Pallav Kolli, פאביו Settecase, Amans מתיו, ורוברט טיילור מקליפורניה בסן פרנסיסקו, טים רוברטס מאוניברסיטת פנסילבניה מקורות מימון NIH לב ריאת דם המכון הלאומי (NHLBI) פרס (מ &#39;וילסון): 1R01HL076486 אגודת Neuroradiology המחקר ופרס מלגת קרן חינוך האמריקאי (ס Hetts) NIH המכון הלאומי לדימות וBioengineering יו (NIBIB) פרס (ס Hetts): 1R01EB012031

1. Microcoil ייצור <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> השג microcatheter זמין מסחרי (צנתר למשל 2.3F Rapid Transit Cordis Neurovascular, Raynham, MA) למצע. </li><li style=";text-align:right;direction:rtl"> ודא צנתרים אין רכיבי ברזליות, נחשבים MR-בטוח, שונה בגודל 2.3-3.0 פ </li><li style=";text-align:right;direction:rtl"> גמגום בשכבת הדבקת טיטניום אחרי שכבת זרע נחושת אל 1-2 מ&quot;מ צינור בידוד יתר. חומרים אפשריים כוללים polyimide או אלומינה (מתקדמת קרמיקת Ortech, סקרמנטו, קליפורניה). </li><li style=";text-align:right;direction:rtl"> Electrodeposit שכבת photoresist חיובית באמצעות יפלי של PEPR-2400 (כיום נמכרים על ידי דאו כימיקלים תחת שם Intervia 3D-P). תוצאות Electrodeposition בציפוי אחיד על פני השטח הגליליים אינם מישוריים. </li><li style=";text-align:right;direction:rtl"> Photoresist חשוף על ידי מערכת ייחודית ליזר ישיר לכתוב (ליזר מחרטה, מערכת לא מסחרית שפותחה במעבדה הלאומית לורנס ליברמור) בדפוס צורת הסליל הרצוי (איור 2 א). זה modification של הטכניקה שתואר במקור ב- MALBA אח&#39; 14. </li><li style=";text-align:right;direction:rtl"> לפתח photoresist נחשף בפתרון 1% אשלגן פחם ב 35 ° C. </li><li style=";text-align:right;direction:rtl"> נחושת electroplated דרך המסכה שנותרה להתנגד ליצירת סליל הרצוי. המערכת יכולה לפברק הן סולנואיד ו( מסלול מירוצים) דפוסי נחושת הלמהולץ (איורים ו2C 2D). </li><li style=";text-align:right;direction:rtl"> לאחר electrodeposition נחושת, להסיר את ההתנגדות עם מפתח חם. הסר את שכבת זרע הנחושת, ואחריו שכבת הדבקת טיטניום. </li><li style=";text-align:right;direction:rtl"> צרף צינור הבידוד לקצה הצנתר באמצעות עטיפה כדי להשלים את ההרכבה. ודא שהעטיפה מכסה את הקצה המלופף כולו. כדי להרכיב צנתרים רבי ציר למקם מבני צינור בידוד בתוך אחד את השני כפי שמוצג באיור 2E. </li><li style=";text-align:right;direction:rtl"> חוטי נחושת אשכול באמצעות לומן של microcatheter וההלחמה לסלילים בקצה. </li><li style=";text-align:right;direction:rtl"> לשנות ולקצר 6 מטר RJ11 כבל טלפון t3 רגל o באורך. </li><li style=";text-align:right;direction:rtl"> חבור את חוטי נחושת הנובעים מרכזת הקצה האחורית של microcatheter לקו השונה 3 הרגל לשקע טלפון השידור. </li></ol> 2. התקנת Waterbath <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> עושה חור קטן במרכזו של הצד של קערת פלסטיק על 5 סנטימטר מתחתית. </li><li style=";text-align:right;direction:rtl"> הכנס נדן 9F אוואנטי Cordis כלי דם (Cordis Endovascular, מיאמי אגמים, פלורידה) דרך החור. </li><li style=";text-align:right;direction:rtl"> חותך את הקצה הדיסטלי של נדן כלי הדם עוזב 4 סנטימטר פיסה ארוכה המשתרעת באגן. </li><li style=";text-align:right;direction:rtl"> בסופו של הנדן, לצרף סתום דמום או Thuoy-Borst מסתובב לייצב את המיקום של microcatheter. </li><li style=";text-align:right;direction:rtl"> מלא את הכיור במים מזוקקים הבטחה מלא שקיעתו של המנגנון. </li><li style=";text-align:right;direction:rtl"> הכנס את הקטטר עם טיפ מפותל דרך המעטה וסתום כלי הדם. </li><li style=";text-align:right;direction:rtl"> למדוד ולתעד את האורך בלתי המרוסן של microcatheter משתרע מהשסתום בwaterbath. </li><li style=";text-align:right;direction:rtl"> הנח waterbath עם מייקרומערכת צנתר בתוך המגנט של MR הסורק ולהתמצא ביחס לשעמם של המגנט. </li><li style=";text-align:right;direction:rtl"> חבר את כבל הטלפון השונה 3 רגל המחובר לקטטר לקו 25 רגל RJ11 טלפון באמצעות כבל הילוכים 2-way לשקע טלפון. </li><li style=";text-align:right;direction:rtl"> חבר את הקצה השני של כבל טלפון הרגל 25 עד אספקה ​​למבדה LPD-422-FM כפולה מוסדרת יכולת לספק עד 1 של נוכחי למכשיר. </li><li style=";text-align:right;direction:rtl"> מניח את קווי ההולכה דרך מוליך גל ומקור הכח מחוץ לחדר סורק MR מחוץ לשורת 5 גאוס. </li></ol> 3. התקנת פנטום כלי <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> לבנות פנטום כלי חלול עם צומת בצורת אות V מצינור גומי לפני הניסויים. </li><li style=";text-align:right;direction:rtl"> מלא פנטום הכלי עם פתרון של 0.0102 M gadopentetate dimeglumine (GdDTPA) (Magnevist, באייר בריאות תרופות, Montville, ניו ג&#39;רזי) במים מזוקקים כדי ליצור ניגוד בין הכלים ואת רקע הפנטום. </li><li style=";text-align:right;direction:rtl"> להרכיב microcמערכת atheter כפי שמתוארת בצעדים 1.1 דרך 1.9. חבר קטטר לאספקת החשמל והעמדה כמתואר בשלבים 2.9-2.11. </li><li style=";text-align:right;direction:rtl"> מקם את קצה microcatheter בבסיס פתיחת כלי הדם. </li><li style=";text-align:right;direction:rtl"> הנח את הפנטום בתוך המגנט של MR הסורק ולהתמצא ביחס לשעמם של המגנט. </li></ol> 4. הדמיית תהודה מגנטית <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> ביצוע הדמיה עם קלינית MR מערכת 1.5T (סימנס Avanto, SW: syngo B13, Erlangen, גרמניה; פיליפס Achieva, SW 2.1 שחרור, קליבלנד, אוהיו). </li><li style=";text-align:right;direction:rtl"> החל &lt;50 mA נוכחי כדי להמחיש את עמדת קצה הצנתר. תחת MRI, מומנט מגנטי קטן יהיה מיוצר בקצה הצנתר לדמיין חפץ מובחן של צורות שונות בהתאם לסלילים הם אנרגיה. </li><li style=";text-align:right;direction:rtl"> החל כמויות משתנות של נוכחי בטווח של ± 100 mA ממקור הכח הכפול מבדה לסלילים ולבחון סטיית קצה (איורי 3A-3C) במים baה התקנה. בגלל סטיית קצה היא כמעט מיידית, נוכחי צריכים להיות מיושם רק שניות ל~ 1-2 לדמיין סטייה מרבית. </li><li style=";text-align:right;direction:rtl"> חזור ולהקליט יישומים רצופים של כמויות שנקבעו של נוכחי. </li><li style=";text-align:right;direction:rtl"> חזור על השלב 4.2 ובמקביל דוחף את הקטטר ביד ומאפשרת קידום מכאני באמצעות כלי הפנטום (איורים 4 א ו -4 ב). החל נוכחי בנקודת הסניף כדי להסיט את קצה הצנתר לתוך הכלי הרצוי. קידום הצנתר לתוך כלי קיבול הסניף על ידי דחיפת קצה הצנתר (האיור 4C) באופן ידני. לחזור בו קטטר להסתעפות כלי הדם והחוזר בסניף ההפוך (האיור 4D). </li><li style=";text-align:right;direction:rtl"> לרכוש תמונות MR באמצעות רצף תמונה-2D פלאש (TR = 30 אלפיות שניות, TE = 1.4 אלפיות שניים, מטריצה ​​של 256 X128 וזווית להעיף ~ 30 מעלות). </li></ol> 5. מדידות הסטה לנתח ולמדוד deflections זווית של תמונות שנתפסו במהלךניסויי אמבט מים עם יישומי מחשב שונים (כל הדמיה דיגיטלית ותקשורת ברפואה (DICOM) Viewer).

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ד&quot;ר Hetts קבל להעניק תמיכה מחברת סטרייקר והוא יועץ בשכר לדרך משי רפואי, Inc

כאן אנו מתארים את הפרוטוקול לסטייה של microcatheter בסורק MRI. הפרמטרים המרכזיים להצלחה הם יישום מדויק של זרם ומדידה של זווית הטיה. מדידה מדויקת של זווית סטייה היא השגיאה הסבירה ביותר נתקלה בפרוטוקול זה. הזוויות שנתפסו בתמונות MR במהלך ניסוי waterbath עשויות להיות שונות מערכים בפ...

נהלי endovascular בוצעו בהדרכת שימוש רפואה התערבותית רנטגן ככלי לניווט צנתר דרך כלי דם לטיפול בכמה מחלות עיקריות, כגון מפרצה במוח, שבץ איסכמי, גידולים מוצקים, טרשת עורקים והפרעות קצב לב מיקוד יותר ממיליון חולים בשנה 1 בעולם - 5. עם השימוש בחומר ניגוד, ניווט באמצעות מערכת כלי דם מושגת באמצעות סיבוב ידני של קטטר והמכאני הקידום בעבודת היד של מתערב 6. עם זאת, ניווט דרך כלי דם מפותלים קטנים סביב עיקולי כלי דם רבים הופך קשה יותר ויותר, האריך את הזמן לפני שהגיע לאתר היעד. זה מהווה בעיה להליכים תלויים זמן כגון הסרת קריש בכלי דם occluded. בנוסף, הליכים ממושכים להגדיל את מינון הקרינה וליצור פוטנציאל לתופעות לוואי 7-11. עם זאת, נהלי endovascular מתבצעים תחת Magnetiג תהודה עשויה לספק פתרון. השדה המגנטי החזק הומוגנית של סורק MRI יכול להיות מנוצל לניווט קצה צנתר על ידי שלט רחוק 12,13. הנוכחי יחול על microcoil ממוקם בקצה צנתר גורם למומנט מגנטי קטן, שחווה מומנט כפי שהוא מתיישר עם הקדח של סורק ה-MRI 13 (איור 1). אם זרם חשמלי מופעל בסליל יחיד, קצה הצנתר ניתן מוסח במישור אחד על ידי שלט רחוק. אם שלושה סלילים בקצה צנתר הם אנרגיה, סטיית קצה צנתר ניתן להשיג בשלושה ממדים. לפיכך, היגוי הקל המגנטי של צנתר יש פוטנציאל להגדיל את המהירות ויעילות של כלי דם ניווט בהליכי endovascular, אשר יכול להפחית פעמי הליך ולשפר את תוצאות מטופל. במחקר זה, בדק אם נוכחי יחול על קטטר endovascular microcoil שקצו יכול לייצר אמין והמבוקר deflectiתוספות תחת MR-הדרכה כבדיקה ראשונית של מחקרי ניווט קטטר.

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 <td>Bayer HealthCare Pharmaceuticals Inc. </td>
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 <td>Carolina</td>
 <td>879190</td>
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magnetically-assisted remote controlled microcatheter tip deflection under magnetic resonance imaging

נהלי רנטגן fluoroscopy המודרך endovascular יש כמה מגבלות משמעותיות, כולל ניווט קשה קטטר ושימוש בקרינה מייננת, אשר באופן פוטנציאלי ניתן להתגבר באמצעות קטטר מגנטי ניתן להיגוי תחת הדרכת MR. המטרה העיקרית של עבודה זו היא לפתח microcatheter הטיפ שניתן לשליטה מרחוק באמצעות השדה המגנטי של סורק MRI. פרוטוקול זה נועד לתאר את הנהלים להגשת בקשה הנוכחית לmicrocatheter microcoil שקצו כדי לייצר deflections העקבי ושליטה. Microcoil היה מפוברק באמצעות ליתוגרפיה מחרטת הליזר על גבי קטטר endovascular polyimide שקצו. בבדיקת המבחנה בוצעה בwaterbath ופנטום כלי תחת הדרכתו של מערכת 1.5-T MR שימוש חופשי נקיפת מצב יציב (SSFP) רצף. כמויות שונות של נוכחי יושמו את סלילי microcatheter לייצר meadeflections sureable הקצה ולנווט ברוחות רפאים של כלי דם. הפיתוח של המכשיר הזה מספק פלטפורמה לבדיקה והזדמנות לחולל מהפכה בסביבת ה-MRI התערבותית endovascular עתיד.

מהפרוטוקול שתואר לעיל, זווית סטייה בין 0 ל 90 מעלות צריכה להיות שנצפתה מיישום של 50-300 mA זרם מועבר בו זמנית לשני הסלילים של מערכת microcatheter סליל הלמהולץ (2E איור) סולנואיד ומשולב. עלייה נוכחית מיושם צריכה לגרום לעלייה בזווית הטית microcatheter, תוך היפוך בקוטביות נוכחית צ?...

Watch this Scientific Journal Video about Magnetically-Assisted Remote Controlled Microcatheter Tip Deflection under Magnetic Resonance Imaging at JoVE.com

Magnetically-Assisted Remote Controlled Microcatheter Tip Deflection under Magnetic Resonance Imaging

נוכחי יחול על microcatheter endovascular עם טיפ microcoil נעשה על ידי יתוגרפיה מחרטת הליזר יכול להשיג שליטת deflections תחת תהודה מגנטית הדרכה (MR), אשר עשוי לשפר את המהירות ויעילות של ניווט של מערכת כלי דם במהלך הליכי endovascular שונים.

הסטת Assisted-מגנטי מרחוק מבוקרת Microcatheter עצה תחת הדמיית תהודה מגנטית

X-ray fluoroscopy-guided  endovascular procedures have several significant limitations, including  difficult catheter navigation and use of ionizing ...

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12.3K Views.  University of California, San Francisco. נוכחי יחול על microcatheter endovascular עם טיפ microcoil נעשה על ידי יתוגרפיה מחרטת הליזר יכול להשיג שליטת deflections תחת תהודה מגנטית הדרכה (MR), אשר עשוי לשפר את המהירות ויעילות של ניווט של מערכת כלי דם במהלך הליכי endovascular שונים.

Video: Magnetically-Assisted Remote Controlled Microcatheter Tip Deflection under Magnetic Resonance Imaging

Magnetic Resonance Elastography Methodology for the Evaluation of Tissue Engineered Construct Growth

Traditional mechanical testing often results in the destruction of the sample, and in the case of long term tissue engineered construct studies, the use of destructive assessment is not acceptable. A proposed alternative is the use of an imaging process called magnetic resonance elastography. Elastography is a nondestructive method for determining the engineered outcome by measuring local mechanical property values (i.e., complex shear modulus), which are essential markers for identifying the structure and functionality of a tissue. As a noninvasive means for evaluation, the monitoring of engineered constructs with imaging modalities such as magnetic resonance imaging (MRI) has seen increasing interest in the past decade1. For example, the magnetic resonance (MR) techniques of diffusion and relaxometry have been able to characterize the changes in chemical and physical properties during engineered tissue development2. The method proposed in the following protocol uses microscopic magnetic resonance elastography (&mu;MRE) as a noninvasive MR based technique for measuring the mechanical properties of small soft tissues3. MRE is achieved by coupling a sonic mechanical actuator with the tissue of interest and recording the shear wave propagation with an MR scanner4. Recently, &mu;MRE has been applied in tissue engineering to acquire essential growth information that is traditionally measured using destructive mechanical macroscopic techniques5. In the following procedure, elastography is achieved through the imaging of engineered constructs with a modified Hahn spin-echo sequence coupled with a mechanical actuator. As shown in Figure 1, the modified sequence synchronizes image acquisition with the transmission of external shear waves; subsequently, the motion is sensitized through the use of oscillating bipolar pairs. Following collection of images with positive and negative motion sensitization, complex division of the data produce a shear wave image. Then, the image is assessed using an inversion algorithm to generate a shear stiffness map6. The resulting measurements at each voxel have been shown to strongly correlate (R2&gt;0.9914) with data collected using dynamic mechanical analysis7. In this study, elastography is integrated into the tissue development process for monitoring human mesenchymal stem cell (hMSC) differentiation into adipogenic and osteogenic constructs as shown in Figure 2.

The procedure demonstrates the methodology of magnetic resonance elastography for monitoring the engineered outcome of adipose and osteogenic tissue engineered constructs through noninvasive local assessment of the mechanical properties using microscopic magnetic resonance elastography (&mu;MRE).

תהודה מגנטית elastography מתודולוגיה להערכת של רקמות מהונדסות צמיחה Construct

Traditional mechanical testing often results in the destruction of the sample, and in the case of long term tissue engineered construct studies, the use ...

Remote Magnetic Actuation of Micrometric Probes for in situ 3D Mapping of Bacterial Biofilm Physical Properties

Bacterial adhesion and growth on interfaces lead to the formation of three-dimensional heterogeneous structures so-called biofilms. The cells dwelling in these structures are held together by physical interactions mediated by a network of extracellular polymeric substances. Bacterial biofilms impact many human activities and the understanding of their properties is crucial for a better control of their development &#8212; maintenance or eradication &#8212; depending on their adverse or beneficial outcome. This paper describes a novel methodology aiming to measure in situ the local physical properties of the biofilm that had been, until now, examined only from a macroscopic and homogeneous material perspective. The experiment described here&#160;involves introducing magnetic particles into a growing biofilm to seed local probes that can be remotely actuated without disturbing the structural properties of the biofilm. Dedicated magnetic tweezers were developed to exert a defined force on each particle embedded in the biofilm. The setup is mounted on the stage of a microscope to enable the&#160;recording of time-lapse images of the particle-pulling period. The particle trajectories are then extracted from the pulling sequence and the local viscoelastic parameters are derived from each particle displacement curve, thereby providing the 3D-spatial distribution of the parameters. Gaining insights into the biofilm mechanical profile is essential from an engineer&#39;s point of view for biofilm control purposes but also from a fundamental perspective to clarify the relationship between the architectural properties and the specific biology of these structures.

Remote Magnetic Actuation of Micrometric Probes for in situ 3D Mapping of Bacterial Biofilm Physical Properties

This paper shows an original methodology based on the remote actuation of magnetic particles seeded in a bacterial biofilm and the development of dedicated magnetic tweezers to measure in situ the local mechanical properties of the complex living material built by micro-organisms at interfaces.

הפעלה של שלט מגנטי של בדיקות מיקרומטר<em&gt; באתר</em&gt; 3D מיפוי של תכונות פיסיקליות biofilm חיידקים

Bacterial adhesion and growth on interfaces lead to the formation of three-dimensional heterogeneous structures so-called biofilms. The cells dwelling in ...

Custom-designed Laser-based Heating Apparatus for Triggered Release of Cisplatin from Thermosensitive Liposomes with Magnetic Resonance Image Guidance

Liposomes have been employed as drug delivery systems to target solid tumors through exploitation of the enhanced permeability and retention (EPR) effect resulting in significant reductions in systemic toxicity. Nonetheless, insufficient release of encapsulated drug from liposomes has limited their clinical efficacy. Temperature-sensitive liposomes have been engineered to provide site-specific release of drug in order to overcome the problem of limited tumor drug bioavailability. Our lab has designed and developed a heat-activated thermosensitive liposome formulation of cisplatin (CDDP), known as HTLC, to provide triggered release of CDDP at solid tumors. Heat-activated delivery in vivo was achieved in murine models using a custom-built laser-based heating apparatus that provides a conformal heating pattern at the tumor site as confirmed by MR thermometry (MRT). A fiber optic temperature monitoring device was used to measure the temperature in real-time during the entire heating period with online adjustment of heat delivery by alternating the laser power. Drug delivery was optimized under magnetic resonance (MR) image guidance by co-encapsulation of an MR contrast agent (i.e.,&#160;gadoteridol) along with CDDP into the thermosensitive liposomes as a means to validate the heating protocol and to assess tumor accumulation. The heating protocol consisted of a preheating period of 5 min prior to administration of HTLC and 20 min heating post-injection. This heating protocol resulted in effective release of the encapsulated agents with the highest MR signal change observed in the heated tumor in comparison to the unheated tumor and muscle. This study demonstrated the successful application of the laser-based heating apparatus for preclinical thermosensitive liposome development and the importance of MR-guided validation of the heating protocol for optimization of drug delivery.

AN MRI-compatible&#160;custom-designed laser-based heating apparatus has been developed to provide local heating of subcutaneous tumors in order to activate release of agents from thermosensitive liposomes specifically at the tumor region.

מכשירי חימום המבוסס על לייזר מותאם אישית המיועדים לשחרור עורר, ציספלטין מThermosensitive יפוזומים עם הדרכת תמונת תהודה מגנטית

Liposomes have been employed as drug delivery systems to target solid tumors through exploitation of the enhanced permeability and retention (EPR) effect ...

Alternating Magnetic Field-Responsive Hybrid Gelatin Microgels for Controlled Drug Release

Magnetically-responsive nano/micro-engineered biomaterials that enable a tightly controlled, on-demand drug delivery have been developed as new types of smart soft devices for biomedical applications. Although a number of magnetically-responsive drug delivery systems have demonstrated efficacies through either in vitro proof of concept studies or in vivo preclinical applications, their use in clinical settings is still limited by their insufficient biocompatibility or biodegradability. Additionally, many of the existing platforms rely on sophisticated techniques for their fabrications. We recently demonstrated the fabrication of biodegradable, gelatin-based thermo-responsive microgel by physically entrapping poly(N-isopropylacrylamide-co-acrylamide) chains as a minor component within a three-dimensional gelatin network. In this study, we present a facile method to fabricate a biodegradable drug release platform that enables a magneto-thermally triggered drug release. This was achieved by incorporating superparamagnetic iron oxide nanoparticles and thermo-responsive polymers within gelatin-based colloidal microgels, in conjunction with an alternating magnetic field application system.

We present a facile method to fabricate a biodegradable gelatin-based drug release platform that is magneto-thermally responsive. This was achieved by incorporating superparamagnetic iron oxide nanoparticles and poly(N-isopropylacrylamide-co-acrylamide) within a spherical gelatin micro-network crosslinked by genipin, in conjunction with an alternating magnetic field application system.

מוני Microgels לטין היברידי שדה-Responsive המגנטי לשחרור סמים מבוקר

Magnetically-responsive nano/micro-engineered biomaterials that enable a tightly controlled, on-demand drug delivery have been developed as new types of ...

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan electron-paramagnetic-resonance (RS-EPR), which can provide quantitative information under in vivo conditions on oxygen concentration, pH, redox status and concentration of signaling molecules (i.e., OH&#8226;, NO&#8226;). The RS-EPR technique has a higher sensitivity, improved spatial resolution (1 mm), and shorter acquisition time in comparison to the standard continuous wave (CW) technique. A variety of phantom configurations have been tested, with spatial resolution varying from 1 to 6 mm, and spectral width of the reporter molecules ranging from 16 &#181;T (160 mG) to 5 mT (50 G). A cross-loop bimodal resonator decouples excitation and detection, reducing the noise, while the rapid scan effect allows more power to be input to the spin system before saturation, increasing the EPR signal. This leads to a substantially higher signal-to-noise ratio than in conventional CW EPR experiments.

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

A new electron paramagnetic resonance (EPR) method, rapid scan EPR (RS-EPR), is demonstrated for 2D spectral spatial imaging which is superior to the traditional continuous wave (CW) technique and opens new venues for in vivo imaging. Results are demonstrated at 250 MHz, but the technique is applicable at any frequency.

ראפיד סריקת אלקטרונים פאראמגנטיים תהודה פותחת אפיקים חדשים עבור פרמטרים חשובים מבחינת פיזיולוגית ההדמיה<em&gt; In vivo</em

We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan ...

Magnetic Levitation Coupled with Portable Imaging and Analysis for Disease Diagnostics

Currently, many clinical diagnostic procedures are complex, costly, inefficient, and inaccessible to a large population in the world. The requirements for specialized equipment and trained personnel require that many diagnostic tests be performed at remote, centralized clinical laboratories. Magnetic levitation is a simple yet powerful technique and can be applied to levitate cells, which are suspended in a paramagnetic solution and placed in a magnetic field, at a position determined by equilibrium between a magnetic force and a buoyancy force. Here, we present a versatile platform technology designed for point-of-care diagnostics which uses magnetic levitation coupled to microscopic imaging and automated analysis to determine the density distribution of a patient's cells as a useful diagnostic indicator. We present two platforms operating on this principle: (i) a smartphone-compatible version of the technology, where the built-in smartphone camera is used to image cells in the magnetic field and a smartphone application processes the images and to measures the density distribution of the cells and (ii) a self-contained version where a camera board is used to capture images and an embedded processing unit with attached thin-film-transistor (TFT) screen measures and displays the results. Demonstrated applications include: (i) measuring the altered distribution of a cell population with a disease phenotype compared to a healthy phenotype, which is applied to sickle cell disease diagnosis, and (ii) separation of different cell types based on their characteristic densities, which is applied to separate white blood cells from red blood cells for white blood cell cytometry. These applications, as well as future extensions of the essential density-based measurements enabled by this portable, user-friendly platform technology, will significantly enhance disease diagnostic capabilities at the point of care.

We present a magnetic levitation technique coupled with automated imaging and analysis in both a smartphone-compatible device and a device with embedded imaging and processing. This is applied to measure the density distribution of cells with two demonstrated biomedical applications: sickle cell disease diagnosis and separating white and red blood cells.

ריחוף מגנטי יחד עם הדמיה ניידת וניתוח עבור אבחון מחלות

Currently, many clinical diagnostic procedures are complex, costly, inefficient, and inaccessible to a large population in the world. The requirements for ...

Magnetic and Thermal-sensitive Poly(N-isopropylacrylamide)-based Microgels for Magnetically Triggered Controlled Release

Magnetically and thermally sensitive poly(N-isopropylacrylamide) (PNIPAAm)/Fe3O4-NH2 microgels with the encapsulated anti-cancer drug curcumin (Cur) were designed and fabricated for magnetically triggered release. PNIPAAm-based magnetic microgels with a spherical structure were produced via a temperature-induced emulsion followed with physical-crosslinking by mixing PNIPAAm, polyethylenimine (PEI), and Fe3O4-NH2 magnetic nanoparticles. Because of their dispersity, the Fe3O4-NH2 nanoparticles were embedded inside the polymer matrix. The amine groups exposed on the Fe3O4-NH2 and PEI surface supported the spherical structure by physically crosslinking with the amide groups of the PNIPAAm. The hydrophobic anti-cancer drug curcumin can be dispersed in water after encapsulation into the microgels. The microgels were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and UV-Vis spectral analysis. Furthermore, magnetically triggered release was studied under an external high frequency magnetic field (HFMF). A significant &#34;burst release&#34; of curcumin was observed after applying the HFMF to the microgels due to the magnetic inductive heating (hyperthermia) effect. This manuscript describes the magnetically triggered controlled release of Cur-PNIPAAm/Fe3O4-NH2 encapsulated curcumin, which can be potentially applied for tumor therapy.

Magnetic and Thermal-sensitive PolyN-isopropylacrylamide-based Microgels for Magnetically Triggered Controlled Release

This manuscript describes the preparation of magnetic and thermal-sensitive microgels via a temperature-induced emulsion without chemical reaction. These sensitive microgels were synthesized by mixing poly(N-isopropylacrylamide) (PNIPAAm), polyethylenimine (PEI) and Fe3O4-NH2 nanoparticles for the potential use in magnetically and thermally triggered drug-release.

מגנטי תרמי רגיש פולי (<em&gt; N</em&gt; -isopropylacrylamide) מבוססי microgels עבור מגנטית מופעל מבוקר שחרור

Magnetically and thermally sensitive poly(N-isopropylacrylamide) (PNIPAAm)/Fe3O4-NH2 microgels with the encapsulated anti-cancer drug curcumin (Cur) were ...

Metabolic Support of Excised, Living Brain Tissues During Magnetic Resonance Microscopy Acquisition

This protocol describes the procedures necessary to support normal metabolic functions of acute brain slice preparations during the collection of magnetic resonance (MR) microscopy data. While it is possible to perform MR collections on living, excised mammalian tissue, such experiments have traditionally been constrained by resolution limits and are thus incapable of visualizing tissue microstructure. Conversely, MR protocols that did achieve microscopic image resolution required the use of fixed samples to accommodate the need for static, unchanging conditions over lengthy scan times. The current protocol describes the first available MR technique that enables imaging of living, mammalian tissue samples at microscopic resolutions. Such data is of great importance to the understanding of how pathology-based contrast changes occurring at the microscopic level influence the content of macroscopic MR scans such as those used in the clinic. Once such an understanding is realized, diagnostic methods with greater sensitivity and accuracy can be developed, which will translate directly to earlier disease treatment, more accurate therapy monitoring and improved patient outcomes.
While the described methodology focuses on brain slice preparations, the protocol is adaptable to any excised tissue slice given that changes are made to the gas and perfusate preparations to accommodate the tissue&#39;s specific metabolic needs. Successful execution of the protocol should result in living, acute slice preparations that exhibit MR diffusion signal stability for periods up to 15.5 h. The primary advantages of the current system over other MR compatible perfusion apparatuses are its compatibility with the MR microscopy hardware required to attain higher resolution images and ability to provide constant, uninterrupted flow with carefully regulated perfusate conditions. Reduced sample throughput is a consideration with this design as only one tissue slice may be imaged at a time.

The current protocol describes a method by which users can maintain viability of acute hippocampal and cortical slice preparations during the collection of magnetic resonance microscopy data.

תמיכה מטבולית של טוחנות, חי ברקמות המוח במהלך רכישת מיקרוסקופ תהודה מגנטית

This protocol describes the procedures necessary to support normal metabolic functions of acute brain slice preparations during the collection of magnetic ...

Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate

The fundamental limit to in vivo imaging applications of hyperpolarized 13C-enriched compounds is their finite spin-lattice relaxation times. Various factors affect the relaxation rates, such as buffer composition, solution pH, temperature, and magnetic field. In this last regard, the spin-lattice relaxation time can be measured at clinical field strengths, but at lower fields, where these compounds are dispensed from the polarizer and transported to the MRI, the relaxation is even faster and difficult to measure. To have a better understanding of the amount of magnetization lost during transport, we used fast field-cycling relaxometry, with magnetic resonance detection of 13C nuclei at ~0.75 T, to measure the nuclear magnetic resonance dispersion of the spin-lattice relaxation time of hyperpolarized [1-13C]pyruvate. Dissolution dynamic nuclear polarization was used to produce hyperpolarized samples of pyruvate at a concentration of 80 mmol/L and physiological pH (~7.8). These solutions were rapidly transferred to a fast field-cycling relaxometer so that relaxation of the sample magnetization could be measured as a function of time using a calibrated small flip angle (3&#176;-5&#176;). To map the T1 dispersion of the C-1 of pyruvate, we recorded data for different relaxation fields ranging between 0.237 mT and 0.705 T. With this information, we determined an empirical equation to estimate the spin-lattice relaxation of the hyperpolarized substrate within the mentioned range of magnetic fields. These results can be used to predict the amount of magnetization lost during transport and to improve experimental designs to minimize signal loss.

Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate

We present a protocol to measure the magnetic field dependence of the spin-lattice relaxation time of 13C-enriched compounds, hyperpolarized by means of dynamic nuclear polarization, using fast field-cycled relaxometry. Specifically, we have demonstrated this with [1-13C]pyruvate, but the protocol could be extended to other hyperpolarized substrates.

מדידת רשת ספין-סריג הרפיה השדה המגנטי של היפרקוטב [1-13ג] פיבט

The fundamental limit to in vivo imaging applications of hyperpolarized 13C-enriched compounds is their finite spin-lattice relaxation times. Various ...

High-resolution Imaging of Nuclear Dynamics in Live Cells under Uniaxial Tensile Strain

Extracellular mechanical strain is known to elicit cell phenotypic responses and has physiological relevance in several tissue systems. To capture the effect of applied extracellular tensile strain on cell populations in vitro via biochemical assays, a device has previously been designed which can be fabricated simply and is small enough to fit inside tissue culture incubators, as well as on top of microscope stages. However, the previous design of the polydimethylsiloxane substratum did not allow high-resolution subcellular imaging via oil-immersion objectives. This work describes a redesigned geometry of the polydimethylsiloxane substratum and a customized imaging setup that together can facilitate high-resolution subcellular imaging of live cells while under applied strain. This substratum can be used with the same, earlier designed device and, hence, has the same advantages as listed above, in addition to allowing high-resolution optical imaging. The design of the polydimethylsiloxane substratum can be improved by incorporating a grid which will facilitate tracking the same cell before and after the application of strain. Representative results demonstrate high-resolution time-lapse imaging of fluorescently labeled nuclei within strained cells captured using the method described here. These nuclear dynamics data give insights into the mechanism by which applied tensile strain promotes differentiation of oligodendrocyte progenitor cells.&#160;

Using a previously designed device to apply mechanical strain to adherent cells, this paper describes a redesigned substratum geometry and a customized apparatus for high-resolution single-cell imaging of strained cells with a 100x oil immersion objective.

ברזולוציה גבוהה הדמיה של דינמיקה גרעינית בתאים חיים תחת מתיחה Uniaxial המתח

Extracellular mechanical strain is known to elicit cell phenotypic responses and has physiological relevance in several tissue systems. To capture the ...