Electrophoresis is among the most heavily relied upon life science techniques, supporting a broad range of research and analytical testing applications including sequencing, drug discovery, pharmacotoxicology and forensics. Using this technique, fragments of DNA, RNA or proteins are separated on the basis of size and charge, typically using a matrix of agarose gel for larger nucleic acid fragments, or polyacrylamide gel for smaller fragments and protein. Following separation, the molecules can be imaged for analysis, and/or extracted from the gel for downstream applications. To improve safety and reduce damage to DNA samples, blue light transilluminators are gaining market momentum for the visualization and documentation of electrophoresis gels.

DNA and RNA are not visible without the aid of staining. A dye is typically included in the loading buffer that is mixed with the sample to be resolved; alternatively, the entire gel can be treated following the electrophoresis run. By far, the most commonly used dye for visualizing DNA/RNA bands is ethidium bromide (EtBr), which binds to nucleic acids and fluoresces under UV light. However, EtBr is highly toxic and mutagenic, posing risks to users and requiring hazardous waste disposal for anything that comes into contact with it, such as gloves and pipette tips.

The UV light source required to excite EtBr is very intense, and users must wear personal protective equipment to avoid exposure, such as glasses, face shields and clothing to protect from sunburn. The use of EtBr and UV has been shown to damage DNA samples, affecting downstream applications. Even 30 seconds of UV exposure is enough to drastically reduce cloning efficiency.

Blue light transilluminators offer a safer alternative for gel viewing. They emit light in the range of ~465 nm, which poses relatively little risk to users, though eye protection is still recommended. In contrast, UV gel viewers utilize 302 nm or 356 nm wavelengths, which are hazardous to users and may cause crosslink and photonicking damage to DNA samples. Many vendors produce nucleic acid and protein stains that are excitable by blue light transilluminators and are considered safer than EtBr.

The greatest hurdle to wide adoption of blue light transilluminators is the cost of stains, which are far more expensive than EtBr. The cost of staining a 100 mL gel with EtBr is fractions of a penny, while the cost of staining that gel with SYBR Safe, a less mutagenic stain manufactured by Invitrogen (Thermo Fisher Scientific), is in the range of $0.70–$1.00. Some alternative stains are also less sensitive than EtBr.

There is a growing number of suppliers providing blue light transilluminators. The market leader for dedicated blue light transilluminators is Thermo Fisher, which offers the Safe Imager 2.0. Other leaders in the general electrophoresis imaging market, such as Bio-Rad Laboratories and GE Healthcare, offer blue light filters, which convert their existing UV-based gel documentation units to wavelengths in the blue light range.

Most models on the market are standalone viewers, but some are available with integrated imaging hoods. Transilluminators are produced in a range of sizes, as the typical size of a gel varies depending on application. The total market demand for blue light transilluminators was estimated at $13 million in 2017.

Blue Light Transilluminators at a Glance

 Leading Vendors:

• Thermo Fisher Scientific
• VWR
• Analytik Jena (Endress+Hauser)

Largest Markets:

• Academia
• Biotechnology
• Government

Instrument Cost:

• $400–$1,300