Nanoparticle core properties affect attachment of macromolecule-coated nanoparticles to silica surfaces

2014 ◽  
Vol 11 (3) ◽  
pp. 257 ◽  
Author(s):  
Ernest M. Hotze ◽  
Stacey M. Louie ◽  
Shihong Lin ◽  
Mark R. Wiesner ◽  
Gregory V. Lowry
Keyword(s):  
Particle Size ◽  
Layer Thickness ◽  
Adsorbed Layer ◽  
Engineered Nanoparticles ◽  
Soft Particle ◽  
Nanoparticle Transport ◽  
Silica Surfaces ◽  
Coated Particle ◽  
Coated Nanoparticles ◽  
Coating Type

Environmental context The increasing use of engineered nanoparticles has led to concerns over potential exposure to these novel materials. Predictions of nanoparticle transport in the environment and exposure risks could be simplified if all nanoparticles showed similar deposition behaviour when coated with macromolecules used in production or encountered in the environment. We show, however, that each nanoparticle in this study exhibited distinct deposition behaviour even when coated, and hence risk assessments may need to be specifically tailored to each type of nanoparticle. Abstract Transport, toxicity, and therefore risks of engineered nanoparticles (ENPs) are unquestionably tied to interactions between those particles and surfaces. In this study, we proposed the simple and untested hypothesis that coating type can be the predominant factor affecting attachment of ENPs to silica surfaces across a range of ENP and coating types, effectively masking the contribution of the particle core to deposition behaviour. To test this hypothesis, TiO2, Ag0 and C60 nanoparticles with either no coating or one of three types of adsorbed macromolecules (poly(acrylic acid), humic acid and bovine serum albumin) were prepared. The particle size and adsorbed layer thicknesses were characterised using dynamic light scattering and soft particle electrokinetic modelling. The attachment efficiencies of the nanoparticles to silica surfaces (glass beads) were measured in column experiments and compared with predictions from a semi-empirical correlation between attachment efficiency and coated particle properties that included particle size and layer thickness. For the nanoparticles and adsorbed macromolecules in this study, the attachment efficiencies could not be explained solely by the coating type. Therefore, the hypothesis that adsorbed macromolecules will mask the particle core and control attachment was disproved, and information on the properties of both the nanoparticle surface (e.g. charge and hydrophobicity) and adsorbed macromolecule (e.g. molecular weight, charge density extended layer thickness) will be required to explain or predict interactions of coated nanoparticles with surfaces in the environment.

A SIMULATION STUDY ON THE EFFECT OF PARTICLE SIZE DISTRIBUTION ON THE PRINTED GEOMETRY IN SELECTIVE LASER MELTING

2021 ◽  
pp. 1-14
Author(s):  
Vaishak Ramesh Sagar ◽  
Samuel Lorin ◽  
Johan Göhl ◽  
Johannes Quist ◽  
Christoffer Cromvik ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Layer Thickness ◽  
Selective Laser Melting ◽  
Laser Melting ◽  
Powder Bed ◽  
Mean Particle Size ◽  
Final Layer ◽  
Effect Of Particle Size

Abstract Selective laser melting (SLM) process is a powder bed fusion additive manufacturing process that finds applications in aerospace and medical industries for its ability to produce complex geometry parts. As the raw material used is in powder form, particle size distribution (PSD) is a significant characteristic that influences the build quality in turn affecting the functionality and aesthetics aspects of the product. This paper investigates the effect of PSD on the printed geometry for 316L stainless steel powder, where three coupled in-house simulation tools based on Discrete Element Method (DEM), Computational Fluid Dynamics (CFD), and Structural Mechanics are employed. DEM is used for simulating the powder bed distribution based on the different powder PSD. The CFD is used as a virtual testbed to determine thermal parameters such as heat capacity and thermal conductivity of the powder bed viewed as a continuum. The values found as a stochastic function of the powder distribution is used to analyse the effect on the melted zone and deformation using Structural Mechanics. Results showed that mean particle size and PSD had a significant effect on the packing density, melt pool layer thickness, and the final layer thickness after deformation. Specifically, a narrow particle size distribution with smaller mean particle size and standard deviation produced solidified final layer thickness closest to nominal layer thickness. The proposed simulation approach and the results will catalyze in development of geometry assurance strategies to minimize the effect of particle size distribution on the geometric quality of the printed part.

scholarly journals Particle diffusional layer thickness in a USP dissolution apparatus II: A combined function of particle size and paddle speed

2008 ◽  
Vol 97 (11) ◽  
pp. 4815-4829 ◽  
Author(s):  
Jennifer J. Sheng ◽  
Paul J. Sirois ◽  
Jennifer B. Dressman ◽  
Gordon L. Amidon
Keyword(s):  
Particle Size ◽  
Layer Thickness ◽  
Dissolution Apparatus

scholarly journals DEVELOPMENT OF SODIUM ALGINATE COATED NANOPARTICLES OF METRONIDAZOLE FOR THE TREATMENT OF PERIODONTITIS

2019 ◽  
pp. 105-110 ◽  
Author(s):  
MUKUL SINGH ◽  
GAURAV JAIN
Keyword(s):  
Particle Size ◽  
Sodium Alginate ◽  
Biological Membrane ◽  
Spherical Shape ◽  
Prolonged Treatment ◽  
Prolonged Action ◽  
Sem Images ◽  
Mean Particle Size ◽  
Coated Nanoparticles ◽  
Acceptable Range

Objective: The present study was aimed to develop metronidazole (MNZ) loaded poly lactic-co-glycolic acid (PLGA) based mucoadhesive nanoparticles (NPs) in prolonged treatment in periodontitis. Methods: Nanoparticles were prepared by using single (SE) and double (DE) emulsion method to determine the suitability of methods. Prepared NPs were evaluated for surface morpholgy, mean particle size, polydispersity index, zeta potential, mucoadhesion ability and invitro-drug release, Results: SEM images confirmed that NPs were of spherical shape and smooth surface. Mean particle size, of MNZ loaded NPs were found 583.28±18.22 and 872.72±63.18 prepared by SE and DE method. Similarly, polidispersity index (0.68±0.1 and 0.83±0.06) and zeta potention (-33.29±0.7 and-31.28.0.6) was found in acceptable range. Prepared NPs were surface treated with Sodium alginate (SA) to increase mucoadhesive property. It was observe that particles remain adhere till 24 hr with biological membrane. Prepared NPs allow release of MNZ upto 24 h in sustained manner. Conclusion: This study confirms that the prepared MNZ loaded NPs may be used as an better alternate with addition application such as prolonged action thus improved patient compliance.

scholarly journals Ocular pharmacoscintigraphic and aqueous humoral drug availability of ganciclovir-loaded mucoadhesive nanoparticles in rabbits

2013 ◽  
Vol 5 (3) ◽  
Author(s):  
Sohail Akhter ◽  
Farshad Ramazani ◽  
Mohammad Zaki Ahmad ◽  
Farhan Jalees Ahmad ◽  
Ziyaur Rahman ◽  
...  
Keyword(s):  
Particle Size ◽  
Aqueous Humor ◽  
Residence Time ◽  
Present Report ◽  
Plga Nanoparticles ◽  
Drug Availability ◽  
Rabbit Eye ◽  
Chitosan Coating ◽  
Coated Nanoparticles ◽  
Ocular Retention

AbstractThe present report describes the improved ocular retention and aqueous humoral drug availability of ganciclovir (GCV) when administered via topical instillation of different kind of nanoparticles onto the rabbit eye. GCV was loaded into PLGA nanoparticles, chitosan-coated nanoparticles and chitosan-coated niosomal nanoparticles. All three formulations contained nanoparticles equally round in shape with a mean particle size in the range of 180–200 nm. The ocular corneal retention property was evaluated by gamma scintigraphy, revealing that the clearance was slowest in the case of the chitosan-containing formulations. GCV in chitosan-coated PLGA nanoparticles and chitosan-coated niosomal nanoparticles showed approx. 6-fold higher aqueous humor drug availability as compared to a GCV solution and nearly 2.5-fold higher as compared to the chitosan-lacking GCV-PLGA nanoparticles. The results indicate that the use of a mucoadhesive chitosan coating can improve the ocular residence time and aqueous humoral availability of GCV when administered topically in nanoparticles.

Composite nanosilver structures suitable for plasmonic biosensors

2012 ◽  
Vol 1416 ◽  
Author(s):  
Georgios A. Sotiriou ◽  
Christoph O. Blattmann ◽  
Sotiris E. Pratsinis
Keyword(s):  
Particle Size ◽  
Amorphous Silica ◽  
Plasmon Resonance ◽  
Ag Nanoparticles ◽  
Flame Spray Pyrolysis ◽  
Flame Spray ◽  
The Core ◽  
Coated Nanoparticles ◽  
Ag Particle ◽  
Plasmon Resonance Frequency

ABSTRACTSilver (Ag) nanoparticles dispersed in an amorphous silica (SiO2) matrix or coated by a SiO2 layer were synthesized by flame spray pyrolysis (FSP). The coated nanoparticles were produced by using a modified enclosed FSP setup, in which the SiO2 precursor was injected through a ring above the FSP nozzle at various burner-ring-distances (BRDs), after the core Ag nanoparticles had been formed. The produced nanoparticles were characterized by XRD, BET, TEM and UV/vis analysis. The Ag particle size was possible to be controlled by tuning the FSP parameters. For the SiO2 coated nanoparticles, larger Ag core sizes were obtained for higher BRDs. All the produced nanoparticles exhibited the characteristic plasmon resonance frequency of Ag nanoparticles.

Direct characterization of adsorbed surfactant layers

Surfactants ◽  
2019 ◽  
pp. 156-174
Author(s):  
Bob Aveyard
Keyword(s):  
Refractive Index ◽  
Layer Thickness ◽  
Quartz Crystal Microbalance ◽  
Adsorbed Layer ◽  
Phase Behaviour ◽  
Aqueous Systems ◽  
Brewster Angle Microscopy ◽  
Physical Investigation ◽  
Neutron Reflection

Some widely used techniques for the direct physical investigation of the structure of adsorbed surfactant films are introduced. Neutron reflection has yielded very detailed information about adsorbed surfactant films, although it is not readily accessible to many researchers. There are however commercial instruments available for a number of other techniques which are to be found in numerous laboratories. Scanning probe microscopies (STM and AFM) are capable of producing quite remarkable images of surfactant layers on solids and clearly show how surfactants form aggregates at surfaces. Ellipsometry is capable of yielding adsorbed layer thickness and refractive index from which composition with respect to solvent and surfactant can be deduced. The quartz crystal microbalance (QCM) and its variant, QCM-D, can give adsorbed amounts (including hydration in aqueous systems). Brewster angle microscopy (BAM) is a useful tool for the visualization of phase behaviour in surfactant films.

Glimpse into Cellular Internalization and Intracellular Trafficking of Lipid-Based Nanoparticles in Cancer Cells

2021 ◽  
Vol 21 ◽  
Author(s):  
Elham Kamalkazemi ◽  
Fereydoon Abedi - Gaballu ◽  
Tala Farid Mohammad Hosseini ◽  
Ali Mohammadi ◽  
Behzad Mansoori ◽  
...  
Keyword(s):  
Particle Size ◽  
Cancer Cells ◽  
Cellular Uptake ◽  
Therapeutic Agents ◽  
Cellular Internalization ◽  
Intracellular Accumulation ◽  
Coated Nanoparticles ◽  
Cargo Delivery ◽  
Anti Cancer ◽  
Intracellular Fate

: Lipid-based nanoparticles as drug delivery carriers have been mainly used for delivery of anti-cancer therapeutic agents. Lipid-based nanoparticles, due to their smaller particle size and similarity to cell membranes, are readily internalized into cancer cells. Interestingly, cancer cells also overexpress receptors for specific ligands including folic acid, hyaluronic acid, and transferrin on their surface. This allows the use of these ligands for surface modification of the lipid-based nanoparticle. These modifications then allow the specific recognition of these ligand-coated nanoparticles by their receptors on cancer cells allowing the targeted gradual intracellular accumulation of the functionalized nanoplatforms. These interactions could eventually enhance the internalization of desired drugs via increasing ligand-receptor mediated cellular uptake of the nanoplatforms. The cellular internalization of the nanoplatforms also varies and depends on their physicochemical properties including particle size, zeta potential, and shape. The cellular uptake is also influenced by the types of ligand internalization pathway utilized by cells such as phagocytosis, macropinocytosis, and multiple endocytosis pathways. In this review, we will classify and discuss lipid based nanoparticles engineered to express specific ligands, and are recognized by their receptors on cancer cell, and their cellular internalization pathways. Moreover, the intracellular fate of nanoparticles decorated with specific ligands and the best internalization pathways (caveolae mediated endocytosis) for safe cargo delivery will be discussed.

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