Alignment of lyotropic liquid crystals using magnetic nanoparticles improves ionic transport through built-in peptide ion channels.

HYPOTHESIS: We hypothesize that simultaneous incorporation of ion channel peptides (in this case, potassium channel as a model) and hydrophobic magnetite Fe3O4 nanoparticles (hFe3O4NPs) within lipidic hexagonal mesophases, and aligning them using an external magnetic field can significantly enhance ion transport through lipid membranes. EXPERIMENTS: In this study, we successfully characterized the incorporation of gramicidin membrane ion channels and hFe3O4NPs in the lipidic hexagonal structure using SAXS and cryo-TEM methods. Additionally, we thoroughly investigated the conductive characteristics of freestanding films of lipidic hexagonal mesophases, both with and without gramicidin potassium channels, utilizing a range of electrochemical techniques, including impedance spectroscopy, normal pulse voltammetry, and chronoamperometry. FINDINGS: Our research reveals a state-of-the-art breakthrough in enhancing ion transport in lyotropic liquid crystals as matrices for integral proteins and peptides. We demonstrate the remarkable efficacy of membranes composed of hexagonal lipid mesophases embedded with K+ transporting peptides. This enhancement is achieved through doping with hFe3O4NPs and exposure to a magnetic field. We investigate the intricate interplay between the conductive properties of the lipidic hexagonal structure, hFe3O4NPs, gramicidin incorporation, and the influence of Ca2+ on K+ channels. Furthermore, our study unveils a new direction in ion channel studies and biomimetic membrane investigations, presenting a versatile model for biomimetic membranes with unprecedented ion transport capabilities under an appropriately oriented magnetic field. These findings hold promise for advancing membrane technology and various biotechnological and biomedical applications of membrane proteins.

A theranostic system based on nanocomposites of manganese oxide nanoparticles and a pH sensitive polymer: Preparation, and physicochemical characterization.

A multifunctional nanocomposite theranostic system is constructed of manganese oxide (Mn3O4) nanoparticles (NPs), as a tumor diagnostic agent, in conjunction with polyacrylic acid (PAA), as a pH-sensitive drug delivery agent, and methotrexate (MTX), as a model of targeting agent and anticancer drug. Physicochemical characteristics of the Mn3O4@PAA/MTX system is studied in detail by several techniques, including X-ray and Auger photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and electrochemical methods. The system performance is studied based on (i) in-vitro MRI measurements to support efficiency of the Mn3O4@PAA NPs as a diagnostic agent, (ii) drug release performance of the Mn3O4@PAA/MTX NPs at pHs of 5.4 and 7.4 through in-vitro method to evaluate application of the NPs as pH-sensitive nanocarriers for MTX, and (iii) impedance spectroscopy measurements to show Mn3O4@PAA/MTX NPs affinity for capturing of cancer cells. The results show that (i) Mn3O4@PAA NPs can be used as a contrast agent in MRI measurements (r1 ≅ 6.5 mM-1 s-1), (ii) the MTX, loaded on Mn3O4@PAA NPs, is released faster and more efficient at pH 5.4 than 7.4, and (iii) the GC-Mn3O4@PAA/MTX electrode system captures the 4T1 cells 3.32 times larger than L929 cells.

Construction and characterization of a theranostic system based on graphene/manganese chelate.

Construction of hybrid systems that combine the cancer treatment and diagnosis agents on a single platform, known as theranostic systems, have received great attentions in the field of nanobiomedicine. Here, construction and characterization of a new multifunctional hybrid theranostic system based on RGO, PDA, BSA, DTPA-Mn(II), and MTX constituents, is presented. Accordingly, GO is partially reduced and simultaneously functionalized by dopamine, leading to reduced graphene oxide/polydopamine, RGO-PDA system; and then, the bovine serum albumin protein (BSA) is grafted onto this system. The obtained system, RGO-PDA-BSA, is further decorated with diethylenetriaminepentaacetic acid-Mn(II) as diagnostic system and methotrexate as anticancer drug. Physicochemical characteristics of the RGO-PDA-BSA-DTPA-Mn(II)/MTX system are studied by Fourier transform infrared spectroscopy, atomic force microscopy, and electrochemical methods. The capturing ability of the prepared system for the cancer cells is evaluated through electrochemical impedance spectroscopy (EIS) and by using the 4T1 cancer cells in comparison with L929 normal cells. The EIS results indicate that a degree of selectivity as 6.23 for GC-RGO-PDA-BSA-DTPA-Mn(II)/MTX electrode system toward 4T1 cells, which is larger than that obtained for this system toward the L929 cells. Similar analysis performed using the GC-RGO-PDA-DTPA-Mn(II)/MTX system (having no BSA) indicate that the selectivity degree of the system is increased only by a factor of 1.6, implying that presence of BSA has increased the selectivity of the system for 4T1 cells by a factor of four. This behavior supports the crucial role of BSA in this process for 4T1 cells. Finally, the drug release study of RGO-PDA-BSA-DTPA-Mn(II)/MTX system is performed successfully at pH 7.4.

Controlled synthesis of mixed molecular nanostructures from folate and deferrioxamine-Ga(III) on gold and tuning their performance for cancer cells.

A new strategy is developed for construction of the mixed molecular nanostructures from folic acid (FOA), a targeting agent, and deferrioxamoine-Ga(III), (DFO-Ga(III)), a theranostic agent, on gold-mercaptopropionic acid surface, Au-MPA. The strategy is focused to achieve a system in which all the active constituents of FOA; i.e., pteridine rings, p-aminobenzoeic acid, and the glutamic acid, having high affinity for folate receptor overexpressed on cancer cells; remain unreacted in adjacent to DFO-Ga(III), Au-MPA-[DFO-Ga(III)]‖-[FOA]. For this purpose, the NH2 groups of FOA and DFO-Ga(III) were attached covalently and separately to COOH of Au-MPA surface allowing all the active groups of FOA to be available for drug delivery purposes. The data obtained through several electrochemical and surface analysis techniques, supported successful construction of the designed mixed molecular nanostructures system. In addition, the results showed that the system is stable, and Ga(III) ion does not leave DFO-Ga(III) complex. The prepared surface was successfully tested for capturing of the breast cancer cells 4T1 as a model. The measurements showed a rapid uptake kinetics (t1/2 of ~6.0min) and efficient accessibility of the system by the cancer cells; the Rct was significantly increased in the presence of 4T1 cells compared with blank PBS (ΔRct ~420kΩ).

Immobilization of methotrexate anticancer drug onto the graphene surface and interaction with calf thymus DNA and 4T1 cancer cells.

Immobilization of methotrexate (MTX) anticancer drug onto the graphene surface is reported through three methods, including either covalent linkage via (a) EDC/NHS organic activators and (b) electrografting of MTX diazonium salt, or (c) noncovalent bonding, resulting in three different systems. To evaluate the interaction ability of the immobilized MTX with biological species, calf thymus DNA (ctDNA), mouse 4T1 breast tumor, and Human foreskin fibroblast (hFF) cells as models of the primary intracellular target of anticancer drugs, cancer and normal cells, respectively, are examined. The features of the constructed systems and their interactions with ctDNA are followed by surface analysis techniques and electrochemical methods. The results indicate that (i) the amount of the immobilized MTX on the graphene surface is affected by type of the immobilization method; and a maximum value of (Γ=9.3±0.9pmolcm-2) is found via electrografting method, (ii) graphene-modified-MTX has high affinity for ctDNA in a wide dynamic range of concentrations, and (iii) the nature of the interaction is of electrostatic and/or hydrogen bonding type, formed most probably between OH, NH and CO groups of MTX and different DNA functions. Finally, electrochemical impedance spectroscopy results approved the high affinity of the systems for 4T1 cancer cells.