There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

http://nathan.instras.com/ResearchProposalDB/doc-109.pdf

A review on polymer nanofibers by electrospinning and their applications in nanocomposites

Hydrogels for tissue engineering: scaffold design variables and applications.

Electrospinning: a fascinating fiber fabrication technique.

Electrospinning is a highly versatile method to process solutions or melts, mainly of polymers, into continuous fibers with diameters ranging from a few micrometers to a few nanometers. This technique is applicable to virtually every soluble or fusible polymer. The polymers can be chemically modified and can also be tailored with additives ranging from simple carbon-black particles to complex species such as enzymes, viruses, and bacteria. Electrospinning appears to be straightforward, but is a rather intricate process that depends on a multitude of molecular, process, and technical parameters. The method provides access to entirely new materials, which may have complex chemical structures. Electrospinning is not only a focus of intense academic investigation; the technique is already being applied in many technological areas.

Electrospinning: A Fascinating Method for the Preparation of Ultrathin Fibers

The present disclosure provides spun fibers of proteins useful for the fibers, fiber networks and nonwoven fabrics for medical use, with these materials characterized by good biocompatibility properties (e.g., low tendency toward thromboses and inflammation when implanted into a human or animal). These materials can be fabricated from gelatin, collagen or elastin-mimetic proteins, functionalized proteins of the foregoing types, crosslinked functionalized proteins of the foregoing types, and there may be incorporated nonproteinaceous polymers and/or therapeutic proteins or other medicinal compounds. Additionally, there may be living cells colonized on the material of the present invention or living cells may be incorporated during the fabrication process. These materials can be used in medical applications including, without limitation, vascular grafts, reinforcement of injured tissue, wound healing, artificial organs and tissues, prosthetic heart valves and prosthetic ureters.

Native protein mimetic fibers, fiber networks and fabrics for medical use

Type I collagen-PEO fibers and non-woven fiber networks were produced by the electrospinning of a weak acid solution of purified collagen at ambient temperature and pressure. As determined by high-resolution SEM and TEM, fiber morphology was influenced by solution viscosity, conductivity, and flow rate. Uniform fibers with a diameter range of 100-150 nm were produced from a 2-wt% solution of collagen-PEO at a flow rate of 100 μl min-1. Ultimate tensile strength and elastic modulus of the resulting non-woven fabrics was dependent upon the chosen weight ratio of the collagen-PEO blend. 1H NMR dipolar magnetization transfer analysis suggested that the superior mechanical properties, observed for collagen-PEO blends of weight ratio 1 : 1, were due to the maximization of intermolecular interactions between the PEO and collagen components. The process outlined herein provides a convenient, non-toxic, non-denaturing approach for the generation collagen-containing nanofibers and non-woven fabrics that have potent...

Engineered collagen-PEO nanofibers and fabrics.

http://chaikoflab.org/wp-content/uploads/2012/07/10.pdf

Photo-cross-linking of type I collagen gels in the presence of smooth muscle cells: mechanical properties, cell viability, and function

http://chaikoflab.org/wp-content/uploads/2012/07/3.pdf

Viscoelastic and mechanical behavior of recombinant protein elastomers.

Solid-state cross-linking of elastin-mimetic fibers was investigated. Through available lysine residues, an elastin-mimetic protein polymer, poly((Val-Pro-Gly-Val-Gly)4(Val-Pro-Gly-Lys-Gly))39, was modified to incorporate an acrylate moiety. The degree of acrylate functionalization could be varied by changing the reactant ratio of anhydride to elastin. Acrylate modified elastomeric (AME) proteins were associated with lower inverse transition temperatures than the unmodified recombinant protein. The inverse transition temperature in turn dictated the temperature for fiber formation. Fibers and fabric samples of AME were prepared by electrospinning at appropriate temperatures and cross-linked by visible- light-mediated photoirradiation. Fibers in the diameter range of 300 nm-1.5 Im were produced. Fabrics were found to have an average pore size of 78 Im. The occurrence of cross-linking was confirmed by 13 C solid-state NMR with a commensurate increase in modulus.

/pdf/photomediated-solid-state-cross-linking-of-an-elastin-22zbkzb0tr.pdf

Karthik Nagapudi

Papers

Native protein mimetic fibers, fiber networks and fabrics for medical use

Engineered collagen-PEO nanofibers and fabrics.

Photo-cross-linking of type I collagen gels in the presence of smooth muscle cells: mechanical properties, cell viability, and function

Viscoelastic and mechanical behavior of recombinant protein elastomers.

Photomediated Solid-State Cross-Linking of an Elastin-Mimetic Recombinant Protein Polymer