Photo-damage method for sorting particles
View Patent ↗A system and method for sorting a mixture of stained particles in a fluid flow path, including stained particles from two distinguishable groups. The system and method can include an electromagnetic radiation source for exciting fluorescence emissions from the stained particles, a photodetector for detecting the fluorescence emissions from the stained particles, a processor for classifying the stained particles; and a photo-damaging laser for damaging selected particles in the flow path.
1. A method of sorting a mixture of stained sperm cells having either characteristic A or characteristic B into at least one population, the method comprising the steps of:
a. flowing a fluid stream containing stained sperm cells through a flow path at a fluid delivery rate;
b. exciting fluorescence emissions from the stained sperm cells having characteristic A and the stained sperm cells having characteristic B flowing in the flow path;
c. detecting the fluorescence emissions from the excited sperm cells;
d. classifying the stained sperm cells as either having characteristic A or having characteristic B based upon the fluorescence emissions;
e. selecting stained sperm cells in the flow path based on their classification; and
f. photo-damaging the selected sperm cells to produce an enriched population of sperm with respect to either characteristic A or characteristic B.
2. A method of sorting a mixture of stained sperm cells according to claim 1 wherein the step of selecting stained sperm cells in the flow path to photo-damage further comprises the step of photo-damaging sperm cells based upon a sort strategy.
3. A method of sorting a mixture of stained sperm cells according to claim 2 further comprising the step of varying the sort strategy as a function of at least one of the following:
a. the purity of the said at least one population with respect to either characteristic A sperm cells or characteristic B sperm cells; and
b. the quantity of undamaged characteristic A sperm cells or undamaged characteristic B sperm cells in the said at least one population relative to the total quantity of characteristic A sperm cells or characteristic B sperm cells in the fluid stream.
4. A method of sorting a mixture of stained sperm cells according to claim 2 further comprising the step of varying the fluid delivery rate as a function of at least one of the following:
a. the purity of the said at least one population with respect to either characteristic A sperm cells or characteristic B sperm cells; and
b. the quantity of undamaged characteristic A sperm cells or undamaged characteristic B sperm cells in the said at least one population relative to the total quantity of characteristic A sperm cells or characteristic B sperm cells in the fluid stream.
5. A method of sorting a mixture of stained sperm cells according to claim 1 , wherein the method further includes the step of forming the fluid into a stream containing sperm cells following generally one after another in a series which includes sequential sets of sperm cells, including:
a. first particle sets each including one or more sperm cells having characteristic A;
b. second particle sets each including one or more sperm cells having characteristic B; and
c. third particle sets each including two or more closely spaced sperm cells at least one of which has characteristic A and at least one of which has characteristic B.
6. A method of sorting a mixture of stained sperm cells according to claim 5 , the method further includes the step of either photo-damaging the second particles sets and not the first and third particle sets or photo-damaging the second and third particle sets and not the first particle sets.
7. A method of sorting a mixture of stained sperm cells according to claim 1 wherein characteristic A is indicative of a live X-chromosome bearing sperm cell (X) and wherein characteristic B is indicative of something other than a live X-chromosome bearing sperm cell (˜X).
8. A method of sorting a mixture of stained sperm cells according to claim 1 , wherein characteristic A is indicative of a live Y-chromosome bearing sperm cell (Y) and wherein characteristic B is indicative of something other than a live Y-chromosome bearing sperm cell (˜Y).
9. A method of sorting a mixture of stained sperm cells according to claim 1 , further comprising the step of increasing the fluid delivery rate when the purity of the said at least one population is greater than a desired purity and decreasing the rate of fluid delivery when the purity is less than the desired purity.
10. A method of sorting a mixture of stained sperm cells according to claim 1 further comprising the step of increasing the fluid delivery rate when the quantity of undamaged characteristic A sperm cells in the said at least one population is greater than an acceptable quantity of undamaged characteristic A sperm cells in the at least one population, and decreasing the rate of fluid delivery when the quantity of undamaged characteristic A sperm cells in the said at least one population is less than the acceptable quantity.