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Conventional synthesis methods of polymeric nanoparticles as drug delivery systems are based on the use of large amounts of organic solvents, hence requiring several steps for the obtaining of waterborne dispersions. In view of the need for new environmentally friendly methods, emulsion polymerization and their related techniques are a good alternative for the production of monodispersed waterborne dispersions of biodegradable nanoparticles in a cleaner, reproducible and faster manner.Herein, the miniemulsion polymerization technique at low temperature using poly(2-ethyl-2-oxazoline) as surfactant has been developed for poly(hydroxyethyl methacrylate-lactic acid) and poly(hydroxyethyl methacrylate-lactic-co-glycolic acid) nanoparticles. Additionally, the anti-inflammatory drug BRP-187 was used to proof the potential of this technique in the encapsulation of hydrophobic drugs. The effect of the oligomer composition on the miniemulsion and the final dispersion stability, the final oligomer conversion, the polymer particle size and the drug encapsulation efficiency has been studied.Monodisperse spherical particles ranging between 170 and 250 nm in diameter in long term non-toxic stable waterborne dispersions were obtained with drug encapsulation efficiencies up to 66%. In contrast with conventional synthesis techniques, residual organic solvents are completely removed and, thus, the potential of redox initiated miniemulsion polymerization to obtain stable drug loaded poly(hydroxyethyl methacrylate-lactic acid) and poly(hydroxyethyl methacrylate-lactic-co-glycolic acid) nanoparticles in an efficient and fast manner is shown.

Within this study, an amphiphilic and potentially biodegradable polypeptide library based on poly[(4-aminobutyl)-l-glutamine

A 60-membered library of vitamin A-functionalized P(MMA-stat-DMAEMA)-b-PPEGMA block copolymers was synthesized by RAFT polymerization. The retinoic acid was coupled to hydroxyl groups present in the hydrophilic PPEGMA block. The polymers were investigated for their ability to encapsulate ribonucleic acids through nanoparticle (NP) formulation using the emulsion/solvent evaporation method. The localization of retinyl in surface-near regions of the NPs was indicated by surface enhanced Raman spectroscopy, and the interaction of the NPs with a retinol binding protein was investigated by an analytical ultracentrifuge. The systematic analysis of the NP library in terms of the encapsulation efficiency of the ribonucleic acids, the toxicity of the NPs, and the cellular uptake helped identifying suitable candidates for cellular internalization studies. The cell uptake was investigated by flow cytometry and fluorescence microscopy and reveals structure dependent uptake behavior of the examined particles.

Smart nano-carriers such as micelles, vesicles or nanoparticles constructed from amphiphilic polymers promise a new generation of drug delivery systems featuring localized and controlled release. Keeping the considerable effort for the synthesis of these polymers in mind, supramolecular host–guest interactions represent an interesting alternative to engineer amphiphilic materials with multiple functionalities. Using the known interaction of pillar[5]arenes with aromatic guests such as viologen-derivatives, we designed quasi-block copolymers based on polycaprolactone (PCL) and either the neutral and biocompatible poly(N-acryloyl morpholine) (PNAM-P[5]) or the structurally similar but pH-responsive poly(N-acryloyl-N′-methyl piperazine) (PNAMP-P[5]), which were modified with the pillar[5]arene. Self-assembly experiments in water resulted in the formation of small spherical nanostructures for the methyl viologen-polycaprolactone (viologen-PCL), but surprisingly also for the non-functionalized PCL. However, only the pH-responsive PNAMP-P[5] provided stable structures in the buffer for both cases, while PNAM-P[5] resulted in aggregation. Additional degradation studies revealed that the presence of host–guest complexes could retard the disintegration of the particles at low pH (5.1) in comparison to the particles based on plain PCL, while all structures remained stable at neutral pH value. In combination with their excellent biocompatibility, the presented supramolecular approach to stabilize PCL nanoparticles with pH-responsive polymers pave a convenient way to degradable delivery systems with tailored release profiles.

Nanogels have become one of the most attractive systems for application as delivery vectors or for theragnostic approaches in nanomedicine, which is mainly related to the ease of their synthesis by precipitation polymerization. However, only a few suitable monomers have been reported so far and stabilization of the nanogels requires the incorporation of rather defined amounts of in most cases charged co-monomers, such as acrylic acid, which limits the flexibility in their design. Here, we present an alternative approach using a pyridinium based monomer, which not only provides stability due to the positive charge, but also allows the attachment of functional carboxylate-pillar[5]arene by the formation of a host-guest complex. This approach is tested on pH-sensitive nanogels based on the monomer N-[(2,2-dimethyl-1,3-dioxolane)methyl]acrylamide (DMDOMA) featuring an acetal group, which is hydrolysed under acidic conditions. As carboxylates are known to catalyze this hydrolysis, we tested different amounts of carboxylate-pillar[5]arenes to tune the hydrolysis rate of the acetal group and found a direct correlation. Additional encapsulation studies with doxorubicin (DOX) revealed that surface potential and charge density represent additional key factors not only for the loading capacity, but also for the release profile of the nanogels. The option to tune such properties simply by the addition of a co-factor, in this case, the carboxylate-pillar[5]arenes provides a powerful tool to optimize characteristics of functional nanogels for drug delivery or other applications.

NGS-based multiple gene panel resequencing in combination with a high resolution CGH-array was used to identify genetic risk factors for hereditary breast and/or ovarian cancer in 237 high risk patients who were previously tested negative for pathogenic BRCA1/2 variants. All patients were screened for pathogenic variants in 94 different cancer predisposing genes. We identified 32 pathogenic variants in 14 different genes (ATM, BLM, BRCA1, CDH1, CHEK2, FANCG, FANCM, FH, HRAS, PALB2, PMS2, PTEN, RAD51C and NBN) in 30 patients (12.7%). Two pathogenic BRCA1 variants that were previously undetected due to less comprehensive and sensitive methods were found. Five pathogenic variants are novel, three of which occur in genes yet unrelated to hereditary breast and/or ovarian cancer (FANCG, FH and HRAS). In our cohort we discovered a remarkably high frequency of truncating variants in FANCM (2.1%), which has recently been suggested as a susceptibility gene for hereditary breast cancer. Two patients of our cohort carried two different pathogenic variants each and 10 other patients in whom a pathogenic variant was confirmed also harbored a variant of unknown significance in a breast and ovarian cancer susceptibility gene. We were able to identify pathogenic variants predisposing for tumor formation in 12.3% of BRCA1/2 negative breast and/or ovarian cancer patients.

The administration of drugs, as a main challenge of pharmaceutical and medicinal applications, has certainly benefited from the application of synthetic polymers. However, despite an enormous effort to develop new materials for drug delivery applications, only few of them have entered the market due to the hurdles of regulation, production, cost efficiency and both industrial’s and patients’ acceptance. In this review, we summarize all these classes of synthetic polymers, which are on the market as well as the latest developments in clinical trials, and describe their application in polymer-drug conjugates, as excipients, in nano-/microscopic and macroscopic drug carriers, as polymeric coatings, or as polymeric drugs. Our intention is to create a link between the underlying chemical structures, the properties of the polymers, and their area of application, where they are often just known by their trade names or abbreviations. In addition selected types of synthetic polymers are highlighted that feature interesting properties and have the potential to make it to the market in future.

In the present work, the polymerization process of ethylene oxide (EO) leading to diphenyl-PEO-OH with a molar mass of 5000 and 10,000 g mol−1 in different ethers used as solvents was investigated. The aim was to gain access to the kinetics of the anionic ring-opening polymerization (AROP) of EO by an online and in-situ real-time method and to test alternative “greener” solvents in comparison to the well-established solvents, e.g. tetrahydrofuran (THF). For this purpose, we chose two promising “green” ethers, methyl tetrahydrofuran (MeTHF) and cyclopentyl methyl ether (CPME), with improved properties regarding reduced peroxide formation, higher boiling points, easier drying, and lower water solubility. During the AROP in the custom-built setup, in-situ IR measurements were performed and the final products were characterized by SEC, MALDI-TOF-MS, and 1H NMR measurements, as well as newly in-house developed liquid chromatography (LC) investigations for purity analysis and diol impurity content estimations. Results presented in this study show that the controlled polymerization of EO in the tested alternative solvents represents a viable alternative to commonly established ones, as based on our kinetic studies and product characterization results.

A benzoin-derived diol linker was synthesized and used to generate biocompatible polyesters that can be fully decomposed on demand upon UV irradiation. Extensive structural optimization of the linker unit was performed to enable the defined encapsulation of diverse organic compounds in the polymeric structures and allow for a well-controllable polymer cleavage process. Selective tracking of the release kinetics of encapsulated model compounds from the polymeric nano- and microparticle containers was performed by confocal laser scanning microscopy in a proof-of-principle study. The physicochemical properties of the incorporated and released model compounds ranged from fully hydrophilic to fully hydrophobic. The demonstrated biocompatibility of the utilized polyesters and degradation products enables their use in advanced applications, for example, for the smart packaging of UV-sensitive pharmaceuticals, nutritional components, or even in the area of spatially selective self-healing processes.

We synthesized a novel thermoresponsive and pH-degradable polymer, (poly(N-[(2,2-dimethyl-1,3-dioxolane)methyl]acrylamide)), with a pyridinium salt based end group, which can form a host–guest complex with various pillar[5] arenes. This complex formation led to an increase of the LCST of the polymer whereat carboxylate functionalized pillar[5] arenes caused a stronger shift than the respective oligoethylene oxide modified ones. This trend is found to be coherent with the strength of interaction of the respective host and guest, which was analyzed by NMR studies and isothermal titration calorimetry (ITC). Further investigations on this complex revealed that the hydrolysis of the polymer can be accelerated in the presence of the carboxylate based pillar arene under acidic conditions, which was not the case for the oligoethylene oxide modified system or a structurally similar carboxylic acid unit not forming a complex. The host–guest interaction therefore not only represents a versatile approach to tune the solubility behavior of polymers, but also influences pH dependent degradability.

Congenital anomalies of the kidneys and urinary tract (CAKUT) are the most common cause of chronic kidney disease in children. As CAKUT is a genetically heterogeneous disorder and most cases are genetically unexplained, we aimed to identify new CAKUT causing genes. Using whole-exome sequencing and trio-based de novo analysis, we identified a novel heterozygous de novo frameshift variant in the leukemia inhibitory factor receptor (LIFR) gene causing instability of the mRNA in a patient presenting with bilateral CAKUT and requiring kidney transplantation at one year of age. LIFR encodes a transmembrane receptor utilized by IL-6 family cytokines, mainly by the leukemia inhibitory factor (LIF). Mutational analysis of 121 further patients with severe CAKUT yielded two rare heterozygous LIFR missense variants predicted to be pathogenic in three unrelated patients. LIFR mutants showed decreased half-life and cell membrane localization resulting in reduced LIF-stimulated STAT3 phosphorylation. LIFR showed high expression in human fetal kidney and the human ureter, and was also expressed in the developing murine urogenital system. Lifr knockout mice displayed urinary tract malformations including hydronephrosis, hydroureter, ureter ectopia, and, consistently, reduced ureteral lumen and muscular hypertrophy, similar to the phenotypes observed in patients carrying LIFR variants. Additionally, a form of cryptorchidism was detected in all Lifr-/- mice and the patient carrying the LIFR frameshift mutation. Altogether, we demonstrate heterozygous novel or rare LIFR mutations in 3.3% of CAKUT patients, and provide evidence that Lifr deficiency and deactivating LIFR mutations cause highly similar anomalies of the urogenital tract in mice and humans.

The synthesis of retinol initiated polylactide (PLA) by ring opening polymerization (ROP) of L-lactide via in situ calcium alkoxide formation with all-trans-retinol and Ca[N(SiMe3)2]2(THF)2 is described. PLAs with degree of polymerization (DP) values ranging from 13 to 60 were obtained and characterized in detail by means of 1H nuclear magnetic resonance (NMR) spectroscopy, size exclusion chromatography (SEC), UV/vis spectroscopy and (tandem) mass spectrometry techniques. Stable nanoparticles (NPs) were prepared via a nanoprecipitation method and characterized by DLS and SEM. The stability of retinol upon conjugation to PLA as well as the nanoparticle formulation was investigated in detail and found to be significantly affected by the storage conditions such as exposure to light, oxygen and temperature.

A series of dual pH- and ultrasound responsive statistical copolymers were synthesized via the reversible addition–fragmentation chain transfer (RAFT) polymerization of 3,4-dihydro-2H-pyran (DHP) protected HEMA 2-((tetrahydro-2H-pyran-2-yl)oxy)ethyl methacrylate (THP-HEMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). The RAFT-controlled nature of the (co)polymerizations was verified by detailed kinetic studies. The chemical structure and the co-monomer composition of the copolymers were confirmed by 1H NMR spectroscopy. The number-average molar mass values (Mn) and dispersities (ĐM = Mw/Mn) of the copolymers were estimated by size exclusion chromatography (SEC). The thermal properties of the (co)polymers were analyzed by means of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Additionally, the DMAEMA moieties of the copolymers were quaternized with an excess of methyl iodide. The synthesized polymers self-assemble into nanoparticles in aqueous media via the nanoprecipitation method and were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Zeta potential measurements revealed that all DMAEMA containing nanoparticles undergo a surface charge conversion from positive to negative at slightly acidic pH values. However, quaternized DMAEMA nanoparticles possess pH independent positive surface charges. At acidic pH values, the nanoparticles disassemble and dissolve in water due to the protonation of the DMAEMA moieties and/or due to the acidic hydrolysis of the THP-HEMA groups. It was found that the surface charge and the stability of the nanoparticles were greatly affected by the DMAEMA content of the polymers, meaning that the isoelectric point (IEP), at which the charge is reversed and the pH value at which the disassembly occurs, increased with the higher DMAEMA content in the copolymer. Moreover, it was proven that the ionization of the carboxyl RAFT end-group of the polymers enhanced the anionic character and the stability of the nanoparticles at neutral pH values. DLS and scanning electron microscopy (SEM) measurements revealed that these nanoparticles can be further disrupted by ultrasound exposure. Nile Red was encapsulated into nanoparticles as a model hydrophobic drug. The release profile of the Nile Red was significantly accelerated in acidic media or under ultrasound exposure. The cytotoxicity assay results showed that negatively charged nanoparticles are non-toxic and biocompatible, whereas positively charged nanoparticles are extremely toxic to L929 cells.

Color selection is one of the key elements of building a strong brand development and product identity in the pharmaceutical industry, besides to prevent counterfeiting. Moreover, colored pharmaceutical dosage forms may increase patient compliance and therapy enhancement. Although most synthetic dyes are classified as safe, their regulations are stricter than other classes of excipients. Safety concerns have increased during the last years but the efforts to change to natural dyes seem to be not promising. Their instability problems and the development of "non-toxic" dyes is still a challenge. This review focuses specifically on the issues related to dye selection and summarizes the current regulatory status. A deep awareness of toxicological data based on the public domain, making sure the compliance of standards for regulation and safety for successful product development is provided. In addition, synthetic strategies are provided to covalently bind dyes on polymers to possibly overcome toxicity issues.

Achieving optimal solubility of active substances in polymeric carriers is of fundamental importance for a number of industrial applications, including targeted drug delivery within the growing field of nanomedicine. However, its experimental optimization using a trial-and-error approach is cumbersome and time-consuming. Here, an approach based on molecular dynamics (MD) simulations and the Flory-Huggins theory is proposed for rapid prediction of thermodynamic compatibility between active species and copolymers comprising hydrophilic and hydrophobic segments. In contrast to similar methods, our approach offers high computational efficiency by employing MD simulations that avoid explicit consideration of the actual copolymer chains. The accuracy of the method is demonstrated for compatibility predictions between pyrene and nile red as model dyes as well as indomethacin as model drug and copolymers containing blocks of poly(ethylene glycol) and poly(lactic acid) in different ratios. The results of the simulations are directly verified by comparison with the observed encapsulation efficiency of nanoparticles prepared by nanoprecipitation. © 2016 Wiley Periodicals, Inc.

In this study, we designed, synthesized, and characterized a novel pH- and redox responsive nanoparticle system for the enhanced spatial delivery of hydrophobic drugs. A statistical copolymer library of pyridyldisulfide ethyl methacrylate (PDSM) with different compositions of 2-((tert-butoxycarbonyl)(2-((tert-butoxycarbonyl)amino)ethyl)amino)ethyl methacrylate (BocAEAEMA) was synthesized using the reversible addition–fragmentation chain transfer (RAFT) polymerization process. The controlled nature of the radical polymerization was demonstrated by a kinetic study. The Boc-groups were cleaved to obtain the desired amino functional copolymers. Nanoparticles were prepared by nanoprecipitation and characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Differently sized nanoparticles that have monomodal size distributions ranging from 50 to 460 nm with positive ζ-potential values were obtained by varying initial conditions of the formulat...

The synthesis of novel polymeric dyes by directly attaching toluidine blue O and MPPD via EDC and CDI coupling is described for polymers with enteric properties [poly(methacrylic acid-co-ethyl acrylate)]. The polymeric dyes are analyzed by SEC and UV/Vis measurements as well as investigated regarding their dissolution and permeation characteristics. Almost no changes between the modified and nonmodified polymer could be observed by conventional drug studies and a self-established method for dissolution rates. Also no influence on the film formation properties was observed by SEM measurements. In vitro toxicity studies showed no increase of toxicity compared to the non modified polymer. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2386–2393

Contains fulltext : 153442.pdf (Publisher’s version ) (Closed access) Polymer-based gene delivery systems have enormous potential in biomedicine, but their efficiency is often limited by poor biocompatibility. Poly(methacrylate)s (PMAs) are an interesting class of polymers which allow to explore structure-activity relationships of polymer functionalities for polyplex formation in oligonucleotide delivery. Here, we synthesized and tested a library of PMA polymers, containing functional groups contributing to the different steps of gene delivery, from oligonucleotide complexation to cellular internalization and endosomal escape. By variation of the molar ratios of the individual building blocks, the physicochemical properties of the polymers and polyplexes were fine-tuned to reduce toxicity as well as to increase activity of the polyplexes. To further enhance transfection efficiency, a cell-penetrating peptide (CPP)-like functionality was introduced on the polymeric backbone. With the ability to synthesize large libraries of polymers in parallel we also developed a workflow for a mid-to-high throughput screening, focusing first on safety parameters that are accessible by high-throughput approaches such as blood compatibility and toxicity towards host cells and only at a later stage on more laborious tests for the ability to deliver oligonucleotides. To arrive at a better understanding of the molecular basis of activity, furthermore, the effect of the presence of heparan sulfates on the surface of host cells was assessed and the mechanism of cell entry and intracellular trafficking investigated for those polymers that showed a suitable pharmacological profile. Following endocytic uptake, rapid endosomal release occurred. Interestingly, the presence of heparan sulfates on the cell surface had a negative impact on the activity of those polyplexes that were sensitive to decomplexation by heparin in solution. In summary, the screening approach identified two polymers, which form polyplexes with high stability and transfection capacity exceeding the one of poly(ethylene imine) also in the presence of serum.

In 2012, the first gene therapy agent was approved by the Europe Medicines Agency leading to increased interest in this research field. Beside viruses, non-viral agents based on lipids or polymers represent aspiring alternatives to deliver the genetic material. Different hurdles have to be overcome depending on the kind of nucleic acid used, where plasmid DNA (pDNA) and small interfering RNA represent the common ones. The main challenge for transfection agents, in particular for pDNA delivery, is the transfer to the cell and into the cell nuclei. Within the group of transfection vesicles, cationic polymers show promising features and variability, as they can be synthesized with tailor-made physical and chemical properties (architectures and functionalisation). In the field of polymer-based gene delivery, the tuning potential of polymers by using different architectures like graft and star-shaped polymers as well as self-assembled block copolymers is immense. In particular, in the last few years numerous new polymer designs showed enhanced transfection properties in combination with good biocompatibility. Furthermore, new insights into the transfection mechanism demonstrated the continuous progress in this field. Polymer architecture influences the polyplex characteristics and the latter has an impact on the transfection mechanism, e.g. the interaction with the cellular membrane depends on the polyplex shape. Moreover, polyplex dissociation can be easily influenced by the polymer chemistry, thus biodegradable linkers lead to well suited polymers with reduced toxicity and high delivery potential, and are also promising for in vivo applications. This review focuses on the influence of polymer architectures for pDNA transfection in vitro, showing recent developments and insights. The theoretical background concerning the biological challenges for cationic polymers and the impact of graft- or star-shaped architectures as well as self-assembled structures will be presented in detail.

OBJECTIVE Mutations in the cationic trypsinogen (PRSS1), cystic fibrosis transmembrane conductance regulator (CFTR), serine protease inhibitor Kazal type 1 (SPINK1), and chymotrypsin C (CTRC) genes are associated with an elevated risk for chronic pancreatitis, which is a known risk factor for pancreatic cancer (PC). Therefore, we analyzed whether PRSS1, CFTR, SPINK1, and/or CTRC mutations are associated with pancreatic adenocarcinoma. METHODS The study cohort was composed of 121 PC patients, of whom 74 were classified as having chronic pancreatitis, 102 patients with idiopathic chronic pancreatitis, and 130 as healthy controls. Mutation analyses for the CFTR, SPINK1, PRSS1, and CTRC genes were performed for the presence of the most common mutations. RESULTS The frequency of CFTR mutations in patients with PC was not significantly different in comparison with healthy controls and controls with pancreatitis. The SPINK1 mutation frequency was significantly decreased in patients with PC in comparison with patients with idiopathic pancreatitis but varied not significantly in comparison with healthy controls. None of the selected 121 PC samples showed a pancreatitis-predisposing mutation in the PRSS1 or CTRC gene. CONCLUSIONS Mutations in the genes CFTR, SPINK1, PRSS1, and CTRC do not seem to significantly increase the risk for pancreatic adenocarcinoma.

Age-related macular degeneration is the major cause of blindness in the elderly worldwide and the risk is influenced by both environmental and genetic risk factors. One important disease-associated region in humans is located on 10q26 and includes the two candidate genes ARMS2 and HTRA1. However, determination of the causative gene has not yet been possible and examining the situation in the rhesus monkey may help understand the situation in humans. In a recent paper, we characterized the rhesus monkey 10q26-orthologue region on chromosome 9 in detail and identified the drusen-associated HTRA1 promoter SNP rs196357513 as a putative risk factor. In this study, we predicted 9 binding sites for the vitamin D-dependent transcription factor vitamin D receptor in the rhesus HTRA1 promoter, one of which is destroyed by the rs196357513-risk allele. As patients with vitamin D deficit are at increased risk for age-related macular degeneration, a luciferase assay in transiently transfected ARPE19-cells was performed to evaluate the influence of the SNP rs196357513 and of 1,25-dihydroxyvitamin D on the rhesus monkey HTRA1 promoter activity. This revealed that the luciferase activity of the promoter construct containing the rs196357513 wild type allele was significantly reduced after vitamin D stimulation. An in silico analysis and literature search imply that this regulation could also play a role in human HTRA1 expression. Moreover, HTRA1 promoter activity of the construct containing the rs196357513 risk allele appeared diminished in comparison to the construct with the wild type allele, albeit this difference was not significant. The lower promoter activity due to the rhesus monkey rs196357513 risk allele apparently contradicts the common hypothesis for the human HTRA1 promoter risk allele of SNP rs11200638, for which a higher promoter activity has been observed. Our data point to a yet unexpected effect of decreased HTRA1 expression on drusen pathogenesis. Thus not only a higher HTRA1 expression, but an imbalance of HTRA1 might be disease-relevant. Both findings require closer analysis, but if relevance for humans proves true, it would impact current age-related macular degeneration research and treatment.

In recent years, "high-throughput" (HT) has turned into a keyword in polymer research. In this study, we present a novel HT workflow for the investigation of cationic polymers for gene delivery applications. For this purpose, various poly(ethylene imine)s (PEI) were used as representative vectors and investigated via HT-assays in a 96-well plate format, starting from polyplex preparation up to the examination of the transfection process. In detail, automated polyplex preparation, complex size determination, DNA binding affinity, polyplex stability, cytotoxicity, and transfection efficiency were performed in the well plate format. With standard techniques, investigation of the biological properties of polymers is quite time-consuming, so only a limited number of materials and conditions (such as pH, buffer composition, and concentration) can be examined. The approach described here allows many different polymers and parameters to be tested for transfection properties and cytotoxicity, giving faster insights into structure-activity relationships for biological activity.

The current investigation describes in detail the influence of the polymer molar mass as well as polymer-solvent interactions on the formation of nanoparticles using the nanoprecipitation methodology. For this purpose, a homologous series of poly(methyl methacrylate)s with molar masses ranging from 7,700 to 274,000 g mol−1 was prepared. Subsequently nanoprecipitation was performed in an automated and systematic manner using liquid handling robots and a variation of different initial concentrations of the polymers and solvent/nonsolvent ratios. To elucidate information about the polymer behavior in the solvents used for the nanoprecipitation procedure (acetone, tetrahydrofuran), intrinsic viscosity measurements were performed. The nanoparticle formulations were examined in terms of particle size and size distribution, particle shape as well as zeta-potential. The conditions for the preparation of stable and uniform nanoparticles, regardless of molar mass and hydrodynamic volume of the initial polymer, were determined. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

We report a new acid-sensitive, biocompatible, and biodegradable microparticulate delivery system, spermine modified acetalated-dextran (Spermine-Ac-DEX), which can be used to efficiently encapsulate siRNA. These particles demonstrated efficient gene knockdown in HeLa-luc cells with minimal toxicity. This knockdown was comparable to that obtained using Lipofectamine, a commercially available transfection reagent generally limited to in vitro use due to its high toxicity.

The pharmaceutically important polymer P(MAA-r-MMA)(1:2) (EUDRAGIT(®) S100) was investigated concerning its behavior to form nanoparticles via nanoprecipitation. The particles obtained were characterized regarding their size, shape, and characteristics using DLS, SEM, and AUC. Furthermore, the P(MAA-r-MMA)(1:2) copolymer was modified with different markers in order to achieve polymer-based nanocarrier systems, which are detectable and may be useful for controlled drug delivery devices to monitor the drug pathways. The particles were labeled by physical entrapment as well as by covalent attachment of various markers, e.g., radicals, fluorescent-, and near-infrared dyes, to the polymer. Physical entrapment of radicals into the polymeric units was performed by co-nanoprecipitation of P(MAA-r-MMA)(1:2) and a radical marker. By means of covalent binding of the markers to the polymer, a stable and more defined labeling of the particles was also performed, leading only to a low degree of modification of the pharmaceutical polymer. After nanoprecipitation, the resulting labeled particles were characterized by SEM and DLS, whereas their biocompatibility was proven by in vitro studies. In order to ensure the possibility of detection of the particles inside the body for drug delivery-, sensor-, and imaging applications, the polymeric carriers were also investigated by electron spin resonance, fluorescence, as well as near-infrared spectroscopy.

The TSPY gene, which encodes the testis-specific protein, Y-encoded, was first discovered and characterized in humans, but orthologous genes were subsequently identified on the Y chromosome of many other placental mammals. TSPY is expressed in the testis and to a much lesser extent in the prostate gland, and it is assumed that TSPY serves function in spermatogonial proliferation and/or differentiation. It is further supposed that TSPY is involved in male infertility and exerts oncogenic effects in gonadal and prostate tumor formation. As a member of the TSPY/SET/NAP protein family, TSPY is able to bind cyclin B types, and stimulates the cyclin B1-CDK1 kinase activity, thereby accelerating the G2/M phase transition of the cell cycle of target cells. Because the laboratory mouse carries only a nonfunctional Y-chromosomal Tspy-ps pseudogene, a knockout mouse model for functional research analyses is not a feasible approach. In the last decade, three classical transgenic mouse models have been developed to contribute to our understanding of TSPY regulation, expression and function. The different transgenic mouse approaches and their relevance for studying TSPY regulation, expression and function are discussed in this review.

Human TSPY is a candidate oncogene and is supposed to function as a proliferation factor during spermatogenesis. It is the only mammalian protein-coding gene known to be organized as a tandem repeat gene family. It is expressed at highest level in spermatogonia and to a lower amount in primary spermatocytes. To characterize the human TSPY promoter we used the luciferase reporter system in a mouse spermatogonia derived cell line (GC-1spg) and in a GC-4spc cell line, that harbour prophase spermatocytes of the preleptotene and early pachytene stage. We isolated a 1303 bp fragment of the 5′-flanking region of exon 1 that shows significant promoter activity in GC-1spg and reduced activity in GC-4spc cells. In order to gain further insight into the organization of the TSPY-promoter, stepwise truncations of the putative promoter sequence were performed. The resulting fragments were cloned into the pGL3-vector and analysed for reporter gene activity in the murine germ cell lines GC-1spg and GC-4spc, leading to the characterization of a core promoter (−159 to −1), an enhancing region (−673 to −364) and a silencing region (−1262 to −669). Database research for cis-active elements yielded two putative SOX-like binding sites in the enhancing region and reporter gene activity was drastically reduced when three nucleotides of the AACAAT SOX core sequence were mutated. Our findings strongly suggest that testis-specific expression of human TSPY is mediated by Sox proteins. (Mol Cell Biochem 276: 159–167, 2005)

Methacrylate monomers were functionalized with a 4-hydroxythiazole chromophore and copolymerized with methyl methacrylate via RAFT. Nanoparticles of 120 and 500 nm in size were prepared without using stabilizers/surfactants. For comparative studies, preparative ultracentrifugation was applied for the separation into small and large particle fractions. All suspensions were characterized by DLS, AUC, and SEM and tested regarding their stability during centrifugation and re-suspension, autoclavation, and incubation in cell culture media. In vitro studies with mouse fibroblast cell line and differently sized NP showed a particle uptake into cells. Biocompatibility, non-toxicity, and hemocompatibility were demonstrated using a XTT assay, a live/dead staining, and an erythrocyte aggregation and hemolysis assay.

colloidal preceramic materials, Archimedean nanolattices, phosphorescent Ir(III) complexes, self-assembly of a dendritic reactor, synthesis of a heterometallic polymer, synthesis of coordination polymers, preparation of photoluminescent π-conjugated polymers, triazole-pyridine-containing polymers, platinum diketonate-containing polymers, the fabrication of functional nanofi bers, and boron-containing block copolymers for tumor imaging. Utilitarian properties of the investigated polymers include organic batteries, oxygen-resistant phosphorescence, photocatalysis, molecular self-assembly, unimolecular micellar encapsulation, heparin sensing and cellular imaging, and other fascinating topics. Hopefully the journal readership will be sparked to take up the fundamental and applied challenges related to these topics. Enjoy reading this issue! A Pandora’s Box of New Materials— Metallopolymers