Facile fabrication of glutathione-responsive and photothermal nanocarriers with dendritic mesoporous silica nanoparticles for the controlled drug delivery

Albumin Hydrogel–Coated Mesoporous Silica Nanoparticle as a Carrier of Cationic Porphyrin and Ratiometric Fluorescence pH Sensor

“…The linear pH range of F-BSA/MSN/TMPyP (6.1–8.9) includes pH of normal tissues (∼7.4), tumor tissues (∼6.8), and cancer cells inside (>7.4). , When HeLa cells were incubated with F-BSA/MSN/TMPyP (≤250 μg mL –1 ), the cell viability was above 95%. The observed cytotoxicity of F-BSA/MSN/TMPyP was comparable to other BSA-coated MSN nanocarrier systems. − We therefore consider that F-BSA/MSN/TMPyP has potential use in endoscopic cancer diagnostics and PDT.…”

“…In BSA-coated MSN nanocarrier systems, cytotoxicity of the nanocarrier was reported to be negligible when the concentration of nanocarrier was 100–200 μg mL –1 . − As shown in Figure G, the viability of HeLa cells was above 95% when the concentration of F-BSA/MSN/TMPyP was below 250 μg mL –1 . The cytotoxicity of MSN coated with the BSA hydrogel layer was thus comparable to those for the BSA-coated MSN, indicating that the coating of the BSA hydrogel shell layer is a useful method to synthesize the MSN-based nanocarrier system.…”

“…The F-BSA hydrogel shell layer acted not as a gate layer but as a support layer that mediates diffusion of TMPyP from the MSN pore interior into the solution phase. The monolayer of folded BSA on the MSN is commonly used as a gate layer for pH-, GSH-, and protease-responsive drug release systems. − Since the molecular size of folded BSA (14 nm × 4 nm) is larger than the MSN pore diameter (∼2 nm), the folded BSA may work as a gatekeeper to block the MSN pore channels. In contrast to the monolayer of folded BSA, the F-BSA hydrogel layer has small cavities that permit diffusion of TMPyP because it is formed through the assembly of denatured F-BSA molecules.…”

“…The folded BSA is a typical gatekeeper because its molecular size (14 nm × 4 nm) is larger than the MSN pore diameter (∼2 nm). The BSA-coated MSN nanocarrier is usually synthesized by immobilizing folded BSA on MSN via disulfide bonds, and its controlled drug release behavior relies on detachment and degradation of the surface BSA by inner stimuli such as reducing reagents and pH variations. − On the other hand, the F-BSA hydrogel layer formed by self-assembly of denatured F-BSA is not gatekeeper and its roll for the TMPyP release is to mediate the diffusion of TMPyP from the MSN pore interior into the solution phase. The TMPyP release from F-BSA/MSN/TMPyP is insensitive to the inner stimuli.…”

“…The total charge of BSA (pI = 4.7) is negative under physiological conditions. The BSA monomer readily adsorbs onto the negatively charged silica surfaces, − and its desorption depends on the solution conditions. − It has hence been covalently immobilized on the surface of MSN functionalized with anchor molecules. − On the other hand, adsorption of denaturated BSA was reported to improve the density and stability of physisorbed BSA molecules on a silica surface. − In this study, we aimed at forming a BSA hydrogel by thermal gelation of denatured BSA molecules preconcentrated at the external surface of the MSN (Figure A). Since its structure is maintained by various covalent disulfide bonds and noncovalent (hydrogen bonds, hydrophobic interaction, and complexation with cations) interactions, − the BSA hydrogel is expected to be chemically and thermally stable.…”