Encapsulation of amikacin into microparticles based on low-molecular-weight poly(lactic acid) and poly(lactic acid-co-polyethylene glycol)

The aim of this study was to fabricate novel microparticles (MPs) for efficient and long-term delivery of amikacin (AMI). The emulsification method proposed for encapsulating AMI employed low-molecular-weight poly(lactic acid) (PLA) and poly(lactic acid-co-polyethylene glycol) (PLA-PEG), both supplemented with poly(vinyl alcohol) (PVA). The diameters of the particles obtained were determined as less than 30 μm. Based on an in-vitro release study, it was proven that the MPs (both PLA/PVA- and PLA-PEG/PVA-based) demonstrated long-term AMI release (2 months), the kinetics of which adhered to the Korsmeyer-Peppas model. The loading efficiencies of AMI in the study were determined at the followings levels: 36.5 ± 1.5 μg/mg for the PLA-based MPs and 106 ± 32 μg/mg for the PLA-PEG-based MPs. These values were relatively high and draw parallels with studies published on the encapsulation of aminoglycosides. The MPs provided antimicrobial action against the Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae bacterial strains. The materials were also comprehensively characterized by the following methods: differential scanning calorimetry; gel permeation chromatography; scanning electron microscopy; Fourier transform infrared spectroscopy-attenuated total reflectance; energy-dispersive X-ray fluorescence; and Brunauer-Emmett-Teller surface area analysis. The findings of this study contribute toward discerning new means for conducting targeted therapy with polar, broad spectrum antibiotics. © 2021 The Authors. Published by American Chemical Society.Polish program for PhD students entitled "InterPhD2: The development of interdisciplinary and international PhD study programs" [POWR.03.02.00-00I002/16]; Ministry of Education, Youth and Sports of the Czech Republic, DKRVO grant [RP/CPS/2020/002]Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: RP/CPS/2020/00

Carboxymethylated and sulfated furcellaran from furcellaria lumbricalis and its immobilization on PLA scaffolds

This study involved the creation of highly porous PLA scaffolds through the porogen/leaching method, utilizing polyethylene glycol as a porogen with a 75% mass ratio. The outcome achieved a highly interconnected porous structure with a thickness of 25 μm. To activate the scaffold’s surface and improve its hydrophilicity, radiofrequency (RF) air plasma treatment was employed. Subsequently, furcellaran subjected to sulfation or carboxymethylation was deposited onto the RF plasma treated surfaces with the intention of improving bioactivity. Surface roughness and water wettability experienced enhancement following the surface modification. The incorporation of sulfate/carboxymethyl group (DS = 0.8; 0.3, respectively) is confirmed by elemental analysis and FT-IR. Successful functionalization of PLA scaffolds was validated by SEM and XPS analysis, showing changes in topography and increases in characteristic elements (N, S, Na) for sulfated (SF) and carboxymethylated (CMF). Cytocompatibility was evaluated by using mouse embryonic fibroblast cells (NIH/3T3).Ministry of Education, Youth, and Sports of the Czech Republi

Design and fabrication of electrospun PLA-based silica-modified composite nanofibers with antibacterial properties for perspective wound treatment

The aim of this study was to develop a novel amikacin (AMI) delivery system with prolonged release based on composite electrospun nanofibers of PLA supplemented with AMI-loaded Si nanoparticles of different morphology. The resultant materials were characterized in terms of their physical properties (scanning electron microscopy, Brunauer-Emmett-Teller analysis, thermogravimetric analysis, water contact angle). High-Performance Liquid Chromatography was used to determine the AMI content in the liquid fractions obtained from the release study. The results show that nanofibers of fumed silica exhibited an aggregated, highly porous structure, whereas nanofibers of mesoporous silica had a spherical morphology. Both silica nanoparticles had a significant effect on the hydrophilic properties of PLA nanofiber surfaces. The liquid fractions were investigated to gauge the encapsulation efficiency (EE) and loading efficiency (LE) of AMI, demonstrating 66% EE and 52% LE for nanofibers of fumed silica compared to nanofibers of mesoporous silica nanoparticles (52% EE and 12.7% LE). The antibacterial activity of the AMI-loaded nanofibers was determined by the Kirby-Bauer Method. These results demonstrated that the PLA-based silica nanofibers effectively enhanced the antibacterial properties against the Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae.TBU in Zlin, (IGA/CPS/2023/002); Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, (RP/CPS/2022/002, RP/CPS/2022/007)Ministry of Education, Youth and Sports of the Czech Republic [RP/CPS/2022/002, RP/CPS/2022/007]; Internal Grant Agency of TBU in Zlin [IGA/CPS/2023/002

Nanoparticle-based rifampicin delivery system development

The alkaline milieu of chronic wounds severely impairs the therapeutic effect of antibiotics, such as rifampicin; as such, the development of new drugs, or the smart delivery of existing drugs, is required. Herein, two innovative polyelectrolyte nanoparticles (PENs), composed of an amphiphilic chitosan core and a polycationic shell, were synthesized at alkaline pH, and in vitro performances were assessed by H-1 NMR, elemental analysis, FT-IR, XRD, DSC, DLS, SEM, TEM, UV/Vis spectrophotometry, and HPLC. According to the results, the nanostructures exhibited different morphologies but similar physicochemical properties and release profiles. It was also hypothesized that the simultaneous use of the nanosystem and an antioxidant could be therapeutically beneficial. Therefore, the simultaneous effects of ascorbic acid and PENs were evaluated on the release profile and degradation of rifampicin, in which the results confirmed their synergistic protective effect at pH 8.5, as opposed to pH 7.4. Overall, this study highlighted the benefits of nanoparticulate development in the presence of antioxidants, at alkaline pH, as an efficient approach for decreasing rifampicin degradation.Ministry of Education, Youth and Sport of the Czech Republic-DKRVO [RP/CPS/2020/005

New approaches and possibilities of arsenic removal from drinking water

Inorganic arsenic is in very small concentrations a common constituent of surface and groundwater. However, its increased concentration may pose a significant risk to human health in connection with its carcinogenicity (a proven human carcinogen). Therefore, it is necessary to address the reduction of its concentration in drinking water using the most efficient and financially undemanding techniques. The paper analyzes current and new trends in the field of removal of arsenic from drinking water. It focuses mainly on the use of adsorption-filtration techniques based on nanomaterial. This approach allows simultaneous sorption of the solubles and their removal by filtration. Partial results of the grant research focused on the design of the selective elimination process based on the application of nanostructured filtration and adsorption techniques are presented. The combination of the large nanofiber surface and sorption properties of the inorganic salt could be an effective method for removing arsenic. © SGEM 2019

Heterometallic 3d-4f {Co2Gd4} phosphonates: New members of the potential magnetic cooler family

Three new heterometallic phosphonate complexes with a novel 3d-4f metal core {Co2Gd4} were isolated. The reactions between CoCl2, GdCl3, ligand sodium salts, and 2,2′-bipyridine in methanol solution lead to new unexpected 3d-4f heterometallic complexes, [Na2CoIII2Gd4(L)6(bpy)2(OR)2]·nSolv (L = SAA3- (1), BSAA3- (2), and NAA3- (3); bpy = 2,2′-bipyridine; OR = OH and OMe; Solv = H2O and MeOH), composed of a rare case of two magnetically independent oxygen bridged Gd2O2 dinuclear units, which are separated by O-P-O bridges. According to the BVS calculations and measured magnetic properties, only CoIII ions are present in the obtained complexes. The magnetic properties of the compounds 1-3 were studied and the entropy changes for the designation of the magnetocaloric effect were calculated. The largest value for the magnetic entropy change -ΔSM of 20 J kg-1 K-1 for complex 1 has been found for Tav = 2.25 K and Hf = 5 T. © 2019 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.MEYS CR [LO1504, LM2015043, LQ1601

Eco-friendly whey/polysaccharide-based hydrogel with poly(lactic acid) for improvement of agricultural soil quality and plant growth

A set of renewable and biodegradable hydrogels based on acid whey and cellulose derivatives blended with poly (lactic acid) (PLA) were designed as eco-friendly biopolymeric material for sustainable agricultural applications. The physico-chemical properties of the hydrogel were evaluated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and rheological measurements. The effect of the whey/poly-saccharide/PLA hydrogel on soil quality improvement (water retention study, biodegradability, loading capacity and release of the fertilizers) and the growth pattern of Raphanus sativus and Phaseolus vulgaris has been also studied. The addition of PLA has been found to improve mechanical properties of the hydrogel. The introduction of 20% wt PLA extended decomposition time of hydrogels by 25% which makes the material more stable in the environment and maintaining the soil humidity for longer. The increasing the amount of PLA led to a rise in hydrogel viscosity brought about better entrapment efficiency of the fertilizers (86-92% for KNO3 and 87-96% for urea, resp.) compared to control (82% for KNO3 and 85% for urea, resp.). The novel hydrogels with swelling ratio of up to 500% showed potential as a sustainable water reservoir for plants improving water retention capacity of the soil by 30%.Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: RP/CPS/2020/002; Ministerstvo Zemědělství: QK1910392Ministry of Agriculture of the Czech Republic [QK1910392]; Ministry of Education, Youth and Sports of the Czech Republic [RP/CPS/2020/002

Unravelling the highly efficient synthesis of individual carbon nanodots from casein micelles and the origin of their competitive constant-blue-red wavelength shift luminescence mechanism for versatile applications

Synthesis of casein-derived carbon nanodots (CND) using a microwave-assisted approach, giving a high product yield (25%), is reported. Casein was used as a sustainable carbon source, and polyvinylpyrrolidone was used as a stabilizer for the nanodots. The size of the prepared amorphous CND corresponds to individual casein coils, which were only partially carbonized. They were obtained due to the disintegration of casein micelles and submicelles within the microwave-assisted solvothermal process. The resulting nanodots had bright photoluminescence, and their electronic structure and optical properties were investigated. A novel competitive model of their luminescence mechanism was introduced to explain a phenomenon beyond the standard models. The synthesized carbon nanodots were used as luminescent ink for anticounterfeit applications. A polymer matrix nanocomposite was prepared by dispersing the nanodots in a flexible and robust poly(styrene-ethylene-butylene-styrene) tri-block copolymer (SEBS) using the solution cast method. For the first time, the effect of CND on the luminescence and mechanical properties of the SEBS/CND self-supporting films was studied. The film was also studied as a phosphor for light-emitting diodes, with a unique experimental setup to avoid self-absorption, which results in low efficiency and eliminates the excess UV transmitted. Because of their high luminescence, photostability, and mechanical properties, these CND could be used as luminescent labels in the packaging and optoelectronics industries.Ministry of Education, Youth and Sports of the Czech Republic Program - DKRVO [RP/CPS/2022/007]; MEYS CR [LM2018110]RP/CPS/2022/007; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Central European Institute of Technology, CEITEC; Masarykova Univerzita, MU: LM201811

Carboxymethylated and Sulfated Furcellaran from <i>Furcellaria lumbricalis</i> and Its Immobilization on PLA Scaffolds

This study involved the creation of highly porous PLA scaffolds through the porogen/leaching method, utilizing polyethylene glycol as a porogen with a 75% mass ratio. The outcome achieved a highly interconnected porous structure with a thickness of 25 μm. To activate the scaffold’s surface and improve its hydrophilicity, radiofrequency (RF) air plasma treatment was employed. Subsequently, furcellaran subjected to sulfation or carboxymethylation was deposited onto the RF plasma treated surfaces with the intention of improving bioactivity. Surface roughness and water wettability experienced enhancement following the surface modification. The incorporation of sulfate/carboxymethyl group (DS = 0.8; 0.3, respectively) is confirmed by elemental analysis and FT-IR. Successful functionalization of PLA scaffolds was validated by SEM and XPS analysis, showing changes in topography and increases in characteristic elements (N, S, Na) for sulfated (SF) and carboxymethylated (CMF). Cytocompatibility was evaluated by using mouse embryonic fibroblast cells (NIH/3T3)

Investigation of arsenic removal from aqueous solution through selective sorption and nanofiber-based filters

Background: This research paper focuses on removing of arsenic from contaminated water via a nanofibrous polymeric microfiltration membrane, applied in prospective combination with an inorganic sorbent based on iron oxide hydroxide FeO(OH). Materials and methods: Nanofibrous materials were prepared by electrospinning from polyurethane selected by an adsorption test. The chemical composition (FTIR), morphology (SEM, porometry) and hydrophilicity (contact angle) of the prepared nanostructured material were characterized. The process of eliminating arsenic from the contaminated water was monitored by atomic absorption spectroscopy (AAS). The adsorption efficiency of the nanofibrous material and the combination with FeO(OH) was determined, the level of arsenic anchorage on the adsorption filter was assessed by a rinsing test and the selectivity of adsorption in arsenic contaminated mineral water was examined. Results: It was confirmed that the hydrophilic aromatic polyurethane of ester type PU918 is capable of capturing arsenic by complexation on nitrogen in its polymer chains. The maximum As removal efficiency was around 62 %. Arsenic was tightly anchored to the polymeric adsorbent. The adsorption process was sufficiently selective. Furthermore, it was found that the addition of even a small amount of FeO(OH) (0.5 g) to the nanofiber filter would increase the efficiency of As removal by 30 %. Conclusions: The presented results showed that an adsorption filter based on a polyurethane nanostructured membrane added with an inorganic adsorbent FeO(OH) is a suitable way for the elimination of arsenic from water. However, it is necessary to ensure perfect contact between the surface of the nanostructure and the filtered medium. © 2021, Springer Nature Switzerland AG.Technological Agency of the Czech Republic [TJ02000629]; Ministry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [LO1504, RP/CPS/2020/002]Technologická Agentura České Republiky: TJ02000629; Kementerian Pendidikan Malaysia, KP