1. Introduction
The Internet of Medical Things (IoMT) is revolutionizing the healthcare landscape by integrating smart medical devices, cloud computing, and real-time data analytics to enhance patient care and diagnostic accuracy [
1,
2,
3,
4]. Recent reviews have also highlighted the potential of IoMT-based point-of-care diagnostic platforms to address current limitations in decentralized testing environments [
5]. IoMT enables remote monitoring, real-time disease detection, and seamless data exchange between healthcare providers and diagnostic systems. This interconnected approach is particularly critical in point-of-care molecular diagnostics, where rapid and decentralized testing is essential for timely disease management.
Infectious diseases caused by various pathogens, such as bacteria, viruses, and parasites, pose a significant threat to public health due to their high transmissibility. Major infectious diseases, including respiratory illnesses (e.g., influenza, MERS, and COVID-19) and sexually transmitted infections (e.g.,
Chlamydia trachomatis and
Neisseria gonorrhoeae), have significantly affected public health and, in the case of respiratory epidemics, the global economy [
6,
7,
8,
9,
10,
11].
The COVID-19 pandemic, in particular, has demonstrated the devastating consequences of highly infectious diseases, not only in terms of morbidity and mortality but also through economic downturns, disruptions in education, and adverse effects on mental health [
10,
12]. As a result, mitigating the spread of infectious diseases has become a crucial public health priority, necessitating effective control measures such as patient isolation. Rapid and accurate diagnosis is essential for implementing timely isolation protocols and guiding appropriate treatment strategies. The ability to quickly detect and analyze pathogens plays a critical role in controlling outbreaks and informing public health responses [
10,
12,
13]. For instance, in the case of influenza, viral replication occurs within 72 h post-infection, making early antiviral administration (within 48 h of symptom onset) crucial for optimal treatment outcomes. Similarly, in conditions like severe sepsis, prompt pathogen identification is necessary for early antibiotic intervention, emphasizing the need for rapid point-of-care (POC) diagnostic methods.
Traditional diagnostic approaches rely on centralized laboratory testing, where patient samples must be transported to major hospitals or specialized laboratories. This process is time-consuming, delaying disease control efforts and reducing the effectiveness of early interventions. In contrast, point-of-care molecular diagnostic (POC-MD) methods offer a promising solution by enabling rapid and decentralized testing, facilitating early detection, infection control, and improved healthcare monitoring [
14]. The World Health Organization (WHO) initially established the ‘ASSURED’ criteria—Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment-free, and Deliverable—as the gold standard for ideal POC diagnostic devices [
5]. This has since evolved into the ‘REASSURED’ criteria, which incorporates real-time connectivity and ease of specimen collection to reflect the requirements of modern, networked diagnostics [
15]. The system proposed in this study was developed with these updated criteria in mind. To address key REASSURED elements in practical field use, the system incorporates a pre-filled reagent cartridge to reduce per-test cost (affordability), supports tunable thermal cycling protocols for robust operation across sample conditions (robustness), and allows direct sample input without nucleic acid extraction (equipment-free). These design choices aim to enhance deployability in low-resource environments.
Among the existing POC diagnostic techniques, rapid antigen tests and molecular diagnostics are widely utilized [
12]. Rapid antigen tests, which were frequently employed during the COVID-19 pandemic, provide quick and convenient testing; however, their accuracy limitations result in unreliable outcomes [
16]. Moreover, real-time polymerase chain reaction (real-time PCR) is the most widely recommended molecular diagnostic method for COVID-19 detection due to its high sensitivity and specificity. However, traditional real-time PCR systems are expensive and require skilled personnel, making them less accessible for point-of-care applications [
8,
17,
18,
19,
20]. Addressing these challenges requires the development of compact, cost-effective, and user-friendly real-time PCR systems that integrate automated sample processing, from nucleic acid extraction to detection, within a single embedded system [
21,
22,
23].
Embedded systems play a critical role in the development and operation of diagnostic devices. However, maintaining and modifying such systems often require significant time, cost, and resources. The adoption of open-source software and hardware offers an effective strategy for accelerating development, facilitating maintenance, and leveraging community-driven problem-solving [
24,
25,
26,
27,
28].
Advancements in information technology have also influenced the evolution of user interfaces (UIs) in embedded systems. While traditional graphical user interfaces (GUIs) have been implemented using built-in displays or PC applications, the increasing integration of web technologies is shifting GUI development towards web-based interfaces that offer seamless compatibility across multiple devices, including smartphones [
29,
30,
31,
32].
Furthermore, the connectivity of diagnostic systems has evolved from wired interfaces (e.g., USB) to wireless technologies such as Bluetooth and Wi-Fi, enhancing flexibility in device operation. The incorporation of cloud-based solutions enables remote data collection and system maintenance [
33]. However, traditional software architectures often struggle with device management in Industrial Internet of Things (IIoT) environments. A modular and distributed system architecture is necessary for efficient device lifecycle management, real-time operation, and seamless integration of networked components [
32,
34,
35,
36].
This study proposes an advanced system architecture for a fully automated POC-MD device, incorporating recent IT advancements. Unlike conventional hierarchical architectures, our approach employs a distributed system design with interconnected functionalities, enabling remote monitoring and control via networked communication. The system leverages an optimized application programming interface (API) protocol to ensure efficient real-time operation and integrates a web-based GUI for enhanced user interaction [
37,
38]. Additionally, the core functions of DNA extraction and real-time PCR are structured as independent modules, allowing for autonomous operation and improved diagnostic performance. Furthermore, the core functions of DNA extraction and real-time PCR are modularized as independently operable units, each accessible via a dedicated Web interface. This structure facilitates separate testing and debugging of each biochemical step, enhancing development efficiency, reliability, and maintainability.
Our previous study introduced a cloud-based software architecture for POC-MD systems [
39], demonstrating feasibility but revealing limitations in network latency, system synchronization, and user interaction efficiency. To address these challenges, this study aims to enhance the cloud-based architecture by optimizing network communication through WebSockets, thereby reducing latency. WebSocket-based communication has been shown to significantly reduce latency and overhead compared to REST or HTTP polling, particularly in real-time data transmission scenarios [
40]. Additionally, the microfluidic cartridge operation is refined to improve sample processing efficiency, ensuring more reliable and consistent diagnostic outcomes. To validate real-time system performance, a hardware-based emulator—improved from our previous implementation—was constructed to replicate system behavior under real-time conditions. This platform enabled system-level testing of the software architecture, communication protocols, and user interface responsiveness prior to clinical deployment. Furthermore, user interface responsiveness is enhanced to provide seamless real-time monitoring, ensuring a smooth and intuitive experience for medical professionals using the diagnostic system.
To address limitations in previous IoMT-based POC-MD systems—including high network latency, inefficient sample processing, and limited system validation—we propose a cloud-connected diagnostic platform with several key enhancements. These include the adoption of WebSocket communication to reduce latency, optimized control of microfluidic cartridge operations, and the use of a hardware-based emulator for software verification before deployment. By integrating these improvements, the proposed system aims to set a new standard for next-generation POC-MD methods, ensuring rapid, reliable, and accessible disease detection. While the proposed IoMT-based version has not yet undergone clinical testing, it builds upon a cartridge and detection architecture that was clinically validated in a commercial diagnostic device for the simultaneous detection of Chlamydia trachomatis and Neisseria gonorrhoeae.
3. Experimental Validation and Results
The proposed system was implemented and evaluated to verify its effectiveness. The hardware system was built around a Raspberry Pi 3A+ (Raspberry Pi Foundation, Cambridge, UK) as the main controller, selected for its compact size, low power consumption, fast boot time, adequate performance, and cost-effectiveness. Its large developer community also provides a robust support ecosystem, which facilitates debugging and long-term maintenance. A PIC18F4553 microcontroller (Microchip Technology Inc., Chandler, AZ, USA) was used for thermal control, leveraging our extensive prior experience and firmware know-how for precise PCR temperature cycling. Its built-in USB HID interface also simplified communication with the SBC. The motion control system utilized L6470 stepper motor drivers (STMircoelectronics, Geneva, Switzerland), connected through I2C using SC18IS602B bridge modules (NXP Semiconductors, Eindhoven, The Netherlands). The motor controller board managed the rotation valve motor, syringe motor, and filter wheel motor, integrating AMT203 rotary encoders (Same Sky, Lake Oswego, OR, USA) for precise positioning, while a servo motor controlled the magnet motor via PWM.
The software system, which integrates modular task and protocol managers with real-time controllers, was developed using Python’s FastAPI (Python 3.11.4) for HTTP and WebSocket APIs, with SQLite for database management, as illustrated in
Figure 5. The system supports WebSocket-based communication for real-time updates between the GUI and controller. This satisfies the REASSURED criterion of real-time connectivity. The web-based GUI was built using React and Bootstrap CSS and hosted on a Raspberry Pi web server. The system incorporated multicast Domain Name System (mDNS) to allow users to connect via hostname, derived from the MCU’s serial number, simplifying device discovery and access.
3.1. Task Manager and Protocol Manager
The task manager comprises an HTTP server thread handling API requests and a task sequence control thread managing DNA extraction and real-time PCR protocols. API requests for execution and termination are processed via HTTP and WebSocket, enabling concurrent system updates on the web-based GUI. The protocol manager, responsible for database interactions, supports operations such as retrieval, creation, modification, and deletion of protocols.
3.2. DNA Extraction Controller
The interaction diagram of the DNA extraction controller is shown in
Figure 6. It consists of an HTTP server thread, a command handler thread for parsing high-level commands into executable actions, an I2C control thread for stepper motor management, and a GPIO control thread for magnet servo motor control. The controller communicates with the task manager via WebSocket API for periodic status updates.
To ensure efficient and synchronized hardware control, the DNA extraction controller adopts a multi-threaded architecture. Commands are classified into two types: instance commands, which require immediate execution, and queued commands, which involve time-consuming hardware operations. The command handler thread executes instance commands directly—for example, status checks or parameter updates—without delay. In contrast, commands that involve stepper motors or servo actuation are placed into queues managed by the I2C and GPIO control threads, respectively. These control threads asynchronously process queued commands in order, allowing precise and non-blocking control of the hardware components.
The DNA extraction system includes refined high-level commands described in our previous study [
39], incorporating enhanced positioning and monitoring functions. Additional commands include precise motor positioning and jogging, along with AMT203-based homing capabilities. Motion controller parameters can also be adjusted for optimized DNA extraction.
Figure 6 provides an overview of the controller’s architecture and its integration with the task manager. A more detailed breakdown of the internal threading model and command handling structure is available in
Supplementary Figure S5.
3.3. Real-Time PCR Controller
Figure 7 depicts the interaction diagram of the real-time PCR controller, which comprises an HTTP server thread, a command handler thread, a USB/HID control thread for MCU communication, and an I2C control thread for filter wheel control. The PCR chip temperature is regulated using the USB/HID thread, controlling heater patterns, thermistors, and fans. Fluorescence detection is performed by managing LEDs and photodiodes through USB/HID, while filter wheels are controlled via I2C.
As illustrated in
Figure 8, the command handler thread processes HTTP requests by distinguishing between MCU-related commands and instance commands. The instance commands are executed immediately within the handler, while queued commands are forwarded to the USB/HID control thread for transmission to the MCU. This separation allows for asynchronous and non-blocking execution, improving system responsiveness during PCR operation.
The internal firmware of the MCU executes time-sensitive tasks such as temperature regulation, sensor reading, and LED control every 2 ms as part of the PCR control task. Additionally, a USB communication task is scheduled every 30 ms to handle transmission and reception of 64-byte packets. These periodic tasks ensure precise thermal cycling and reliable fluorescence data collection. A detailed breakdown of this firmware process, including timer-based scheduling, is provided in
Supplementary Figure S6.
3.4. Operational Procedure of the System
3.4.1. Protocol Manager Operation
Figure 9 shows the sequence diagram of the protocol manager, which handles HTTP requests for protocol retrieval, storage, modification, and deletion. Protocol selection triggers a “Select protocol” request, generating a binary file (“recent protocol”), which is accessed by the task manager for execution.
3.4.2. Protocol Execution and Stopping
Figure 10 outlines the process for initiating or terminating a protocol. The task manager updates the web-based GUI at 500 ms intervals via WebSocket. When execution begins, the task manager retrieves the DNA extraction protocol and sends it to the DNA extraction controller. Upon completion, the real-time PCR protocol is similarly executed. If a stop request is received, the appropriate controller is instructed to halt its operation. The final execution results are stored in the database for future reference.
3.4.3. DNA Extraction Protocol Execution
Figure 11 represents an example execution of the DNA extraction protocol. The DNA extraction controller transmits status updates every 100 ms via WebSocket. Commands are executed sequentially, ensuring precise control using absolute rotary encoders. Once completed, the task manager transitions to the real-time PCR protocol.
3.4.4. Real-Time PCR Protocol Execution
Figure 12 illustrates the execution of a real-time PCR protocol following DNA extraction. The real-time PCR controller updates the task manager every 100 ms via WebSocket and communicates with the microcontroller at 50 ms intervals over USB/HID. Commands are executed sequentially, with looped actions handled via “GOTO” commands. Upon completion, results are stored for analysis. During the “SHOT” phase, the SBC triggers excitation LEDs and rotates the filter wheel to align the emission filter with the photodiode. Once aligned, it commands the MCU to acquire fluorescence intensity via ADC. This is repeated sequentially for each target dye.
3.5. Performance Evaluation
3.5.1. Software Architecture Evaluation
To validate the proposed software architecture prior to full system integration, a hardware-based emulator—refined from our previous implementation [
39]—was constructed using the same system firmware and a web-based GUI. This platform enabled real-time testing of control logic, module communication, and interface responsiveness under practical operating conditions (
Figure S7). The system was integrated into a fully automated POC-MD device, currently undergoing clinical testing for simultaneous detection of
Chlamydia trachomatis (CT) and
Neisseria gonorrhoeae (NG). Four auxiliary tools were developed for system monitoring and troubleshooting:
- (1)
Extractor Controller Monitoring: Implemented using Vue.js, this web GUI includes command execution, register observation, and motor control functions.
- (2)
PCR Controller Monitoring: Developed in Jupyter Notebook 6.5.4, this tool verifies protocol execution, monitoring temperature, fluorescence intensity, cycle count, and remaining time.
- (3)
Diagnostic History Viewer: A standalone GUI displaying diagnostic records, including patient data and test results, with options for review and report generation.
- (4)
Reference Fluorescence Unit (RFU) Navigator: A Python-based tool for browsing and visualizing PCR amplification curves, allowing multiplex fluorescence comparison.
These tools were independently developed without modifying the core system architecture, demonstrating the flexibility and scalability of the proposed system for clinical applications.
This revised implementation result demonstrated robustness, automation capabilities, and adaptability for clinical molecular diagnostics of the proposed software architecture.
3.5.2. PCR Chip Verification with Standard DNA
To verify the performance of the PCR chip, amplification tests were conducted using a range of DNA concentrations. The reaction mixture consisted of 15 µL of master mix, 7.5 µL of PCR mix, 3 µL of distilled water, and 4.5 µL of DNA solution. The mixture was loaded into the cartridge’s PCR mixing chamber and subsequently transferred to the PCR chip for amplification.
Figure 13 presents the real-time amplification curves obtained from five replicates at each of five template concentrations, ranging from 400 to 0.04 copies per 30 µL reaction. The dashed line indicates the log RFU threshold of 6, which was empirically determined as the optimal threshold minimizing the average Ct variability across all concentrations.
Table 1 summarizes the mean and standard deviation of the Ct values for each concentration. Notably, successful amplification was observed in all five replicates even at the lowest tested concentration (0.04 copies per 30 µL reaction), although the amplification curves at this concentration exhibited greater variability and delayed threshold crossing compared to higher concentrations.
In this preliminary evaluation, 0.04 copies per 30 µL reaction (~1.3 copies/mL) yielded consistent amplification in all five replicates with Ct values under 40 cycles. While this result suggests that 0.04 copies/reaction is a viable limit of detection, a definitive LoD determination according to Clinical and Laboratory Standards Institute (CLSI) guidelines (≥95% detection in ≥20 replicates) will be conducted during the clinical validation stage.
3.6. Clinical Performance Context and Prior Validation
Although the proposed system is based on a previously validated cartridge and PCR architecture, the IoMT-based implementation itself has not yet been clinically evaluated due to ongoing regulatory processes. However, a previous study by Lim et al. [
24] evaluated the clinical performance of the earlier version of the LabGenius CT/NG platform (BIOMEDUX Co., Ltd., Suwon, Republic of Korea). That system shares the core cartridge structure and real-time PCR amplification design with the architecture presented here, including the closed-cartridge workflow and hardware-based fluorescence detection mechanism.
Chlamydia trachomatis and
Neisseria gonorrhoeae were selected as the target pathogens based on their global prevalence, high asymptomatic transmission rates, and their clinical importance in early detection and control through point-of-care diagnostics.
That system shares the core cartridge structure and real-time PCR amplification design with the architecture presented here, including the closed-cartridge workflow and hardware-based fluorescence detection mechanism. As only the software architecture and IoMT interface have been modified, while the cartridge and hardware remain unchanged, the prior biochemical validation remains valid for the current system configuration.
In the referenced study, a total of 510 clinical specimens (343 vaginal swabs and 167 urine samples) were tested using the LabGenius C-CT/NG-BMX assay (BIOMEDUX Co., Ltd., Suwon, Republic of Korea) and compared against a commercial system, BD MAX CT/GC/TV (Becton Dickinson, Franklin Lakes, NJ, USA). The overall percent agreement (OPA) with BD MAX was 89.2–93.3% for Chlamydia trachomatis and 97.7–98.8% for Neisseria gonorrhoeae, with Cohen’s kappa coefficients indicating strong agreement (0.78–0.91 for CT, 0.92–0.95 for NG). The complete diagnostic cycle—from sample lysis to result reporting—takes approximately 60 min, including DNA extraction and real-time PCR amplification.
However, when compared with consensus results based on multiple PCR assays, the OPA for NG dropped to 50.0%, suggesting that further optimization or test standardization may be required for certain specimen types or use cases.
The limits of detection (LoD95) of the prior version were 9.9 and 7.8 copies/μL for CT in swabs and urine, respectively, and 7.6 and 5.1 copies/μL for NG. Additionally, precision testing showed within-laboratory variation of less than 1.5% for Ct values, and no cross-reactivity was observed with non-target organisms or interferents.
These results, although obtained using a previous-generation system, support the feasibility of applying the proposed next-generation architecture in clinical environments, particularly for decentralized point-of-care molecular diagnostics.
4. Discussion
This study introduced a novel software architecture for a fully automated molecular diagnostic system, designed to improve operational efficiency and ease of use. Unlike traditional hierarchical software architecture, the proposed system adopted a distributed structure, dividing functionality between DNA extraction and real-time PCR processes. By using independent software modules that communicated via HTTP-based APIs, the system allowed for greater flexibility and modularity, enabling easier maintenance and upgrades. The integration of a web-based GUI enabled system access through a standard web browser without requiring specialized software. The adoption of a reactive framework allows clear separation between UX design and core system logic, thereby supporting future collaboration between software developers and interface designers during iterative refinement.
One of the key advantages of this system was its reliance on low-cost, open-source hardware components. The Raspberry Pi main controller, along with the PIC18F4553 microcontroller and L6470 motor controllers, provided a cost-effective alternative to commercial diagnostic systems while maintaining high performance. Furthermore, the software was developed in Python, a widely used and easy-to-learn programming language, making the system highly adaptable to future modifications and expansions. The adoption of WebSockets-based real-time communication significantly reduced latency, improving response times during protocol execution. Additionally, the system enhanced processing efficiency and minimized errors by optimizing microfluidic cartridge operations. The inclusion of a hardware-based emulator for pre-deployment validation ensured that potential issues were identified and resolved before implementation, further increasing reliability. The system’s architecture fulfills two core REASSURED criteria—real-time connectivity and ease of specimen collection—reinforcing its suitability for decentralized diagnostic applications and field deployment.
This interpretation is consistent with the recent literature emphasizing the importance of real-time connectivity and automation in IoMT-based molecular diagnostics [
1,
2]. The WebSocket-based control and feedback architecture implemented here enables low-latency interaction between the GUI and embedded controllers, enhancing operator awareness and workflow efficiency. Additionally, the system’s compatibility with non-invasive sample types and simplified cartridge operation supports the broader trend toward “sample-to-answer” diagnostic solutions that minimize user burden while maintaining analytical sensitivity [
15]. Moreover, the modular software architecture enables remote configuration and seamless protocol updates, allowing the system to evolve in response to clinical feedback or changing operational requirements in decentralized healthcare environments. Such remote configurability becomes especially valuable when managing a fleet of diagnostic devices deployed across multiple decentralized sites. Although the system is designed for IoMT-based connectivity, all core diagnostic functions are executed locally on the SBC. In the event of network instability or temporary cloud service interruptions, diagnostic processes continue uninterrupted, and data are cached locally for upload upon reconnection.
In a prior clinical study using an earlier generation of the proposed system, a total of 510 genitourinary specimens were tested using a self-contained cartridge and a real-time PCR architecture similar to that presented in this study [
41]. The results demonstrated high concordance with a commercially available PCR platform, with detection limits below 10 copies/μL and strong agreement in both CT and NG detection. While the current version has not yet undergone clinical testing, these findings provide indirect validation for the system’s design and highlight its clinical applicability in point-of-care diagnostic settings.
To further contextualize the proposed system, a comparison with recent IoMT-integrated nucleic acid amplification platforms is summarized in
Table 2. While previous studies [
42,
43,
44] have demonstrated portable diagnostic devices with IoMT features, most lack real-time bi-directional control, protocol-level reconfigurability, or sample preparation automation. Among these, the Raspberry Pi–based architecture proposed in [
44] shares a compatible hardware foundation but implements only partial monitoring via a web dashboard. In contrast, our system leverages WebSocket-based architecture to enable comprehensive device interaction and control, including emulator-driven protocol testing and automated cartridge workflows.
The proposed system can be integrated for a broad range of applications beyond the current study. In clinical diagnostics, it can be deployed in hospitals, small clinics, and field laboratories to provide rapid, decentralized disease detection. The previous standalone system (LabGenius) is currently undergoing clinical testing at a public health center in Republic of Korea, with regulatory approval targeted for Q3 2025. The IoMT-based system proposed in this paper shares the same cartridge and detection architecture and is scheduled for clinical validation in Q4 2025, pending IRB approval.
Its real-time monitoring capabilities also make it suitable for epidemiological surveillance, allowing for early outbreak detection and response. Additionally, the system’s integration with web-based technologies opens possibilities for remote healthcare applications, enabling decentralized testing and analysis through telemedicine platforms. The system can be further improved by integrating artificial intelligence algorithms for automated result interpretation, reducing the need for manual analysis. Miniaturization of the device could enhance its portability, making it more accessible for point-of-care testing. Furthermore, expanding its diagnostic capabilities to include additional disease targets would increase its applicability in diverse healthcare settings.
At present, specific AI models have not yet been implemented; the proposed IoMT system facilitates collection of comprehensive RFU curves and thermal cycling profiles. These data may support future development of more robust result classification algorithms beyond conventional cycle threshold–based methods.
In addition to swab and urine specimens, ongoing feasibility studies have demonstrated compatibility with blood and sweat samples using customized extraction protocols. The modular cartridge design and programmable workflow enable straightforward adaptation to additional sample types.
While the proposed system builds upon a previously validated cartridge and PCR architecture, direct clinical validation of this specific IoMT-based implementation has not yet been conducted due to ongoing regulatory processes. The current limit-of-detection (LoD) assessment was based on five replicates, and although results were consistent, the evaluation does not meet statistical criteria for formal LoD confirmation. Similarly, device-to-device reproducibility has not yet been established, as only a single prototype was tested. These limitations will be addressed in the clinical validation and scale-up phases, which will include ≥20 replicate tests for LoD determination and inter-device performance comparisons under standardized conditions.
As part of this process, data privacy and cybersecurity considerations—such as TLS-encrypted communication, token-based access control, and compliance with healthcare regulations—will be addressed during productization and large-scale deployment. In the current prototype, each functional module (e.g., extraction and amplification) operates as an independent FastAPI-based WebSocket server, and the system controller exposes REST APIs via a FastAPI HTTP server. This architecture enables modular development and real-time coordination within a local network. However, secure deployment will require full integration of security protocols across all communication channels. While modern cloud platforms provide encryption, authentication, and logging primitives, these features must be appropriately configured and integrated by the development team to meet end-to-end security requirements in accordance with HIPAA, GDPR, or equivalent standards.