Researchers at the University of Cambridge have investigated the photonic properties of hydrogels embedded with microalgae and the resulting improved efficiency of algal growth within. They hope to scale up algal productivity for commercial applications and novel material synthesis.
Cambridge scientists have found that cell clusters in algal hydrogels distribute and use light better than flat layers of algae. They also improved the efficiency of algal hydrogels by adding particles that scatter light. These discoveries could help grow more microalgae for large-scale commercial purposes. The study, done in the department of chemistry, is published in the Proceedings of the National Academy of Sciences.
What Are Algal Hydrogel Biohybrids?
Microalgae are tiny, single-celled algae with many commercial uses. One challenge in using them on a large scale is growing them efficiently. Microalgae can be grown in liquids (like in bioreactors) or solid forms (like flat algae layers or hydrogels). This study focuses on hydrogels, which are networks of polymers mixed with water. Biohybrids that mix algae with hydrogels can create new materials. They can be used as sensors for chemicals, environment remediators, or even as artificial leaves. But, when microalgae grow in hydrogels, they form cell clusters because the gel confines them. This affects how light is spread and absorbed, so the researchers decided to study it using experiments and computer simulations.
Figure 1: Photograph taken from a gel pad embedded with microalgae and the closed-up microscopic views showing the individual cell aggregates and single cells within a single cluster
Better Light Distribution
The researchers measured how these cell clusters handle light by using confocal microscopy and optical coherence tomography. Then, they created and verified a computer model to simulate these properties. They discovered that cell clusters manage light better at higher cell densities than flat algae layers. This leads to better light distribution and use, and possibly faster growth.
Improving Efficiency
Seeing the potential of algal hydrogels, the researchers aimed to improve them. They found that by adding particles that scatter light, the algae harvest light better. This allows the microalgae to grow faster, even with less light.
Figure 2: Photographs taken from gel pads incorporated with scattering-enhancing cellulose microparticles (CMP) of different concentrations
Future Applications
Other than developing new materials, microalgae have many commercial uses, such as in medicine and animal feed. They can also help protect the environment by capturing carbon dioxide (CO2) and cleaning up pollution. This study shows that better light management in algal hydrogels can help up scaling microalgae for industrial uses.
The study was authored by PhD student Sing Teng Chua and research associate Dr Alyssa Smith from the Bio-inspired Photonics group in the Department of Chemistry, led by Prof Silvia Vignolini. The Bioinspired Photonics group, which conducted the study, focuses on biological structural colour. They aim to create sustainable photonic materials by studying the chemical and nanoscale properties of such systems.
Learn more about the Bioinspired Photonics Group.
Author Information
References & Links
1. Sing Teng Chua, Smith, A., Murthy, S., Murace, M., Yang, H., Lukas Schertel, Kühl, M., Pietro Cicuta, Smith, A.G., Wangpraseurt, D. and Vignolini, S. (2024). Light management by algal aggregates in living photosynthetic hydrogels. Proceedings of the National Academy of Sciences, 121(23). doi: https://doi.org/10.1073/pnas.2316206121.
2. Udayan, A., Pandey, A.K., Sharma, P., Sreekumar, N. and Kumar, S. (2021). Emerging industrial applications of microalgae: challenges and future perspectives. Systems Microbiology and Biomanufacturing. doi: https://doi.org/10.1007/s43393-021-00038-8.
Credits and Acknowledgements
This work was supported by the ERC BiTe ERC‐2020‐CoS-101001637 to S.V. S.T.C. and A.S., the Harding Distinguished Postgraduate Scholarship to S.T.C., the Biotechnology and Biological Sciences Research Council (BB/M011194/1) to A.S., EU Horizon 2020 program (H2020-MSCA-ITN-2019) grant N 860125 “BEEP” to S.V. and M.K., the Independent Research Fund Denmark (DFF-8022-00301B & DFF-8021-00308B), the Gordon and Betty Moore Foundation (grant no. GBMF9206; https://doi.org/10.37807/GBMF9206) to M.K., and the Gordon and Betty Moore Foundation (GBMF9325) to D.W., and the NSF (NSF-IntBIO, Award #2316391) to D.W. We acknowledge support from the Swiss National Foundation (Sinergia #198750).
We would like to thank the Culture Collection of Algae and Protozoa for providing the wild-type microalgae strain 137c of C. reinhardtii. We thank Dr. Richard Parker, Dr. Yu Kui, and Dr. Gianni Jacucci for the insightful discussion and constructive feedback. We also thank Dr. Karin Muller of the Cambridge Advanced Imaging Centre for her technical support and assistance in conducting the electron microscopy.