Colloidal synthesis of biocompatible iron disulphide nanocrystals.

The aim of this research was to synthesis biocompatible iron disulphide nanocrystals at different reaction temperatures using the colloidal synthesis methodology. Synthesis was conducted at the 220-240 °C range of reaction temperatures at intervals of 5 °C in an inert argon atmosphere. The toxicity of iron disulphide nanocrystals was evaluated in vitro using mouse fibroblast cell line. Two complementary assays were conducted: the first to evaluate cell viability of the fibroblast via an MTT assay and the second to determine the preservation of fibroblast nuclei integrity through DAPI staining, which labels nuclear DNA in fluorescence microscopes. Through TEM and HRTEM, we observed a cubic morphology of pyrite iron disulphide nanocrystals ranging in sizes 25-50 nm (225 °C), 50-70 nm (230 °C) and >70 nm (235 °C). Through X-ray diffraction, we observed a mixture of pyrite and pyrrohotite in the samples synthesized at 225 °C and 240 °C, showing the best photocatalytic activity at 80% and 65%, respectively, for the degradation of methylene blue after 120 minutes. In all experimental groups, iron disulphide nanocrystals were biocompatible, i.e. no statistically significant differences were observed between experimental groups as shown in a one-way ANOVA and Tukey's test. Based on all of these results, we recommend non-cytotoxic semiconductor iron sulphide nanocrystals for biomedical applications.

Nanomaterials made of non-toxic metallic sulfides: A systematic review of their potential biomedical applications.

Metallic sulfides involve the chemical bonding of one or more sulfur atoms to a metal. Metallic sulfides are cheap, abundant semiconductor materials that can be used for several applications. However, an important and emerging use for non-toxic metallic sulfides in biomedical applications has arisen quickly in the medical field. In this systematic review, the available data from electronic databases were collected according to PRISMA alignments for systematic reviews. This review shows that these metallic sulfides could be promising for biomedical uses and applications. This systematic review is focused primarily on the following compounds: silver sulfide, copper sulfide, and iron sulfide. The aim of this review was to provide a quick reference on synthesis methods, biocompatibility, recent advances and perspectives, with remarks on future improvements. The toxicity of metallic sulfides depends directly on the cytotoxicity of their interactions with cells and tissues. Metallic sulfides have potential biomedical applications due to their antibacterial properties, uses in imaging and diagnostics, therapies such as photothermal therapy and chemotherapy in tumors and cancer cells, drug delivery and the fabrication of biosensors for the sensitive and selective detection of moieties, among others. Although current evidence about metallic sulfide NPs is promising, there are still several issues to be addressed before these NPs can be used in biomedicine. The current review is a brief but significant guide to metallic sulfides and their potential uses in the biomedical field.

Role of sulfites and 4-hexylresorcinol in microbial growth and melanosis prevention of deepwater pink shrimp (Parapenaeus longirostris) using a controlled atmosphere.

A controlled atmosphere containing 48% CO2 and 7% O2 was used in association with refrigeration for storage of deepwater pink shrimp (Parapenaeus longirostris). Shrimp were treated with two different concentrations of sodium metabisulfite or 4-hexylresorcinol and subjected to the controlled atmosphere immediately after capture onboard ship or on arrival in port. Total volatile basic nitrogen, total viable counts, enterobacteria, lactic acid bacteria, and luminescent bacteria were determined, and black spot progression was evaluated. The combined effect of controlled atmosphere and melanosis inhibitors was used to delay black spot development as compared to the shrimp stored in ice alone. Storage under the controlled atmosphere without ice limited microbiological quality, namely, total viable counts, but enterobacterial growth was lower.

Injertos óseos y biomateriales en implantología oral / Bone grafts and bone substitutes in implant dentistry

Un adecuado volumen óseo es uno de los factores críticos para conseguir la oseointegración a largo plazo. En situaciones con un inadecuado volumen de hueso, especialmente la mandíbula atrófica, las técnicas de aumento del reborde alveolar son frecuentemente necesarias para un tratamiento predecible con implantes. Los injertos son fundamentales para reparar y regenerar el tejido óseo. Además, algunos biomateriales han sido evaluados para la regeneración ósea como material de relleno dependiendo de sus características y el área de aplicación. Los injertos autólogos han sido considerados como el material ideal de aumento óseo. Muchas técnicas de han desarrollado para reconstruir estos defectos alveolares. De acuerdo con la técnica, se regulariza el reborde alveolar y se utiliza el bloque de injerto solo o con hueso particulado o biomateriales, estabilizados con tornillos de osteosíntesis. Conclusiones: Este estudio indica que la rehabilitación de la mandíbula atrófica mediante técnicas quirúrgicas complejas con injertos óseos e implantes constituye un tratamiento con una elevada tasa de éxito

An adequate volume of bone is one of the factors critical to successful osseointegration and long-term retention of endosseous dental implants. In situations where inadequate bone volumes exist, specially atrophic mandible, osseous ridge augmentation procedures often are necessary for predictable implant therapy. Grafts are fundamental for regenerating and repairing of bone tissue. Moreover, several types of filling biomaterials have been evaluated for bone regeneration and the choice of the biomaterial mostly depends on its features and application site. Autogenous bone grafts are generally considered one of the more ideal augmentation materials. Many different techniques have been developed to reconstruct deficient alveolar jaws. According to bone graft technique, after the surgical exposure and the removal of any irregularity of the residual ridge, autologous bone blocks, used alone or associated with particulated bone and bone substitutes, are stabilized by means of small bone screws. Conclusiones: This study indicate that rehabilitation of atrophic mandible by advanced surgery techniques with bone grafts and dental implants constitute a treatment with a high success rate