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Biological and Biomedical Materials Overview A Paradigm for the Integration of in and

Ryan K. Roeder

The integration of biology in materi- sa, have invariably encountered several als science and engineering can be com- How would you… challenges. These challenges may be plicated by the lack of a common frame- …describe the overall significance grouped into two aspects of “biocom- of this paper? work and common language between plexity.” The materials science and engineering otherwise disparate disciplines. History paradigm was modified to account First, replace or inter- may offer a valuable lesson as modern for the adaptive and hierarchical face with biological substances, espe- materials science and engineering itself nature of biological materials. The cially tissues and cells. Biological tis- resulted from the integration of tradi- modified paradigm may be useful sues, or biological materials, are living, for the integration of biology and tionally disparate disciplines that were biomedicine in materials research and adapt to chemical and physical stimuli, delineated by classes of materials. The education, as well as in advocating perform multiple functions, and exhibit integration of , , and the application of materials science hierarchical structure with precise or- into materials science and en- and engineering principles in ganization over multiple length scales.5 biomedical research and education. gineering was facilitated, in large part, Therefore, biological materials exhibit by a unifying paradigm based upon pro- …describe this work to a materials complex processing-structure-property science and engineering professional cessing-structure-property relationships with no experience in your technical relationships, unmatched in engineering that is now well-accepted. Therefore, a specialty? materials, which are only beginning to common paradigm might also help unify Materials science and engineering is be established. the vast array of perspectives and chal- expected to play a highly significant In contrast, the vast majority of bio- lenges present in the interdisciplinary role in the foreseeable future of materials used in biomedical devices biomedicine. Conversely, noting that study of biomaterials, biological ma- materials science finds its roots in have historically included common en- terials, and biomimetic materials. The solid state physics and chemistry, gineering materials (e.g., stainless steel, traditional materials science and engi- biology is logically the next great titanium, alumina, porcelain, polyethyl- frontier for materials science and neering paradigm was modified to ac- engineering. Therefore, materials ene, polymethylmethacrylate, etc.) that count for the adaptive and hierarchical scientists and engineers who wish to exhibited desirable properties that were nature of biological materials. Various make an impact at the intersection of borrowed for biomedical applications.1,6 examples of application to research and materials and biology must become These biomaterials enhanced the quality increasingly knowledgeable, or at education are considered. least conversant, in biology and of life for countless individuals through biomedicine. passive interaction with biological sys- introduction …describe this work to a tems (bioinert). In other words, “do no Most materials scientists and engi- layperson? harm.”7 Thus, metallurgical or materials neers recognize the tremendous op- The integration of traditionally engineers were well-positioned to con- portunities available at this time in his- disparate disciplines of study can tribute to the design and manufacturing tory for advances in or be complicated by the lack of a of a conventional stainless steel implant, common framework for critical biomedicine and, closer to home, the thinking and common language for for example, through traditional educa- intersection of materials and biology. communication. The integration of tion in physical metallurgy or materials Materials science and engineering is ex- metallurgy, ceramics, and polymers structure-property relationships, with pected to play a highly significant role in into modern materials science and little consideration of biology. engineering was facilitated, in 1,2 the foreseeable future of biomedicine. large part, by a unifying paradigm A second generation of biomaterials Conversely, noting that materials sci- based upon processing-structure- began to introduce materials that are ence finds its roots in solid state physics property relationships that is favorably reactive to biology, includ- now well-accepted. Therefore, and chemistry, biology is logically the a common paradigm might ing bioactive ceramics and glasses (e.g., next great frontier for materials science also help unify the vast array of hydroxyapatite and bioglass, respective- and engineering.2–4 However, research- perspectives and challenges present ly) and biodegradable polymers (e.g., ers and educators working to integrate in the interdisciplinary study of polylactide and ).6,7 In the biomaterials, biological materials, biology or biomedicine into materials and biomimetic materials. present age, so-called third generation science and engineering, and vice ver- biomaterials are intended for proactive

Vol. 62 No. 7 • JOM www.tms.org/jom.html 49 interaction with biology.6,7 Examples may include individuals educated in lenge of integrating biology in materi- include: engineering scaffolds engineering (chemical, materials, me- als science and engineering. Modern able to guide differentiation and chanical, etc.), science (cell biology, materials science and engineering tissue growth via signal transduction;7–9 biochemisty, etc.), basic medical sci- resulted from the integration of tradi- vehicles for controlled and/or targeted ences (anatomy, pathology, pharmacol- tionally disparate disciplines that were delivery of pharmaceuticals, proteins, ogy, etc.), and clinical medicine (car- delineated by classes of materials, viz., and nucleic acids;10,11 and multifunc- diology, orthopedics, radiology, etc.). metals, ceramics, and polymers. As tional diagnostics and sensors;11–13 The diversity of thought contributed early as the 1950s materials education among others. Materials scientists and by each field of expertise is recognized was nascent, but critics suggested that engineers who wish to contribute to as a great benefit in interdisciplinary the breadth of a materials curriculum these and other exciting applications of work. However, a significant challenge without traditional demarcations be- biomaterials must become increasingly facing bioengineering as a discipline, tween material classes would compro- knowledgeable, or at least conversant, as well as the integration of biology mise depth of study.18 Proponents of in biology and biomedicine.2,3 in traditional disciplines, including materials-generic education, such as Second, biomaterials research and materials science and engineering, is Gerald L. Liedl, recognized the oppor- development requires diversity among the lack of a common framework and tunities and challenges: contributors and collaborators. For rea- common language for synthesizing the “The diversity in the field is, on one hand, a sons discussed above, no single indi- diversity of thought and expertise.3 major asset in addressing problems, but on vidual or discipline of study can be ex- See the sidebar for a glossary of bio- the other hand, a major obstacle in unifying pected to possess sufficient depth in the logical materials terminology. an educational approach. This problem is full breadth of knowledge required for not new since we have faced it over time as Lessons from Our Past 19 most biomaterials applications. Thus, information and knowledge expands.” product development teams in industry The history of materials science and Despite the pre-existing traditions and (increasingly) collaborators in use- engineering provides valuable lessons and human nature to resist change, inspired basic research in academia that can be applied to the present chal- materials science and engineering has evolved over the last fifty years into Glossaries a unified discipline of study with an identifiable, common core curricu- Intersection of Materials and Biology lum.20–23 The integration of metallurgy, 14–16 Adapted from various sources. ceramics, and polymers into materials Biological Material: A natural material produced by a biological organism. Examples science and engineering was facilitat- include , , seashells, wood, silk, etc. Biological Materials Science: The application of materials science and engineering ed in large part by a unifying paradigm principles to the study of biological materials, including the design, synthesis, and based upon the underlying principles fabrication of biomaterials and biomimetic materials from biological lessons. of processing, structure, properties, (or Biomedical Material): A synthetic material or processed biological and performance, and their interrela- material engineered to evaluate, treat, augment, or replace any component or function tionships, that is now well-accepted of a biological organism, while in continuous or intermittent contact with biological (Figure 1). substances. Interestingly, the reservations once Biomimetic Material (or Bioinspired Material): A material engineered to be physically, chemically, or functionally similar to a biological material. raised against materials education have been similarly raised against bioengi- Biological Properties of Materials neering education, as well as the inte- 7,14,17 Adapted from various sources. gration of biology in traditional disci- Bioactivity: The ability of a biomaterial to elicit or modulate a favorable response plines, including materials science and (“activity”) from any part of a biological organism. Biocompatibility: Generally refers to the response of a biological organism to engineering. Considering the history the presence of a material, not vice versa, with varied meaning. (1) The ability of a of materials science and engineering, biomaterial to perform its desired function with an appropriate host response in a specific a common paradigm might also help application.14 (2) The ability of a biomaterial to perform its desired function with respect to unify the differing backgrounds, to a medical therapy, without eliciting any undesirable local or systemic effects in the perspectives, and terminology of those recipient or beneficiary of that therapy, but generating the most appropriate beneficial who find themselves at the intersection cellular or tissue response in that specific situation, and optimizing the clinically relevant performance of that therapy.7 of materials and biology. The objective Biodegradability: The ability of a material to be broken down or decomposed by a of this paper is to introduce possible biological organism. modifications of the materials science Bioinert: The ability of a biomaterial to remain unchanged by a biological organism and engineering paradigm for the in- and to not elicit biological activity. tegration of biology. Conversely, the Bioresorbability: The ability of a material to be gradually resorbed or dissolved by modified paradigm may also be used cellular and/or metabolic processes. Bioabsorbability may be used to specify metabolism for the application of materials science of the material, and bioerodibility may be used to specify surface erosion. Toxicity: The degree to which a material may permanently destroy or impair any part and engineering principles to the study of a biological organism. of biomaterials, biological materials, and biomimetic materials.

50 www.tms.org/jom.html JOM • July 2010 vironment effects.5,15 The first three as- pects are all readily captured within the processing-structure-property scheme in Figure 1. The materials sci- ence and engineering para- Figure 2 by adding biological processes. digm showing the underly- The latter two aspects will be incorpo- ing principles at vertices rated below in proposed modifications and their interrelationships along edges of a tetrahe- of the materials science and engineering dron. The base is shaded to paradigm for the integration of biology. highlight that processing- The base of the tetrahedron in Figure structure-property relation- ships have historically re- 1 was shaded to highlight the observa- ceived greater attention by tion that processing-structure-property materials scientists and en- relationships, as discussed above (Fig- gineers than considerations of performance. ure 2), have historically received greater attention by materials scientists and common underlying mechanisms for engineers than considerations of perfor- Development of the achieving a change in shape rather than mance.23 One can readily observe that Materials Science and by classes of materials.18,24 Deforma- materials performance is often more Engineering Paradigm tion processes involve the application likely to be considered by engineers The materials science and engineer- of force to achieve a shape change via who are more concerned with an en- ing paradigm has itself evolved from crystal plasticity or viscous flow. Depo- tire engineering system rather than the a triangle to the tetrahedron shown in sition processes involve a gas or liquid intricacies of the materials used. For Figure 1.15 Aspects of the processing- to solid state change upon surfaces, such example, a mechanical engineer may structure-property vertices have been as evaporation and condensation. Pow- be concerned with how materials en- detailed in various formats similar to der processes involve the consolidation able improved efficiency in an internal that shown in Figure 2. Material prop- and densification of powders. Solidifi- combustion engine; a chemical engineer erties can be further identified in cat- cation processes involve a liquid to solid may be concerned with how materials egories based on the application. For state change via crystallization or glass enable improved efficiency in catalysis; example, properties of interest for ce- transition. or an electrical engineer may be con- ments used in bone fracture or implant cerned with how materials can sustain Modifications for the fixation include mechanical properties Moore’s Law for integrated circuits. Integration of Biology (e.g., elastic modulus, ultimate strength, Thus, the difference between mate- fracture toughness, fatigue life, and pre- A pentahedron was originally pro- rial properties and performance may be cured viscosity), chemical properties posed by Eduard Arzt25 and modified by simply a matter of perspective, or scale. (e.g., setting time and reaction yield), Marc A. Meyers to incorporate unique The overarching concept is that of func- thermal properties (e.g., exothermic aspects of biological materials, where tion, which is ironically the preferred ), and biological properties the five vertices corresponded to aque- term used in biology, and has been used (e.g., biocompatibility, bioactivity, and ous synthesis under near-ambient condi- in Michael F. Ashby’s work on materi- bioresorbability), irrespective of the ma- tions, self-assembly, multifunctionality, als selection and design.26 terial of choice (e.g., acrylic or calcium hierarchical structure, and evolution/en- Therefore, in order to account for phosphate cements). Material structure can be subdivided by aspects unique to non-crystalline versus crystalline mate- rials contained within the microstructure (Figure 2). Materials processing lagged behind structure-property relationships in the adoption of materials-generic concepts and curricula, which were proposed by Merton C. Flemings and colleagues18 and implemented by Kevin P. Trumble and colleagues.24 Chemical processing, or primary production, involves the con- version of raw materials into engineer- ing materials. Structural processing, or shape forming, involves the conversion of engineering materials into objects or components, which may be subse- Figure 2. A more detailed description of the processing-structure-property vertices of the materials science and engineering paradigm in Figure 1, showing various categories and quently assembled into a system. Shape examples. forming processes can be grouped by

Vol. 62 No. 7 • JOM www.tms.org/jom.html 51 Figure 3. A modified mate- rials science and engineer- Implications ing paradigm showing pro- for Research, Design, cessing-structure-property and Education relationships corresponding to triangles of increasing The modifications to the materi- length scale from atoms to materials to engineering als science and engineering paradigm systems. Notice that termi- (Figures 3–5) may be useful for the nology for synthesis, pro- integration of biology and biomedicine cessing and manufacturing, or properties and perfor- in materials research and education, as mance may be envisioned well as in advocating the application of to correspond to different materials science and engineering prin- length scales. “Function” is proposed to capture the ciples in biomedical research and edu- essence of both properties cation, by providing a common frame- and performance which work for critical thinking and a common were collapsed to the same vertex. language for communication for those who find themselves at the intersection the hierarchical structure of biological onstrating the ability of the paradigm to of materials and biology. Hierarchical materials, the properties and perfor- describe the development (processing), processing-structure-function relation- mance vertices in Figure 1 were col- anatomy or form (structure), function, ships provide a framework to consider lapsed together and the fourth vertex and adaptation (in response to a stimu- complex, multi-scale problems involv- was changed to represent length scale. lus) of biological systems. The stimu- ing biomaterials, biological materials, At the risk of sounding overly dramatic, lus might include mechanical loading, and biomimetic materials. Moreover, the tetrahedron in Figure 1 was then chemical gradients, electrical signals, this framework may help one to better turned upside-down, such that process- and the like. The response of tissues to appreciate the full scope and potential ing-structure-property relationships cor- implanted biomaterials, and vice versa, ramifications of a seemingly simple respond to triangles of increasing length can be readily considered hierarchically, engineering solution (e.g., systemic re- scale from atoms to materials to systems ranging from altered tissue morphology sponse to an implanted biomaterial). (Figure 3). Notice that terminology for to the release of cytokines and growth Biomaterials research and product de- synthesis, processing and manufactur- factors. Furthermore, a time scale could velopment has a history full of unintend- ing, or properties and performance are even be used to extend Figure 5 into a ed consequences, such as thrombosis, readily envisioned to correspond to dif- third-dimension. restenosis, osteolysis, allergic reactions, ferent length scales. However, this mod- ification of the materials science and engineering paradigm does not clearly account for adaption in biological mate- rials and systems. In order to represent the adaptive or cyclical nature of biological materials and systems, the triangular slices of the tetrahedron in Figure 3 were changed to circles to form an inverted cone. In order to aid visualization, the inverted cone was then projected onto a two-dimen- sional surface shown in Figure 4. Pro- cessing-structure-function relationships are shown by three sectors and the cir- cular representation reflects principles of biological adaption (“form follows function follows form”27). Hierarchical structure is shown by concentric circles of increasing length scale from atoms and molecules to materials to systems (Figure 4). Key biological principles and ter- Figure 4. A modified materials science and engineering paradigm showing levels of scale minology were readily mapped onto corresponding to concentric circles of increasing size. Processing-structure-function the modified materials science and en- relationships are shown as three sectors of a circle to reflect the dynamics of biological gineering paradigm presented above adaption. Interrelationships between sectors at each level of scale provide a framework to simultaneously consider complex multi-scale phenomena in interdisciplinary research, (Figure 5). At each scale, parallels to education, and design. biology are shown in parentheses, dem-

52 www.tms.org/jom.html JOM • July 2010 implant fracture, degradation, etc. Many aspect of a project at the molecular level in the rapidly progressing technologies were likely unavoidable due to the state may be able to better appreciate and in- requiring proactive, third-generation of knowledge at the time. Nonetheless, tegrate the work of a mechanical engi- biomaterials. a critical examination of history can re- neer at the systems level, and vice versa. The modified paradigm may be use- veal several potentially problematic In education, a “bottom-up” perspective ful for materials scientists and engineers paradigms that are described in Table on hierarchical structure may be most seeking research funding from the clini- I. Since everyone is at risk of being of- appropriate for materials scientists and cally- and biologically-oriented Nation- fended by the generalizations in Table I, chemists, but mechanical engineers, for al Institutes of Health (NIH). Materials note that each paradigm has unquestion- example, may more readily assimilate science and engineering is well-accus- ably resulted in successful biomedical content taught from a “top-down” ap- tomed as a discipline to use-inspired ba- implants which have greatly improved proach. sic research rather than the historic di- human health. However, the shortcom- Relative to other science and engi- chotomy between basic and applied re- ings of each paradigm have also clearly neering disciplines, materials science search in the United States.28 However, resulted in clinical problems, such as and engineering finds itself located in materials scientists and engineers, like those mentioned above, or a lack of clin- the center of the length scale continuum engineers from other “traditional” disci- ical solutions to date. Research and de- (Figure 4). Perhaps this is why the mate- plines, may have difficulty understand- sign based upon hierarchical processing- rials science and engineering paradigm ing and expressing the clinical signifi- structure-function relationships (Fig- was so easily adapted to the breadth of cance of their work. Thus, the modified ures 3–5) could conceivably adopt the biological systems (Figure 5). Thus, if paradigm may help the researcher to ask strengths and avoid the weaknesses of materials science and engineering as a the right questions. “If you don’t ask the each potentially problematic paradigm. discipline embraces biology, the center right questions, you won’t get the right When used in research and design can be a place of continued importance answers.”29 teams, the modified paradigm may also in enabling new systems-level biomedi- The modified paradigm may also be enable improved understanding and ap- cal technology in the same way the dis- used as a conceptual framework for de- preciation between different individu- cipline has enabled new technology in sign, including concurrent engineering als or disciplines that typically address the electronics, energy, and transporta- in product development and computa- problems from different perspectives tion industries. However, failure to em- tional design of hierarchically structured originating at different levels of scale. brace biology could result in being over- materials. Concurrent engineering is a For example, a chemist working on an looked or marginalized as a discipline systematic approach for simultaneously, rather than sequentially, considering various aspects in product development spanning concept, design, materials se- lection, manufacturing, and service.30–32 Materials science and engineering is also presently faced with new opportu- nities and challenges involving compu- tational simulation for the “bottom-up” design32 and “top-down” evaluation33 of performance in hierarchically structured materials, and the integration of compu- tational methods in curricula.34 The modified paradigm suggests that a significant number of biological concepts can be integrated into materi- als science and engineering curricula within existing common core courses. Moreover, biomaterials and biological materials can be used in these courses to stimulate interest in the underlying materials science. For example: • The structure of important proteins like collagen can be introduced alongside synthetic macromol- ecules. In processing, the synthe- Figure 5. The modified materials science and engineering paradigm in Figure 4 showing sis of proteins (polypeptides) from direct parallels to biology in parentheses and demonstrating the ability of the paradigm to amino acids by transcription/trans- describe the development (processing), anatomy or form (structure), function, and adapta- lation and their self-assembly into tion (in response to a stimulus) of biological systems. The stimulus might include mechani- cal loading, chemical gradients, electrical signals, and the like. (e.g., collagen fibrils) can be compared and con-

Vol. 62 No. 7 • JOM www.tms.org/jom.html 53 Table I. Potentially Problematic Design Paradigms Showing Key Characteristics and Examples* Design Paradigm Emphasis on… Potential problems may occur when… Driven by… Possible Clinical Examples “Material-Mart” Functionality Materials are taken “off the Physicians and Artificial heart, vascular grafts, shelf” with little initial regard for FDA policies breast implants, metallic orthopaedic processing-structure-function implants, PMMA bone cement relationships. “Make it and break it” “New” materials and Design occurs by “trial Industry and systems Dental/orthopedic composites, processing methods for an and error” with little initial level engineering porous tantalum, bioresorbable intended function consideration of the effects polymers, nitinol stents of material structure. Mimicking biology One assumes a priori that the Academics Xenografts, synthetic bone best way to achieve a desired outcome graft substitutes, synthetic collagen (function) is the way nature has done it. * Note that each paradigm has unquestionably resulted in successful implants which have greatly improved human health. However, the shortcomings of each paradigm have also resulted in clinical problems or a lack of clinical solutions. Research and design based upon hierarchical processing-structure-function relationships (Figures 3–5) could conceivably adopt the strengths and avoid the weaknesses of each potentially problematic paradigm.

trasted to the polymerization and magnetic properties of materials or interactions17 could serve as the prereq- molding of thermoplastic and ther- “functional” materials. uisite for advanced electives of special mosetting polymers. There are seemingly endless possibili- interest such as tissue engineering scaf- • Wetting of solid surfaces by liq- ties besides those listed above. Thus, folds,1,2,7–9 ,10–12 or a par- uids is usually introduced early in discretion on how much biology and ticular medical specialty (e.g., orthope- undergraduate materials curricula biomedicine to integrate into core cours- dic biomaterials). and can be coupled with examples es and curricula will ultimately fall upon Materials science and engineering and particular concepts that are im- instructors, curriculum committees, and degree programs should not inhibit or portant in biological materials. See perhaps, through the process of self- discourage students interested in bioma- “Implications of Wettability in Bio- study and review, by the Accreditation terials from venturing out of department logical Materials Science,” by John Board for Engineering and Technology to take elective courses in cell biology, A. Nychka and Molly M. Gentle- (ABET). , molecular biology, etc., man in this same issue of JOM.35 The ability to readily integrate bi- in order to add further depth in biology Moreover, early introduction to the ology into existing core courses and than is possible even with the above rec- biological significance of surface curricula does not diminish the need ommendations. Moreover, efficiencies energy can lay the groundwork for for complementary electives focused might be realized through partnership advanced electives on biocompat- exclusively on concepts key to the in- with bioengineering programs where ibility or tissue-biomaterial interac- teraction of materials and biology. The both programs could utilize an intro- tions. model of a single, catch-all course on ductory course to materials and a sub- • Composite biological materials like “biomaterials” has run its course and sequent course focused on biocompat- bone, dentin, and nacre provide should be seriously questioned due to ibility or tissue-biomaterial interactions, wonderful examples for the discus- the rapid growth of the field and the supported by the materials and bioengi- sion of hierarchical structure,5 an- need for more serious engagement with neering departments, respectively. Col- isotropy,36,37 micromechanical mod- biological concepts, as described above. laborative teaching could bring further els,37 toughening mechanisms,38 Popular textbooks on the broad subject benefits and should also be explored. and fatigue crack propagation39 in of biomaterials have been noted to be The modified paradigm (Figures 4, 5) texts and courses on the mechanical better-suited as reference books due to has been implemented in an elective bio- behavior and failure of materials. the need to introduce materials science materials course taught within the me- Furthermore, the adaptation and re- (to biomedical engineers), biological chanical engineering department (with modeling of biological materials in materials, key concepts related to in- a graduate program and undergraduate response to mechanical stimuli de- teraction of materials and biological minor in bioengineering) under my di- serves consideration for introduc- systems, and biomedical applications.41 rection for the last four years with an tion in related texts and courses, es- However, the good news for materials average enrollment of 30 students/year. pecially in light of recent interest in science and engineering, compared to Students entering the course include self-healing engineering materials. other disciplines, is that the integration seniors and first-year graduate students • Surface plasmon resonance exhib- of biology into lower-level courses, as who have already taken an introduc- ited by metallic nanoparticles and suggested above, should enable ad- tion to materials course. Therefore, the surfaces has become important in vanced, elective courses to focus en- course emphasizes hierarchical struc- biomedicine for tunable therapeu- tirely on key overarching concepts. For ture-function relationships related to tics, diagnostics, and sensors,11,40 example, an upper-level undergraduate tissue-biomaterial interactions using and could be included in courses and/or introductory graduate course on published reports in the literature (in- covering electrical, optical and biocompatibility7 or tissue-biomaterial cluding journal articles, Food and Drug

54 www.tms.org/jom.html JOM • July 2010 Administration pre-market approvals, Acknowledgements Engineering, Vol. 3, The Institutional Framework for patents, etc.) that are critically and in- Materials Science and Engineering, Supplementary dependently evaluated by teams and in- The content of this paper was de- Report of the Committee on the Survey of Materials Science and Engineering (Washington, D.C.: National dividuals. Upon completing the course veloped in the course of research Academy of Sciences, 1975), http://www.nap.edu/cat- all students demonstrate the ability to projects supported by the U.S. Army alog/10438.html. identify and organize the key hierarchi- Medical Research and Materiel Com- 21. Materials Science and Engineering for the 1990’s: Maintaining Competitiveness in the Age of Materials cal structure-function relationships into mand (USAMRMC) through the Peer (Washington, D.C.: National Academy Press, 1989), a coherent framework for the biomate- Reviewed Medical Research Program http://www.nap.edu/catalog/758.html. rials used in any biomedical application (PR054672, W81XWH-06-1-0196) and 22. The Future of Materials Science and Materials Engineering Education, A report from the Workshop without prior knowledge of that ap- the Telemedicine and Advanced Tech- on Materials Science and Materials Engineering Edu- plication. In other words, students are nologies Research Center (W81XWH- cation (Arlington, VA: National Science Foundation, able to see the entire scope of an open- 07-1-0662), the National Institutes of 2008), http://www.nsf.gov/mps/dmr/mse_081709.pdf. 23. L.H. Schwartz, “Undergraduate Materials Educa- ended biomedical problem and frame Health (AR049598), and the State of tion 2010: Status and Recommendations,” JOM, 62 (3) the role of materials within solution(s). Indiana, 21st Century Research and (2010), pp. 34–70. Most students completing the course Technology Fund. 24. K.P. Trumble, K.J. Bowman, and D.R. Gaskell, “A also demonstrate the ability to criti- General Materials Processing Curriculum,” J. Mater. References Education, 18 (3) (1996), pp. 117–123. cally evaluate shortcomings in the state 25. E. Arzt, “Biological and Artificial Attachment - De of knowledge, or application thereof, 1. R. Langer, “Biomaterials for Drug Delivery and Tissue vices: Lessons for Materials Scientists from Flies Engineering,” MRS Bull., 31 (6) (2006), pp. 477–485. and Geckos,” Mater. Sci. Eng. C, 26 (2006), pp. 1245– in light of their conceptual framework 2. G.M. Whitesides and A.P. Wong, “The Intersection 1250. using the modified paradigm. Finally, of Biology and Materials Science,” MRS Bull., 31 (1) 26. M.F. Ashby, Materials Selection in Mechanical De- some students demonstrate the ability (2006), pp. 19–27. sign (Oxford, U.K.: Pergamon Press, 1992). 3. M.H. Friedman, “Traditional Engineering in the 27. M.C.H. van der Meulen and R. Huiskes, “Why to translate their critical thinking into Biological Century: The Biotraditional Engineer,” J. Bio- Mechanobiology? A Survey Article,” J. , proposed action. mech. Eng., 123 (12) (2001), pp. 525–527. 35 (4) (2002), pp. 401–414. The modified paradigm and the im- 4. L.E. Murr, “Biological Issues in Materials Science 28. D.E. Stokes, Pasteur’s Quandrant: Basic Science and Engineering: and the Bio-Materi- and Technological Innovation (Washington, D.C.: plications discussed above are certainly als Paradigm,” JOM, 58 (7) (2006), pp. 23–33. Brookings Institute Press, 1997). not perfect or complete. One drawback 5. M.A. Meyers et al., “Biological Materials: Structure 29. E. Hodnett, The Art of Problem Solving (New York: is that the modified paradigm presented and Mechanical Properties,” Prog. Mater. Sci., 53 Harper, 1955). (2008), pp. 1–206. 30. B. Prasad, Concurrent Engineering Fundamentals. in Figures 4 and 5 is admittedly quite 6. L.L. Hench and J.M. Polak, “Third-Generation Bio- Integrated Product and Process Organization (Edge- busy. Nonetheless, the concepts and medical Materials,” Science, 295 (2002), pp. 1014– wood Cliffs, NJ: Prentice Hall, 1996). ideas presented in this article will hope- 1017. 31. B. Yazdani and C. Holmes, “Four Models of Design 7. D.F. Williams, “On the Mechanisms of Biocompatibil- Definition: Sequential, Design Centered, Concur- fully stimulate further thought, ideas, ity,” Biomaterials, 29 (2008), pp. 2941–2953. rent and Dynamic,” J. Eng. Design, 10 (1) (1999), pp. and engagement for the integration of 8. K.C. Dee and R. Bizios, “Mini-Review: Proactive Bio- 25–37. biology in materials science and engi- materials and Bone Tissue Engineering,” Biotechnol. 32. D. L. McDowell, “Simulation-Assisted Materials Bioeng., 50 (4) (1996), pp. 438–442. Design for the Concurrent Design of Materials and neering. 9. D.L. Butler, S.A. Goldstein and F. Guilak, “Functional Products,” JOM, 59 (9) (2007), pp. 21–25. Tissue Engineering: The Role of Biomechanics,” J. Bio- 33. G.B. Olson, “Computational Design of Hierarchi- Conclusions mech. Eng., 122 (12) (2000), pp. 570–575. cally Structured Materials,” Science, 277 (1997), pp. 10. D. Peer et al., “Nanocarriers as an Emerging Plat- 1237–1242. Materials scientists and engineers form for Cancer Therapy,” Nat. Nanotechnol., 2 (2007), 34. K. Thornton et al., “Computational Materials Sci- who wish to make an impact in re- pp. 751–760. ence and Engineering Education: A Survey of Trends search and technology at the intersec- 11. M. De, P.S. Ghosh, and V.M. Rotello, “Applications and Needs,” JOM, 61 (10) (2009), pp. 12–17. of Nanoparticles in Biology,” Adv. Mater., 20 (2008), pp. 35. J.A. Nychka and M.M. Gentleman, “Implications tion of materials and biology must 4225–4241. of Wettability in Biological Materials Science,” in this become increasingly knowledgeable, 12. P. Wu, D.G. Castner and D.W. Grainger, “Diagnostic issue. or at least conversant, in biology and Devices as Biomaterials: A Review of Nucleic Acid and 36. K. Bowman, Mechanical Behavior of Materials Protein Microarray Surface Performance Issues,” J. Bio- (New York: John Wiley and Sons, Inc., 2004). biomedicine. Therefore, the materials mater. Sci. Ed., 19 (6) (2008), pp. 725–753. 37. J.M. Deuerling et al., “Specimen-specific Multiscale science and engineering paradigm was 13. M. Sarikaya et al., “Molecular Biomimetics: Nano- Model for the Anisotropic Elastic Constants of Human modified to account for the adaptive technology through Biology,” Nat. Mater., 2 (2003), pp. Cortical Bone,” J. Biomechanics, 42 (13) (2009), pp. 577–585. 2061–2067. and hierarchical nature of biological 14. D.F. Williams, The Williams Dictionary of Biomateri- 38. J.W. Ager III, G. Balooch, and R.O. Ritchie, “Frac- materials. Hierarchical processing- als (Liverpool, U.K.: Liverpool University Press, 1999). ture, Aging, and Disease in Bone,” J. Mater. Res., 21 structure-function relationships pro- 15. M.A. Meyers, A.M. Hodge, and R.K. Roeder, “Bio- (8) (2006), pp. 1878–1892. logical Materials Science and Engineering: Biological 39. J.J. Kruzic and R.O. Ritchie, “Fatigue of Mineralized vide a framework for critical thinking Materials, Biomaterials, and Biomimetics,” JOM, 60 (6) Tissues: Cortical Bone and Dentin,” J. Mech. Behav. involving complex, multi-scale prob- (2008), pp. 21–22. Biomed. Mater., 1 (1) (2008), pp. 3–17. lems involving biomaterials, biological 16. D.F. Williams, “On the Nature of Biomaterials,” Bio- 40. L.M. Liz-Marzán, “Tailoring Surface Plasmons materials, 30 (2009), pp. 5897–5909. through the Morphology and Assembly of Metal materials, and biomimetic materials. 17. K.C. Dee, D.A. Puleo, and R. Bizios, Tissue-Bio- Nanoparticles,” Langmuir, 22 (2006), pp. 32–41. The modified paradigm may be use- material Interactions (New York: John Wiley and Sons, 41. J. Andrade, “Biomaterials I: Past, Present, and ful for the integration of biology and 2002). Future,” Education Summit 18. M.C. Flemings, K.F. Jensen, and A. Mortensen, (Arlington, VA: Whitaker Foundation, 2000). biomedicine in materials research and “Proposal for a Generic Materials Processing Course,” education, as well as in advocating the MRS Bull., 15 (8) (1990), pp. 35–36. Ryan K. Roeder, Associate Professor, is with the application of materials science and 19. G.L. Liedl, “The Emerging Undergraduate Curricula Department of Aerospace and Mechanical Engi- in Materials Science and Engineering,” MRS Bull., 15 neering, Bioengineering Graduate Program, 148 engineering principles in biomedical (8) (1990), pp. 31–34. Multidisciplinary Research Building, Notre Dame, research and education. 20. Materials and Man’s Needs: Materials Science and Indiana 46556; e-mail: [email protected].

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