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.