Geometric Modeling of Cellular Materials for Additive Manufacturing in Biomedical Field: A Review

Advances in additive manufacturing technologies facilitate the fabrication of cellular materials that have tailored functional characteristics. The application of solid freeform fabrication techniques is especially exploited in designing scaffolds for tissue engineering. In this review, firstly, a classification of cellular materials from a geometric point of view is proposed; then, the main approaches on geometric modeling of cellular materials are discussed. Finally, an investigation on porous scaffolds fabricated by additive manufacturing technologies is pointed out. Perspectives in geometric modeling of scaffolds for tissue engineering are also proposed

Multi-scale cellular engineering: From molecules to organ-on-a-chip.

Recent technological advances in cellular and molecular engineering have provided new insights into biology and enabled the design, manufacturing, and manipulation of complex living systems. Here, we summarize the state of advances at the molecular, cellular, and multi-cellular levels using experimental and computational tools. The areas of focus include intrinsically disordered proteins, synthetic proteins, spatiotemporally dynamic extracellular matrices, organ-on-a-chip approaches, and computational modeling, which all have tremendous potential for advancing fundamental and translational science. Perspectives on the current limitations and future directions are also described, with the goal of stimulating interest to overcome these hurdles using multi-disciplinary approaches

Molecularly Engineered Self-Assembling Membranes for Cell-Mediated Degradation

The use of peptide engineering to develop self-assembling membranes that are responsive to cellular enzyme activities is reported. The membranes are obtained by combining hyaluronan (HA) and a rationally designed peptide amphiphile (PA) containing a proteolytic domain (GPQGIWGQ octapeptide) sensitive to matrix metalloproteinase-1 (MMP-1). Insertion of an octapeptide in a typical PA structure does not disturb its self-assembly into fibrillar nanostructures neither the ability to form membranes with HA. In vitro enzymatic degradation with hyaluronidase and MMP-1 shows that membranes containing the MMP-1 substrate exhibit enhanced enzymatic degradation, compared with control membranes (absence of MMP-1 cleavable peptide or containing a MMP-1 insensitive sequence), being completely degraded after 7 days. Cell viability and proliferation is minimally affected by the enzymatically cleavable functionality of the membrane, but the presence of MMP-1 cleavable sequence does stimulate the secretion of MMP-1 by fibroblasts and interfere with matrix deposition, particularly the deposition of collagen. By showing cell-responsiveness to biochemical signals presented on self-assembling membranes, this study highlights the ability of modulating certain cellular activities through matrix engineering. This concept can be further explored to understand the cellular remodeling process and as a strategy to develop artificial matrices with more biomimetic degradation for tissue engineering applications.This work was funded by the European Regional Development Fund (ERDF) through the Operational Competitiveness Programme "COMPETE" (FCOMP-01-0124-FEDER-014758) and national funds through the Portuguese Foundation for Science and Technology (FCT) under the project PTDC/EBB-BIO/114523/2009. The authors also thank a start-up grant provided by the School of Engineering and Materials Science at QMUL. D.S.F. gratefully acknowledges FCT for the PhD scholarship (SFRH/BD/44977/2008)

Cellular responses to external mechanical stimuli when seeded to 3D collagen

INTRODUCTION: Collagen is a naturally occurring visco-elastic protein and widely used biomaterial in Tissue engineering. Mechanical stimulation of cell seeded collagen constructs and its effects on cell orientation, intracellular signalling and molecular responses have been reported in literature2. Monitoring of cellular responses to mechanical stimulation include synthesis of active regulatory molecules such as growth factors or hormones, changes in matrix synthesis, cell alignment and enzyme release. The aim of this study was to investigate cellular responses to pre strained, stiffer and more organised collagen bio-artificial matrices

Gold Nanoparticles and Its Potential Applications in Cancer Research

2009 Spring Meeting of the NANOFANS Forum. Presented on May 1, 2009 from 11 am-2 pm in the Marcus Nanotechnology Building (Rooms 1116-1118) on the Georgia Tech campus.Cancer Nanotechnology: New Opportunities in Engineering and Medicine / Shuming Nie, Director, Center of Cancer Nanotechnology Excellence, Emory and Georgia Tech -- Magnetic Nanoparticles and Ovarian Cancer: A Potential New Direction in Therapeutic Intervention / John McDonald, Director, Ovarian Cancer Institute and Chair of the School of Biology at Georgia Tech -- Gold Nanoparticles and Its Potential Applications in Cancer Research / Mostafa El-Sayed, Director, Laser Dynamics Laboratory at the School of Chemistry & Biochemistry at Georgia Tech.Shuming Nie is the Wallace H. Coulter Distinguished Chair Professor in Biomedical Engineering at Emory University and the Georgia Institute of Technology. His research interest is broadly in biomolecular engineering and nanotechnology. John McDonald is taking an integrated systems approach to the study of cancer. This means that he views cancer not as a defect in any particular gene or protein, but as a de-regulated cellular/ inter-cellular process. Mostafa El-Sayed is the Julius Brown Chair and Regents Professor in the School of Chemistry and Biochemistry at Georgia Tech. He researches Nanoscience and also investigates how Nanoparticles can be used in Nanomedicine, Nano Catalysis, and Nanophotonics