Description:FIELD OF THE INVENTION
The present invention relates to a user configurable smartwatch as a point-of-care testing device.

More particularly, the present invention relates to a smartwatch that is easily configurable by a user for real-time detection and monitoring a wide range of biomolecules and temperature monitoring.

BACKGROUND OF THE INVENTION
Affordable and accurate testing devices that can be used at the site of need are essential for managing communicable and non-communicable diseases. With the recent pandemic, the necessity of such testing devices has been well-understood. An ideal Point-of-Care testing (PoCT) device must meet the 'ASSURED' criteria defined by the World Health Organization- Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free and Deliverable to the end-users. The development of highly sensitive and selective electrochemical biosensors has paved the way for the rapid growth of PoCT devices.

Most electrochemical-based PoCT devices quantify the biomarker by monitoring the oxidation/reduction current of the biomarker in response to an applied potential. This is achieved by employing a potentiostat for electrochemical signal transduction and quantification. A typical potentiostat has two main functions, firstly, it is used to maintain a specified potential difference across the sensing electrode and a reference electrode for the electrochemical reaction and secondly it amplifies the resulting oxidation/reduction current from the sensing electrode obtained from the electrochemical reaction of the biomarker.

The personal glucometer is one of the most successful commercialized PoCT devices. It employs a glucose sensor strip and a corresponding meter to quantify blood glucose using the amperometry technique. But these meters are specific to their sensor electrode, which leads to separate meters being developed for different sensors. Also, testing a new biomarker will require the development of an entirely new meter. This results in a large time for device development, including the various standardizations, regulatory approvals, and market time before the device can reach the end-user.

In a pandemic like the recent COVID-19, where Time is crucial, having a device that can be configured easily as per the requirement of an electrochemical biosensor for the new biomarker will be a boon. The end-user will be able to use the same device for different biomarker detection, eliminating the requirement of separate meters for quantifying different analytes.

Also, if the detection technique is voltammetry instead of amperometry, multiple biomarkers can be quantified simultaneously. This is because, in voltammetry, a potential window is swept on the sensor electrode, enabling the quantification of multiple biomarkers that can oxidize/reduce in the given potential window. A baseline correction may be required in these situations if the diffusive current from a biomolecule affects the current response of the other biomolecules of interest. Despite numerous advantages of voltammetric techniques, most of these works on the simultaneous detection of biomolecules have not been developed into a stand-alone device. They require a personal computer or a mobile phone to interpret the results.

There is an urgent need to develop an easily configurable testing platform for multiplexed detection without compromising advantages like affordability, accuracy, and portability. Also, by miniaturizing the testing platform to fit into a wearable device like a smartwatch, the quality of healthcare management can be further enhanced. Literature in the existing state of art showcases Smartwatches capable of monitoring different physiological parameters, but there is also an increasing need for quantifying metabolites in body fluids.

Reference is made to Patent application no. WO-2017067268-A1 disclosing a smart watch capable of performing multi-parameter instant inspection and wireless transmission, comprising a watch main body and a watchband. The watch main body comprises a housing component, an instant inspection component, an operation component, a detection control component and a power supply component. The instant inspection component is provided with a test paper socket portion. The test paper socket portion is arranged inside the housing component and is provided with at least one slot which is connected to the external area of the smart watch via an opening arranged on a side wall of an upper watch cover of the housing component. The test paper socket portion is used for accommodating a test paper and generating a corresponding electric signal according to the type of the test paper inserted into the slot and sample information carried thereby. The detection control component comprises an instant inspection module electrically connected to the test paper socket portion. An instant inspection control module performs corresponding data processing on the electric signal from the test paper socket portion and obtains and stores an instant inspection result related to the sample information.

Another reference is made to Patent application no. JP-2022506925-A disclosing a device for analyzing a user's body fluid sample comprising at least one first port for receiving an electrochemical sensor structure, wherein the electrochemical sensor structure has a first set of electrodes for contacting the body fluid sample. A housing with a circuit and an identification circuit for identifying one or more biomarkers that can be analyzed using the electrochemical sensor structure. An analytical circuit comprising a set of coupling electrodes for electrical coupling to a first set of electrodes of the electrochemical sensor structure for analyzing the identified one or more biomarkers in the body fluid sample. The said in the body fluid sample to determine a set of biosensing parameters based on the identified one or more biomarkers and by controlling the analytical circuit based on the set of biosensing parameters. A control circuit coupled to the identification and analysis circuit for analyzing one or more identified biomarkers. An apparatus comprising an output unit for outputting the analysis result of the analysis of the identified one or more biomarkers in the body fluid sample.

However, the inventions in the existing state of art fail to disclose a user configurable smartwatch as a Point-of-Care testing device capable of testing and monitoring multiple biomolecules in a single platform without any change in the device hardware.

ADVANTAGES OF THE PRESENT INVENTION OVER THE EXISTING STATE OF ART:
The present invention provides a compact and highly accurate user configurable smartwatch as a point-of-care testing device for real-time detection and monitoring of biomolecules. The device is capable of electrochemical detection of vital biomolecules using amperometric and voltammetric techniques and can be configured easily using a wirelessly enabled software application for a wide range of metabolites without any change in the device hardware. The present invention provides a quick testing of new biomolecules without the need to develop a dedicated test device for all new sensors, therefore it supports easy market-entry for advancement in the existing sensors as the same device can be used by simple software updates. The present invention is capable of baseline subtraction to overcome limitations associated with certain measurements such as measurement of uric acid in the presence of ascorbic acid. The device can perform simple baseline subtractions that enable the detection of multiple biomarkers on the same sensor strip using the voltammetry technique. It provides flexibility of testing different electrochemical biosensors in the same platform providing a quick and affordable personalized healthcare assistance to the user. The device is simple to use, provides rapid results and can be operated by an individual with minimal training.

OBJECT OF THE INVENTION
In order to obviate the drawbacks in the existing state of the art, the main object of the present invention is to provide a user configurable smartwatch as a point-of-care device capable of real-time detection and monitoring of a wide range of biomolecules using strip-based electrochemical sensors.

Another object of the present invention is to provide a smartwatch capable of being configured easily using a wirelessly enabled software application for a wide range of biomolecules without any change in the device hardware.
Yet another object of the present invention is to provide a smartwatch capable of performing both amperometric and voltammetric analysis of vital biomolecules using electrochemical biosensors.

Yet another object of the present invention is to provide smartwatch with a software configurable potentiostat that allows flexibility in testing different electrochemical biosensors on the same platform.

Yet another object of the present invention is to provide a smartwatch capable of performing simple baseline subtractions for the detection of multiple biomarkers on the same sensor strip using the voltammetry technique.

Yet another object of the present invention is to provide a smartwatch capable of transferring sensor parameters from an input-output to the smartwatch through wireless technology such as BLE (Bluetooth Low Energy) technology.

Yet another object of the present invention is to provide a smartwatch capable of providing accurate and reproducible results with a low relative standard deviation in the measurement of the vital biomolecules like glucose, uric acid and ascorbic acid etc.

Yet another object of the present invention is to provide a smartwatch capable of baseline subtraction to overcome limitations associated with certain measurements such as measurement of uric acid in the presence of ascorbic acid.

Yet another object of the present invention is to provide a smartwatch capable of monitoring temperature in addition to its use as a regular watch.

SUMMARY OF THE INVENTION:
The present invention is directed to a user-configurable smartwatch that serves as a point-of-care testing device for real-time detection and monitoring of biomarkers using amperometric and voltammetric techniques which can be easily configured using a software application for a wide range of biomolecules. The smartwatch can perform both amperometric and voltammetric analysis of vital biomolecules using electrochemical biosensors. The device has a software configurable potentiostat that allows the flexibility of testing different electrochemical biosensors in the same platform, eliminating the need for dedicated meters for each sensor type i.e., the device is adaptable to any new electrochemical sensor with simple software application updates without requirement of any change in the device hardware.

The smartwatch can perform baseline subtractions that enable the detection of multiple biomarkers on the same sensor strip using the voltammetry technique and can been used to test clinically significant biomolecules like glucose, uric acid, and ascorbic acid on disposable sensor strips based on user selection from a software application. The device can overcome the limitation associated with the measurement by doing a baseline subtraction and provide accurate and reproducible results with a low relative standard deviation.

The smartwatch is promising in situations like a pandemic where the same device can be used for testing a new biomarker and can also be used for regular self-health monitoring. The software application can be simply updated to perform the testing of any new electrochemical sensor. The device can provide a quick reach of testing new biomolecules to the market without the need to develop and launch a dedicated test device for all new sensors. The user can select the new sensor from the software application, and only the sensor properties and its calibration parameters need to be updated in the cloud in the backend, and through an over-the-air update, the new sensor selection will be available to the end-user. The smartwatch can also monitor temperature in addition to its use as a regular watch.

BRIEF DESCRIPTION OF DRAWINGS
Figure 1(A) depicts the system architecture showing the interaction between different modules.
Figure 1(B) depicts the state machine of the smartwatch.
Figure 2 depicts the user interface for a software application for communication with the smartwatch. (A) Welcome, (B) Login (C) Available Bluetooth devices, and (D) Sensor selection screens.
Figure 3(A) depicts the data transfer format used to update sensor parameters from the software application to the smartwatch.
Figure 3(B) depicts the data transfer format used to update the Time information from the software application to a smartwatch.
Figure 4(A) depicts user configurable device.
Figure 4(B) Current response obtained for ascorbic acid of concentrations 125-1000 µM (A)
Figure 4(C) Current response for uric acid of concentrations 72.5-625 µM,
Figure 4(D) Current response obtained with the meter for uric acid of concentrations 125, 250, 375 μM in the presence of ascorbic acid in the concentration range of 0-500 μM.
Figure 4(E) Current response obtained with the meter for glucose of concentrations 3-27 mM.
Figure 5 depicts Bluetooth data transfer technology for the device.
Figure 6(A) Display of the regular operation of the device as watch
Figure 6(B) Display of the measured body temperature
Figure 6(C) Display of the sensor parameters received on the smartwatch via Bluetooth communication.
Figure 6(D) Display on the smartwatch before test strip insertion
Figure 6(E) Display on the screen once the strip is inserted.
Figure 6(F) Display of test result after the electrochemical measurement of the analyte

DETAILED DESCRIPTION OF THE INVENTION ILLUSTRATIONS AND EXAMPLES
While the invention has been disclosed with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from its scope.

Throughout the specification and claims, the following terms take the meanings explicitly associated herein unless the context clearly dictates otherwise. The meaning of “a”, “an”, and “the” include plural references. Additionally, a reference to the singular includes a reference to the plural unless otherwise stated or inconsistent with the disclosure herein.

The present invention provides a user-configurable smartwatch as a point-of-care testing device for real-time detection and monitoring of biomarkers using amperometric and voltammetric techniques. The device can be easily configured using a software application for a wide range of biomolecules, allowing for flexibility and adaptability to new sensor types.

The smartwatch is equipped with electrochemical biosensors and a software configurable potentiostat, which eliminates the need for dedicated meters for each sensor type. The device can perform baseline subtractions, enabling the detection of multiple biomarkers on the same sensor strip using the voltammetry technique. The smartwatch can test clinically significant biomolecules such as glucose, uric acid, and ascorbic acid on disposable sensor strips, selected by the user from the software application.

The device can also monitor temperature and can be used for regular self-health monitoring. The software application can be easily updated to perform the testing of any new electrochemical sensor, providing a quick reach of testing new biomolecules to the market without the need to develop and launch a dedicated test device for all new sensors. The smartwatch is promising in situations like a pandemic, providing a versatile and adaptable device for testing new biomarkers.

SYSTEM DESIGN:
The smartwatch comprises a microcontroller for controlling the various functions of the device, an analog-to-digital converter for digitizing a voltage output from an electrochemical measurement, a real-time clock for timekeeping, a Bluetooth module for communication with a smartphone, a memory liquid crystal display (LCD) with low power consumption for displaying the time, date, and test results, a temperature sensor for monitoring temperature during the electrochemical measurement, a potentiostat for controlling a potential and a conversion ratio for the electrochemical measurement, a rechargeable lithium-ion battery, and a low dropout regulator.

The smartwatch is configurable by a user through a software application, capable of performing amperometric or voltammetric measurement on the same device, and capable of adapting to any new electrochemical sensor with simple software application updates without requiring hardware changes. The rechargeable lithium-ion battery and low dropout regulator provide a supply voltage to the microcontroller, analog-to-digital converter, real-time clock, Bluetooth module, liquid crystal display (LCD), temperature sensor, and potentiostat.

The smartwatch is capable of performing simple baseline subtractions, enabling the detection of multiple biomolecules on the same sensor strip using the voltammetry technique. It can accurately and reproducibly test for clinically significant biomolecules such as glucose, uric acid, and ascorbic acid on disposable sensor strips. It is also able to overcome limitations associated with the measurement of uric acid in the presence of ascorbic acid through the use of baseline subtraction.

The method for point-of-care testing of biomolecules using the smartwatch involves selecting a biomolecule to be tested through a software application, configuring the smartwatch for the specific electrochemical measurement by adjusting a potential and a conversion ratio through the software application, maintaining a constant or sweeping potential between working and reference electrodes depending on the target biomolecule, converting a response current to a corresponding voltage, amplifying and filtering the voltage, and digitizing the voltage using the analog-to-digital converter. The digitized data is then processed using the microcontroller and displayed on the liquid crystal display (LCD) or transmitted to the smartphone via the Bluetooth module.

The temperature during the electrochemical measurement is also monitored using the temperature sensor and displayed on the liquid crystal display (LCD) or transmitted to the smartphone via the Bluetooth module. The software application can also be updated to perform the testing of any new electrochemical sensor. The method further comprises performing baseline subtraction to detect multiple biomolecules on the same sensor strip and maintaining a constant or sweeping potential between working and reference electrodes depending on the target biomolecule.

Fabrication and electrochemical characterization of glucose, ascorbic acid, and uric acid biosensors:
The sensor strips for electrochemical detection were developed using a semi-automated screen-printer TP-450L. The sensor strips fabricated with the base silver layer are referred to as screen-printed electrodes (SPE), and the strips without the base silver layer are referred to as screen-printed carbon electrodes (SPCE). The area of the working electrode was 3.14 mm2 (r = 1 mm). Electrochemical characterization of the sensors was done using the electrochemical workstation, CHI660C.

The electrochemical detection of UA and AA was performed on activated SPCEs. The electrode activation was carried out in 1 M H2SO4 by electrochemically cycling the potential between -0.2 to 1.8 V for 20 cycles. Cyclic voltammograms were recorded in a potential window of -0.6 to 0.6 V at a scan rate of 100 mV s-1 in 0.1 M PBS. UA solution was added into PBS so that the test solution's resultant concentration varied from 100 to 1000 µM. Similarly, the resultant concentration of AA in the test solution varied from 125 to 1250 µM.

The electrochemical sensor for glucose detection was fabricated. Briefly, CuO nanoparticles were mixed with carbon ink (33% w/w) and screen-printed on the working area of SPE and cured at 45 °C for 1 hour. This sensor for glucose detection is referred to as CuO/SPE. The electrochemical detection of glucose was carried out on CuO/SPE by amperometry in 0.1 M NaOH. Chronoamperometry was performed at a potential of 0.6 V for 25 s. Glucose solution was added to the 0.1 M NaOH such that the resultant concentration varied in the test solution in the range of 3 to 27 mM.

Design of configurable smartwatch for voltammetry and amperometry:
The ultra-low power microcontroller, PIC16LF1788, was used to control AFE, RTC, LCD, and BLE modules. The AFE LMP91000 was configured to perform either amperometry or voltammetry in addition to temperature measurements. The internal architecture of LMP91000. The communication between the potentiostat (AFE) and microcontroller was carried out using an I2C protocol. The AFE draws only 10 µA during measurements and 0.6 µA while in sleep mode, making it an ideal choice for point-of-care applications.

The system architecture showing the different modules, communications, and its interface with the controller is shown in Fig. 1A. The PIC 16LF1788 supports an Analog to Digital Converter (ADC) with 12 bit resolution. Therefore, for 3 V operations, the ADC could capture voltage with a resolution of 0.732 mV. A low-power serial RTC, M41T62 was used for timekeeping. I2C communication was used for reading the time and date information from RTC and also to update new time information to RTC. The RTC draws only 350 nA from the battery for typical timekeeping applications.

The Bluetooth Low Energy module, RN4871, was used to establish communication between the smartwatch and the smartphone. It supports USART communication, and a baud rate of 9600 was set as the transmission rate with the controller. The sharp memory LCD, LS013B4DN04 (96 * 96 pixel TFT panel) supports SPI communication, and its low power consumption of around 4 µA makes it suitable for wearable applications. A rechargeable Li-ion battery was used as the power source, and a low dropout regulator (LDO) was used to provide the required supply voltage to different modules.

The I2C compatible digital interface of AFE allows configuring the potentiostat to the required sensor characteristics by adjusting potential (cell bias) and conversion ratio (trans-impedance amplifier (TIA) gain). This is achieved by modifying the Reference Control (REFCN), TIA Control (TIACN), Mode Control (MODECN) registers in the AFE to the required sensor parameters. The suitable bias voltage, bias sign, and internal zero values are set using the REFCN register. Rload value and TIA gain are set using TIACN register. MODECN is used to select between two-electrode and three-electrode systems. The conversion ratio (TIA gain) will convert the electrochemical oxidation/reduction current to a corresponding voltage.

The state machine diagram representing the controller behaviour based on the current state, external inputs (conditions) and possible next states is shown in Fig. 1B. Once powered ON, the smartwatch will reach the 'Watch' state, where it fetches data from RTC in regular intervals and displays the time and date information on the LCD. In temperature scan intervals, the AFE can capture the temperature information, which is then displayed on the screen. This will continue until a higher priority change is detected. The priority task is when a strip insertion is detected. The system will go to 'Strip detected', 'Configuration of AFE' and 'Result calculation and display' state sequentially and remains in the last state until the inserted strip is removed. Once the strip is removed, the state comes back to 'Watch' and the normal watch and temperature measurement will be continued. The second priority task is when a successful data frame is received via the BLE module. If the received data is a sensor parameter, the corresponding sensor-related variables are updated with the received data, implying the system is ready for a different sensor. If the received data is time data, then the RTC will be updated with new time information and goes back to the state 'Watch'.

Software application design and communication data format:
For amperometric/voltammetric analysis, a constant or sweeping potential must be maintained between the working and reference electrode (VWR). This potential varies depending on the target analyte. The magnitude of the response-current also differs for different analytes. A current to voltage converter is used to convert the resulting current to a voltage which the ADC then quantifies in the controller. This conversion depends on the gain (TIAgain) of the AFE. Therefore, the ability to adjust the VWR and TIAgain must be established to make the smartwatch compatible with any sensor.

An android software application was developed using MIT App Inventor to meet this requirement. This software helps to develop the application using a model-based development framework, where the sensor list and its corresponding parameters can be defined.

Fig. 2 shows the different screens in the developed software application. Here, Fig. 2A shows the home screen/ welcome screen, and Fig. 2B shows the login screen, which immediately appears after the home screen, followed by selecting the "Connect" button to pair with the smartwatch. Fig. 2C shows available Bluetooth devices Fig. 2D shows the selection screen where the required analyte to be tested is selected from the list of available sensors.

The developed application enables the user to select the required sensor for the target analyte from a list of sensors. Once the user selects the required sensor, the application will send the sensor parameters in a predefined format to the smartwatch using Bluetooth communication. The data format for configuring the sensor is shown in Fig.3A.

Similarly, the application will also support the user to configure date and time settings using the option" Update Time" in the software application. The data format for configuring the time information is shown in Fig.3B. For both time frame/sensor data frame, the first two bytes and the last two bytes are the same. (Special characters are used to identify the start and end of the data frame). The third byte (Time/sensor) is used to distinguish the received signal as either time data or sensor data and configure the smartwatch accordingly.

In the future, if a new sensor is developed, the sensor parameters can be added to the software application. The new sensor will be incorporated into the user's software application by providing an application update. This enables over-the-air updates and configurations for the smartwatch.

Circuit design and PCB fabrication:
Electronic circuit simulations were carried out in Proteus v.8.0 and Oshon soft PIC simulator IDE. A double-sided PCB with a surface mount package of all components is designed in DipTrace PCB Layout software and fabricated using FeCl3, HCl and H2O etching method. The electronic components were soldered using a Weller SMD soldering station. MPLAB X IDE was used for programming the microcontroller using the MPLAB XC compiler. The final code was compiled and burnt into the microcontroller using PICKIT3 In-Circuit Serial Programmer.

RESULTS:
Potentiostat configuration of the smartwatch:
The smartwatch was calibrated with different known concentrations of glucose, uric acid, and ascorbic acid (as explained in Sections 2.2 and 2.3) by noting the corresponding voltage obtained from the ADC of the controller. The voltage response varies linearly with concentration from a base voltage set according to the internal zero value (here, 20% of Vcc). The calibration equation can quantify an unknown concentration from the measured voltage. The smartwatch was configured to provide constant and staircase potentials. The bit configuration of TIACN, REFCN, and MODECN registers in the AFE will be set according to the data frame received through Bluetooth communication, as shown in Fig. 3A.

The potential at which the current response must be recorded was chosen from the results obtained with the electrochemical workstation. The excitation signal of the smartwatch for voltammetry analysis was a staircase wave with a potential step of 0.06 V in the potential window of 0 to 0.6 V. The AA concentrations were calculated by using current values at 0.12 V. The detection of UA in the presence of AA requires voltammetry as the presence of AA causes a shift in the peak current of UA. Therefore, the output voltage at the potential step of 0.12 V (AA oxidation potential) was subtracted from the output voltage at 0.3 V (UA oxidation potential) to obtain the response of UA alone. This allowed the baseline correction of UA oxidation peak in the presence of AA as UA oxidizes at relatively more positive potentials. The smartwatch was also configured as a glucometer which used the amperometry technique to monitor the glucose oxidation current at a constant potential of 0.54 V.

Detection of AA and UA with staircase signal:
The detection of AA and UA was done using the voltammetric technique. Fig. 4B shows the current response obtained for known concentrations of AA using the smartwatch. A linear response was obtained with increasing concentrations of AA following the linear equation IP (µA) = 0.264C (µM) + 0.00948 with a regression coefficient, R2 = 0.993. It was seen that the results obtained using the smartwatch were in excellent conformity with the readings obtained using an electrochemical workstation. The calibration equation obtained was used to determine AA concentration in unknown samples. The reproducibility in the testing was analyzed by examining the performance of 8 different electrodes in PBS solution containing 125 μM AA. It was found that the electrodes exhibited a similar response with RSD = 7.8 % (σ = 0.0929, n=8).

The smartwatch was tested with different concentrations of UA. The current response increased linearly with increasing concentrations of UA (Fig. 4C) following the linear equation, IP (µA) = 0.0146C (µM) + 2.09 (R2 = 0.98). This calibration equation obtained was programmed to the microcontroller to determine the unknown sample concentrations of UA.

Detection of UA in the presence of AA:
One of the main attractions of the developed smartwatch is the simultaneous detection of molecules by using voltammetry. Amperometric principles cannot be used to detect biomolecules simultaneously as they cannot resolve the individual current responses obtained from multiple molecules. The capability of the device for multiplexed detection is demonstrated by the simultaneous detection of UA and AA by voltammetry. The device was tested with three different concentrations of UA (125, 250, and 375 μM) in the presence of AA in the concentration range of 0-500 μM. The baseline correction was performed to get only the diffusive current of UA. Fig. 4D shows responses obtained with the smartwatch. It is evident from the plot that the smartwatch could accurately quantify UA concentrations even in the presence of excess AA.

Table 1 analyses the variation in the current response obtained for UA in the presence of different concentrations of AA. It is seen that the RSD is less than 5% thus validating the performance of the developed smartwatch for the detection of UA in the presence of AA. The baseline subtraction employed nullifies the peak lift of UA caused due to the AA oxidation. Therefore, the analysis indicates the suitability of the smartwatch for the simultaneous detection of molecules on a single electrode using voltametric techniques.

Table. 1: Analysis of the variation in response obtained for UA in the presence of AA
UA concentration (µM) AA concentration (µM) Current (µA) RSD (%)
125 0 3.48 4.07
125 3.25
250 3.5
375 3.3
500 3.2
250 0 6.457 3.49
125 6.428
250 6.2
375 5.914
500 6.228
375 0 8.5142 3.77
125 8.94
250 8.88
375 8.51
500 8.14

Detection of glucose using amperometry technique:
The smartwatch was configured as described in Section 2.3 to perform amperometry for glucose detection. The calibration equation was deduced by noting the voltage obtained from the ADC for different known concentrations of glucose. Fig. 4E shows the corresponding current obtained with the smartwatch for different concentrations of glucose at an excitation potential of 0.54 V. The response obtained followed the linear equation, Ip (mA) = 0.0153C (mM) + 0.0673 with R2 0.9774 and was in excellent conformity with the results obtained from an electrochemical workstation. The reproducibility in testing was evaluated by analysing the current response obtained for 3 mM glucose on 10 different electrodes. It was seen that the analysis was highly reproducible with a relative standard deviation of 1.93% (σ = 1.87, n = 10). Since the device uses a 12 bit ADC, the device could measure glucose concentration with a high resolution of 0.0217 mg dL-1.

Interfacing the smartwatch with the software application:
The application was developed by MIT App Inventor for configuring the smartwatch. The model-based development of the MIT App Inventor helps to develop the android application by arranging available blocks as per the requirements. The feasibility of the watch as a configurable testing platform was demonstrated by its capability to quantify uric acid, ascorbic acid and glucose. For monitoring any new biomarker, the same smartwatch can be tuned to the new sensor strip by just selecting the sensor option that would be made available in the software application by application updates.

Fig. 5 shows the smartwatch interfaced with the smartphone for glucose detection. In future, if a new sensor is available in the market, the user will get a notification to update the application, by doing so, the user can configure his smartwatch ready for the new sensor strip. Once he selects the needed sensor, the embedded sensor parameter will be transferred to the smartwatch in the specified format and once the watch receives the data, the data is checked for its correctness. Once this check is passed successfully, the watch will update to the selected sensor parameters. Also, the user can update the time and date information on the watch by choosing the option 'Update Time'. This will fetch the current Time and date knowledge from the smartphone and send it via Bluetooth in a defined format to the watch. If the data passes the correctness check, the new Time and date will be updated to the Real Time Clock (RTC). Thereby the watch will start showing the updated Time.

The electrochemical testing of biomolecules on disposable sensor strips using the smartwatch is shown in Fig. 6 (A-F). When a strip is detected, the AFE is configured according to the selected sensor for electrochemical detection. The analyte concentration is displayed on the liquid crystal display (LCD) after the measurement. The experiments proved the ability of the developed smartwatch to perform voltammetry and amperometry based on sensor requirements. The smartwatch is compact having a dimension of 30 mm x 40 mm and can be used as a regular watch as well as a personalized wearable gadget. It can be configured for different sensor strips by choosing a specific sensor out of the different sensor options available in an android application on a smartphone. Therefore, multiple health biomarkers can be monitored with the same device thus eliminating the need for carrying dedicated meters for different analytes. Also, at regular intervals of Time, the smartwatch is able to capture the body temperature of the user. This easily configurable electronic smartwatch paves a new path in point-of-care testing by simplifying electrochemical detection of biomarkers.
, Claims:1. A user configurable smartwatch as a point-of-care testing device for testing of biomolecules, the smartwatch comprising:
﹣ microcontroller for controlling the various functions of the smartwatch;
﹣ disposable biosensor strips for testing biomolecules;
﹣ analog-to-digital converter for digitizing a voltage output from an electrochemical measurement;
﹣ Input/Output device comprising of a software application installed on said I/O device;
﹣ wireless communication module for communication with said I/O device;
﹣ temperature sensor for monitoring temperature during the electrochemical measurement;
﹣ potentiostat for testing different electrochemical biosensors;
﹣ Real-Time Clock (RTC) for displaying time, date and time-stamping test results;
﹣ rechargeable battery; and
﹣ low dropout regulator
﹣ a memory liquid crystal display (LCD) with low power consumption
wherein said smart watch is
o capable of real-time detection and monitoring of wide range of biomolecules;
o capable of performing amperometric or voltammetric analysis of said biomolecules on the same device;
o configured to any new electrochemical sensor with simple updates of said software application without requiring hardware changes in the device;
o capable of performing simple baseline subtractions enabling the detection of multiple biomarkers on the same sensor strip using said voltammetry analysis;
o capable of monitoring temperature in addition to its use as a regular watch.

2. The smartwatch as claimed in claim 1, wherein said potentiostat is capable of adjusting the potential and conversion ratio to the required sensor characteristics.

3. The smartwatch as claimed in claim 1, wherein said wireless communication module is BLE (Bluetooth Low Energy) module.

4. The smartwatch as claimed in claim 3, wherein the sensor parameters are transferred from said I/O device to the smartwatch through said BLE (Bluetooth Low Energy) module.

5. The smartwatch as claimed in claim 1, wherein said rechargeable battery and low dropout regulator provide a supply voltage to the microcontroller, analog-to-digital converter, real-time clock, Bluetooth module, liquid crystal display (LCD), temperature sensor, and potentiostat.

6. The smartwatch as claimed in claim 1, wherein the smartwatch provides accurate and reproducible results in the measurement of the clinically significant vital biomolecules with a low relative standard deviation.

7. The smartwatch as claimed in claim 1, wherein the smartwatch is capable of overcoming the limitations associated with the measurement through said baseline subtraction.

8. A method for point-of-care testing of biomolecules using the smartwatch as claimed in claim 1, the method comprising the steps of:
﹣ selecting a sensor from a software application;
﹣ selecting a biomolecule to be tested through said software application;
﹣ configuring the smartwatch for the specific electrochemical measurement by adjusting a potential and a conversion ratio through said software application;
﹣ updating the sensor properties and calibration parameters through a remote server such as cloud backend;
﹣ transferring the updated sensor selection to the smartwatch through an over-the-air update;
﹣ maintaining a constant or sweeping potential between working and reference electrodes depending on the target biomolecule;
﹣ converting a response current to a corresponding voltage, amplifying and filtering the voltage, and digitizing the voltage using the analog-to-digital converter;
﹣ monitoring temperature during the electrochemical measurement using the temperature sensor;
﹣ processing the digitized data using the microcontroller;
﹣ transmitting the data to the I/O device via the Bluetooth module;

wherein
﹣ said software application is updated to perform the testing of any new biomolecule using electrochemical sensor;
﹣ said device performs simple baseline subtractions to enable the detection of multiple biomolecules on the same sensor strip using the voltammetry technique.