pH/redox/UV irradiation multi-stimuli responsive nanogels from star copolymer micelles and Fe3+ complexation for “on-demand” anticancer drug delivery

Single-, Dual-, and Multi-Stimuli-Responsive Nanogels for Biomedical Applications

In recent years, stimuli-responsive nanogels that can undergo suitable transitions under endogenous (e.g., pH, enzymes and reduction) or exogenous stimuli (e.g., temperature, light, and magnetic fields) for on-demand drug delivery, have received significant interest in biomedical fields, including drug delivery, tissue engineering, wound healing, and gene therapy due to their unique environment-sensitive properties. Furthermore, these nanogels have become very popular due to some of their special properties such as good hydrophilicity, high drug loading efficiency, flexibility, and excellent biocompatibility and biodegradability. In this article, the authors discuss current developments in the synthesis, properties, and biomedical applications of stimulus-responsive nanogels. In addition, the opportunities and challenges of nanogels for biomedical applications are also briefly predicted.

Polymeric Micellar Systems-A Special Emphasis on "Smart" Drug Delivery

Concurrent developments in anticancer nanotechnological treatments have been observed as the burden of cancer increases every year. The 21st century has seen a transformation in the study of medicine thanks to the advancement in the field of material science and nanomedicine. Improved drug delivery systems with proven efficacy and fewer side effects have been made possible. Nanoformulations with varied functions are being created using lipids, polymers, and inorganic and peptide-based nanomedicines. Therefore, thorough knowledge of these intelligent nanomedicines is crucial for developing very promising drug delivery systems. Polymeric micelles are often simple to make and have high solubilization characteristics; as a result, they seem to be a promising alternative to other nanosystems. Even though recent studies have provided an overview of polymeric micelles, here we included a discussion on the "intelligent" drug delivery from these systems. We also summarized the state-of-the-art and the most recent developments of polymeric micellar systems with respect to cancer treatments. Additionally, we gave significant attention to the clinical translation potential of polymeric micellar systems in the treatment of various cancers.

Carbon Quantum Dot/Chitosan-Derived Hydrogels with Photo-stress-pH Multiresponsiveness for Wearable Sensors

In recent years, hydrogels have attracted extensive attention in smart sensing owing to their biocompatibility and high elasticity. However, it is still a challenge to develop hydrogels with excellent multiple responsiveness for smart wearable sensors. In this paper, a facile synthesis of carbon quantum dots (CQDs)-doped cross-linked chitosan quaternary/carboxymethylcellulose hydrogels (CCCDs) is presented. Designing of dual network hydrogels decorated with CQDs provides abundant crosslinking and improves the mechanical properties of the hydrogels. The hydrogel-based strain sensor exhibits excellent sensitivity (gauge factor: 9.88), linearity (R² : 0.97), stretchable ability (stress: 0.67 MPa; strain: 404%), good cyclicity, and durability. The luminescent properties are endowed by the CQDs further broaden the application of hydrogels for realizing flexible electronics. More interestingly, the strain sensor based on CCCDs hydrogel demonstrates photo responsiveness (ΔR/R₀ ≈20%) and pH responsiveness (pH range ≈4-7) performance. CCCDs hydrogels can be used for gesture recognition and light sensing switch. As a proof-of-concept, a smart wearable sensor is designed for monitoring human activities and detecting pH variation in human sweat during exercise. This study reveals new possibilities for further applications in wearable health monitoring.

Polymeric micelles and cancer therapy: an ingenious multimodal tumor-targeted drug delivery system

Since the beginning of pharmaceutical research, drug delivery methods have been an integral part of it. Polymeric micelles (PMs) have emerged as multifunctional nanoparticles in the current technological era of nanocarriers, and they have shown promise in a range of scientific fields. They can alter the release profile of integrated pharmacological substances and concentrate them in the target zone due to their improved permeability and retention, making them more suitable for poorly soluble medicines. With their ability to deliver poorly soluble chemotherapeutic drugs, PMs have garnered considerable interest in cancer. As a result of their remarkable biocompatibility, improved permeability, and minimal toxicity to healthy cells, while also their capacity to solubilize a wide range of drugs in their micellar core, PMs are expected to be a successful treatment option for cancer therapy in the future. Their nano-size enables them to accumulate in the tumor microenvironment (TME) via the enhanced permeability and retention (EPR) effect. In this review, our major aim is to focus primarily on the stellar applications of PMs in the field of cancer therapeutics along with its mechanism of action and its latest advancements in drug and gene delivery (DNA/siRNA) for cancer, using various therapeutic strategies such as crossing blood-brain barrier, gene therapy, photothermal therapy (PTT), and immunotherapy. Furthermore, PMs can be employed as "smart drug carriers," allowing them to target specific cancer sites using a variety of stimuli (endogenous and exogenous), which improve the specificity and efficacy of micelle-based targeted drug delivery. All the many types of stimulants, as well as how the complex of PM and various anticancer drugs react to it, and their pharmacodynamics are also reviewed here. In conclusion, commercializing engineered micelle nanoparticles (MNPs) for application in therapy and imaging can be considered as a potential approach to improve the therapeutic index of anticancer drugs. Furthermore, PM has stimulated intense interest in research and clinical practice, and in light of this, we have also highlighted a few PMs that have previously been approved for therapeutic use, while the majority are still being studied in clinical trials for various cancer therapies.

Progress in Polymeric Micelles for Drug Delivery Applications

Polymeric micelles (PMs) have made significant progress in drug delivery applications. A robust core-shell structure, kinetic stability and the inherent ability to solubilize hydrophobic drugs are the highlights of PMs. This review presents the recent advances and understandings of PMs with a focus on the latest drug delivery applications. The types, methods of preparation and characterization of PMs are described along with their applications in oral, parenteral, transdermal, intranasal and other drug delivery systems. The applications of PMs for tumor-targeted delivery have been provided special attention. The safety, quality and stability of PMs in relation to drug delivery are also provided. In addition, advanced polymeric systems and special PMs are also reviewed. The in vitro and in vivo stability assessment of PMs and recent understandings in this area are provided. The patented PMs and clinical trials on PMs for drug delivery applications are considered indicators of their tremendous future applications. Overall, PMs can help overcome many unresolved issues in drug delivery.

Comprehensive review on ultrasound-responsive theranostic nanomaterials: mechanisms, structures and medical applications

The field of theranostics has been rapidly growing in recent years and nanotechnology has played a major role in this growth. Nanomaterials can be constructed to respond to a variety of different stimuli which can be internal (enzyme activity, redox potential, pH changes, temperature changes) or external (light, heat, magnetic fields, ultrasound). Theranostic nanomaterials can respond by producing an imaging signal and/or a therapeutic effect, which frequently involves cell death. Since ultrasound (US) is already well established as a clinical imaging modality, it is attractive to combine it with rationally designed nanoparticles for theranostics. The mechanisms of US interactions include cavitation microbubbles (MBs), acoustic droplet vaporization, acoustic radiation force, localized thermal effects, reactive oxygen species generation, sonoluminescence, and sonoporation. These effects can result in the release of encapsulated drugs or genes at the site of interest as well as cell death and considerable image enhancement. The present review discusses US-responsive theranostic nanomaterials under the following categories: MBs, micelles, liposomes (conventional and echogenic), niosomes, nanoemulsions, polymeric nanoparticles, chitosan nanocapsules, dendrimers, hydrogels, nanogels, gold nanoparticles, titania nanostructures, carbon nanostructures, mesoporous silica nanoparticles, fuel-free nano/micromotors.

Smart Nanomaterials for Biomedical Applications-A Review

Recent advances in nanotechnology have forced the obtaining of new materials with multiple functionalities. Due to their reduced dimensions, nanomaterials exhibit outstanding physio-chemical functionalities: increased absorption and reactivity, higher surface area, molar extinction coefficients, tunable plasmonic properties, quantum effects, and magnetic and photo properties. However, in the biomedical field, it is still difficult to use tools made of nanomaterials for better therapeutics due to their limitations (including non-biocompatible, poor photostabilities, low targeting capacity, rapid renal clearance, side effects on other organs, insufficient cellular uptake, and small blood retention), so other types with controlled abilities must be developed, called "smart" nanomaterials. In this context, the modern scientific community developed a kind of nanomaterial which undergoes large reversible changes in its physical, chemical, or biological properties as a consequence of small environmental variations. This systematic mini-review is intended to provide an overview of the newest research on nanosized materials responding to various stimuli, including their up-to-date application in the biomedical field.

pH-Sensitive nanogels for drug delivery in cancer therapy

Compared to normal tissue, solid tumors exhibit a lower pH value. Such pH gradient can be used to design pH-sensitive nanogels for selective drug delivery. The acid-sensitive elements in the nanogel cause it to swell/degrade rapidly, followed by rapid drug release.

Doxorubicin-loaded composite nanogels for cancer treatment

Nanogels as a versatile vehicle for doxorubicin have attracted great attention during the last decade. Since a nanogel composite device transport encapsulated drugs to the site of action and release them in a desirable time-frame, it could provide higher therapeutic effect. By implementation of different polymers, polymer/inorganic NPs and various crosslinking chemistry, it is possible to fabricate novel composite nanogel systems with favorable characteristics such as smart intelligent systems or multipurpose platforms. Due to high stability, good drug loading capacity for hydrophobic and hydrophilic agents, nanogels introduce great opportunity in pharmaceutical innovations. Composite nanogels show capability in gene, drug and diagnostic agents' delivery while providing an ideal platform for theranostic purposes as multifunctional systems. Doxorubicin as an anticancer agent is widely used against numerous cancers. Due to high systemic toxicity of doxorubicin, there is still need for its safe and specific delivery to the site of action. In this regard, so many efforts have been put in by the researchers for preparation of different nanogel formulations of doxorubicin in order to produce more efficient formulations. This review focuses on design, fabrication, advantages and disadvantages of composite nanogel-based doxorubicin formulations.