Publications by Year: 2012

2012
Jin Z, Guven G, Bocharova V, Halamek J, Tokarev I, Minko S, Melman A, Mandler D, Katz E. Electrochemically controlled drug-mimicking protein release from iron-alginate thin-films associated with an electrode. ACS Appl Mater InterfacesACS applied materials & interfaces. 2012;4 (1) :466 - 75.Abstract
Novel biocompatible hybrid-material composed of iron-ion-cross-linked alginate with embedded protein molecules has been designed for the signal-triggered drug release. Electrochemically controlled oxidation of Fe(2+) ions in the presence of soluble natural alginate polymer and drug-mimicking protein (bovine serum albumin, BSA) results in the formation of an alginate-based thin-film cross-linked by Fe(3+) ions at the electrode interface with the entrapped protein. The electrochemically generated composite thin-film was characterized by electrochemistry and atomic force microscopy (AFM). Preliminary experiments demonstrated that the electrochemically controlled deposition of the protein-containing thin-film can be performed at microscale using scanning electrochemical microscopy (SECM) as the deposition tool producing polymer-patterned spots potentially containing various entrapped drugs. Application of reductive potentials on the modified electrode produced Fe(2+) cations which do not keep complexation with alginate, thus resulting in the electrochemically triggered thin-film dissolution and the protein release. Different experimental parameters, such as the film-deposition time, concentrations of compounds and applied potentials, were varied in order to demonstrate that the electrodepositon and electrodissolution of the alginate composite film can be tuned to the optimum performance. A statistical modeling technique was applied to find optimal conditions for the formation of the composite thin-film for the maximal encapsulation and release of the drug-mimicking protein at the lowest possible potential.[on SciFinder (R)]
Wang Z, Zhang J, Yin Z, Wu S, Mandler D, Zhang H. Fabrication of nanoelectrode ensembles by electrodepositon of Au nanoparticles on single-layer graphene oxide sheets. NanoscaleNanoscale. 2012;4 (8) :2728 - 33.Abstract
Nanoelectrode ensembles (NEEs) have been fabricated by the electrodeposition of Au nanoparticles (AuNPs) on single-layer graphene oxide (GO) sheets coated on a glassy carbon electrode (GCE). The fabricated NEEs show a typical sigmoidal shaped voltammetric profile, arising from the low coverage density of AuNPs on GCE and large distance among them, which can be easily controlled by varying the electrodeposition time. As a proof of concept, after the probe HS-DNA is immobilized on the NEEs through the Au-S bonding, the target DNA is detected with the methylene blue intercalator. Our results show that the target DNA can be detected as low as 100 fM, i.e. 0.5 amol DNA in 5 μL solution.[on SciFinder (R)]
Jaber N, Lesniewski A, Gabizon H, Shenawi S, Mandler D, Almog J. Visualization of latent fingermarks by nanotechnology: reversed development on paper--a remedy to the variation in sweat composition. Angew Chem Int Ed EnglAngewandte Chemie (International ed. in English). 2012;51 (49) :12224 - 7.
Jin Z, Guven G, Bocharova V, Halamek J, Tokarev I, Minko S, Melman A, Mandler D, Katz E. Electrochemically Controlled Drug-Mimicking Protein Release from Iron-Alginate Thin-Films Associated with an Electrode. ACS Appl. Mater. InterfacesACS Applied Materials & Interfaces. 2012;4 (1) :466 - 475.Abstract
Novel biocompatible hybrid-material composed of iron-ion-crosslinked alginate with embedded protein mols. has been designed for the signal-triggered drug release. Electrochem. controlled oxidn. of Fe2+ ions in the presence of sol. natural alginate polymer and drug-mimicking protein (bovine serum albumin, BSA) results in the formation of an alginate-based thin-film crosslinked by Fe3+ ions at the electrode interface with the entrapped protein. The electrochem. generated composite thin-film was characterized by electrochem. and at. force microscopy (AFM). Preliminary expts. demonstrated that the electrochem. controlled deposition of the protein-contg. thin-film can be performed at microscale using scanning electrochem. microscopy (SECM) as the deposition tool producing polymer-patterned spots potentially contg. various entrapped drugs. Application of reductive potentials on the modified electrode produced Fe2+ cations which do not keep complexation with alginate, thus resulting in the electrochem. triggered thin-film dissoln. and the protein release. Different exptl. parameters, such as the film-deposition time, concns. of compds. and applied potentials, were varied in order to demonstrate that the electrodeposition and electrodissoln. of the alginate composite film can be tuned to the optimum performance. A statistical modeling technique was applied to find optimal conditions for the formation of the composite thin-film for the maximal encapsulation and release of the drug-mimicking protein at the lowest possible potential. [on SciFinder(R)]
Wang Z, Zhang J, Yin Z, Wu S, Mandler D, Zhang H. Fabrication of nanoelectrode ensembles by electrodeposition of Au nanoparticles on single-layer graphene oxide sheets. NanoscaleNanoscale. 2012;4 (8) :2728 - 2733.Abstract
Nanoelectrode ensembles (NEEs) have been fabricated by the electrodeposition of Au nanoparticles (AuNPs) on single-layer graphene oxide (GO) sheets coated on a glassy carbon electrode (GCE). The fabricated NEEs show a typical sigmoidal shaped voltammetric profile, arising from the low coverage d. of AuNPs on GCE and large distance among them, which can be easily controlled by varying the electrodeposition time. As a proof of concept, after the probe HS-DNA is immobilized on the NEEs through the Au-S bonding, the target DNA was detected with the methylene blue intercalator. The authors' results show that the target DNA can be detected as low as 100 fM, i.e. 0.5 amol DNA in 5 μL soln. [on SciFinder(R)]
Jaber N, Lesniewski A, Gabizon H, Shenawi S, Mandler D, Almog J. Visualization of Latent Fingermarks by Nanotechnology: Reversed Development on Paper-A Remedy to the Variation in Sweat Composition. Angew. Chem., Int. Ed.Angewandte Chemie, International Edition. 2012;51 (49) :12224 - 12227.Abstract
In this work, "neg." fingermarks have been developed on paper, even after soaking in water, by the application of a new bifunctional reagent attached to gold nanoparticles, and then a silver phys. developer. The bifunctional reagent is composed of an active head, i.e., a polar group with high affinity to cellulose, attached by a long chain to an active tail contg. a sulfur group, which can stabilize gold nanoparticles. Through the active head, the gold nanoparticles, which are stabilized by the active tail, adhere preferentially to the paper cellulose rather than to the fingerprint material, to which they conventionally bind. Consequently, silver developer, which normally develops sebaceous fingermarks by pptg. dark silver on the sebaceous material, ppt. preferentially on the gold-coated areas giving rise to the appearance of uncolored ridge detail on a dark background. In this competing process, the paper itself serves as the substrate, whereas the fingermarks serve as a mask. This process may increase the overall yield of developed fingermarks as it bypasses the issue of the remarkable differences in sweat compn. between individual persons. [on SciFinder(R)]