Green Science Alliance Developed Quantum Dot Type Pesticides from Organic Waste (Waste Tea Leaves, Waste Coffee Beans, Waste Woods)

KAWANISHI-CITY, Japan, Nov. 7, 2025 /PRNewswire/ -- Green Science Alliance is the Green Tech Startup company that develops cutting-edge materials and technologies for a sustainable, carbon-neutral society in energy and environmentally friendly fields. One of their cutting-edge products is called quantum dots.

Quantum dots are extremely tiny man-made nanoparticles typically between 10 and 10,000 atoms or molecules (1 to 9 nanometers) in diameter, which is smaller than 1/10,000th the width of a human hair.  They are sometimes called artificial atoms or molecules.  However, the effects of this super small size cannot be ignored, and it is their size that gives them unique abilities, including converting light to nearly any color in the visible spectrum with very high efficiency.  At this size range, the energy levels of electrons are no longer continuous and are separated due to the physical phenomenon known as the quantum confinement effect. The electronic characteristics of quantum dots are determined by the quantum confinement effect, depending on their chemical composition, size, shape, so that the wavelength of emission light depends on those characteristics.  The unique properties of quantum dots can be utilized for solar cells, displays, bioimaging, photonic crystals, lasers, LEDs, artificial photosynthesis, and quantum-dot computers.

Green Science Alliance has been researching and developing various types of quantum dots and quantum dot-based products, and this time, Dr. Ryohei Mori has successfully synthesized quantum-dot-type pesticides from organic waste (Waste Tea Leaves, Waste Coffee Beans, Waste Woods). 

In general, pesticides are classified into insecticides, fungicides, herbicides, repellents, etc.
Among pesticides, antimicrobial and fungicides are especially important because microorganisms such as bacteria, viruses, and filamentous fungi are the main cause of agricultural disease in crops. 

Typical diseases caused by bacteria are soft rot, bacterial wilt disease, bacterial canker, etc. Spotted wilt and mosaic disease are typical diseases caused by viruses. Powdery mildew and gray mold are typical diseases caused by filamentous fungi.  As such, there are various types of diseases in the agricultural crops industry although it is said that 75% of agricultural diseases in Japan are caused by filamentous fungi, followed by viruses, bacteria, and phytoplasmas. 

Therefore, Dr. Ryohei Mori has examined the effect of quantum dot-based pesticides on 3 types of filamentous fungi and those are Phytophthora infestans (tomato as host), Rhizoctonia solani (cause of rice sheath blight), and Botrytis cinerea (cause of gray mold).  As a result, even though there is concentration dependence in quantum dot-based pesticides, quantum dots synthesized from waste tea leaves, coffee bean waste and waste woods exhibited a pesticidal effect.

These types of biomass- and organic-material-based quantum dots are regarded as carbon quantum dots, and these pesticides can be regarded as carbon quantum dots type pesticides. Compared to conventional anti-bacterial materials, nano-materials such as quantum dots have a tendency to adhere to the bacterial (fungal) surface more strongly than those of commercial anti-bacterial materials. Quantum dots may interact or permeate into bacterial (fungal) cell membrane or cell wall more strongly because the size of nano-materials could be so small as a few nanometers. In addition, due to the existence of surface chemical groups on quantum dots, they attach to the bacteria (fungi) surface more strongly. After quantum dots penetrate the bacterial or fungal cell, they will influence their genes or cause active oxygen species so that bacteria (fungi) will be destroyed. Some studies also explained that carbon quantum dots may inhibit enzyme activity in bacteria to suppress peptidoglycan production, which eventually destroys bacteria. 

Moreover, because plant ingredients such as flavonoids, polyphenols, alkaloids, catechins, terpenoids, and saponins have anti-microbial effect, quantum dot-based pesticides also possess the same characteristics because these quantum dots are made from plant-based materials such as tea leaves, coffee beans, woods.

In addition, when they are applied at an agricultural field, excited electrons, excitons, and active oxygen species are generated which have anti-microbial properties because quantum dots are reported to exhibit a photocatalytic effect under the sunlight illumination.

Moreover, because these quantum dots are made from natural organic substances such as tea leaves, coffee beans, and waste woods, they are economically and environmentally friendly compared to chemically synthesized, potentially toxic, commercial pesticides.

Therefore, carbon quantum dots made from organic waste could be an innovative type of environmentally and economically friendly pesticide.

Media Contact:
Ryohei Mori
81-727598501
[email protected] 

SOURCE Green Science Alliance Co., Ltd.