Biosensor for monitoring plant health

Abstract

A biosensor (10) for monitoring the health status of plants is described, comprising: a disposable screen-printed sensor (11); a measuring cell (12) configured to contain a leaf sample in contact with the screen-printed sensor (11); a light source (14) configured to illuminate the leaf sample in the measuring cell (12); a reader configured to measure a current generated by the screen-printed sensor (11) in response to illumination of the leaf sample; means for correlating the measured current with a chlorophyll content of the leaf sample, thereby determining an index of the health status of the plant; a method for monitoring the health status of a plant using said biosensor (10) is also described.

Description

[0001] BIOSENSOR FOR MONITORING PLANT HEALTH

[0002] The present invention relates to a biosensor for monitoring the health status of plants, capable of providing information on the real and instantaneous health status of a plant .

[0003] Plant health monitoring devices are known that include sensors for monitoring environmental parameters related to plant health, such as soil moisture, temperature, illumination and CO2 concentration .

[0004] While these devices provide useful information about growing conditions, they cannot directly measure the physiological and metabolic state of the plant itself .

[0005] Other approaches involve the chemical analysis of specific metabolites present in plant tissues . However, these techniques often require invasive sampling procedures and complex laboratory analyses, making them impractical for real-time monitoring .

[0006] Photosynthesis, as the fundamental biochemicalprocess underlying plant life, represents an ideal indicator of their overall health. However, currently available methods for measuring photosynthetic efficiency, such as chlorophyll fluorescence techniques, require sophisticated and expensive instrumentation, limiting their large-scale applicability. Furthermore, they may fail to detect early signs of stress or disease, when corrective actions could be more effective .

[0007] Obj ect of the present invention is solving the aforementioned prior art problems by providing a biosensor and a method for monitoring plant health that provide a standardized and easily repeatable procedure for assessing plant health, allowing for regular and non-invasive monitoring. The ability to obtain rapid and obj ective results allows for early identification of any plant stress or disease, facilitating timely intervention.

[0008] The above and other obj ects and advantages of the invention, as will become apparent from the following description, are achieved with a biosensor and a method for monitoring the health of plants as described in the independent claims . Preferred embodiments and non-trivial variations of the present invention are the subj ect matter of thedependent claims .

[0009] It is understood that all attached claims form an integral part of this description.

[0010] It will be immediately obvious that countless variations and modifications can be made to what is described ( for example relating to shape, dimensions, arrangements and parts with equivalent functionality) without departing from the scope of the invention as appears from the appended claims .

[0011] The present invention will be better described by a preferred embodiment, provided by way of example and not by way of limitation, with reference to the attached drawings, in which:

[0012] Figure 1 shows schematic views of the biosensor for monitoring the health status of plants according to the present invention .

[0013] With reference to Figure 1, a preferred embodiment is described of a biosensor 10 for monitoring the health status of plants according to the present invention, which comprises a disposable silk-screen sensor 11, a measuring cell 12, preferably comprising an upper part 12A and a lower part 12B connected to each other by fastening means 18, for example screws, a light source, preferablyan illumination LED 14, for example connected to a cover 15 inserted into a seat 16 made in the upper part 12A, and a reader . The silk-screen sensor 11 and the measuring cell 12, appropriately designed, constitute the heart of the device; preferably, the silk-screen sensor 11 is inserted into a housing 19 made in the lower part 12B of the measuring cell 12. Preferably, the upper part 12A of the measuring cell 12 comprises a protrusion 20 configured to fit into the housing 19, secured by an 0-ring 21. To perform a measurement, a suitably treated leaf sample is inserted into the measuring cell 12, preferably into the housing 19, in contact with the sensor 11. The cell 12 contains the LED 14, preferably inserted into the seat 16 obtained in the upper part 12A above the screen-printed sensor 11, which reproduces the portion of solar illumination effective for photosynthesis . The signal produced is then captured by the sensor 11 and, via the reader, converted into a measurable current . This current can therefore be correlated, through cross-checking with the chlorophyll contained in the leaf material examined, with the health of the plant .

[0014] The biosensor 10 for monitoring plant healthaccording to the invention is based on the evaluation of the activity of the Photosystem II (PSII ) complex, a key component of the photosynthetic process . PSII activity, in correlation with chlorophyll concentration in leaves, can be correlated with the efficiency of plant metabolism and, therefore, with the health of the plant .

[0015] The disposable screen sensor 11 is configured to detect specific biochemical signals associated with the activity of the Photosystem II complex; preferably, the disposable screen sensor 11 is configured to detect the photosynthetic signal emitted by the leaf sample, which is correlated with the activity of the Photosystem II complex .

[0016] This sensor 11 can be made with various materials and printing techniques, depending on the specific needs of the application. The sensor 11 can be designed to be removable, allowing it to be swapped out to perform measurements on different samples without the need to clean or sterilize the device between samples .

[0017] Preferably, the measuring cell 12 is configured to contain and position the leaf sample and to facilitate contact between the sample and thesensor . The measuring cell 12 may include various components and mechanisms to facilitate insertion and removal of the sample, such as the protrusion 20 configured to fit into the housing 19, as well as to ensure uniform and constant contact between the sample and the sensor 11 during the measurement .

[0018] In some cases, the measuring cell 12, particularly the housing 19, can be designed to hold a specific amount of leaf sample . This amount can be determined based on the specific needs of the application and the characteristics of the screen-printing sensor . For example, the measuring cell 12 can be designed to hold a sufficient amount of leaf sample to completely cover the surface of the sensor 11, but without overloading the sensor 11 or preventing the transmission of the photosynthetic signal .

[0019] In some aspects, the measuring cell 12 may be designed to position the leaf sample in a specific position relative to the silkscreen sensor 11 and the illumination LED 14. This position may be determined based on the characteristics of the sensor 11 and the LED 14, as well as the optical properties of the leaf sample . For example, themeasuring cell 12 may be designed to position the leaf sample so that the photosynthetic signal emitted by the sample is directed toward the sensor 11 and the light emitted by the LED 14 is directed toward the sample .

[0020] The measuring cell 12 can be made of various materials, depending on the specific needs of the application. For example, the measuring cell 12 can be made of an opaque material to limit the interference of external ambient light on the measurement .

[0021] The illumination LED 14 is configured to emit light in a specific wavelength range, corresponding to the portion or portions of the solar spectrum effective for photosynthesis . This characteristic of LED 14 is essential for stimulating the photosynthetic activity of the leaf sample and, therefore, for generating the photosynthetic signal that will be detected by the screen-printing sensor 11 .

[0022] In some cases, the illumination LED 14 may be designed to emit light in more than one wavelength range .

[0023] For example, the LED 14 can be designed to emit light in a wavelength range that stimulates theactivity of the Photosystem II complex . In this way, the biosensor 10 can provide a more complete and detailed measurement of plant health.

[0024] The reader is preferably configured to convert the signal detected by the screen-printing sensor 11 into a measurable current using electronic components and circuitry. For example, the reader may include an analog-to-digital converter to convert the analog signal detected by the sensor into a digital signal that can be processed by a computer or other data processing device . The reader is also synchronized with the LED 14 and regulates its operation; at the time of measurement, the reader activates the LED 14 and simultaneously applies a potential to the sensor 11 so as to capture the photosynthetic signal thus generated .

[0025] In some aspects, the biosensor 10 includes means for correlating the measurable current generated by the reader with the activity of the Photosystem II complex and, therefore, with the health status of the plant; preferably, the means for correlating the measured current with the chlorophyll content of the leaf sample comprises a processor configured to determine the index of theplant health status by comparing the measured current and the chlorophyll content with predetermined threshold values . This correlation can be established by cross-checking with the chlorophyll content of the leaf material examined. In this way, the biosensor can provide an obj ective and quantitative measure of the plant health status, overcoming the limitations of traditional monitoring methods based on external parameters or complex chemical analyses .

[0026] To prepare the leaf sample for measurement, the leaf material can preferably be homogenized in a mortar and added to an appropriate buffer . This sample preparation process can facilitate contact between the sample and the screen-printing sensor 11, thus improving measurement accuracy.

[0027] In one embodiment of the invention, the reader can be designed to provide visual or audible output indicating the plant health status . For example, the reader can include a display to show the measurable current value or a plant health indicator . In this way, the user can easily and quickly determine the plant health status without the need for further analysis or interpretation.

[0028] Specifically, the biosensor 10 correlatesphotosynthetic efficiency with chlorophyll concentration to determine plant health. This correlation is based on measuring the current generated by the screen-printed sensor 11 in response to the photosynthetic signal emitted by the leaf sample . The measured current is then correlated with the chlorophyll concentration in the examined leaf material, thus providing a quantitative index of the plant health.

[0029] In some cases, the output from the data processing device can be displayed on a screen or transmitted to another device for further analysis or action. For example, the output can be displayed on a reader screen, sent to a computer or mobile device via a wired or wireless connection, or saved to memory for later analysis .

[0030] In some cases, the biosensor 10 can be designed to take continuous or periodic measurements, thus allowing the plant health to be monitored over time and any changes or trends to be detected. This can be particularly useful in applications such as precision agriculture, greenhouse management, botanical research, and other applications where monitoring and optimizing plant health is important .To use the biosensor 10 for plant health monitoring according to the invention, it is necessary to take a sample of leaf material from the plant to be monitored. This sample may vary in size, depending on the specific needs of the application and the characteristics of the screen-printed sensor . In some cases, the sample may be homogenized in a mortar and added to an appropriate buffer . This sample preparation process can facilitate contact between the sample and the screen-printed sensor, thus improving measurement accuracy .

[0031] Once prepared, the leaf sample is inserted into the measuring cell 12 of the biosensor 10. In some aspects, the measuring cell 12 may be designed to contain and position the leaf sample so as to optimize contact with the screen sensor .

[0032] Once the sample is inserted into the measuring cell 12, the illumination LED 14 is activated to stimulate the photosynthetic activity of the leaf sample and, therefore, to generate the photosynthetic signal that will be detected by the screen-printing sensor .

[0033] The photosynthetic signal generated by the leaf sample is then detected by the screen sensor 11 andconverted into a current measurable by the reader . Preferably, the screen sensor 11 comprises a working electrode modified with a photosynthetic protein complex, specifically Photosystem II . The measurable current generated by the reader correlates with the activity of the Photosystem II complex and, therefore, with the health of the plant . This correlation can be established by cross-checking with the chlorophyll content of the leaf material examined.

[0034] The biosensor 10 requires only a few pL of sample, such as between 10 pL and 100 pL, and provides a response within minutes, making it suitable for in situ analysis . The biosensor 10 can be used to periodically monitor a plant health, allowing for early detection of stress or disease conditions and timely corrective action.

[0035] The biosensor 10 for monitoring plant health according to the invention offers significant advantages over known monitoring methods . First, the biosensor 10 provides a direct and quantitative measurement of the plant physiological and metabolic status, based on the efficiency of its photosynthetic process . This overcomes the limitations of known methods that rely on themeasurement of numerous or external parameters or complex chemical analyses, which can be imprecise, expensive, and time-consuming.

[0036] Furthermore, the biosensor 10 is designed to be easy to use and suitable for real-time monitoring.

[0037] Furthermore, the biosensor 10 can detect stress or disease conditions early, facilitating timely interventions .

[0038] Finally, the biosensor 10 is designed to be moderately cost-effective and low maintenance .

[0039] In conclusion, the biosensor 10 for plant health monitoring according to the invention offers an advanced, precise and cost-effective monitoring method that overcomes the limitations of known methods and sensors .

Claims

CLAIMSBiosensor ( 10 ) for monitoring the health status of plants , comprising :a disposable screen-printing sensor ( 11 ) ;a measuring cell ( 12 ) configured to contain a leaf sample in contact with the screen-printing sensor ( 11 ) ;a light source ( 14 ) configured to illuminate the leaf sample in the measuring cell ( 12 ) ;a reader configured to measure a current generated by the screen sensor ( 11 ) in response to illumination of the leaf sample ;means to correlate the measured current with the chlorophyll content of the leaf sample , thus determining an index of the health status of the plant .2 . Biosensor ( 10 ) according to claim 1 , characteri zed in that the light source ( 14 ) comprises a LED configured to emit light in a wavelength ef fective for the photosynthetic process .3 . Biosensor ( 10 ) according to any of the preceding claims , characteri zed in that the screen-printed sensor ( 11 ) comprises a working electrode modi fied with a photosynthetic protein complex .Biosensor ( 10) according to claim 3, characterized in that the photosynthetic protein complex comprises Photosystem II .

5. Biosensor ( 10) according to any of the preceding claims, characterized in that the measuring cell ( 12 ) is configured to contain a leaf sample volume between 10 pL and 100 pL .

6. Biosensor ( 10) according to any of the preceding claims, characterized in that the reader comprises an analogue-to-digital converter for converting the analogue signal detected by the screen-printing sensor ( 11 ) into a digital signal, and characterized in that the reader is also synchronized with the light source ( 14 ) and regulates its operation.

7. Biosensor ( 10) according to any of the preceding claims, characterized in that it further comprises a display configured to display the plant health index .

8. Biosensor ( 10) according to any of the preceding claims, characterized in that the means for correlating the measured current with a chlorophyll content of the leaf sample comprise a processor configured to determine the index of the health state of the plant by comparing the measuredcurrent and the chlorophyll content with predetermined threshold values .

9. Method for monitoring the health status of a plant using the biosensor ( 10) according to any of the preceding claims, comprising the steps of :taking a leaf sample from the plant; inserting the leaf sample into the measuring cell ( 12 ) in contact with the screen-printing sensor ( 11 ) ;illuminating the leaf sample with the light source ( 14 ) ;measuring, by means of the reader, a current generated by the silkscreen sensor ( 11 ) in response to the illumination of the leaf sample; and determining an index of the plant health based on the measured current .

10. Method according to claim 9, characterized in that it further comprises the step of correlating the measured current with a chlorophyll content of the leaf sample to determine the plant health index .

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