Recent Advances in Biodegradable Metals for Medical Sutures: A Critical Review

Abstract

Sutures that biodegrade and dissolve over a period of several weeks are in great demand to stitch wounds and surgical incisions. These new materials are receiving increased acceptance across surgical procedures whenever permanent sutures and long-term care are not needed. Unfortunately, both inflammatory responses and adverse local tissue reactions in the close-to-stitching environment are often reported for biodegradable polymeric sutures currently used by the medical community. While bioabsorbable metals are predominantly investigated and tested for vascular stent or osteosynthesis applications, they also appear to possess adequate bio-compatibility, mechanical properties, and corrosion stability to replace biodegradable polymeric sutures. In this Review, biodegradable alloys made of iron, magnesium, and zinc are critically evaluated as potential materials for the manufacturing of soft and hard tissue sutures. In the case of soft tissue closing and stitching, these metals have to compete against currently available degradable polymers. In the case of hard tissue closing and stitching, biodegradable sternal wires could replace the permanent sutures made of stainless steel or titanium alloys. This Review discusses the specific materials and degradation properties required by all suture materials, summarizes current suture testing protocols and provides a well-grounded direction for the potential future development of biodegradable metal based sutures.

Biodegradable Metallic Wires in Dental and Orthopedic Applications: A Review

“…Although there is a gap between in vitro and in vivo results regarding the corrosion mechanism of Mg [39], commonly for both in vitro and in vivo the oxide film formed on the surface of Mg is porous rather than dense, thus cannot effectively prevent direct contact between metallic Mg and solution, leading to the rapid degradation of Mg and its alloys. The reduction in the mechanical stability due to the stress corrosion cracking is the first negative consequence related to such high corrosion rate of Mg and its alloys, risking the adequate load shielding over the tissue regeneration duration, especially in load-bearing applications [13,40]. Therefore, it is vitally important that there should be a balance between the degradation time and the healing period of damaged tissue to prevent implantation mechanical failure.…”

“…Materials that were introduced for suture applications should have high mechanical strength and integrity and should be biocompatible. It has been reported that polymers cannot withstand high loads securely and exhibit a low creep and stress relaxation resistance which limits their range of application [13]. Metallic sutures possess, in general, the higher strength and more advantageous creep and relaxation behavior than polymers, and they also show, in most of cases, good biocompatibility.…”

“…These kinds of materials, called biodegradable metals (BMs), are strong enough during the target tissue healing process and can be gradually resorbed in the human body [12,13]. The degradation of BMs mainly ascribes to electrochemical corrosion, during which process the metal atoms lose their free electrons, become cations and enter body fluids.…”

“…To that aim, up to now different biodegradable alloys have been introduced. Among them, magnesium (Mg), iron (Fe), zinc (Zn), and their alloys as biodegradable implant metals are the three main categories that are considered more than other beneficial elements such as calcium (Ca) and strontium (Sr) [13].…”

Building towards a standardised approach to biocorrosion studies: a review of factors influencing Mg corrosion in vitro pertinent to in vivo corrosion

“…These are different to traditional metallic biomaterials, which are dominated by corrosion resistant metals such as titanium, cobalt-chromium alloys and stainless steel [2]. The key application for biodegradable metals is for temporary medical implants and devices [3][4][5][6][7]. Biodegradable metals corrode and disappear after implantation.…”