Silica-Based Nanoparticles: Design and Properties - Advanced Fluorescence Reporters in Chemistry and Biology - page 246

a. Core (64 nm)
b. Core-shell (64 nm + 6 nm)
c. Core-shell (64 nm + 15 nm)
d. Core-shell (64 nm + 20 nm)

1.0

0.8

d

0.6

c

0.4

b

0.2

a

0.0

0

1 × 10 4 10 4 10 4 10 4

2 × 3 × 4 ×

Reaction time (s)

Fig. 8 Fluorescence intensities of doped TTMAPP versus metalation time. Reproduced with
permission from Ref. [ 39 ]

metal ion core doped with porphyrin shell

diffusion gradient in a nanomatrix
diffusion gradient in a bulk solution

Fig. 9 A schematic diagram of the diffusion-controlled porphyrin metalation in a small nanoma-
trix ( left ) and a larger nanomatrix ( right ). Reproduced with permission from Ref. [ 39 ]

The reaction kinetic study suggested that dye molecules in DDSNs have limited
reaction activity although they are accessible to outside species. If highly reactive
dye molecules are desirable in DDSNs, less dense silica nanomatrixes should be
considered, such as mesoporous nanostructures.

3.7 Toxicity of DDSNs

Toxicity of DDSNs is a critical concern for their applications in biological samples.
The toxicity of DDSNs depends on size, surface modification, and dye molecule