  Magnetic robotics obviate the physical connections between the actuators and
end effectors resulting in ultra-minimally invasive surgeries. Even though such
a wireless actuation method is highly advantageous in medical applications, the
trade-off between the applied force and miniature magnetic end effector
dimensions has been one of the main challenges in practical applications in
clinically relevant conditions. This trade-off is crucial for applications
where in-tissue penetration is required (e.g., needle access, biopsy, and
suturing). To increase the forces of such magnetic miniature end effectors to
practically useful levels, we propose an impact-force-based suturing needle
that is capable of penetrating into in-vitro and ex-vivo samples with 3-DoF
planar freedom (planar positioning and in-plane orienting). The proposed
optimized design is a custom-built 12 G needle that can generate 1.16 N
penetration force which is 56 times stronger than its magnetic counterparts
with the same size without such an impact force. By containing the fast-moving
permanent magnet within the needle in a confined tubular structure, the
movement of the overall needle remains slow and easily controllable. The
achieved force is in the range of tissue penetration limits allowing the needle
to be able to penetrate through tissues to follow a suturing method in a
teleoperated fashion. We demonstrated in-vitro needle penetration into a bacon
strip and successful suturing of a gauze mesh onto an agar gel mimicking a
hernia repair procedure.
