Functional Surface Modification Research Articles

Biodegradable Inorganic Nanoparticles for Cancer Theranostics: Insights into the Degradation Behavior.

Inorganic nanoparticles as a versatile nanoplatform have been broadly applied in the diagnosis and treatment of cancers due to their inherent superior physicochemical properties (including magnetic, thermal, optical, and catalytic performance) and excellent functions (e.g., imaging, targeted delivery, and controlled release of drugs) through surface functional modification or ingredient dopant. However, in practical biological applications, inorganic nanomaterials are relatively difficult to degrade and excrete, which induces a long residence time in living organisms and thus may cause adverse effects, such as inflammation and tissue cysts. Therefore, the development of biodegradable inorganic nanomaterials is of great significance for their biomedical application. This Review will focus on the recent advances of degradable inorganic nanoparticles for cancer theranostics with highlight on the degradation mechanism, aiming to offer an in-depth understanding of degradation behavior and related biomedical applications. Finally, key challenges and guidelines will be discussed to explore biodegradable inorganic nanomaterials with minimized toxicity issues, facilitating their potential clinical translation in cancer diagnosis and treatment.

The effect of surface modification of PMMA/chitosan composites on improving adsorption properties for chelating Pb2+

Abstract As lead-containing products, such as lead batteries, are widely used, water pollution problems caused by Pb2+ show a significant threat to the ecosystem and human health. To overcome this serious problem, the modified poly(methyl methacrylate) (PMMA)/chitosan (CS) composites were prepared by adding CS into the PMMA matrix as functional filler and surface modification. The structure, thermal stability, size, morphology and adsorption properties of the modified PMMA/CS composites were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and inductively coupled plasma optical atomic emission spectrometry. The results indicated that the modified PMMA/CS composites had a uniform size of about 1 μm and showed quite good thermal stability. In addition, the Pb2+ removal of the modified PMMA/CS composite reached up to 98% when the initial Pb2+ concentrations are under 100 mg l−1. The results of the adsorption isotherms indicated that the Langmuir isotherm fits best to the experimental data when compared with the Freundlich isotherm and Temkin isotherm. All these results demonstrate that modified PMMA/CS has a good adsorption property and can be a promising adsorbent for chelating Pb2+.

Surface functional modification boosts the output of an evaporation-driven water flow nanogenerator

Harvesting environmental thermal energy from a natural evaporation process is a promising method for acquiring renewable and sustainable energy. Here, we present an evaporation-driven water flow nanogenerator based on a piece of flexible carbon nanoparticle film. The open-circuit voltage of one single-piece device can be tuned from − 3 to 3 V by manipulating the surface functional groups on the carbon nanoparticles. The effects of different modification molecules and solution concentrations were also investigated. By combining the modified carbon films with opposite surface charges, we enhanced the output of the generator to a maximum open-circuit voltage of 5 V and a short-circuit current of 1.5 μA with a film size of 5 cm × 5 cm. Furthermore, the device can be easily integrated with carbon nanotube-based supercapacitors (CNT-SCs) to assemble the energy-storing and energy-harvesting devices into a self-sustaining power system. The electrical output of the device can directly power a liquid crystal display in an ambient environment and a blue LED with help of self-charged built-in SCs. This eco-friendly device, with its low cost and simple fabrication, shows great potential for future clean energy utilization and for extending the field of portable electronics.

Spray-Assisted Coil-Globule Transition for Scalable Preparation of Water-Resistant CsPbBr3 @PMMA Perovskite Nanospheres with Application in Live Cell Imaging.

Despite their impressive optical properties, lead halide perovskite quantum dots (PQDs) have not realized their potential, especially in bioimaging applications, as they suffer from poor moisture and thermal stability, solvent incompatibility, and significant toxicity. Here, a spray-assisted coil-globule transition method for encapsulating CsPbBr3 (CPB) PQDs into poly(methyl methacrylate) (PMMA) polymer nanospheres is reported. Polyvinylpyrrolidone-capped CPB PQDs are synthesized via the ligand assisted reprecipitation method in dichloromethane. After dissolving PMMA, the above precursor solution is sprayed into petroleum ether under high pressure N2 . High-pressure nebulization restricts the interactions between PMMA polymer chains, resulting in the formation of ≈112 nm nanoscale composite spheres after a coil-globule transition. The CPB@PMMA nanospheres not only possess 73% quantum yields but retain 81% of fluorescence intensity after the exposure to water for over 80 days. Due to their confined size and biocompatible encapsulation, they are readily available for cellular uptake and exhibit no toxicity on live HeLa cells. Furthermore, the PMMA surface allows for functional surface modification, carrying the possibility of targeting specific biological species and processes.

From nanoengineering to nanomedicine: A facile route to enhance biocompatibility of graphene as a potential nano-carrier for targeted drug delivery using natural deep eutectic solvents

Graphene has attracted massive interest in numerous biomedical applications such as anti-cancer therapy, drug delivery, bio-imaging and gene delivery. Therefore, it is important to ensure that graphene is nontoxic, and that its cellular biological behavior is safe and biocompatible. Herein, a new route was used to enhance the biocompatibility of graphene, using several natural deep eutectic solvents (DESs) as functionalizing agents, owing to their capability to introduce various functional groups and surface modifications. Characterization of the physicochemical changes in DES-functionalized graphene were conducted by FE-SEM, FTIR, XRD, and Raman spectroscopy. There were considerable improvements in the cytotoxicity profile of DES-functionalized graphene compared to pristine graphene and oxidized graphene, as demonstrated by cell viability, cell cycle progression, and reactive oxygen species evaluation assays. We also studied the association between cellular toxicity of DES-functionalized graphene and their physicochemical properties. To the best of our knowledge, this is the first study on the cytotoxicity profile improvement of graphene using DESs as functionalizing agents, and its cellular biological behavior. The application of DESs as functionalizing agents, especially for DES choline chloride (ChCl):malonic acid (1:1), significantly reduced the cytotoxicity level of graphenes. DES ChCl:malonic acid (1:1) also demonstrated higher tamoxifen entrapment efficiency and loading capacity in comparison to the functionalization with DES ChCl:glucose (2:1), ChCl:fructose (2:1) and ChCl:sucrose (2:1). Therefore, DES ChCl:malonic acid (1:1) is considered the most promising nano-carrier for drug delivery applications, owing to its lower cytotoxicity and higher drug loading capacity.

Tracking self-assembly morphology of cationic peptide analogues using turbidimetric- potentiometric titration

Peptide amphiphiles are promising molecular materials for drug delivery systems and regenerative medicine through formation of well-ordered nanostructures. Rationally designed self-associating synthetic peptide analogues containing arginine (FEFEFRFR) and lysine (FEFEFKFK) were studied to understand the effect of pH and side chain interactions and its influence on the resulting nanostructure formation. Changes in structural conformation in bulk were followed by turbidimetric-potentiometric titrations with pH ranges from 4 to 11 and 4 to 12.6 for FEFEFKFK and FEFEFRFR respectively. Fourier Transform Infrared Spectroscopy (FTIR) was used to determine the secondary structure of the peptides while Field Emission Scanning Electron Microscopy (FE-SEM) was employed to study the morphology and dimension of higher order structures at various pH. Turbidity results showed that both FEFEFKFK and FEFEFRFR displayed higher turbidity level when their side chains were neutralized, in which FEFEFRFR showed higher turbidity level when arginine was neutralized. Both peptides exhibited similar self-assembly behavior in solution which mainly adopted antiparallel β-sheets conformation with spherical structures of different micro-metre size when there is a net charge of +2 or -2. FEFEFKFK was also found to form concaved disks and beads-on-a-string arrangement at pH 4. Both the peptide analogues were capable of forming smaller aggregates in a network of spherical structure at nanoscale when the net charge was near zero. This study ultimately provides a better understanding of predicting morphology and size of surface functional modification of self-assembled polypeptides.

PEGylated graphene oxide-mediated quercetin-modified collagen hybrid scaffold for enhancement of MSCs differentiation potential and diabetic wound healing.

Nanoscale delivery based on polyethylene glycol (PEG)ylated graphene oxide (GO-PEG) merits attention for biomedical applications owing to its functional surface modification, superior solubility/biocompatibility and controllable drug release capability. However, impaired skin regeneration in applications of these fascinating nanomaterials in diabetes is still limited, and critical issues need to be addressed regarding insufficient collagen hyperplasia and inadequate blood supply. Therefore, a high-performance tissue engineering scaffold with biocompatible and biodegradable properties is essential for diabetic wound healing. Natural and artificial acellular dermal matrix (ADM) scaffolds with spatially organized collagen fibers can provide a suitable architecture and environment for cell attachment and proliferation. Here, a novel collagen-nanomaterial-drug hybrid scaffold was constructed from GO-PEG-mediated quercetin (GO-PEG/Que)-modified ADM (ADM-GO-PEG/Que). The resulting unique and versatile hybrid scaffold exhibited multiple advantages, including the following: a biocompatible, cell-adhesive surface for accelerating mesenchymal stem cell (MSC) attachment and proliferation; superior stability and adjustability of the conduction potential of quercetin for inducing the differentiation of MSCs into adipocytes and osteoblasts; and a biodegradable nanofiber interface for promoting collagen deposition and angiogenesis in diabetic wound repair. This study provides new prospects for the design of innovative GO-PEG-based collagen hybrid scaffolds for application in efficient therapeutic drug delivery, stem cell-based therapies, tissue engineering and regenerative medicine.

Glomerular Filtration Range (eGFR) and hematological changes during 2012 Comandos Special Operations Course

Introduction: It is well known that exercise induces changes in leukocyte redistribution with modification of phenotype surface expression, functionality and renal function. An exercise-induced increase of a given hematologic biomarker could be interpreted as signal of immune suppression or muscle damage in response to physical activity, which can be used as a clinical or physiological biomarker to control overtraining or overreaching in Special Operations Courses. The purpose of this study aimed to evaluate the effects of military training on the following variables: Leucocytes (WBC), Lymphocytes (LIN), Neutrophils (NEU), Hemoglobin (Hb), Hematocrit (Hct), Mean Corpuscular Volume (MCV), Red Blood Cell Distribution (RDW) and Renal Function (eGFR) during the 2012 Comandos Special Operation Course.

Surface functional modification of ultrahigh molecular weight polyethylene fiber by atom transfer radical polymerization

In order to improve the bonding between Ultra High Molecular Weight Polyethylene fiber (UHMWPE) and resin, the fiber surface need to be modified with functional groups. In the paper, the UHMWPE fiber was chlorinated by NaClO and then grafted with 2-hydroxyethyl methacrylate by Atom Transfer Radical Polymerization. After chlorination and grafting, the surface tensions of fibers achieved to 36.5mN/m and 49.5mN/m, respectively. FTIR-ATR and XPS confirmed that the surface of UHMWPE fiber has been functional modified by hydroxyl and ester function of grafted polyhydroxyethylmethacrylate. Further, it can be seen from SEM that the surface of functional modified UHMWPE fiber was not damaged. Compared to unmodified UHMWPE fiber, the mechanical property of functional modified UHMWPE fiber and epoxy resin composite was greatly improved.

Surface functionalization of polyamide fiber via dopamine polymerization

The oxidative polymerization of dopamine for the functional surface modification of textile fibers has drawn great attention. In this work, the functionalization of polyamide fiber via dopamine polymerization was studied with the aim of the fabrication of hydrophilic and antistatic surface. The conditions of dopamine application were first discussed in the absence of specific oxidants in terms of the apparent color depth of polyamide fiber. Dopamine concentration, pH and time were found to exert great impact on color depth. The highest color depth was achieved at pH 8.5. In the process of modification, polydopamine was deposited onto the surface of polyamide fiber. The modified polyamide fiber displayed a yellowish brown color with excellent wash and light color fastness, and exhibited good hydrophilic, UV protection and antistatic effects. A disadvantage of the present approach was the slow rate of dopamine polymerization and functionalization.

Amphiphilic polymer layer – Model cell membrane interaction studied by QCM and AFM

The benefit gained by application of nanostructured drug delivery systems is highly influenced by their possible transport in the body. The affinity to cell membrane is a crucial parameter to be optimized by tuning the surface properties of nanoparticles (NPs). Poly(lactic/glycolic acid) (PLGA) NPs designed for drug delivery were stabilized with three different Pluronics (103, 105 and 108) as well as an amphiphilic monoalkyl hyperbranched polyglycerol (C18-HbPG). Their interaction with lipid bilayer was investigated in two types of arrangements using liposomes and polymeric adsorbed layer, while in the other model polymer stabilized PLGA NPs and supported lipid bilayer (SLB) were applied. Degree of adhesion of liposomes and PLGA NPs were characterized by quartz crystal microbalance (QCM) measurements in combination with the visual analysis of the surfaces by atomic force microscopy (AFM). The comparison of the various polymer coatings led to the conclusion that C18-HbPG resulted in the highest membrane affinity, followed by Pluronic105 with medium polarity within the Pluronic series. This finding further supports the results obtained previously regarding colloid stabilization efficacy (Kasza, 2017) that amphiphilic hyperbranched polyglycerol is an ideal alternative to Pluronics in the functional surface modification of drug carrier NPs.

Application of Organic Monolithic Materials to Enantioseparation in Capillary Separation Techniques.

This review article is primarily focused on the state-of-the-art of enantioseparations on organic monolithic materials. The article gives an overview of the chiral stationary phases and its application in capillary electrochromatography (CEC), and capillary- and nano-liquid chromatography (cLC and nLC). Since thousands of publications have been emerged from 2000's and citing all these papers would extend the scope of this review; then, recent developments from last 10 years (2006 to 2016) will be mentioned. Mostly, stationary phases based on copolymers obtained from chiral functional monomers and surface modifications of organic monoliths with chiral ligands will be discussed. The effective application of these chiral separation methodologies in several analysis areas will be also included.

Systemic and immunotoxicity of pristine and PEGylated multi-walled carbon nanotubes in an intravenous 28 days repeated dose toxicity study.

The numerous increasing use of carbon nanotubes (CNTs) derived from nanotechnology has raised concerns about their biosafety and potential toxicity. CNTs cause immunologic dysfunction and limit the application of CNTs in biomedicine. The immunological responses induced by pristine multi-walled carbon nanotubes (p-MWCNTs) and PEGylated multi-walled carbon nanotubes (MWCNTs-PEG) on BALB/c mice via an intravenous administration were investigated. The results reflect that the p-MWCNTs induced significant increases in spleen, thymus, and lung weight. Mice treated with p-MWCNTs showed altered lymphocyte populations (CD3+, CD4+, CD8+, and CD19+) in peripheral blood and increased serum IgM and IgG levels, and splenic macrophage ultrastructure indicated mitochondria swelling. p-MWCNTs inhibited humoral and cellular immunity function and were associated with decreased immune responses against sheep erythrocytes and serum hemolysis level. Natural killer (NK) activity was not modified by two types of MWCNTs. In comparison with two types of MWCNTs, for a same dose, p-MWCNTs caused higher levels of inflammation and immunosuppression than MWCNTs-PEG. The results of immunological function suggested that after intravenous administration with p-MWCNTs caused more damage to systemic immunity than MWCNTs-PEG. Here, we demonstrated that a surface functional modification on MWCNTs reduces their immune perturbations in vivo. The chemistry-modified MWCNTs change their preferred immune response in vivo and reduce the immunotoxicity of p-MWCNTs.

Functional surface modification of PVDF membrane for chemical pulse cleaning

Membrane fouling research has become a focus, significant amount of work has been dedicated to membrane surface modification for improving anti-fouling performance. However, fouling still occurs, which means cleaning is inevitable. The present method is mainly inefficient offline chemical cleaning using specialized chemicals. So we put forward a new method of online chemical pulse cleaning accomplished by designing a kind of pH responsive molecular structure on the PVDF membrane surface, which was prepared through wet chemical strategy, under basic conditions, by using diethylenetriamine (DETA) as carrier of amino groups, and then these amino groups were activated with maleic anhydride (MAH) in order to introduce carboxyl groups. The modified membranes were characterized by attenuated total reflectance-Fourier transform infrared spectra (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), mechanical property, streaming potential and contact angle measurements. The results of water flux and swelling degree revealed the flexible chains had excellent pH-responsive. And the modified membranes showed outstanding anti-pollution capability and online chemical pulse cleaning effect when used to separate soybean oil-in-water emulsion and BSA solution. Meanwhile, the flux recovery rates after five times circulation could still reach 90.3% and 95.2%, respectively. This study provides a new way for building antifouling surface and improving cleaning efficiency.

Aramid–multiwalled carbon nanotube nanocomposites: effect of compatibilization through oligomer wrapping of the nanotubes

AbstractAramid–multiwalled carbon nanotube (MWCNT) nanocomposites with different CNT loadings were prepared by the solution‐blending technique. Aramid oligomeric chains having reactive amine end‐groups were covalently grafted and wrapped over the surface of acid‐functionalized MWCNTs. The presence of functional groups and surface modification of MWCNTs were studied using Raman, Fourier transform infrared and X‐ray photoelectron spectroscopic and transmission/scanning electron microscopic techniques. Addition of these MWCNTs resulted in a homogeneous dispersion throughout the aramid matrix. Dynamic mechanical thermal analysis showed an increase in the storage modulus and the glass transition temperature involved with α‐relaxations on CNT loading. The coefficient of thermal expansion (CTE) of aramid was reduced on loading with such CNTs. Strong interfacial interactions of the matrix with the surface‐modified CNTs reduced the stress‐transfer problem in the composite material and resulted in higher modulus of 4.26 GPa and a glass transition temperature of 338.5 °C, whereas the CTE was reduced to 101.8 ppm °C−1 on addition of only 2.5 wt% CNTs in the aramid matrix. © 2016 Society of Chemical Industry

Synthesis of nano CaCO3/acrylic co‐polymer latex composites for interior decorative paints

CaCO3 nanoparticles were synthesised in patented solution spray reactor system using non‐ionic Tween‐80 surfactant as template. Design of solution spray reactor permits the intimate thin film contact between the highly atomized precursor and precipitant solutions to control the CaCO3 size in 25–90 nm range. CaCO3 nanoparticles were surface modified with γ‐methacryloxypropyltrimethoxysilane (GMPTS) in order to improve the compatibility with polymer matrix. CaCO3/acrylic co‐polymer latex nanocomposites were prepared by in situ emulsion polymerization with 0.5‐2.5 wt % loadings of nanoCaCO3. Functional group, surface modification, crystal phase, size and morphology of CaCO3 nanoparticles were determined by their FTIR, XRD and FESEM analysis. DSC and TGA analysis was performed to establish the rise in thermal stability of latex nanocomposites due to inclusion of nanoCaCO3, while its ultrafine dispersion in polymer matrix was confirmed by FESEM analysis of latex nanocomposite films. Interior waterborne decorative paints were formulated using CaCO3/acrylic co‐polymer latex nanocomposites as binder. Overall three fold rise in performance of latex nanocomposite paint over that of clear latex paint in terms of wet scrub, mar and stain resistance, cross cut adhesion and pencil hardness was observed which implies commercial viability of use of surface modified nanoCaCO3. POLYM. COMPOS., 39:1350–1360, 2018. © 2016 Society of Plastics Engineers

Functional Processing and Surface Modification of Nuclear Engineering Articles

Methods for depositing functional and protective coatings on articles used in the nuclear engineering and for general industrial purposes that have been developed at VNIINM are described. The methods and their advantages are examined and applications are substantiated. Examples of the adoption of the technologies described are presented.

FACILE SYNTHESIS OF Pt-/Pd-MODIFIED NiTi ELECTRODE WITH SUPERIOR ELECTRO-CATALYTIC ACTIVITIES TOWARD METHANOL, ETHANOL AND ETHYLENE GLYCOL OXIDATION

Surface functional modification of NiTi electrode with noble Pt and Pd metal has been successfully carried out by simple and cost effective electro-spark deposition technique (ESD). Thin-film X-ray diffraction (TF-XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and cyclic voltammetry (CV) have been carried out in order to investigate the structure, morphology, chemical composition and electrochemical behavior of the modified electrode surface. The modified Pt/NiTi and Pd/NiTi electrode surface exhibit a circular splash pattern with a tiny amount of Pt ([Formula: see text]5.30 at.% Pt) and Pd ([Formula: see text]5.71 at.% Pd) existence. The electrochemical results demonstrate that the Pt/NiTi and Pd/NiTi electrode possess an improved electro-catalytic activities toward methanol (MeOH), ethanol (EtOH) and ethylene glycol (EG) oxidation in alkaline media in comparison with the bare NiTi electrode. In acidic environments, the Pt/NiTi electrode exhibits even much better catalytic activities than the pure Pt sheet electrode due to the bi-functional mechanism. In the same way, the electro-catalytic activity of the modified Pd/NiTi electrode is also slightly larger than that of the pure Pd sheet electrode in alkaline environment. The electro-spark surface modification approach is rapid and environmentally-benign, being attractive to widen the application of traditional surface modification technique in the field of material surface/interface design and functionalization.

Surface Functional Modification of Graphene and Graphene Oxide

Surface Functional Modification of Graphene and Graphene Oxide

Mitophagy induced by nanoparticle–peptide conjugates enabling an alternative intracellular trafficking route

The intracellular behaviors of nanoparticles are fundamentally important for the evaluation of their biosafety and the designs of nano carrier-assisted drug delivery with high therapeutic efficacy. It is still in a great need to discover how functionalized nanoparticles are transported inside the cells, for instance, in a complicated fashion of translocation between different types of cell organelles. Here we report a new understanding of the interactions between nanoparticles and cells by the development of polyoxometalates nanoparticle–peptide conjugates and investigation of their intracellular trafficking behaviors. The as-prepared nanoparticles are featured with a unique combination of fluorescence and high contrast for synchrotron X-ray-based imaging. Functional surface modification with peptides facilitates effective delivery of the nanoparticles onto the target organelle (mitochondria) and subsequent intracellular trafficking in a dynamic mode. Interestingly, our experimental results have revealed that autophagy of mitochondria (mitophagy) can be induced by NP-peptide as a cellular response for recycling the damaged organelles, through molecular mediation associated with the change of mitochondrial membrane potential. The biological effects induced by NP-peptide reciprocally affect the distribution patterns and fates of nanoparticles in the cell metabolism by providing an alternative route of intracellular trafficking. The new understanding of the mutual activities between nanoparticles and cells will enrich our approaches in the development of nanobiotechnology and nano-medicine for disease treatments.