Development of a handheld cold plasma device for surface treatment and antibacterial applications

Abstract

This study introduces a compact and handheld cold atmospheric plasma (CAP) device for precision surface treatment and antibacterial applications. The device operated on a 3.7 V lithium-ion cell and featured a high-voltage module generating 20 kV to ionize argon gas through a needle-ring electrode structure, ensuring efficient and controlled plasma generation. The components were enclosed in a gun-shaped housing with dimensions of 245 × 32 × 58 mm, designed and fabricated using 3D printing technology. Experimental results determined the optimal parameters for the proposed system, with a 1 cm electrode gap and a gas flow rate of 2 l min−1, generating a plasma stream with a maximum intensity and a length of 9 mm. The proposed system was evaluated for its applicability in microfabrication and antibacterial treatment. Experimental results demonstrated its effectiveness in bonding glass and polydimethylsiloxane (PDMS) for microfluidic chip fabrication, achieving a strong, durable seal that prevented leakage within the microchannels. Additionally, antibacterial assessments targeting E. coli indicated pronounced bacterial growth suppression in 90–120 s of plasma exposure at a gas flow rate of 4–5 l min−1, whereas shorter exposure durations (30–60 s) resulted in limited disinfection. The most pronounced antibacterial effects were achieved under either of the following conditions: a flow rate of 4 l min−1 with an exposure distance of 8 mm for 90 s, or a flow rate of 5 l min−1 at a distance of 15 mm for 60 s. The optimized design of the device offers a low-cost and efficient alternative to conventional plasma systems, addressing limitations related to high cost and laboratory confinement. These findings highlight the potential of the proposed system for practical applications in microfluidic chip fabrication, medical sterilization, and food safety, with minimal resource consumption.