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

Abstract

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 °C) to 32 °C 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. Graphic abstract

Design Principles for Immunomodulatory Biomaterials

“…191−193 These examples seem trivial and crude compared to the biomaterial-based implants, sutures, and prosthetics (Figures 8b,c) used in contemporary medical practice. 194,195 Still, they illustrate the historical context behind using materials to repair or augment body functions. The late 19th and early 20th centuries marked a pivotal moment in the field of biomaterials because improved scientific understanding and advanced engineering methods shifted the paradigm toward rationally designed synthetic polymers, metal alloys, and ceramics for biomedical applications.…”

“…Further, the ancient Egyptians and indigenous Maya peoples engineered crude materials from plants and animals for medical applications. For example, the ancient Egyptians replaced amputated great toes of the right foot with a prosthetic constructed from leather and wood (Figure a), while the Maya people fabricated seashells into nacre teeth that integrated seamlessly into the bone. − These examples seem trivial and crude compared to the biomaterial-based implants, sutures, and prosthetics (Figures b,c) used in contemporary medical practice. , Still, they illustrate the historical context behind using materials to repair or augment body functions.…”

“…(a) A prosthetic toe used by ancient Egyptians to replace a missing toe (reproduced with permission from ref ). (b) A nickel–titanium (NiTi) needleless wire suture for simple self-tightening surgical procedures (reproduced with permission from ref and available under a Creative Commons CC BY license). (c) A bioresorbable wireless sensor implant for in vivo pressure measurement.…”