Well-defined gold nanoparticles (AuNPs) are accessible via simple synthetic methods, and their surface chemistry stands as a key factor in determining applications in the biomedical field. While macromolecules featuring amino groups are already known to successfully mediate the formation of stable gold colloids in one-pot, two-reactant, no workup reactions in aqueous media, we herein report the discovery that, under mild reaction temperatures, polymers of outstanding biomedical interest not only can play the simultaneous role of reducing and capping agent but also lead to particulate systems with unique features. From a library of samples that included branched polyethylenimine (BPEI), poly-(l-lysine) (PLL), bovine serum albumin (BSA), poly-(2-methyl-2-oxazoline) (PMeOx), poly-(N-(2-hydroxypropyl) methacrylamide) (PHPMA), and amine-functionalized poly-(N-(2-hydroxypropyl)-methacrylamide-co-N-(3-aminopropyl)-methacrylamide) P-(HPMA-co-APMA), we found that PHPMA end-functionalized with nitrile motifs generate spherical and stable AuNPs@PHPMA of very small size (diameter of ∼2.4 nm), as underlined by imaging experiments. Cell viability experiments indicated exceptionally good biocompatibility up to very high numerical particle concentrations as compared to the other systems. The reduced size imparted to the AuNPs@PHPMA outstanding catalytic properties (no induction time and high reaction rate constant for the hydrogenation of p-nitrophenol) and antimicrobial activity (total antibacterial activity against Escherichia coli and dose-dependent antibacterial activity against Staphylococcus aureus). The introduction of primary amine groups (13.4 mol %) of higher nucleophilicity known to work better for AuNP synthesis makes these unique features disappear, as evidenced for P-(HPMA-co-APMA). The other systems yielded 6-28 nm particles whose properties reflected both the size of the metallic core and chemical nature and conformation of the capping agent. These findings point to novel applications of PHPMA polymers worthy of further development, especially in light of their excellent water solubility and biocompatibility.

• Publication type
• Journal Article MeSH

Biodegradable nanomedicines are widely studied as candidates for the effective treatment of various cancerous diseases. Here, we present the design, synthesis and evaluation of biodegradable polymer-based nanomedicines tailored for tumor-associated stimuli-sensitive drug release and polymer system degradation. Diblock polymer systems were developed, which enabled the release of the carrier drug, pirarubicin, via a pH-sensitive spacer allowing for the restoration of the drug cytotoxicity solely in the tumor tissue. Moreover, the tailored design enables the matrix-metalloproteinases- or reduction-driven degradation of the polymer system into the polymer chains excretable from the body by glomerular filtration. Diblock nanomedicines take advantage of an enhanced EPR effect during the initial phase of nanomedicine pharmacokinetics and should be easily removed from the body after tumor microenvironment-associated biodegradation after fulfilling their role as a drug carrier. In parallel with the similar release profiles of diblock nanomedicine to linear polymer conjugates, these diblock polymer conjugates showed a comparable in vitro cytotoxicity, intracellular uptake, and intratumor penetration properties. More importantly, the diblock nanomedicines showed a remarkable in vivo anti-tumor efficacy, which was far more superior than conventional linear polymer conjugates. These findings suggested the advanced potential of diblock polymer conjugates for anticancer polymer therapeutics.

• Keywords
• HPMA conjugate, anticancer, diblock conjugate, drug delivery, pirarubicin,
• Publication type
• Journal Article MeSH

Design, controlled synthesis, physico-chemical and biological characteristics of novel well-defined biodegradable star-shaped copolymers intended for advanced drug delivery is described. These new biocompatible star copolymers were synthesised by grafting monodispersed semitelechelic linear (sL) N-(2-hydroxypropyl)methacrylamide copolymers onto a 2,2-bis(hydroxymethyl)propionic acid (bisMPA)-based polyester dendritic core of various structures. The hydrodynamic diameter of the star copolymer biomaterials can be tuned from 13 to 31 nm and could be adjusted to a given purpose by proper selection of the bisMPA dendritic core type and generation and by considering the sL copolymer molecular weight and polymer-to-core molar ratio. The hydrolytic degradation was proved for both the star copolymers containing either dendron or dendrimer core, showing the spontaneous hydrolysis in duration of few weeks. Finally, it was shown that the therapy with the biodegradable star conjugate with attached doxorubicin strongly suppresses the tumour growth in mice and is fully curative in most of the treated animals at dose corresponding approximately to one fourth of maximum tolerated dose (MTD) value. Both new biodegradable systems show superior efficacy and tumour accumulation over the first generation of star copolymers containing non-degradable PAMAM core.

• Keywords
• Cancer, Doxorubicin, Drug delivery, HPMA, Star-like polymers, bisMPA,
• MeSH
• Acrylamides MeSH
• Biocompatible Materials * MeSH
• Doxorubicin MeSH
• Pharmaceutical Preparations * MeSH
• Drug Delivery Systems MeSH
• Methacrylates MeSH
• Mice MeSH
• Cell Line, Tumor MeSH
• Drug Carriers MeSH
• Polymers MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• Acrylamides MeSH
• Biocompatible Materials * MeSH
• Doxorubicin MeSH
• hydroxypropyl methacrylate MeSH Browser
• Pharmaceutical Preparations * MeSH
• Methacrylates MeSH
• N-(2-hydroxypropyl)methacrylamide MeSH Browser
• Drug Carriers MeSH
• Polymers MeSH

Rationale: The blood-brain barrier (BBB) is a major obstacle for drug delivery to the brain. Sonopermeation, which relies on the combination of ultrasound and microbubbles, has emerged as a powerful tool to permeate the BBB, enabling the extravasation of drugs and drug delivery systems (DDS) to and into the central nervous system (CNS). When aiming to improve the treatment of high medical need brain disorders, it is important to systematically study nanomedicine translocation across the sonopermeated BBB. To this end, we here employed multimodal and multiscale optical imaging to investigate the impact of DDS size on brain accumulation, extravasation and penetration upon sonopermeation. Methods: Two prototypic DDS, i.e. 10 nm-sized pHPMA polymers and 100 nm-sized PEGylated liposomes, were labeled with fluorophores and intravenously injected in healthy CD-1 nude mice. Upon sonopermeation, computed tomography-fluorescence molecular tomography, fluorescence reflectance imaging, fluorescence microscopy, confocal microscopy and stimulated emission depletion nanoscopy were used to study the effect of DDS size on their translocation across the BBB. Results: Sonopermeation treatment enabled safe and efficient opening of the BBB, which was confirmed by staining extravasated endogenous IgG. No micro-hemorrhages, edema and necrosis were detected in H&E stainings. Multimodal and multiscale optical imaging showed that sonopermeation promoted the accumulation of nanocarriers in mouse brains, and that 10 nm-sized polymeric DDS accumulated more strongly and penetrated deeper into the brain than 100 nm-sized liposomes. Conclusions: BBB opening via sonopermeation enables safe and efficient delivery of nanomedicine formulations to and into the brain. When looking at accumulation and penetration (and when neglecting issues such as drug loading capacity and therapeutic efficacy) smaller-sized DDS are found to be more suitable for drug delivery across the BBB than larger-sized DDS. These findings are valuable for better understanding and further developing nanomedicine-based strategies for the treatment of CNS disorders.

• Keywords
• Blood-brain barrier, Drug delivery, Microbubbles, Nanomedicine, Ultrasound,
• MeSH
• Fluorescent Dyes administration & dosage   MeSH
• Blood-Brain Barrier diagnostic imaging   metabolism   MeSH
• Drug Delivery Systems methods   MeSH
• Liposomes administration & dosage   MeSH
• Microbubbles MeSH
• Brain diagnostic imaging   MeSH
• Mice, Nude MeSH
• Mice MeSH
• Nanomedicine methods   MeSH
• Brain Diseases drug therapy   MeSH
• Optical Imaging methods   MeSH
• Ultrasonography methods   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Fluorescent Dyes MeSH
• Liposomes MeSH

Here we describe the synthesis and biological properties of two types of star-shaped polymer-doxorubicin conjugates: non-targeted conjugate prepared as long-circulating high-molecular-weight (HMW) polymer prodrugs with a dendrimer core and a targeted conjugate with the anti-CD20 monoclonal antibody (mAb) rituximab (RTX). The copolymers were linked to the dendrimer core or to the reduced mAb via one-point attachment forming a star-shaped structure with a central antibody or dendrimer surrounded by hydrophilic polymer chains. The anticancer drug doxorubicin (DOX) was attached to the N-(2-hydroxypropyl)methacrylamide (HPMA)-based copolymer chain in star polymer systems via a pH-labile hydrazone linkage. Such polymer-DOX conjugates were fairly stable in aqueous solutions at pH 7.4, and the drug was readily released in mildly acidic environments at pH 5-5.5 by hydrolysis of the hydrazone bonds. The cytotoxicity of the polymer conjugates was tested on several CD20-positive or negative human cell lines. Similar levels of in vitro cytotoxicity were observed for all tested polymer conjugates regardless of type or structure. In vivo experiments using primary cell-based murine xenograft models of human diffuse large B-cell lymphoma confirmed the superior anti-lymphoma efficacy of the polymer-bound DOX conjugate when compared with the original drug. Targeting with RTX did not further enhance the anti-lymphoma efficacy relative to the non-targeted star polymer conjugate. Two mechanisms could play roles in these findings: changes in the binding ability to the CD-20 receptor and a significant loss of the immunological properties of RTX in the polymer conjugates.

• Keywords
• HPMA copolymers, doxorubicin, drug delivery systems, drug targeting, monoclonal antibody,
• MeSH
• Apoptosis drug effects   MeSH
• Doxorubicin chemistry   pharmacology   MeSH
• Drug Delivery Systems MeSH
• Humans MeSH
• Lymphoma drug therapy   mortality   pathology   MeSH
• Disease Models, Animal MeSH
• Mice MeSH
• Cell Line, Tumor MeSH
• Polymers * chemistry   MeSH
• Prodrugs * chemistry   pharmacology   MeSH
• Antineoplastic Agents chemistry   pharmacology   MeSH
• Rituximab chemistry   pharmacology   MeSH
• Drug Liberation MeSH
• Cell Survival drug effects   MeSH
• Xenograft Model Antitumor Assays MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Doxorubicin MeSH
• Polymers * MeSH
• Prodrugs * MeSH
• Antineoplastic Agents MeSH
• Rituximab MeSH

The synthesis of a series of novel, water-soluble poly(organophosphazenes) prepared via living cationic polymerization is presented. The degradation profiles of the polyphosphazenes prepared are analyzed by GPC, 31P NMR spectroscopy, and UV-Vis spectroscopy in aqueous media and show tunable degradation rates ranging from days to months, adjusted by subtle changes to the chemical structure of the polyphosphazene. Furthermore, it is observed that these polymers demonstrate a pH-promoted hydrolytic degradation behavior, with a remarkably faster rate of degradation at lower pH values. These degradable, water soluble polymers with controlled molecular weights and structures could be of significant interest for use in aqueous biomedical applications, such as polymer therapeutics, in which biological clearance is a requirement and in this context cell viability tests are described which show the non-toxic nature of the polymers as well as their degradation intermediates and products.

• Keywords
• biocompatible polymers, biodegradable polymers, polymer therapeutics, polyphosphazenes, water-soluble polymers,
• Publication type
• Journal Article MeSH

To avoid the side effects of the anti-cancer drug doxorubicin (Dox), we conjugated this drug to a N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer backbone. Dox was conjugated via an amide bond (Dox-HPMA(AM), PK1) or a hydrazone pH-sensitive bond (Dox-HPMA(HYD)). In contrast to Dox and Dox-HPMA(HYD), Dox-HPMA(AM) accumulates within the cell's intracellular membranes, including those of the Golgi complex and endoplasmic reticulum, both involved in protein glycosylation. Flow cytometry was used to determine lectin binding and cell death, immunoblot to characterize the presence of CD7, CD43, CD44, and CD45, and high-performance anion exchange chromatography with pulsed amperometric detector analysis for characterization of plasma membrane saccharide composition. Incubation of EL4 cells with Dox-HPMA(AM) conjugate, in contrast to Dox or Dox-HPMA(HYD), increased the amounts of membrane surface-associated glycoproteins, as well as saccharide moieties recognized by peanut agglutinin, Erythrina cristagalli, or galectin-1 lectins. Only Dox-HPMA(AM) increased expression of the highly glycosylated membrane glycoprotein CD43, while expression of others (CD7, CD44, and CD45) was unaffected. The binding sites for galectin-1 are present on CD43 molecule. Furthermore, we present that EL4 treated with Dox-HPMA(AM) possesses increased sensitivity to galectin-1-induced apoptosis. In this study, we demonstrate that Dox-HPMA(AM) treatment changes glycosylation of the EL4 T cell lymphoma surface and sensitizes the cells to galectin-1-induced apoptosis.

• MeSH
• Amides chemistry   MeSH
• Leukosialin metabolism   MeSH
• Apoptosis MeSH
• Doxorubicin analogs & derivatives   pharmacology   MeSH
• Endoplasmic Reticulum metabolism   MeSH
• Galectin 1 metabolism   MeSH
• Glycosylation MeSH
• Golgi Apparatus metabolism   MeSH
• Polymethacrylic Acids pharmacology   MeSH
• Lymphoma, T-Cell drug therapy   metabolism   pathology   MeSH
• Mice MeSH
• Cell Line, Tumor drug effects   MeSH
• Drug Carriers MeSH
• Cell Proliferation MeSH
• Antibiotics, Antineoplastic pharmacology   MeSH
• Flow Cytometry MeSH
• Blotting, Western MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Amides MeSH
• Leukosialin MeSH
• doxorubicin-N-(2-hydroxypropyl)methacrylamide copolymer conjugate MeSH Browser
• Doxorubicin MeSH
• Galectin 1 MeSH
• Polymethacrylic Acids MeSH
• Drug Carriers MeSH
• Antibiotics, Antineoplastic MeSH

PURPOSE: In vivo efficacy and safety of HPMA-based copolymers armed with doxorubicin via a spacer containing pH-sensitive linkage that can be prepared within a broad range of attached drug contents (1) was tested in murine tumor models. METHODS: Mice bearing T cell lymphoma EL4 or B cell lymphoma 38C13 were treated with a single dose of the conjugate (15, 25, and 75 mg Dox eq./kg i.v.) in a therapeutic regime. Anti-tumor resistance of the cured animals was proved by a second challenge with a lethal dose of tumor cells without additional treatment. RESULTS: The content of drug bound to the polymer is an important parameter in relation to the conjugate therapeutic efficacy. The best anti-tumor effects were produced by conjugates with 10 - 13 wt% of bound doxorubicin. Free doxorubicin up to 4.6% relative to total drug content had no impact on the treatment efficacy and acute toxicity. The conjugates induced a complete cure of mice and regular treatment-dependent development of specific anti-tumor resistance. No myelosuppression or organ damage was observed. CONCLUSIONS: A well-defined HPMA copolymer-doxorubicin conjugate with pH-sensitive drug release is a good candidate for clinical trials as it has remarkable anti-tumor efficacy and a favorable safety profile.

• MeSH
• Doxorubicin analogs & derivatives   chemical synthesis   pharmacokinetics   pharmacology   MeSH
• Immunomodulation drug effects   MeSH
• Hydrogen-Ion Concentration MeSH
• Polymethacrylic Acids chemical synthesis   pharmacokinetics   pharmacology   MeSH
• Mice MeSH
• Cell Line, Tumor MeSH
• Drug Carriers chemical synthesis   pharmacokinetics   pharmacology   MeSH
• Polymers * chemical synthesis   pharmacokinetics   pharmacology   MeSH
• Cell Proliferation drug effects   MeSH
• Antibiotics, Antineoplastic pharmacokinetics   pharmacology   MeSH
• Xenograft Model Antitumor Assays MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• doxorubicin-N-(2-hydroxypropyl)methacrylamide copolymer conjugate MeSH Browser
• Doxorubicin MeSH
• Polymethacrylic Acids MeSH
• Drug Carriers MeSH
• Polymers * MeSH
• Antibiotics, Antineoplastic MeSH