Histology and symplasmic tracer distribution during development of barley androgenic embryos

The present study concerns three aspects of barley androgenesis: (1) the morphology and histology of the embryos during their development, (2) the time course of fluorescent symplasmic tracers’ distribution, and (3) the correlation between symplasmic communication and cell differentiation. The results indicate that barley embryos, which are developing via an androgenic pathway, resemble their zygotic counterparts with respect to their developmental stages, morphology and histology. Analysis of the distribution of the symplasmic tracers, HPTS, and uncaged fluorescein indicates the symplasmic isolation of (1) the protodermis from the underlying cells of the late globular stage onwards, and (2) the embryonic organs at the mature stage of development

Antibacterial composite hydrogels of graphene quantum dots and bacterial cellulose accelerate wound healing

The increased antibiotic resistance of pathogenic bacteria requires intense research of new wound healing agents. Novel wound dressings should be designed to provide wound disinfection, good moisture, and fast epithelization. In this study, bacterial cellulose (BC) was impregnated with graphene quantum dots (GQDs) for potential use in wound healing treatment. The BC was successfully loaded with approximately 11.7 wt% of GQDs. The actual release of GQDs from new designed composite hydrogels were 13%. Novel GQDs-BC hydrogel composites are biocompatible and showed significant inhibition towards Staphylococcus aureus and Streptococcus agalactiae and bactericidal effect towards Methicillin-resistant Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The in vitro healing analysis showed significant migration of human fibroblasts after the GQDs-BC hydrogels application. Furthermore, after 72 h exposure to GQDs-BC, endothelial nitric oxide synthase, vascular endothelial growth factor A, matrix metallopeptidase 9, and Vimentin gene expression in fibroblast were significantly upregulated promoting angiogenesis. GQDs-BC hydrogel composites showed very good wound fluid absorption and water retention, which satisfies good dressing properties. All obtained results propose new designed GQDs-BC hydrogels as potential wound dressings

Photoactive graphene quantum dots/bacterial cellulosehydrogels: Structural, mechanical, and pro-oxidant study

Due to their unique structural properties bacterial cellulose (BC) hydrogels find possible usage in many fields such as cosmetology, food industry, or medicine. In this study, photoactive BC hydrogels are investigated through modifications of their structural, mechanical, and pro-oxidant properties resulting from graphene quantum dots (GQDs) encapsulation. Detailed structural analysis is conducted by atomic force microscopy, transmission electron microscopy and scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction method. Dynamic mechanical analysis is performed to study the changes in storage modulus, loss modulus and tan δ. Pro-oxidative properties of new designed composites are tested by electron paramagnetic resonance (EPR). Structural and mechanical analyses show successful encapsulation of GQDs into BC whereas EPR measurements indicate high potential of these composites for singlet oxygen production

Photoactive and antioxidant nanochitosan dots/biocellulose hydrogels for wound healing treatment

Bacterial infection and their resistance to known antibiotics delays wound healing. In this study, nanochitosan dots (nChiD) produced by gamma irradiation have been encapsulated in bacterial cellulose (BC) polymer matrix to study the antibacterial potentials of these nanocomposites and their possible usage in wound healing treatment (scratch assay). Detailed analyses show that nChiDs have disc-like shape and average diameter in the range of 40 to 60 nm depending of the applied dose. All nChiDs as well as BC-nChiD nanocomposites emit green photoluminescence independently on the excitation wavelengths. The new designed nanocomposites do not have a cytotoxic effect; antioxidant analysis shows their moderate radical scavenging activity whereas antibacterial properties show significant growth inhibition of strains mostly found in difficult-to-heal wounds. The obtained results confirm that new designed BC-nChiD nanocomposites might be potential agent in wound healing treatment.Supplementary material: [http://aspace.agrif.bg.ac.rs/handle/123456789/5993