Summary

Mammalian eyes are exposed to visible light but cannot perform photosynthesis. Here, we show that introducing a nanoscale, structurally and functionally preserved thylakoid system, LEAF (light-reaction enriched thylakoid NADPH-foundry), into corneal cells enables light-driven bona fide photosynthetic production of NADPH and ATP, similar to plant leaves, which alleviates oxidative stress and inflammation. LEAF acts in two domains. Intracellularly, it integrates with host cells to supply NADPH and ATP via intact photosynthetic electron transport, restoring redox balance. Extracellularly, photosynthesized NADPH enhances endogeneous antioxidant enzyme activity and reduces reactive oxygen species in the local environment. These results establish a strategy for using light as an energy input in mammalian metabolic systems and suggest a possible cross-kingdom, endosymbiosis-like interaction in which animal cells derive functional benefits from plant-derived photosynthetic neo-organelles.

Abstract

Purple bacteria are a diverse group of photosynthetic organisms that can capture and convert light energy with high quantum efficiency across a variety of ecological niches. They absorb light via an array of antenna proteins, primarily light-harvesting complex 2 (LH2), and rapidly transport the energy to the reaction center, where charge separation occurs. LH2 typically consists of eight or nine subunits that each contain three bacteriochlorophyll and one carotenoid. In the marine species Marichromatium (Mch.) purpuratum, the LH2 subunits bind an additional carotenoid, boosting absorbance in the blue where the underwater solar spectrum peaks. In order to accommodate the additional carotenoid, LH2 from Mch. purpuratum consists of only seven subunits, unique among known LH2. Using ultrafast transient absorption (TA) spectroscopy, time-resolved fluorescence, and steady-state techniques, we investigated the effects of these structural differences on the energy transfer dynamics of LH2 from Mch. purpuratum. Our results show, relative to other species, significantly slower rates of energy transfer within LH2 and an excited-state manifold likely to also slow energy transfer between LH2. LH2 from Mch. purpuratum is therefore tuned to match the solar spectrum of its ecological niche, suggesting that the variations in the molecular organization of these antenna proteins may be primarily for optimal light absorption.

Abstract

Sea slugs in the Sacoglossa superorder are some of the few animals capable of photosynthesising by isolating and maintaining functional chloroplasts within their body. While this ability allows some species in this superorder, such as Elysia viridis, to appear green, camouflaging themselves within their surroundings, this species is marked by extremely bright, coloured regions.

Here, we show that these animals produce a yet undiscovered class of photonic structure consisting of intracellular mixed amorphous CaCO3 and calcite spherical nanoparticles organised in non-closed-packed face-centred cubic (FCC) lattices and photonic glasses.

By mapping the distribution of the cells containing such architectures, we suggest that their colour is linked both to their function and to their biological formation via the animal's renal system. Using a combination of different optical methods and cryo-electron microscopy, we reveal that the biomineralisation pathway proceeds through stages of calcium ion concentration in the kidney, transport via internal vessels, and precipitation from a dense liquid-like precursor, culminating in the formation of monodisperse nanoparticles, which are the building blocks of these photonic structures.

Abstract

The design of efficient artificial light-harvesting antennas is essential for enabling the widespread use of solar energy. Natural photosynthetic systems offer valuable inspiration, but many rely on complex pigment–protein interactions and have limited spectral coverage, which pose challenges for rational design. Chlorosome mimics, which are self-assembling pigment aggregates inspired by green photosynthetic bacteria, offer structural simplicity, flexible tunability, and strong excitonic coupling through pigment–pigment interactions. However, these pigment aggregates suffer from limited absorption in the green and near-infrared regions and, similarly to other light-harvesting systems, reduced energy transfer efficiency at high donor concentrations. One promising strategy to overcome these limitations is the integration of plasmonic nanoparticles, which enhance local electromagnetic fields, increase spectral coverage, and make new energetic pathways accessible. Although plasmonic enhancement has been widely studied in pigment–protein complexes like Photosystem I and light-harvesting complexes (LHCs), its application to pigment-pigment self-assembled systems remains largely unexplored. This perspective presents recent advances in biomimetic light-harvesting design with chlorosome mimics and explores the potential for plasmonic enhancement of photophysics in these systems. We examine the structure of chlorosomes and their artificial mimics to understand the role of pigment-pigment interactions in facilitating highly efficient energy transfer.