User:Tvanneel/sandbox

Edits from Ashleigh

= Microfluidic cell culture = Microfluidic cell culture integrates knowledge from biology, biochemistry, engineering, and physics  to develop devices and techniques for culturing, maintaining, analyzing, and experimenting with cells at the microscale. It merges microfluidics, a set of technologies used for the manipulation of small fluid volumes (μL, nL, pL) within artificially fabricated microsystems, and  cell culture, which involves the maintenance and growth of cells in a controlled laboratory environment. Microfluidics has been used for cell biology studies as the dimensions of the microfluidic channels are well suited for the physical scale of cells. For example, eukaryotic cells have linear dimensions between 10-100 μm which falls within the range of microfluidic dimensions. A key component of microfluidic cell culture is being able to mimic the cell microenvironment which includes soluble factors that regulate cell structure, function, behavior, and growth. Another important component for the devices is the ability to produce stable gradients that are present in vivo as these gradients play a significant role in understanding chemotactic, durotactic, and haptotactic effects on cells.

Fabrication
Some considerations for microfluidic devices relating to cell culture include: Fabrication material is crucial as not all polymers are biocompatible, with some materials such as PDMS causing undesirable adsorption or absorption of small molecules. Additionally, uncured PDMS oligomers can leach into the cell culture media, which can harm the microenvironment. As an alternative to commonly used PDMS, there have been advances in the use of thermoplastics (e.g., polystyrene) as a replacement material.
 * fabrication material (e.g., polydimethylsiloxane (PDMS), polystyrene)
 * culture region geometry
 * control system for delivering and removing media when needed using either passive methods (e.g., gravity-driven flow, capillary pumps, or Laplace pressure based ‘passive pumping’) or a flow-rate controlled device (i.e., perfusion system)

Spatial organization of cells in microscale devices largely depends on the culture region geometry for cells to perform functions in vivo. For example, long, narrow channels may be desired to culture neurons. The perfusion system chosen might also affect the geometry chosen. For example, in a system that incorporates syringe pumps, channels for perfusion inlet, perfusion outlet, waste, and cell loading would need to be added for the cell culture maintenance. Perfusion in microfluidic cell culture is important to enable long culture periods on-chip and cell differentiation.

Other critical aspects for controlling the microenvironment include: cell seeding density, reduction of air bubbles as they can rupture cell membranes, evaporation of media due to an insufficiently humid environment, and cell culture maintenance (i.e. regular, timely media changes).

Advantages
Some of the major advantages of microfluidic cell culture include reduced sample volumes (especially important when using primary cells, which are often limited) and the flexibility to customize and study multiple microenvironments within the same device. A reduced cell population can also be used in a microscale system (e.g., a few hundred cells) in comparison to macroscale culture systems (which often require 105 – 107 cells); this can make studying certain cell-cell interactions more accessible. These reduced cell numbers make studying non-dividing or slow dividing cells (e.g., stem cells) easier than traditional culture methods (e.g., flasks, petri dishes, or well plates) due to the smaller sample volumes. Given the small dimensions in microfluidics, laminar flow can be achieved, allowing manipulations with the culture system to be done easily without affecting other culture chambers. Laminar flow is also useful as is it mimics in vivo fluid dynamics more accurately, often making microscale culture more relevant than traditional culture methods.

Two-dimensional culture
Two-dimensional (2D) cell culture is cell culture that takes place on a flat surface, e.g. the bottom of a well-plate, and is known as the conventional method. While these platforms are useful for growing and passaging cells to be used in subsequent experiments, they are not ideal environments to monitor cell responses to stimuli as cells cannot freely move or perform functions as observed in vivo that are dependent on cell-extracellular matrix material interactions.

Three-dimensional culture
Three-dimensional (3D) cell culture is cell culture that takes place in a biologically relevant matrix, usually this involves cells being embedded in a hydrogel containing extracellular molecules (e.g., collagen). By adding an additional dimension, more advanced cell architectures can be achieved, and cell behavior is more representative of in vivo dynamics; cells can engage in enhanced communication with neighboring cells and cell-extracellular matrix interactions can be modeled. These simplified 3D cell culture models can be combined in a manner that recapitulates tissue- and organ-level functions in devices known as organ-on-a-chip. In these devices, chambers or collagen layers containing different cell types can interact with one another for multiple days while various channels deliver nutrients to the cells. An advantage of these devices is that tissue function can be characterized and observed under controlled conditions (e.g., effect of shear stress on cells, effect of cyclic strain or other forces) to better understand the overall function of the organ. While these 3D models often better model organ function on a cellular level compared with 2D models, there are still challenges. Some of the challenges include: imaging of the cells, control of gradients in static models (i.e., without a perfusion system), and difficulty recreating vasculature. Despite these challenges, 3D models are still used as tools for studying and testing drug responses in pharmacological studies.

Reflective Essay
I chose to edit the pre-exisiting “Microfluidic cell culture” article. The article was very disjointed, had a lot of incomplete ideas, and lacked references. I added about 4 paragraphs of original text and weaved in the ideas and sentences that other contributors had already written. I also added in citations as there weren’t many on the existing live page. Overall, the article looks more complete but could always use some additions as I didn’t cover everything within microfluidic cell culture. The peer reviewer suggestions were very helpful. I implemented most of the changes as they were grammatical and sentence restructure that improved the article overall. One specific addition was creating a bullet point list under “Fabrication” which made the points I wanted to make easier to read. While I did engage on the talk page, I did not receive feedback from other Wikipedians or consult the Wikipedia content expert. However, I will ask the Wikipedia content expert for more advice on how to add to the live page without offending any of the previous contributors. Overall, I really liked this assignment as it was adding information to the world that hopefully people will use as a good crash course or starting point to microfluidic cell culture.

This assignment was valuable as it made me really research and understand multiple topics and how they work together to advance cell culture platforms. It was fun learning about other research techniques and methods and how they are used in other applications. I got practice in evaluating the validity of papers, their usefulness (or sometimes their irrelevancy), and how to read papers more efficiently. It was helpful having deadlines so I didn’t procrastinate on actually writing and researching for my article. I would have liked having an additional peer review after the final deadline just so any mistakes that were missed could be changed before going live on Wikipedia. My article can use improvement on the fabrication techniques (like photolithography, soft lithography, etc.) as I didn’t talk much, if at all about those techniques. Also, adding how these materials need to be modified to be compatible for cell culture use. I have an “Advantages” heading but lack a “Disadvantages” heading which could be added to ensure there is no bias in the article. Some disadvantages are written in some paragraphs but consolidating into one might also be nice. Additionally, the perfusion system and culture region geometry/fabrication could also be expanded upon.

Final Article
= Microfluidic cell culture = Microfluidic cell culture requires knowledge from biology, biochemistry, engineering, and physics as it attempts to develop devices and techniques for culturing, maintaining, analyzing, and experimenting in cells at the microscale. It merges microfluidics, a set of technologies used for the manipulation of small fluid volumes (μL, nL, pL) within artificially fabricated microsystems, and  cell culture, which involves  the maintenance and growth of cells in a controlled laboratory environment. Microfluidics has predominantly been used for cell biology studies as the dimensions of the microfluidic channels are well suited for the physical scale of cells. For example, eukaryotic cells have linear dimensions between 10-100 μm which falls within the range of microfluidic dimensions. A key component to microfluidic cell culture is being able to mimic the cell microenvironment which includes soluble factors that regulate cell structure, function, behavior, and growth. Another important component for the devices is the ability to produce stable gradients that are present in vivo as these gradients play a significant role in understanding chemotactic, durotactic, and haptotactic effects on cells.

Fabrication
Some considerations for microfluidic devices relating to cell culture include: Fabrication material is crucial as not all polymers are biocompatible, with some causing undesirable adsorption or absorption of small molecules. Additionally, uncured PDMS oligomers can leach into the cell culture media, which can harm the microenvironment.5 As an alternative to the commonly used PDMS, which can be harmful for the aforementioned reasons, there have been advances in the use of thermoplastics (e.g. polystyrene) as a replacement material.
 * fabrication material (e.g. PDMS, polystyrene)
 * culture region geometry
 * control system for delivering and removing media when needed using either passive pumping or a flow-rate controlled device (i.e. perfusion system)

Spatial organization of cells on the microscale largely depends on the culture region geometry for cells to perform functions in vivo. For example, long, narrow channels may be desired to culture neurons. The perfusion system chosen might also affect the geometry chosen. For example, in a system that incorporates syringe pumps, channels for perfusion inlet, perfusion outlet, waste, and cell loading would need to be added for the cell culture maintenance. Perfusion in microfluidic cell culture is important to enable long culture periods on-chip and cell differentiation.

Other critical aspects for controlling the microenvironment include: cell seeding density, reduction of air bubbles as they can rupture cell membranes, evaporation of media due to an insufficiently humid environment, and cell culture maintenance (i.e. regular, timely media changes).

Advantages
Some of the major advantages to microfluidic cell culture are reduced sample volumes (especially important when using primary cells) and the flexibility to customize and study multiple microenvironments within the same device. Given the small dimensions in microfluidics, laminar flow can be achieved, allowing manipulations with the culture system to be done easily without affecting other culture chambers. Laminar flow is also useful as is it mimics in vivo fluid dynamics more accurately, making it more relevant than traditional culture methods. A reduced cell population can also be used in a microscale system, few hundred cells versus 105 – 107 cells in a macroscopic system, which can make studying certain cell-cell interactions more accessible. These reduced cell numbers make studying non-dividing or slow dividing cells (e.g. stem cells) easier than traditional culture methods (e.g. flasks, petri dishes, or well plates) due to the smaller sample volumes.

Two-dimensional culture
Cell culture that takes place on a flat surface, e.g. the bottom of a well-plate, is the conventional method for most and is known as two-dimensional (2D) cell culture. While these platforms are good for growing cells to be used later on, they are not ideal environments to monitor cell responses to stimuli as cells cannot freely move or perform the functions you would see in vivo.

Three-dimensional culture
Cell culture that takes place in a biologically relevant matrix, usually this involves cells being embedded in a hydrogel containing extracellular molecules (e.g. collagen), is known as three-dimensional (3D) cell culture. By adding an additional dimension, cell behavior is more representative of in vivo dynamics and cells can engage in more communication between neighboring cells or small molecules. These simplified 3D cell culture models can be combined in a manner that recapitulates tissue- and organ-level functions in devices known as organ-on-a-chip. In these devices, chambers or collagen layers containing different cell types can interact with one another for multiple days while various channels deliver nutrients to the cells. The advantage to these devices is that tissue function can be characterized and observed under controlled conditions (e.g. effect of shear stress on cells, effect of cyclic strain or other force, etc.) to better understand the overall function of the organ. While these 3D models do a better job to understanding organ functions on a cellular level over 2D models, there are still challenges. Some of the challenges include: imaging of the cells, control of gradients in static models (i.e. no perfusion system), and difficulty recreating vasculature. Even with these challenges, 3D models are better tools for studying and testing drug responses in pharmacological studies.

Revised article after peer review
Microfluidic cell culture

Microfluidic cell culture requires knowledge from biology, biochemistry, engineering, and physics as it attempts to develop devices and techniques for culturing, maintaining, analyzing, and experimenting in cells at the microscale.1 It merges microfluidics, a set of technologies used for the manipulation of small fluid volumes (μL, nL, pL) within artificially fabricated microsystems, and cell culture, which involves the maintenance and growth of cells in a controlled laboratory environment. 2,3 Microfluidics has predominantly been used for cell biology studies as the dimensions of the microfluidic channels are well suited for the physical scale of cells.4 A key component to microfluidic cell culture is being able to mimic the cell microenvironment which includes soluble factors that regulate cell structure, function, behavior, and growth.4 Another important component for the devices is the ability to produce stable gradients that are present in vivo as these gradients play a significant role in understanding chemotactic, durotactic, and haptotactic effects on cells.4

Some considerations for microfluidic devices relating to cell culture include: fabrication material (e.g. PDMS), culture region geometry, and a control system for delivering and removing media when needed using passive pumping or a flow-rate controlled device. Fabrication material is crucial as not all polymers are biocompatible, with some causing undesirable adsorption or absorption of small molecules. As an alternative to the commonly used PDMS, which can be harmful for the aforementioned reasons, there have been  advances in the use of thermoplastics (e.g. polystyrene) as a replacement materials.5,6

Critical aspects to controlling the microenvironment include: cell seeding density, reduction of air bubbles as they can rupture cell membranes, evaporation of media due to an insufficiently humid environment, and cell culture maintenance (i.e. regular, timely media changes).

Advantages

Some of the major advantages to microfluidic cell culture are reduced sample volumes (especially important when using primary cells) and the flexibility to customize and study multiple microenvironments within the same device.3 Given the small dimensions in microfluidics, laminar flow can be achieved, allowing manipulations with the culture system to be done easily without affecting other culture chambers.7 Microfluidics also allows for non-dividing or slow dividing cells to be cultured continuously and quicker than traditional culture methods (e.g. flasks, dishes, or well plates) due to the smaller sample volumes.1,7

Rough Draft
Microfluidics refers to a set of technologies used for the manipulation of small fluid volumes (μL, nL, pL) within artificially fabricated microsystems. Cell culture refers to the maintenance and growth of cells in a controlled laboratory environment. Cell culture using microfluidics requires knowledge from biology, biochemistry, engineering, and physics as it attempts to develop devices and techniques for culturing, maintaining, analyzing and experimenting in cells at the microscale. Microfluidics has predominantly been used for cell biology studies as the dimensions of the microfluidic channels are well suited for the physical scale of cells. A key component to microfluidic cell culture is being able to mimic the cell microenvironment which includes soluble factors that regulate cell structure, function, behavior, and growth. Another important component for the devices is the ability to produce stable gradients that are present in vivo as these gradients play a significant role in understanding chemotactic, durotactic, and haptotactic effects on cells.

Some considerations for microfluidic devices relating to cell culture specifically includes: fabrication material (e.g. PDMS), culture region geometry, and a control system for delivering and removing media when needed using passive pumping or a flow-rate controlled syringe pump. Fabrication material is crucial as not all polymers are biocompatible, with some causing undesirable adsorption or absorption of small molecules. There has been some advances in the use of thermoplastics (e.g. polystyrene) to replace the commonly used PDMS. Critical aspects to controlling the microenvironment include: cell seeding density, reduction of air bubbles as they can rupture cell membranes, evaporation of media due to an insufficiently humid environment, and cell culture maintenance (i.e. regular, timely media changes).

Advantages
Some of the major advantages to microfluidic cell culture are reduced sample volumes (especially important when using primary cells) and the flexibility to customize and study multiple environments within the same device. Given the small dimensions in microfluidics, laminar flow can be achieved, allowing manipulations with the culture system to be done easily without affecting other culture chambers. Microfluidics also allows for non-dividing or slow dividing cells to be cultured continuously and quicker than traditional culture methods (e.g. flasks, dishes, or well plates) as the volumes are considerably smaller at the microscale.

Addition to Article - HPLC
original:

"Detectors
HPLC most commonly uses a UV-Vis absorbance detector, however, a wide range of other chromatography detectors can be used. A universal detector that complements UV-Vis absorbance detection is the Charged aerosol detector (CAD). A kind of commonly utilized detector includes refractive index detectors, which provide readings by measuring the changes in the refractive index of the effluent as it moves through the flow cell. In certain cases, it is possible to use multiple detectors, for example LCMS normally combines UV-Vis with a mass spectrometer."

edit:

Detectors
addition to beginning of paragraph: "HPLC detectors fall into two main categories: universal or selective. Universal detectors typically measure a bulk property (e.g. refractive index) by measuring a difference of a physical property between the mobile phase and mobile phase with solute while selective detectors measure a solute property (e.g. UV-Vis absorbance) by simply responding to the physical or chemical property of the solute. " HPLC most commonly..

Article Evaluation

(https://en.wikipedia.org/wiki/High-performance_liquid_chromatography) Text Posted to Article's Talk Page Initial Planning for Article
 * relevant material/subheadings for the overarching topic
 * article seems neutral with no bias to any particular method/technique
 * nformation is good, fewer references than expected for a heavily researched topic
 * other applications (e.g. microscale fabrication) not mentioned much
 * some subtopics (e.g. particle diameter, pore size) underrepresented
 * citations are varied in discipline and wide range of years
 * some links to citations work
 * talk page references need for clarity and simplification
 * B class rating w/low importance/WikiProjects Chemistry
 * Some subtopics (e.g. particle diameter, pore size) could be expanded upon for examples and benefits/drawbacks for each. Also discussing trends in terms of how that effects the resulting chromatogram and throughput for the instrument. References could also be added throughout the article as HPLC is a well-studied analytical instrument. Tvanneel (talk) 05:39, 17 January 2018 (UTC)
 * Cell culture using different methods in microfluidics


 * hydrogels
 * digital microfluidics
 * etc.
 * (https://en.wikipedia.org/wiki/Microfluidic_cell_culture)
 * work in progress for sources