This study investigates mosquito proboscis-inspired (MPI) insertion applied to the clinically used biopsy needle to reduce tissue deformation and organ displacement. Advanced medical imagining has enabled early-stage identification of cancerous lesions that require needle biopsy for minimally invasive tissue sampling and pathological analysis. Accurate cancer diagnosis depends on the accuracy of needle deployment to the targeted cancerous lesion site. However, currently available needle delivery systems deform and move soft tissue and organs, leading to a non-diagnostic biopsy or undersampling of the target. Two features inspired by the mosquito proboscis were adopted for MPI insertion in prostate biopsy: (1) the harpoon-shape notches at the needle tip and (2) reciprocating needle-cannula motions for incremental insertion. the local tissue deformation and global prostate displacement during the MPI vs. traditional direct insertions were quantified by optically tracking the displacement of particle-embedded tissue-mimicking phantoms. Results show that the MPI needle insertion reduced both local tissue deformation and global prostate displacement because of the opposite needle-cannula motions and notches which stabilized and reduced the tissue deformation during insertion. Findings provide proof of concept for MPI insertion in the clinical biopsy procedures as well as insights of needle-tissue interaction for future biopsy technology development. Mosquito proboscis is an ideal needle device which minimizes the deformation and displacement of surrounding tissue during insertion for accurate guidance to targeted vessels. The proboscis has a hollow labrum (about 25 μm wide) and two maxillae (about 15 μm wide) with harpoon-shape notches on the side 1 as shown in Fig. 1a. During insertion, the proboscis advances incrementally with vibratory relative displacements of the labrum and maxillae for reciprocating tissue penetration 2,3. A study proposed the mechanism of proboscis insertion 1 as illustrated in Fig. 1b. In Step 1, the left maxilla moves forward into the tissue while the labrum retracts a shorter distance in the opposite direction. In Step 2, the labrum moves forward while the maxillae retract utilizing their notches to anchor the surrounding tissue. The forward motion of the right maxilla and backward motion of the labrum in Step 3 mirror the motions in Step 1. In Step 4, movements of both maxillae and the labrum in Step 2 are repeated. After moving the left maxilla forward and the labrum backward in Step 5, the relative positions of the maxillae and labrum are the same as in Step 1. At this state, the proboscis has moved forward by a distance marked by the wide arrow in Fig. 1b. By repeating the above steps, the proboscis incrementally advances with vibratory motions. The vibratory reciprocating motions of mosquito proboscis have been found to reduce insertion force and resultant tissue deformation 3,4. The harpoon-shape notches of the maxillae may further provide critical support and anchoring to reduce tissu...