Electrospinning is a fabrication process that uses an electric field to control the deposition of polymer fibers onto a target substrate. This electrostatic processing strategy can be used to fabricate fibrous polymer mats composed of fiber diameters ranging from several microns down to 100 nm or less. In this study, we describe how electrospinning can be adapted to produce tissue-engineering scaffolds composed of collagen nanofibers. Optimizing conditions for calfskin type I collagen produced a matrix composed of 100 nm fibers that exhibited the 67 nm banding pattern that is characteristic of native collagen. The structural properties of electrospun collagen varied with the tissue of origin (type I from skin vs type I from placenta), the isotype (type I vs type III), and the concentration of the collagen solution used to spin the fibers. Electrospinning is a rapid and efficient process that can be used to selectively deposit polymers in a random fashion or along a predetermined and defined axis. Toward that end, our experiments demonstrate that it is possible to tailor subtle mechanical properties into a matrix by controlling fiber orientation. The inherent properties of the electrospinning process make it possible to fabricate complex, and seamless, three-dimensional shapes. Electrospun collagen promotes cell growth and the penetration of cells into the engineered matrix. The structural, material, and biological properties of electrospun collagen suggest that this material may represent a nearly ideal tissue engineering scaffold.

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Significant challenges must be overcome before the true benefit and economic impact of vascular tissue engineering can be fully realized. Toward that end, we have pioneered the electrospinning of micro- and nano-fibrous scaffoldings from the natural polymers collagen and elastin and applied these to development of biomimicking vascular tissue engineered constructs. The vascular wall composition and structure is highly intricate and imparts unique biomechanical properties that challenge the development of a living tissue engineered vascular replacement that can withstand the high pressure and pulsatile environment of the bloodstream. The potential of the novel scaffold presented here for the development of a viable vascular prosthetic meets these stringent requirements in that it can replicate the complex architecture of the blood vessel wall. This replication potential creates an "ideal" environment for subsequent in vitro development of a vascular replacement. The research presented herein provides preliminary data toward the development of electrospun collagen and elastin tissue engineering scaffolds for the development of a three layer vascular construct.

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As parasitoids upon solitary bees and wasps and their nest cohabitants, Melittobia have an intricate life history that involves both female cooperation and variably expressed male siblicidal conflict. Inter- and intrasexual dimorphism includes blind, flightless males and (probably nutritionally determined) short- and long-winged females. Thought to be highly inbred, Melittobia do not conform to local mate competition (LMC) theory but exhibit simple forms of many social insect traits, including overlapping adult generations, different female phenotypes, close kinship ties, parental care, and altruistic cooperative escape behaviors. Most host records and research findings are based on only 3 species--M. acasta, M. australica, and M. digitata--but any of the 12 species could have pest potential due to their polyphagy, explosive population growth, cryptic habits, and behavioral plasticity. Readily cultured in the laboratory, Melittobia offer considerable potential as a model for genetic, developmental, and behavioral studies.