Can ultrafiltration centrifuge tubes be reused?  Here’s the answer

A centrifuge tube is a simple tube that can withstand high rotational speed and pressure, such as separating some samples and separating supernatant sediments. The ultrafiltration centrifuge tube has two parts similar to the inner tube and the outer tube. The inner tube is a membrane with a certain molecular weight. During high-speed centrifugation, those with a smaller molecular weight will leak into the lower tube (i.e. the outer tube), and those with a larger molecular weight will be trapped in the upper tube (i.e. the inner tube). This is the principle of ultrafiltration and is often used to concentrate samples.

Ultrafiltration centrifuge tubes usually can be used without pretreatment, but for protein sample processing, especially for dilute protein solutions (< 10ug / ml), the recovery rate of concentration with ultrafiltration membranes is often not quantitative. Although PES materials minimize nonspecific adsorption, some proteins, especially when they are dilute, may have problems. The degree of nonspecific binding varies with the structure of individual proteins. Proteins containing charged or hydrophobic domains are more likely to bind irreversibly to different surfaces. Passivation pretreatment on the surface of the ultrafiltration centrifuge tube can reduce the loss of protein adsorption on the membrane surface. In most cases, pretreatment of the column before concentrating the dilute protein solution can improve the recovery rate, because the solution can fill the blank protein adsorption sites exposed on the membrane and surface. The passivation method is to pre soak the column with a higher volume of passivation solution for more than 1 hour, wash the column thoroughly with distilled water, and then centrifuge it once with distilled water to completely remove the passivation solution that may remain on the film. Be careful not to let the film dry after passivation. If you want to use it later, you need to add sterile distilled water to keep the film moist.

Ultrafiltration centrifuge tubes cannot usually be sterilized and reused. Since the price of a single tube is not cheap, many people try to reuse it – the experience is to clean the membrane surface with distilled water for many times and centrifuge it once or twice. The small tube that can be centrifuged in reverse can be immersed in distilled water and then centrifuged in reverse for more times, which will be better. It can be used for the same sample repeatedly, and can be soaked in distilled water when not in use, but bacterial contamination shall be prevented. Do not mix different samples. Some people say that soaking in 20% alcohol and 1n NaOH (sodium hydroxide) can prevent the growth of bacteria and prevent drying. As long as the ultrafiltration membrane invades water, it can not be allowed to dry. However, others say that it will destroy the membrane structure. In any case, manufacturers generally do not support reuse. Repeated use will block the pore size of the filter membrane, and even cause liquid leakage, which will affect the experimental results.