Eduardo Antonio Della Pia

IT University of Copenhagen, København, Capital Region, Denmark

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Publications (23)114.25 Total impact

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    ABSTRACT: Amphipols (APols) are short amphipathic polymers that stabilize membrane proteins (MPs) in aqueous solutions. In the present study, A8-35, a polyacrylate-based APol, was grafted with hexahistidine tags (His6-tags). The synthesis and characterization of this novel functionalized APol, named HistAPol, are described. Its ability to immobilize MPs on nickel ion-bearing surfaces was tested using two complementary methods, immobilized metal affinity chromatography (IMAC) and surface plasmon resonance (SPR). Compared to a single His6-tag fused at one extremity of a MP, the presence of several His6-tags carried by the APol belt surrounding the transmembrane domain of a MP increases remarkably the affinity of the protein/APol complex for nickel ion-bearing SPR chips, whereas it does not show such a strong effect on an IMAC resin. HistAPol-mediated immobilization, which allows reversibility of the interaction and easy regeneration of the supports and dispenses with any genetic modification of the target protein, provides a promising alternative for attaching MPs onto solid supports while stabilizing them.
    No preview · Article · Oct 2015 · Biomacromolecules
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    Eduardo Antonio Della Pia · Karen L. Martinez
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    ABSTRACT: Single domain antibodies are recombinantly expressed functional antibodies devoid of light chains. These binding elements are derived from heavy chain antibodies found in camelids and offer several distinctive properties for applications in biotechnology such as small size, stability, solubility, and expression in high yields. In this study we demonstrated the potential of using single domain antibodies as capturing molecules in biosensing applications. Single domain antibodies raised against green fluorescent protein were anchored onto biosensor surfaces by using several immobilization strategies based on Ni2+:nitrilotriacetic acid-polyhistidine tag, antibody-antigen, biotin-streptavidin interactions and amine-coupling chemistry. The interaction with the specific target of the single domain antibodies was characterized by surface plasmon resonance. The immobilized single domain antibodies show high affinities for their antigens with KD = 3-6 nM and outperform other antibody partners as capturing molecules facilitating also the data analysis. Furthermore they offer high resistance and stability to a wide range of denaturing agents. These unique biophysical properties and the production of novel single domain antibodies against affinity tags make them particularly attractive for use in biosensing and diagnostic assays.
    Preview · Article · Mar 2015 · PLoS ONE
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    ABSTRACT: Cruciform-like molecules with two orthogonally placed π-conjugated systems have in recent years attracted significant interest for their potential use as molecular wires in Molecular Electronics. Here we present synthetic protocols for a large selection of cruciform molecules based on oligo(phenyleneethynylene) (OPE) and tetrathiafulvalene (TTF) scaffolds, end-capped with acetyl-protected thiolates as electrode anchoring groups. The molecules were subjected to a comprehensive study of their conducting properties as well as their photophysical and electrochemical properties in solution. The complex nature of the molecules and their possible binding in different configurations in junctions called for different techniques of conductance measurements, 1) conducting-probe atomic force microscopy (CP-AFM) measurements on self-assembled monolayers (SAMs), 2) mechanically controlled break-junction (MCBJ) measurements, and 3) scanning tunneling microscopy break-junction (STM-BJ) measurements. The CP-AFM measurements showed structure-property relationships: from SAMs of series of OPE3 and OPE5 cruciform molecules, the conductance of the SAM increased with the number of dithiafulvene (DTF) units (0, 1, 2) along the wire, and it increased when substituting two arylethynyl end-groups of the OPE3 backbone with two DTF units. The MCBJ and STM-BJ stud-ies on single molecules both showed that DTFs decreased the junction formation probability, but, in contrast, no significant influ-ence on the single-molecule conductance was observed. We suggest that the origins of the difference between SAM and single-molecule measurements lie in the nature of the molecule|electrode interface as well as in effects arising from molecular packing in the SAMs. This comprehensive study shows that for complex molecules care should be taken when directly comparing single-molecule measurements and measurements of SAMs and solid-state devices thereof.
    No preview · Article · Nov 2014 · Journal of the American Chemical Society
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    ABSTRACT: A series of mono- (MPTTF) and bis(pyrrolo)tetrathiafulvalene (BPTTF) derivatives tethered to one or two C60 moieties was synthesized and characterized. The synthetic strategy for these dumbbell-shaped compounds was based on a 1,3-dipolar cycloaddition reaction between aldehyde-functionalized MPTTF/BPTTF derivatives, two different tailor-made amino acids, and C60. Electronic communication between the MPTTF/BPTTF units and the C60 moieties was studied by a variety of techniques including cyclic voltammetry and absorption spectroscopy. These solution-based studies indicated no observable electronic communication between the MPTTF/BPTTF units and the C60 moieties. In addition, femtosecond and nanosecond transient absorption spectroscopy revealed, rather surprisingly, that no charge transfer from the MPTTF/BPTTF units to the C60 moieties takes place on excitation of the fullerene moiety. Finally, it was shown that the MPTTF–C60 and C60–BPTTF-C60 dyad and triad molecules formed self-assembled monolayers on a Au(111) surface by anchoring to C60.
    No preview · Article · Jul 2014 · Chemistry - A European Journal
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    ABSTRACT: Amphipols (APols) are specially designed amphipathic polymers that stabilize membrane proteins (MPs) in aqueous solutions in the absence of detergent. A8–35, a polyacrylate-based APol, has been grafted with an oligodeoxynucleotide (ODN). The synthesis, purification and properties of the resulting ‘OligAPol’ have been investigated. Grafting was performed by reacting an ODN carrying an amine-terminated arm with the carboxylates of A8–35. The use of OligAPol for trapping MPs and immobilizing them onto solid supports was tested using bacteriorhodopsin (BR) and the transmembrane domain of Escherichia coli outer membrane protein A (tOmpA) as model proteins. BR and OligAPol form water-soluble complexes in which BR remains in its native conformation. Hybridization of the ODN arm with a complementary ODN was not hindered by the assembly of OligAPol into particles, nor by its association with BR. BR/OligAPol and tOmpA/OligAPol complexes could be immobilized onto either magnetic beads or gold nanoparticles grafted with the complementary ODN, as shown by spectroscopic measurements, fluorescence microscopy and the binding of anti-BR and anti-tOmpA antibodies. OligAPols provide a novel, highly versatile approach to tagging MPs, without modifying them chemically nor genetically, for specific, reversible and targetable immobilization, e.g. for nanoscale applications.
    Preview · Article · Apr 2014 · Nucleic Acids Research
  • Eduardo Antonio Della Pia · Randi Westh Hansen · Manuela Zoonens · Karen L Martinez
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    ABSTRACT: Amphipols are amphipathic polymers that stabilize membrane proteins isolated from their native membrane. They have been functionalized with various chemical groups in the past years for protein labeling and protein immobilization. This large toolbox of functionalized amphipols combined with their interesting physico-chemical properties give opportunities to selectively add multiple functionalities to membrane proteins and to tune them according to the needs. This unique combination of properties makes them one of the most versatile strategies available today for exploiting membrane proteins onto surfaces for various applications in synthetic biology. This review summarizes the properties of functionalized amphipols suitable for synthetic biology approaches.
    No preview · Article · Apr 2014 · Journal of Membrane Biology
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    ABSTRACT: The influence of cross-conjugation vs. linear conjugation on the electronic communication between donor and acceptor groups in phenol(ate)–bridge–nitrobenzene chromophores was investigated by solution and gas-phase absorption spectroscopy, fluorescence spectroscopy, and quantum chemical calculations. The compounds studied include, among others, geminally and trans-substituted diethynylethenes prepared by stepwise Sonogashira cross-coupling reactions, and the cross-conjugated analogue of stilbene. A butadiyne-bridged donor–acceptor chromophore was prepared by an unsymmetrical Pd-catalysed coupling between a chloroalkyne and a terminal alkyne. While the linearly conjugated chromophores showed a strong and redshifted charge-transfer (CT) absorption maximum upon deprotonation in solution, a new redshifted absorption was either absent or present as a weak shoulder for the cross-conjugated derivatives. Calculations on the nonplanar 1,1-diaryl-substituted ethylene derivative revealed that the S0–S1 absorption has a very low oscillator strength due to insignificant coupling between the donor and acceptor ends. The energy of this CT absorption for a nonsolvated molecule is smaller than that of the linearly conjugated stilbene analogue by 0.4 eV. This result cannot directly be inferred from the solution studies. A gas-phase absorption spectrum of this chromophore was measured by action spectroscopy, which only revealed a higher-energy absorption band. Based on calculations, this band was assigned to a higher-lying π–π* transition. For the planar diethynylethene chromophores, cross-conjugation leads to a decrease of 0.3 eV in the excitation energy, according to the calculations. Finally, in contrast to the linearly conjugated chromophores, the cross-conjugated ones did not show any fluorescence, which may be due to deexcitation via the low-lying CT “dark” state.
    No preview · Article · Apr 2014 · European Journal of Organic Chemistry
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    ABSTRACT: Whether for fundamental biological research or for diagnostic and drug discovery applications, protein micro- and nano-arrays are attractive technologies because of their low sample consumption, high-throughput, and multiplexing capabilities. However, the arraying platforms developed so far are still not able to handle membrane proteins and specific methods to selectively immobilize these hydrophobic and fragile molecules are needed to understand their function and structural complexity. Here we integrate two technologies, electropolymerization and amphipols, to demonstrate the electrically addressable functionalization of micro- and nano-surfaces with membrane proteins. Gold surfaces are selectively modified by electrogeneration of a polymeric film in the presence of biotin where avidin-conjugates can be then selectively immobilized. The method is successfully applied to the preparation of protein multiplexed arrays by sequential electropolymerization and biomolecular functionalization steps. The surface density of the proteins bound to the electrodes can be easily tuned by adjusting the amount of biotin deposited during electropolymerization. Amphipols are specially designed amphipathic polymers that provide a straightforward method to stabilize and add functionalities to membrane proteins. Exploiting the strong affinity of biotin for streptavidin, we anchor distinct membrane proteins onto different electrodes via a biotin-tagged amphipol. Antibody-recognition events demonstrate that the proteins are stably immobilized and that the electrodeposition of polypyrrole films bearing biotin units is compatible with the proteins binding activity. Since polypyrrole films show good conductivity properties, the platform described here is particularly well suited to prepare electronically transduced bio-nanosensors.
    No preview · Article · Jan 2014 · ACS Nano
  • Eduardo Antonio Della Pia

    No preview · Conference Paper · Dec 2013
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    ABSTRACT: Dibenzo[bc,fg][1,4]dithiapentalene (1) has previously been prepared by an intramolecular nucleophilic aromatic substitution (SNAr) reaction of 9-fluorodibenzo[b,d]thiophen-1-thiol (X, Y ˭ S). Instead, subjecting 9-fluorodibenzo[b,d]benzofuran-1-ol (X, Y ˭ O) to similar reaction conditions provided a macrocycle (5), as a result of an intermolecular SNAr cyclization, rather than dibenzo[bc,fg][1,4]dioxapentalene (3). To shed further light on this reaction type, we here present an attempt to prepare the mixed (O,S) compound dibenzo[bc,fg][1,4]xathiapentalene (7) from 9-fluorodibenzo[b,d]thiophen-1-ol (11, X ˭ S, Y ˭ O). However, like a previous strategy to make this molecule, the attempt failed. We rationalize the results by a computational study of the reaction energetics and profiles of the SNAr reactions.
    No preview · Article · Dec 2013 · Journal of Sulfur Chemistry
  • Eduardo Antonio Della Pia · Anders Døssing · Kristine Kilså
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    ABSTRACT: The reaction of LnCl3 (Ln = Sm, Eu, Tb, Yb) with M(acacCN)3 (with M = Al, Cr, acacCN = 3-cyanoacetylacetonate) in ethanolic solution yields a series of novel 3d-4f heterodinuclear complexes [(acacCN)2M(μ-acacCN)LnCl3]. For M = Al the complexes display strong 4f–4f lanthanide-centered luminescence due to energy transfer from the triplet state of the ligand acacCN to the lanthanide. Photophysical measurements of the complexes with M = Cr show efficient sensitization of both Ln(III) and Cr(III) through ligand excitation at 77 K. Luminescence measurements indicate strong interactions between Ln(III) and Cr(III) and the degree of energy transfer between the two metals depends on the energy gap of the donor and acceptor levels.
    No preview · Article · Jan 2013 · Inorganica Chimica Acta

  • No preview · Article · Jan 2013 · Journal of Sulfur Chemistry
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    Eduardo Antonio Della Pia · Qijin Chi · J Emyr Macdonald · Jens Ulstrup · D Dafydd Jones · Martin Elliott
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    ABSTRACT: The electron transfer properties of proteins are normally measured as molecularly averaged ensembles. Through these and related measurements, proteins are widely regarded as macroscopically insulating materials. Using scanning tunnelling microscopy (STM), we present new measurements of the conductance through single-molecules of the electron transfer protein cytochrome b(562) in its native conformation, under pseudo-physiological conditions. This is achieved by thiol (SH) linker pairs at opposite ends of the molecule through protein engineering, resulting in defined covalent contact between a gold surface and a platinum-iridium STM tip. Two different orientations of the linkers were examined: a long-axis configuration (SH-LA) and a short-axis configuration (SH-SA). In each case, the molecular conductance could be 'gated' through electrochemical control of the heme redox state. Reproducible and remarkably high conductance was observed in this relatively complex electron transfer system, with single-molecule conductance values peaking around 18 nS and 12 nS for the SH-SA and SH-LA cytochrome b(562) molecules near zero electrochemical overpotential. This strongly points to the important role of the heme co-factor bound to the natively structured protein. We suggest that the two-step model of protein electron transfer in the STM geometry requires a multi-electron transfer to explain such a high conductance. The model also yields a low value for the reorganisation energy, implying that solvent reorganisation is largely absent.
    Full-text · Article · Oct 2012 · Nanoscale
  • Martina Cacciarini · Eduardo A. Della Pia · Mogens B. Nielsen
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    ABSTRACT: A new application of the dihydroazulene/vinylheptafulvene (DHA/VHF) system as a chemodosimeter for thiols is reported herein. A color change visible to the naked eye can be detected in acetonitrile/water (4:1) in the presence of cysteine and alkanethiols but not with other amino acids. The higher reactivity of DHA towards cysteine compared with VHF has been demonstrated. The easy synthesis of the main core and its versatility in terms of structural and physicochemical changes are essential elements for developing a new family of thiol-specific probes with higher selectivity and sensitivity than the reported prototype.
    No preview · Article · Oct 2012 · European Journal of Organic Chemistry
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    Eduardo Antonio Della Pia · Qijin Chi · Martin Elliott · J. Emyr Macdonald · Jens Ulstrup · D. Dafydd Jones
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    ABSTRACT: The biologically and nanotechnologically important heme protein cytochrome b(562) was reconstructed with zinc and copper porphyrins, leading to significant changes in the spectral, redox and electron transfer properties. The Cu form shifts the redox potential by +300 mV and exhibits high electron transfer, while the Zn form is redox inert.
    Full-text · Article · Sep 2012 · Chemical Communications
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    ABSTRACT: Intramolecular cyclization reactions of Green Fluorescent Protein chromophores (GFPc) containing an arylethynyl ortho-substituent at the phenol ring provide new aryl-substituted benzofuran derivatives of the GFPc. Some of these heteroaromatic compounds exhibit significantly enhanced fluorescence at red-shifted emission wavelengths relative to the parent GFPc structure.
    No preview · Article · Aug 2012 · RSC Advances
  • Eduardo A Della Pia · J Emyr Macdonald · Martin Elliott · D Dafydd Jones
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    ABSTRACT: An electron transfer protein is engineered with two thiol groups introduced at different positions in the molecular structure to allow robust binding to two gold electrodes. Atomic force microscopy and scanning tunneling microscopy single-molecule studies show that the engineered proteins: (1) bind to a gold electrode in defined orientation dictated by the thiol-pair utilised, and (2) have a higher conductance than the wild-type proteins indicating a more efficient electron transmission due to the strong gold-thiol contacts.
    No preview · Article · Aug 2012 · Small
  • Eduardo Antonio Della Pia · Martin Elliott · D Dafydd Jones · J Emyr Macdonald
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    ABSTRACT: The redox-active protein cytochrome b(562) has been engineered to introduce pairs of thiol groups in the form of cysteine residues at specified sites. Successful STM imaging of the molecules adsorbed on a gold surface indicated that one thiol group controls the orientation of the molecule and that the protein maintains its native form under the experimental conditions. Stable protein-gold STM tip electrical contact was directly observed to form via the second free thiol group in current-voltage and current-distance measurements. Proteins with thiol contacts positioned across the protein's short axis displayed a conductance of (3.48 ± 0.05) × 10(-5)G(0). However proteins with thiol groups placed along the long axis reproducibly yielded two distinct values of (1.95 ± 0.03) × 10(-5)G(0) and (3.57 ± 0.11) × 10(-5)G(0), suggesting that the placement of the asymmetrically located haem within the protein influences electron transfer. In contrast, the unengineered wild-type cytochrome b(562) had conductance values at least 1 order of magnitude less. Here we show that an electron transfer protein engineered to bind gold surfaces can be controllably oriented and electrically contacted to metallic electrodes, a prerequisite for potential integration into electronic circuits.
    No preview · Article · Nov 2011 · ACS Nano
  • Eduardo Antonio Della Pia

    No preview · Conference Paper · Jul 2011
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    Eduardo Antonio Della Pia · Qijin Chi · D Dafydd Jones · J Emyr Macdonald · Jens Ulstrup · Martin Elliott
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    ABSTRACT: Cytochrome b(562) was engineered to introduce a cysteine residue at a surface-exposed position to facilitate direct self-assembly on a Au(111) surface. The confined protein exhibited reversible and fast electron exchange with a gold substrate over a distance of 20 Å between the heme redox center and the gold surface, a clear indication that a long-range electron-transfer pathway is established. Electrochemical scanning tunneling microscopy was used to map electron transport features of the protein at the single-molecule level. Tunneling resonance was directly imaged and apparent molecular conductance was measured, which both show strong redox-gated effects. This study has addressed the first case of heme proteins and offered new perspectives in single-molecule bioelectronics.
    Full-text · Article · Jan 2011 · Nano Letters

Publication Stats

142 Citations
114.25 Total Impact Points


  • 2013-2015
    • IT University of Copenhagen
      København, Capital Region, Denmark
  • 2011-2012
    • Cardiff University
      • • School of Physics and Astronomy
      • • School of Biosciences
      Cardiff, Wales, United Kingdom