Here are five key ways that nanotechnology is revolutionizing photosynthesis, creating new opportunities for a climate-resilient future and bridging the gap between biological and technological solutions.
Stress Mitigation
As climate change progresses, plants face a wide range of abiotic stresses, including salinity, drought, heat and cold stress, heavy metal stress, UV-B stress and submergence, all of which have serious impacts on a plant’s energy production system. Nanoparticles (NPs) can improve photosynthetic indices across multiple stress conditions.
For example, nanotechnology can be used to modulate a plant’s stress response at the cellular level. NPs with antioxidant properties can scavenge reactive oxygen species (ROS) produced under stress conditions, protecting photosynthetic machinery from oxidative damage. Research into this is ongoing, but one study showed promising results by adding a chloroplast-targeting peptide coating to nanomaterials. This improved the delivery of cadmium sulfide NPs, which act as light-harvesting systems, mimicking natural photosynthesis.
Stress mitigation via gene regulation is another emerging area of nanotechnology. Fluorescent carbon dots (CDs) can enhance photosynthesis by influencing the expression of specific genes — PsbP and PsiK. Research has found that overexpressing these genes can protect plants from damage caused by UV-B stress, known as photoinhibition.
Targeted Delivery of Nutrients and Water
As climate change continues to strain resources such as water and fertilizers, targeted delivery via nanotechnology can ensure they’re used efficiently, delivering them directly to where they are needed within the plant.
By using guided peptide recognition motifs, researchers circumvented plant cell barriers to biochemical delivery, enabling a 78.8% efficiency rate in delivery packages to chloroplasts.
However, the exact mechanisms of NP entry into chloroplast envelopes are still not fully understood. Research is ongoing to discover a universal delivery cassette that will efficiently deliver biomolecules to chloroplasts across diverse plant species.
CO2 Fixation
In plants, chlorophyll converts sunlight into chemical energy for glucose. This is the second stage of photosynthesis, following light capture, and it occurs via a series of chemical reactions known as the Calvin Cycle. However, this process is often limited by the availability of CO2 and the efficiency of the enzyme RuBisCO.
Nanotechnology offers a way to overcome these limitations by delivering CO2 directly to the site of fixation within plant chloroplasts, essentially turbocharging the Calvin Cycle. This targeted approach can significantly enhance photosynthetic efficiency and carbon sequestration. In a recent project, researchers developed polyethyleneimine-based NPs for enhancing the carboxylation reaction, which showed promising results without any toxic effects on the plant.
Light Harvesting
Just as homeowners with solar panels rely on batteries to store excess solar energy for later use, plants convert light energy into sugars and starches, their long-term energy storage molecules. By enhancing light-harvesting efficiency, nanotechnology can help plants produce more of these energy-rich compounds, making them more resilient and productive.
Nano light conversion agents (LCAs), such as quantum dots and rare-earth doped plasmonic NPs, can be engineered to absorb specific wavelengths of light more efficiently than natural pigments. These nano-antennas can then transfer energy to the reaction centers in plants, boosting overall light capture, particularly in shaded or suboptimal light conditions.
A recent review found that LCAs offer huge potential but that significant challenges remain. These include the production costs and sale prices of LCAs, as well as concerns over whether this so-called “light fertilizer” technology may have toxic impacts on plants or humans.
Biomass-derived CDs synthesized from rice straw, weed, leaves and cyanobacterial cells can act as both light converters and photosynthesizers. A study found that plants treated with these CDs exhibited increased photosynthetic efficiency. Furthermore, the use of biomass waste to synthesize the CDs presents a sustainable and economical closed-loop process. Preliminary results showed that 1 gram of fresh biomass yields approximately 10 milligrams of CDs, with potential for industrial-scale production.
Water Management
Water scarcity and drought are major constraints on photosynthesis, limiting plants' ability to produce food and grow. This can have significant consequences for plant survival, crop yields and overall ecosystem health.
When water is scarce, plants seek to prevent water loss by closing stomata. However, this leads to lower CO2 intake, slowing down the entire photosynthetic process. Water is directly involved in the light-dependent reactions that form the early stages of photosynthesis, so scarcity causes overall energy production to become less efficient. Under water stress, photorespiration leads to an over-production of ROS, which can lead to DNA damage. This then makes it harder for the plant to produce sugars even if water becomes available again.
However, a systematic review paper found that metal-based NPs help plants cope with drought by improving water and nutrient uptake and utilization. Cell wall alteration and stomatal closure regulation enhance water retention. Multiple studies found that rates of photosynthesis improved when these NPs were utilized.
Climate change is introducing multiple stressors that negatively impact photosynthetic efficiency. From elevated temperatures that can damage enzymes to water scarcity that limits CO2 uptake, a changing world is leaving plants struggling to survive. Future food security depends on technological advances that can mitigate these stress factors in plants — and nanotechnology offers a promising suite of tools to address these challenges at the molecular level.
