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DiPIA / Can CFCA be run on Sensor Chip™ Protein A? YES
« Last post by GE Marie W on January 18, 2016, 07:53:44 AM »
Can CFCA be run on Sensor Chip™  Protein A?
Yes, it is possible to run CFCA on Sensor Chip Protein A and completely rely on the results if the sample is diluted 1:100 or more in running buffer. For less dilution, if any bulk effect is observed, the CFCA results must be treated with caution and it is up to the user to assess the quality of the data.
Ideally, a blank reference surface and blank subtractions are recommended for CFCA since subtraction of signals on the reference surface allows for compensation for non-perfect match of sample and running buffers (i. e., for bulk refractive index effects), whereas subtraction of buffer signal corrects for the assay drift.
On Sensor Chip Protein A, however, it is not possible to use a blank reference surface and therefore bulk compensation cannot be done. However, since the dynamic range of CFCA for proteins allows for the concentration determinations in the nanomolar region, sample is most often greatly diluted (≥ 100 times) in a running buffer before the measurement and any bulk effect can be disregarded and the CFCA results considered reliable.
DiPIA / Tips of the day for Biacore S200!
« Last post by GE Marie W on January 11, 2016, 04:44:25 AM »
Did you know that Biacore™ S200 provides improved functionality on copying graphs and allows also adjustment of curve thickness and sensorgrams colour. This simplifies transfer of results into Power Point or Word, for example.
  • Right click and choose: Copy Graph - Small, Medium or large (all with suitable font sizes)
    Rick click and choose: Curve appearance
and then adjust curve thickness and sensorgram colour.

When analyzing small molecules and fragments, poor blanks can ruin the experiment. A practical way to avoid contamination in glass ware that could give rise to unspecific binding in blanks (such as small rests of detergents) is to wash the glassware carefully with 50 mM NaOH followed by MilliQ water before use.

 (If possible, avoid using dishwasher for your glassware when  working with small molecules).

/GE Veronica
DiPIA / Sensorgram Comparison, Min/Max limits, one is straight the other not
« Last post by GE Asa on December 17, 2015, 02:07:22 AM »

using the sensorgram comparison functionality in most cases standard deviation will be used since the standard sensorgrams experimental variation will be evenly distributed. The deviation plot is then constructed by subtracting the average curve from all data and divide by one SD (the average curve itself becomes a straight line at zero) and the limit senorgrams become straight lines at the set SD value. The data handling is symmetrical for upper an lower limit.

But if the standard sensorgrams are not randomly distributed (different batches/lots of the standard for instance) Min/Max can be used instead. And then suddenly only one (the lower) of the limit sensorgrams will be straight in the deviation plot, whereas the upper will vary. As the data is no longer symmetrical (a median is used), developing this functionality it was decided to use the lower limit distances to the median for transfer to a deviation plot. So this is used for all data, also data on the "up side". The lower limit will then be straight whereas the distance from the upper limit sample data points to the median can still differ because of the asymmetry.

I have no idea if this makes any sence at all, but you can always look in the Software handbook to get a  more stringent explanation.

Best wishes,
In the Biacore S200, there is a new ABA-injection command which can be used with and without competitor. If you have a competitor to your LMW/fragment you can confirm the binding by testing with and without the competitor. See attached picture - how it works!
DiPIA / Re: Capture of goat and rabbit antibodies
« Last post by GE Asa on December 02, 2015, 01:09:58 AM »

the Protein A chip can be used for the rabbit antibodies (note that with protein A in rare cases, for any species, certain antibodies bind less well).

For the goat antibodies Protein G should work well, and give stable capture. Protein G can be amine coupled using pH 4 and regenerated with 30 s of 10 mM glycine, pH 1.5.

Best wishes,
DiPIA / Applications of SPR for Detection of Bispecific Antibody Activity
« Last post by GE Marie W on December 01, 2015, 04:53:59 AM »
Very interesting article - Applications of Surface Plasmon Resonance for Detection of Bispecific Antibody Activity
BioPharm International, October 2015
By Robert Karlsson, Senior Staff Scientist of Protein Analysis Applications
DiPIA / Capture of goat and rabbit antibodies
« Last post by Rick on November 30, 2015, 04:18:33 AM »

I have been using your kit for capturing mouse antibodies but now have some goat and rabbit antibodies. Any suggestions how to get a capture assay for those?

Best regards,
DiPIA / Microplates for DMSO containing solutions
« Last post by GE Anna M on November 24, 2015, 01:32:51 AM »
Hi! I recently had a question from a customer asking me if it is OK to run LMW/fragment screening assays with DMSO using micro plates made of polystyrene.The answer to that question is no. DMSO solutions are not compatible with polystyrene. When DMSO comes in contact with polystyrene it will extract components from the plastic that could disturb your experiments. You could actually see binding from these components to your surface. For experiments involving DMSO, always go for polypropylene materials for your plates and vials. A simple tip that will make your day a lot easier!  ;)

DiPIA / Re: Forgotten how to startup and prepare a Biacore system for use?
« Last post by GE Marie W on November 23, 2015, 05:45:24 AM »
Just so you know...there is also a video for Biacore X100 on how to get started, also on youtube!!!!
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