RESUMO
We designed and synthesized two analogous pentacationic [60]fullerenyl monoadducts, C60(>ME1N6âºC3) (1) and C60(>ME3N6âºC3) (2), with variation of the methoxyethyleneglycol length. Each of these derivatives bears a well-defined number of cationic charges aimed to enhance and control their ability to target pathogenic Gram-positive and Gram-negative bacterial cells for allowing photodynamic inactivation. The synthesis was achieved by the use of a common synthon of pentacationic N,N',N,N,N,N-hexapropylhexa(aminoethyl)amine arm (C3N6âº) having six attached propyl groups, instead of methyl or ethyl groups, to provide a well-balanced hydrophobicity-hydrophilicity character to pentacationic precursor intermediates and better compatibility with the highly hydrophobic C60 cage moiety. We demonstrated two plausible synthetic routes for the preparation of 1 and 2 with the product characterization via various spectroscopic methods.
Assuntos
Antibacterianos/síntese química , Cátions/química , Fulerenos/química , Fármacos Fotossensibilizantes/síntese química , Antibacterianos/análise , Fulerenos/análise , Humanos , Interações Hidrofóbicas e Hidrofílicas , Luz , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Fotoquimioterapia , Fármacos Fotossensibilizantes/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade EstáticaRESUMO
Novel water-soluble decacationically armed C(60) and C(70) decaiodide monoadducts, C(60)- and C(70)[>M(C(3)N(6)(+)C(3))(2)], were synthesized, characterized, and applied as photosensitizers and potential nano-PDT agents against pathogenic bacteria and cancer cells. A high number of cationic charges per fullerene cage and H-bonding moieties were designed for rapid binding to the anionic residues displayed on the outer parts of bacterial cell walls. In the presence of a high number of electron-donating iodide anions as parts of quaternary ammonium salts in the arm region, we found that C(70)[>M(C(3)N(6)(+)C(3))(2)] produced more HO(â¢) than C(60)[>M(C(3)N(6)(+)C(3))(2)], in addition to (1)O(2). This finding offers an explanation of the preferential killing of Gram-positive and Gram-negative bacteria by C(60)[>M(C(3)N(6)(+)C(3))(2)] and C(70)[>M(C(3)N(6)(+)C(3))(2)], respectively. The hypothesis is that (1)O(2) can diffuse more easily into porous cell walls of Gram-positive bacteria to reach sensitive sites, while the less permeable Gram-negative bacterial cell wall needs the more reactive HO(â¢) to cause real damage.
Assuntos
Antineoplásicos/farmacologia , Bactérias/efeitos dos fármacos , Fulerenos/farmacologia , Iodetos/farmacologia , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/farmacologia , Compostos de Amônio Quaternário/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Estabilidade de Medicamentos , Fulerenos/química , Células HeLa , Humanos , Iodetos/síntese química , Iodetos/química , Espectroscopia de Ressonância Magnética , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/química , Compostos de Amônio Quaternário/síntese química , Compostos de Amônio Quaternário/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrofotometria UltravioletaRESUMO
We report the synthesis of a new class of photoresponsive C(60)-DCE-diphenylaminofluorene nanostructures and their intramolecular photoinduced energy and electron transfer phenomena. Structural modification was made by chemical conversion of the keto group in C(60)(>DPAF-C(n)) to a stronger electron-withdrawing 1,1-dicyanoethylenyl (DCE) unit leading to C(60)(>CPAF-C(n)) with an increased electronic polarization of the molecule. The modification also led to a large bathochromic shift of the major band in visible spectrum giving measureable absorption up to 600 nm and extended the photoresponsive capability of C(60)-DCE-DPAF nanostructures to longer red wavelengths than C(60)(>DPAF-C(n)). Accordingly, C(60)(>CPAF-C(n)) may allow 2γ-PDT using a light wavelength of 1000-1200 nm for enhanced tissue penetration depth. Production efficiency of singlet oxygen by closely related C(60)(>DPAF-C(2) (M)) was found to be comparable with that of tetraphenylporphyrin photosensitizer. Remarkably, the (1)O(2) quantum yield of C(60)(>CPAF-C(2) (M)) was found to be nearly 6-fold higher than that of C(60)(>DPAF-C(2) (M)), demonstrating the large light-harvesting enhancement of the CPAF-C(2) (M) moiety and leading to more efficient triplet state generation of the C(60)> cage moiety. This led to highly effective killing of HeLa cells by C(60)(>CPAF-C(2) (M)) via photodynamic therapy (200 J cm(-2) white light). We interpret the phenomena in terms of the contributions by the extended π-conjugation and stronger electron-withdrawing capability associated with the 1,1-dicyanoethylenyl group compared to that of the keto group.