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Cytotoxicity assessment of combustible tobacco products by neutral red uptake (NRU) has historically used total particulate matter (TPM) or solvent captured gas vapor phase (GVP), rather than fresh whole smoke. Here, the development, validation and application of the NRU assay in Chinese Hamster Ovary (CHO) cells, following exposure to fresh whole smoke generated with the VITROCELL® VC10® system is described. Whole smoke exposure is particularly important as both particulate and vapor phases of tobacco smoke show cytotoxicity in vitro. The VITROCELL® VC10® system provides exposure at the air liquid interface (ALI) to mimic in vivo conditions for assessing the toxicological impact of smoke in vitro. Instrument and assay validations are crucial for comparative analyses. Goals of this study: 1) demonstrate functionality of the VITROCELL® VC10® system by installation, operational and performance qualification, 2) develop and validate a cellular system for assessing cytotoxicity following whole smoke exposure and 3) assess the whole smoke NRU assay sensitivity for statistical differentiation between a reference combustible cigarette (3R4F) and a primarily “heat-not-burn” cigarette (Eclipse). Results The VITROCELL® VC10® provided consistent generation and delivery of whole smoke; exposure-related changes in in vitro cytotoxicity were observed with reproducible IC50 values; comparative analysis showed that the heat-not-burn cigarette was significantly (P

The assessment of potential cytotoxicity or genotoxicity of combustible tobacco products has historically been performed using partitioned exposures (i.e. total particulate matter [TPM], gas vapor phase [GVP]) rather than whole smoke. The VITROCELL® VC10® smoke exposure system offers multiple platforms for air liquid interface (ALI) or air agar interface (AAI) exposure to mimic in vivo-like conditions for assessing the toxicological impact of whole smoke using in vitro assays (e.g. cytotoxicity, mutagenicity and DNA modifications). The aims of this study were to investigate dosimetry during whole smoke exposure in the VITROCELL® VC10® smoking robot using quartz crystal microbalances (QCMs) and to support the use of photometers for concurrent assessment of ‘dose’ during whole smoke exposures. QCM results showed consistent deposition across different exposure chambers, between dilution bars, experiments and modules. Higher levels of variation were noted at higher airflows (i.e., >8 L/min). Dosimetry assessed using photometers also showed a high level of consistency between experiments, with no notable impact on deposition on the QCM when the photometers were placed ‘in-line’ between the dilution bar and the exposure module. However, the use of photometers alone may be not be sufficient to estimate deposition; the predictability of the data-generated equation was poor. Further development of dosimetry methodology and information for use in validated in vitro biological test methods is needed to facilitate on-going aerosol-based research and relative assessment.

As part of the movement to greater social inclusion, a number of initiatives have been created to build bridges between the school and further education sectors and universities. In England, this k...