Aberrant assembly of amyloid-β (Aβ) is a central pathological feature of Alzheimer’s disease, and photoactive agents have been explored as a way to modify Aβ assembly through light-triggered oxidative chemistry. Here, phosphate-silane porphyrin silicon nanoparticles (PSiPnPs) were prepared by hydrothermal synthesis at 200 °C for 24 h. Five TCPP:phosphate-silane molar ratios (1:50–1:400) were evaluated. A 1:100 formulation (PSiPnPs-2) was selected for further study because it formed particles with a hydrodynamic diameter of 50.3±5.4 nm and a negative zeta potential of -41.9 mV. Transmission electron microscopy showed discrete nanoscale particles. PSiPnPs-2 displayed a strong absorption maximum at 414 nm and fluorescence bands centered near 645 and 705 nm, with signal increasing over the tested concentration range (10–50 µg/mL). Qualitative electron micrographs of Aβ incubated with 50 µg/mL PSiPnPs-2 for 24 h differed from Aβ-only images, consistent with altered aggregate morphology. These preliminary data establish the synthesis and physicochemical characterization of a photoactive porphyrin–silicon nanosystem; quantitative aggregation, reactive-oxygen-species, photostability, cytocompatibility, and light-versus-dark experiments are required before concluding that the formulation inhibits Aβ aggregation or has therapeutic potential.