Nanoscale porphyrinic metal–organic
frameworks (NMOFs) have emerged as promising therapeutic platforms
for the photodynamic therapy (PDT) of cancer in recent years. However,
the relatively large sizes of current NMOFs ranging from tens to hundreds
of nanometers usually lead to inefficient body clearance and unsatisfactory
PDT effect, thus amplifying their long-term toxicity and restricting
their further usage. To overcome these shortcomings, herein, ultrasmall
porphyrinic metal–organic framework nanodots (MOF QDs) prepared
from NMOFs are rationally synthesized via a facile
method and used as renal-clearable nanoagents for the enhanced PDT
of cancer. Compared with the precursor NMOFs, our well-prepared MOF
QDs can generate 2-fold effective toxic reactive oxygen species (ROS)
upon the same light irradiation and greatly decrease the inefficacy
of PDT caused by the inefficient use of ROS generated from the interior
of NMOFs. Meanwhile, the IC50 value of ultrasmall MOF QDs
is nearly one-third that of NMOFs, and in vivo results
demonstrate that our MOF QDs exhibit better PDT efficacy than NMOFs
under the same treatment owing to their overcoming the limited ROS
diffusion distance. Significantly, these ultrasmall MOF QDs show efficient
tumor accumulation and rapid renal clearance in vivo, indicating their potential in biomedical utility. Last but not
least, comprehensive investigations of long-term toxicity of these
MOF QDs well demonstrate their overall safety. Therefore, this study
will offer valuable insight into the development of safe and high-performance
PDT nanoplatforms for further clinical translation.
Significant progress is achieved for the utilization of graphene quantum dots as enzyme mimics in various biomedical fields recently. Although promising, the biocatalytic performance is far from satisfactory. Here, the rational design and synthesis of specific oxygenated groups enriched graphene quantum dots (o-GQDs) via a facile oxidation reflux route is reported. These well-prepared o-GQDs with uniform size exhibit an ultrahigh peroxidase-like activity in a wide range of pH values, and their superior performance is verified by using glucose detection as a typical model. Compared with classical nanozymes, these o-GQDs show multiple times higher enzymatic activity. It is believed that the super facile synthesis strategy can greatly facilitate the practical use of o-GQDs as enzyme mimics in the future.
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