title: Toxicity evaluation of e-juice and its soluble aerosols generated by electronic cigarettes using recombinant bioluminescent bacteria responsive to specific cellular damages.
abstract: Electronic-cigarettes (e-cigarette) are widely used as an alternative to traditional cigarettes but their safety is not well established. Herein, we demonstrate and validate an analytical method to discriminate the deleterious effects of e-cigarette refills (e-juice) and soluble e-juice aerosol (SEA) by employing stress-specific bioluminescent recombinant bacterial cells (RBCs) as whole-cell biosensors. These RBCs carry luxCDABE-operon tightly controlled by promoters that specifically induced to DNA damage (recA), superoxide radicals (sodA), heavy metals (copA) and membrane damage (oprF). The responses of the RBCs following exposure to various concentrations of e-juice/SEA was recorded in real-time that showed dose-dependent stress specific-responses against both the e-juice and vaporized e-juice aerosols produced by the e-cigarette. We also established that high doses of e-juice (4-folds diluted) lead to cell death by repressing the cellular machinery responsible for repairing DNA-damage, superoxide toxicity, ion homeostasis and membrane damage. SEA also caused the cellular damages but the cells showed enhanced bioluminescence expression without significant growth inhibition, indicating that the cells activated their global defense system to repair these damages. DNA fragmentation assay also revealed the disintegration of total cellular DNA at sub-toxic doses of e-juice. Despite their state of matter, the e-juice and its aerosols induce cytotoxicity and alter normal cellular functions, respectively that raises concerns on use of e-cigarettes as alternative to traditional cigarette. The ability of RBCs in detecting both harmful effects and toxicity mechanisms provided a fundamental understanding of biological response to e-juice and aerosols.
authors.affiliation: Sabanci University Nanotechnology Research and Application Center, Orta Mahalle 34956, Tuzla, Istanbul, Turkey.
authors.forename: Shiv
authors.initials: S
authors.lastname: Bharadwaj
authors.affiliation: School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan 689-798, Republic of Korea.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Mitchell
authors.affiliation: Sabanci University Nanotechnology Research and Application Center, Orta Mahalle 34956, Tuzla, Istanbul, Turkey.
authors.forename: Anjum
authors.initials: A
authors.lastname: Qureshi
authors.affiliation: Sabanci University Nanotechnology Research and Application Center, Orta Mahalle 34956, Tuzla, Istanbul, Turkey. Electronic address: javed@sabanciuniv.edu.
authors.forename: Javed H
authors.initials: JH
authors.lastname: Niazi
mesh_terms: D000336:Aerosols / Q000737:chemistry; D001419:Bacteria / Q000187:drug effects* / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D015374:Biosensing Techniques; D004249:DNA Damage / Q000187:drug effects*; D004274:DNA, Recombinant / Q000737:chemistry / Q000235:genetics; D066300:Electronic Nicotine Delivery Systems / Q000009:adverse effects*; D006801:Humans; D010088:Oxidoreductases / Q000235:genetics; D011938:Rec A Recombinases / Q000235:genetics
chemical_list: D000336:Aerosols; D001426:Bacterial Proteins; C071263:CopA protein, Bacteria; D004274:DNA, Recombinant; D010088:Oxidoreductases; C055198:LuxC protein, Bacteria; D011938:Rec A Recombinases
keywords: Bioluminescence; Biosensor; E-cigarette; E-juice; Toxicity; lux