Nanostraws Collect Samples From Cells Without Causing Damage
Novel technology, which takes inspiration from a cell’s biological transport mechanism, can collect samples of cellular material without rupturing the membrane and killing the cell. Originally designed to deliver molecules into cells, researchers have demonstrated that “nanostraws” can extract molecules and genetic material from inside the cells —an advance that could lead to better understanding of cell development, chemotherapy resistance, and the discovery of more effective therapies.
Nicholas Melosh, an associate professor of materials science and engineering at Stanford University, was first inspired to develop nanostraw technology in 2012 while studying cellular gap junctions, which are pathways between cells that transport nutrients and other molecules. Nanostraws are hollow, metal-oxide nanotubes 600 times smaller than a human hair, small enough to penetrate the cell’s membrane without causing it to rupture.
Over the last five years, Melosh and his team have developed several potential applications, primarily related to drug delivery. In a study published in 2016, researchers demonstrated the effectiveness of nanostraws in delivering second messengers in cell signaling pathways, opening possibilities for timed-release drug delivery.
Recent research has explored the possibility that the nanostraw system could work in reverse, withdrawing instead of adding material to the cell. The traditional method of collecting cellular material, called lysing, penetrates the cell’s membrane and causes it to rupture. Though researchers can use the method to collect samples from inside cells, the process kills the cells, making it impossible to further study the development of the same cell over time.
Melosh explained that the ability to sample a cell more than once, over time, would help facilitate a better understanding of cell development. In a paper published in Proceedings of the National Academy of Sciences of the United States of America (PNAS), Melosh and his team demonstrated that the Nanostraw Extraction (NEX) system could extract samples 90 percent congruous with samples collected using lysing.
“What we hope to do, using this technology, is to watch as these cells change over time and be able to infer how different environmental conditions and ‘chemical cocktails’ influence their development — to help optimize the therapy process,” Melosh told Stanford News.
Graduate student and first author of the study Yuhong Cao explained that the NEX system could help researchers better understand the ability of stem cells to develop into other varieties of cells, or why some cells are resistant chemotherapy while others are not.
“With chemotherapy, there are always cells that are resistant,” said Cao. “If we can follow the intercellular mechanism of the surviving cells, we can know, genetically, its response to the drug.”
Melosh said that his goal is to make the technology available to as many researchers as possible in a platform that any lab could potentially build.
“It’s a super exciting time for nanotechnology,” said Melosh. “We’re really getting to a scale where what we can make controllably is the same size as biological systems.”
Scientists in the UK have developed tiny nanoneedles that can inject nucleic acids into cells in a way that greatly reduces the risk of cell damage or death. Researchers said that the technology could be used to help the body repair itself or to reduce the chance of organ transplant rejection.