Photodynamic Inactivation of Bacteria in Boar Semen with Blue LED Light

Area of Science:

• Veterinary Science
• Biotechnology
• Microbiology

Background:

• Photodynamic inactivation (PDI) offers an antibiotic alternative for boar semen preservation.
• Current PDI methods use high photosensitizer concentrations (2 µM TMPyP) and white LED light, requiring dark handling to prevent ambient light interference.
• High photosensitizer concentrations can lead to uncontrolled photodynamic effects from ambient light.

Purpose of the Study:

• To investigate the efficacy of lower photosensitizer concentrations (PS) with narrow-band blue LED light for boar semen PDI.
• To assess sperm viability and antimicrobial effectiveness under modified PDI conditions.
• To determine if reduced photosensitizer concentration and blue light minimize light-induced disruption during semen handling.

Main Methods:

• Conducted a dose-response study of blue LED light exposure on sperm to evaluate toxicity.
• Replaced white LED light with narrow-band blue LED light, targeting the TMPyP Soret band.
• Utilized a reduced TMPyP concentration of 0.5 µM in boar semen extenders.

Main Results:

• Blue LED light exposure showed no toxicity to sperm.
• Photodynamic inactivation using 0.5 µM TMPyP and blue LED light demonstrated potent antimicrobial activity.
• Sperm compatibility was maintained in long-term stored semen samples under the optimized PDI conditions.
• The modified PDI method allows for semen handling in ambient laboratory light without adverse effects.

Conclusions:

• A lower TMPyP concentration (0.5 µM) combined with blue LED light is effective for bacterial PDI in boar semen.
• This optimized PDI protocol enhances practicality by enabling semen handling under normal laboratory lighting conditions.
• The study validates a more robust and user-friendly PDI approach for boar semen preservation, reducing susceptibility to ambient light interference.