayer bonding. It was noteworthy that the L-lysine modification promoted the dispersion of GO and the interfacial bonding with the PLA matrix, as characterized by SEM. As a result, the PLA/0.1L-GO scaffold exhibited higher compressive strength (13.2 MPa) and elastic modulus (226.8 MPa) than PLA/0.1GO. Moreover, PLA/L-GO composite scaffold exhibited superior biomineralization capacity and cell response compared to PLA/GO. In summary, L-lysine not only improved the dispersion and interfacial bonding of GO with PLA, enhancing the mechanical properties, but also improved the biological properties. This study suggests that biomolecules like L-lysine may replace traditional modifiers as an innovative bio-modifier to improve the performance of polymer/inorganic composite biomaterials.

Designing SERS nanotags for profiling overexpressed surface markers on single cancer cells: A review

This review focuses on the chemical design and the use of Surface-Enhanced Raman Scattering (SERS)-active nanotags for measuring surface markers that can be overexpressed at the surface of single cancer cells. Indeed, providing analytical tools with true single-cell measurements capabilities is capital, especially since cancer research is increasingly leaning toward single-cell analysis, either to guide treatment decisions or to understand complex tumor behaviour including the single-cell heterogeneity and the appearance of treatment resistance. Over the past two decades, SERS nanotags have triggered significant interest in the scientific community owing their advantages over fluorescent tags, mainly because SERS nanotags resist photobleaching and exhibit sharper signal bands, which reduces possible spectral overlap and enables the discrimination between the SERS signals and the autofluorescence background from the sample itself. The extensive efforts invested in harnessing SERS nanotags for biomedical purposes, particularly in cancer research, highlight their potential as the next generation of optical labels for single-cell studies. The review unfolds in two main parts. The first part focuses on the structure of SERS nanotags, detailing their chemical composition and the role of each building block of the tags. The second part explores applications in measuring overexpressed surface markers on single-cells. The latter encompasses studies using single nanotags, multiplexed measurements, quantitative information extraction, monitoring treatment responses, and integrating phenotype measurements with SERS nanotags on single cells isolated from complex biological matrices. This comprehensive review anticipates SERS nanotags to persist as a pivotal technology in advancing single-cell analytical methods, particularly in the context of cancer research and personalized medicine.

Recent Advances in Photodynamic Therapy: Metal-Based Nanoparticles as Tools to Improve Cancer Therapy

Cancer remains a significant global health challenge, with traditional therapies like surgery, chemotherapy, and radiation often accompanied by systemic toxicity and damage to healthy tissues. Despite progress in treatment, these approaches have limitations such as non-specific targeting, systemic toxicity, and resistance development in cancer cells. In recent years, nanotechnology has emerged as a revolutionary frontier in cancer therapy, offering potential solutions to these challenges. Nanoparticles, due to their unique physical and chemical properties, can carry therapeutic payloads, navigate biological barriers, and selectively target cancer cells. Metal-based nanoparticles, in particular, offer unique properties suitable for various therapeutic applications. Recent advancements have focused on the integration of metal-based nanoparticles to enhance the efficacy and precision of photodynamic therapy. Integrating nanotechnology into cancer therapy represents a paradigm shift, enabling the development of strategies with enhanced specificity and reduced off-target effects. This review aims to provide a comprehensive understanding of the pivotal role of metal-based nanoparticles in photodynamic therapy. We explore the mechanisms, biocompatibility, and applications of metal-based nanoparticles in photodynamic therapy, highlighting the challenges and the limitations in their use, as well as the combining of metal-based nanoparticles/photodynamic therapy with other strategies as a synergistic therapeutic approach for cancer treatment.

Ultrasound-Based Micro-/Nanosystems for Biomedical Applications

Due to the intrinsic non-invasive nature, cost-effectiveness, high safety, and real-time capabilities, besides diagnostic imaging, ultrasound as a typical mechanical wave has been extensively developed as a physical tool for versatile biomedical applications. Especially, the prosperity of nanotechnology and nanomedicine invigorates the landscape of ultrasound-based medicine. The unprecedented surge in research enthusiasm and dedicated efforts have led to a mass of multifunctional micro-/nanosystems being applied in ultrasound biomedicine, facilitating precise diagnosis, effective treatment, and personalized theranostics. The effective deployment of versatile ultrasound-based micro-/nanosystems in biomedical applications is rooted in a profound understanding of the relationship among composition, structure, property, bioactivity, application, and performance. In this comprehensive review, we elaborate on the general principles regarding the design, synthesis, functionalization, and optimization of ultrasound-based micro-/nanosystems for abundant biomedical applications. In particular, recent advancements in ultrasound-based micro-/nanosystems for diagnostic imaging are meticulously summarized. Furthermore, we systematically elucidate state-of-the-art studies concerning recent progress in ultrasound-based micro-/nanosystems for therapeutic applications targeting various pathological abnormalities including cancer, bacterial infection, brain diseases, cardiovascular diseases, and metabolic diseases. Finally, we conclude and provide an outlook on this research field with an in-depth discussion of the challenges faced and future developments for further extensive clinical translation and application.

Anticorrosion Performance of Waterborne Coatings with Modified Nanoscale Titania under Subtropical Maritime Climate

Steel structures located in subtropical marine climates face harsh conditions such as strong sunlight and heavy rain, and they are extremely corroded. In this study, a waterborne coating with excellent corrosion resistance, hydrophobic ability, high-temperature resistance and high density was successfully prepared by using modified nanoscale titania powders and grafted polymers. The effects of three modifiers on titania nanoparticles and waterborne coatings' properties were studied independently. The experimental results showed that the activation index of the modification employing methacryloxy silane reached 97.5%, which achieved the best modification effect at 64.4 °C for 43.3 min. The waterborne coating with nanoscale titania modified by methacryloxy silane exhibited the best hydrophobic effect, with a drop contact angle of 115.4° and excellent heat resistance of up to 317.2 °C. The application of the waterborne modified coating in steel structures under subtropical maritime climates showed that the waterborne titania coatings demonstrated excellent resistance to corrosion, high temperatures and harsh sunlight, with a maximum service life of up to five years. Economic analysis indicated that, considering a conservative three-year effective lifespan, this coating could save more than 50% in cost compared with conventional industrial coatings. Finally, the strengthening mechanism of the polymer coatings with modified nanoscale titania was analyzed.

Low-salinity water flooding by a novel hybrid of nano γ-Al2O3/SiO2 modified with a green surfactant for enhanced oil recovery

This paper introduces a hybrid enhanced oil recovery (HEOR) method that combines a low-salinity water flooding (LSWF) and nanoparticles (NPs) stabilized with a green surfactant. We experimentally investigated the use of combinations of silica (SiO2) and gamma alumina (γ-Al2O3) nanohybrids stabilized with Gum Arabic (GA) at different water salinities. Nanofluids (NFs) were prepared by dispersing γ-Al2O3 and SiO2 NPs (0.1 wt%) in deionized water (DW), synthetic seawater (SSW), 2, 5, and 10 times diluted samples of synthetic seawater (in short 2-DSSW, 5-DSSW and 10-DSSW, respectively). The challenge is that NPs become unstable in the presence of cations in saline water. Moreover, an attempt was made to introduce NFs with high stability for a long period of time as the optimal NFs. The effects of temperature on the behaviour of optimal NFs in the presence of different base fluids, distinct mass ratios of γ-Al2O3/SiO2 and various concentrations of surfactant were analysed via interfacial tension (IFT) and viscosity measurements. The results of the viscosity measurement showed that with increasing temperature, the NPs dispersed in DW had lower viscosity than NPs dispersed in various salinities. However, the IFT measurement for NPs dispersed in different base-fluids revealed that with increasing temperature and presence of cations in saline water, IFT values decreases. Although, the minimum IFT for hybrid nanofluid (HNF) γ-Al2O3/SiO2 modified with GA and dispersed in 10-DSSW was reported 0.99 mN/m. Finally, according to the micromodel flooding results, in oil-wet conditions, the highest oil recovery for combination γ-Al2O3/SiO2 modified with GA and dispersed in 2-DSSW was reported 60.34%. It was concluded that NFs modified with GA could enhanced applicability of LSWF via delay in breakthrough time and improving sweep efficiency.

Green synthesis-inspired antibacterial, antioxidant and adhesive hydrogels with ultra-fast gelation and hemostasis for promoting infected skin wound healing

Bacterial infections are a serious threat to wound healing and skin regeneration. In recent years, photothermal therapy (PTT) has become one of the most promising tools in the treatment of infectious diseases. However, wound dressings with photo-responsive properties are currently still limited by the difficulties of biosafety and thermal stability brought by the introduction of photosensitizers or photothermal agents. Therefore, how to improve the therapeutic efficiency and biosafety from material design is still a major challenge at present. In this study, the carboxymethyl chitosan (CMCS) and protocatechuic aldehyde (PA) hydrogels based on horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) enzymatic catalysis was developed. Therein, HRP and H2O2 catalyzed cross-linking while polymerizing PA, which not only endowed the hydrogels with photothermal responsiveness but also with good biosafety through this enzyme-catalyzed green approach. Meanwhile, the hydrogels possessed highly efficient bacteriostatic ability with the assistance of near infrared (NIR). Moreover, the ultra-rapid gelation, strong tissue adhesion, high swelling ability, good antioxidant property and hemostatic property of the CMCS-PA hydrogels based on HRP/H2O2 enzymatic catalysis were suitable for the treatment of skin wounds. Meanwhile, NIR-assistant CMCS-PA hydrogels based on HRP/H2O2 enzymatic catalysis reduced inflammation, decreased bacterial infection, and promoted collagen deposition and angiogenesis, which showed remarkable therapeutic effects in a skin wound infection model. All results indicate that this green approach to introduce photothermal property by HRP-catalyzed PA polymerization endows the hydrogels with efficient photothermal conversion efficiency, suggesting that they are promising to provide new options for replacing photothermal agents and photosensitizers. STATEMENT OF SIGNIFICANCE: In recent years, wound dressings with photo-responsive properties are currently still limited by the difficulties of biosafety and thermal stability brought by the introduction of agent photosensitizers or photothermal agents. In this study, the carboxymethyl chitosan and protocatechuic aldehyde hydrogels based on horseradish peroxidase and hydrogen peroxide enzymatic catalysis was developed. The photothermal properties of hydrogels were transformed from absent to present just by horseradish peroxidase-catalyzed protocatechuic aldehyde polymerization in a green approach. Meanwhile, the hydrogels possessed highly efficient bacteriostatic ability with the assistance of near infrared. The green approach of introducing photothermal properties from material design solves the biosafety challenge. Therefore, this study is expected to provide new options for alternative photothermal agents and photosensitizers.

Thiol-Ene Click Reaction in Constructing Liquid Separation Membranes for Water Treatment

In the evolving landscape of water treatment, membrane technology has ascended to an instrumental role, underscored by its unmatched efficacy and ubiquity. Diverse synthesis and modification techniques are employed to fabricate state-of-the-art liquid separation membranes. Click reactions, distinguished by their rapid kinetics, minimal byproduct generation, and simple reaction condition, emerge as a potent paradigm for devising eco-functional materials. While the metal-free thiol-ene click reaction is acknowledged as a viable approach for membrane material innovation, a systematic elucidation of its applicability in liquid separation membrane development remains conspicuously absent. This review elucidates the pre-functionalization strategies of substrate materials tailored for thiol-ene reactions, notably highlighting thiolation and introducing unsaturated moieties. The consequential implications of thiol-ene reactions on membrane properties-including trade-off effect, surface wettability, and antifouling property-are discussed. The application of thiol-ene reaction in fabricating various liquid separation membranes for different water treatment processes, including wastewater treatment, oil/water separation, and ion separation, are reviewed. Finally, the prospects of thiol-ene reaction in designing novel liquid separation membrane, including pre-functionalization, products prediction, and solute-solute separation membrane, are proposed. This review endeavors to furnish invaluable insights, paving the way for expanding the horizons of thiol-ene reaction application in liquid separation membrane fabrication.

Revolutionizing Cardiovascular Health with Nano Encapsulated Omega-3 Fatty Acids: A Nano-Solution Approach

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) offer diverse health benefits, such as supporting cardiovascular health, improving cognitive function, promoting joint and musculoskeletal health, and contributing to healthy aging. Despite their advantages, challenges like oxidation susceptibility, low bioavailability, and potential adverse effects at high doses persist. Nanoparticle encapsulation emerges as a promising avenue to address these limitations while preserving stability, enhanced bioavailability, and controlled release. This comprehensive review explores the therapeutic roles of omega-3 fatty acids, critically appraising their shortcomings and delving into modern encapsulation strategies. Furthermore, it explores the potential advantages of metal-organic framework nanoparticles (MOF NPs) compared to other commonly utilized nanoparticles in improving the therapeutic effectiveness of omega-3 fatty acids within drug delivery systems (DDSs). Additionally, it outlines future research directions to fully exploit the therapeutic benefits of these encapsulated omega-3 formulations for cardiovascular disease treatment.

Inorganic nanoparticle-cored dendrimers for biomedical applications: A review

Hybrid nanostructures exhibit a synergistic combination of features derived from their individual components, showcasing novel characteristics resulting from their distinctive structure and chemical/physical properties. Surface modifiers play a pivotal role in shaping INPs' primary attributes, influencing their physicochemical properties, stability, and functional applications. Among these modifiers, dendrimers have gained attention as highly effective multifunctional agents for INPs, owing to their unique structural qualities, dendritic effects, and physicochemical properties. Dendrimers can be seamlessly integrated with diverse inorganic nanostructures, including metal NPs, carbon nanostructures, silica NPs, and QDs. Two viable approaches to achieving this integration involve either growing or grafting dendrimers, resulting in inorganic nanostructure-cored dendrimers. The initial step involves functionalizing the nanostructures' surface, followed by the generation of dendrimers through stepwise growth or attachment of pre-synthesized dendrimer branches. This hybridization imparts superior qualities to the resulting structure, including biocompatibility, solubility, high cargo loading capacity, and substantial functionalization potential. Combining the unique properties of dendrimers with those of the inorganic nanostructure cores creates a multifunctional system suitable for diverse applications such as theranostics, bio-sensing, component isolation, chemotherapy, and cargo-carrying applications. This review summarizes the recent developments, with a specific focus on the last five years, within the realm of dendrimers. It delves into their role as modifiers of INPs and explores the potential applications of INP-cored dendrimers in the biomedical applications.

Preparation of highly elastic superhydrophobic CNF/Fe3O4 based materials modified in aqueous phase for oil-water separation

Magnetic superhydrophobic materials have broad application prospect in oil-water separation. In this study, a magnetic and superhydrophobic aerogel with lamellar structure was successfully prepared using cellulose nanofibrils (CNF) as the skeleton, Fe3O4 as the magnetic ion, 1H, 1H, 2H, 2H trialkylfluorooctane triethoxysilane (FS) and 3-(2-aminoethyl amino)-propyl trimethoxysilane (AS) as the combined modifier. The prepared aerogel shows lower density (38.63 mg/cm3), excellent magnetic (15.13 emu/g), high elasticity and good oil sorption properties (21 g/g). In addition, FS/AS also exhibits excellent mechanical properties and superhydrophobic ability (water contact angle (WCA) of 151.9 ± 1.4°), as it provides sufficient toughness and low surface energy for the layer-branch structure. It should be noted that the entire preparation process is carried out in the aqueous phase, without the use of any organic solvents, providing a green oil-water separation strategy.

Surface (bio)-functionalization of metallic materials: How to cope with real interfaces?

Metallic materials are an important class of biomaterials used in various medical devices, owing to a suitable combination of their mechanical properties. The (bio)-functionalization of their surfaces is frequently performed for biocompatibility requirements, as it offers a powerful way to control their interaction with biological systems. This is particularly important when physicochemical processes and biological events, mainly involving proteins and cells, are initiated at the host-material interface. This review addresses the state of "real interfaces" in the context of (bio)-functionalization of metallic materials, and the necessity to cope with it to avoid frequent improper evaluation of the procedure used. This issue is, indeed, well-recognized but often neglected and emerges from three main issues: (i) ubiquity of surface contamination with organic compounds, (ii) reactivity of metallic surfaces in biological medium, and (iii) discrepancy in (bio)-functionalization procedures between expectations and reality. These disturb the assessment of the strategies adopted for surface modifications and limit the possibilities to provide guidelines for their improvements. For this purpose, X-ray photoelectrons spectroscopy (XPS) comes to the rescue. Based on significant progresses made in methodological developments, and through a large amount of data compiled to generate statistically meaningful information, and to insure selectivity, precision and accuracy, the state of "real interfaces" is explored in depth, while looking after the two main constituents: (i) the bio-organic adlayer, in which the discrimination between the compounds of interest (anchoring molecules, coupling agents, proteins, etc) and organic contaminants can be made, and (ii) the metallic surface, which undergoes dynamic processes due to their reactivity. Moreover, through one of the widespread (bio)-functionalization strategy, given as a case study, a particular attention is devoted to describe the state of the interface at different stages (composition, depth distribution of contaminants and (bio)compounds of interest) and the mode of protein retention. It is highlighted, in particular, that the occurrence or improvement of bioactivity does not demonstrate that the chemical schemes worked in reality. These aspects are particularly essential to make progress on the way to choose the suitable (bio)-functionalization strategy and to provide guidelines to improve its efficiency.

Rifampicin adsorption and release study using Santa Barbara amorphous-16 modified Al (SBA-16-Al) for a drug delivery system

In this study, the surface modification of Santa Barbara Amorphous-16 (SBA-16) with aluminum (SBA-16-Al) was carried out as a rifampicin matrix for the treatment of tuberculosis. Surface modification of SBA-16 was achieved using the direct-synthesis grafting method. Then, the adsorption and release properties of rifampicin from the SBA-16-Al matrix have been studied in batches. In addition, the SBA-16-Al has been characterized using Fourier-Transform Infrared Spectroscopy (FTIR), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), and Surface Area Analysis (SAA) Brunaur, Emmett and Teller (SAA-BET). The results show that the mesoporous material, the SBA-16-Al has a specific surface area of 843.5 m2 g-1 and 624.3 m2 g-1 for SBA-16, nanometer-sized pore diameters, and an amorphous crystal lattice. The FTIR spectra showed the Al-O bond at 802 cm-1 which indicates the Al group has been successfully added into SBA-16. The adsorption isotherm of rifampicin in SBA-16-Al follows the Freundlich model which illustrates the adsorption is heterogeneous and forms a multilayer. The adsorption of rifampicin is chemisorption which occurs non-spontaneously and is quite stable. The release kinetics of rifampicin in the drug delivery system followed the Higuchi model with k1 0.5472 mg 0.5/hour pH 1.5 and k2 mg 0.5/hour pH 6.5.

Rational Design of Stimuli-Responsive Inorganic 2D Materials via Molecular Engineering: Toward Molecule-Programmable Nanoelectronics

The ability of electronic devices to act as switches makes digital information processing possible. Succeeding graphene, emerging inorganic 2D materials (i2DMs) have been identified as alternative 2D materials to harbor a variety of active molecular components to move the current silicon-based semiconductor technology forward to a post-Moore era focused on molecule-based information processing components. In this regard, i2DMs benefits are not only for their prominent physiochemical properties (e.g., the existence of bandgap), but also for their high surface-to-volume ratio rich in reactive sites. Nonetheless, since this field is still in an early stage, having knowledge of both i) the different strategies for molecularly functionalizing the current library of i2DMs, and ii) the different types of active molecular components is a sine qua non condition for a rational design of stimuli-responsive i2DMs capable of performing logical operations at the molecular level. Consequently, this Review provides a comprehensive tutorial for covalently anchoring ad hoc molecular components-as active units triggered by different external inputs-onto pivotal i2DMs to assess their role in the expanding field of molecule-programmable nanoelectronics for electrically monitoring bistable molecular switches. Limitations, challenges, and future perspectives of this emerging field which crosses materials chemistry with computation are critically discussed.

Covalently surface-grafting α‑zirconium phosphate nanoplatelets enables collagen fiber matrix with ultraviolet barrier, antibacterial, and flame-retardant properties

Manipulating the dispersibility and reactivity of two-dimensional nanomaterials in collagen fibers (CFs) matrix has aroused attention in the fabrication of multifunctional collagen-based nanocomposites. Here, α‑zirconium phosphate nanoplatelets (ZrP NPs) were surface-functionalized with gallic acid (GA) to afford ZrP-GA NPs for engineering CFs matrix. The influence of ZrP-GA NPs on the ultraviolet barrier, antibacterial, and flame-retardant properties of resultant CFs matrix were investigated. Microstructural analysis revealed that ZrP-GA NPs were dispersed and bound within the collagen fibrils and onto the collagen strands in the CFs matrix. The resultant CFs matrix also maintained typical D-periodic structures of collagen fibrils and native branching and interwoven structures of CFs networks with increased porosity and enhanced ultraviolet barrier properties. Inhibition zone testing presented excellent antibacterial activities of the CFs matrix owing to surface grafting of antibacterial GA. Thanks to enhanced dispersion and binding of ZrP NPs with the CFs matrix by surface-functionalization with GA, the resultant CFs matrix reduced the peak heat release rate and the total heat release by 42.9 % and 39.0 %, respectively, highlighting improved flame-retardant properties. We envision that two-dimensional nanomaterials possess great potential in developing reasonable collagen-based nanocomposites towards the manufacture of emergent multifunctional collagen fibers-based wearable electronics.

Effects of filler type and content on mechanical, thermal, and physical properties of carrageenan biocomposite films

This study investigates the influence of various fillers on the properties of carrageenan, a natural polymer derived from red seaweed. Despite its potential for enhanced biocomposite film development, carrageenan faces challenges related to strength. The incorporation of nanoclay into the carrageenan film resulted in a significant increase in film thickness from 0.026 to 0.068 mm. The UV light transmission value for the carrageenan film alone was measured at 30.9 %, whereas films containing 5 wt% of Tetraethyl orthosilicate (TEOS), 3-Aminopropyltriethoxysilane (APTES), and nanoclay exhibited reduced transmission values of 23 %, 18 %, and 1 %, respectively. Notably, the tensile strength of the unfilled carrageenan film was 38.4 MPa, which increased to 38.6, 57, and 60 MPa upon the addition of 3 wt% of nanoclay, APTES, and TEOS fillers, respectively. All fillers contributed to improved tensile strength, with TEOS demonstrating the highest enhancement. The optimal filler content was determined to be 3 wt%. Regarding thermal properties, films containing TEOS displayed higher thermal stability compared to those with APTES, while films incorporating nanoclay exhibited the lowest stability. Findings provide insights into the effects of different fillers on the mechanical, physical and thermal properties of carrageenan films, supporting the development of improved biocomposite materials suitable for application in food packaging.

An underwater stable and durable gelatin composite hydrogel coating for biomedical applications

Developing underwater stable and durable hydrogel coatings with drag-reducing, drug release, and antibacterial properties is essential for lots of biomedical applications. However, most hydrogel coatings cannot meet the requirement of underwater stability and versatility, which severely limits their widespread use. In this work, an underwater stable, durable and substrate-independent gelatin composite hydrogel (GMP) coating is developed through covalent crosslinks, where a silane coupling agent with an unsaturated double bond is grafted onto a substrate of co-deposited polydopamine and polyethylenimine. GMP coating can be easily coated onto various medical device surfaces, such as artificial joints, catheters, tracheal tubes and titanium alloys, showing excellent structural stability and mechanical tunability under extreme conditions of ultrasonic treatment for 1 h (400 W of ultrasonic power) or underwater shearing for 14 days (400 rpm). Besides, friction experiment reveals that GMP coating exhibits good lubrication properties (coefficient of friction < 0.003). The drug-loading and bacterial inhibition ring tests show that the GMP coating has a tunable drug release ability with the final releasing ratios of 70-95% by changing the content of poly (ethylene glycol) diacrylate. This work offers a scalable approach of fabricating bio-functional and stable hydrogel coatings, which can be potentially used in biomedical applications.

Nanomaterial surface modification toolkit: Principles, components, recipes, and applications

Surface-functionalized nanostructures are at the forefront of biotechnology, providing new opportunities for biosensors, drug delivery, therapy, and bioimaging applications. The modification of nanostructures significantly impacts the performance and success of various applications by enabling selective and precise targeting. This review elucidates widely practiced surface modification strategies, including click chemistry, cross-coupling, silanization, aldehyde linkers, active ester chemistry, maleimide chemistry, epoxy linkers, and other protein and DNA-based methodologies. We also delve into the application-focused landscape of the nano-bio interface, emphasizing four key domains: therapeutics, biosensing, environmental monitoring, and point-of-care technologies, by highlighting prominent studies. The insights presented herein pave the way for further innovations at the intersection of nanotechnology and biotechnology, providing a useful handbook for beginners and professionals. The review draws on various sources, including the latest research articles (2018-2023), to provide a comprehensive overview of the field.

Intermolecular Interactions in 3-Aminopropyltrimethoxysilane, N-Methyl-3-aminopropyltrimethoxysilane and 3-Aminopropyltriethoxysilane: Insights from Computational Spectroscopy

In this work, a computational spectroscopy approach was used to provide a complete assignment of the inelastic neutron scattering spectra of three title alkoxysilane derivatives-3-aminopropyltrimethoxysilane (APTS), N-methyl-3-aminopropyltrimethoxysilane (MAPTS), and 3-aminopropyltriethoxysilane (APTES). The simulated spectra obtained from density functional theory (DFT) calculations exhibit a remarkable match with the experimental spectra. The description of the experimental band profiles improves as the number of molecules considered in the theoretical model increases, from monomers to trimers. This highlights the significance of incorporating non-covalent interactions, encompassing classical NH···N, N-H···O, as well as C-H···N and C-H···O hydrogen bond contacts, to achieve a comprehensive understanding of the system. A distinct scenario emerges when considering optical vibrational techniques, infrared and Raman spectroscopy. In these instances, the monomer model provides a reasonable description of the experimental spectra, and no substantial alterations are observed in the simulated spectra when employing dimer and trimer models. This observation underscores the distinctive ability of neutron spectroscopy in combination with DFT calculations in assessing the structure and dynamics of molecular materials.

Microwave-Assisted Silanization of Magnetite Nanoparticles Pre-Synthesized by a 3D Microfluidic Platform

Magnetite nanoparticles (Fe3O4 NPs) are among the most investigated nanomaterials, being recognized for their biocompatibility, versatility, and strong magnetic properties. Given that their applicability depends on their dimensions, crystal morphology, and surface chemistry, Fe3O4 NPs must be synthesized in a controlled, simple, and reproducible manner. Since conventional methods often lack tight control over reaction parameters and produce materials with unreliable characteristics, increased scientific interest has been directed to microfluidic techniques. In this context, the present paper describes the development of an innovative 3D microfluidic platform suitable for synthesizing uniform Fe3O4 NPs with fine-tuned properties. On-chip co-precipitation was performed, followed by microwave-assisted silanization. The obtained nanoparticles were characterized from the compositional and microstructural perspectives by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Moreover, supplementary physicochemical investigations, such as Fourier Transform Infrared Spectroscopy (FT-IR), Kaiser Test, Ultraviolet-Visible (UV-Vis) Spectrophotometry, Dynamic Light Scattering (DLS), and Thermogravimetry and Differential Scanning Calorimetry (TG-DSC) analyses, demonstrated the successful surface modification. Considering the positive results, the presented synthesis and functionalization method represents a fast, reliable, and effective alternative for producing tailored magnetic nanoparticles.

Effects of silica surface modification with silane and poly(ethylene glycol) on flexural strength, protein-repellent, and antibacterial properties of acrylic dental nanocomposites

OBJECTIVE

The main aim of the current work was to develop dental acrylic-based composites with protein-repellent and antibacterial properties by using surface-modified silica nanoparticles. The effects of surface modification of silica nanoparticles in protein-repellent and antibacterial activity and mechanical properties of dental composites including flexural strength, flexural modulus, and hardness were discussed.

METHODS

The surface of silica nanoparticles was first chemically treated with 3-methacryloxypropyltrimethoxysilane (MPS) as a coupling agent and then with poly(ethylene glycol) (PEG) bonded to MPS. Dental acrylic-based composites were prepared with mass fractions of 10, 15, 20, 30, and 40 % of PEG-modified MPS-silica nanoparticles (PMS). The chemical surface modification of silica nanoparticles with MPS and PEG was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA).

RESULTS

The dental composite containing 20 wt% PMS nanoparticles could reduce the protein adsorption by 28 % as compared with a composite containing 20 wt% MPS-modified silica. The antibacterial test indicated that the PMS nanoparticles can significantly reduce the adhesion of Streptococcus mutans and the biofilm formation on the surface of dental composites. It was found that the flexural strength increased by increasing the PMS nanoparticles from 0 to 20 wt% and then decreased by the incorporation of higher percentages of these nanoparticles. Also, with increasing the weight percentage of PMS nanoparticles, the elastic and the flexural modulus and the hardness of resin nanocomposites were increased.

SIGNIFICANCE

In the current work, for the first time, dental resin composites containing PEG were prepared with excellent protein-repellent and antibacterial properties.

Hyaluronic acid-modified yeast β-glucan particles delivering doxorubicin for treatment of breast cancer

Breast cancer is one of the most threatening cancers that poses a great risk to women's health. The anti-tumor drug doxorubicin (DOX) is one of commonly used drugs in the treatment of breast cancer. However, the cytotoxicity of DOX has always been an urgent challenge to be solved. In this study, we report an alternative drug delivery system delivering DOX for reducing its physiological toxicity by using the yeast β-glucan particle (YGP) with a hollow and porous vesicle structure. Briefly, amino groups were grafted onto the surface of YGP with the silane coupling agent, then the oxidized hyaluronic acid (OHA) was attached by Schiff base reaction to get HA-modified YGP (YGP@N=C-HA), finally DOX was encapsulated into YGP@N=C-HA to get DOX-loaded YGP@N=C-HA (YGP@N=C-HA/DOX). In vitro release experiments exhibited the pH-responsive DOX release from YGP@N=C-HA/DOX. Cell experiments displayed that YGP@N=C-HA/DOX had good killing effect on both MCF-7 and 4T1 cells and could be internalized into these cells through CD44 receptors, showing targetability to cancer cells. Furthermore, YGP@N=C-HA/DOX could effectively inhibit tumor growth and reduce the physiological toxicity of DOX. Thus, the YGP-based vesicle provides an alternative strategy for lowering the physiological toxicity of DOX in the medical treatment of breast cancer.

The Mechanical Properties Relationship of Radiation-Cured Nanocomposites Based on Acrylates and Cationic Polymerized Epoxies and the Composition of Silane-Modified Tungsten Disulfide Nanoparticles

The effect of semiconducting tungsten disulfide (WS₂) nanoparticles (NPs), functionalized by either methacryloxy, glycidyl, vinyl, or amino silanes, has been studied in photocuring of acrylate and epoxy resins (the latter photocured according to a cationic mechanism). The curing time, degree of curing (DC), thermal effects, and mechanical properties of the radiation-cured resins were investigated. X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analyses confirmed that a silane coating was formed (1-4 nm) on the NPs' surface having a thickness of 1-4 nm. Fourier transition infrared (FTIR) was used to determine the DC of the nanocomposite resin. The curing time of the epoxy resin, at 345-385 nm wavelength, was 10 to 20 s, while for acrylate, the curing time was 7.5 min, reaching 92% DC in epoxy and 84% in acrylate. The glass transition temperature (Tg) of the photocured acrylates in the presence of WS₂ NPs increased. In contrast to the acrylate, the epoxy displayed no significant variations of the Tg. It was found that the silane surface treatments enhanced the DC. Significant increases in impact resistance and enhancement in shear adhesion strength were observed when the NPs were treated with vinyl silane. A previous study has shown that the addition of WS₂ NPs at a concentration of 0.5 wt.% is the optimal loading for improving the resin's mechanical properties. This study supports these earlier findings not only for the unmodified NPs but also for those functionalized with silane moieties. This study opens new vistas for the photocuring of resins and polymers in general when incorporating WS₂ NPs.

Sol-Gel Approach for Fabricating Silica/Epoxy Nanocomposites

This review focuses on the opportunities provided by sol-gel chemistry for the production of silica/epoxy nanocomposites, with significant representative examples of the "extra situ" approach and an updated description of the "in situ" strategy. The "extra situ" strategy enables the creation of nanocomposites containing highly engineered nanoparticles. The "in situ" approach is a very promising synthesis route that allows us to produce, in a much easier and eco-friendly manner, properly flame-retarded silica/epoxy nanocomposites endowed with very interesting properties. The review highlights the recently proposed mechanism of nanoparticles formation, which is expected to help to design the synthesis strategies of nanocomposites, changing their composition (both for the nanoparticle and matrix nature) and with in situ-generated nanoparticles possibly more complex than the ones obtained, until today, through this route.

An evaluation of antibacterial properties and cytotoxicity of UV-curable biocompatible films containing hydroxyethyl cellulose and silver nanoparticles

The present study aimed to develop biocompatible film materials with antibacterial and anticancer properties that can be cured with UV rays depending on the thiol-en click reaction mechanism. The synthesized m-Ag NPs were added to formulations containing acrylate functionality HEC, pentaerythritol tetrarkis(3-mercaptopropionate), and photoinitiator at different rates (0, 20, 40, and 60 parts per hundred (phr)). The antibacterial activity of the films was evaluated against S. aureus, P. aeruginosa and E. coli by the disk diffusion test. The antibacterial effect of the films did not form an inhibition zone for the control formulation (CmAg0) against bacteria whereas the antibacterial property increased as the Ag NPs content increased in formulations containing m-Ag NPs. The strongest resistance film against the three bacterial species was observed in the CmAg60 formulation with 60 phr silver content, and the inhibition zones for S. aureus, P. aeruginosa, and E. coli were measured as 16.5 ± 0.7, 16.5 ± 2.1, and 16 ± 1.4, respectively. The cytotoxicity of the films against healthy cells and breast cancer cell (MCF-7) lines was investigated with MTT, and it was observed that all films did not cause any inhibition in the structure of the living cell but killed the cells at a high rate in the MCF-7 line. It was mainly observed that the CmAg60 formulation showed 95.576 % cell inhibition against MCF-7. According to these results, it has been predicted that the prepared films will play a vital role in the next generation of cancer treatments.

Ligand Chemistry in Antitumor Theranostic Nanoparticles

ConspectusTheranostic nanoparticles' potential in tumor treatment has been widely acknowledged thanks to their capability of integrating multifaceted functionalities into a single nanosystem. Theranostic nanoparticles are typically equipped with an inorganic core with exploitable physical properties for imaging and therapeutic functions, bioinert coatings for improved biocompatibility and immunological stealth, controlled drug-loading-release modules, and the ability to recognize specific cell type for uptake. Integrating multiple functionalities in a single nanosized construct require sophisticated molecular design and precise execution of assembly procedures. Underlying the multifunctionality of theranostic nanoparticles, ligand chemistry plays a decisive role in translating theoretical designs into fully functionalized theranostic nanoparticles. The ligand hierarchy in theranostic nanoparticles is usually threefold. As they serve to passivate the nanoparticle's surface, capping ligands form the first layer directly interfacing with the crystalline lattice of the inorganic core. The size and shape of nanoparticles are largely determined by the molecular property of capping ligands so that they have profound influences on the nanoparticles' surface chemistry and physical properties. Capping ligands are mostly chemically inert, which necessitates the presence of additional ligands for drug loading and tumor targeting. The second layer is commonly utilized for drug loading. Therapeutic drugs can either be covalently conjugated onto the capping layer or noncovalently loaded onto nanoparticles via drug-loading ligands. Drug-loading ligands need to be equally versatile in properties to accommodate the diversity of drugs. Biodegradable moieties are often incorporated into drug-loading ligands to enable smart drug release. With the aid of targeting ligands which usually stand the tallest on the nanoparticle surface to seek and bind to their corresponding receptors on the target, theranostic nanoparticles can preferentially accumulate at the tumor site to attain a higher precision and quantity for drug delivery. In this Account, the properties and utilities of representative capping ligands, drug-loading ligands, and targeting ligands are reviewed. Since these types of ligands are often assembled in close vicinity to each other, it is essential for them to be chemically compatible and able to function in tandem with each other. Relevant conjugation strategies and critical factors with a significant impact on ligands' performance on nanoparticles are discussed. Representative theranostic nanoparticles are presented to showcase how different types of ligands function synergistically from a single nanosystem. Finally, the technological outlook of evolving ligand chemistry on theranostic nanoparticles is provided.

Interface Wetting Driven by Laplace Pressure on Multiscale Topographies and Its Application to Performance Enhancement of Metal-Composite Hybrid Structure

Surface topography reconstruction is extensively used to address the issue of weak bonding at the polymer-metal interface of metal-composite hybrid structure, while enhancement from this approach is seriously impaired by insufficient interface wetting. In this study, the wetting behavior of polymer on aluminum surfaces with multiscale topographies was theoretically and experimentally investigated to realize stable and complete wetting. Geometric dimensions of multiscale surface topographies have a notable impact on interfacial forces at the three-phase contact line of polymer/air/aluminum, and a competition exists between Laplace pressure and bubble pressure in dominating the wetting behavior. Laplace pressure facilitates the degassing of trapped air bubbles in grooves, bringing more robust interfacial wettability to grooves than dimples and grids. Conversely, dimples with excessive dimensions generate interfacial pores, and this intrinsic mechanism is theoretically unraveled. Moreover, different degrees of interface wetting cause variations in bonding strength of polymer-aluminum interface, which changes from ∼18% improvement to ∼17% reduction compared to original strength. Finally, groove topography perfectly achieved complete wetting between polymer and aluminum and consequently improved flexure performance by over 11% for the aluminum-carbon fiber hybrid side impact bar, which verifies the importance of complete wetting at a part scale. This study deepens the understanding of wetting behavior and clarifies the intrinsic correlation between interfacial bonding performance and surface topography.

Molecular Simulation for Guiding the Design and Optimization of Mixed Matrix Membranes (MMMs) in the Pervaporation Process

Molecular simulation has been used extensively in the study of pervaporation membranes as a new economical and environmentally friendly research method. In this paper, A-SiO₂/PDMS-PTFE mixed matrix membranes (MMMs) were prepared by molecular-simulation-guided experiments to achieve the separation of dimethyl carbonate/methanol (DMC/MeOH)) azeotropes. The interaction energy, X-ray diffraction pattern mean square displacement, and density field between PDMS and inorganic particles were analyzed by molecular dynamics simulations. The dissolution and diffusion processes of the DMC/MeOH azeotropes system in the MMM were simulated, and the surface-silylated silica (A-SiO₂) with relatively better performance was screened. Based on the simulation results, A-SiO₂/PDMS-PTFE MMMs were prepared by the coblending method, and the pervaporation separation performance of MMM membranes for DMC/MeOH azeotropes with different A-SiO₂ loadings was investigated. When the A-SiO₂ loading was 15 wt %, the separation factor of DMC/MeOH azeotropes at 50 °C was 4.74 and the flux was 1178 g m^-2 h^-1, which was consistent with the expected results of the simulation. The MMMs showed good stability in pervaporation over a period of up to 120 h. This study demonstrates that molecular simulations can provide a viable means for pretest screening and validation of experimental mechanisms, and to a certain extent, guide the design and optimization of pervaporation membranes.

Can Superhydrophobic PET Surfaces Prevent Bacterial Adhesion?

Prevention of bacterial adhesion is a way to reduce and/or avoid biofilm formation, thus restraining its associated infections. The development of repellent anti-adhesive surfaces, such as superhydrophobic surfaces, can be a strategy to avoid bacterial adhesion. In this study, a polyethylene terephthalate (PET) film was modified by in situ growth of silica nanoparticles (NPs) to create a rough surface. The surface was further modified with fluorinated carbon chains to increase its hydrophobicity. The modified PET surfaces presented a pronounced superhydrophobic character, showing a water contact angle of 156° and a roughness of 104 nm (a considerable increase comparing with the 69° and 4.8 nm obtained for the untreated PET). Scanning Electron Microscopy was used to evaluate the modified surfaces morphology, further confirming its successful modification with nanoparticles. Additionally, a bacterial adhesion assay using an Escherichia coli expressing YadA, an adhesive protein from Yersinia so-called Yersinia adhesin A, was used to assess the anti-adhesive potential of the modified PET. Contrarily to what was expected, adhesion of E. coli YadA was found to increase on the modified PET surfaces, exhibiting a clear preference for the crevices. This study highlights the role of material micro topography as an important attribute when considering bacterial adhesion.

Polyamide 11 Composites Reinforced with Diatomite Biofiller-Mechanical, Rheological and Crystallization Properties

Amorphic diatomaceous earth is derived from natural sources, and polyamide 11 (PA11) is produced from materials of natural origin. Both of these materials show a low harmfulness to the environment and a reduced carbon footprint. This is why the combination of these two constituents is beneficial not only to improve the physicochemical and mechanical properties of polyamide 11 but also to produce a biocomposite. For the purpose of this paper, the test biocomposite was produced by combining polyamide 11, as well as basic and pre-fractionated diatomaceous earth, which had been subjected to silanization. The produced composites were used to carry out rheological (melt flow rate-MFR), mechanical (tensile strength, bending strength, impact strength), crystallographic (X-ray Diffraction-XRD), thermal and thermo-mechanical (differential scanning calorimetry-DSC, dynamic mechanical thermal analysis-DMTA) analyses, as well as a study of hydrophobic-hydrophilic properties of the material surface (wetting angle) and imaging of the surface of the composites and the fractured specimens. The tests showed that the additive 3-aminopropyltriethoxysilane (APTES) acted as an agent that improved the elasticity of composites and the melt flow rate. In addition, the produced composites showed a hydrophilic surface profile compared to pure polylactide and polyamide 11.

Surface modification of TiO2 nanoparticles with organic molecules and their biological applications

In recent years, titanium(IV) dioxide nanoparticles (TiO₂NPs) have shown promising potential in various biological applications such as antimicrobials, drug delivery, photodynamic therapy, biosensors, and tissue engineering. For employing TiO₂NPs in these fields, their nanosurface must be coated or conjugated with organic and/or inorganic agents. This modification can improve their stability, photochemical properties, biocompatibility, and even surface area for further conjugation with other molecules such as drugs, targeting molecules, polymers, etc. This review describes the organic-based modification of TiO₂NPs and their potential applications in the mentioned biological fields. In the first part of this review, around 75 recent publications (2017-2022) are mentioned on the common TiO₂NP modifiers including organosilanes, polymers, small molecules, and hydrogels, which improve the photochemical features of TiO₂NPs. In the second part of this review, we presented 149 recent papers (2020-2022) about the use of modified TiO₂NPs in biological applications, in which specific bioactive modifiers are introduced in this part with their advantages. In this review, the following information is presented: (1) the common organic modifiers for TiO₂NPs, (2) biologically important modifiers and their benefits, and (3) recent publications on biological studies on the modified TiO₂NPs with their achievements. This review shows the paramount significance of the organic-based modification of TiO₂NPs to enhance their biological effectiveness, paving the way toward the development of advanced TiO₂-based nanomaterials in nanomedicine.

A Comprehensive Review on Barium Titanate Nanoparticles as a Persuasive Piezoelectric Material for Biomedical Applications: Prospects and Challenges

Stimulation of cells with electrical cues is an imperative approach to interact with biological systems and has been exploited in clinical practices over a wide range of pathological ailments. This bioelectric interface has been extensively explored with the help of piezoelectric materials, leading to remarkable advancement in the past two decades. Among other members of this fraternity, colloidal perovskite barium titanate (BaTiO₃ ) has gained substantial interest due to its noteworthy properties which includes high dielectric constant and excellent ferroelectric properties along with acceptable biocompatibility. Significant progression is witnessed for BaTiO₃ nanoparticles (BaTiO₃ NPs) as potent candidates for biomedical applications and in wearable bioelectronics, making them a promising personal healthcare platform. The current review highlights the nanostructured piezoelectric bio interface of BaTiO₃ NPs in applications comprising drug delivery, tissue engineering, bioimaging, bioelectronics, and wearable devices. Particular attention has been dedicated toward the fabrication routes of BaTiO₃ NPs along with different approaches for its surface modifications. This review offers a comprehensive discussion on the utility of BaTiO₃ NPs as active devices rather than passive structural unit behaving as carriers for biomolecules. The employment of BaTiO₃ NPs presents new scenarios and opportunity in the vast field of nanomedicines for biomedical applications.

Robust and Scalable In Vitro Surface Mineralization of Inert Polymers with a Rationally Designed Molecular Bridge

The artificial integration of inorganic materials onto polymers to create the analogues of natural biocomposites is an attractive field in materials science. However, due to significant diversity in the interfacial properties of two kinds of materials, advanced synthesis methods are quite complicated and the resultant materials are always vulnerable to external environments, which limits their application scenarios and makes them unsuitable for scalable production. Herein, we report a simple and universal approach to achieve robust and scalable surface mineralization of polymers using a rationally designed triple functional molecular bridge of fluorosilane, 3-[(perfluorohexyl sulfonyl) amino] propyltriethoxy silane (PFSS). In a two-step solution deposition, the fluoroalkyl and siloxane of the PFSS take charge of its adhesion and immobilization onto polymers by hydrophobic interaction and wrapping-like chemical cross-linking, and then the assembly and growth of inorganic nanoclusters for integration are achieved by strong chemical coordination of PFSS sulfonamide. The versatile mineralization of inorganic oxides (e.g., TiO₂, SiO₂, and Fe₂O₃) onto chemically inert polymer surfaces was realized very well. The resultant mineralized materials exhibit robust and multiple functionalities for hostile applications, such as hydrophilic membranes for removing oils in strong acidic and alkaline wastewaters, fabrics with advanced anti-bacteria for healthy wearing, and plates with strong mechanical performance for better use. Experimental results and theoretical calculations confirmed the homogenous distribution of the PFSS onto polymers via cross-linking for robust coordination with inorganic oxides. These results demonstrate a skillful enlightenment in the design of high-performance mineralized polymer materials used as membranes, fabrics, and medical devices.

Synthesis and Surface Modification of Iron Oxide Nanoparticles for the Extraction of Cadmium Ions in Food and Water Samples: A Chemometric Study

In this project, a prompt, efficient, and effective method for Cd2+ ions extraction from different food and water samples using magnetic dispersion-based solid phase extraction by functionalized iron oxide nanoparticles was proposed. Iron oxide nanoparticles were synthesized through the co-precipitation method followed by functionalization with tetraethyl orthosilicate (TEOS) and 3-aminopropyl silane (APTES) to obtain Fe3O4@SiO2@APTES. This composite was characterized through different techniques, including vibrating sample magnetometer, dynamic light scattering, zeta potential, FTIR, SEM, XRD, and BET. Variables studied were pH, temperature, sorbent amount, sonication time, and sample and eluent volume affecting the sorption efficacy of freshly synthesized sorbent. Plackett–Burman design was utilized for the identification of significant factors for microextraction of target analyte, while the central composite design was utilized for the optimization of significant factors. Detection and quantification limits obtained were 0.17 and 0.58 μgL−1, respectively, with an enhancement factor of 83.5. Under optimum conditions, Fe3O4@SiO2@APTES showed good stability even after >80 adsorption/desorption cycles run while maintaining over 96% analyte recoveries. The developed method was validated by assessing certified reference materials and standard addition methodology for Cd2+ detection in real samples. To confirm the precision, repeatability (RSDr) and reproducibility (RSDR) were calculated and found as <3.0 (n = 7) and <7.5 (n = 15), respectively. Furthermore, in accordance with the ISO/IEC 17025 recommendations, the validation was also confirmed through a “bottom-up” approach while considering all possible uncertainties in data.

Preparation of a 3D printable high-performance GelMA hydrogel loading with magnetic cobalt ferrite nanoparticles

Osteosarcoma remains a worldwide concern due to the poor effectiveness of available therapies in the clinic. Therefore, it is necessary to find a safe and effective therapy to realize the complete resection of osteosarcoma and reconstruction of the bone defect. Magnetic hyperthermia based on magnetic nanoparticles can kill tumor cells by raising the temperature without causing the side effects of conventional cancer treatments. This research aims to design a high-performance magnetic hydrogel composed of gelatin methacrylate and highly magnetic cobalt ferrite (CFO) nanoparticles for osteosarcoma treatment. Specifically, CFO is surface functionalized with methacrylate groups (MeCFO). The surface modified CFO has good biocompatibility and stable solution dispersion ability. Afterward, MeCFO nanoparticles are incorporated into GelMA to fabricate a three-dimensional (3D) printable MeCFO/GelMA magnetic hydrogel and then photocross-linked by UV radiation. MeCFO/GelMA hydrogel has high porosity and swelling ability, indicating that the hydrogel possesses more space and good hydrophily for cell survival. The rheological results showed that the hydrogel has shear thinning property, which is suitable as a bioprinting ink to produce desired structures by a 3D printer. Furthermore, 50 μg/mL MeCFO not only decreases the cell activity of osteosarcoma cells but also promotes the osteogenic differentiation of mBMSCs. The results of the CCK-8 assay and live/dead staining showed that MeCFO/GelMA hydrogel had good cytocompatibility. These results indicated that MeCFO/GelMA hydrogel with potential antitumor and bone reconstruction functions is a promising therapeutic strategy after osteosarcoma resection.

Review: 3-Aminopropyltriethoxysilane (APTES) Deposition Methods on Oxide Surfaces in Solution and Vapor Phases for Biosensing Applications

Surface functionalization and bioreceptor immobilization are critical processes in developing a highly sensitive and selective biosensor. The silanization process with 3-aminopropyltriethoxysilane (APTES) on oxide surfaces is frequently used for surface functionalization because of beneficial characteristics such as its bifunctional nature and low cost. Optimizing the deposition process of the APTES layer to obtain a monolayer is crucial to having a stable surface and effectively immobilizing the bioreceptors, which leads to the improved repeatability and sensitivity of the biosensor. This review provides an overview of APTES deposition methods, categorized into the solution-phase and vapor-phase, and a comprehensive summary and guide for creating stable APTES monolayers on oxide surfaces for biosensing applications. A brief explanation of APTES is introduced, and the APTES deposition methods with their pre/post-treatments and characterization results are discussed. Lastly, APTES deposition methods on nanoparticles used for biosensors are briefly described.

NH2-CuO-MCM-41 covalently cross-linked multipurpose membrane for applications in water treatment: Removal of hazardous pollutants from water, water desalination and anti-biofouling performance

The current study was planned to fabricate a new set of membranes to target multiple application areas such as desalting, removal of micropollutants and antibiofouling performance. In-situ incorporated copper oxide to MCM-41 (CuO-MCM-41) was synthesized and amine (-NH₂) functionalized by reacting with N1-(3-trimethoxy silylpropyl) diethylenetriamine (NTSDETA) yielding NH₂-CuO-MCM-41. Different concentrations of NH₂-CuO-MCM-41 were covalently cross-linked in polyamide active layer during interfacial polymerization (IP) between N, N'-bis(3-aminopropyl)ethylenediamine and terephthaloyl chloride (TPC) on polysulfone/poly ester terephthalate (PS/PET) support. The membranes were extensively characterized by Water Contact Angle (WCA), Scanning Electron Microscopy (SEM), Fourier Transform Infra-red (FTIR) spectroscopy, Energy Dispersive X-ray (EDX) analysis, Elemental mapping and Powder X-ray Diffraction (PXRD). From among the different versions of X-CuO-MCM-41/PA@PS/PET membranes, the 0.05%-CuO-MCM-41/PA@PS/PET membrane showed best performance in terms of rejecting a variety of salts, micropollutants and antibiofouling. The 0.05%-CuO-MCM-41/PA@PS/PET showed >98% rejection of MgCl₂ and 78% rejection of caffeine with a permeate flux of 16 LMH at 25 bar. The 0.1-NH₂-CuO-MCM-41inhibited S. aureus growth by 51.7%. Hence, the current strategy of membrane fabrication proved to be highly efficient for multipurpose applications in water treatment.

27Al Solid-State Magic-Angle Spinning NMR Studies of Aluminum Powder Particle Surfaces Treated with a Methyltriethoxysilane Coupling Agent under Acidic Conditions

We report on the reaction between methyltriethoxysilane (MTES) and micrometer-sized aluminum particles, facilitated by HCl. This reaction ultimately produces silane-coated aluminum particles. Using ²⁷Al magic-angle spinning solid-state nuclear magnetic resonance, we find that aluminum powder starts with a mixture of tetrahedrally, pentahedrally, and octahedrally coordinated aluminum, with the pentahedral species dominating. In the presence of HCl, however, the aluminum undergoes a restructuring, so that octahedrally coordinated aluminum is the dominant species. Using diffuse reflectance infrared spectroscopy to confirm the deposition of silane, we find that this restructuring of the aluminum in the presence of HCl is both a sufficient and necessary condition for the deposition of the silane.

A review on recent advances in the applications of composite Fe3O4 magnetic nanoparticles in the food industry

Fe3O4 magnetic nanoparticles (MNPs) have attracted tremendous attention due to their superparamagnetic properties, large specific surface area, high biocompatibility, non-toxicity, large-scale production, and recyclability. More importantly, numerous hydroxyl groups (-OH) on the surface of Fe3O4 MNPs can provide coupling sites for various modifiers, forming versatile nanocomposites for applications in the energy, biomedicine, and environmental fields. With the development of science and technology, the potential of nanotechnology in the food industry has also gradually become prominent. However, the application of composite Fe3O4 MNPs in the food industry has not been systematically summarized. Herein, this article reviews composite Fe3O4 MNPs, including their properties, modifications, and physical functions, as well as their applications in the entire food industry from production to processing, storage, and detection. This review lays a solid foundation for promoting food innovation and improving food quality and safety.

Photocatalytic effect-assisted antimicrobial activities of acrylic resin incorporating zinc oxide nanoflakes

To overcome the deficiency of the antimicrobial effect of polymer, zinc oxide nanoparticles have been widely utilized as advanced nanofillers due to their antimicrobial and photocatalytic activity. However, the underlying antimicrobial mechanism has not been fully understood apart from topological and physical characteristics. In this study, we prepared zinc oxide nanoparticles-based acrylic resin to explore its antimicrobial mechanism under controlled mechanophysical conditions by using silane-treated zinc oxide nanoflakes (S-ZnNFs). S-ZnNFs incorporated acrylic resin (poly(methyl methacrylate), PMMA) composites up to 2 wt% were selected based on comparable mechanophysical properties (e.g., roughness, wettability, strength and hardness), possibly affecting antimicrobial properties beyond the zinc oxide nanoparticle effect, to bare PMMA. Antimicrobial adhesion results were still observed in 2 wt% S-ZnNFs incorporated PMMA using Candida albicans (C. albicans), one of the fungal infection species. In order to confirm the antimicrobial effects by photocatalysis, we pre-exposed the UV light on 2 wt% S-ZnNF composites before cell seeding, revealing synergetic antimicrobial effect via additional reactive oxygen species (ROS) generation to C. albicans over zinc oxide nanoparticle-induced one. RNA-seq analysis revealed distinguished cellular responses between zinc oxide nanoparticles and UV-mediated photocatalytic effect, but both linked to generation of intracellular ROS. Thus, the above data suggest that induction of high intracellular ROS of C. albicans was the main antimicrobial mechanism under controlled mechanophysical parameters and synergetic ROS accumulation can be induced by photocatalysis, recapitulating a promising use of a S-ZnNFs or possibly zinc oxide nanoparticles as intracellular-ROS-generating antimicrobial nanofillers in acrylic composite for biomedical applications.

New Insights into Amino-Functionalization of Magnetic Nanoplatelets with Silanes and Phosphonates

Magnetic nanoplatelets (NPLs) based on barium hexaferrite (BaFe₁₂O₁₉) are suitable for many applications because of their uniaxial magneto-crystalline anisotropy. Novel materials, such as ferroic liquids, magneto-optic composites, and contrast agents for medical diagnostics, were developed by specific surface functionalization of the barium hexaferrite NPLs. Our aim was to amino-functionalize the NPLs’ surfaces towards new materials and applications. The amino-functionalization of oxide surfaces is challenging and has not yet been reported for barium hexaferrite NPLs. We selected two amine ligands with two different anchoring groups: an amino-silane and an amino-phosphonate. We studied the effect of the anchoring group, backbone structure, and processing conditions on the formation of the respective surface coatings. The core and coated NPLs were examined with transmission electron microscopy, and their room-temperature magnetic properties were measured. The formation of coatings was followed by electrokinetic measurements, infrared and mass spectroscopies, and thermogravimetric analysis. The most efficient amino-functionalization was enabled by (i) amino-silanization of the NPLs precoated with amorphous silica with (3-aminopropyl)triethoxysilane and (ii) slow addition of amino-phosphonate (i.e., sodium alendronate) to the acidified NPL suspension at 80 °C.