Chitosan: Properties and Its Application in Agriculture in Context of Molecular Weight.

Chitosan is a naturally occurring compound that can be obtained from deacetylated chitin, which is obtained from various sources such as fungi, crustaceans, and insects. Commercially, chitosan is produced from crustaceans. Based on the range of its molecular weight, chitosan can be classified into three different types, namely, high molecular weight chitosan (HMWC, >700 kDa), medium molecular weight chitosan (MMWC, 150-700 kDa), and low molecular weight chitosan (LMWC, less than 150 kDa). Chitosan shows several properties that can be applied in horticultural crops, such as plant root growth enhancer, antimicrobial, antifungal, and antiviral activities. Nevertheless, these properties depend on its molecular weight (MW) and acetylation degree (DD). Therefore, this article seeks to extensively review the properties of chitosan applied in the agricultural sector, classifying them in relation to chitosan's MW, and its use as a material for sustainable agriculture.

5-Fluorouracil nano-delivery systems as a cutting-edge for cancer therapy.

5-Fluorouracil (5-FU) is amongst the most commonly used antimetabolite chemotherapeutic agents in recent decades. However, its low bioavailability, short half-life, rapid metabolism and the development of drug resistance after chemotherapy limit its therapeutic efficiency. In this study, 5-FU applications as an anti-cancer drug for treating diverse types of cancers (e.g. colon, pancreatic and breast) have been reviewed. Different approaches lately designed to circumvent the drawbacks of 5-FU therapy are described herein, including 5-FU-loaded lipid-based nanoparticles (NPs), polymeric NPs (both stimuli and non-stimuli responsive), carbon-based nanostructures and inorganic NPs. Furthermore, co-delivery systems of 5-FU with other drugs (e.g. paclitaxel, gelatin-doxorubicin and naproxen) have been reviewed, which aid to attain better bioavailability, higher effectiveness at a lower concentration and lower toxicity. This review provides researchers with the latest progress on 5-FU-loaded nanocarriers, which show great potential as an advanced tool for cancer therapy.

Effect of Silk Fibroin on Cell Viability in Electrospun Scaffolds of Polyethylene Oxide.

In this study, a coating from electrospun silk fibroin was performed with the aim to modify the surface of breast implants. We evaluated the effect of fibroin on polymeric matrices of poly (ethylene oxide) (PEO) to enhance cell viability, adhesion, and proliferation of HaCaT human keratinocytes to enhance the healing process on breast prosthesis implantation. We electrospun six blends of fibroin and PEO at different concentrations. These scaffolds were characterized by scanning electron microscopy, contact angle measurements, ATR-FTIR spectroscopy, and X-ray diffraction. We obtained diverse network conformations at different combinations to examine the regulation of cell adhesion and proliferation by modifying the microstructure of the matrix to be applied as a potential scaffold for coating breast implants. The key contribution of this work is the solution it provides to enhance the healing process on prosthesis implantation considering that the use of these PEO⁻fibroin scaffolds reduced (p < 0.05) the amount of pyknotic nuclei. Therefore, viability of HaCaT human keratinocytes on PEO⁻fibroin matrices was significantly improved (p < 0.001). These findings provide a rational strategy to coat breast implants improving biocompatibility.

Physico-chemical characteristics of coated silicone textured versus smooth breast implants differentially influence breast-derived fibroblast morphology and behaviour.

Capsule formation is an inevitable consequence of silicone breast implantation. Clinically challenging dense fibrocollagenous capsular contractures occur at different rates between smooth compared to textured surfaces. Host response is influenced by several factors including implant surface texture, chemistry and interactions between cells and the extracellular matrix (ECM). Specific coatings can modify the physico-chemical properties of implant surfaces eliciting specific cellular reactions. Therefore, we evaluated the physico-chemical characteristics of coated smooth versus textured silicone breast implants on breast-derived fibroblast morphology and behaviour using (a) confocal laser microscopy, (b) Raman spectroscopy and (c) the effect of four unique protein and glycosaminoglycan (GAG) coatings (aggrecan, collagen I, fibronectin and hyaluronic acid) on breast-derived fibroblast attachment, proliferation, morphology, spreading, cytotoxicity and gene expression. Collagen I, fibronectin and hyaluronic acid coatings exhibited satisfactory fibroblast adhesion (p<0.001) in comparison to uncoated surfaces. Cell adhesion was less on smooth surfaces compared to textured surfaces (p<0.001). Fibroblasts cultured on collagen I, fibronectin and hyaluronic acid coated implants demonstrated improved cell proliferation than uncoated surfaces (p<0.001). LDH assay showed that coating surfaces with collagen I, fibronectin and hyaluronic acid did not induce cytotoxicity. Alpha-actinin expression and fibroblast adhesion to the substrate were upregulated (p<0.001), in textured versus smooth surfaces. FAK, vinculin and paxillin expression were upregulated (p<0.001), in all surfaces coated with fibronectin and collagen I. In conclusion, we present original data for expression of adhesion-related genes, cell morphology and proliferation in breast fibroblasts following the application of specific coatings on breast implant surfaces.

Characterisation of breast implant surfaces and correlation with fibroblast adhesion.

INTRODUCTION: Capsular contracture formation is a common complication following breast augmentation surgery. Breast implant shells have either a smooth or a textured surface. Smooth surfaces demonstrate a higher incidence of contracture formation. The 3-dimensional surface of textured implants is thought to disrupt contractile forces and reduce capsular contracture rates. AIM: To investigate the interaction of fibroblasts with silicone breast implant surfaces through characterization of their unique features. METHOD: Surfaces of smooth and textured breast implants were characterized using a confocal laser scanning microscope, a microtest 5 kN tensile testing device, and a contact angle goniometer. The kinetics of fibroblast interaction with these surfaces was further analysed. RESULTS: The textured surfaces were rough, and nodular containing high peaks and deep crevasses with roughness (Sa) values in the range 8.88-18.83 µm and contact angles between 130° and 142°. The smooth implant surfaces were less rough, more regular and repetitive with 0.06-0.07 µm surface roughness, and contact angles between 110.9° and 111.8°. The textured surfaces displayed higher bending stiffness than the smooth surfaces (0.19 and 0.26 N mm). Significant (p<0.05) numbers of fibroblasts were attached to the textured surfaces compared to the smooth surfaces which had higher levels of cell adhesion with surface roughness above 8 µm and contact angles above 130°. CONCLUSIONS: In summary, surfaces with arithmetical mean deviation of greater roughness and reduced hydrophilicity with high water contact angles enhanced cell adhesion. These features aid design of improved surfaces, which may help, in prevention of breast capsular formation.