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Drug Nanocrystals
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Mayank Singhal, Jouni Hirvonen, Leena Peltonen
In the future, thus, building up and using of the nanocrystals might be suitable for combining drug containing fluorescent, magnetic, or radioactive cores with fluorescent, magnetic, or radioactive shells that could be detected with fluorescence microscopy, magnetic resonance imaging (MRI), or single-photon emission computed tomography. These examples are based on particles that report data for diagnosis to a physician (e.g., images of tissue, local analyte concentrations) and can, also, initiate the drug treatment, for example, in tumor therapy. However, as of today, the clinical use of theranostic nanocrystals is very little, if non-existent. There might be potential problems like cytotoxic effects of the nanocrystals and their core and surface contents. The main hurdle remaining is, however, the poorly controlled targeting of the nanocrystals—a problem intensified by the fast dissolution of the nanocrystalline core particles. Nanocrystals might enable, for example, passive tumor targeting governed by the small size and the enhanced permeation and retention (EPR) effect. However, passive targeting is oftentimes not sufficient and may involve significant side effects, such as nanocrystals clearance into the immune system or accumulation into the liver and spleen. Active targeting of nanocrystals by ligand specific reactions would, perhaps, increase the applicability of nanocrystalline formulations to new levels in the future.
Nanoscale Electrocrystallization
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2019
In the case of DC, the randomly oriented nanocrystals are formed on the entire electrode surface, at the side where the electrochemical reaction occurs (e.g., the anode in the case of the donor molecule, Figure 19.3a), whereas when using AC, the nanocrystal is selectively grown only on the portion where the two electrodes are closest to each other; further, the two electrodes are connected by nanocrystals. The nanocrystals thus obtained can be observed by scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM), and the crystal structure can be determined by analyzing the selected area electron diffraction (SAED) pattern. Analysis of the diffraction spot revealed that a π-stack was formed along the long-axis direction of the nanocrystal in most cases; moreover, the nanocrystal had high conductivity in the long-axis direction.
Advances in Nanotechnology of Food Materials for Food and Non-Food Applications
Published in Dennis R. Heldman, Daryl B. Lund, Cristina M. Sabliov, Handbook of Food Engineering, 2018
Rohollah Sadeghi, Thanida Chuacharoen, Cristina M. Sabliov, Carmen I. Moraru, Mahsan Karimi, Jozef L. Kokini
Nanocrystals are unique nanoparticles since they consist of a bioactive compound with a surfactant, whereas other nanodelivery carriers consist of a particle as nanocarrier with either dispersed or encapsulated compounds (Pawar et al., 2014). Nanocrystal systems have been shown to have different physical properties compared to the bulk materials. For example, increasing solubility of poorly soluble drugs can be achieved by decreasing particle size (Junghanns and Müller, 2008). In food applications, nanocrystals such as chitin have been widely used as an emulsifier, as when it is adsorbed at the oil–water interface, chitin nanocrystals improve the stability of the emulsions over 1 month (Tzoumaki et al., 2011). Alternatively, the transformation of a nanosuspension into nanocrystals can be beneficial for the formulation of solid nutraceutical forms such as pellets (Mitri et al., 2011b).
High-efficient removal of Cu(II) using biochar/ZnS composite: optimized by response surface methodology
Published in Journal of Dispersion Science and Technology, 2023
Lili Yan, Siyu Jiang, Pinhua Rao, Guanghui Li, Zongdi Hao, Lei He, Shanliang Liu, Guofeng Shang
Semiconductor nanocrystals (NCS) are widely used for adsorption, catalysis, and sensing, because of its large specific surface area and reaction activity. The use of ZnS NCS to reduce the HMs ion concentration from contaminated water has been previously reported.[16,17] Although it can be an ideal choice for HMs removal, a carrier is needed owing to its small size and difficulty in recycling.[18] Thus, combing biochar with NCS is a good alternative, which could disperse the NCS and remove pollutants. However, several factors can affect the removal of HMs in water environment, it is essential to select a suitable approach to evaluate the influence of these factors and their interaction on the removal performance.[19] Response surface method (RSM) is a mathematical-statistical design that could be used to obtain a best condition in the system of multiple factors.[20] Box Behnken design (BBD) is a type of RSM that could be applied to ascertain the influence of experimental variables on the response value and to clarify the relationship between them. Thus, an RSM scheme could be developed to achieve an optimum removal of HMs.
Blue perovskite light-emitting diodes (LEDs): A minireview
Published in Instrumentation Science & Technology, 2020
A large number of the atoms of the nanocrystal are located on the surface due to the high surface-to-volume ratio, which determines that the surface conditions have a great influence on its performance. Therefore, in order to improve the stability and efficiency of perovskite-type nanocrystals, surface ligand passivation has been shown to be a common technique, including the use of short-chain ligands,[15] bidentate ligands,[43] zwitterions capping termination ligands,[44] branched termination ligands[45] and phosphorus ligands.[46,47]
Correlated Debye model for atomic motions in metal nanocrystals
Published in Philosophical Magazine, 2018
Nanocrystals are quite different, and their finiteness makes phonon confinement (max allowed vibration wavelength) and surface vibration modes important. The VDOS of a finite body must account for the additional modes arising from surfaces – in terms of limiting planes, edges and even corner points – and include the appropriate wavelength cut-off for the size and shape of the domain. In turn this influences the way the DW coefficient should be calculated. After the early studies of Bolt, Maa and Roe around 1940 [25–27] much of the theory has been reviewed by Schoening [28] and by Urban [29]: the following results rely directly on the cited literature.