Bench Press - Latest Comments in Nanosensors: Taking Sensitivity to a New Level

Re: Nanosensors: Taking Sensitivity to a New Level

Mr. Gunn — Sat, 13 Sep 2008 15:10:19 -0000

It does seem rather unlikely that there won't be a correlation between pH and ionic concentration in clinically-interesting samples.

I'm sure they can make it work, but I wonder how well they can compete against the other nanosensing technologies using ring resonators or microcantilevers.

Re: Nanosensors: Taking Sensitivity to a New Level

BenjaminTseng — Fri, 12 Sep 2008 01:08:25 -0000

Mr. Gunn, that's a good point. This isn't my field, but I took a look at the Science paper that this finding was published in. It details two experiments which may be of interest to you:

- The researchers took "unmodified" nanowires and subjected them to a range of pH's from pH=2 to pH=9, and we see minimal impact in conductance until pH ~ 6 (around the Ka of the SiOH coating) when there was a more dramatic increase (due to the SiOH coating becoming de-protonated)
- The researchers designed a calcium ion sensor using Calmodulin attached to the nanowires, but use a negative control to show that the unmodified nanowires did not respond to changes in calcium concentration.

It would then seem that these nanowires are not sensitive to most ions, and are instead, only sensitive to pH. As I mentioned before, this isn't my field, so you'll have to let me know if that's highly unlikely.

Re: Nanosensors: Taking Sensitivity to a New Level

Mr. Gunn — Thu, 11 Sep 2008 12:32:53 -0000

Aren't nanowires extremely sensitive to ionic concentration? Won't that kill their sensitivity in whole blood?