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Dendrimer-Based Hybrid Nanomaterials for Water Remediation: Adsorption of Inorganic Contaminants
Published in Surender Kumar Sharma, Nanohybrids in Environmental & Biomedical Applications, 2019
Herlys Viltres, Oscar F. Odio, Edilso Reguera
One of the most intensively studied dendrimers in the last decades is poly(amidoamine) (PAMAM), mainly because of its low toxicity, low cost, and accessibility. Lower generations (G1 and G2) comprise flexible molecules with starlike shapes and no appreciable inner regions, while medium-sized generations (G3–G5) exhibit both starlike and spherelike shapes with an internal space separated from the outer shell of the dendrimer. Contrarily, larger generations (> G6) present a clear spherelike shape with large empty inner regions and dense surfaces due to the structure of the outer shell (Gröhn et al., 2000, Kumar et al., 2017b). PAMAM consists of three basic units: an ethylenediamine (EDA) core, repeating units with secondary amide and tertiary amine functions, and terminal primary amine groups (Figure 12.1A). Their synthesis follows a divergent approach and is accomplished by a serial repetition of two reactions: Michael addition of amine groups to the double bond of methyl acrylate (MA), followed by amidation of the resulting methyl ester with EDA molecules. Therefore, each complete reaction sequence results in a new generation with an increase in the dendrimer diameter of about 1 nm. Due to the high density of functional nitrogen groups, the PAMAM dendrimers and their derivatives could display a strong binding affinity for toxic heavy metal ions in aqueous solutions, (Rether and Schuster, 2003) making them favored adsorbents in water purification.
Nanotechnology in wastewater treatment: a review
Published in Badal Jageshwar Prasad Dewangan, Maheshkumar Narsingrao Yenkie, Novel Applications in Polymers and Waste Management, 2018
Bais madhuri, S. P. Singh, R. D. Batra
Invention of dendritic polymers are providing opportunities to develop effective UF processes for purification of water contaminated by toxic metal ions, organic and inorganic solutes, and bacteria and viruses. Poly(amidoamine), or PAMAM, is a class of dendrimer which is made of repetitively branched subunits of amide and amine functionality. PAMAM belongs to the class of water-soluble polymers which is a criteria much needed for the agent in the treatment of water. They can act as floculants for dye industry wastewater treatment. Diallo et al. (2005) tested the feasibility of PAMAM dendrimers with ethylene diamine core and terminal NH2 groups to recover Cu(II) ions from aqueous solutions. On a mass basis, the Cu(II) binding capacities of the PAMAM dendrimers are much larger and more sensitive to solution pH than those of linear polymers with amine groups.1
Medication: Nanoparticles for Imaging and Drug Delivery
Published in Harry F. Tibbals, Medical Nanotechnology and Nanomedicine, 2017
Dendrimers (or dendrons) are repeatedly branched, typically highly symmetric compounds (named from the Greek dendron, meaning “tree”). Unlike most polymers, which are formed by undirected additions of monomer unit building blocks, a dendrimer of any given chemical composition consists of distinct molecules of uniform structure and molecular weight. High molecular weight dendrimer macromolecules may be considered a very special case of polymers; they are also variously referred to as highly branched polymers, hyperbranched polymers, brush polymers, dendrimer star polymers, and dendrimer-like polymers. The importance of dendrimers for medical imaging and drug delivery is that the repeated branches provide multiple uniform and tunable sites for amplification of imaging enhancement and/or drug delivery functionality. Also, their controllable uniform macro-molecular size gives uniform dispersion rates for drug delivery kinetics (monodispersivity) [137-139]. A widely used dendrimer for drug delivery is poly(amidoamine), abbreviated as PAMAM [140].
Recent advances of polymer based nanosystems in cancer management
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Chetan Janrao, Shivani Khopade, Akshay Bavaskar, Shyam Sudhakar Gomte, Tejas Girish Agnihotri, Aakanchha Jain
The proton sponge effect is one of the initial endosomal escape mechanisms (Figure 7) mentioned in the literature. The hypothesis proposed that during the acidification of endosomes, polymers behave as buffering agents and thus prevent the drop in pH, causing cells to pump protons inside endosomes via ATPase to achieve the desired pH. This further results in chloride ions and water molecules influx inside endosomes to maintain balance, which ultimately increases the pressure inside and lyses the endosome. This mechanism is often shown by polycationic materials such as polyethylenimine (PEI), poly(amidoamine) (PAMAM) dendrimers. Xiao et al. formulated zoledronic acid (ZA)-encapsulated polymeric NPs using amphiphilic diblock copolymer such as PLGA-p-PEG due to its biodegradable and biocompatible nature [132,133].