Chemical Modification Research Articles

Nanosilica/recycled polycarbonate composites for electronic packaging

Several simple methods were performed to recycle compact discs (CDs) using an alkaline solution. The hydrophilic silica nanoparticles were incorporated into the recycled deinked polycarbonate CDs, and these particles affected the dielectric, structure, and thermal properties of the recycled polycarbonates. The thermal properties of recycled CDs were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). No significant change in the thermal stability of polycarbonate/silica nanocomposites was observed with the mechanical /chemical modifications. X-ray diffraction (XRD) revealed the structural aspects, showing a correlation between crystallinity, silica nanoparticles, and modification methods. The mechanically treated sample after chemical handling had the lowest degree of crystallinity (48%), showing that the modification methods enhanced the formation of the amorphous state, thus affecting its dielectric properties. Scanning electron microscopy (SEM) characterized the CD samples' microstructure and morphology. Finally, the dielectric properties were studied using broadband dielectric spectroscopy (BDS) in the 101 - 106 Hz range. The samples prepared using chemical and mechanical treatments were of low dielectric loss. This increases its importance when such samples are used as antistatic charge materials. For these reasons, recycled PC/SiO2 nanocomposites are recommended as effective packaging materials for electronic components.

Constructing dual-ligand Ce-MOF on graphene oxide modified with polydopamine endowing polyurethane coating with long-term smart anti-corrosion and mechanical robustness

Traditional mono-functional anti-corrosion coatings are unable to meet the long-term corrosion resistance requirements of metal materials, therefore developing multifunctional anti-corrosion coatings have broad application prospects. In this work, long-lasting anti-corrosion coatings with superhydrophobic and self-healing properties were successfully prepared by in-situ growth of dual-ligand cerium-based metal–organic framework (Ce-MOF) on the surface of graphene oxide (GO), followed by chemical modification with polydopamine (PDA), resulting in 5B level of adhesion and excellent mechanical robustness. The superhydrophobic surface, as the external armor of the coating, can effectively block the penetrating path of corrosive media. Meanwhile, the MOF structure formed by the coordination of 2-mercaptobenzimidazole (2-M) with cerium ions endows the coating with smart self-healing properties and long-lasting corrosion resistance. Electrochemical tests showed that the low-frequency impedance modulus value of the superhydrophobic coating still reached 3.82 × 108 Ω cm2 after 30 days salt immersion. Due to the formation of protective films and insoluble precipitates at the defect site by 2-M and cerium ions, the scratches on the coating were significantly reduced after 40 days salt spray experiment, demonstrating the self-healing ability of the coating. This multifunctional anti-corrosion coating provides a new approach for preparing coatings with long-term effective corrosion resistance.

NK Cell-Based Cancer Immunotherapies: Current Progress, Challenges and Emerging Opportunities.

Natural killer (NK) cells are vital innate immune cells that play a crucial role in cancer therapy. They are targeted by therapies designed to modulate, retain, and enhance their antitumor function in vivo. In addition to whole-cell therapy, NK cell-derived exosomes (NDEs) offer high immune safety and are easily subject to chemical, biological, and immunological modifications. This makes them suitable for use in combination with various current cancer therapies to enhance efficacy, treatment outcomes, and reduce side effects in vivo. This review aims to outline summarizes the antitumor potential of NK cells, as well as the current challenges and opportunities in NK cell-based immunotherapies such as allogeneic and autologous NK cell transplantation, CAR NK cell therapy, and the use of cytokines and monoclonal antibodies. The review also explores the dual regulatory effects of tumor exosomes on NK cells, and highlights the potential of NDEs, either alone or in combination with other antitumor therapies, to reprogram the immunosuppressive tumor microenvironment and expedite the therapeutic effects of cancer immunotherapy in future clinical research.

Physicochemically modified polymer-based fluidic gates with tunable wetting properties for intelligent liquid manipulations

The creation of a selective flow path and the regulation of a flow rate are of critical importance for polymer-based devices that manipulate liquid at the microscale. The formation of a 3D interconnected network of voids (i.e., physical volumetric modification) and the addition of a nonionic surfactant, Silwet L-77, (i.e., chemical volumetric modification) are expected to affect the wetting properties of polymers, thereby achieving selective gating effect in the polymer-based devices as an appropriate technology. Here, a set of polydimethylsiloxane (PDMS)-based fluidic gates (F-gates) were developed to enable selectivity for liquids and flow-rate control of the liquids by tuning the wetting properties of PDMS with the physicochemical volumetric modifications. For water and oil with different surface tensions (STs), the effects of the physical and chemical volumetric modifications on the fluidic gating of PDMS were quantitatively characterized in terms of contact angle, mass flow rate, and liquid absorption speed. The applicability of PDMS-based F-gates to the selective separation of oil and water even from oil-in-water emulsion was demonstrated by fabricating Janus PDMS-based F-gates. Our physicochemical volumetric modifications were also extensively analyzed to examine whether they satisfy the technological, economic, and ecological requirements of appropriate technology. This is the first effort to tailor the wetting properties of PDMS through physicochemical volumetric modifications, thus configuring a set of PDMS-based F-gates that act both as a separator for liquids of different STs and as a switch for fluid flows.

Physical and chemical surface modification by laser polishing of CuZn42 parts produced by laser powder bed fusion

The widespread use of Cu-Zn alloys containing lead (Pb) in plumbing applications poses significant health risks due to potential Pb leaching into drinking water. In response to international legislation aimed at reducing or eliminating Pb in metal alloys, there is an increasing demand for environmentally friendly brass. In this experimental work, authors show that during the Laser Beam Powder Bed Fusion (PBF-LB) process of the CuZn42 (CW510L) alloy, small particles only a few microns large mixed with large particles that are hundreds of microns in size, are spattered from the material. Large particles show average Zn/Cu ratio around 0.22, while for small particles it increases up to 3, against a nominal value of 0.72 for the CW510L alloy. The fallout of such particles on the produced part enriches surface of Zn, thus altering the surface chemical composition with an increase in Zn concentration beyond the acceptance limit of 43 at.%. To restore the standard chemical composition of the surface, a treatment based on the ablation of the surface material by a laser beam was proposed. Results clearly show that, after the laser treatment, the chemical composition of the surface is completely restored, and the standard properties recovered.

Impact of processing and storage on citrus fiber functionality: Insights from spectroscopic techniques

To deliver their functionality when used in applications, citrus fibers need to be rehydrated. Factors such as chemical composition, structural organization as well as chemical surface composition are known to influence this functionality. Processing and storage conditions can affect these parameters, making it challenging to maintain stable functionality. This study used Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) to evaluate the effects of preparation and storage on citrus fibers. Samples dried at different scales and stored for 360 days under room and accelerated conditions were assessed for water holding capacity (WHC), water swelling capacity (WSC), and gel rigidity (G′). The results showed a decline in WHC, WSC, and G′ over time, confirming that aging negatively impacts moisture retention, particularly under higher water content or temperature. Drying scale had no effect on chemical composition or structure, but changes in the elemental surface composition of carbon and oxygen were noted. While prolonged storage altered the polysaccharides' chemical composition and structure, leading to functionality loss, XPS analysis revealed no changes in surface composition. Loss of functionality cannot be explained by chemical surface composition modifications.

Peanut Hull lignin/ecamsule·2Na hollow nanoparticles (P/E LNPs): A natural light-coloured, broad-spectrum, highly antioxidant, and safe lignin-based sunscreen.

Lignin represents a potentially significant natural sunscreen alternative due to its good UV-absorbing ability, but its poor UVA absorption and dark colour are still obstacles. Numerous methods have been developed to whiten the colour of lignin, mainly including aromatic ring interruption and hydroxyl group blocking. However, these complicated procedures would weaken the UV-blocking and radical scavenging abilities. Here, we develop a strategy for the valorization of lignin in sunscreen to overcome their drawbacks by the in situ self-assembly of the natural light-coloured peanut hull lignin with the commercially available UV-protectant Ecamsule·2Na to obtain peanut hull lignin/Ecamsule·2Na hollow nanoparticles (P/E LNPs). The results show that the sun protection factor (SPF) value increased from 20 to 27, and the antioxidant capacity increased exponentially with a scavenging rate of up to 82 % at the extremely low dosage up to 0.1 mg/L of P/E LNPs. In addition, their good biocompatibility and safety were further confirmed by in vitro cytotoxicity analysis. In summary, we have successfully prepared a safe, broad-spectrum, light-coloured, and highly antioxidant, peanut hull lignin-based sunscreen that avoids any complicated chemical modifications to meet the commercial sunscreen requirement and also provides a new solution for the valorization of lignin from the vast amount of waste fruit hulls.

Functionalisation of chitosan with methacryloyl and crotonoyl groups as a strategy to enhance its mucoadhesive properties

Mucoadhesive polymers are crucial for prolonging drug retention on mucosal surfaces. This study focuses on synthesising and characterising novel derivatives by reacting chitosan with crotonic and methacrylic anhydrides. The structure of the resulting derivatives was confirmed using proton-nuclear magnetic resonance spectroscopy and Fourier-transform infrared spectroscopy. It was established that the degree of substitution plays a crucial role in the pH-dependent solubility profiles and electrophoretic mobility of the chitosan derivatives. Spray-drying chitosan solutions enabled preparation of microparticles, whose mucoadhesive properties were evaluated using fluorescence flow-through studies and tensile test, demonstrating improved retention on sheep nasal mucosa for modified derivatives. Acute toxicity studies conducted in vivo using planaria and in vitro using MTT assay with the Caco-2 cell line, a model of the mucosal epithelium in vitro, showed that the novel derivatives are not cytotoxic. These findings emphasise the potential of tailored chitosan chemical modifications for enhancing transmucosal drug delivery.

Hyaluronic acid act as drug self-assembly chaperone and co-assembled with celalstrol for ameliorating non-alcoholic steatohepatitis

Nanoformulations of therapeutic drugs with diverse chemical structures are often complex to produce and lack a universal synthesis approach. Herein, we demonstrate that hyaluronic acid (HA) can function as an assembly chaperone, facilitating the formulation of various chemical compounds into nanoparticles without necessitating chemical modification. As a proof of concept, celastrol-HA co-assembled nanoparticles (CHNPs) were synthesized and utilized in the multifactorial treatment of non-alcoholic steatohepatitis (NASH). By simply blending an aqueous solution of HA and celastrol, we achieved the formation of homogeneous, stable, and biocompatible nanoparticles, effectively addressing the critical issues associated with celastrol's poor water solubility and high systemic toxicity. of celastrol. Ex vivo and in vivo experiments demonstrated that CHNPs ameliorated NASH by inhibiting macrophage M1 polarization, reducing liver inflammation and lipid deposition, and improving metabolic disorders. Furthermore, CHNPs reduced systemic toxicity and enhanced the bioavailability of celastrol. The simplicity of the HA-based nanoparticles may facilitate the development of translational nanomedicines.

Targeting c-Met in Cancer Therapy: Unravelling Structure-Activity Relationships and Docking Insights for Enhanced Anticancer Drug Design.

The c-Met receptor, a pivotal player in oncogenesis and tumor progression, has become a compelling target for anticancer drug development. This review explores the intricate landscape of Structure-Activity Relationship [SAR] studies and molecular binding analyses performed on c-Met inhibitors. Through a comprehensive examination of various chemical scaffolds and modifications, SAR investigations have elucidated critical molecular features essential for the potent inhibition of c-Met activity. Additionally, molecular docking studies have provided invaluable insights into how c-Met inhibitors interact with their target receptor, facilitating the rational design of novel compounds with enhanced efficacy and selectivity. This review highlights key findings from recent SAR and docking studies, particularly focusing on the structural determinants that govern inhibition potency and selectivity. Furthermore, the integration of computational methodologies with experimental approaches has accelerated the discovery and optimization of c-Met inhibitors, fostering the advancement of promising candidates for clinical applications. Overall, this review underscores the pivotal role of SAR and molecular docking studies in advancing our understanding of c-Met inhibition and guiding the rational design of next-generation anticancer agents targeting this pathway.

Creation of Excitation-Driven Hypervalent Tin(IV) Compounds For Aggregation-Induced Emission and Application to Thermoresponsive Luminescent Films Below Freezing Point.

Although many researchers have devoted their much effort to establish the strategy for developing a stimuli-responsive molecule and tuning of their properties according to the preprogrammed design, it is still challenging to create desired molecules from the scratch. We recently demonstrated that the molecules with a large structural difference between the theoretically optimized structures in the ground and excited states have a potential to exhibit stimuli-responsive luminescent properties. We defined these molecules as an excitation-driven molecule and have shown that they are a versatile platform for designing stimuli-responsive luminescent molecules. Herein, based on the concept of excitation-driven molecules, we show that the hypervalent tin-fused azomethine (TAm) compounds possessing aggregation-induced emission (AIE) properties can be obtained by simple chemical modification with a methyl group although conventional TAm derivatives are well known to be highly luminescent compounds in solution. Furthermore, by combining the solid-state luminescence property of AIE and the coordination number shifts of the hypervalent tin atom, the thermoresponsive films operating below the freezing point are fabricated with the polymer. In this study, we apply the concept of excitation-driven molecules to the hypervalent compounds and demonstrate to obtain the novel functional materials.

SYNTHESIS OF HYDROPHOBIC COATINGS ON STAINLESS-STEEL MESH AND ITS PERFORMANCE

Hydrophobic coatings were fabricated on 400-mesh 304 stainless steel by combining hydrothermal treatment and chemical modification. The hydrophobicity of the surfactant coatings was evaluated. The fabricated coatings were characterized by scanning electron microscopy, contact angle measurements and X-ray diffraction. The results revealed that a hydrophobic coating with a water contact angle of [Formula: see text] could be successfully synthesized under specific conditions: a concentration of 0.005[Formula: see text]mol⋅L[Formula: see text] C[Formula: see text]H[Formula: see text]SO4Na and subsequent modification with a 1[Formula: see text]mol⋅L[Formula: see text] ethanol stearate solution for 24[Formula: see text]h. This outcome highlights the potential of this methodology for producing highly efficient hydrophobic coatings for stainless steel mesh substrates.

Development of bioconjugate-based delivery systems for nucleic acids.

Nucleic acids are a class of drugs that can modulate gene and protein expression by various mechanisms, namely, RNAi, mRNA degradation by RNase H cleavage, splice modulation, and steric blocking of protein binding or mRNA translation, thus exhibiting immense potential to treat various genetic and rare diseases. Unlike protein-targeted therapeutics, the clinical use of nucleic acids relies on Watson-Crick sequence recognition to regulate aberrant gene expression and impede protein translation. Though promising, targeted delivery remains a bottleneck for the clinical adoption of nucleic acid-based therapeutics. To overcome the delivery challenges associated with nucleic acids, various chemical modifications and bioconjugation-based delivery strategies have been explored. Currently, liver targeting by N-acetyl galactosamine (GalNAc) conjugation has been at the forefront for the treatment of rare and various metabolic diseases, which has led to FDA approval of four nucleic acid drugs. In addition, various other bioconjugation strategies have been explored to facilitate active organ and cell-enriched targeting. This review briefly covers the different classes of nucleic acids, their mechanisms of action, and their challenges. We also elaborate on recent advances in bioconjugation strategies in developing a diverse set of ligands for targeted delivery of nucleic acid drugs.

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.

Copper Catalysts Anchored on Cysteine-Functionalized Polydopamine-Coated Magnetite Particles: A Versatile Platform for Enhanced Coupling Reactions.

Cysteine plays a crucial role in the development of an efficient copper-catalyst system, where its thiol group serves as a strong anchoring site for metal coordination. By immobilizing copper onto cysteine-modified, polydopamine-coated magnetite particles, this advanced catalytic platform exhibits exceptional stability and catalytic activity. Chemical modification of the polydopamine (PDA) surface with cysteine enhances copper salt immobilization, leading to the formation of the Fe3O4@PDA-Cys@Cu platform. This system was evaluated in palladium-free, copper-catalyzed Sonogashira coupling reactions, effectively catalyzing the coupling of terminal acetylenes with aryl halides. Additionally, the Fe3O4@PDA-Cys@Cu platform was employed in click reactions, confirming the enhanced catalytic efficiency due to increased copper content. The reusability of the platform was further investigated, demonstrating improved performance, especially in recyclability tests in click reaction, making it a promising candidate for sustainable heterogeneous catalysis.

Bioorthogonal Chemistry: Enzyme Immune and Protein Capture for Enhanced LC-MS Bioanalysis.

Immunocapture liquid chromatography-mass spectrometry (IC-LC-MS) bioanalysis has become an indispensable technique across various scientific disciplines, ranging from drug discovery to clinical diagnostics. While traditional immunocapture techniques have proven to be effective, they often encounter limitations in sensitivity, specificity, and compatibility with MS analysis. Chemoenzymatic immunocapture and protein capture (IPC) offers a promising solution, combining the high specificity of antibodies or proteins with the versatility of enzymatic and chemical modifications. This Review explores the foundational principles of chemoenzymatic IPC and examines various modification strategies including bioorthogonal click-chemistry, enzymatic-tagging, and HaloTag/CLIP-tag. Recent advancements in chemoenzymatic IPC techniques have significantly expanded their applicability to a diverse range of biomolecules including small molecules, peptides, RNAs, and proteins. This Review focuses on improvements in analytical performance achieved through these innovative approaches. Moreover, we discuss the broad applications of chemoenzymatic immunocapture in drug discovery, clinical diagnostics, and environmental analysis and explore its potential for future advancements in bioanalysis. We propose a novel solid-phase chemoenzymatic IPC assay (SCEIA) that effectively utilizes bioorthogonal click chemistry and chemoenzymatic approaches for efficient IPC and target analyte release. In summary, chemoenzymatic IPC represents a transformative paradigm shift in IC-LC-MS bioanalysis. By overcoming the limitations of traditional IPC techniques, this approach paves the way for more robust, sensitive, and versatile analytical workflows.

Micro/Nano Hierarchical Dumbbell-like and Micropapillae Structure Improves Light Absorption and Facilitates Anti-icing/Deicing Performance.

The emergence of ice formation and accretion presents significant challenges, catalyzing an urgent need for clean and efficient anti-icing solutions. Solar energy, a powerful and sustainable resource, can be integrated with the micronano-structured superhydrophobic surface to enhance anti-icing and deicing performance through the solar photothermal effect, overcoming the limitations of a traditional superhydrophobic surface. Herein, inspired by bamboo and lotus leaves, a synergetic photothermal anti-icing superhydrophobic surface (PASS) has been developed. This was achieved through nanosecond laser ablation and chemical modification, resulting in a surface with remarkable superhydrophobic low adhesion (water contact angle >167°, rolling angle < 2°). The PASS notably extends the freezing time of water droplets to 1056 s and delays frost formation to 47 min at 60% humidity. Moreover, the surface retains its superhydrophobic properties after enduring several rigorous tests. Additionally, the photothermal conversion efficiency reaches up to 67.31%, and the temperature increases to 95.6 °C under 1.5 sun illumination for 600 s in ambient conditions (Tr = 7 °C). The ice melting time is only 120 s under 1 sun illumination at -15 °C. Consequently, the PASS sample stands as a preeminent strategy for anti-icing and deicing pursuits owing to its exceptional photothermal proficiency, superhydrophobicity, and enduring robustness.

Unveiling the Activity Origin of Electrochemical Oxygen Evolution on Heteroatom-Decorated Carbon Matrix.

Chemical modification via functional dopants in carbon materials holds great promise for elevating catalytic activity and stability. To gain comprehensive insights into the pivotal mechanisms and establish structure-performance relationships, especially concerning the roles of dopants, remains a pressing need. Herein, we employ computational simulations to unravel the catalytic function of heteroatoms in the acidic oxygen evolution reaction (OER), focusing on a physical model of high-electronegative F and N co-doped carbon matrix. Theoretical and experimental findings elucidate that the enhanced activity originates from the F and pyridinic-N (Py-N) species that achieve carbon activation. This activated carbon significantly lowers the conversion energy barrier from O* to OOH*, shifts the potential-limiting step from OOH* formation to O* generation, and ultimately optimizes the energy barrier of the potential-limiting step. This wok elucidates that the critical role of heteroatoms in catalyzing the reaction and unlocks the potential of carbon materials for acidic OER.

Deciphering the Cell Surface Sugar-Coating via Biochemical Pathways.

Cell surface components, specifically glycans, play a significant role in several biological functions like cell structure, crosstalk between cells, and eventual target recognition of the cells for therapeutics. The dense layer of glycans, i. e., glycocalyx, could differ in taxon, species, and cell type. Glycans are coupled with lipids and proteins to form glycolipids, glycoproteins, proteoglycans, and glycosylphosphatidylinositol-anchored proteins, making their study challenging. However, understanding glycosylation at the cellular level is vital for fundamental research and advancing glycan-targeted therapy. Among different pathways, metabolic glycan labelling uses the natural metabolic processes of the cell to introduce abiotic functionality into glycan residues. The Bertozzi group pioneered metabolic oligosaccharide engineering using glycan salvage pathways to convert monosaccharides with unnatural modifications. This eventually results in the probe becoming part of the complex cellular glycan structures via click chemistry using copper. On the other hand, the boronic acid-based probe can recognise carbohydrates in a single step without any chemical modification of the surface. This review discusses the significance of glycans as biomarkers for different diseases and the necessity to evaluate them in situ within the physiological environment. The review also discusses the prospect of this field and its potential applications.

Remediation of hexavalent chromium in water and soil by pristine and chemically modified pine barks: Effects and mechanisms

Chemical modification can greatly improve the adsorption performance of materials. In this study, pristine pine bark (PB) was modified by phosphoric acid (PA-PB), dodecyl trimethylammonium bromide (DTAB-PB) and cetyl trimethylammonium bromide (CTAB-PB) to test their influence on remediating hexavalent chromium [Cr(Ⅵ)] contamination in water and soil systems. Under the optimal experimental conditions in solution, the reduction/adsorption capacities and removal rates of Cr(Ⅵ) follow the order of CTAB-PB > PA-PB > DTAB-PB > PB, with CTAB-PB showing the highest capacity of 88.1 mg g−1. Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) indicated that adsorption coupled with reduction were the responsible mechanisms for Cr(Ⅵ) removal by pristine and modified PB, and modification with CTAB greatly improved Cr(Ⅵ) removal, especially the reduction of Cr(Ⅵ). When CTAB-PB and PB were applied in soil for a 30-day microcosm experiment, more than 93 % of Cr(Ⅵ) was converted into Cr(Ⅲ) at four different addition levels (2, 5, 10, and 15 wt%) with CTAB-PB exhibiting a faster immobilization rate than PB. In conclusion, CTAB-PB showed better performance than PB and is a promising material for the remediation of Cr(Ⅵ) contamination in water and soil.