Ber textiles exposed to irradiation for indicated times. The values are counted from 5 representative fields containing approximately 130 cells. doi:10.1371/journal.pone.0049226.gVirucidal Nanofiber TextilesFigure 8. Inactivation of the mouse polyomavirus and the recombinant baculovirus in aqueous solutions of TPPS. Percentages of infected cells by the mouse polyomavirus (a,b) or the recombinant baculovirus (c,d) previously incubated for 30 minutes in solutions of indicated concentrations of TPPS in the dark (a,c) and after irradiation (b,d). The values are counted from 5 representative fields containing approximately 130 cells. doi:10.1371/journal.pone.0049226.gThe crucial requirement for O2(1Dg)-mediated protein damage to occur efficiently is localization of amino acid residues sensitive to O2(1Dg) on the surface of compact inhibitor capsid structures. The crystal structures of MPyV and Simian virus 40 (SV40) have been determined. The capsid shell of the polyomavirus used in this study is composed of 72 pentamers of the major structural protein VP1 (Fig. 9). Two other minor structural proteins, VP2 and VP3, are not exposed on surface of the capsid. VP1 from both polyomaviruses contains a b-sandwich core with several outfacing loops [38,39]. 
These interactive loops are exposed on the surface of VP1 pentamers and polyomavirus capsids. Computer analysis revealed the presence of several tyrosine and tryptophan residues as 
well as one histidine and one methionine residue in the surface loops. Many other sensitive amino acid residues occurring in the VP1 b-sandwich core might be less accessible. The level of accessibility of the amino acid residues that are sensitive to O2(1Dg) can differ among capsid proteins of nonenveloped viruses, and it will be necessary to test the efficiency of their inactivation individually. Recently, efficient inactivation of the Autophagy non-enveloped bacteriophage MS-2 by visible light was reported based on using a cationic fullerene derivative with amine functionality as a photosensitizer to produce O2(1Dg) [40]. Based on the computer analysis of capsid subunits from viruses with known tertiary structures, we predict that human papillomaviruses or poliovirus can be efficiently inactivated by O2(1Dg) produced by the photosensitizer used in this study. Thus, the photosensitizersimmobilized on the nanofibers can be highly useful for the development of novel approaches for inactivating both enveloped and non-enveloped viruses.ConclusionsThis study, addressing the photophysical, photochemical and photovirucidal properties of polymer nanofibers based on the TecophilicH thermoplastic polyurethane and polycaprolactone with an encapsulated 5,10,5,20-tetraphenylporphyrin photosensitizer, reveals that these textiles are efficient sources 15900046 of short-lived virucidal O2(1Dg). The photoproduction and lifetime of O2(1Dg) in these materials are sufficient to exert strong photovirucidal effects on non-enveloped polyomaviruses and enveloped baculoviruses on the surface of the nanofiber textiles. These new nanomaterials could be considered for use in a number of medical applications and for the development of O2(1Dg) inactivation tests for enveloped and non-enveloped viruses.Materials and Methods Chemicals5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetrakis(4sulfonatophenyl)porphyrin (TPPS), 9,10-anthracenediyl-bis(methylene)dimalonic acid (AMA) and tetraethylammonium bromide (TEAB) were purchased from Aldrich (USA). Formic acid, acetic acid, N,.Ber textiles exposed to irradiation for indicated times. The values are counted from 5 representative fields containing approximately 130 cells. doi:10.1371/journal.pone.0049226.gVirucidal Nanofiber TextilesFigure 8. Inactivation of the mouse polyomavirus and the recombinant baculovirus in aqueous solutions of TPPS. Percentages of infected cells by the mouse polyomavirus (a,b) or the recombinant baculovirus (c,d) previously incubated for 30 minutes in solutions of indicated concentrations of TPPS in the dark (a,c) and after irradiation (b,d). The values are counted from 5 representative fields containing approximately 130 cells. doi:10.1371/journal.pone.0049226.gThe crucial requirement for O2(1Dg)-mediated protein damage to occur efficiently is localization of amino acid residues sensitive to O2(1Dg) on the surface of compact capsid structures. The crystal structures of MPyV and Simian virus 40 (SV40) have been determined. The capsid shell of the polyomavirus used in this study is composed of 72 pentamers of the major structural protein VP1 (Fig. 9). Two other minor structural proteins, VP2 and VP3, are not exposed on surface of the capsid. VP1 from both polyomaviruses contains a b-sandwich core with several outfacing loops [38,39]. These interactive loops are exposed on the surface of VP1 pentamers and polyomavirus capsids. Computer analysis revealed the presence of several tyrosine and tryptophan residues as well as one histidine and one methionine residue in the surface loops. Many other sensitive amino acid residues occurring in the VP1 b-sandwich core might be less accessible. The level of accessibility of the amino acid residues that are sensitive to O2(1Dg) can differ among capsid proteins of nonenveloped viruses, and it will be necessary to test the efficiency of their inactivation individually. Recently, efficient inactivation of the non-enveloped bacteriophage MS-2 by visible light was reported based on using a cationic fullerene derivative with amine functionality as a photosensitizer to produce O2(1Dg) [40]. Based on the computer analysis of capsid subunits from viruses with known tertiary structures, we predict that human papillomaviruses or poliovirus can be efficiently inactivated by O2(1Dg) produced by the photosensitizer used in this study. Thus, the photosensitizersimmobilized on the nanofibers can be highly useful for the development of novel approaches for inactivating both enveloped and non-enveloped viruses.ConclusionsThis study, addressing the photophysical, photochemical and photovirucidal properties of polymer nanofibers based on the TecophilicH thermoplastic polyurethane and polycaprolactone with an encapsulated 5,10,5,20-tetraphenylporphyrin photosensitizer, reveals that these textiles are efficient sources 15900046 of short-lived virucidal O2(1Dg). The photoproduction and lifetime of O2(1Dg) in these materials are sufficient to exert strong photovirucidal effects on non-enveloped polyomaviruses and enveloped baculoviruses on the surface of the nanofiber textiles. These new nanomaterials could be considered for use in a number of medical applications and for the development of O2(1Dg) inactivation tests for enveloped and non-enveloped viruses.Materials and Methods Chemicals5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetrakis(4sulfonatophenyl)porphyrin (TPPS), 9,10-anthracenediyl-bis(methylene)dimalonic acid (AMA) and tetraethylammonium bromide (TEAB) were purchased from Aldrich (USA). Formic acid, acetic acid, N,.
