Evaluating the cytotoxicity of Ge–Sb–Se chalcogenide glass optical fibres on 3T3 mouse fibroblasts

In vivo cancer detection based on the mid-infrared molecular fingerprint of tissue is promising for the fast diagnosis and treatment of suspected cancer patients. Few materials are mid-infrared transmissive, even fewer, which can be converted into functional, low-loss optical fibres for in vivo non-invasive testing. Chalcogenide-based glass optical fibres are, however, one of the few. These glasses are transmissive in the mid-infrared and are currently under development for use in molecular sensing devices. The cytotoxicity of these materials is however unknown. The cytotoxicity of Ge–Sb–Se chalcogenide optical glass fibres on 3T3 mouse fibroblast cells is here investigated. Fibres exposed to four different pre-treatment conditions are used: as-drawn (AD), propylamine-etched (PE), oxidised-and-washed (OW) and oxidised (Ox). To achieve the latter two conditions, fibres are treated with H2O2(aqueous (aq.)) and dried to produce a surface oxide layer; this is either washed off (OW) or left on the glass surface (Ox). Cellular response is investigated via 3 day elution and 14 day direct contact trials. The concentration of the metalloids (Ge, Sb and Se) in each leachate was measured via inductively coupled plasma mass spectrometry. Cell viability is assessed using the neutral red assay and scanning electron microscopy. The concentration of Ge, Sb and Se ions after a 3 day dissolution was as follows. In AD leachates, Ge: 0.40 mg L−1, Sb: 0.17 mg L−1, and Se: 0.06 mg L−1. In PE leachates, Ge: 0.22 mg L−1, Sb: 0.15 mg L−1, and Se: 0.02 mg L−1. In Ox leachates, Ge: 823.8 mg L−1, Sb: 2586.6 mg L−1, and Se: 3750 mg L−1. Direct contact trials show confluent cell layers on AD, PE and OW fibres after 14 days, while no cells are observed on the Ox surfaces. A >50% cell viability is observed in AD, PE and OW eluates after 3 days, when compared with Ox eluates

Preclinical Models of Wound Healing: Is Man the Model? Proceedings of the Wound Healing Society Symposium

SIGNIFICANCE: A review of therapeutic effects in preclinical and clinical studies suggests that concordance between large animal (pig=78%), small laboratory animal (53%) and in vitro (57%) results with those observed in humans is only partial. Pig models of wound healing provide major advantages over other animal models. Since the vast majority of wound-healing research is done in rodents and in vitro, the low concordance rate is a significant impediment to research that will have any clinical impact. CRITICAL ISSUES: To generate clinically relevant experimental data, hypothesis generation should begin, or at least involve human wound tissue samples. Such tissue could be used to test a predetermined hypothesis generated based on, say, murine data. Alternatively, such tissue could be analyzed using high-throughput cell biology techniques (e.g., genomics, proteomics, or metabolomics) to identify novel mechanisms involved in human wounds. Once the hypothesis has been formulated and confirmed using human samples, identification of these same mechanisms in animals represents a valid approach that could be used for more in-depth investigations and experimental manipulations not feasible with humans. FUTURE DIRECTIONS: This consensus statement issued by the Wound Healing Society symposium strongly encourages all wound researchers to involve human wound tissue validation studies to make their animal and cell biology studies more translationally and clinically significant