High Signal to Noise Ratio for Fluorescence Detection with the X-Cite® XLED1

By AZoNano Staff Writers

Table of Content

Limitations of Xenon Lamps
X-Cite XLED1 System
About Lumen Dynamics Group Inc


Susy Kohout, PhD, Department of Molecular Biology, UC Berkeley, USA describes the challenges faced while finding a suitable light source to obtain fluorescence information from Xenopus oocytes while reducing the noise reaching the PMT detector.

Limitations of Xenon Lamps

The lab at UC Berkeley performs experiments on voltage-dependent proteins using tetramethylrhodamine (TMR) maleimide in Xenopus oocytes. With the help of a PMT detector, fluorescence signals are obtained to provide high fluorescence sensitivity for studies.

For fluorescence needs, xenon lamps are often used to connect directly to the microscope, since these lamps deliver a steady light output when measured with a PMT.

However, these light sources have certain limitations and produce plenty of heat, increasing the temperature in the Faraday cage set-up. Another problem is it is difficult to access the lamp housing to replace the lamp and align it within the boundaries of the cage.

Due to these issues, a LED system or light guide lamp provided a better alternative to eliminate the heating up of the Faraday cage. The pre-aligned light source does not need aligning, and the light source can be positioned outside the cage. This greatly helped in reducing the sources of noise and clutter within the cage.

However standard light guide xenon lamp systems produce arc noise, which can be easily detected by the PMT. But manufacturers are unaware of this fact as most users tend to use a camera with these light sources and cameras are not as sensitive as PMT detectors.

Consequently, the UC Berkeley lab switched back to using a xenon lamp housing joined directly to the microscope to obtain the desirable signal-to-noise for the experiment. However, it continued to deal with the inconveniencies of these lamps till it discovered the X-Cite® XLED1 system from Lumen Dynamics.

X-Cite XLED1 System

The X-Cite® XLED1 employs a light guide to bring the light to any microscope and is capable of removing both the excess heating problem and the alignment issue.

The lab was able to utilize the 525nm LED in this four wavelength system to effectively excite the TMR-maleimide.

In addition, the X-Cite® XLED1 delivered a bright and stable light source that complemented and even enhanced the signal to noise.


The X-Cite® XLED1 is a suitable light guide system that produces a bright, stable light source and prevents the excess heat and inconvenience of the xenon lamp housings.

Through this system, the UC Berkeley was able to acquire excellent fluorescence signal without any arc noise associated with the traditional xenon lamp light guide systems. The XLED1 is therefore perfect for live cell fluorescence imaging that requires increased signal to noise and lower heat.

About Lumen Dynamics Group Inc

Lumen Dynamics, an Excelitas Technologies® Company is a global leader in the design and creation of innovative light delivery solutions inspired by close to 30 years of light expertise in Manufacturing and Life Science applications. We are a technology company propelled forward by our commitment to providing customer solutions through the innovative application of light.

Precision bonding and UV curing is at the heart of the company’s manufacturing solutions for electronics/optoelectronics and medical device manufacturing processes, in addition to digital printing; while Life Sciences focuses on illumination and measurement technologies for bioscience research, microscopy and instrumentation. The comprehensive family of Lumen Dynamics’ products includes its renowned brands: OmniCure® and X-Cite®.

This information has been sourced, reviewed and adapted from materials provided by Lumen Dynamics Group Inc.

For more information on this source, please visit Lumen Dynamics Group Inc.

Date Added: Dec 2, 2013 | Updated: Jan 10, 2014
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