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1.
Soft Matter ; 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34605513

RESUMO

Spherical particles from shape-memory polymers (SMP) can be stretched to ellipsoids with high aspect ratio (AR) and temporarily stabilized. They can switch back to low AR upon thermal stimulation. Here, the creation of an alternative shape-switching capability of particles from low to high AR is introduced, where a SMP matrix from polyvinyl alcohol (PVA) is used to create crosslinked high AR particles and to program the embedded micrometer-sized particles from a second SMP (oligo(ε-caprolactone) micronetworks, MN) with a low switching temperature Tsw. This programming proceeds through shape-recovery of the PVA matrix, from which the MN are harvested by PVA matrix dissolution. The use of a dissolvable SMP matrix may be a general strategy to efficiently create systems with complex moving capabilities.

2.
MRS Commun ; : 1-9, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34513262

RESUMO

In vitro thrombogenicity test systems require co-cultivation of endothelial cells and platelets under blood flow-like conditions. Here, a commercially available perfusion system is explored using plasma-treated cyclic olefin copolymer (COC) as a substrate for the endothelial cell layer. COC was characterized prior to endothelialization and co-cultivation with platelets under static or flow conditions. COC exhibits a low roughness and a moderate hydrophilicity. Flow promoted endothelial cell growth and prevented platelet adherence. These findings show the suitability of COC as substrate and the importance of blood flow-like conditions for the assessment of the thrombogenic risk of drugs or cardiovascular implant materials. Supplementary Information: The online version contains supplementary material available at 10.1557/s43579-021-00072-6.

3.
Artigo em Inglês | MEDLINE | ID: mdl-34542065

RESUMO

Multiblock copolymers type PDC are polyetheresterurethanes composed of poly(ɛ-caprolactone) and poly(p-dioxanone) segments. They were designed as degradadable shape-memory polymers for medical devices, which can be implanted minimally-invasively. While providing structural support in the initial phase after implantation, they are capable to modulate soft tissue regeneration while degradation. In this perspective, we elucidate cell-material interactions, compatibility both in-vitro and in-vivo and biofunctionality of PDC, which represents a promising candidate biomaterial family especially for cardiovascular applications.

4.
Clin Hemorheol Microcirc ; 79(1): 217-230, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34487028

RESUMO

Human induced pluripotent stem cells (hiPSCs) are a promising cell source to generate the patient-specific lung organoid given their superior differentiation potential. However, the current 3D cell culture approach is tedious and time-consuming with a low success rate and high batch-to-batch variability. Here, we explored the establishment of lung bud organoids by systematically adjusting the initial confluence levels and homogeneity of cell distribution. The efficiency of single cell seeding and clump seeding was compared. Instead of the traditional 3D culture, we established a 2.5D organoid culture to enable the direct monitoring of the internal structure via microscopy. It was found that the cell confluence and distribution prior to induction were two key parameters, which strongly affected hiPSC differentiation trajectories. Lung bud organoids with positive expression of NKX 2.1, in a single-cell seeding group with homogeneously distributed hiPSCs at 70% confluence (SC_70%_hom) or a clump seeding group with heterogeneously distributed cells at 90% confluence (CL_90%_het), can be observed as early as 9 days post induction. These results suggest that a successful lung bud organoid formation with single-cell seeding of hiPSCs requires a moderate confluence and homogeneous distribution of cells, while high confluence would be a prominent factor to promote the lung organoid formation when seeding hiPSCs as clumps. 2.5D organoids generated with defined culture conditions could become a simple, efficient, and valuable tool facilitating drug screening, disease modeling and personalized medicine.

5.
Clin Hemorheol Microcirc ; 79(1): 205-216, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34487031

RESUMO

BACKGROUND: Polymeric materials have been widely used as artificial grafts in cardiovascular applications. These polymeric implants can elicit a detrimental innate and adaptive immune response after interacting with peripheral blood. A surface modification with components from extracellular matrices (ECM) may minimize the activation of immune cells from peripheral blood. The aim of this study is to compare the cellular response of blood-born immune cells to the fiber meshes from polyesteretherurethane (PEEUm) and PEEUm with ECM coating (PEEUm + E). MATERIALS AND METHODS: Electrospun PEEUm were used as-is or coated with human cardiac ECM. Different immune cells were isolated form human peripheral blood. Cytokine release profile from naïve and activated monocytes was assessed. Macrophage polarization and T cell proliferation, as indication of immune response were evaluated. RESULTS: There was no increase in cytokine release (IL-6, TNF-α, and IL-10) from activated monocytes, macrophages and mononuclear cells on PEEUm; neither upon culturing on PEEUm + E. Naïve monocytes showed increased levels of IL-6 and TNF-α, which were not present on PEEUm + E. There was no difference on monocyte derived macrophage polarization towards pro-inflammatory M1 or anti-inflammatory M2 on PEEUm and PEEUm + E. Moreover, T cell proliferation was not increased upon interacting with PEEUm directly. CONCLUSION: As PEEUm only elicits a minimal response from naïve monocytes but not from monocytes, peripheral blood mononuclear cells (PBMCs) or T cells, the slight improvement in response to PEEUm + E might not justify the additional effort of coating with a human ECM.

6.
Artigo em Inglês | MEDLINE | ID: mdl-34366331

RESUMO

Biofouling on medical device surfaces, which is initiated by protein adsorption and adhesion of microbes especially the antibiotic-resistant bacteria, attracts global attention for centuries due to its enduring challenges in healthcare. Here, the antifouling effect of hydrophilic poly(glycerol glycidyl ether) (polyGGE) film is explored in comparison to hemocompatible and protein-resistant control polymers. The chemical and thermomechanical stability of polyGGE in hydrated conditions at body temperature was achieved via adjusting UV curing and KOH quenching time. The polyGGE surface is inert to the plasma protein adsorption and interfered the metabolism conditions, biofilm formation and growth of both Gram negative (Gram-) and antibiotic-resistant Gram positive (Gram+) bacteria. These results indicate the potential application of polyGGE for combating the risk of hospital-acquired infections and preventing drug-resistant superbug spreading.

7.
Artigo em Inglês | MEDLINE | ID: mdl-34420943

RESUMO

Sulfated biomolecules are known to influence numerous biological processes in all living organisms. Particularly, they contribute to prevent and inhibit the hypercoagulation condition. The failure of polymeric implants and blood contacting devices is often related to hypercoagulation and microbial contamination. Here, bioactive sulfated biomacromolecules are mimicked by sulfation of poly(glycerol glycidyl ether) (polyGGE) films. Autoclaving, gamma-ray irradiation and ethylene oxide (EtO) gas sterilization techniques were applied to functionalized materials. The sulfate group density and hydrophilicity of sulfated polymers were decreased while chain mobility and thermal degradation were enhanced post autoclaving when compared to those after EtO sterilization. These results suggest that a quality control after sterilization is mandatory to ensure the amount and functionality of functionalized groups are retained.

8.
Int J Mol Sci ; 22(13)2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34209789

RESUMO

Near-physiological in vitro thrombogenicity test systems for the evaluation of blood-contacting endothelialized biomaterials requires co-cultivation with platelets (PLT). However, the addition of PLT has led to unphysiological endothelial cell (EC) detachment in such in vitro systems. A possible cause for this phenomenon may be PLT activation triggered by the applied endothelial cell medium, which typically consists of basal medium (BM) and nine different supplements. To verify this hypothesis, the influence of BM and its supplements was systematically analyzed regarding PLT responses. For this, human platelet rich plasma (PRP) was mixed with BM, BM containing one of nine supplements, or with BM containing all supplements together. PLT adherence analysis was carried out in six-channel slides with plasma-treated cyclic olefin copolymer (COC) and poly(tetrafluoro ethylene) (PTFE, as a positive control) substrates as part of the six-channel slides in the absence of EC and under static conditions. PLT activation and aggregation were analyzed using light transmission aggregometry and flow cytometry (CD62P). Medium supplements had no effect on PLT activation and aggregation. In contrast, supplements differentially affected PLT adherence, however, in a polymer- and donor-dependent manner. Thus, the use of standard endothelial growth medium (BM + all supplements) maintains functionality of PLT under EC compatible conditions without masking the differences of PLT adherence on different polymeric substrates. These findings are important prerequisites for the establishment of a near-physiological in vitro thrombogenicity test system assessing polymer-based cardiovascular implant materials in contact with EC and PLT.


Assuntos
Materiais Biocompatíveis/farmacologia , Plaquetas/efeitos dos fármacos , Plaquetas/fisiologia , Meios de Cultura/farmacologia , Adulto , Materiais Biocompatíveis/química , Plaquetas/citologia , Meios de Cultura/química , Endotélio/citologia , Feminino , Humanos , Masculino , Teste de Materiais , Pessoa de Meia-Idade , Ativação Plaquetária/efeitos dos fármacos , Adesividade Plaquetária/efeitos dos fármacos , Agregação Plaquetária/efeitos dos fármacos , Polímeros/farmacologia , Tecidos Suporte/química
9.
MRS Commun ; : 1-7, 2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34258101

RESUMO

Abstract: Toll-like receptor (TLR) can trigger an immune response against virus including SARS-CoV-2. TLR expression/distribution is varying in mesenchymal stromal cells (MSCs) depending on their culture environments. Here, to explore the effect of periodic thermomechanical cues on TLRs, thermally controlled shape-memory polymer sheets with programmable actuation capacity were created. The proportion of MSCs expressing SARS-CoV-2-associated TLRs was increased upon stimulation. The TLR4/7 colocalization was promoted and retained in the endoplasmic reticula. The TLR redistribution was driven by myosin-mediated F-actin assembly. These results highlight the potential of boosting the immunity for combating COVID-19 via thermomechanical preconditioning of MSCs. Graphic abstract: Periodic thermal and synchronous mechanical stimuli provided by polymer sheet actuators selectively promoted the expression of SARS-CoV-2-associated TLRs 4 and 7 in adipose-derived MSCs and recruited TLR4 to Endoplasmic reticulum region where TLR7 was located via controlling myosin-mediated F-actin cytoskeleton assembly.

10.
Int J Mol Sci ; 22(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34072689

RESUMO

Shape-memory hydrogels (SMH) are multifunctional, actively-moving polymers of interest in biomedicine. In loosely crosslinked polymer networks, gelatin chains may form triple helices, which can act as temporary net points in SMH, depending on the presence of salts. Here, we show programming and initiation of the shape-memory effect of such networks based on a thermomechanical process compatible with the physiological environment. The SMH were synthesized by reaction of glycidylmethacrylated gelatin with oligo(ethylene glycol) (OEG) α,ω-dithiols of varying crosslinker length and amount. Triple helicalization of gelatin chains is shown directly by wide-angle X-ray scattering and indirectly via the mechanical behavior at different temperatures. The ability to form triple helices increased with the molar mass of the crosslinker. Hydrogels had storage moduli of 0.27-23 kPa and Young's moduli of 215-360 kPa at 4 °C. The hydrogels were hydrolytically degradable, with full degradation to water-soluble products within one week at 37 °C and pH = 7.4. A thermally-induced shape-memory effect is demonstrated in bending as well as in compression tests, in which shape recovery with excellent shape-recovery rates Rr close to 100% were observed. In the future, the material presented here could be applied, e.g., as self-anchoring devices mechanically resembling the extracellular matrix.


Assuntos
Materiais Biocompatíveis , Gelatina , Hidrogéis , Materiais Inteligentes , Temperatura , Gelatina/química , Hidrogéis/metabolismo , Hidrólise , Fenômenos Mecânicos , Estrutura Molecular , Polímeros , Materiais Inteligentes/química , Análise Espectral , Engenharia Tecidual
11.
J R Soc Interface ; 18(178): 20210040, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33975461

RESUMO

Climbing plants must reach supports and navigate gaps to colonize trees. This requires a structural organization ensuring the rigidity of so-called 'searcher' stems. Cacti have succulent stems adapted for water storage in dry habitats. We investigate how a climbing cactus Selenicereus setaceus develops its stem structure and succulent tissues for climbing. We applied a 'wide scale' approach combining field-based bending, tensile and swellability tests with fine-scale rheological, compression and anatomical analyses in laboratory conditions. Gap-spanning 'searcher' stems rely significantly on the soft cortex and outer skin of the stem for rigidity in bending (60-94%). A woody core contributes significantly to axial and radial compressive strength (80%). Rheological tests indicated that storage moduli were consistently higher than loss moduli indicating that the mucilaginous cortical tissue behaved like a viscoelastic solid with properties similar to physical or chemical hydrogels. Rheological and compression properties of the soft tissue changed from young to old stages. The hydrogel-skin composite is a multi-functional structure contributing to rigidity in searcher stems but also imparting compliance and benign failure in environmental situations when stems must fail. Soft tissue composites changing in function via changes in development and turgescence have a great potential for exploring candidate materials for technical applications.


Assuntos
Cactaceae , Força Compressiva , Hidrogéis , Pressão , Árvores
12.
Biomacromolecules ; 22(5): 1875-1884, 2021 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-33724816

RESUMO

Bio-interactive hydrogel formation in situ requires sensory capabilities toward physiologically relevant stimuli. Here, we report on pH-controlled in situ hydrogel formation relying on latent cross-linkers, which transform from pH sensors to reactive molecules. In particular, thiopeptolide/thio-depsipeptides were capable of pH-sensitive thiol-thioester exchange reactions to yield α,ω-dithiols, which react with maleimide-functionalized multi-arm polyethylene glycol to polymer networks. Their water solubility and diffusibility qualify thiol/thioester-containing peptide mimetics as sensory precursors to drive in situ localized hydrogel formation with potential applications in tissue regeneration such as treatment of inflamed tissues of the urinary tract.


Assuntos
Hidrogéis , Compostos de Sulfidrila , Concentração de Íons de Hidrogênio , Polietilenoglicóis , Polímeros
13.
ACS Appl Mater Interfaces ; 13(9): 10748-10759, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33594879

RESUMO

High levels of reactive oxygen species (ROS) during stem cell expansion often lead to replicative senescence. Here, a polydopamine (PDA)-coated substrate was used to scavenge extracellular ROS for mesenchymal stem cell (MSC) expansion. The PDA-coated substrate could reduce the oxidative stress and mitochondrial damage in replicative senescent MSCs. The expression of senescence-associated ß-galactosidase of MSCs from three human donors (both bone marrow- and adipose tissue-derived) was suppressed on PDA. The MSCs on the PDA-coated substrate showed a lower level of interleukin 6 (IL-6), one of the senescence-associated inflammatory components. Cellular senescence-specific genes, such as p53 and p21, were downregulated on the PDA-coated substrate, while the stemness-related gene, OCT4, was upregulated. The PDA-coated substrate strongly promoted the proliferation rate of MSCs, while the stem cell character and differentiation potential were retained. Large-scale expansion of stem cells would greatly benefit from the PDA-coated substrate.


Assuntos
Técnicas de Cultura de Células/métodos , Materiais Revestidos Biocompatíveis/farmacologia , Indóis/farmacologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Polímeros/farmacologia , Técnicas de Cultura de Células/instrumentação , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Senescência Celular/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Humanos , Interleucina-6/metabolismo , Mitocôndrias/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , beta-Galactosidase/metabolismo
14.
Int J Mol Sci ; 22(3)2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33540846

RESUMO

The adherence and shear-resistance of human umbilical venous endothelial cells (HUVEC) on polymers is determined in vitro in order to qualify cardiovascular implant materials. In these tests, variable fractions of HUVEC do not adhere to the material but remain suspended in the culture medium. Nonadherent HUVEC usually stop growing, rapidly lose their viability and can release mediators able to influence the growth and function of the adherent HUVEC. The aim of this study was the investigation of the time dependent behaviour of HUVEC under controlled nonadherent conditions, in order to gain insights into potential influences of these cells on their surrounding environment in particular adherent HUVEC in the context of in vitro biofunctionality assessment of cardiovascular implant materials. Data from adherent or nonadherent HUVEC growing on polystyrene-based cell adhesive tissue culture plates (TCP) or nonadhesive low attachment plates (LAP) allow to calculate the number of mediators released into the culture medium either from adherent or nonadherent cells. Thus, the source of the inflammatory mediators can be identified. For nonadherent HUVEC, a time-dependent aggregation without further proliferation was observed. The rate of apoptotic/dead HUVEC progressively increased over 90% within two days. Concomitant with distinct blebbing and loss of membrane integrity over time, augmented releases of prostacyclin (PGI2, up to 2.91 ± 0.62 fg/cell) and platelet-derived growth factor BB (PDGF-BB, up to 1.46 ± 0.42 fg/cell) were detected. The study revealed that nonadherent, dying HUVEC released mediators, which can influence the surrounding microenvironment and thereby the results of in vitro biofunctionality assessment of cardiovascular implant materials. Neglecting nonadherent HUVEC bears the risk for under- or overestimation of the materials endothelialization potential, which could lead to the loss of relevant candidates or to uncertainty with regard to their suitability for cardiac applications. One approach to minimize the influence from nonadherent endothelial cells could be their removal shortly after observing initial cell adhesion. However, this would require an individual adaptation of the study design, depending on the properties of the biomaterial used.


Assuntos
Adesão Celular/fisiologia , Técnicas de Cultura de Células , Células Endoteliais da Veia Umbilical Humana/citologia , Apoptose , Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Morte Celular , Divisão Celular , Meios de Cultivo Condicionados/química , Citocinas/análise , Epoprostenol/análise , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Mediadores da Inflamação/análise , Peptídeos e Proteínas de Sinalização Intercelular/análise , L-Lactato Desidrogenase/análise , Poliestirenos , Proteínas Recombinantes/farmacologia , Propriedades de Superfície , Tromboxano A2/análise , Fator de Necrose Tumoral alfa/farmacologia
15.
ACS Appl Mater Interfaces ; 13(7): 8095-8101, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33555174

RESUMO

Enzymes can support the synthesis or degradation of biomacromolecules in natural processes. Here, we demonstrate that enzymes can induce a macroscopic-directed movement of microstructured hydrogels following a mechanism that we call a "Jack-in-the-box" effect. The material's design is based on the formation of internal stresses induced by a deformation load on an architectured microscale, which are kinetically frozen by the generation of polyester locking domains, similar to a Jack-in-the-box toy (i.e., a compressed spring stabilized by a closed box lid). To induce the controlled macroscopic movement, the locking domains are equipped with enzyme-specific cleavable bonds (i.e., a box with a lock and key system). As a result of enzymatic reaction, a transformed shape is achieved by the release of internal stresses. There is an increase in entropy in combination with a swelling-supported stretching of polymer chains within the microarchitectured hydrogel (i.e., the encased clown pops-up with a pre-stressed movement when the box is unlocked). This utilization of an enzyme as a physiological stimulus may offer new approaches to create interactive and enzyme-specific materials for different applications such as an optical indicator of the enzyme's presence or actuators and sensors in biotechnology and in fermentation processes.


Assuntos
Materiais Biocompatíveis/metabolismo , Hidrogéis/metabolismo , Lipase/metabolismo , Poliésteres/metabolismo , Materiais Biocompatíveis/química , Hidrogéis/química , Lipase/química , Tamanho da Partícula , Poliésteres/química , Pseudomonas fluorescens/enzimologia , Propriedades de Superfície
16.
Int J Mol Sci ; 22(2)2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33478148

RESUMO

Although cardiovascular devices are mostly implanted in arteries or to replace arteries, in vitro studies on implant endothelialization are commonly performed with human umbilical cord-derived venous endothelial cells (HUVEC). In light of considerable differences, both morphologically and functionally, between arterial and venous endothelial cells, we here compare HUVEC and human umbilical cord-derived arterial endothelial cells (HUAEC) regarding their equivalence as an endothelial cell in vitro model for cardiovascular research. No differences were found in either for the tested parameters. The metabolic activity and lactate dehydrogenase, an indicator for the membrane integrity, slightly decreased over seven days of cultivation upon normalization to the cell number. The amount of secreted nitrite and nitrate, as well as prostacyclin per cell, also decreased slightly over time. Thromboxane B2 was secreted in constant amounts per cell at all time points. The Von Willebrand factor remained mainly intracellularly up to seven days of cultivation. In contrast, collagen and laminin were secreted into the extracellular space with increasing cell density. Based on these results one might argue that both cell types are equally suited for cardiovascular research. However, future studies should investigate further cell functionalities, and whether arterial endothelial cells from implantation-relevant areas, such as coronary arteries in the heart, are superior to umbilical cord-derived endothelial cells.


Assuntos
Pesquisa Biomédica , Doenças Cardiovasculares/terapia , Células Endoteliais da Veia Umbilical Humana/citologia , Artérias Umbilicais/citologia , Implantes Absorvíveis , Citoesqueleto de Actina/metabolismo , Pesquisa Biomédica/métodos , Pesquisa Biomédica/tendências , Doenças Cardiovasculares/etiologia , Terapia Baseada em Transplante de Células e Tecidos/métodos , Terapia Baseada em Transplante de Células e Tecidos/tendências , Células Cultivadas , Endotélio Vascular/citologia , Endotélio Vascular/metabolismo , Matriz Extracelular/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Medicina Regenerativa/métodos , Medicina Regenerativa/tendências , Engenharia Tecidual/métodos , Engenharia Tecidual/tendências , Artérias Umbilicais/metabolismo , Fator de von Willebrand/metabolismo
17.
ACS Biomater Sci Eng ; 7(2): 527-540, 2021 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-33496571

RESUMO

The establishment of confluent endothelial cell (EC) monolayers on implanted materials has been identified as a concept to avoid thrombus formation but is a continuous challenge in cardiovascular device engineering. Here, material properties of gelatin-based hydrogels obtained by reacting gelatin with varying amounts of lysine diisocyanate ethyl ester were correlated with the functional state of hydrogel contacting venous EC (HUVEC) and HUVEC's ability to form a monolayer on these hydrogels. The density of adherent HUVEC on the softest hydrogel at 37 °C (G' = 1.02 kPa, E = 1.1 ± 0.3 kPa) was significantly lower (125 mm-1) than on the stiffer hydrogels (920 mm-1; G' = 2.515 and 5.02 kPa, E = 4.8 ± 0.8 and 10.3 ± 1.2 kPa). This was accompanied by increased matrix metalloprotease activity (9 pmol·min-2 compared to 0.6 pmol·min-2) and stress fiber formation, while cell-to-cell contacts were comparable. Likewise, release of eicosanoids (e.g., prostacyclin release of 1.7 vs 0.2 pg·mL-1·cell-1) and the pro-inflammatory cytokine MCP-1 (8 vs <1.5 pg·mL-1·cell-1) was higher on the softer than on the stiffer hydrogels. The expressions of pro-inflammatory markers COX-2, COX-1, and RAGE were slightly increased on all hydrogels on day 2 (up to 200% of the control), indicating a weak inflammation; however, the levels dropped to below the control from day 6. The study revealed that hydrogels with higher moduli approached the status of a functionally confluent HUVEC monolayer. The results indicate the promising potential especially of the discussed gelatin-based hydrogels with higher G' as biomaterials for implants foreseen for the venous system.


Assuntos
Gelatina , Hidrogéis , Materiais Biocompatíveis , Células Endoteliais , Próteses e Implantes
18.
Clin Hemorheol Microcirc ; 77(2): 201-219, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33185590

RESUMO

The size of particulate carriers is key to their transport and distribution in biological systems, and needs to be tailored in the higher submicron range to enable follicular uptake for dermal treatment. Oligodepsipeptides are promising nanoparticulate carrier systems as they can be designed to exhibit enhanced interaction with drug molecules. Here, a fabrication scheme for drug-loaded submicron particles from oligo[3-(S)-sec-butylmorpholine-2,5-dione]diol (OBMD) is presented based on an emulsion solvent evaporation method with cosolvent, surfactant, and polymer concentration as variable process parameters. The particle size (300-950 nm) increased with lower surfactant concentration and higher oligomer concentration. The addition of acetone increased the particle size at low surfactant concentration. Particle size remained stable upon the encapsulation of models compounds dexamethasone (DXM) and Nile red (NR), having different physicochemical properties. DXM was released faster compared to NR due to its higher water solubility. Overall, the results indicated that both drug-loading and size control of OBMD submicron particles can be achieved. When applied on porcine ear skin samples, the NR-loaded particles have been shown to allow NR penetration into the hair follicle and the depth reached with the 300 nm particles was comparable to the one reached with the cream formulation. A potential benefit of the particles compared to a cream is their sustained release profile.


Assuntos
Nanopartículas/química , Animais , Depsipeptídeos/química , Humanos , Tamanho da Partícula , Suínos
19.
J Mol Med (Berl) ; 98(12): 1767-1779, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33146744

RESUMO

Advanced non-viral gene delivery experiments often require co-delivery of multiple nucleic acids. Therefore, the availability of reliable and robust co-transfection methods and defined selection criteria for their use in, e.g., expression of multimeric proteins or mixed RNA/DNA delivery is of utmost importance. Here, we investigated different co- and successive transfection approaches, with particular focus on in vitro transcribed messenger RNA (IVT-mRNA). Expression levels and patterns of two fluorescent protein reporters were determined, using different IVT-mRNA doses, carriers, and cell types. Quantitative parameters determining the efficiency of co-delivery were analyzed for IVT-mRNAs premixed before nanocarrier formation (integrated co-transfection) and when simultaneously transfecting cells with separately formed nanocarriers (parallel co-transfection), which resulted in a much higher level of expression heterogeneity for the two reporters. Successive delivery of mRNA revealed a lower transfection efficiency in the second transfection round. All these differences proved to be more pronounced for low mRNA doses. Concurrent delivery of siRNA with mRNA also indicated the highest co-transfection efficiency for integrated method. However, the maximum efficacy was shown for successive delivery, due to the kinetically different peak output for the two discretely operating entities. Our findings provide guidance for selection of the co-delivery method best suited to accommodate experimental requirements, highlighting in particular the nucleic acid dose-response dependence on co-delivery on the single-cell level.

20.
Clin Hemorheol Microcirc ; 76(2): 317-327, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32925012

RESUMO

BACKGROUND: Keratinocytes are exposed to a thermal gradient throughout epidermal layers in human skin depending on environmental temperatures. OBJECTIVE: Here, the effect of cyclic temperature changes (ΔT) on HaCaT cell behaviors was explored. METHODS: HaCaT cells were cultured at constant temperature (37 °C or 25 °C) or under ΔT conditions. The morphology, mechanics, cell cycle progression, proliferation, and lipid synthesis of HaCaT cells were determined. RESULTS: ΔT conditions led to the inhomogeneous arrangement of the cytoskeleton in HaCaT cells, which resulted in enlarged size, rounder shape, and increased stiffness. Accumulation in the G2/M phase in the cell cycle, a decreased proliferation rate, and a delayed lipogenesis were detected in HaCaT cells cultured under ΔT conditions. CONCLUSIONS: ΔT conditions resulted in the re-arrangement of the cytoskeleton in HaCaT cells, which showed similarity to the temperature-induced disassemble and re-assemble of cytoskeletons in keratinocyte in vivo. The altered cytoskeleton arrangement resulted in the cell enlargement and stiffening, which reflected the changes in cellular functions. The application of oscillatory temperature in the in vitro culture of keratinocytes provides a way to gain more insights into the role of skin in response to environmental stimuli and maintaining its homeostasis in vivo.


Assuntos
Queratinócitos/metabolismo , Microscopia de Força Atômica/métodos , Linhagem Celular , Humanos , Temperatura
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