Low retention tips are also called binding tips. These pipette tips are modified to minimize the DNA, enzyme, protein, cell adhesion along with other viscous elements to the tip’s surface. The surface of these tips is made out of polypropylene, altered chemically or physically. This alteration reduces the binding and adherence of samples to the plastic surface.
Usage of Low Retention Tips
Sticky or viscous liquids are usually tricky or dispense entirely. Their tendency is to stick to the tip’s surface, affecting the performance of pipetting. Such liquids include plasma, enzymes, foaming liquids, oils, and detergents. Low retention tips come in handy while pipetting detergent-containing solutions, such as PRC master mixes, buffers, and enzyme solutions.
Their surface tension is less compared to water. These solutions do not entirely repel from the tip’s surface. Hence, a liquid film stays after dispensing. As a result, the pipetting accuracy and precision are reduced.
While low retention tips display phenomenal performance, minimum volumes less than 10μl of liquids are not preferred to be pipetted through low retention tips. The inner walls of the tip are very slippery, so the aspirated volumes tend to remain less than targeted or sometimes even impossible to aspirate the liquids altogether.
Manufacturing of Low Retention Tips
Three methods can minimize liquid retention in pipette tips:
- Highly Polished Surfaces
The highly polished surface of the tips molds, such as diamond polished, has a mechanical polishing of the mold. The diamond abrasive makes the tip’s surface significantly smooth and prevents the samples from sticking to it. The age of the mold usually determines the quality of the low retention surface and is variable.
- Plastic Additives
Plastic additives or post-dipping into surface-modifying chemicals are also a remarkable manufacturing means of retention tips. The tips that include additives within the polymer or on the plastic surface are viable to prevent the risk of the chemical compounds from leaching through the tip inside the pipetted solutions. This poses a considerable risk for contamination. Furthermore, the dipping process can often result in uneven coverage of the surface of the tips, thereby reducing the reliability of the pipetting results.
- Complete Hydrophobic Coverage
Innovative proprietary technology allows complete hydrophobic coverage. It is the most advanced method which uses innovative processes to provide the tips with a total hydrophobic coating. Hence, the tips are highly chemically resistant and have a consistent quality.
Difference Between Different Low Retention Tips
All low retention tips are not similar. The composition and performance of low retention tips vary from manufacturer to manufacturer without any commonality. The surface properties and chemical compositions of the low retention tips have a significant variation.
- The Difference in Residual Liquid Amounts
According to statistical data, the results of a test tube from low retention tips of five manufacturers were compared. 200μl of detergents were pipetted through tips of volumes ranging from 200μl, 300μl, and 350μl via an electronic pipette. The quantity of residual liquid that was retained in the tip was measured through a gravimetric analysis. 10 tips from different manufacturers were used to perform the test. The results show that the performance of the tip exhibited a tremendous difference. The outcome varied based on the manufacturer and their manufacturing processes.
- The Difference in Chemical Resistance
This experiment was carried out to determine the difference in chemical resistance. The test results with low retention tips from different manufacturers were chemically treated before measuring the residual liquid amount retained inside the tip. The decreased ability to bind in some tips was decreased through solvent treatment. The results confirmed that low retention tips produced via innovative manufacturing methods could withstand the chemical treatment. This indicates that low retention tips indeed have an inert nature and an adequate chemical tolerance, which has proved to be highly valuable for various experimentation.
The autoclave of low retention tips also varies from manufacturer to manufacturer. At MBP, we have 200μl Low Retention Filter Tips viable for experimentation. These tips comply with all quality standards to deliver the most accurate results.