The DMA can react irreversibly with 1O2 to yield Bcl-2 inhibitor an endoperoxide. The reaction could be monitored by recording the decrease in the absorption at 377 nm. In a typical experiment, 0.105 mg of the Aurod@pNIPAAm-PEGMA

nanogel loaded with 0.0135 μmol ZnPc4 was dispersed in 3 mL of DMF, and then, 0.45 μmol DMA was added. Pure ZnPc4 (0.0135 μmol) was used as a control. The solutions were then irradiated with a LED lamp (680 nm, 10 mW/cm2) or a NIR laser (808 nm, 400 mW/cm2). The absorption measurements followed by irradiation were carried out every 5 min. Light-induced in vitro PDT effect Hela cells were seeded into 24-well cell culture plates (1 × 105 cells/well) and incubated for 24 h. After learn more being treated with ZnPc4-loaded Aurod@pNIPAAm-PEGMA nanogels (300 μg/mL) in serum-free medium at 37°C for 22 h, chloroquine (10 mg/mL) was added into every well for another 2 h to promote endosomal escape [22]. Then, Hela cells were washed with PBS and incubated in a nanogel-free medium and treated with an 808-nm laser at 400 mW/cm2 for 15 min and a 680-nm

LED lamp at 10 mW/cm2 for 40 min. For cell survival test, the irradiated plates were returned to the incubator, and cell viability was colorimetrically measured 48 h later with MTT assay [23]. Results and discussion Synthesis of Aurod@pNIPAAm-PEGMA nanogel The synthesis of PEGMA-SH was shown in Figure 1. PEGMA-DTNB compound was firstly gained by the esterification reaction between the terminal hydroxyl group on the PEGMA and the carboxyl group on the DTNB with the DCC as medium and DMAP as catalyst [24, 25]. Subsequently, the disulfide bond of PEGMA-DTNB was reduced by NaBH4 to yield the desired PEGMA-SH compound. Figure 1 Schematic description of the synthesis of PEGMA-SH. The strategy to prepare the Aurod@pNIPAAm-PEGMA

nanogel involves two steps, growing a PEGMA monolayer on the surface of a AuNR, followed by in situ polymerization and cross-linking of NIPAAm and PEGMA, as depicted in Figure 2. In the first step, the AuNR surface was modified with a PEGMA self-assembled monolayer through a sulfhydryl-gold interaction. Arachidonate 15-lipoxygenase In the second step, PEGMA-modified AuNRs could be used as a template for in situ formation of hydrogel by polymerization and cross-linking of NIPAM and PEGMA with BIS as crosslinker, APS as initiator, and SDS as emulsifier. The coating of pNIPAAm-PEGMA on AuNRs can be reflected in the corresponding UV–vis spectra (Figure 3). AuNRs used in this work had a length of about 50 nm with an aspect ratio of approximately 3.2 (Figure 4A) which exhibited the maximum of the plasmon peak of 794 nm (Figure 3a). After the AuNRs were modified with pNIPAAm-PEGMA, a red shift from 794 to 801 nm occurred (Figure 3b).