Near-infrared excited core-shell upconversion composites for living cells proteome labeling

Near-infrared excitation effectively eliminates interference from intracellular visible-light-absorbing photosensitizers for living cells proteome labeling. Herein, a core-shell upconversion composites (CS-NaYF₄@MOF) were developed for NIR activated proteome proximity labeling in living cells. A NIR-responsive photosensitizer was fabricated by in situ growth of a Cu-TCPP-based metal-organic framework (MOF) shell on Nd³⁺-sensitized core-shell upconversion nanoparticles. Upon 808 nm NIR excitation, the composites generate green upconversion luminescence to efficiently activate Cu(II) meso-Tetra(4-carboxyphenyl)porphine (Cu-TCPP) for reactive oxygen species production, enabling protein labeling in living cells with nucleophilic substrate. The characterizations confirm the successful formation of a crystalline MOF coating with homogeneous elemental distribution. Cellular assays reveal low photo-toxicity, allowing time- and concentration-dependent protein labeling under NIR light irradiation. By combining click chemistry and mass spectrometry, high-throughput proteome identification in living cells is successfully realized. This work not only extends the application of MOF-based materials in proteomics, but also offers a NIR excited strategy for living cells proteome labeling.