The HIV-1 envelope glycoprotein spike is the target of antibodies, and therefore represents the main viral antigen for antibody-based vaccine design. One of the challenges in HIV-1 vaccine development is finding efficient ways for the immune system to recognize and respond to HIV-1 without establishing an infection. Since HIV-1 enters the body at mucosal surfaces, induction of immune response at these sites is a preferred preventive approach.
View Article and Find Full Text PDFMarburgvirus (MARV), a member of the Filovirus family, causes severe hemorrhagic fever in humans. Currently, there are no approved vaccines or post exposure treatment methods available against MARV. With the aim of identifying vaccine candidates against MARV, we employ different sequence-based computational methods to predict the MHC-I and MHC-II T-cell epitopes as well as B-cell epitopes for the complete MARV genome.
View Article and Find Full Text PDFMany scaffold systems have evolved for tissue engineering and in vitro tissue models to provide a 3D (three-dimensional) microenvironment that enables cells to behave more physiologically. We hypothesized that cells would adopt morphologies with more 3D character during culture in scaffolds as compared to planar substrates. Cell shape and function are tightly linked and effects of scaffold niche properties on cell shape and dimensionality are important for directing cell function.
View Article and Find Full Text PDFWe have designed a 2-spinnerette device that can directly electrospin nanofiber scaffolds containing a gradient in composition that can be used to engineer interfacial tissues such as ligament and tendon. Two types of nanofibers are simultaneously electrospun in an overlapping pattern to create a nonwoven mat of nanofibers containing a composition gradient. The approach is an advance over previous methods due to its versatility - gradients can be formed from any materials that can be electrospun.
View Article and Find Full Text PDFStem cell response to a library of scaffolds with varied 3D structures was investigated. Microarray screening revealed that each type of scaffold structure induced a unique gene expression signature in primary human bone marrow stromal cells (hBMSCs). Hierarchical cluster analysis showed that treatments sorted by scaffold structure and not by polymer chemistry suggesting that scaffold structure was more influential than scaffold composition.
View Article and Find Full Text PDFBiomacromolecules
September 2008
We previously reported a system for the controlled redispersion of DNA-linked aggregates using secondary, competitive hybridization events and found that complete redispersion is contingent upon dilution of the active 20 base-long probe strands with 20 base-long nonhybridizing strands. Here, to reduce the steric interference of nonhybridizing or diluent strands on probe activity, we investigate the effect of shorter diluent strands on the hybridization activity of immobilized probes using the following two approaches: (1) simultaneously coupling shorter diluent strands and longer probe strands to microspheres and (2) simultaneously coupling diluent and probe strands of the same base length to microspheres and then clipping diluent strands with the restriction endonuclease AluI. Results indicate that one can reduce the duplex density down by 50-70% of its initial value, depending on the location of the recognition motif along the hybridization segment.
View Article and Find Full Text PDFRecognition-based assembly of micron- to nano-sized colloidal particles functionalized with DNA has generated great interest in the past decade; however, reversing the assembly process is typically achieved by thermal denaturation of the oligonucleotide duplexes. Here, we report an alternative disassembly approach at a fixed temperature using competitive hybridization events between immobilized and soluble oligonucleotide strands. Microspheres are first aggregated via primary hybridization events between immobilized DNA strands with a weak, but sufficient, affinity for partner strands to link complementary surfaces together.
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