Wednesday, February 13, 2013

mPEG-PCL, PCL-PEG-PCL thermogels

In addition to PLGA/PEG based thermogels such as AK12 and AK24, PolySciTech also carries PCL/PEG based thermogels. These include AK35 (PCL-PEG-PCL triblock) and AK36 (mPEG-PCL diblock).
These perform a little differently than the PLGA-PEG-PLGA blocks.  Traditionally the AK12 and AK24 polymers dissolve over the course of 2-3 days with shaking or stirring at low temperature (5C) to become clear, water-like, solutions.  Due to increased hydrophobicity/crystallinity the PCL based thermogels AK35 and AK36 require, in addition to 2-3 days of shaking at low temperture, about 30minutes of stirring at a high temperature (80C) to fully dissolve.  Afterwards upon recooling the material forms into an opaque solution which shows increased gelation (notable rise in G'/G") upon warming.

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NOTE: mPEG-PCL (AK036) thermogelation properties vary depending on storage time and also conditions such as warming, etc. which lead to self-crystallization of the PCL chains. This material may work as a thermogel but its performance is unreliable. If the batch you have is not thermogelling dissolve in organic solvent (DCM) and dry off quickly to reset polymer chain configuration.  
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