Dysregulated interactions between biomolecules can lead to changes in cell signalling and gene expression, both common drivers of human disease. A detailed understanding of these interactions is vital for drug development, often targeting such interactions for therapeutic effects. In this project, I aim to develop an optical microscopy tool to observe interactions of highly diverse biomolecules in terms of e.g. weight or size, in real-time on a single-molecule level without the use of labels or immobilization, which limits many current established methods. This will allow the study of dynamic interactions between complex biomolecules of varying sizes and with a wide range of properties. The tool will be capable of researching various biological systems that are not easily accessible by established methods. This could contribute to breakthroughs in the research of severe diseases such as diabetes mellitus, Alzheimer's, or Parkinson's disease.