Stimuli-responsive Controlled Release Systems Research Articles

Recent advances in stimuli-responsive controlled release systems for neuromodulation

Neuromodulation aims to modulate the signaling activity of neurons or neural networks by the precise delivery of electrical stimuli or chemical agents and is crucial for understanding brain function and...

Carboxymethyl β-cyclodextrin grafted hollow copper sulfide@mesoporous silica carriers for stimuli-responsive pesticide delivery

Stimuli-responsive controlled release systems have received extensive attention to improve the pesticide bioavailability and minimize environmental pollution. Herein, a multiple stimuli-responsive IMI@HCuS@mSiO2 @ -ss-CβCD delivery system was constructed using modified carboxymethyl β-cyclodextrin (CβCD-ss-COOH) as sealing materials, hollow copper sulfide nanoparticles with amino-functionalized mesoporous silica shell (HCuS@mSiO2-NH2) as carriers and imidacloprid (IMI) as the model drug. The cavity structure of HCuS@mSiO2-NH2 would provide a large space for pesticide loading. The results revealed that HCuS@mSiO2-ss-CβCD was approximately 230 nm in size and the loading efficiency for IMI was 25.7%, and exhibited better biosafety on bacteria and seed. HCuS carriers were also served as photothermal agent and possessed high photothermal conversion effect (η = 38.4%). IMI@HCuS@mSiO2 @ -ss-CβCD displayed excellent foliage adhesion and multiple stimuli-responsive release properties to pH, α-amylase, GSH, and NIR. The photostability of IMI embedded in CuS@mSiO2 @ -ss-CβCD was approximately 10 times that of IMI solution. This work provides an efficient nanoplatform for realizing pesticide delivery.

Remotely controlled opening of delivery vehicles and release of cargo by external triggers.

Tremendous efforts have been devoted to the development of future nanomedicines that can be specifically designed to incorporate responsive elements that undergo modification in structural properties upon external triggers. One potential use of such stimuli-responsive materials is to release encapsulated cargo upon excitation by an external trigger. Today, such stimuli-response materials allow for spatial and temporal tunability, which enables the controlled delivery of compounds in a specific and dose-dependent manner. This potentially is of great interest for medicine (e.g. allowing for remotely controlled drug delivery to cells, etc.). Among the different external exogenous and endogenous stimuli used to control the desired release, light and magnetic fields offer interesting possibilities, allowing defined, real time control of intracellular releases. In this review we highlight the use of stimuli-responsive controlled release systems that are able to respond to light and magnetic field triggers for controlling the release of encapsulated cargo inside cells. We discuss established approaches and technologies and describe prominent examples. Special attention is devoted towards polymer capsules and polymer vesicles as containers for encapsulated cargo molecules. The advantages and disadvantages of this methodology in both, in vitro and in vivo models are discussed. An overview of challenges associate with the successful translation of those stimuli-responsive materials towards future applications in the direction of potential clinical use is given.

Microencapsulation and Stimuli-Responsive Controlled Release of Particles Using Water-in-Air Powders.

In this work, we report a facile, one-step method to encapsulate hydrophilic particles (HP) (micro- or nanosize) using water-in-air powders. Hydrophobic silica nanoparticles were mixed with an aqueous phase containing HP in the presence of air under high shear, resulting in the self-assembly of silica nanoparticles on water droplets to make water-in-air powders with HP encapsulated in the aqueous phase within the silica shell. The encapsulated HP can be released on the basis of an external stimulus such as adding an external aqueous phase of a certain pH or a surfactant solution that alters the wettability of the encapsulating silica nanoparticles. A contact angle study was performed using surface-hydrophobized glass slides, which acted as a proxy for hydrophobic silica nanoparticles, to investigate the effect of these stimuli on surface hydrophobicity. Such encapsulation and a stimuli-responsive controlled release system has promising potential in subsurface petroleum engineering such as the delayed swelling of particles for conformance control and delayed acid stimulation.

Mesoporous silica nanoparticles for stimuli-responsive controlled drug delivery: advances, challenges, and outlook.

With the development of nanotechnology, the application of nanomaterials in the field of drug delivery has attracted much attention in the past decades. Mesoporous silica nanoparticles as promising drug nanocarriers have become a new area of interest in recent years due to their unique properties and capabilities to efficiently entrap cargo molecules. This review describes the latest advances on the application of mesoporous silica nanoparticles in drug delivery. In particular, we focus on the stimuli-responsive controlled release systems that are able to respond to intracellular environmental changes, such as pH, ATP, GSH, enzyme, glucose, and H2O2. Moreover, drug delivery induced by exogenous stimuli including temperature, light, magnetic field, ultrasound, and electricity is also summarized. These advanced technologies demonstrate current challenges, and provide a bright future for precision diagnosis and treatment.

Enzyme and voltage stimuli-responsive controlled release system based on β-cyclodextrin-capped mesoporous silica nanoparticles.

Enzyme and voltage stimuli are more biologically compatible in the field of stimuli-responsive systems and release systems based on β-cyclodextrin (CD) and ferrocene (Fc) have attracted much attention. Herein, mesoporous silica nanoparticles (MSNs) have been functionalized with the ferrocenyl moiety (Fc) which interacts with β-cyclodextrin (β-CD) to form an inclusion complex on the opening of the pores. The size of the inclusion complex results in a barrier to the opening of the pores. Based on these characteristics, MSNs with nanovalves have been developed as a release system. The release system shows a clear response to heme protein (horseradish peroxidase or hemoglobin) and H2O2, glucose oxidase (GOD) with horseradish peroxidase (HRP) and glucose, or +1.5 V based on an oxidation stimulus mechanism. Modulating the amount of enzyme or the discretion of the voltage makes the release system a controlled one.

ChemInform Abstract: Functionalized Mesoporous Silica Materials for Controlled Drug Delivery

AbstractReview: 246 refs.

Functionalized mesoporous silica materials for controlled drug delivery

In the past decade, non-invasive and biocompatible mesoporous silica materials as efficient drug delivery systems have attracted special attention. Great progress in structure control and functionalization (magnetism and luminescence) design has been achieved for biotechnological and biomedical applications. This review highlights the most recent research progress on silica-based controlled drug delivery systems, including: (i) pure mesoporous silica sustained-release systems, (ii) magnetism and/or luminescence functionalized mesoporous silica systems which integrate targeting and tracking abilities of drug molecules, and (iii) stimuli-responsive controlled release systems which are able to respond to environmental changes, such as pH, redox potential, temperature, photoirradiation, and biomolecules. Although encouraging and potential developments have been achieved, design and mass production of novel multifunctional carriers, some practical biological application, such as biodistribution, the acute and chronic toxicities, long-term stability, circulation properties and targeting efficacy in vivo are still challenging.

Stimuli-responsive controlled-release system using quadruplex DNA-capped silica nanocontainers

A novel proton-fueled molecular gate-like delivery system has been constructed for controlled cargo release using i-motif quadruplex DNA as caps onto pore outlets of mesoporous silica nanoparticles. Start from simple conformation changes, the i-motif DNA cap can open and close the pore system in smart response to pH stimulus. Importantly, the opening/closing and delivery protocol is highly reversible and a partial cargo delivery can be easily controlled at will. A pH-switchable nanoreactor has also been developed to validate the potential of our system for on-demand molecular transport. This proof of concept might open the door to a new generation of carrier materials and could also provide a general route to use other functional nucleic acids/peptide nucleic acids as capping agents in the fields of versatile controlled delivery nanodevices.

Capped mesoporous silica nanoparticles as stimuli-responsive controlled release systems for intracellular drug/gene delivery

Importance of the field: The incorporation of stimuli-responsive properties into nanostructured systems has recently attracted significant attention in the research of intracellular drug/gene delivery. In particular, numerous surface-functionalized, end-capped mesoporous silica nanoparticle (MSN) materials have been designed as efficient stimuli-responsive controlled release systems with the advantageous ‘zero premature release’ property.Areas covered in this review: Herein, the most recent research progress on the design of biocompatible, capped MSN materials for stimuli-responsive intracellular controlled release of therapeutics and genes is reviewed. A series of hard and soft caps for drug encapsulation and a variety of internal and external stimuli for controlled release of different cargoes are summarized. Recent investigations on the biocompatibility of MSN both in vitro and in vivo are also discussed.What the reader will gain: The reader will gain an understanding of the challenges for the future exploration of biocompatible stimuli-responsive MSN devices.Take home message: With a better understanding of the unique features of capped MSN and its behaviors in biological environment, these multifunctional materials will find a wide variety of applications in the field of drug/gene delivery.