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New therapeutic strategies for personalized medicine need to involve innovative pharmaceutical tools, for example, modular nanoparticles designed for direct immunomodulatory properties. We synthesized mannose-functionalized poly(propyleneimine) glycodendrimers with a novel architecture, where freely accessible mannose moieties are presented on poly(ethylene glycol)-based linkers embedded within an open-shell maltose coating. This design enhanced glycodendrimer bioactivity and led to complex functional effects in myeloid cells, with specific induction of interleukin-8 expression by mannose glycodendrimers detected in HL-60 and THP-1 cells. We concentrated on explaining the molecular mechanism of this phenomenon, which turned out to be different in both investigated cell lines: in HL-60 cells, transcriptional activation via AP-1 binding to the promoter predominated, while in THP-1 cells (which initially expressed less IL-8), induction was mediated mainly by mRNA stabilization. The success of directed immunomodulation, with synthetic design guided by assumptions about mannose-modified dendrimers as exogenous regulators of pro-inflammatory chemokine levels, opens new possibilities for designing bioactive nanoparticles.

The poly(propyleneimine) PPI dendrimer with active amino groups and specific voids is an excellent template for the encapsulation and stabilization of size and shape-controlled metal nanoparticles. The magnetite-cored PPI dendrimer up to third generation was synthesized by a divergent method in our previous report. Bimetallic nanoparticles are more advantageous than monometallic nanoparticles in catalysis due to their synergistic effect between two metals, especially Au and Pd nanoparticles. Herein, we present the synthesis of highly monodispersed ultrafine AuPd bimetallic nanoparticles of size 3–6 nm using the magnetic-cored PPI dendrimer through a facile and convenient method without external stabilizers. The formation of the monodispersed bimetallic nanoparticles on the dendritic entity was confirmed through HRTEM, HRSEM, EDAX, XRD, XPS and VSM. The excellent structural behavior of the magnetic-cored PPI dendrimers proves their ability to encapsulate AuPd bimetallic nanoparticles, and also attain better dispersibility, stability, and improved efficacy compared to conventional dendrimer-encapsulated metal nanoparticles. Most predominantly, it was isolated by simple magnetic attraction. The AuPd@PPI@Fe3O4/SiO2 nanomaterial was utilized as a potential green catalyst in the Suzuki coupling reaction under ambient reaction conditions with greater reactivity and stability. Coupling products were characterized by 1H and 13C NMR. This material retained its catalytic activity in the coupling reaction for up to eight consecutive catalytic cycles.

Two third generation liquid-crystalline dendrimers, poly(propyleneimine) derivatives with 3,4-bis(decyloxy)benzoic moieties at the periphery, were prepared, and their thermodynamic properties were studied. The formation of a columnar mesophase was verified by differential scanning calorimetry (DSC) and polarizing optical microscopy. It was for the first time that the specific heat capacity and magnetocaloric effect (MCE) of the iron complex G3-K2.10 ∙ (FeCl2)15 in the temperature 288–350 K in magnetic fields varying from 0 to 1.0 T were determined. The temperature-dependent specific heat capacity of the complexes in the range 210–460 K was measured on a differential scanning calorimeter and an original design microcalorimeter. The temperature-dependent heat capacity and magnetocaloric effect are extreme functions.

Mucosal delivery across the gastrointestinal (GI) tract, airways, and buccal epithelia is an attractive mode of therapeutic administration, but the challenge is to overcome the mucus and epithelial barriers. Here, we present degradable star polypept(o)ides capable of permeating both barriers as a promising biomaterial platform for mucosal delivery. Star polypept(o)ides were obtained by the initiation of benzyl-l-glutamate N-carboxyanhydride (NCA) from an 8-arm poly(propyleneimine) (PPI) dendrimer, with subsequent chain extension with sarcosine NCA. The hydrophobic poly(benzyl-l-glutamate) (PBLG) block length was maintained at 20 monomers, while the length of the hydrophilic poly(sarcosine) (PSar) block ranged from 20-640 monomers to produce star polypept(o)ides with increasing hydrophilic: hydrophobic ratios. Transmission electron microscopy (TEM) images revealed elongated particles of ∼120 nm length, while dynamic light scattering (DLS) provided evidence of a decrease in the size of polymer aggregates in water with increasing poly(sarcosine) block length, with the smallest size obtained for the star PBLG20-b-PSar640. Fluorescein isothiocyanate (FITC)-conjugated PBLG20-b-PSar640 permeated artificial mucus and isolated rat mucus, as well as rat intestinal jejunal tissue mounted in Franz diffusion chambers. An apparent permeability coefficient (Papp) of 15.4 ± 3.1 ×10-6 cm/s for FITC-PBLG20-b-PSar640 was calculated from the transepithelial flux obtained with the apical-side addition of 7.5 mg polypept(o)ide to jejunal tissue over 2 h. This Papp could not be accounted for by flux of unconjugated FITC. Resistance to trypsin demonstrated the stability of FITC-labeled polypept(o)ide over 2 h, but enzymatic degradation at the mucus-epithelial interface or during flux could not be ruled out as contributing to the Papp. The absence of any histological damage to the jejunal tissue during the 2 h exposure suggests that the flux was not associated with overt toxicity.

Linear polyethylenimine (L-PEI) has been the gold standard for gene delivery and is typically prepared by hydrolysis from poly(2-oxazoline)s. Recently, also the anionic polymerization of activated aziridines was reported as a potential pathway toward linear and well-defined polyamines. However, only sulfonamide-activated aziridines so far undergo the living anionic polymerization and their desulfonylation was only reported scarcely. This is mainly due to the relatively high stability of the sulfonamides and the drastic change in solubility during the desulfonylation. Herein, we investigated the desulfonylation of such poly(aziridine)s prepared from tosylated or mesylated propyleneimine to afford linear polypropylenimine (L-PPI) as an alternative to L-PEI. Different desulfonylation strategies for tosylated (Ts) and mesylated (Ms) PPI were studied. The reductive cleavage of the sulfonamide with sodium bis(2-methoxy ethoxy) aluminum hydride yielded 80% of deprotected amine groups. Quantitative conversion to L-PPI was obtained, when the tosylated PPI was hydrolyzed under acidic conditions with

Objective: The aim of the present study leads a comparative assessment of the toxicological profile of PEGylated fourth and fifth-generation poly (propylene imine) dendrimers (PPI). Methods: 4.0G and 5.0G generations of PPI dendrimer were synthesized and PEGylated with Mono polyethylene glycol 5000 (MPEG-5000). Each PEGylated 4.0G and 5.0G dendrimeric generation were administered in three different doses: 2.5 mg/kg, 25 mg/kg and 250 mg/kg (i.e., low, intermediate and high dose) to wister rats. After the dose administration, the blood and tissue samples of wister rats were collected after 24 h and 15 d after. All the collected samples were proceeded for hematological, biochemical and histopathological studies. Results: After 24 h of (250 mg/kg) dose administration PEGylated 5.0G PPI dendrimer the RBC count, hemoglobin content and WBC count were found 7.873±0.129 mill/cmm, 13.833±0.491g/dl and 9033.33±2384.906 mill/cmm, while PEGylated 4.0G PPI dendrimer indicated RBC count, hemoglobin content and WBC count 8.733±0.239 mill/cmm, 14.033±0.12 g/dl and 9666.667±2567.316 mill/cmm, in blood samples as compare to RBC count 9.346±0.037 mill/cmm, hemoglobin content 15.35±0.15 g/dl and WBC count 8500±286.675 mill/cmm of the animals of normal control group. Thus there are no remarkable changes (p>0.05) in RBC count, hemoglobin content and other hematological profile after 24 h in comparison of normal control group of animals. Similarily insignificant changes (p>0.05) in serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), lactate dehydrogenase (LDH) and sections of different organs indicate inoffensive nature of both generations of PEGylated 4.0G and 5.0 G PPI dendrimers. Conclusion: It can be concluded that fifth-generation PPI dendrimers are more suitable as compared to fourth generation of PPI dendrimer, while both dendrimers are not generating any severe toxicity.

Stimuli-responsive nanocarriers have become increasingly important for nucleic acid and drug delivery in cancer therapy. Here, we report the synthesis, characterization and evaluation of disulphide-linked, octadecyl (C18 alkyl) chain-bearing PEGylated generation 3-diaminobutyric polypropylenimine dendrimer-based vesicles (or dendrimersomes) for gene delivery. The lipid-bearing PEGylated dendrimer was successfully synthesized through in situ two-step reaction. It was able to spontaneously self-Assemble into stable, cationic, nanosized vesicles, with low critical aggregation concentration value, and also showed redox-responsiveness in presence of a glutathione concentration similar to that of the cytosolic reducing environment. In addition, it was able to condense more than 70% of DNA at dendrimer: DNA weight ratios of 5 : 1 and higher. This dendriplex resulted in an enhanced cellular uptake of DNA at dendrimer: DNA weight ratios of 10 : 1 and 20 : 1, by up to 16-fold and by up to 28-fold compared with naked DNA in PC-3 and DU145 prostate cancer cell lines respectively. At a dendrimer: DNA weight ratio of 20 : 1, it led to an increase in gene expression in PC-3 and DU145 cells, compared with DAB dendriplex. These octadecyl chain-bearing, PEGylated dendrimer-based vesicles are therefore promising redox-sensitive drug and gene delivery systems for potential applications in combination cancer therapy. This journal is

Rose bengal is an anionic dye considered as a potential photosensitizer for anticancer photodynamic therapy. The clinical utility of rose bengal is hampered by its short half-life, limited transmembrane transport, aggregation, and self-quenching; consequently, efficient drug carriers that overcome these obstacles are urgently required. In this study, we performed multilevel in vitro and in silico characterization of interactions between rose bengal and cationic poly(amidoamine) (PAMAM) and poly(propyleneimine) (PPI) dendrimers of the third and fourth generation and assessed the ability of the resultant complexes to modulate the photosensitizing properties of the drug. We focused on explaining the molecular basis of this phenomenon and proved that the generation- and structure-dependent binding of the dye by the dendrimers increases the cellular uptake and production of singlet oxygen and intracellular reactive oxygen species, leading to an increase in phototoxicity. We conclude that the application of dendrimer carriers could enable the design of efficient photodynamic therapies based on rose bengal.

The synthesis of a novel poly(propyleneimine) (PPI) dendron in gram scale as well as its use in the formation of a highly stable, dendronized gold nanoparticle (AuNP)-based drug delivery platform is described herein. The AuNP-based platform is composed of three complementary parts: (i) a 15 nm AuNP core, (ii) a heterofunctional thioctic acid-terminated tetraethylene glycol spacer, and (iii) a third-generation PPI dendron with a unique protonation profile and diverse end-group functionalization that allows for further derivatization. The prepared dendronized AuNPs are able to withstand several rounds of lyophilization cycles with no sign of aggregation, are stable in phosphate-buffered saline and Hanks’ buffer as well as in serum, and are resistant to degradation by glutathione exchange reactions. This nanocarrier platform displays a dense coating, with >1400 dendrons/AuNPs, which will enable very high payload. Furthermore, while amine-terminated AuNPs expectedly showed cytotoxicity against the MCF-7 breast cancer cell line from a NP concentration of 1 nM, the mixed monolayer AuNPs (coated with 40/60 amine/carboxylate dendrons) interestingly did not exhibit any sign of toxicity at concentrations as high as 15 nM, similar to the carboxylate-terminated AuNPs. The described dendronized AuNPs address the current practical need for a stable NP-based drug delivery platform which is scalable and easily conjugable, has long-term stability in solution, and can be conveniently formulated as a powder and redispersed in desired buffer or serum.

Diglycolamide (DGA)-functionalized poly(propyleneimine) diaminobutane dendrimers of the first (DGA-Den-I) or second (DGA-Den-II) generation and a room temperature ionic liquid (RTIL), viz., 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide, based extraction chromatography resins were prepared for minor actinide separations from high level radioactive waste. The weight distribution coefficients (Kd) of actinides on the two resins gave excellent and selective sorption of Am(III) and Pu(IV) over hexavalent uranyl ions, Sr(II) and Cs(I), over a wide range of acidity (0.01-6 M HNO3). The sorbed Am(III) and Pu(IV) could be efficiently desorbed with a buffered complexing solution of 1 M guanidine carbonate + 0.05 M EDTA. The sorption of metal ions on both the resins followed pseudo-second order rate kinetics and proceeded via a chemisorption phenomenon with a sorption energy of 13.4 ± 0.2 kJ/mol. The resin capacities were estimated to be 4.64 ± 0.18 and 4.19 ± 0.21 mg of Eu per g of DGA-Den-I and DGA-Den-II resins, respectively. The column loading of Eu(III) was about 85% of the theoretical value with a narrow elution profile using a buffered complexing solution. The resin affinity toward U(VI), Sr(II), and Cs(I) cations over Am(III) and Pu(IV) was poor, indicating the possible use of the resins for selective separation of Am(III) and Pu(IV) from other metal ions over a wide range of feed acidity.

Context: Polypropylenimine (PPI), a cationic dendrimer with defined structure and positive surface charge, is a potent non-viral vector. Dexamethasone (Dexa) conveys to the nucleus through interaction with its intracellular receptor. Objective: This study develops efficient and non-toxic gene carriers through conjugation of Dexa at various percentages (5, 10 and 20%) to the fourth and the fifth generation PPIs (PPIG4s and PPIG5s). Materials and methods: The 21-OH group of Dexa (0.536 mmol) was modified with methanesulfonyl chloride (0.644 mmol) to activate it (Dexa-mesylate), and then it was conjugated to PPIs using Traut's reagent. After dialysis (48 h) and lyophilization, the physicochemical characteristics of products (PPI-Dexa) including zeta potential, size, buffering capacity and DNA condensing capability were investigated and compared with unmodified PPIs. Moreover, the cytotoxicity and transfection activity of the Dexa-modified PPIs were assessed using Neuro2A cells. Results: Transfection of PPIG4 was close to PEI 25 kDa. Although the addition of Dexa to PPIG4s did not improve their transfection, their cytotoxicity was improved; especially in the carrier to DNA weight ratios (C/P) of one and two. The Dexa conjugation to PPIG5s enhanced their transfection at C/P ratio of one in both 5% (1.3-fold) and 10% (1.6-fold) Dexa grafting, of which the best result was observed in PPIG5-Dexa 10% at C/P ratio of one. Discussion and conclusions: The modification of PPIs with Dexa is a promising approach to improve their cytotoxicity and transfection. The higher optimization of physicochemical characteristics, the better cell transfection and toxicity will be achieved.

Nanometer-scale gold particles exhibit size-dependent electronic properties with important sensing and biosensing applications. In the same way, a lot of analytes show some type of surface-sensitive reaction and the electrode material has a strong influence on the catalytic activity. In this work we study the kinetics and electrochemistry of electrodes with size controlled gold nanoparticles, obtained by electrodeposited amidoferrocenylpoly(propyleneimine) dendrimers of two generations as templates, and the kinetics and the analytical response to the oxidation of dopamine. We demonstrate that the four-types of modified electrodes show good catalytic responses toward the oxidation of dopamine via different processes in relation with the absence or presence of gold nanoparticles and their size. The best response was obtained with the largest nanoparticles, obtained with the first generation dendrimer-template at 0.3 V vs. SCE, with three linear ranges (0–70, 70–600 and 600–1000 μM), with sensitivities 585.7; 466.0 and 314.3 μA/mM cm 2 , and limit of detection of 0.01 μM. The effect of interfering substances has been studied by differential pulse voltammetry and the developed sensor has been successfully used for the determination of dopamine in a commercial dopamine hydrochloride injection and in spiked Human urine.

Poly(propyleneimine) dendrimers of fourth generation partially modified with maltose (open shell structure, PPI-m OS) have been proposed as carriers for nucleotide anticancer drugs. The aim of this work was to provide basic insight into interactions between fluorescently labeled PPI-m dendrimer and two distinct leukemia cell models: CCRF-1301 lymphoid cell line and HL-60 myeloid cell line. We applied qualitative confocal imaging and quantitative flow cytometry, as well as trypan blue quenching and pharmacological inhibition, to investigate the course, kinetics, and molecular mechanisms of internalization of nanoparticles. CCRF-1301 cells take up glycodendrimer macromolecules via a relatively slow, adsorptive endocytosis process, which is cholesterol-dependent, clathrin- and caveolin-independent, and not followed by recycling or exocytosis. Morphological features of this phenomenon point to the involvement of aggregation-induced cell polarity changes (capping). In HL-60 cells, internalization is very fast, independent of binding to the cell surface, and proceeds from the fluid phase via a classical clathrin-dependent mechanism, ending up in an endolysosomal compartment from which it is not further released. This substantial difference in internalization rate and mechanism between two cell types has important repercussions for potential application of this class of glycodendrimers as drug delivery agents.

Dendrimer nanostructures are of eminent interest in biomedical applications because of their uniform and well-defined molecular size and shape, and their ability to cross cell membranes and reduce the risk of premature clearance from the human body. Dendrimers perform as gene and drug carriers and have also shown significant therapeutic properties for treating cancer and neurodegenerative diseases. A complex drug delivery system, based on a dendrimer solubilized in the aqueous core of a water-in-oil (W/O) microemulsion (ME) along with the drug may combine the advantages of both dendrimers and MEs to provide better control of drug release. We propose a new microemulsion composed of drug-permitted surfactants and dendrimer that can be used as a potential controlled drug delivery nanosystem. The influence of second generation poly(propyleneimine) (PPI-G2) dendrimer; solubilized in (W/O) ME with a capacity of up to 25 wt% PPI-G2 at various pHs; and their interactions with the surfactant phosphatidylcholine (PC), cosurfactant (butanol), and water was studied. SAXS and EPR measurements indicated that increasing PPI-G2 concentration reduces droplet curvature and increases droplet size thus increasing macro-(SAXS) and micro-(EPR) order degree. Furthermore, SD-NMR and ATR-FTIR show stronger interactions between PPI-G2 and water molecules at the expense of PC and butanol headgroups hydration, which increases microviscosity (EPR). PPI-G2's effect is somewhat opposite to the increasing water phase effect, thus reducing the amount of free water (DSC) and slowing the mobility of all ME components (SD-NMR).

Poly(propyleneimine) glycodendrimers are proposed as nanocarriers for triphosphate forms of anticancer adenosine analogues to improve the efficiency of chemotherapy and to overcome drug resistance mechanisms. This approach has proven successful for fludarabine administration-an autonomous way of cellular entry of a nucleotide-dendrimer noncovalent complex enables an increase in the intracellular accumulation and cytotoxic activity of the active metabolite of the drug. However, the attempt to apply an analogous strategy for clofarabine results in the inhibition of drug activity. To better understand this phenomenon, characterization and comparison of drug-dendrimer complexes were needed to indicate the differences in their surface properties and the strengths of fludarabine-dendrimer and clofarabine-dendrimer interactions. Here, zeta potential measurements, ultrafiltration, and asymmetric flow field-flow fractionation are applied to determine the surface electrostatic potential and stability of nucleotide-dendrimer formulations. This approach significantly extends the authors' research on the complexation potential of perfectly branched macromolecules, ultimately explaining previously observed differences and their consequences.

Omega fatty acids, mainly the triglyceride of docosahexaenoic acid (TG-DHA), are considered important nutraceuticals. These compounds are water-insoluble and their transport across membranes depends on their carriers. Dendrimers are known as drug carriers across cell membranes and also as permeation enhancers. The solubilization of TG-DHA and dendrimer into a microemulsion (ME) system serving as a carrier could be used for a targeted delivery in the future. The interactions between TG-DHA and second generation poly(propyleneimine) dendrimers (PPI-G2) and their effect on structural transitions of ME were explored along the water dilution line using electron paramagnetic resonance and pulsed-gradient spin-echo NMR along with other analytical techniques. The microviscosity, order parameter, and micropolarity of all studied systems decrease upon water dilution. Incorporation of TG-DHA reduces the microviscosity, order, and micropolarity, whereas PPI-G2 leads to an increase in these parameters. The effect of PPI-G2 is more pronounced at relative high contents (1 and 5wt%) where PPI-G2 interacts with the hydrophilic headgroups of the surfactants. In the macroscale, the effects of TG-DHA and PPI-G2 differ mostly in the bicontinuous region, where macroviscosity increases upon TG-DHA incorporation and decreases upon solubilization of 5wt% PPI-G2. From DSC measurements it was concluded that in the presence of TG-DHA the PPI-G2 is intercalated easily at the interface.

The present investigation was aimed at developing various ligands-anchored dendrimers and comparing their brain targeting potential at one platform. Sialic acid (S), glucosamine (G) and concanavalin A (C) anchored poly(propyleneimine) (PPI) dendritic nanoconjugates were developed and evaluated for delivery of anti-cancer drug, paclitaxel (PTX) to the brain. MTT assay on U373MG human astrocytoma cells indicated IC50 values of 0.40, 0.65, 0.95, 2.00 and 3.50μM for PTX loaded SPPI, GPPI, CPPI, PPI formulations, and free PTX, respectively. The invivo pharmacokinetics and biodistribution studies in rats showed significantly higher accumulation of PTX in brain as compared to free PTX. The order of targeting potential of various ligands under investigation was found as sialic acid>glucosamine>concanavalin A. Thus, it can be concluded that sialic acid, glucosamine and Con A can be used as potential ligands to append PPI dendrimers for enhanced delivery of anticancer drugs to the brain for higher therapeutic outcome.

Results of zeta potential measurements and of spectroscopic (increased solubility, equilibrium dialysis, 1H NMR titration) and calorimetric measurements (isothermal ITC titration) indicate that fourth generation poly(propyleneimine) dendrimer (PPI G4) spontaneously binds (∆G

The conventional method of dendrimer synthesis especially poly(propyleneimine) dendrimer (PPI) involves complicated reaction workup and tedious separation strategies. Since it has greater number of nitrogen atom in their structure, its applications are innumerable in different fields. But the PPI dendrimer is used once, it cannot be recycled for subsequent utility. In order to overcome these issues, for the first time divergent synthesis of poly(propyleneimine) dendrimer G3 on silica coated magnetite has been achieved with structurally enhanced PPI dendrimer on core-shell type magnetic silica nanostructure. This nanohybrid material was characterized by using HRTEM, FTIR, XRD, TGA, XPS and VSM studies. Further, nitrogen concentration of PPI dendrimer was quantified by conductometric titration and Prussian blue complex methods. The probing of catalytic efficacy of structurally enhanced magnetite cored poly(propyleneimine) dendrimer G3 as magnetically recyclable heterogeneous organic base catalyst was employed for representative reactions such as Knoevenagel condensation, Knoevenagel-Michael cyclocondensation and Henry reaction at ambient conditions. The catalyst was reused for minimum of eight cycles without significant loss of its catalytic activity.

Fludarabine is an anticancer antimetabolite essential for modern chemotherapy, but its efficacy is limited due to the complex pharmacokinetics. We demonstrated the potential use of maltose-modified poly(propyleneimine) dendrimer as drug delivery agent to improve the efficiency of therapy with fludarabine. In this study, we elaborated a novel synthesis technique for radioactively labeled fludarabine triphosphate to prove for the first time the direct ability of nucleotide-glycodendrimer complex to enter and kill leukemic cells, without the involvement of membrane nucleoside transporters and intracellular kinases. This will potentially allow to bypass the most common drug resistance mechanisms observed in the clinical setting. Further, we applied surface plasmon resonance and molecular modeling to elucidate the properties of the drug-dendrimer complexes. We showed that clofarabine, a more toxic nucleoside analogue drug, is characterized by significantly different molecular interactions with poly(propyleneimine) dendrimers than fludarabine, leading to different cellular outcomes (decreased rather than increased treatment efficiency). The most probable mechanistic explanation of uniquely dendrimer-enhanced fludarabine toxicity points to a crucial role of both an alternative cellular uptake pathway and the avoidance of intracellular phosphorylation of nucleoside drug form.

Nowadays, the researchers make a big effort to find new alternatives to overcome bacterial drug resistance. One option is the application of bacteriophage endolysins enable to degrade peptidoglycan (PG) what in consequence leads to bacterial cell lysis. In this study we examine phage KP27 endolysin mixed with poly(propyleneimine) dendrimers to evaluate an antimicrobial effect against Pseudomonas aeruginosa. Polycationic compounds destabilize bacterial outer membrane (OM) helping endolysins to gain access to PG. We found out that not only bacterial lipopolysaccharide (LPS) is the main hindrance for highly charged cationic dendrimers to disrupt OM and make endolysin reaching the target but also the dendrimer surface modification. The reduction of a positive charge and concentration in maltose poly(propyleneimine) dendrimers significantly increased an antibacterial effect of endolysin. The application of recombinant lysins against Gram-negative bacteria is one of the future therapy options, thus OM permeabilizers such as cationic dendrimers may be of high interest to be combined with PG-degrading enzymes.

Poly(propyleneimine) dendrimers fully surface-modified with disaccharide moieties (maltose, cellobiose, and lactose) designed to mimic natural lectin receptor ligands were tested for their bioactivity in two myeloid cell lines: THP-1 and HL-60. Depending on the sugar modification, we observed variable activation of NF-κB, AP-1, and NF-AT signaling pathways: lactose-coated dendrimers had the strongest impact on marker gene expression and most signaling events with the notable exception of NF-κB activation in THP-1 cells. The two cell lines showed an overall similar pattern of transcription factor and gene expression activation upon treatment with glycodendrimers, suggesting the involvement of galectin and C-type lectin receptor types. An important result of this action was the overexpression of CD40 and IL8 genes, potentially leading to an activated, proinflammatory phenotype in the monocyte/macrophage cell lineage. These pharmacodynamic characteristics of glycodendrimers need to be taken into account during their pharmaceutical applications both in drug delivery and direct immunomodulation.

Acrylate pressure sensitive adhesive (PSA) latexes were synthesized via a starved monomer seeded semi-batch emulsion polymerization process with butyl acrylate (BA), methyl methacrylate (MMA), acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA). These PSA polymers were then cross-linked with trifunctional propyleneimine external cross-linker (SAC-100) to study the cross-linking reaction between carboxylic group of the polymer chain and cross-linking agent. It was found that cross-linking provided a significant influence on the film formation process based on the result of SEM analysis. In addition, with the increase of SAC-100 content, the gel content of the polymer increased significantly, while molecular weight between cross-link points (Mc) and the sol molecular weight (Mw, Mn) of the polymer decreased remarkably. The TGA result showed that the addition of the external cross-linker can enhance the thermal stability of the latex film. Moreover, for the cross-linked adhesive film, the shear strength was improved greatly while at the sacrifice of loop tack and peel strength, when compared with the uncross-linked counterparts. Besides, dynamic mechanical analysis (DMA) was also used to evaluate the viscoelastic properties of the acrylate emulsion PSA film.

The success of any drug delivery carrier strictly depends on its toxicological profile. Apart from huge drug delivery potential of dendrimers, toxicity associated with their positively charged surfaces, constrains their biomedical applications. Engineering of these surfaces with targeting ligands not only diminishes their toxicity but also enhances the targeting potential. Conjugation of folate on the surface of poly(propyleneimine) (PPI) dendrimers is widely explored concept. The present paper investigated generation-dependent hemolytic toxicity of folate anchored PPI dendrimer (FA-PPI3, FA-PPI4 and FA-PPI5) at different concentrations (0.1–0.5% w/v ). Further the effect of folate engineered PPI dendrimers on the surface morphology of human erythrocytes and hematological parameters was also observed. In the final outcome the extent of hemolysis was found to be concentration as well as generation dependent.

This paper describes a novel strategy for targeted delivery of amphotericin B (AmB) to macrophages with muramyl dipeptide (MDP) conjugated multimeric poly(propyleneimine) (PPI) dendrimers. Synergistic antiparasitic activity due to immunostimulation by multimeric presentation of MDP on dendrimers was anticipated. MDP conjugated 5.0G PPI (MdPPI) dendrimers were synthesized and characterized. Therapeutic activity and toxicity of dendrimeric formulation of AmB (MdPPIA) were compared with marketed formulations of AmB. Highly significant (P0.01) reduction in toxicity was observed in hemolytic toxicity and cytotoxicity studies in erythrocytes and J774A.1 macrophage cells, respectively. Formulation MdPPIA showed appreciable macrophage targeting potential and higher or equivalent antiparasitic activity against parasite infected macrophage cell lines and in vivo infection in Balb/c mice. These results suggest the developed MDP conjugated dendrimeric formulation of AmB as a promising immunostimulant targeted drug delivery system and a safer alternative to marketed formulations. From the clinical editor: Parasitic infections remain a significant issue in the clinical setting. The authors in this article studied the use of ligand anchored dendrimeric formulation of Amphotericin B to target infected macrophages and showed reduced toxicity, high anti-leishmanial activity. This may add another treatment option to available formulations in the future.

Fludarabine, a nucleoside analogue antimetabolite, has complicated pharmacokinetics requiring facilitated transmembrane transport and intracellular conversion to triphosphate nucleotide form (Ara-FATP), causing it to be susceptible to emergence of drug resistance. We are testing a promising strategy to improve its clinical efficacy by direct delivery of Ara-FATP utilizing a biocompatible glycodendrimer nanocarrier system. Here, we present results of a proof-of-concept experiment in several in vitro-cultured leukemic cell lines (CCRF, THP-1, U937) using noncovalent complexes of maltose-modified poly(propyleneimine) dendrimer and fludarabine triphosphate. We show that Ara-FATP has limited cytotoxic activity toward investigated cells relative to free nucleoside (Ara-FA), but complexation with the glycodendrimer (which does not otherwise influence cellular metabolism) drastically increases its toxicity. Moreover, we show that transport via hENT1 is a limiting step in Ara-FA toxicity, while complexation with dendrimer allows Ara-FATP to kill cells even in the presence of a hENT1 inhibitor. Thus, the use of glycodendrimers for drug delivery would allow us to circumvent naturally occurring drug resistance due to decreased transporter activity. Finally, we demonstrate that complex formation does not change the advantageous multifactorial intracellular pharmacodynamics of Ara-FATP, preserving its high capability to inhibit DNA and RNA synthesis and induce apoptosis via the intrinsic pathway. In comparison to other nucleoside analogue drugs, fludarabine is hereby demonstrated to be an optimal candidate for maltose glycodendrimer-mediated drug delivery in antileukemic therapy.

This work aims to provide an effective and novel solution for the treatment of infection by using nanovehicles loaded with antibiotics capable of penetrating the bacterial wall, thus increasing the antimicrobial effectiveness. These nanosystems, named "nanoantibiotics", are composed of mesoporous silica nanoparticles (MSNs), which act as nanocarriers of an antimicrobial agent (levofloxacin, LEVO) localized inside the mesopores. To provide the nanosystem of bacterial membrane interaction capability, a polycationic dendrimer, concretely the poly(propyleneimine) dendrimer of third generation (G3), was covalently grafted to the external surface of the LEVO-loaded MSNs. After physicochemical characterization of this nanoantibiotic, the release kinetics of LEVO and the antimicrobial efficacy of each released dosage were evaluated. Besides, internalization studies of the MSNs functionalized with the G3 dendrimer were carried out, showing a high penetrability throughout Gram-negative bacterial membranes. This work evidences that the synergistic combination of polycationic dendrimers as bacterial membrane permeabilization agents with LEVO-loaded MSNs triggers an efficient antimicrobial effect on Gram-negative bacterial biofilm. These positive results open up very promising expectations for their potential application in new infection therapies., 33 pages, 6 figures

[60]Fulleropyrrolidine-containing poly(benzyl ether) dendrimers 1−4 were synthesized via 1,3-dipolar cycloaddition of amino acid and aldehyde derivatives and [60]fullerene. Their dielectric and electrooptical (Kerr effect) solution properties were studied and compared with poly(propyleneimine) dendrimers, namely DAB-dendr-(alkyl chain)n and DAB-dendr-(CN)n, and with known symmetrical and non-symmetrical poly(benzyl ether) dendrimers carrying benzyl groups ([Gx]-[C]-[Gx]) or benzyl and cyanobenzyl groups (CNn-[Gx]-[C]-[Gx+1]), respectively. It was shown that 1−4 display similar polar and electrooptical characteristics independent of their dendrimer generation. This is in contrast to the reference dendrimers for which a strong dependence of total dipole moment on dendrimer generation was observed.

The development of cyclometalated rhodium and iridium complexes from first-and second-generation naphthaldimine-based poly(propyleneimine) dendrimer scaffolds of the type, DAB-(NH2)(n) (where n = 4 or 8, DAB = diaminobutane) has been accomplished. Four metallodendrimers were synthesised, viz. (Cp*MCl)(4)G(n) (1-4), by first reacting DAB-(NH2)(n) with napththaldehyde and subsequently metallating the Schiff-base dendrimers with the dimers [Cp*MCl2](2) (where M = Rh or Ir). Related mononuclear complexes [Cp*MCl(L)] (L = naphthaldimine) (5-6) were obtained in a similar manner. The molecular structures of 5 and 6 have been determined by single-crystal X-ray diffraction analysis and the in vitro anticancer activities of 1-6 were evaluated against the A2780 and A2780cisR human ovarian carcinoma cell lines. (C) 2014 Elsevier B.V. All rights reserved.

Folate conjugated poly(propyleneimine) (PPI) dendrimer (FPPI) mediated anticancer therapy is being extensively discovered throughout the world. The present investigation was aimed at exploring the targeting potential of Melphalan loaded FPPI of different generations (MP-FPPI) for effective management of cancer. The MP-FPPI formulations were compared for drug entrapment efficiency, in vitro release profile, toxicology, folate receptor blockage assay, cell uptake assay, stability studies, and in vivo studies. Upon increasing the dendrimer generation from fourth to fifth, the drug delivery parameters improved negligibly except the toxicological profile that improved exponentially. MTT assay in case of MCF-7 cells depicted the IC 50 values of 8 ± 0.15, 0.9 ± 0.02, 0.2 ± 0.01 and 10 ± 0.17 μM, respectively in case of MP-FPPI3, MP-FPPI4, MP-FPPI5, and free Melphalan suggesting folate based targeting to be the efficacious approach to kill cancer cells. The median survival time for tumor bearing mice treated with MP-FPPI3, MP-FPPI4, MP-FPPI5 and free drug was found to be 23, 59, 62 and 26 days, respectively. The study concludes fourth generation PPI dendrimer to be superior carrier for folate based tumor targeting compared to third and fifth generation based formulations. This work is expected to provide a significant clue in the selection of “dendrimer generation” for folate mediated cancer targeting therapy.

Aim: In spite of numerous biopharmaceutical applications of fifth-generation poly(propyleneimine) (PPI) dendrimers, inherent toxicity due to the presence of many peripheral cationic groups is the major issue that limits their applicability. Maximum biocompatibility with minimal toxicity is the key rationale for an ideal drug-delivery system. Keeping this principle in mind, the present investigation aimed to explore the tumor-targeting potential of folate-engineered fourth-generation PPI dendrimers loaded with an anticancer drug, melphalan. Materials & methods: Fourth-generation PPI as well as folate-conjugated fourth-generation PPI dendrimers were synthesized, characterized and loaded with melphalan. Results: Hemolytic toxicity, cytotoxicity, cellular uptake and fluorescence uptake studies reveal that the developed folate-conjugated derivative has significantly lower toxicity, as well as demonstrates folate receptor specificity. Discussion & conclusion: The developed nanoconjugates appear to be proficient in carrying as well as site-specific delivery of melphalan, with an improved therapeutic margin and improved safety. Original submitted 11 July 2013; Revised submitted 11 November 2013

Four first- and second-generation heterometallic ferrocenyl derived p-cymene-Ru(II) metallodendrimers, of general formula [DAB-PPI{(η6-p-cymene)Ru((C7H5NO)-κ2-N,O)PTA(5-ferrocenylvinyl)}n][PF6]n and [DAB-PPI{(η6-p-cymene)Ru((C6H5N2)-κ2-N,N)Cl(5-ferrocenylvinyl)}n][PF6]n (where n = 4 (G1), 8 (G2), DAB = 1,4-diaminobutane, PPI = poly(propyleneimine), PTA = 1,3,5-triaza-7-phosphatricyclo[3.3.1.1]decane) have been synthesized. All complexes have been characterized using analytical (i.e., HR-ESI mass spectrometry, HPLC, elemental analysis, and cyclic voltammetry) and spectroscopic (i.e., 1H and 13C{1H} NMR and infrared) methods. Electrochemical studies reveal that the N,O-p-cymene-Ru(II)-PTA complexes result in two irreversible redox processes (oxidation of the Fe(II) and Ru(II) centers), while the N,N-p-cymene-Ru(II) complexes display one reversible wave (Fe(II)/Fe(III) couple). Heterometallic model complexes have been prepared, and for one of the complexes, its molecular structure has been determined by sing...

In this study, multiwalled carbon nanotubes were successfully modified using poly propyleneimine dendrimer. Structural characterization of the newly synthesized adsorbent confirmed the modification of nanotubes by dendrimer molecules. In order to evaluate the performance of this novel adsorbent for the removal of two direct dyes from textile wastewaters, the effect of important parameters including pH, initial dye concentration, adsorbent dosage, and inorganic salts was investigated in single and binary dye solutions. Response surface methodology was employed to find the relation between the effective parameters and dye removal efficiency. The adsorption process was optimized to reach the dye removal of 95% using response optimizer. The prepared adsorbent showed excellent adsorption behavior toward the anionic dye molecules, and the dye removal efficiencies of nanotubes were significantly improved from 17.7% to 99.9% after their modification with dendrimer. Also, the desorption tests revealed the maximum ...

Dendrimer-mediated delivery of bioactive is a successful and widely explored concept. This paper desribes comparative data pertaining to generation dependent cancer targeting propensity of Poly(propyleneimine) (PPI) dendrimers. This debut report reportsthe drug targeting and antciancer potential of different dendrimer generations. PPI dendrimers of different generations (3.0G, 4.0G and 5.0G) were synthesized and loaded with Melphalan. Results from loading, hemolysis, hematologic, cytotoxicty and flow cytometry assay depicted that as the generation of dendrimer increased from fourth to fifth, the only parameter i.e. toxicty is increased exponentionally. However, others parameters, i.e. loading, sustained release behavior, and targeting efficacy increased negligibly. Kaplan-Meier survival curves clearly depicted comparable therapeutic potential of PPI4M with PPI5M. In vivo investigations in Balb/c mice again favored 4.0G PPI dendrimer to be preferable nanocarrier for anticancer drug delivery owing to analogous anticancer potential. The outcomes of the investigation evidently projects 4.0G PPI dendrimer over 3.0G and 5.0G dendrimer in respect of its drug delivery benefit as well as superior biocompatibility. Thus, much against the common belief, 4.0G PPI dendrimers may be considered to be optimum in respect of drug delivery precluding the use of much more toxic 5.0G PPI dendrimer, which offers no benefit over 4.0G.

We investigate the interactions of generation 3 (G3) poly(amidoamine) (PAMAM) and G3 poly(propylenimine) (PPI) dendrimers with sodium dodecyl sulfate (SDS) in aqueous solution. Size and structure of the dendrimer-SDS aggregates as a function of SDS/dendrimer molar ratio were revealed by SAXS and NMR. G3 PAMAM has a relatively open and dense-core structure, while G3 PPI with the same number of surface amine groups possesses a compact and uniform structure. Upon addition of SDS, much more SDS monomers were encapsulated in the interior of PPI rather than in PAMAM. More significant size increase in PAMAM-SDS aggregate is observed at low SDS concentrations, due to the binding of SDS on PAMAM surface and further assembly into larger supramolecular structures. Both noncooperative and cooperative binding of SDS on G3 PPI surface are observed, while only noncooperative binding is proposed on G3 PAMAM, due to its open surface and large surface group distance. The size of the PPI-SDS complex is larger than that of PAMAM-SDS at higher SDS concentrations. Within the investigated SDS concentrations, SDS exhibits much stronger interactions with G3 PPI than with G3 PAMAM. These results provide new insights into dendrimer-surfactant interactions and explain why PPI is much more cytotoxic than PAMAM.

Tertiary amine containing poly(propyleneimine) second (G2) and third (G3) generation dendrimers as well as polyethyleneimine (PEI) were developed for the selective removal of SO2. N-Alkylation of primary and secondary amines into tertiary amines was confirmed by FTIR and NMR analysis. Such modified polyamines were impregnated on two nanoporous supports, namely, SBA-15PL silica with platelet morphology and ethanol-extracted pore-expanded MCM-41 (PME) composite. In the presence of 0.1% SO2/N2 at 23 °C, the uptake of modified PEI, G2, and G3 supported on SBA-15PL was 2.07, 2.35, and 1.71 mmol/g, respectively; corresponding to SO2/N ratios of 0.22, 0.4, and 0.3. Under the same conditions, the SO2 adsorption capacity of PME-supported modified PEI and G3 was significantly higher, reaching 4.68 and 4.34 mmol/g, corresponding to SO2/N ratios of 0.41 and 0.82, respectively. The working SO2 adsorption capacity decreased with increasing temperature, reflecting the exothermic nature of the process. The adsorption capacity of these materials was enhanced dramatically in the presence of humidity in the gas mixture. FTIR data before SO2 adsorption and after adsorption and regeneration did not indicate any change in the materials. Nonetheless, the SO2 working capacity decreased in consecutive adsorption/regeneration cycles due to evaporation of impregnated polyamines, rather than actual deactivation. FTIR and (13)C and (15)N CP-MAS NMR of fresh and SO2 adsorbed modified G3 on PME confirmed the formation of a complexation adduct.

Four types of new multi-walled carbon nanotube (MWCNT) based nanohybrid catalysts were prepared through simple methods. Initially, MWCNT was functionalized with carboxyl group and subsequently bonded with amphiphilic poly(propyleneimine) dendrimer (APPI) having generation (G2) and (G3). They are abbreviated as MWCNT-APPI (G2) and MWCNT-APPI (G3). Silver nanoparticles (AgNPs) and palladium nanoparticles (PdNPs) were separately immobilized to each hybrid to obtain four types of MWCNT based nanohybrid catalysts. The pseudo-first order rate constants for reduction of 4-nitrophenol revealed that among the four types of MWCNT nanohybrid catalysts, MWCNT-APPI (G3)-PdNPs was more efficient than the other catalysts with five-fold higher efficiency than the homogeneous PPI (G3)-PdNPs. For the same reaction with MWCNTs-APPI (G3)-PdNPs catalyst, the variation of [catalyst] and [NaBH4] was directly proportional to kobs. The study of reusability of MWCNT-APPI (G3)-PdNPs proved no loss in activity even after recycling the catalyst for five times.

The development of multinuclear pentamethylcyclopentadienyl (Cp*) rhodium and iridium complexes from first- and second-generation 2-iminopyridyl and salicylaldimine based poly(propyleneimine) dendrimer scaffolds of the type, DAB-(NH2)n (n = 4 or 8, DAB = diaminobutane) has been accomplished. Eight compounds were synthesised, viz. (Cp*MCl)4Gn (1–8), by first reacting DAB-(NH2)n with either 2-pyridinecarboxaldehyde or salicylaldehyde and subsequently metallating the Schiff-base dendrimers with [Cp*MCl2]2 (where M = Rh, Ir). Related mononuclear complexes [Cp*MCl(L)] (L = iminopyridyl or salicylaldimine) (9–12) were obtained in a similar manner. The molecular structures of 9–12 have been determined by single-crystal X-ray diffraction analysis and the in vitro anticancer activities of 1–12 were evaluated against the A2780 and A2780cisR human ovarian carcinoma cell lines.

The present investigation was aimed at exploring dual targeting of anti-HIV drug, zidovudine (ZDV) via sialic acid conjugated-mannosylated poly(propyleneimine) (PPI) dendritic nano-constructs. Fourth generation PPI dendrimers, sialic acid conjugated PPI dendrimers (SPPI), mannose conjugated PPI dendrimers (MPPI) and dual ligand system i.e. sialic acid conjugated-mannosylated PPI dendrimers (SMPPI) were synthesized and characterized by FT-IR and (1)H NMR spectroscopies and were further confirmed by size exclusion chromatography and differential scanning calorimetry. Various parameters like drug loading, pH dependent in vitro release, hemolytic toxicity, macrophage uptake and cytotoxicity concerning PPI, SPPI, MPPI and SMPPI dendrimers were evaluated. ZDV loaded SMPPI, SPPI and MPPI have shown reduced hemolytic toxicity, cytotoxicity and in vitro drug release at pH 7.4. Extremely significant (P0.001) increase in cellular uptake of ZDV by macrophage cells was observed in case of SMPPI as compared to PPI and free drug. The in vivo blood level and tissue distribution studies in albino rats also demonstrated potential of dual targeted system towards sialoadhesin and carbohydrate receptors. The drug concentration in lymph nodes was increased to about 28 times in case of SMPPI (1335 ± 17.6 ng/g) as compared to free drug (48 ± 5.8 ng/g) at 6th hr. The results suggested that such dual ligand dendritic system (SMPPI) hold potential to enhance biocompatibility and site specific delivery of antiretroviral drug, ZDV.

The applications of dendrimer-based vectors seem to be promising in non-viral gene delivery because of their potential for addressing the problems with viral vectors. In this study, generation 3 poly(propyleneimine) (G3-PPI) dendrimers with 1, 4-diaminobutane as a core initiator was synthesized using a divergent growth approach. To increase the hydrophobicity and reduce toxicity, 10% of primary amines of G3-PPI dendrimers were replaced with bromoalkylcarboxylates with different chain lengths (6-bromohexanoic and 10-bromodecanoic). Then, to retain the overall buffering capacity and enhance transfection, the alkylcarboxylate–PPIs were conjugated to 10 kDa branched polyethylenimine (PEI). The results showed that the modified PPI was able to form complexes with the diameter of less than 60 nm with net-positive surface charge around 20 mV. No significant toxicity was observed in modified PPIs; however, the hexanoate conjugated PPI–PEI (PPI-HEX-10% PEI) and the decanoate conjugated PPI–PEI (PPI-DEC-10%-PEI) showed the best transfection efficiency in murine neuroblastoma (Neuro-2a) cell line, even PPI-HEX-10%-PEI showed transfection efficiency equal to standard PEI 25 kDa with reduced toxicity. This study suggested a new series of hyperbranched (PEI)–dendrimer (PPI) architectural copolymers as non-viral gene delivery vectors with high transfection efficiency and low toxicity.

Poly(propyleneimine) glycodendrimers fully modified with maltose units were administered to different cancer cell lines and their effect on cell viability was evaluated by using MTS assay and flow cytometry. The mechanism of dendrimer-cell interactions was investigated by the electron paramagnetic resonance (EPR) technique by using a new nitroxide-conjugated glycodendrimer. The nitroxide groups did not modify both the biological properties (cell viability and apoptosis degree) of the dendrimers in the presence of the cells and the dendrimer-cell interactions. Since this class of dendrimers is already known to be biocompatible for human healthy cells, noncancer cells such as human peripheral blood mononuclear cells (PBMCs) and macrophages were also treated with the glycodendrimer, and EPR spectra of the nitroxide-conjugated glycodendrimer were compared for cancer and noncancer cells. It was found that this dendrimer selectively affects the cell viability of tumor cells, while, surprisingly, PBMC proliferation is induced. Moreover, H-bond-active glycodendrimer-cell interactions were different for the different cancer cell lines and noncancer cells. The nitroxide-conjugated glycodendrimer was able to interact with the cell membrane and eventually cross it, getting in contact with cytosol antioxidants. This study helps to clarify the potential anticancer effect of this class of dendrimers opening to future applications of these macromolecules as new antitumor agents.

Acrylonitrile-modified aliphatic amine adducts are often used as curing agents for room-temperature epoxy formulations (coatings, adhesives, sealants, castings, etc.), yet the curing reaction and properties of resultant epoxy systems still remain less fundamentally understood. Herein we systematically investigate our newly-developed acrylonitrile-modified multifunctional polyamine curing agent for bisphenol A epoxy resin (DGEBA): an acrylonitrile-capped poly(propyleneimine) dendrimer (PAN4). The impact of the molecular structure of PAN4 and a controlled poly(propyleneimine) dendrimer (1.0GPPI) on the curing reactivity, reaction mechanisms, thermal stability, viscoelastic response and mechanical properties of the epoxy systems are highlighted. Differential scanning calorimetry (DSC) confirms DGEBA/PAN4 shows markedly lower reactivity and reaction exotherm than DGEBA/1.0GPPI, and the model-free isoconversional kinetic analysis reveals that DGEBA/PAN4 has the generally lower reaction activation energy. To be quantitative, the progress of the isothermal cure is predicted from the dynamic cure by using the Vyazovkin equation. The isothermal kinetic prediction shows that DGEBA/PAN4 requires about 10 times longer time to achieve the same conversion than DGEBA/1.0GPPI, which agrees with the experimentally observed much longer gel time of DGEBA/PAN4. Subsequently, dynamic mechanical analysis shows that PAN4 results in the cured epoxy network with the lower β - and glass-relaxation temperatures, crosslink density, relaxation activation energy, enthalpy, entropy, but the higher damping near room temperature than 1.0GPPI. Finally, thermogravimetric analysis (TGA) demonstrates cured DGEBA/PAN4 is thermally stable up to 200 °C, and mechanical property tests substantiate that PAN4 endows the cured epoxy with much higher impact and adhesion strengths than 1.0GPPI. Our data can provide a deeper insight into acrylonitrile-modified aliphatic amine curing agents from the two good model compounds (PAN4 and 1.0GPPI).

Aminopropyl groups on the surface of aminopropylated silica gel were lengthened by grafting of additional propyleneimine units and applied to immobilize singlet oxygen sensitizers of cationic phthalocyanine series. The absorption and fluorescence spectra, generation of singlet oxygen and photobactericidal activity were studied for aqueous suspensions of these new heterogeneous systems. The effect of spacer length upon absorption and emission spectra as well as on efficacy of singlet oxygen generation by tethered phthalocyanines was not observed. However, the photobactericidal function of the supported phthalocyanines was markedly increased along with length of spacer.

A sensitive and reagentless electrochemical aptatoxisensor was developed on cobalt (II) salicylaldiimine metallodendrimer (SDD–Co(II)) doped with electro-synthesized silver nanoparticles (AgNPs) for microcystin-LR (L, l-leucine; R, l-arginine), or MC-LR, detection in the nanomolar range. The GCE|SDD–Co(II)|AgNPs aptatoxisensor was fabricated with 5’ thiolated aptamer through self-assembly on the modified surface of the glassy carbon electrode (GCE) and the electronic response was measured using cyclic voltammetry (CV). Specific binding of MC-LR with the aptamer on GCE|SDD–Co(II)|AgNPs aptatoxisensor caused the formation of a complex that resulted in steric hindrance and electrostatic repulsion culminating in variation of the corresponding peak current of the electrochemical probe. The aptatoxisensor showed a linear response for MC-LR between 0.1 and 1.1 µg·L−1 and the calculated limit of detection (LOD) was 0.04 µg·L−1. In the detection of MC-LR in water samples, the aptatoxisensor proved to be highly sensitive and stable, performed well in the presence of interfering analog and was comparable to the conventional analytical techniques. The results demonstrate that the constructed MC-LR aptatoxisensor is a suitable device for routine quantification of MC-LR in freshwater and environmental samples.

Dendrimers are hyperbranched, monodispersed macromolecules with multivalent functional end groups. Dendrimers have been explored as carrier for many drugs like anticancer, antiviral, antimalarial, antiprotozoal, anti tubercular drugs. Although a number of different types of dendrimers containing different core molecules, branching monomers and surface functional groups have been designed till date for drug delivery applications, yet the poly(propyleneimine) (PPI) and poly(amidoamine) (PAMAM) dendrimers have been the most explored dendrimers in this regard. In this review, we have summarized a comparative data on PPI and PAMAM dendrimers particularly relevant to their properties, synthesis, toxicity, biomedical applications and drug delivery attributes.

A well balanced amphiphilic poly(propyleneimine) dendrimer (APPI-G2) was synthesized and used as an effective template for the stabilization of gold nanoparticle (AuNPs). The APPI-G2 served as a stabilizing as well as reducing agent for AuNPs. The APPI-G2 stabilized AuNPs (APPI-G2-AuNPs) were characterized by UV-visible spectroscopy (UV-Vis) and transmission electron microscopy (TEM). The size of the AuNPs was in the range of 7 to 16 nm and their growth during the synthesis showed splitting of surface plasmon resonance band. Further, APPI-G2-AuNPs were also prepared by varying the APPI-G2 concentration keeping [Au 3+ ] constant and vice-versa to examine the stabilization efficiency of APPI-G2. The APPI-G2 stabilized more than 5 × 10 −6 M of AuNPs. The prepared catalysts were found to exhibit enhanced catalytic activity towards the reduction of nitrobenzene in aqueous medium and the reaction rate constant was estimated to be 26.31 × 10 −3 s −1 .

The thermodynamic characteristics of ultimately dilute solutions of n-alkanes and n-alkanols in columnar and isotropic poly(propyleneimine) dendrimer phases of three generations (G1-G3) were studied by reversed-phase gas chromatography. The influence of the structure of dendrimers and the chemical nature and the size of nonmesogen molecules on their ability to be dissolved in liquid crystalline phases is discussed. It was found that the compatibility of low-molecular-weight compounds with anisotropic phases increased as the number of dendrimer generation grew.