The latest achievements in plant cellulose-based biomaterials for tissue engineering focusing on skin repair.

The present work reviews recent developments in plant cellulose-based biomaterial design and applications, properties, characterizations, and synthesis for skin tissue engineering and wound healing. Cellulose-based biomaterials are promising materials for their remarkable adaptability with three-dimensional polymeric structure. They are capable of mimicking tissue properties, which plays a key role in tissue engineering. Besides, concerns for environmental issues have motivated scientists to move toward eco-friendly materials and natural polymer-based materials for applications in the tissue engineering field these days. Therefore, cellulose as an appropriate substitute for common polymers based on crude coal, animal, and human-derived biomolecules is greatly considered for various applications in biomedical fields. Generally, natural biomaterials lack good mechanical properties for skin tissue engineering. But using modified cellulose-based biopolymers tackles these restrictions and prevents immunogenic responses. Moreover, tissue engineering is a quick promoting field focusing on the generation of novel biomaterials with modified characteristics to improve scaffold function through physical, biochemical, and chemical tailoring. Also, nanocellulose with a broad range of applications, particularly in tissue engineering, advanced wound dressing, and as a material for coupling with drugs and sensorics, has been reviewed here. Moreover, the potential cytotoxicity and immunogenicity of cellulose-based biomaterials are addressed in this review.

Development of a cellulose-based scaffold for sustained delivery of curcumin.

Due to the unique properties of cellulose-based materials, they are attractive to be developed in industrial pharmaceutics and biomedical fields. Carboxymethyl-diethyl amino ethyl cellulose scaffold (CM-DEAEC) has been synthesized in the current work as a smart novel derivative of cellulose with a great functionality in drug delivery systems. The scaffolds were well cross-linked with 2% (v/v) epichlorohydrin (ECH), loaded with curcumin (Cur), and then were analyzed by FT-IR, XRD, SEM, and mechanical strength. While developing the ideal delivery platform, curcumin (an important chemotherapeutic agent) was chosen due to its hydrophobicity and poor bioavailability. Thus, we developed a novel scaffold for efficient loading and controlled releasing of curcumin. The swelling ratio of 136%, high curcumin entrapment efficiency (up to 83.7%), sustained in vitro drug release profile, and appropriate degradability in three weeks confirmed significant properties of the CM-DEAEC scaffold. More than 99% antibacterial activity has been observed by the cross-linked curcumin loaded CM-DEAEC scaffolds. Cytotoxicity studies using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and 4',6-diamidino-2-phenylindole (DAPI) staining showed that cross-inked curcumin loaded CM-DEAEC scaffolds did not show any toxicity using L929 cells. All experiments were compared with CMC scaffolds and better characteristics of the novel scaffold for drug delivery have been confirmed.

A review on in vivo and in vitro nanotoxicological studies in plants: A headlight for future targets.

Owing to the unique properties and useful applications in numerous fields, nanomaterials (NMs) received a great attention. The mass production of NMs has raised major concern for the environment. Recently, some altered growth patterns in plants have been reported due to the plant-NMs interactions. However, for NMs safe applications in agriculture and medicine, a comprehensive understanding of bio-nano interactions is crucial. The main goal of this review article is to summarize the results of the toxicological studies that have shown the in vitro and in vivo interactions of NMs with plants. The toxicity mechanisms are briefly discussed in plants as the defense mechanism works to overcome the stress caused by NMs implications. Indeed, the impact of NMs on plants varies significantly with many factors including physicochemical properties of NMs, culture media, and plant species. To investigate the impacts, dose metrics is an important analysis for assaying toxicity and is discussed in the present article to broadly open up different aspects of nanotoxicological investigations. To access reliable quantification and measurement in laboratories, standardized methodologies are crucial for precise dose delivery of NMs to plants during exposure. Altogether, the information is significant to researchers to describe restrictions and future perspectives.

Polyhydroxyalkanoates (PHA): From production to nanoarchitecture.

Among many biodegradable and biocompatible biopolymers, polyhydroxyalkanoates (PHAs), generated by microorganisms, have highly attracted attention in various fields due to their unique physicochemical properties. So far, various types of progresses have been made in environmental and engineering fields by employing PHAs. Recently, employing PHAs for nanoarchitecture has become a newly emerging trend among researchers. The intrinsic nature of PHAs has dragged them towards fabrication of nanoparticles and nanocomposites. PHAs integration with nanoparticles has been vastly noted and applied in various areas such as drug delivery, antibacterial agents and bioengineering. Here, a brief review is given to how PHAs act and are produced by microorganisms, demonstrating their properties and finally, their most recent applications are discussed in nanoarchitecture and the ways they are manipulated in the fabrication of nanomaterials. This review can shed light on the exhaustive understanding of PHA capability in nanoarchitectural basics toward the development of advanced nanomaterials in many fields such as medicine, catalysis, sensor, and adsorbents.

Toxicity of cadmium selenide nanoparticles on the green microalgaChlorella vulgaris: inducing antioxidative defense response.

Green algae are dominant primary producers in aquatic environments. Thus, assessing the influences of pollutants such as nanoparticles on the algae is of high ecological significance. In the current study, cadmium selenide nanoparticles (CdSe NPs) were synthesized using the hydrothermal method and their characteristics were determined by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FT-IR) techniques. Subsequently, the toxicity of synthesized nanoparticles on the green microalga Chlorella vulgaris was investigated. The observations by SEM confirmed that exposure to CdSe NPs had severe impacts on the algal morphology. Furthermore, the obtained results revealed the toxic effect of CdSe NPs by a decrease in the number of cells. Measurement of antioxidant enzymes activity showed an increase in the activity of catalase, and a decrease in the activity of superoxide dismutase (SOD) at high concentrations of CdSe NPs. The exposure of C. vulgaris to CdSe NPs resulted also in a change in algal pigments as well as total phenol content. Taken together, CdSe NPs appeared to have significant cytotoxic effects on C. vulgaris in the applied concentrations.

Evaluating the Toxic Impacts of Cadmium Selenide Nanoparticles on the Aquatic Plant Lemna minor.

Cadmium selenide nanoparticles (CdSe NPs) were synthesized by an easy and simple method and their properties were assessed by XRD, TEM and SEM techniques. The effects of CdSe NPs as well as Cd2+ ions on Lemna minor plants were investigated. The absorption of CdSe NPs by the plants had some adverse consequences that were assessed by a range of biological analyses. The results revealed that both CdSe NPs and the ionic form of cadmium noticeably caused toxicity in L. minor. Morphological parameters as well as peroxidase (POD) activity were deteriorated. In contrast, the activities of some other antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) as well as the contents of total phenol and flavonoids went up. Taken all together, it could be implied that CdSe NPs as well as Cd2+ were highly toxic to plants and stimulated the plant defense system in order to scavenge produced reactive oxygen species (ROS).

Toxicity of ZnSe nanoparticles to Lemna minor: Evaluation of biological responses.

A clear consequence of the increasing application of nanotechnology is its adverse effect on the environment. Semiconductor nanoparticles are among engineered nanomaterials that have been considered recently for their specific characteristics. In the present work, zinc selenide nanoparticles (ZnSe NPs) were synthesized and characterized by XRD, TEM, DLS and SEM. Biological aspects related to the impact of nanoparticles and Zn2+ ions were analyzed on the aquatic higher plant Lemna minor. The localization of ZnSe NPs in the root cells of L. minor was determined by TEM and fluorescence microscopy. Then, the entrance of ZnSe NPs into the plant cells was evaluated by a range of biological tests. The outcomes revealed that both the NPs and the ionic forms noticeably poisoned L. minor. In one hand, growth parameters and physiological indices such as photosynthetic pigments content were decreased. On the other hand, the activities of some antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)), as well as the contents of nonenzymatic antioxidants (phenols and flavonoids) were elevated. Taken together, high concentration of ZnSe NPs and Zn2+ triggered phytotoxicity which in turn provoked the plants' defense system. The changes in antioxidant activities confirmed a higher toxicity by Zn2+ ions in comparison with ZnSe NPs. It means that the considered ions are more hazardous to the living organisms than the nanoparticles.

Effects of TiO2 nanoparticles on the aquatic plant Spirodela polyrrhiza: Evaluation of growth parameters, pigment contents and antioxidant enzyme activities.

Plants are essential components of all ecosystems and play a critical role in environmental fate of nanoparticles. However, the toxicological impacts of nanoparticles on plants are not well documented. Titanium dioxide nanoparticles (TiO2-NPs) are produced worldwide in large quantities for a wide range of purposes. In the present study, the uptake of TiO2-NPs by the aquatic plant Spirodela polyrrhiza and the consequent effects on the plant were evaluated. Initially, structural and morphological characteristics of the used TiO2-NPs were determined using XRD, SEM, TEM and BET techniques. As a result, an anatase structure with the average crystalline size of 8nm was confirmed for the synthesized TiO2-NPs. Subsequently, entrance of TiO2-NPS to plant roots was verified by fluorescence microscopic images. Activity of a number of antioxidant enzymes, as well as, changes in growth parameters and photosynthetic pigment contents as physiological indices were assessed to investigate the effects of TiO2-NPs on S. polyrrhiza. The increasing concentration of TiO2-NPs led to the significant decrease in all of the growth parameters and changes in antioxidant enzyme activities. The activity of superoxide dismutase enhanced significantly by the increasing concentration of TiO2-NPs. Enhancement of superoxide dismutase activity could be explained as promoting antioxidant system to scavenging the reactive oxygen species. In contrast, the activity of peroxidase was notably decreased in the treated plants. Reduced peroxidase activity could be attributed to either direct effect of these particles on the molecular structure of the enzyme or plant defense system damage due to reactive oxygen species.

Toxicological implications of selenium nanoparticles with different coatings along with Se4+ on Lemna minor.

Nanoparticles have potential high risks for living organisms in the environment due to their specific qualities and their easy access. In the present study, selenium nanoparticles (Se NPs) with two different coatings (l-cysteine and tannic acid) were synthesized. The characteristics of particles were analyzed using XRD, FT-IR and SEM. The impact of the nanoparticles besides Se4+, on the aquatic higher plant Lemna minor was evaluated and compared. Entrance of l-cysteine and tannic acid capped Se NPs in the roots of Lemna minor was proved by TEM and fluorescence microscopy. Adverse effects of mentioned NPs and differences of these effects from those by sodium selenite as the ionic form were assessed by a range of biophysicochemical tests. Altogether, the results asserted that Lemna minor was notably poisoned by both capped Se NPs and Se4+. Thus, growth and photosynthetic pigments were decreased while lipid peroxidation along with total phenol and flavonoid contents were raised. Eventually some changes in enzymatic activities were presented. To sum up the consequences, it can be concluded that all changes occurred due to the plant defense system especially in order to remove reactive oxygen species (ROS) and possible phytotoxicity originated by l- cysteine and tannic acid capped Se NPs in addition to Se4+. The influence of tannic acid capped Se NPs after sodium selenite is stronger by the means of antioxidant enzymes activity in comparison with l-cysteine capped Se NPs.