DNA extraction method

In the criminal cases, the majority of theft cases have the characteristics of high incidence and low detection rate, and the anti-reconnaissance consciousness of criminals is gradually increasing. At times of committing crimes, shoe covers, gloves and headgear are often used to bring about some difficulties in field evidence collection .

For cases of theft on balconies, criminals often cling to the floor without gloves when climbing, leaving exfoliated cells at the site of contact. しかし, due to its difficult to be found and extraction and many other factors, the direct impact on the site of biological samples and post-DNA testing

この場合, it is possible to obtain the DNA typing of the criminals by extracting and testing the skin contact site of the crime scene. しかし, how to determine the extraction range and choose the extraction method according to the specific situation is the key factor that determines the success of the inspection.

Common methods of extraction are sticking, adsorption, swab transfer and other methods, while the traditional extraction method using secondary transfer brings DNA loss, pollution and other risks. In this experiment, flocking swabs were used for extraction. The swabs were easily broken at the preset breaking point to enter the tubes for direct extraction and to improve the success rate of the tests

Flock swabs are recently introduced as a DNA extraction method on the market, long hand lengths and different specifications of swab swabs to provide first-dimension swab top advantages, rapid adsorption capacity and excellent release efficiency Limited or trace DNA provides a guarantee, especially for room and contact with exfoliative cells. Ordinary cotton swab is made of thousands
Rice fiber wound around the top of the plastic rod formed a matrix environment, the arrangement of many gaps, the adhesion of cells trapped in these gaps, it is difficult to be released. Flocked swabs utilize patented Nippon fiber flocking technology to maximize DNA extraction and elution efficiency. Unlike traditional cotton swabs, the flock swab designs a brush-like structure – the nylon fibers are perpendicular to the substrate so that the entire sample collection area has no internal absorption holes and will not scatter and retain in the fibers, resulting in more Faster and more efficient elution.
加えて, flocking swabs have a strong antibacterial effect, the sample can be directly transferred to the tube without drying, can withstand more humid conditions in order to achieve the efficient transfer of cells to obtain the maximum useful evidence information

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