Photothermal-Responsive Conjugated Polymer Nanoparticles Triggered Precise Augmentation of Microalgal Photosynthesis

Exploring precise temperature-based photosynthesis regulation strategies will afford promising opportunities for controllable and efficient enhancement of photosynthesis. In this work, we developed a type of photothermal conjugated polymer nanoparticles (T-NPs) based on TZQ-TDPP (poly[2,5-bis(2-ethylhexyl)-3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-<i>c</i>]pyrrole-1,4-dione-<i>co</i>-(6,7-bis(4-((2-decyltetradecyl)oxy)phenyl) -[1,2,5] thiadiazolo[3,4-g]quinoxaline)]). T-NPs possess the desired photothermal conversion performance, with their photothermal conversion efficiency reaching up to 80.52%. The introduction of T-NPs enables the controllable regulation of the microenvironment temperature of <i>Chlorella pyrenoidosa</i> (<i>C. pyre</i>), thereby achieving accurate regulation on its photosynthetic activity. Under optimal conditions, T-NPs accelerate light-dependent reactions, leading to increased oxygen evolution and NADP⁺, NADPH, and ATP contents up to 46%, 20%, 23%, and 103%, respectively. Moreover, the Rubisco activity of <i>C. pyre</i> under light-independent reactions increased by 258%. The chlorophyll fluorimeter parameters and chlorophyll fluorescence kinetics curves also exhibited varying degrees of increase, demonstrating that the introduction of T-NPs improves the photosystem II (PSII)-related process and enhances the photosynthesis process of <i>C. pyre</i>. Integrated proteomic profiling revealed the regulatory mechanism of T-NPs on the photosynthesis of <i>C. pyre</i> and confirmed the upregulation of the Rubisco activity in <i>C. pyre</i>. This study provides a strategy for precise regulation of photosynthesis through photothermal-responsive conjugated polymer nanoparticles, advancing the development of photosynthetic organism-based sustainable energy and biomanufacturing.