Other Chemistry Commons^™

Cyclic Peptide-Gadolinium Nanocomplexes As Sirna Delivery Tools, Amir Nasrolahi Shirazi, Muhammad Imran Sajid, Dindyal Mandal, David Stickley, Stephanie Nagasawa, Joshua Long, Sandeep Lohan, Keykavous Parang, Rakesh Kumar Tiwari

Pharmacy Faculty Articles and Research

We have recently reported that a cyclic peptide containing five tryptophan, five arginine, and one cysteine amino acids [(WR)₅C], was able to produce peptide-capped gadolinium nanoparticles, [(WR)₅C]-GdNPs, in the range of 240 to 260 nm upon mixing with an aqueous solution of GdCl₃. Herein, we report [(WR)₅C]-GdNPs as an efficient siRNA delivery system. The peptide-based gadolinium nanoparticles (50 µM) did not exhibit significant cytotoxicity (~93% cell viability at 50 µM) in human leukemia T lymphoblast cells (CCRF-CEM) and triple-negative breast cancer cells (MDA-MB-231) after 48 h. Fluorescence-activated cell sorting (FACS) analysis indicated …

Nonlinear Oscillatory Dynamics Of The Hardening Of Calcium Phosphate Bone Cements, Vuk Uskoković, Julietta V. Rau

Pharmacy Faculty Articles and Research

Here we report on the nonlinear, oscillatory dynamics detected in the evolution of phase composition during the setting of different calcium phosphate cements, two of which evolved toward brushite and one toward hydroxyapatite as the final product. Whereas both brushite-forming cements contained iondoped b-tricalcium phosphate as the initial phase, the zinc-containing one yielded scholzite as an additional phase during setting and the oscillations between these two products were pronounced throughout the entire 80 h setting period, long after the hardening processes was over from the mechanical standpoint. Oscillations in the copper-containing system involved the amount of brushite as the main …

Electrochemical Characterization Of Protein Adsorption Onto Yngrt-Au And Vlgxe-Au Surfaces, Hanna Trzeciakiewicz, Jose Esteves-Villanueva, Rania Soudy, Kamaljit Kaur, Sanela Martic-Milne

Pharmacy Faculty Articles and Research

The adsorption of the proteins CD13, mucin and bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN)6]3−/4−. The hydrophobicity of the Au surface was tailored using specific peptides, blocking agents and diluents. The combination of blocking agents (ethanolamine or n-butylamine) and diluents (hexanethiol or 2-mercaptoethanol) was used to prepare various peptide-modified Au surfaces. Protein adsorption onto the peptide-Au surfaces modified with the combination of n-butylamine and hexanethiol produced a dramatic decrease in the charge transfer resistance, Rct, for all three proteins. In contrast, polar peptide-surfaces induced a minimal change in …

The Role Of Hydroxyl Channel In Defining Selected Physicochemical Peculiarities Exhibited By Hydroxyapatite, Vuk Uskoković

Pharmacy Faculty Articles and Research

Mysteries surrounding the most important mineral for the vertebrate biology, hydroxyapatite, are many. Perhaps the Greek root of its name, απαταo, meaning ‘to deceive’ and given to its mineral form by the early gem collectors who confused it with more precious stones, is still applicable today, though in a different connotation, descriptive of a number of physicochemical peculiarities exhibited by it. Comparable to water as the epitome of peculiarities in the realm of liquids, hydroxyapatite can serve as a paradigm for peculiarities in the world of solids. Ten of the peculiar properties of hydroxyapatite are sketched in this review piece, …

Peptide Arrays For Detecting Naphthenic Acids In Oil Sands Process Affected Water, Kamaljit Kaur, Subir Bhattacharjee, Rajesh G. Pillai, Sahar Ahmed, Sarfuddin Azmi

Pharmacy Faculty Articles and Research

Naphthenic acids (NAs) are water-soluble components of petroleum. The characterization and quantification of NAs by analytical methods have proved quite challenging, whilst the toxic effects of these water-soluble compounds on a variety of organisms adversely affecting reproduction and steroid production is becoming apparent. In this study, we report a fluorescence-based competitive binding method for rapid sensing of the presence of NAs using cellulosic peptide array strips as sensors. The peptide array was designed from sequences derived from the estrogen receptor (ER). Several of these peptides were able to detect the presence of NAs at low micromolar (∼5 mg L^{−1 …}

Revisiting The Fundamentals In The Design And Control Of Nanoparticulate Colloids In The Frame Of Soft Chemistry, Vuk Uskoković

Pharmacy Faculty Articles and Research

This review presents thoughts on some of the fundamental features of conceptual models applied in the design of fine particles in the frames of colloid and soft chemistry. A special emphasis is placed on the limitations of these models, an acknowledgment of which is vital in improving their intricacy and effectiveness in predicting the outcomes of the corresponding experimental settings. Thermodynamics of self-assembly phenomena illustrated on the examples of protein assembly and micellization is analyzed in relation to the previously elaborated thesis that each self-assembly in reality presents a co-assembly, since it implies a mutual reorganization of the assembling system …

A New, Simple, Green And One-Pot Four-Component Synthesis Of Bare And Poly(Α, Γ, L-Glutamic Acid) Capped Silver Nanoparticles, Magdalena Stevanović, Igor Savanović, Vuk Uskoković, Srečo D. Škapin, Ines Bračko, Uroš Jovanović, Dragan Uskoković

Pharmacy Faculty Articles and Research

A simple and green chemical method has been developed to synthesize stable bare and capped silver nanoparticles based on the reduction of silver ions by glucose and capping by poly(α,γ,Lglutamic acid) (PGA). The use of ammonia during synthesis was avoided. PGA has had a dual role in the synthesis and was used as a capping agent to make the silver nanoparticle more biocompatible and to protect the nanoparticles from agglomerating in the liquid medium. The synthesized PGA-capped silver nanoparticles in the size range 5–45 nm were stable over long periods of time, without signs of precipitation. Morphological examination has shown …

Quantitative Analysis Of Some Important Metals And Metalloids In Tobacco Products By Inductively Coupled Plasma-Mass Spectrometry (Icp-Ms), Syed Ghulam Musharraf, Muhammad Shoaib, Amna Jabbar Siddiqui, Muhammad Najam-Ul-Haq, Aftab Ahmed

Pharmacy Faculty Articles and Research

Background: Large scale usage of tobacco causes a lot of health troubles in human. Various formulations of tobacco are extensively used by the people particularly in developing world. Besides several toxic tobacco constituents some metals and metalloids are also believed to pose health risks. This paper describes inductively coupled plasma-mass spectrometric (ICP-MS) quantification of some important metals and metalloids in various brands of smoked, sniffed, dipped and chewed tobacco products.

Results: A microwave-assisted digestion method was used for sample preparation. The method was validated by analyzing a certified reference material. Percentage relative standard deviation (% R.S.D.) between recovered …

Pegylated Silicon Nanowire Coated Silica Microparticles For Drug Delivery Across Intestinal Epithelium, Vuk Uskoković, Phin-Peng Lee, Laura Walsh, Kathleen Fischer, Tejal Dasai

Pharmacy Faculty Articles and Research

Composite particles made by growing nanoscopic silicon wires from the surface of monodispersed, microsized silica beads were tested in this study for their ability to affect the integrity and permeability of an epithelial cell layer. Polyethylene glycol (PEG) is known to sterically stabilize particles and prevent protein binding; as such, it is a routine way to impart in vivo longevity to drug carriers. The effect of the silica beads, both with and without silicon nanowires and PEG, on the disruption of the tight junctions in Caco-2 cells was evaluated by means of: (a) analysis of the localization of zonula occludens-1 …

Dynamic Light Scattering And Microelectrophoresis: Main Prospects And Limitations, Vuk Uskoković

Pharmacy Faculty Articles and Research

Microelectrophoresis based on the dynamic light scattering (DLS) effect has been a major tool for assessing and controlling the conditions for stability of colloidal systems. However, both the DLS methods for characterization of the hydrodynamic size of dispersed submicron particles and the theory behind the electrokinetic phenomena are associated with fundamental and practical approximations that limit their sensitivity and information output. Some of these fundamental limitations, including the spherical approximation of DLS measurements and an inability of microelectrophoretic analyses of colloidal systems to detect discrete charges and differ between differently charged particle surfaces due to rotational diffusion and particle orientation …

Dynamic Light Scattering And Zeta Potential Of Colloidal Mixtures Of Amelogenin And Hydroxyapatite In Calcium And Phosphate Rich Ionic Milieus, Vuk Uskoković, Roselyn Odsinada, Sonia Djordjevic, Stefan Habelitz

Pharmacy Faculty Articles and Research

The concept of zeta-potential has been used for more than a century as a basic parameter in controlling the stability of colloidal suspensions, irrespective of the nature of their particulate ingredients – organic or inorganic. There are prospects that self-assembly of peptide species and the protein-mineral interactions related to biomineralization may be controlled using this fundamental physicochemical parameter. In this study, we have analyzed the particle size and zeta-potential of the full-length recombinant human amelogenin (rH174), the main protein of the developing enamel matrix, in the presence of calcium and phosphate ions and hydroxyapatite (HAP) particles. As calcium and phosphate …

A Collection Of Micrographs: Where Science And Art Meet, Vuk Uskoković

Pharmacy Faculty Articles and Research

Micrographs obtained using different instrumental techniques are presented with the purpose of demonstrating their artistic qualities. The quality of uniformity currently dominates the aesthetic assessment in scientific practice and is discussed in relation to the classical appreciation of the interplay between symmetry and asymmetry in arts. It is argued that scientific and artistic qualities have converged and inspired each other throughout millennia. With scientific discoveries and inventions enriching the world of communication, broadening the space for artistic creativity and making artistic products more accessible than ever, science inevitably influences artistic creativity. On the other hand, the importance of aesthetic principles …

Surface Charge Effects Involved In The Control Of Stability Of Sols Comprising Uniform Cholesterol Particles, Vuk Uskoković

Pharmacy Faculty Articles and Research

The reported is a method for the preparation of stable dispersions of narrowly dispersed cholesterol crystals, which may provide an excellent model for the aggregation studies thereof. The effects of experimental parameters that include concentration, pH, ionic strength, temperature, and aging on the resulting morphologies are acknowledged. Regardless of the cause of destabilization, the multilayered aggregates of cholesterol particles are formed by “face-to-face” stacking of the original platelets, as promoted by higher surface charge density on particle sides comparing to their faces. In accordance with the crucial involvement of surface charge effects in stabilization of cholesterol dispersions produced hereby, aggregation …

Four Novel Co-Precipitation Procedures For The Synthesis Of Lanthanum-Strontium Manganites, Vuk Uskoković, Miha Drofenik

Pharmacy Faculty Articles and Research

Lanthanum-strontium manganites were synthesized using co-precipitation method with a reverse micellar microemulsion. Either oxalic acid, sodium hydroxide or tetramethylammonium hydroxide was used for the precipitation of precursor cations in a form that was subsequently calcined under various conditions in order to obtain perovskite manganite phase. Correlations between the properties of the synthesized powder and the calcination conditions have been put forth. The properties of the microemulsion-assisted synthesized material were compared with the samples prepared by following the supposedly similar chemical recombinations in bulk solutions, with an aim to challenge the fact that microemulsions in general have only templating effects on …

Silica-Coated Lanthanum-Strontium Manganites For Hyperthermia Treatments, Vuk Uskoković, Aljoša Košak, Miha Drofenik

Pharmacy Faculty Articles and Research

La_0.76Sr_0.24MnO_{3 + δ} particles, prepared by performing a traditional, solid-state method of synthesis, were coated by uniform layers of silica via initiating hydrolysis and condensation of TEOS in aqueous–alcoholic alkali environment. The eventually obtained samples exhibited Curie temperature at ∼40 °C, and comprised core-shell particles of ∼250 nm in diameter. By varying stoichiometric ratio of cations within manganite cores of the particles, Curie point of the resulting material can be varied too, thus opening a way for the simple design of biocompatible, temperature-self-regulating particles for application in hyperthermia treatments, with Curie point thereof adjusted to …

Synthesis Of Lanthanum-Strontium Manganites By Oxalate-Precursor Co-Precipitation Methods In Solution And In Reverse Micellar Microemulsion, Vuk Uskoković, Miha Drofenik

Pharmacy Faculty Articles and Research

Nanostructured lanthanum–strontium manganites were synthesized using two different co-precipitation approaches, one in bulk solution, and the other in reverse micelles of CTAB/1-hexanol/water microemulsion. In both cases, precursor cations were precipitated by using oxalic acid. The properties of the materials synthesized by using these two methods were compared in order to reveal potential advantages of the microemulsion-assisted approach. The influence of the annealing conditions on the properties of synthesized manganites was investigated by using X-ray diffraction, transmission electron microscopy, differential thermal analysis, thermogravimetric analysis and magnetic measurements.

Mechanism Of A Solid-State Formation Of La1-Xsrxmno3+Δ (0 < X < 0.5) And Magnetic Characterization Thereof, Vuk Uskoković, Miha Drofenik

Pharmacy Faculty Articles and Research

Rich diversity of potential, substantially different micro-structural arrangements - reflecting on the wide potential set of interesting properties, ranging from high electrical conductivity to giant, collossal and/or low-field magnetoresistance to low Curie point - of LaSr-manganite materials opens possibilities for numerous scientific investigations oriented towards revealing correlations on the influence line: procedure of synthesis → inherent properties → measured properties → application of the material. The investigations of the influence of synthesis procedures and LaSr-manganite stoichiometries on the Curie point (and other magnetic characteristics) of the material, being the topic of this work, are attractive since they present a necessary …

Preparation Of Silica-Coated Lanthanum-Strontium Manganite Particles With Designable Curie Point, For Application In Hyperthermia Treatments, Vuk Uskoković, Aljoša Košak, Miha Drofenik

Pharmacy Faculty Articles and Research

Silica-coated lanthanum–strontium manganite particles with La_0.76Sr_0.24MnO_3+δ stoichiometric formula, exhibiting Curie temperature at ∼40°C, were prepared by using a traditional solid-state method of synthesis of magnetic ceramic particles, followed by milling and a low-temperature coating procedure in an aqueous alcoholic alkali medium. The properties of the obtained material establish it as a potential candidate for self-regulated power-absorbing and temperature-controlling materials in hyperthermia treatments. Moreover, core-comprising LaSr–manganites with different stoichiometries, ranging from La_0.5Sr_0.5MnO_3+δ to LaMnO_3+δ, were synthesized, with magnetic and structural properties examined thereof. Herein reported findings can potentially be …

A Mechanism For The Formation Of Nanostructured Nizn Ferrites Via A Microemulsion-Assisted Precipitation Method, Vuk Uskoković, Miha Drofenik

Pharmacy Faculty Articles and Research

Nanostructured NiZn ferrites were synthesized using two different techniques: first, a precipitation procedure in the reverse micelles of a CTAB/1-hexanol/H₂O microemulsion, and second, precipitation in a bulk aqueous solution. XRD measurements, magnetic measurements, TEM imaging, analytical measurements and thermal analyses were used in an attempt to reveal the chemical pathway that leads to the formation of NiZn ferrite in the microemulsion and in the bulk aqueous solution. It was found that reverse micelles do not act as inert nano-sized reactors that influence only morphological properties of the synthesized powders, but have a decisive influence on the identity of …

Synthesis Of Lanthanum-Strontium Magnanites By A Hydroxide-Precursor Co-Precipitation Method In Solution And In Reverse Micellar Microemulsion, Vuk Uskoković, Darko Makovec, Miha Drofenik

Pharmacy Faculty Articles and Research

Nanostructured lanthanum-strontium manganites have been synthesized using two different co-precipitation approaches, one in bulk solution, and the other in reverse micelles of CTAB/1-hexanol/1-butanol/water microemulsion. In both cases, precursor cations were precipitated by alkali precipitating agents. The properties of the material synthesized by using these two methods were compared in order to reveal potential advantages of microemulsion-assisted approach. The influence of the annealing conditions on the properties of synthesized manganites was investigated by using X-ray diffraction, transmission electron microscopy, differential thermal analysis, thermogravimetric analysis and magnetic measurements.

Synthesis Of Relatively Highly Magnetic Nano-Sized Nizn-Ferrite In Microemulsion At 45 Oc, Vuk Uskoković, Miha Drofenik

Pharmacy Faculty Articles and Research

The procedure for the preparation of NiZn-ferrite powder with average particle size of 10 nm and saturation magnetization of 50 emu/g by using precipitation reaction between acidified sulphate precursor salts and NH4OH as the precipitating agent in the water-in-oil domain of the microemulsion CTAB/1-hexanol/water at 45 oC is presented herein. TEM measurements have revealed relatively uniform morphology of the particles, which are associated in coral-like agglomerates. EDS measurements have been used for qualitative analysis of the sample, whereby FAAS measurement has been performed in order to reveal the proportion of the cations in the sample - Ni : Zn : …

The Characterization Of Nanosized Nickel-Zinc Ferrites Synthesized Within Reverse Micelles Of Ctab/1-Hexanol/Water Microemulsion, Vuk Uskoković, Miha Drofenik, Irena Ban

Pharmacy Faculty Articles and Research

Stoichiometric nanocrystalline nickel–zinc ferrites were synthesized by a reverse micelle method following a multi-microemulsion approach. Different pH values were chosen for the alkali precipitating reaction during the synthesis of different powders. Synthesized, as-dried and subsequently calcined powders were characterized in terms of their magnetic properties. XRD analyses and specific-surface area measurements were used to determine the average particle sizes of the synthesized samples. DCS and TGA measurements were performed to reveal the phase transitions within the samples at elevated temperatures, whereas TEM was used to view and record the microstructure of the nanosized ferrite samples. A possible mechanism of the …

Synthesis Of Nanocrystalline Nickel-Zinc Ferrites Via A Microemulsion Route, Vuk Uskoković, Miha Drofenik

Pharmacy Faculty Articles and Research

Nanostructured NiZn-ferrites were synthesized using a low-temperature co-precipitation method within the reverse micelles of ternary CTAB/1-hexanol/water microemulsions. The influence of pH on the precipitation reaction was investigated. It was found that a higher pH resulted in more crystalline particles. Subsequent oxidation of the ferrous ions precipitate, which leads to the formation of spinel ferrites, is discussed. Diffraction-lines broadening and specific surface area measurements yielded an average particle size of ~ 3 nm. The saturation magnetization of the samples was 20 times smaller than for traditionally synthesized NiZn-ferrites, while the coercivities were 10 - 100 times larger than bulk NiZn-ferrites, which …

Synthesis And Characterization Of Hydroxyapatite-Collagen Biocomposite Materials, Vuk Uskoković, Nenad Ignjatović, Nadejda Petranović

Pharmacy Faculty Articles and Research

Hydroxyapatite-collagen composite is a prosperous biomaterial in reconstructive surgery for the reparation of defects within human hard tissue. Within this research, three-dimensional blocks of HAp/collagen composite biomaterial were synthesized by homogenizing the HAp/collagen mixture by cold and hot (T=60oC) pressing (P=49 MPa). The changes in the system were followed by using thermal analysis (DSC & TGA), FT-IR spectroscopy and scanning electron microscopy (SEM). The identification and kinetic analysis of appearing phase transition were done. FT-IR spectrum of the biocomposite shows that neither cold nor hot pressing had significant influence on the individual components of the composite. SEM of the fracture …

Protein Adducts Of Iso[4]Levuglandin E2, A Product Of The Isoprostane Pathway, In Oxidized Low Density Lipoprotein, Robert G. Salomon, Wei Sha, Cynthia Brame, Kamaljit Kaur, Ganesamoorthy Subbanagounder, June O'Neil, Henry F. Hoff, L. Jackson Roberts Ii

Pharmacy Faculty Articles and Research

Levuglandin (LG) E₂, a cytotoxic seco prostanoic acid co-generated with prostaglandins by nonenzymatic rearrangements of the cyclooxygenase-derived endoperoxide, prostaglandin H₂, avidly binds to proteins. That LGE₂-protein adducts can also be generated nonenzymatically is demonstrated by their production during free radical-induced oxidation of low density lipoprotein (LDL). Like oxidized LDL, LGE₂-LDL, but not native LDL, undergoes receptor-mediated uptake and impaired processing by macrophage cells. Since radical-induced lipid oxidation produces isomers of prostaglandins, isoprostanes (isoPs), via endoperoxide intermediates, we postulated previously that a similar family of LG isomers, isoLGs, is cogenerated with isoPs. Now …