The NanoDrop ND-1000 (NanoDrop Technologies) is a full-spectrum (220-750nm) spectrophotometer that can measure 1 ul samples with high accuracy and reproducibility. The spectrophotometer utilizes a patented sample retention technology that employs surface tension alone to hold the sample in place. This eliminates the need for cumbersome cuvettes and other sample containment devices and allows for clean up within seconds.
The ND-1000 has the capability to measure highly concentrated samples without dilution (50x higher concentrations than samples measured by a standard cuvette spectrophotometer). It can detect between 2 and 3700 ng/ul for dsDNA; 2-3000 ng/ul RNA and 2-2400ng/ul ssDNA, without dilution of samples. For microarray analysis, it can very precisely detect the fluorescent dye-labeling density of nucleic acid samples: 0.2-100 pmols/ul for Cy3 and 0.2-60 pmols/ul for Cy5. Also, the ND-1000 spectrophotometer will accurately measure protein samples up to 100 mg/ml (BSA) without dilution.
The spectrophotometer ND-1000 is used in our department for measuring the concentration and purity of nucleic acids samples (DNA and RNA). For us, it is very important to precisely determine the concentration of DNA or RNA which will be used for real-time PCR and microarray analysis. The ND-1000 is very useful when you have just a few ul of sample (e.g. following nucleic acids extraction with a micro kit). I have worked on some microarray projects where I had to make the extraction of RNA with micro kit (Qiagen); because the RNA elution was made in 16 ul, it was very important to find a method for evaluating the RNA for quality and quantity using just a few ul of sample. The rest of material was very important for generating the microarray samples (cRNA labeled with Cy-3 and Cy5). For microarray, it’s very important to verify the concentration of the probes in all the steps: RNA extraction, cDNA synthesis, cRNA-Cy3 (Cy5) generation. I made all the measurements in duplicate and the results were reproducible. Sometimes I did obtain differences between replicates. I verified the column of liquid (i.e. sample) between the upper and lower measurement pedestals and I saw that there was no the column. In these conditions I increased the volume for analysis to 1.2 ul and then all was ok.
For using this spectrophotometer, you need a PC and a print out. The software for the ND-1000 is very complex, but friendly. Compared to the competition, it’s the best. The results are very reproducible and there is no need for cumbersome cuvettes or other sample containment devices. In conclusion, this equipment is very useful for all departments of molecular biology and especially for microarray analysis.