Thermoresponsive poly[oligo(ethylene glycol) methacrylate]s and their bioconjugates – synthesis and solution behavior

Growing interest for polymers containing oligoethylene side groups was observed within last years. Amongst these polymers the poly[oligo(ethylene glycol) methacrylate]s (POEGMAs) became most important. These polymers are biocompatible. Many of these polymers are thermoresponsive, when dissolved in water or physiological media, exhibit a narrow phase transition range and show only a small hysteresis. This review describes the synthesis and self-organization of homo- and copolymers of POEGMAs of different macromolecular topology. Data about the synthesis of thermoresponsive conjugates of POEGMAs with biologically active species and the possibility to use such conjugates for the synthesis of nanocarriers are discussed.W ciągu ostatnich kilkunastu lat znacząco wzrosło zainteresowanie polimerami zawierającymi boczne łańcuchy glikolu oligoetylenowego. Wśród polimerów tego typu największe znaczenie uzyskały poli(metakrylany glikoli oligoetylenowych) (POEGMA). Polimery te są biokompatybilne. Wiele z polimerów POEGMA wykazuje termoczułość w roztworach wodnych i wpłynie fizjologicznym, a ich przejście fazowe jest wąskie i charakteryzuje się nieznaczną histerezą. Przegląd obejmuje syntezę i samoorganizację homo- i kopolimerów POEGMA o różnej topologii makrocząsteczek. Zawiera także dane o otrzymywaniu termoczułych koniugatów POEGMA z substancjami aktywnymi biologicznie i możliwość wykorzystania takich biokoniugatów do otrzymywania nanonośników

Nanostructure of bovine pericardium treated with trypsin

Various methods of xenogeneic tissues stabilization have been proposed for the purpose of preparing many tissue-derived biomaterials. One of the most important treatments that may lead to obtaining the good-quality tissue biomaterials seems to be decellularization of such tissues. This process may contribute to the reduction of the most frequent failures resulting from the tissues stabilization. The aim of this work was to determine nanostructure of trypsin-treated bovine pericardium, using atomic force microscopy (AFM). The treatment of bovine pericardium with trypsin in EDTA solution resulted in non significant changes in tissue’s morphology. Demonstrated AFM studies of these tissues revealed no failures on the fibers’ surface in the nanoscale. Thus, our results confirm the expec-tation that decellularization may be considered as one of the most promising methods of the allogeneic and xenogeneic tissues stabilization

Structure of micelleplexes formed between QPDMAEMA-b-PLMA amphiphilic cationic copolymer micelles and DNA of different lengths

We study the structures of micelleplexes formed by quaternized poly(2-(dimethylamino) ethyl methacrylate)-b-poly(lauryl methacrylate) (QPDMAEMA-b-PLMA) amphiphilic cationic copolymer micelles interacting electrostatically with linear DNA of different lengths (113 and 2000 base pairs). QPDMAEMA-b-PLMA copolymers form micelles in aqueous milieu, with PLMA hydrophobic cores and QPDMAEMA cationic coronas. Nanosized micelleplexes were formed after mixing QPDMAEMA-b-PLMA micelles with DNAs, in a wide range of N/P ratios (nitrogen (N) of amine group of QPDMAEMA over phosphate (P) groups of DNA), as shown by Ultraviolet–Visible (UV–Vis) and fluorescence spectroscopy. Light scattering techniques demonstrated the formation of well-defined micelleplexes with monomodal and narrow size distributions, whose size and surface charge vary according to the N/P ratio. Micelleplexes presented stability under certain salt concentration. Spherical and worm-like micelleplexes were visualized by cryogenic transmission electron microscopy (Cryo-TEM). Overall, QPMDAEMA-b-PLMA micelles can efficiently interact with DNA. The stability, morphology and complexation of the micelleplexes were found to depend on copolymer molecular mass, the hydrophilic/hydrophobic ratio, the micellar structure, the length of DNA, the N/P ratio and the ionic strength. The findings demonstrate that QPDMAEMA-b-PLMA polyelectrolyte copolymer micelles have prospects for their application as non-viral vectors for nucleic acids delivery and gene therapy. © 2022 Elsevier Lt

Polimery w macierzach peptydowych/białkowych

Peptide and protein arrays have gained increasing attention due to their potential application in many areas of research, clinical diagnosis, and pharmacy. A typical array consists of asupport containing immobilized peptides or proteins positioned in an addressable format. The greatest advantage of the arrays is the possibility for miniaturization, which relies on dividing the surface into miniature spots, thus allowing for hundreds/thousands of analyses to be simultaneously performed using minimal amounts of aprecious biological material. The quality of assays with the use of peptide and protein arrays depends on the surface properties, e.g., hydrophilicity, homogeneity, density of functional groups, surface morphology, etc. In recent years, it was shown that the quality of the assays might be improved by introducing polymers acting as spacers between the peptide and the solid support. This approach causes changes in the surface properties, e.g., it reduces the undesirable non-specific adsorption of biomolecules, increases the density of functional groups, or can improve the biological activity of biomolecules attached to the surface. In this review, various types of polymers that are used for peptide and protein arrays and their impact on the assay quality are discussed.Peptydy lub białka naniesione w regularnych, uporządkowanych pozycjach na nośnik stały tworzą tzw. macierze. Układy takie wzbudzają coraz większe zainteresowanie, ponieważ można je wykorzystywać do prowadzenia analiz w biochemii, diagnostyce klinicznej czy farmacji. Największą zaletą macierzy jest możliwość miniaturyzacji. Podział powierzchni macierzy na mikroplamki (mikrospoty) pozwala na wykonywanie do kilkuset analiz jednocześnie z wykorzystaniem minimalnej ilości cennego materiału biologicznego. Jakość analiz przeprowadzanych przy użyciu macierzy peptydowych i białkowych zależy od takich właściwości powierzchni, jak: hydrofilowość, jednorodność, gęstość obsadzenia grupami funkcyjnymi, morfologia, itp. W ostatnich latach wykazano, że można poprawić jakość analiz w wyniku wprowadzenia polimerów między peptyd/białko a podłoże. Polimery zmieniają właściwości powierzchni macierzy, np. redukują niepożądaną adsorpcję biocząsteczek, zwiększają gęstość obsadzenia powierzchni grupami funkcyjnymi lub poprawiają dostępność biocząsteczek związanych z powierzchnią. W niniejszej pracy omówiono różne typy polimerów stosowane do otrzymywania macierzy peptydowych i białkowych oraz ich wpływ na jakość przeprowadzanych analiz

Room temperature single-step synthesis of metal decorated boron-rich nanowires via laser ablation

Hybrid nanostructures, such as those with nanoparticles anchored on the surface of nanowires, or decorated nanowires, have a large number of potential and tested applications such as: gas sensing, catalysis, plasmonic waveguides, supercapacitors and more. The downside of these nanostructures is their production. Generally, multi-step synthesis procedures are used, with the nanowires and the nanoparticles typically produced separately and then integrated. The few existent single-step methods are lengthy or necessitate highly dedicated setups. In this paper we report a single-step and rapid (ca. 1 min) laser ablation synthesis method which produces a wide variety of boron-rich decorated nanowires. Furthermore, the method is carried at room temperature. The synthesis process consists on a filamentary jet ejection process driven by pressure gradients generated by the ablation plume on the rims of the irradiation crater. Simultaneously nanoparticles are nucleated and deposited on the filaments thus producing hybrid decorated nanowires

Enzyme assays based on polymer-substrate arrays

Ocena aktywności enzymów jest kluczowym zagadnieniem w badaniu kinetyki reakcji enzymatycznych i inhibicji. Ostatnio, macierze polimerowo-peptydowe, gdzie peptyd jest specyficznym substratem dla enzymu wzbudzają coraz większe zainteresowanie wśród biochemików. W połączeniu z czułymi metodami detekcji takimi jak spektrometria mas i fluorescencja macierze mogą znaleźć zastosowanie jako niezwykle użyteczne narzędzia do detekcji enzymów i oceny ich aktywności w diagnostyce klinicznej. Macierze peptydowe składają się z powierzchni, na której immobilizowane są peptydy . Peptydy mogą być przyłączone bezpośrednio do sfunkcjonalizowanej powierzchni lub poprzez polimerowy linker. Obecność polimerowego linkera pomiędzy powierzchnią a peptydem przynosi wiele korzyści. Zastosowanie linkera z poli(tlenku etylenu) minimalizuje niespecyficzną adsorpcję biomolekuł na podłożu, zapewnia niskie tło w pomiarach fluorescencyjnych i ułatwia dostęp steryczny centrum aktywnego do peptydu. W niniejszej pracy koniugaty peptydów z poli(tlenkiem etylenu) zostały otrzymane na drodze syntezy na nośniku stałym metodą Fmoc. Otrzymane koniugaty immobilizowano na powierzchni krzemu zmodyfikowanej aminopropy lotrietoksy silanem. Powierzchnię scharakteryzowano techniką AFM i zbadano jej kąt zwilżania. Tak otrzymane macierze peptydowe poddano inkubacji z enzymami a produkty reakcji analizowano za pomocą techniki ESI MS.Enzyme assays are methods for measuring enzymatic activity, they are vital to study enzyme kinetics and enzyme inhibitors. Recently, polymer-peptide arrays where the peptide is specific substrate for the enzyme have attracted high attention. Such arrays can be applied as invaluable tools for enzyme recognition when connected to fluorescence or mass spectrometry detection. Peptide arrays consist of peptides immobilized on solid support directly or through polymeric linker. It w as shown that the presence of poly(ethylene oxide) as a linker between surface and the peptide offers many advantages. It minimizes non-specific binding of biomolecules on the surface, provides low background in fluorescence measurement, avoids steric hindrance , and thus makes linked peptide fully accessible the active site of an enzyme. In this work, conjugate of peptide and poly(ethylene oxide) were synthesized on the Tentagel resin using solid phase Fmoc chemistry, and then covalently immobilized by grafting-to method on the silica surface. Silica plates before grafting were modified by 3-aminopropy ltriethoxy silane and characterized by AFM and contact angel measurement. The obtained peptide arrays were incubated with enzymes and products of these reactions were analyzed by ESI MS

A thermal analysis and physicochemical study on thermoresponsive chimeric liposomal nanosystems

Thermoresponsive nanomaterials have led to a plethora of new applications in the fields of Nanobiotechnology, Biomedicine and Therapeutics. Since liposomal membranes are lyotropic liquid crystals, the development of thermoresponsive liposomes for drug delivery has been recognized as an attractive scientific field. Additionally, plenty of studies utilizing the temperature-dependent response of certain synthetic polymers are conducted, alone or in combination with liposomes. In the present study, we combined the liposomal and thermoresponsive polymer technologies, in order to create functional chimeric/mixed liposomal nanosystems with innovative properties. Initially, differential scanning calorimetry was applied on chimeric/mixed bilayers to evaluate the effect of polymeric guests on the thermotropic behavior of lipidic membranes. Thereafter, chimeric/mixed liposomes were built and their physicochemical properties, as well as their colloidal stability were measured and evaluated. The nature of the self-assembled structures and the lipidic membrane morphology were investigated through cryo-transmission electron microscopy, while their thermoresponsiveness and its consequences on the lipidic membrane properties were assessed, through a simple heating protocol. The presence of a new thermodynamic phase on the lipidic membrane acts as an agglomeration and aggregation inducer, affecting the whole colloidal chimeric/mixed nanosystem. This mechanism might be characterized as “phase functionality” and may be utilized for drug delivery purposes and also in other applications. Biophysics and thermodynamics are very important tools to study the self-assembly process, as well as the stability and bio-functionality of drug delivery systems. © 2019, Akadémiai Kiadó, Budapest, Hungary

Coexistence of Toxoplasma gondii and Cytomegalovirus infections in infants

Coexistence of Toxoplasma gondii and Cytomegalovirus infection in 3 dystrophic newborns is discussed. Also the not very characteristic course of the infection is stressed

New thermoresponsive polymer layers for skin cell culture and detachment

Covalent attachment of a thermoresponsive polymer to solid support leads to layers exhibiting temperature-dependent properties. Below the cloud point temperature (TCP) of the thermoresponsive polymer the layer is hydrophilic – it is hydrated and polymer chains adopt an expanded conformation. Above TCP, the polymer chains collapse due to dehydration and the surface becomes hydrophobic. This is a reversible process, lowering the temperature cause hydration and swelling of the layer. Such thermoresponsive layers can be obtained via reactions of entities present on the surface (e.g. functional groups, radicals etc.) with complementary functionalities in the polymer chains (grafting to) or with monomer subjected to polymerization (grafting from). Thermoresponsive layers may be used in many biomedical applications such as separation of molecules or cell sheet engineering. In this work, well-defined thermoresponsive (co)polymers of glycidol and ethyl glycidyl carbamate (mPGl), 2-ethyl and 2-nonyl-2-oxazoline (PENOx) as well as homopolymers of 2-isopropyl-2-oxazoline (PIPOx) were grafted to functionalized glass and silica substrates with the aim to obtain thermoresponsive layers for potential application in cell sheet engineering. Presence of polymers covalently bonded to substrates was confirmed by FT-IR and XPS studies. The polymer layers were 5-50 nm thick, depending on the molar mass and polymer concentration. Microscopic techniques indicated a smooth surface of mPGl layers, slightly rough texture of PENOx layers and fibrille-like fibers surface of PIPOx layers. Ellipsometry and contact angle studies revealed the response of layers to temperature changes. Biocompatibility of layers with dermal fibroblasts was confirmed by toxicity tests. Thermoresponsive surfaces were employed as substrates for skin cell culture and harvesting. Fibroblasts adhesion and proliferation on investigated surfaces was comparable with control sample. A confluent cell sheet was formed after 24 hours of culture. The influence of surface properties on cell adhesion and proliferation was examined. Detachment of cells from surfaces was controlled by variation of the temperature. An intact monolayer of cultured dermal fibroblasts was detached. No mechanical or enzymatic methods were required to harvest the cell sheets. Skin cell sheets, detached from thermoresponsive polymer layers may be applied in the cell sheet engineering that is highly desirable in tissue regeneration