Researchers built a flexible, low-cost sensor from peepal tree leaves that detected vitamin B2 down to 0.049 micromolar and vitamin B12 down to 0.088 picomolar in laboratory tests. According to research reviewed by Gram, the device worked in spiked serum samples, though it has not been tested in people.
Researchers have built a flexible, low-cost sensor from the leaves of the peepal tree, a plant also called Ficus religiosa. The leaf serves as a natural base, and a plant-derived material called chitosan helps hold a special silver-and-magnesium-oxide mixture that carries an electrical signal. In laboratory tests, the device picked up vitamin B2 and vitamin B12 at very low levels, including amounts as small as 0.088 picomolar for B12. It also worked in serum samples to which known amounts of the vitamins had been added. According to research reviewed by Gram, these results point to a possible path toward cheaper, greener tools for checking vitamin levels. The sensor has not yet been tested in clinical studies with patients, so it is far from being a home test or a medical tool. The findings are early and come from controlled lab work.
Key Statistics
A 2026 laboratory study published in Analytical Methods found that a leaf-based electrochemical sensor could detect vitamin B2 at concentrations as low as 0.049 micromolar.
In the same 2026 laboratory study, the sensor detected vitamin B12 at concentrations as low as 0.088 picomolar, with a measurable response across a range of 1 to 100 picomolar.
The 2026 laboratory study reported that its leaf-based electrode had an active surface area of 0.2082 square centimeters, which the researchers linked to improved electrical conductivity and sensitivity.
The Quick Take
- What they studied: Can a sensor built partly from peepal tree leaves accurately measure two B vitamins, B2 and B12, in a lab setting?
- Who participated: No people took part in this study. The researchers tested their sensor in lab solutions and in serum samples, which is the clear liquid part of blood, with known amounts of vitamins added. No sample size was reported.
- Key finding: The sensor detected vitamin B2 at levels as low as 0.049 micromolar and vitamin B12 at levels as low as 0.088 picomolar. Those amounts are extremely small, which suggests the device is highly sensitive, but this result comes from lab testing only.
- What it means for you: This research does not change how you should take vitamins or check your levels. It shows that a new kind of sensor is being developed, and it may eventually lead to cheaper testing tools. For any concern about vitamin levels, talk with a doctor or pharmacist and ask about standard blood tests.
The Research Details
The researchers built a thin, flexible electrode, which is a small conductive strip that carries an electrical signal. They started with the leaf of the Ficus religiosa tree, also called the peepal tree. The leaf’s veins and surface were used as a natural framework, or scaffold, for the sensor. This made the device both plant-based and sturdy enough to handle.
Next, the team coated the leaf with chitosan, a material made from the shells of crustaceans and used in many products. Chitosan helped the leaf hold a special nanomaterial, a mixture of silver and magnesium oxide particles that are only billionths of a meter in size. These particles improved the electrical flow and increased the surface area that could react with the vitamins. The team used a range of microscopes and chemical analysis tools to confirm the materials were built as intended.
Finally, the researchers tested the sensor by placing it in solutions with different amounts of vitamins B2 and B12 and measuring the electrical signal. They also added known amounts of the vitamins to serum samples to see whether the sensor could still find them in a more complex liquid. The method is a common way to test a new sensor before any clinical use.
Testing at many concentration levels shows whether the sensor’s signal rises in a predictable way as vitamin amounts change. Adding vitamins to serum samples helps show whether the device still works in a real biological fluid, which contains many other substances that could interfere. These steps are important early checks, but they are not the same as testing in real patients.
The study was published in a peer-reviewed chemistry journal, which means outside experts reviewed it before publication. The paper describes several ways the team checked its materials and results. However, it appears to be a laboratory proof-of-concept study with no reported human participants and no reported sample size. Results from lab sensors often change when the device is used in busy clinics, with different patients, storage conditions, and operators.
What the Results Show
The main result is that the sensor responded to vitamin B2 across a range of 1 to 100 micromolar. Within that range, the signal changed in a consistent way as the amount of vitamin B2 changed. The reported detection limit, meaning the smallest amount the sensor could reliably identify, was 0.049 micromolar. The reported quantification limit, the smallest amount it could measure with reasonable accuracy, was 0.151 micromolar.
For vitamin B12, the sensor worked across two ranges. It responded to amounts from 1 to 100 picomolar, and to amounts from 100 to 1500 picomolar, with different sensitivity in each range. The reported detection limit was 0.088 picomolar, and the quantification limit was 0.157 picomolar. A picomolar is a trillionth of a mole, so these numbers describe extremely small amounts of the vitamin.
The researchers also reported that the sensor showed good selectivity, meaning it appeared to respond mainly to the target vitamins rather than to other substances tested alongside them. When vitamins were added to serum samples, the sensor was still able to pick them up. The team also described the device as stable, quick to respond, and reusable, though these claims come from short lab tests.
The electrode’s active surface area was reported as 0.2082 square centimeters. A larger active area generally gives a sensor more room to interact with the target molecules, which may help explain its sensitivity. The researchers also used microscope images to show that the silver-magnesium oxide particles were spread across the leaf-based scaffold.
The study also highlights sustainability. Because the base is a leaf and the coating is derived from natural material, the team presents the device as a possible greener alternative to some electronic sensors that rely on more energy-intensive or costly manufacturing. This is a stated goal and potential advantage, but the paper does not measure real-world cost or environmental impact in detail.
Electrochemical sensors, which detect substances by measuring electrical changes, are an active area of research for vitamins and other nutrients. Many existing methods rely on chromatography or lab-based assays, which can be accurate but are slower, costlier, and require specialized equipment. Sensors that use nanomaterials, such as metal oxide particles, have become more common because they can boost sensitivity. This study adds a plant-based flexible scaffold to that approach. Its main novelty is the use of a natural leaf structure, not a major leap in the detection method itself.
The most important limitation is that the sensor was tested in laboratory solutions and spiked serum samples, not in blood from real people with varying vitamin levels. Real blood contains many substances that could affect readings, and results can change across different people and conditions. The paper also does not clearly report the number of samples or repeated test runs, which makes it harder to judge how consistent the results are.
The study does not show how the device would perform outside a lab, how long it lasts over many uses, or whether it would cost less than existing tests in practice. Vitamin B12 detection at picomolar levels is an extremely sensitive result, but sensitivity alone does not guarantee accuracy for medical decisions. Further testing with larger, independent sample sets and clinical samples would be needed before any practical use.
The Bottom Line
Based on this single lab study, there are no changes to vitamin intake or testing that people should make. Confidence that the sensor works as described in the lab is moderate, since the reported measurements appear internally consistent. Confidence that it will work accurately in clinical or home settings is low, because it has not been tested in that way. Anyone concerned about vitamin B2 or B12 levels should continue to rely on standard medical testing and advice from a health professional.
Researchers in analytical chemistry, biosensor design, and sustainable materials may find this work useful. Public health and laboratory planners in areas where testing is expensive may also want to follow the work. People who simply want to know their vitamin status should not rely on this research yet. Those who take vitamin supplements, have a diet that may be low in B12, or have a condition that affects absorption should talk with a doctor about testing.
This research is at an early stage. Moving from a lab sensor to an approved medical device usually takes years of further testing, including clinical trials, manufacturing checks, and regulatory review. Realistically, consumers may not see a tool based on this design for many years, if it ever reaches the market.
Frequently Asked Questions
Can a leaf-based sensor test my vitamin B12 levels at home?
Not yet. The leaf-based sensor was only tested in laboratory solutions and spiked serum samples in a 2026 study. It has not been tested in patients or approved for home use, so vitamin B12 levels should still be checked with standard medical blood tests.
How sensitive is the new vitamin B12 sensor?
In laboratory tests, the sensor reported a detection limit of 0.088 picomolar for vitamin B12, which is an extremely small amount. The researchers measured responses across 1 to 100 picomolar and 100 to 1500 picomolar. This sensitivity was seen only in controlled lab conditions.
What is the peepal tree leaf used for in this sensor?
The peepal tree leaf, Ficus religiosa, serves as a natural flexible base called a scaffold. Its veins and surface were coated with chitosan and a silver-magnesium oxide mixture. This design aims to make sensors that are more sustainable and less costly to produce than some conventional options.
Which vitamins did the leaf-based sensor detect in the study?
The sensor was designed to detect vitamin B2, also called riboflavin, and vitamin B12, also called cobalamin. Both are essential micronutrients. The study reported detection limits of 0.049 micromolar for B2 and 0.088 picomolar for B12 in laboratory settings.
Want to Apply This Research?
- Track your vitamin intake from food and supplements, such as servings of fortified cereals, dairy, eggs, and any B-complex or B12 supplement, with the dose listed in micrograms or milligrams. Note the date of any blood test and the result your doctor reports for vitamin B12 or B2 if you have one.
- Use the app to set a reminder to take a supplement at the same time each day if your doctor has recommended one. Log foods rich in B vitamins, such as lean meat, fish, eggs, dairy, and fortified grains, to see patterns in your intake over a week. Share these logs with your healthcare provider at your next visit.
- Keep a monthly summary of your vitamin intake and any symptoms you notice, such as fatigue or tingling, and bring it to regular checkups. Plan for blood tests as your doctor advises rather than relying on the app to replace them. Review your logs every few months to see whether your habits are meeting the amounts your doctor has recommended.
This article summarizes a laboratory study of a prototype sensor and does not provide medical advice. The research did not involve clinical testing in patients, and the device is not approved for diagnosing or monitoring vitamin levels. Anyone with questions about vitamin B2 or B12 status, supplements, or symptoms should consult a qualified healthcare professional.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.