New imaging technique to analyze microscopic samples more accurately

Scientists from Curtin University have identified a new method to analyze tiny samples more precisely. With the help of chemically luminescent molecules, the researchers have now made such microscopic samples to “glow in the dark.”

Controlling chemiluminescence in two dimensions. Image Credit: Dr Yan Vogel.

According to Yan Vogel, a lead researcher from the School of Molecular and Life Sciences, present-day techniques of microscopic imaging depend on fluorescence, which means the specimen has to be illuminated by light while it is being studied. Although this is an effective method, it also has certain disadvantages.

Most biological cells and chemicals generally do not like exposure to light because it can destroy things—similar to how certain plastics lose their colors after prolonged sun exposure, or how our skin can get sunburnt.”

Dr Yan Vogel, Lead Researcher, School of Molecular and Life Sciences, Curtin University

Dr Vogel continued, “The light that shines on the samples is often too damaging for the living specimens and can be too invasive, interfering with the biochemical process and potentially limiting the study and scientists’ understanding of the living organisms.”

Noting this, we set out to find a different way to analyze samples, to see if the process could successfully be completed without using any external lights shining on the sample.”

Dr Yan Vogel, Lead Researcher, School of Molecular and Life Sciences, Curtin University

The researchers effectively identified a method to apply chemical stimuli to essentially make user-defined regions of the samples “glow in the dark,” thus making it possible to examine these regions without the need for any potentially damaging external light.

Dr Simone Ciampi, the study’s co-author and ARC Future Fellow from Curtin University, stated that until now, activating a dye with chemical stimuli, rather than using high energy light, was not technically feasible.

Before discovering our new method, two-dimensional control of chemical energy conversion into light energy was an unmet challenge, mainly due to technical limitations. There are few tools available that allow scientists to trigger transient chemical changes at a specific microscopic site.”

Dr Simone Ciampi, Study Co-Author and ARC Future Fellow, Curtin University

Dr Ciampi continued, “Of the tools that are available, such as photoacids and photolabile protecting groups, direct light input or physical probes are needed to activate them, which are intrusive to the specimen. Our new method however, only uses external light shining on the back of an electrode to generate localized and microscopic oxidative hot-spots on the opposite side of the electrode.”

“Basically, the light shines on an opaque substrate, while the other side of the sample in contact with the specimen does not have any exposure to the external light at all. The brief light exposure activates the chemicals and makes the sample ‘glow in the dark’,” Ciampi further stated.

“This ultimately addresses two of the major drawbacks of the fluorescence method – namely the interference of the light potentially over-exciting the samples, and the risk of damaging light-sensitive specimens,” Dr Ciampi concluded.