Biomaterials Application: Implants

Abstract

Biomaterials are a class of materials used for a wide range of therapeutic and diagnostic applications inside the body cavity without severe side effects. Structural components derived from biomaterials can successfully mimic the function of tissue and integrate with a biological system. Biomaterials and their implants are widely used in a variety of applications, but this chapter will focus on those used in skeletal, skin, cardiac, neuronal, and ocular implants. Skeletal implants have been designed and used to enable locomotion for centuries. The first-generation implants were derived from metals primarily for load-bearing without any bioactivity. However, the generation implants focused on the use of a variety of biomaterials including polymers, bioceramics, and their composites, as well as bioactive factors to improve their performance and integration with host tissue. Skin implants are typically made of natural and synthetic polymers as well as their composites in the form of wound coverings, bioactive bandages, and scaffolds to deliver bioactive agents and cells to promote wound healing. Cardiac implants are designed to mimic the electroactive nature of the tissue and are derived from a decellularized extracellular matrix (ECM) and conductive materials to enable electrical recording and stimulation. Similarly, neural tissue implants also focus on the use of electroactive scaffolds along with factors and cells to promote neural tissue and axonal regeneration. A wide variety of ocular implants, including contact lenses, keratoprostheses, and intraocular lenses have been developed and are mainly used for vision correction. The chapter will also provide an overview of biomaterial and implant applications in cosmetic surgeries, medical devices, and equipment. The chapter will also cover the more recent progress in biomaterials and implants that can truly mimic the function of specific tissues to improve healing outcomes.

Graphical Abstract

Questions and Answers with Explanation

• Question 1: Collagen and hydroxyapatite in the bone are produced by

  • (a) Osteoclasts

  • (b) Osteoblasts

  • (c) Haversian canal

  • (d) Bone marrow

• Explanation: Osteoblasts are the cells which are responsible for making new bone. The new is composed of collagen and hydroxyapatite which is produced by osteoblastic cells during proliferation.

• Question 2: Which is considered as gold standard in bone and skin implants

  • (a) Allograft

  • (b) Autograft

  • (c) Xenograft

  • (d) Nanograft

• Explanation: Autograft is considered as gold standard in bone and skin implants due to the fact that it is derived from patient’s own body part hence they do not produce any immunogenic response which is commonly seen in allograft and xenograft.

• Question 3: Disadvantage of synthetic biomaterial is

  • (a) Low biocompatibility

  • (b) Low cost

  • (c) High tensile strength

  • (d) Ease of manufacture

• Explanation: Synthetic biomaterials are easy to manufacture, are low cost, and have high tensile strength although, due to their synthetic nature they are not able to mimic the human structures and thus have low biocompatibility as a disadvantage.

• Question 4: Decellularized extracellular matrix is most commonly used in the manufacture of

  • (a) Skin implants

  • (b) Neuronal implants

  • (c) Cardiac implants

  • (d) Skeletal implants

• Explanation: Decellularized extracellular matrix is used in all of the above implants although it is most commonly used in manufacturing Cardica implants as the cardiac tissue is most susceptible to any of the other biomaterials.

• Question 5: Dacron® a synthetic graft goes by the chemical name of

  • (a) Polyethylene

  • (b) Poly-lactide-co-glycolide

  • (c) Polycaprolactone

  • (d) Polytetrafluoroethylene

• Explanation: Dacron® is a commercial name for synthetic graft made from polytetrafluoroethylene. It is a non-biodegradable biomaterial.

• Question 6: Which was the first biomaterial to display promising result in neuronal growth

  • (a) Collagen

  • (b) Chitin

  • (c) Keratin

  • (d) Alginate

• Explanation: Keratin was one of the first biomaterial which displayed promising results of neuronal growth. This paved the way for nerve regeneration.

• Question 7: Which type of implants are used after evisceration or enucleation

  • (a) Orbital implants

  • (b) Keratoprostheses

  • (c) Contact lenses

  • (d) Scleral buckles

• Explanation: Removal of some part of eyeball is called as evisceration whereas removal of complete eyeball is called as enucleation. In both the cases, orbital eye implants are commonly used to mimic or replace the eyeball.

• Question 8: Which is the most commonly used material in preparation of hard contact lenses

  • (a) PGA

  • (b) PLA

  • (c) PVA

  • (d) PMMA

• Explanation: Hard contact lenses are commonly manufactured using polymethyl methacrylate or PMMA due to its biocompatibility and ease of manufacturing.

• Question 9: PLA and PGA biodegradable sutures are also known as

  • (a) Vicryl

  • (b) Apligraf

  • (c) Integra

  • (d) Osteofil

• Explanation: Vicryl is a commonly used alternative name for suture having polylactic and polyglycolic acid (PLA and PGA). Apligraf and Integra are commercially available collagen scaffolds for skin regeneration whereas Osteofil is commercially available allograft bone paste.

• Question 10: Which of the following metals is used in pacemaker wiring

  • (a) Copper

  • (b) Gold

  • (c) Chromium

  • (d) Titanium

• Explanation: Pacemaker wiring is commonly made from gold as it is a non-reactive metal and does not cause any immunogenic response in the body after implantation.