An enzyme-responsive nanocontainer as an intelligent signal-amplification platform for a multiple proteases assay

Mesoporous silica nanoparticles as a drug delivery mechanism

Research in intelligent drug delivery systems within the field of biomedicine promises to enhance drug efficacy at disease sites and reduce associated side effects. Mesoporous silica nanoparticles (MSNs), characterized by their large specific surface area, appropriate pore size, and excellent biocompatibility, have garnered significant attention as one of the most effective carriers for drug delivery. The hydroxyl groups on their surface are active functional groups, facilitating easy functionalization. The installation of controllable molecular machines on the surface of mesoporous silica to construct nanovalves represents a crucial advancement in developing intelligent drug delivery systems (DDSs) and addressing the issue of premature drug release. In this review, we compile several notable and illustrative examples of MSNs and discuss their varied applications in DDSs. These applications span regulated and progressive drug release mechanisms. MSNs hold the potential to enhance drug solubility, improve drug stability, and mitigate drug toxicity, attributable to their ease of functionalization. Furthermore, intelligent hybrid nanomaterials are being developed, featuring programmable properties that react to a broad spectrum of stimuli, including light, pH, enzymes, and redox triggers, through the use of molecular and supramolecular switches.

Acetylcholinesterase-capped Mesoporous Silica Nanoparticles Controlled by the Presence of Inhibitors

Two different acetylcholinesterase (AChE)-capped mesoporous silica nanoparticles (MSNs), S1-AChE and S2-AChE, were prepared and characterized. MSNs were loaded with rhodamine B and the external surface was functionalized with either pyridostigmine derivative P1 (to yield solid S1) or neostigmine derivative P2 (to obtain S2). The final capped materials were obtained by coordinating grafted P1 or P2 with AChE's active sites (to give S1-AChE and S2-AChE, respectively). Both materials were able to release rhodamine B in the presence of diisopropylfluorophosphate (DFP) or neostigmine in a concentration-dependent manner via the competitive displacement of AChE through DFP and neostigmine coordination with the AChE's active sites. The responses of S1-AChE and S2-AChE were also tested with other enzyme inhibitors and substrates. These studies suggest that S1-AChE nanoparticles can be used for the selective detection of nerve agent simulant DFP and paraoxon.

Mesoporous silica materials for controlled delivery based on enzymes

This review summarises examples of capped mesoporous silica materials for controlled delivery that use enzymes as external triggers or functional components of the gating ensemble.

Molecular and supramolecular switches on mesoporous silica nanoparticles

This review summarizes the recent advances of molecular and supramolecular switches installed on mesoporous silica nanoparticles.

Target-responsive DNA-capped nanocontainer used for fabricating universal detector and performing logic operations

Nucleic acids have become a powerful tool in nanotechnology because of their controllable diverse conformational transitions and adaptable higher-order nanostructure. Using single-stranded DNA probes as the pore-caps for various target recognition, here we present an ultrasensitive universal electrochemical detection system based on graphene and mesoporous silica, and achieve sensitivity with all of the major classes of analytes and simultaneously realize DNA logic gate operations. The concept is based on the locking of the pores and preventing the signal-reporter molecules from escape by target-induced the conformational change of the tailored DNA caps. The coupling of 'waking up' gatekeeper with highly specific biochemical recognition is an innovative strategy for the detection of various targets, able to compete with classical methods which need expensive instrumentation and sophisticated experimental operations. The present study has introduced a new electrochemical signal amplification concept and also adds a new dimension to the function of graphene-mesoporous materials hybrids as multifunctional nanoscale logic devices. More importantly, the development of this approach would spur further advances in important areas, such as point-of-care diagnostics or detection of specific biological contaminations, and hold promise for use in field analysis.

Towards chemical communication between gated nanoparticles

The design of comparatively simple and modularly configurable artificial systems able to communicate through the exchange of chemical messengers is, to the best of our knowledge, an unexplored field. As a proof-of-concept, we present here a family of nanoparticles that have been designed to communicate with one another in a hierarchical manner. The concept involves the use of capped mesoporous silica supports in which the messenger delivered by a first type of gated nanoparticle is used to open a second type of nanoparticle, which delivers another messenger that opens a third group of gated nanoobjects. We believe that the conceptual idea that nanodevices can be designed to communicate with one another may result in novel applications and will boost further advances towards cooperative systems with complex behavior as a result of the communication between simple abiotic individual components.

DNA-mediated biomineralization of rare-earth nanoparticles for simultaneous imaging and stimuli-responsive drug delivery

A DNA-guided method for surface engineering of NaGdF4:Ce/Tb hybrid nanoparticle has been proposed. In this study, the DNA molecules that retained after one-pot NaGdF4:Ce/Tb synthesis is directly utilized as biotemplate for CaP heterogeneous nucleation, thus the dual-purpose function of DNA is realized in the current study which could afford a new type of pH-responsive theranostic platform to enhance the therapeutic efficiency while minimizing side effects. The introduction of another layer of aptamer molecules on CaP facilitated cellular uptake of the resulting nanocomposite into specific target cells via receptor-mediated endocytosis. After been taken by the target tumor cells, the NaGdF4:Ce/Tb@CaP was found to be mostly accumulated in lysosome, which facilitated the dissolving of CaP coatings as non-toxic ions to initiate drug release and efficient cancer cell destruction. We envision that the hybrid nanocarrier may serve as practical and multifunctional probe for cancer therapy and the presented synthesis approach here may also benefit the preparation of many other types of multifunctional inorganic-biomolecular hybrid nanostructures based on the DNA nanotechnology.