Development of a portable real-time PCR system for on-site detection of airborne bacteria

• A portable real-time PCR device was designed for on-site bacterial detection • This platform employs a two-stage PCR amplification strategy • The device performance matches that of standard PCR equipment • This platform effectively detects low-abundance airborne bacterial targets • It can be widely used for public safety, as it could help prevent epidemics. Control over air quality and safety is critical for public health because bio-aerosols, including viruses and airborne bacteria, present significant health risks. Therefore, rapid and reliable on-site bacterial detection is essential. In this study, we present a portable, real-time polymerase chain reaction (PCR) device for high-sensitivity, practical on-site bacterial detection. The system employs a two-stage PCR amplification strategy, enabling the detection of low-abundance bacterial targets, including Staphylococcus aureus ( S. aureus ) , Staphylococcus epidermidis ( S. epidermidis ) , Bacillus cereus ( B. cereus ), and Micrococcus luteus ( M. luteus ), commonly present in bio-aerosols. The analytical performance of the portable real-time PCR platform is comparable to that of standard laboratory PCR equipment, while offering key advantages in portability, cost-efficiency, and on-site usability. Using thermally lysed bacterial samples, the limits of detection (LOD) were determined to be 6.0 × 10¹, 6.0 × 10⁰, 1.62 × 10¹, and 3.0 × 10¹ CFU/mL for S. aureus, S. epidermidis, B. cereus , and M. luteus, respectively. The system detects target bacteria within 2 hours, demonstrating consistent detection performance compared to a standard real-time PCR system under the tested conditions. Field testing at four independent real-world sites further validated its applicability. This portable PCR system provides a practical, field-deployable diagnostic tool for airborne bacterial monitoring and has strong potential to support early detection and rapid response during infectious disease outbreaks.