1：Experimental Design and Method Selection:

A two-step synthesis approach was used: first, chitosan-coated gold nanoparticles (chit-AuNPs) were synthesized as seeds, then a silver shell was grown stepwise via reduction of Ag ions with ascorbic acid. The nanoparticles were characterized using TEM, HAADF-STEM, EDX, UV-Vis spectroscopy, zeta potential measurements, and SERS. In vitro studies included cell proliferation assays, dark field microscopy, and confocal Raman microscopy for cellular uptake and pH sensing.

2：Sample Selection and Data Sources:

Human ovarian adenocarcinoma cells (NIH:OVCAR-3) were used. Nanoparticles were synthesized from chemical reagents including HAuCl4, chitosan, AgNO3, ascorbic acid, and 4MBA.

3：List of Experimental Equipment and Materials:

Equipment included TEM (TecnaiG2 F20 X-TWIN), UV-Vis spectrophotometer (Jasco V-670), zeta potential analyzer (Malvern Zetasizer Nano ZS-900), confocal Raman microscope (CRM alpha 300R, WITec GmbH), dark field microscope (Zeiss Axio Observer Z1), atomic absorption spectroscopy (Avanta PM, GBC-Australia). Materials included HAuCl4, chitosan, AgNO3, ascorbic acid, 4MBA, cell culture reagents.

4：Experimental Procedures and Operational Workflow:

Synthesis involved preparing chit-AuNPs, then adding AgNO3 aliquots stepwise to form chit-Au-AgNPs, followed by labeling with 4MBA. Cells were incubated with nanoparticles, and assays were performed for proliferation, dark field imaging, and SERS imaging under 532, 633, and 785 nm lasers.

5：Data Analysis Methods:

Data analysis included statistical analysis of nanoparticle size from TEM, spectral analysis of UV-Vis and SERS data, zeta potential evaluation, and image processing using software like ZEN 2012 and WITec Project Four Plus.