Polyamide-amine (PAMAM) dendrimer, a new hyperbranched macromolecular polymer, is considered an "artificial protein" by many scholars on account of its excellent chemical and biological characteristics. PAMAM has internal cavities and a large number of reactive terminal groups. These structures allow the polymer to be used as a bionic macromoleculethat could simulate the biomimetic mineralization of the natural organic matrix on the surface of tooth tissue. Specifically, PAMAM can beused as an organic template to regulate mineral nucleation and crystal growth; thus, the polymerisa more ideal dental restoration material than traditional allogenic materials. This article reviews research progress on thePAMAM-induced biomimetic mineralization of hard tooth tissues.
Amines ; Biomimetics ; Dendrimers ; Humans ; Nylons ; Tooth Remineralization

The objective of this work is to evaluate the effect of polyamidoamine (PAMAM) dendrimers on electroosmotic flow (EOF) through skin. The effect of size and concentration of dendrimer was studied, using generation 1, 4 and 7 dendrimer (G1, G4 and G7, respectively). As a marker molecule for the direction and magnitude of EOF, a neutral molecule, acetoaminophen (AAP) was used. The visualization of dendrimer permeation into the current conducting pore (CCP) of skin was made using G4–fluorescein isothiocyanate (FITC) conjugate and confocal microscopy. Without dendrimer, anodal flux of AAP was much higher than cathodal or passive flux. When G1 dendrimer was added, anodal flux decreased, presumably due to the decrease in EOF by the association of G1 dendrimer with net negative charge in CCP. As the generation increased, larger decrease in anodal flux was observed, and the direction of EOF was reversed. Small amount of methanol used for the preparation of dendrimer solution also contributed to the decrease in anodal flux of AAP. Cross-sectional view perpendicular to the skin surface by confocal laser scanning microscope (CLSM) study showed that G4 dendrimer-FITC conjugate (G4-FITC) can penetrate into the viable epidermis and dermis under anodal current. The permeation route seemed to be localized on hair follicle region. These results suggest that PAMAM dendrimers can permeate into CCP and change the magnitude and direction of EOF. Overall, we obtained a better understanding on the mechanistic insights into the electroosmosis phenomena and its role on flux during iontophoresis.
Acetaminophen ; Dendrimers* ; Dermis ; Electroosmosis* ; Epidermis ; Fluorescein-5-isothiocyanate ; Hair Follicle ; Iontophoresis ; Methanol ; Microscopy, Confocal ; Skin*

A novel targeting drug carrier (FA-BO-PAMAM) based on the PAMAM G5 dendrimer modified with borneol (BO) and folic acid (FA) molecules on the periphery and doxorubicin (DOX) loaded in the interior was designed and prepared to achieve the purposes of enhancing the blood-brain barrier (BBB) transportation and improving the drug accumulation in the glioma cells. 1H NMR was used to confirm the synthesis of FA-BO-PAMAM; its morphology and mean size were analyzed by dynamic light scattering (DLS) and transmission electron microscope (TEM). Based on the HBMEC and C6 cells, cytotoxicity assay, transport across the BBB, cellular uptake and anti-tumor activity in vitro were investigated to evaluate the properties of nanocarriers in vitro. The results showed that the nanocarrier of FA-BO-PAMAM was successfully synthesized, which was spherical in morphology with the average size of (22.28 ± 0.42) nm, and zeta potential of (7.6 ± 0.89) mV. Cytotoxicity and transport across the BBB assay showed that BO-modified conjugates decreased the cytotoxicity of PAMAM against both HBMEC and C6 cells and exhibited higher BBB transportation ability than BO-unmodified conjugates; moreover, modification with FA increased the total uptake of DOX by C6 cells and enhanced the cytotoxicity of DOX-polymer against C6 cells. Therefore, FA-BO-PAMAM is a promising nanodrug delivery system in employing PAMAM as a drug carrier and treatment for brain glioma.
Biological Transport ; Blood-Brain Barrier ; Bornanes ; chemistry ; Cell Line, Tumor ; Dendrimers ; Doxorubicin ; pharmacology ; Drug Carriers ; chemistry ; Drug Delivery Systems ; Folic Acid ; chemistry ; Glioma ; Humans

Pluronic modified polyamidoamine (PAMAM) conjugate (PF127-PAMAM) was prepared and the inhibiting effect of MDR against MCF-7/ADR was investigated with doxorubicin (DOX) as model drug. 1H NMR and FTIR spectra showed that the conjugate was synthesized successfully. Element analysis accurately measured that 27.63% amino of per PAMAM was modified by pluronic (PAMAM : PF127, 1 : 35.37 mole ratio). PF127-PAMAM showed an increased size and a reduced zeta potential compared to PAMAM. PF127-PAMAM had lower hemolytic toxicity and cytotoxicity due to the reduced zeta potential and the protection of PF127. Each PF127-PAMAM molecular could load 19.58 DOX molecules, and the complex exhibited sustained and pH-sensitive release behavior. PF127-PAMAM/DOX exhibited weaker cytotoxicity than free DOX in MCF-7 cells; while the complex showed much stronger reverse effect of drug resistance in MCF-7/ADR cells, and resistance reversion index (RRI) was as high as 33.15.
Dendrimers ; pharmacology ; Doxorubicin ; pharmacology ; Humans ; MCF-7 Cells ; drug effects ; Poloxamer ; pharmacology

Polyamidoamine (PAMAM) dendrimers is synthesized by the American scientist, Tomalia, in 1985 and is now used widely in many fields such as gene carriers, photoelectric sensor, wastewater treatment, drug carriers and catalyst. The present paper mainly reviews the structure and methods of synthesis, celluar cytotoxicity, achievements of gene and drug carriers research, advancement and prospect of PAMAM as a carrier in glioma therapy. Besides, it also involves an outline for the future research of the radiotherapy for glioma.
Biocompatible Materials ; chemical synthesis ; chemistry ; Dendrimers ; chemical synthesis ; chemistry ; Drug Carriers ; Genetic Vectors

OBJECTIVETo explore if folic acid/polyamide-amine (FA/PAMAM) enhances the therapeutic effect of miR-7gene therapy for glioma in vivo.

METHODSThe miR-7 gene was transfected into U251 glioma cells by FA/PAMAM. The efficiency of gene transfection was assessed by fluorescence microscopy. The miR-7 level was detect by quantitative RT-PCR. Intracranial glioma models were established in thymectomized mice, and FA/PAMAM nanoparticles were transplanted into the tumors in situ 3 days later. The animal survival was recorded and the gross tumor volume and degree of edema were observed by MRI. Apoptosis in the glioma cells and expression of proliferating cell nuclear antigen (PCNA), matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) were assessed by immunohistochemistry, and EGFR and AKT-2 protein expression was detected by Western blot assay.

RESULTSCompared with the liposomes, the FA/PAMAM nanoparticles were more efficient to transfer miR-7 gene into U251 glioma cells, MRI showed that the tumor growth was much slower in the FA/PAMAM/miR-7 group, and the animal survival time was longer. The apoptosis rate was (5.3 ± 0.9)% in the control group, (11.4 ± 2.4)% in the liposome/miR-7 group, and (17.7 ± 3.7)% in the FA/PAMAM/miR-7 group. The immunohistochemical assay showed that the levels of PCNA, MMP-2 and MMP-9 protein in the FA/PAMAM/miR-7 group were (34.6 ± 5.4)%, (24.5 ± 4.1)%, (25.4 ± 5.1)%, respectively, significantly lower than those in the liposome/miR-7 group (49.3 ± 5.9)%, (31.7 ± 7.1)% and (39.4 ± 6.4)%, respectively, and those in the control group (57.3 ± 7.4)%, (45.4 ± 6.9)% and (55.1 ± 7.3)%, respectively (all P < 0.05). The expressions of EGFR and AKT-2 proteins were 1.09 ± 0.12 and 0.62 ± 0.10 in the control group, 0.63 ± 0.11 and 0.43 ± 0.07 in the liposome/miR-7 group, and significantly deceased (0.47 ± 0.09 and 0.31 ± 0.04, respectively) in the FA/PAMAM/miR-7 group (all P < 0.05).

CONCLUSIONCompared with the liposomes, FA/PAMAM can transfect miR-7 into glioma cells with a higher efficiency in vivo, makes a longer time of the drug action, and shows a certain inhibitory effect on the growth of glioma, therefore, might become a new drug targeting agent in gene therapy forglioma.

Animals ; Apoptosis ; Brain Neoplasms ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; Dendrimers ; chemistry ; Folic Acid ; chemistry ; Genetic Therapy ; methods ; Glioma ; genetics ; metabolism ; pathology ; Humans ; Male ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Mice ; Mice, Nude ; MicroRNAs ; genetics ; metabolism ; Nanoparticles ; Neoplasm Transplantation ; Proliferating Cell Nuclear Antigen ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Receptor, Epidermal Growth Factor ; metabolism ; Thymectomy ; Transfection

Targeting drug delivery system (TDDS) is one of the most concerned research fields in cancer treatment because it can bind selectively and react with the target diseased sites at the cellular or sub-cellular level, making distribution and release of drugs in a controlled manner, thus enhance therapeutic effects and reduce toxic and side-effects on normal cells. Polyamidoamine dendrimer (PAMAMD) is a kind of newly developed polymer in nanometer degree. Hyper-branched, monodispersity, three-dimensional structure and host-guest entrapment ability make it used as drug carrier, gene delivery system and imaging agent. Various targeting ligands, which have high affinity to specific organs, tissues or cells in human body, can be linked to surface functional groups of PAMAMD. And drugs and theoretical gene are carried by encapsulation or chemical conjugation. Finally, PAMAMD targeting drug delivery system can carry drugs and theoretical gene to diseased sites and then release them for targeted therapy. The PAMAMD-based conjugates have small size, ligh permeability and retention effect (EPR), low toxicity and so on. The research progress of PAMAMD modified by different ligands in targeting drug delivery system is reviewed, and research direction of the PAMAMD targeting delivery system in the future is also suggested.
Amino Acids ; administration & dosage ; chemistry ; Animals ; Antibodies, Monoclonal ; administration & dosage ; chemistry ; Antineoplastic Agents ; administration & dosage ; therapeutic use ; Biotin ; administration & dosage ; chemistry ; Dendrimers ; administration & dosage ; chemistry ; Drug Carriers ; administration & dosage ; chemistry ; Drug Delivery Systems ; Folic Acid ; administration & dosage ; chemistry ; Gene Transfer Techniques ; Humans ; Ligands ; Neoplasms ; drug therapy ; Polyamines ; administration & dosage ; chemistry ; pharmacokinetics ; Polyethylene Glycols ; administration & dosage ; chemistry ; Transferrin ; administration & dosage ; chemistry

Polyamidoamine-polyethylene glycol (PAMAM-PEG) copolymers were synthesized using IPDI as coupling reagent by two-step method. The copolymers were characterized by IR spectrum and 1H NMR spectrum, and the PEG conjugating ratios of the copolymers were calculated equal to 10% and 30% separately. MTT assay indicated that after PEGylation a lower cytotoxicity of the copolymers could be found, and with increasing PEG conjugating ratio the cytotoxicity decreased obviously. Agarose gel retardation assay demonstrated that PAMAM-PEG copolymers could be combined with DNA and PAMAM-PEG/DNA complexes were prepared by self-assembly. DLS measurement showed that when N/P > or = 50, the particle size of copolymer/ gene complexes was in a range of 150-200 nm, and the zeta potential was in a range of 10-25 mV. In vitro gene transfection illustrated that when N/P < or = 50, the gene transfection efficiency of PAMAM-PEG copolymers was a little less than that of PAMAM-G5, but the transfection efficiency can be raised by increasing N/P ratio or transfection time. Considering both cytotoxicity and transfection efficiency aspects PAMAM-PEG-13 was more effect than PAMAM-PEG-39 in PEGylation.
Carcinoma, Hepatocellular ; pathology ; Cell Line, Tumor ; Cell Survival ; drug effects ; DNA ; chemistry ; pharmacology ; Dendrimers ; chemical synthesis ; pharmacology ; Gene Transfer Techniques ; Genetic Vectors ; Humans ; Isocyanates ; chemistry ; Liver Neoplasms ; pathology ; Particle Size ; Polyamines ; chemistry ; Polyethylene Glycols ; chemical synthesis ; chemistry ; pharmacology ; Transfection

OBJECTIVETo evaluate the effects of polyamidoamine dendrimer (PAMAM) liposome as gene carriers on the cellular uptake and its cytotoxicity in colonic cancer cell.

METHODSThe liposome modified PAMAM was synthesized with liposome and polyamidoamine dendrimer. Plasmid PEGFP-N1 was mixed with the liposome-modified PAMAM or unmodified PAMAM to form nanoparticle complexes. The shape and size of the nanoparticle complexes were observed by transmission electron microscope and the zeta potential was measured by analytical tool. The encapsulating efficiency was determined by ultraviolet spectrophotometer in centrifuging method. After the cell lines SW620 (colonic cancer cell), MCF-7 (breast cancer cell), ECV304 (vascular endothelial cell) were transfected by the two kinds of PAMAM nanoparticle complexes, the flow cytometry was used to determine the uptake of enhanced green fluorescent protein (EGFP) gene. The cytotoxicity of PAMAM liposome nanoparticles and PAMAM nanoparticles was evaluated by MTT assay.

RESULTSThe diameter of liposome modified PAMAM complex was (192 ± 16) nm, and that of PAMAM complex was (189 ± 19) nm (P > 0.05); and the zeta potential of liposome modified PAMAM complex was higher than that of PAMAM complex [(42 ± 7) mV vs. (32 ± 7) mV, P < 0.05]. There was no significant difference in envelopment rate between the two groups [(82 ± 7)% vs. (84 ± 6)%, P > 0.05]. After the colonic cancer cell line SW620 was transfected with the two kinds of PAMAM nanoparticle complexes, the cellular uptake of the cells with the liposome-modified PAMAM complex was significantly higher than that of the cell with PAMAM complex (P < 0.05). The cellular survival rate of the cell lines with liposome-modified PAMAM complex was significantly higher than that of cell lines with PAMAM complex (P < 0.05).

CONCLUSIONThe liposome modified PAMAM can improve gene transfection efficiency and suppress its cytotoxicity.

Cell Line, Tumor ; Cell Survival ; drug effects ; Colonic Neoplasms ; metabolism ; pathology ; Dendrimers ; pharmacokinetics ; toxicity ; Genetic Vectors ; pharmacokinetics ; toxicity ; Humans ; Liposomes ; pharmacokinetics ; toxicity ; Transfection

OBJECTIVETo study the corneal penetration of PAMAM dendrimers-coated puerarin liposomes in rabbits.

METHODEvaluated PAMAM (G2, G3) dendrimers-coated puerarin liposomes were prepared and the in vitro transcorneal penetration were compared to puerarin drop solution and uncoated liposomes. The effect of different proportion of PAMAM to phospholipids in formulation on corneal penetration and the penetration parameters were investigated.

RESULTThe steady state fluxes and permeability coefficients of puerarin by PAMAM G2 (1.0%) and PAMAM G3 (0.5%) coated puerarin liposomes were greater than that by puerarin drop solution and uncoated liposomess (P < 0.01), meanwhile the PAMAM G2 (1.0%) and PAMAM G3 (0.5%) coated liposomes were better than other ratios of coated liposomes for improvement of corneal penetration (P < 0.01).

CONCLUSIONThe PAMAM coated liposomes is able to enhance the corneal penetration of puerarin and promising as an ocular drug carriers.

Animals ; Cornea ; metabolism ; Dendrimers ; chemistry ; metabolism ; In Vitro Techniques ; Isoflavones ; chemistry ; Liposomes ; chemistry ; metabolism ; Rabbits