China 
Africa 
Explore chapters and articles related to this topic
Impact of Physicochemical Properties on Dendrimer Pharmacokinetics and Biodistribution
Published in Delphine Felder-Flesch, Dendrimers in Nanomedicine, 2016
Orlagh Feeney, Suzanne M. Caliph, Christopher J. H. Porter, Lisa M. Kaminskas
In summary, the active or passive accumulation of dendrimers in cancerous tissue to deliver conjugated chemotherapeutics provides a means of circumventing toxicity issues associated with small molecule cytotoxic drugs. However, the targeting strategies employed are dependent on the surface chemistry, size and presence of targeting ligands. Increased plasma circulation times induced by polymeric surface coatings can result in improved tumor colocalization but steric effects may preclude efficient internalization of the dendrimer. On the other hand, surface decoration with targeting ligands may slow dendrimer ingress into the tumor mass, reducing efficacy. These passive and active targeting strategies must be balanced in order to maximize the tumoral uptake of dendrimers.
Plasma Surface Treatment to Enhance Adhesive Bonding
Published in A. Pizzi, K. L. Mittal, Handbook of Adhesive Technology, 2017
It has been established that for successful application of polymeric composite materials to form structural parts using adhesive bonding, they need to have special surface properties such as polarity and high surface free energy (SFE) [9]. A basic requirement for successful bonding is the spreading of the adhesive on the surface of the adherend or substrate [10]. This will occur if the SFE of the adhesive is lower than that of the adherend, but the typical values of SFE are 30–50 mJ/m2 for adhesives and about 12 mJ/m2 to about 70 mJ/m2 for polymers [11]. This shows that although these polymers have found wide suitability for high-end applications, they still have some limitations in achieving a good structural adhesive bond. Several conventional methods such as chemical treatment, thermal treatment, and mechanical treatment are used to modify polymeric surfaces, but they suffer from problems of uniformity, reproducibility, and cost-effectiveness. The need for adequate adhesion by activating the polymeric surface without affecting the bulk properties of the polymer has resulted in the development of plasma surface modification techniques [12], which offer a uniform, reproducible, economic, and environmentally friendly alternative [13]. It has been observed that the polar component of the SFE leading to increased total SFE of the polymer increases significantly due to generation of new functional groups as a result of surface oxidation by reactive species in the plasma [14]. The changes in the physicochemical characteristics and surface morphology of the polymer brought about by plasma result in strong adhesion [15].
Phototherapy Using Nanomaterials
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
A. N. Resmi, V. Nair Resmi, C. R. Rekha, V. Nair Lakshmi, Shaiju S. Nazeer, Ramapurath S. Jayasree
Biodegradable nanoparticles are made from polymers that degrade after PS release. Biodegradable polymer-based nanoparticles have gained a lot of attention because of their advantages in regulating drug release, flexibility in processes of material processing, less toxicity, and high drug loading [167]. The polymeric surface properties, morphologies, and structure can be designed to achieve the desired biocompatibility, regulate rate of degradation, and kinetics of drug release. Also, polymer’s chemical composition and structure can be adapted to fit photosensitizers with varying degrees of hydrophobicity, molecular weight, charge, and pH. Synthetic polymers, such as aliphatic polylactide (PLA), polyglycolide (PGA), and their copolymer polymer poly(d,l-lactide-co-glycolide) (PLGA), are also used as drug delivery carriers because of their favorable properties such as strong biocompatibility, biodegradability, bioresorbability, and mechanical power [168, 169]. For example, a photosensitizer meso-tetra(hydroxyphenyl)porphyrin (p-THPP) was encapsulated with submicronic nanoparticles of poly(d,l-lactide-co-glycolide) (50:50 and 75:25 PLGA) and poly(d,l-lactide) (PLA) with drug loading of up to 7% (m/m) using emulsification-diffusion technique. The photodynamic activity was evaluated on EMT-6 mammary tumor cells as compared to free p-THPP. Irrespective of the nature of the delivery system, the cell viability of the drug was concentration dependent. The photo induced cytotoxicity of the dye was strongly affected by the PDT parameters, such as drug concentration, light dose, drug–light time interval, and copolymer molar ratio. It was observed that the copolymer molar ratios influence the rate of carrier uptake and consequently, the intracellular drug concentration [169].
Environmental applications of nanocellulose scaffolded metal organic frameworks (MOFs@NC)
Published in Critical Reviews in Environmental Science and Technology, 2023
Jie Zhou, Mingyang Song, Xiaolei Hu, Wei-xian Zhang, Zilong Deng
Although a remarkable improvement in the absorption capacity of MOFs@NC was achieved by modifying the surface chemistry of MOFs, the homogeneous dispersion of MOFs in NC is still challenging due to the high surface energy of MOFs. Accordingly, polymeric surface coating at NC to boost the dispersion of MOFs has been reported. Polydopamine (PDA) was successfully coated on the surface of BNC, and subsequently UiO-66/PDA/BNC aerogel was prepared (Cui et al., 2020). UiO-66/PDA/BNC achieved excellent adsorption of both aspirin (149 mg/g) and tetracycline hydrochloride (TC) (184 mg/g), outperforming various reported materials. The adsorption of aspirin is mainly physical migration through weak intermolecular electrostatic and π-π interactions from aqueous phase to UiO incorporated aerogel. However, the adsorption of TC was mainly through chemical adsorption due to the possible formation of strong Zr-N coordination bonds. In another experiment, ZIF-8 embedded in a PDA-coated BNC pellicle (BNC@Dopa-ZIF) was proven for adsorption of iodine in water vapor and aqueous solutions with capacity values of 1.87 ± 0.18 g·g−1 and 1.31 ± 0.02 g·g−1, respectively (Au-Duong & Lee, 2018). Moreover, the iodine captured by BNC@Dopa-ZIF could be desorbed by ethanol extraction and photothermal irradiation.
Low-cost fabrication of flexible water-repellent film by spray coating of a hydrophobic nanoparticle dispersion
Published in Journal of Dispersion Science and Technology, 2020
Young-Sang Cho, Soyoung Nam, Sol Jeong, Young-Seok Kim
In this study, a low-cost fabrication method was developed to prepare flexible superhydrophobic films by spray coating a colloidal dispersion of hydrophobic silica nanoparticles. To induce the lotus effect, the surface roughness of the PDMS film was increased by transferring the surface protrusions of commercial paper to the polymeric surface by curing the PDMS monomer on the paper and subsequently removing the paper by detachment. The resulting microstructured PDMS-based flexible film was deposited with hydrophobic silica nanoparticles by spray coating to increase the contact angle of water droplets to approximately 150°. For the dispersion of hydrophobic nanoparticles, four silane or titanate coupling agents were used to modify the surface of hydrophilic silica nanopowder and their effects were compared on the basis of the contact angles of water droplets. In addition to the chemical structures of the surface-modifying agents, the effects of the amount of the coupling agents were also investigated to assess the degree of hydrophobicity of the water-repellent flexible films. The storage stability of the hydrophobic nanoparticles prepared with the coupling agents was also compared by observing the sedimentation behavior of the dispersions.
Improvement of adhesive bonding of polypropylene and maleic anhydride grafted polypropylene blends to aluminium by means of addition of cyclic butylene terephthalate
Published in The Journal of Adhesion, 2019
Victoria Astigarraga, Koldo Gondra, Ángel Valea, Goizane Pardo Aurrekoetxea
As the results of lap shear test have indicated, the compatibilized CBT+Cat/PP-g-MA/PP mixtures show better adhesion behavior in comparison with their antecessor binary blends. The characterization of the fracture surface exposed in Figure 11c, reveals a surface with peaks up to 15 μm that corresponds with a polymeric roughness of 3.9 μm. In the SEM micrographs of lap shear surface exposed in Figure 13a, it can be seen an almost completely surface covered by the polymer. Furthermore, the appearance of the polymeric surface is significantly different from the smooth surface of the polymer observed in the Figure 12. Higher magnification micrograph shows a fibrillar structure with many elliptic holes and pores into the polymers along the tensile shear direction. That implies a significant plastic deformation of the polymer that would indicate the presence of adhesion to the metal during the test that would have suffered a failure because of the cohesion of the polymer.[1]