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In recent years, antibacterial wound dressings have gained considerable attention. Bacterial cellulose (BC) has received significant interest due to its unique physiochemical characteristics such as biocompatibility, high porosity, superior mechanical properties, water holding capacity, and nontoxicity. In this work, silver nanoparticles/graphitic carbon nitride/eucalyptus extract (Ag/gCN/EE) nanocomposite was synthesized as an antibacterial agent and incorporated into nanofibrous structures composed of BC. The BC/Ag/gCN/EE and polyvinyl alcohol/BC/Ag/gCN/EE (PVA/BC/Ag/gCN/EE) nanocomposites were synthesized using immersion and electrospinning methods, respectively. Then, the swelling ratio was optimized and the wound dressings were prepared based on the optimal formulation. The release profile, biodegradability and mechanical properties of the wound dressings were assessed. The antibacterial property of Ag/gCN/EE was studied demonstrating strong antibacterial activity on E. coli and S. aureus. MTT assay was carried out on NIH 3T3 fibroblast cells, and BC/Ag/gCN/EE and PVA/BC/Ag/gCN/EE nanocomposites showed 89 ± 2.31 % and 96 ± 3.28 % viability, respectively and no toxicity. To assess the effect of the composites on in vitro wound healing and cell migration, scratch wound assay was performed. The results indicated that after 24 h, BC/Ag/gCN/EE and PVA/BC/Ag/gCN/EE reduced 18.69 and 23.97 % of the scratch area compared to the control group. The prepared composites are promising wound dressings that could accelerate wound healing and kill bacteria simultaneously.

5-Fluorouracil (5FU) is a common chemotherapy drug for various cancers. It has exhibited large potentials for the treatment of both malignant and premalignant tumors. In the meantime, topical application of 5FU has been limited to surface pre-carcinogenic tumors. So far, a number of nano systems have been developed for encapsulation and targeted delivery of 5FU to improve its solubility, bioavailability, and functional characteristics, leading to the development of, for example, 5FU carriers in topical treatments. Due to their considerable advantages over ordinary therapies, nanotechnology-based drug delivery systems (DDSs), particularly polymeric nanocarriers (PNCs), have led to some sorts of evolution in many fields, including disease diagnosis and DDS. As a naturally occurring polymer, chitosan (CS) has long been regarded because of its biodegradability, biocompatibility, polycationic nature, non-toxicity, and non-allergenic nature. In addition, the pH-responsive nature of CS provides an exact drug dispersion in the cancer environment, converting it a promising carrier system. Utilization of 5-FU into carbon nanocarriers has indicated positive results such as targeted delivery to tumors and prevention of cancer activity. Researchers have successfully synthesized a handful of CS nanocarriers with distinctive characteristics for targeted delivery of 5FU; these come in different forms, including nano-sized particles (NPs), composites (NCs), emulsions (NEs), and fibers (NFs). This study reviews the mechanism of CS in different formulations by analyzing the physicochemical characteristics of the corresponding DDS in terms of morphology, surface charge, release profile, and encapsulation driving force. A more detailed analysis was performed on the most popular pharmaceutical applications of 5FU-loaded CS NPs. Effective facilitation of targeted delivery of 5FU and improvement of its therapeutic effects for various cancers by the CS were also indicated. Herein, the readers are introduced to nanoscale systems based on natural polymers like chitosan as promising platforms for cancer diagnosis and therapy. More recent discoveries on mechanistic anticancer behavior of 5FU-loaded CS NPs was further discussed.

3D bioprinting techniques have emerged as a flexible tool in tissue engineering and regenerative medicine to fabricate or pattern functional 3D bio-structures with precise geometric designs, bridging the divergence between engineered and natural tissue constructs. A significantly increasing development has been achieved in understanding the relationship between the 3D-printing process and the structures, properties, and applications of the objects created. The ongoing advancement of novel biomaterial inks has enabled manufacturing of models and in vitro implants capable of achieving some level of success in preclinical trials. Remarkable progress in cell biology and biology-inspired computational design has assisted in achieving the latest milestone with planned tissue- or organ-like constructs having specific levels of functionality. However, biofabricated constructs still have a long way to go before reaching clinics. This review presents a picture of 3D bioprinting in the context of tissue engineering and regenerative medicine, with focus on biomaterials-related and design-centred aspects. Biomedical applications are described in detail in relation to major tissues or organs considered in the human body. Current technical limitations, challenges, future prospects and improvements are critically outlined and discussed.

The partial replacement of cement or natural aggregates with industrial wastes and using microbially-induced carbonate precipitation to heal cracks are two developing methods to make more sustainable concrete. In this study, a combination of these two methods was used for the first time: Partial replacement of cement with silica fume to economically create a more favorable pH for bacterial activity and substituting natural sands partially with scoria aggregates as a novel carrier and protector for bacterial spores against the harsh and alkaline conditions of cement mortar. Preliminary investigations identified scoria as a suitable carrier since the activity of immobilized cells did not decrease considerably. Thermogravimetric and X-ray diffraction analyses confirmed that spores immobilized in scoria are capable of precipitating calcium carbonate. Different mortar mixtures were made with and without scoria immobilized healing agents and silica fume. In the absence of silica fume, adding biological healing agents to mortar mixture enhanced flexural and compressive strengths by 13% and 10%, respectively, and by 18% and 15% in the silica fume amended mortars. Healing agents lowered sorptivity coefficients by 49% when samples lacked silica fume and 63% when specimens included it. The presence of silica fume resulted in a more favorable pH environment for bacterial activity and increased precipitation of calcium carbonate, as confirmed by the scanning electron microscope. Replacing a part of cement with silica fume -as an industrial byproduct- has multiple ecological benefits: protecting the environment via waste reuse, reducing demand for energy and natural resources, decreasing greenhouse gas emissions, lowering cement manufacturing costs, and finally improving the performance of microbial carbonate precipitation leads to the production of more sustainable concrete.

Background: Bioremoval of phenolic compounds using fungi and bacteria has been studied extensively; nevertheless, trinitrophenol bioremediation using modified Oscillatoria cyanobacteria has been barely studied in the literature. Results: Among the effective parameters of bioremediation, algal concentration (3.18 g·L−1), trinitrophenol concentration (1301 mg·L−1), and reaction time (3.75 d) were screened by statistical analysis. Oscillatoria cyanobacteria were modified by starch/nZVI and starch/graphene oxide in a bubble column bioreactor, and their bioremoval efficiency was investigated. Modifiers, namely, starch/zero-valent iron and starch/GO, increased trinitrophenol bioremoval efficiency by more than 10% and 12%, respectively, as compared to the use of Oscillatoria cyanobacteria alone. Conclusions: It was found that starch/nano zero-valent iron and starch/GO could be applied to improve the removal rate of phenolic compounds from the aqueous solution.How to cite: Bavandi R, Emtyazjoo M, Saravi HN, et al. Study of nano-structure zero-valent iron and graphene-oxid capability onbioremoval of trinitrophenol from wastewater in a bubble column bioreactor. Electron J Biotechnol 2019;39. https://doi.org/10.1016/j.ejbt.2019.02.003. Keywords: High bioremoval, Trinitrophenol, Oscillatoria cyanobacteria, Starch/nano zero-valent iron, Starch/GO/Oscillatoria, Phenolic compounds, Bioremediation, Cyanobacteria, Bioreactor, Bubble column

Chitosan is a natural mucoadhesive, biodegradable, biocompatible and nontoxic polymer which has been used in pharmaceutical industry for a lot of purposes such as dissolution enhancing, absorption enhancing, sustained releasing and protein, gene or drug delivery. Two major disadvantages of chitosan are poor solubility in physiological pH and low efficiency for protein and gene delivery. In this study thiolated methylated N-(4-N,N-dimethylaminobenzyl) chitosan was prepared for the first time in order to improve the solubility and delivery properties of chitosan. This novel chitosan derivative was characterized using 1 H NMR, Ellman test, TGA and Zetasizer. Cell toxicity studies were performed on Human Embryonic Kidney 293 (Hek293) cell line using XTT method, to investigate the potential effect of this new derivative on cell viability. 1 H NMR results showed that all substitution reactions were successfully carried out. Zeta potential of new derivative at acidic and physiological pHs was greater than chitosan and it revealed an increase in solubility of the derivative. Furthermore, it had no significant cytotoxicity against Hek293 cell line in comparison to chitosan. These findings confirm that this new derivative can be introduced as a suitable compound for biomedical purposes., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Chitosan is a biocompatible, non-toxic and biodegradable biopolymer. Due to the presence of functional groups on its surface, it can be modified and used as a carrier in targeted drug/gene delivery systems. In this study, raloxifene (a selective estrogen receptor ligand) was conjugated to chitosan using different methods. The conjugates were investigated by means of FTIR, TGA and physical properties assessments. Cell viability was evaluated by XTT assay. FTIR and TGA results confirmed that the conjugation between chitosan and raloxifene occurred more efficiently when trimethyl chitosan in the presence of triethylamine and excess amount of linker was used. XTT assay on MCF-7 cell line illustrated that more than 80% of cells were viable after 24h exposure to selected molecules. These findings confirm that the conjugation of raloxifene-chitosan can occur successfully using special synthesis condition and this novel chitosan derivative can be introduced as a potential drug/gene targeting agent., (Copyright © 2015 Elsevier B.V. All rights reserved.)