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Researchers have created artificial cells-like structures from inorganic matter, which can autonomously ingest and process material, thereby regenerating an essential function for living cells.
Their Nature article provides a blueprint to create "cell mimics" with potential applications in drug delivery and environmental science.
Living cells have a fundamental function: they can harvest energy from the surrounding environment to pump molecules into and out of their systems. Active transport is the use of energy to move molecules from lower concentration areas to higher concentration areas. Cells can use active transport to absorb necessary molecules such as glucose and amino acids, store energy and extract waste.
Researchers have worked for decades to engineer artificial cells that mimic the behavior and features of living cells. These cell mimics are not able to perform complex cellular processes such as active transport.
Researchers from New York University and Chicago have described a fully synthetic cell mimic in the Nature study. This mimic is one step closer at replicating the functions of living cells. The cell mimics can autonomously capture, concentrate, store, and deliver microscopic cargo when they are deployed in mixtures. These artificial cells can be made with minimal ingredients and do not borrow from biology.
Video microscopy shows artificial cells mimicking foreign particle ingesting, holding, and expulsion. Credit: Sacanna Lab, NYU
Researchers created a spherical cell mimic using a polymer. This is a substitute for the cell membrane, which controls what goes inside and out of cells. The researchers made a tiny hole in the spherical membrane to create a nano-channel that allows matter to flow through it, mimicking a cell's protein channels.
However, active transport requires a mechanism that can power the cell's cell-like structure to pull in material and expel it. Active transport is a function of ATP and mitochondria in a living cell. Researchers added a chemically reactive element to the nano-channel, which when activated by light acts as a pump. The pump triggers a chemical reaction when light strikes it. This turns the pump into a tiny vacuum that pulls cargo into the membrane. The pump can be switched off to trap the cargo and allow it to be processed within the cell mimic. The chemical reaction can be reversed and the cargo can be pushed out when it is needed.
Stefano Sacanna is an associate professor of chemistry at NYU. He was the study's principal author. The cell-like structure's core is built around the interaction between an active component that powers it from within and the physical limitations imposed by cell walls. This allows them to inhale, process, and expel foreign body.
Researchers tested cell mimics in various environments. One experiment involved suspending the cell mimics in water and activating them with light. They observed that they ingested particles and impurities from the surrounding water. This suggests a possible application for cleaning water of microscopic pollutants.
Video microscopy shows artificial cells mimicking the ingesting of E.coli bacteria. Credit: Sacanna Lab/NYU
Sacanna said, "Think about the cell mimics as the PAC-MAN videogamethey go around eating pollutants and removing them form the environment."
Another experiment showed that cell mimics could swallow E.coli bacteria and trap it inside the membrane. This could potentially be a new way to fight bacteria in the body. The cell mimics can also release a preloaded substance if activated, which could lead to drug delivery.
Researchers continue to study cell mimics and build new ones. They also learn how cells communicate with one another.
Further information on the Transport pathway for cell waste, which is important for future treatment of cancer and dementia
More information: Transmembrane Transport in Inorganic Colloidal Cell Mimics, Nature (2021). www.nature.com/articles/s41586-021-03774-y Journal information: Nature Transmembrane transport in inorganic colloidal cell mimics,(2021). DOI: 10.1038/s41586-021-03774-y