Fundamental of Biomaterials BME310 PDF

Faculty of Engineering Department of Medical Engineering Fundamental of Biomaterials BME310  Carbon as a Biomaterial Carbon is an element found abundantly in the Earth’s crust and in the human body. The various bonding capabilities en...

Faculty of Engineering Department of Medical Engineering Fundamental of Biomaterials BME310  Carbon as a Biomaterial Carbon is an element found abundantly in the Earth’s crust and in the human body. The various bonding capabilities enable it to form so ُ‫ خس‬ٟ‫ف‬ٚ ‫خ‬١‫ اٌمششح األسػ‬ٟ‫د ثىثشح ف‬ٛ‫خ‬ِٛ ‫ ػٕظش‬ٛ٘ ْٛ‫اٌىشث‬ many different varieties of compounds including the many gases, ‫اع‬ٛٔ‫ذ ِٓ أ‬٠‫ٓ اٌؼذ‬٠ٛ‫ػخ ِٓ رى‬ٕٛ‫ رّىٕٗ لذساد اٌزشاثؾ اٌّز‬.ْ‫اإلٔسب‬ liquids, and solids. ‫اد‬ٌّٛ‫ا‬ٚ ً‫ائ‬ٛ‫اٌغ‬ٚ ‫ذ ِٓ اٌغبصاد‬٠‫ رٌه اٌؼذ‬ٟ‫اٌّشوجبد اٌّخزٍفخ ثّب ف‬ The carbon compounds constitute the nutrients, the organic energy.‫اٌظٍجخ‬ sources, the building materials for plants, and many other molecules ‫خ‬٠ٛ‫ِظبدس اٌطبلخ اٌؼؼ‬ٚ ‫خ‬١‫ْ اٌؼٕبطش اٌغزائ‬ٛ‫رشىً ِشوجبد اٌىشث‬ in the body. Since all living species are hydrocarbon based, carbon basically is the element of life if water is the molecule of life. ‫ثّب‬ٚ.ُ‫ اٌدس‬ٟ‫ ف‬ٜ‫ئبد األخش‬٠‫ذ ِٓ اٌدض‬٠‫اٌؼذ‬ٚ ‫اد اٌجٕبء ٌٍٕجبربد‬ِٛٚ Carbon derived compounds like diamond, graphite, and graphene are ٛ٘ ْٛ‫ فئْ اٌىشث‬،ْٛ‫وشث‬ٚ‫ذس‬١ٌٙ‫ ا‬ٍٝ‫خ رؼزّذ ػ‬١‫غ اٌىبئٕبد اٌس‬١ّ‫أْ خ‬ made of only one element, and the method of their production is ْٛ‫ رزى‬.‫بح‬١‫ء اٌس‬ٞ‫ خض‬ٛ٘ ‫بح إرا وبْ اٌّبء‬١‫ األعبط ػٕظش اٌس‬ٟ‫ف‬ different than the commercially available ceramics since the melting ِٓ ٓ١‫اٌدشاف‬ٚ ‫ذ‬١‫اٌدشاف‬ٚ ‫ْ ِثً اٌّبط‬ٛ‫اٌّشوجبد اٌّشزمخ ِٓ اٌىشث‬ temperature of carbon is very high. ‫فش‬ٛ‫ه اٌّز‬١ِ‫شا‬١‫ب ػٓ اٌغ‬ٙ‫مخ إٔزبخ‬٠‫رخزٍف ؽش‬ٚ ،‫ازذ فمؾ‬ٚ ‫ػٕظش‬.‫خ خذًا‬١ٌ‫ْ ػب‬ٛ‫بس اٌىشث‬ٙ‫ٔظشا ألْ دسخخ زشاسح أظ‬ ً ‫ًب‬٠‫ردبس‬ The carbon-based materials are very diverse; even though they are formed only of carbon, they can be very soft like graphite and very hard like diamond. This difference originates from the chemistry and ‫ب‬ٙٔ‫ اٌشغُ ِٓ أ‬ٍٝ‫خ؛ ػ‬٠‫ػخ ٌٍغب‬ٕٛ‫ْ ِز‬ٛ‫ اٌىشث‬ٍٝ‫اد اٌّؼزّذح ػ‬ٌّٛ‫ا‬ the organization of carbon atoms; they can be amorphous or highly ً‫ْ ٔبػّخ خذًا ِث‬ٛ‫ّىٓ أْ رى‬٠ ‫ب‬ٙٔ‫ إال أ‬،‫ْ فمؾ‬ٛ‫ْ ِٓ اٌىشث‬ٛ‫رزى‬ ordered crystalline forms. ‫بء‬١ّ١‫ٕشؤ ٘زا االخزالف ِٓ و‬٠.‫طٍجخ خذًا ِثً اٌّبط‬ٚ ‫ذ‬١‫اٌدشاف‬ ‫ أشىبي‬ٚ‫سح أ‬ٍٛ‫ش ِزج‬١‫ْ غ‬ٛ‫ّىٓ أْ رى‬٠ ‫ْ؛‬ٛ‫ُ رساد اٌىشث‬١‫رٕظ‬ٚ They have the ability to form molecules with a broad range of.‫ت‬١‫خ اٌزشر‬١ٌ‫خ ػب‬٠‫س‬ٍٛ‫ث‬ properties, and this makes carbon an indispensable element for the biomaterials field ،‫اسغ ِٓ اٌخظبئض‬ٚ ‫ئبد راد ٔطبق‬٠‫ٓ خض‬٠ٛ‫ رى‬ٍٝ‫ُ اٌمذسح ػ‬ٙ٠‫ٌذ‬ ‫خ‬٠ٛ١‫اد اٌس‬ٌّٛ‫ ِدبي ا‬ٟ‫ ػٕٗ ف‬ٕٝ‫ػٕظشا ال غ‬ ً ْٛ‫دؼً اٌىشث‬٠ ‫٘زا‬ٚ By : ENG.M.A.Hamoda  1. Pyrolytic Carbon PC ‫الكربون االنحاللي‬ Pyrolytic carbon is obtained by thermal decomposition of gaseous ٞ‫ك اٌزسًٍ اٌسشاس‬٠‫ ػٓ ؽش‬ٞ‫ْ اٌسشاس‬ٛ‫ اٌىشث‬ٍٝ‫ي ػ‬ٛ‫زُ اٌسظ‬٠ hydrocarbons at high temperatures. Making of the coal in the traditional ‫مخ‬٠‫ؼذ طٕغ اٌفسُ ثبٌطش‬٠.‫خ‬١ٌ‫خ ػٕذ دسخبد زشاسح ػب‬٠‫ٔبد اٌغبص‬ٛ‫وشث‬ٚ‫ذس‬١ٌٍٙ way is also a method of pyrolysis. ٞ‫ ؽشق االٔسالي اٌسشاس‬ٜ‫ؼًب إزذ‬٠‫خ أ‬٠‫ذ‬١ٍ‫اٌزم‬ Pyrolytic carbon has a structure similar to that of graphite In both the ‫ث‬١‫ ز‬،‫ذ‬١‫ اٌدشاف‬ٟ‫دح ف‬ٛ‫خ‬ٌّٛ‫خ ٌزٍه ا‬ٙ‫خ ِشبث‬١ٕ‫ ث‬ٍٝ‫ ػ‬ٌٟ‫ْ االٔسال‬ٛ‫ اٌىشث‬ٞٛ‫سز‬٠. carbons form hexagonals which constitute layers. These layers are ً ‫ظ ٘زٖ اٌطجمبد‬٠‫زُ رىذ‬٠.‫خ رشىً ؽجمبد‬١‫أشىبال عذاع‬ ْٛ‫رشىً وٍزب رساد اٌىشث‬ stacked on top of each other and held together by weaker interlayer.‫خ أػؼف‬١ٕ١‫اثؾ ث‬ٚ‫اعطخ س‬ٛ‫ب ِ ًؼب ث‬ٙ‫ؼ‬١ّ‫زُ رد‬٠ٚ ‫ب اٌجؼغ‬ٙ‫ق ثؼؼ‬ٛ‫ف‬ bonds. ‫اػطشاة اٌطجمبد ِّب‬ٚ ‫ ثبٔخفبع زدُ اٌطجمبد‬ٌٟ‫ْ االٔسال‬ٛ‫خزٍف اٌىشث‬٠ٚ Pyrolytic carbon differs by the lower size of the layers and the disorder ‫ ال‬،‫خ‬١ٌ‫د ؽجمبد ِثب‬ٛ‫خ‬ٚ َ‫ٔظشا ٌؼذ‬ ً.‫ب‬ٕٙ١‫ّب ث‬١‫ف‬ٚ ‫٘بد داخً اٌطجمبد‬ٛ‫ رش‬ٌٝ‫ إ‬ٞ‫ؤد‬٠ of the layers which lead to distortions within and between layers. Due ْٛ‫ّٕر اٌىشث‬٠ ‫٘زا‬ٚ ،‫ب اٌجؼغ‬ٙ‫ق ثؼؼ‬ٛ‫ اٌمض أْ رٕضٌك اٌطجمبد ف‬ٜٛ‫ّىٓ ٌم‬٠ to the lack of perfect layering, shear forces cannot slide layers past each.‫ذ‬١‫اٌّزبٔخ اٌّسسٕخ ِمبسٔخ ثبٌدشاف‬ٚ ‫ دسخخ اٌضخبج‬ٞ‫اٌسشاس‬ other, and this gives pyrolytic carbon the glassiness and improved durability compared to graphite. -100 ،‫ح اٌشذ‬ٛ‫ ل‬:ٍٟ٠ ‫ وّب‬ٟ٘ ٞ‫ْ اٌسشاس‬ٛ‫خ ٌٍىشث‬١‫ى‬١ٔ‫ىب‬١ٌّ‫اص ا‬ٛ‫ثؼغ اٌخ‬ 550-450 ‫ح اٌؼغؾ‬ٛ‫دب ثبسىبي؛ ل‬١ِ 400-300 ‫ح االٔثٕبء‬ٛ‫دبثبسىبي؛ ل‬١ِ 120 Some mechanical properties of pyrolytic carbon are the following:.‫دب ثبسىبي‬١‫ خ‬29-23 ‫ٔخ‬ٚ‫ِؼبًِ اٌّش‬ٚ ‫دب ثبسىبي؛‬١ِ tensile strength, 100–120 MPa; flexural strength 300–400 MPa; compressive strength 450–550 MPa; and the modulus of elasticity ‫( ِٓ خالي زشوخ أخضاء‬PC( ٞ‫ْ اٌسشاس‬ٛ‫ذ خظبئض أفالَ اٌىشث‬٠‫زُ رسذ‬٠ 23–29 GPa. ‫خ‬١ٍ‫ وٍّب صادد لبث‬.‫ب‬ٙ‫لذ رشعج‬ٚ ٟ‫ذ) ف‬١‫ (اٌدشاف‬ِٟ‫ اٌغطر اٌّزٕب‬ٍٝ‫ْ ػ‬ٛ‫اٌىشث‬..ً‫ أفؼ‬ٞ‫س‬ٍٛ‫وبْ االردبٖ اٌج‬ٚ ‫ساد أوجش‬ٍٛ‫ وٍّب وبْ زدُ اٌج‬،‫اٌسشوخ‬ The properties of pyrolytic carbon (PC) films are determined by the mobility of the carbon fragments on the growing surface (graphite) at the time of their deposition. The higher the mobility, the larger is the crystallite Lecture 7 size and the better is the crystallite orientation. By : ENG.M.A.Hamoda As a result of good crystallite alignment and high compaction, the P ‫ّىٓ أْ رظً وثبفخ‬٠ ،ٌٟ‫اٌؼغؾ اٌؼب‬ٚ ‫ذح‬١‫خ اٌد‬٠‫س‬ٍٛ‫دخ ٌٍّسبراح اٌج‬١‫ٔز‬ C can have densities as high as 2.22 g/cm3, which is close to that of ‫ذ‬١‫جخ ِٓ وثبفخ اٌدشاف‬٠‫ لش‬ٟ٘ٚ ،3ُ‫س‬/ُ‫ خ‬2.22 ٌٝ‫ٔبد إ‬ٛ‫ وشث‬ٌٟٛ‫اٌج‬ graphite (2.26 g/cm3 ‫ف‬ٚ‫ظ ِغ ظش‬ٛ‫ ثشىً ٍِس‬PC ‫رخزٍف وثبفخ‬.)3ُ‫س‬/ُ‫ خ‬2.26( The density of P C varies markedly with processing conditions including deposition temperature and gas pressures.The parallel ٞٛ‫ رسز‬.‫ؽ اٌغبص‬ٛ‫ػغ‬ٚ ‫ت‬١‫ رٌه دسخخ زشاسح اٌزشع‬ٟ‫اٌّؼبٌدخ ثّب ف‬ layers of the crystallites have crosslinks between them..‫ب‬ٕٙ١‫اثؾ ِزمبؽؼخ ث‬ٚ‫ س‬ٍٝ‫ساد ػ‬ٍٛ‫خ ِٓ اٌج‬٠‫اص‬ٛ‫اٌطجمبد اٌّز‬ If the crosslinking is minimal, it forms lubricating graphite, and the ٜٛ‫اٌّغز‬ٚ ،ُ١‫ذ رشس‬١‫شىً خشاف‬٠ ٗٔ‫ فئ‬،ٝٔ‫ زذٖ األد‬ٟ‫إرا وبْ اٌزشبثه ف‬ high level of crosslinking forms pyrolytic carbon. Graphite is stable ‫ذ ِسزمش رسذ‬١‫ اٌدشاف‬.ٞ‫ْ اٌسشاس‬ٛ‫شىً اٌىشث‬٠ ‫ ِٓ اٌزشبثه‬ٌٟ‫اٌؼب‬ under ambient temperature and pressure and can be converted into ‫ ِبط ػٕذ دسخخ‬ٌٝ‫ٍٗ إ‬٠ٛ‫ّىٓ رس‬٠ٚ ٓ١‫ط‬١‫اٌؼغؾ اٌّس‬ٚ ‫دسخخ اٌسشاسح‬ diamond at high temperature and pressure.General advantages of pyrolytic carbon are high strength, high wear resistance, and ‫ح‬ٛ‫ اٌم‬ٟ٘ ٞ‫ْ اٌسشاس‬ٛ‫ب اٌؼبِخ ٌٍىشث‬٠‫ اٌّضا‬.ٓ١‫ػغؾ ِشرفؼ‬ٚ ‫زشاسح‬ therefore durability, biocompatibility (initiation of no adverse ٞٛ١‫افك اٌس‬ٛ‫اٌز‬ٚ ،‫ اٌّزبٔخ‬ٌٟ‫ثبٌزب‬ٚ ،‫خ‬١ٌ‫ِخ اٌزآوً اٌؼب‬ٚ‫ِمب‬ٚ ،‫خ‬١ٌ‫اٌؼب‬ responses in the body), and hemocompatibility (no blood clotting, ‫افك اٌذَ (ػذَ رخثش‬ٛ‫ ر‬ٚ ،)ُ‫ اٌدغ‬ٟ‫خ ف‬١‫د اعزدبثبد ػىغ‬ٛ‫خ‬ٚ َ‫(ثذء ػذ‬ in other words, thromboresistance). In its applications in the ‫ ِدبي اٌطت‬ٟ‫مبرٗ ف‬١‫ رطج‬ٟ‫ ف‬.)‫ِخ اٌزخثش‬ٚ‫ ِمب‬،ٜ‫ثؼجبسح أخش‬ٚ ،َ‫اٌذ‬ biomedical field such as heart valves, small orthopedic joints ،)‫شح (األطبثغ‬١‫خ اٌظغ‬١ّ‫اٌّفبطً اٌؼظ‬ٚ ،‫ ِثً طّبِبد اٌمٍت‬ٞٛ١‫اٌس‬ (fingers), and spinal inserts, pyrolytic carbon generally is used as a َ‫ ثشىً ػب‬ٞ‫ْ اٌسشاس‬ٛ‫زُ اعزخذاَ اٌىشث‬٠ ،ٞ‫د اٌفمش‬ّٛ‫إدساج اٌؼ‬ٚ coating on implant materials prepared by pyrolysis of hydrocarbon vapor carried with a hydrocarbon carrier gas. In the case of heart ٞ‫ك االٔسالي اٌسشاس‬٠‫اد اٌضسع اٌّسؼشح ػٓ ؽش‬ِٛ ٍٝ‫وطالء ػ‬ valves, it is deposited in a fluidized bed on graphite shaped in the ‫ زبٌخ‬ٟ‫ف‬ٚ.ٟٔٛ‫وشث‬ٚ‫ذس‬١٘ ً‫ي ِغ غبص ٔبل‬ّٛ‫ْ اٌّس‬ٛ‫وشث‬ٚ‫ذس‬١ٌٙ‫ٌجخبس ا‬ form of the heart valve to render it inert, strong, light, and ً‫ شى‬ٍٝ‫ذ ػ‬١‫ اٌدشاف‬ٍٝ‫ؼخ ػ‬١ِّ ‫ ؽجمخ‬ٟ‫جٗ ف‬١‫زُ رشع‬٠ ،‫طّبِبد اٌمٍت‬ hemocompatible. ً.َ‫افك ِغ اٌذ‬ٛ‫ش ِز‬١‫غ‬ٚ ‫فًب‬١‫خف‬ٚ ‫ًب‬٠ٛ‫ل‬ٚ ‫خبِال‬ ٍٗ‫طّبَ اٌمٍت ٌدؼ‬ Lecture 7 By : ENG.M.A.Hamoda  Graphite Graphite exists as a layered material consisting of parallel layers of ‫خ‬١‫خ عذاع‬٠‫اص‬ٛ‫ْ ِٓ ؽجمبد ِز‬ٛ‫ذ وّبدح راد ؽجمبد رزى‬١‫خذ اٌدشاف‬ٛ٠ hexagonal The layers are bonded by weak linkages (Fig. 6.2). The a = ٟ٘ ‫زذح‬ٌٛ‫خ ا‬١ٍ‫ أثؼبد خ‬.)6.2 ً‫فخ (اٌشى‬١‫اثؾ ػؼ‬ٚ‫رشرجؾ اٌطجمبد ثش‬ٚ unit cell dimensions are a = b = 2.456 Å and c = 6.694 Å. The ٟ‫ْ ف‬ٛ‫اٌىشث‬-ْٛ‫ي ساثطخ اٌىشث‬ٛ‫جٍغ ؽ‬٠c = 6.694 Å. ٚb = 2.456 Å carbon-carbon bond length in the layer is 1.418 Å, while the 3.347( ‫ش‬١‫ٓ اٌطجمبد أوجش ثىث‬١‫ٓ أْ اٌزجبػذ ث‬١‫ ز‬ٟ‫ ف‬،Å 1.418 ‫اٌطجمخ‬ interlayer spacing is significantly larger (3.347 Å(. Å). Graphite does not bear any net charges because in its natural form, ‫خذ‬ٛ‫ ال ر‬ٟ‫ؼ‬١‫ شىٍٗ اٌطج‬ٟ‫خ ألٔٗ ف‬١‫ شسٕبد طبف‬ٞ‫ذ أ‬١‫سًّ اٌدشاف‬٠ ‫ال‬ no reactive ions or groups exist within the hexagonal layers.Graphite ‫ذ‬١‫ّىٓ ٌٍدشاف‬٠.‫خ‬١‫ػبد ِزفبػٍخ داخً اٌطجمبد اٌسذاس‬ّٛ‫ ِد‬ٚ‫ٔبد أ‬ٛ٠‫أ‬ can take in various atoms, molecules, metal complexes, and salts ٓ١‫أِالذ ِخزٍفخ ث‬ٚ ‫خ ِخزٍفخ‬١ٔ‫ِدّؼبد ِؼذ‬ٚ ‫ئبد‬٠‫خض‬ٚ ‫ؤخز رساد‬٠ ْ‫أ‬ between the layers to form “graphite intercalation compounds.” ‫ذ‬١‫ً اٌدشاف‬٠‫ؼًب رؼذ‬٠‫ّىٓ أ‬٠."‫ذ‬١‫ٓ "ِشوجبد إلسبَ اٌدشاف‬٠ٛ‫اٌطجمبد ٌزى‬ ‫ذ اٌّمسّخ‬١‫ِشوجبد اٌدشاف‬ٚ ،)‫ذ‬١‫ذ اٌدشاف‬١‫ٓ (أوس‬١‫ذ اٌدشاف‬١‫ٓ أوس‬٠ٛ‫ٌزى‬ Graphite can also be modified to form graphene oxide (graphite ‫زُ ػشع ثؼغ خظبئض‬٠EG). ( ‫عغ‬ٌّٛ‫ذ ا‬١‫اٌدشاف‬ٚ ،GICs)( oxide), graphite intercalated compounds (GICs), and expanded ٗ‫ٔظشا ٌخظبئظ‬ ً ،‫ذ‬١‫ّىٓ اعزخذاَ اٌدشاف‬٠.6.1 ‫ي‬ٚ‫ اٌدذ‬ٟ‫ذ ف‬١‫اٌدشاف‬ graphite (EG). Some properties of graphite are presented in Table ٞٛ١‫ ِدبي اٌطت اٌس‬ٟ‫مبد ف‬١‫ذ ِٓ اٌزطج‬٠‫ اٌؼذ‬ٟ‫ ف‬،‫خ‬٠‫٘ش‬ٛ‫اٌد‬ 6.1.Graphite, due to its intrinsic properties, can be used in many applications in the biomedical field. Lecture By : ENG.M.A.Hamoda Thrombosis on prostheses coated with graphite was studied in the 1960s, and hey were found to be non-thrombogenic, and it ٟ‫ذ ف‬١‫خ ثبٌدشاف‬١ٍ‫خ اٌّط‬١‫ األؽشاف االططٕبػ‬ٟ‫رّذ دساسخ ردٍؾ اٌذَ ف‬ was also found that graphite-based endoprostheses were generally nontoxic and produced no immunological reactions. ‫ؼًب أْ األؽشاف‬٠‫خذ أ‬ٚ ‫ وّب‬،‫ش ِسججخ ٌٍزخثش‬١‫ب غ‬ٙٔ‫ٓ أ‬١‫رج‬ٚ ،‫بد‬١ٕ١‫اٌسز‬ When treated with glow discharge, its nonreactivity changes; ‫ٌُ رٕزح‬ٚ َ‫ش سبِخ ثشىً ػب‬١‫ذ وبٔذ غ‬١‫ اٌدشاف‬ٍٝ‫خ اٌمبئّخ ػ‬١‫االططٕبػ‬ the compound becomes hydrophilic, and this makes the surface ‫ش ػذَ رفبػٍٗ؛‬١‫زغ‬٠ ،‫٘ح‬ٌٛ‫غ ا‬٠‫ ػٕذ اٌزؼبًِ ِغ اٌزفش‬.‫خ‬١‫ رفبػالد ِٕبػ‬ٞ‫أ‬ more reactive and favorable for protein adsorption.The ً ‫ِالئ ًّب‬ٚ ‫رفبػال‬ ‫دؼً اٌغطر أوثش‬٠ ‫٘زا‬ٚ ،‫ظجر اٌّشوت ِسجًب ٌٍّبء‬٠ hexagonal crystal structure of graphite formed by the sp2 σ ِٓ ‫ٔخ‬ٛ‫ذ اٌّزى‬١‫خ ٌٍدشاف‬١‫خ اٌغذاع‬٠‫س‬ٍٛ‫خ اٌج‬١ٕ‫ إْ اٌج‬.ٓ١‫ر‬ٚ‫الِزظبص اٌجش‬ bonds is actually graphene layers or carbon layer planes, bonded ‫ ِشرجطخ‬،ْٛ‫بد ؽجمخ وشث‬٠ٛ‫ ِغز‬ٚ‫ٓ أ‬١‫الغ ؽجمبد خشاف‬ٌٛ‫ ا‬ٟ‫ ف‬ٟ٘σ ‫اثؾ‬ٚ‫س‬ together in between the planes by π bonding. The most common crystal form of graphite consists of stacks in the order ABABAB ٞ‫س‬ٍٛ‫ْ اٌشىً اٌج‬ٛ‫زى‬٠π. ‫اثؾ‬ٚ‫اعطخ س‬ٛ‫بد ث‬٠ٛ‫ٓ اٌّغز‬١‫ب اٌجؼغ ث‬ٙ‫ثجؼؼ‬ ABABAB. ‫ت‬١‫اَ ثبٌزشر‬ٛ‫ذ ِٓ أو‬١‫ػب ٌٍدشاف‬ ً ٛ١‫األوثش ش‬ The rhombohedral form of graphite has a stacking sequence of ABCABC ِٓ ‫ رسٍسً رشاص‬ٍٝ‫ذ ػ‬١‫ ٌٍدشاف‬ٟٕ١‫ اٌشىً اٌّؼ‬ٞٛ‫سز‬٠ ABCABC but constitutes only a minor fraction of well- ،‫ة‬ٛ١‫اٌؼ‬ٚ.‫ذًا‬١‫س خ‬ٍٛ‫ذ اٌّزج‬١‫ش ِٓ اٌدشاف‬١‫ خضء طغ‬ٜٛ‫شىً س‬٠ ‫ٌىٕٗ ال‬ٚ crystallized graphites.The defects, particularly vacancies, are the ٍٝ‫ رؤثش ػ‬ٟ‫خ اٌز‬١‫س‬١‫مخ اٌشئ‬١‫خ اٌذل‬١ٍ‫ى‬١ٌٙ‫ضح ا‬١ٌّ‫ ا‬ٟ٘ ،‫اغش‬ٛ‫خبطخ اٌش‬ٚ main microstructural feature that affect the strength of brittle materials such as graphite the most. Under the influence of the ٚ‫بد اٌشذ أ‬ٙ‫ش إخ‬١‫ رسذ رؤث‬.‫ش٘ب‬١‫ذ أوثش ِٓ غ‬١‫شخ ِثً اٌدشاف‬ٌٙ‫اد ا‬ٌّٛ‫ح ا‬ٛ‫ل‬ applied tensile or shear stress, microscopic defects grow and ٓ‫ اٌفشً ػ‬ٌٝ‫خ إ‬٠‫ب‬ٌٕٙ‫ ا‬ٟ‫ ف‬ٞ‫رؤد‬ٚ ‫خ‬٠‫ش‬ٙ‫ة اٌّد‬ٛ١‫ اٌؼ‬ّٕٛ‫ ر‬،‫اٌمض اٌّطجك‬ eventually lead to the failure by fracture. This, in addition to ‫ذ‬١‫دؼً اٌدشاف‬٠ ،‫ اٌمض‬ٜٛ‫ اٌؼؼف أِبَ ل‬ٌٝ‫ ثبإلػبفخ إ‬،‫ ٘زا‬.‫ك اٌىسش‬٠‫ؽش‬ weakness against shear forces, makes graphite mechanically.‫مبد‬١‫ذ ِٓ اٌزطج‬٠‫ اٌؼذ‬ٟ‫جًب ف‬١‫شىً ػ‬٠ ‫ ِّب‬،‫ًب‬١‫ى‬١ٔ‫ىب‬١ِ ‫٘شًب‬ fragile, which constitutes a disadvantage in many applications. Lecture 7 By : ENG.M.A.Hamoda Lecture 7 By : ENG.M.A.Hamoda  Active Charcoal (Activated Carbon) )‫ْ إٌّشؾ‬ٛ‫اٌفسُ إٌشؾ (اٌىشث‬ ctivated carbon is an amorphous solid with very high porosity and a very large internal surface area. It has the capability to adsorb molecules from both the liquid and gas phase and is therefore used in purification and cleaning ‫خ خذًا‬١ٌ‫خ ػب‬١ِ‫سح راد ِسب‬ٍٛ‫ش ِزج‬١‫ْ إٌّشؾ ػجبسح ػٓ ِبدح طٍجخ غ‬ٛ‫اٌىشث‬ processes including the biomedical field. It can be produced from many ِٓ ‫ئبد‬٠‫ اِزظبص اٌدض‬ٍٝ‫ٗ اٌمذسح ػ‬٠‫ ٌذ‬.‫شح خذًا‬١‫خ وج‬١ٍ‫ِسبزخ سطر داخ‬ٚ organic natural carbon-based materials such as wood, nutshells (coconut, ٟ‫ف ثّب ف‬١‫اٌزٕظ‬ٚ ‫خ‬١‫بد اٌزٕم‬١ٍّ‫ ػ‬ٟ‫غزخذَ ف‬٠ ٌٟ‫ثبٌزب‬ٚ ،ٞ‫اٌغبص‬ٚ ً‫س اٌغبئ‬ٛ‫اٌط‬ pecan, etc.), and lignite coal. ‫خ راد‬٠ٛ‫اد اٌؼؼ‬ٌّٛ‫ذ ِٓ ا‬٠‫ّىٓ إٔزبخٗ ِٓ اٌؼذ‬٠.ٞٛ١‫رٌه ِدبي اٌطت اٌس‬ ،ْ‫ اٌجمب‬،‫ٕذ‬ٌٙ‫ص ا‬ٛ‫ص (خ‬ٛ‫س اٌد‬ٛ‫لش‬ٚ ،‫ ِثً اٌخشت‬ٟ‫ؼ‬١‫ اٌطج‬ٟٔٛ‫األعبط اٌىشث‬ The process is basically activation of charcoal, and it is done by heating it to 600–1200 °C in the presence of oxidizing gases such as CO2, steam, or air,.‫ذ‬١ٕ‫د‬١ٌٍ‫فسُ ا‬ٚ ،)‫إٌخ‬ or it is impregnated with chemicals such as acids (phosphoric acid) or bases (potassium hydroxide), or salts (zinc chloride), and then heated to 450–900 ‫ دسخخ زشاسح‬ٌٝ‫ٕٗ إ‬١‫ك رسخ‬٠‫رزُ ػٓ ؽش‬ٚ ،ُ‫ؾ اٌفس‬١‫ األسبط رٕش‬ٟ‫ ف‬ٟ٘ ‫خ‬١ٍّ‫اٌؼ‬ °C. Each approach has its advantages and disadvantages. Activated charcoal ْٛ‫ذ اٌىشث‬١‫ أوس‬ٟٔ‫د اٌغبصاد اٌّؤوسذح ِثً ثب‬ٛ‫خ‬ٚ ٟ‫خ ف‬٠ٛ‫ دسخخ ِئ‬1200-600 can be processed into powder, granular, and pellet forms. On the average, the ‫خ ِثً األزّبع (زّغ‬١‫بئ‬١ّ١‫اد و‬ّٛ‫جٗ ث‬٠‫زُ رشش‬٠ ٚ‫ أ‬،‫اء‬ٌٛٙ‫ ا‬ٚ‫ اٌجخبس أ‬ٚ‫أ‬ specific surface area (SSA) of the material can range from 500 to 1400 m2 /g ‫ذ‬٠‫س‬ٍٛ‫ األِالذ (و‬ٚ‫ أ‬،)َٛ١‫ربس‬ٛ‫ذ اٌج‬١‫وس‬ٚ‫ذس‬١٘( ‫اػذ‬ٛ‫ اٌم‬ٚ‫ه) أ‬٠‫س‬ٛ‫سف‬ٛ‫اٌف‬ ٖ‫ب‬٠‫ح ٌٗ ِضا‬ٙٔ ً‫ و‬.‫خ‬٠ٛ‫ دسخخ ِئ‬900-450 ٌٝ‫ب إ‬ٕٙ١‫زُ رسخ‬٠ ُ‫ ث‬،)‫اٌضٔه‬ The total pore volume is about 0.71 cm3/g. The complex interior of activated ٟ‫ ف‬.‫بد‬٠‫وش‬ٚ ‫جبد‬١‫زج‬ٚ ‫ق‬ٛ‫ أشىبي ِسس‬ٌٝ‫ّىٓ ِؼبٌدخ اٌفسُ إٌّشؾ إ‬٠.ٗ‫ث‬ٛ١‫ػ‬ٚ charcoal consists of pores with different diameters: micropores (diameters 50 nm). ُ‫خ‬/2َ 1400 Micropores constitute the major portion of the structure of the A C. ُ‫ اٌّؼمذ ٌٍفس‬ٍٟ‫ْ اٌدضء اٌذاخ‬ٛ‫زى‬٠.ُ‫ خ‬/ 3 ُ‫ س‬0.71 ٌٟ‫ا‬ٛ‫ زدُ اٌّسبَ ز‬ٌٟ‫جٍغ إخّب‬٠ Of the various activated carbon materials, fibers have the narrowest َ‫ اٌّغب‬،)‫ِزش‬ٛٔ‫ ٔب‬2 ِٓ ً‫شح (ألطبس أل‬١‫ اٌّغبَ اٌظغ‬:‫إٌّشؾ ِٓ ِغبَ ثؤلطبس ِخزٍفخ‬ distribution of pore sizes and nanopores. The dominance of the carbon ً‫ رشى‬.)‫ِزش‬ٛٔ‫ ٔب‬50 ِٓ ‫شح (ألطبس أوجش‬١‫اٌّغبَ اٌىج‬ٚ ،)‫ِزش‬ٛٔ‫ ٔب‬50-2 ‫عطخ (ألطبس‬ٛ‫اٌّز‬ nanopores in the fibers makes them attractive for various applications. ،‫ْ إٌّشؾ اٌّخزٍفخ‬ٛ‫اد اٌىشث‬ِٛ ٓ١‫ِٓ ث‬AC. ً‫ى‬١٘ ِٓ ‫شح اٌدضء األوجش‬١‫اٌّغبَ اٌظغ‬ ‫خ‬٠ٛٔ‫ّٕخ اٌّغبَ إٌب‬١٘ ْ‫ إ‬.‫خ‬٠ٛٔ‫اٌّغبَ إٌب‬ٚ َ‫ك ألزدبَ اٌّغب‬١‫غ األػ‬٠‫ص‬ٛ‫بف ثبٌز‬١ٌ‫رزّزغ األ‬.‫مبد‬١‫ب خزاثخ ٌّخزٍف اٌزطج‬ٍٙ‫بف ردؼ‬١ٌ‫ األ‬ٟ‫خ ف‬١ٔٛ‫اٌىشث‬ Lecture 7 By : ENG.M.A.Hamoda  Graphene ٓ١‫اٌدشاف‬ Graphene has excellent mechanical, electrical, thermal, and optical َ‫ ػب‬ٝ‫ زز‬.‫خ ِّزبصح‬٠‫ثظش‬ٚ ‫خ‬٠‫زشاس‬ٚ ‫خ‬١‫شثبئ‬ٙ‫و‬ٚ ‫خ‬١‫ى‬١ٔ‫ىب‬١ِ ‫ٓ ثخظبئض‬١‫زّزغ اٌدشاف‬٠ properties. Until 2004, graphene was considered to be ِٓ ٌٟ‫ثبٌزب‬ٚ ‫خ‬٠‫خ اٌسشاس‬١‫ى‬١ِ‫ٕب‬٠‫خ اٌذ‬١‫ش ِغزمش ِٓ إٌبز‬١‫ؼزجش غ‬٠ ٓ١‫ وبْ اٌدشاف‬،2004 thermodynamically unstable and hence theoretically impossible to ‫ صاد‬،ٗ‫ٓ اٌمبئُ ثزار‬١‫ٌىٓ ثؼذ اوزشبف اٌدشاف‬ٚ ،‫ زبٌخ زشح‬ٟ‫دٖ ف‬ٛ‫خ‬ٚ ‫ًب‬٠‫ً ٔظش‬١‫اٌّغزس‬ exist in free state, but after the discovery of free-standing graphene,.‫ش‬١‫اد ثٗ ثشىً وج‬ٌّٛ‫ا٘زّبَ ػٍّبء ا‬ interest of material scientists in it grew exponentially. Obviously these are cases when the graphene and derivatives are used ٗ‫ِشزمبر‬ٚ ٓ١‫ب اعزخذاَ اٌدشاف‬ٙ١‫زُ ف‬٠ ٟ‫ اٌسبالد اٌز‬ٟ٘ ٖ‫اػر أْ ٘ز‬ٌٛ‫ِٓ ا‬ as small particles or flakes rather than as a coat on or as a component ْٛ‫ وّى‬ٚ‫ق اٌغشعخ أ‬ٛ‫ب وطجمخ ف‬ِٙ‫شح ثذالً ِٓ اعزخذا‬١‫ سلبئك طغ‬ٚ‫ئبد أ‬٠‫ودض‬ in an implant. Most studies show that the toxic effect of the fillers is ٟ‫ب ف‬ٙ‫ٕخفغ ػٕذ دِد‬٠ ‫اد‬ٛ‫ش اٌسبَ ٌٍسش‬١‫ش ِؼظُ اٌذساسبد أْ اٌزؤث‬ٙ‫ رظ‬.‫ب‬ٙ١‫ف‬ reduced when incorporated in biomaterials, due to decrease of direct َ‫ػذ‬ٚ ‫خ اٌّجبششح‬١‫خ‬ٌٛٛ١‫رٌه ثغجت أخفبع اٌزفبػالد اٌج‬ٚ ،‫خ‬٠ٛ١‫اد اٌس‬ٌّٛ‫ا‬ biological interactions and inability of the cells to endocytose these ‫ًب‬١‫ى‬١ٔ‫ىب‬١ِ ‫ اٌزؼشع ٌٍزٍف‬ٚ‫ئبد أ‬٠‫زٖ اٌدض‬ٌٙ ٍٞٛ‫ االٌزمبَ اٌخ‬ٍٝ‫ب ػ‬٠‫لذسح اٌخال‬ particles or get damaged mechanically by their sharp edges. On the ‫خ اٌىبس٘خ ٌٍّبء‬١ٔٛ‫اد اٌىشث‬ٌّٛ‫ فئْ ا‬،‫ اٌؼىظ ِٓ رٌه‬ٍٝ‫ ػ‬.‫ب اٌسبدح‬ٙ‫اف‬ٛ‫ثغجت ز‬ contrary, hydrophobic carbon materials decrease adhesion of blood ‫ؾ‬١‫رمًٍ ِٓ رٕش‬ٚ ،ٓ١ِٛ‫رؼضص اِزظبص األٌج‬ٚ ،َ‫رمًٍ ِٓ اٌزظبق ػٕبطش اٌذ‬ elements, favor albumin adsorption, and decrease platelet activation..‫ش ِغججخ ٌٍزخثش‬١‫ب غ‬ٙٔ‫ أ‬ٚ‫جذ‬٠ ‫دخ ٌزٌه‬١‫ٔز‬ٚ.‫خ‬٠ِٛ‫اٌظفبئر اٌذ‬ As a result they appear to be non-thrombogenic.. Lecture 7 By : ENG.M.A.Hamoda  Graphene ٓ١‫اٌدشاف‬ Lecture 7 By : ENG.M.A.Hamoda  Carbon Nanotubes ‫خ‬٠ٛٔ‫ْ إٌب‬ٛ‫ت اٌىشث‬١‫أٔبث‬ The mechanical properties of this material are extremely high. The ٟ‫ اٌّمطغ اٌؼشػ‬ٞٛ‫سز‬٠.‫خ‬٠‫خ ٌٍغب‬١ٌ‫اد ػب‬ٌّٛ‫زٖ ا‬ٌٙ ‫خ‬١‫ى‬١ٔ‫ىب‬١ٌّ‫اص ا‬ٛ‫اٌخ‬ cross-section of the walls of MWNTs have an elastic modulus ‫ح شذ رجٍغ‬ٛ‫ل‬ٚTPa 1 ِٓ ‫مزشة‬٠ ْ‫ ِؼبًِ ِش‬ٍٝ‫ػ‬MWNTs ْ‫ٌدذسا‬ approaching 1 TPa and a tensile strength of 100 GPa. These values.‫خ‬١‫بف طٕبػ‬١ٌ‫ أ‬ٞ‫ ػشش ِشاد ِٓ أ‬ٌٟ‫ا‬ٛ‫ ثس‬ٍٝ‫ُ أػ‬١‫٘زٖ اٌم‬GPa. 100 are about ten times higher than any industrial fiber. Deng et al..ْٚ‫آخش‬ٚ ‫ٕغ‬٠‫د‬ Their semiconductive behavior varies in the temperature range 300– 75.4 K. The electrical resistivity of individual CNTs was found to be as.ٓ‫ وٍف‬75.4-300 ‫ ٔطبق دسخخ اٌسشاسح‬ٟ‫طً ف‬ٌّٛ‫ب شجٗ ا‬ٙ‫و‬ٍٛ‫خزٍف ع‬٠ low as 10−6 Ω cm.The basic properties of nanotubes such as a very ‫خ‬٠‫خ اٌفشد‬١ٔٛ‫خ اٌىشث‬٠ٛٔ‫ت إٌب‬١‫خ ٌألٔبث‬١‫شثبئ‬ٙ‫ِخ اٌى‬ٚ‫خذ أْ اٌّمب‬ٚ ‫لذ‬ٚ high longitudinal flexibility factor, a Young’s modulus similar to that of ‫خ‬٠ٛٔ‫ت إٌب‬١‫خ ٌألٔبث‬١‫ اٌخظبئض األعبع‬.ُ‫ع‬Ω 6−10 ٌٝ‫ِٕخفؼخ رظً إ‬ diamond, a high mechanical resistance to stretching (several hundred ‫ٔح ِشبثٗ ِمبسٔخ‬ٛ٠ ًِ‫ِؼب‬ٚ ،‫ خذًا‬ٌٟ‫خ اٌؼب‬١ٌٛ‫ٔخ اٌط‬ٚ‫ِثً ػبًِ اٌّش‬ times greater than the most resilient steel), the highest heat ِٓ ‫خ ٌٍزّذد (أوجش ثؼذح ِئبد ِٓ اٌّشاد‬١ٌ‫خ ػب‬١‫ى‬١ٔ‫ىب‬١ِ ‫ِخ‬ٚ‫ِمب‬ٚ ،‫ثبٌّبط‬ conductivity of all known materials, a very high length-to-diameter ،‫فخ‬ٚ‫اد اٌّؼش‬ٌّٛ‫غ ا‬١ّ‫خ ٌد‬٠‫خ زشاس‬١ٍ‫ط‬ِٛ ٍٝ‫أػ‬ٚ ،)‫ٔخ‬ٚ‫الر األوثش ِش‬ٛ‫اٌف‬ ratio, and a large surface area make CNT useful for many applications CNT ِٓ ً‫شح ردؼ‬١‫ِغبزخ عطر وج‬ٚ ،‫خ خذًا‬١ٌ‫ لطش ػب‬ٌٝ‫ي إ‬ٛ‫ٔغجخ ؽ‬ٚ in the biomedical field, too.CNTs are considered for use as biosensor ‫ت‬١‫ رؼزجش األٔبث‬.‫ؼًب‬٠‫ أ‬ٞٛ١‫ ِدبي اٌطت اٌس‬ٟ‫مبد ف‬١‫ذ ِٓ اٌزطج‬٠‫ ٌٍؼذ‬.‫ذًا‬١‫ِف‬ components and medical device parts because their dimensions and ‫خ‬٠ٛ١‫ضح اعزشؼبس ز‬ٙ‫ٔبد أخ‬ٛ‫خ لبثٍخ ٌالعزخذاَ وّى‬١ٔٛ‫خ اٌىشث‬٠ٛٔ‫إٌب‬ chemistry are quite suitable to work with biomole cules such as nucleic ‫ب ِٕبعجخ رّب ًِب ٌٍؼًّ ِغ‬ٙ‫بئ‬١ّ١‫و‬ٚ ‫خ ألْ أثؼبد٘ب‬١‫ضح اٌطج‬ٙ‫أخضاء ِٓ األخ‬ٚ acids (DNA, RNA) and proteins. The impetus behind their use is (i) RNA) ،DNA( ‫خ‬٠ٌٕٚٛ‫خ ِثً األزّبع ا‬٠ٛ١‫ئبد اٌس‬٠‫زذاد اٌدض‬ٚ large surface area and (ii) possibility for chemical modification and ‫شح‬١‫خ وج‬١‫) ِسبزخ سطس‬1( ٛ٘ ‫ب‬ِٙ‫ساء اسزخذا‬ٚ ‫ اٌذافغ‬.‫ٕبد‬١‫ر‬ٚ‫اٌجش‬ٚ (iii) for creating ordered structures that can be “read” easily. CNTs also ٓ‫ّى‬٠ ‫بوً ِشرجخ‬١٘ ‫) إٔشبء‬3(ٚ ٟ‫بئ‬١ّ١‫ً اٌى‬٠‫خ اٌزؼذ‬١ٔ‫) إِىب‬2(ٚ allow fluorescent and photoacoustic imaging and are very useful in ‫ش‬٠ٛ‫ؼًب ثبٌزظ‬٠‫خ أ‬١ٔٛ‫خ اٌىشث‬٠ٛٔ‫ت إٌب‬١‫ رسّر األٔبث‬.‫ٌخ‬ٛٙ‫ب" ثس‬ٙ‫"لشاءر‬ localized therapy via exposure to near-infrared radiation. ِٓ ٟ‫ػؼ‬ٌّٛ‫ اٌؼالج ا‬ٟ‫ذح خذًا ف‬١‫ ِف‬ٟ٘ٚ ٟ‫ر‬ٛ‫ اٌظ‬ٟ‫ئ‬ٛ‫اٌؼ‬ٚ ٞ‫س‬ٍٛ‫اٌف‬.‫جخ‬٠‫خالي اٌزؼشع ٌألشؼخ رسذ اٌسّشاء اٌمش‬ Lecture 7 By : ENG.M.A.Hamoda  Carbon Nanotubes ‫خ‬٠ٛٔ‫ْ إٌب‬ٛ‫ت اٌىشث‬١‫أٔبث‬ Lecture 7 By : ENG.M.A.Hamoda  Carbon Products as Coating Materials ‫اد ؽالء‬ّٛ‫ْ و‬ٛ‫ِٕزدبد اٌىشث‬ The fate of a biomaterial is determined by its reaction with the ‫ُؼشف‬٠.‫خ‬١‫خ‬ٌٛٛ١‫ئخ اٌج‬١‫ب ِغ اٌج‬ٍٙ‫خ ِٓ خالي رفبػ‬٠ٛ١‫ش اٌّبدح اٌس‬١‫ذ ِظ‬٠‫زُ رسذ‬٠ biological environment. Amorphous carbon and diamond-like carbon ‫خ‬١‫اد غشبئ‬ّٛ‫و‬DLC) ( ‫ٗ ثبألٌّبط‬١‫ْ اٌشج‬ٛ‫اٌىشث‬ٚ ‫س‬ٍٛ‫ش اٌّزج‬١‫ْ غ‬ٛ‫اٌىشث‬ (DLC) are known as bioinert film materials causing no toxic reactions ‫ إْ اٌظالثخ‬.ٟ‫ اٌىبئٓ اٌس‬ٟ‫ رفبػالد سبِخ ف‬ٞ‫ال رسجت أ‬ٚ ‫ًب‬١‫خ‬ٌٛٛ١‫خبٍِخ ث‬ in the living organism. The hardness, low coefficient of friction, high ٞٛ١‫اٌطبثغ اٌس‬ٚ ً‫اٌزآو‬ٚ ً‫خ ٌٍزآو‬١ٌ‫ِخ اٌؼب‬ٚ‫اٌّمب‬ٚ ‫ِؼبًِ االززىبن إٌّخفغ‬ٚ resistance to wear and corrosion, and the bioinert character of carbon ‫خ‬١‫خ ٌٍضساػبد اٌطج‬١ٌ‫خ ِثب‬١‫ت سطس‬١‫اد رشط‬ِٛ ‫ب‬ٍٙ‫خ ردؼ‬١ٔٛ‫خ اٌىشث‬١‫ٌألغش‬ films make them ideal surface finish materials for biomedical implants ‫ اٌؼذسبد‬ٚ‫ت اٌظشف أ‬١‫ أٔبث‬ٚ‫ اٌمسطشح أ‬ٚ‫خ ِثً طّبِبد اٌمٍت أ‬٠ٛ١‫اٌس‬ like heart valves , catheters, drainage tubes or polymer contact lenses. ٌٗٚ ‫س‬ٍٛ‫ش ِزج‬١‫ذسج غ‬ِٙ ْٛ‫ػجبسح ػٓ وشث‬DLC.‫خ‬٠‫ّش‬١ٌٛ‫اٌالطمخ اٌج‬ DLC is an amorphous hydrogenated carbon and has excellent ‫ش‬١‫ب غ‬ٙ‫ؼز‬١‫ٔظشا ٌطج‬ً.‫خ ِّزبصح‬١‫خ‬ٌٛٛ١‫ث‬ٚ ‫خ‬١‫اززىبو‬ٚ ‫خ‬١‫ى‬١ٔ‫ىب‬١ِ ‫خظبئض‬ mechanical, tribological, and biological properties. Due to it Co ٚV ٚW ٚO ٚN ٚF ٚSi ً‫ ِث‬،‫ّىٓ إػبفخ ثؼغ اٌؼٕبطش‬٠ ،‫سح‬ٍٛ‫اٌّزج‬ amorphous nature, some elements, such as Si, F, N, O, W, V, Co, Mo, ‫ضح االرظبي‬ٙ‫ أخ‬ٟ‫ف‬DLC َ‫ُفؼً اعزخذا‬٠ ‫ غبٌجًب ِب‬.ً‫ى‬١ٌٙ‫ ا‬ٌٝ‫إ‬Ti ٚMo ٚ and Ti can be added into the structure. DLC is often preferred for use ٗ‫خظبئظ‬ٚ َ‫افمٗ اٌّّزبص ِغ اٌذ‬ٛ‫ٔظشا ٌز‬ ً )‫طّبِبد اٌمٍت‬ٚ ‫ثبٌذَ (اٌذػبِبد‬ in blood-contacting devices (stents and heart valves) because of its ‫ اٌّفبطً اٌسبٍِخ ثغجت‬ٟ‫ؼًب ف‬٠‫أ‬ٚ ،‫ي‬ّٛ‫اٌخ‬ٚ ‫ِخ‬ٛ‫إٌؼ‬ٚ ،‫اٌّؼبدح ٌٍزخثش‬ excellent blood compatibility and antithrombogenic properties, ٌٝ‫طّبِبد اٌمٍت إ‬ٚ ٟ‫بْ اٌزبخ‬٠‫ دػبِبد اٌشش‬ٞ‫ رؤد‬.‫خ‬١ٌ‫ِخ اٌزآوً اٌؼب‬ٚ‫ِمب‬ smoothness, and inertness and also in load-bearing joints because of ‫خ لذ‬١ٔ‫ٔبد ِؼذ‬ٛ٠‫وزٌه إؽالق أ‬ٚ َ‫ب ٌٍذ‬ٙ‫خ أثٕبء ِالِغز‬٠ِٛ‫ؾ اٌظفبئر اٌذ‬١‫رٕش‬ high wear resistance. Coronary artery stents and heart valves lead to َ‫ض ردٍؾ اٌذ‬١‫ رسف‬ٟ‫ّخ ف‬ِٙ ًِ‫ا‬ٛ‫ ٘زٖ ػ‬.ُ٠‫ؾ اإلٔض‬١‫ رثج‬ٌٝ‫ إ‬ٞ‫رؤد‬ platelet activation during contact with blood and also release metallic ions which might lead to enzyme inhibition. These are important factors in triggering thrombosis Lecture 7 By : ENG.M.A.Hamoda  Carbon Products as Coating Materials ‫اد ؽالء‬ّٛ‫ْ و‬ٛ‫ِٕزدبد اٌىشث‬ Carbon coating of metallic stents and heart valves has been suggested ٖ‫ز‬ٌٙ ‫طّبِبد اٌمٍت وؼالج‬ٚ ‫خ‬١ٔ‫ْ ٌٍذػبِبد اٌّؼذ‬ٛ‫لذ رُ الزشاذ ؽالء اٌىشث‬ٚ as a remedy for these situations , and DLC-coated artificial heart valves DLC ‫اٌذػبِبد اٌّغٍفخ ثـ‬ٚ ‫خ‬١‫ وّب أْ طّبِبد اٌمٍت االططٕبػ‬،‫اٌسبالد‬ and stents are already commercially available (Fig. 6.6). ne healing ٚ‫ أ‬،َ‫طً ٌٍؼظب‬ِٛ ‫ٔظشا ألْ اٌؼالج‬ ً.)6.6 ً‫ًب ثبٌفؼً (اٌشى‬٠‫ِزبزخ ردبس‬ being osteoconductive, or better yet, osteoinductive is an important ‫ذ‬١‫ضح اٌزثج‬ٙ‫ّخ ألخ‬ِٙ ‫خ‬١‫ خبط‬ٛ٘ ّٟ‫ض اٌؼظ‬١‫ فئْ اٌزسف‬،‫األفؼً ِٓ رٌه‬ property of the fixation devices and implants. Pyrolytic carbon and ْ‫ ِسفضا‬ٟ‫ْ اٌضخبخ‬ٛ‫اٌىشث‬ٚ ٞ‫ْ اٌسشاس‬ٛ‫ ٌمذ ثجذ أْ اٌىشث‬.‫ػبد‬ٚ‫اٌّضس‬ٚ glassy carbon have been shown to be osteoinductive, even though they ‫ِؼبًِ االززىبن‬.‫ًب‬١‫ى‬١ٔ‫ىب‬١ِ ٓ٠‫ش ِغزمش‬١‫ّب غ‬ٙٔ‫ اٌشغُ ِٓ أ‬ٍٝ‫ ػ‬،ُ‫ٌٍؼظ‬ are mechanically unstable. ٓ١‫ثخ ٌزسغ‬ٍٛ‫ خظبئض ِط‬ٟ٘ ‫اٌظالثخ‬ٚ ،‫خ‬١ٌ‫ِخ اٌزآوً اٌؼب‬ٚ‫ِمب‬ٚ ،‫إٌّخفغ‬ Low coefficient of friction, high wear resistance, and hardness are ‫ العزجذاي‬ٟ‫بع‬١‫ُ اٌم‬١ّ‫ اٌزظ‬ٟ‫ ف‬.‫ اٌشوجخ‬ٚ‫سن أ‬ٌٛ‫ع غشعبد ا‬ّٛ‫ػّش اٌخذِخ ٌّد‬ properties needed to improve the service life of total hip or knee ٚ‫ أ‬ٟٔ‫ٓ اٌشأط اٌّؼذ‬١‫دح ث‬ٛ‫خ‬ٌّٛ‫ رٍه ا‬ٟ٘ ‫ْ ٔمطخ االرظبي‬ٛ‫ رى‬،‫سن‬ٌٛ‫ِفظً ا‬ implants. In the standard design of a hip replacement, the contact point )ٟ‫ئ‬٠‫صْ اٌدض‬ٌٛ‫ ا‬ٌٟ‫ٓ ػب‬١ٍ١‫ث‬٠‫ إ‬ٌٟٛ‫اٌج‬UHMWPE ( ‫ة‬ٛ‫و‬ٚ ٟ‫ى‬١ِ‫شا‬١‫اٌغ‬ is the one between a metal or a ceramic head and an UHMWPE (ultrahigh molecular weight polyethylene) cup Lecture 7 By : ENG.M.A.Hamoda Lecture 5 By : ENG.M.A.Hamoda