Apparatuses and methods for cutting porous substrates

1. An apparatus comprising:

a stripping sleeve;

a load spring;

a c-frame support having a die with an inner opening;

a pillar;

a puncher seated in the pillar and coaxially located within the stripping sleeve, and having a punch head to cut a biological sample from a substrate,

wherein:

the stripping sleeve is to hold the substrate against the die,

the load spring is to actuate the stripping sleeve to hold the substrate against the die as the punch head passes through the inner opening of the die,

the punch head is to cut the biological sample by passing through the inner opening of the die,

the puncher has a diameter at the punch head that is smaller than a diameter at an upper end of the puncher,

the stripping sleeve is movably coupled to the pillar by one or more guides and one or more channels, the one or more guides being configured to engage with the one or more channels to control relative movement between the stripping sleeve and the pillar,

when the stripping sleeve holds the substrate against the die, the one or more guides and the one or more channels allow the stripping sleeve to move relative to the puncher to compress the load spring to apply a force to the substrate,

a bottom end of the stripping sleeve forms a first shoulder against which the load spring presses to actuate the stripping sleeve when the puncher is driven towards the die,

the load spring surrounds the puncher, and is located between an inner surface of the stripping sleeve and an outer surface of the puncher, and

the stripping sleeve includes a first tapered head, and wherein the die includes a second tapered head that engages the first tapered head when the puncher is driven downward towards the die, and

the c-frame support is to hold the die in a fixed position relative to the puncher and the stripping sleeve, and

wherein the stripping sleeve includes a series of stepped shoulders formed on an inner surface thereof, the series of stepped shoulders including the first shoulder and a second shoulder disposed between the first shoulder and the first tapered head, wherein an inner diameter of the stripping sleeve varies along the inner surface of the stripping sleeve and includes at least a first diameter, a second diameter which is smaller than the first diameter, a third diameter which is smaller than the second diameter, and a fourth diameter which is smaller than the third diameter, the inner diameter transitioning from the first diameter to the second diameter at the first shoulder, the inner diameter transitioning from the second diameter to the third diameter at the second shoulder, and the inner diameter transitioning from the third diameter to the fourth diameter between the second shoulder and the first tapered head.

2. The apparatus of claim 1 , wherein a diameter of the inner opening of the die increases from an upper end to a bottom end of the die.

3. The apparatus of claim 2 , wherein the puncher is to cause a stroke of the punch head to continue through to the bottom end of the die.

4. The apparatus of claim 3 , further comprising a multi-well plate positioned under the bottom end of the die to collect the biological sample after the biological sample is ejected from the die.

5. The apparatus of claim 4 , wherein the apparatus lacks an ejector pin.

6. The apparatus of claim 1 , further comprising a ball bearing cage to permit movement of the pillar.

7. The apparatus of claim 1 , wherein the one or more channels and the one or more guides allow the stripping sleeve to move in a vertical direction when the stripping sleeve is actuated by the load spring,

wherein the puncher has a resting mode in which the one or more guides are located at an upper end of the one or more channels, and

wherein the upper end of the one or more channels form a stop for the one or more guides when the puncher is in the resting mode.

8. The apparatus of claim 7 , further comprising a retaining element that engages the one or more guides to hold the one or more guides in place against the pillar.

9. The apparatus of claim 8 , wherein the retaining element engages a notch portion to retain the one or more guides on the pillar, wherein the notch portion is wider than a head portion of the one or more guides, the head portion being received in the one or more channels, such that the notch portion forms a flange extending from the head portion.

10. The apparatus of claim 7 , wherein the one or more channels completely perforate a wall of the stripping sleeve.

11. The apparatus of claim 1 , wherein the stripping sleeve is removable from the apparatus by removing the one or more guides from one or more pin holes and sliding the stripping sleeve and the load spring away from the apparatus, and

wherein the puncher is removable from the apparatus by removing an engaging component which passes through the pillar into the puncher.

12. The apparatus of claim 1 , wherein a bottom end of the stripping sleeve extends beyond the punch head, such that the punch head is recessed within the stripping sleeve when the puncher is in a resting mode.

13. The apparatus of claim 1 , wherein the puncher is formed from aluminum.

14. The apparatus of claim 1 , wherein the stripping sleeve applies a pre-load to hold the substrate when the first tapered head of the stripping sleeve is driven downward and applies a main load, greater than the pre-load, when the punch head cuts the biological sample from the substrate and when the punch head is retracted from the substrate.

15. The apparatus of claim 1 , wherein the one or more channels each has a length which is substantially the same as a length of the die from an upper end to a bottom end of the die.