What the DJ Does on Techno Night

That's actually not what electrospinning is. But it seems like it should be.

Electrospinning is a pretty neat process, and although I'm only vaguely familiar with the concept, I'm going to try to lay it out for you. So generally, electrospinning is a method for creating structured polymeric fibers with diameters in the range of several microns down to tens of nanometers. The fibers are formed from a liquid precursor solution, which is held in a reservoir and pushed into a capillary or needle (called the spinnerette), creating a droplet of the solution on the end of the spinnerette. A strong electromagnetic field is applied to the solution. Commonly this is created by applying a strong voltage to the spinnerette and a corresponding ground to a ground plate inside the electrospinning apparatus. If the electromagnetic field is strong enough, it overcomes the surface tension of the solution, deforming it into a conical shape. The solution then becomes a charged jet. The jet ejects from the spinnerette and moves toward the ground plate, pulling and subsequently charging more precursor from the reservoir, through the spinnerette, and into the electromagnetic field. This results in a continuous filament that moves about randomly in the electric field on its way to the ground plate, where it forms an electrospun mat of polymer fiber. The process is illustrated very nicely in an interactive Flash animation that has been generously shared publicly at Michigan Tech's Nanotechnology website. And an SEM image of electrospun fibers is shown in the image below (I stole this image from a former colleague's Epernicus page, which can be found here).


Electrospinning, and its close cousin electrospraying, have been around for many decades. But the process of electrospinning has seen a bit of a resurgence lately. During my doctorate work, I had several colleagues who successfully used electrospinning as a platform onto which a biosensor architecture could be applied. The high surface area of the micro- and/or nano-fibers was ideal for sensing applications.

If you're interested in learning more about electrospinning, I came across this paper (pdf), which appears to be available without a subscription. And as is usually the case, Wikipedia is a pretty good resource if you're looking to gain a basic understanding of the process. And of course you can find some really good links in the 'References' section of the Wikipedia page as well.

Beer? Liquor? I Say Both!

I'm taking a break today from the tedium of grant proposal writing, which I've been hard at all week. Instead of writing, I visited the MU campus to talk with my former advisor. And I've spent the rest of the day thus far drinking coffee, reading, and listening to community radio. It's a welcome break, though I find myself dwelling on the work I have ahead of me - as soon as I finish the rough draft of the proposal that I'm currently working on, I'll have to immediately start working on another. I also can't help thinking that it may have been a very bad idea to take a day off of writing, as it will set me back by a full day with a deadline looming ahead. But I'm trying to push these thoughts aside so that I can relax and enjoy my little hiatus.

Although I'd like to include in this post something science- or technology-related, I'm just not in the mood. I'm feeling more like rambling on about delicious cocktails or draft beers that I'd like to partake of this evening. For instance, I've been interested in trying a gin fizz, but I'm afraid it may be a bit too cold here in mid-Missouri for such a refreshing drink. I'm sure I'll think of something by time I reach the pub.

Anyways, I'm thinking my next post will focus on the process of electrospinning, as I've had colleagues in the past whose research involved electrospinning of polymers and organosilicates. In the meantime, I'll keep weighing my options on adult beverages. I recommend you do the same. It's Friday, after all.

I'm Not Oprah

And this isn't Oprah's Book Club. However, I thought I would share my current reading list. The following is a sort of rough reading schedule. Rarely is this my actual schedule during the course of a day, but over a period of a week or so, I normally get around to reading each of these resources at least a couple of times to stay up-to-date.

My morning at the office normally starts between 7:30 and 8, and comes with a big cup of coffee in my favorite hand-thrown Trotter mug. I start by checking my sister's Tumblr media blog, Liberry Cobbler, because it's always very entertaining. In fact, she's much more engaging than I, so I highly recommend this one. Next, I make my way over to Nobel-award-winning economist Paul Krugman's blog, The Conscience of a Liberal. His blog also has links to his most recent columns, and I always keep up with both.

Now, as far as science-y blogs go, of course Wired Magazine's science blog, Wired Science, is going to be where it's at. Somehow Wired has been able to amass an unprecedented number of hip, knowledgeable geeks, which I know sounds like an oxymoron, but it's true. Another science and tech blog that I can't necessarily recommend because I just added it to my reading list this morning is Pharyngula. This blog is authored by a biology professor at University of Minnesota-Morris, and is at the top of everyone's 'best' list. Seriously, just search for 'top science blogs' and you will be hard pressed to find a link that doesn't have Pharyngula listed in the top 5.

While we're on the subject of science reading, I should note that Lincoln University provides access to Elsevier's scientific database, ScienceDirect. This database includes some of the best journals in my field, including Biosensors and Bioelectronics and Sensors and Actuators. It's worth mentioning that I might be biased, as I have been featured in both of these publications. But hey, I never claimed to be objective here.

And because I enjoy all things bicycle- and cycling-related, I read Bike Snob NYC and CoMo CyCo, two very fine bicycle-themed blogs, everyday while I eat lunch. There are a few more blogs that I enjoy, but they are updated much less regularly. These include my mother's blog, A Room Without Books? No Way, and my good friend ButtDanceCity's media blog, KP the Nerdoscientist.

One Thousand Two Hundred And...Wait...Where Was I?

I've been working with a type of E. coli lately that is genetically modified to be non-pathogenic, or unable to cause disease. The project to detect the bacteria was already under way when I joined the team here at Lincoln University, but it was going relatively poorly. A colleague and I took over the project and analyzed all of the procedures and methods, as well as the results that were being gathered. Then, we rewrote the protocols that were being used. To be sure that the protocols that we wrote were the most effective, I have personally been either conducting or overseeing the various aspects of the project. Results have gotten better and the research project seems to be running much more smoothly. At this point, then, we're ready to begin matching the sensor data that we're gathering with actual concentrations of E. coli cells. But determining the concentration of a suspension of cells is not strictly an exact science.

Here's how it works. You take a certain volume of your cell suspension - for the sake of simplicity, let's choose a volume of 1 ml - and disperse the suspension onto some sort of nutrient-containing plate. In our work, we use polystyrene petri dishes with a nutrient-enriched agarose. The cell suspension spreads out over the agar and the bacteria stick to the surface, start feeding on the nutrients in the agar, and begin to divide and proliferate. As the cells reproduce, they do not move away from each other. Instead, they sort of remain stuck together. And as they continue to proliferate, they create a little cell colony. After a certain incubation time, say 24 hours, each viable cell on the plate gives rise to its own discreet colony. Then you go through and count the number of colonies on the plate. Let's say for example that you count 100 colonies on a given plate. Since you started with a volume of 1 ml, that means that your concentration is 100 CFU/ml, where CFU = colony forming unit.

But there's a bit of a problem with my example, because 100 colonies on a plate is not a realistic number. More likely, the number of colonies would be several-fold larger; possibly in the thousands. That's a lot of counting...1 colony, 2 colonies, 3 colonies, 4...

There are ways to make this process a bit easier. Probably the most obvious option would be to divide the plate into even sections. If you divide the plate into, say, 4 equal area segments, then you only need to count the number of cells in one of those segments and simply multiply that number by 4. Either way, though, it's not a lot of fun and I'm not looking forward to it.