Supramolecular nanodevices: from design validation to theranostic nanomedicine

Photoactivation of Ligands for Extrinsically and Intrinsically Triggered Disassembly of Amphiphilic Nanoassemblies

Specific response to the concurrent presence of two different inputs is one of the hallmarks of incorporating specificities in nature. Artificial nanoassemblies that concurrently respond to two very different inputs are of great interest in a variety of applications, especially in biomedicine. Here, we present a design strategy for amphiphilic nanoassemblies with such capabilities, enabled by photocaging a ligand moiety that is capable of binding to a specific protein. New molecular designs that offer nanoassemblies that respond to either of two inputs or only to the concurrent presence of two inputs are outlined. Such biomimetic nanoassemblies could find use in many applications, including drug delivery and diagnostics.

pH-Responsive diblock copolymers with two different fluorescent labels for simultaneous monitoring of micellar self-assembly and degree of protonation

Facile labelling of both blocks of a pH-responsive diblock copolymer with different fluorophores allows monitoring of polymer aggregation and deprotonation.

Dual-responsive recurrent self-assembly of a supramolecular polymer based on the host–guest complexation interaction between β-cyclodextrin and azobenzene

A novel supramolecular polymer PAE-g-Azo@β-CD-PEG was constructed, which significantly displayed pH- and photo-dual-responsive recurrent self-assembly behaviors.

In Vivo Tumor-Targeted Dual-Modality PET/Optical Imaging with a Yolk/Shell-Structured Silica Nanosystem

Silica nanoparticles have been one of the most promising nanosystems for biomedical applications due to their facile surface chemistry and non-toxic nature. However, it is still challenging to effectively deliver them into tumor sites and noninvasively visualize their in vivo biodistribution with excellent sensitivity and accuracy for effective cancer diagnosis. In this study, we design a yolk/shell-structured silica nanosystem ⁶⁴Cu-NOTA-QD@HMSN-PEG-TRC105, which can be employed for tumor vasculature targeting and dual-modality PET/optical imaging, leading to superior targeting specificity, excellent imaging capability and more reliable diagnostic outcomes. By combining vasculature targeting, pH-sensitive drug delivery, and dual-modality imaging into a single platform, as-designed yolk/shell-structured silica nanosystems may be employed for the future image-guided tumor-targeted drug delivery, to further enable cancer theranostics.

Effect of an external electric field on capillary filling of water in hydrophilic silica nanochannels

Development of functional nanofluidic devices requires understanding the fundamentals of capillary driven flow in nanochannels.

Metal–organic framework nanoparticles for magnetic resonance imaging

This review aims to integrate the state-of-the-art of MOF nanoparticles and their use in MRI. It gives an overview of the work done so far, focusing especially on the clinical applicability. Furthermore, it summarises the different factors for MR signal formation mechanisms important for the development of MR active nanoparticles and provides suggestions for a better comparison between different studies.

New Generation Nanomedicines Constructed from Self-Assembling Small-Molecule Prodrugs Alleviate Cancer Drug Toxicity

The therapeutic index for chemotherapeutic drugs is determined in part by systemic toxicity, so strategies for dose intensification to improve efficacy must also address tolerability. In addressing this issue, we have investigated a novel combinatorial strategy of reconstructing a drug molecule and using sequential drug-induced nanoassembly to fabricate supramolecular nanomedicines (SNM). Using cabazitaxel as a target agent, we established that individual synthetic prodrugs tethered with polyunsaturated fatty acids were capable of recapitulating self-assembly behavior independent of exogenous excipients. The resulting SNM could be further refined by PEGylation with amphiphilic copolymers suitable for preclinical studies. Among these cabazitaxel derivatives, docosahexaenoic acid-derived compound 1 retained high antiproliferative activity. SNM assembled with compound 1 displayed an unexpected enhancement of tolerability in animals along with effective therapeutic efficacy in a mouse xenograft model of human cancer, compared with free drug administered in its clinical formulation. Overall, our studies showed how attaching flexible lipid chains to a hydrophobic and highly toxic anticancer drug can convert it to a systemic self-deliverable nanotherapy, preserving its pharmacologic efficacy while improving its safety profile. Cancer Res; 77(24); 6963-74. ©2017 AACR.

Synthesis and Application of Aurophilic Poly(Cysteine) and Poly(Cysteine)-Containing Copolymers

The redox capacity, as well as the aurophilicity of the terminal thiol side groups, in poly(Cysteine) lend a unique characteristic to this poly(amino acid) or polypeptide. There are two major application fields for this polymer: (i) biomedical applications in drug delivery and surface modification of biomedical devices and (ii) as coating for electrodes to enhance their electrochemical sensitivity. The intended application determines the synthetic route for p(Cysteine). Polymers to be used in biomedical applications are typically polymerized from the cysteine N-carboxyanhydride by a ring-opening polymerization, where the thiol group needs to be protected during the polymerization. Advances in this methodology have led to conditions under which the polymerization progresses as living polymerization, which allows for a strict control of the molecular architecture, molecular weight and polydispersity and the formation of block copolymers, which eventually could display polyphilic properties. Poly(Cysteine) used as electrode coating is typically polymerized onto the electrode by cyclic voltammetry, which actually produces a continuous, pinhole-free film on the electrode via the formation of covalent bonds between the amino group of Cysteine and the carbon of the electrode. This resulting coating is chemically very different from the well-defined poly(Cysteine) obtained by ring-opening polymerizations. Based on the structure of cysteine a significant degree of cross-linking within the coating deposited by cyclic voltammetry can be assumed. This manuscript provides a detailed discussion of the ring-opening polymerization of cysteine, a brief consideration of the role of glutathione, a key cysteine-containing tripeptide, and examples for the utilization of poly(Cysteine) and poly(Cysteine)-containing copolymers, in both, the biomedical as well as electrochemical realm.

Transforming doxorubicin into a cancer stem cell killer via EpCAM aptamer-mediated delivery

Chemotherapy-resistant cancer stem cells (CSCs) are a major obstacle to the effective treatment of many forms of cancer. To overcome CSC chemo-resistance, we developed a novel system by conjugating a CSC-targeting EpCAM aptamer with doxorubicin (Apt-DOX) to eliminate CSCs. Incubation of Apt-DOX with colorectal cancer cells resulted in high concentration and prolonged retention of DOX in the nuclei. Treatment of tumour-bearing xenograft mice with Apt-DOX resulted in at least 3-fold more inhibition of tumour growth and longer survival as well as a 30-fold lower frequency of CSC and a prolonged longer tumourigenic latency compared with those receiving the same dose of free DOX. Our data demonstrate that a CSC-targeting aptamer is able to transform a conventional chemotherapeutic agent into a CSC-killer to overcome drug resistance in solid tumours.

Paclitaxel-loaded and A10-3.2 aptamer-targeted poly(lactide-co-glycolic acid) nanobubbles for ultrasound imaging and therapy of prostate cancer

In the current study, we synthesized prostate cancer-targeting poly(lactide-co-glycolic acid) (PLGA) nanobubbles (NBs) modified using A10-3.2 aptamers targeted to prostate-specific membrane antigen (PSMA) and encapsulated paclitaxel (PTX). We also investigated their impact on ultrasound (US) imaging and therapy of prostate cancer. PTX-A10-3.2-PLGA NBs were developed using water-in-oil-in-water (water/oil/water) double emulsion and carbodiimide chemistry approaches. Fluorescence imaging together with flow cytometry verified that the PTX-A10-3.2-PLGA NBs were successfully fabricated and could specifically bond to PSMA-positive LNCaP cells. We speculated that, in vivo, the PTX-A10-3.2-PLGA NBs would travel for a long time, efficiently aim at prostate cancer cells, and sustainably release the loaded PTX due to the improved permeability together with the retention impact and US-triggered drug delivery. The results demonstrated that the combination of PTX-A10-3.2-PLGA NBs with low-frequency US achieved high drug release, a low 50% inhibition concentration, and significant cell apoptosis in vitro. For mouse prostate tumor xenografts, the use of PTX-A10-3.2-PLGA NBs along with low-frequency US achieved the highest tumor inhibition rate, prolonging the survival of tumor-bearing nude mice without obvious systemic toxicity. Moreover, LNCaP xenografts in mice were utilized to observe modifications in the parameters of PTX-A10-3.2-PLGA and PTX-PLGA NBs in the contrast mode and the allocation of fluorescence-labeled PTX-A10-3.2-PLGA and PTX-PLGA NBs in live small animals and laser confocal scanning microscopy fluorescence imaging. These results demonstrated that PTX-A10-3.2-PLGA NBs showed high gray-scale intensity and aggregation ability and showed a notable signal intensity in contrast mode as well as aggregation ability in fluorescence imaging. In conclusion, we successfully developed an A10-3.2 aptamer and loaded PTX-PLGA multifunctional theranostic agent for the purpose of obtaining US images of prostate cancer and providing low-frequency US-triggered therapy of prostate cancer that was likely to constitute a strategy for both prostate cancer imaging and chemotherapy.

Functional Built-In Template Directed Siliceous Fluorescent Supramolecular Vesicles as Diagnostics

Functional template directed synthesis of hybrid siliceous fluorescent vesicle (HSFV) is fabricated by using fluorescent vesicle as a built-in template. The template vesicle is the ionic self-assembly of an aggregation-induced emission (AIE) fluorogen. Upon depositing folic acid modified silica shell on its surface, the obtained HSFVs display low cytotoxicity, significant fluorescence, and targeted drug delivery toward cancer cells. Furthermore, the wall-thickness of the HSFVs can be controlled via altered concentration of silica source. This is the first report of HSFV employing the template vesicle as a built-in fluorescent agent, which represents a good example of rational design for an effective diagnostics, and may open up a new avenue for precision medicine.

Antibody-powered nucleic acid release using a DNA-based nanomachine

A wide range of molecular devices with nanoscale dimensions have been recently designed to perform a variety of functions in response to specific molecular inputs. Only limited examples, however, utilize antibodies as regulatory inputs. In response to this, here we report the rational design of a modular DNA-based nanomachine that can reversibly load and release a molecular cargo on binding to a specific antibody. We show here that, by using three different antigens (including one relevant to HIV), it is possible to design different DNA nanomachines regulated by their targeting antibody in a rapid, versatile and highly specific manner. The antibody-powered DNA nanomachines we have developed here may thus be useful in applications like controlled drug-release, point-of-care diagnostics and in vivo imaging.

Responsive molecular machines can perform specific tasks triggered by environmental or chemical stimuli. Here, the authors show that antibodies can be used as inputs to modulate the binding of a molecular cargo to a designed DNA-based nanomachine, with potential applications in diagnostics and drug delivery.

Expanding the potential of MRI contrast agents through multifunctional polymeric nanocarriers

MRI is a sought-after, noninvasive tool in medical diagnostics, yet the direct application of contrast agents to tissue suffers from several drawbacks. Hosting the contrast agents in polymeric nanocarriers can solve many of these issues while creating additional benefit through exploitation of the intrinsic characteristics of the polymeric carriers. In this report, the versatility is highlighted with recent examples of dendritic and hyperbranched polymers, polymer nanoparticles and micelles, and polymersomes as multifunctional bioresponsive nanocarriers for MRI contrast agents.

Gel phase formation in dilute triblock copolyelectrolyte complexes

Assembly of oppositely charged triblock copolyelectrolytes into phase-separated gels at low polymer concentrations (<1% by mass) has been observed in scattering experiments and molecular dynamics simulations. Here we show that in contrast to uncharged, amphiphilic block copolymers that form discrete micelles at low concentrations and enter a phase of strongly interacting micelles in a gradual manner with increasing concentration, the formation of a dilute phase of individual micelles is prevented in polyelectrolyte complexation-driven assembly of triblock copolyelectrolytes. Gel phases form and phase separate almost instantaneously on solvation of the copolymers. Furthermore, molecular models of self-assembly demonstrate the presence of oligo-chain aggregates in early stages of copolyelectrolyte assembly, at experimentally unobservable polymer concentrations. Our discoveries contribute to the fundamental understanding of the structure and pathways of complexation-driven assemblies, and raise intriguing prospects for gel formation at extraordinarily low concentrations, with applications in tissue engineering, agriculture, water purification and theranostics.

Reactive Oxygen Species and Glutathione Dual Redox-Responsive Supramolecular Assemblies with Controllable Release Capability

A dual redox and biorelevant triggered supramolecular system is developed through noncovalent supramolecular inclusion interactions between the ferrocene (Fc) modified on camptothecin (CPT) and β-cyclodextrin (β-CD) at the end of methoxy polyethylene glycol (mPEG). With these two segments, a stable noncovalent supramolecular structure, i.e., mPEG-β-CD/Fc-CPT, can be formed, and then self-assembled into micellar structures in water. Interestingly, these supramolecular micelles showed uniform sphere structure, high and constant drug loading content, hyper-fast redox-responsive drug release, and exhibited equal cellular proliferation inhibition toward A549 cancer cells. The cytotoxicity evaluation of mPEG-β-CD also indicated good biocompatibility. In vivo results revealed the mPEG-β-CD/Fc-CPT nanoparticles had higher in vivo efficacy without side effects. It is anticipated this supramolecular complex may serve as a new kind of promising alternative for drug delivery systems.

[Polymer nanoparticles for the delivery of anticancer drug]

Nanocarriers based on polymers are currently attracting much attention to perform efficient drug delivery, especially in cancer therapy. Over the last decades, different kinds of polymer nanoparticulate systems have been developed (e.g., simple, stealth, targeted, stimuli-responsive and prodrug) to propose novel, better and safer cancer therapies. This article will give a brief overview of the different classes of polymer nanoparticles that have been reported and discuss some key achievements deriving from their use in the field of cancer therapy.

Cross-Linked Fluorescent Supramolecular Nanoparticles as Finite Tattoo Pigments with Controllable Intradermal Retention Times

Tattooing has been utilized by the medical community for precisely demarcating anatomic landmarks. This practice is especially important for identifying biopsy sites of nonmelanoma skin cancer (NMSC) due to the long interval (i.e., up to 3 months) between the initial diagnostic biopsy and surgical treatment. Commercially available tattoo pigments possess several issues, which include causing poor cosmesis, being mistaken for a melanocytic lesion, requiring additional removal procedures when no longer desired, and potentially inducing inflammatory responses. The ideal tattoo pigment for labeling of skin biopsy sites for NMSC requires (i) invisibility under ambient light, (ii) fluorescence under a selective light source, (iii) a finite intradermal retention time (ca. 3 months), and (iv) biocompatibility. Herein, we introduce cross-linked fluorescent supramolecular nanoparticles (c-FSNPs) as a "finite tattoo" pigment, with optimized photophysical properties and intradermal retention time to achieve successful in vivo finite tattooing. Fluorescent supramolecular nanoparticles encapsulate a fluorescent conjugated polymer, poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene] (MPS-PPV), into a core via a supramolecular synthetic approach. FSNPs which possess fluorescent properties superior to those of the free MPS-PPV are obtained through a combinatorial screening process. Covalent cross-linking of FSNPs results in micrometer-sized c-FSNPs, which exhibit a size-dependent intradermal retention. The 1456 nm sized c-FSNPs display an ideal intradermal retention time (ca. 3 months) for NMSC lesion labeling, as observed in an in vivo tattoo study. In addition, the c-FSNPs induce undetectable inflammatory responses after tattooing. We believe that the c-FSNPs can serve as a "finite tattoo" pigment to label potential malignant NMSC lesions.

Bioinspired Coordination Micelles Integrating High Stability, Triggered Cargo Release, and Magnetic Resonance Imaging

Catechol-Fe³⁺ coordinated micelles show the potential for achieving on-demand drug delivery and magnetic resonance imaging in a single nanoplatform. Herein, we developed bioinspired coordination-cross-linked amphiphilic polymeric micelles loaded with a model anticancer agent, doxorubicin (Dox). The nanoscale micelles could tolerate substantial dilution to a condition below the critical micelle concentration (9.4 ± 0.3 μg/mL) without sacrificing the nanocarrier integrity due to the catechol-Fe³⁺ coordinated core cross-linking. Under acidic conditions (pH 5.0), the release rate of Dox was significantly faster compared to that at pH 7.4 as a consequence of coordination collapse and particle de-cross-linking. The cell viability study in 4T1 cells showed no toxicity regarding placebo cross-linked micelles. The micelles with improved stability showed a dramatically increased Dox accumulation in tumors and hence the enhanced suppression of tumor growth in a 4T1 tumor-bearing mouse model. The presence of Fe³⁺ endowed the micelles T₁-weighted MRI capability both in vitro and in vivo without the incorporation of traditional toxic paramagnetic contrast agents. The current work presented a simple "three birds with one stone" approach to engineer the robust theranostic nanomedicine platform.

Reduction- and thermo-sensitive core-cross-linked polypeptide hybrid micelles for triggered and intracellular drug release

To address the dynamic instability, premature burst drug release, and lack of intracellular stimuli-sensitivity of current polymeric nanocarriers, a novel type of reduction- and thermo-sensitive core-cross-linked polypeptide hybrid micelle was developed.

Efficient and Targeted Suppression of Human Lung Tumor Xenografts in Mice with Methotrexate Sodium Encapsulated in All-Function-in-One Chimeric Polymersomes

Anisamide-functionalized reversibly crosslinked chimeric polymersomes emerge as an "all-function-in-one" nanoplatform for efficient loading and targeted delivery of methotrexate disodium, a potent water-soluble anticancer drug, to sigma receptor overexpressing H460 nonsmall lung cancer xenografts in vivo, leading to markedly improved tumor-growth inhibition and survival rate and depleted adverse effects as compared to the clinically used formulation (Trexall).

Algorithm for Designing Nanoscale Supramolecular Therapeutics with Increased Anticancer Efficacy

In the chemical world, evolution is mirrored in the origin of nanoscale supramolecular structures from molecular subunits. The complexity of function acquired in a supramolecular system over a molecular subunit can be harnessed in the treatment of cancer. However, the design of supramolecular nanostructures is hindered by a limited atomistic level understanding of interactions between building blocks. Here, we report the development of a computational algorithm, which we term Volvox after the first multicellular organism, that sequentially integrates quantum mechanical energy-state- and force-field-based models with large-scale all-atomistic explicit water molecular dynamics simulations to design stable nanoscale lipidic supramolecular structures. In one example, we demonstrate that Volvox enables the design of a nanoscale taxane supramolecular therapeutic. In another example, we demonstrate that Volvox can be extended to optimizing the ratio of excipients to form a stable nanoscale supramolecular therapeutic. The nanoscale taxane supramolecular therapeutic exerts greater antitumor efficacy than a clinically used taxane in vivo. Volvox can emerge as a powerful tool in the design of nanoscale supramolecular therapeutics for effective treatment of cancer.

Nanoparticle "switch-on" by tetrazine triggering

Small-molecule mediated release of drugs from self-assembled nanoparticles through the mediatory of a Diels–Alder reaction.

This work describes how a small-molecule chemical trigger, reacting through the mediatory of an inverse electron demand Diels–Alder reaction, results in enhanced cellular uptake and selective nanoparticle disintegration and cargo liberation, via gross polymeric morphological alterations. The power of these responsive nanoparticles is demonstrated through encapsulation of the anti-cancer agent doxorubicin and its triggered release, allowing controlled cell death in response to a small-molecule chemical trigger.

Structural Analysis of Hydrophobe-Uptake Micelle of an Amphiphilic Alternating Copolymer in Aqueous Solution

We investigated the structure of the hydrophobe-uptake micelle of an alternating amphiphilic copolymer in aqueous solutions, by combining light scattering and small-angle X-ray scattering (SAXS). When the copolymer micelle includes the hydrophobe (1-dodecanol), the unicore flower micelle transforms into the multicore flower necklace, and the flower necklace is slightly stiffer than the hydrophobe-free flower necklace of the same copolymer. Moreover, the hydrophobe is included not in the hydrophobic core region but in the intermingled region of the hydrophobic group and the loop chain of the unit flower micelle. Therefore, the structure of the hydrophobe-uptake micelle of the amphiphilic alternating copolymer is quite different from that of hydrophobe-uptake spherical micelles of low molar mass surfactants and of amphiphilic block copolymers, where the hydrophobe is included in the hydrophobic region of the micelles.

Plasmonic, Targeted, and Dual Drugs-Loaded Polypeptide Composite Nanoparticles for Synergistic Cocktail Chemotherapy with Photothermal Therapy

To integrate cocktail chemotherapy with photothermal therapy into one biocompatible and biodegradable nanocarrier, the plasmonic, lactose-targeted, and dual anticancer drugs-loaded polypeptide composite nanoparticles were for the first time fabricated under mild conditions. The glyco-PEGylated polypeptide micelles that self-assembled from the lactose (LAC) and PEG grafted polycysteine terpolymer were used as templates to generate the plasmonic composite nanoparticles, as mainly characterized by DLS, TEM, SEM, and XPS. These composite nanoparticles showed a broad and strong near-infrared (NIR) absorption at 650-1100 nm and increased the temperature of phosphate buffer solution by 30.1 °C upon a continuous-wave laser irradiation (808 nm, 5 min, 2 W·cm(-2)), while the same dose of NIR-mediated heating completely killed HepG2 cancer cells in vitro, presenting excellent photothermal properties. Two anticancer drugs, doxorubicin (DOX) and 6-mercaptopurine (6-MP), were loaded into the composite nanoparticles through physical interactions and Au-S bond, respectively. The dual drugs-loaded composite nanoparticles exhibited reduction-sensitive and NIR-triggered cocktail drugs release profiles and trigger-enhanced cytotoxicity. As evidenced by flow cytometry, fluorescence microscopy, and MTT assay, the LAC-coated composite nanoparticles were more internalized by the HepG2 than the HeLa cell line, demonstrating a LAC-targeting enhanced cytotoxicity toward HepG2. The combination cocktail chemo-photothermal therapy produced a lower half maximal inhibitory concentration than cocktail chemotherapy or photothermal therapy alone, displaying a good synergistic antitumor effect.

Development of polymeric micelles for targeting intractable cancers

In relation to recent advances in nanobiotechnologies, cancer-targeted therapy using nano-scaled drug carriers (nanocarriers) has been attracting enormous attention with success in clinical studies. Polymeric micelles, core-shell-type nanoparticles formed through the self-assembly of block copolymers, are one of the most promising nanocarrier, because their critical features such as size, stability, and drug incorporation efficiency and release rate can be modulated by designing the constituent block copolymers. The utilities of polymeric micelles have been reported not only in experimental tumor models in mice but also in clinical studies. In this article, we aim to explain the rationale of designing polymeric micelles for targeting intractable cancers such as pancreatic cancer, glioblastoma, and metastases. Also, we review recent progress in clinical studies on polymeric micelles incorporating anticancer drugs. In addition, we introduce the next generation of polymeric micelles as the platform integrated with smart functionalities such as targetability, environmental sensitivity, and imaging properties. Thus, polymeric micelles can realize safe and effective cancer therapy, and offer tailor-made medicines for individual patients.

A Nanoparticle Platform To Evaluate Bioconjugation and Receptor-Mediated Cell Uptake Using Cross-Linked Polyion Complex Micelles Bearing Antibody Fragments

Targeted nanomedicines are a promising technology for treatment of disease; however, preparation and characterization of well-defined protein-nanoparticle systems remain challenging. Here, we describe a platform technology to prepare antibody binding fragment (Fab)-bearing nanoparticles and an accompanying real-time cell-based assay to determine their cellular uptake compared to monoclonal antibodies (mAbs) and Fabs. The nanoparticle platform was composed of core-cross-linked polyion complex (PIC) micelles prepared from azide-functionalized PEG-b-poly(amino acids), that is, azido-PEG-b-poly(l-lysine) [N3-PEG-b-PLL] and azido-PEG-b-poly(aspartic acid) [N3-PEG-b-PAsp]. These PIC micelles were 30 nm in size and contained approximately 10 polymers per construct. Fabs were derived from an antibody binding the EphA2 receptor expressed on cancer cells and further engineered to contain a reactive cysteine for site-specific attachment and a cleavable His tag for purification from cell culture expression systems. Azide-functionalized micelles and thiol-containing Fab were linked using a heterobifunctional cross-linker (FPM-PEG4-DBCO) that contained a fluorophenyl-maleimide for stable conjugation to Fabs thiols and a strained alkyne (DBCO) group for coupling to micelle azide groups. Analysis of Fab-PIC micelle conjugates by fluorescence correlation spectroscopy, size exclusion chromatography, and UV-vis absorbance determined that each nanoparticle contained 2-3 Fabs. Evaluation of cellular uptake in receptor positive cancer cells by real-time fluorescence microscopy revealed that targeted Fab-PIC micelles achieved higher cell uptake than mAbs and Fabs, demonstrating the utility of this approach to identify targeted nanoparticle constructs with unique cellular internalization properties.

Eradication of CD44-variant positive population in head and neck tumors through controlled intracellular navigation of cisplatin-loaded nanomedicines

Eventual relapse of tumor growth is commonly observed in head and neck cancer patients, following treatment with platinum-based chemotherapies. This occurrence is believed to be related to the failure to eradicate drug resistant, cancer stem cell (CSC) niches, thereby enriching their population in tumors after treatment. In this study, we show that in contrast to free cisplatin (CDDP), the polymer micelle-based nanomedicine incorporating cisplatin (CDDP/m), can eradicate both the undifferentiated cell and the differentiated cancer cell populations within a head and neck tumor model. Immunohistochemistry of treated tumors showed that opposing to CDDP treatment, CDDP/m could reduce tumor growth without concentrating the CSC-like population. We further showed that CDDP/m, but not CDDP, can localize into hypoxic regions, possibly CSC-rich areas, in the tumors, and can overcome their detoxification mechanism based-on high cellular expression of glutathione to successfully deliver Pt to nuclear DNA. Our data suggests CDDP/m to be a replacement for current platinum therapies, for its ability to eradicate both bulk and CSC-like populations, and in turn to prevent recurrence of tumor growth.

Calcium phosphate-based organic-inorganic hybrid nanocarriers with pH-responsive on/off switch for photodynamic therapy

Photodynamic therapy (PDT) is a promising treatment modality for malignant tumors in a light-selective manner. To improve the PDT efficacy, numerous kinds of nanocarriers have been developed to deliver photosensitizers (PSs) selectively into the tumor through leaky tumor-associated vasculature. However, the corresponding prolonged retention of the nanocarrier in the bloodstream may lead to unfavorable photochemical damage to normal tissues such as skin. Here, we report an organic-inorganic hybrid nanocarrier with a pH-responsive on/off switch of PDT efficacy. This hybrid nanocarrier is constructed by hydrothermal synthesis after simple mixing of calcium/phosphate ions, chlorin e6 (amphiphilic low molecular weight PS), and poly(ethylene glycol)-b-poly(aspartic acid) (PEG-PAsp) copolymers in an aqueous solution. The hybrid nanocarrier possesses a calcium phosphate (CaP) core encapsulating the PSs, which is surrounded by a PEG shielding layer. Under physiological conditions (pH 7.4), the nanocarrier suppressed the photochemical activity of PS by lowering the access of oxygen molecules to the incorporated PS, while PDT efficacy was restored in a pH-responsive manner because of the dissolution of CaP and eventual recovery of access between the oxygen and the PS. Owing to this switch, the nanocarrier reduced the photochemical damage in the bloodstream, while it induced effective PDT efficacy inside the tumor cell in response to the acidic conditions of the endo-/lysosomes.

Thailandepsin A-loaded and octreotide-functionalized unimolecular micelles for targeted neuroendocrine cancer therapy

Due to the overexpression of somatostatin receptors in neuroendocrine (NE) cancers, drug nanocarriers conjugated with somatostatin analogs, such as octreotide (OCT), for targeted NE cancer therapy may offer increased therapeutic efficacies and decreased adverse effects. In this study, OCT-functionalized unimolecular micelles were prepared using individual hyperbranched polymer molecules consisting of a hyperbranched polymer core (Boltorn(®) H40) and approximately 25 amphiphilic polylactide-poly(ethlyene glycol) (PLA-PEG) block copolymer arms (H40-PLA-PEG-OCH3/OCT). The resulting micelles, exhibiting a uniform core-shell shape and an average hydrodynamic diameter size of 66 nm, were loaded with thailandepsin-A (TDP-A), a relatively new naturally produced histone deacetylase (HDAC) inhibitor. In vitro studies using flow cytometry and confocal laser scanning microscopy (CLSM) demonstrated that OCT conjugation enhanced the cellular uptake of the unimolecular micelles. Consequently, TDP-A-loaded and OCT-conjugated micelles exhibited the highest cytotoxicity and caused the highest reduction of NE tumor markers. Finally, the in vivo studies on NE cancer bearing nude mice demonstrated that TDP-A-loaded and OCT-conjugated micelles possessed superior anticancer activity in comparison with other TDP-A formulations or drug alone, while showing no detectable systemic toxicity. Thus, these TDP-A-loaded and OCT-conjugated micelles offer a promising approach for targeted NE cancer therapy.

A Theranostic Agent Combining a Two-Photon-Absorbing Photosensitizer for Photodynamic Therapy and a Gadolinium(III) Complex for MRI Detection

The convergent synthesis and characterization of a potential theranostic agent, [DPP-ZnP-GdDOTA](-), which combines a diketopyrrolopyrrole-porphyrin component DPP-ZnP as a two-photon photosensitizer for photodynamic therapy (PDT) with a gadolinium(III) DOTA complex as a magnetic resonance imaging probe, is presented. [DPP-ZnP-GdDOTA](-) has a remarkably high longitudinal water proton relaxivity (19.94 mm(-1)  s(-1) at 20 MHz and 25 °C) for a monohydrated molecular system of this size. The Nuclear Magnetic Relaxation Dispersion (NMRD) profile is characteristic of slow rotation, related to the extended and rigid aromatic units integrated in the molecule and to self-aggregation occurring in aqueous solution. The two-photon properties were examined and large two-photon absorption cross-sections around 1000 GM were determined between 910 and 940 nm in DCM with 1 % pyridine and in DMSO. Furthermore, the new conjugate was able to generate singlet oxygen, with quantum yield of 0.42 and 0.68 in DCM with 1 % pyridine and DMSO, respectively. Cellular studies were also performed. The [DPP-ZnP-GdDOTA](-) conjugate demonstrated low dark toxicity and was able to induce high one-photon and moderate two-photon phototoxicity on cancer cells.

Biodegradable PEI modified complex micelles as gene carriers with tunable gene transfection efficiency for ECs

In recent years, gene therapy has evoked an increasing interest in clinical treatments of coronary diseases because it is a potential strategy to realize rapid endothelialization of artificial vascular grafts. The balance of high transfection efficiency and low cytotoxicity of nonviral gene carriers is an important issue to be solved. In this study, we aim to establish a gene delivery system offering an elegant way to tune the transfection activity and cytotoxicity. Biodegradable complex micelles were prepared from polyethylenimine-b-poly(lactide-co-3(S)-methyl-morpholine-2,5-dione)-b-polyethylenimine (PEI-b-PLMD-b-PEI) and methoxy-poly(ethylene glycol)-b-poly(lactide-co-3(S)-methyl-morpholine-2,5-dione) (mPEG-b-PLMD) copolymers by a co-assembly method. Then the ZNF580 gene plasmid (pDNA) was encapsulated into the complex micelles. The hydrodynamic size and zeta potential of these complex micelles and micelles/pDNA complexes indicated that they were feasible for use in cellular uptake and gene transfection. As expected, the transfection efficiency and cytotoxicity of these micelles/pDNA complexes could be conveniently tuned by changing the mass ratio of mPEG-b-PLMD to PEI-b-PLMD-b-PEI (3/1, 2/2, 1/3 and 0/4) in the mixed mPEG/PEI shell. The transfection efficiency increased as the mass ratio of mPEG-b-PLMD/PEI-b-PLMD-b-PEI decreased from 3/1 to 0/4, while the cytotoxicity showed an opposite tendency. Moreover, ZNF580 protein expression determined by Western blot analysis and the migration of transfected endothelial cells (ECs) by wound healing assay were consistent with the result of transfection efficiency. All these results indicated that the co-assembled complex micelles could act as suitable gene carriers with tunable gene transfection efficiency and cytotoxicity, which should have great potential for the transfection of vascular ECs.

Oxidation and temperature dual responsive polymers based on phenylboronic acid and N-isopropylacrylamide motifs

Oxidation and temperature dual responsive copolymers using ROS as a target for drug delivery have been demonstrated.

The use of electrostatic association for rapid RAFT synthesis of histamine polyelectrolyte in aqueous solutions at and below 25 °C

Electrostatic association for rapid and quantitative synthesis of well-defined polyelectrolytes in dilute aqueous solutions at and below 25 °C.

Active Tumor Permeation and Uptake of Surface Charge-Switchable Theranostic Nanoparticles for Imaging-Guided Photothermal/Chemo Combinatorial Therapy

To significantly promote tumor uptake and penetration of therapeutics, a nanovehicle system comprising poly(lactic-co-glycolic acid) (PLGA) as the hydrophobic cores coated with pH-responsive N-acetyl histidine modified D-α-tocopheryl polyethylene glycol succinate (NAcHis-TPGS) is developed in this work. The nanocarriers with switchable surface charges in response to tumor extracellular acidity (pH_e) were capable of selectively co-delivering indocyanine green (ICG), a photothermal agent, and doxorubicin (DOX), a chemotherapy drug, to tumor sites. The in vitro cellular uptake of ICG/DOX-loaded nanoparticles by cancer cells and macrophages was significantly promoted in weak acidic environments due to the increased protonation of the NAcHis moieties. The results of in vivo and ex vivo biodistribution studies demonstrated that upon intravenous injection the theranostic nanoparticles were substantially accumulated in TRAMP-C1 solid tumor of tumor-bearing mice. Immunohistochemical examination of tumor sections confirmed the active permeation of the nanoparticles into deep tumor hypoxia due to their small size, pH_e-induced near neutral surface, and the additional hitchhiking transport via tumor-associated macrophages. The prominent imaging-guided photothermal therapy of ICG/DOX-loaded nanoparticles after tumor accumulation induced extensive tumor tissue/vessel ablation, which further promoted their extravasation and DOX tumor permeation, thus effectively suppressing tumor growth.

An autoreduction method to prepare plasmonic gold-embedded polypeptide micelles for synergistic chemo-photothermal therapy

An autoreduction method was introduced to prepare plasmonic gold-embedded polypeptide micelles, opening up a new avenue for the development of anticancer nanotherapeutics with synergistic chemo-photothermal effects.

A polypeptide micelle template method to prepare polydopamine composite nanoparticles for synergistic photothermal–chemotherapy

A polypeptide micelle template method was, for the first time, developed to fabricate polydopamine nanocomposites for the synergistic photothermal–chemotherapy of cancer.