Enhanced mechanical properties of a novel compatibilized recycled polyethylene terephthalate/polyamide 11 (rPET/PA11) blends

This research investigates various proportions of a compatibilizer, Joncryl®, in a newly developed blend of rPET/PA11 having 80 wt% rPET and 20 wt% PA11. The proposed blend exhibits unique and outstanding mechanical properties. A few of the significant benefits of carrying out this research work include recycling the highest amount of rPET, saving natural recourses, and encountering the environmental issues associated with the wastage of polymers. Five different proportions of Joncryl® (0, 1, 2, 3 and 4 phr) were introduced to the blend of rPET/PA11 through a twin-screw extruder and injection moulding machine. The blend interface studied by scanning electron microscope (SEM) indicated that Joncryl® boosted the chain extension. The results of tensile strength, Young’s modulus and flexural strength displayed the boost up in properties at all proportions; however, the properties at 2 phr of Joncryl® were unique and exclusive. The tensile strength of blend at 2 phr (Joncryl®) is remarkably increased from 26.8 to 46.24 MPa with a uniquely increased strain% from 3.56 to 196%. Young’s modulus is also significantly improved. The impact strength rose from 147.12 to 667.68 J/m

DEVELOPMENT OF BIOENGINEERING DESIGN OF ARTIFICIAL CORNEA BASED ON TISSUE MATRIX MADE OF SPIDROIN AND CULTIVATED CELLS OF EYE LIMBUS ZONE

Purpose. To study prerequisites for a development of artificial cornea bioengineered design based on recombinant spidroin tissue matrix by behavior evaluation of 2D (planar) and 3D cell (threedimensional) cultures on its surface.Material and methods. We studied epithelioid and stromal primary cell cultures (MSC-L) received from the limbal zone of post-mortem donor eyes. Cells were seeded on Petri dishes and on cavities of cultural trays (Corning, USA). To get spheroid structures the cells after the second passage underwent the centrifuge and were seeded on agarous trays then were cultivated in thermostatic chamber (Cell-IQ, Chip Man Technologies, Finland) under standard conditions (37° C, 5% CO2). Control over cell growth and morphology in trays was conducted under inverted microscope CKX41 (Olympus, Japan). To count the cell quantity and their viability the automatic cell counter Countess (Invitrogen, USA) was used, to analyze the surface proteins expression the flow cytofluorimetry was applied. For matrices colonization we used the 3rd passage MSC-L and 7-day spheroids of MSC-L origin. To evaluate 2D and 3D cell cultures growth on the surface of membranous matrices of recombinant spidroin, to estimate its non-toxicity and adhesiveness the immunohistochemistry, light time-lapse microscopy (Cell-IQ, Chip Man Technologies, Finland), laser scanning confocal microscopy (FluoView FV10i, Olympus, Japan) and raster electronic microscopy (CamScan, Japan) were incorporated.Results. Few hours after cell seeding there was active cells’ attachment to the substrate. Attached cells were characterized by rounded, oval or polygonal ordonnance. 24 hours later bipolar elongated cells and islets of migrating epithelioid cells appearance were observed. In the incubation process under gravity force the spheroids were accumulated predominantly in the central zone of the matrix, 2 hours later an active migration of spheroids surface zone epithelioid cells was registered on the membrane. After 24 hours of incubation all seeded on the surface of membranous matrix cells possessed a mesenchyme-like phenotype. Spheroids had an ability to merge limitlessly, later we observed a new microtissue formation with epithelioid cells on the surface and mesenchyme-like cells in the central area. Both solitary spheroids and merger-derived microtissue contained epithelial and mesenchymal components as well as regularly organized fibrils of extracellular matrix.Conclusions. According to aforementioned data the development of artificial cornea bioengineered cell-tissue constructions based on the technology of 3D cell spheroids cultivation derived from multipotent stem cells of the limbus and spidroin matrix presents a promising prospect requiring a further profound investigation

Клеточная нейропротекция как современный подход к лечению оптических нейропатий

Aim. To develop technology to create 3D-spheroid multipotent mesenchymal stem cells (MMSC) of limbal cadaveric human eyes, capable of safe and long-term secretion of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF).Materials and methods. MMSC were obtained by cultivation of limbal fragments, released from cadaveric donor human eye. Cultivation was carried out in DMEM/F12 medium, supplemented with L-glutamine, penicillin, streptomycin, amphotericin B, HEPES, insulin, dexamethasone and 10 vol.% FBS under standard conditions (5% СО2, 37 °C), medium change was performed every 3 days. To determine the phenotype of the received cell culture the method of immunophenotyping by marker proteins to MMSC (CD73, CD105, CD19, CD90, CD133) was used. Stimulation of neurotrophic factor secretion was performed via a twostep procedure. 3D-cell spheroids were created with the help of agarous plates for three groups of comparison, where group I was control group, spheroids of intact 2D-culture MMSK; group II – spheroids of previously induced 2D-culture MMSC; group III – spheroids of 2D-MMSC induced on the 1st day of cultivation. Cell cultures supernatants were selected in different periods for NGF and BDNF follow-up study by ELISA procedure.Results. Induction of 3D-spheroids of limbal MMSC promotes short-term increase of the level of BDNF and NGF, but further, the secretion of these factors significantly decreases. Induction leads to a change in the morphology of spheroids: loss of compactness and emergence of «fringed» (debris). Such changes indicate of frailty of received constructions. Spheroids from previously induced MMSC are capable of stable NTF secretion, but the level of secretion is much less as compared to the control group.Conclusion. 3D-cell culture of intact 2Dculture of limbal MMSC can be considered as cellular medication for a safe and long-term neuroprotection in optic neuropathy treatment.Цель. Разработать технологию создания 3D-сфероидов мультипотентных мезенхимальных стволовых клеток лимба кадаверных глаз человека, способных к длительной и достаточной секреции фактора роста нервов и нейротрофического фактора головного мозга.Материал и методы. Из кадаверных глаз человека (n = 8) выделялась зона лимба, содержащая наибольшее количество ММСК. Культивирование проводилось в среде: DMEM/F12 (1:1), L-глутамин, пенициллин, стрептомицин, амфотерицин В, HEPES, инсулин, дексаметазон, 10 об. % FBS при стандартных условиях (5% СО2, 37 °C), смена среды проводилась каждые 3 дня. Фенотип полученной культуры клеток изучали методом иммунофенотипирования с использованием набора маркеров к мембранным белкам (CD73, CD105, CD19, CD90, CD133). Стимуляцию секреции нейротрофических факторов проводили по двухэтапной методике с использованием неспецифических факторов активации. 3D-клеточные сфероиды создавали с использованием агарозных планшетов (3D Petri Dishes, Microtissue, США) для трех групп сравнения: I группа – контрольная, сфероиды из интактной 2D-культуры ММСК; II группа – сфероиды из индуцированной 2D-культуры ММСК; III группа – сфероиды из интактной 2D-культуры ММСК, индуцированные на 1-е сутки культивирования. Образцы консервационной среды замораживались при t –80 °С для дальнейшего исследования на содержание в них ФРН и БДНФ методом иммуноферментного анализа.Результаты. Индукция 3D-сфероидов ММСК лимба способствует значительному увеличению продукции ФРН и НФГМ, однако в дальнейшем наблюдается выраженное снижение секреции этих факторов. Проведение индукции приводит к изменению морфологии сфероидов: потере компактности, появлению «бахромчатости» (дебриса). Подобные изменения свидетельствуют о нежизнеспособности полученных конструкций. Сфероиды, созданные из индуцированных ММСК, способны к стабильной секреции НТФ, однако уровень секреции факторов значительно меньше по сравнению с группой контроля.Заключение. 3D-клеточные сфероиды, созданные из 2D-культуры интактных ММСК лимба, могут рассматриваться в качестве клеточного препарата для безопасной и длительной нейропротекции в лечении оптических нейропатий

Efect of maleated anhydride on mechanical properties of rice husk filler reinforced PLA Matrix Polymer Composite

Polylactic acid (PLA) formulated from corn starch has a bright potential to replace the non-renewable petroleum-based plastics. The combination of PLA and natural fbre has gained interest due to its unique performance, as reported in many researches and industries. Meanwhile, rice husk produced as the by-product of rice milling can be utilised, unless it is turned completely into waste. Therefore, in the present study, the rice husk powder (RHP) was used as a fller in the PLA, so to determine the infuence of the fller loading on the mechanical properties of the PLA composite. A coupling agent was selected for treatment from two options, i.e., maleic anhydride polypropylene (MAPP) and maleic anhydride polyethylene (MAPE), by applying the agents with various loading contents, such as 2, 4 and 6 wt%. The composite was fabricated by using the hot compression machine. Both the treated and untreated RHP–PLA composites were characterised via the tensile, fexural and impact strength tests. The increase in the RHP loading content led to the decrease in the tensile and fexural strengths. The applications of the coupling agents (MAPE and MAPP) did not improve the tensile and impact strengths, but the fexural strength was enhanced

ORIGINAL ARTICLE Ophthalmology Inpatient Consultation: Does it Make a Difference to Inpatient Management?

Ophthalmology consultation is one of the commonest requested services for inpatients in a tertiary hospital. A total of 290 ophthalmology consultation requests were received over a period of six months (average 12 consultation requests per week) and from these, 222 patients were examined. The patient demographics, the hospitalization data, type of consultations (screening, new problem, preexisting problem), reasons for consultations and the ophthalmology diagnosis were determined. Out of 290 consultation requests, internal medicine services requested the highest number (95, 32.8%); the commonest type of consultation was screening for eye diseases (161, 55.5%) and the most common reason for consultation was to rule out diabetic retinopathy (125, 43.1%). The top five ophthalmology diagnoses after examination were diabetic retinopathy (45, 20.3%), diabetic retinopathy ruled out (37, 16.6%), conjunctivitis (12, 5.4%), refractive error (11, 4.8%) and normal ocular examination (11, 4.9%). Inpatient ophthalmologic procedures were performed in 146 patients, the commonest of which was retinal laser photocoagulation. A total of 133 (59.9%) inpatients had a change in their management as a result of the ophthalmology consultation

Alginate based sustainable films and composites for packaging: a review

Alginate is an abundantly hydrophilic polysaccharide as much as 40 % of dry weight and commonly available in the cell wall of brown seaweed. The thickening, gel-forming and stabilizing properties of alginate makes it widely used biopolymer with a broader range of application including packaging. The superior valuable feature of alginate is the capability to yield a stable gel and insoluble polymer when they react through their carboxylate group with polyvalent metal cation especially Ca2+. Despite a wide range of applications, alginate has some drawbacks on the water resistivity due to hydrophilic nature, so its modifications with synthetic and natural polymers are carried out. This review article presents a different type of additives or polymer and their impact on the functional properties of alginate based composite films with special emphasis on packaging application

Laser-based technique for controlled damage of mesenchymal cell spheroids: a first step in studying reparation in vitro

Modern techniques of laser microsurgery of cell spheroids were used to develop a new simple reproducible model for studying repair and regeneration in vitro. Nanosecond laser pulses (wavelength 355 nm, frequency 100 Hz, pulse duration 2 ns) were applied to perform a microdissection of the outer and the inner zones of human bone marrow multipotent mesenchymal stromal cells (BM MMSC) spheroids. To achieve effective dissection and preservation of spheroid viability, the energy of laser pulses was optimized and adjusted in the range 7-9 μJ. After microdissection, the edges of the wound surface opened and the angular opening reached a value of more than 180°. The destruction of the initial spheroid structure was observed in the wound area, with surviving cells changing their shape into a round one. Partial restoration of a spheroid form took place in the first six hours. The complete structure restoration accompanying the reparative processes occurred gradually over seven days due to remodelling of surviving cells

Effects of date palm leaf fiber on the thermal and tensile properties of recycled ternary polyolefin blend composites

This work investigated the effects of date palm leaf fiber (DPLF) content on the thermal and tensile properties; and morphology of compatibilized polyolefin ternary blend. Recycled polyolefin ternary blend consisting of low density polyethylene (RLDPE), high density polyethylene (RHDPE) and polypropylene (RPP) were fabricated at different parts per hundred resin (phr) of DPLF. Maleic anhydride grafted polyethylene (MAPE) was used as compatibilizer to enhance the adhesion between filler and polymer matrix. The composites were prepared using melt extrusion and tests samples were produced via injection molding process. Thermal conductivity results showed that as much as 11 % reduction in thermal conductivity was achieved with the incorporation of 30 phr DPLF. Highest tensile strength was observed with the incorporation of 10 phr DPLF. The elongation at break was reduced with the addition of DPLF due to impediment of chain mobility by the fillers. Initial degradation temperature increased with the addition of DPLF. Hence, it is concluded that DPLF can be used to develop green and thermally insulating composites. It is hoped that the present results will stimulate further studies on the thermally insulative materials based on natural fibers reinforced polymer composites for applications in the building industries. , The Korean Fiber Society and Springer Science+Business Media B.V.Scopu

Inhaled Placental Mesenchymal Stromal Cell Secretome from Two- and Three-Dimensional Cell Cultures Promotes Survival and Regeneration in Acute Lung Injury Model in Mice

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is a common clinical problem, leading to significant morbidity and mortality, and no effective pharmacotherapy exists. The problem of ARDS causing mortality became more apparent during the COVID-19 pandemic. Biotherapeutic products containing multipotent mesenchymal stromal cell (MMSC) secretome may provide a new therapeutic paradigm for human healthcare due to their immunomodulating and regenerative abilities. The content and regenerative capacity of the secretome depends on cell origin and type of cultivation (two- or three-dimensional (2D/3D)). In this study, we investigated the proteomic profile of the secretome from 2D- and 3D-cultured placental MMSC and lung fibroblasts (LFBs) and the effect of inhalation of freeze-dried secretome on survival, lung inflammation, lung tissue regeneration, fibrin deposition in a lethal ALI model in mice. We found that three inhaled administrations of freeze-dried secretome from 2D- and 3D-cultured placental MMSC and LFB protected mice from death, restored the histological structure of damaged lungs, and decreased fibrin deposition. At the same time, 3D MMSC secretome exhibited a more pronounced trend in lung recovery than 2D MMSC and LFB-derived secretome in some measures. Taking together, these studies show that inhalation of cell secretome may also be considered as a potential therapy for the management of ARDS in patients suffering from severe pneumonia, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), however, their effectiveness requires further investigation