Nanoplus

DSPE‐mPEG₂₀₀₀ was purchased from Shanghai Yare Co. Ltd. ROS probes, TEMPO, DMPO, SOSG, and DCFH‐DA, were purchased from Adamas‐Beta. Hypoxia probe ROS‐ID was purchased from Enzo Life Sciences Co. Ltd. (USA). All other chemical agents were purchased from Shanghai Titan Scientific Co. Ltd. Nuclear Magnetic Resonance (NMR) spectra were measured utilizing JEOL ECZ‐400 spectrometer (400 MHz) and Bruker Ultra Shield Plus (400 MHz). Mass spectroscopy of photosensitizers was measured using MALDI‐TOF mass instruments. The diameter of nanoparticles was characterized by a dynamic light scattering particle size analyzer (NanoPlus, Micromeritics Instrument Co. Ltd.). UV–vis absorption was measured by a UV‐3600 Shimadzu UV–vis–NIR spectrometer. Fluorescence spectra were tested with a Thermo Fisher fluorophotometer, and the fluorescence decay was obtained on Edinburgh FLS 1000 instrument. Confocal fluorescence imaging was carried out employing Olympus IX 70 imaging systems. In vivo fluorescence images of tumor‐bearing mice were conducted by using Fluor Vivo 2000 INDEC imaging system.

The morphology of N-CDs was characterized by transmission electron microscopy (TEM) (FEI Tecnai G2, USA) at an accelerating voltage of 200 kV. A drop of sample solution was placed on a copper grid that was left to dry before being transferred into the TEM sample chamber. Fluorescence experiments and ultraviolet-visible (UV-vis) measurements were carried on F-4600 spectrophotometer (Hitachi, Japan) and Agilent 8453 UV-vis spectrophotometer (USA), respectively. The fluorescence emission spectra of N-CDs were collected from 385 nm to 510 nm at room temperature with an excitation wavelength at 272 nm. The X-ray photoelectron spectroscopy (XPS) analysis was conducted by an ESCALAB 250Xi instrument (Thermo Fisher Scientific, USA) equipped with Al Kα (1486.6 eV). Fourier transform infrared (FT-IR) spectrum was recorded in the range of 4000–400 cm⁻¹ by using a NEXUS-470 spectrometer (Nicolet, USA) with KBr pellets. The Quantum Yield and lifetime of N-CDs were determined by using a FLS 980 fluorescence spectrophotometer (Edinburgh, UK). The Zeta potential measurements were carried out by using a zeta/nano particle analyzer (Nano Plus, Micromeritics Instruments) at room temperature.

Prior to physiochemical characterization, the green synthesized Ag NPs sample was dried at 60 °C under vacuum. Ultraviolet-visible spectrum of Ag NPs was recorded using Jasco V-750 (India) UV-Vis spectrophotometer. FTIR spectrum was obtained using Perkin Elmer Spectrum Two (USA) FTIR spectrophotometer. The scanning range and resolution were 4000–400 cm⁻¹ and 4 cm⁻¹, respectively. The crystalline structure of the Ag NPs was investigated by X-ray diffraction studies (D8 Advance Bruker X-ray diffractometer, USA). The X-ray diffractometer was operated at the voltage of 40 kV and current of 40 mA. The radiation source was Cu/kα (λ = 1.5412 Å). The size distribution of Ag NPs was evaluated using DLS (Micromeritics Nano Plus, Germany). HR-SEM images were obtained using FEI Quanta FEG 200 high resolution scanning electron microscope equipped with the energy dispersive X-ray spectrophotometer. HR-TEM analysis was performed using Jeol/JEM 2100 high resolution transmission electron microscope operated at the accelerating voltage of 200 kV. For HR-TEM analysis, the samples were prepared by drop casting 10 µL of Ag NPs–ethanol dispersion onto a carbon coated copper grid. The surface area of the Ag NPs was determined by Brunauer–Emmett–Teller surface area analyzer (BET, Nova e2200 Quantachrome, India).