A Flotation Method for Studying Physical Binding between Lipid Droplets and Mitochondria

Lipid droplets (LDs) are ubiquitous organelles that serve as central hubs for cellular lipid metabolism. Disrupted LD–mitochondria association can impair fatty acid transfer, reduce cellular energy production, and increase lipotoxicity, thereby promoting metabolic disease progression. Current imaging-based approaches for studying LD–mitochondria contacts have inherent limitations, including limited resolution, probe dependence, difficulty in tracking dynamic interactions, and reliance on indirect evidence. Here, we describe a centrifugation-based flotation method for directly assessing the physical binding between LDs and mitochondria. This simple and robust method can also be adapted to study interactions between LDs and other membrane-bound organelles under physiological and pathological conditions.