Posts Tagged ‘Polymer’

HEMA Incorporated in Tissue Engineering Scaffolds

Monday, January 24th, 2011
Share This Post!

Modification of polymer networks with bone sialoprotein promotes cell attachment and spreading

Wailen D. Chan, Harvey A. Goldberg, Graeme K. Hunter, S. J. Dixon,  Amin S. Rizkalla, Journal of Biomedical Materials Research Part A

ABSTRACT:

Biomaterials used for tissue engineering scaffolds act as temporary substrates, on which cells deposit newly synthesized extracellular matrix. In cartilage tissue engineering, polycaprolactone/poly(2-hydroxyethyl methacrylate) (PCL/pHEMA) polymer blends have been used as scaffold materials, but their use in osseous tissue engineering has been more limited. The objective of this study was to evaluate modification of PCL/pHEMA surfaces with bone sialoprotein (BSP), an extracellular matrix protein important in regulating osseous tissue formation. Modification of surfaces with BSP significantly enhanced osteoblastic cell attachment and spreading, without compromising proliferation. Thus, BSP-immobilization may be a useful strategy for optimizing scaffolds for skeletal tissue engineering.

INTRODUCTION:

Tissue regeneration requires a substrate that allows cells to adhere, proliferate, and eventually form their own matrix. Polymers from the polyester family, such as poly(lactic acid), poly(glycolic acid), or their copolymers, have been the most commonly used materials to fabricate scaffolds for skeletal tissue engineering applications.  More recently, another member of this family, poly(ε-caprolactone) (PCL) has also been considered for skeletal tissue engineering. Human primary osteoblasts demonstrate attachment and spreading on PCL surfaces.

Poly(2-hydroxyethyl methacrylate) (pHEMA) is another polymer that has been used extensively as a biomaterial in drug delivery and soft-tissue applications. pHEMA gels have a propensity to calcify after prolonged implantation periods, leading to the suggestion that pHEMA could be used for filling bone or dental defects…

PREPARATION:

PCL/pHEMA semi-interpenetrating networks (sIPN’s) were prepared by combining HEMA monomer (Esstech, Essington, PA), a low-molecular-weight PCL (CAPA 2302, 3000 g/mol; Solvay Interox, Warrington, UK), and a high-molecular-weight PCL (CAPA 6506, 50,000 g/mol; Solvay Interox) in a 5.5:2.5:1 weight ratio, respectively. PCL and HEMA monomer were mixed together and placed in an oven at 60oC to facilitate melting and dissolution of PCL in HEMA monomer. After melting, the compositions were thoroughly mixed to ensure a homogenous distribution. Camphorquinone (Esstech) was added to the mixtures at 0.2% by weight of HEMA monomer. The mixtures were sonicated for approximately 8 min to evenly dissolve the camphorquinone. 1 mL polypropylene syringes (∼4 mm internal diameter) were subsequently filled with PCL/HEMA monomer compositions and cured using a Triad 2000 light-curing system (Dentsply, York, PA).


Article first published online: 31 MAR 2010, DOI:  10.1002/jbm.a.32715, Copyright 2010 Wiley Periodicals, Inc.

Volume 94A, Issue 3, pages 945–952, 1 September 2010

Link:  http://onlinelibrary.wiley.com/doi/10.1002/jbm.a.32715/abstract


Share This Post!

Refractive Index of Methacrylate Monomers & Polymers

Thursday, March 11th, 2010
Share This Post!

TECHNICAL BULLETIN:  Refractive Index of Monomers and Their Respective Polymers

The refractive index (RI) of photopolymers is an essential property for many applications.  For optical and coating applications, the RI can be related to the resultant gloss or clarity upon cure.  Within the dental industry, the refractive index of the organic polymer matrix, must match that of the inorganic filler and substrate in order to avoid obvious “lines” where the product is applied.

Various factors affect refractive index values.  The presence of conjugated ring structures contributes to increasing RI.  In general, larger molecular weight monomers have a tendency to possess a higher RI in comparison to their lower molecular weight counterparts.  Similar to this trend, high molecular weight functional groups like methacrylates have higher RI than their acrylate counterparts. Higher atomic weight atoms also seem to be predisposed to having higher RI.

Recognizing the importance of refractive index to our customers, Esstech has assembled RI data for a portion of our existing monomer products as well as their corresponding homopolymers.

 Esstech Refractive Index Chart

Maintaining its position as an industry innovator, Esstech has also created functional, high refractive index materials.  Contact us to learn more about these novel materials and how Esstech can make a material to match your application.

 (P) 800-245-3800 / (P) 610-521-3800 / techsupport@esstechinc.com / www.esstechinc.com


Share This Post!

Esstech Inc. – Creating custom products & formulations to meet your unique needs!