Auxetic Metamaterials for Biomedical Devices: Current Situation, Main Challenges, and Research Trends

Abstract

Auxetic metamaterials are characterized by a negative Poisson ratio (NPR) and display an unexpected property of lateral expansion when stretched and densification when compressed. Auxetic properties can be achieved by designing special microstructures, hence their classification as metamaterials, and can be manufactured with varied raw materials and methods. Since work in this field began, auxetics have been considered for different biomedical applications, as some biological tissues have auxetic-like behaviour due to their lightweight structure and morphing properties, which makes auxetics ideal for interacting with the human body. This research study is developed with the aim of presenting an updated overview of auxetic metamaterials for biomedical devices. It stands out for providing a comprehensive view of medical applications for auxetics, including a focus on prosthetics, orthotics, ergonomic appliances, performance enhancement devices, in vitro medical devices for interacting with cells, and advanced medicinal clinical products, especially tissue engineering scaffolds with living cells. Innovative design and simulation approaches for the engineering of auxetic-based products are covered, and the relevant manufacturing technologies for prototyping and producing auxetics are analysed, taking into consideration those capable of processing biomaterials and enabling multi-scale and multi-material auxetics. An engineering design rational for auxetics-based medical devices is presented with integrative purposes. Finally, key research, development and expected technological breakthroughs are discussed.

A Novel Diamine Containing Ester and Diphenylethane Groups for Colorless Polyimide with a Low Dielectric Constant and Low Water Absorption

“…With the fast growth of wireless mobile communication industries, the demand for the Internet of things (IoT), foldable displays, holograms, integrated circuits, and flexible substrates is also rapidly rising [ 1 , 2 , 3 , 4 ]. To meet these demands, the signal transmission rate and signal integrity should be high enough [ 5 , 6 ].…”

Enhanced Cellular Materials through Multiscale, Variable-Section Inner Designs: Mechanical Attributes and Neural Network Modeling

“…Metamaterials have typically been based on the design of periodic inner structural patterns that can yield macroscopic mechanical properties with fundamentally different attributes from the ones observed for the base material used [ 9 , 10 ]. This quest has fostered the engineering of advanced materials with extraordinary mechanical behaviors such as the development of auxetics [ 11 , 12 ], and thus, materials which laterally expand instead of contracting upon the application of tensile loads [ 13 , 14 , 15 , 16 ]. The aforementioned non-conventional volumetric response has been primarily materialized by re-entrant patterns, with indicative examples being the star-shaped or the re-entrant honeycomb periodic cell designs [ 17 , 18 , 19 ].…”

The Mechanical Properties of CO2‐II with Particular Emphasis on Its Auxetic Potential

“…[ 56,63,64 ] Auxetic materials have a number of advantages over materials which exhibit a positive Poisson's ratio such as enhanced indentation resistance, [ 65 ] enhanced fracture toughness, [ 66 ] and enhanced energy absorption. [ 67 ] Moreover, auxetic materials may be utilized in a number of different fields such as biomedical [ 68–74 ] and engineering applications. [ 75,76 ]…”

“…[56,63,64] Auxetic materials have a number of advantages over materials which exhibit a positive Poisson's ratio such as enhanced indentation resistance, [65] enhanced fracture toughness, [66] and enhanced energy absorption. [67] Moreover, auxetic materials may be utilized in a number of different fields such as biomedical [68][69][70][71][72][73][74] and engineering applications. [75,76] Auxetic behavior has been reported in various materials such as metals, [77][78][79][80] organic systems, [81][82][83] tendons, [84] composites, [85][86][87][88][89][90] 2D materials [91,92] zeolites, [93,94] Yukawa crystals, [95,96] face-centred cubic hard sphere crystals, [58] and silicates such as α-cristobalite, [32,33,37,40] β-cristobalite, [32,38,39] and stishovite.…”