Ana Testera - Academia.edu (original) (raw)

Papers by Ana Testera

Introduction The elastin-like recombinamers (ELRs) are recombinant protein-based polymers derived... more Introduction The elastin-like recombinamers (ELRs) are recombinant protein-based polymers derived from the repetition of selected amino acid domains of ECM proteins with the aim of reproducing their physiological and mechanical features. The proteinaceous nature of ELRs allows add specific functionalities and bioactivities by the use of genetic engineering tools. Our group is working in the design and biosynthesis of ELR to act as advanced materials for tissue engineering scaffolds. We verified herein ELRs feasibility to produce 2D and 3D artificial ECM scaffolds, their capacity to accommodate different class of cells and their bio-processability.

International Journal of Biological Macromolecules, 2019

Herein we present a novel one-pot method for the chemical modification of elastin-like recombinam... more Herein we present a novel one-pot method for the chemical modification of elastin-like recombinamers (ELRs) in a mild and efficient manner involving enzymatic catalysis with Candida antarctica lipase B. The introduction of different functionalities into such ELRs could open up new possibilities for the development of advanced biomaterials for regenerative medicine and, specifically, for controlled drug delivery given their additional ability to respond to stimuli other than pH or temperature, such as glucose concentration or electromagnetic radiation. Candida antarctica lipase B immobilized on a macroporous acrylic resin (Novozym 435) was used to enzymatically couple different aminated substrates to a recombinamer containing carboxylic groups along its amino acid chain by way of an amidation reaction. A preliminary study of the kinetics of this amidation in response to different reaction conditions, such as solvent, temperature or reagent ratio, was carried out using a phenylazobenzene derivative (azo-NH 2) as a model. The optimal amidation conditions were used to couple other amine reagents, such as phenylboronic acid (FB-NH 2) or polyethylene glycol (PEG-NH 2), thus allowing us to obtain photoresponsive, glucose-responsive or PEGylated ELRs that could potentially be useful as sensors in devices for controlled drug delivery.

Biomaterials and Biomedical Engineering, 2015

A bioactive and multifunctional elastin-like polymer (ELP) was produced by genetic engineering te... more A bioactive and multifunctional elastin-like polymer (ELP) was produced by genetic engineering techniques to develop new artificial matrices with the ability to mimic the extracellular matrix (ECM). The basic composition of this ELP is a thermo- and pH-sensitive elastin pentapeptide which has been enriched with RGD-containing domains, the RGD loop of fibronectin, for recognition by integrin receptors on their sequence to promote efficient cell attachment. Hydrogels of this RGD-containing polymer were obtained by crosslinking with hexamethylene diisocyanate, a lysine-targeted crosslinker. These materials retain the "smart" nature and temperature-responsive character, and the desired mechanical behavior of the elastin-like polymer family. The influence of the degree of crosslinking on the morphology and properties of the matrices were tested by calorimetric techniques and scanning electron microscopy (SEM). Their mechanical behavior was studied by dynamical mechanical analysis (DMA). These results show the potential of these materials in biomedical applications, especially in the development of smart systems for tissue engineering.

Biomaterials from Nature for Advanced Devices and Therapies, 2016

Journal of Tissue Engineering and Regenerative Medicine, Sep 30, 2013

Natural-Based Polymers for Biomedical Applications, 2008

Publisher Summary Modern biomaterials science is characterized by a growing emphasis on identific... more Publisher Summary Modern biomaterials science is characterized by a growing emphasis on identification of specific design parameters that are critical to performance, and by a growing appreciation of the need to integrate biomaterials design with new insights emerging from studies of cell-matrix interactions, cellular signaling processes, and developmental and systems biology. Elastin-Like Polymers (ELPs) are non-natural polypeptides composed of repeating sequences. They have their origin in the repeating sequences found in the mammalian elastic protein elastin that confers elasticity to structures such as skin and blood vessels. The importance of these polymers reside in the fact that they show a versatile and ample range of interesting properties that are difficult to find together in other materials, and that goes beyond their simple mechanical performance. Certainly, ELPs show a set of properties that places them in an excellent position towards designing advanced polymers for many different applications, including the most cutting edge biomedical and nanobiotechnological uses. Regarding their properties, some of their main characteristics are derived from the natural protein on which they are based.

Taubert/Biomaterials Surface Science, 2013

ABSTRACT

Journal of Materials Science: Materials in Medicine, 2015

Elastin-like recombinamer click gels (ELR-CGs) for biomedical applications, such as drug delivery... more Elastin-like recombinamer click gels (ELR-CGs) for biomedical applications, such as drug delivery or tissue engineering, have been developed by taking advantage of the click reaction (CuAAC) in the absence of traditional crosslinking agents. ELRs are functionalized with alkyne and azide groups using conventional chemical techniques to introduce the reactivity required to carry out the 1,3-dipolar cycloaddition under mild biocompatible conditions, with no toxic by-products and in short reaction times. Hydrogels with moduli in the range 1,000-10,000 Pa have been synthesized, characterized, and tested in vitro against several cell types. The cells embedded into ELR-CGs possessed high viability and proliferation rate. The mechanical properties, porosity and swelling of the resulting ELR-CGs can easily be tuned by adjusting the ELR concentration. We also show that it is possible to replicate different patterns on the hydrogel surface, thus allowing the use of this type of hydrogel to improve applications that require cell guidance or even differentiation depending on the surface topography.

Polymer, 2014

Abstract Herein we present a study of the effect of the addition of NaCl on the size and shape of... more Abstract Herein we present a study of the effect of the addition of NaCl on the size and shape of thermally driven elastin-like block co-recombinamer (ELbcRs) self-assembled nano-objects. Many researchers are currently using NaCl to tune the transition temperature ( T t ) of elastin-like recombinamers (ELRs). However, this method is used without a complete understanding of the potential changes in the self-assembly process that might result. Therefore, although salts other than NaCl are used for comparison in this study, the main effort is directed towards the effect of NaCl as this salt is widely and routinely used to control T t in ELR purification protocols and their applications. Dynamic light scattering (DLS) was used to follow the formation and determine the size of the nano-objects assembled, whereas static light scattering (SLS) was performed to study the molecular weight and gyration radius of the aggregates. Cryo-transmission electron microscopy (Cryo-TEM) was used to corroborate the data obtained by light scattering. These results support the use of NaCl as a highly interesting means of controlling the dimensions of ELbcR-based self-assembled nanoparticles in aqueous solution.

Tissue Engineering Part A, 2008

The Journal of Physical Chemistry B, 2013

Tetrahedron, 2004

Biochemical syntheses Biochemical syntheses O 0035 Preparation of N-Unsubstituted β-Ketoamides by... more Biochemical syntheses Biochemical syntheses O 0035 Preparation of N-Unsubstituted β-Ketoamides by Rhodococcus Rhodochrous-Catalyzed Hydration of β-Ketonitriles.-For the first time, β-ketonitriles are transformed into their corresponding β-ketoamides by bacterial hydration using diethyl phosphoramidate as an amidase inhibitor. The resulting β-ketoamides exist as a keto-enol mixture whose composition depends on the substituents and varies with solvent polarity.-(GOTOR*, V.;

Soft Matter, 2011

... Monika Golonkaa, Maria Bulwanb, Maria Nowakowskab, Ana María Testeraa, José Carlos Rodríguez-... more ... Monika Golonkaa, Maria Bulwanb, Maria Nowakowskab, Ana María Testeraa, José Carlos Rodríguez-Cabello*a and Szczepan Zapotoczny*b. ... The substrates were carefully cleaned in piranha solution (a mixture of H 2 SO 4 and H 2 O 2 in a 1 : 3 ratio) prior to usage. ...

Progress in Polymer Science, 2005

In spite of the enormous possibilities presented by macromolecules for the development of advance... more In spite of the enormous possibilities presented by macromolecules for the development of advanced materials with increased functionality, the achievement of functionality is often limited by the randomness associated with polymer synthesis and the exponential increase in technical difficulties encountered in attaining a desired degree of complexity in the molecular design. This paper describes an increasingly important approach to the design of complex and highly functional macromolecules, i.e. the genetic engineering of protein-based macromolecules. The exploitation of the efficient machinery of protein synthesis in living cells opens a route to precisely defined and complex macromolecules. A series of molecular designs with increasing complexity are presented to show how this controlled increase yields materials with increasingly selective and sophisticated multifunctionality. The simplest designs already show interesting mechanical properties, but the adequate introduction of given chemical functions along the polymer chain provides an opportunity to expand the range of properties to smart behavior and self-assembly. Finally, examples are given where the molecular designs further incorporate selected bioactivities in order to develop materials for the most cutting-edge applications in f biomedicine and nanobiotechnology.

Nanoscale Research Letters, 2009

Electrostatic self-assembly was used to fabricate new smart multi-layer coatings, using a recombi... more Electrostatic self-assembly was used to fabricate new smart multi-layer coatings, using a recombinant elastin-like polymer (ELP) and chitosan as the counterion macromolecule. The ELP was bioproduced, purified and its purity and expected molecular weight were assessed. Aggregate size measurements, obtained by light scattering of dissolved ELP, were performed as a function of temperature and pH to assess the smart properties of the polymer. The build-up of multi-layered films containing ELP and chitosan, using a layer-by-layer methodology, was followed by quartz-crystal microbalance with dissipation monitoring. Atomic force microscopy analysis permitted to demonstrate that the topography of the multi-layered films could respond to temperature. This work opens new possibilities for the use of ELPs in the fabrication of biodegradable smart coatings and films, offering new platforms in biotechnology and in the biomedical area.

Macromolecules, 2004

The pH-responsive elastin-like polymers, [(PGVGV) 2-(PGEGV)-(PGVGV)2]n with n) 5, 9, 15, 30, 45, ... more The pH-responsive elastin-like polymers, [(PGVGV) 2-(PGEGV)-(PGVGV)2]n with n) 5, 9, 15, 30, 45, were obtained using genetic engineering and microbial protein expression. These were intended to study the effects of the molecular weight (MW) on the properties of their inverse temperature transition (ITT) and its dependence on pH. As a result, the transition temperature decreased and the transition enthalpy increased as the molecular weight increased, especially for the lowest MWs. More strikingly, the apparent pK a for the γ-carboxyl residue of the glutamic acid also depends on MW. The apparent pKa is lower for lower MWs. In summary, the modification in the ITT caused by changes in MW is similar to the one caused by changes in the mean polarity of the polymer as described in the literature. A reduction in the molecular weight is equivalent to a decrease in the mean hydrophobicity of the polymer.

Macromolecular Rapid Communications, 2010

Here, we describe a procedure to manufacture smart hybrid probes that exhibit tunable optical pro... more Here, we describe a procedure to manufacture smart hybrid probes that exhibit tunable optical properties as a function of multiple environmental variations. Initially, we achieved a one-pot synthesis of gold-PREP (photo-responsive elastin-like polymer) conjugate Gold-AzoGlu15 via reduction of auric acid in the presence of PREP AzoGlu15. Outstandingly, Gold-AzoGlu15 exhibited pH and temperature sensitiveness. However, Gold-AzoGlu15 was not UV-vis sensitive. We noticed that photo-isomerisation of azobenzene moieties in Gold-AzoGlu15 could not be detected by UV-vis spectroscopy. In a subsequent step, we explored the use of cyclodextrins and the formation of alkanethiol mixed-monolayers over mother Gold-Azo-Glu15 by thiol-place exchange reactions in order to decouple photo-isomerisation of azobenzene from the bulk phase absorption. In this sense we achieved the synthesis of b-cyclodextrin capped Gold-CD-AzoGlu15. Notable was that cis-trans photo-conversion of azobenzene groups in Gold-CD-AzoGlu15 could be successfully detected. Finally, we present the optical properties exhibited by multi-sensitive probe Gold-CD-AzoGlu15 as a function of pH, temperature and UV-vis irradiation. We think that gold-PREP hybrids could be of great interest in the design of multi-functional chromophore-metal nanocomposites that operate in aqueous media for the development of multi-stimuli sensitive detectors for biosensing applications.

Journal of Materials Science: Materials in Medicine, 2004

Genetic engineering techniques were used to design and biosynthesise an extracellular matrix (ECM... more Genetic engineering techniques were used to design and biosynthesise an extracellular matrix (ECM) analogue. This was designed with a well-de®ned molecular architecture comprising different functional domains. The structural base is a elastin-derived repeating unit, which confers an adequate elastic characteristic. Some of these elastin domains have been modi®ed to contain lysine; this amino acid can be used for crosslinking purposes. The polymer also contain periodically spaced ®bronectin CS5 domains enclosing the well-known cell attachment sequence REDV. Finally, the polymer has target sequences for proteolitic action. These sequences are those found in the natural elastin and are introduced to help in the bioabsorption of the polymer. In addition, these proteolitic sequences were chosen in a way that, after proteolitic action, the released fragments will be bioactive. These fragments are expected to promote cell proliferation activity, angiogenesis and other bioactivities of interest for tissue growing, repairing and healing. After puri®cation, the resulting polymers proved to be of high purity and correct sequence. Glutaraldehyde has shown to be a cross-linking agent for this polymer, yielding insoluble hydrogel matrices. This work is framed in a long term project aimed to exploit the power of genetic engineering for the design and bioproduction of complex ECM analogues showing the rich complexity and multi (bio)functionality of the natural matrix.