Minggang Zhao

3D graphene foams decorated by CuO nanoflowers for ultrasensitive ascorbic acid detection

When the in vitro research works of biosensing begin to mimic in vivo conditions, some certain three-dimensional (3D) structures of biosensors are needed to accommodate biomolecules, bacteria or even cells to resemble the in vivo 3D environment. To meet this end, a novel method of synthesizing CuO nanoflowers on the 3D graphene foam (GF) was first demonstrated. The 3DGF/CuO nanoflowers composite was used as a monolithic free-standing 3D biosensor for electrochemical detection of ascorbic acid (AA). The 3D conductive structure of the GF is favorable for current collection, mass transport and loading bioactive chemicals. And CuO nanoflowers further increase the active surface area and catalyze the redox of AA. Thus, all these features endows 3DGF/CuO composite with outstanding biosensing properties such as an ultrahigh sensitivity of 2.06 mA mM(-1) cm(-2) to AA at 3 s response time.

Controlled synthesis of spinel ZnFe2O4 decorated ZnO heterostructures as peroxidase mimetics for enhanced colorimetric biosensing

Controlled synthesis of spinel ZnFe2O4 nanoparticle-decorated ZnO nanofiber heterostructures was carried out with regularly varied particle sizes and uniform distribution. The obtained heterostructures possessed enhanced intrinsic peroxidase-like activity, and the activities regularly changed as the sizes of ZnFe2O4 nanoparticles varied. The heterostructures were further applied in sensitive colorimetric biosensing of urine glucose.

A single mesoporous ZnO/Chitosan hybrid nanostructure for a novel free nanoprobe type biosensor.

A novel method of fabricating a free probe type nanoscale biosensor is first demonstrated. A free probe type biosensor based on a single one-dimensional (1D) mesoporous ZnO/Chitosan inorganic-organic hybrid nanostructure is constructed. The as-prepared biosensor exhibited excellent biosensing performance and was stable in solution due to its inorganic-organic hybrid structure. The special mesoporous nanostructure with protuberances favors enzymes loading and enhances electrical communication efficiency. The feasibility of employing a single 1D nanostructure as a separate free nanoprobe for biosensing is demonstrated. This kind of free probe type biosensor will not only provides a new tool for micro-targets detection in microcell and enzymatic studies, but also has the potential to be inserted into single cell or other microorganism for biological studies.

Synthesis of mesoporous multiwall ZnO nanotubes by replicating silk and application for enzymatic biosensor

A facial biotemplate-directed synthetic route for fabricating mesoporous multiwall ZnO nanotubes (ZnO-MMNTs) was proposed. Owing to the mesoporous multiwall based matrix, one dimensional (1D) tubes based channels and high isoelectric point (IEP), the prepared ZnO-MMNTs are wonderful platform to immobilize glucose oxidase (GOx) for glucose biosensing. Scale-adaptive cells are constructed to hold enzymes molecules, maintain enzymatic activity and keep stability. The prepared enzymatic electrode (chitosan/GOx/ZnO/Au) exhibits high sensitivity (47.2 μA mM(-1)cm(-2)), very fast response (<2s), quite low KM(app) (1.09 mM), excellent selectivity and stability. Therefore, ZnO-MMNTs are promising material for enzyme assembly and other biological applications.

Bioinspired Formation of 3D Hierarchical CoFe2O4 Porous Microspheres for Magnetic-Controlled Drug Release

Bioinspired by the morphology of dandelion pollen grains, we successfully prepared a template-free solution-based method for the large-scale preparation of three-dimensional (3D) hierarchical CoFe2O4 porous microspheres. Besides, on the basis of the effect of the reaction time on the morphology evolution of the precursor, we proposed an in situ dissolution-recrystallization growth mechanism with morphology and phase change to understand the formation of dandelion pollenlike microspheres. Doxorubicin hydrochloride, an anticancer drug, is efficiently loaded into the CoFe2O4 microspheres. The magnetic nanoparticles as field-controlled drug carriers offer a unique power of magnetic guidance and field-triggered drug-release behavior. Therefore, 3D hierarchical CoFe2O4 porous microspheres demonstrate the great potential for drug encapsulation and controlled drug-release applications.

Highly sensitive electrochemical detection of circulating tumor DNA based on thin-layer MoS2/graphene composites

By integrating thin-layer molybdenum disulfide (MoS2) and graphene through a hydrothermal process and an ultrasonic method, a label-free, amplification-free and ultrasensitive circulating tumor DNA electrochemical sensor was made. Compared with other methods, this preparation process was simpler and the electrochemical properties were enhanced. Using a differential pulse voltammetry test, this sensor can detect trace amounts of DNA in the range from 10−16 M to 10−13 M. Compared with other methods that are used to detect the same circulating tumor DNA, this sensor has an obvious advantage in sensitivity, cost and simplicity because it removes the need for labelling processes and amplifiers.

Self-assemble ZnMn2O4 hierarchical hollow microspheres into self-supporting architecture for enhanced biosensing performance

We demonstrate a facile and scalable approach to fabricate and self-assemble the hierarchical hollow microspheres into self-supporting architecture by naturally grown branches. The supporting branches can afford integrated transport channels and significantly improve the kinetic performance and mechanical stability. Meanwhile, the supported hierarchical microspheres acting as functional cell can provide high active sites, multiple response and suitable environment for immobilizing biomolecules. Different enzymes are immobilized for biosensors. The experiments demonstrate that the effective assembly of hierarchical microspheres into large size ordered architecture by self-supporting branches can significantly enhance the biosensing performance.