Ivis lumina xr 3 system

All chemicals were acquired from Sigma-Aldrich (Shanghai, China) unless otherwise stated. DSPE-PEG2000 was purchased from Avanti (Alabaster, AL, USA). A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) Kit was bought from KeyGen Biotech. Co., Ltd., (Nanjing, China). DPPC was bought from Sigma-Aldrich. ICG was acquired from MedChemExpress (Shanghai, China). IR-HS was synthesized according to our previously reported synthesis method [38 (link)].
Absorption and fluorescence spectra were performed on an Ocean Optics UV–Visible spectrometer (Ocean Optics, Dunedin, FL, USA) and HORIBA Jobin Yvon Fluoromax-4 fluorescence spectrometer (HORIBA Jobin Yvon, Paris, France), respectively. Fluorescence images were acquired on an Olympus IX73 fluorescent inverted microscope (Olympus LS, Tokyo, Japan). Dynamic light scattering (DLS) was conducted on a 90 Plus/BI-MAS equipment (Brookhaven, New York, NY, USA). Transmission electron microscopy (TEM) analysis was performed on a JEM-1011 transmission electron microscope (JEOL, Ltd., Tokyo, Japan). The MTT analysis was conducted on a microplate reader (Tecan, Grödig, Austria). The fluorescence images in mice were collected using an IVIS Lumina XR III system (PerkinElmer, Waltham, MA, USA).

To examine the ability for NIR FL and PA bimodality imaging of ALP activity in cells, HeLa or HEK29T cells were seeded in 10-cm dishes at a density of 4 × 10⁶ cells/well and allowed to grow overnight. Then, P-CyPt (10 μM) or Pt^IVNPs (10 μM) in FBS free DMEM (4 mL) was added into wells and incubated at 37 °C for 30 min. To inhibit the ALP activity, cells were pretreated with ALP inhibitor Na₃VO₄ (10 mM) for 20 min, and then incubated with P-CyPt (10 μM) for another 30 min. To examine NIR FL and PA bimodality imaging of intracellular GSH-triggered disassembly process, P-CyPt (10 μM) in FBS free DMEM (4 mL) was added into HeLa cells, and incubated at 37 °C for 30 min. Then, the medium was removed and the cells were incubated in refreshed DMEM medium (10% FBS) for another 3 h. Then, the mediums of above mentioned cells were removed, and the cells were washed with PBS (1 mL) once. Trypsin (1 mL) was added to detach the cells, and the cell pellets were then collected after centrifugation at 161 × g for 4 min. The NIR FL images (λ_ex/em = 670/750 ± 50) of the cell pellets were acquired on the IVIS Lumina XR III system (PerkinElmer), and the PA images of the cell pellets at both 700 and 750 nm were acquired on the Vevo 2100 LAZR system (FUJIFILM VisualSonics).