In-situ immobilization of silver nanoparticles on ZSM-5 type zeolite by catechol redox chemistry, a green catalyst for A³-coupling reaction

GhavamiNejad, A.,Kalantarifard, A.,Yang, G.S.,Kim, C.S. Elsevier 2016 Microporous and mesoporous materials Vol.225 No.-

<P>For the first time in literature, we used a mussel-inspired surface chemistry for the production of propargylamines by the immobilization of silver nanoparticles (AgNPs) on the surface of mesoporous ZSM-5 zeolite. The ZSM-5 zeolite has a large surface area with a porous structure and provides a sufficient reaction space for monodisperse silver nanoparticles, resulting in high catalytic activity for the production of propargylamines with a shorter reaction time. The catalyst was recovered easily and could be used for three cycles without any significant loss in catalytic activity. N-2 adsorption/desorption, ICP-AES, XRD, XPS, FE-SEM, TEM and FT-IR experiments were carried out to characterize the heterogeneous catalysts of this study. (C) 2016 Elsevier Inc. All rights reserved.</P>

In Situ Synthesis of Antimicrobial Silver Nanoparticles within Antifouling Zwitterionic Hydrogels by Catecholic Redox Chemistry for Wound Healing Application

GhavamiNejad, Amin,Park, Chan Hee,Kim, Cheol Sang American Chemical Society 2016 Biomacromolecules Vol.17 No.3

<P>A multifunctional hydrogel that combines the dual functionality of both antifouling and antimicrobial capacities holds great potential for many bioapplications. Many approaches and different materials have been employed to synthesize such a material. However, a systematic study, including in vitro and in vivo evaluation, on such a material is wound dressings is highly scarce at present Herein, we report on a new strategy that uses catecholic chemistry to synthesize antimicrobial silver nanoparticles impregnated into antifouling zwitterionic hydrogels. For this purpose, hydrophobic dopamine methacrylamide monomer (DMA) was mixed in an aqueous solution of sodium tetraborate decahydrate and DMA monomer became soluble after increasing pH to 9 due to the complexation between catechol groups and boron. Then, cross-linking polymerization of zwitterionic monomer was carried out with the solution of the protected dopamine monomer to produce a new hydrogel. When this new hydrogel comes in contact with a silver nitrate solution, silver nanoparticles (AgNPs) are formed in its structure as a result of the redox property of the catechol groups and in the absence of any other external reducing,agent. The results obtained from TEM and XRD measurements indicate that AgNPs with diameters of around 20 nm had formed within the networks. FESEM images confirmed that the silver nanoparticles were homogeneously incorporated throughout the hydrogel network, and FTIR spectroscopy demonstrated that the catechol moiety in the polymeric backbone of the hydrogel is responsible for the reduction of silver ions into the AgNPs. Finally, the in vitro and in vivo experiments suggest that these mussel-inspired, antifouling, antibacterial hydrogels have great potential for use in wound healing applications.</P>

Mussel-Inspired Electrospun Nanofibers Functionalized with Size-Controlled Silver Nanoparticles for Wound Dressing Application

GhavamiNejad, Amin,Rajan Unnithan, Afeesh,Ramachandra Kurup Sasikala, Arathyram,Samarikhalaj, Melisa,Thomas, Reju George,Jeong, Yong Yeon,Nasseri, Saeed,Murugesan, Priya,Wu, Dongmei,Hee Park, Chan,Kim American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.22

<P>Electrospun nanofibers that contain silver nanoparticles (AgNPs) have a strong antibacterial activity that is beneficial to wound healing. However, most of the literature available on the bactericidal effects of this material is based on the use of AgNPs with uncontrolled size, shape, surface properties, and degree of aggregation. In this study, we report the first versatile synthesis of novel catechol moieties presenting electrospun nanofibers functionalized with AgNPs through catechol redox chemistry. The synthetic strategy allows control of the size and amount of AgNPs on the surface of nanofibers with the minimum degree of aggregation. We also evaluated the rate of release of the AgNPs, the biocompatibility of the nanofibers, the antibacterial activity in vitro, and the wound healing capacity in vivo. Our results suggest that these silver-releasing nanofibers have great potential for use in wound healing applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-22/acsami.5b02542/production/images/medium/am-2015-02542w_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am5b02542'>ACS Electronic Supporting Info</A></P>

Supramolecular Interaction Controlled Diffusion Mechanism and Improved Mechanical Behavior of Hybrid Hydrogel Systems of Zwitterions and CNT

Hashmi, Saud,GhavamiNejad, Amin,Obiweluozor, Francis O.,Vatankhah-Varnoosfaderani, Mohammad,Stadler, Florian J. American Chemical Society 2012 Macromolecules Vol.45 No.24

<P>Hybrid hydrogels of poly(<I>N</I>-isopropylacrylamide) (pNIPAM) containing carboxylate carbon nanotubes (CNTs) and/or zwitterions are synthesized by free radical polymerization. The supramolecular interactions among zwitterionic monomers and CNTs influence the mechanical properties and diffusion mechanism in hybrid hydrogel systems. These supramolecular interactions and response behavior of hybrid hydrogels were tested mechanically and with respect to their swelling characteristics. Hybrid hydrogels of pNIPAM and CNT or pNIPAM, zwitterions, and CNT follow a Fickian diffusion behavior, while adding zwitterions leads to an anomalous triple-stage swelling behavior and stiffening of the gel due to the interactions of the zwitterions with each other, which significantly increase the viscous dissipation and change the microscopic structure. While CNT itself stiffens the gel and slightly increases the diffusion speed, it complexes zwitterions, which leads to a novel property profile that is both potentially antibiotic and electrically conductive. CNT affords a relaxation process at long relaxation times, while zwitterion attachment and detachment lead to dissipation predominantly at high frequencies. Dynamic rheological measurements were performed during swelling of these complex materials.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2012/mamobx.2012.45.issue-24/ma301366h/production/images/medium/ma-2012-01366h_0014.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma301366h'>ACS Electronic Supporting Info</A></P>

A smart magnetic nanoplatform for synergistic anticancer therapy: manoeuvring mussel-inspired functional magnetic nanoparticles for pH responsive anticancer drug delivery and hyperthermia.

Sasikala, Arathyram Ramachandra Kurup,GhavamiNejad, Amin,Unnithan, Afeesh Rajan,Thomas, Reju George,Moon, Myeongju,Jeong, Yong Yeon,Park, Chan Hee,Kim, Cheol Sang RSC Pub 2015 Nanoscale Vol.7 No.43

<P>We report the versatile design of a smart nanoplatform for thermo-chemotherapy treatment of cancer. For the first time in the literature, our design takes advantage of the outstanding properties of mussel-inspired multiple catecholic groups -presenting a unique copolymer poly(2-hydroxyethyl methacrylateco-dopamine methacrylamide) p(HEMA-co-DMA) to surface functionalize the superparamagnetic iron oxide nanoparticles as well as to conjugate borate containing anticancer drug bortezomib (BTZ) in a pH-dependent manner for the synergistic anticancer treatment. The unique multiple anchoring groups can be used to substantially improve the affinity of the ligands to the surfaces of the nanoparticles to form ultrastable iron oxide nanoparticles with control over their hydrodynamic diameter and interfacial chemistry. Thus the BTZ-incorporated-bio-inspired-smart magnetic nanoplatform will act as a hyperthermic agent that delivers heat when an alternating magnetic field is applied while the BTZ-bound catechol moieties act as chemotherapeutic agents in a cancer environment by providing pH-dependent drug release for the synergistic thermo-chemotherapy application. The anticancer efficacy of these bio-inspired multifunctional smart magnetic nanoparticles was tested both in vitro and in vivo and found that these unique magnetic nanoplatforms can be established to endow for the next generation of nanomedicine for efficient and safe cancer therapy.</P>

On-demand drug release and hyperthermia therapy applications of thermoresponsive poly-(NIPAAm-co-HMAAm)/polyurethane core-shell nanofiber mat on non-vascular nitinol stents

Aguilar, Ludwig Erik,GhavamiNejad, Amin,Park, Chan Hee,Kim, Cheol Sang Elsevier 2017 NANOMEDICINE Vol.13 No.2

<P><B>Abstract</B></P> <P>A functional cover made up of core-shell nanofibers with a unique combination of thermoresponsive polymeric shell and stretchable polymeric core for non-vascular nitinol stents that uses an alternating magnetic field (AMF) to induce heat in the stent for hyperthermia therapy and simultaneously release 5-fluorouracil and/or paclitaxel was designed. Varying the ratios of NIPAAm to HMAAm monomer resulted in different LCST properties for the synthesized copolymer and further utilized for an on-demand drug release. Biocompatibility test using NIH-3T3 fibroblast cells indicates that the composite with drug content is biocompatible and the in-vitro cancer cytotoxicity test using ESO26 and OE21 cancer cells proved that the material shows cancer cytotoxic properties via combination of dual drug and hyperthermia therapy. With this functional material, we propose a tailorable and on-demand drug release with more control that can be employed for a combination drug therapy/single drug therapy combined with hyperthermia therapy for cancer cytotoxicity effect.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First time in literature that poly(NIPAAm-co-HMAAm) nanofibers was used as a stent cover. </LI> <LI> Loading two different chemotherapeutic drugs on poly(NIPAAm-co-HMAAm) with two different LCST points creates an on-demand and tailorable drug delivery. </LI> <LI> Unique combination of Thermoresponsive polymer and Mechanically stable polymer on a core-shell nanofiber. </LI> <LI> Combination of Alternating Field Induced hyperthermia and Chemotherapy on a nitinol stent for cancer cytotoxic effects. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>On-demand drug release and hyperthermia therapy applications of thermoresponsive poly-(NIPAAm-co-HMAAm)/polyurethane core-shell nanofiber mat on non-vascular nitinol stents.</P> <P>[DISPLAY OMISSION]</P>

Mussel-inspired pH-triggered reversible foamed multi-responsive gel – the surprising effect of water

Vatankhah-Varnoosfaderani, Mohammad,GhavamiNejad, Amin,Hashmi, Saud,Stadler, Florian J. The Royal Society of Chemistry 2013 Chemical communications Vol.49 No.41

<P>Novel covalent gels were prepared by complexation of polymer-bound catechols with NaBH<SUB>4</SUB> at pH ≈ 9. These gels can absorb humidity, which changes the catechol–borate covalent bonds from irreversible to reversible. Furthermore, humidity induces self-healing, proven by rheological data.</P> <P>Graphic Abstract</P><P>Humidity induced sol–gel reversibility and improved self-healing behavior of a novel supramolecular organogel produced by complexation of catechol with NaBH<SUB>4</SUB>. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3cc41332b'> </P>

On-line Observation of Hydrogels during Swelling and LCST-induced changes

Hashmi, Saud,Obiweluozor, Francis,GhavamiNejad, Amin,Vatankhah-Varnoosfaderani, Mohammad,Stadler, Florian J. 한국유변학회 2012 Korea-Australia rheology journal Vol.24 No.3

A new technique for the online observation of rheological data of hydrogels during experiments involving significant volume changes is proposed. In order to accommodate for large volume changes, the gap has to be force controlled and continuously adjusted to the current sample height. Furthermore, the force control also has to ensure the adhesion of the sample to the geometry. For smaller volume changes, it is also possible to employ experiments with constant gap. Due to the volume change, the sample is not clearly defined with respect to the open surfaces in a parallel plate geometry, which leads to too high values, which, however, can be compensated for properly.

Rapid self-healing and triple stimuli responsiveness of a supramolecular polymer gel based on boron-catechol interactions in a novel water-soluble mussel-inspired copolymer

Vatankhah-Varnoosfaderani, M.,Hashmi, S.,GhavamiNejad, A.,Stadler, F. Royal Society of Chemistry 2014 Polymer chemistry Vol.5 No.2

Marine and freshwater mussels secrete proteinaceous adhesive materials for adherence to the substrates upon which they reside. It is well known that 3,4-dihydroxyphenylalanine (DOPA) is the key to understanding these mussel adhesive proteins (MAPs). In order to gain a better understanding of their complex formation and quick recovery upon rupturing, novel water soluble copolymers of N-isopropylacrylamide and dopamine methacrylate were synthesized in such a way that they have 1, 2.5, and 5 mole percent dopamine monomer with respect to the NIPAM monomer on average. The statistical distribution of DOPA-functionalities along the chain makes the material a close synthetic equivalent of the byssal thread proteins of mytili. At acidic pH, the aqueous copolymer solution behaves like an unentangled copolymer solution, but at basic pH, these catechol functionalities form a dicomplex with H3BO3, thereby crosslinking two chains, proven by B-11-NMR and gelation. The polymer solution is thermosensitive with a pH-dependent lower critical solution temperature (LCST) between 21 and 33 degrees C, depending on the DOPA-content. If 2 or more functionalities per chain are present, a gel is formed that is self-healing with very quick recovery from sustained damage. The moduli of the gels depend on the concentration of functionalities. Hence, triple stimuli responsive copolymers were obtained.