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1. UV-Star^/sup> microplates withUV-transparent bottom

Applications:
reading of DNA and totalprotein at 260 nm or 280 nm

Advantages:
extended optical UV-window
low background
superior overall performance

2. lear^/sup> microplates high clarityfilm as bottom, optimized blackand white pigmented resins

Applications:
Luminescence
Fluorescence
Cell monitoring
Transmission
Imaging

Advantages:
low background
low crosstalk
low autofluorescence

The microplate format was commercially introduced in the mid 1960 as a handy and miniature replacement of high volume test tubes. At that time, no one expected that this plate would serve as a reliable format in screening applications. Based on the well-established 96 well microplate, a new era of highthroughput screening for miniaturized assays started in 1994/95 with the launch of 384 well microplates.

The 384 well microplate quadruples the well density with awell to well spacing of 4.5 mm and a total volume slightly morethan 120 . The design of the microplate complies with the96 well footprint and the SBS-recommendations.

The on-going demand to further reduce cost per assay and limitations in the availability of reagents and test material turned the direction to even higher density microplates. To utilize space most efficiently, we focused on a high density microplate with 1536 wells, another 4-fold increase over the 384 well microplate. The center of a group of sixteen wells is unchanged at 9.0 mm and a well to well pitch of 2.25 mm. The introduction of this high density microplate fulfills the requirements in fully automated systems formats for High- Throughput Screening (HTS). Initially mostly solid white opaque and black pigmented microplates were requested. With the move from isotopic to non-isotopic assays (fluorescence, luminescence and colorimetric) and new applications in all culture there has been a demand for clear bottom microplates as well.

Conventionally, clear bottom microplates have been manufacturedby either 2-component injection molding or theassembling of two individual parts by ultrasonic welding orglue. The development of a completely new molding andprocess technology enabled the manufacture of uniqueclear bottom microplates with ultra-thin films (50 500 ).The process in use is absolutely free of any kind of solventsand avoids leakage from the wells. Additionally, a newproprietary resin and modifications on the process technologyexpanded the optical window in the UV-range down to 200 nm.The new UV-Star^{/sup> microplates are advantageous when DNAandprotein samples are investigated at 260 nm or 280 nm.}

Black and white opaque microplates
White opaque microplates are commonly used in luminescenceapplications (e. g. luciferase reporter assay)while black pigmented plates are preferred in fluorescenceassays (e. g. Green Fluorescence protein).

The optical and physical properties of UV-Star^{/sup> and lear/sup>microplates have been investigated in our labs on a BMGFluoStar or TECAN SpectraFluor Plus, respectively. It wasclearly demonstrated that the amount of pigment in the parentresin has a major impact on the performance of the microplates.This effect was seen more clearly at lower excitation andemission wavelengths and resulted in a tremendous increaseof autofluorescence compared to the fluorescein wavelengths 485/520 nm (Fig. 1 and 2). A similar effect has beenobserved in white opaque microplates when examiningphosphorescence in different sets of pigmented resins.}

lear^{/sup> and UV-Star/sup> microplates}
In the near and far UV-range transmission of lear^{/sup> andUV-Star/sup> microplates have advantages versus conventionalmicroplates (Figure 3).}

μClearplates have an extended wavelength range and gain more sensitivity due to a reduced background.

Measurements, e. g. NADH and NADPH at 340 nm becomemore critical as they are directed with a significantdecrease in transmittance when read in conventional plates.The span from 400 to 600 nm and above is not effected intransmittance between a lear^{/sup> and the new UV-Star/sup>microplate (Figure 3).}

UV-Starmicroplates for DNA and Proteins
For measurements of protein and DNA concentrations(Figure 4 and Figure 6) at 260 nm and 280 nm respectively, themost advanced UV-Star^{/sup> microplates are highly recommended.For applications in Genomics and HTS there was a strongdemand for higher density plates, UV-Star/sup> microplates witha 384 well format. The background is less than 0.060 E at260 nm (Figure 4) with excellent homogeneity of the plate(Figure 5), similar to 96 well plates.}

To cross-reference 384 well and 96 well UV-Star^{/sup> microplatesin DNA-applications the liniearity was evaluated at multipleconcentrations at 260 nm (Figure 6). With the availabillity of disposableUV-transparent microplates there is no further need forexpensive fragile quartz glass plates in routine laboratory work.}

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