This project includes design, simulation and preliminary tests of a photonic biochip for bacterial killing through the temperature increase caused by the heating of gold nanoparticles . The proposed biochip is made of PolyDiMethylSiloxane (PDMS) in which microfluidic channels, gold nanorods (GNRs) and optical waveguides are combined and integrated. Microfluidic channels and optical waveguides are made on separated substrates then coupled to form a single PDMS chip. GNRs are deposited on the top surface of the substrate which includes the optical waveguides. Microfluidic channels are used to transport a bacterial solution. Optical waveguides confine near infrared light (NIR) at a wavelength of 810 nm with a power of about 0.5 W/cm2. NIR light beams activate the GNRs exciting local plasmon resonances, which determine a temperature increase above 45 °C, able to kill the bacteria flowing in the microfluidic channel.
The solution with bacteria will be introduced in the microfluidic channel by using an inlet micropump and extracted at higher temperature by means of an outlet micropump after photothermal treatment. The output solution will be characterized to check presence of bacteria. To validate the proposed approach, a strain of Escherichia coli (E. coli) has been selected as a representative type of bacteria, having a great impact as it causes severe illness in humans since it is found in the lower intestine of warm-blooded organisms.
The proposed plasmonic integrated microsystem will be thoroughly investigated highlighting the structure-function relation and assessing the antimicrobial activity by means of viability assays.
This proposal is a preliminary step toward developing integrated nanomedicine, for guiding, and optimization of thermal-based laser treatment. The research involves multidisciplinary expertise ranging from photonics, electromagnetism, biology, advanced microscopy, biomedical engineering.
