Vitrocell® high throughput exposure Module 2.0+: deposition of whole aerosol from two different tobacco product types
The continued development of exposure systems provides a means to conduct in vitro assessment of freshly generated whole aerosol from both heated tobacco products (HTP) and electronic nicotine delivery systems (ENDS). A challenge with such exposure systems is ensuring sufficient sample throughput for in vitro toxicological studies in a timely manner. Vitrocell has developed high throughput whole smoke/aerosol exposure modules designed to deliver up to seven doses of whole smoke/aerosol plus a clean air control concurrently onto 12mm or 24mm Transwell® inserts. Initial characterization of this exposure system was conducted using a series of experiments designed to assess the delivery of whole aerosol from a commercially available HTP or ENDS. A Vitrocell VC1/7 smoking robot was used to deliver aerosol generated under ISO 20788:2018 regimen (55 mL puff, 2 sec puff duration, 30 sec puff interval) or a modified ISO 20768:2018 (55 mL puff, 3 sec puff duration, 30 sec puff interval, with a 60 sec pause every 10 puffs) for HTP or ENDS, respectively, to the exposure modules. Aerosol concentrations were controlled using serial dilution airflows ranging from 0 (undiluted) to 4 L/min and the deposition was quantified using aerosol photometers and chemical analysis (e.g., glycerol) of PBS traps within the modules. Intra-experimental free glycerol deposition was largely within ±15% for both module and product types. Free glycerol vs. photometer area under the curve linear regression R2 values were >0.8 for all experiments. Overall, the Vitrocell 48 2.0+ exposure module will be a useful tool to increase sample throughput for the in vitro toxicological assessment of freshly generated whole aerosols from different tobacco product types.