12 replies to this topic

[b_agnes]

Hi everyone

has anyone tried using an expired (approx. 9 months ago) Gene Expression Hyb kit (Agilent)? I'm aware that it is still cheaper to buy a fresh one than to waste a microarray slide, and it is officially not recommended, but if it could be OK (components stored properly, like the redissolved Blocking Agent at -20C), it would be nice to use it...
Thanks for any advice.

[aimikins]

not that kit in particular, but I've always used things expired, even up to a few years, and usually they're ok.  sensitive reagents like peroxides and some enzymes, this doesn't apply.

hmm...tough call for you. I bet the kit's still fine, but nothing's a bigger waste of time and money than an experiment that has to be repeated.

[gogreen]

Hi b_agnes,

if the components are stored well it should be good. I have tried with some old stuff and it used to work without any problem. If u have more of the lyophilized blocking agent, redissolve them...or use the one stored at -20.
The fragmentation buffer and hyb buffer are quite stable and can be used at a later time without any problem

[b_agnes]

Hi gogreen,

thanks a lot! This helped me to decide and I'll give it a go! Fingers crossed!

agnes

[gogreen]

Hi agnes

DISCLAIMER
You're doing it at your own risk. I cannot guarantee the success


all the best

Edited by gogreen, 02 December 2009 - 04:43 AM.

[mdfenko]

i recently finished off a kit that expired in november 2008 and it worked well until the last drop.

i am currently using a kit that expired the end of march and another that expired in july (all agilent ge kits).

[Prep!]

with whatever i have observed till now.. i can in fact vouch with surity (only for the better companies) that the kits if stored in the proper storage conditions, work well till even after 6 months of their expiry. The R and D systems ELISA worked for me even after 1 and a half years of expoiry!!!
Best luck!!!! i m sure it will be fine!!
do tell us wat happened!!??!!

[b_agnes]

Thanks everyone for sharing the experiences, I'll definitely try it and will let you know how it went (maybe in January only as I have a long Christmas holiday )
all the best!

[gogreen]

Hi Agnes, Are you going to use pretty old arrays too with the old buffers??

[b_agnes]

They were manufactured a bit more than a year ago. Why do you ask? I hope it doesn't add an extra risk factor...

[gogreen]

Sadly, it does add one more risk factor!!

The results which I got using arrays which were stored for over a year and a half from the date of receipt of arrays, were not quite promising...I think it affects the slide chemistry and after hybridization the probes looked stripped! I was just trying a hyb on a very old array just out of curiosity and it turned out to be bad(The arrays were stored dessicated at dark as per recommendations). So if you are using arrays which came long time ago and get a bad result, its likely to be because of the bad array than the bad reagents!

Edited by gogreen, 06 December 2009 - 05:55 AM.

[b_agnes]

I just scanned the slide yesterday and I can say it looks alright! The analysis is not done yet but based on the pictures I got neither the expired kit nor the array was bad!   I suppose, the array quality can be quite different depending on the manufacturer and the printing technique etc... I used Agilent arrays - the storage box was dry but not airtight, only well wrapped, and apparently it still remained useable.

[gogreen]

Hi Agnes,

That is good news!!   I was talking about Agilent arrays too..For quite old arrays, you sometimes see some kind of degeneration of the probes..The probes are no more completely dense, they tend to show non uniformity in the spot pattern rather than showing a perfect circle. If the image looks good, it should be fine..