Procedures for generating, collecting and extracting TPM from cigarette smoke have been established over the years as part of a CORESTA led study and have led to an ISO industry standard (ISO 4287:1991).
In brief, cigarettes are machine smoked to ISO standards (35 ml puff volume drawn over 2 seconds, once every minute, ISO 3308: 2000) on a smoke engine. Cigarettes are conditioned for a minimum of 72 hours prior to use (60±3% relative humidity, 22±1°C according to ISO 3402:1999). Particulate matter is collected onto a pre-weighed Cambridge filter pad which is placed in a smoke trap.
Filter pads are weighed after smoking to determine the weight of particulates accumulated onto the filter pad. A portion of the filter pad is taken for analysis of water and nicotine content [1,2].The remaining particulate matter can be extracted using a solvent such as methanol, ethanol, or dimethyl sulphoxide (DMSO). For our in vitro biological studies we use DMSO as the solvent. The TPM is eluted at a concentration of 24 mg/ml, protected from light and stored in single use aliquots at -20°C for up to 1 month. The TPM can be diluted to relevant working concentrations (typically 200µg/ml- 0.8µg/ml) and added to traditional submerged cell cultures and also to air-liquid interface cultures apically or basally to assess the effects of TPM using in vitro assays.