Proof of concept of a self-tightening needle-less suture using a NiTi shapememory alloy

Among surgical procedures,suturing is considered simple.However,in some situations,suturing is not easy or feasible.Here,we present proof of concept of a new self-tightening needle-less suture made of a NiTi alloy.The new device is designed to overcome two demanding steps of traditional suturing:needle introduction and manual knotting.Our novel suture is composed only of a short NiTi wire that is able to change shape by exploiting a thermoelastic phase transition.This shape change is achieved by increasing the temperature from that of the operating room(e.g.,20-22℃)to 32℃using warm water.Suturing consists of two steps:suture introduction,in which the suture is in an open configuration,and shape recovery(i.e.,closed configuration).The closed configuration is maintained at human body temperature thanks to peculiar pseudoelastic properties of the NiTi material.Finally,thermal and functional characterization verified the simplicity and effectiveness of the proposed device.