Light-Responsive Nanoparticles for Highly Efficient Cytoplasmic Delivery of Anticancer Agents

Unveiling green synthesis and biomedical theranostic paradigms of selenium Nanoparticles (SeNPs)- A State-of-the-Art comprehensive update

The advancements in nanotechnology, pharmaceutical sciences, and healthcare are propelling the field of theranostics, which combines therapy and diagnostics, to new heights; emphasizing the emergence of selenium nanoparticles (SeNPs) as versatile theranostic agents. This comprehensive update offers a holistic perspective on recent developments in the synthesis and theranostic applications of SeNPs, underscoring their growing importance in nanotechnology and healthcare. SeNPs have shown significant potential in multiple domains, including antioxidant, anti-inflammatory, anticancer, antimicrobial, antidiabetic, wound healing, and cytoprotective therapies. The review highlights the adaptability and biocompatibility of SeNPs, which are crucial for advanced disease detection, monitoring, and personalized treatment. Special emphasis is placed on advancements in green synthesis techniques, underscoring their eco-friendly and cost-effective benefits in biosensing, diagnostics, and imaging applications. Additionally, the appraisal scrutinizes the progressive trends in smart stimuli-responsive SeNPs, conferring their role in innovative solutions for disease management and diagnostics. Despite their promising therapeutic and prophylactic potential, SeNPs also present several challenges, particularly regarding toxicity concerns. These challenges and their implications for clinical translation are thoroughly explored, providing a balanced view of the current state and prospects of SeNPs in theranostic applications.

Reversal of Chemoresistance via Staged Liberation of Chemodrug and siRNA in Hierarchical Response to ROS Gradient

P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) often leads to the failure of antitumor chemotherapy, and codelivery of chemodrug with P-gp siRNA (siP-gp) represents a promising approach for treating chemoresistant tumors. To maximize the antitumor efficacy, it is desired that the chemodrug be latently released upon completion of siP-gp-mediated gene silencing, which however, largely remains an unmet demand. Herein, core-shell nanocomplexes (NCs) are developed to overcome MDR via staged liberation of siP-gp and chemodrug (doxorubicin, Dox) in hierarchical response to reactive oxygen species (ROS) concentration gradients. The NCs are constructed from mesoporous silica nanoparticles (MSNs) surface-decorated with cRGD-modified, PEGylated, ditellurium-crosslinked polyethylenimine (RPPT), wherein thioketal-linked dimeric doxorubicin (TK-Dox2) and photosensitizer are coencapsulated inside MSNs while siP-gp is embedded in the RPPT polymeric layer. RPPT with ultrahigh ROS-sensitivity can be efficiently degraded by the low-concentration ROS inside cancer cells to trigger siP-gp release. Upon siP-gp-mediated gene silencing and MDR reversal, light irradiation is performed to generate high-concentration, lethal amount of ROS, which cleaves thioketal with low ROS-sensitivity to liberate the monomeric Dox. Such a latent release profile greatly enhances Dox accumulation in Dox-resistant cancer cells (MCF-7/ADR) in vitro and in vivo, which cooperates with the generated ROS to efficiently eradicate MCF-7/ADR xenograft tumors.

Polydopamine nanoplatform with near infrared light and pH dual stimuli-responsive for chemo-photothermal cancer therapy

Photothermal agent accompanying with thermally responsive materials, displays well controlled drug release property, which is well-received as an outstanding design strategy for simultaneous photothermal/chemotherapy in cancer. Cyanine dye, as the prestigious photothermal agent has shown great potential due to its preeminent near-infrared absorbance and excellent thermal conversion efficiency. However, their inherent defect such as inferior photothermal stability, high leakage risk and poor therapy efficacy limit their further application in cancer therapy. Hence, a facile and universal strategy to make up these deficiencies is developed. Chemotherapeutic drug DOX and cyanine dye were loaded into polydopamine (PDA) nanoparticles. The PDA encapsulation dramatically improved the photothermal stability of cyanine dye. Attributed by the PDA structure feature, the thermo-sensitive small molecule glyamine (Gla) is introduced into the PDA surface to lessen leakage. The Gla can form a dense encapsulation layer on the dopamine surface through hydrogen bond. This newly fabricated Cyanine/DOX@PDA-Gla nanopaltform is characterized with NIR light/pH dual-responsive property, high NIR photothermal conversion performance and fluorescence guided chemo-photothermal therapy.

Harnessing astaxanthin-loaded diselenium cross-linked apotransferrin nanoparticles for the treatment of secretory otitis media

Secretory otitis media (SOM) is a clinical condition characterized by the accumulation of fluids and oxidative stress in the middle ear, leading to hearing impairment and infection complications. One potential solution for mitigating oxidative stress associated with SOM is the use of antioxidants such as astaxanthin. However, its effectiveness is limited due to its poor bioavailability and rapid oxidation. Herein, we developed a novel diselenium-crosslinked apotransferrin enriched with astaxanthin (AST@dSe-AFT) nanoparticles to augment the transport of astaxanthin across biological membranes, resulting in increased bioavailability and reduced oxidative stress in SOM. Our research demonstrated that AST@dSe-AFT efficiently accumulated in the middle ear, allowing for controlled delivery of astaxanthin in response to reactive oxygen species and reducing oxidative stress. Additionally, AST@dSe-AFT stimulated macrophages to polarize towards M2 phenotype and neutrophils to polarize towards N2 phenotype, thereby facilitating an anti-inflammatory response and tissue restoration. Importantly, AST@dSe-AFT exhibited no toxicity or adverse effects, suggesting its potential for safety and future clinical translation. Our findings suggested that AST@dSe-AFT represents a promising approach for the treatment of secretory otitis media and other oxidative stress-related disorders.

Knowledge-Based Design of Multifunctional Polymeric Nanoparticles

Conventional drug delivery systems (DDS) today still face several drawbacks and obstacles. High total doses of active pharmaceutical ingredients (API) are often difficult or impossible to deliver due to poor solubility of the API or undesired clearance from the body caused by strong interactions with plasma proteins. In addition, high doses lead to a high overall body burden, in particular if they cannot be delivered specifically to the target site. Therefore, modern DDS must not only be able to deliver a dose into the body, but should also overcome the hurdles mentioned above as examples. One of these promising devices are polymeric nanoparticles, which can encapsulate a wide range of APIs despite having different physicochemical properties. Most importantly, polymeric nanoparticles are tunable to obtain tailored systems for each application. This can already be achieved via the starting material, the polymer, by incorporating, e.g., functional groups. This enables the particle properties to be influenced not only specifically in terms of their interactions with APIs, but also in terms of their general properties such as size, degradability, and surface properties. In particular, the combination of size, shape, and surface modification allows polymeric nanoparticles to be used not only as a simple drug delivery device, but also to achieve targeting. This chapter discusses to what extent polymers can be designed to form defined nanoparticles and how their properties affect their performance.

Synergistic Phototherapy-Molecular Targeted Therapy Combined with Tumor Exosome Nanoparticles for Oral Squamous Cell Carcinoma Treatment

Oral squamous cell carcinoma (OSCC) contributes to more than 90% of all oral malignancies, yet the performance of traditional treatments is impeded by limited therapeutic effects and substantial side effects. In this work, we report a combinational treatment strategy based on tumor exosome-based nanoparticles co-formulating a photosensitizer (Indocyanine green) and a tyrosine kinase inhibitor (Gefitinib) (IG@EXOs) for boosting antitumor efficiency against OSCC through synergistic phototherapy-molecular targeted therapy. The IG@EXOs generate distinct photothermal/photodynamic effects through enhanced photothermal conversion efficiency and ROS generation, respectively. In vivo, the IG@EXOs efficiently accumulate in the tumor and penetrate deeply to the center of the tumor due to passive and homologous targeting. The phototherapy effects of IG@EXOs not only directly induce potent cancer cell damage but also promote the release and cytoplasmic translocation of Gefitinib for achieving significant inhibition of cell proliferation and tumor angiogenesis, eventually resulting in efficient tumor ablation and lymphatic metastasis inhibition through the synergistic phototherapy-molecular targeted therapy. We envision that the encouraging performances of IG@EXOs against cancer pave a new avenue for their future application in clinical OSCC treatment.

Double-Wavelength-Switchable Molecular Self-Assembly of a Photoacid and Spirooxazine in an Aqueous Solution

Quadruple-switchable nanoscale assemblies are built by combining two types of water-soluble molecular photoswitches through dipole-dipole interaction. Uniting the wavelength-specific proton dissociation of a photoacid and ring-opening of an anionic spirooxazine results in an assembly that can be addressed by irradiation with two different wavelengths: pH and darkness.

Folate-receptor-targeted co-self-assembly carrier-free gemcitabine nanoparticles loading indocyanine green for chemo-photothermal therapy

The carrier-free chemo-photothermal therapy has become a promising strategy to improve anti-cancer therapeutic efficacy owing to the combination of chemotherapy and photothermal therapy, with improved chemotherapy drug pharmacodynamics and pharmacokinetics, high drug loading, and reduced toxicity. We designed a novel carrier-free targeting nanoparticles, co-self-assembled amphiphilic prodrugs 3',5'-dioleoyl gemcitabine (DOG), and tumor-targeted γ-octadecyl folate (MOFA), with encapsulated US Food and Drug Administration (FDA)-approved photosensitizer indocyanine green (ICG) for synergistic chemo-photothermal therapy. The DOG linking oleic acid to the sugar moiety of gemcitabine (GEM) showed better self-assembly ability among GEM amphiphilic prodrugs linking different fatty acids. The readily available and highly reproducible 3',5'-dioleoyl gemcitabine/γ-octadecyl folate/indocyanine green (DOG/MOFA/ICG) nanoparticles were prepared by reprecipitation and showed nano-scale structure with mono-dispersity, great encapsulation efficiency of ICG (approximately 74%), acid- and laser irradiation-triggered GEM release in vitro and sustained GEM release in vivo after intravenous administration as well as excellent temperature conversion (57.0°C) with near-infrared laser irradiation. The combinational DOG/MOFA/ICG nanoparticles with near-infrared laser irradiation showed better anti-tumor efficacy than individual chemotherapy or photothermal therapy, with very low hemolysis and inappreciable toxicity for L929 cells. This co-self-assembly of the ICG and the chemotherapy drug (GEM) provides a novel tactic for the rational design of multifunctional nanosystems for targeting drug delivery and theranostics.

Design and fabrication of intracellular therapeutic cargo delivery systems based on nanomaterials: current status and future perspectives

Intracellular cargo delivery, the introduction of small molecules, proteins, and nucleic acids into a specific targeted site in a biological system, is an important strategy for deciphering cell function, directing cell fate, and reprogramming cell behavior. With the advancement of nanotechnology, many researchers use nanoparticles (NPs) to break through biological barriers to achieving efficient targeted delivery in biological systems, bringing a new way to realize efficient targeted drug delivery in biological systems. With a similar size to many biomolecules, NPs possess excellent physical and chemical properties and a certain targeting ability after functional modification on the surface of NPs. Currently, intracellular cargo delivery based on NPs has emerged as an important strategy for genome editing regimens and cell therapy. Although researchers can successfully deliver NPs into biological systems, many of them are delivered very inefficiently and are not specifically targeted. Hence, the development of efficient, target-capable, and safe nanoscale drug delivery systems to deliver therapeutic substances to cells or organs is a major challenge today. In this review, on the basis of describing the research overview and classification of NPs, we focused on the current research status of intracellular cargo delivery based on NPs in biological systems, and discuss the current problems and challenges in the delivery process of NPs in biological systems.

Multifunctional Covalent Organic Framework-Based Microneedle Patch for Melanoma Treatment

Melanoma is resistant to conventional chemotherapy and radiotherapy. Therefore, it is essential to develop a targeted, low-toxic, and minimally invasive treatment. Here, DTIC/ICG-Fe3O4@TpBD BSP/HA microneedles (MNs) were designed and fabricated, which can enhance targeting to melanoma and perform photothermal therapy (PTT) and chemotherapy simultaneously to synergistically exert anticancer effects. The system consisted of magnetic nanoparticles (DTIC/ICG-Fe3O4@TpBD), dissoluble matrix (Bletilla polysaccharide (BSP)/hyaluronic acid (HA)), and a polyvinyl alcohol backing layer. Due to the good magnetic responsiveness of Fe3O4@TpBD, dacarbazine (DTIC) and indocyanine green (ICG) can be better targeted to the tumor tissue and improve the therapeutic effect. BSP and HA have good biocompatibility and transdermal ability, so that the MNs can completely penetrate the tumor tissue, be dissolved by the interstitial fluid, and release DTIC and ICG. Under near-infrared (NIR) light irradiation, ICG converts light energy into thermal energy and induces ablation of B16-OVA melanoma cells. In vivo results showed that DTIC/ICG-Fe3O4@TpBD BSP/HA MNs combined with chemotherapy and PTT could effectively inhibit the growth of melanoma without tumor recurrence or significant weight loss in mice. Therefore, DTIC/ICG-Fe3O4@TpBD BSP/HA MNs are expected to provide new ideas and therapeutic approaches for the clinical treatment of melanoma.

LUMO-Mediated Se and HOMO-Mediated Te Nanozymes for Selective Redox Biocatalysis

Selenium (Se) and tellurium (Te) nanomaterials with novel chain-like structures have attracted widespread interest owing to their intriguing properties. Unfortunately, the still-unclear catalytic mechanisms have severely limited the development of biocatalytic performance. In this work, we developed chitosan-coated Se nanozymes with a 23-fold higher antioxidative activity than Trolox and bovine serum albumin coated Te nanozymes with stronger prooxidative biocatalytic effects. Based on density functional theory calculations, we first propose that the Se nanozyme with Se/Se2- active centers favored reactive oxygen species (ROS) clearance via a LUMO-mediated mechanism, while the Te nanozyme with Te/Te4+ active centers promoted ROS production through a HOMO-mediated mechanism. Furthermore, biological experiments confirmed that the survival rate of γ-irritated mice treated with the Se nanozyme was maintained at 100% for 30 days by inhibiting oxidation. However, the Te nanozyme had the opposite biological effect via promoting radiation oxidation. The present work provides a new strategy for improving the catalytic activities of Se and Te nanozymes.

Activatable Graphene Quantum-Dot-Based Nanotransformers for Long-Period Tumor Imaging and Repeated Photodynamic Therapy

Photodynamic therapy (PDT) is considered as an emerging therapeutic modality against cancer with high spatiotemporal selectivity because the utilized photosensitizers (PSs) are only active and toxic upon light irradiation. To maximize its effectiveness, PDT is usually applied repetitively for ablating various tumors. However, the total overdose of PSs from repeated administrations causes severe side effects. Herein, acidity-activated graphene quantum dots-based nanotransformers (GQD NT) are developed as PS vehicles for long-period tumor imaging and repeated PDT. Under the guidance of Arg-Gly-Asp peptide, GQD NT targets to tumor tissues actively, and then loosens and enlarges in tumor acidity, thus promising long tumor retention. Afterwards, GQD NT transforms into small pieces for better penetration in tumor. Upon laser irradiation, GQD NT generates mild hyperthermia that enhances cell membrane permeability and further promotes the PSs uptake. Most intriguingly, the as-prepared GQD NT not only "turns-on" fluorescence/magnetic resonance signals, but also achieves efficient repeated PDT. Notably, the total PSs dose is reduced to 3.5 µmol kg^-1 , which is 10-30 times lower than that of other reported works. Overall, this study exploits a smart vehicle to enhance accumulation, retention, and release of PSs in tumors through programmed deformation, thus overcoming the overdose obstacle in repeated PDT.

Theranostic applications of selenium nanomedicines against lung cancer

The incidence and mortality rates of lung cancer are among the highest in the world. Traditional treatment methods include surgery, chemotherapy, and radiotherapy. Although rapid progress has been achieved in the past decade, treatment limitations remain. It is therefore imperative to identify safer and more effective therapeutic methods, and research is currently being conducted to identify more efficient and less harmful drugs. In recent years, the discovery of antitumor drugs based on the essential trace element selenium (Se) has provided good prospects for lung cancer treatments. In particular, compared to inorganic Se (Inorg-Se) and organic Se (Org-Se), Se nanomedicine (Se nanoparticles; SeNPs) shows much higher bioavailability and antioxidant activity and lower toxicity. SeNPs can also be used as a drug delivery carrier to better regulate protein and DNA biosynthesis and protein kinase C activity, thus playing a role in inhibiting cancer cell proliferation. SeNPs can also effectively activate antigen-presenting cells to stimulate cell immunity, exert regulatory effects on innate and regulatory immunity, and enhance lung cancer immunotherapy. This review summarizes the application of Se-based species and materials in lung cancer diagnosis, including fluorescence, MR, CT, photoacoustic imaging and other diagnostic methods, as well as treatments, including direct killing, radiosensitization, chemotherapeutic sensitization, photothermodynamics, and enhanced immunotherapy. In addition, the application prospects and challenges of Se-based drugs in lung cancer are examined, as well as their forecasted future clinical applications and sustainable development.

Polyelectrolyte-multivalent molecule complexes: physicochemical properties and applications

The complexation of polyelectrolytes with other oppositely charged structures gives rise to a great variety of functional materials with potential applications in a wide spectrum of technological fields. Depending on the assembly conditions, polyelectrolyte complexes can acquire different macroscopic configurations such as dense precipitates, nanosized colloids and liquid coacervates. In the past 50 years, much progress has been achieved to understand the principles behind the phase separation induced by the interaction of two oppositely charged polyelectrolytes in aqueous solutions, especially for symmetric systems (systems in which both polyions have similar molecular weight and concentration). However, in recent years, the complexation of polyelectrolytes with alternative building blocks such as small charged molecules (multivalent inorganic species, oligopeptides, and oligoamines, among others) has gained attention in different areas. In this review, we discuss the physicochemical characteristics of the complexes formed by polyelectrolytes and multivalent small molecules, putting a special emphasis on their similarities with the well-known polycation-polyanion complexes. In addition, we analyze the potential of these complexes to act as versatile functional platforms in various technological fields, such as biomedicine and advanced materials engineering.

Nanotechnology-enabled immunogenic cell death for improved cancer immunotherapy

Tumor immunotherapy has revolutionized the field of oncology treatments in recent years. As one of the promising strategies of cancer immunotherapy, tumor immunogenic cell death (ICD) has shown significant potential for tumor therapy. Nanoparticles are widely used for drug delivery due to their versatile characteristics, such as stability, slow blood elimination, and tumor-targeting ability. To increase the specificity of ICD inducers and improve the efficiency of ICD induction, functionally specific nanoparticles, such as liposomes, nanostructured lipid carriers, micelles, nanodiscs, biomembrane-coated nanoparticles and inorganic nanoparticles have been widely reported as the vehicles to deliver ICD inducers in vivo. In this review, we summarized the strategies of different nanoparticles for ICD-induced cancer immunotherapy, and systematically discussed their advantages and disadvantages as well as provided feasible strategies for solving these problems. We believe that this review will offer some insights into the design of effective nanoparticulate systems for the therapeutic delivery of ICD inducers, thus, promoting the development of ICD-mediated cancer immunotherapy.

Responsive Nanostructure for Targeted Drug Delivery

Currently, intelligent, responsive biomaterials have been widely explored, considering the fact that responsive biomaterials provide controlled and predictable results in various biomedical systems. Responsive nanostructures undergo reversible or irreversible changes in the presence of a stimulus, and that stimuli can be temperature, a magnetic field, ultrasound, pH, humidity, pressure, light, electric field, etc. Different types of stimuli being used in drug delivery shall be explained here. Recent research progress in the design, development and applications of biomaterials comprising responsive nanostructures is also described here. More emphasis will be given on the various nanostructures explored for the smart stimuli responsive drug delivery at the target site such as wound healing, cancer therapy, inflammation, and pain management in order to achieve the improved efficacy and sustainability with the lowest side effects. However, it is still a big challenge to develop well-defined responsive nanostructures with ordered output; thus, challenges faced during the design and development of these nanostructures shall also be included in this article. Clinical perspectives and applicability of the responsive nanostructures in the targeted drug delivery shall be discussed here.

Use of stimulatory responsive soft nanoparticles for intracellular drug delivery

Drug delivery has made tremendous advances in the last decade. Targeted therapies are increasingly common, with intracellular delivery highly impactful and sought after. Intracellular drug delivery systems have limitations due to imprecise and non-targeted release profiles. One way this can be addressed is through using stimuli-responsive soft nanoparticles, which contain materials with an organic backbone such as lipids and polymers. The choice of biomaterial is essential for soft nanoparticles to be responsive to internal or external stimuli. The nanoparticle must retain its integrity and payload in non-targeted physiological conditions while responding to particular intracellular environments where payload release is desired. Multiple internal and external factors could stimulate the intracellular release of drugs from nanoparticles. Internal stimuli include pH, oxidation, and enzymes, while external stimuli include ultrasound, light, electricity, and magnetic fields. Stimulatory responsive soft nanoparticulate systems specifically utilized to modulate intracellular delivery of drugs are explored in this review.

Selenium-Containing Agents Acting on Cancer-A New Hope?

Selenium-containing agents are more and more considered as an innovative potential treatment option for cancer. Light is shed not only on the considerable advancements made in understanding the complex biology and chemistry related to selenium-containing small molecules but also on Se-nanoparticles. Numerous Se-containing agents have been widely investigated in recent years in cancer therapy in relation to tumour development and dissemination, drug delivery, multidrug resistance (MDR) and immune system-related (anti)cancer effects. Despite numerous efforts, Se-agents apart from selenocysteine and selenomethionine have not yet reached clinical trials for cancer therapy. The purpose of this review is to provide a concise critical overview of the current state of the art in the development of highly potent target-specific Se-containing agents.

Recent Insights into NIR-Light-Responsive Materials for Photothermal Cell Treatments

Controlling cells using photo-responsive materials is highly indispensable in the current biomedical sector. Considering the potential side effects of nanoparticles, it has become a challenge to control cells with photo-responsive materials. Recent studies have described several methods for controlling cell behavior using nanoparticles subjected to the near-infrared (NIR) laser light operating at the wavelength of 808 nm to 980 nm and at the power densities of 0.33 to 0.72 W·cm^-2. The challenge here is the preparation of biocompatible nanoparticles for both in vivo and in vitro studies and understanding cell behavior with an external light source recommended for biological application. Earlier studies have well documented many approaches and associated mechanisms for controlling cell behavior and the interaction between nanoparticles, cells, and appropriate external light sources. In this review, various nanomaterials such as metal nanomaterials and carbon-based nanomaterials are compared systematically regarding the effects of controlling cell behavior and inflammation by studying their mechanisms, route of administration, dose, and adverse effects such as toxicity and the interaction of nanoparticles with a specific wavelength of the light. Future directions should focus on stable and efficient light-responsive materials with minimal cytotoxicity.

Integrated Platform of Oxygen Self-enriched Nanovesicles: SP94 Peptide-directed Chemo/sonodynamic Therapy for Liver Cancer

Hepatocellular carcinoma (HCC) is a most common primary liver cancer among the most deadly malignancies. Selectively killing the cancer cells within the liver urgently requires the novel treatment strategies. The combination of sonodynamic therapy (SDT) and chemotherapy based on the nanotechnology have achieved some achievements in the HCC treatments. However, off-targeting drug delivery to healthy cells and the hypoxic microenvironment in the solid tumors frustrate the efforts to the combined strategy. The hypoxic microenvironment restrains the generation of ROS, leading to the decreased effects of SDT. To improve the clinical outcomes of chemo/SDT strategy, we created a novel oxygen self-enriched active targeted nanovesicle (ICG-DOX NPs/PFH@SP94-Lip). SP94 peptide could enhance the selectivity of the nanovesicles to liver tumor cells rather than normal liver cells. Besides, an oxygen carrier, perfluorohexanes (PFH), was co-loaded into liposomes to increase the oxygen level in tumor tissue, thus improving the effects of SDT. The in vivo studies showed that the ICG-DOX NPs/PFH@SP94-Lip combined with the external US stimulation significantly inhibited effects on tumor growth. Therefore, this novel oxygen self-enriched chemo/SDT nanocomposites represents a proof-of-concept liver tumor treatment strategy.

Nanoarchitectonics of Cartilage-Targeting Hydrogel Microspheres with Reactive Oxygen Species Responsiveness for the Repair of Osteoarthritis

Clinically, intra-articular administration can hardly achieve the truly targeted therapy, and the drugs are usually insufficient to show local and long-term therapeutic effects because of their rapid clearance. Herein, inspired by the phenomenon that bees track the scent of flowers to collect nectar, we developed cartilage-targeting hydrogel microspheres with reactive oxygen species (ROS)-responsive ability via combining the microfluidic method and photopolymerization processes to integrate cartilage-targeting peptides and ROS-responsive nanoparticles in the hydrogel matrix. The hydrogel microspheres with cartilage-targeting properties promoted better retention in the joint cavity and enhanced cellular uptake of the nanoparticles. Moreover, the ROS-responsive nanoparticles could react with osteoarthritis (OA)-induced intracellular ROS, resulting in the depolymerization of nanoparticles, which could not only eliminate excess ROS and reduce inflammation but also promote the release of dexamethasone (Dex) and kartogenin (KGN) in situ, realizing effective OA therapy. It was demonstrated that this hydrogel microsphere showed favorable ROS-responsive ability and enhanced chondrogenic differentiation as well as the downregulation of pro-inflammatory factors in vitro. Additionally, the hydrogel microspheres, similar to bees, could target and effectively repair cartilage in the OA model. Thus, the injectable hydrogel microspheres exerted an excellent potential to repair OA and may also provide an effective avenue for inflammatory bowel disease therapy.

Enhancing the therapeutic efficacy of nanoparticles for cancer treatment using versatile targeted strategies

Poor targeting of therapeutics leading to severe adverse effects on normal tissues is considered one of the obstacles in cancer therapy. To help overcome this, nanoscale drug delivery systems have provided an alternative avenue for improving the therapeutic potential of various agents and bioactive molecules through the enhanced permeability and retention (EPR) effect. Nanosystems with cancer-targeted ligands can achieve effective delivery to the tumor cells utilizing cell surface-specific receptors, the tumor vasculature and antigens with high accuracy and affinity. Additionally, stimuli-responsive nanoplatforms have also been considered as a promising and effective targeting strategy against tumors, as these nanoplatforms maintain their stealth feature under normal conditions, but upon homing in on cancerous lesions or their microenvironment, are responsive and release their cargoes. In this review, we comprehensively summarize the field of active targeting drug delivery systems and a number of stimuli-responsive release studies in the context of emerging nanoplatform development, and also discuss how this knowledge can contribute to further improvements in clinical practice.

Stimuli-Induced Architectural Transition as a Tool for Controlling the Enzymatic Degradability of Polymeric Micelles

Enzyme-responsive polymeric micelles hold great potential as drug delivery systems due to the overexpression of disease-associated enzymes. To achieve selective and efficient delivery of their therapeutic cargo, micelles need to be highly stable and yet disassemble when encountering their activating enzyme at the target site. However, increased micellar stability is accompanied by a drastic decrease in enzymatic degradability. The need to balance between stability and enzymatic degradation has severely limited the therapeutic applicability of enzyme-responsive nanocarriers. Here, we report a general modular approach for designing stable enzyme-responsive micelles whose enzymatic degradation can be enhanced on demand. The control over their response to the activating enzyme is achieved by stimuli-induced splitting of triblock amphiphiles into two identical diblock amphiphiles, which have the same hydrophilic-lipophilic balance as the parent amphiphile. This architectural transition drastically affects the micelle-unimer equilibrium and therefore increases the sensitivity of the micelles toward enzymatic degradation. As a proof of concept, we designed UV- and reduction-activated splitting mechanisms, demonstrating the ability to use architectural transition as a tool for tuning amphiphile-protein interactions, providing a general solution toward overcoming the stability-degradability barrier for enzyme-responsive nanocarriers.

Cell membrane-based biomimetic nanosystems for advanced drug delivery in cancer therapy: A comprehensive review

Natural types of cells display distinct characteristics with homotypic targeting and extended circulation in the blood, which are worthy of being explored as promising drug delivery systems (DDSs) for cancer therapy. To enhance their delivery efficiency, these cells can be combined with therapeutic agents and artificial nanocarriers to construct the next generation of DDSs in the form of biomimetic nanomedicines. In this review, we present the recent advances in cell membrane-based DDSs (CDDSs) and their applications for efficient cancer therapy. Different sources of cell membranes are discussed, mainly including red blood cells (RBC), leukocytes, cancer cells, stem cells and hybrid cells. Moreover, the extraction methods used for obtaining such cells and the mechanism contributing to the functional action of these biomimetic CDDSs are explained. Finally, a future perspective is proposed to highlight the limitations of CDDSs and the possible resolutions toward clinical transformation of currently developed biomimetic chemotherapies.

Stimuli-Responsive Hybrid Metal Nanocomposite - A Promising Technology for Effective Anticancer Therapy

Cancer is one of the most challenging, life-threatening illnesses to cure, with over 10 million new cases diagnosed each year globally. Improved diagnostic cum treatment with common side-effects are warranting for successful therapy. Nanomaterials are recognized to improve early diagnosis, imaging, and treatment. Recently, multifunctional nanocomposites attracted considerable interest due to their low-cost production, and ideal thermal and chemical stability, and will be beneficial in future diagnostics and customized treatment capacity. Stimuli-Responsive Hybrid Metal Nanocomposites (SRHMNs) based nanocomposite materials pose the on/off delivery of bioactive compounds such as medications, genes, RNA, and DNA to specific tissue or organs and reduce toxicity. They simultaneously serve as sophisticated imaging and diagnostic tools when certain stimuli (e.g., temperature, pH, redox, ultrasound, or enzymes) activate the nanocomposite, resulting in the imaging-guided transport of the payload at defined sites. This review in detail addresses the recent advancements in the design and mechanism of internal breakdown processes of the functional moiety from stimuli-responsive systems in response to a range of stimuli coupled with metal nanoparticles. Also, it provides a thorough understanding of SRHMNs, enabling non-invasive interventional therapy by resolving several difficulties in cancer theranostics.

Contact-Free Remote Manipulation of Hydrogel Properties Using Light-Triggerable Nanoparticles: A Materials Science Perspective for Biomedical Applications

Considerable progress has been made in synthesizing "intelligent", biodegradable hydrogels that undergo rapid changes in physicochemical properties once exposed to external stimuli. These advantageous properties of stimulus-triggered materials make them highly appealing to diverse biomedical applications. Of late, research on the incorporation of light-triggered nanoparticles (NPs) into polymeric hydrogel networks has gained momentum due to their ability to remotely tune hydrogel properties using facile, contact-free approaches, such as adjustment of wavelength and intensity of light source. These multi-functional NPs, in combination with tissue-mimicking hydrogels, are increasingly being used for on-demand drug release, preparing diagnostic kits, and fabricating smart scaffolds. Here, the authors discuss the atomic behavior of different NPs in the presence of light, and critically review the mechanisms by which NPs convert light stimuli into heat energy. Then, they explain how these NPs impact the mechanical properties and rheological behavior of NPs-impregnated hydrogels. Understanding the rheological behavior of nanocomposite hydrogels using different sophisticated strategies, including computer-assisted machine learning, is critical for designing the next generation of drug delivery systems. Next, they highlight the salient strategies that have been used to apply light-induced nanocomposites for diverse biomedical applications and provide an outlook for the further improvement of these NPs-driven light-responsive hydrogels.

Selenopeptide Nanomedicine Activates Natural Killer Cells for Enhanced Tumor Chemoimmunotherapy

Chemoimmunotherapy using nanotechnology has shown great potential for cancer therapy in the clinic. However, uncontrolled transportation and synergistic responses remain challenges. Here, a self-assembled selenopeptide nanoparticle that strengthens tumor chemoimmunotherapy through the activation of natural killer (NK) cells by the oxidative metabolite of the selenopeptide is developed. With the advantages of the enzyme-induced size-reduction and the reactive-oxygen-species-driven deselenization, this selenopeptide is able to deliver therapeutics, e.g., doxorubicin (DOX), to solid tumors and further activate the NK cells in a programmed manner. Importantly, in vitro and in vivo results prove the mutual promotion between the DOX-induced chemotherapy and the selenopeptide-induced immunotherapy, which synergistically contribute to the improved antitumor efficacy. It is anticipated that the selenopeptide may provide a type of promising stimuli-responsive immune modulator for versatile biomedical applications.

Nanocarrier-Based Tumor-Targeting Drug Delivery Systems for Hepatocellular Carcinoma Treatments: Enhanced Therapeutic Efficacy and Reduced Drug Toxicity

Hepatocellular carcinoma (HCC), due to the lack of efficient diagnostic methods and short of available treatments, becomes the third main cause of cancer deaths. Novel treatments for HCCs are thus in great need. The fast-growing area of drug delivery provides intriguing possibility to design nanocarriers with unique properties. The nanocarriers performanced as drug deliver vehicles enable the design of diverse drug delivery systems, which could serve multiple purposes, including improved bioavailability, controlled or triggered release and targeted delivery, leading to enhanced drug efficacy and lowered drug toxicity. This paper provides an overview on the types of delivery vehicles, functions of drug nanocarriers and types of ligand-based targeting systems and highlights the advances made towards better HCC treatments.

Doxorubicin-loaded graphene oxide nanocomposites in cancer medicine: Stimuli-responsive carriers, co-delivery and suppressing resistance

INTRODUCTION

The application of doxorubicin (DOX) in cancer therapy has been limited due to its drug resistance and poor internalization. Graphene oxide (GO) nanostructures have the capacity for DOX delivery while promoting its cytotoxicity in cancer.

AREAS COVERED

The favorable characteristics of GO nanocomposites, preparation method, and application in cancer therapy are described. Then, DOX resistance in cancer is discussed. The GO-mediated photothermal therapy and DOX delivery for cancer suppression are described. Preparation of stimuli-responsive GO nanocomposites, surface functionalization, hybrid nanoparticles, and theranostic applications are emphasized in DOX chemotherapy.

EXPERT OPINION

Graphene oxide nanoparticle-based photothermal therapy maximizes the anti-cancer activity of DOX against cancer cells. Apart from DOX delivery, GO nanomaterials are capable of loading anti-cancer agents and genetic tools to minimize drug resistance and enhance the cytolytic impact of DOX in cancer eradication. To enhance DOX accumulation in cancer cells, stimuli-responsive (redox-, light-, enzyme- and pH-sensitive) GO nanoparticles have been developed for DOX delivery. Further development of targeted delivery of DOX-loaded GO nanomaterials against cancer cells may be achieved by surface modification of polymers such as polyethylene glycol, hyaluronic acid, and chitosan. Doxorubicin-loaded GO nanoparticles have demonstrated theranostic potential for simultaneous diagnosis and therapy. Hybridization of GO with other nanocarriers such as silica and gold nanoparticles further broadens their potential anti-cancer therapy applications.

Targeted Delivery Methods for Anticancer Drugs

Simple Summary

The current main technological strategies for the delivery of anticancer drugs are discussed herein. This comprehensive review may help researchers design suitable delivery systems.

Abstract

Several drug-delivery systems have been reported on and often successfully applied in cancer therapy. Cell-targeted delivery can reduce the overall toxicity of cytotoxic drugs and increase their effectiveness and selectivity. Besides traditional liposomal and micellar formulations, various nanocarrier systems have recently become the focus of developmental interest. This review discusses the preparation and targeting techniques as well as the properties of several liposome-, micelle-, solid-lipid nanoparticle-, dendrimer-, gold-, and magnetic-nanoparticle-based delivery systems. Approaches for targeted drug delivery and systems for drug release under a range of stimuli are also discussed.

Rigid Polymer Network-Based Autonomous Photoswitches Working in the Solid State Encoded by Room-Temperature Phosphorescence

Autonomous molecular switches with self-recoverability are of great theoretical and experimental interest since they can avoid additional chemical or energy imposition during the working process. Due to the high energy barrier, however, the solid state is generally unfavorable for materials to exhibit the autonomous switch behavior. To promote the practical usage of the autonomous molecular switch, herein, we propose a prototype of an autonomous photoswitch that can work in the solid state based on a rigid polymer network. A hexacarboxylic sodium-modified hexathiobenzene compound was employed as a photoexcitation-driven unit, which can undergo molecular aggregation upon irradiation because of the distinct conformational difference between the ground state and the photoexcited state. Then, we selected a relatively rigid polymer named poly(dimethyldiallylammonium)chloride (PDDA) to complex with the hexacarboxylic sodium-modified hexathiobenzene through electrostatic coupling. Through optimization, the photoexcitation-controlled molecular aggregation and its self-recovery can work well in the solid matrix of PDDA under rhythmical photoirradiation. This process can be easily encoded by a self-recoverable room-temperature phosphorescence, featuring an excellent performance of the autonomous switch.

ROS-mediated liposomal dexamethasone: a new FA-targeted nanoformulation to combat rheumatoid arthritis via inhibiting iRhom2/TNF-α/BAFF pathways

Rheumatoid arthritis (RA) is an autoimmune inflammatory disorder that has seriously affected human health worldwide and its current management requires more successful therapeutic approaches. The combination of nanomedicines and pathophysiology into one system may provide an alternative strategy for precise RA treatment. In this work, a practical ROS-mediated liposome, abbreviated as Dex@FA-ROS-Lips that comprised synthetic dimeric thioether lipids (di-S-PC) and a surface functionalized with folic acid (FA), was proposed for dexamethasone (Dex) delivery. Incorporation with thioether lipids and a FA segment significantly improved the triggered release and improved the triggered release of cytotoxic Dex as well as the active targeting of RA, altering its overall pharmacokinetics and safety profiles in vivo. As proof, the designed Dex@FA-ROS-Lips demonstrated effective internalization by LPS-activated Raw264.7 macrophages with FA receptor overexpression and released Dex at the inflammatory site due to the ROS-triggered disassembly. Intravenous injection of this Dex@FA-ROS-Lips into adjuvant-induced arthritis (AIA) mice led to its incremental accumulation in inflamed joint tissues and significantly alleviated the cartilage destruction and joint swelling via suppression of proinflammatory cytokines (iRhom2, TNF-α and BAFF), as compared to the effect of commercial free Dex. Importantly, the Dex@FA-ROS-Lips nanoformulation showed better hemocompatibility with less adverse effects on the body weight and immune organ index of AIA mice. The anti-inflammatory mechanism of Dex@FA-ROS-Lips was further studied and it was found that it is possibly associated with the down-regulation of iRhom2 and the activation of the TNF-α/BAFF signaling pathway. Therefore, the integration of nanomedicines and the RA microenvironment using multifunctional Dex@FA-ROS-Lips shall be a novel RA treatment modality with full clinical potential, and based on the enhanced therapeutic effect, the signaling pathway of iRhom2/TNF-α/BAFF reasonably explained the mechanism of Dex@FA-ROS-Lips in anti-RA, which suggested a molecular target for RA therapy and other inflammatory diseases.

Photoactivatable Biomedical Materials Based on Luminogens with Aggregation-Induced Emission (AIE) Characteristics

Fluorescence probes with aggregation-induced emission (AIE) property are fascinating and vital in biological fields due to their bright fluorescence in the solid state. In contrast, traditional AIE materials are obscured by the off-target effects and lack of spatial and temporal control. Photoactivatable materials with AIE characteristics, whose physicochemical behaviors can be remotely activated by light, provide great potential in biochemical information acquisition with high spatial and temporal resolution. By using AIE-featured photoactivatable fluorescence probes, accurate analysis of the targets of interest is possible. For example, where, when, and to what extent a process is started or stopped by manipulating the non-invasive light accurately. Thus, many researchers are enthusiastic about developing AIE-featured photoactivatable materials and mainly focus on developing novel molecules by rational molecular structure design, and exploring advanced applications by appropriate molecular functionalization. In this review, the recent achievements of photoactivatable materials with AIE characteristics from the aspects involving inherent mechanism of photoactivity, molecular design strategy, and the corresponding applications in biological fields, are summarized. The biological applications are highlighted and discussed, including photoactivatable bioimaging, diagnosis, and photo-controlled therapy. Finally, the challenges and prospects of the AIE-featured photoactivatable materials are also outlined and discussed.

Tumor microenvironment and nanotherapeutics: intruding the tumor fort

Over recent years, advancements in nanomedicine have allowed new approaches to diagnose and treat tumors. Nano drug delivery systems exploit the enhanced permeability and retention (EPR) effect and enter the tumor tissue's interstitial space. However, tumor barriers play a crucial role, and cause inefficient EPR or the homing effect. Mounting evidence supports the hypothesis that the components of the tumor microenvironment, such as the extracellular matrix, and cellular and physiological components collectively or cooperatively hinder entry and distribution of drugs, and therefore, limit the theragnostic applications of cancer nanomedicine. This abnormal tumor microenvironment plays a pivotal role in cancer nanomedicine and was recently recognized as a promising target for improving nano-drug delivery and their therapeutic outcomes. Strategies like passive or active targeting, stimuli-triggered nanocarriers, and the modulation of immune components have shown promising results in achieving anticancer efficacy. The present review focuses on the tumor microenvironment and nanoparticle-based strategies (polymeric, inorganic and organic nanoparticles) for intruding the tumor barrier and improving therapeutic effects.

Recent advances in functionalized upconversion nanoparticles for light-activated tumor therapy

Upconversion nanoparticles (UCNPs) are a class of optical nanocrystals doped with lanthanide ions that offer great promise for applications in controllable tumor therapy. In recent years, UCNPs have become an important tool for studying the treatment of various malignant and nonmalignant cutaneous diseases. UCNPs convert near-infrared (NIR) radiation into shorter-wavelength visible and ultraviolet (UV) radiation, which is much better than conventional UV activated tumor therapy as strong UV-light can be damaging to healthy surrounding tissue. Moreover, UV light generally does not penetrate deeply into the skin, an issue that UCNPs can now address. However, the current studies are still in the early stage of research, with a long way to go before clinical implementation. In this paper, we systematically analysed recent advances in light-activated tumor therapy using functionalized UCNPs. We summarized the purpose and mechanism of UCNP-based photodynamic therapy (PDT), gene therapy, immunotherapy, chemo-therapy and integrated therapy. We believe the creation of functional materials based on UCNPs will offer superior performance and enable innovative applications, increasing the scope and opportunities for cancer therapy in the future.

Biological homeostasis-inspired light-excited multistage nanocarriers induce dual apoptosis in tumors

In the microenvironment of an organism, each element always regulates and compensates for each other's defects, finally achieving biostable equilibrium. Herein, inspired by the balance of biological homeostasis and the interconstraint of elements, light-responsive nanoparticle with anti-vascularization and oxygen-supplying ability such like a homeostasis body is constructed by the electrostatic adsorption of reactive oxygen species (ROS)-responsive copolymers with photosensitizers and oxygen donors, which act as the elements of homeostasis body can interact through multistage reactions forming a balance that induces double apoptosis including those caused by the photosensitizer itself and those induced after oxygenation. In this homeostasis body, the element photosensitizer can simultaneously generate hyperthermia and ROS. The former can not only inhibit the growth of blood vessels and promote cell necrosis, but induce the thermally responsive release of oxygen to alleviate tumor hypoxia for enhanced PDT. And the latter will induce rapid depolymerization of nanoparticles, promote the penetration and finally induce double apoptosis through multistage reactions. Immunofluorescence data further demonstrate that the nanoparticles significantly alleviated tumor hypoxia upon photoexcitation. Thus, such nanoparticles with multistage synergistic effects have demonstrated excellent effects in achieving biostable equilibrium to induce dual apoptosis and may also be a good strategy in hypoxic tumors therapy.

Nano-Drug Design Based on the Physiological Properties of Glutathione

Glutathione (GSH) is involved in and regulates important physiological functions of the body as an essential antioxidant. GSH plays an important role in anti-oxidation, detoxification, anti-aging, enhancing immunity and anti-tumor activity. Herein, based on the physiological properties of GSH in different diseases, mainly including the strong reducibility of GSH, high GSH content in tumor cells, and the NADPH depletion when GSSH is reduced to GSH, we extensively report the design principles, effect, and potential problems of various nano-drugs in diabetes, cancer, nervous system diseases, fluorescent probes, imaging, and food. These studies make full use of the physiological and pathological value of GSH and develop excellent design methods of nano-drugs related to GSH, which shows important scientific significance and prominent application value for the related diseases research that GSH participates in or responds to.

Recent developments in selenium-containing polymeric micelles: prospective stimuli, drug-release behaviors, and intrinsic anticancer activity

Selenium is capable of forming a dynamic covalent bond with itself and other elements and can undergo metathesis and regeneration reactions under optimum conditions. Its dynamic nature endows selenium-containing polymers with striking sensitivity towards some environmental alterations. In the past decade, several selenium-containing polymers were synthesized and used for the preparation of oxidation-, reduction-, and radiation-responsive nanocarriers. Recently, thioredoxin reductase, sonication, and osmotic pressure triggered the cleavage of Se-Se bonds and swelling or disassembly of nanostructures. Moreover, some selenium-containing nanocarriers form oxidation products such as seleninic acids and acrylates with inherent anticancer activities. Thus, selenium-containing polymers hold promise for the fabrication of ultrasensitive and multifunctional nanocarriers of radiotherapeutic, chemotherapeutic, and immunotherapeutic significance. Herein, we discuss the most recent developments in selenium-containing polymeric micelles in light of their architecture, multiple stimuli-responsive properties, emerging immunomodulatory activities, and future perspectives in the delivery and controlled release of anticancer agents.

A general prodrug nanohydrogel platform for reduction-triggered drug activation and treatment of taxane-resistant malignancies

Chemotherapy has been widely used for treating the vast majority of cancer patients. Unfortunately, only a fraction of patients can respond to chemotherapies, but these patients still experience severe side effects. In this context, a wide range of nanotherapeutic platforms have been developed with the aim of improving treatment outcomes while reducing drug toxicities. Nanohydrogels are highly appealing "smart" biocompatible and biodegradable vehicles for either local or systemic delivery of bioactive compounds. Here, we developed prodrug hydrogelators that can undergo one-step distillation-precipitation polymerization to form systemically injectable nanohydrogels. The optimized nanohydrogels were capable of rapidly releasing active agents (e.g., the cytotoxic agent cabazitaxel or the PI3K molecular inhibitor PI103) in response to the reducing tumor microenvironment, while drug release was very slow in the absence of the reductive reagent glutathione. Cabazitaxel-loaded nanogels showed preferential tumor accumulation, and administration of nanogels produced durable tumor regression in a docetaxel-resistant cervical tumor xenograft-bearing mouse model. More significantly, nanogel-based therapy was proven to demonstrate a higher safety profile than solution-based free cabazitaxel. Collectively, this study provides an alternative formulation that meets the essential requirements of high stability in the blood, spontaneous drug release at diseased sites, favorable safety in vivo, and translational capacity for further investigations. STATEMENT OF SIGNIFICANCE: Chemotherapy remains a considerable challenge and only a fraction of patients can respond to chemotherapies. Here we report an intratumoral reducing agent-activatable, tumor-targeting prodrug nanogel platform for therapeutic delivery. To this end, two anticancer agents (e.g., cytotoxic cabazitaxel or PI3K molecular inhibitor PI103) are tested. Prodrug nanogels are stable in the blood but performed reduction-triggered release of chemically unmodified drug molecules in cancerous tissues. Cabazitaxel-loaded nanogels exhibit satisfactory anticancer performance in a preclinical docetaxel-resistant tumor model. This is a practical and expedient approach that combines the prodrug strategy and nanogel scaffold to re-engineer a hydrophobic and toxic anticancer drug. The approach also is broadly applicable for the formulation of other agents to improve the therapeutic index.

Reactive oxygen species-sensitive polymeric nanocarriers for synergistic cancer therapy

Reactive oxygen species (ROS)-responsive nanocarriers have aroused widespread interest in recent years. On the one hand, a high ROS level has been detected in many types of tumor cells. On the other hand, ROS generation is also induced during photodynamic, sonodynamic, or chemodynamic therapy. In addition, multiple types of polymers are sensitive to ROS. Therefore, numerous ROS-responsive polymeric nanocarriers with unique ROS-responsive characteristics have been developed. This review discusses ROS-sensitive polymeric nanocarriers to improve drug delivery efficacy. In particular, ROS-responsive nanocarriers for synergistic cancer therapy are highlighted. The development of novel ROS-sensitive nanocarriers holds great potential for combining ROS-mediated therapy, such as photodynamic therapy, and other therapies to achieve synergistic anticancer efficacy. STATEMENT OF SIGNIFICANCE: Reactive oxygen species (ROS)-responsive nanocarriers aroused widespread interest in recent years. On the one hand, a high level of ROS has been found in many types of tumor cells. On the other hand, the ROS generation can also be induced during the photodynamic, sonodynamic, or chemodynamic therapy. Besides, multiple types of polymers were sensitive to the ROS. Therefore, numerous ROS-responsive polymeric nanocarriers with unique ROS responsive characteristics have been developed. This review focuses on the ROS-sensitive polymeric nanocarriers to improve drug delivery efficacy for synergistic cancer therapy.

Utilizing Stimuli Responsive Linkages to Engineer and Enhance Polymer Nanoparticle-Based Drug Delivery Platforms

The devastating nature of cancer continues to be one of the leading causes of death in the world. Chemotherapy is among the most common forms of cancer treatment but comes with a host of adverse effects caused by the therapeutic agents damaging healthy tissue and organs. To limit these side effects, scientists have been designing stimuli responsive drug delivery vessels for targeted release. This Review focuses on the incorporation of stimuli responsive linkages in targeted drug delivery systems to enhance therapeutic efficiency. These platforms are primarily employed to control the distribution of anticancer agents in the body to reduce the adverse side effects caused by their toxicities. We will outline how drug delivery vessels are constructed so that exposure to select environmental and external stimuli releases the enclosed drug only at the target site. Stimuli responsive components are integrated within drug delivery vessels in the form of cross-linkers, polymers, and surface modifications. The changes, these moieties undergo upon stimuli exposure, cascade into larger scale alterations to the platforms, resulting in complete disassembly, reversible morphological variations, and enhanced cellular uptake. The ability for these modes of delivery to be initiated exclusively under stimuli exposure allows for release of toxic therapeutic agents to be confined only to the affected area.