Effects of process parameters on structure and properties of melt-blown poly(lactic acid) nonwovens for skin regeneration

Skin regeneration requires a three-dimensional (3D) scaffold for cell adhesion, growth and proliferation. A type of the scaffold offering a 3D structure is a nonwoven material produced via a melt-blown technique. Process parameters of this technique can be adapted to improve the cellular response. Polylactic acid (PLA) was used to produce a nonwoven scaffold by a melt-blown technique. The key process parameters, i.e., the head and air temperature, were changed in the range from 180–270 °C to obtain eight different materials (MB1–MB8). The relationships between the process parameters, morphology, porosity, thermal properties and the cellular response were explored in this study. The mean fiber diameters ranged from 3 to 120 µm. The average material roughness values were between 47 and 160 µm, whereas the pore diameters ranged from 5 to 400 µm. The calorimetry thermograms revealed a correlation between the temperature parameters and crystallization. The response of keratinocytes and macrophages exhibited a higher cell viability on thicker fibers. The cell-scaffold interaction was observed via SEM after 7 days. This result proved that the features of melt-blown nonwoven scaffolds depended on the processing parameters, such as head temperature and air temperature. Thanks to examinations, the most suitable scaffolds for skin tissue regeneration were selected

Newly crosslinked chitosan- and chitosan-pectin-based hydrogels with high antioxidant and potential anticancer activity

Monoaldehydes, due to natural origin and therapeutic activity, have attracted great attention for their ability to crosslink chitosan hydrogels for biomedical applications. However, most studies have focused on single-component hydrogels. In this work, chitosan-based hydrogels, crosslinked for the first time with 2,3,4-trihydroxybenzaldehyde (THBA), were modified with pectin (PC), bioactive glass (BG), and rosmarinic acid (RA). All of these were not only involved in the crosslinking, but also modulated properties or imparted completely new ones. THBA functioned as a crosslinker, resulting in improved mechanical properties, high swelling capacity and delayed degradation and also imparted high antioxidant activity and antiproliferative effect on cancer cells without cytotoxicity for normal cells. Hydrogels containing PC showed enhanced mechanical strength, while the combination with BG gave improved stability in PBS. All hydrogels modified with BG exhibited the ability to mineralise in SBF. The addition of RA enhanced antioxidant and anticancer activities and promoting the mineralisation process

Modification of heat-induced whey protein isolate hydrogel with highly bioactive glass particles results in promising biomaterial for bone tissue engineering

This study deals with the design and comprehensive evaluation of novel hydrogels based on whey protein isolate (WPI) for tissue regeneration. So far, WPI has been considered mainly as a food industry by-product and there are very few reports on the application of WPI in tissue engineering (TE). In this work, WPI-based hydrogels were modified with bioactive glass (BG), which is commonly used as a bone substitute material. Ready-to-use, sterile hydrogels were produced by a simple technique, namely heat-induced gelation. Two different concentrations (10 and 20% w/w) of sol–gel-derived BG particles of two different sizes (2.5 and <45 µm) were compared. µCT analysis showed that hydrogels were highly porous with almost 100% pore interconnectivity. BG particles were generally homogenously distributed in the hydrogel matrix, affecting pore size, and reducing material porosity. Thermal analysis showed that the presence of BG particles in WPI matrix reduced water content in hydrogels and improved their thermal stability. BG particles decreased enzymatic degradation of the materials. The materials underwent mineralization in simulated biological fluids (PBS and SBF) and possessed high radical scavenging capacity. In vitro tests indicated that hydrogels were cytocompatible and supported MG-63 osteoblastic cell functions

Dual FRET assay for detecting receptor protein interaction with DNA

We present here a new assay that is based on the idea of the molecular beacon. This assay makes it possible to investigate two proteins interacting with DNA at two binding sites that are close to each other. The effectiveness of the test depends on the exclusive binding of three DNA fragments in the presence of two proteins, and the monitoring of the process depends upon observing the quenching of two independent fluorescence donors. As a model we used the components of the heterodimeric ecdysteroid receptor proteins ultraspiracle (Usp) and ecdysone receptor (EcR) from Drosophila melanogaster and a response element from the promoter of the hsp27 gene. The response element consists of two binding sites (half-sites) for the DNA binding domains (DBDs). We have shown that protein–protein interactions mediate cooperative binding of the ecdysteroid receptor DBDs to a hsp27pal response element. The analysis of the microscopic dissociation constants obtained with the DMB led to the conclusion that there was increased affinity of UspDBD to the 5′ half-site in the presence of EcRDBD when the 3′ half-site was occupied, and increased affinity of EcRDBD to the 3′ half-site when the 5′ half-site was occupied

Mechanical Properties of Polylactide Admixed with Carbon Nanotubes or Graphene Nanopowder

The aim of this work was to verify the material properties of polylactic acid (PLA) with an addition of carbon nanotubes (CNTs) or graphene nanopowder (GNP). The pure polylactide and admixed polylactide samples were subjected to chemical–physical tests to determine their stiffness and strength parameters. The tensile and impact tests were performed on samples without UV (ultraviolet) treatment and after UV treatment, in a physiological saline solution. The investigations were composed of two stages. The first one was related to the examination of the properties of pure polylactide, denoted as the following: 3001D, 4032D, and 4043D. The second stage was based on an analysis of the properties of PLA 4032D with an admixture of GNP or CNTs, at 0.1 wt.% and 0.5 wt.%. By comparing the strength and the stiffness of pure samples with samples with the considered admixtures, an essential increase was not observed. However, it is stated that the presence of GNP and CNTs in the samples positively influenced the resistance of the materials to the ageing process

Wpływ samoregenerującej się osnowy poliuretanowej na właściwości kompozytu z włóknem węglowym /

Promotor: Stanisław Błażewicz, Kinga Pielichowska.Niepublikowana praca doktorska.Praca doktorska. Akademia Górniczo-Hutnicza im. Stanisława Staszica. Wydział Inżynierii Materiałowej i Ceramiki. Katedra Biomateriałów, 2015.Bibliogr. k. 179-186.Materiały kompozytowe, kompozyty wzmacniane włóknami, włókna węglowe, prekursory, proces, budowa włókna i jego właściwości mechaniczne, perspektywy rozwoju technologii włókien węglowych, kompozyty o osnowach polimerowych, poliuretany, budowa PU, podstawowe surowce służące do syntezy PU, diizocyjaniany, poliole, przedłużacze łańcucha, katalizatory, synteza poliuretanów, kompozyty PU/CF, nanorurki węglowe, wzmacnianie matrycy PU nanorurkami węglowymi, synteza nanokompozytów PU/CNT, materiały samoregenerujące wady, ogólna charakterystyka samoregenerujących się materiałów, samoregeneracja zewnętrzna, materiały samoregenerujące wady zawierające mikrokapilary, puste rurki włókno szklane, trójwymiarowy system kapilar w materiale, materiały samoregenerujące wady z mikrokapsułkami, materiały z wrodzoną samoregeneracją, samoregeneracja poprzez oddziaływania fizyczne, samoregeneracja poprzez oddziaływania chemiczne, samoregenerujące się poliuretany, materiały do wytworzenia PU, składniki matrycy PU, faza modyfikująca, CNT, włókno węglowe, synteza PU w obecności CNT, obliczanie receptury syntezy PU, otrzymywanie próbek kompozytów zawierających nanorurki węglowe i włókno węglowe, rodzaje otrzymanych próbek, badania właściwości mechanicznych, badania właściwości termicznych, badania TG/DTA, skaningowa kalorymetria różnicowa DSC, badania TOPEM, badania przewodnictwa cieplnego, badania SEM, badania metodą spektroskopii w podczerwieni, badania metodą spektroskopii Ramana, badania stopnia samoregeneracji, badania kompozytów PU/CNT i PU/CNT-OH, badania właściwości mechanicznych kompozytów, badania właściwości mechanicznych kompozytów PU/CNT, badania właściwości mechanicznych kompozytów PU/CNT-OH, badania TG, badania termiczne kompozytów PU/CNT, badania termiczne kompozytów PU/CNT-OH, badania DSC, badania TOPEM DSC, badania przewodnictwa cieplnego, badania przewodnictwa cieplnego kompozytów z CNT, badania przewodnictwa cieplnego kompozytów z CNT-OH, badania metodą spektroskopii w podczerwieni, badania metodą spektroskopii Ramana, badania metodą spektroskopii Ramana próbek z CNT, badania metodą spektroskopii Ramana próbek z CNT-OH, mikroskopia SEM, wyniki badań kompozytów PU/CNT-OH/CF, badania właściwości mechanicznych, badania termograwimetryczne, badania przewodnictwa cieplnego, badania metodą spektroskopii w podczerwieni, badanie metodą spektroskopii Ramana, badania mikrostruktury, wyniki badań właściwości samoregenerujących kompozytów PU/CNT-OH, badania właściwości mechanicznych, badania przewodnictwa cieplnego, badania właściwości samoregenerujących się kompozytów PU/CNT-OH/CF, obserwacje mikroskopow

Validation of MS/MS method for simultaneous measurement of meropenem and linezolid in cerebrospinal fluid.

Zakażenia w ośrodkowym układzie nerwowym są jedną z najczęstszych przyczyn zachorowalności i śmiertelności u dzieci. W grupie noworodków i niemowląt śmiertelność w przypadku zakażeń inwazyjnych (w tym OUN) sięga aż 50%. Z tego powodu uważa się, że metody pozwalające na optymalizację leczenia przeciwdrobnoustrojowego są kluczowe dla postępowania terapeutycznego. Jedną z możliwości optymalizacji leczenia jest terapia monitorowania stężenia leku.Dla wielu antybiotyków nowej generacji nie ma metod komercyjnych, które umożliwiają oznaczenia w płynie mózgowo-rdzeniowym. Opracowanie lub modyfikacja dostępnych metod przez laboratoria wymaga ich walidacji. Celem pracy była walidacja metody do jednoczesnego oznaczania meropenemu (Mer) i linezolidu (Lin) w PMR z wykorzystaniem LC-MS/MS. Do oceny parametrów walidacyjnych wykorzystano syntetyczny i natywny płyn mózgowo-rdzeniowy. Uzyskano następujące wyniki dla walidowanej metody: zakres liniowości 0.1 - 50 μg/ml, LOD dla Mer i Lin 0.02 μg/ml, LOQ dla Mer 0.07 μg/ml oraz 0.05 μg/ml dla Lin. Powtarzalność metody (CV) wynosiła 5.18% dla Mer oraz 5.53% dla Lin, a odtwarzalność 6.47% dla Mer oraz 5.62% dla Lin. Odzysk dla Mer wynosił 88.00 - 114.53% z syntetycznego PMR oraz 86.67 - 113.86% z natywnego PMR. Dla Lin były to wartości 85.33 - 114.57% z syntetycznego PMR oraz 88.00 - 114.87% z natywnego PMR. Próbki mogą być rozcieńczane solą fizjologiczną maksymalnie ośmiokrotnie. Mer i Lin były stabilne 24 h w temp. 4oC oraz 30 dni w temp. -80oC. Na podstawie uzyskanych wyników stwierdzono, że walidowana metoda LC-MS/MS do równoczesnego oznaczania Mer i Lin może być stosowana do oznaczania tych leków w płynie mózgowo-rdzeniowym.Central nervous system infections are one of the most common cause of morbidity and mortality among children. In the group of newborns and infants mortality rate achieves 50% for invasive infections (including CNS). That is the reason, why method which can optimize the antimicrobial treatment is so important in therapeutic management. The therapeutic drug monitoring can be one of these methods. For many antibiotics of new generation there is no commercial method to measure them in cerebrospinal fluid (CSF). Validation is necessary when laboratory creates or modifies available method. The aim of the study was to validate LC-MS/MS method for simultaneous measurement of meropenem (Mer) and linezolid (Lin) in CSF. Synthetic and native CSF were used to check validation parameters. The calibration curve concentration range was 0.1 - 50μg/ml, LOD was 0.02μg/ml for Mer and Lin, LOQ was 0.07μg/ml for Mer and 0.05μg/ml for Lin. Intraday precision was 5.18% for Mer and 5.53% for Lin, interday precision was 6.47% for Mer and 5.62% for Lin. Recovery for Mer was ranged 88.00 - 114.53% from synthetic CSF, 86.67 - 113.86% from native CSF, for Lin 85.33 - 114.57% from synthetic CSF, 88.00 - 114.87% from native CSF. Sample can be dilluted by saline maximum eight times. Mer and Lin show stability for 24 h in temperature 4oC, 30 days in temperature -80oC. Based on the research outcome, it was evidenced that the validated method of simultaneous measurement of Mer and Lin can be utilized to measure those drugs in CSF

Biocomposites based on a balsa wood core containing intermediate layers made of coconut and sisal

Sandwich-type composite materials of various geometries were obtained, in which the inner layer was a laminate of glass fabric, and the core consisted of natural materials: balsa wood, coconut and sisal fibres. The materials were tested to determine the type of cracking process under static and dynamic stress conditions (impact strength). The best results were obtained for hybrid balsa/glass fabric composites with a spacer made of sisal mat. This type of system allows a controlled cracking process, which is a consequence of a different stress distribution. The research shows that the combination of different materials in a single composite, depending on their volume fraction, density and layering geometry, opens the way for use in technical constructions, especially where high specific strength is required. The work contains valuable results of research on sandwich materials, their behaviour under load, their modification, and their impact on the transfer of dynamic and static stresses. For the first time, a composition was tested containing a balsa tree core with transient elastic layers made of natural cellulose fibres