Pathogenic microorganisms, antibiotic resistance genes (ARGs), and exogenous pathogenic nucleic acids lurk in urban domestic sewage, hospital wastewater, industrial effluent, and watershed networks. These "invisible risks" form the core issues of water environment safety and public health prevention and control.

Figure 1: The fate and potential exposure pathways of infectious viruses in the urban water cycle Source: Wigginton K.R., et al. Emerging Investigators Series: The source and fate of pandemic viruses in the urban water cycle. 2015. (Translated)

How can we accurately "fish out" these invisible risks from complex wastewater matrices? The answer lies in digital PCR.

Wastewater testing is inherently complex.

First, target nucleic acids are usually present in extremely low concentrations. In environmental samples, viruses, pathogenic bacteria, or specific functional genes may exist in minuscule amounts. Particularly in the early stages of disease outbreaks or initial contamination, target molecule concentrations often fall far below the stable detection limit of traditional methods.

Second, wastewater sample matrices are highly complex. Wastewater from different sources may contain humic acids, polysaccharides, proteins, and other PCR inhibitors that reduce amplification efficiency, leading to biased test results.

While quantitative real-time PCR (qPCR) relies on standard curves for absolute quantification, digital PCR (dPCR) partitions the reaction mixture into tens of thousands of independent micro-reactions. By calculating the ratio of positive to negative reactions using Poisson statistics, dPCR achieves absolute quantification of target nucleic acid molecules without standard curves.

Typical Applications of Digital PCR in Wastewater Testing

• Pathogen Monitoring & Epidemiological Early Warning: Human viral nucleic acids carried in wastewater reflect community infection status. Leveraging high sensitivity for low-abundance targets, dPCR monitors viral nucleic acids to provide data support for public health risk warnings. For example, during viral epidemics, detecting viral-specific nucleic acid fragments in wastewater helps assess community transmission trends, shifting the strategy from "passive testing" to "proactive warning."

• Antibiotic Resistance Gene (ARG) Detection: Antibiotic resistance is a critical global public health concern. As a key environmental medium for microbial transmission and gene exchange, wastewater harbors diverse resistance genes. Digital PCR enables accurate quantification of low-abundance ARGs, providing reliable data support for wastewater treatment evaluation and environmental resistance risk analysis.

• Microbial Contamination & Water Quality Assessment: Traditional culture methods are time-consuming and cannot cover unculturable microorganisms. Nucleic acid-based dPCR directly analyzes genetic markers of target microorganisms to boost efficiency, making it well-suited for monitoring sewage treatment plants, industrial wastewater, and ecological water bodies.

To address challenges such as low-concentration targets, complex matrices, and high accuracy requirements, JLM-Lifetech provides high-sensitivity, high-stability, and high-efficiency dPCR solutions for environmental molecular testing using an all-in-one integrated microfluidic chip technology.

Core Technology: All-in-One Integrated Microfluidic Chip

Figure 2: All-in-One Integrated Microfluidic Chip

The JLM-Lifetech digital PCR system utilizes an innovative integrated microfluidic chip design, combining the advantages of droplet and chip-based dPCR. By integrating droplet generation, PCR amplification, and fluorescence detection onto a single platform, it achieves a "sample-in, result-out" enclosed workflow.

Once loaded, samples are driven by the microfluidic system to generate a dense, uniform single layer of matrix microdroplets. PCR amplification occurs directly on-chip without droplet transfer operations, eliminating sample loss and cross-contamination at the source. Precise temperature control enables rapid thermal cycling, significantly shortening amplification time.

In complex wastewater testing, this technology guarantees reliable detection of low-abundance targets through droplet uniformity, precise temperature control, and contamination prevention.

Additional Advantages of the JLM-Lifetech Digital PCR System:

• Single-Copy Sensitivity: Reaches a limit of detection down to the single-copy level, effectively overcoming low target abundance and complex background interference in wastewater samples.

• Advanced Multiplexing Capability: Expands beyond hardware channel limits to quantify more targets in a single reaction, saving samples and reagents while cutting turnaround times.

Figure 3: Using the TaqMan probe method with FAM, HEX, ROX, and Cy5 channels (configured with 2, 2, 3, and 2 probes respectively), a 9-plex dPCR system is established. 2D plots across six channel combinations demonstrate clear resolution of positive droplets for each target.

• Intelligent Image Analysis: Supports visual backtracking of positive droplets to identify and correct potential false positives, enhancing specificity and accuracy.

• Open Platform: Compatible with third-party reagents, lowering operational costs.

DiOne: Fully Automated All-in-One System

• Throughput: 4–32 samples/batch

• Optical Channels: 4/5/6/7 channels

• Droplet Generation: 20,000–25,000 droplets

Digital Matrix: Microdroplet Matrix Generator & Thermal Cycler + Microdroplet Matrix Reader

• Generator & Thermal Cycler: 1–32 samples/batch, 20,000–30,000 droplets

• Reader: 3/4/5 channels, 1–16 samples/batch

From environmental risk monitoring to public health early warnings, and pathogen detection to resistance gene profiling, wastewater surveillance is entering a more precise and efficient molecular era. The JLM-Lifetech digital PCR system brings high-sensitivity, high-precision, and automated molecular testing capabilities to environmental monitoring, empowering CDCs, environmental protection agencies, research institutes, testing labs, and environmental sectors.