Staff member

Brenda Guadalupe Molina García

Staff member publications

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

Moghimiardekani, A., Molina, B. G., Enshaei, H., del Valle, L. J., Pérez-Madrigal, M. M., Estrany, F., Alemán, C., (2020). Semi-interpenetrated hydrogels-microfibers electroactive assemblies for release and real-time monitoring of drugs Macromolecular Bioscience 20, (7), 2000074

Simultaneous drug release and monitoring using a single polymeric platform represents a significant advance in the utilization of biomaterials for therapeutic use. Tracking drug release by real-time electrochemical detection using the same platform is a simple way to guide the dosage of the drug, improve the desired therapeutic effect, and reduce the adverse side effects. The platform developed in this work takes advantage of the flexibility and loading capacity of hydrogels, the mechanical strength of microfibers, and the capacity of conducting polymers to detect the redox properties of drugs. The engineered platform is prepared by assembling two spin-coated layers of poly-γ-glutamic acid hydrogel, loaded with poly(3,4-ethylenedioxythiophene) (PEDOT) microparticles, and separated by a electrospun layer of poly-ε-caprolactone microfibers. Loaded PEDOT microparticles are used as reaction nuclei for the polymerization of poly(hydroxymethyl-3,4-ethylenedioxythiophene) (PHMeDOT), that semi-interpenetrate the whole three layered system while forming a dense network of electrical conduction paths. After demonstrating its properties, the platform is loaded with levofloxacin and its release monitored externally by UV–vis spectroscopy and in situ by using the PHMeDOT network. In situ real-time electrochemical monitoring of the drug release from the engineered platform holds great promise for the development of multi-functional devices for advanced biomedical applications.

JTD Keywords: Biosensors, Conducting polymers, Drug delivery, Poly-γ-glutamic acid, Poly-ε-caprolactone

Molina, B. G., Bendrea, A. D., Lanzalaco, S., Franco, L., Cianga, L., del Valle, L. J., Puiggali, J., Turon, P., Armelin, E., Cianga, I., Alemán, C., (2020). Smart design for a flexible, functionalized and electroresponsive hybrid platform based on poly(3,4-ethylenedioxythiophene) derivatives to improve cell viability Journal of Materials Chemistry B 8, (38), 8864-8877

Development of smart functionalized materials for tissue engineering has attracted significant attention in recent years. In this work we have functionalized a free-standing film of isotactic polypropylene (i-PP), a synthetic polymer that is typically used for biomedical applications (e.g. fabrication of implants), for engineering a 3D all-polymer flexible interface that enhances cell proliferation by a factor of ca. three. A hierarchical construction process consisting of three steps was engineered as follows: (1) functionalization of i-PP by applying a plasma treatment, resulting in i-PPf; (2) i-PPf surface coating with a layer of polyhydroxymethy-3,4-ethylenedioxythiophene nanoparticles (PHMeEDOT NPs) by in situ chemical oxidative polymerization of HMeEDOT; and (3) deposition on the previously activated and PHMeEDOT NPs coated i-PP film (i-PPf/NP) of a graft conjugated copolymer, having a poly(3,4-ethylenedioxythiophene) (PEDOT) backbone, and randomly distributed short poly(ε-caprolactone) (PCL) side chains (PEDOT-g-PCL), as a coating layer of ∼9 μm in thickness. The properties of the resulting bioplatform, which can be defined as a robust macroscopic composite coated with a “molecular composite”, were investigated in detail, and both adhesion and proliferation of two human cell lines have been evaluated, as well. The results demonstrate that the incorporation of the PEDOT-g-PCL layer significantly improves cell attachment and cell growth not only when compared to i-PP but also with respect to the same platform coated with only PEDOT, constructed in a similar manner, as a control.


Molina, B. G., Cuesta, S., Besharatloo, H., Roa, J. J., Armelin, E., Alemán, C., (2019). Free-standing taradaic motors based on biocompatible nanoperforated poly(lactic acid) layers and electropolymerized poly(3,4-ethylenedioxythiophene) ACS Applied Materials and Interfaces 11, (32), 29427-29435

The electro-chemo-mechanical response of robust and flexible free-standing films made of three nanoperforated poly(lactic acid) (pPLA) layers separated by two anodically polymerized poly(3,4-ethylenedioxythiophene) (PEDOT) layers has been demonstrated. The mechanical and electrochemical properties of these films, which are provided by pPLA and PEDOT, respectively, have been studied by nanoindentation, cyclic voltammetry, and galvanostatic charge-discharge assays. The unprecedented combination of properties obtained for this system is appropriated for its utilization as a Faradaic motor, also named artificial muscle. Application of square potential waves has shown important bending movements in the films, which can be repeated for more than 500 cycles without damaging its mechanical integrity. Furthermore, the actuator is able to push a huge amount of mass, as it has been proved by increasing the mass of the passive pPLA up to 328% while keeping the mass of electroactive PEDOT unaltered.

JTD Keywords: Actuator, Artificial muscle, Conducting polymer, Nanoindentation

Molina, B. G., Cianga, L., Bendrea, A. D., Cianga, I., Alemán, C., Armelin, E., (2019). An amphiphilic, heterografted polythiophene copolymer containing biocompatible/biodegradable side chains for use as an (electro)active surface in biomedical applications Polymer Chemistry 10, (36), 5010-5022

Given that copolymers of complex topology and composition are at the forefront of multifunctional materials research, this work reports an amphiphilic random, heterografted copolymer of (A-g-B)m-ran-(A-g-C)n type, which was designed to work as an efficient and biocompatible electronic interface. The copolymer (henceforth denoted as PTh-g-(PEG-r-PCL) for simplification) was synthesized in a hierarchical fashion, having π-conjugated polythiophene (PTh) as the main chain and polar units, polyethylene glycol (PEG) and oligo-ε-caprolactone as side chains. The properties of the new copolymer, in solution and in solid state, were evaluated. The applied investigations showed that, due to its amphiphilic character and incompatibility of the side chains, PTh-g-(PEG-r-PCL) experiences microphase separation in solution and film states. By electronic microscopy techniques, two types of supramolecular structures were evidenced: (a) porous spherical particles and (b) rod-like structures. When deposited on carbon electrodes, the copolymer presented a good electroactivity and electrostability. Copolymer's biocompatibility studies, performed by using Cos-1 and Vero cell lines, demonstrated an excellent adhesion when compared with a bare steel electrode while a slight decrease of proliferation was registered, more pronounced for Vero cells, in spite of cell normal growth and morphology. Thanks to its excellent capability for electrochemically interfacing with aqueous electrolytes, the voltammetric oxidation of the NADH coenzyme at the PTh-g-(PEG-r-PCL) film-modified carbon electrode revealed that it can be used as a selective biosensor of this biomolecule, as well.


Molina, B. G., Del Valle, L. J., Turon, P., Armelin, E., Alemán, C., (2019). Electrochemical sensor for bacterial metabolism based on the detection of NADH by polythiophene nanoparticles Journal of Physical Chemistry C 123, (36), 22181-22190

Composite i-PP/PEDOT films made of isotactic polypropylene (i-PP), which is frequently used for the fabrication of implantable medical devices for internal use, and chemically synthesized poly(3,4-ethylendioxythiophene) (PEDOT) nanoparticles, which are electroactive and biocompatible, have been prepared and used to detect bacterial metabolism. After chemical and morphological characterization, the properties (interfacial, mechanical, thermal, and electrochemical) and biocompatibility of i-PP/PEDOT have been examined. Besides, carbon screen-printed electrodes coated with i-PP/PEDOT have been found to detect the growth of Gram-positive and Gram-negative bacteria through the oxidation of nicotinamide adenine dinucleotide (NADH), which arises from the metabolism of bacteria (i.e., respiration). Thus, as outer bacterial membranes are permeable to cytosolic NADH, this metabolite has been found to be an appropriate target for the detection of bacterial proliferation. In addition, the sensor does not respond to eukaryotic cells. This is because the major NADH pool in eukaryotic cells is located at the mitochondria and, therefore, the concentration of NADH in the medium is not high enough to be detected since the inner mitochondrial membrane is impermeable to NADH or NAD+.


Enshaei, H., Molina, B. G., del Valle, L. J., Estrany, F., Arnan, C., Puiggalí, J., Saperas, N., Alemán, C., (2019). Scaffolds for sustained release of ambroxol hydrochloride, a pharmacological chaperone that increases the activity of misfolded β-glucocerebrosidase. Macromolecular Bioscience 19, (8), 1900130

Ambroxol is a pharmacological chaperone (PC) for Gaucher disease that increases lysosomal activity of misfolded β-glucocerebrosidase (GCase) while displaying a safe toxicological profile. In this work, different poly(ε-caprolactone) (PCL)-based systems are developed to regulate the sustained release of small polar drugs in physiological environments. For this purpose, ambroxol is selected as test case since the encapsulation and release of PCs using polymeric scaffolds have not been explored yet. More specifically, ambroxol is successfully loaded in electrospun PCL microfibers, which are subsequently coated with additional PCL layers using dip-coating or spin-coating. The time needed to achieve 80% release of loaded ambroxol increases from ≈15 min for uncoated fibrous scaffolds to 3 days and 1 week for dip-coated and spin-coated systems, respectively. Furthermore, it is proven that the released drug maintains its bioactivity, protecting GCase against induced thermal denaturation.

JTD Keywords: Electrospinning, Gaucher's disease, Lysosomal storage disorders, Misfolding diseases, Poly(ε-caprolactone), Polyester, Release regulation