Author: Tucker Burgin

Due to blog troubles yesterday, we have chosen to upload this post as a .pdf: Nanoporoustentwettingfluorescenceinconclusive

This is a followup to my previous post, which can be found here. Previously I reported that fluorescein diphosphate (FDP) incubated on the surface of an NPN chip would adhere well enough to be visible on the membrane after gentle washing and treatment with a fluorescence-activating enzyme (alkaline phosphatase, AP.) I also reported that pre-incubation…

You may recall that last year I spent some time working on a proof-of-concept experiment for a high-throughput, non-specific drug discovery assay. The experiment involved binding up a FLAG-peptide sequence-tagged alkaline phosphatase (AP) enzyme with a biotinylated anti-FLAG antibody, in turn bound to a large avidin bead. This very large complex was unable to move…

Lately I’ve been working on building computational models which can be used to make predictions about the behavior of a diffusion experiment, to allow for the collection of large pools of data without the difficulty and time consumption associated with actually performing an experiment. This could prove to be a valuable tool for the continued…

Update 8/15/14: Replaced the plots with updated versions including more data for NPN (now n = 3) and cellulose (n = 4,) as well as new high-flux polyethersulfone membrane data (n = 3.) I also dropped one clearly erroneous datapoint from the NPN dataset to dramatically cut down the standard deviation. — This is a followup…

This is a followup to my previous post, found here. Some of the data in that post is now outdated and will be replaced with newer data here. I’ve added to the comparison the diffusion of cytochrome C and urea through a polyethersulfone “high-flux” membrane. This material is commercially available just like the cellulose triacetate….

UPDATE: Some data presented here is out of date. For up-to-date data, see my next post here. — Lately I’ve been performing comparison experiments between our NPN membranes (wafer 1132, 3 slot SEPCON, 40-48nm pores and 13-20% porosity) and commercial cellulose triacetate filtration membranes, with respect to the degree to which they hinder the diffusion…

For a while now I’ve been running diffusion experiments using bacterial alkaline phosphatase (bAP) as my solute of interest in a solution of 50mM tris buffered saline (TBS) and 20 ug/mL BSA. Initially, the BSA was included as a way of reducing the adsorption of the low concentrations of bAP to the device surfaces —…

See my previous post for background information. It has been established that diffusion of small particles (diameter < roughly 1/3 pore diameter) across ultrathin membranes is mediated almost entirely by the ability of the particle to discover a pore, rather than by its ability to diffuse through a pore once one has been found. In…

For a while now I’ve been working on developing and testing the practicality of using nanoporous membranes as filters for highly sensitive assays. Traditional filter-based assays are restricted in their speed by both the time it takes for a particle to find a pore as well as the time it takes for the particle to…