scholarly journals Nanofluid Dynamics of Flexible Polymeric Nanoparticles Under Wall Confinement

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Samaneh Farokhirad ◽  
N. Ramakrishnan ◽  
David M. Eckmann ◽  
Portonovo S. Ayyaswamy ◽  
Ravi Radhakrishnan
Keyword(s):  
Brownian Motion ◽  
Polymer Chain ◽  
Brownian Dynamics ◽  
Temporal Dynamics ◽  
Polymeric Nanoparticles ◽  
Hydrodynamic Forces ◽  
Hydrodynamic Interactions ◽  
Polymeric Nanoparticle ◽  
Fluid Media ◽  
Dynamics Method

Describing the hydrodynamics of nanoparticles in fluid media poses interesting challenges due to the coupling between the Brownian and hydrodynamic forces at the nanoscale. We focus on multiscale formulations of Brownian motion and hydrodynamic interactions (HI) of a single flexible polymeric nanoparticle in confining flows using the Brownian Dynamics method. The nanoparticle is modeled as a self-avoiding freely jointed polymer chain that is subject to Brownian forces, hydrodynamics forces, and repulsive interactions with the confining wall. To accommodate the effect of the wall, the hydrodynamic lift due to the wall is included in the mobility of a bead of the polymer chain which depends on its proximity to the wall. Using the example of a flexible polymeric nanoparticle, we illustrate temporal dynamics pertaining to the colloidal scale as well as the nanoscale.

Polymeric Nanoparticles for Brain Drug Delivery - A Review

2020 ◽  
Vol 21 (9) ◽  
pp. 649-660
Author(s):  
Subashini Raman ◽  
Syed Mahmood ◽  
Ayah R. Hilles ◽  
Md Noushad Javed ◽  
Motia Azmana ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Surface Modification ◽  
Polymeric Nanoparticles ◽  
Drug Loading ◽  
Preparation Methods ◽  
Brain Drug Delivery ◽  
Polymeric Nanoparticle ◽  
Relationship Of ◽  
The Relationship ◽  
The Brain

Background: Blood-brain barrier (BBB) plays a most hindering role in drug delivery to the brain. Recent research comes out with the nanoparticles approach, is continuously working towards improving the delivery to the brain. Currently, polymeric nanoparticle is extensively involved in many therapies for spatial and temporal targeted areas delivery. Methods: We did a non-systematic review, and the literature was searched in Google, Science Direct and PubMed. An overview is provided for the formulation of polymeric nanoparticles using different methods, effect of surface modification on the nanoparticle properties with types of polymeric nanoparticles and preparation methods. An account of different nanomedicine employed with therapeutic agent to cross the BBB alone with biodistribution of the drugs. Results: We found that various types of polymeric nanoparticle systems are available and they prosper in delivering the therapeutic amount of the drug to the targeted area. The effect of physicochemical properties on nanoformulation includes change in their size, shape, elasticity, surface charge and hydrophobicity. Surface modification of polymers or nanocarriers is also vital in the formulation of nanoparticles to enhance targeting efficiency to the brain. Conclusion: More standardized methods for the preparation of nanoparticles and to assess the relationship of surface modification on drug delivery. While the preparation and its output like drug loading, particle size, and charge, permeation is always conflicted, so it requires more attention for the acceptance of nanoparticles for brain delivery.

scholarly journals Lipid polymeric nanoparticles modified with tight junction-modulating peptides promote afatinib delivery across a blood–brain barrier model

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yu-Li Lo ◽  
Hua-Ching Lin ◽  
Shu-Ting Hong ◽  
Chih-Hsien Chang ◽  
Chen-Shen Wang ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Tight Junction ◽  
Blood Brain Barrier ◽  
Polymeric Nanoparticles ◽  
Growth Factor Receptor ◽  
Brain Barrier ◽  
Polymeric Nanoparticle ◽  
Blood Brain ◽  
Blood Brain Barrier Model ◽  
Delivery Platform

Abstract Background Brain metastases from non-small cell lung cancer (NSCLC) remain one of the most challenging malignancies. Afatinib (Afa) is an orally administered irreversible ErbB family blocker approved for epidermal growth factor receptor (EGFR)-mutated NSCLC. However, the incidence of brain metastases in patients with NSCLC and EGFR mutation is high. One of the major obstacles in the treatment of brain metastases is to transport drugs across the blood–brain barrier (BBB). A lipid polymeric nanoparticle (LPN) modified with a tight junction-modulating peptide is a potential formulation to deliver therapeutics across the BBB. FD7 and CCD are short peptides that perturb the tight junctions (TJs) of the BBB. In this study, the use of LPN modified with FD7 or CCD as a delivery platform was explored to enhance Afa delivery across the BBB model of mouse brain-derived endothelial bEnd.3 cells. Results Our findings revealed that Afa/LPN-FD7 and Afa/LPN-CCD exhibited a homogeneous shape, a uniform nano-scaled particle size, and a sustained-release profile. FD7, CCD, Afa/LPN-FD7, and Afa/LPN-CCD did not cause a significant cytotoxic effect on bEnd.3 cells. Afa/LPN-FD7 and Afa/LPN-CCD across the bEnd.3 cells enhanced the cytotoxicity of Afa on human lung adenocarcinoma PC9 cells. FD7 and CCD-modulated TJ proteins, such as claudin 5 and ZO-1, reduced transendothelial electrical resistance, and increased the permeability of paracellular markers across the bEnd.3 cells. Afa/LPN-FD7 and Afa/LPN-CCD were also partially transported through clathrin- and caveolae-mediated transcytosis, revealing the effective activation of paracellular and transcellular pathways to facilitate Afa delivery across the BBB and cytotoxicity of Afa on PC9 cells. Conclusion TJ-modulating peptide-modified LPN could be a prospective platform for the delivery of chemotherapeutics across the BBB to the brain for the potential treatment of the BM of NSCLC.

Possible Mechanisms for Thermal Conductivity Enhancement in Nanofluids

2006 ◽  
Author(s):  
Amit Gupta ◽  
Xuan Wu ◽  
Ranganathan Kumar
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Brownian Motion ◽  
Brownian Dynamics ◽  
Lattice Vibration ◽  
Experimental Studies ◽  
High Heat ◽  
Conductivity Enhancement ◽  
High Heat Transfer ◽  
Dynamics Simulations

This study discusses the merits of various physical mechanisms that are responsible for enhancing the heat transfer in nanofluids. Experimental studies have cemented the claim that ‘seeding’ liquids with nanoparticles can increase the thermal conductivity of the nanofluid by up to 40% for metallic and oxide nanoparticles dispersed in a base liquid. Experiments have also shown that the rise in conductivity of the nanofluid is highly dependent on the size and concentration of the nanoparticles. On the theoretical side, traditional models like Maxwell or Hamilton-Crosser models cannot explain this unusually high heat transfer. Several mechanisms have been postulated in the literature such as Brownian motion, thermal diffusion in nanoparticles and thermal interaction of nanoparticles with the surrounding fluid, the formation of an ordered liquid layer on the surface of the nanoparticle and microconvection. This study concentrates on 3 possible mechanisms: Brownian dynamics, microconvection and lattice vibration of nanoparticles in the fluid. By considering two nanofluids, copper particles dispersed in ethylene glycol, and silica in water, it is determined that translational Brownian motion of the nanoparticles, presence of an interparticle potential and the microconvection heat transfer are mechanisms that play only a smaller role in the enhancement of thermal conductivity. On the other hand, the lattice vibrations, determined by molecular dynamics simulations show a great deal of promise in increasing the thermal conductivity by as much as 23%. In a simplistic sense, the lattice vibration can be regarded as a means to simulate the phononic transport from solid to liquid at the interface.

Observation of Brownian motion on the time scale of hydrodynamic interactions

1993 ◽  
Vol 70 (2) ◽  
pp. 242-245 ◽  
Author(s):  
M. H. Kao ◽  
A. G. Yodh ◽  
D. J. Pine
Keyword(s):  
Brownian Motion ◽  
Time Scale ◽  
Hydrodynamic Interactions
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