Surface-modified Nanomaterials Research Articles

Grafting tetradecyl methacrylate-carbic anhydride (CA) or tetradecyl methacrylate-tetrahydrophthalic anhydride (THPA) co-polymers onto surface-modified nano silica to develop of pour point depressants for diesel

Polymers with alkyl methacrylate as structural unit can significantly improve cold flow properties of diesel. Grafting polymers onto surface-modified nanomaterials can further enhance the low temperature fluidity of diesel. In this study, two molecules containing the structure of dicarboxylic anhydride were used as structural unit with tetradecyl methacrylate to synthesise the polymer pour point depressant (PPD). These polymer PPDs achieved excellent depressive effects, in particular, 1500 ppm of tetradecyl methacrylate–carbic anhydride (9:1) reduced the cold filter plugging point (CFPP) and solid point (SP) of diesel by 8 and 18 ℃, respectively. To further enhance the low-temperature fluidity properties of diesel, silane coupling agents were used to surface-modify nano silica, and then polymers were chemically grafted onto the surface-modified nano silica to prepare the nano PPDs. The well-dispersed nano PDDs achieved higher depressive effects than polymer PPDs on diesel. The diesel treated with 1500 ppm of tetradecyl methacrylate–carbic anhydride–surface modified nano silica (9:1:1) showed a decrease in CFPP and SP of 14 ℃ and 21 ℃, respectively. Transmission electron microscope was used to characterise the morphology and particle size of nano silica before and after surface modification and chemical grafting. The structural features of polymer PPDs and nano PPDs were analysed using fourier transform infrared spectroscopy, gel permeation chromatography and proton nuclear magnetic resonance. Finally, the n-alkane crystallisation habit and wax crystal growth habit of pure diesel and diesel treated with polymer and nano PPDs during cooling process were characterized using differential scanning calorimetry, polarising optical microscopy and rheometry. The effects of polymer and nano PPDs on the nucleation and growth patterns of n-alkanes in diesel were presented and the possible mechanism was inferred.

Chemokine-targeted nanoparticles: stimulation of the immune system in cancer immunotherapy

Surgery, chemotherapy, radiation therapy, and immunotherapy are potential therapeutic choices for many malignant and metastatic cancers. Despite adverse side effects and pain, surgery and chemotherapy continue to be the most common cancer treatments. However, patients treated with immunotherapy had better cancer control than those who got other treatments. There are two methods to activate immunological pathways: systemically and locally. To modify the tumor microenvironment (TME), the former uses systemic cytokine/chemokine (CK) delivery, whilst the latter uses immunological checkpoints or small molecule inhibitors. Organic and inorganic nanomaterials (NMs) enhanced the efficacy of cancer immunotherapy. NMs can transmit drugs, peptides, antigens, antibodies, whole cell membranes, etc. Surface-modified NMs precisely target and enter the tissues. The inner core of surface-modified NMs is composed of chemicals with limited bioavailability and biocompatibility, resulting in prolonged blood retention and decreased renal clearance. These platforms hinder or prevent many immune cell activities and modify the TME, enhancing the efficiency of cancer immunotherapy. By inhibiting CK/CK receptor signaling, cell migration and other immune responses could be controlled. Developing CK-targeted nanoparticles (NPs) that inhibit CK signaling or take advantage of the ligand-receptor connection is possible. Surface chemical modification of NMs with CKs or specific peptides has several medicinal applications, including tissue-specific drug delivery and limited cell migration in cancer-afflicted conditions. This review covers current developments in the role of different groups of CK-loaded NP in tumor therapy targeting immune cells and cancer. It also covers the role of NP targeting CK signaling which aids in immunogenic cell death (ICD) and induction of antitumor immunity. In addition, CK gene silencing and its capacity to prevent cancer metastasis as well as inhibition of immune cell migration to modulate the TME are discussed.

Surface modified nanoparticles and their applications for enantioselective detection, analysis, and separation of various chiral compounds.

The development of efficient enantioselective detection, analysis, and separation relies significantly on molecular interaction. In the scale of molecular interaction, nanomaterials have a significant influence on the performance of enantioselective recognitions. The use of nanomaterials for enantioselective recognition involved synthesizing new materials and immobilization techniques to produce various surface-modified nanoparticles that are either encapsulated or attached to surfaces, as well as layers and coatings. The combination of surface-modified nanomaterials and chiral selectors can improve enantioselective recognition. This review aims to offer engagement insights into the production and application of surface-modified nanomaterials to achieve sensitive and selective detection, better chiral analysis, and separation of numerous chiral compounds.

Nanotechnology- A ray of hope for heavy metals removal

Environmental effects of heavy metal pollution are considered as a widespread problem throughout the world, as it jeopardizes human health and also reduces the sustainability of a cleaner environment. Removal of such noxious pollutants from wastewater is pivotal because it provides a propitious solution for a cleaner environment and water scarcity. Adsorption treatment plays a significant role in water remediation due to its potent treatment and low cost of adsorbents. In the last two decades, researchers have been highly focused on the modification of adsorption treatment by functionalized and surface-modified nanomaterials which has spurred intense research. The characteristics of nano adsorbents attract global scientists as it is also economically viable. This review shines its light on the functionalized nanomaterials application for heavy metals removal from wastewater and also highlights the importance of regeneration of nanomaterials in the view of visualizing the economic aspects along with a cleaner environment. The review also focused on the proper disposal of nanomaterials with crucial issues that persist in the adsorption process and also emphasize future research modification at a large-scale application in industries.

Theoretical investigation of emodin conjugated doped B12N12 nanocage by means of DFT, QTAIM and PCM analysis

The surface-modified nanomaterials are considered effective drug carriers due to their high electronic sensitivity and reactivity towards various drug molecules. In this work, we have modified B12N12 nanocage by doping metal atoms (Al and Ga) to form AlB11N12 and GaB11N12 nanocages, and deeply scrutinized the interactions of these nanocages towards emodin (ED) drug via DFT calculations. Our calculations demonstrated that AlB11N12 and GaB11N12 show high sensitivity and reactivity towards the ED than B12N12 in both gas and solvent media. ED interacts with AlB11N12 and GaB11N12 in gas media with energies −46.69 and −51.29 kcal/mol and in solvent media with −57.50 and −47.05 kcal/mol whereas the interaction energies of ED/B12N12 system are found about −22.48 and −24.68 kcal/mol in gas and water media respectively. The adsorption process significantly effects on the HOMO and LUMO levels which leads to reduction of Eg of ED/AlB11N12 and ED/GaB11N12 approximately 42.48% and 52.03%. Thus, the electrical conductivity greatly enhanced due to the reduction of Eg which can produce electrical signal. This phenomenon implies that AlB11N12 and GaB11N12 could be used as promising electronic drug sensor for ED. Furthermore, QTAIM and RDG analysis also indicate the strong hydrogen-bonded interaction between ED and both AlB11N12, and GaB11N12. • Pure, Al and Ga doped B 12 N 12 nanocages are studied to adsorb Emodin (ED) drug. • Favorable interaction is observed when ED adsorbed on doped B 12 N 12 nanocages. • Sensitivity is understood by the significant reduction of the HOMO-LUMO gap. • QTAIM and RDG analyses reveal the favorable intermolecular interactions. • Water solubility effects on ED drug are studied by using solvation energy.

The properties of nano-CaCO3/nano-ZnO/SBR composite-modified asphalt

Abstract To solve the problem of the pavement being aged due to the influence of temperature, light and other environmental factors are brought in service. Nano-CaCO3 surface was activated by 6% KH-550, and nano-ZnO surface was activated by 6% aluminate. Nano-CaCO3/nano-ZnO/SBR composite-modified asphalt was prepared. The optimum proportion of composite-modified asphalt was determined by orthogonal test. The influence of modifiers on asphalt pavement performance was comprehensively studied. The microstructure of composite-modified asphalt was characterized by scanning electron microscopy and infrared spectroscopy. The mechanism of composite-modified asphalt was analyzed. The results show that the optimum combination of composite-modified asphalt is 4% nano-CaCO3 + 5% nano-ZnO + 4% SBR, the aging performance of the composite-modified asphalt is reduced by 6.9%, and the viscosity is increased by 14.6–23.1%. The complex shear modulus is increased by 24.1% at 82°C, the stiffness modulus is decreased, on average, by 21.1%. and the creep curve slope is increased by 9% on average. In the meantime, during the preparation process of composite-modified asphalt, it mainly occurred due to chemical reaction with surface-modified nanomaterials and physical change with SBR polymer materials.

SERS based sensor for mycotoxins detection: Challenges and improvements

Surface-enhanced Raman spectroscopy (SERS) has become a growing ultrasensitive analytical technique to quantify toxic molecules in foodstuffs. Monitoring the levels of chemical contaminants not only ensures food security but also offers a guideline on the production, processing, and risk analysis of consumer’s health protection. The objective of this study was to point out the possible challenges associated with the detection of mycotoxins in foodstuffs. Herein, we have discussed briefly as to selectivity, accuracy, precision, robustness, ruggedness, non-specific adsorption (NSA), cross-reactivity (for both label-free and the target analyte capture approaches like the application of antibody, aptamer, molecularly imprinted polymer (MIP), linear polymer affinity agents and/or specific surface-modified nanomaterials) and their potential solution.

Computer-aided design of carbon nanotubes with the desired bioactivity and safety profiles

Growing experimental evidences suggest the existence of direct relationships between the surface chemistry of nanomaterials and their biological effects. Herein, we have employed computational approaches to design a set of biologically active carbon nanotubes (CNTs) with controlled protein binding and cytotoxicity. Quantitative structure–activity relationship (QSAR) models were built and validated using a dataset of 83 surface-modified CNTs. A subset of a combinatorial virtual library of 240 000 ligands potentially attachable to CNTs was selected to include molecules that were within the chemical similarity threshold with respect to the modeling set compounds. QSAR models were then employed to virtually screen this subset and prioritize CNTs for chemical synthesis and biological evaluation. Ten putatively active and 10 putatively inactive CNTs decorated with the ligands prioritized by virtual screening for either protein-binding or cytotoxicity assay were synthesized and tested. We found that all 10 putatively inactive and 7 of 10 putatively active CNTs were confirmed in the protein-binding assay, whereas all 10 putatively inactive and 6 of 10 putatively active CNTs were confirmed in the cytotoxicity assay. This proof-of-concept study shows that computational models can be employed to guide the design of surface-modified nanomaterials with the desired biological and safety profiles.

Aqueous stability and mobility of C60 complexed by sodium dodecyl benzene sulfonate surfactant

Surfactant complexation may have significant effects on the environmental behavior of nano-particles. In order to understand the ecological exposure of nano-materials, it is important to determine the stability and mobility of surfactant-complexed nano-materials in aqueous systems. In this study, the aggregation and transport of C60 complexed by the surfactant sodium dodecyl benzene sulfonate (SDBS) were investigated. It was found that SDBS-complexed C60 had a ζ-potential of −49.5mV under near-neutral pH conditions and remained stable during an aging period of 15days. It had a critical coagulation concentration of 550mmol/L for NaCl, which was higher than common natural colloids and many kinds of raw nano-materials, and was comparable to those of many kinds of surface-modified nano-materials. SDBS enhanced the stability of C60 colloid; however, at the same time, it also enhanced the colloidal particle aggregation rate. Much higher mobility was found for SDBS-complexed C60 than C60 colloid. Increase in ionic strength, Ca2+ concentration or Al3+ concentration decreased the mobility. In general, SDBS-complexed C60 had high stability and mobility.

A New Solid‐State pH Sensor and Its Application in the Determination of Amino on Surface Modified Nanomaterials

A new pH sensor suitable for determination of amino groups on surface modified nanomaterials (SMNs) is reported. The sensor has been constructed based on a poly 8‐hydroxyquinoline‐5‐sulfonic acid (HQS) thin film that was electrochemically deposited onto a Pt disc electrode previously modified with Pt nanoparticles. The poly HQS film was deposited from HAc‐NaAc solution containing HQS monomer by cycling the potential between 0.4 V and 1.4 V. The emf signal was linear over the pH range of 1.3 to 13.4 with a super Nernstian slope of 62.6 mV/pH unit. Response time ranged from several sec at pH around 7 up to 1 min at pH 13.4. The performance of the pH sensor was examined by measuring organic acid/amine and amino groups on surface modified nanomaterials samples.