Marcin Strawski

The targeting nanothin polyelectrolyte shells in system with immobilized bacterial cells for antitumor factor production

Development of anticancer treatment strategies is ongoing considering still inadequate efficiency of existing anticancer therapeutics. Moreover, the lack of therapeutic agents selectivity against the tumor cells requires further investigations into novel anticancer strategies. The use of pathogenic microorganisms producing an oncolytic agent may be an approach for apoptotic therapy in cancer treatment. The purpose of this study was to investigate the targeting efficiency of Bacillus subtilis bacterial cells coated with modified polyelectrolyte shells applied to protect the bacterial cells from potential host immune response as well as to enhance the tumor-targeting efficiency. The shells were modified with transferrin to increase affinity toward the target tumor cells. The impact of bacterial cells coated with unmodified or modified nanothin shells on human leukemia cells was evaluated in vitro. It was observed that the bacterial cells coated with modified shells with incorporated transferrin exhibited stronger lethal impact on leukemia cells as compared to bacterial cells with unmodified shell coating. Applied modified membrane conformation allowing for functioning of encapsulated microorganisms may find potential use in local antitumor treatment purposes.

Graphitic Carbon Nitride Doped with the S-Block Metals: Adsorbent for the Removal of Methyl Blue and Copper (II) Ions

The synthesis of graphitic carbon nitride (g-C3N4) doped with s-block metals is described. The materials were synthesized via thermal polycondensation of cyanamide and the appropriate metal chloride. The inclusion of the metal precursor strongly influenced the surface chemistry features as well as the textural, morphological, and structural properties of the g-C3N4. The doping of g-C3N4with s-block metals markedly enhanced its adsorption performance, which was studied during the removal of two model solutes (methyl blue and copper ions) from aqueous solutions. The maximum adsorption capacity for the organic dye was increased by 680 times after the doping process. The uptake of copper(II) increased ca. 30 times for the doped g-C3N4. The improvement of the adsorption performance is discussed in terms of the surface chemistry and textural features.

Stabilized nanosystem of nanocarriers with an immobilized biological factor for anti-tumor therapy

Objective The inadequate efficiency of existing therapeutic anti-cancer regiments and the increase in the multidrug resistance of cancer cells underscore the need to investigate novel anticancer strategies. The induction of apoptosis in tumors by cytotoxic agents produced by pathogenic microorganisms is an example of such an approach. Nevertheless, even the most effective drug should be delivered directly to targeted sites to reduce any negative impact on other cells. Accordingly, the stabilized nanosystem (SNS) for active agent delivery to cancer cells was designed for further application in local anti-tumor therapy. A product of genetically modified Escherichia coli, listeriolysin O (LLO), was immobilized within the polyelectrolyte membrane (poly(ethylenimine)|hyaluronic acid) shells of ‘LLO nanocarriers’ coupled with the stabilizing element of natural origin. Methods and results The impact of LLO was evaluated in human leukemia cell lines in vitro. Correspondingly, the influence of the SNS and its elements was assessed in vitro. The viability of targeted cells was evaluated by flow cytometry. Visualization of the system structure was performed using confocal microscopy. The membrane shell applied to the nanocarriers was analyzed using atomic force microscopy and Fourier transform infrared spectroscopy techniques. Furthermore, the presence of a polyelectrolyte layer on the nanocarrier surface and/or in the cell was confirmed by flow cytometry. Finally, the structural integrity of the SNS and the corresponding release of the fluorescent solute listeriolysin were investigated. Conclusion The construction of a stabilized system offers LLO release with a lethal impact on model eukaryotic cells. The applied platform design may be recommended for local anti-tumor treatment purposes.

Effect of structural factors on release profiles of camptothecin from block copolymer conjugates with high load of drug

The aim of the present work was the synthesis and study the kinetics and profiles of camptothecin (CPT) release form block co- and ter-polymer conjugates comprising polylactide (PLA) segments and CPT moieties, structurally diverse by degrees of branching, content of d-PLA units and poly(ethylene glycol) methyl ether methacrylate (PEGMA). Six PLA, non-toxic macroinitiators (MIs), terminated with α-bromoester were synthesized. MIs were subjected to polymerization of CPT methacrylic derivative (CPTMA) with PEGMA at various ratios. The average contents of CPT from elemental analysis, NMR and UV-GPC were approximate to each other. The number of CPT molecules and PEGMA units was in the range of 9-195 and 0-280 per conjugate, respectively. PEGMA units plasticized PLA causing increase of its crystallinity, whereas 7% and more of d-PLA caused material amorphous. PEGMA units decreased thermal stability of conjugates, however it compatibillized the separated phases of PLA and PCPTMA, based on AFM. In vitro release rate of CPT from linear PLA conjugates deposited on injection-molded PLA bars increased by introduction of PEGMA units with zero-order kinetics and Korsmeyer-Peppas model indicating the super case II transport. Branched conjugates revealed some burst release and then the release was rather of first-order-kinetics with respect to CPT with non-Fickian transport.