Modifying buffer or solution components will impact the molecular scale behavior of proteins or polymers. Viscosity is a sensitive indicator of these changes. Utilizing simple models in combination with knowledge of the formulation components can support viscosity data interpretation and provide insight. Even a qualitative understanding of how interactions are varying and influencing stability and microstructure can help guide you in the right direction.
Download our webinar where we will present viscosity data of protein solutions in a variety of buffers and discuss options for interpretation.
There are some best practices when it comes to testing the solubility between two samples. You can do a quick visual solubility check by mixing the two into a new clean (dust-free) vial and checking the mixture. With this test, we recommend also leaving it together for at least a couple hours and if possible, at least one day to ensure proper miscibility.
Separately from this test, with samples such as protein, it may be easier to work with the buffer which your proteins are formulated with. In the cases with formulated proteins, since you are already aware of the buffer, using the buffer to clean, and then a detergent solution or a solution miscible with the buffer will ensure effective cleaning.
We recommend a minimum of three different shear rates when analyzing your samples to determine whether they are Newtonian or non-Newtonian. Separately, the shear rates should have a wide range. The reason for the wide range is because many are complex. Sometimes, your sample will not show shear thinning or shear thickening behavior at low shear rates but will at high shear rates.
Overall, there is just a lot to your sample that you may not know about until you actually test it. As a result, we recommend testing as much of a range as possible to ensure full knowledge of how your sample behaves.