Capturing any amount of black hole or neutron star material is currently beyond the technological capabilities of humans. Black holes and neutron stars are incredibly dense and massive objects with intense gravitational forces.
A black hole forms from the collapse of a massive star, creating a region of spacetime with a gravitational field so strong that nothing, not even light, can escape from it. Similarly, a neutron star is the remnant of a massive star that has undergone a supernova explosion. Neutron stars are incredibly dense, with a mass several times that of the Sun packed into a sphere of only a few kilometers in diameter.
The gravitational pull near these objects is so powerful that capturing even the smallest amount of material from a black hole or neutron star would require technology and methods that are currently well beyond our reach. The extreme conditions near these objects, such as intense radiation, extreme temperatures, and strong tidal forces, make it extremely challenging to approach or manipulate them.
Furthermore, the material near black holes and neutron stars is often in the form of hot accretion disks or powerful jets of particles, which would pose significant dangers to any human-made spacecraft attempting to get close.
In summary, capturing any amount of black hole or neutron star material is currently not feasible with our current technology and understanding of these objects.