Youhui Lin

Incorporating Graphene Oxide and Gold Nanoclusters: A Synergistic Catalyst with Surprisingly High Peroxidase-Like Activity Over a Broad pH Range and its Application for Cancer Cell Detection

A synergistic graphene oxide-gold nanocluster (GO-AuNC) hybrid has been constructed as an enzyme mimic that is able to show high catalytic activity over a broad pH range, especially at neutral pH. Importantly, the target-functionalized hybrid has been applied as a robust nanoprobe for selective, quantitative, and fast colorimetric detection of cancer cells.

A dual fluorometric and colorimetric sensor for dopamine based on BSA-stabilized Au nanoclusters

An easy prepared fluorometric and colorimetric dual channel probe is developed for dopamine (DA) detection with high sensitivity and selectivity by use of BSA-stabilized Au nanoclusters (BSA-AuNCs). The BSA-AuNCs exhibit strong fluorescence emission, while upon addition of DA, the AuNCs show a dramatic decrease of the fluorescence intensity as a result of the photo-induced electron transfer process from the electrostatically attached DA to the BSA-AuNCs. The detection limit of DA can be as low as 10 nM. In addition, the assay for DA can also be easy to implement for visual detection due to the observed inhibition of the peroxidase-like activity of AuNCs in the presence of DA, with a detection limit of 10 nM. Both fluorometric and colorimetric methods exhibit excellent selectivity toward DA over interfering substances. Furthermore, we demonstrate the application of the present approach in hydrochloride injection sample, human serum sample and PC12 cells, which suggests its great potential for diagnostic purposes.

Bioresponsive Hyaluronic Acid-Capped Mesoporous Silica Nanoparticles for Targeted Drug Delivery

In this paper, we present a facile strategy to synthesize hyaluronic acid (HA) conjugated mesoporous silica nanoparticles (MSP) for targeted enzyme responsive drug delivery, in which the anchored HA polysaccharides not only act as capping agents but also as targeting ligands without the need of additional modification. The nanoconjugates possess many attractive features including chemical simplicity, high colloidal stability, good biocompatibility, cell-targeting ability, and precise cargo release, making them promising agents for biomedical applications. As a proof-of-concept demonstration, the nanoconjugates are shown to release cargoes from the interior pores of MSPs upon HA degradation in response to hyaluronidase-1 (Hyal-1). Moreover, after receptor-mediated endocytosis into cancer cells, the anchored HA was degraded into small fragments, facilitating the release of drugs to kill the cancer cells. Overall, we envision that this system might open the door to a new generation of carrier system for site-selective, controlled-release delivery of anticancer drugs.

Mesoporous silica-encapsulated gold nanoparticles as artificial enzymes for self-activated cascade catalysis

A significant challenge in chemistry is to create synthetic structures that mimic the complexity and function of natural systems. Here, a self-activated, enzyme-mimetic catalytic cascade has been realized by utilizing expanded mesoporous silica-encapsulated gold nanoparticles (EMSN-AuNPs) as both glucose oxidase- and peroxidase-like artificial enzymes. Specifically, EMSN helps the formation of a high degree of very small and well-dispersed AuNPs, which exhibit an extraordinarily stability and dual enzyme-like activities. Inspired by these unique and attractive properties, we further piece them together into a self-organized artificial cascade reaction, which is usually completed by the oxidase-peroxidase coupled enzyme system. Our finding may pave the way to use matrix as the structural component for the design and development of biomimetic catalysts and to apply enzyme mimics for realizing higher functions.

Biomineralization inspired surface engineering of nanocarriers for pH-responsive, targeted drug delivery

Recent insight into the molecular mechanisms of natural biomineralization has enabled biomimetic synthesis of functional organic-inorganic hybrid materials under mild reaction conditions. Here, we describe a novel method to construct organic-inorganic hybrid on mesoporous silica nanoparticles by utilizing electrostatically absorbed hyaluronic acid (HA) as a reaction site for deposition of calcium phosphate (CaP) minerals. The addition of another layer of HA on the CaP surfaces not only stabilizes the nanocomposites but also confers target ability toward CD44 overexpressed cancer cells. The nanomaterials enable controlled release of loaded anticancer drugs in acidic subcellular environments after receptor mediated endocytosis. More importantly, our study demonstrated that the cancer targeting nanomaterials dramatically enhanced cellular uptake and cytotoxicity toward breast carcinoma cells. These results thus open new opportunities for biomineralization guided nanostructure assemblies with great potential for biomedical applications.

Ionic Liquid as an Efficient Modulator on Artificial Enzyme System: Toward the Realization of High-Temperature Catalytic Reactions

Herein, with the aid of ionic liquid, we demonstrate for the first time that highly stable Au/SiO2 hetero-nanocomposites can serve as a robust and recyclable peroxidase mimic for realizing high-temperature catalytic reactions. Our findings pave the way to use nanomaterials for the design and development of efficient biomimetic catalysts and, more significantly, to apply ionic liquid as a positive modulator in catalytic reactions.

Nanoceria-Triggered Synergetic Drug Release Based on CeO2-Capped Mesoporous Silica Host-Guest Interactions and Switchable Enzymatic Activity and Cellular Effects of CeO2

Herein, a pH stimuli-responsive vehicle for intracellular drug delivery using CeO2 capped mesoporous silica nanoparticles (MSN) is reported. β-Cyclodextrin-modified CeO2 nanoparticles could cap onto ferrocene-functionalized mesoporous silica through host-guest interactions. After internalization into A549 cells by a lysosomal pathway, the ferrocenyl moieties are oxidized to ferrocenium ions by CeO2 lids, which could trigger the uncapping of the CeO2 and cause the drugs release. Because of the pH-dependent toxicity, the CeO2 here behaves as a multi-purpose entity that not only acts as a lid but also exhibits a synergistic antitumor effect on cancer cells. Meanwhile, the cell protective effect of CeO2 nanoparticles alone is demonstrated, which ensures that the dissolved CeO2 nanoparticles can be non-toxic to normal cells.

Artificial DNA nano-spring powered by protons.

A novel multifunctional, proton-fueled DNA nano-spring has been constructed. By incorporation of the G-quadruplex/i-motif sequence into the assembly, the nanodevice can perform springlike motions in response to changes in the environmental pH without permanent deformation. Nanosized objects/functional groups could be assembled/disassembled into this system in an addressable, contractile, and reversible manner.

Exonuclease-aided amplification for label-free and fluorescence turn-on DNA detection based on aggregation-induced quenching

A facile, universal and label-free fluorescence turn-on amplification strategy for the detection of DNA has been reported, which can achieve ultralow femtomolar detection of a target gene sequence with high selectivity.

Using Thermally Regenerable Cerium Oxide Nanoparticles in Biocomputing to Perform Label-free, Resettable, and Colorimetric Logic Operations†

A label-free, resettable, and colorimetric logic network has been realized by utilizing thermally regenerable cerium oxide nanoparticles and biocatalytic reactions. Coupling switchable CeO(2) nanoparticles with biocomputing would convert molecular recognition events into colorimetric outputs and make logic gates feasible to reset.