Screening for adsorptions of Calbindin D9k and Monellin proteins to Silica nanoparticles

Sammanfattning: Although nanoparticles (NPs) are very small, their field in science is currently growing very large. There are several biological, medical and technical applications possible for NPs when bound to proteins. Protein-NP interactions are difficult to predict and therefore a lot of fundamental research is yet to be completed. This study is an attempt to contribute with the aim to explore the interaction between two different proteins with three different sizes of silica NPs. By fluorescence spectroscopy light have been shone on silica NPs and their interactive behavior in combination with three different mutations of the two proteins calbindin D9k and monellin respectively. The fluorescence intensity was measured with two different fluorophores; ANS and NR. The study considers six different scenarios of interaction to be possible. Dynamic light scattering measurements were carried out to complement the fluorescence screening results. Interaction appear to be occurring, particularly for the specific combination of the positively charged (+8) mutation of monellin and silica NP, which also indicate on protein concentration dependence. The NP size appear to have an impact on the concentration limits for (+8) mutation of monellin. The results of the experiments also indicate that ANS is a more suitable fluorophore than NR for fluorescence measurements on silica NPs.