Chitosan and chitosan-grafted polylactic acid as a matrix for BSA encapsulation in a nanoparticle structure were prepared through a polyelectrolyte complexation method with dextran sulfate. Polylactic acid was synthetized via a polycondensation reaction using the non-metal-based initiator methanesulfonic acid and grafted to the chitosan backbone by a coupling reaction, with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide as the condensing agent. The effect of concentration of the polymer matrix utilized herein on particle diameter, ζ-potential, encapsulation efficiency, and the release kinetic of the model protein bovine serum albumin at differing pH levels was investigated. The influence of pH and ionic strength on the behavior of the nanoparticles prepared was also researched. Results showed that grafting polylactic acid to chitosan chains reduced the initial burst effect in the kinetics of BSA release from the structure of the nanoparticles. Furthermore, a rise in encapsulation efficiency of the bovine serum albumin and diminishment in nanoparticle diameter were observed due to chitosan modification. The results suggest that both polymers actually show appreciable encapsulation efficiency; and release rate of BSA. CS-g-PLA is more suitable than unmodified CS as a carrier for controlled protein delivery.

• Klíčová slova
• 2-Hydroxypropanoic acid (PubChem CID: 612), Bovine serum albumin, Bovine serum albumin (PubChem SID: 56312734), Chitosan, Chitosan (PubChem CID: 71853), Controlled drug delivery, Nanoparticles, Polylactic acid,
• MeSH
• chitosan chemie   MeSH
• koncentrace vodíkových iontů MeSH
• kyselina mléčná chemie   MeSH
• léky s prodlouženým účinkem MeSH
• molekulová hmotnost MeSH
• nanočástice chemie   MeSH
• polyestery MeSH
• polymery chemie   MeSH
• rozpustnost MeSH
• sérový albumin hovězí chemie   MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chitosan MeSH
• kyselina mléčná MeSH
• léky s prodlouženým účinkem MeSH
• poly(lactide) MeSH Prohlížeč
• polyestery MeSH
• polymery MeSH
• sérový albumin hovězí MeSH

The development of antibacterial materials has great importance in avoiding bacterial contamination and the risk of infection for implantable biomaterials. An antibacterial thin film coating on the surface via chemical bonding is a promising technique to keep native bulk material properties unchanged. However, most of the polymeric materials are chemically inert and highly hydrophobic, which makes chemical agent coating challenging Herein, immobilization of chlorhexidine, a broad-spectrum bactericidal cationic compound, onto the polylactic acid surface was performed in a multistep physicochemical method. Direct current plasma was used for surface functionalization, followed by carbodiimide chemistry to link the coupling reagents of N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC) and N-Hydroxysuccinimide (NHs) to create a free bonding site to anchor the chlorhexidine. Surface characterizations were performed by water contact angle test, X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The antibacterial activity was tested using Staphylococcus aureus and Escherichia coli. Finally, in vitro cytocompatibility of the samples was studied using primary mouse embryonic fibroblast cells. It was found that all samples were cytocompatible and the best antibacterial performance observed was the Chlorhexidine immobilized sample after NHs activation.

• Klíčová slova
• biomaterial associated infection, chlorhexidine, cytocompatibility, plasma treatment, polylactic acid,
• Publikační typ
• časopisecké články MeSH

The effect of 3D printing parameters by Fused Filament Fabrication (FFF) on the translucency of polylactic acid (PLA) parts was investigated. Six different printing parameters were studied: object orientation, layer height, nozzle temperature, fan speed, extrusion multiplier, and printing speed. The commercially available Plasty Mladeč PLA filament and the Original Prusa MK4 3D printer were used for the experiments. The translucency of the printed samples of 50 × 25 × 1 mm dimensions was measured using a luxmeter in an integrating sphere. A total of 32 sample combinations were created. Each sample was printed ten times. The results show that all investigated parameters significantly affect the optical properties of PLA parts. The best measured translucency values were obtained when printing in portrait mode, with a layer height of 0.30 mm, nozzle temperature of 240 °C, fan speed of 100%, 0.75 set extrusion multiplier, and a speed of 40 mm/s. ANOVA was used to statistically evaluate the effect of each parameter on translucency, and statistically significant differences were found between different combinations of parameters (p < 0.05). Scanning Electron Microscope (SEM) analysis provided detailed images of the surface structure of the printed samples, allowing for a better discussion of the microscopic properties affecting the translucency. The best print setting has an efficiency of 88% compared to the default setting of 65%. The ability of visible light to pass through the print (translucency) improved by 23%.

• Klíčová slova
• ANOVA, FFF, HSD test, extrusion multiplier, fan speed, integrating sphere, layer height, luxmeter, nozzle temperature, polylactic acid, slicer, translucence,
• Publikační typ
• časopisecké články MeSH

This paper deals with the study of the degradation of polylactic acid (PLA) material structures and biocomposite systems with a PLA matrix containing ground natural particulate waste fillers, buckwheat husks and egg shells. Waste fillers were used without difficult cleaning operations to describe the effect of the raw waste material on PLA. Biocomposites with raw waste materials are increasingly coming to the forefront in car interiors and packaging products. The prepared material systems were exposed to controlled climatic ageing simulating long-term solar radiation and cyclic outdoor conditions. The degradation of the biocomposite systems was evaluated via thermal (differential scanning calorimetry) and mechanical properties (tensile and flexural tests, Charpy impact toughness). In addition to evaluating the degradation of the material structures using standardized tests, the influence and effect of controlled climatic ageing was visually assessed using SEM images (electron microscopy) of the surfaces and fracture surfaces of the test specimens.

• Klíčová slova
• biocomposite, buckwheat husks, controlled climate ageing, degradation, egg shells, polylactic acid,
• Publikační typ
• časopisecké články MeSH

The effect of recycling on the thermo-mechanical and water absorption behavior of polypropylene (PP)/sisal fiber and polylactic acid (PLA)/sisal fiber composites were studied. The PP-based non-biodegradable composites and PLA-based biodegradable composites were recycled for four times. The effect of recycling was determined by examining the morphology, thermo-mechanical properties, and water absorption behavior and the obtained results were compared. The results showed that the incorporation of sisal fibers in the PP and PLA matrix enhances the tensile modulus and percentage crystallinity of the composites. The tensile strength and modulus of the sisal fiber reinforced PP composites were not affected with recycling. Even though the tensile properties of PLA and PLA/sisal fiber reinforced composites are superior to PP and PP/sisal fiber composites, the PLA-based composites show a dramatic decrease in tensile strength and modulus after the first recycling due to the degradation of the polymer. The thermal stability of the PP/sisal fiber composites was not affected by the repeated recycling process. On the other hand, the PLA-based composites with higher sisal fiber content show a bit lower thermal stability after recycling. The PP-based composites show fluctuations in percentage crystallinity with recycling. On the other hand, a remarkable increase in percentage crystallinity for PLA and PLA-based composites was observed with increasing recycling times. Water diffusion study divulges that the diffusion of water into the polymer composites was reduced with recycling, irrespective of the polymer matrix.

• Klíčová slova
• Polylactic acid, Polypropylene, Thermomechanical properties,
• MeSH
• polyestery MeSH
• polypropyleny * MeSH
• recyklace MeSH
• voda * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• poly(lactide) MeSH Prohlížeč
• polyestery MeSH
• polypropyleny * MeSH
• voda * MeSH

A critical lack of personal protective equipment has occurred during the COVID-19 pandemic. Polylactic acid (PLA), a polyester made from renewable natural resources, can be exploited for 3D printing of protective face masks using the Fused Deposition Modelling technique. Since the possible high porosity of this material raised questions regarding its suitability for protection against viruses, we have investigated its microstructure using scanning electron microscopy and aerosol generator and photometer certified as the test system according to the standards EN 143 and EN 149. Moreover, the efficiency of decontaminating PLA surfaces by conventional chemical disinfectants including 96% ethanol, 70% isopropanol, and a commercial disinfectant containing 0.85% sodium hypochlorite has been determined. We confirmed that the structure of PLA protective masks is compact and can be considered a sufficient barrier protection against particles of a size corresponding to microorganisms including viruses. Complete decontamination of PLA surfaces from externally applied Staphylococcus epidermidis, Escherichia coli, Candida albicans and SARS-CoV-2 was achieved using all disinfectants tested, and human adenovirus was completely inactivated by sodium hypochlorite-containing disinfectant. Natural contamination of PLA masks worn by test persons was decontaminated easily and efficiently by ethanol. No disinfectant caused major changes to the PLA surface properties, and the pore size did not change despite severe mechanical damage of the surface. Therefore, PLA may be regarded as a suitable material for 3D printing of protective masks during the current or future pandemic crises.

• Klíčová slova
• 3D printing, COVID-19, Disinfection, Ethanol, Human adenovirus, Polylactic acid, Protective masks, Reusable material, SARS-CoV-2, Virological testing,
• Publikační typ
• časopisecké články MeSH

This study is focussed on micro-encapsulation of essential oils in polylactic acid (PLA) and a poly(methyl methacrylate) (PMMA) matrix as well as blends of the same. Microspheres were prepared by the solvent evaporation technique and characterised by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR). The encapsulation efficiencies and release profiles of the essential oils were studied by gas chromatography mass spectrometry (GC-MS) and head-space solid-phase microextraction GC-MS, respectively. Furthermore, the microspheres were tested for antibacterial activity against both Gram-negative and Gram-positive bacterial strains. The results showed that the microspheres compositions (PLA/PMMA ratio) have significant effect on their characteristics. The process adopted for preparing the microspheres promoted formation of spherical particles at the sizes of 1.5-9.5 µm. The highest encapsulation efficiency of the prepared microspheres was observed in systems consisting of linalool (81.10 ± 10.0 wt. % for PLA system and 76.0 ± 3.3 wt. % for PMMA system). Confirmation was also made that the release rate of the microspheres was affected by the size of the same.

• Klíčová slova
• 4-allylanisole, Microspheres, antibacterial properties, essential oils, linalool, oil-in-water solvent evaporation technique, optical properties, poly(methyl methacrylate), polylactic acid, release study, trans-anethole,
• MeSH
• antibakteriální látky aplikace a dávkování   farmakologie   MeSH
• Bacteria účinky léků   MeSH
• bakteriální infekce farmakoterapie   MeSH
• lidé MeSH
• nosiče léků chemie   MeSH
• oleje prchavé aplikace a dávkování   farmakologie   MeSH
• polyestery chemie   MeSH
• polymethylmethakrylát chemie   MeSH
• příprava léků MeSH
• velikost částic MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• nosiče léků MeSH
• oleje prchavé MeSH
• poly(lactide) MeSH Prohlížeč
• polyestery MeSH
• polymethylmethakrylát MeSH

This study focused on material recycling of a biodegradable blend based on PLA and PHB for multiple applications of biodegradable polymeric material under real conditions. In this study, we investigated the effect of multiple processing of a biodegradable polymer blend under the trade name NONOILEN®, which was processed under laboratory as well as industrial conditions. In this article, we report on testing the effect of blending and multiple processing on thermomechanical stability, molecular characteristics, as well as thermophysical and mechanical properties of experimental- and industrial-type tested material suitable for FDM 3D technology. The results showed that the studied material degraded during blending and subsequently during multiple processing. Even after partial degradation, which was demonstrated by a decrease in average molecular weight and a decrease in complex viscosity in the process of multiple reprocessing, there was no significant change in the material's thermophysical properties, either in laboratory or industrial conditions. There was also no negative impact on the strength characteristics of multiple processed samples. The results of this work show that a biodegradable polymer blend based on PLA and PHB is a suitable candidate for material recycling even in industrial processing conditions. In addition, the results suggest that the biodegradable polymeric material NONOILEN® 3D 3056-2 is suitable for multiple uses in FDM technology.

• Klíčová slova
• 3D printing, material recycling, polyhydroxybutyrate, polylactic acid,
• Publikační typ
• časopisecké články MeSH

Recent complications on the use of polypropylene meshes for hernia repair has led to the development of meshes or films, which were based on resorbable polymers such as polycaprolactone (PCL), polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA). These materials are able to create suitable bioactive environment for the growth and development of cells. In this research, we mainly focused on the relations among structure, mechanical performance and biocompatiblity of PCL/PLA and PCL/PLGA and blends prepared by solution casting. The films were characterized regarding the chemical structure, morphology, physicochemical properties, cytotoxicity, biocompatibility and cell growth. All the films showed high tensile strength ranging from 9.5 to 11.8 MPa. SAXS showed that the lamellar stack structure typical for PCL was present even in the blend films while the morphological parameters of the stacks varied slightly with the content of PLGA or PLA in the blends. WAXS indicated preferential orientation of crystallites (and thus, also the lamellar stacks) in the blend films. In vitro studies revealed that PCL/PLGA films displayed better cell adhesion, spreading and proliferation than PCL/PLA and PCL films. Further the effect of blending on the degradation was investigated, to understand the significant variable within the process that could provide further control of cell adhesion. The results showed that the investigated blend films are promising materials for biomedical applications.

• Klíčová slova
• Biocompatibility, Mechanical properties, Nanoscale morphology, Polycaprolactone, Resorbable blends,
• MeSH
• difrakce rentgenového záření MeSH
• glykoly * MeSH
• kopolymer kyseliny glykolové a mléčné MeSH
• maloúhlový rozptyl MeSH
• polyestery MeSH
• vstřebatelné implantáty * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glykoly * MeSH
• kopolymer kyseliny glykolové a mléčné MeSH
• poly(lactide) MeSH Prohlížeč
• polycaprolactone MeSH Prohlížeč
• polyestery MeSH

OBJECTIVES: The recent use of antiretroviral drugs in people with HIV infection produced a drastic reduction in mortality and a remarkable improvement in the quality of life for these patients. However the aesthetic and psychological consequences that come from the reorganization of the adipose tissue induced by these drugs (facial wasting, buffalo hump) may reduce this state of wellbeing. METHODS: Our group, in cooperation with the 3rd Division of Infective Diseases of the University of Rome "La Sapienza", decided to evaluate the efficacy of polylactic acid (PLA) in combating these problems in HIV positive patients undergoing treatment with antiretroviral drugs in an evaluating study of 4 cases. The evaluation of the obtained results was performed by follow-up at one, three, six and twelve months from the first infiltration and considering the clinical evaluation, the photographical documentation and the patient's judgement. RESULTS: In all cases we obtained an improvement of the local condition with the restoration of a more booming aspect. The change was noted both within the family and the work environment. In the first three cases the results were considered as optimal by both the operators and the patients. In the fourth case the result was evaluated as discreet (a remarkable loss of weight of the patient in the months following the treatment should be taken into consideration). CONCLUSIONS: We think a new study with ultrasonography of dermal thickness before, during and after the treatment is necesary. This study will give a more reliable evaluation of the product efficacy.

• MeSH
• biokompatibilní materiály terapeutické užití   MeSH
• dospělí MeSH
• HIV infekce komplikace   farmakoterapie   MeSH
• kyselina mléčná terapeutické užití   MeSH
• lidé středního věku MeSH
• lidé MeSH
• obličej patologie   MeSH
• polyestery MeSH
• polymery terapeutické užití   MeSH
• syndrom lipodystrofie spojený s HIV farmakoterapie   MeSH
• vysoce aktivní antiretrovirová terapie škodlivé účinky   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• Názvy látek
• biokompatibilní materiály MeSH
• kyselina mléčná MeSH
• poly(lactide) MeSH Prohlížeč
• polyestery MeSH
• polymery MeSH