Surface plasmon resonance (SPR) has been around for more than 20 years, yet many researchers still rely on outdated techniques to characterize biological interactions because of the cost and complexity of SPR analysis. Now that SPR technology is becoming more affordable and accessible, it is important for researchers to understand the value that SPR data can add to their research. We believe that SPR will become a standard technique available in every single biochemistry lab because it uncovers the true nature of binding interactions.
1. Get deeper insight into your interactions – Real-time monitoring
The key to many research projects is understanding the binding interactions amongst biomolecules. Most common techniques like western blots, pull-down assays and co-immunoprecipitation can only tell you if binding is occurring or not. This is very limited information, as many things in the biological world interact to some degree. Some techniques like ELISA can give you a bit more detailed information such as the binding affinity, but not without complicated and time consuming labeling steps. To fully characterize an interaction, you need to look at what is happening in real time – the binding kinetics of the interaction. Surface plasmon resonance gives you this data, exposing more than just the tip of the iceberg by providing deeper insight into your interactions. Detailed information such as on and off rates are what lie beneath the surface of yes/no binding and affinity values, and are critically important to fully understanding the biological system that is being studied.
2. Forget the label – Label-free detection
Imagine a world with no labels….well, with surface plasmon resonance, you can. One of the main features of the SPR is the ability to measure the interaction between your analyte and ligand without spending the time and money on expensive labelling reagents and protocols. Forget radioactive and fluorescent labels forever. With SPR you don’t need to wonder whether a label is affecting the native functionality or behavior of your biomolecules.
3. Save precious samples – Small sample sizes
Surface plasmon resonance requires minimal amounts of sample for binding kinetics experiments. This means having to express, purchase, and/or purify less sample than other techniques like ITC. Expressing and purifying proteins is time-consuming, but alternatively, purchasing proteins can get expensive. Many proteins are also not available for purchase. With small sample volumes, sample preparation for SPR is less time-consuming and more affordable.
4. Avoid wasting consumables – Reusable sensor chips
Sensor chips for surface plasmon resonance experiments can be reused, lowering the cost of consumables. Regeneration buffer can be used to disrupt the interaction between the analyte and ligand, meaning that the sensor (with the ligand attached) can be reused. The amount of times you can reuse the sensor chip with the ligand attached depends on the stability of the ligand. Certain sensor chips can also be reused with a new ligand as well. For example, NTA sensor chips can be fully regenerated and used with many different ligands.
5. Purification is not always necessary – Complex samples
Using purified sample is always ideal for experiments, but sometimes this is not possible. Surface plasmon resonance can be used to test crude samples for applications such as serum analysis. Avoiding the time and cost associated with purifying samples can be a major advantage compared with other techniques.
6. Get accurate results – Repeatable measurements
The ability to replicate experiments can often become a challenge in research. Surface plasmon resonance technology will give you confidence in the accuracy of results, as replicate injections of sample consistently show repeatable results.