What is the difference between flocking swabs, sponge swabs and ordinary cotton swabs?

What is the difference between flocking swabs, sponge swabs and ordinary cotton swabs?

In fact, the cotton swabs that everyone is talking about is actually not accurate. The professional term is called 'swabs', which are mainly divided into three categories: ① flocking swabs, ② sponge swabs and ③ cotton swab swabs.

And swabs are not available because of the new crown epidemic. Microbiological sampling is involved in many fields such as food, medical care, and catering, so as to control and manage public health. For example, the 'National Food Safety Standard for Disinfection of Dining (Drinking) Utensils' GB14934-2016 stipulates that Salmonella typhi, Escherichia coli, and Staphylococcus aureus are the main detection bacteria for tableware and drinking utensils. Sampling will use swabs, which are used to collect microorganisms on the surface of the object to be tested.

Next, let's take a look at the structure of the three types of swabs commonly used in clinical practice, and what are the characteristics of each.

Flocked swab

The flocking swab is mainly composed of nylon short fiber fluff head and ABS plastic rod, which is a kind of disposable sampling swab. The head of the flocking swab is a neat nylon short fiber bundle with a regular structure and a brush-like structure, with each nylon fiber perpendicular to the base.

Flocked swab head structure (overall)

The special structure of the flocked swab head can make the entire sample collection area without internal absorption holes, and the capillary action between nylon fiber bundles promotes strong hydraulic absorption of liquid samples, and its adsorption force is very strong in collecting viruses and DNA. ; The collected sample remains on the surface of the fiber bundle, will not disperse and stay in the fiber, which makes the elution easier and also has a better release rate.

The flocked swab head has a large contact area and a long handle. Its fast adsorption capacity and excellent release efficiency provide protection for limited or trace amounts of DNA, and it is especially suitable for the extraction of exfoliated cells on outdoor sites and in contact.

sponge swab

Sponge swabs are made of layers of mesh cotton and are often used to moisturise the mouth and help loosen thick mucus secretions, food scraps and thickened saliva, and are also commonly used in eye surgery.

The structure of the sponge swab head is a mesh structure, and it is difficult for microorganisms to be released after entering the inner mesh.

cotton swab

Traditional cotton swabs are made of thousands of meters of fibers wrapped around the top of a plastic rod. It is an important equipment for collecting biological evidence. It is suitable for the sampling of mucous membranes and wounds, and is often used to extract biological samples.

The swabs created a matrix environment with many gaps in the arrangement. Cells and microorganisms that have been collected after sample collection are trapped in these crevices, trapped in the fibrous matrix of the head, and difficult to be released.

Therefore, when testing the nucleic acid of the new coronavirus, we usually use the first one - the flocking swab.

Are flocked swabs toxic?

The so-called flocking swab, the part that comes into contact with the human body is mainly its head, and the material is nylon fiber. In our country's standard 'Collection and Transfer of Clinical Microbiological Test Samples' WS/T 640-2018 clearly stipulates that the material of the sampling swab head is synthetic polyester fiber, polyamide fiber, rayon and foamed polyurethane, etc. Fluorescent agents do not appear.

In the production process, the nylon fibers are fixed on the solid plastic rod by electrostatic spraying, and the nylon fibers are sequentially deposited on the surface of the plastic rod in a certain direction through the electrostatic field to form a brush-shaped layer.

The finished flocked swab is also sterilized with ethylene oxide (EO). Ethylene oxide gas is the most common method of sterilizing medical devices and is considered a safe and effective method to help keep medical devices safe. The sterilization process is carried out only in specially authorized and certified medical device sterilization factories, and the flocked swabs sterilized by ethylene oxide are strictly controlled before being placed on the market to ensure their safety for use.