An Optimized Centrifugal Method for Separation of Semen from Superabsorbent Polymers for Forensic Analysis

Area of Science:

• Forensic Science
• Biochemistry

Background:

• Semen presence confirms sexual contact in forensic investigations.
• Superabsorbent polymers (SAPs) in evidence like sanitary napkins complicate sperm DNA analysis.

Purpose of the Study:

• To evaluate the impact of SAPs on forensic DNA workflows.
• To develop an efficient method for separating spermatozoa from SAP material.

Main Methods:

• A centrifugal-filtering protocol was developed and optimized.
• The optimized method was compared to traditional top-layer excision techniques.

Main Results:

• The centrifugal-filtering method significantly increased sperm yields compared to conventional methods.
• Direct isolation without filtering led to 20% sample failure and SAP interference in DNA samples.

Conclusions:

• The described centrifugal-filtering method is a simple, effective preliminary step for forensic DNA analysis.
• This technique improves sperm visualization, DNA yield consistency, and avoids SAP interference.