Hello,
I recently formulated bovine serum albumin nanogel with primary amine reactive protein crosslinkers. As I bmentioned in the title, I am using 90 plus brookhaven particle size analyser to measure the size of protein nanogel.
even though kcps values were around 4 to 5, when I measured pure bovine serum albumin in PBS solution (2mg/ml), I could obtain around 7nm as an effective diameter, which was very reliable.
However, when I measured my nanogel samples, the effective diameter changed drastically from around 200nm to 100000nm, not to mention that the kcps values were still single digits.
After formulating nanogel I filter the sample through 100k amicon filter.
I followed dls sample preparation method and tries to keep my sample as clean as possible by filtering them with 0.45um filter.
I checked my cuvette with polymer nanoparticle samples, but the size was similar to that of TEM images. I am attaching my TEM image in the hope of receiving detailed advice.
Thank you for reading and have a nice day.
It looks very much that you are generating a protein nanogels with a huge polydispersitiy. The question is then: How meaningful is a size measurement? Also your treatment with amicons and syringe filter will infleunce the size distribution. I would rather work on the optimization of your synthesis to get more defined BSA NP.
What is polydispersity index of your nanoparticles? DLS is strongly affected by the presence of aggregates, even by low amount of microparticles. filtration with 0.45 filter can affect size of nanoparticles. You can try low speed centrifugation (you can try different speed from about 500g to 4000g for several minutes for 1 ml samples) instead of filtration. we work with magnetic NPs and remove agregates by cf 1600g 5 min. Sonication for several minutes is also an option
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