Introduction As a continuation of my rotation project and a beginning to my PhD work in the McGrath lab, I wanted to finalize my shear stress calculations within our blood vessel microfluidic device. All previous shear stress calculations were purely analytical, with many assumptions. This work aimed to minimize those assumptions while providing some publishable…

Just a quick update on my status: I got the NPN pre-filters from Greg in Montreal and finished testing 15 of them last week, so this week I will start doing additional experiments. I plan to explore the size separation capabilities in KCl, which should give even tighter distributions than LiCl. I don’t plan on…

This is my (Jim) summary of the results thus far for NPN vs NPN-O and Front Side/Back side comparisons. More to come … *************************************************************************************************************   As thesis indicated, the thicker membrane is, the larger average pore size will be. From my process, the average pore size for 50nm membrane is between 9nm and 10nm; the…

Separation of Nanoparticles using surface acoustic radiation force:  Surface acoustic waves (SAW) can be defined as mechanical waves which propagate on the surface of an elastic medium which most of its energy is concentrated in the surface. It’s been used in many different biological applications such as separation of cells, tumor cells, microvesicles, nano and…

Having generated some tomograms of various Au, NPN, and MgF2 nanostructures in the past months, I should be able to parameterize these structures. I have many questions about how the nanostructures actually effect SERS performance. In general, we can use these methods to more accurately and precisely describe our nanomembranes. Hypothetical Factors Surface Roughness ~=…

I’ve received some of the very first MgF2 material that I produced way back when and shipped off to Nottingham. These chips were produced from NPN wafer 1085 (5-slots). There are a few membranes still remaining, but mostly the chips are in tatters.       Tomogram Reconstruction Weighted Back Projection (quick and dirty) We…

Thanks to Kilean for the TEMs. One of the properties that influences strong SERS behavior is surface roughness; rougher metals produce a better SERS effect. People have electrochemically roughened surfaces before to make better SERS sensors. The following quote is from a review paper (SERS Materials Review Paper, 5 years old now) After decades of debate,…

Another set of images of both sides of a membrane, this time something weird is happening… It looks as though I’m missing some holes from the top side. They looked to be filled in but are not when seen from the back. Here is the backside of the wafer showing a bunch of holes. (the…

While JK has been processing backside images from 50 nm, 75 nm, and 100 nm membrane SEM images for pore information, I thought I’d take a look at a 100 nm membrane from both the front and the back at the same spot. Here are the images referenced to a corner of the trench. The…

These are the sieving curves for 50, 75, and 100 nm NPN membranes. The 75 nm NPN 30 nm gold data point is just an estimate, since the membrane broke before enough filtrate could be collected for an absorbance measurement. However, our estimates of zero gold tend to be pretty good (gold is very visible in solution,…