The One Drop Method is an alternative sample loading approach for the NanoSight Pro system, designed for situations where sample material is limited. Standard NanoSight Pro measurements typically require samples to be diluted to 10⁶–10⁹ particles/mL (E6–E9 particles/mL) and a minimum volume of 250 μL to support flow-based analysis.
For precious or volume-limited samples, this method enables analysis using as little as 10–20 μL of sample without compromising NTA data quality, provided the sample concentration is appropriate.
The One Drop Method is an alternative sample loading approach for the NanoSight Pro system, designed for situations where sample material is limited. Standard NanoSight Pro measurements typically require samples to be diluted to 10⁶–10⁹ particles/mL (E6–E9 particles/mL) and a minimum volume of 250 μL to support flow-based analysis.
For precious or volume-limited samples, this method enables analysis using as little as 10–20 μL of sample without compromising NTA data quality, provided the sample concentration is appropriate.
With the One Drop Method, a small volume (10–20 μL) of sample at optimal NanoSight Pro concentration is pipetted directly onto the laser module prism. The sample is then sealed using a Low Volume Flow Cell (LVFC) and measured using NS Xplorer software in static mode.
Key features of the method:
This process requires the flow cell to be first removed from the laser module. Unscrew the four sprung securing screws and remove the flow cell. Use compressed air at a safe 15 cm distance to clean and dry the optical surface. This ensures there is no dust or particulates that could contaminate your sample and influence the measurement.
1. Prepare the sample at an optimal concentration for NanoSight Pro NTA: E6–E9 particles/mL.
2. Load a calibrated pipette with 10-20 μL of sample.
3. Pipette the sample directly onto the laser module prism in the position shown in the figure. Ensure the droplet forms a stable bead and does not spread prematurely.
![[Figure 1.1 TN260814-nanosight-pro-one-drop-method.png] Figure 1.1 TN260814-nanosight-pro-one-drop-method.png](https://dam.malvernpanalytical.com/347b828b-c3ae-42f0-a68f-b4e300eaf1cc/Figure%201.1%20TN260814-nanosight-pro-one-drop-method_Original%20file.png)
Figure 1.1 Sample drop on laser prism
4. Carefully position the flow cell over the prism and lower it vertically into position. Insert the four sprung securing screws. Tighten the screws two at a time in a diagonal sequence. Press down the screw as you tighten to compress the spring. As the flow cell is tightened, it spreads the sample to cover the prism and scatter area.
![[Figure 1.2 TN260814-nanosight-pro-one-drop-method.png] Figure 1.2 TN260814-nanosight-pro-one-drop-method.png](https://dam.malvernpanalytical.com/3d43a765-ce6b-4e57-8b26-b4e300ead367/Figure%201.2%20TN260814-nanosight-pro-one-drop-method_Original%20file.png)
Figure 1.2 Sample drop spread over prism and scatter area
5. Verify that the flow cell is fully assembled and stable.
6. Insert the laser module into the NanoSight Pro.
1. Launch NS Xplorer and start the camera.
2. Confirm that particles are visible and that the image quality is comparable to standard NTA measurements.
![[Figure 1.3 TN260814-nanosight-pro-one-drop-method.png] Figure 1.3 TN260814-nanosight-pro-one-drop-method.png](https://dam.malvernpanalytical.com/3f94d0ec-80be-470e-8d62-b4e300ead2e7/Figure%201.3%20TN260814-nanosight-pro-one-drop-method_Original%20file.png)
Figure 1.3 Check image quality
3. Do a light scatter measurement. As no fluidics are connected, set the Flow control to Static and Advance Sample to Off.
![[Figure 1.4 TN260814-nanosight-pro-one-drop-method.png] Figure 1.4 TN260814-nanosight-pro-one-drop-method.png](https://dam.malvernpanalytical.com/164fa743-286b-4b87-8898-b4e300eaf476/Figure%201.4%20TN260814-nanosight-pro-one-drop-method_Original%20file.png)
Figure 1.4 Measurement conditions for one drop method
4. Analyze the results and assess the data quality.
After the measurement, remove the flow cell from the laser module. Gently wipe the optical surface of the laser module with a water-wetted tissue. Dry with a soft dry tissue followed by compressed air.
Using a wash bottle, apply a small amount of particle-free water to the LVFC surface that was in contact with the sample to remove any residue. Dry using compressed air from a safe 15 cm distance.