280 research outputs found
First Principles Derivation of Effective Ginzburg-Landau Free Energy models for Crystalline Systems
The expression of the free energy density of a classical crystalline system
as a gradient expansion in terms of a set of order parameters is developed
using classical density functional theory. The goal here is to extend and
complete an earlier derivation by L{\"o}wen et al (Europhys. Lett.9, 791,
1989). The limitations of the resulting expressions are also discussed
including the boundary conditions needed for finite systems and the fact that
the results cannot, at present, be used to take into account elastic
relaxation.Comment: 12 pages, no figures, sumitted to Physica
U-251MG Spheroid Generation Using Hanging Drop Method Protocol
The use of 3D cell culture has been a major step in developing cellular models that can mimic physiological tissues. Traditional 2D cell cultures are often unable to accurately represent the cellular functions and responses that are present in tissues, as a result, research findings based on 2D cultures tend to be skewed with limited predictive capability. 3D cell cultures can be grown from cells obtained from cancer organoids in patients. These models are useful for understanding disease mechanisms and exploring drug therapeutics in areas such as toxicity and efficacy. In order to gather more physiologically relevant data, a variety of 3D cell culture techniques have been developed to mimic the in vivo characteristics of physiological tissues. This protocol describes in vitro generation of U-251MG spheroids using the hanging drop method. Advantages of using hanging drop plate method are, able to produce uniform size spheroids, low cost, comfortable to handling and suitable for short term culture. The main downside of this method is medium change, different drug treatment at different time points are impossible and labor intensive. This method uses the Perfecta3D hanging drop plate, a novel cell culture device that simplifies the process of spheroid formation, testing and analysis. Rather than having to invert the plates which often results in spillage or detachment, these plates are designed to create hanging drops using a plateau structure at the bottom of the plate
U-251MG Spheroid generation using a scaffold based method protocol
3D cell culture is a technique that is used to grow cells in vitro that will mimic an in vivo environment. 3D cell models are a helpful learning tool for researchers to better understand disease mechanisms and to explore different therapeutic properties of drugs. 3D cell cultures can be developed using patient derived cancer cells. Once they have been grown, these 3D cells can be used to screen for small molecule drugs or for genetic modification in for analysis of disease pathways or to predict drug treatments toxicity or efficacy. 3D cell cultures are a big step towards the more ethical testing of drug toxicity and efficacy as they decrease the need to use animals in research as well as providing more reliable results as the cells used are of human physiology. Cellusponge are 3D porous hydroxipropylcellulose scaffolds that are designed for use with cells that do not require specific ligands. As well as the standard non-coated cellusponge, there are two more of the same type of scaffold available for use that are made with two different coatings to allow for improved adaptation of different cell types, these are called Cellusponge-Gal and Cellusponge-Col. Cellusponge is a no-coating approach that is intended for use in the development of general soft tissue 3D culture. It has been used as soft matrix for 3D cell culture and 3D tumour model
U-251MG Spheroid generation using low attachment plate method protocol
3D cell culture is a process used to grow cells in vitro to mimic an in vivo environment. 3D cell models are very useful for understanding disease mechanisms and exploring drug therapeutics. 3D cultures can be grown from cells taken from cancer organoids in patients. Once grown, they can be used to screen for small molecule drugs or they can be genetically modified in order to analyse disease pathways or predict the toxicity or efficacy of a drug treatment. These cultures decrease the need to use animals in research and provides more reliable results as it uses human physiology. This protocol describes the in vitro generation of spheroids using the low attachment plate method. This method uses low-adhesion plates that are coated with hydrophilic polymer to allow cells to cluster together, forming their own extracellular matrix, rather than sticking to the plate surface. The scaffold-free 3D cell culture models produced can more accurately reflect an in vivo microenvironment making them useful in the study of oncology, hepatotoxicity, neurology, nephrology and stem cell biology
Plasma induced reactive oxygen species-dependent cytotoxicity in glioblastoma 3D tumourspheres
The aim of this study was to determine the effects of a pin‐to‐plate cold atmospheric plasma (CAP) on U‐251 MG three‐dimensional (3D) glioblastoma spheroids under different conditions. 3D tumorspheres showed higher resistance to the CAP treatment compared to 2D monolayer cells. A single CAP treatment was able to induce cytotoxicity, while multiple CAP treatments augmented this effect. CAP was also able to induce cytotoxicity throughout the tumoursphere, and we identified that reactive oxygen species(ROS) plays a major role, while H2O2plays a partial role in CAP‐induced cytotoxicity in tumour-spheres. We conclude that ROS‐dependent cytotoxicity is induced uniformly throughout glioblastoma and epidermoid tumourspheres by direct CAP treatment
Advances in 3D culture systems for therapeutic discovery and development in brain cancer
This review focuses on recent advances in 3D culture systems that promise more accurate therapeutic models of the glioblastoma multiforme (GBM) tumor microenvironment (TME), such as the unique anatomical, cellular, and molecular features evident in human GBM. The key components of a GBM TME are outlined, including microbiomes, vasculature, extracellular matrix (ECM), infiltrating parenchymal and peripheral immune cells and molecules, and chemical gradients. 3D culture systems are evaluated against 2D culture systems and in vivo animal models. The main 3D culture techniques available are compared, with an emphasis on identifying key gaps in knowledge for the development of suitable platforms to accurately model the intricate components of the GBM TME
A Novel, Rapid, Seedless, in Situ Synthesis Method of Shape and Size Controllable Gold Nanoparticles using Phosphates
We hereby report a novel synthesis method of size and shape controllable gold nanoparticles that is rapid, in situ and seedless. Unlike most currently employed size and shape controllable synthesis methods, it takes place in a single step under room temperature within ~15 minutes. While mixtures of gold nanospheres around 70 nm and gold nanoplates with width ranging from 100 nm to 1000 nm can be synthesized in about 15 minutes by standard synthesis method using N-2-hydroxyethylpiperazine-N-2-ethanesulphonic acid (HEPES) to reduce Au(III), gold nanoflowers or mixtures of smaller gold nanospheres and nanoplates can be synthesized with the addition of disodium phosphate (Na2HPO4) or monosodium phosphate (NaH2PO4), respectively. Increasing the concentration of phosphate added significantly reduces the formation time of gold nanoparticles to seconds. By increasing the molar ratio of Na2HPO4 : HEPES and NaH2PO4 : HEPES, the size of gold nanoflowers and gold nanoparticle mixtures can be tuned from ~60 nm down to 1 nm and from ~70 nm to ~2.5 nm, respectively. The systematic structural changes are accompanied by similarly systematic colour changes associated with shifting of the surface plasmon resonance. The proposed mechanism of the synthesis process is also presented
Ultrasound 96 Probe Device Protocol for cancer cell treatment
Ultrasound is a sound wave with frequencies ranging between 20 kHz and 20 MHz. Ultrasound is able to temporarily and repeatedly open the BBB safely and enhance chemotherapeutic delivery without adverse effects. This novel technique in drug delivery benefits from the powerful ability of ultrasound to produce cavitation activity. Cavitation is the generation and activity of gas-filled bubbles in a medium exposed to ultrasound. As the pressure wave passes through the media, gas bubbles expand at low pressure and contract at high pressure. This leads to oscillation which produces a circulating fluid flow known as microstreaming around the bubble with velocities and shear rates proportional to the amplitude of the oscillation. At high amplitudes the associated shear forces can cut open liposome
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