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Full-Text Articles in Engineering Science and Materials

Dynamics In Polymer Nanocomposites Containing Fixed And Mobile Nanoparticles, Chia-Chun Lin Jan 2015

Dynamics In Polymer Nanocomposites Containing Fixed And Mobile Nanoparticles, Chia-Chun Lin

Publicly Accessible Penn Dissertations

This dissertation describes experimental studies on the dynamics of polymer nanocomposites (PNC), namely, center-of-mass (COM) polymer diffusion in PNCs, and COM nanoparticle (NP) diffusion in polymer melts. Elastic recoil detection (ERD) is used for polymer diffusion studies and Rutherford backscattering (RBS) is used for NP diffusion studies. Diffusion of the tracer polymer, deuterated poly(methyl methacrylate) (dPMMA) is slowed down in a PMMA matrix filled with hydroxyl-capped spherical silica nanoparticles. A confinement parameter, ID/2Rg, where ID is interparticle distance and 2Rg is probe size is defined to account for the NP crowding effect. For highly crowded region where ID ...


Multifunctional Nanomaterials Of Dna Block Copolymers: Synthesis, Self- Assembly, Thermodynamic Studies And Biomedical Applications, Xi-Jun Chen Jan 2013

Multifunctional Nanomaterials Of Dna Block Copolymers: Synthesis, Self- Assembly, Thermodynamic Studies And Biomedical Applications, Xi-Jun Chen

Publicly Accessible Penn Dissertations

Oligonucleotide-conjugated bio-hybrid nanomaterials with a dense DNA layer on the surface have been shown to possess extraordinary selectivity and sensitivity for DNA detection as well as promising results as delivery agents, as demonstrated with the exceptional example of polyvalent oligonucleotide-conjugated gold nanoparticles. However, progress in this field has been slowed, since achieving high DNA density functionalization on the nanoparticle surface for materials other than gold is a major challenge. In this body of work, we have developed a general system to conjugate a dense layer of DNA on the surface of nanoparticles by the self-assembly of DNA block copolymer. These ...


Injectable Hydrogels For Local Protein Delivery To Engineer Myocardial Remodeling, Brendan Patrick Purcell Jan 2013

Injectable Hydrogels For Local Protein Delivery To Engineer Myocardial Remodeling, Brendan Patrick Purcell

Publicly Accessible Penn Dissertations

The endogenous tissue remodeling events that occur following a myocardial infarction (MI) are inadequate to maintain left ventricular (LV) function, and the progression towards heart failure is often inevitable. Our increased understanding of protein regulators of post MI remodeling provides the opportunity to intervene and engineer tissue remodeling through exogenous protein delivery. The global hypothesis of this dissertation was that the local delivery of therapeutic proteins (SDF-1alpha and TIMP-3) from injectable hyaluronic acid (HA) hydrogels attenuates adverse post MI remodeling processes by providing sustained concentrations of bioactive signals within the remodeling myocardium.

To test this hypothesis, HA based hydrogels were ...