1：Experimental Design and Method Selection:

The study involved synthesizing amphiphilic redox-responsive conjugates (HSC and HEC), preparing self-assembled nanoparticles, encapsulating perfluorohexane (PFH), and evaluating their properties through various in vitro and in vivo assays. Theoretical models include redox-responsive behavior and oxygen delivery mechanisms.

2：Sample Selection and Data Sources:

Human breast carcinoma cell line MDA-MB-231 was used for in vitro studies, and BALB/c nude mice with MDA-MB-231 tumor xenografts for in vivo studies. Data were acquired from laboratory experiments.

3：List of Experimental Equipment and Materials:

Instruments include dynamic light scattering (DLS) for size measurement, transmission electron microscopy (TEM) for morphology, UV-vis spectrophotometer for absorption, fluorescence spectrophotometer for fluorescence, gas chromatography mass spectrometry (GC-MS) for PFH confirmation, confocal laser scanning microscope (CLSM) for cellular imaging, flow cytometry for singlet oxygen analysis, IVIS Lumina III imaging system for fluorescence imaging, MSOT system for photoacoustic imaging, and MTT assay for cytotoxicity. Materials include sodium hyaluronate, chlorin e6, cystamine dihydrochloride, ethylenediamine, EDC, NHS, Sulfo-NHS, pyrene, PFH, DMEM, FBS, Hoechst 33342, ROS Assay Kit, and others as listed in the Experimental Section.

4：Experimental Procedures and Operational Workflow:

Synthesis of HA-cys and HA-eda, followed by conjugation with Ce6 to form HSC and HEC. Nanoparticles were prepared by sonication, and PFH was encapsulated via ultrasonic emulsification. Characterization included DLS, TEM, UV-vis, fluorescence, and GC-MS. Redox-responsive behavior was tested with DTT. Oxygen release was measured with a dissolved oxygen meter. Singlet oxygen generation was assessed using ABDA. Cellular uptake, ROS generation, and phototoxicity were evaluated in MDA-MB-231 cells. In vivo studies involved fluorescence and PA imaging, hypoxia assessment, and PDT efficacy in tumor-bearing mice.

5：Data Analysis Methods:

Statistical analysis used one-way ANOVA with Tukey post hoc correction. Data are presented as mean ± standard error, with significance at p < 0.05.