Amphiphilic Homopolymer Vesicles as Unique Nano-Carriers for Cancer Therapy

Solution Self-Assembly of Amphiphilic Tadpole-like Giant Molecules Constructed by Monotethering Diblock Copolymer Chain onto a Nanoparticle

The self-assembly behavior of a tadpole-like giant molecule (TGM) constructed from a hydrophobic nanoparticle (NP) monotethered by a single amphiphilic AB diblock copolymer chain was investigated by combining self-consistent field theory and density functional theory in solution. The effects of the hydrophobicities of the B blocks and NPs (i.e., solvent properties) on the self-assembly behavior of the TGMs were investigated in the cases of weak and strong intramolecular interactions (i.e., incompatibilities) between the components of giant molecules, respectively. Besides conventional ordered aggregates (such as spheres, rings, and vesicles) with hydrophobic B-cores covered by NP shells, several aggregates with novel hierarchical structures, including vesicles with NP-inserted hydrophobic walls, bead-string-like micelles, and long cylindrical micelles with NP bumps, were obtained by tuning the solvent properties under different intramolecular interactions. Noteworthy that the simulation results show that the arrangement of the NP bumps on the long cylindrical micelles may have a certain degree of helicity, which means that these micelles may have some unique electromagnetic features such as circular dichroism. Phase diagrams as a function of the hydrophobicities of the B blocks and NPs were constructed to show the formation conditions of these novel structures. These findings can not only offer new insights into understanding of the self-assembly behavior of the TGM in solution but also provide useful guidance for simple and efficient regulation of the morphology, as well as the NP distribution and arrangement of the ordered aggregates in experiments.

Intelligent design of polymersomes for antibacterial and anticancer applications

Polymersomes (or polymer vesicles) have attracted much attention for biomedical applications in recent years because their lumen can be used for drug delivery and their coronas and membrane can be modified with a variety of functional groups. Thus, polymersomes are very suitable for improved antibacterial and anticancer therapy. This review mainly highlighted recent advances in the synthetic protocols and design principles of intelligent antibacterial and anticancer polymersomes. Antibacterial polymersomes are divided into three categories: polymersomes as antibiotic nanocarriers, intrinsically antibacterial polymersomes, and antibacterial polymersomes with supplementary means including photothermal and photodynamic therapy. Similarly, the anticancer polymersomes are divided into two categories: polymersomes-based delivery systems and anticancer polymersomes with supplementary means. In addition, the bilateral relationship between bacteria and cancer is addressed, since more and more evidences show that bacteria may cause cancer or promote cancer progression. Finally, prospective on next-generation antibacterial and anticancer polymersomes are discussed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Lipid-Based Structures.

Non-Clinical Investigation of Tuberculosis Drugs: Conjugated Norbornene- Based Nanocarriers Toxic Impacts on Zebrafish

INTRODUCTION:

Rifampicin conjugated (R-CP), and rifampicin -isoniazid dual conjugated (RI-CP) norbornene-derived nanocarriers are newly designed for pH stimuli-responsive delivery of tuberculosis (TB) drugs. Its biosafety level is yet to be well established.

OBJECTIVES:

To assess the impacts of the nanocarriers on liver cells using zebrafish animal model and human liver cell line model (HepG2).

METHODS:

Initially, lethal dose concentration for the norbornene-derived nanocarrier systems in zebrafish was determined. The toxic effects were analysed at the sub-lethal drug concentration by histopathological study, total GSH level, gene expression and DNA damage in zebrafish liver cells. Fish erythrocyte nuclear abnormalities were also evaluated. Cell viability and oxidative stress level (ROS generation) after exposure to the nanoconjugates was determined using HepG2 cell in the in vitro study.

RESULTS:

In vivo studies of both R-CP and RI-CP showed 100% mortality at 96 hours for exposure concentration >100mg/l and showed toxic changes in zebrafish liver histology, GSH, and DNA damage levels. A noticeable upregulated PXR, CYP3A and cyp2p6 genes was observed in RI-CP exposure than in RIF or R-CP molecules. The in vitro study revealed a dose-dependent effect on cell viability and ROS generation for RIF, R-CP and RI-CP exposures in HepG2 cells.

CONCLUSION:

The current study reports that the rifampicin conjugated (R-CP) and rifampicin-isoniazid conjugated (RI-CP) norbornene derived nanocarriers exhibit enhanced toxic responses in both adult zebrafish and HepG2 cells. The pH-sensitive norbornene derived nanocarriers on conjugation with different drugs exhibited varied impacts on hepatic cells. Hence the present investigation recommends a complete metabolomics analysis and norbornene carrier-drug interaction study to be performed for each drug conjugated norbornene nanocarrier to ensure its biosafety.

Advanced Nanomaterials-Assisted Cell Cryopreservation: A Mini Review

Cell cryopreservation is of vital significance both for transporting and storing cells before experimental/clinical use. Cryoprotectants (CPAs) are necessary additives in the preserving medium in cryopreservation, preventing cells from freeze-thaw injuries. Traditional organic solvents have been widely used in cell cryopreservation for decades. Given the obvious damage to cells due to their undesirable cytotoxicity and the burdensome post-thaw washing cycles before use, traditional CPAs are more and more likely to be replaced by modern ones with lower toxicity, less processing, and higher efficiency. As materials science thrives, nanomaterials are emerging to serve as potent vehicles for delivering nontoxic CPAs or inherent CPAs comparable to or even superior to conventional ones. This review will introduce some advanced nanomaterials (e.g., organic/inorganic nanoCPAs, nanodelivery systems) utilized for cell cryopreservation, providing broader insights into this developing field.

Self-assembly behavior of oligo(ethylene glycol) substituted polycaprolactone homopolymers

In this work, non-ionic amphiphilic oligo(ethylene glycol)-substituted polycaprolactone homopolymers readily self-assembled to form micelles in a polar environment, which allowed the encapsulation of a hydrophobic molecule.

Multichain adsorption at fluid interfaces: Amphiphilic homopolymers vs copolymers

HYPOTHESIS

At selective liquid-liquid interface, amphiphilic homopolymers, having groups with different affinity for the liquids in each monomer unit, would demonstrate higher occupation of the interfacial layer than copolymers with various distributions of groups and be advantageous as interface stabilizers.

EXPERIMENTS

By means of Langevin dynamics computer simulation, conformations of multiple chains of amphiphilic macromolecules adsorbed at the liquid-liquid interface were studied. Monomer units having different affinity for the liquids were distributed variously along the polymer chains. Homopolymers, amphiphilic at the level of an individual monomer unit, and copolymers with random, altermating and multiblock distribution of groups were considered. The surface coverage, structure of the layer, and spatial distribution of monomer units were investigated depending on the polymer concentration.

FINDINGS

Compared to copolymers with random, alternating and multiblock distributions of the groups, the interfacial layer concentration of amphiphilic homopolymer is about 1.5 times higher, the adsorbed layer is remarkably thinner, has membrane-like structure and is asymmetric with respect to interface boundary. Also, the adsorbed amphiphilic homopolymers form fewer loops and tails, most located on one side of the interface. This combination of properties is promising for practical application in modern self-assembling molecular devices.

Dual Biochemically Breakable Drug Carriers from Programmed Telechelic Homopolymers

Well-defined hydrophilic telechelic dibromo poly(triethylene glycol monomethyl ether acrylate)s were prepared by single-electron transfer living radical polymerization employing a hydrophobic difunctional initiator containing acetal and disulfide linkages. Although the resulting homopolymers have low hydrophobic contents (<8.5 wt % of the entire structure), they are able to self-assemble in water into nanoscale micellelike particles via chain folding. Acetal and disulfide linkages were demonstrated to be "keystone" units for their dual stimuli-responsive behavior under biochemically relevant conditions. Their site-selective middle-chain cleavage under both acidic pH and reductive conditions splits the homopolymer into two equal-sized fragments and results in the breakdown of the nanoassemblies. The drug loading/delivery potential of these nanoparticles was investigated using curcumine combining in vitro drug release, cytotoxicity, and cellular uptake studies with human cancer cell lines (HT-29 and HeLa). Importantly, this strategy may be extended to prepare innovative nanoplatforms based on hydrophilic homopolymers or random copolymers for intelligent drug delivery.

Factors affecting the morphology of some organic and inorganic nanostructures for drug delivery: characterization, modifications, and toxicological perspectives

Introduction: In this review, we aim to highlight the impact of various processes and formulation variables influencing the characteristics of certain surfactant-based nanoconstructs for drug delivery. Areas covered: The review includes the discussion on processing parameters for the preparation of nanoconstructs, especially those made up of surfactants. Articles published in last 15 years (437) were reviewed, 381 articles were selected for data review and most appropriate articles (215) were included in article. Effect of variables such as surfactant concentration and type, membrane additives, temperature, and pH-dependent transitions on morphology has been highlighted along with effect of shape on nanoparticle uptake by cells. Various characterization techniques explored for these nanostructures with respect to size, morphology, lamellarity, distribution, etc., and a separate section on polymeric vesicles and the influence of block copolymers, type of block copolymer, control of block length, interaction of multiple block copolymers on the structure of polymersomes and chimeric nanostructures have been discussed. Finally, applications, modification, degradation, and toxicological aspects of these drug delivery systems have been highlighted. Expert opinion: Parameters influencing the morphology of micelles and vesicles can directly or indirectly affect the efficacy of small molecule cellular internalization as well as uptake in the case of biologicals.[Figure: see text].

pH-Responsive Micellar Nanoassemblies from Water-Soluble Telechelic Homopolymers Endcoding Acid-Labile Middle-Chain Groups in Their Hydrophobic Sequence-Defined Initiator Residue

A middle-chain cleavable telechelic poly(oligoethylene glycol) methyl ether acrylate) (MCCT-POEGA-Br) was synthesized by single-electron transfer living radical polymerization (SET-LRP) initiated from an acetal-containing hydrophobic sequence-defined difunctional initiator. In aqueous medium, above a certain concentration, this hydrophilic homopolymer self-assembled into nanogel-like large micelles that exhibit an encapsulating capacity for both hydrophobic and hydrophilic cargo. The sequence-defined cleavage pattern encoded in the initiator residue allowed precise middle-chain cleavage, leading to quantitative disassembly of the corresponding nanoobjects. Dye release studies performed in an acidic environment demonstrated the potential of this new design concept in the preparation of pH-responsive nanocarriers. In addition, fluorescently tagged nanoassemblies could also be obtained via the thio-bromo "click" modification of MCCT-POEGA-Br prior to self-assembly. This strategy may provide facile access to a diversity of multistimuli-responsive nanocarriers based on commercially available hydrophilic monomers and sequence-defined difunctional initiators synthesized by this simple design strategy.

Barbiturate derived amphiphilic homopolymers: synthesis, characterization, self-assembly and anticancer drug delivery

Aim: Our aim was to synthesis and characterization of amphiphilic norbornene-derived thiobarbiturate homopolymers (NDTH 1-4) for drug delivery. Methods: Ring-opening metathesis polymerization technique was used to prepare a series of homopolymers. The hydrophobicity is introduced by increasing the number of carbon chains ([-CH₂-]_n; n = 1, 2, 3 & 4) in between norbornene backbone and thiobarbiturate species. Results: These vesicular aggregates have been used as anticancer Doxorubicin drug delivery vehicles at the acidic (5.5) and physiological (7.4) pHs. Confocal laser-scanning microscopy has demonstrated that the drug-loaded vesicles are easily internalized into living cells. Conclusion: Amphiphilic norbornene-derived thiobarbiturate homopolymer assemblies showed efficient nanocarrier for effective anticancer drug delivery.

Programmed supramolecular nanoassemblies: enhanced serum stability and cell specific triggered release of anti-cancer drugs

A bolaamphiphilic cross-linked nanoassembly endowed with pH responsive degradation features has been designed and fabricated for stable noncovalent guest encapsulation and controlled release. The self-assembled bolaamphiphile is utilized to prepare cross-linked nanoassemblies to further stabilize the noncovalent guest encapsulation at a concentration below its critical aggregation concentration (CAC) in a large volume of water or serum for drug delivery applications. Thus, this system can simultaneously address premature drug release and safety issues. The nanoassemblies integrated with a β-thioester linker, which can be hydrolyzed selectively under mildly acidic conditions (pH ∼ 5.3) at a slow rate, thus enable controlled release of guest molecules. Biological evaluation revealed that doxorubicin loaded cross-linked nanoassemblies (CNs-DOX) are nontoxic to normal cells such as HEK-293 or PBMC, but in contrast, showed a robust apoptotic effect on colon cancer cells, HCT-116, indicating excellent specificity. Thus, the fabrication reproducibility, robust stability, triggered drug release and cell selective toxicity behavior make this small molecular system very promising in the field of chemotherapeutic applications.

Sequential Nucleophilic "Click" Reactions for Functional Amphiphilic Homopolymers

Amphiphilic homopolymers with high densities of functional groups are synthetically challenging. Thiol-yne nucleophilic click reactions have been investigated to introduce multiple functional groups in polymers with high density. An electron deficient alkyne group bearing methacrylate monomer was polymerized using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Subsequently, the electron deficient alkyne group on polymer side chain was readily reacted with a thiol reagent using triethylamine (TEA) as the organocatalyst. This reaction was found to be very efficient under mild conditions. The resultant homopolymer bearing thiol vinyl ether functional groups could perform a second thiol addition with a stronger base, such as triazabicyclodecene (TBD), to prepare multifunctional homopolymers. This stepwise addition process was monitored by 1H NMR as well as gel permeation chromatography. The fidelity of this method was demonstrated by attaching four different functionalities, including both hydrophobic and hydrophilic moieties. Furthermore, these dual functionalized polymers bearing dithio-acetal groups are sensitive to reactive oxygen species (ROS), which compromises the host-guest properties of the assembly in response to this stimulus. The ROS responsive polymers reported here may have potential use in therapeutic delivery.

Evolution of diverse higher-order membrane structures of block copolymer vesicles

An evolutionary route to polymer vesicles with diverse higher-order membrane structures has been discovered.

Polymer Vesicles: Modular Platforms for Cancer Theranostics

As an emerging field that is receiving an increasing amount of interest, theranostics is becoming increasingly important in the field of nanomedicine. Among the various smart platforms that have been proposed for use in theranostics, polymer vesicles (or polymersomes) are among the most promising candidates for integration of designated functionalities and modalities. Here, a brief summary of typical theranostic platforms is presented with a focus on modular polymer vesicles. To highlight modularity, the different methodologies for designing therapeutic and diagnostic modules are classified and current examples of theranostic vesicles that excel in both performance and design principle are provided. Finally, future prospects for theranostic polymer vesicles that can be readily prepared with functional modules are proposed. Overall, theranostic polymer vesicles with modular modalities and functions are more promising in nanomedicine than simply being "over-engineered".

Metal assisted self-assembled rod like nanostructures for effective cellular internalization

This work describes a metal assisted self-assembled rod like nanostructure which can be used for the delivery of therapeutic agents.

Synthesis of Norbornene Derived Helical Copolymer by Simple Molecular Marriage Approach to Produce Smart Nanocarrier

A novel library of norbornene derived helical copolymer has been synthesized through the coupling of two homopolymers via Molecular Marriage Approach. The helicity is governed by the non-covalent interactions like hydrogen bonding, π-π stacking and the influence of hydrophobic and hydrophilic motifs. The detailed characterization of the copolymer (Copoly 1) has been provided and the super structures are confirmed through dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The observed size of the aggregates was about 200 nm. The density functional theory (DFT) is favorably supported for the formation of proposed structure of Copoly 1. Circular dichroism (CD) measurement has confirmed the one handed helical structure of the copolymer. Reservoir capability of this pH responsive polymer (Copoly 1) to encapsulate anti-cancer drug doxorubicin (DOX) warrants its potential applications in the field of bio-medical sciences.

Phosphonium-Functionalized Polymer Micelles with Intrinsic Antibacterial Activity

New approaches to treat bacterial infections are badly needed to address the increasing problem of antibiotic resistance. This study explores phosphonium-functionalized block copolymer micelles as intrinsically antibacterial polymer assemblies. Phosphonium cations with varying alkyl lengths were conjugated to the terminus of a poly(ethylene oxide)-polycaprolactone block copolymer, and the phosphonium-functionalized block copolymers were self-assembled to form micelles in aqueous solution. The size, morphology, and ζ-potential of the assemblies were studied, and their abilities to kill Escherichia coli and Staphylococcus aureus were evaluated. It was found that the minimum bactericidal concentration depended on the phosphonium alkyl chain length, and different trends were observed for Gram-negative and Gram-positive bacteria. The most active assemblies exhibited no hemolysis of red blood cells above the bactericidal concentrations, indicating that they can selectively disrupt the membranes of bacteria. Furthermore, it was possible to encapsulate and release the antibiotic tetracycline using the assemblies, providing a potential multimechanistic approach to bacterial killing.

In vitro HER2 protein-induced affinity dissociation of carbon nanotube-wrapped anti-HER2 aptamers for HER2 protein detection

A new in vitro assay was developed to detect human epidermal growth factor receptor 2 (HER2) protein, based on affinity dissociation of carbon nanotube (CNT)-wrapped anti-HER2 ssDNA aptamers. First, we selected an anti-HER2 ssDNA aptamer (H2) using an in vitro serial evolution of ligands by an exponential enrichment (SELEX) process. Then the fluorescently labelled H2 ssDNAs were tightly packed on CNTs that had previously been coupled with magnetic microbeads (MBs), forming MB-CNT-H2 hybrids. The loading capacity of these MB-CNTs heterostructures (2.8 × 10(8)) was determined to be 0.025 to 3.125 μM of H2. HER2 protein-induced H2 dissociation occurred from MB-CNT-H2 hybrids, which was specifically induced by the target HER2 protein, with a dissociation constant (Kd) of 270 nM. The stoichiometric affinity dissociation ratio with respect to H2-to-HER2 protein was shown to be approximately 1 : 1. Our results demonstrated that the developed assay can be an effective approach in detecting native forms of disease biomarkers in free solutions or in biological samples, for accurate diagnosis.

Self-organization in water of well-defined amphiphilic poly(vinyl acetate)-b-poly(vinyl alcohol) diblock copolymers

Self-organization of well-defined poly(vinyl acetate)-b-poly(vinyl alcohol) (PVAc-b-PVA) amphiphilic diblock copolymers with different hydrophilic block sizes was reported.

Self-assemblies of amphiphilic homopolymers: synthesis, morphology studies and biomedical applications

The need for a simplified access to supramolecular assemblies with enhanced tenability has led to the development of amphiphilic homopolymers (APHPs). This review highlights recent advances and future trends in APHP design, self-assembly, and biomedical applications.

Increased bioavailability of rifampicin from stimuli-responsive smart nano carrier

Stimuli responsive polymeric nanocarrier (RCOP-2) functionalized with frontline antituberculosis drug (Rifampicin) is demonstrated for sustained release. Bioavailability of Rifampicin is taken care of by conjugating this drug through a acylhydrazine linker to the polymeric backbone. The poly(ethylene glycol) structural motif is introduced in the copolymer architecture for water solubility. Releasing retinal along with Rifampicin is hypothesized to reduce the risk of side effects due to Rifampicin. The self-assembly of RCOP-2, due to the amphiphilicity present in the copolymer, is explored in detail. The pH responsiveness of RCOP-2 is demonstrated in mild acidic environment as well as in cell lines. The 4T cell line, due to its acidic nature, shows time-dependent cellular internalization. On the basis of the results, our unique design is expected to provide an increased bioavalaibility of Rifampicin with reduced side effects. From the flow cytometry results on A549 cell lines, it is clear that the newly designed copolymer RCOP-2 can internalize efficiently and serve as an effective Rifampicin delivery system.

Environmentally responsive polymeric materials: effect of the topological structure on self-assembly

A novel amphiphilic homopolymer (PAGC8), containing two hydrophilic head groups and double hydrophobic tails in each repeat unit, has been prepared by solution polymerization and named as "a geminized amphiphilic homopolymer" in this paper, which is capable of self-assembling into various nanoobjects depending on the solution concentration and solvent properties. Characterization of the self-assembly behaviors was carried out by steady-state fluorescence, transmission electron microscopy and nuclear magnetic resonance techniques. Particular emphasis was dedicated to the environmental responsiveness of the assemblies. The morphologies were observed to transform from micelle-type to vesicles on adding a certain amount of ethanol. It is noteworthy that the assemblies were able to trap hydrophilic (rhodamine B) and hydrophobic (Sudan Red) molecules. Subsequently different nanoobjects were found after the encapsulation. To probe the effect of the topological structure on the self-assembly behaviors, the properties of an additional homopolymer with single charge pendant architecture on the backbone were investigated for comparison. Significant differences in structure between the two architectures brought out remarkable variations in aggregates, which were non-responsive to the solvent environment, or encapsulation of molecules. Based on the experimental results, we proposed a possible mechanism of the morphological transitions of the assemblies.

Nanostructural systems developed with positive charge generation to drug delivery

The surface charge of a nanostructure plays a critical role in modulating blood circulation time, nanostructure-cell interaction, and intracellular events. It is unfavorable to have positive charges on the nanostructure surface before arriving at the disease site because positively charged nanostructures interact strongly with blood components, resulting in rapid clearance from the blood, and suboptimal targeted accumulation at the tumor site. Once at the tumor site, however, the positive charge on the nanostructure surface accelerates uptake by tumor cells and promotes the release of payloads from the lysosomes to the cytosol or nucleus inside cells. Thus, the ideal nanocarrier systems for drug delivery would maintain a neutral or negatively charged surface during blood circulation but would then generate a positive surface charge after accumulation at the tumor site or inside the cancer cells. This Progress Report focuses on the design and application of various neutral or negatively charged nanostructures that can generate a positive charge in response to the tumor microenvironment or an external stimulus.

Multifunctional homopolymer vesicles for facile immobilization of gold nanoparticles and effective water remediation

Homopolymers have been considered as a nonideal building block for creating well-defined nanostructures due to their fuzzy boundary between hydrophobic and hydrophilic moieties. However, this unique fuzzy boundary may provide some opportunities for fabricating functional nanomaterials. Presented in this paper is a pH-responsive multifunctional homopolymer vesicle based on poly[2-hydroxy-3-(naphthalen-1-ylamino)propyl methacrylate] (PHNA). This vesicle is confirmed to be an excellent supporter for gold nanoparticles (AuNPs) to facilitate the reduction reaction of 4-nitrophenol (4-NP). The pH-responsive vesicle membrane favors the effective embedding and full immobilization of AuNPs because it is kinetically frozen under neutral and basic environments, preventing AuNPs from aggregation. Meanwhile, there is a synergistic effect between the AuNPs and the supporter (PHNA vesicle). Due to the π-π interaction between the naphthalene pendants in every repeat unit of PHNA and the extra aromatic compounds, a substrate-rich (high concentration of 4-NP) microenvironment can be created around AuNPs, which can dramatically accelerate the AuNPs-catalyzed reactions. In addition, we proposed a method for more accurately determining the membrane thickness of rigid polymer vesicles from TEM images based on "stack-up" vesicles, which may overturn the measuring method commonly used by far. Moreover, proof-of-concept studies showed that those homopolymer vesicles may be used as a powerful adsorbent for effective water remediation to remove trace carcinogenic organic pollutants such as polycyclic aromatic hydrocarbons to below parts per billion (ppb) level at a very fast rate based on the π-π interaction between the naphthalene pendants in PHNA vesicle and polycyclic aromatic hydrocarbons. Overall, this multifunctional homopolymer vesicle provides an alternative insight on preparing effective recyclable AuNPs-decorated nanoreactor and powerful water remediation adsorbent.

Magnetic norbornene polymer as multiresponsive nanocarrier for site specific cancer therapy

A site-specific, stimuli-responsive nanocarrier has been synthesized by conjugating folate, magnetic particles and doxorubicin to the backbone of norbornene polymer. Monomers, namely, cis-5-norbornene-6-(diethoxyphosphoryl)hexanote (mono 1), norbornene grafted poly(ethyleneglycol)-folate (mono 2), and norbornene derived doxorubicin (mono 3) are carefully designed to demonstrate the smart nanorcarrier capabilities. The synthesis and complete characterization of all three monomers are elaborately discussed. Their copolymerization is done by controlled/living ring-opening metathesis polymerization (ROMP) to get the triblock copolymer PHOS-FOL-DOX. NMR spectroscopy and gel permeation chromatography confirm the formation of the triblock copolymer, while FT-IR spectroscopy, thermogravimetric analysis, along with transmission electron microscope confirm the anchoring of iron particle (Fe3O4) to the PHOS-FOL-DOX. Drug release profile shows the importance of having the hydrazone linker that helps to release the drug exactly at the mild acidic conditions resembling the pH of the cancerous cells. The newly designed nanocarrier shows greater internalization (about 8 times) due to magnetic field. Also, increased intracellular DOX release is observed due to the folate receptor. From these results, it is clear that PHOS-FOL-DOX has the potential to act as a smart nanoreservoir with the magnetic field guidance, folate receptor targeting, and finally pH stimulation.

Hierarchical Self-Assembly of Amphiphilic Homopolymer into Unique Superstructures

Supramolecular forces influence the morphologies of self-assemblies. Herein, self-assembled structures of an amphiphilic, norbornene-derived thiobarbiturate homopolymers (p-NTB) are discussed. The newly designed hompolymer shows self-assembled rod-like structures in tetrahydrofuran (THF) solvent. Formation of the rods are governed by hydrogen bonding motifs and amphiphilicity found in the molecular architecture. The solvent polarity controls their organization into cube-like and sphere-like structures at the next length scale. Encapsulation studies of hydrophobic magnetic particles as well as drug molecules into these superstructures demonstrate a novel route to fabricate multifunctional cube-like and sphere-like aggregates.

Stimuli responsive nanocarrier for an effective delivery of multi-frontline tuberculosis drugs

We prepare stimuli responsive polymeric nanocarrier, RCP-2 to demonstrate the high drug content as well as controlled release in a systematic manner.

Decoration of homopolymer vesicles by antibacterial ultrafine silver nanoparticles

Silver nanoparticles have been successfully decorated on the poly(2-(2-ethoxyethoxy)ethyl acrylate) (PEEA) homopolymer vesicles, exhibiting good antibacterial activity against both Gram-positive and Gram-negative bacteria.

How does a tiny terminal alkynyl end group drive fully hydrophilic homopolymers to self-assemble into multicompartment vesicles and flower-like complex particles?

We report an unusual self-assembly behavior driven by a tiny terminal alkynyl end group in fully hydrophilic homopolymers which form multicompartment vesicles and flower-like nanoparticles in aqueous solution.

Antibacterial Polypeptide-Grafted Chitosan-Based Nanocapsules As an "Armed" Carrier of Anticancer and Antiepileptic Drugs

Antibacterial polypeptides as ancient immune defense systems are effective against bacteria. Here we report a novel kind of "armed" carrier: an antibacterial polypeptide-grafted chitosan-based nanocapsule with an excellent antibacterial efficacy against both Gram-positive and Gram-negative bacteria. This nanocapsule also has excellent blood compatibility and low cytotoxicity. Patients after tumor surgery may benefit from this "armed" carrier because it is highly anti-inflammation and is able to deliver anticancer and antiepileptic drugs simultaneously.

Enhancing cell nucleus accumulation and DNA cleavage activity of anti-cancer drug via graphene quantum dots

Graphene quantum dots (GQDs) maintain the intrinsic layered structural motif of graphene but with smaller lateral size and abundant periphery carboxylic groups, and are more compatible with biological system, thus are promising nanomaterials for therapeutic applications. Here we show that GQDs have a superb ability in drug delivery and anti-cancer activity boost without any pre-modification due to their unique structural properties. They could efficiently deliver doxorubicin (DOX) to the nucleus through DOX/GQD conjugates, because the conjugates assume different cellular and nuclear internalization pathways comparing to free DOX. Also, the conjugates could enhance DNA cleavage activity of DOX markedly. This enhancement combining with efficient nuclear delivery improved cytotoxicity of DOX dramatically. Furthermore, the DOX/GQD conjugates could also increase the nuclear uptake and cytotoxicity of DOX to drug-resistant cancer cells indicating that the conjugates may be capable to increase chemotherapy efficacy of anti-cancer drugs that are suboptimal due to the drug resistance.