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Rethinking Fluorescence Microscopy

Rethinking Fluorescence Microscopy

The light source of a fluorescence microscope often goes unnoticed, but LED illumination offers a win-win for sustainability and performance

Isabel Goodhand

After completing a PhD in molecular biology at the University of Portsmouth, UK, Isabel moved into scientific communication where she has more than 10 years of experience. As Technical Content...

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Laboratories are notoriously resource-intensive, but a trend is growing across academia, industry, and government to reduce their environmental impact. For example, the UK Research and Innovation (UKRI) Environmental Sustainability Strategy details a plan to consider environmental sustainability as part of funding decisions, and grant and training terms1. Many universities and companies across the pharmaceutical and biotechnology sectors now have sustainability officers to reduce environmental impact, and environmentally friendly technology is becoming increasingly available.

One such piece of laboratory equipment is the fluorescence microscope. Although a familiar sight in many life science laboratories, the light source can easily be overlooked. Many microscopes still use energy-hungry, toxic mercury or metal halide lamps, but modern LED technology now offers a cleaner, more efficient, and high-performance alternative.   

Why are labs switching to LED illumination?

Compared to traditional mercury-based illumination such as metal halide lamps, the reduced environmental impact of LED illumination systems is largely the result of two factors: saving energy and avoiding mercury. One independent comparison of an LED illumination system and a traditional mercury lamp found that the mercury lamp consumed more than 10 times more energy over 25,000 hours of use2.

These numbers might seem surprising, but this takes into account the warm-up time required before a lamp can be used, and a cool down period before they can be safely used again. LED illuminators for microscopes instead switch on or off instantly, and need to draw power only when illumination is required. Many laboratories leave their mercury-based lamps switched on all day to ensure availability when required, yet LED illumination systems can be powered up quickly. This improved energy efficiency also comes with a potential cost saving of $41,0002.

 Although many laboratories do not pay directly for energy consumption, the wider organization can financially benefit. For this reason, it is worth contacting your facilities department and inquiring about financial support for energy-efficient equipment, which are sometimes known as “Green Grants.”

“Many microscopes still use energy-hungry, toxic mercury or metal halide lamps, but modern LED technology now offers a cleaner, more efficient, and high-performance alternative.”

Traditional lamps contain mercury, which is notoriously toxic and gradually accumulates in tissue as it passes through the food chain, damaging wildlife populations. Due to its harm to people and the environment, the use and disposal of mercury is subject to legislation in many countries. Cost savings are also a factor here, since disposing of old mercury lamps has a financial impact over time. It is worth considering that countries are moving toward banning mercury lamps. The Minamata Convention, which is an agreement to address widespread mercury pollution, has now been adopted by 131 countries, and there is increasing pressure from the United Nations to ban mercury-based lamps, since a viable alternative now exists in the form of LEDs3. For laboratories with several microscopes, planning ahead with a phased introduction of LED illumination is recommended in advance of a future ban.

In addition to sustainability and long-term cost savings, there are many performance benefits to LED illumination, including:

  • Electronic control enables imaging at speeds of under 7 µs, improving the temporal resolution of live cell imaging experiments. 
  • Discrete LED channels can often be selected individually to match the fluorophore set in use, improving image contrast. 
  • Intensity modulation from zero to 100 percent makes it easy to optimize illumination without neutral density filters, reducing phototoxicity and photobleaching for better results and longer time-lapse studies.  
  • Many LED illumination systems can be controlled directly from third-party imaging software, making it simple to configure optimized illumination settings.  
  • Illumination is stable over time.
  • No need for alignment as with lamps. 

Making sustainable decisions

Even as sustainable laboratory equipment such as LED illumination systems become more widespread, it can be challenging to know how to make the best purchasing decision. To help make sustainable purchasing choices, the not-for-profit organization My Green Lab developed The ACT Label. ACT stands for accountability, consistency, and transparency, and is like an “eco-nutrition label” for lab products. Each label provides a score that reflects the complete environmental impact of manufacturing, using, and disposing of a product and its packaging (Figure 1).

Figure 1: Inside the ACT Label. An example of an ACT Labels and how scores can improve over time. Following independent auditing from My Green Lab, the final score is calculated from categories relating to the manufacturing, shipping, using and disposing of a product and its packaging. The majority of categories are rated from 1-10, where the lower score means lower environmental impact. 

By having a score, this also helps suppliers focus on ways to reduce their impact even further and become increasingly sustainable. Initiatives such as the ACT Label reach further than a single product and establish an actionable approach to empower suppliers and scientists alike to “walk the walk” of sustainability.

Labs are increasingly looking to replace their traditional fluorescence microscope lamps with LED illumination systems due to both performance and sustainability benefits—and each upgrade brings the science community closer to a cleaner, “greener” future. 


  1. UK Research and Innovation (2020). UKRI Environmental Sustainability Strategy. Available at: (downloaded 28 April 2021)
  2. Green Light Laboratories (2017). mercury versus LED study. Available at: (downloaded 28 April 2021)
  3. United Nations Environmental Programme (2017). Minamata Convention on Mercury.

For additional resources on fluorescence microscopy, including useful articles and a list of manufacturers, visit