Method for purification and identification of sperm cells
The present disclosure describes the isolation, identification and purification of aptamers having sufficiently high affinity and specificity to capture and immobilize intact sperm cells in the presence of female epithelial cells and other non-sperm semen components. The present disclosure also describes affinity-based methods for the detection of sperm cells in samples, including from forensic sample surrogates consisting of swab eluates containing a mixture of HeLa cells and sperm cells. The present disclosure describes methods for eluting sperm cell samples from swabs; methods for purifying sperm cells and methods for amplification and analysis of male DNA. The affinity-based system described herein is inexpensive, simple to use and easily implemented in forensic laboratories.
1. A method for purifying or enriching sperm cells in a sample wherein said sample is prepared by elution from a swab by contacting the swab with a buffered anionic detergent solution and wherein the detergent is Triton X-200 or sodium deoxycholate comprising:
contacting said sample with an aptamer that binds to sperm cells, thereby forming aptamer-sperm cell affinity complexes; and
partitioning the aptamer-sperm cell affinity complexes from the remainder of the sample.
2. A method for purifying sperm cells in a sample wherein said sample is prepared by elution from a swab by contacting the swab with a buffered anionic detergent solution and wherein the detergent is Triton X-200 or sodium deoxycholate comprising:
immobilizing an aptamer that has a specific affinity for sperm cells and comprising a tag to a solid support in solution;
contacting said sample with said aptamer bound solid support; thereby forming aptamer-sperm cell affinity complexes; and
partitioning the aptamer-sperm cell affinity complexes from the remainder of the sample.
3. The method of claim 1 , further comprising introducing a slow off-rate enrichment process prior to partitioning.
4. The method of claim 2 , further comprising introducing a slow off-rate enrichment process prior to partitioning.
5. A method for purifying or enriching sperm cells in a sample comprising:
treating said sample with a buffered anionic detergent wherein said detergent is Triton X-200 or sodium deoxycholate;
contacting said sample with an aptamer that binds to sperm cells, thereby forming aptamer-sperm cell affinity complexes; and
partitioning the aptamer-sperm cell affinity complexes from the remainder of the sample.
6. The method of claim 5 , further comprising introducing a slow off-rate enrichment process prior to partitioning.
7. A method for purifying sperm cells in a sample comprising:
treating said sample with a buffered anionic detergent wherein said detergent is Triton X-200 or sodium deoxycholate;
immobilizing an aptamer that has a specific affinity for sperm cells and comprising a tag to a solid support in solution;
contacting said sample with said aptamer bound solid support; thereby forming aptamer-sperm cell affinity complexes; and
partitioning the aptamer-sperm cell affinity complexes from the remainder of the sample.
8. The method of claim 7 , further comprising introducing a slow off-rate enrichment process prior to partitioning.