Propylene Imine Dendrimers Research Articles

New Water-Soluble Poly(propylene imine) Dendrimer Modified with 4-Sulfo-1,8-naphthalimide Units: Sensing Properties and Logic Gates Mimicking.

A new water-soluble poly(propylene imine) dendrimer (PPI) modified with 4-sulfo-1,8-naphthalimid units (SNID) and its related structure monomer analog (SNIM) has been prepared by a simple synthesis. The aqueous solution of the monomer exhibited aggregation-induced emission (AIE) at 395 nm, while the dendrimer emitted at 470 nm due to an excimer formation beside the AIE at 395 nm. Fluorescence emission of the aqueous solution of either SNIM or SNID was significantly affected by traces of different miscible organic solvents, and the limits of detection were found to be less than 0.05% (v/v). Moreover, SNID exhibited the function to execute molecular size-based logic gates where it mimics XNOR and INHIBIT logic gates using water and ethanol as inputs and the AIE/excimer emissions as outputs. Hence, the concomitant execution of both XNOR and INHIBIT enables SNID to mimic digital comparators.

PARAMETRIC OPTIMIZATION OF DYES ABSORPTION USING POLYPROPYLENE IMINE DENDRIMER FROM TEXTILE WASTEWATER

Recently, Dendrimers are famous for monodispersed, highly branched, three dimensional, macromolecular nanoscopic architecture with several groups of the reactive end. Dendrimers work as dye removal agents from the two systems liquid-solid or liquid-liquid. This study tackles the textile dyes removal from aqueous solutions by Reactive Black 5 (RB5), Acid Blue 7 (AB7), Reactive Red 198 (RR198), Acid Green 25 (AG25), poly (propylene imine) dendrimer (PPI). and have been utilized as model dyes. Operational parameters influence the removal of dye like the concentration of dye, the concentration of dendrimer, pH, time, and temperature were investigated. Findings revealed that the efficiency of dye removal was maximized by increasing both concentrations of dye and dendrimers. Furthermore, results showed that the adsorption of dyes was supported by acidic pH through dendrimer. Besides, tests showed that maximum dyes removal were achieved at time 16h and temperature around 60 °C. As the data revealed, it can be concluded that dendrimers are adsorbent which is environmentally friendly with somehow big adsorption ability of could be an advisable substitute for dyes elimination from coloured textile wastewater.

Synthesis of structurally enhanced magnetite cored poly(propyleneimine) dendrimer nanohybrid material and evaluation of its functionality in sustainable catalysis of condensation reactions

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.

ACUTE TOXICOLOGICAL INVESTIGATION OF POLYETHYLENE GLYCOL DERIVATIZED FOURTH AND FIFTH GENERATION POLY (PROPYLENEIMINE) DENDRIMERS

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.

An Electrochemical Cholesterol Biosensor Based on A CdTe/CdSe/ZnSe Quantum Dots-Poly (Propylene Imine) Dendrimer Nanocomposite Immobilisation Layer.

We report the preparation of poly (propylene imine) dendrimer (PPI) and CdTe/CdSe/ZnSe quantum dots (QDs) as a suitable platform for the development of an enzyme-based electrochemical cholesterol biosensor with enhanced analytical performance. The mercaptopropionic acid (MPA)-capped CdTe/CdSe/ZnSe QDs was synthesized in an aqueous phase and characterized using photoluminescence (PL) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), X-ray power diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy. The absorption and emission maxima of the QDs red shifted as the reaction time and shell growth increased, indicating the formation of CdTe/CdSe/ZnSe QDs. PPI was electrodeposited on a glassy carbon electrode followed by the deposition (by deep coating) attachment of the QDs onto the PPI dendrimer modified electrode using 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC), and N-hydroxysuccinimide (NHS) as a coupling agent. The biosensor was prepared by incubating the PPI/QDs modified electrode into a solution of cholesterol oxidase (ChOx) for 6 h. The modified electrodes were characterized by voltammetry and impedance spectroscopy. Since efficient electron transfer process between the enzyme cholesterol oxidase (ChOx) and the PPI/QDs-modified electrode was achieved, the cholesterol biosensor (GCE/PPI/QDs/ChOx) was able to detect cholesterol in the range 0.1–10 mM with a detection limit (LOD) of 0.075 mM and sensitivity of 111.16 μA mM−1 cm−2. The biosensor was stable for over a month and had greater selectivity towards the cholesterol molecule.

Dendrimer-Stabilized Ru Nanoparticles Immobilized in Organo-Silica Materials for Hydrogenation of Phenols

New hybrid catalysts based on Ru nanoparticles, encapsulated into poly(propylene imine dendrimers), immobilized into silica pores, were synthesized and examined for the hydrogenation of alkyl-substituted phenols. The corresponding alkyl-substituted cyclohexanols were presented as the major reaction products, while incomplete hydrogenation products appeared to be minor. A competition between the sterical factors of dendrimer-containing carriers and the electronic factors of substrate substituents influenced the hydrogenation rate of the alkyl-substituted phenols. The carrier structure was found to have a significant influence on both the physical and chemical properties of the catalysts and their hydrogenation activity. The synthesized hybrid catalysts appeared to be stable after recycling and could be re-used several times without significant loss of activity.

Introduction of amine terminated dendritic structure to graphene oxide using Poly(propylene Imine) dendrimer to evaluate its organic contaminant removal

Abstract In this study, graphene oxide (GO) as one of the newest member of carbon materials with high specific surface area was modified using poly(propylene imine) dendrimer (PPI) with a regular and highly branched structure containing eight amine terminated functional groups. The transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS) and zeta potential analyzer were employed to characterize the new adsorbent. In order to demonstrate the adsorption capacity of this super adsorbent (GO-PPI), the removal of two anionic dyes (C.I. Acid Red 14 and C.I. Acid Blue 92) using GO-PPI was compared to graphite (G) and GO. Adsorbent dosage, pH, initial dye concentration and temperature were investigated as the parameters affecting the adsorption performance. Isotherm, kinetic and thermodynamic of dye removal was also studied. Langmuir isotherm and pseudo-second-order kinetic models well described the dye removal mechanism and adsorption rate, respectively. The spontaneous and exothermic nature of the adsorption process was demonstrated by negative values of Gibbs free energy (ΔG) and enthalpy (ΔH). The maximum adsorption capacity of G and GO was 169.49 and 9.302 mg/g, while the adsorption capacity of GO-PPI improved significantly to reach 434.78 mg/g.

Surface engineered dendrimers as antiangiogenic agent and carrier for anticancer drug: dual attack on cancer.

The present research work describes the formulation of arginine conjugated 3.0G Poly(propylene) imine (PPI) dendrimers, mimicking the surface structure of an endogenous angiogenesis-inhibitor endostatin; for tumor specific delivery of a model anticancer drug, doxorubicin hydrochloride (Dox). Synthesis of PPI dendrimers and conjugation of arginine to surface groups was confirmed by FTIR, NMR, TEM and mass spectrometry. Drug was loaded by equilibrium dialysis method and developed formulation was evaluated for entrapment efficiency, hemolytic toxicity, in vitro drug release, stability, anti-angiogenic activity via in vivo chick embryo chorioallantoic membrane (CAM) assay, and anticancer activity and cell uptake using MCF-7 cancer cell lines. The system exhibited the initial rapid release followed by sustained release of Dox with significant antiangiogenic activity in the CAM assay. Further, the arginine conjugated dendrimers was found to inhibit growth of cancer cells in ex vivo studies with MCF-7 cell lines. Cell uptake studies suggested that in comparison to free drug the formulation was preferably taken up by the tumor cells. Thus the two pronged attack on cancerous tissue i.e., inhibition of angiogenesis and killing of cancer cells by anticancer drug, might prove to be a promising approach in the treatment of fatal disease, cancer.

Dendrimers/TiO2 nanoparticles layer-by-layer films as extended gate FET for pH detection

The layer-by-layer (LbL) technique combined with field-effect transistor (FET) based sensors has enabled the production of pH-sensitive platforms with potential application in biosensors. A variation of the FET architecture, so called separative extended gate FET (SEGFET) devices, are promise as an alternative to conventional ion sensitive FET (ISFET). SEGFET configuration exhibits the advantage of combining the field-effect concept with organic and inorganic materials directly adsorbed on the extended gate, allowing the test of new pH-sensitive materials in a simple and low cost way. In this communication, poly(propylene imine) dendrimer (PPI) and TiO2 nanoparticles (TiO2-np) were assembled onto gold-covered substrates via layer-by-layer technique to produce a low cost SEGFET pH sensor. The sensor presented good pH sensitivity, ca. 57mVpH−1, showing that our strategy has potential advantages to fabricate low cost pH-sensing membranes.

Characteristics of complexes between poly(propylene imine) dendrimers and nucleotides

The aim of our work was to study the G4 and the G5 generations of cationic poly(propylene imine) dendrimers (PPI) as potential anticancer drug carriers. PPI dendrimers with 50% of primary amino surface groups modified with maltose were applied (PPI-m). Adenosine 5′-phosphates (AMP, ADP and ATP)—structural analogues of anticancer drug (fludarabine) were chosen as model molecules. Using Fast Performance Liquid Chromatography (FPLC) it has been shown that nucleotide analogues form stable complexes with the dendrimers. The number of nucleotides complexed with PPI-m G4 and G5 dendrimers depends on (1) nucleotide form, (2) time, (3) concentration of NaCl in the solution and (4) pH of solution. Obtained results are promising enough to further study PPI-m dendrimers as nanosized carrier systems for anticancer drugs.

Complex Dendrimer–Lyotropic Liquid Crystalline Systems: Structural Behavior and Interactions

The incorporation of dendrimer into three lyotropic liquid crystalline (LLCs) mesophases is demonstrated for the first time. A second generation (G2) of poly(propylene imine) dendrimer (PPI) was solubilized into lamellar, diamond reverse cubic, and reverse hexagonal LLCs composed of glycerol monooleate (GMO), and water (and D-α-tocopherol in the H(II) system). The combination of PPI with LLCs may provide an advantageous drug delivery system. Cross-polarized light microscope, small-angle X-ray scattering (SAXS), and attenuated total reflectance Fourier transform infrared (ATR-FTIR) were utilized to study the structural behavior of the mesophases, the localization of PPI within the system, and the interactions between the guest molecule and the system's components. It was revealed that PPI-G2 functioned as a "water pump", competing with the lipid headgroups for water binding. As a result, L(α)→H(II) and Q(224)→H(II) structural shifts were detected (at 10 wt % PPI-G2 content), probably caused by the dehydration of monoolein headgroups and subsequent increase of the lipid's critical packing parameter (CPP). In the case of H(II), as a result of the balance between the dehydration of the monoolein headgroups and the significant presence of PPI within the interfacial region, increasing the quantity of hydrogen bonds, no structural transitions occurred. ATR-FTIR analysis demonstrated a downward shift of the H-O-H (water), as a result of PPI-G2 embedment, suggesting an increase in the mean water-water H-bond angle resulting from binding PPI-G2 to the water network. Additionally, the GMO hydroxyl groups at β- and γ-C-OH positions revealed a partial interaction of hydrogen bonds with N-H functional groups of the protonated PPI-G2. Other GMO interfacial functional groups were shown to interact with the PPI-G2, in parallel with the GMO dehydration phenomenon. In the future, these outcomes can be used to design advanced drug delivery systems, allowing administration of dendrimers as a therapeutic agent from LLCs.

Dye Removal from Colored Textile Wastewater by Poly(propylene imine) Dendrimer: Operational Parameters and Isotherm Studies

AbstractThis paper deals with the removal of textile dyes from aqueous solutions by poly(propylene imine) dendrimer (PPI). Direct red 80 (DR80), Acid Green 25 (AG25), Acid Blue 7 (AB7), and Direct Red 23 (DR23) were used as model dyes. The effects of operational parameters on dye removal such as dendrimer concentration, dye concentration, salt (inorganic anions), and pH have been studied at 25°C. The Langmuir and Freundlich isotherm models were investigated. In addition, dye desorption of dendrimer was studied. The results indicated that acidic pH supported the adsorption of dyes by dendrimer. Furthermore studies of dye concentration and salt effects exhibited that dye removal percentage by dendrimer was decreased. It was found that the isotherm data of DR80, AG25, and DR23 followed Langmuir isotherm and isotherm data of AB7 followed Freundlich isotherm models. Desorption tests showed that maximum dye releasing of 76.5% for DR80, 84.5% for AG25, 87% for AB7, and 93% for DR23 were achieved in aqueous solution at pH 12. Based on the data of present study, one could conclude that the dendrimer being an environmentally friendly adsorbent with relatively large adsorption capacity might be a suitable alternative for elimination of dyes from colored textile wastewater.

Learning about novel amine-adduct curing agents for epoxy resins: Butyl-glycidylether-modified poly(propyleneimine) dendrimers

Novel butyl-glycidylether-modified poly(propyleneimine) dendrimers (PPIs) are prepared by reacting butyl glycidylether with PPI, which turn out to be able to cure bisphenol-A epoxy resin to an acceptable reaction extent. The nonisothermal reactions, dynamic mechanical properties and thermal stabilities of their cured epoxy resin are comparatively investigated with DSC, DMA and TGA, respectively. The model-fitting kinetic study demonstrates that Šesták–Berggren model can generally well simulate the reaction rates, and the isoconversional kinetic analysis with the Vyazovkin method indicates the curing agents, particularly their setric hindrance and the number of the –OH groups attached, greatly affect reaction kinetic schemes. Increasing the number of the BGE substituents attached to PPIs decreases the reactivity, glass- and beta-relaxation temperatures and thermal stability of the resulting epoxy systems, yet the intensity and width of the glass relaxation increase. This work offers a unique way of preparing modified-aliphatic-polyamine curing agents, and provides an opportunity to better learn about the amine-adduct curing agents which are widely used in room-temperature-cure epoxy coatings and adhesives from these good model compounds.

Solubilization of a Dendrimer into a Microemulsion

The present work investigates, for the first time, a system comprising a dendrimer incorporated into the water core of water-in-oil (W/O) microemulsion (ME). A second generation (G-2) poly(propyleneimine) dendrimer (PPI) was solubilized into W/O ME composed of AOT (sodium bis(2-ethylhexyl)sulfosuccinate), heptane, and water. Such a model system possessing the benefits of both dendrimers and ME, can potentially offer superior control of drug administration. The localization of PPI within the system, its specific interactions with the components of the carrier, and its effect on the ME structure was explored by SAXS, DSC, ATR-FTIR, and electrical conductivity measurements. Considerable water binding by PPI, accompanied by partial dehydration of AOT polar heads, was detected by ATR-FTIR and DSC analysis, suggesting that PPI acted as a "water pump". In addition, SAXS measurements showed periodicity increase and disordering of the droplets. Hence, localization of PPI within the core and interfacial regions of the droplets was assumed. Direct electrostatic interactions between PPI and the sulfonate group were not noticed, since the dendrimer molecules were mostly not protonated in the current basic environment at pH 12. However, slight hydrogen bonding between PPI and the S=O groups allowed the dendrimer to behave as a "spacer" between sodium and sulfonate ions. This affected the electrical conductivity behavior of the system, revealing that PPI favored the percolation process. Most likely, PPI decreased the rigidity of the interfacial layer, facilitating the diffusion of sodium ions through the channels. The characterized model system can be advantageously utilized to design specific delivery vehicles, allowing administration of dendrimers as a therapeutic agent from host MEs.

Single and Binary System Dye Removal from Colored Textile Wastewater by a Dendrimer as a Polymeric Nanoarchitecture: Equilibrium and Kinetics

This paper deals with the removal of textile dyes from aqueous solutions by a poly(propylene imine) dendrimer (PPI) as a polymeric nanoarchitecture in single and binary (mixture of dyes) systems. Direct Blue 78 (DB78) and Acid Black 26 (AB26) were used as model dyes. The effects of operational parameters such as dendrimer concentration, contact time, dye concentration, inorganic anions (salts), and pH have been studied on dye removal. Adsorption isotherms (Langmuir, Freundlich, and Tempkin models), adsorption kinetics (pseudofirst order, pseudosecond order, and intraparticle diffusion), and dye desorption were studied in single and binary dye systems. It was found that the isotherm data of DB78 and AB26 in single and binary systems of dyes followed the Langmuir isotherm. Adsorption kinetics of dyes in single and binary dye systems were found to conform to a pseudosecond order model. Desorption tests showed that the maximum dye releases of 93 % for DB78 and 86 % for AB26 in a single system and 90 % for DB7...

Immobilization of Poly(propylene imine) Dendrimer/Nickel Phtalocyanine as Nanostructured Multilayer Films To Be Used as Gate Membranes for SEGFET pH Sensors

We describe the assembly of layer-by-layer films based on the poly(propylene imine) dendrimer (PPID) generation 3 and nickel tetrasulfonated phthalocyanine (NiTsPc) for application as chemically sensitive membranes in separative extended-gate field effect transistor (SEGFET) pH sensors. PPID/NiTsPc films were adsorbed on quartz, glass, indium tin oxide, or gold (Au)-covered glass substrates. Multilayer formation was monitored via UV-vis absorption upon following the increment in the Q-band intensity (615 nm) of NiTsPc. The nanostructured membranes were very stable in a pH range of 4-10 and displayed a good sensitivity toward H + , ca. 30 mV/pH for PPID/NiTsPc films deposited on Au-covered substrates. For films deposited on ITO, the sensitivity was ca. 52.4 mV/pH, close to the expected theoretical value for ion-sensitive membranes. The use of chemically stable PPID/NiTsPc films as gate membranes in SEGFETs, as introduced here, may represent an alternative for the fabrication of nanostructured, porous platforms for enzyme immobilization to be used in enzymatic biosensors.

An Electrochemical DNA Biosensor Developed on a Nanocomposite Platform of Gold and Poly(propyleneimine) Dendrimer.

An electrochemical DNA nanobiosensor was prepared by immobilization of a 20mer thiolated probe DNA on electro-deposited generation 4 (G4) poly(propyleneimine) dendrimer (PPI) doped with gold nanoparticles (AuNP) as platform, on a glassy carbon electrode (GCE). Field emission scanning electron microscopy results confirmed the co-deposition of PPI (which was linked to the carbon electrode surface by C-N covalent bonds) and AuNP ca 60 nm. Voltammetric interrogations showed that the platform (GCE/PPI-AuNP) was conducting and exhibited reversible electrochemistry (E°′ = 235 mV) in pH 7.2 phosphate buffer saline solution (PBS) due to the PPI component. The redox chemistry of PPI was pH dependent and involves a two electron, one proton process, as interpreted from a 28 mV/pH value obtained from pH studies. The charge transfer resistance (Rct) from the electrochemical impedance spectroscopy (EIS) profiles of GCE/PPI-AuNP monitored with ferro/ferricyanide (Fe(CN)63-/4-) redox probe, decreased by 81% compared to bare GCE. The conductivity (in PBS) and reduced Rct (in Fe(CN)63-/4-) values confirmed PPI-AuNP as a suitable electron transfer mediator platform for voltammetric and impedimetric DNA biosensor. The DNA probe was effectively wired onto the GCE/PPI-AuNP via Au-S linkage and electrostatic interactions. The nanobiosensor responses to target DNA which gave a dynamic linear range of 0.01 - 5 nM in PBS was based on the changes in Rct values using Fe(CN)63-/4- redox probe.

Poly(propyleneimine) dendrimer and dendrosome mediated genetic immunization against hepatitis B

The purpose of the present research work is to explore the potential of dendrosomes in genetic immunization against hepatitis B. Plasmid DNA encoding pRc/CMV-HBs[S] (5.6 kb), encoding the small region of the hepatitis B surface antigen, was complexed with 5th generation poly(propyleneimine) dendrimer (PPI) in different ratios. Transfection of CHO cells revealed that a ratio of 1:50 for pDNA:PPI was optimum for transfection. Results of cytotoxicity studies showed that the toxicity of PPI–DNA complex was significantly ( p < 0.05) higher for PPI 75 and PPI 100 as compared to the other PPI–DNA complexes. PPI 50 was employed for preparation of dendrosomes by reverse phase evaporation method. The dendrosomal formulation DF3 was found to possess optimum vesicle size, zeta potential and entrapment efficiency. In vitro production of HBsAg in CHO cells showed that DF3 possess maximum transfection efficiency. In vivo immunization studies were carried out by giving a single intramuscular injection of 10 μg of plasmid DNA (pDNA) or its dendrimeric or dendrosomal formulation to female Balb/c mice, followed by estimation of total IgG, IgG 1, IgG 2a, IgG 2b, biweekly. DF3 was found to elicit maximum immune response in terms of total IgG and its subclasses under study as compared to PPI 50 and pDNA at all time points. Animals immunized with DF3 developed very high cytokine level. Higher level of IFN-γ suggests that the immune response was strictly Th1 mediated. Our observations clearly prove the superiority of dendrosomes over PPI–DNA complex and pDNA for genetic immunization against hepatitis B.

Targeting of efavirenz loaded tuftsin conjugated poly(propyleneimine) dendrimers to HIV infected macrophages in vitro

HIV infected macrophages are considered as reservoirs for spreading the virus in AIDS patients. Tuftsin not only binds specifically to the mononuclear phagocytic cells but also enhances their natural killer activity. The purpose of this study is to explore the targeting potential and anti-HIV activity of efavirenz (EFV) loaded, tuftsin conjugated 5th generation poly(propyleneimine) dendrimers (TuPPI) in vitro. Tuftsin was chemically conjugated to 5th generation poly(propyleneimine) dendrimers (PPI). The entrapment efficiency of PPI and TuPPI were found to be 37.43 ± 0.3% and 49.31 ± 0.33%, respectively. TuPPI was found to slow down and prolong the in vitro release of EFV upto 144 h against PPI, which releases the drug completely within 24 h. TuPPI possessed negligible cytotoxicity as compared to that of PPI. The cellular uptake of TuPPI was found to be 34.5 times higher than that of the free drug in first 1 h and was significantly higher in HIV infected macrophages than that of uninfected cells. TuPPI was found to reduce the viral load by 99% at a concentration of 0.625 ng/ml, which is due to the enhanced cellular uptake, reduced toxicity and the inherent anti-HIV activity of TuPPI.

Toxicological investigation of surface engineered fifth generation poly (propyleneimine) dendrimers in vivo

Dendrimers are three dimensional polymers, nanoscopic in size, most widely explored in the field of drug delivery in recent times. In order to establish these polymers as controlled and targeted drug delivery systems, they should be non-toxic, biocompatible and biodegradable. The purpose of the present study is to investigate the toxicological profile of fifth generation poly (propyleneimine) dendrimers (PPI) and some of its surface engineered derivatives. Functionalized PPI dendrimers (TPPI, MPPI and TuPPI) were synthesized to mask the primary amino groups responsible for the positive charge and associated toxicity. Each polymer is 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, and blood as well as tissue samples were collected after 24 h and 15 days. Decrease in RBC count and hemoglobin content after 24 h, in case of animals administered with PPI suggests hemolytic activity of PPI. Significant increase in SGOT, SGPT and LDH indicates that PPI causes severe damage to the membranes of the various tissues of the body, especially that of the liver leading to the leakage of these marker enzymes in blood. Sections of liver of animals administered with PPI showed signs of tissue degeneration after 24 h. No signs of toxicity were observed in case of animals administered with functionalized PPI. Neither PPI nor its surface engineered derivatives showed any signs of immunogenicity. It can be concluded that functionalization of dendrimers leads to drastic reduction of toxicity and increases biocompatibility.