Breakthrough method could provide pathologists with a less expensive alternative to high-priced super-resolution microscopes or often-imprecise microscopy software
Intriguing new research has the potential to “turbocharge” the standard medical laboratory microscope in ways that create a “super-vision” capability. This would give pathologists and medical researchers an inexpensive alternative to high-priced super-resolution microscopes or often-imprecise microscopy software.
Seeking a new method for counting molecules in complexes, researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University paired their DNA-powered super-resolution microscopy platform—DNA-PAINT and Exchange-PAINT—with a new procedure called quantitative points accumulation in nanoscale topography—or qPAINT. This new analytic tool can “count different molecular species in biological samples with high accuracy and precision,” noted a Wyss Institute press release.
In the March 28, 2016, issue of Nature Methods, Peng Yin, PhD, Core Faculty Member at the Wyss Institute and senior author of the study, stated in a Wyss news release, “qPAINT, as we named it, can accurately count the actual numbers of specific molecules at specific locations inside the cell.
“Introducing this quantitative power has crucially extended the spectrum of imaging capabilities of this comprehensive and inexpensive technology, so that it can be applied in many areas of biological and clinical research,” Yin concluded.
Identifying Points of Light
The DNA-driven technology allows researchers to quantify the number of molecules at specific locations in the cell without the need to spatially resolve them. It does this by directing the transient interaction of two short strands of DNA:
• one called the “docking strand,” which is attached to the molecular target to be visualized; and
• the other called the “imager strand,” which carries a light-emitting dye, the Wyss Institute press release explained.
“qPAINT allows identification of each point of light coming from a labeled molecule without the need for complex and sometimes inexact microscopy calculations,” Behrouz Shabestari, PhD, Program Director for Optical Imaging and Spectroscopy at the National Institute of Biomedical Imaging Bioengineering (NIBIB), stated in a press release. “The method overcomes the problem that occurs when trying to visualize molecular structures that are in very close proximity: light diffuses as it leaves the spot where it originates. This masks exactly how many points of light—each representing a single molecule—are actually creating the light.”
As noted in ScienceDaily, “Knowing the exact number of molecules located at specific junctures in cells can be a critical measure of health as well as disease. For example, abnormally high numbers of growth factor receptors on cells can be an indication of cancerous and precancerous states; specific proteins located at the junction where neurons connect in the brain may affect brain function as they accumulate or disperse.”
Super-Resolution on Standard Clinical Lab Microscopes
Yin and his team have focused on providing life sciences researchers with ways to achieve sub diffraction-imaging resolution using standard fluorescent microscopes.
“Few laboratories can afford these expensive [super-resolution] microscopes,” Yin stated in the NIBIB press release. “Our qPAINT technology reveals the same precise information using microscopes that are 10 times less expensive and are already standard equipment in most laboratories. qPAINT can also detect these targets at deeper depths in tissues than is capable with the very expensive microscopes. It is also much simpler and more precise than other software-based methods that are currently used with less expensive microscopes.”
Ultivue Inc., a company spun out from Harvard University, is commercializing the imaging reagent technology developed at the Wyss Institute. qPAINT will be made commercially available through Ultivue, which also is developing a more economical microscope than is currently available to work with qPAINT, the NIBIB release stated.
“We see qPAINT and Ultivue as agents for research democratization,” Yin said in the NIBIB statement, referring to the company’s ability to provider researchers with affordable alternatives to expensive research tools.
The fact that qPAINT uses a standard microscope to perform more sophisticated procedures involving fluorescent markers makes this advancement of great interest to pathologists and clinical laboratory managers. Further development of this technology could result in a product that could be used in clinical diagnosis, providing anatomic pathologists with a less expensive way to perform more sophisticated diagnostic testing within their group practices.
—Andrea Downing Peck