RESUMEN
Carbon nanotubes (CNTs) are a class of carbon allotropes with interesting properties that make them productive materials for usage in various disciplines of nanotechnology such as in electronics equip-ments, optics and therapeutics. They exhibit distinguished properties viz., strength, and high electrical and heat conductivity. Their uniqueness can be attributed due to the bonding pattern present between the atoms which are very strong and also exhibit high extreme aspect ratios. CNTs are classified as single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) on the basis of number of sidewalls present and the way they are arranged spatially. Application of CNTs to improve the performance of many products, especially in healthcare, has led to an occupational and public exposure to these nanomaterials. Hence, it becomes a major concern to analyze the issues pertaining to the toxicity of CNTs and find the best suitable ways to counter those challenges. This review summarizes the toxicity issues of CNTs in vitro and in vivo in different organ systems (bio interphases) of the body that result in cellular toxicity.
RESUMEN
Objective To explore the biological safety and compatibility of five kinds of acellular fish skin matrices, and to screen the materials meeting the criteria of biocompatibility. Methods Acellular fish skin matrices were prepared through decolorization, degreasing, decellularization and cross-linking using five kinds of fish skins leather jacket fish (Thamnaconus septentrionalis), black fish (Channa argus), eel (Anguillidae), carp (Cyprinus carpio) and silver crap (Hypophthalmichthys molitrix). According to the national standard (GB/T 16886.5-2017), different concentrations (10 g/L and 100 g/L) of extracts of acellular fish skin matrices were prepared, and the CCK-8 assay was used to detect the in vitro toxicity of extracts of acellular fish skin matrices to human bone marrow-derived mesenchymal stem cells. The surface structures of different collagen membranes were observed under scanning electron microscopy. The H-E and Masson staining were used to observe whether the fish skin matrix materials were completely acellular. The human bone marrow-derived mesenchymal stem cells were cultured with the medium containing standard concentration of 100 g/L acellular fish skin matrix material extracts. The blood compatibility of the meterial was tested by hemolysis test. Live/Dead, TUNEL and flow cytometry were used to detect the cell survival and apoptosis levels. Results CCK-8 assay showed that the viability indexes of the cells co-cultured with the leather jacket fish and black fish skin acellular matrix material extracts were both 70% at the concentration of 10 g/L, and the other three materials were all 70%. At the concentration of 100 g/L, the viability index of the cells co-cultured with the leather jacket fish skin acellular matrix material extracts was 70%, and that with the black fish was 70%. Scanning electron microscopy showed that the leather jacket fish skin acellular matrix materials had porous and compact structure inside, and black fish skin acellular matrix materials had smooth structure inside. The H-E staining and Masson staining showed that leather jacket fish and black fish skin acellular matrix materials were both acellular collagen fibers. The hemolysis rates (the national standard ≤5%) of leather jacket fish and black fish skin acellular matrix material extracts were (1.23±0.43)% and (6.35±0.47)%, respectively. Human bone marrow-derived mesenchymal stem cells survived well in the culture medium containing extracts of leather jacket fish skin acellular matrix material, but most cells died or apoptozed in the culture medium containing extracts of Black fish skin acellular matrix material. Conclusion The leather jacket fish decellularized skin matrix material has better biosafety and biocompatibility, and has the potential to be a scaffold material for tissue engineering.
RESUMEN
Os papéis para fins sanitários são produtos absorventes compostos de fibras naturais, destinados à fabricação de papel higiênico, lenços, toalhas, guardanapos e lençóis hospitalares. Foram analisados 65 produtos de diferentes marcas de papéis comercializadas em São Paulo para avaliar a toxicidade dérmica utilizando-se ensaios in vivo e in vitro e a qualidade microbiológica. Foram utilizados ensaios recomendados pelas Norma ABNT NBR 15134-30/09/2004, Portaria 1480-31/12/1990 e Farmacopeia Americana. O ensaio in vivo foi realizado utilizando-se técnicas de Draize, Magnusson e Kligman; para o teste in vitro pela difusão em ágar foram empregadas as linhagens celulares NCTC clone 929 (ATCC-CCL1). Os produtos apresentaram resultados satisfatórios nos ensaios in vivo e in vitro. A qualidade microbiológica foi satisfatória em 49 (75,4%) amostras, porém em 16 (24,6%) amostras os resultados foram insatisfatórios pela presença de bactérias mesófilas aeróbias e de Clostridium spp. A técnica de citotoxicidade in vitro poderá ser utilizada como teste de triagem e como ensaio alternativo em substituição aos ensaios in vivo. Apesar da análise microbiológica não constar nas normas vigentes, o seu uso torna-se relevante para avaliar as condições higiênico-sanitárias e atender às normas de Boas Práticas de Fabricação e Controle.
Papers manufactured for sanitary purposes are absorbing products, composed by natural fibers, and usedto produce hygienic paper, handkerchiefs, towels, napkins, and hospital sheets. Sixty-five products fromdifferent manufacturers and marketed in São Paulo, Brazil were investigated by in vivo and in vitro dermal toxicity assays and microbiological quality analysis. The assays were performed following ABNT NBR 15134 Regulation and Ministerial Decree 1480. In vivo assay was carried out by Draize and Magnusson and Kligman techniques, and in vitro testing was performed by agar diffusion NCTC cell strains clone 929(ATCC-CCL1). Microbiological analysis was performed according to Ministerial Decree 1480. The analyzed products showed satisfactory results on both in vivo and in vitro assays. Forty-nine (75.4%) samples showed satisfactory microbiological quality, but unsatisfactory in 16 (24.6%) samples due to the occurrence of aerobicmesophilic bacteria and Clostridium spp. In vitro cytotoxicity assay could be used as screening test, and as an alternative test for replacing the animal-using methodologies. The microbiological analysis is not included in the pertinent guidelines, but the use of analytical marker is crucial for assessing the sanitary-hygienic conditions and also to act in compliance with Good Manufacturing and Control Practices.