Promotion of dermal tissue engineering in a rat model using a composite 3D-printed scaffold with electrospun nanofibers and recipient-site preconditioning with an external volume expansion device.

We hypothesized that use of a composite three-dimensionally (3D) printed scaffold with electrospun nanofibers in conjunction with recipient-site preconditioning with an external volume expansion (EVE) device would enable successful dermal tissue regeneration of a synthetic polymer scaffold. Cell viability, cell infiltration, extracellular matrix deposition, scaffold contraction, and mRNA expression by dermal fibroblasts cultured on three different scaffolds, namely, 3D-printed scaffold with a collagen coating, 3D-printed scaffold with an electrospun polycaprolactone nanofiber and collagen coating, and 3D-printed scaffold with an electrospun polycaprolactone/collagen nanofiber, were measured. Before scaffold implantation, rats were treated for 2 h with an EVE device to evaluate the effect of this device on the recipient site.

Micropatterning and characterization of electrospun poly(ε-caprolactone)/gelatin nanofiber tissue scaffolds by femtosecond laser ablation for tissue engineering applications.

Experimental investigations aimed at assessing the effectiveness of femtosecond (FS) laser ablation for creating microscale features on electrospun poly(ε-caprolactone) (PCL)/gelatin nanofiber tissue scaffold capable of controlling cell distribution are described. Statistical comparisons of the fiber diameter and surface porosity on laser-machined and as-spun surface were made and results showed that laser ablation did not change the fiber surface morphology. The minimum feature size that could be created on electrospun nanofiber surfaces by direct-write ablation was measured over a range of laser pulse energies.

Micronozzle array enhanced sandwich electroporation of embryonic stem cells.

Electroporation is one of the most popular nonviral gene transfer methods for embryonic stem cell transfection. Bulk electroporation techniques, however, require a high electrical field and provide a nonuniform electrical field distribution among randomly distributed cells, leading to limited transfection efficiency and cell viability, especially for a low number of cells. We present here a membrane sandwich electroporation system using a well-defined micronozzle array.

Stability and inheritance of endosperm-specific expression of two transgenes in progeny from crossing independently transformed barley plants.

To study stability and inheritance of two different transgenes in barley, we crossed a homozygous T(8) plant, having uidA (or gus) driven by the barley endosperm-specific B(1)-hordein promoter (localized in the near centromeric region of chromosome 7H) with a second homozygous T(4) plant, having sgfp(S65T) driven by the barley endosperm-specific D-hordein promoter (localized on the subtelomeric region of chromosome 2H). Both lines stably expressed the two transgenes in the generations prior to the cross. Three independently crossed F(1) progeny were analyzed by PCR for both uidA and sgfp(S65T) in each plant and functional expression of GUS and GFP in F(2) seeds followed a 3:1 Mendelian segregation ratio and transgenes were localized by FISH to the same location as in the parental plants.

A high-resolution karyotype of cucumber (Cucumis sativus L. 'Winter Long') revealed by C-banding, pachytene analysis, and RAPD-aided fluorescence in situ hybridization.

Using molecular cytogenetic DNA markers, C-banding, pachytene analysis, and fluorescence in situ hybridization (FISH), a high-resolution karyotype was established in the cucumber. C-banding showed distinct hetero chromatic bands on the pericentromeric, telomeric, and intercalary regions of the chromosomes. The C-banding patterns were also consistent with the morphology of 4'-6-diamino-2-phenylindole dihydrochloride (DAPI)-stained pachytene chromosomes.

Endosperm-specific expression of green fluorescent protein driven by the hordein promoter is stably inherited in transgenic barley (Hordeum vulgare) plants.

The expression of green fluorescent protein (GFP) and its inheritance were studied in transgenic barley (Hordeum vulgare L.) plants transformed with a synthetic green fluorescent protein gene [sgfp(S65T)] driven by either a rice actin promoter or a barley endosperm-specific d-hordein promoter. The gene encoding phosphinothricin acetyltransferase (bar), driven by the maize ubiquitin promoter and intron, was used as a selectable marker to identify transgenic tissues.