User:Madisonmonahan/sandbox

Notes:

 * Incorrect citation in drug delivery section. Looks as though it was copied over from a paper (second sentence).
 * Biased “numerous advantages”. Overall favoring using this technique and comes off a litter persuasive.
 * Random information without going anywhere in last sentence of delivery section. Talks about how an experiment was done without going into the results. In general, a lot of random information like that that seems out of place.
 * Second section (absorption) vague and seems a little out of place. Also draws a conclusion about mechanisms from a single paper results.
 * Structured odd. Should put characteristics before data and mechanisms. They don’t explain (in depth) what the particles are until after they discuss uses.
 * References drug release but never truly discuss it in the article.
 * Whole advantage section—no references. Seems very bias.
 * References all seem solid but not very many. A lot of information in the article is supported only by a single source while the author states that several groups have gotten tried specific tests.
 * Article is a little out of date as no edits since August 2017 and no new information added to the article since January 2017.
 * Talk page has only one contribution about minor reference edits and complaining about references being pay to view so not very helpful in the betterment of the article.

Reflection Paragraph
The article Solid lipid nanoparticle provides general and useful information on lipid nanoparticles but could use some significant revision. The article came off a little bias in favor of using the nanoparticles for drug deliver vessels over other systems. It frequently discusses the advantages of using lipid nanoparticles but never mentions any disadvantages. Most conclusions were derived from a one reference per section, making the overall article seem very under referenced. Other issues were seen in the structuring of the article, discussing information such as uses and mechanisms for the particles before discussing what the actual particles are. There were also many instances where additional information was provided without much purpose, making the article hard to follow and seeming incomplete. Overall, the article could use significant restructuring and revision to add more references and cut out unnecessary information that just adds confusion to the reader.

Text Posted on the Talk Page
Why was the characteristics and production section introduced after the mechanism and application sections? I think it would read a little smoother to explain what the particles actually are before going into the details on how they work and could be used. A little more context on how they are used for drug delivery would also be very helpful.

Initial Planning of Article
The Droplet-based microfluidics article has a droplet manipulation section but is essentially completely lacking any information on formation methods used in droplet-based microfluidics. I would like to create a completely new section in the article for formation methods with subheadings for the different methods. In each method section, I will discuss the pros and cons for each method as well as common uses for a particular method. To decide which methods to mention, I will find formation methods that have at least 3-5 papers discussing the use of the method to ensure it is a well used and tested method. This should ensure that all information given in is relevant to the field.

Add to an Article
Another example of drug delivery using SLN would be oral solid SLN suspended in distilled water, which was synthesized to trap drugs within the SLN structure. Upon indigestion, the SLNs are exposed to gastric and intestinal acids that dissolve the SLNs and release the drugs into the system.

Lead section
This paragraph will give a brief summary of what the most common techniques used for droplet formation are and give the reader an idea of what they will see in the following paragraphs.

Method 1 (T-junction)

 * Overview of method
 * Applications
 * Example

Method 2 (Flow focusing)

 * Overview of method
 * Applications
 * Example

Other Methods

 * Overview of other less common methods
 * Novel methods not mentioned above
 * Applications/ unique uses of above applications that are distinct on their own

Article I emailed for Peer Review
In order for droplet formation to occur, two immiscible phases, referred to as the continuous phase (medium in which droplets are generated) and dispersed phase (the droplet phase), must be used ''. The size of the generated droplets is mainly controlled by the flow rate ratio of the continuous phase and dispersed phase, interfacial tension between two phases, and the geometry of the channels used for the droplet generation .'' Droplets can be formed in many different and very unique ways, both passively and actively. Generally, three types of microfluidic geometries are utilized for passive droplet generation: (i) Cross-Flowing, (ii) Flow Focusing, and (iii) Co-Flowing *. It is critical for all of these droplet formation methods that the solutions are acting under low Reynold’s number s to ensure laminar flow within the system. Each of the listed methods provide a way to generate microfluidic droplets in a controllable and tunable manner with the proper variable manipulation.

Cross-flowing Droplet Formation
           Cross-flowing is a passive formation method that involves the continuous and aqueous phases running non-parallel to each other. This method involves a variety of different structural possibilities such as a Y-junction but most common is a T-shaped junction with the dispersed phase bisecting the continuous phase. The dispersion phase bubbles into the continuous and is stretched until shear forces break off a droplet. In a T-junction, droplet size and formation rate are determined by the flow rate ratio and capillary number. The capillary number relates the viscosity of the continuous phase, the superficial velocity of the continuous phase, and the interfacial tension together. In all scenarios, the dispersion flow rate is always lower than the continuous flow rate. T-junction formation can be further applied by adding addition channels, essentially two T-junctions at one location. By adding channels, different dispersion phases can be added at the same point to create alternating droplets of different compositions.

Flow Focusing Droplet Formation
Flow focusing is a usually passive formation method that involves the dispersion phase flowing to meet the continuous phase at a slight angle then undergoing some sort of constraint that creates a droplet. This constraint is generally a narrowing in the channel to create the droplet though symmetric shearing, followed by a channel of equal of wider size. As with cross-flowing, the continuous phase flow rate but always be higher than the dispersion phase flow rate. The size of the droplets can be increased by decreasing the flow of the continuous phase, which in turn would also increase the frequency. Flow focusing can also be an active method with the constraint point being adjustable using pneumatic side chambers controlled by compressed air. The movable chambers act to chop the flow, deforming the stream and creating a droplet with a changeable driving frequency.

Co-Flowing Droplet Formation
Co-flowing is a passive droplet formation method that has the dispersion phase channel surrounded by continuous phase. At then end of the dispersion phase channel, the fluid is stretched until it breaks from shear forces and forms droplets either by dripping or jetting. Dripping occurs when the dispersion phase is flowing slower than the continuous phase, dripping into the channel. Jetting occurs, by widening or stretching, when the continuous phase is moving slower, creating a stream from the dispersion channel opening. Under the widening regime, the stream eventually widens and creates a droplet of a larger diameter. Under the stretching regime, the stream narrows and creates a smaller droplet. The effect of the continuous phase flow rate on the droplet size depends on whether the system is in a stretching or widening regime.

Reflective Essay
(1) For the Wikipedia article assignment, I worked of the formation of droplets in droplet-based microfluidics. This article is an addition to the main page for droplet-based microfluidics where there currently is only a paragraph on the topic. I will be adding a distinct section within the main page, separate from the current paragraph that is within the lead section of the page. (2) My main contributions to the droplet-based microfluidics page include:

·     A quick summary of formation techniques and why they matter

·     An in-depth look at cross-flowing droplet formation

·     An in-depth look at flow focusing droplet formation

·     An in-depth look at co-flowing droplet formation

(3) I responded to the peer reviewers in several ways but did not get any input from Wikipedia content experts or from other Wikipedians outside the course. In response to peer reviews I did the following:

·     Minor revisions to wording and structural issues

·     Clarification of what is meant by passive versus active droplet formation as well as explain why passive is more commonly used

·     Explained stretching versus widening better in addition to how the two are controlled and determined

·     Added discussion of analytical parameters (sensitivity, accuracy, and more) at the end of each technique paragraph for better comparison of the techniques

(4) Overall, I thought the assignment was a very valuable experience. The large reference requirement paired with the need to be concise helped reduce unnecessary wordiness and promote critical evaluation of sources. The peer review was helpful to receive as most of the suggestions greatly improved the quality of the article. I think it was valuable to give peer reviews since it not only gave us a chance to think critically about writing but also gave a more in-depth understanding of other areas within the class. The assignment was good learning tool for detailed learning but people whose topics may not have been discussed yet when we picked were at a slight disadvantage as they had more fundamental research to do before they could start writing. As for as the Wikipedia platform, I like the idea of teaching us how to add to Wikipedia in hopes of improving the site in the future. However, I found many of the trainings very unnecessary as the topics covered were often common sense or pretty easy to figure out on your own. In summary, the assignment as a whole was very beneficial but some of the Wikipedia trainings were a little redundant and it may have been helpful to add a brief summary to topics not yet discussed in lecture before topic selection.

Revised Article after Peer Review
In order for droplet formation to occur, two immiscible phases, referred to as the continuous phase (medium in which droplets are generated) and dispersed phase (the droplet phase), must be used[2]''. The size of the generated droplets is mainly controlled by the flow rate ratio of the continuous phase and dispersed phase, interfacial tension between two phases, and the geometry of the channels used for the droplet generation[3].'' Droplets can be formed both passively and actively[4]. Active droplet formation often uses very similar devices to passive formation but requires an external energy input for droplet manipulation.* Passive droplet formation tends to be more common than active as it produces similar results with simpler device designs. Generally, three types of microfluidic geometries are utilized for passive droplet generation: (i) Cross-Flowing, (ii) Flow Focusing, and (iii) Co-Flowing[5].  It is critical for all droplet formation methods that the solutions act under low Reynold’s numbers to ensure laminar flow within the system[6]. Droplet size is often quantified with coefficient of variation (CV) as a description of the standard deviation from the mean droplet size. Each of the listed methods provide a way to generate microfluidic droplets in a controllable and tunable manner with proper variable manipulation.

Cross-flowing Droplet Formation
          Cross-flowing is a passive formation method that involves the continuous and aqueous phases running at an angle to each other[7]. Most commonly the channels are perpendicular in a T-shaped junction with the dispersed phase intersecting the continuous phase[8]. The dispersion phase bubbles into the continuous and is stretched until shear forces break off a droplet[9]. In a T-junction, droplet size and formation rate are determined by the flow rate ratio and capillary number[10]. The capillary number relates the viscosity of the continuous phase, the superficial velocity of the continuous phase, and the interfacial tension[3]. In all scenarios, the dispersion flow rate is always slower than the continuous flow rate. T-junction formation can be further applied by adding additional channels, creating two T-junctions at one location. By adding channels, different dispersion phases can be added at the same point to create alternating droplets of different compositions[11]. Droplet size, usually above 10 μm, is limited by the channel dimensions and often produces droplets with a CV of less than 2% with a rate of up to 7 kHz.

Flow Focusing Droplet Formation
Flow focusing is a usually passive formation method that involves the dispersion phase flowing to meet the continuous phase at a slight angle then undergoing some sort of constraint that creates a droplet[12]. This constraint is generally a narrowing in the channel to create the droplet though symmetric shearing, followed by a channel of equal or wider size[13]. As with cross-flowing, the continuous phase flow rate will always be higher than the dispersion phase flow rate. Decreasing the flow of the continuous phase can increase the size of the droplets. Flow focusing can also be an active method with the constraint point being adjustable using pneumatic side chambers controlled by compressed air[15]. The movable chambers act to pinch the flow, deforming the stream and creating a droplet with a changeable driving frequency. Droplet size is usually around several hundred nanometers with a CV of less than 3% and a rate of to several hundred Hz to tens of kHz.

Co-Flowing Droplet Formation
Co-flowing is a passive droplet formation method that has the dispersion phase channel enclosed inside a continuous phase channel[16]. At then end of the dispersion phase channel, the fluid is stretched until it breaks from shear forces and forms droplets either by dripping or jetting[17]. Dripping occurs when capillary forces dominate the system and droplets are created at the channel endpoint. Jetting occurs, by widening or stretching, when the continuous phase is moving slower, creating a stream from the dispersion channel opening. Under the widening regime, the dispersed phase is moving faster than the continuous phase causing a deceleration of the dispersed phase, widening the droplet and increasing the diameter [18]. Under the stretching regime, viscous drag dominates causing the stream to narrow and creates a smaller droplet. The effect of the continuous phase flow rate on the droplet size depends on whether the system is in a stretching or widening regime thus different equations must be used to predict droplet size. Droplet size is usually around several hundred nanometers with a CV of less than 5% and a rate of up to tens of kHz.