scholarly journals Passive Control of Silane Diffusion for Gradient Application of Surface Properties

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1360
Author(s):  
Riley L. Howard ◽  
Francesca Bernardi ◽  
Matthew Leff ◽  
Emma Abele ◽  
Nancy L. Allbritton ◽  
...  
Keyword(s):  
Passive Control ◽  
Three Dimensional ◽  
Diffusion Chamber ◽  
Passive Diffusion ◽  
Two Dimensional ◽  
Single Chip ◽  
Lithography Process ◽  
Single Opening ◽  
Passive Technique

Liquid lithography represents a robust technique for fabricating three-dimensional (3D) microstructures on a two-dimensional template. Silanization of a surface is often a key step in the liquid lithography process and is used to alter the surface energy of the substrate and, consequently, the shape of the 3D microfeatures produced. In this work, we present a passive technique that allows for the generation of silane gradients along the length of a substrate. The technique relies on a secondary diffusion chamber with a single opening, leading to a directional introduction of silane to the substrate via passive diffusion. The secondary chamber geometry influences the deposited gradient, which is shown to be well captured by Monte Carlo simulations that incorporate the passive diffusion and grafting processes. The technique ultimately allows the user to generate a range of substrate wettabilities on a single chip, enhancing throughput for organ-on-a-chip applications by mimicking the spatial variability of tissue topographies present in vivo.

scholarly journals Recapitulating tumour microenvironment in chitosan–gelatin three-dimensional scaffolds: an improved in vitro tumour model

2012 ◽  
Vol 9 (77) ◽  
pp. 3288-3302 ◽  
Author(s):  
Neha Arya ◽  
Viren Sardana ◽  
Meera Saxena ◽  
Annapoorni Rangarajan ◽  
Dhirendra S. Katti
Keyword(s):  
Cancer Progression ◽  
Expression Profiles ◽  
Three Dimensional ◽  
Gene Expression Profiles ◽  
Petri Dish ◽  
Tumour Microenvironment ◽  
Two Dimensional ◽  
Tumour Model

Owing to the reduced co-relationship between conventional flat Petri dish culture (two-dimensional) and the tumour microenvironment, there has been a shift towards three-dimensional culture systems that show an improved analogy to the same. In this work, an extracellular matrix (ECM)-mimicking three-dimensional scaffold based on chitosan and gelatin was fabricated and explored for its potential as a tumour model for lung cancer. It was demonstrated that the chitosan–gelatin (CG) scaffolds supported the formation of tumoroids that were similar to tumours grown in vivo for factors involved in tumour-cell–ECM interaction, invasion and metastasis, and response to anti-cancer drugs. On the other hand, the two-dimensional Petri dish surfaces did not demonstrate gene-expression profiles similar to tumours grown in vivo . Further, the three-dimensional CG scaffolds supported the formation of tumoroids, using other types of cancer cells such as breast, cervix and bone, indicating a possible wider potential for in vitro tumoroid generation. Overall, the results demonstrated that CG scaffolds can be an improved in vitro tool to study cancer progression and drug screening for solid tumours.

scholarly journals Motility of spermatozoa at surfaces

Reproduction ◽  
2003 ◽  
pp. 259-270 ◽  
Author(s):  
DM Woolley
Keyword(s):  
Three Dimensional ◽  
Neck Region ◽  
Sperm Head ◽  
Solid Boundary ◽  
Cylindrical Shape ◽  
Two Dimensional ◽  
Flagellar Beat ◽  
Planar Shape ◽  
Planar Wave

The hydrodynamic basis for the accumulation of spermatozoa at surfaces has been investigated. The general conclusion is that when spermatozoa arrive at a surface, they will remain there if the vector of the time-averaged thrust is directed towards that surface. This can arise in two basic ways. First, consider spermatozoa that maintain a three-dimensional waveform and roll (spin) as they progress: in this case, it is argued that the conical (rather than cylindrical) shape of the flagellar envelope will establish the direction-of-thrust necessary for capture by the surface. (Additional findings, for spermatozoa of this type, are that the swim-trajectory is curved and that the direction of its curvature reveals the roll-direction of the cell.) Second, consider spermatozoa that maintain a strictly two-dimensional waveform at the surface: in this case, spermatozoa can be captured because the plane-of-flattening of the sperm head is tilted slightly relative to the plane of the flagellar beat. The sperm head is acting as a hydrofoil and, in one orientation only, it comes to exert a pressure against the surface. (This pressure may possibly, in vivo, aid the penetration of the zona pellucida.) The hydrofoil action of sperm heads may explain any bias in the circling direction of spermatozoa that execute two-dimensional waves at surfaces. Finally, a more complex phenomenon is where interaction of the spermatozoa with the surface appears to induce a three-dimensional to two-dimensional conversion of the flagellar wave (thus permitting the hydrofoil effect described). This is characteristic of sperm with 'twisted planar' rather than helical waves. In mammalian spermatozoa, approximately half the beat cycle is planar and the other half generates a pattern of torque causing the head to roll clockwise (seen from ahead), producing a torsion of the neck region of the flagellum. It is the gradual suppression of this torsion, by either impedance at the solid boundary or by raised viscosity, that converts the 'twisted planar' shape into a planar wave.

Rapid Three-Dimensional Segmentation of the Carotid Bifurcation From Serial MR Images

1999 ◽  
Vol 122 (1) ◽  
pp. 96-99 ◽  
Author(s):  
H. M. Ladak ◽  
J. S. Milner and ◽  
D. A. Steinman
Keyword(s):  
Ex Vivo ◽  
Current Trend ◽  
Three Dimensional ◽  
Carotid Bifurcation ◽  
Cfd Modeling ◽  
Black Blood ◽  
Two Dimensional ◽  
Surface Geometry ◽  
Three Dimensional Segmentation

The current trend in computational hemodynamics is to employ realistic models derived from ex vivo or in vivo imaging. Such studies typically produce a series of images from which the lumen boundaries must first be individually extracted (i.e., two-dimensional segmentation), and then serially reconstructed to produce the three-dimensional lumen surface geometry. In this paper, we present a rapid three-dimensional segmentation technique that combines these two steps, based on the idea of an expanding virtual balloon. This three-dimensional technique is demonstrated in application to finite element meshing and CFD modeling of flow in the carotid bifurcation of a normal volunteer imaged with black blood MRI. Wall shear stress patterns computed using a mesh generated with the three-dimensional technique agree well with those computed using a mesh generated from conventional two-dimensional segmentation and serial reconstruction. In addition to reducing the time required to extract the lumen surface from hours to minutes, our approach is easy to learn and use and requires minimal user intervention, which can potentially increase the accuracy and precision of quantitative and longitudinal studies of hemodynamics and vascular disease. [S0148-0731(00)00201-6]

Linear Polyp Measurement at CT Colonography: In Vitro and in Vivo Comparison of Two-dimensional and Three-dimensional Displays

Radiology ◽  
2005 ◽  
Vol 236 (3) ◽  
pp. 872-878 ◽  
Author(s):  
Perry J. Pickhardt ◽  
Andrew D. Lee ◽  
Elizabeth G. McFarland ◽  
Andrew J. Taylor
Keyword(s):  
Ct Colonography ◽  
Three Dimensional ◽  
Two Dimensional

scholarly journals Ex Vivo MR Histology and Cytometric Feature Mapping Connect Three-dimensional in Vivo MR Images to Two-dimensional Histopathologic Images of Murine Sarcomas

2021 ◽  
Vol 3 (3) ◽  
pp. e200103
Author(s):  
Stephanie J. Blocker ◽  
James Cook ◽  
Yvonne M. Mowery ◽  
Jeffrey I. Everitt ◽  
Yi Qi ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Mr Images ◽  
Feature Mapping

In Vitro Follicle Growth, Maturation, and Gene Expression: Three-Dimensional (3D) Matrigel Culture versus Two-Dimensional Culture (2D)

2021 ◽  
Vol 11 (12) ◽  
pp. 2512-2515
Author(s):  
Byoung-San Moon ◽  
Seungki Lee ◽  
Jung Kyu Choi
Keyword(s):  
Gene Expression ◽  
Three Dimensional ◽  
Ovarian Follicles ◽  
Dimensional System ◽  
Two Dimensional ◽  
Follicle Growth ◽  
Adult Mice ◽  
Three Dimensional Culture

This research aimed to compare the In Vitro growth, maturation, and gene expression in ovarian follicles collected from adult mice (6–8-week-old) between two-dimensional and three-dimensional cultures. First, we confirmed In Vitro follicle growth and maturation using adult mice with outbred characteristics and analyzed the expression of genes related to follicular development. We found that the three-dimensional culture system utilizing a Matrigel drop to create an in vivo-like ovarian microenvironment was more efficient in terms of In Vitro follicle growth, maturation, and gene expression than the two-dimensional system (non-physical environment). The in vivo-like three-dimensional culture of ovarian follicles provides new insights into the physiology and development of ovarian follicle in vivo, thereby contributing to new strategies to improve female fertility.

scholarly journals Bi-functional oxidized dextran–based hydrogel inducing microtumors: An in vitro three-dimensional lung tumor model for drug toxicity assays

2017 ◽  
Vol 8 ◽  
pp. 204173141771839 ◽  
Author(s):  
Dhaval Kedaria ◽  
Rajesh Vasita
Keyword(s):  
Drug Screening ◽  
Drug Toxicity ◽  
Disease Modeling ◽  
Lung Tumor ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Chitosan Hydrogel ◽  
Oxidized Dextran

Cancer is a serious death causing disease having 8.2 million deaths in 2012. In the last decade, only about 10% of chemotherapeutic compounds showed productivity in drug screening. Two-dimensional culture assays are the most common in vitro drug screening models, which do not precisely model the in vivo condition for reliable preclinical drug screening. Three-dimensional scaffold–based cell cultures perhaps mimic tumor microenvironment and recapitulate physiologically more relevant tumor. This study was carried out to develop bi-functional oxidized dextran–based cell instructive hydrogel that provides three-dimensional environment to cancer cells for inducing microtumor. Oxidized dextran was blended with thiolated chitosan to fabricate an in situ self-gelable hydrogel (modified dextran–chitosan) in a one-step process. The hydrogels characterization revealed cross-linked network structure with highly porous structure and water absorption. The modified dextran–chitosan hydrogel showed reduced hydrophobicity and has reduced protein absorption, which resulted in changing the A549 cell adhesiveness, and encouraged them to form microtumor. The cells were proliferated in clusters having spherical morphology with randomly oriented stress fiber and large nucleus. Further microtumors were studied for hypoxia where reactive oxygen species generation demonstrated 15-fold increase as compared to monolayer culture. Drug-sensitivity results showed that microtumors generated on modified dextran–chitosan hydrogel showed resistance to doxorubicin with having 33%–58% increased growth than two-dimensional monolayer model at concentrations of 25–100 µM. In summary, the modified dextran–chitosan scaffold can provide surface chemistry that induces three-dimensional microtumors with physiologically relevant properties to in vivo tumor including growth, morphology, extracellular matrix production, hypoxic phenotype, and drug response. This model can be potentially utilized for drug toxicity studies and cancer disease modeling to understand tumor phenotype and progression.

scholarly journals Comparison of drug inhibitory effects (IC50) in monolayer and spheroid cultures

2020 ◽  
Author(s):  
Catherine Berrouet ◽  
Naika Dorilas ◽  
Katarzyna A. Rejniak ◽  
Necibe Tuncer
Keyword(s):  
Three Dimensional ◽  
Drug Dosage ◽  
Drug Action ◽  
Computational Studies ◽  
Two Dimensional ◽  
Inhibitory Effects ◽  
Action Mechanisms ◽  
Low Concentrations ◽  
Dimensional Cell

AbstractTraditionally, the monolayer (two-dimensional) cell cultures are used for initial evaluation of the ef-fectiveness of anticancer drugs. In particular, these experiments provide the IC50 curves that determine drug concentration that can inhibit growth of a tumor colony by half when compared to the cells grown with no exposure to the drug. Low IC50 value means that the drug is effective at low concentrations, and thus will show lower systemic toxicity when administered to the patient. However, in these experiments cells are grown in a monolayer, all well exposed to the drug, while in vivo tumors expand as three-dimensional multicellular masses, where inner cells have a limited access to the drug. Therefore, we performed computational studies to compare the IC50 curves for cells grown as a two-dimensional monolayer and a cross section through a three-dimensional spheroid. Our results identified conditions (drug diffusivity, drug action mechanisms and cell proliferation capabilities) under which these IC50 curves differ significantly. This will help experimentalists to better determine drug dosage for future in vivo experiments and clinical trials.

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