Maldonado-Carmona Nidia, Marchand Guillaume, Villandier Nicolas, Ouk Tan-Sothea, Pereira Mariette M, Calvete Mário J F, Calliste Claude Alain, Żak Andrzej, Piksa Marta, Pawlik Krzysztof J, Matczyszyn Katarzyna, Leroy-Lhez Stéphanie
PEIRENE Laboratory, Faculty of Sciences and Techniques, University of Limoges, Limoges, France.
Laboratory of Catalysis and Fine Chemistry, Department of Chemistry, University of Coimbra, Coimbra, Portugal.
Front Microbiol. 2020 Nov 17;11:606185. doi: 10.3389/fmicb.2020.606185. eCollection 2020.
The need for alternative strategies to fight bacteria is evident from the emergence of antimicrobial resistance. To that respect, photodynamic antimicrobial chemotherapy steadily rises in bacterial eradication by using light, a photosensitizer and oxygen, which generates reactive oxygen species that may kill bacteria. Herein, we report the encapsulation of 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphyrin into acetylated lignin water-dispersible nanoparticles (), with characterization of those systems by standard spectroscopic and microscopic techniques. We observed that retained porphyrin's photophysical/photochemical properties, including singlet oxygen generation and fluorescence. Besides, the nanoparticles demonstrated enhanced stability on storage and light bleaching. were evaluated as photosensitizers against two Gram-negative bacteria, and , and against three Gram-positive bacteria, , , and . were able to diminish Gram-positive bacterial survival to 0.1% when exposed to low white LED light doses (4.16 J/cm), requiring concentrations below 5 μM. Nevertheless, the obtained nanoparticles were unable to diminish the survival of Gram-negative bacteria. Through transmission electron microscopy observations, we could demonstrate that nanoparticles did not penetrate inside the bacterial cell, exerting their destructive effect on the bacterial wall; also, a high affinity between acetylated lignin nanoparticles and bacteria was observed, leading to bacterial flocculation. Altogether, these findings allow to establish a photodynamic antimicrobial chemotherapy alternative that can be used effectively against Gram-positive topic infections using the widely available natural polymeric lignin as a drug carrier. Further research, aimed to inhibit the growth and survival of Gram-negative bacteria, is likely to enhance the wideness of acetylated lignin nanoparticle applications.
抗菌耐药性的出现表明，需要有替代策略来对抗细菌。在这方面，光动力抗菌化疗通过使用光、光敏剂和氧气稳步兴起，这些物质会产生活性氧，从而杀死细菌。在此，我们报道了将5,10,15,20-四(4-羟基苯基)-21H,23H-卟啉封装到乙酰化木质素水分散纳米颗粒中，并通过标准光谱和显微镜技术对这些体系进行了表征。我们观察到该纳米颗粒保留了卟啉的光物理/光化学性质，包括单线态氧的产生和荧光。此外，纳米颗粒在储存和光漂白方面表现出更高的稳定性。该纳米颗粒被评估为针对两种革兰氏阴性菌（大肠杆菌和铜绿假单胞菌）以及三种革兰氏阳性菌（金黄色葡萄球菌、枯草芽孢杆菌和粪肠球菌）的光敏剂。当暴露于低强度白色发光二极管光剂量（4.16 J/cm²）时，该纳米颗粒能够将革兰氏阳性菌的存活率降低至0.1%，所需浓度低于5 μM。然而，所获得的纳米颗粒无法降低革兰氏阴性菌的存活率。通过透射电子显微镜观察，我们可以证明纳米颗粒没有穿透细菌细胞内部，而是对细菌细胞壁产生破坏作用；此外，还观察到乙酰化木质素纳米颗粒与细菌之间具有高亲和力，导致细菌絮凝。总之，这些发现建立了一种光动力抗菌化疗替代方案，该方案可以使用广泛可得的天然聚合物木质素作为药物载体，有效对抗革兰氏阳性局部感染。旨在抑制革兰氏阴性菌生长和存活的进一步研究可能会扩大乙酰化木质素纳米颗粒的应用范围。
