Artur P. Herman

Magnetic carbon nanostructures in medicine

Magnetic carbon nanostructures are hybrid materials containing magnetic and carbon (mainly sp2) nanoallotrope components conjugated in various configurations. Their potential applications in medicine including drug delivery systems, magnetic particle/fluid hyperthermia anti-cancer therapy and magnetic resonance imaging are reviewed.

An electrically controlled drug delivery system based on conducting poly(3,4-ethylenedioxypyrrole) matrix.

As numerous therapeutic agents are not well tolerated when administrated systemically, localized and controlled delivery can help to decrease their toxicity by applying an optimized drug concentration at extended exposure time. Among different types of drug delivery systems, conjugated polymers are considered as promising materials due to their biocompatibility, electrical conductivity and ability to undergo controllable redox reactions. In this work poly(3,4-ethylenedioxypyrrole), PEDOP, matrix is described for the first time as a reservoir of a model drug, ibuprofen (IBU). Drug immobilization process is performed in situ, during the electrochemical polymerization of 10 mM EDOP in the presence of 5-50 mM IBU. The loading efficiency of polymer matrix is dependent on IBU concentration and reaches 25.0±1.3 μg/cm2. The analysis of PEDOP-IBU chemical structure based on Raman spectroscopy, energy dispersive spectroscopy and surface morphology data provided by scanning electron microscopy shows that IBU is accumulated in the structure of matrix and evidently influences its morphology. IBU is then released in a controlled way under the influence of applied potential (-0.7 V vs. Ag/AgCl). It is demonstrated that the judicious choice of the synthesis conditions leads to a tailored loading efficiency of PEDOP matrix and to a tunable drug release.

Hybrids of Iron-Filled Multiwall Carbon Nanotubes and Anticancer Agents as Potential Magnetic Drug Delivery Systems: In Vitro Studies against Human Melanoma, Colon Carcinoma, and Colon Adenocarcinoma

Cell type, morphology, and functioning are key variables in the construction of efficient “drug-vehicle” hybrids in magnetic drug delivery. Iron-encapsulated multiwall carbon nanotubes (Fe@MWCNTs) appear as promising candidates for theranostics due to in situ chemical catalytic vapor deposition (c-CVD) synthesis, straightforward organic functionalization, and nanoneedle (1D) behavior. Here, model hybrids were synthesized by exploring C-sp2 chemistry ((1

Nitrile N-oxides in programmable one-pot functionalization of multi-wall carbon nanotubes via 1,3-dipolar cycloaddition

Multi-wall carbon nanotubes (MWCNTs) were one-pot functionalized with a series of nitrile N-oxides as 1,3-dipoles carrying diverse functional groups. The degree of functionalization was found to be proportional to MWCNT defectivity. By selection of the 1,3-dipoles, functionalized MWCNTs exhibited programmable affinity to polar or non-polar systems.

Amalgamation of complex iron(III) ions and iron nanoclusters with MWCNTs as a route to potential T2 MRI contrast agents.

Iron-filled multiwall carbon nanotubes (Fe@MWCNTs) were functionalized toward a variety of potential magnetic resonance imaging contrast agents. Oxidized Fe@MWNCTs were covered with PEG5000 via direct esterification or using acyl chloride derivatives. Alternatively, the latter were functionalized with an aminophenol ligand (Fe@O-MWCNT-L). Moreover, pristine Fe@MWCNTs were functionalized with N-phenylaziridine groups (Fe@f-MWCNT) via [2+1] cycloaddition of nitrene. All of these chemically modified nanotubes served as a vehicle for anchoring Fe3+ ions. The new hybrids – Fe(III)/Fe@(f-/O-)MWCNTs – containing 6%–14% of the “tethered” Fe3+ions were studied in terms of the acceleration of relaxation of water protons in nuclear magnetic resonance. The highest transverse relaxivity r2=63.9±0.9 mL mg−1 s−1 was recorded for Fe(III)/Fe@O-MWCNT-L, while for Fe(III)/Fe@f-MWCNT, with r2=57.9±2.9 mL mg−1 s−1, the highest impact of the anchored Fe(III) ions was observed. The T1/T2 ratio of 30–100 found for all of the nanotube hybrids presented in this work is a very important factor for their potential application as T2 contrast agents. Increased stability of the hybrids was confirmed by ultraviolet–visible spectrophotometry.