Although utilization of engineered nanomaterials (ENM) due to expansion of the science and application of nanobiomedicine/technology is expected to markedly increase, the mechanisms by which ENM injure and/or are transported into/across lung alveolar epithelium are not well known. Inhalation of ambient ultrafine particulates (whose size range overlaps the current definition of nanomaterials) has been shown to result in adverse cardiovascular, pulmonary and hematologic effects. If any ENM are accidently inhaled, their most likely route of entry into the systemic circulation is across the alveolar epithelium of the lung. Based on our ongoing research on lung injury and trafficking of several (e.g., polystyrene, silica and metal (oxides)) classes of nanoparticles with defined physicochemical characteristics, and recent reports on health effects of inhaled ultrafine air pollutant particulates and other nanomaterials (especially fullerenes and their derivatives), we hypothesize that interactions between various forms of ENM (e.g., negative vs. positive fullerenes;pristine (hydrophobic) vs. derivatized (hydrophilic) fullerenes;fullerenes of different mass (e.g., C60, C70, vs. C80 vs. polymeric fullerenes) and alveolar epithelial cells i) can disrupt normal alveolar epithelial cell homeostasis and induce changes in cellular properties and alveolar epithelial barrier function in an ENM-specific manner, ii) can provide the primary portal of entry for ENM into the systemic circulation (e.g., fullerenes may be translocated via transepithelial translocation pathways), and iii) are highly dependent on physicochemical properties of ENM (e.g., fullerenes). Utilizing fullerenes of appropriately modified surface characteristics in in vitro models (including our well-established primary cultured monolayers of rat alveolar epithelial cells) and rat lungs in vivo, we will test these hypotheses by investigating the following four aims: 1) effects of apically exposing fullerenes on active and passive barrier properties of alveolar epithelium in vitro;2) internalization, fate and effects of fullerenes in alveolar epithelial cells in vitro;3) trafficking of fullerenes across alveolar epithelium in vitro;and 4) fullerene internalization and trafficking in rat lungs in vivo, correlating injury to and trafficking across distal respiratory epithelium in vivo vs. in vitro. Findings from the investigations proposed herein will provide insights into cytotoxicity and mechanisms of internalization/trafficking of fullerenes with defined physicochemical properties into/across lung alveolar epithelium. Our major objective is to obtain new information on fullerene (and other ENM) interactions with alveolar epithelium in order to help understand interactions with the lung, and help improve future nanobiomedical applications (e.g., pulmonary drug/gene delivery).
Inhalation of man-made nanomaterials (<100 nm in diameter), including ultrafine ambient pollutant particles and engineered/manufactured nanomaterials (ENM: examples are fullerenes (composed of >60 carbon atoms), carbon nanotubes (CNT), quantum dots and metal /metal oxide nanoparticles), may be associated with various heart-, blood- and lung-related health effects. It appears that these effects may increase morbidity and mortality in susceptible populations. Of these nanomaterials, fullerenes have been manufactured in an astonishingly large quantity for wide applications, yet the mechanisms by which this particular ENM (e.g., fullerenes with positive vs. negative surface charges and/or pristine (lipid-loving) vs. derivatized (water-loving)) injure and/or are translocated into and/or across alveolar epithelium (where gas exchange and ion transport occur in the distal portion of the lung) are not well understood. We will determine interactions with both in vitro and in vivo rat models of the distal air-blood barrier of the lung (i.e., alveolar epithelium) in order to help understand possible injury from inhaled fullerenes with defined surface properties (e.g., charge and hydrophobicity). With this knowledge, improved nanomedical and biological applications (e.g., drug/gene delivery) using fullerenes bearing specific surface properties (that do not cause injury) can be designed for future applications.
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