Advancements in Soft-Tissue Prosthetics Part B: The Chemistry of Imitating Life

Abstract

Each year, congenital defects, trauma or cancer often results in considerable physical disfigurement for many people worldwide. This adversely impacts their psychological, social and economic outlook, leading to poor life experiences and negative health outcomes. In many cases of soft tissue disfigurement, highly personalized prostheses are available to restore both aesthetics and function. As discussed in part A of this review, key to the success of any soft tissue prosthetic is the fundamental properties of the materials. This determines the maximum attainable level of aesthetics, attachment mechanisms, fabrication complexity, cost, and robustness. Since the earlymid 20th century, polymers have completely replaced natural materials in prosthetics, with advances in both material properties and fabrication techniques leading to significantly improved capabilities. In part A, we discussed the history of polymers in prosthetics, their ideal properties, and the application of polymers in prostheses for the ear, nose, eye, breast and finger. We also reviewed the latest developments in advanced manufacturing and 3D printing, including different fabrication technologies and new and upcoming materials. In this review, Part B, we detail the chemistry of the most commonly used synthetic polymers in soft tissue prosthetics; silicone, acrylic resin, vinyl polymer, and polyurethane elastomer. For each polymer, we briefly discuss their history before detailing their chemistry and fabrication processes. We also discuss degradation of the polymer in the context of their application in prosthetics, including time and weathering, the impact of skin secretions, microbial growth and cleaning and disinfecting. Although advanced manufacturing promises new fabrication capabilities using exotic synthetic polymers with programmable material properties, silicones and acrylics remain the most commonly used materials in prosthetics today. As research in this field progresses, development of new variations and fabrication techniques based on these synthetic polymers will lead to even better and more robust soft tissue prosthetics, with improved lifelike aesthetics and lower cost manufacturing.

Effect of Accelerated Aging on the Sorption and Solubility Percentages of Silicone Facial Prostheses

“…Congenital defects, trauma, or cancer can often cause facial tissue disfigurement, leading to distress, few job opportunities, bullying, and discrimination for people with this problem. 1 Therefore, facial defects can negatively affect the individual's social, economic, and psychological well-being. 1 Facial prostheses may be used to rehabilitate patients with orofacial defects because they help to restore the patient's self-esteem, quality of life, esthetics, and social life.…”

“…1 Therefore, facial defects can negatively affect the individual's social, economic, and psychological well-being. 1 Facial prostheses may be used to rehabilitate patients with orofacial defects because they help to restore the patient's self-esteem, quality of life, esthetics, and social life. [2][3][4][5][6][7][8] Silicone elastomer is the most used option to manufacture maxillofacial prostheses.…”

“…[2][3][4][5][6][7] The advantage of this type of material is its ability to imitate human skin tissue both aesthetically and functionally. 1,4 The MDX4-4210 and A-2186 silicones are examples of two widely used silicones. [5][6][7]9 The degradation of the physical and mechanical properties of a silicone prosthesis is related to its exposure to ultraviolet rays, polluted air, and humidity, as well as its inadequate cleaning and daily handling.…”

Amphiphilic and segmented polyurethanes based on poly(ε-caprolactone)diol and poly(2-ethyl-2-oxazoline)diol: Synthesis, properties, and a preliminary performance study of the 3D printing

“…Several studies suggest that PU can be used in health improvements such as prothesis development, tissue engineering and tissue regeneration, and controlled drug release systems. [5,[15][16][17][18][19][20][21][22] Recently, elastomeric polyurethanes have been used to 3D print protheses, implants, and systems that mimic the human system. [23][24][25] Among the available polyols, poly(-caprolactone) (PCL) is a well suited polymer to be used in the preparation of segmented PU, since it is biodegradable, nontoxic and approved by the Food and Drug Administration (FDA).…”

Enrichment of leukocytes in peripheral blood using 3D printed tubes

“…Compared with traditional processing technology, 3D printing technology have incomparable flexibility and accuracy [16]. Several 3D printing materials have biocompatibility, which can meet the research and application needs of biological sciences and medicine [17]. Meanwhile, the manufacturing cost of 3D-printing technology is cheap, which has a very positive significance for the application and promotion of disposable biomedical microdevices [18,19].…”