Researchers at Karolinska Institutet in Sweden have developed a tiny sensor for detecting pesticides on fruit in just a few minutes. The technique, described as a proof-of-concept in a paper in the journal Advanced Science (“SERS Hotspot Engineering by Aerosol Self-Assembly of Plasmonic Ag Nanoaggregates with Tunable Interparticle Distance”), uses flame-sprayed nanoparticles made from silver to increase the signal of chemicals. While still at an early stage, the researchers hope these nano-sensors could help uncover food pesticides before consumption. | |
“Reports show that up to half of all fruits sold in the EU contain pesticide residues that in larger quantities have been linked to human health problems,” says Georgios Sotiriou, principal researcher at the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, and the study’s corresponding author. “However, current techniques for detecting pesticides on single products before consumption are restricted in practice by the high cost and cumbersome manufacturing of its sensors. To overcome this, we developed inexpensive and reproducible nano-sensors that could be used to monitor traces of fruit pesticides at, for example, the store.” |
The new nano-sensors employ a 1970s discovery known as surface-enhanced Raman scattering, or SERS, a powerful sensing technique that can increase the diagnostic signals of biomolecules on metal surfaces by more than 1 million times. The technology has been used in several research fields, including chemical and environmental analysis as well as to detect biomarkers for various diseases. However, high production costs and limited batch-to-batch reproducibility have so far hindered widespread application in food safety diagnostics. | |
Flame spray technology |
|
In the current study, the researchers created a SERS nano-sensor by using flame spray – a well-established and cost-effective technique for depositing metallic coating – to deliver small droplets of silver nanoparticles onto a glass surface. | |
“The flame spray can be used to quickly produce uniform SERS films across large areas, removing one of the key barriers to scalability,” says Haipeng Li, a postdoctoral researcher in Sotiriou’s lab and the study’s first author. | |
The researchers then finetuned the distance between the individual silver nanoparticles to enhance their sensitivity. To test their substance-detecting ability, they applied a thin layer of tracer dye on top of the sensors and used a spectrometer to uncover their molecular fingerprints. The sensors reliably and uniformly detected the molecular signals and their performance remained intact when tested again after 2,5 months, which underscores their shelf life potential and feasibility for large-scale production, according to the researchers. | |
Detected pesticides on apples |
|
To test the sensors’ practical application, the researchers calibrated them to detect low concentrations of parathion-ethyl, a toxic agricultural insecticide that is banned or restricted in most countries. A small amount of parathion-ethyl was placed on part of an apple. The residues were later collected with a cotton swab that was immersed in a solution to dissolve the pesticide molecules. The solution was dropped on the sensor, which confirmed the presence of pesticides. | |
“Our sensors can detect pesticide residues on apple surfaces in a short time of five minutes without destroying the fruit,” Haipeng Li says. “While they need to be validated in larger studies, we offer a proof-of-concept practical application for food safety testing at scale before consumption.” | |
Next, the researchers want to explore if the nano-sensors can be applied to other areas such as discovering biomarkers for specific diseases at the point-of-care in resource-limited settings. |

News
Polaritons open up a new lane on the semiconductor highway
On the highway of heat transfer, thermal energy is moved by way of quantum particles called phonons. But at the nanoscale of today's most cutting-edge semiconductors, those phonons don't remove enough heat. That's why [...]
EU seeks agreement on world’s first AI law
The European Union will seek to thrash out an agreement on sweeping rules to regulate artificial intelligence on Wednesday, following months of difficult negotiations in particular on how to monitor generative AI applications like [...]
Lightning sparks scientists’ design of ultraviolet-C device for food sanitization
Scientists at the University of Illinois Urbana-Champaign have developed a portable, self-powered ultraviolet-C device called the Tribo-sanitizer that can inactivate two of the bacteria responsible for many foodborne illnesses and deaths. The Tribo-sanitizer's UVC [...]
3D Eye Scans Emerge as a Crucial Tool in Combating Kidney Disease
A new study indicates that 3D retinal scans could revolutionize the early detection and monitoring of kidney disease, offering a non-invasive and efficient diagnostic tool. 3D eye scans can reveal vital clues about kidney [...]
Researchers develop a blood test to identify individuals at risk of developing Parkinson’s disease
Research carried out at Oxford's Nuffield Department of Clinical Neurosciences has led to the development of a new blood-based test to identify the pathology that triggers Parkinson's disease before the main symptoms occur. This [...]
“Challenging the Paradigm” – Scientists Develop New Approach To Stop Cancer Growth
Biochemists at Case Western Reserve are concentrating on the degradation of a key protein that drives cancer; represents a major shift in research. Biochemical researchers at Case Western Reserve University have discovered a a new function [...]
Researcher develops a chatbot with an expertise in nanomaterials
A researcher has just finished writing a scientific paper. She knows her work could benefit from another perspective. Did she overlook something? Or perhaps there's an application of her research she hadn't thought of. [...]
Research shows human behavior guided by fast changes in dopamine levels
What happens in the human brain when we learn from positive and negative experiences? To help answer that question and better understand decision-making and human behavior, scientists are studying dopamine. Dopamine is a neurotransmitter [...]
Tiny robots made from human cells heal damaged tissue
The ‘anthrobots’ were able to repair a scratch in a layer of neurons in the lab. Scientists have developed tiny robots made of human cells that are able to repair damaged neural tissue1. The [...]
Antimicrobial Resistance – A Global Concern
Key facts Antimicrobial resistance (AMR) is one of the top global public health and development threats. It is estimated that bacterial AMR was directly responsible for 1.27 million global deaths in 2019 and contributed to [...]
Advancing Pancreatic Cancer Treatment with Nanoparticle-Based Chemotherapy
Pancreatic cancer, a particularly lethal form of cancer and the fourth leading cause of cancer-related deaths in the western world, often remains undiagnosed until its advanced stages due to a lack of early symptoms. [...]
The ‘jigglings and wigglings of atoms’ reveal key aspects of COVID-19 virulence evolution
Richard Feynman famously stated, "Everything that living things do can be understood in terms of the jigglings and wigglings of atoms." This week, Nature Nanotechnology features a study that sheds new light on the evolution of the coronavirus [...]
AI system self-organizes to develop features of brains of complex organisms
Cambridge scientists have shown that placing physical constraints on an artificially-intelligent system—in much the same way that the human brain has to develop and operate within physical and biological constraints—allows it to develop features [...]
How Blind People Recognize Faces via Sound
Summary: A new study reveals that people who are blind can recognize faces using auditory patterns processed by the fusiform face area, a brain region crucial for face processing in sighted individuals. The study employed [...]
Treating tumors with engineered dendritic cells
Cancer biologists at EPFL, UNIGE, and the German Cancer Research Center (Heidelberg) have developed a novel immunotherapy that does not require knowledge of a tumor's antigenic makeup. The new results may pave the way [...]
Networking nano-biosensors for wireless communication in the blood
Biological computing machines, such as micro and nano-implants that can collect important information inside the human body, are transforming medicine. Yet, networking them for communication has proven challenging. Now, a global team, including EPFL [...]