Bioresponsive polymer coated drug nanorods for breast cancer treatment

Hierarchical colloidosomes self-assembled from block copolymer micelles via emulsion interfacial confinement

Hierarchical self-assembly of polymeric building blocks into high-level colloidosomes is desirable to not only design novel nanostructures but also fabricate the complex artificial materials across many length scales with multifunctionality. Although great progress has been made in the designing the hierarchical colloidosomes, the fabrication of polymeric colloidosomes self-assembled from block copolymer (BCP) colloidal nanoparticles still remains challenge. Here, we report the fabrication of the hierarchical polymeric colloidosomes with typical hollow internal structures self-assembled from the polystyrene-block-poly (2-vinyl pyridine) (PS-b-P2VP) BCP spherical micelles through the emulsion interfacial confinement, which is constructed through the water-in-1-butanol emulsion system. Moreover, the hierarchical colloidosomes can disassemble into the original uniform spherical micelles under the acid aqueous solution, indicating that the colloidosomes possess good pH stimuli-responsibility. Finally, the stability of the colloidosomes can be greatly improved by cross-linking the P2VP corona of original spherical micelles, offering the effective templates for construction of the multifunctional materials. This finding provides a simple yet effective method for the fabrication of the hierarchical colloidosomes from the BCP building blocks.

Combination inhibition of triple-negative breast cancer cell growth with CD36 siRNA-loaded DNA nanoprism and genistein

Currently, a single treatment is less effective for triple-negative breast cancer (TNBC) therapy. Additionally, there are some limitations to the use of siRNA alone as a new method to treat breast cancer, such as its effective delivery into cells. In this study, we proposed a strategy that combines a siRNA-loaded DNA nanostructure and genistein for TNBC therapy. Both CD36 siRNA-loaded self-assembled DNA nanoprisms (NP-siCD36) and genistein knocked down CD36, resulting in enhanced anticancer efficacy through phosphorylation of the p38 MAPK pathway.In vitrostudies showed that combination therapy could effectively enhance cell apoptosis and reduce cell proliferation, achieving an antitumor effect in TNBC cells. The current study suggests that NP-siCD36 combined with genistein might be a promising strategy for breast cancer and treatment.

Antibody-drug nanoparticle induces synergistic treatment efficacies in HER2 positive breast cancer cells

Chemotherapeutic drugs suffer from non-specific binding, undesired toxicity, and poor blood circulation which contribute to poor therapeutic efficacy. In this study, antibody–drug nanoparticles (ADNs) are engineered by synthesizing pure anti-cancer drug nanorods (NRs) in the core of nanoparticles with a therapeutic monoclonal antibody, Trastuzumab on the surface of NRs for specific targeting and synergistic treatments of human epidermal growth factor receptor 2 (HER2) positive breast cancer cells. ADNs were designed by first synthesizing ~ 95 nm diameter × ~ 500 nm long paclitaxel (PTX) NRs using the nanoprecipitation method. The surface of PTXNRs was functionalized at 2′ OH nucleophilic site using carbonyldiimidazole and conjugated to TTZ through the lysine residue interaction forming PTXNR-TTZ conjugates (ADNs). The size, shape, and surface charge of ADNs were characterized using scanning electron microscopy (SEM), SEM, and zeta potential, respectively. Using fluorophore labeling and response surface analysis, the percentage conjugation efficiency was found > 95% with a PTX to TTZ mass ratio of 4 (molar ratio ≈ 682). In vitro therapeutic efficiency of PTXNR-TTZ was evaluated in two HER2 positive breast cancer cell lines: BT-474 and SK-BR-3, and a HER2 negative MDA-MB-231 breast cancer cell using MTT assay. PTXNR-TTZ inhibited > 80% of BT-474 and SK-BR-3 cells at a higher efficiency than individual PTX and TTZ treatments alone after 72 h. A combination index analysis indicated a synergistic combination of PTXNR-TTZ compared with the doses of single-drug treatment. Relatively lower cytotoxicity was observed in MCF-10A human breast epithelial cell control. The molecular mechanisms of PTXNR-TTZ were investigated using cell cycle and Western blot analyses. The cell cycle analysis showed PTXNR-TTZ arrested > 80% of BT-474 breast cancer cells in the G2/M phase, while > 70% of untreated cells were found in the G0/G1 phase indicating that G2/M arrest induced apoptosis. A similar percentage of G2/M arrested cells was found to induce caspase-dependent apoptosis in PTXNR-TTZ treated BT-474 cells as revealed using Western blot analysis. PTXNR-TTZ treated BT-474 cells showed ~ 1.3, 1.4, and 1.6-fold higher expressions of cleaved caspase-9, cytochrome C, and cleaved caspase-3, respectively than untreated cells, indicating up-regulation of caspase-dependent activation of apoptotic pathways. The PTXNR-TTZ ADN represents a novel nanoparticle design that holds promise for targeted and efficient anti-cancer therapy by selective targeting and cancer cell death via apoptosis and mitotic cell cycle arrest.

Magnetic nanoparticles applied in targeted therapy and magnetic resonance imaging: crucial preparation parameters, indispensable pre-treatments, updated research advancements and future perspectives

Magnetic nanoparticles (MNPs) have attracted much attention in cancer treatment as carriers for drug delivery and imaging contrast agents due to their distinctive performances based on their magnetic properties and nanoscale structure. In this review, we aim to comprehensively dissect how the applications of MNPs in targeted therapy and magnetic resonance imaging are achieved and their specificities by focusing on the following aspects: (1) several important preparation parameters (pH, temperature, ratio of the reactive substances, etc.) that have crucial effects on the properties of MNPs, (2) indispensable treatments to improve the biocompatibility, stability, and targeting ability of MNPs and prolong their circulation time for biomedical applications, (3) the mechanism for MNPs to deliver and release medicine to the desired sites and be applied in magnetic hyperthermia as well as related updated research advancements, (4) comparatively promising research directions of MNPs in magnetic resonance imaging, and (5) perspectives in the further optimization of their preparations, pre-treatments and applications in cancer diagnosis and therapy.

PolyRad - Protection Against Free Radical Damage

The effects of elevated levels of radiation contribute to the instability of pharmaceutical formulations in space compared to those on earth. Existing technologies are ineffective at maintaining the therapeutic efficacies of drugs in space. Thus, there is an urgent need to develop novel space-hardy formulations for preserving the stability and efficacy of drug formulations. This work aims to develop a novel approach for the protection of space pharmaceutical drug molecules from the radiation-induced damage to help extend or at least preserve their structural integrity and potency. To achieve this, free radical scavenging antioxidant, Trolox was conjugated on the surface of poly-lactic-co-glycolic acid (PLGA) nanoparticles for the protection of a candidate drug, melatonin that is used as a sleep aid medication in International Space Station (ISS). Melatonin-PLGA-PLL-Trolox nanoparticle as named as PolyRad was synthesized employing single oil in water (o/w) emulsion solvent evaporation method. PolyRad is spherical in shape and has an average diameter of ~600 nm with a low polydispersity index of 0.2. PolyRad and free melatonin (control) were irradiated by UV light after being exposed to a strong oxidant, hydrogen peroxide (H₂O₂). Bare melatonin lost ~80% of the active structure of the drug following irradiation with UV light or treatment with H₂O₂. In contrast, PolyRad protected >80% of the active structure of melatonin. The ability of PolyRad to protect melatonin structure was also carried out using 0, 1, 5 and 10 Gy gamma radiation. Gamma irradiation showed >98% active structures of melatonin encapsulated in PolyRads. Drug release and effectiveness of melatonin using PolyRad were evaluated on human umbilical vein endothelial cells (HUVEC) in vitro. Non-irradiated PolyRad demonstrated maximum drug release of ~70% after 72 h, while UV-irradiated and H₂O₂-treated PolyRad showed a maximum drug release of ~85%. Cytotoxicity of melatonin was carried out using both live/dead and MTT assays. Melatonin, non-radiated PolyRad and irradiated PolyRad inhibited the viability of HUVEC in a dose-dependent manner. Cell viability of melatonin, PolyRad alone without melatonin (PolyRad carrier control), non-radiated PolyRad, and irradiated PolyRad were ~98, 87, 75 and 70%, respectively at a concentration \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \sim $$\end{document}~ 0.01 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${mg}/{ml}$$\end{document}mg/ml (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$10\mu g/{ml}$$\end{document}10μg/ml). Taken together, PolyRad nanoparticle provides an attractive formulation platform for preventing damage to pharmaceutical drugs in potential space mission applications.

Nonspherical chiral helical polymer particles with programmable morphology prepared by electrospraying

Chirality and chiral materials demonstrate ever-growing importance. As a new type of chiral material, chiral polymer particles hold huge potential in both scientific research and practical applications. Meanwhile, nonspherical polymer particles (NPPs) have witnessed substantial progress in recent years because of their unique structures and especially the properties distinguishable from the corresponding spherical particles. We hypothesize that combining chirality with NPPs will open up an unprecedented category of advanced materials. The present contribution reports the first protocol for preparing electrosprayed nonspherical chiral particles constructed from chiral helical polymers, using helical substituted polyacetylenes as the model. SEM images demonstrate the successful fabrication of nonspherical chiral particles with tunable morphologies (bowl-, golf- and apple-like particles). Circular dichroism (CD) measurement proves the remarkable optical activity of the particles, which is observed in the predominantly one-handed helical polymer chains. The present work establishes a novel, versatile, and powerful platform for preparing nonspherical chiral polymer particles with controllable morphology.

Polymer coated gold-ferric oxide superparamagnetic nanoparticles for theranostic applications

BACKGROUND

Engineered inorganic nanoparticles (NPs) are essential components in the development of nanotechnologies. For applications in nanomedicine, particles need to be functionalized to ensure a good dispersibility in biological fluids. In many cases however, functionalization is not sufficient: the particles become either coated by a corona of serum proteins or precipitate out of the solvent. We show that by changing the coating of magnetic iron oxide NPs using poly-L-lysine (PLL) polymer the colloidal stability of the dispersion is improved in aqueous solutions including water, phosphate buffered saline (PBS), PBS with 10% fetal bovine serum (FBS) and cell culture medium, and the internalization of the NPs toward living mammalian cells is profoundly affected.

METHODS

A multifunctional magnetic NP is designed to perform a near-infrared (NIR)-responsive remote control photothermal ablation for the treatment of breast cancer. In contrast to the previously reported studies of gold (Au) magnetic (Fe3O4) core-shell NPs, a Janus-like nanostructure is synthesized with Fe3O4 NPs decorated with Au resulting in an approximate size of 60 nm mean diameter. The surface of trisoctahedral Au-Fe3O4 NPs was coated with a positively charged polymer, PLL to deliver the NPs inside cells. The PLL-Au-Fe3O4 NPs were characterized by transmission electron microscopy (TEM), XRD, FT-IR and dynamic light scattering (DLS). The unique properties of both Au surface plasmon resonance and superparamagnetic moment result in a multimodal platform for use as a nanothermal ablator and also as a magnetic resonance imaging (MRI) contrast agent, respectively. Taking advantage of the photothermal therapy, PLL-Au-Fe3O4 NPs were incubated with BT-474 and MDA-MB-231 breast cancer cells, investigated for the cytotoxicity and intracellular uptake, and remotely triggered by a NIR laser of ~ 808 nm (1 W/cm2 for 10 min).

RESULTS

The PLL coating increased the colloidal stability and robustness of Au-Fe3O4 NPs (PLL-Au-Fe3O4) in biological media including cell culture medium, PBS and PBS with 10% fetal bovine serum. It is revealed that no significant (< 10%) cytotoxicity was induced by PLL-Au-Fe3O4 NPs itself in BT-474 and MDA-MB-231 cells at concentrations up to 100 μg/ml. Brightfield microscopy, fluorescence microscopy and TEM showed significant uptake of PLL-Au-Fe3O4 NPs by BT-474 and MDA-MB-231 cells. The cells exhibited 40 and 60% inhibition in BT-474 and MDA-MB-231 cell growth, respectively following the internalized NPs were triggered by a photothermal laser using 100 μg/ml PLL-Au-Fe3O4 NPs. The control cells treated with NPs but without laser showed < 10% cell death compared to no laser treatment control CONCLUSION: Combined together, the results demonstrate a new polymer gold superparamagnetic nanostructure that integrates both diagnostics function and photothermal ablation of tumors into a single multimodal nanoplatform exhibiting a significant cancer cell death.

Correction in Bicinchoninic Acid (BCA) Absorbance Assay to Analyze Protein Concentration

Conducting the bicinchoninic acid (BCA) assay directly after a coupling reaction using (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide) (EDC) and [Formula: see text]-hydroxysuccinimide (NHS) chemistry produces significant errors. Here we present a correction for the quantification of gelatin in the supernatant (SN) following gelatin conjugation to polymer microparticles using EDC and NHS chemistry. Following the conjugation reaction, SNs from the gelatin-microparticle formation reaction are treated with BCA assay reagents and quantified for the percentage of unbound gelatin in the solution. NHS was found to interfere with the BCA assay reagents and is dependent on incubation time. It is found that the large concentration (500[Formula: see text][Formula: see text]g/mL) of NHS in the conjugation reaction interferes with the sensitivity of gelatin present in SNs. The interference from NHS requires a careful analysis to distinguish the BCA background absorbance from the sample absorbance. Using an NHS control solution can correct NHS interference and thus decrease the expensive iterations in gelatin quantification and enable accurate analysis of gelatin content. The accuracy of gelatin quantification is further improved by reducing the BCA assay incubation time to approximately 20[Formula: see text]min, compared with the recommended 30[Formula: see text]min. This re-assessment of BCA assay is important to avoid misestimating biases in bioconjugation processes.

Current status and future developments in preparation and application of nonspherical polymer particles

Nonspherical polymer particles (NPPs) are nano/micro-particulates of macromolecules that are anisotropic in shape, and can be designed anisotropic in chemistry. Due to shape and surface anisotropies, NPPs bear many unique structures and fascinating properties which are distinctly different from those of spherical polymer particles (SPPs). In recent years, the research on NPPs has surprisingly blossomed in recent years, and many practical materials based on NPPs with potential applications in photonic device, material science and biomedical engineering have been generated. In this review, we give a systematic, balanced and comprehensive summary of the main aspects of NPPs related to their preparation and application, and propose perspectives for the future developments of NPPs.

PCL and PCL-based materials in biomedical applications

Biodegradable polymers have met with an increasing demand in medical usage over the last decades. One of such polymers is poly(ε-caprolactone) (PCL), which is a polyester that has been widely used in tissue engineering field for its availability, relatively inexpensive price and suitability for modification. Its chemical and biological properties, physicochemical state, degradability and mechanical strength can be adjusted, and therefore, it can be used under harsh mechanical, physical and chemical conditions without significant loss of its properties. Degradation time of PCL is quite long, thus it is used mainly in the replacement of hard tissues in the body where healing also takes an extended period of time. It is also used at load-bearing tissues of the body by enhancing its stiffness. However, due to its tailorability, use of PCL is not restricted to one type of tissue and it can be extended to engineering of soft tissues by decreasing its molecular weight and degradation time. This review outlines the basic properties of PCL, its composites, blends and copolymers. We report on various techniques for the production of different forms, and provide examples of medical applications such as tissue engineering and drug delivery systems covering the studies performed in the last decades.

Heteromer Nanostars by Spontaneous Self-Assembly

Heteromer star-shaped nanoparticles have the potential to carry out therapeutic agents, improve intracellular uptake, and safely release drugs after prolonged periods of residence at the diseased site. A one-step seed mediation process was employed using polylactide-co-glycolic acid (PLGA), polyvinyl alcohol (PVA), silver nitrate, and tetrakis(hydroxymethyl)phosphonium chloride (THPC). Mixing these reagents followed by UV irradiation successfully produced heteromer nanostars containing a number of arm chains attached to a single core with a high yield. The release of THPC from heteromer nanostars was tested for its potential use for breast cancer treatment. The nanostars present a unique geometrical design exhibiting a significant intracellular uptake by breast cancer cells but low cytotoxicity that potentiates its efficacy as drug carriers.

Therapeutic implications of tumor interstitial acidification

Interstitial acidification is a hallmark of solid tumor tissues resulting from the combination of different factors, including cellular buffering systems, defective tissue perfusion and high rates of cellular metabolism. Besides contributing to tumor pathogenesis and promoting tumor progression, tumor acidosis constitutes an important intrinsic and extrinsic mechanism modulating therapy sensitivity and drug resistance. In fact, pharmacological properties of anticancer drugs can be affected not only by tissue structure and organization but also by the distribution of the interstitial tumor pH. The acidic tumor environment is believed to create a chemical barrier that limits the effects and activity of many anticancer drugs. In this review article we will discuss the general protumorigenic effects of acidosis, the role of tumor acidosis in the modulation of therapeutic efficacy and potential strategies to overcome pH-dependent therapy-resistance.