Hi,

Here's a protocol I used successfully for immobilization of 100 nm Liposomes on a Sensor Chip L1 using a Biacore X100.

1) Clean your Biacore by running Desorb or Desorb and Sanitize with an overnight run using Water

2) Running buffer: HBS-N (no detergent for obvious reasons)

3) Immobilize 2 mM DMPC liposomes in HBS-N on control flow cell for 300 s at 5 µL/min

4) Immobilize protein/receptor bearing liposomes (2 mM) in HBS-N on measurement flow cell for 300 s at 5 µL/min

5) Block both flow cells with 0.1% BSA in HBS-N for 120 s at 10 µL/min

6) Inject your samples

7) and 8) Two regenerations: first 0.5% SDS for 30 s at 10 µL/min, second 20 mM CHAPS for 30 s at 10 µL/min

9) Extra wash with HBS-N

This conditions lead to immobilization levels between 6000 and 8000 RU, so the surface war saturated.

Think about your negative control flow cell when performing your experiments to make sure you are measuring biologically relevant signals!

The L1 chip is pretty robust and reproducible. If you fail to immobilize significant amounts of liposomes, something might be wrong with your samples, not the sensor chip. As a positive/negative control, prepare liposomes and immobilize those to see if the assay works.

Hope this helps!

Daniel

Thanks Daniel !

I am using lipoparticles generated from a stable cell line, their structure include a solid core protein surrounded by intact plasma membrane. I was able to immobilize them on L1 chip but couldn't saturate them membrane in 10 min injection at 5uL/min. I was able to attain immobilization levels of 2600 - 2800 RU and the curve was not plataeuing in 10 minutes. I have to make my sample more concentrated to try and overcome this.

I am using HEPES as running buffer, I am using lipoparticles generated from wild-type cells to use in the control flow cell. I block both the flow cells with a quick 2 min injection of 0.2% BSA @ 10uL/min.

I am searching for a technique to estimate the protein/lipid ratio of these lipoparticles, and to approximate the mass of these particles. This information will help me to aim for a certain immobilization level.

let me know what you think.

Thanks again for sharing your protocol. Much appreciated.

Thiru

Hi, 

This review might be helpful, it repertories some technics to immobilize lipids on SPR chips : http://www.sciencedirect.com/science/article/pii/S0009308406000326

Benjamin