Carl G. Simon

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Calcium phosphate cement (CPC) sets in situ to form solid hydroxyapatite, can conform to complex cavity shapes without machining, has excellent osteoconductivity, and is able to be resorbed and replaced by new bone. Therefore, CPC is promising for craniofacial and orthopaedic repairs. However, its low strength and lack of macroporosity limit its use. This(More)
A high-throughput method for analyzing cellular response to crystallinity in a polymer material is presented. Variations in crystallinity lead to changes in surface roughness on nanometer length scales, and it is shown that cells are exquisitely sensitive to these changes. Gradients of polymer crystallinity were fabricated on films of poly(L-lactic acid)(More)
Calcium phosphate cement (CPC) self-hardens to form hydroxyapatite, has excellent osteoconductivity and bone-replacement ability, and is promising for craniofacial and orthopedic repair. However, its low strength limits CPC to only nonstress repairs. This study aimed to reinforce CPC with meshes to increase strength, and to form macropores in CPC for bone(More)
Proliferation and differentiation of cells are known to be influenced by the physical properties of the extracellular environment. Previous studies examining biophysics underlying cell response to matrix stiffness utilized a two-dimensional (2D) culture format, which is not representative of the three-dimensional (3D) tissue environment in vivo. We report(More)
OBJECTIVES Seven million people suffer bone fractures each year in the U.S., and musculoskeletal conditions cost $215 billion/year. The objectives of this study were to develop moldable/injectable, mechanically strong and in situ-hardening calcium phosphate cement (CPC) composite scaffolds for bone regeneration and delivery of osteogenic cells and growth(More)
Calcium phosphate cement (CPC) sets in situ to form resorbable hydroxyapatite and is promising for orthopaedic applications. However, it requires on-site powder-liquid mixing during surgery, which prolongs surgical time and raises concerns of inhomogeneous mixing. The objective of this study was to develop a premixed CPC scaffold with macropores suitable(More)
We have explored the use of X-ray microcomputed tomography (microCT) for assessing cell adhesion and proliferation in polymer scaffolds. Common methods for examining cells in scaffolds include fluorescence microscopy and soluble assays for cell components such as enzymes, protein or DNA. Fluorescence microscopy is generally qualitative and cannot visualize(More)
We have studied the effects of short-chain ceramides on platelet structure and function. N-Acetylsphingosine (C2-ceramide), a cell-permeable short-chain analogue, and N-acetyldihydrosphingosine (C2-dihydroceramide), which lacks the 4-5 double bond, have been investigated. C2-Ceramide (15 microM) inhibited ADP-induced aggregation by 50% at a platelet(More)
In order to accelerate tissue-engineering research, a combinatorial approach for investigating the effect of surface energy on cell response has been developed. Surface energy is a fundamental material property that can influence cell behavior. Gradients in surface energy were created by using an automated stage to decelerate a glass slide coated with a(More)
Calcium phosphate cement (CPC) sets in situ to form hydroxyapatite and is highly promising for a wide range of clinical applications. However, its low strength limits its use to only non-stress applications, and its lack of macroporosity hinders cell infiltration, bone ingrowth and implant fixation. The aim of this study was to develop strong and(More)