A lab-on-a-chip utilizing microwaves for bacterial spore disruption and detection

Area of Science:

• Biotechnology
• Microfluidics
• Spectroscopy

Background:

• Bacterial spore contamination poses significant risks and economic losses in agriculture, food, and healthcare.
• Current methods for bacterial spore detection are hindered by the spores' resistance to disruption, complicating biomarker release.

Purpose of the Study:

• To demonstrate the efficacy of a compact microfluidic lab-on-chip device utilizing a coplanar waveguide (CPW) for bacterial spore disruption.
• To investigate the release of calcium dipicolinic acid (CaDPA) as a biomarker following CPW-induced disruption.
• To assess the potential for improved spore detection through this novel disruption technique.

Main Methods:

• Fabrication of a microfluidic chip incorporating a coplanar waveguide (CPW) operating at 2.45 GHz.
• Application of electric fields generated by the CPW to bacterial spores within the microfluidic channel.
• Detection of CaDPA release using fluorescence spectroscopy and laser tweezers Raman spectroscopy (LTRS).
• Microscopic analysis of spore integrity using scanning electron microscopy (SEM).

Main Results:

• The CPW generated a high electric field (∼10 kV/m) at low power (1.2 W) with minimal heating.
• LTRS confirmed significant CaDPA loss from individual spores post-exposure, increasing with power.
• CaDPA was detected in only 22% of treated spores versus 71% in controls; SEM showed visible spore disruption.

Conclusions:

• The developed microfluidic CPW system offers an efficient, low-power method for bacterial spore disruption.
• This technique facilitates the release of CaDPA, a key biomarker, enabling more effective spore detection.
• The study highlights the potential of CPW technology for advancing spore detection in critical industries.