Fluorescence spectroscopy is useful for the analysis of a broad range of organic compounds. A subset of fluorescence spectroscopy is lifetime fluorescence, which offers advantages compared with conventional steady-state fluorescence. Although there are less than half a dozen significant competitors in the market, the strong growth forecast for lifetime fluorescence offers potential for new market entrants.

Lifetime fluorescence measures the time between excitation and relaxation of fluorophores, rather than just the intensity of the emitted energy, and can be measured using either time domain or frequency domain techniques. Time domain lifetime fluorescence measures the time it takes for molecules to fluoresce after being excited by a light source, and most often is applied using time-correlated single photon counting (TCSPC). Another version of lifetime fluorescence is frequency domain lifetime fluorescence, which compares the modulation and phase shift of the emitted energy relative to the excitation energy.

While both versions of lifetime fluorescence yield comparable data, frequency domain lifetime fluorescence typically offers higher signal-to-noise and has a faster analysis time, which makes it better for real-time sensing. A variation of lifetime fluorescence spectroscopy is fluorescence lifetime imaging microscopy (FLIM), which is used for examining biological tissues.

Lifetime fluorescence offers more information, is more sensitive and provides higher resolution than conventional steady-state fluorescence spectroscopy. It was not until the 1990s that lasers and electronics advanced to the point that vendors could produce reasonably priced and simple-to-operate lifetime instruments that reduced analysis times from minutes, or even hours, to seconds.

Lifetime fluorescence is most popular in the biotech industry, because fluorescent compounds can be used as chemical tags. Likewise, fluorescent dyes can be used in tandem with FLIM in the biomedical and clinical areas. Applications in the biotech and related areas include studying protein folding and monitoring enzyme reactions. There are limited applications in areas such as electronics for developing LEDs, plastics for characterizing polymers, and oil and environmental labs for the characterization of crude oil.

Horiba has built up a strong leading position in the lifetime fluorescence market through its acquisitions of Jobin Yvon (see IBO 9/30/97), including its SPEX product line, and the purchase of IBH (see IBO 9/30/03). ISS is a small company that specializes in lifetime fluorescence. Horiba and ISS are the two main vendors of frequency domain lifetime fluorescence instruments. Each company also supplies TCSPC systems. Other competitors in the lifetime fluorescence market include Edinburgh Instruments, PicoQuant GmbH and Photon Technology International. The total market was about $22 million in 2009, and is expected to grow in the high double digits.

Lifetime Fluorescence at a Glance:

Leading Suppliers

• Horiba

• ISS

• Edinburgh Instruments

Largest Markets

• Biotechnology

• Academia

• Hospital/Clinical

Instrument Cost

• $15,000–$80,000