In vitro ispitivanje kontrolisanog otpuštanja antibiotika iz liposoma

Results of this study have shown significantly prolonged release of selected antibiotic from liposome dispersion as compared to free antibiotic solution of the same initial concentration. Two models of non-steady one-dimensional diffusion were successfully applied to the experimental data and the antibiotic diffusion coefficients were estimated. In addition, the mass transfer resistance of the membrane was shown to be insignificant confirming the suitability of the applied experimental system. Since liposomes are known as systems with slower drug release, then, when it comes to their incorporation in the final form of a preparation for further experiments in vivo, the system of choice would be liposomes with an encapsulated antibiotic drug. The established experimental system could be extended to other liposome formulations with respect to the release rate of the active components.Rezultati su pokazali značajan efekat produženog oslobađanja odabranog antibiotika iz lipidnih vezikula u membranskom sistemu sa cilindričnim modulom (namenski dizajniran u cilju mimike sistema primene topičnog preparata na koži) u poređenju sa rastvorom leka iste inicijalne koncentracije koji je podvrgnut istim eksperimentalnim uslovima. Dva modela nestacionarne, jednodimenzione difuzije primenjena su za predviđanje brzine oslobađanja leka iz lipidnih vezikula u cilindričnom membranskom modulu. Oba modela su pokazala dobro slaganje sa eksperimentalnim rezultatima i predskazala približno pedeset puta sporije otpuštanje iz lipidnih vezikula u poređenju sa čistim rastvorom leka. Osim toga, rezultati matematičkog modelovanja su pokazali da celulozno-acetatna membrana ima zanemarljiv uticaj na ukupnu brzinu oslobađanja leka. Ovakav rezultat potvrdio je pogodnost primenjenog eksperimentalnog sistema za ispitivanje kinetike otpuštanja odabranog antibiotika iz lipidnih vezikula.Kako se pokazalo da je otpuštanje leka iz disperzije lipidnih vezikula sporije u poređenju sa čistim rastvorom antibiotika, ovakav sistem nosača sa inkapsuliranim antibiotskim agensom ima prednost kada je u pitanju njegovo ugrađivanje u finalni oblik topičnog preparata za dalja ispitivanja in vivo. Odabrani eksperimentalni sistem se može primeniti i na druge formulacije na bazi lipidnih vezikula, za ispitivanje kinetike otpuštanja inkapsuliranih aktivnih supstanci. Na taj način bi se mogla uspostaviti relevantna metoda za in vitro karakterizaciju i poređenje različitih sistema nosača aktivnih komponenti

Comparative studies on osmosis based encapsulation of sodium diclofenac in porcine and outdated human erythrocyte ghosts

The objective of our study was to develop controlled drug delivery system based on erythrocyte ghosts for amphiphilic compound sodium diclofenac considering the differences between erythrocytes derived from two readily available materials - porcine slaughterhouse and outdated transfusion human blood. Starting erythrocytes, empty erythrocyte ghosts and diclofenac loaded ghosts were compared in terms of the encapsulation efficiency, drug releasing profiles, size distribution, surface charge, conductivity, surface roughness and morphology. The encapsulation of sodium diclofenac was performed by an osmosis based process - gradual hemolysis. During this process sodium diclofenac exerted mild and delayed antihemolytic effect and increased potassium efflux in porcine but not in outdated human erythrocytes. FTIR spectra revealed lack of any membrane lipid disorder and chemical reaction with sodium diclofenac in encapsulated ghosts. Outdated human erythrocyte ghosts with detected nanoscale damages and reduced ability to shrink had encapsulation efficiency of only 8%. On the other hand, porcine erythrocyte ghosts had encapsulation efficiency of 37% and relatively slow drug release rate. More preserved structure and functional properties of porcine erythrocytes related to their superior encapsulation and release performances, define them as more appropriate for the usage in sodium diclofenac encapsulation process

Biomaterijali

Početak XXI veka nesumnjivo je obeležen interdisciplinarnim i multidisciplinarnim naporima istraživača u različitim oblastima nauke. Jedna od najizrazitijih tendencija ovog tipa uočava se u biomedicinskim istraživanjima, gde se združuju napori lekara, biologa, genetičara i biohemičara, s jedne strane, i biofizičara i inženjera, s druge strane – sa ciljem dubljeg razumevanja zdravlja i bolesti, i primene ovih saznanja u biomedicinskoj praksi, tako važnoj u svakodnevnom životu ljudi.Kao rezultat ovih svetskih trendova, u Srbiji već više godina na nekoliko fakulteta postoji nastava iz oblasti biomedicinskog inženjerstva, sa ciljem da osposobi inženjere ovih usmerenja za multidisciplinarno povezivanje znanja iz oblasti tehnike sa biomedicinskim znanjima. Jedan od bazičnih predmeta ovih usmerenja jesu Biomaterijali, kojima je i posvećen naš udžbenik, čiji je cilj da predstavi pregled teorije i prakse biomaterijala u biomedicinskoj nauci.Nauka o biomaterijalima je nesumnjivo najmultidisciplinarnija od svih nauka, jer zahteva ovladavanje znanjima iz mnogih oblasti nauke i tehnologije, inženjerstva i medicine, kako bi naučnici iz oblasti biomaterijala mogli da se uhvate u koštac sa ovom profesijom. Zato posle uvodnog dela, udžbenik iz Biomaterijala sadrži četiri celine: (I) Osnovni biomedicinski koncepti i reakcije organizma na biomaterijale, (II) Struktura, fizičko-mehanička karakterizacija i modeliranje biomaterijala i tkiva, (III) Savremeni biomaterijali i tehnologije, (IV) Perspektive biomaterijala i tehnologija, iza kojih slede Zadaci sa rešenjima, Ispitna test pitanja i Ispitna teorijska pitanja, koji pomažu studentima da lakše savladaju veoma obimno i kompleksno gradivo. Na kraju svakog poglavlja data su pitanja za rekapitulaciju, kao i spisak dopunske literature za opcionu detaljniju obradu pojedinih oblasti.Grupa od dvadeset četiri profesionalca sa univerziteta i naučnih instituta, pod okriljem Instituta tehničkih nauka Srpske akademije nauka i umetnosti, Beograd, i Društva za istraživanje materijala Srbije (MRS Srbija) doprinela je pisanju ovog kapitalnog udžbenika o biomaterijalima, prvog do sada na srpskom jeziku. Mada uključivanje veće grupe autora nužno dovodi do stilske neujednačenosti, ipak je oblast biomaterijala toliko multidisciplinarna da je ovakav pristup bio neophodan, kako uostalom pokazuju slična svetska iskustva sa uključivanjem i preko pedeset autora. Ipak urednici su se potrudili da koliko je to moguće stilski i pedagoški ujednače udžbenik, kako bi bio korisna literatura za sve studente diplomskih, master i doktorskih studija iz biomedicinskog inženjerstva u Srbiji i okruženju

Biomaterijali

Početak XXI veka nesumnjivo je obeležen interdisciplinarnim i multidisciplinarnim naporima istraživača u različitim oblastima nauke. Jedna od najizrazitijih tendencija ovog tipa uočava se u biomedicinskim istraživanjima, gde se združuju napori lekara, biologa, genetičara i biohemičara, s jedne strane, i biofizičara i inženjera, s druge strane – sa ciljem dubljeg razumevanja zdravlja i bolesti, i primene ovih saznanja u biomedicinskoj praksi, tako važnoj u svakodnevnom životu ljudi.Kao rezultat ovih svetskih trendova, u Srbiji već više godina na nekoliko fakulteta postoji nastava iz oblasti biomedicinskog inženjerstva, sa ciljem da osposobi inženjere ovih usmerenja za multidisciplinarno povezivanje znanja iz oblasti tehnike sa biomedicinskim znanjima. Jedan od bazičnih predmeta ovih usmerenja jesu Biomaterijali, kojima je i posvećen naš udžbenik, čiji je cilj da predstavi pregled teorije i prakse biomaterijala u biomedicinskoj nauci.Nauka o biomaterijalima je nesumnjivo najmultidisciplinarnija od svih nauka, jer zahteva ovladavanje znanjima iz mnogih oblasti nauke i tehnologije, inženjerstva i medicine, kako bi naučnici iz oblasti biomaterijala mogli da se uhvate u koštac sa ovom profesijom. Zato posle uvodnog dela, udžbenik iz Biomaterijala sadrži četiri celine: (I) Osnovni biomedicinski koncepti i reakcije organizma na biomaterijale, (II) Struktura, fizičko-mehanička karakterizacija i modeliranje biomaterijala i tkiva, (III) Savremeni biomaterijali i tehnologije, (IV) Perspektive biomaterijala i tehnologija, iza kojih slede Zadaci sa rešenjima, Ispitna test pitanja i Ispitna teorijska pitanja, koji pomažu studentima da lakše savladaju veoma obimno i kompleksno gradivo. Na kraju svakog poglavlja data su pitanja za rekapitulaciju, kao i spisak dopunske literature za opcionu detaljniju obradu pojedinih oblasti.Grupa od dvadeset četiri profesionalca sa univerziteta i naučnih instituta, pod okriljem Instituta tehničkih nauka Srpske akademije nauka i umetnosti, Beograd, i Društva za istraživanje materijala Srbije (MRS Srbija) doprinela je pisanju ovog kapitalnog udžbenika o biomaterijalima, prvog do sada na srpskom jeziku. Mada uključivanje veće grupe autora nužno dovodi do stilske neujednačenosti, ipak je oblast biomaterijala toliko multidisciplinarna da je ovakav pristup bio neophodan, kako uostalom pokazuju slična svetska iskustva sa uključivanjem i preko pedeset autora. Ipak urednici su se potrudili da koliko je to moguće stilski i pedagoški ujednače udžbenik, kako bi bio korisna literatura za sve studente diplomskih, master i doktorskih studija iz biomedicinskog inženjerstva u Srbiji i okruženju

Catalyzing Transcriptomics Research in Cardiovascular Disease : The CardioRNA COST Action CA17129

Cardiovascular disease (CVD) remains the leading cause of death worldwide and, despite continuous advances, better diagnostic and prognostic tools, as well as therapy, are needed. The human transcriptome, which is the set of all RNA produced in a cell, is much more complex than previously thought and the lack of dialogue between researchers and industrials and consensus on guidelines to generate data make it harder to compare and reproduce results. This European Cooperation in Science and Technology (COST) Action aims to accelerate the understanding of transcriptomics in CVD and further the translation of experimental data into usable applications to improve personalized medicine in this field by creating an interdisciplinary network. It aims to provide opportunities for collaboration between stakeholders from complementary backgrounds, allowing the functions of different RNAs and their interactions to be more rapidly deciphered in the cardiovascular context for translation into the clinic, thus fostering personalized medicine and meeting a current public health challenge. Thus, this Action will advance studies on cardiovascular transcriptomics, generate innovative projects, and consolidate the leadership of European research groups in the field.COST (European Cooperation in Science and Technology) is a funding organization for research and innovation networks (www.cost.eu)

Alginate microbeads as potential support for cultivation of bone marrow stromal cells

Alginate is currently being employed and explored for a broad range of biomedical and biotechnology applications, due to its biodegradability and simple procedure for cell immobilization. However, cell immobilization was mostly aimed for immunoisolatory and biochemical processing applications and far less is known about potentials of alginate as a substrate for tissue formation. In the present work, isolation, immobilization and cultivation procedures of murine bone marrow stromal cells (BMSC) were studied and standardized in order to establish the alginate-bioreactor culture system for chondrogenic and/or hematopoiesis-supportive tissue progression. Two techniques for cell immobilization based on alginate were investigated: entrapment within gel matrix using electrostatic droplet generation and simple cell adsorption onto gel surfaces. Alginate gels in forms of microbeads and discs with immobilized culture expanded BMSC were cultivated for up to 30 days and analyzed for surface properties, cell concentration, viability, and differentiation

Liposomes with alpha-tocopherol membrane

Liposomes, closed spherical structures formed by phospholipid bilayers, have been recognized as a controlled drug delivery system. We have studied the preparation and biocompatibility of liposomes based on soya phospholipids encapsulated with alpha-tocopherol. The binding efficiency of alpha-tocopherol was analysed by comparing two methods for liposome preparation: a) dry film (DFM) and b) solvent infusion method (SIM). The degree of encapsulation achieved (88-93%) suggested a high affinity of alpha-tocopherol for liposome membrane binding. The initial concentration of alpha-tocopherol had a significant effect on the degree of encapsulation, while the effect of method used was less pronounced. In general, a higher degree of encapsulation was achieved with smaller liposome size fractions. Based on an experimentally obtained size distribution function, it can be concluded that if smaller liposomes are used, SIM seems to be more efficient due to the higher content of smaller vesicles. The in vivo application of the liposomes to CBA mice confirmed the biocompatibility and nontoxicity of such preparations. The analysis of hematological parameters in peripheral blood (determination of mature blood cells with differential count) revealed that liposomes did not express cytotoxic effects on any of the parameters tested

Rheological quantification of liposomes aggregation

Aim. The aggregation of phospholipid vesicles (liposomes) in water is analyzed experimentally and theoretically and compared with the well-examined alumina dispersions. The steady-state aggregation followed rheologically for various volume fractions of particles and shear rates. Methods. A micro-rheological model of aggregating dispersions is proposed in which the apparent viscosity is estimated as the sum of hydrodynamic and structural parts, which are correlated with system structural ordering. Langevin equation is used to describe the dynamics of evolution of steady-states of liposome systems in phase space, for various shear rates. Results. These results established a link between the local dynamics of liposome dispersions and their flow behavior. Conclusion. Aggregates become more compact and embedded higher volume of fluid when shear rate increases. Hydrodynamic part of viscosity increases, while structural part of viscosity decreases with shear rate. Calculated value of bond energy between liposomes corresponds to hydrogen bond energy