Biomaterials Science: An Introduction to Materials in Medicine 3rd Edition

e1 CHAPTER I.1.2 The Nature of Matter and Materials QUESTIONS 1. Which types of intermolecular forces dominate the assembly of atoms and molecules into matter for each of these types of materials? (a) butter. (b) platinum. (c) leather. (d) wood. (e) sapphire. (f) dry ice (solid carbon dioxide). (b) platinum. (c) leather.

e1 QUESTIONS 1. The following statements characterize, in part, the goals and specific aims of an implant retrieval and evaluation program. Answer True or False. a. Determine rates, modes, and mechanisms of implant failure; b. Identify effects of patient and prosthesis factors on performance; c. Establish factors that promote implant success;

e1 QUESTIONS 1. Overview of major terminal sterilization modalities: a. What are the two dominant sterilization modalities? b. Why do so many device companies use them? c. What are their major safety concerns? 2. Please provide brief descriptions of: a. a gamma processing plant b. how gamma sterilization kills the germs

e1 QUESTIONS 1. Scan the table of contents and abstracts from the last three issues of the Journal of Biomedical Materials Research or Biomaterials. List all the surface analy- sis methods used in the articles therein and briefly describe what was learned by using them. 2. How is critical surface tension related

e1 EXERCISES 1. What is the difference between: resilience and toughness toughness and fracture toughness bulk modulus and shear modulus nominal stress and normal stress stress and strain strain and ductility strength and stiffness hardness and Weibull modulus true strain and engineering strain Youngs modulus and rubber modulus?metal that exhibits all

e1meaning that some proteins are more surface active and more adsorptive than others; (2) the chemical nature of the adsorbing surface, due to the fact that the variations in surface affinity among proteins one sees for a given surface are only fixed for that sur-face, and will differ if another

e1 QUESTIONS 1. Why do we study cells in vitro? What are some of the advantages and disadvantages of in vitro culture systems relative to in vivo? 2. What are some of the limitations with standard tissue culture plates for in vitro cell culture? 3. What are some of the ways

e1 EXERCISES 1. Think of a materials-related problem in biomedical engineering, for which there exists no current good solution: is there something that you wish a material was able to do (or do better than the material cur-rently used to perform that function)? Now consider whether biomimicry can solve the problem.

e1 PROBLEMS 1. Which of the following HAP ceramics do you believe would be the most successful in repairing a bone defect made by the excision of a large tumor in a weight-bearing bone, and why? a) Nanocrystalline HAP on a porous collagen template. b) Sintered HAP containing silicon made at

e1 QUESTIONS 1. The transformation of a solid implant into water-sol- uble material(s) is best described by the term bioero- sion. Which of the following events may or may not accompany bioerosion? (a) Changes in the physico-mechanical properties of the polymer. (b) Cleavage of chemical bonds in the backbone of the polymer. (c)

e1 QUESTIONS 1. Calculating share price, post money, and pre-money valuations. A new company needs to raise a $5,000,000 (series A) investment, and they are negotiating pre-money valu- ation with a venture firm. They also expect to require a $10,000,000 second round (series B) of funding in three years to bring their technology

e1 QUESTIONS 1. Alginic acid is a polysaccharide derived from algae and is commonly used in foods, for cell encapsula- tion, and in molecular biology. How is sodium algi-nate different from sodium hyaluronate chemically? How does alginate differ from HA biologically? 2. Depending on the source, CS structures can vary in the

e1 QUESTIONS 1. Name at least four mechanisms that may hold a hydrogel together without covalent bonds. 2. Temperature-responsive hydrogels collapse at the LCST because: (a) their chains crystallize; (b) the complexation; (f) stereocomplex formation; (g) crystallite formation. 2. Temperature-responsive hydrogels collapse at the LCST because: (a) their chains crystallize; (b)

e1 QUESTIONS 1. For an implanted biocompatible biomaterial, iden- tify the characteristic cell types and response dura- tion of the following responses: a . Acute inammation b. Chronic inammation c . Granulation tissue d. Foreign-body reaction e . Fibrous capsule.diates, H2O2, superoxide anion, O2, hydroxyl radical b. Enzymes c . Granulation tissue d.

e1 QUESTIONS 1. Briey define the following, using examples where applicable: a. angiogenesis b. osteointegration c. stress shielding d. enucleation e. hydroxyapatite f. fibrovascularization g. capsular contracture h. micromotion i. percutaneous j. marsupialization. e. Hydroxyapatite: mineral component of bone. f. Fibrovascularization: fibrous tissue rich with blood vessels. g. Capsular contracture: the

e1 QUESTIONS 1. Draw the molecular structure represented by the shorthand notation D5. What is its chemical name? 2. What functions can llers serve in silicone elastomers? a. material extender to reduce bulk cost b. reinforce the cross-linked polymer matrix c. provide color pigmentation d. enhance visibility on X-ray e. all

e1 QUESTIONS 1. One powerful chemical species is the isocyanates group. In this chapter we have discovered that the iso- cyanates group is important in the synthesis of poly- urethanes. Do some research on the isocyanate group and write a brief ( to page) paragraph discussing its chemical reactivity.reaction also forms an unstable

e1 QUESTIONS 1. Teon is often called inert. Is it biologically inert? Explain. 2. The node-brillar morphology of ePTFE is critical to certain performances. Explain why. 3. Teon has a history of poor performance in mechanical load-bearing applications. Explain why. 4. Why is Teon white and FEP translucent in appearance?resulting fabric-like

e1 QUESTIONS 1. You are assigned the task of designing a proteomics array to the surface of a standard, glass microscope slide in a 25 25 array. Design a scheme to make such a proteomic chip. What are the important sur-face issues? Which strategies might you apply to address each of

e1 QUESTIONS 1. How would you construct a ligament prosthesis? 2. Can you design a composite plate having the same modulus as bone?gel matrix, the fibers aimed at taking the role of col-lagen fibers of the ligament. The volume fraction of PET fibers could be easily calculated by applying the

e1 QUESTIONS 1. This question is related to your knowledge of how chemical structure affects a polymers glass transition temperature. For each pair below draw the repeat unit of the polymers, select which polymer you believe has a higher glass transition temperature, and explain your answer.Pair 1: polyethylene versus poly(vinyl alcohol)Pair

e1 HOMEWORK PROBLEMS 1. Draw diagrams of the emulsification processes used to create polymer microparticles (e.g., O/W, W/O, W/O/W processes). Show the inner and outer phases, and the order in which reactants are added. Which processes would be used for hydrophobic drug encap-sulation and which for hydrophilic? Why?that these are being

e1 QUESTIONS 1. Why is the in vivo assessment of a medical device carried out? 2. What biomaterial components and characteristics may affect the overall biological responses of a medi- cal device? 3. In the selection of tests for tissue compatibility, what are the two major categories that are used? 4. Identify

e1 QUESTIONS 1. (a) What are the three most common implant alloys used in structural applications? For each one, state which element in the alloy is chosen to enhance corrosion resistance, and how they do it. (b) Describe the mechanisms of intergranular corro-sion and fretting corrosion. (c) If you had an

e1 QUESTIONS 1. The two major mechanisms of chemical degradation of polymers in vivo are hydrolysis and oxidation. Given the following polymers, indicate whether they are susceptible to hydrolysis, oxidation or both pro- cesses. If they would be highly resistant to both pro-cesses, so indicate. Poly(carbonate urethane) Poly(ether urethane) Poly(ester urethane) Aromatic

e1 EXERCISES 1. What is one advantage of PEGylation of non-viral carriers via a labile bond? 2. List three approaches for endosomal escape that have been used by non-viral vehicles.pKa ~6 for the proton sponge effect, incorporation of pH-sensitive peptides for membrane disruption. carriers via a labile bond? 2. List three approaches

e1 QUESTIONS 1. Which material property was the basis for Charles Holters selection of silicone rubber for the hydroce-phalic shunt valve? a. biostabilityImplants from The (US) National Academies Insti-tute of Medicine, available at http://www.nap.edu/books/0309065321/html/. Holters selection of silicone rubber for the hydroce-phalic shunt valve? a. biostabilityImplants from The (US) National Academies Insti-tute

e1 QUESTIONS 1. What material would you choose for a deep brain stimulating electrode, and why? Develop a simplistic equivalent circuit model for such an electrodeelec-electrode also be ideal for a cryoablation electrode (ablation due to freezing)? stimulating electrode, and why? Develop a simplistic equivalent circuit model for such an electrodeelec-electrode also

e1 EXERCISES 1. What are the three fundamental requirements of a bioelectrode? 2. What are the two fundamental types of bioelectrode charge transfer? Briey, what is the fundamental involves reductionoxidation reactions in which elec-tron transfer occurs between chemical species. Capac-itive charge transfer does not. bioelectrode? 2. What are the two fundamental types

e1 QUESTIONS 1. Classify the different types of chemical bonds within and between molecules (intra- and inter-molecular bonds. These can be expressed either as forces or as interaction energies. What is the relationship between these two physical quantities? Group these bonds in order of relative strength. In the case of hydrogen

e1 QUESTIONS 1. What are the advantages of IOL implantation over spectacles for correction of vision after removal of cataract? What other improvements have been achieved in cataract surgery over the past 35 years? 2. Which was the first biomaterial selected for IOL implant? What was the basis for this selection? achieved

e1 EXERCISES 1. List the factors that can determine if an injected depot delivery system will be successful. 2. What are the different types of techniques used to fabricate biodegradable microspheres? 3. What are the advantages of a semi-solid depot? 4. What are the four categories of injectable semi-solid temperature casting.

e1 EXERCISES 1. List the major factors causing variability of drug absorption in the GI tract. 2. Describe technologies used to achieve targeted deliv-ery in the gastrointestinal tract.a reservoir, particularly for drugs that show a sharp decrease in solubility on moving from gastric to duo-denal conditions. 2. Describe technologies used to

e1 QUESTION 1. Why would you choose an absorbable suture over non-absorbable? Or a braided suture versus a mono-lament? Or vice versa?repair, geriatric patients with slow healing wounds), known sensitivities to degradation by-products of absorbable sutures. 1. Why would you choose an absorbable suture over non-absorbable? Or a braided suture versus

e1 QUESTIONS 1. Some of the technologies replace just the dermal or epidermal components of the skin while some replace both. What are the advantages of skin substitutes that just supply one component? What are the advantages of skin substitutes that replace both? 2. A patient presents with a third degree

e1 QUESTION In deciding between a non-degradable versus a degrad- able polymer for an implantable drug delivery system, what would you need to know before proceeding with the selection? List the questions would you have, includ- ing tests that would need to be carried out. Before conducting any bench or pre-clinical testing, you should think

e1 QUESTIONS 1. Find two commercially available glucose monitors with different sensing modalities. 2. What risks are involved in the use of amperometric sensors for in vivo use? 3. How does the presence in a sample of species that cross-reacts with the target of a biosensor affect its response? 4. Describe

e1 QUESTIONS 1. What are the general mechanical property qualifica- tions for orthopedic biomaterials, and what are the major categories of orthopedic implants? 2. (a) What is the primary problem associated with the longevity of current total joint replacement implants and why? (b) How could this be solved by improved biomaterials? 3.

e1Two electrode array designs are considered. One uses a silicone substrate, and the other a liquid crystal polymer substrate. If a circular cross-section is used, with an out-side diameter of 200 m, find the force that would be exerted on a free end whose length is 1 mm and whose

e1 QUESTIONS 1. Compare the assays used to assess corrosivity and irritancy in skin substitute test systems. 2. Discuss the advantages of cryopreservation in the production of a tissue-engineered therapeutic. 3. Why is there value to adding cells other than bro-for the use of skin substitutes for the treatment of chronic

e1 QUESTIONS 1. Describe the tissue engineering paradigm as it relates to generating the myocardium. Consider the role of each component. 2. What is the advantage of regenerating the heart using tissue replacements rather than direct cell injection into the heart?tromechanically couple with the host myocardium. In contrast, implanting a functional

e1 EXERCISE You have been tasked with developing a synthetic bone graft for a young patient that has osteosarcoma of the femur. The patient is being treated with chemotherapy, and is scheduled to have the tumor removed in two weeks. The tumor removal will result in a large defect in the patients

e1 QUESTIONS 1. What are the advantages and disadvantages of cultur- ing cells on a scaffold using a bioreactor as compared to a conventional Petri dish? 2. What are the main technical requirements for tissue engineering bioreactors? 3. What are the two major challenges in the bioreactor designs, and how can one