Effects of defective motors on the active transport in biosensors powered by biomolecular motors

Abstract

Motor proteins, such as myosin and kinesin, are biological molecular motors involved in force generation and intracellular transport in living cells. They were proposed to drive molecular shuttles for the active transport of analytes, thus significantly accelerating the sensing process of biosensors. Integrating motor proteins into biosensors requires their immobilisation on the operating surfaces. However, this process makes some motor proteins defective, slowing analyte detection. Here, we investigated the movements of molecular shuttles on surfaces in the presence of active and defective motors using a Brownian dynamics simulation, and elucidated the effects of defective motor proteins on the transport efficiency of the shuttles. We found that the motility of shuttles depends on the fraction of active motors relative to defective ones and that over 90% of the surface-bound motor proteins must remain active for efficient transport. The high fraction of active motors required for efficient transport can be attributed to the difference in the binding lifetimes of active and defective motors to shuttles. These results provide insights into how motors accumulate on sensor surfaces and set a guideline for the choice of polymer materials for biosensors powered by motor proteins.