by Keyword: Polylactic aci
Borras, N, Sanchez-Sanz, A, Sans, J, Estrany, F, Perez-Madrigal, MM, Aleman, C, (2023). Flexible electroactive membranes for the electrochemical detection of dopamine European Polymer Journal 187, 111915
In addition of a key catecholamine neurotransmitter, dopamine is is the metabolite predominantly produced by specific types of tumors (e.g. paragangliomas and neuroblastomas), which cannot be diagnosed using conven-tional sensitive tests. Within this context, development of flexible electrochemical sensors to monitor dopamine levels in physiological fluids for the early diagnosis and control of diseases related to abnormal levels of such compound, is necessary. In this work, a flexible self-supported membrane, which acts directly as electrode, has been developed to detect dopamine. The membrane consists of three nanoperforated polylactic acid (PLA) layers, which provide flexibility and mechanical integrity, separated by two layers of an electroactive copolymer, which are obtained by electrochemical copolymerization of 3,4-ethylenedioxythiophene and aniline. The sensitivity and detection limit provided by the electroactive copolymer, which is accessible to dopamine molecules through the nanoperforations of the PLA outer layers, is 1.846 mu A/(cm2.mu M) and 1.7 mu M, respectively, in a urea-rich environments that mimics urine. These values allow us to propose the self-standing flexible electrodes devel-oped in this study for the detection of dopamine in patients affected by paragangliomas and neuroblastomas tumors, which typically present dopamine concentrations between 2 and 7 mu M.
JTD Keywords: 4-ethylenedioxythiophene), Conducting polymer, Electrochemical sensor, Electrodes, Hydrogels, Poly(3, Polyaniline, Polylactic acid, Selective detection, Sensors, Supercapacitors
Fontana-Escartin A, Puiggalí-Jou A, Lanzalaco S, Bertran O, Alemán C, (2021). Manufactured Flexible Electrodes for Dopamine Detection: Integration of Conducting Polymer in 3D-Printed Polylactic Acid Advanced Engineering Materials 23,
Flexible electrochemical sensors based on electroactive materials have emerged as powerful analytical tools for biomedical applications requiring bioanalytes detection. Within this context, 3D printing is a remarkable technology for developing electrochemical devices, due to no design constraints, waste minimization, and batch manufacturing with high reproducibility. However, the fabrication of 3D printed electrodes is still limited by the in-house fabrication of conductive filaments, which requires the mixture of the electroactive material with melted of thermoplastic polymer (e.g., polylactic acid, PLA). Herein, a simple approach is presented for preparing electrochemical dopamine (DA) biosensors. Specifically, the surface of 3D-printed PLA specimens, which exhibit an elastic modulus and a tensile strength of 3.7 +/- 0.3 GPa and 47 +/- 1 MPa, respectively, is activated applying a 0.5 m NaOH solution for 30 min and, subsequently, poly(3,4-ethylenedioxythiophene) is polymerized in situ using aqueous solvent. The detection of DA with the produced sensors has been demonstrated by cyclic voltammetry, differential pulse voltammetry, and chronoamperometry. In summary, the obtained results reflect that low-cost electrochemical sensors, which are widely used in medicine and biotechnology, can be rapidly fabricated using the proposed approach that, although based on additive manufacturing, does not require the preparation of conductive filaments.
JTD Keywords: 3d printers, Additive manufacturing, Amines, Batch manufacturing, Biomedical applications, Chronoamperometry, Conducting polymer, Conducting polymers, Conductive filaments, Conservation, Cyclic voltammetry, Differential pulse voltammetry, Electroactive material, Electrochemical biosensor, Electrochemical devices, Electrochemical sensors, Electrodes, Electron emission, Flexible electrode, High reproducibility, Medical applications, Neurophysiology, Poly-3 ,4-ethylenedioxythiophene, Polyesters, Polylactic aci, Sodium hydroxide, Tensile strength, Thermoplastic polymer
Molina, B. G., Lopes-Rodrigues, M., Estrany, F., Michaux, C., Perpète, E. A., Armelin, E., Alemán, C., (2020). Free-standing flexible and biomimetic hybrid membranes for ions and ATP transport Journal of Membrane Science 601, 117931
The transport of metabolites across robust, flexible and free-standing biomimetic membranes made of three perforated poly (lactic acid) (pPLA) layers, separated by two anodically polymerized conducting layers of poly (3,4-ethylenedioxythiophene-co-3-dodecylthiophene), and functionalized on the external pPLA layers with a voltage dependent anion channel (VDAC) protein, has been demonstrated. The three pPLA layers offer robustness and flexibility to the bioactive platform and the possibility of obtaining conducing polymer layers by in situ anodic polymerization. The incorporation of dodecylthiophene units, which bear a 12 carbon atoms long linear alkyl chain, to the conducting layers allows mimicking the amphiphilic environment offered by lipids in cells, increasing 32% the efficiency of the functionalization. Electrochemical impedance measurements in NaCl and adenosine triphosphate (ATP) solutions prove that the integration of the VDAC porin inside the PLA perforations considerably increases the membrane conductivity and is crucial for the electrolyte diffusion. Such results open the door for the development of advanced sensing devices for a broad panel of biomedical applications.
JTD Keywords: Conducting polymers, Membrane proteins, Membranes, Polylactic acid, Self-supported films
de la Mata, Ana, Mateos-Timoneda, Miguel A., Nieto-Miguel, Teresa, Galindo, Sara, López-Paniagua, Marina, Planell, Josep A., Engel, Elisabeth, Calonge, Margarita, (2019). Poly-l/dl-lactic acid films functionalized with collagen IV as carrier substrata for corneal epithelial stem cells Colloids and Surfaces B: Biointerfaces 177, 121-129
Limbal epithelial stem cells (LESCs) are responsible for the renewal of corneal epithelium. Cultivated limbal epithelial transplantation is the current treatment of choice for restoring the loss or dysfunction of LESCs. To perform this procedure, a substratum is necessary for in vitro culturing of limbal epithelial cells and their subsequent transplantation onto the ocular surface. In this work, we evaluated poly-L/DL-lactic acid 70:30 (PLA) films functionalized with type IV collagen (col IV) as potential in vitro carrier substrata for LESCs. We first demonstrated that PLA-col IV films were biocompatible and suitable for the proliferation of human corneal epithelial cells. Subsequently, limbal epithelial cell suspensions, isolated from human limbal rings, were cultivated using culture medium that did not contain animal components. The cells adhered significantly faster to PLA-col IV films than to tissue culture plastic (TCP). The mRNA expression levels for the LESC specific markers, K15, P63α and ABCG2 were similar or greater (significantly in the case of K15) in limbal epithelial cells cultured on PLA-col IV films than limbal epithelial cells cultured on TCP. The percentage of cells expressing the corneal (K3, K12) and the LESC (P63α, ABCG2) specific markers was similar for both substrata. These results suggest that the PLA-col IV films promoted LESC attachment and helped to maintain their undifferentiated stem cell phenotype. Consequently, these substrata offer an alternative for the transplantation of limbal cells onto the ocular surface.
JTD Keywords: Corneal epithelium, Collagen IV, Limbal stem cells, Polylactic acid, Tissue engineering
Barbeck, Mike, Serra, Tiziano, Booms, Patrick, Stojanovic, Sanja, Najman, Stevo, Engel, Elisabeth, Sader, Robert, Kirkpatrick, Charles James, Navarro, Melba, Ghanaati, Shahram, (2017). Analysis of the in vitro degradation and the in vivo tissue response to bi-layered 3D-printed scaffolds combining PLA and biphasic PLA/bioglass components – Guidance of the inflammatory response as basis for osteochondral regeneration Bioactive Materials , 2, (4), 208-223
Abstract The aim of the present study was the inÂ vitro and inÂ vivo analysis of a bi-layered 3D-printed scaffold combining a PLA layer and a biphasic PLA/bioglass G5 layer for regeneration of osteochondral defects inÂ vivo Focus of the inÂ vitro analysis was on the (molecular) weight loss and the morphological and mechanical variations after immersion in SBF. The inÂ vivo study focused on analysis of the tissue reactions and differences in the implant bed vascularization using an established subcutaneous implantation model in CD-1 mice and established histological and histomorphometrical methods. Both scaffold parts kept their structural integrity, while changes in morphology were observed, especially for the PLA/G5 scaffold. Mechanical properties decreased with progressive degradation, while the PLA/G5 scaffolds presented higher compressive modulus than PLA scaffolds. The tissue reaction to PLA included low numbers of BMGCs and minimal vascularization of its implant beds, while the addition of G5 lead to higher numbers of BMGCs and a higher implant bed vascularization. Analysis revealed that the use of a bi-layered scaffold shows the ability to observe distinct inÂ vivo response despite the physical proximity of PLA and PLA/G5 layers. Altogether, the results showed that the addition of G5 enables to reduce scaffold weight loss and to increase mechanical strength. Furthermore, the addition of G5 lead to a higher vascularization of the implant bed required as basis for bone tissue regeneration mediated by higher numbers of BMGCs, while within the PLA parts a significantly lower vascularization was found optimally for chondral regeneration. Thus, this data show that the analyzed bi-layered scaffold may serve as an ideal basis for the regeneration of osteochondral tissue defects. Additionally, the results show that it might be able to reduce the number of experimental animals required as it may be possible to analyze the tissue response to more than one implant in one experimental animal.
JTD Keywords: Bioactive glass, Polylactic acid (PLA), Bi-layer scaffold, Multinucleated giant cells, Bone substitute, Vascularization, Calcium phosphate glass
Gugutkov, D., Gustavsson, J., Cantini, M., Salmeron-Sánchez, M., Altankov, G., (2017). Electrospun fibrinogen-PLA nanofibres for vascular tissue engineering Journal of Tissue Engineering and Regenerative Medicine 11, (10), 2774-2784
Here we report on the development of a new type of hybrid fibrinogen-polylactic acid (FBG-PLA) nanofibres (NFs) with improved stiffness, combining the good mechanical properties of PLA with the excellent cell recognition properties of native FBG. We were particularly interested in the dorsal and ventral cell response to the nanofibres' organization (random or aligned), using human umbilical endothelial cells (HUVECs) as a model system. Upon ventral contact with random NFs, the cells developed a stellate-like morphology with multiple projections. The well-developed focal adhesion complexes suggested a successful cellular interaction. However, time-lapse analysis shows significantly lowered cell movements, resulting in the cells traversing a relatively short distance in multiple directions. Conversely, an elongated cell shape and significantly increased cell mobility were observed in aligned NFs. To follow the dorsal cell response, artificial wounds were created on confluent cell layers previously grown on glass slides and covered with either random or aligned NFs. Time-lapse analysis showed significantly faster wound coverage (within 12 h) of HUVECs on aligned samples vs. almost absent directional migration on random ones. However, nitric oxide (NO) release shows that endothelial cells possess lowered functionality on aligned NFs compared to random ones, where significantly higher NO production was found. Collectively, our studies show that randomly organized NFs could support the endothelization of implants while aligned NFs would rather direct cell locomotion for guided neovascularization.
JTD Keywords: Electrospun nanofibers, Endothelial cells, Fibrinogen, Guided cellular behavior, Polylactic acid, Vascular tissue engineering
Keremidarska, M., Gugutkov, D., Altankov, G., Krasteva, N., (2015). Impact of electrospun nanofibres orientation on mesenchymal stem cell adhesion and morphology Comptes Rendus de L'Academie Bulgare des Sciences , 68, (10), 1271-1276
Electrospun nanofibrous materials mimicking the architecture of native extracellular matrix (ECM) hold great promise as scaffolds in tissue engineering. In order to optimize the properties of nanofibrous scaffolds it is important to understand the impact of fibresâ€™ organization on cell behaviour. Herein, we investigated the effect of nanofibres (NFs) alignment on human adipose-derived mesenchymal stem cells (hAD-MSCs) adhesion and morphology. Electrospun composite fibrinogen/poly-lactic acid (FNG/PLA) NF scaffolds with same composition and comparable fibre size were fabricated into randomly oriented and aligned configuration and stem cells adhesion was characterized by the meaning of overall cell morphology, actin cytoskeleton organization and expression of molecules, involved in the development of focal adhesion complexes. We found that hAD-MSCs altered their morphology, actin cytoskeleton and cell attachment in accordance with nanofibre orientation while cell spreading, focal adhesions and expression of Î²1 and Î±Nintegrin receptors were not influenced significantly by fibre orientation. These results confirmed that fibre alignment of scaffold guide cellular arrangement and could be beneficial for stem differentiation and therefore for the successful scaffolds development if its contact guidance coincided with the cell shape and cytoskeletal tension.
JTD Keywords: Electrospinning, Fibrinogen/polylactic acid hybrid nanofibres, Human adipose-derived stem cells
Serra, T., Ortiz-Hernandez, M., Engel, E., Planell, J. A., Navarro, M., (2014). Relevance of PEG in PLA-based blends for tissue engineering 3D-printed scaffolds Materials Science and Engineering: C 38, (1), 55-62
Achieving high quality 3D-printed structures requires establishing the right printing conditions. Finding processing conditions that satisfy both the fabrication process and the final required scaffold properties is crucial. This work stresses the importance of studying the outcome of the plasticizing effect of PEG on PLA-based blends used for the fabrication of 3D-direct-printed scaffolds for tissue engineering applications. For this, PLA/PEG blends with 5, 10 and 20% (w/w) of PEG and PLA/PEG/bioactive CaP glass composites were processed in the form of 3D rapid prototyping scaffolds. Surface analysis and differential scanning calorimetry revealed a rearrangement of polymer chains and a topography, wettability and elastic modulus increase of the studied surfaces as PEG was incorporated. Moreover, addition of 10 and 20% PEG led to non-uniform 3D structures with lower mechanical properties. In vitro degradation studies showed that the inclusion of PEG significantly accelerated the degradation rate of the material. Results indicated that the presence of PEG not only improves PLA processing but also leads to relevant surface, geometrical and structural changes including modulation of the degradation rate of PLA-based 3D printed scaffolds.
JTD Keywords: 3D-printing, Polylactic acid, Rapid prototyping, Scaffold, Surface characterization
Álvarez, Zaida, Mateos-Timoneda, Miguel A., Hyrossová, Petra, Castaño, Oscar, Planell, Josep A., Perales, José C., Engel, Elisabeth, Alcántara, Soledad, (2013). The effect of the composition of PLA films and lactate release on glial and neuronal maturation and the maintenance of the neuronal progenitor niche Biomaterials 34, (9), 2221-2233
To develop tissue engineering strategies useful for repairing damage in the central nervous system (CNS) it is essential to design scaffolds that emulate the NSC niche and its tight control of neural cell genesis, growth, and differentiation. In this study we tested two types of poly l/dl lactic acid (PLA95/5 and PLA70/30), a biodegradable material permissive for neural cell adhesion and growth, as materials for nerve regeneration. Both PLA were slightly hydrophobic and negatively charged but differed in crystallinity, stiffness and degradation rate. PLA95/5 films were highly crystalline, stiff (GPa), and did not degrade significantly in the one-month period analyzed in culture. In contrast, PLA70/30 films were more amorphous, softer (MPa) and degraded faster, releasing significant amounts of lactate into the culture medium. PLA70/30 performs better than PLA95/5 for primary cortical neural cell adhesion, proliferation and differentiation, maintaining the pools of neuronal and glial progenitor cells inÂ vitro. l-lactate in the medium recapitulated PLA70/30's maintenance of neuronal restricted progenitors but did not sustain bipotential or glial restricted progenitors in the cultures, as occurred when neural cells were grown on PLA70/30. Our results suggest that PLA70/30 may mimic some of the physical and biochemical characteristics of the NSC niche. Its mechanical and surface properties may act synergistically in the modulation of bipotential and glial restricted progenitor phenotypes, while it is l-lactate, either added to the medium or released by the film that drives the maintenance of neuronal restricted progenitor cell phenotypes.
JTD Keywords: Polylactic acid, Degradation, Neurons, Progenitors, Lactate, Glial cells, NSC niche
Serra, T., Planell, J. A., Navarro, M., (2013). High-resolution PLA-based composite scaffolds via 3-D printing technology Acta Biomaterialia 9, (3), 5521-5530
Fabrication of new biodegradable scaffolds that guide and stimulate tissue regeneration is still a major issue in tissue engineering approaches. Scaffolds that possess adequate biodegradability, pore size, interconnectivity, bioactivity and mechanical properties in accordance with the injured tissue are required. This work aimed to develop and characterize three-dimensional (3-D) scaffolds that fulfill the aforementioned requirements. For this, a nozzle-based rapid prototyping system was used to combine polylactic acid and a bioactive CaP glass to fabricate 3-D biodegradable scaffolds with two patterns (orthogonal and displaced double layer). Scanning electron microscopy and micro-computer tomography showed that 3-D scaffolds had completely interconnected porosity, uniform distribution of the glass particles, and a controlled and repetitive architecture. Surface properties were also assessed, showing that the incorporation of glass particles increased both the roughness and the hydrophilicity of the scaffolds. Mechanical tests indicated that compression strength is dependent on the scaffold geometry and the presence of glass. Preliminary cell response was studied with primary mesenchymal stem cells (MSC) and revealed that CaP glass improved cell adhesion. Overall, the results showed the suitability of the technique/materials combination to develop 3-D porous scaffolds and their initial biocompatibility, both being valuable characteristics for tissue engineering applications.
JTD Keywords: Rapid prototyping, Scaffold, Polylactic acid, Biodegradable, Composite
Navarro, M., Engel, E., Planell, J. A., Amaral, I., Barbosa, M., Ginebra, M. P., (2008). Surface characterization and cell response of a PLA/CaP glass biodegradable composite material Journal of Biomedical Materials Research - Part A , 85A, (2), 477-486
Bioabsorbable materials are of great interest for bone regeneration applications, since they are able to degrade gradually as new tissue is formed. In this work, a fully biodegradable composite material containing polylactic acid (PLA) and calcium phosphate (CaP) soluble glass particles has been characterized in terms of surface properties and cell response. Cell cultures were performed in direct contact with the materials and also with their extracts, and were evaluated using the MTT assay, alkaline phosphatase activity, and osteocalcin measurements. The CaP glass and PLA were used as reference materials. No significant differences were observed in cell proliferation with the extracts containing the degradation by-products of the three materials studied. A relation between the materials wettability and the material-cell interactions at the initial stages of contact was observed. The most hydrophilic material (CaP glass) presented the highest cell adhesion values as well as an earlier differentiation, followed by the PLA/glass material. The incorporation of glass particles into the PLA matrix increased surface roughness. SEM images showed that the heterogeneity of the composite material induced morphological changes in the cells cytoskeleton.
JTD Keywords: Glass, Polylactic acid, Surface analysis, Cell culture, In vitro test