Metal‐organic frameworks (MOFs) with attractive properties such as high surface area, tunable porosity, designable functionality and excellent stability, have aroused great interest from researchers as the matrices for enzyme immobilization. Recently, several efficient strategies including surface immobilization, post‐synthetic infiltration and in situ encapsulation have been explored. MOF‐immobilized enzymes, named enzymes@MOFs, show remarkably enhanced stability and recyclability, accelerating cell‐free biocatalysis in diverse applications. This concept will impart the typical strategies for enzyme immobilization with MOFs, and their potential applications.
In
the past decade, scientists sought to engineer nanomaterials
with natural enzymes-like biological function, and searched for newfangled
applications. Herein, we show the first example of utilizing a bimetal
metal–organic framework (MOF-818) platform for mimicking of
Cu/Zn-superoxide dismutase (Cu/Zn-SOD), an important antioxidant enzyme
that specifically scavenges superoxide anions. Experimental data and
theoretical calculations reveal that the high Cu/Zn-SOD-like activity
of MOF-818 results from the bimetal synergistic catalysis, which is
analogous to natural Cu/Zn-SOD. Such a bimetal biomimetic process
allows for MOF-818 with much higher SOD-like activity, compared to
the reported monometallic MOFs mimics. Moreover, the SOD-like MOF-818
displays excellent stability against heating, organic solvents, and
denaturant treatments, which should inactivate natural enzymes. Based
on the catalytic mechanism, we also construct a MOF-818-based colorimetric
sensing platform for phosphorylated peptides and proteins detection.
This work provides a new insight for biomimetic engineering, and may
expedite the scale-up applications of SOD-like nanozymes in various
fields.
Nanozymes are of particular interest due to their enzyme-mimicking activity and high stability that are favorable in biomedical sensing and immunoassays. In this work, we report a highly specific N-doped nanozyme through pyrolysis of framework-confined bovine serum albumin (BSA). This strategy allows one to translate the low-cost and featureless BSA into a highly active enzyme mimic. The obtained carbon nanozyme (denoted as HBF-1-C800) displays 3-to 7-fold enhancement on peroxidase (POD) activity compared with the conventional carbon nanozymes and also shows ca. 5-fold activity enhancement compared to the reported N-doping graphene. Such excellent POD activity originates from high N-doping efficiency, protein-induced defective sites, and the intrinsic porous structure of HBF-1-C800, which provides abundantly accessible active sites and accelerates substrate diffusion simultaneously. Importantly, the HBF-1-C800 nanozyme has highly specific POD activity and also enables resistance to several harsh conditions that should denature natural enzymes. These features allow it with high accuracy, stability, and sensitivity for biosensing applications. Moreover, HBF-1-C800 has been designed as a promising platform for colorimetric biosensing of several biomarkers including H 2 O 2 , glutathione, and glucose, with wide linear ranges and low limits of detection that are satisfied with the disease diagnosis.
Metal–organic
frameworks (MOFs) have become a promising
accommodation for enzyme immobilization and protection. However, the
integration of multienzymes into MOFs may result in compromise of
individual enzymatic activity. In this work, we report an iron mineralization
strategy to facilely construct a mesoporous MOF, possessing excellent
peroxidase-mimic bioactivity. Furthermore, the feasibility of in situ
encapsulating natural enzymes within the developed mesoporous MOF
nanozymes endows these natural/nanomimic enzyme hybrids with remarkably
enhanced synergistic catalysis ability. Such activity enhancement
is mainly due to (1) the fast flux rate of substances through the
interconnected mesoporous channels and (2) the simultaneously increased
loading amount of enzymes and iron within the MOFs caused by the iron
mineralization process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.