Photoactive Molecules, Photonics and Functional Materials

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Group Coordinator: António Maçanita

 

Group 8 includes now the 26 IDIs of the former Molecular Photochemistry & Photonic Materials (MPPM) group 8 of CQE-IST-UL,
the Optical & Multifunctional Materials (OM2) group of CQFM-IST-UL and the Molecular Biophysics (MB) group of CQB-FC-UL.
During the 2013-2017 period, the members of Group 8 have published 224 papers in international peer review journals (WoS),
filed 4 national and 4 international patents and raised ca. 2M euro funding in competitive calls for national and international
projects. Hopefully, the access to the common facilities resulting from this merging will improve the research capabilities of the
group.

The projected research topics for the 2018-2022 period are within the areas of (1) imaging and sensing, (2) theranostics, (3)
photonic materials, (4) energy and (5) biologic systems, as follows:

A - Imaging and Sensing: Hybrid Nanoparticles, Two Photon Absorption Systems, Gold Cluster Assemblies, Graphene Quantum

Dots and Graphene Nanohybrids, Fluorescent and Plasmonic Nanoantennas;

B - Theranostics: Mesoporous Hybrid Nanoparticles, Multifunctional Polymer Vectors, Polyelectrolyte Capsules, Magnetic Core-
Shell Nanoparticles;

C - Photonic Materials: Bulk Photonic Glasses and Glass Ceramics, Multilayer Photonic Glasses and 1-D Photonic Crystal Films;

D - Energy: Hybrid Metal Nanostructures, Organic Charge-Transfer Interfaces, Photonic Crystal-Assisted Frequency Conversion
Phosphor Layers, Molecules and Conjugated Polymers for Electroluminescence and Photovoltaic Conversion;

E - Biological systems: Anthocyanins, Organization of Biomembranes, Interactions Drug-Biomolecules, Complex Biomimetic Lipid
Bilayers.

Several of the above topics will be developed in cooperation with other groups of CQE (e. g., Groups 2, 4, 5 and 7) as before,
hopefully solving both scientific and societal problems, related to new materials, energy/environment and biomedicine, in
alignment with the strategic objectives of CQE represented by its Thematic Lines.

 

PLASMONIC FLUORESCENCE IN CORE-POLYELECTROLYTE-SHELL ASSEMBLIES
Gold nanoparticles were incorporated into a polyelectrolyte-shell type of assembly with a coating lipid vesicle encapsulating a
phthalocyanine dye. The supramolecular construct having polyelectrolyte layers as spacers between the particles surface and the
phthalocyanine was designed to control the emission enhancement through the plasmonic antenna effect. Large emission
enhancements, of about 3 orders of magnitude, for an optimum number of 13 to 15 polyelectrolyte layers, were attributed to hotspots
formed by the clustering of gold nanoparticles during the layer-by-layer deposition of polyelectrolytes. Fluorescence lifetime
imaging microscopy enabled to correlate those enhancements with shortening of emission lifetimes, as expected from the
plasmonic effect of radiative and nonradiative rates. The polyelectrolyte-assembled clusters of gold nanoparticles are of
submicrometric size, making these nano-objects promising for enhanced imaging or biosensing applications.


COFRE PROJECT: PHOTONIC CRYSTAL-ASSISTED FREQUENCY CONVERSION PHOSPHOR LAYERS FOR ENERGY
APPLICATIONS.
Clean energy production from renewable sources and energy efficiency are two critical issues for which the development of new
technologies is essential. An example of the former is photovoltaic solar energy conversion, whose efficiency still needs to be
improved. On the other hand, white light generation based on light emitting diode (LED)/a phosphor combination is an example of
the latter. The first half of the COFRE project has been aimed at reducing thermalization and transparency solar cell losses
through a combination of up-conversion and down-conversion phosphor coatings on the SCs. Some remarkable results have
already been obtained, as attested by 3 invited talks in international conferences and 3 papers submitted to international refereed
journals (two of them already accepted).


FLUORESCENT HYBRID NANOPARTICLES FOR THERANOSTIC APPLICATIONS.
Synthesis of perylenediimide (PDI) dyes for incorporation in silica nanomaterials with high brightness, enhanced photostability,
and tunable in the visible and NIR. Nanoparticles with a silica core containing covalently-bonded PDI and a polymer shell yielded
novel high performance nanostructured photoactive coatings. From these, we developed new fluorescence silica NPs with a
biocompatible polymer shell decorated with tumor-targeting groups for bioimaging. The system was further tuned for controlled
delivery by introducing mesopores in the silica core to accommodate large cargo payloads, and coating with a temperatureresponsive
biocompatible polymer. This system works as a nanopumping temperature-activated device to release cargo ondemand,
with excellent perspectives for theranostic applications. The work originated 6 papers, a national and an international
patent, and is being further developed for delivery across the blood-brain barrier and in bone regeneration.

SELECTED PUBLICATIONS

  1. Costa,; Galvão, A. M.; Di Paolo, R.E.; Freitas, A. A.; Lima, J.; Quina, F.H.; Maçanita, A. L. “Photochemistry of the Hemiketal form of anthocyanins and its potential role in plant protection from UV-B radiation”, Tetrahedron (Special issue: Chemistry in the Vine and Wine Sciences), 71, 3157-3162, 2015, DOI: 10.1016/j.tet.2014.06.092.
  2. Seixas de Melo, J. S.; Maçanita, A.L. “Unveiling the Eigen-Weller ion pair from the excited state proton transfer kinetics of 3-chloro-4-methyl-7-hydroxycoumarin”, Phys. Chem B (Special issue: Photoinduced Proton Transfer in Chemistry and Biology) 2015, 119, 2604−2610, DOI: 10.1021/jp508782h.
  3. Saraiva, A.; Jorge, C. D.;Santos, H.; Maçanita, A. L., “Earliest Events in α-Synuclein Fibrillation Probed with the Fluorescence of Intrinsic Tyrosines” J. Photochem. Photobiology B, 2016, 154, 16-23,DOI:10.1016/j.jphotobiol.2015.11.006.
  4. Rui M. Almeida, Himanshu Jain, Carlo G. Pantano, “Low-energy ion scattering spectroscopy of modified silicate glasses”, Am. Ceram. Soc. 99 (2016) 1259 – 1265.
  5. Tiago V. Ribeiro, Luís F. Santos, M. Clara Gonçalves, Rui M. Almeida, “Heavily Yb-doped silicate glass thick films”, Sol-Gel Sci. Technol. (DOI 10.1007/s10971-016-4071-7).
  6. R. Faria, M. Margarida Cruz, M. C. Gonçalves, Alexandra Carvalho,Gabriel Feio, M. B. F. Martins, “Synthesis and Characterization of Magnetoliposomes for MRI contrast enhancement“, International Journal of Pharmaceutics 446 (2013) 183 – 190.
  7. Khatua, S; Paulo, PMR; Yuan, H; Gupta, A; Zijlstra, P; Orrit, M,Resonant Plasmonic Enhancement of Single-Molecule Fluorescence by Individual Gold Nanorods, ACS Nano 2014, 8, 4440-4449.
  8. M. Andrade, C. J. Bueno-Alejo, V. V. Serra, J. M. M. Rodrigues, M. G. P. M. S. Neves, A. S. Viana and S. M. B. Costa, “Anchoring of Gold Nanoparticles on Graphene Oxide and Noncovalent Interactions with Porphyrinoids”, ChemNanoMat, 2015, 1, 502 – 510,DOI: 10.1002/cnma.201500133
  1. R. Teixeira, PMR. Paulo and S M B Costa, “Gold Nanoparticles in Core−Polyelectrolyte−Shell Assemblies Promote Large Enhancements of Phthalocyanine Fluorescence”, J. Phys. Chem. C, 119 (2015) 21612-21619 ;DOI: 10.1039/c4cp05373g
  2. V. Vaz Serra, R.Teixeira, S M. Andrade, S.M.B.Costa, “Design of polyelectrolyte core-shells   with DNA to control TMPyP binding”, Colloids Surf B: Biointerfaces.(2016)146,127-135, DOI:10.1016/j.colsurfb.2016.05.047.