Nucleic acid detection methods enable the rapid identification of specific genetic indicators. However, their extensive application is limited by the sequential use of multiple instruments and the high technical requirements for operators. A fully integrated nucleic acid analysis system can automate the sample-to-answer detection process. However, nucleic acid amplification via PCR technology is time-consuming, and stringent requirements are placed on temperature control accuracy and heating/cooling speed, which increases the manufacturing cost of the corresponding instruments. These systems also lack the flexibility to accommodate variations in sample preprocessing methods and nucleic acid extraction protocols for different types of clinical samples. To address these challenges, we present a novel, fully integrated nucleic acid analysis system that contains a syringe-based sample processing and nucleic acid extraction module, a fully enclosed PC-based multiplexed detection microfluidic chip, and a nucleic acid amplification product detection module. We applied this system for the precise medical testing of various pathogenic infections in gynecology. The results indicate that our system can achieve precise medical molecular diagnosis with the fully integrated automation of a micro-nano reaction system, as well as speedy processing, high sensitivity and specificity, and multiplexed parallel detection. The system also shows potential applications in the in vitro identification of genetic and other nucleic acid-related diseases, holding significant social and economic value for the prevention and control of major diseases in China.

This paper presents a fully integrated nucleic acid analysis system based on a syringe microfluidic chip. The system consists of two modules. The first is an automated syringe nucleic acid extraction module that accommodates multiple nucleic acid extraction techniques based on different clinical sample types. This process involves four primary steps: sample loading, incubation, washing, and lysis by heating and shaking. The second module is an isothermally amplified nucleic acid detection module capable of simultaneous multivariate detection. The nucleic acid amplification and detection platform, based on microfluidic technology, includes a disk-based microfluidic chip that serves as a nucleic acid isothermal amplification carrier, a temperature control platform ensuring precise isothermal amplification of nucleic acids, a fluorescence detection platform for real-time monitoring of nucleic acid amplification, and a software analysis platform for controlling and analyzing the entire system. The two modules perform their respective functions independently and can also be combined into an integrated syringe-microfluidic chip nucleic acid analysis system, forming a fully integrated micro-nano detection platform that rapidly automates both nucleic acid extraction and detection and is capable of detecting multiple indicators in parallel.

The fully integrated system was evaluated using a standard Candida tropical culture strain and 64 clinical swab samples obtained from patients with vulvovaginal candidiasis. The results show that the detection concentration threshold of 3.95×10² CFU/mL was comparable to that of the conventional nucleic acid detection method, which involves extracting nucleic acid with a reagent kit and amplifying it on a commercial PCR machine. The sample preparation is more convenient and fast, with only one sample loading step, and nucleic acid extraction takes 10 min, resulting in significant time and labor savings (Table 1). A chi-square value of 1 and a Kappa value of 0.950 indicate a strong correlation with the gold standard method of clinical microbial culture (Table 2). Although a false-negative result with two samples containing Candida albicans was obtained, optimizing the primer sequences and reaction systems for isothermal amplification can address this problem. Therefore, this comprehensive integrated nucleic acid detection platform provides rapid and accurate multiplexed detection for the diagnosis of clinical microbial pathogen infections and has advanced technological capabilities.

In this study, a fully integrated nucleic acid analysis system based on a syringe microfluidic chip is developed, which consists of two modules. One is an automatic syringe nucleic acid extraction module, and the other is an isothermally amplified nucleic acid detection module based on a microfluidic chip. The system was tested using a standard Candida tropical culture strain and 64 clinical swab samples of vulvovaginal candidiasis. The results show that the minimum detection concentration of the bacterial solution in the system is 3.95×10² CFU/mL, and a more convenient and rapid sample preparation is achieved with only one sample loading step with a nucleic acid extraction duration of 10 min. Compared with the gold standard culture method, a chi-square test and Kappa value of 1 and 0.950, respectively, indicate that there is no significant difference between the two methods, with high consistency. The syringe-microfluidic chip-based, fully integrated nucleic acid analysis system detailed in this study provides a reliable platform for the rapid detection of nucleic acids using multiple indicators in a micro-nano system. The system offers precise detection and convenient analysis and supports applications in clinical medicine, grassroots screening for infectious diseases, health prevention programs, and basic biomedical research. This underscores the significance of this system in molecular diagnostics with in vitro precision in clinical settings, such as genetic disease identification and tumor molecular marker co-detection, as well as its potential uses in food safety and preventive healthcare applications.