Uv 1600pc spectrometer

Lysogeny broth was used to grow S. aureus bacteria at 37 °C overnight. The grown solution was serially diluted from 1/10 to 1/10⁹ times in PBS. Each solution was spotted onto agar plates (3 × 10 μL), as well as measured using a UV-1600PC spectrometer (VWR International, Mississauga, ON, Canada) to measure the optical density at 600 nm (OD600). The plates were incubated overnight at 37 °C and spot counted to calculate CFU per OD600 (see Supplementary Material, Section S3).
For TSM measurements, S. aureus, E. coli, or P. aeruginosa bacteria was grown overnight at 37 °C. The next day, 1 mL of the bacteria solution was centrifuged at 14,500× g RPM (5 min). A total of 1 mL of PBS was used to resuspend the bacteria pellet. The OD600 of the solution was used to calculate the base CFU, and then the solution was diluted to the desired CFU. To prepare milk samples, the diluted PBS bacteria solution was centrifuged at 14,500× g RPM (5 min) to pellet the bacteria, and then the bacteria was resuspended in milk.

Characterization of the different synthesized photosensitizers was achieved by ¹H NMR spectroscopy recorded on a 600 MHz Bruker AVANCE NEO spectrometer and HR-MS (ESI positive, direct injection) recorded with a Bruker Impact II spectrometer. All UV-Vis spectra were recorded using a UV-1600PC spectrometer from VWR with a resolution of 1 nm. Surface analysis of the npAu supports and the final hybrid materials was performed on a scanning electron microscope (SEM, Supra 40, Zeiss) operated at 15.0 kV acceleration voltage, 300 pA probe current and 10 mm working distance and equipped with a Bruker XFalsh 6/30 EDX detector. For the quantification of immobilized photosensitizer, the hybrid material (10 mg) was dissolved in ultrapure aqua regia (2 mL) prior to determination by ICP-MS using an iCAP-Q spectrometer form Thermo Fisher Scientific.