An important scientific advance has been made by researchers at the Center for Advanced Biomolecular Recognition of the Korea Institute of Science and Technology (KIST)led by Dr. Youngdo Jeong, who created biological nanomachines to kill cancer cells.
The team focused on the study of the hierarchical structure of proteins, in which the axis of the large structure and the mobile units are hierarchically separated. With that they showed that only specific parts can move around the axis. Most of the existing nanomachines have been designed so that the moving components and the axis of the large structure are present in the same layer. Therefore, these components are subjected to simultaneous movement, which complicates the desired control of a specific part.
The Korean scientists then fabricated a hierarchical nanomachine by synthesizing and combining 2nm-diameter gold nanoparticles with molecules that can fold and unfold depending on the surrounding environment. This nanomachine was composed of mobile organic molecules and inorganic nanoparticles to function as large spindle structures and defined movement and direction in such a way that upon reaching the cell membrane, it resulted in a mechanical folding/unfolding motion leading to the nanomachine. to penetrate directly into the cell, destroying the organelles and inducing apoptosis. This new method directly kills cancer cells through mechanical movements without anticancer drugs, in contrast to capsule-like nanocarriers that deliver therapeutic drugs.
Subsequently, a closure molecule was screwed onto the nanomachine to control the mechanical motion to selectively kill cancer cells. The screw cap molecule was designed to be released only in a low pH environment. Therefore, in normal cells with a relatively high pH (approximately 7.4), the movements of the nanomachines were restricted and they could not penetrate the cell. However, in the low pH environment around the cancer cells (approximately 6.8), the zipper molecules became untethered, inducing mechanical movement and cell penetration.
Dr Jeong said: “The developed nanomachine was inspired by proteins that perform biological functions by changing their shape depending on their environment. We propose a new method of direct penetration of cancer cells to kill them through the mechanical movements of molecules attached to drug-free nanomachines. This could be a new alternative to overcome the side effects of existing chemotherapy.”