Detecting single molecules from within cells is crucial both for understanding the basic biology of how a cell functions, but also for developing early diagnostic techniques and possibly even patient-highly specific therapies. Doctors perform biopsies by taking and examining a sample of tissue to evaluate a patient's health. But several diseases at the single cell level may be the result of small changes. Because the cell is a complex system, at very low concentrations, many biological processes occur. In such small quantities, some of the important molecules within a cell exist that they are difficult to detect. Cells are traditionally open to reveal their contents. This destroys the cells, however, and a lot of valuable information is lost, such as the location of molecules in the cell and how cell changes over time.
These miniscule devices are minimally invasive and can pick individual molecules from specific locations within the cell to overcome these challenges researchers have developed a new tool called nano-tweezers. Newly developed "nano-tweezers" can extract single molecules from live cells for the first time without destroying them–solving a long-standing research problem. Retrieving individual molecules from the same cell with absolutely unprecedented spatial resolution and over time would provide a thorough understanding of cellular processes and determine why cells of the same type can be quite different from one another. The research could help scientists build a "human cell atlas," providing new insights into how healthy cells work and what's wrong with diseased ones.
The tweezers are developed from a sharp glass rod that ends with a pair of electrodes made from a material based on carbon similar to graphite. The tip has a diameter of less than 50 nanometers and is divided into two electrodes with a gap between them of 10 to 20 nanometers. By applying an alternating voltage, this small gap creates a powerful localized electrical field that is capable of trapping and extracting small cell contents such as DNA and transcription factors–molecules capable of changing gene activity.
In a population of cells, biological heterogeneity can be embodied by observing a range of phenotypes even if the cell population and environment are nominally homogeneous. This heterogeneity can be caused by dynamical fluctuations in molecular incidents as well as by extrinsic effects, including the nearby cell effects. Biological heterogeneity and the complexities of how heterogeneity occurs in a population can be used to evolve conceptual frameworks to comprehend control mechanisms and anticipate population dynamics and to provide a deeper understanding of intracellular mechanisms, control systems, and mechanisms that assess the progression of a disease.