Desenvolvimento, caracterização e efeitos fotodinâmicos de Curcumina em micela copolimérica fotoativada para Terapia Fotodinâmica antimicrobiana
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Data
2020-12-17
Autores
Trigo‐Gutierrez, Jeffersson Krishan [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Os nanocarregadores tém sido utilizados com sucesso para a veiculação de curcumina (CUR). No entanto, a demorada liberação do composto limita seu uso tópico como fotossensibilizador (FS) para Terapia Fotodinâmica antimicrobiana (aPDT), na qual ainda são necessários longos tempos de pré-iluminação e iluminação. Assim, o objetivo deste estudo foi desenvolver um sistema micelar fotoativado para liberação de CUR. As micelas foram sintetizadas pelo método de adição direta utilizando o polímero fotossensível formado por poli-etileno glicol como polímero e ácido 3-nitro-4-bromometilbenzoico como cromóforo e ácido fenoxiacético como extremo apolar (PEG-ANB-AFA), denominado polímero fotossensível (PFS). Adicionalmente, como controles, foram sintetizadas micelas convencionais de Pluronic® F127 ou P123. Os testes de caracterização por espectroscopia de absorção e fluorescência incluíram: determinação da Concentração Micelar Crítica, constante de ligação e supressão de fluorescência. As micelas de PFS apresentaram maior eficiência de encapsulamento (88,79%), enquanto que, para as micelas convencionais, foram observados valores de 77,52% para F127 e 72,58% para micelas de P123. O PFS apresentou fotodegradação gradativa com irradiação UV a 355 nm, fato que facilitou a liberação da CUR de dentro das micelas, o que melhorou a demorada liberação do sistema convencional. Os tamanhos na faixa nanométrica de 40,42; 22,90 e 20,78 nm para as micelas de PFS, F127 e P123 respectivamente, e índice de polidispersão de até 0,392 u.a. foram determinadas por meio da técnica de espalhamento dinâmico da luz, e por Microscopia Eletrônica de Varredura com Emissão de Campo foram observadas micelas esféricas. A potêncial zeta aniônico (de -0,139 a -0,613 mV) dos três sistemas foi determinada por meio do potencial zeta. Os efeitos fotodinâmicos do FS na micela fotoativada bem como em micelas convencionais e CUR livre em aPDT contra culturas planctônicas de Candida albicans e Pseudomonas aeruginosa demonstraram diminuição de 1 Log10 comparado com os respectivos grupos controle (diferença significativa p<0,05). Já em culturas planctônicas Staphylococcus aureus resistente à meticilina (MRSA) a micela fotoativada demostrou maior efeito fotodinâmico antimicrobiano que os sistemas convencionais diminuindo a contagem de colônias 2 Log10 comparado com o grupo controle (diferença significativa p<0,05). Adicionalmente, a aPDT promoveu diminuição da biomassa dos biofilmes de MRSA e C. albicans, comparados com seus respetivos grupos controle (diferença significativa p<0,05). Finalmente, as micelas foto-ativadas não apresentaram toxicidade em queratinócitos orais. Desta forma, a aPDT mediada pela CUR em micelas foto-ativadas pode ser uma alternativa para o tratamento de infecções microbianas.
Nanocarriers have been used successfully for delivery of curcumin (CUR); however, slow release from nanosystems hinders its use as topical photosensitizer (PS) in antimicrobial Photodynamic Therapy (aPDT), which requires long pre-irradiation times. Light-triggered nanosystems are an interesting option, since they allow remote temporal control of drug release. Thus, in this research a photo-responsive micelle (PRM) was synthesized to carry CUR. The PRM were synthesized by direct adittion method using the photoresponsive polymer formed by poly (ethylene glycol), 3-nytro- 4-bromobenzilic acid as chromophore and phenoxiacetic acid as apolar segment. Moreover, conventional micelles synthesized from commercial Pluronic® P123 and F127 as control micelles. The charachterization of the micelles by fluorescence and absorbance spectroscopy were Critical Micellar Concentration, binding of PRM to CUR, and fluorescence quenching. The Entrapment Efficiency (EE%) was also higher in PRM (88.79%), on the other hand, a similar EE% were observed between F127 and P123 micelles (77.52 and 72.58% respectively). Furthermore, degradation of the absorption spectra of PRM was observed, allowing CUR being released from the PRM, thus the slow release from the nanosystem was improved. Dynamic light scaterring, and Scanning Electronic Microscopy, showed the micelles size on the nanometric scale (40.42, 22.90, and 20.78 for PRM, F127 and P123 micelles, respectievely), and high homogeneity of the systems (to 0.392). The Field Emission Scanning Electronic Microscopy showed spherical shape micelles. The zeta potential of the three systems were anionic (from -0.139 to -0.613 mV). The aPDT mediated CUR-loaded PRM as well as conventional micelles and free CUR against planktonic cultures of methicillin resistant Staphylococcus aureus (MRSA), Candida albicans, and Pseudomonas aeruginosa were evaluated. In C. albicans, and P. aeruginosa aPDT mediated by PRM, conventional micelles and free CUR promoted diminution of 1 Log in colony count compared with the control group (p<0.05). In MRSA the aPDT mediated by PRM promotes diminution of 2 Log compared to the control group (p<0.05). While in groups aPDT treated with conventional micelles and free CUR diminution of 1 Log compared with the control group was observed (p<0.05). Moreover, the aPDT mediadted by CUR in PRM decreased the biomass in single biofilm of MRSA and C. albicans –significant diference of p<0.05 compared to their respective control groups. Furthermore, the PRM did not show toxic effect on Normal Oral Keratinocites cells. Thus, PRM could be an alternative to treat microbial infections.
Nanocarriers have been used successfully for delivery of curcumin (CUR); however, slow release from nanosystems hinders its use as topical photosensitizer (PS) in antimicrobial Photodynamic Therapy (aPDT), which requires long pre-irradiation times. Light-triggered nanosystems are an interesting option, since they allow remote temporal control of drug release. Thus, in this research a photo-responsive micelle (PRM) was synthesized to carry CUR. The PRM were synthesized by direct adittion method using the photoresponsive polymer formed by poly (ethylene glycol), 3-nytro- 4-bromobenzilic acid as chromophore and phenoxiacetic acid as apolar segment. Moreover, conventional micelles synthesized from commercial Pluronic® P123 and F127 as control micelles. The charachterization of the micelles by fluorescence and absorbance spectroscopy were Critical Micellar Concentration, binding of PRM to CUR, and fluorescence quenching. The Entrapment Efficiency (EE%) was also higher in PRM (88.79%), on the other hand, a similar EE% were observed between F127 and P123 micelles (77.52 and 72.58% respectively). Furthermore, degradation of the absorption spectra of PRM was observed, allowing CUR being released from the PRM, thus the slow release from the nanosystem was improved. Dynamic light scaterring, and Scanning Electronic Microscopy, showed the micelles size on the nanometric scale (40.42, 22.90, and 20.78 for PRM, F127 and P123 micelles, respectievely), and high homogeneity of the systems (to 0.392). The Field Emission Scanning Electronic Microscopy showed spherical shape micelles. The zeta potential of the three systems were anionic (from -0.139 to -0.613 mV). The aPDT mediated CUR-loaded PRM as well as conventional micelles and free CUR against planktonic cultures of methicillin resistant Staphylococcus aureus (MRSA), Candida albicans, and Pseudomonas aeruginosa were evaluated. In C. albicans, and P. aeruginosa aPDT mediated by PRM, conventional micelles and free CUR promoted diminution of 1 Log in colony count compared with the control group (p<0.05). In MRSA the aPDT mediated by PRM promotes diminution of 2 Log compared to the control group (p<0.05). While in groups aPDT treated with conventional micelles and free CUR diminution of 1 Log compared with the control group was observed (p<0.05). Moreover, the aPDT mediadted by CUR in PRM decreased the biomass in single biofilm of MRSA and C. albicans –significant diference of p<0.05 compared to their respective control groups. Furthermore, the PRM did not show toxic effect on Normal Oral Keratinocites cells. Thus, PRM could be an alternative to treat microbial infections.
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Fotoquimioterapia, Bactérias, Fungos, Luz