A DFX-based iron nanochelator for cancer therapy

Iron as an essential element, is involved in various cellular functions and maintaining cell viability, cancer cell is more dependent on iron than normal cell due to its chief characteristic of hyper-proliferation. Despite that some of the iron chelators exhibited potent and broad antitumor activity, severe systemic toxicities have limited their clinical application. Polyaminoacids, as both drug-delivery platform and therapeutic agents, have attracted great interests owing to their different medical applications and biocompatibility. Herein, we have developed a novel iron nanochelator PL-DFX, which composed of deferasirox and hyperbranched polylysine. PL-DFX has higher cytotoxicity than DFX and this effect can be partially reversed by Fe2+ supplementation. PL-DFX also inhibited migration and invasion of cancer cells, interfere with iron metabolism, induce phase G1/S arrest and depolarize mitochondria membrane potential. Additionally, the anti-tumor potency of PL-DFX was also supported by organoids derived from clinical specimens. In this study, DFX-based iron nanochelator has provided a promising and prospective strategy for cancer therapy via iron metabolism disruption.

Modulation of Macrophages Using Nanoformulations with Curcumin to Treat Inflammatory Diseases: A Concise Review

Curcumin (Cur), a traditional Chinese medicine extracted from natural plant rhizomes, has become a candidate drug for the treatment of diseases due to its anti-inflammatory, anticancer, antioxidant, and antibacterial activities. However, the poor water solubility and low bioavailability of Cur limit its therapeutic effects for clinical applications. A variety of nanocarriers have been successfully developed to improve the water solubility, in vivo distribution, and pharmacokinetics of Cur, as well as to enhance the ability of Cur to polarize macrophages and relieve macrophage oxidative stress or anti-apoptosis, thus accelerating the therapeutic effects of Cur on inflammatory diseases. Herein, we review the design and development of diverse Cur nanoformulations in recent years and introduce the biomedical applications and potential therapeutic mechanisms of Cur nanoformulations in common inflammatory diseases, such as arthritis, neurodegenerative diseases, respiratory diseases, and ulcerative colitis, by regulating macrophage behaviors. Finally, the perspectives of the design and preparation of future nanocarriers aimed at efficiently exerting the biological activity of Cur are briefly discussed.

Insights into stimuli-responsive diselenide bonds utilized in drug delivery systems for cancer therapy

Due to the complexity and particularity of cancer cell microenvironments, redox responsive drug delivery systems (DDSs) for cancer therapy have been extensively explored. Compared with widely reported cancer treatment systems based on disulfide bonds, diselenide bonds have better redox properties and greater anticancer efficiency. In this review, the significance and application of diselenide bonds in DDSs are summarized, and the stimulation sensitivity of diselenide bonds is comprehensively reported. The potential and prospects for the application of diselenide bonds in next-generation anticancer drug treatment systems are extensively discussed.

Nanoscale Drug Delivery Systems in Glioblastoma

Glioblastoma is the most aggressive cerebral tumor in adults. However, the current pharmaceuticals in GBM treatment are mainly restricted to few chemotherapeutic drugs and have limited efficacy. Therefore, various nanoscale biomaterials that possess distinct structure and unique property were constructed as vehicles to precisely deliver molecules with potential therapeutic effect. In this review, nanoparticle drug delivery systems including CNTs, GBNs, C-dots, MOFs, Liposomes, MSNs, GNPs, PMs, Dendrimers and Nanogel were exemplified. The advantages and disadvantages of these nanoparticles in GBM treatment were illustrated.

Layer-by-Layer Cell Encapsulation for Drug Delivery: The History, Technique Basis, and Applications

The encapsulation of cells with various polyelectrolytes through layer-by-layer (LbL) has become a popular strategy in cellular function engineering. The technique sprang up in 1990s and obtained tremendous advances in multi-functionalized encapsulation of cells in recent years. This review comprehensively summarized the basis and applications in drug delivery by means of LbL cell encapsulation. To begin with, the concept and brief history of LbL and LbL cell encapsulation were introduced. Next, diverse types of materials, including naturally extracted and chemically synthesized, were exhibited, followed by a complicated basis of LbL assembly, such as interactions within multilayers, charge distribution, and films morphology. Furthermore, the review focused on the protective effects against adverse factors, and bioactive payloads incorporation could be realized via LbL cell encapsulation. Additionally, the payload delivery from cell encapsulation system could be adjusted by environment, redox, biological processes, and functional linkers to release payloads in controlled manners. In short, drug delivery via LbL cell encapsulation, which takes advantage of both cell grafts and drug activities, will be of great importance in basic research of cell science and biotherapy for various diseases.

Tunable AggregationInduced Emission Fluorophore with the Assistance of the SelfAssembly of Block Copolymers by Controlling the Morphology and Secondary Conformation for Bioimaging

Aggregation-induced emission (AIE) luminogens with highly tunable properties show great potential for many applications. In this study, we synthesized a new family of AIE-type poly(ethylene glycol)-block-poly(9-anthrylmethyl lysine) (PEG-b-PLys-An) diblock copolymers by taking advantage of amphiphilic self-assembly and rigid helical backbones. These copolymers can self-assemble into various assemblies through nanoprecipitation methods. The micelles using N,N-dimethylformamide (DMF) as a cosolvent present brighter fluorescence than the vesicles prepared from tetrahydrofuran (THF). We demonstrate that the decreased solubility of copolymers in DMF results in the formation of more compact micelles with more excimer formation during the self-assembly process, while better solvent THF favors the formation of vesicles with stretched core chains. In addition, the secondary conformation of the polypeptide block shows pronounced effects on the fluorescence property. We further show the internalization of the assemblies using two types of cells by cellular uptake experiments. By the delicate design of the block copolymer, we successfully prepare the morphology- and conformation-dependent AIE materials for potential biomedical applications.

Functional Nanomedicines for Targeted Therapy of Bladder Cancer

Bladder cancer is one of most common malignant urinary tract tumor types with high incidence worldwide. In general, transurethral resection of non-muscle-invasive bladder cancer followed by intravesical instillation of chemotherapy is the standard treatment approach to minimize recurrence and delay progression of bladder cancer. However, conventional intravesical chemotherapy lacks selectivity for tumor tissues and the concentration of drug is reduced with the excretion of urine, leading to frequent administration and heavy local irritation symptoms. While nanomedicines can overcome all the above shortcomings and adhere to the surface of bladder tumors for a long time, and continuously and efficiently release drugs to bladder cancers. The rapid advances in targeted therapy have led to significant improvements in drug efficacy and precision of targeted drug delivery to eradicate tumor cells, with reduced side-effects. This review summarizes the different available nano-systems of targeted drug delivery to bladder cancer tissues. The challenges and prospects of targeted therapy for bladder cancer are additionally discussed.

Poly(α-l-lysine)-based nanomaterials for versatile biomedical applications: Current advances and perspectives

Poly(α-l-lysine) (PLL) is a class of water-soluble, cationic biopolymer composed of α-l-lysine structural units. The previous decade witnessed tremendous progress in the synthesis and biomedical applications of PLL and its composites. PLL-based polymers and copolymers, till date, have been extensively explored in the contexts such as antibacterial agents, gene/drug/protein delivery systems, bio-sensing, bio-imaging, and tissue engineering. This review aims to summarize the recent advances in PLL-based nanomaterials in these biomedical fields over the last decade. The review first describes the synthesis of PLL and its derivatives, followed by the main text of their recent biomedical applications and translational studies. Finally, the challenges and perspectives of PLL-based nanomaterials in biomedical fields are addressed.

Self-Assembled Micelles of Amphiphilic PEGylated Drugs for Cancer Treatment

Generally, poor solubility and imprecise delivery of chemotherapeutic drugs can compromise their efficacies for clinical cancer treatment. In order to address such concerns, poor water-soluble drugs are conjugated with poly(ethylene glycol) (PEG) to obtain PEGylated drugs, which have improved water solubility and can also self-assemble in an aqueous solution to form micelles (PEGylated drug micelles). The surface PEG layer enhances the micelles' colloidal stability and reduces the interaction with physiological surroundings. Meanwhile, PEGylated drug micelles are tumor- targeting via the enhanced permeation and retention (EPR) effect to improve antitumor efficacy in comparison with free drugs. PEGylated drug micelles employ drugs as parts of the carrier medium, which increases the micelles' drug loading capacity relatively. The development of stimuli- responsive PEGylated drug micelles facilitates the drug release to be smart and controllable. Moreover, the PEGylated drug micelles show great potentials in overcoming the challenges of cancer therapy, such as multidrug resistance (MDR), angiogenesis, immunosuppression, and so on. In this review, we highlight the research progresses of PEGylated drug micelles, including the structures and properties, smart stimuli-responsive PEGylated drug micelles, and the challenges that have been overcome by PEGylated drug micelles.

Nanoplatforms for Targeted Stimuli-Responsive Drug Delivery: A Review of Platform Materials and Stimuli-Responsive Release and Targeting Mechanisms

To achieve the promise of stimuli-responsive drug delivery systems for the treatment of cancer, they should (1) avoid premature clearance; (2) accumulate in tumors and undergo endocytosis by cancer cells; and (3) exhibit appropriate stimuli-responsive release of the payload. It is challenging to address all of these requirements simultaneously. However, the numerous proof-of-concept studies addressing one or more of these requirements reported every year have dramatically expanded the toolbox available for the design of drug delivery systems. This review highlights recent advances in the targeting and stimuli-responsiveness of drug delivery systems. It begins with a discussion of nanocarrier types and an overview of the factors influencing nanocarrier biodistribution. On-demand release strategies and their application to each type of nanocarrier are reviewed, including both endogenous and exogenous stimuli. Recent developments in stimuli-responsive targeting strategies are also discussed. The remaining challenges and prospective solutions in the field are discussed throughout the review, which is intended to assist researchers in overcoming interdisciplinary knowledge barriers and increase the speed of development. This review presents a nanocarrier-based drug delivery systems toolbox that enables the application of techniques across platforms and inspires researchers with interdisciplinary information to boost the development of multifunctional therapeutic nanoplatforms for cancer therapy.

Biodegradable and biocompatible spherical dendrimer nanoparticles with a gallic acid shell and a double-acting strong antioxidant activity as potential device to fight diseases from "oxidative stress"

Gallic acid (GA) is a natural polyphenol with remarkable antioxidant power present in several vegetables and fruits. A normal feeding regime leads to a daily intake of GA which is reasonably regarded as "natural" and "safe" for humans. It owns strong potentials as alternative to traditional drugs to treat several diseases triggered by oxidative stress (OS), but poor gastrointestinal absorbability, pharmacokinetic drawbacks, and fast metabolism limit its clinical application. In this work, a fifth-generation polyester-based dendrimer was firstly prepared as a better absorbable carrier to protect and deliver GA. Then, by its peripheral esterification with GA units, a GA-enriched delivering system (GAD) with remarkable antioxidant power and high potential against diseases from OS was achieved. Scanning electron microscopy results and dynamic light scattering analysis revealed particles with an average size around 387 and 375 nm, respectively, and an extraordinarily spherical morphology. These properties, by determining a large particles surface area, typically favour higher systemic residence time and bio-efficiency. Z-potential of - 25 mV suggests satisfactory stability in solution with tendency to form megamers and low polydispersity index. GAD showed intrinsic antioxidant power, higher than GA by 4 times and like prodrugs, and it can carry contemporary several bioactive GA units versus cells. In physiological condition, the action of pig liver esterase (PLE), selected as a model of cells esterase, hydrolyses GAD to non-cytotoxic small molecules, thus setting free the bioactive GA units, for further antioxidant effects. Cytotoxicity studies performed on two cell lines demonstrated a high cell viability. Graphical Abstract Graphical Abstract.

Improved Antitumor Outcomes for Colon Cancer Using Nanomicelles Loaded with the Novel Antitumor Agent LA67

Background

LA67 is a derivative of triptolide that exhibits strong antitumor activity. This derivative has a better safety profile than triptolide, but is limited by poor aqueous solubility.

Aim and Methods

To improve solubility and further increase therapeutic efficacy, we prepared LA67-loaded polymeric micelles (LA67-PMs) using a film hydration method. The physicochemical properties of LA67-PMs were investigated, and the antitumor activity of this formulation against Colon26 (C26) cancer cell line was evaluated in vitro and in vivo with LA67 as a control.

Results

Polymeric micelles containing LA67 had a particle size of 17.88 nm and a drug entrapment efficiency of 94.84%. This formulation dispersed completely in aqueous solution and exhibited slow, sustained release of LA67. Cellular uptake assay showed that LA67-PMs delivered LA67 to cancer cells with greater efficiency than free LA67, which resulted in increased LA67 accumulation in cancer cells. Cell counting kit 8 (CCK-8) assay showed that blank polymeric micelles (PMs) exhibited low toxicity and LA67-PMs exerted pronounced anti-proliferation effects against C26 cells. Furthermore, LA67-PMs induced apoptosis and repressed migration more effectively than free LA67. In vivo evaluation of antitumor activity showed that LA67-PMs inhibited tumor growth and distant organ metastasis to a greater extent than LA67, which resulted in improved survival rate. The potential mechanisms of these effects may have been induction of apoptosis, inhibition of cell proliferation, and neovascularization.

Conclusion

Our study showed that LA67-PMs may be a promising formulation for treatment of colon cancer.

Nanotechnology as a Platform for the Development of Injectable Parenteral Formulations: A Comprehensive Review of the Know-Hows and State of the Art

Within recent decades, the development of nanotechnology has made a significant contribution to the progress of various fields of study, including the domains of medical and pharmaceutical sciences. A substantially transformed arena within the context of the latter is the development and production of various injectable parenteral formulations. Indeed, recent decades have witnessed a rapid growth of the marketed and pipeline nanotechnology-based injectable products, which is a testimony to the remarkability of the aforementioned contribution. Adjunct to the ability of nanomaterials to deliver the incorporated payloads to many different targets of interest, nanotechnology has substantially assisted to the development of many further facets of the art. Such contributions include the enhancement of the drug solubility, development of long-acting locally and systemically injectable formulations, tuning the onset of the drug’s release through the endowment of sensitivity to various internal or external stimuli, as well as adjuvancy and immune activation, which is a desirable component for injectable vaccines and immunotherapeutic formulations. The current work seeks to provide a comprehensive review of all the abovementioned contributions, along with the most recent advances made within each domain. Furthermore, recent developments within the domains of passive and active targeting will be briefly debated.

Therapeutic potential of polypeptide-based conjugates: Rational design and analytical tools that can boost clinical translation

The clinical success of polypeptides as polymeric drugs, covered by the umbrella term "polymer therapeutics," combined with related scientific and technological breakthroughs, explain their exponential growth in the development of polypeptide-drug conjugates as therapeutic agents. A deeper understanding of the biology at relevant pathological sites and the critical biological barriers faced, combined with advances regarding controlled polymerization techniques, material bioresponsiveness, analytical methods, and scale up-manufacture processes, have fostered the development of these nature-mimicking entities. Now, engineered polypeptides have the potential to combat current challenges in the advanced drug delivery field. In this review, we will discuss examples of polypeptide-drug conjugates as single or combination therapies in both preclinical and clinical studies as therapeutics and molecular imaging tools. Importantly, we will critically discuss relevant examples to highlight those parameters relevant to their rational design, such as linking chemistry, the analytical strategies employed, and their physicochemical and biological characterization, that will foster their rapid clinical translation.

Acidity-responsive shell-sheddable camptothecin-based nanofibers for carrier-free cancer drug delivery

Small molecular prodrugs that self-assemble into nanoparticles have many advantages over commonly studied nanomedicines based upon nanoscale carriers such as liposomes, micelles and polymeric nanoparticles. These carrier-free nanodrugs exhibit favorable nanoproperties without the help of a nanocarrier, and they have many unique merits, such as a simple synthetic procedure, well-defined structure and high drug loading capacity. To date, most of these carrier-free nanodrugs have been spherical and very few nonspherical nanodrugs have been synthesized and studied. Herein, we report a camptothecin (CPT) prodrug that self-assembles into nanofibers. These carrier-free CPT nanofibers have a width of approximately one hundred nanometers and a length of several micrometers. The cellular uptake and tumor penetration behaviour of these nanofibers were observed by time-lapse video microscopy. These nanofibers can rapidly enter cancer cells by penetrating the cell membrane, gradually dissolve intracellularly and efficiently release the active drug. Coating the surface of these nanofibers with a pH-responsive PEG layer improves the stability of these nanofibers and shields their positive charge to minimize nonspecific interactions. These pH-responsive nanofibers are sheddable in the acidic tumor microenvironment and deliver carried cargoes deep into tumors. Our findings demonstrate that small molecular CPT prodrugs that form nanofibers are efficient for cancer drug delivery.

Dual-targeting nanoparticles with core-crosslinked and pH/redox-bioresponsive properties for enhanced intracellular drug delivery

Multifunctional nanoparticles (NPs) with high blood-stability, tumor-targeting ability, and stimuli-bioresponsive drug release behaviors are urgently demanded. Herein, folic acid (FA) and galactose (GAL) functionalized, core-crosslinked NPs (CC NPs) with dual-targeting and pH/redox-bioresponsive properties were developed based on amphiphilic FA-poly(6-O-methacryloyl-d-galactopyranose)-b-poly[2-(diisopropylamino) ethyl methacrylate-co-pyridyl disulfide methylacrylate] [FA-PMAgGP-b-P(DPA-co-PDEMA), termed as FA-PMgDP] block copolymers, and then investigated for facilitated hepatoma-targeting delivery of doxorubicin (DOX). A series of PMgDP copolymers were synthesized though two-step RAFT copolymerization followed by acid-induced acetal deprotection reaction. Their well-defined chemical structures and compositions were characterized by ¹H NMR and gel permeation chromatography. Nano-sized, non-crosslinked PMgDP NPs (PMgDP NC NPs) with sizes of less than 25 nm in aqueous solution were self-assembled via the solvent exchange method, and PMgDP CC NPs were readily prepared in the presence of dithiothreitol. The drug-loading content of PMgDP CC NPs was up to 15.8% and its entrapment efficiency was 89.0%. In normal physiological conditions, 11.6% of DOX was released from DOX-loaded PMgDP CC NPs at 25 h, whereas in analogous intracellular microenvironment, 95.5% was released at 11 h owing to the acid-induced protonation of tertiary amine and reductive cleavage of disulfide bond in the hydrophobic core. In a cellular uptake study, FA and GAL-mediated, active, dual-targeted DOX-loaded FA-PMgDP CC NPs showed a 3.54-fold increase in cellular uptake efficiency to HepG2 cells compared to that of shown by single GAL-targeted, DOX-loaded PMgDP NC NPs. Results of in vitro cytotoxicity study showed that blank FA-PMgDP CC NPs exhibited good biocompatibility, whereas dual-targeting DOX-loaded FA-PMgDP CC NPs increased cell apoptosis. Therefore, the above results indicated that the well-constructed FA-PMgDP CC NPs with multi-synergistic effect may serve as new nanocarriers in the field of precise hepatoma-targeting drug delivery.

Intracellular GSH-responsive camptothecin delivery systems

Smart GSH-responsive camptothecin delivery systems for treatment of tumors and real-time monitoring in vivo and in vitro were described.

Preparation of poly-l-lysine-based nanoparticles with pH-sensitive release of curcumin for targeted imaging and therapy of liver cancer in vitro and in vivo

Poly-l-lysine (PLL) nanoparticle (NP) system was prepared for the controlled release of curcumin (CUR) by pH stimuli, and its theranostic efficacy on cancer was compared to that of CUR solution in vitro and in vivo. Deoxycholic acid (DOCA), methoxy polyethylene glycol (MPEG) and cyanine 5.5 (cy5.5) were conjugated to the amine group of PLL through condensation reaction (PLL-DOCA-MPEG-cy5.5), followed by encapsulation of CUR by dialysis method (PLL-DOCA-MPEG-cy5.5/CUR NPs). The composition, morphology and size distribution of PLL-DOCA-MPEG-cy5.5 NPs were characterized by proton nuclear magnetic resonance (1H NMR), transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively. In vitro tests exhibited that changes in the charge and size of the NPs at low pH led to the improved cellular uptake of CUR into human hepatoma Hep3B cell line by electrostatically absorptive endocytosis. PEGylation with MPEG was turn out to be very effective to have a prolonged blood circulation time, in turn increased the EPR effect. In addition, the incorporation of Cy5.5 into NPs provided successful biodistribution images in vivo and ex vivo. Our findings suggest that PLL-DOCA-MPEG-cy5.5/CUR NPs may have promising applications in cancer theranosis.

Microfluidics for Cancer Nanomedicine: From Fabrication to Evaluation

Self-assembled drug delivery systems (sDDSs), made from nanocarriers and drugs, are one of the major types of nanomedicines, many of which are in clinical use, under preclinical investigation, or in clinical trials. One of the hurdles of this type of nanomedicine in real applications is the inherent complexity of their fabrication processes, which generally lack precise control over the sDDS structures and the batch-to-batch reproducibility. Furthermore, the classic 2D in vitro cell model, monolayer cell culture, has been used to evaluate sDDSs. However, 2D cell culture cannot adequately replicate in vivo tissue-level structures and their highly complex dynamic 3D environments, nor can it simulate their functions. Thus, evaluations using 2D cell culture often cannot correctly correlate with sDDS behaviors and effects in humans. Microfluidic technology offers novel solutions to overcome these problems and facilitates studying the structure-performance relationships for sDDS developments. In this Review, recent advances in microfluidics for 1) fabrication of sDDSs with well-defined physicochemical properties, such as size, shape, rigidity, and drug-loading efficiency, and 2) fabrication of 3D-cell cultures as "tissue/organ-on-a-chip" platforms for evaluations of sDDS biological performance are in focus.

Recent advances of dicyano-based materials in biology and medicine

We highlight the development of dicyano-based fluorescent materials in biology and medicine.

Precise ratiometric loading of PTX and DOX based on redox-sensitive mixed micelles for cancer therapy

PTX and DOX have different anticancer mechanisms. The combination of the two anticancer drugs could synergically enhance their anticancer effect, but simultaneously accompanied by severe side effects. In the present study, we constructed a mixed micelle system based on redox-sensitive mPEG-SS-PTX and mPEG-SS-DOX conjugate. The drug delivery system has a fixed and high drug loading content of 24.2% (PTX∼14.8% and DOX∼9.4%) with a precise ratio of PTX and DOX to realize the synchronized and controlled release. The mixed micelle has an average size of 93.3nm with a narrow distribution, suitable for passive targeting to tumor tissues by the EPR effect. In vitro release profile and in vitro anticancer results show the mixed micelles have obvious redox-sensitive release properties in reducing environment and have a significant cytotoxicity to A549 and B16 cells. Importantly, in vivo study shows the mixed micelles have no obvious side effect on mice compared to free PTX/DOX samples during the treatment. Therefore, the constructed redox-sensitive mixed micelle is a promising drug delivery system for cancer therapy.

Rational Design of Cancer Nanomedicine: Nanoproperty Integration and Synchronization

Current cancer nanomedicines can only mitigate adverse effects but fail to enhance therapeutic efficacies of anticancer drugs. Rational design of next-generation cancer nanomedicines should aim to enhance their therapeutic efficacies. Taking this into account, this review first analyzes the typical cancer-drug-delivery process of an intravenously administered nanomedicine and concludes that the delivery involves a five-step CAPIR cascade and that high efficiency at every step is critical to guarantee high overall therapeutic efficiency. Further analysis shows that the nanoproperties needed in each step for a nanomedicine to maximize its efficiency are different and even opposing in different steps, particularly what the authors call the PEG, surface-charge, size and stability dilemmas. To resolve those dilemmas in order to integrate all needed nanoproperties into one nanomedicine, stability, surface and size nanoproperty transitions (3S transitions for short) are proposed and the reported strategies to realize these transitions are comprehensively summarized. Examples of nanomedicines capable of the 3S transitions are discussed, as are future research directions to design high-performance cancer nanomedicines and their clinical translations.

A self-immolative and DT-diaphorase-activatable prodrug for drug-release tracking and therapy

A DT-diaphorase-activatable theranostic prodrug has been developed for visualizing the release of active drug and enhancing the therapeutic effect.

A two-photon-activated prodrug for therapy and drug release monitoring

A two-photon-activated prodrug has been developed for drug release monitoring and photo-controllable therapy.

Dual cellular stimuli-responsive hydrogel nanocapsules for delivery of anticancer drugs

In this work, we report dual cellular environmental stimuli-responsive hydrogel nanocapsules (HA-NCs) for delivery of an anticancer drug (doxorubicin, DOX). This nanocapsule drug delivery system was specially designed to be triggered by stimuli in intra-cellular environments, specifically high glutathione (GSH) concentration and low pH. Biocompatible hyaluronan was used as the basic nanocapsule shell building material. Chemical modifications were conducted in order to functionalize it; specifically, GSH cleavable crosslinking sites and pH responsive expansion sites were introduced. After passive delivery to tumor sites via an enhanced permeation and retention (EPR) effect and cellular uptake, the nanocapsule shells underwent a swelling/disassembly process due to high GSH concentration (e.g., 10 mM), which induced cleavage of disulfide (S-S) bonds, and low pH (e.g., pH 5), which caused water influx associated with deprotection of the acetal groups. This process enabled rupture of the hydrogel nanocapsules and therefore resulted in release of the encapsulated payloads. This hydrogel nanocapsule system exhibited a great ability to release the vast majority of the encapsulated DOX in tumor cells, as proven by the remarkably (4.7-fold) accelerated drug release rate within tumor cells (pH 5.0, GSH 10 mM), in sharp contrast to the drug release rate under physiological conditions (pH 7.4, GSH 0). In vitro bio-evaluation showed the good biocompatibility of the nanocapsule carriers and their efficient cancer cell growth inhibition activity after drug encapsulation. In vivo studies confirmed that the DOX containing nanocapsules (DOX/HA-NCs) had comparable antitumor efficiency and greatly reduced side effects as compared with free DOX (DOX·HCl).

A stimuli-responsive Janus peptide dendron–drug conjugate as a safe and nanoscale drug delivery vehicle for breast cancer therapy

A Janus mPEGylated dendron–PVGLIG–DOX conjugate self-assembled into nanoparticles was employed as a matrix metalloproteinase-2/9 enzyme-sensitive and safe nanoscale drug delivery system for breast cancer therapy.

Dendrimers with the protocatechuic acid building block for anticancer drug delivery

Protocatechuic acid (3,4-dihydroxybenzoic acid; PCA) is a well-known antioxidant compound and a potential antitumor drug that is commonly found in fruits and vegetables.

Well-defined labile diselenide-centered poly(ε-caprolactone)-based micelles for activated intracellular drug release

Diselenide groups were introduced into aliphatic polyesters to develop a novel well-defined reduction-labile biodegradable diselenide-containing polymeric drug delivery system (mPEG–PCL–Se)₂.

Synthesis of the first POSS cage–anthracycline conjugates via amide bonds

Synthetic routes leading to nanoconjugates of polyhedral silsesquioxane T₈ with doxorubicin and daunorubicin have been developed.

Redox-mediated dissociation of PEG–polypeptide-based micelles for on-demand release of anticancer drugs

The biocompatible polypeptide-based micelles that can rapidly disassemble for on-demand release of DOX under a redox environment are reported.