LEDs enable energy-efficient microscope for fast tuberculosis detection

Nov. 12, 2008
Carl Zeiss has co-developed a rugged, compact LED-excited fluorescence microscope at a low enough running cost to be affordable in poorer countries.
PrimoStar microscope Carl Zeiss, along with FIND, the Foundation for Innovative New Diagnostics, has developed a fluorescence microscope — the Primo Star iLED — that detects tuberculosis in a power- and energy-saving, compact form factor.

Using LEDs instead of mercury lamps, the microscope reduces "the running costs of fluorescence microscopy from more than a dollar an hour to less than half a cent,” said Harald Hoffmann, head of the Institute for Microbiology and Laboratory, Diagnostics, Asklepios Fachkliniken, Munich-Gauting.

With a lifespan of at least 10 years, the LEDs will not likely need to be changed during the microscope’s life time. Other benefits with using LEDs include:
• The microscope is ready to use immediately, without the warm-up and cool-down times required with mercury vapor lamps.
• No danger of being light-dazzled because of reflected-light fluorescence.
• LEDs consume one-tenth the power of a 50 W mercury-vapor lamp.
• Hardly any heat is generated, and samples are protected.

The fluorescence excitation takes place using Auramine O, which is excited by blue LED light with a wavelength of 455 nm and emits from 500 nm to 650 nm. The excitation produces good contrast and signal-to-noise ratio.

The fight against TB
Today, tuberculosis, along with HIV and malaria, tops the statistics of fatal infectious diseases. In view of the development of multi-resistant strains and HIV co-infection, the WHO estimates that tuberculosis will cause 30 million deaths in the next ten years. Today, one in three persons is infected with the tuberculosis bacterium.

Carl Zeiss will supply the product at a particularly favorable price to the public health sector of the 22 high TB-burden countries. According to the World Health Organization (WHO), these countries account for 80% of all global tuberculosis cases.

Fluorescence microscopy is known to be up to 4 times faster than traditional brightfield microscopy for tuberculosis, and published studies are reporting 10% more sensitive detection.

Easy switching between fluorescence and brightfield microscopy makes the microscope suitable for all simple laboratory and routine applications. Thus, other infectious diseases such as malaria can also be detected.

“We are pleased that our collaboration with Carl Zeiss enables us to provide the fluorescence microscope to low resource countries at a favorable price,” says Dr. Giorgio Roscigno, CEO of FIND. Based in Geneva, the Swiss-based Foundation supports the development and introduction of new and affordable diagnostic products to combat infectious diseases in developing countries.

From BioOptics World magazine