Biopolymeric Nanoparticle Synthesis in Ionic Liquids

Recently, much research has focused on the use of biopolymers, which are regarded as biodegradable, natural, and environmentally friendly materials. In this context, biopolymeric nanoparticles have attracted great attention in the last few years due to their multiple applications especially in the field of biomedicine. Ionic liquids have emerged as promising solvents for use in a wide variety of chemical and biochemical processes for their extraordinary properties, which include negligible vapor pressure, high thermal and chemical stability, lower toxicity than conventional organic solvents, and the possibility of tuning their physical–chemical properties by choosing the appropriate cation and anion. We here review the published works concerning the synthesis of biopolymeric nanoparticles using ionic liquids, such as trimethylsilyl cellulose or silk fibroin. We also mention our recent studies describing how high-power ultrasounds are capable of enhancing the dissolution process of silk proteins in ionic liquids and how silk fibroin nanoparticles can be directly obtained from the silk fibroin/ionic liquid solution by rapid desolvation in polar organic solvents. As an example, their potential biomedical application of curcumin-loaded silk fibroin nanoparticles for cancer therapy is also discussed

Unexpected high toughness of Samia cynthia ricini silk gut

Silk gut fibers were produced from the silkworm Samia cynthia ricini silk glands by the usual procedure of immersion in a mildly acidic solution and subsequent stretching. The morphology of the silk guts was assessed by scanning electron microscopy, and their microstructure was assessed by infrared spectroscopy and X-ray diffraction. It was found that both naturally spun and Samia silk guts share a common semicrystalline microstructure. The mechanical characterization of the silk guts revealed that these fibers show an elastomeric behavior when tested in water, and exhibit a genuine ground state to which the fiber may revert independently of its previous loading history. In spite of its large cross-sectional area compared with naturally spun silk fibers, Samia silk guts show values of work to fracture up to 160 MJ m, much larger than those of most of their natural counterparts, and establish a new record value for this parameter in silk guts

Mechanical behaviour and formation process of silkworm silk gut

High performance silk fibers were produced directly from the silk glands of silkworms ("Bombyx mori") following an alternative route to natural spinning. This route is based on a traditional procedure that consists of soaking the silk glands in a vinegar solution and stretching them by hand leading to the so called silkworm guts. Here we present, to the authors’ best knowledge, the first comprehensive study on the formation, properties and microstructure of silkworm gut fibers. Comparison of the tensile properties and microstructural organization of the silkworm guts with those of naturally spun fibers allows gain of a deeper insight into the mechanisms that lead to the formation of the fiber, as well as the relationship between the microstructure and properties of these materials. In this regard, it is proved that an acidic environment and subsequent application of tensile stress in the range of 1000 kPa are sufficient conditions for the formation of a silk fiber

Products of Sericulture and Their Hypoglycemic Action Evaluated by Using the Silkworm, Bombyx mori (Lepidoptera: Bombycidae), as a Model

Sericulture generates different natural products with potential medical applications. Silk peptides, worms, or even pupae are commonly employed in traditional Asian medicine with a wide variety of purposes, and some scientific work has been focused on their antidiabetic properties. This work evaluates the postprandial antihyperglycemic activity of fibroin, sericin, and powder made from either larvae or pupae of silkworms, and Bombyx mori L. (Lepidoptera: Bombycidae), employing the silkworm itself as an animal model. The results indicate a reduction in the glucose levels in hemolymph after sucrose or glucose-induced hyperglycemia when these products are included in the diet of the worms

Silkworm Gut Fibres from Silk Glands of <i>Samia cynthia ricini</i>—Potential Use as a Scaffold in Tissue Engineering

High-performance fibroin fibres are ideal candidates for the manufacture of scaffolds with applications in tissue engineering due to the excellent mechanical properties and optimal biocompatibility of this protein. In this work, the manufacture of high-strength fibres made from the silk glands of Samia cynthia ricini is explored. The glands were subjected to soaking in aqueous dissolutions of acetic acid and stretched to manufacture the fibres. The materials produced were widely characterized, in terms of morphology, mechanical properties, crystallinity and content of secondary structures, comparing them with those produced by the standard procedure published for Bombyx mori. In addition, mechanical properties and biocompatibility of a braided scaffold produced from these fibres was evaluated. The results obtained show that the fibres from B. mori present a higher degree of crystallinity than those from S. c. ricini, which is reflected in higher values of elastic modulus and lower values of strain at break. Moreover, a decrease in the elongation values of the fibres from S. c. ricini was observed as the concentration of acetic acid was increased during the manufacture. On the other hand, the study of the braided scaffolds showed higher values of tensile strength and strain at break in the case of S. c. ricini materials and similar values of elastic modulus, compared to those of B. mori, displaying both scaffolds optimal biocompatibility using a fibroblast cell line

Genetic variability among local apricots (Prunus armeniaca L.) from the Southeast of Spain

La rápida rotación de nuevas variedades que exige la fruticultura moderna, implica la pérdida de muchas variedades antiguas con caracteres potencialmente valiosos. En consecuencia, surge la necesidad de mantener y caracterizar este germoplasma para futuros proyectos de mejora. La región de Murcia, junto con la de Valencia, en el este y sureste de España respectivamente, son importantes y antiguas productoras de albaricoque (Prunus armeniaca L.), y muchos cultivares autóctonos han aparecido y se han diversificado en la zona. En el Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA, Murcia, España) se mantiene una colección de 28 de estas antiguas variedades más 8 selecciones clonales del cv. �Búlida�. Para caracterizar molecularmente la diversidad e identidad genética de esta colección, se emplearon 17 marcadores microsatélite. En 13 de ellos se detectaron pautas de amplificación polimórficas y reproducibles, y se pudieron identificar 31 genotipos. Además de la evaluación de la colección, se planteó la evaluación de la diversidad genética en campo del cv. �Búlida�, que es la predominante para uso en la industria conservera de la región. Para ello se analizaron 66 muestras de campo con 7 marcadores microsatélite. Los resultados sugieren que todas las muestras de campo podrían derivar de cuatro genotipos estrechamente relacionados, agrupando uno de ellos al 89% de las muestras.The fast rotation of new cultivars demanded by modern fruit growers implies the loss of many old varieties with valuable characters. Then, the need arises to keep and characterize this germplasm for future breeding projects. The region of Murcia, together with Valencia, in the East and Southeast of Spain respectively, are important and ancient producers of apricot (Prunus armeniaca L.), and many local cultivars have appeared and diversified in this area. A collection of 28 of these old cultivars, plus eight clonal selections of the cultivar �Búlida�, is maintained at the Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA, Murcia, Spain). In order to characterize their genetic diversity and to identify the collection with molecular markers, 17 microsatellite primers pairs were used. Thirteen of these primers produced polymorphic repeatable amplification patterns, and 31 genotypes were identified among the 36 apricot accessions. In addition to this, an evaluation of the genetic diversity found in the field within the cultivar �Búlida� was made, the predominant cultivar for the canning industry in the region. For this, 66 field samples were analyzed with seven microsatellite markers. The results suggest that all the samples could derive from four closely-related genotypes, one of them accounting for 89% of the samples

Production of Curcumin-Loaded Silk Fibroin Nanoparticles for Cancer Therapy

Curcumin, extracted from the rhizome of Curcuma longa, has been widely used in medicine for centuries due to its anti-inflammatory, anti-cancer, anti-oxidant and anti-microbial effects. However, its bioavailability during treatments is poor because of its low solubility in water, slow dissolution rate and rapid intestinal metabolism. For these reasons, improving the therapeutic efficiency of curcumin using nanocarriers (e.g., biopolymer nanoparticles) has been a research focus, to foster delivery of the curcumin inside cells due to their small size and large surface area. Silk fibroin from the Bombyx mori silkworm is a biopolymer characterized by its biocompatibility, biodegradability, amphiphilic chemistry, and excellent mechanical properties in various material formats. These features make silk fibroin nanoparticles useful vehicles for delivering therapeutic drugs, such as curcumin. Curcumin-loaded silk fibroin nanoparticles were synthesized using two procedures (physical adsorption and coprecipitation) more scalable than methods previously described using ionic liquids. The results showed that nanoparticle formulations were 155 to 170 nm in diameter with a zeta potential of approximately −45 mV. The curcumin-loaded silk fibroin nanoparticles obtained by both processing methods were cytotoxic to carcinogenic cells, while not decreasing viability of healthy cells. In the case of tumor cells, curcumin-loaded silk fibroin nanoparticles presented higher efficacy in cytotoxicity against neuroblastoma cells than hepatocarcinoma cells. In conclusion, curcumin-loaded silk fibroin nanoparticles constitute a biodegradable and biocompatible delivery system with the potential to treat tumors by local, long-term sustained drug delivery

Variación genética y patogénica de Fusarium oxysporum f. sp. dianthi en España

Con el fín de profundizar en el conocimiento de la variabilidad de Fusarium oxysporum f. sp. dianthi en España, se realizó un estudio de un total de 53 aislados de este hongo, colectados en Galicia y el Sureste, junto con un grupo de ocho cepas de referencia. Se caracterizó la raza de cada aislado mediante la reacción de patogeneicidad en hospedantes diferenciales, y se determinaron sus grupos de compatibilidad vegetativa y sus pautas de amplificación mediante RAPD-PCR. De los 53 aislados, 49 fueron patogénicos, perteneciendo 46 a la raza 2, dos a la raza 4 y uno a la raza 1. Este gran predominio de la raza 2 es similar al observado en otros países. Todos los aislados de la misma raza, pertenecieron al mismo VCG y presentaron una pauta RAPD-PCR muy similar. Tres aislados no patogénicos del Sureste, presentaron cada uno un VCG y una pauta RAPD-PCR específica. La gran consistencia de los datos de VCGs y RAPD-PCR con la reacción de patogeneicidad de F. o. dianthi, pone de manifiesto el interés de estos métodos para una determinación rápida de determinadas razas de este hongo

Silk fibroin scaffolds seeded with Wharton’s jelly mesenchymal stem cells enhance re-epithelialization and reduce formation of scar tissue after cutaneous wound healing

Abstract Background The treatment of extensive and/or chronic skin wounds is a widespread and costly public health problem. Mesenchymal stem cells (MSCs) have been proposed as a potential cell therapy for inducing wound healing in different clinical settings, alone or in combination with biosynthetic scaffolds. Among them, silk fibroin (SF) seeded with MSCs has been shown to have increased efficacy in skin wound healing experimental models. Methods In this report, we investigated the wound healing effects of electrospun SF scaffolds cellularized with human Wharton’s jelly MSCs (Wj-MSCs-SF) using a murine excisional wound splinting model. Results Immunohistopathological examination after transplant confirmed the presence of infiltrated human fibroblast-like CD90-positive cells in the dermis of the Wj-MSCs-SF-treated group, yielding neoangiogenesis, decreased inflammatory infiltrate and myofibroblast proliferation, less collagen matrix production, and complete epidermal regeneration. Conclusions These findings indicate that Wj-MSCs transplanted in the wound bed on a silk fibroin scaffold contribute to the generation of a well-organized and vascularized granulation tissue, enhance reepithelization of the wound, and reduce the formation of fibrotic scar tissue, highlighting the potential therapeutic effects of Wj-MSC-based tissue engineering approaches to non-healing wound treatment