Efficient two-step excitation energy transfer in artificial light-harvesting antenna based on bacteriochlorophyll aggregates

• Published in: Journal of photochemistry and photobiology. B, Biology Biology, 2024-05, Vol.254, p.112891-112891, Article 112891
• Main Authors: Malina, Tomáš, Bína, David, Collins, Aaron M., Alster, Jan, Pšenčík, Jakub
• Format: Article
• Language: English
• Subjects: Artificial light-harvesting antenna; Bacteriochlorophyll aggregates; Chlorosomes; Efficiency of excitation energy transfer; Fluorescence spectroscopy
• ISSN: 1011-1344; 1873-2682
• DOI: 10.1016/j.jphotobiol.2024.112891

Chlorosomes of green photosynthetic bacteria are large light-harvesting complexes enabling these organisms to survive at extremely low-light conditions. Bacteriochlorophylls found in chlorosomes self-organize and are ideal candidates for use in biomimetic light-harvesting in artificial photosynthesis and other applications for solar energy utilization. Here we report on the construction and characterization of an artificial antenna consisting of bacteriochlorophyll c co-aggregated with β-carotene, which is used to extend the light-harvesting spectral range, and bacteriochlorophyll a, which acts as a final acceptor for excitation energy. Efficient energy transfer between all three components was observed by means of fluorescence spectroscopy. The efficiency varies with the β-carotene content, which increases the average distance between the donor and acceptor in both energy transfer steps. The efficiency ranges from 89 to 37% for the transfer from β-carotene to bacteriochlorophyll c, and from 93 to 69% for the bacteriochlorophyll c to bacteriochlorophyll a step. A significant part of this study was dedicated to a development of methods for determination of energy transfer efficiency. These methods may be applied also for study of chlorosomes and other pigment complexes. •A three-component self-assembling artificial light-harvesting antenna was prepared.•The antenna is based on bacteriochlorophyll aggregates from chlorosomes.•β-carotene was used to extend the spectral coverage of the aggregates.•Bacteriochlorophyll a was used as the final acceptor of the excitation.•Methods for determination of energy transfer efficiency in the antenna were developed.