המחברים מבקשים להודות Byoung-Lee צ&#39;ול, צ&#39;וי פיליפ ושמואל הו סיוע רב ערך. עבודה זו בוצעה בבית היציקה מולקולרית בבית המעבדה הלאומית לורנס ברקלי, אשר נתמך על ידי משרד של משרד המדע, האנרגיה של יסוד מדעי, של משרד האנרגיה של ארה&quot;ב תחת חוזה מס &#39;DE-AC02-05CH11231 ואת הפחתת האיום הביטחון הסוכנות לא תחת חוזה: IACRO-B0845281.

<ol>
	<li>King, D. S., Fields, C. G., Fields, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+cleavage+method+which+minimizes+side+reactions+following+Fmoc+solid+phase+peptide+synthesis.">A cleavage method which minimizes side reactions following Fmoc solid phase peptide synthesis.</a> Int. J. Pept. Pro. Res. 36, 255-266 (1990).</li><li>Sanii, B., Kudirka, R., Cho, A., Venkateswaran, N., Oliver, G. K., Olson, A. M., Tran, H., Harada, R. M., Tan, L., Zuckermann, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shaken,+not+stirred:+Collapsing+a+peptoid+monolayer+to+produce+free-floating,+stable+nanosheets.">Shaken, not stirred: Collapsing a peptoid monolayer to produce free-floating, stable nanosheets.</a> J. Am. Chem. Soc. , (2011).</li><li>Kudirka, R., Tran, H., Sanii, B., Nam, K. T., Choi, P. H., Venkateswaran, N., Chen, R., Whitelam, S., Zuckermann, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Folding+of+a+single-chain,+information-rich+polypeptoid+sequence+into+a+highly-ordered+nanosheet.">Folding of a single-chain, information-rich polypeptoid sequence into a highly-ordered nanosheet.</a> Bioploymers: Peptide Science. 96, 586-595 (2011).</li><li>Utku, Y., Rohatgi, A., Yoo, B., Zuckermann, R., Pohl, N., Kirshenbaum, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+multistep+synthesis+of+a+bioactive+peptidomimetic+oligomer+for+the+undergraduate+laboratory.">Rapid multistep synthesis of a bioactive peptidomimetic oligomer for the undergraduate laboratory.</a> J. Chem. Ed. 87, 637-639 (2010).</li><li>Fowler, S. A., Blackwell, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure-function+relationships+in+peptoids:+Recent+advances+toward+deciphering+the+structural+requirements+for+biological+function.">Structure-function relationships in peptoids: Recent advances toward deciphering the structural requirements for biological function.</a> Org. Biomol. Chem. 7, 1508-1524 (2009).</li><li>Zuckermann, R. N., Kodadek, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peptoids+as+potential+therapeutics.">Peptoids as potential therapeutics.</a> Curr. Op. Mol. Ther. 11, 299-307 (2009).</li><li>Chongsiriwatana, N. P., Patch, J. A., Czyzewski, A. M., Dohm, M. T., Ivankin, A., Gidalevitz, D., Zuckermann, R. N., Barron, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peptoids+that+mimic+the+structure,+function+and+mechanism+of+helical+antimicrobial+peptides.">Peptoids that mimic the structure, function and mechanism of helical antimicrobial peptides.</a> , 105-2794 (2008).</li><li>Yam, A. Y., Wang, X., Gao, C., Connolly, M. D., Zuckermann, R. N., Bleua, T., Halla, J., Fedynyshyn, J., Allauzen, S., Peretz, D., Salisbury, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Universal+method+for+detection+of+amyloidogenic+misfolded+proteins.">A Universal method for detection of amyloidogenic misfolded proteins.</a> Biochem. 50, 4322-4329 (2011).</li><li>Huang, C. -. Y., Uno, T., Murphy, J. E., Lee, S., Hamer, J. D., Escobedo, J. A., Cohen, F. E., Radhakrishnan, R., Dwarki, V., Zuckermann, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipitoids+-+novel+cationic+lipids+for+cellular+delivery+of+plasmid+DNA+in+vitro.">Lipitoids - novel cationic lipids for cellular delivery of plasmid DNA in vitro.</a> Chem. Biol. 5, 345-354 (1998).</li><li>Schroeder, T., Niemeier, N., Afonin, S., Ulrich, A. S., Krug, H. F., Br&#228;se, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peptoidic+amino-+and+guanidinium-carrier+systems:+Targeted+drug+delivery+into+the+cell+cytosol+or+the+nucleus.">Peptoidic amino- and guanidinium-carrier systems: Targeted drug delivery into the cell cytosol or the nucleus.</a> J. Med. Chem. 51, 376-379 (2008).</li><li>Murnen, H. K., Rosales, A. M., Jaworski, J. N., Segalman, R. A., Zuckermann, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hierarchical+self-assembly+of+a+biomimetic+diblock+copolypeptoid+into+homochiral+super+helices.">Hierarchical self-assembly of a biomimetic diblock copolypeptoid into homochiral super helices.</a> J. Am. Chem. Soc. 132, 16112-16119 (2010).</li><li>Nam, K. T., Shelby, S. A., Marciel, A. B., Choi, P. H., Chen, R., Tan, L., Chu, T. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Free-floating+ultra-thin+two-dimensional+crystals+from+sequence-specific+peptoid+polymers.">Free-floating ultra-thin two-dimensional crystals from sequence-specific peptoid polymers.</a> Nature. Mater. 9, 454-460 (2010).</li><li>Burkoth, T. S., Beausoleil, E., Kaur, S., Tang, D., Cohen, F. E., Zuckermann, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toward+the+synthesis+of+artificial+proteins:+The+Discovery+of+an+amphiphilic+helical+peptoid+assembly.">Toward the synthesis of artificial proteins: The Discovery of an amphiphilic helical peptoid assembly.</a> Chemistry &#38; Biology. 9, 647-654 (2002).</li><li>Murphy, J. E., Uno, T., Hamer, J. D., Cohen, F. E., Dwarki, V., Zuckermann, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Combinatorial+approach+to+the+discovery+of+efficient+cationic+peptoid+reagents+for+gene+delivery.">A Combinatorial approach to the discovery of efficient cationic peptoid reagents for gene delivery.</a> Proc. Natl. Acad. Sci. U. S. A. 95, 1517-1522 (1998).</li><li>Mora, P. u. i. g., Masip, I. s. a. b. e. l., Cort&#233;s, N. u. r. i. a., Marquina, R. e. g. i. n. a., Merino, R. a. m. &. #. 2. 4. 3. ;. n., Merino, J. e. s. &. #. 2. 5. 0. ;. s., Carbonell, T. e. r. e. s. a., Mingarro, I. s. m. a. e. l., Messeguer, A. n. g. e. l., P&#233;rez-Pay&#225;, E. n. r. i. q. u. e. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+from+a+positional+scanning+peptoid+library+of+in+vivo+active+compounds+that+neutralize+bacterial+endotoxins.">Identification from a positional scanning peptoid library of in vivo active compounds that neutralize bacterial endotoxins.</a> J. Med. Chem. 48, 1265-1268 (2005).</li><li>Zuckermann, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Discovery+of+nanomolar+ligands+for+7-transmembrane+G-protein+coupled+receptors+from+a+diverse+(N-substituted)glycine+peptoid+Library.">Discovery of nanomolar ligands for 7-transmembrane G-protein coupled receptors from a diverse (N-substituted)glycine peptoid Library.</a> J. Med. Chem. 37, 2678-2685 (1994).</li><li>Alluri, P., Liu, B., Yu, P., Xiao, X., Kodadek, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+characterization+of+coactivator-binding+peptoids+from+a+combinatorial+library.">Isolation and characterization of coactivator-binding peptoids from a combinatorial library.</a> Moleular Biosystems. 2, 568-579 (2006).</li><li>Figliozzi, G. M., Goldsmith, R., Ng, S., Banville, S. C., Zuckermann, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+N-(substituted)glycine+peptoid+libraries.">Synthesis of N-(substituted)glycine peptoid libraries.</a> Methods Enzymol. 267, 437-447 (1996).</li><li>Culf, A. S., Ouellette, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solid-phase+synthesis+of+N-substituted+glycine+oligomers+(&amp;alpha;+peptoids)+and+derivatives.">Solid-phase synthesis of N-substituted glycine oligomers (&amp;alpha; peptoids) and derivatives.</a> Molecules. 15, 5282-5335 (2010).</li><li>Burkoth, T. S., Fafarman, A. T., Charych, D. H., Connolly, M. D., Zuckermann, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Incorporation+of+unprotected+heterocyclic+side+chains+into+peptoid+oligomers+via+solid-phase+submonomer+synthesis.">Incorporation of unprotected heterocyclic side chains into peptoid oligomers via solid-phase submonomer synthesis.</a> J. Am. Chem. Soc. 125, 8841-8845 (2003).</li></ol>

אין לנו שום דבר לגלות.

יישומים משמעות פרוטוקול זה מתאר שיטה פשוטה ויעילה של סינתזה peptoid ואת מימית הרכבה עצמית של peptoids לתוך nanosheets. רוב המעבדות מסוגלים בקלות לסנתז peptoids כי חומרים זולים, מומחיות בסיסית וטכניקות פשוט מנוצלים 4. כמו כן, הרכבה עצמית של דקים, מאוד מסודרים nanosheets רק דורש חזר בקבוקון הטיה של פתרון peptoid לדלל מימית 2. Peptoids מבטיחים חומרים למחקר ביו הננו כי הם חזקים וגמישים סינטטי עדיין רצף ספציפי מתכונן מאוד 5. Peptoids הוכיחו פעילות ביולוגית (6,7 הרפוי, אבחון 8, משלוח תאיים 90-10) ו מתקפלים לתוך ננו היררכי 3, 11-14. בגלל סינתזה מודולרית שלהם, קומבינטורית peptoid librטלה 15-19 יכול להיות מסונתז בקלות הוקרן עבור סדרה רחבה של פעילויות או נכסים. בפרט, nanosheets לשמש פלטפורמה פוטנציאל דו מימדי פיגומים להציג, mimetics קרום, חיישנים ביולוגיים, mimetics חלבון ייצור המכשיר. עם רצפים שונים בלתי נדלה כמעט אפשרי, את תחום המחקר peptoid היא מתרחבת במהירות. משתני בסינתזה מוצק שלב submonomer של polypeptoids בגלל היכולת לבחור מתוך האלפבית גדול מאוד ומגוון של מונומרים 20, שיטת submonomer צריך שינויים מדי פעם על מקרים בהם הגדלת יעילות צימוד של כל שלב יהיה לשפר את התשואה הכוללת של המוצר. התאגדות של רשתות צד מוגנים heterocyclic מחייב שימוש של חומצה chloroacetic במקום חומצה bromoacetic 21. עקירה פעמים Extended ומעלהריכוזים אמין מועסקים בדרך כלל לאחר כ - 20 הזיווגים עבור peptoid רצפים ארוכים או nucleophilic אמינים פחות. חימום כלי התגובה עד 35 ° C, באמצעות כלי מים במקטורן התגובה, מסייע לנהוג התגובה. עבור נדיף מאוד אמינים כגון isopropylamine, יש להקפיד למנוע אידוי. אמינים בצורה של מלח HCl, כגון HCl t-בוטיל בטא אלנין, צריך להיות חופשי מבוססת לפני שהוצגה בתגובת עקירה. זו יכולה להיות מושגת על ידי המסת או השעיית אמין ב DCM (~ 5g amine/25 מ&quot;ל DCM), ונטרול פתרון equimolar של נתרן הידרוקסידי מימית בתוך משפך separatory. השכבה DCM נאסף את השכבה המימית נשטף עם DCM נוספים. השכבות DCM בשילוב הם מיובשים על פני נתרן גופרתי ולסנן לתוך בקבוק טרום שקל תחתית עגולה. הסר ממס על ידי אידוי רוטרי להניב נפט, ולהקליט את משקל המוצר. דוריןהצעד גרם מחשוף, קוקטייל TFA מחשוף זמן מחשוף תלויה במספר ובמגוון של קבוצות הגנה משמש. הנחיות קוקטיילים מחשוף דומים deprotection מסורתי השסעים פפטיד 1. באופן כללי, 10 דקות incubations נדרשים עבור רצפים ללא הגנה או קבוצות רצפים עם כמה קבוצות מאוד חומצה יציב בהגנה (למשל BOC, trityl). שני incubations שעה מומלץ רצפים עם קבוצות הגנה קשה יותר (למשל, t-בוטיל אסתר, MTR, Pbf) או רצפים עם קבוצות הגנה רבים על מנת להבטיח deprotection מלא של כל שרשרת. המוצרים peptoid גולמי בדרך כלל מתמוססים אצטוניטריל: מים 01:01 (v / v), אבל הפרופורציות אצטוניטריל גבוהה שכיחים עם שרשראות צד עם hydrophobicity הכוללת גבוהה.

<table border="1" style=";text-align:right;direction:rtl"><tbody><tr><td> שם מגיב </td><td> חברה </td><td> מספר קטלוגי </td><td> תגובות </td></tr><tr><td> Dimethylformamide </td><td> EMD </td><td> EM-DX1726P-1 </td><td> 99% + </td></tr><tr><td> N-methylpyrrolidinone </td><td> BDH </td><td> BDH1141-4LP </td><td> 99% </td></tr><tr><td> Bromoacetic חומצה </td><td> Acros אורגניקס </td><td> 200000-106 </td><td> 99% </td></tr><tr><td> 4-Methylpiperidine </td><td> סיגמא אולדריץ&#39; </td><td> M73206 </td><td> 96% </td></tr><tr><td> N, N&#39;-diisopropylcarbodiimide </td><td> Chem-Impex </td><td> 001100 </td><td> 99.5% </td></tr><tr><td> Dichloromethane </td><td> EMD </td><td> EMD-DX0835 </td><td> ACS כיתה </td></tr><tr><td> אצטוניטריל </td><td> EMD </td><td> EM-AX0145P-1 </td><td> 99.8% </td></tr><tr><td> Trifluoroacetic חומצה </td><td> סיגמא אולדריץ&#39; </td><td> T6508 </td><td> 99% </td></tr><tr><td> Triisopropylsilane </td><td> סיגמא אולדריץ&#39; </td><td> 233781 -10G </td><td> עבור מחשוף TFA </td></tr><tr><td> 1,2-Dichloroethane </td><td> JT בייקר </td><td> JTH076-33 </td><td> עבור siliconization כלי זכוכית התגובה </td></tr><tr><td> Phenethylamine </td><td> סיגמא אולדריץ&#39; </td><td> 407,267, 100 מ&quot;ל </td><td> &gt; 99.5% לצד שרשרת הידרופובי אמין </td></tr><tr><td> BOC-ethylenediamine </td><td> CNH טכנולוגיות </td><td> C-1112 </td><td> אמין קטיוני בצד שרשרת </td></tr><tr><td> t-Butyl בטא אלנין HCl </td><td> Chem-Impex הבינלאומי </td><td> 04407 </td><td> אמין anionic בצד שרשרת </td></tr><tr><td> α-Cyano-4-hydroxycinnamic חומצה </td><td> סיגמא אולדריץ&#39; </td><td> C8982-10X10MG </td><td> עבור MALDI מטריקס </td></tr><tr><td> הנילוס האדום </td><td> סיגמא אולדריץ&#39; </td><td> 19123-10 מ&quot;ג </td><td> עבור דימות פלואורסצנטי </td></tr><tr><td> Dichlorodimethylsilane </td><td> סיגמא אולדריץ&#39; </td><td> 80430-F-500 גרם </td><td> עבור siliconization כלי זכוכית התגובה </td></tr><tr><td> פנויה PP fritted עגלהרכס </td><td> אפלייד הפרדות </td><td> 2416 </td><td> 6 מ&quot;ל פוליפרופילן מחסנית עם 20 מ&quot;מ PE frit </td></tr><tr><td> פנויה 3 דרך מתאם luer </td><td> קול בן הזוג </td><td> 31200-80 </td><td> שסתום חד פעמיות עבור סינתזה כלי ידני תגובה </td></tr><tr><td> Luer טבעת נעילה </td><td> קול בן הזוג </td><td> 45503-19 </td><td> ¼ &quot;מתאים הפנויה כלי סינתזה ידני תגובה </td></tr><tr><td> Luer צנרת </td><td> קול בן הזוג </td><td> 45500-20 </td><td> ¼ &quot;מתאים הפנויה כלי סינתזה ידני תגובה </td></tr><tr><td> פנויה PP pipets </td><td> VWR </td><td> 16001-194 </td><td> עבור העברות TFA </td></tr><tr><td> Luer לנעול מזרק פלסטיק </td><td> לאומית מדעי </td><td> S7515-5 </td><td> 6 מזרקים מ&quot;ל </td></tr><tr><td> 1 DRAM בקבוקון זכוכית </td><td> VWR </td><td> 66011-041 </td><td> פנוליות יצוק עם מכסה בורג עם אניה-פוליוויניל בפני עיסת </td></tr><tr><td> 20 מ&quot;ל scintillation בקבוקון </td><td> VWR </td><td> 66022-060 </td><td> עם כובע PP מצורף אניה עיסת נייר </td></tr><tr><td> Secure-Seal דבק spacer </td><td> Invitrogen </td><td> S-24736 </td><td> עבור דימות פלואורסצנטי </td></tr><tr><td> שקופיות הזכוכית </td><td> מיקרוסקופית אלקטרונים למדעים </td><td> 63411 </td><td> עבור דימות פלואורסצנטי </td></tr><tr><td> כיסוי להחליק </td><td> VWR </td><td> 48366-067 </td><td> עבור דימות פלואורסצנטי </td></tr><tr><td> &quot;4 פרוסות הסיליקון </td><td> טד פלה </td><td> 16007 </td><td> טרום קוביות שבבי 5x7 מ&quot;מ </td></tr><tr><td> 0.45 מסנן </td><td> VWR, Acrodisc </td><td> 28143-924 </td><td> עבור HPLC. PTFE ממברנה </td></tr><tr><td> Agarose </td><td> BD </td><td> 212272 </td><td> עבור דימות פלואורסצנטי </td></tr><tr><td> SPE סעפת אבק </td><td> סיגמא אולדריץ&#39; </td><td> 57044 </td><td> דוגמה סעפת ואקום SPE </td></tr><tr><td> כלי זכוכית Fritted </td><td> אייס זכוכית </td><td> 6402-12 </td><td> נקבוביות Cfrit </td></tr><tr><td> פלזמה מנקה / מעקר </td><td> Harrick פלזמה </td><td> PDC-32G </td><td> דוגמה של שואב פלזמה להכין שבבי סיליקון עבור SEM </td></tr></tbody></table>

solid-phase submonomer synthesis of peptoid polymers and their self-assembly into highly-ordered nanosheets

Peptoids הם סוג של רומן biomimetic, הלא טבעי רצף ספציפי heteropolymers כי proteolysis להתנגד, להפגין פעילות ביולוגית חזקה, ומקפלים לתוך ננו מסדר גבוה יותר. מבנית דומה פפטידים, peptoids הם פולי N-להחליף glycines, שבו שרשרות צד מחוברים חנקן ולא פחמן אלפא. הקלות שלהם סינתזה והגיוון מבניים מאפשר בדיקה של עקרונות תכנון בסיסיים לנהוג דה נובו עיצוב, והנדסה של חומרים חדשים ביולוגית הפעילה nanostructured. הנה מדריך פשוט peptoid פרוטוקול סינתזה מוצג המאפשר את הסינתזה של polypeptoids שרשרת ארוכה (עד 50mers) תשואות מצוינות. רק ציוד בסיסי, טכניקות פשוטות (לדוגמא: העברת נוזלים, סינון), וכן חומרים כימיים זמינים מסחרית נדרשים, מה שהופך peptoids תוספת נגיש toolkits חוקרים רבים. עמוד השדרה peptoid הוא גדל אפילו מונומר על v פעםIA השיטה submonomer אשר מורכב בן שני שלבים בנוסף מחזור מונומר: acylation ועקירה. חומצה ראשית, bromoacetic מופעל באתרו עם N, N&#39;-diisopropylcarbodiimide acylates שרף הנכנס אמין משני. עקירה שנית, nucleophilic ברומיד על ידי אמין ראשוני הבא כדי להציג את השרשרת בצד. מחזור בן שני שלבים היא איטרטיבית עד אורך השרשרת הרצוי הוא הגיע. יעילות צימוד של מחזור שני בשלב זה באופן שגרתי עולה 98% ומאפשרת את הסינתזה של peptoids עוד 50 שאריות. רצפים שונים מתכונן מאוד, מדויק מבחינה כימית הם ברי השגה בשיטת submonomer כמו מאות אמינים העיקרי זמינים ניתן לשלב ישירות. Peptoids הם מתעוררים כחומר biomimetic תכליתי למחקר nanobioscience בגלל סינתטי החוסן שלהם גמישות, והזמנת ברמה האטומית. קיפול של אחד בשרשרת, amphiphilic, Information עשיר polypeptoid לתוך nanosheet הפערים הורה הודגם לאחרונה. Peptoid זה 36-mer שמורכבת רק שלושה מונומרים זמינים מסחרית שונים: הידרופובי, קטיוני anionic. השרשראות הידרופובי בצד phenylethyl קבורים הליבה nanosheet ואילו אמין יוניים ורשתות בצד carboxyl ליישר על פניהם הידרופילי. Nanosheets peptoid לשמש פלטפורמה פוטנציאל mimetics קרום, mimetics חלבונים, ייצור המכשיר, וחיישנים. שיטות סינתזה peptoid, היווצרות גיליון הדמיה מיקרוסקופית מתוארים ולספק שיטה פשוטה כדי לאפשר בעתיד nanosheet עיצובים peptoid.

Watch this Scientific Journal Video about Solid-phase Submonomer Synthesis of Peptoid Polymers and their Self-Assembly into Highly-Ordered Nanosheets at JoVE.com

Solid-phase Submonomer Synthesis of Peptoid Polymers and their Self-Assembly into Highly-Ordered Nanosheets

Peptoid פשוטה בכלל ידנית סינתזה שיטה מעורבים ציוד בסיסי ריאגנטים זמינים מסחרית הוא התווה, המאפשר peptoids להיות מסונתז בקלות ברוב המעבדות. סינתזה, טיהור ואפיון של 36mer peptoid amphiphilic מתואר, כמו גם הרכבה עצמית שלה לתוך הפערים הורה nanosheets.

מוצק שלב Submonomer סינתזה של פולימרים Peptoid שלהם ואת הרכבה עצמית לתוך מאוד מסודרים Nanosheets

Peptoids are a novel class of biomimetic, non-natural, sequence-specific heteropolymers that resist proteolysis, exhibit potent biological activity, and ...

solid-phase-submonomer-synthesis-peptoid-polymers-their-self-assembly

Research

JoVE Journal

Bioengineering

29.2K Views.  Lawrence Berkeley National Laboratory. Peptoid פשוטה בכלל ידנית סינתזה שיטה מעורבים ציוד בסיסי ריאגנטים זמינים מסחרית הוא התווה, המאפשר peptoids להיות מסונתז בקלות ברוב המעבדות. סינתזה, טיהור ואפיון של 36mer peptoid amphiphilic מתואר, כמו גם הרכבה עצמית שלה לתוך הפערים הורה nanosheets.

Video: Solid-phase Submonomer Synthesis of Peptoid Polymers and their Self-Assembly into Highly-Ordered Nanosheets

Shape Memory Polymers for Active Cell Culture

Shape memory polymers (SMPs) are a class of "smart" materials that have the ability to change from a fixed, temporary shape to a pre-determined permanent shape upon the application of a stimulus such as heat1-5. In a typical shape memory cycle, the SMP is first deformed at an elevated temperature that is higher than its transition temperature, Ttrans [either the melting temperature (Tm) or the glass transition temperature (Tg)]. The deformation is elastic in nature and mainly leads to a reduction in conformational entropy of the constituent network chains (following the rubber elasticity theory). The deformed SMP is then cooled to a temperature below its Ttrans while maintaining the external strain or stress constant. During cooling, the material transitions to a more rigid state (semi-crystalline or glassy), which kinetically traps or "freezes" the material in this low-entropy state leading to macroscopic shape fixing. Shape recovery is triggered by continuously heating the material through Ttrans under a stress-free (unconstrained) condition. By allowing the network chains (with regained mobility) to relax to their thermodynamically favored, maximal-entropy state, the material changes from the temporary shape to the permanent shape.
Cells are capable of surveying the mechanical properties of their surrounding environment6. The mechanisms through which mechanical interactions between cells and their physical environment control cell behavior are areas of active research. Substrates of defined topography have emerged as powerful tools in the investigation of these mechanisms. Mesoscale, microscale, and nanoscale patterns of substrate topography have been shown to direct cell alignment, cell adhesion, and cell traction forces7-14. These findings have underscored the potential for substrate topography to control and assay the mechanical interactions between cells and their physical environment during cell culture, but the substrates used to date have generally been passive and could not be programmed to change significantly during culture. This physical stasis has limited the potential of topographic substrates to control cells in culture.
Here, active cell culture (ACC) SMP substrates are introduced that employ surface shape memory to provide programmed control of substrate topography and deformation. These substrates demonstrate the ability to transition from a temporary grooved topography to a second, nearly flat memorized topography. This change in topography can be used to control cell behavior under standard cell culture conditions.

A method for developing cell culture substrates with the ability to change topography during culture is described. The method makes use of smart materials known as shape memory polymers that have the ability to memorize a permanent shape. This concept is adaptable to a wide range of materials and applications.

זיכרון צורה פולימרים לתרבות התא הפעיל

Shape memory polymers (SMPs) are a class of "smart" materials that have the ability to change from a fixed, temporary shape to a pre-determined permanent ...

Directed Cellular Self-Assembly to Fabricate Cell-Derived Tissue Rings for Biomechanical Analysis and Tissue Engineering

Each year, hundreds of thousands of patients undergo coronary artery bypass surgery in the United States.1 Approximately one third of these patients do not have suitable autologous donor vessels due to disease progression or previous harvest. The aim of vascular tissue engineering is to develop a suitable alternative source for these bypass grafts. In addition, engineered vascular tissue may prove valuable as living vascular models to study cardiovascular diseases. Several promising approaches to engineering blood vessels have been explored, with many recent studies focusing on development and analysis of cell-based methods.2-5 Herein, we present a method to rapidly self-assemble cells into 3D tissue rings that can be used in vitro to model vascular tissues.
To do this, suspensions of smooth muscle cells are seeded into round-bottomed annular agarose wells. The non-adhesive properties of the agarose allow the cells to settle, aggregate and contract around a post at the center of the well to form a cohesive tissue ring.6,7 These rings can be cultured for several days prior to harvesting for mechanical, physiological, biochemical, or histological analysis. We have shown that these cell-derived tissue rings yield at 100-500 kPa ultimate tensile strength8 which exceeds the value reported for other tissue engineered vascular constructs cultured for similar durations (&lt;30 kPa).9,10 Our results demonstrate that robust cell-derived vascular tissue ring generation can be achieved within a short time period, and offers the opportunity for direct and quantitative assessment of the contributions of cells and cell-derived matrix (CDM) to vascular tissue structure and function.

This article outlines a versatile method to create cell-derived tissue rings by cellular self-assembly. Smooth muscle cells seeded into ring-shaped agarose wells aggregate and contract to form robust three-dimensional (3D) tissues within 7 days. Millimeter-scale tissue rings are conducive to mechanical testing and serve as building blocks for tissue assembly.

בימוי נייד הרכבה עצמית לפברק Cell-נגזר טבעות רקמות לניתוח biomechanical הנדסת רקמות

Each year, hundreds of thousands of patients undergo coronary artery bypass surgery in the United States.1 Approximately one third of these patients do ...

Optical Control of Living Cells Electrical Activity by Conjugated Polymers

Hybrid interfaces between organic semiconductors and living tissues represent a new tool for in-vitro and in-vivo applications. In particular, conjugated polymers display several optimal properties as substrates for biological systems, such as good biocompatibility, excellent mechanical properties, cheap and easy processing technology, and possibility of deposition on light, thin and flexible substrates. These materials have been employed for cellular interfaces like neural probes, transistors for excitation and recording of neural activity, biosensors and actuators for drug release. Recent experiments have also demonstrated the possibility to use conjugated polymers for all-optical modulation of the electrical activity of cells. Several in-vitro study cases have been reported, including primary neuronal networks, astrocytes and secondary line cells. Moreover, signal photo-transduction mediated by organic polymers has been shown to restore light sensitivity in degenerated retinas, suggesting that these devices may be used for artificial retinal prosthesis in the future. All in all, light sensitive conjugated polymers represent a new approach for optical modulation of cellular activity.
In this work, all the steps required to fabricate a bio-polymer interface for optical excitation of living cells are described. The function of the active interface is to transduce the light stimulus into a modulation of the cell membrane potential. As a study case, useful for in-vitro studies, a polythiophene thin film is used as the functional, light absorbing layer, and Human Embryonic Kidney (HEK-293) cells are employed as the biological component of the interface. Practical examples of successful control of the cell membrane potential upon stimulation with light pulses of different duration are provided. In particular, it is shown that both depolarizing and hyperpolarizing effects on the cell membrane can be achieved depending on the duration of the light stimulus. The reported protocol is of general validity and can be straightforwardly extended to other biological preparations.

A method for stimulation of in-vitro cell cultures electrical activity with visible light, based on the use of organic semiconducting polymers is described.

שליטה אופטית של תאי חיים פעילות חשמלית על ידי פולימרים מצומדות

Hybrid interfaces between organic semiconductors and living tissues represent a new tool for in-vitro and in-vivo applications. In particular, conjugated ...

Fabrication of a Dipole-assisted Solid Phase Extraction Microchip for Trace Metal Analysis in Water Samples

This paper describes a fabrication protocol for a dipole-assisted solid phase extraction (SPE) microchip available for trace metal analysis in water samples. A brief overview of the evolution of chip-based SPE techniques is provided. This is followed by an introduction to specific polymeric materials and their role in SPE. To develop an innovative dipole-assisted SPE technique, a chlorine (Cl)-containing SPE functionality was implanted into a poly(methyl methacrylate) (PMMA) microchip. Herein, diverse analytical techniques including contact angle analysis, Raman spectroscopic analysis, and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis were employed to validate the utility of the implantation protocol of the C-Cl moieties on the PMMA. The analytical results of the X-ray absorption near-edge structure (XANES) analysis also demonstrated the feasibility of the Cl-containing PMMA used as an extraction medium by virtue of the dipole-ion interactions between the highly electronegative C-Cl moieties and the positively charged metal ions.

The fabrication protocol of a dipole-assisted solid phase extraction microchip for the trace metal analysis is presented.

המצאה של Microchip הפקת דיפול בסיוע שלב מוצק עבור ניתוח מתכת עקבות בדגימות מים

This paper describes a fabrication protocol for a dipole-assisted solid phase extraction (SPE) microchip available for trace metal analysis in water ...

Synthesis of Gold Nanoparticle Integrated Photo-responsive Liposomes and Measurement of Their Microbubble Cavitation upon Pulse Laser Excitation

Photo-responsive nanoparticles (NPs) have received considerable attention because of their potential in providing spatial, temporal, and dosage control over the drug release. However, most of the relevant technologies are still in the development process and are unprocurable by clinics. Here, we describe a facile fabrication of these photo-responsive NPs with commercially available gold NPs and thermo-responsive liposomes. Calcein is used as a model drug to evaluate the encapsulation efficiency and the release kinetic profile upon heat/light stimulation. Finally, we show that this photo-triggered release is due to the membrane disruption caused by microbubble cavitation, which can be measured with hydrophone.

This protocol describes a simple preparation method for gold nanoparticle integrated photo-responsive liposomes with the commercially available materials. It also shows how to measure the microbubble cavitation process of the synthesized liposomes upon the treatment of pulsed laser.

סינתזה של משולב זהב Nanoparticle תמונה המגיבים ליפוזומים ומדידה של microbubble Cavitation שלהם על עירור לייזר דופק

Photo-responsive nanoparticles (NPs) have received considerable attention because of their potential in providing spatial, temporal, and dosage control ...

High-throughput Identification of Bacteria Repellent Polymers for Medical Devices

Medical devices are often associated with hospital-acquired infections, which place enormous strain on patients and the healthcare system as well as contributing to antimicrobial resistance. One possible avenue for the reduction of device-associated infections is the identification of bacteria-repellent polymer coatings for these devices, which would prevent bacterial binding at the initial attachment step. A method for the identification of such repellent polymers, based on the parallel screening of hundreds of polymers using a microarray, is described here. This high-throughput method resulted in the identification of a range of promising polymers that resisted binding of various clinically relevant bacterial species individually and also as multi-species communities. One polymer, PA13 (poly(methylmethacrylate-co-dimethylacrylamide)), demonstrated significant reduction in attachment of a number of hospital isolates when coated onto two commercially available central venous catheters. The method described could be applied to identify polymers for a wide range of applications in which modification of bacterial attachment is important.

A high-throughput microarray method for the identification of polymers which reduce bacterial surface binding on medical devices is described.

זיהוי תפוקה גבוהה של חיידקים פולימרים דוחה עבור אביזרים ומכשור רפואי

Medical devices are often associated with hospital-acquired infections, which place enormous strain on patients and the healthcare system as well as ...

Fabricating Degradable Thermoresponsive Hydrogels on Multiple Length Scales via Reactive Extrusion, Microfluidics, Self-assembly, and Electrospinning

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), their ultimate clinical use has been hampered by the lack of biologically-relevant degradation observed for most smart materials. This is particularly true for temperature-responsive hydrogels, which are almost uniformly based on polymers that are functionally non-degradable (e.g., poly(N-isopropylacrylamide) (PNIPAM) or poly(oligoethylene glycol methacrylate) (POEGMA)). As such, to effectively translate the potential of thermoresponsive hydrogels to the challenges of remote-controlled or metabolism-regulated drug delivery, cell scaffolds with tunable cell-material interactions, theranostic materials with the potential for both imaging and drug delivery, and other such applications, a method is required to render the hydrogels (if not fully degradable) at least capable of renal clearance following the required lifetime of the material. To that end, this protocol describes the preparation of hydrolytically-degradable hydrazone-crosslinked hydrogels on multiple length scales based on the reaction between hydrazide and aldehyde-functionalized PNIPAM or POEGMA oligomers with molecular weights below the renal filtration limit. Specifically, methods to fabricate degradable thermoresponsive bulk hydrogels (using a double barrel syringe technique), hydrogel particles (on both the microscale through the use of a microfluidics platform facilitating simultaneous mixing and emulsification of the precursor polymers and the nanoscale through the use of a thermally-driven self-assembly and cross-linking method), and hydrogel nanofibers (using a reactive electrospinning strategy) are described. In each case, hydrogels with temperature-responsive properties similar to those achieved via conventional free radical cross-linking processes can be achieved, but the hydrazone cross-linked network can be degraded over time to re-form the oligomeric precursor polymers and enable clearance. As such, we anticipate these methods (which may be generically applied to any synthetic water-soluble polymer, not just smart materials) will enable easier translation of synthetic smart materials to clinical applications.

Protocols are described for the fabrication of degradable thermoresponsive hydrogels based on hydrazone cross-linking of polymeric oligomers on the bulk scale, microscale, and nanoscale, the latter for preparation of both gel nanoparticles and nanofibers.

בדיית Thermoresponsive Hydrogels מתכלה-פיסיקליות מרובים באמצעות שחול תגובתי, מיקרופלואידיקה, הרכבה עצמית, Electrospinning

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), ...

Aqueous Droplets Used as Enzymatic Microreactors and Their Electromagnetic Actuation

For the successful implementation of microfluidic reaction systems, such as PCR and electrophoresis, the movement of small liquid volumes is essential. In conventional lab-on-a-chip-platforms, solvents and samples are passed through defined microfluidic channels with complex flow control installations. The droplet actuation platform presented here is a promising alternative. With it, it is possible to move a liquid drop (microreactor) on a planar surface of a reaction platform (lab-in-a-drop). The actuation of microreactors on the hydrophobic surface of the platform is based on the use of magnetic forces acting on the outer shell of the liquid drops which is made of a thin layer of superhydrophobic magnetite particles. The hydrophobic surface of the platform is needed to avoid any contact between the liquid core and the surface to allow a smooth movement of the microreactor. On the platform, one or more microreactors with volumes of 10 &#181;L can be positioned and moved simultaneously. The platform itself consists of a 3 x 3 matrix of electrical double coils which accommodate either neodymium or iron cores. The magnetic field gradients are automatically controlled. By variation of the magnetic field gradients, the microreactors' magnetic hydrophobic shell can be manipulated automatically to move the microreactor or open the shell reversibly. Reactions of substrates and corresponding enzymes can be initiated by merging the microreactors or bringing them into contact with surface immobilized catalysts.

Lab-in-a-drop reaction systems allow the versatile implementation of complex reactions in a microfluidic scale. An automated actuation platform consisting of a 3 x 3 matrix of electromagnetic coils was developed and successfully used to merge two 10 &#181;L microreactors and thereby initiate an enzymatic reaction in the resulting liquid marbles.

טיפות מימית משמש Microreactors אנזימטיות, הופעה אלקטרומגנטית שלהם

For the successful implementation of microfluidic reaction systems, such as PCR and electrophoresis, the movement of small liquid volumes is essential. In ...

Synthesis of Cationized Magnetoferritin for Ultra-fast Magnetization of Cells

Many important biomedical applications, such as cell imaging and remote manipulation, can be achieved by labeling cells with superparamagnetic iron oxide nanoparticles (SPIONs). Achieving sufficient cellular uptake of SPIONs is a challenge that has traditionally been met by exposing cells to elevated concentrations of SPIONs or by prolonging exposure times (up to 72 hr). However, these strategies are likely to mediate toxicity. Here, we present the synthesis of the protein-based SPION magnetoferritin as well as a facile surface functionalization protocol that enables rapid cell magnetization using low exposure concentrations. The SPION core of magnetoferritin consists of cobalt-doped iron oxide with an average particle diameter of 8.2 nm mineralized inside the cavity of horse spleen apo-ferritin. Chemical cationization of magnetoferritin produced a novel, highly membrane-active SPION that magnetized human mesenchymal stem cells (hMSCs) using incubation times as short as one minute and iron concentrations as lows as 0.2 mM.

A protocol for the synthesis and cationization of cobalt-doped magnetoferritin is presented, as well as a method to rapidly magnetize stem cells with cationized magnetoferritin.

סינתזה של Cationized Magnetoferritin עבור המגנטיזציה אולטרה-מהירה של תאים

Many important biomedical applications, such as cell imaging and remote manipulation, can be achieved by labeling cells with superparamagnetic iron oxide ...

Engineering Molecular Recognition with Bio-mimetic Polymers on Single Walled Carbon Nanotubes

Semiconducting single-wall carbon nanotubes (SWNTs) are a class of optically active nanomaterial that fluoresce in the near infrared, coinciding with the optical window where biological samples are most transparent. Here, we outline techniques to adsorb amphiphilic polymers and polynucleic acids onto the surface of SWNTs to engineer their corona phases and create novel molecular sensors for small molecules and proteins. These functionalized SWNT sensors are both biocompatible and stable. Polymers are adsorbed onto the nanotube surface either by direct sonication of SWNTs and polymer or by suspending SWNTs using a surfactant followed by dialysis with polymer. The fluorescence emission, stability, and response of these sensors to target analytes are confirmed using absorbance and near-infrared fluorescence spectroscopy. Furthermore, we demonstrate surface immobilization of the sensors onto glass slides to enable single-molecule fluorescence microscopy to characterize polymer adsorption and analyte binding kinetics.

We present a protocol for engineering the corona phase of near infrared fluorescent single walled carbon nanotubes (SWNTs) using amphiphilic polymers and DNA to develop sensors for molecular targets without known recognition elements.

הכרה מולקולרית הנדסה עם פולימרים ביו-מימטיים על פחמן Walled יחיד

Semiconducting single-wall carbon nanotubes (SWNTs) are a class of optically active nanomaterial that fluoresce in the near infrared, coinciding with the ...