Name: a facile and eco-friendly route to fabricate poly(lactic acid) scaffolds with graded pore size
Uploaded: 2016-10-17T13:00:00
Description: Watch this Scientific Journal Video about A Facile and Eco-friendly Route to Fabricate PolyLactic Acid Scaffolds with Graded Pore Size at JoVE.com

This work was financially supported by INSTM.

ייצור פיגום 1. <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> טוחני NaCl בבלנדר במעבדה במשך 20 דקות ולייבש אותו על תנור ב 100 מעלות צלזיוס. </li><li style=";text-align:right;direction:rtl"> שים את NaCl היבש (45 גרם בשלב) במכונת סינון במשך 30 דקות בתדירות הגבוהה ביותר הקיימת ללא ההתרחש תהודה. אסוף ש?...

<ol>
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השלב הקריטי הראשון הוא אופטימיזציה של סינון יעיל. השליטה הגבוהה של גודל חלקיקי NaCl היא יסוד להכנת פיגום עם התפלגות גודל הנקבובי רצויה. עוד צעד קריטי הוא הימנעות השבר של monolayers PLA הרזה במהלך חילוץ המדגם מהתבנית. ניתוח עיבוד תמונה לא יכול להיות נציג של המכשיר כולו. <p class=...

The interest in biodegradable polymers has grown in importance during the last years both in academia and in the industry, due to the rising concerns regarding plastic waste and the reduction in using non-renewable sources1-7. In particular, biocompatible and biodegradable synthetic polymers are widespread in several biomedical application fields, such as drug controlled release8,9, absorbable suture threads8,10, bioprocess intensification11 and tissue engineering12.
Tissue engineering focuses on the development of devices capable to restore and maintain normal function in diseased or injured tissues. Most of the native tissues are composed by different types of cells and extracellular matrices (ECMs) in specific spatial hierarchies. For example, articular cartilage (AC) consists of different zones with varying types and orientations of collagen fibers and collagen-binding proteins. Moreover, cartilage and bone show significantly different hierarchical structures. In this context, the preparation of multilayer scaffolds with engineered properties in each layer could allow replacing heterogeneous tissues by taking into accounts all the local microenvironments of these complex systems13,14.
Based on the cellular/biological and/or physical-chemical characteristics of the scaffolds, the main strategies adopted by the tissue engineering can be divided into monophasic, biphasic, and triphasic. Biphasic and triphasic approaches (BTA) use two or three different pores architectures, materials, or fillers to prepare multilayered functional devices. Furthermore, a single material can be used to achieve biphasic or triphasic devices, as long as it is possible to create a gradient in its physical properties12.
Cell migration plays a key-role in the morphogenesis, inflammation, wound healing and tumor metastasis. Cell movement is encouraged by the presence of a gradient of chemical-physical properties from the surface to the core of the device. Therefore, biomaterials fulfilling the above discussed requirements can be helpful in studying cell migration. In addition to chemical gradients that trigger cells migration (chemotaxis), mechanical properties of cells culture substrate can also lead to cell movement (mechanotaxis)15.
The multilayer structure can also provide the tunable release of specific drugs incorporated within the polymer matrix, by changing the specific area of the layer or the amount of loaded drugs. 
Over the past decade, in order to develop scaffolds possessing a discrete or continuous gradient of morphological properties, such as porosity or pore size, several approaches have been presented16-31. The most recent papers focused on the preparation of BTA by adopting: particle leaching 12,28,32, gas foaming technique16, electrospinning17-19, layer by layer casting technique20, rapid prototyping21,22, thermally induced phase separation (TIPS)22, centrifugation freeze drying24,25, triply periodic minimal surfaces (TPMS)26, freeze casting27-30.
Within the frame of this work, we present a fast and simple route to achieve PLA-based three-layer porous scaffolds (TLS), by combining melt mixing, compression molding and salt leaching. Differently from most of the technologies commonly used for scaffold production, the strategy herein adopted can be considered fully eco-friendly, since it does not require any toxic solvent potentially dangerous for environment and for living cells and tissues32. The basic processing-structure-property relationships established in this study by analyzing both morphological features and mechanical behavior of fabricated devices provide guidance to future advances in designing multifunctional graded scaffolds with specific target properties.

<table border="0" cellpadding="0" cellspacing="0" width="828">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Poly(lactic acid)</td>
			<td style="width:149px;">NatureWorks</td>
			<td style="width:207px;">PLA 2002D</td>
			<td style="width:257px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Poly(ethylene glycol)</td>
			<td style="width:149px;">Sigma</td>
			<td style="width:207px;">83797-1KG-F</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sodium Cloride</td>
			<td style="width:149px;">Sigma</td>
			<td style="width:207px;">793566-5KG-D</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Phosfate Buffer Solution</td>
			<td style="width:149px;">Sigma</td>
			<td style="width:207px;">P5368-10PAK</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Laboratory Mixer</td>
			<td style="width:149px;">Brabender</td>
			<td style="width:207px;">PLE 330 - Plasticorder</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Laboratory Press</td>
			<td style="width:149px;">Carver</td>
			<td style="width:207px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Scanning Electron Microscopy</td>
			<td style="width:149px;">Phenom-world</td>
			<td style="width:207px;">ProX</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Universal Testing Machine</td>
			<td style="width:149px;">Instron</td>
			<td style="width:207px;">3365 (UK)</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">BioPuls Bath</td>
			<td style="width:149px;">Instron, Norwood</td>
			<td style="width:207px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sieving Machine</td>
			<td style="width:149px;">Endecotts</td>
			<td style="width:207px;">E.V.F.1.</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Vacuum Oven</td>
			<td style="width:149px;">ISCO</td>
			<td style="width:207px;">NSV9035</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Precision Balance</td>
			<td style="width:149px;">Sartorius</td>
			<td style="width:207px;">AX224</td>
			<td></td>
		</tr>
	</tbody>
</table>

a facile and eco-friendly route to fabricate poly(lactic acid) scaffolds with graded pore size

Over the recent years, functionally graded scaffolds (FGS) gaineda crucial role for manufacturing of devices for tissue engineering. The importance of this new field of biomaterials research is due to the necessity to develop implants capable of mimicking the complex functionality of the various tissues, including a continuous change from one structure or composition to another. In this latter context, one topic of main interest concerns the design of appropriate scaffolds for bone-cartilage interface tissue. In this study, three-layered scaffolds with graded pore size were achieved by melt mixing poly(lactic acid) (PLA), sodium chloride (NaCl) and polyethylene glycol (PEG). Pore size distributions were controlled by NaCl granulometry and PEG solvation. Scaffolds were characterized from a morphological and mechanical point of view. A correlation between the preparation method, the pore architecture and compressive mechanical behavior was found. The interface adhesion strength was quantitatively evaluated by using a custom-designed interfacial strength test. Furthermore, in order to imitate the human physiology, mechanical tests were also performed in phosphate buffered saline (PBS) solution at 37 &#176;C. The method herein presented provides a high control of porosity, pore size distribution and mechanical performance, thus offering the possibility to fabricate three-layered scaffolds with tailored properties by following a simple and eco-friendly route.

השפעת גודל חלקיקי NaCl על הארכיטקטורה הנקבובית של הפיגומים הוערכה איכותית וכמותית על ידי חוקר את המורפולוגיה של הדגימות וחישוב התפלגות הגודל הנקבובי על ידי ניתוח תמונה, בהתאמה איור 2a -. F תערוכות micrographs SEM של פיגומים מונו-שכבתי וכתוצ?...

Watch this Scientific Journal Video about A Facile and Eco-friendly Route to Fabricate PolyLactic Acid Scaffolds with Graded Pore Size at JoVE.com

A Facile and Eco-friendly Route to Fabricate PolyLactic Acid Scaffolds with Graded Pore Size

In this work, poly(lactic acid)/polyethylene glycol (PLA/PEG) scaffolds were prepared by using a combination of melt mixing and selective leaching. The method herein discussed permitted to develop three-layer scaffolds by highly controlling both porosity and pore size. The mechanical properties were also evaluated in a physiological environment.

קליל ידידותי לסביבת כביש לפברק פולי (החומצה לקטית) פיגומים עם גודל מדורג נקבובי

Over the recent years, functionally graded scaffolds (FGS) gaineda crucial role for manufacturing of devices for tissue engineering. The importance of ...

Research

JoVE Journal

Bioengineering

A Facile and Eco-friendly Route to Fabricate Poly(Lactic Acid) Scaffolds with Graded Pore Size

Micropatterned Surfaces to Study Hyaluronic Acid Interactions with Cancer Cells

משטחים micropatterned לחקר אינטראקציות חומצה היאלורונית עם תאים סרטניים

Cancer invasion and progression involves a motile cell phenotype, which is under complex regulation by growth factors/cytokines and extracellular matrix ...

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

עיצוב של bioreactor לחץ על מחזורי Ex Vivo מחקר של מסתמי הלב אבי העורקים

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic ...

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

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 ...

Multi-Scale Modification of Metallic Implants With Pore Gradients, Polyelectrolytes and Their Indirect Monitoring In vivo

Multi-Scale Modification of Metallic Implants With Pore Gradients, Polyelectrolytes and Their Indirect Monitoring In vivo

שינוי רב היקף של שתלים מתכתיים עם מילויים נקבוביים, Polyelectrolytes וניטורם העקיף<em&gt; בvivo</em

Metallic implants, especially titanium implants, are widely used in  clinical applications. Tissue in-growth and integration to these implants in  the ...

Microfluidic Fabrication of Polymeric and Biohybrid Fibers with Predesigned Size and Shape

ייצור מיקרופלואידי של סיבים פולימריים וביוהיברידים עם גודל וצורה מעוצבים מראש

A &#8220;sheath&#8221; fluid passing through a microfluidic channel at low Reynolds number can be directed around another &#8220;core&#8221; stream and ...

Electrospun Nanofiber Scaffolds with Gradations in Fiber Organization

Electrospun nanofiber פיגומים עם דרגות בארגון סיבים

The goal of this protocol is to report a simple method for generating nanofiber scaffolds with gradations in fiber organization and test their possible ...

A Microfluidic Platform for Precision Small-volume Sample Processing and Its Use to Size Separate Biological Particles with an Acoustic Microdevice

פלטפורמת microfluidic לעיבוד מדגם Precision הקטן-נפח ושימוש בו לגודל חלקיקים הביולוגיים נפרדים עם Microdevice אקוסטי

A major advantage of microfluidic devices is the ability to manipulate small sample volumes, thus reducing reagent waste and preserving precious sample. ...

Sustained Administration of &#946;-cell Mitogens to Intact Mouse Islets Ex Vivo Using Biodegradable Poly(lactic-co-glycolic acid) Microspheres

Sustained Administration of ÃƒÆ’Ã…Â½Ãƒâ€šÃ‚Â²-cell Mitogens to Intact Mouse Islets Ex Vivo Using Biodegradable Polylactic-co-glycolic acid Microspheres

מנהל מתמשך של mitogens β-cell כדי איי עכבר Intact<em&gt; Ex Vivo</em&gt; שימוש פוליפוני מתכלה (לקטית-שיתוף גליקולית וחומצה) מיקרוסכמות

The development of biomaterials has significantly increased the potential for targeted drug delivery to a variety of cell and tissue types, including the ...

An Additive Manufacturing Technique for the Facile and Rapid Fabrication of Hydrogel-based Micromachines with Magnetically Responsive Components

תוסף טכניקת הייצור עבור הזיוף נתיישב ומהירה של מבוססי הידרוג Micromachines עם רכיבים תגובה מגנטית

Polyethylene glycol (PEG)-based hydrogels are biocompatible hydrogels that have been approved for use in humans by the FDA. Typical PEG-based hydrogels ...

Human Pluripotent Stem Cell Culture on Polyvinyl Alcohol-Co-Itaconic Acid Hydrogels with Varying Stiffness Under Xeno-Free Conditions

התרבות תאי גזע Pluripotent אנושי על פוליויניל אלכוהול-Co-Itaconic Hydrogels חומצה עם קשיות שונות בתנאים קסנו-חופשית

The effect of physical cues, such as the stiffness of biomaterials on the proliferation and differentiation of stem cells, has been investigated by ...