Pneumatic delivery of untethered microgrippers for minimally invasive biopsy.

The surgical biopsy is one of the most widely utilized medical procedures for diagnosis of a number of diseases. In order to enable less invasive biopsies, we have previously developed and applied residual stress and physiologically activated sub-millimeter sized untethered grippers. Here, we report a controlled, pneumatic system and methodology for pressurized delivery of untethered microgrippers (μ-grippers) to improve the efficacy of tissue excision. The approach is compatible with current minimally invasive laparoscopic and endoscopic methods. Using a model experimental system, we observed that pneumatic delivery significantly improves the efficiency of the tissue attachment-μ-grippers attach up to 30-fold better on vertically oriented tissues, and up to 3.5-fold better on horizontally oriented tissues as compared to experiments without pressurized delivery. Hence, the use of pneumatics in the delivery of untethered microdevices could significantly enhance their efficiency in minimally invasive biopsy procedures.