CLL (Coimbra, Portugal)

Chemistry Department, University of Coimbra

CLL aims to promote and support the use of lasers in the study of the interactions between radiation and matter at the molecular level. Specialized on photochemical, photophysical and spectroscopic studies, from the infrared through the ultraviolet, covering timescales from femtoseconds at room temperatures to very slow processes at cryogenic temperatures.

Website: www.uc.pt/en/uid/laserlab

Contact:
Luís Arnaut
Carlos Serpa

Research highlights

Research at CLL covers a wide range of subjects in the fields of Photophysics, Photochemistry, Photobiology, Photofunctional Materials and conservation of Art. Success stories of research at CLL include a photosensitizer for photodynamic therapy in clinical trials, light-to pressure transducers marketed for skin permeabilization, advances is organic polymeric and inorganic photovoltaics, matrix isolation spectroscopy, hot vibrational chemistry, and art conservation.

Industrial Collaboration

Ongoing projects with LaserLeap Tech, SA, “Photoactive antimicrobial materials for indwelling medical devices”, Globalstars Brazil 2022-17848//GS Brazil 2022 (Oct 2023 – Oct 2026), and with 3 industry consortia, “PRODUTEC” (PPR, C644912598-00000021), GREENAUTO (PPR, 02/C05-i01/2022) and RESETFINAS (PRR, C12 -TC-12-i01 -2021).

Generation of broadband, high-intensity photoacoustic waves at low laser fluences

Using graphene-decorated gold nanoparticles and picosecond lasers with 50 mJ/cm2 fluences, it was possible to generate photoacoustic waves with peak pressures ~20 bar and bandwidth of 85 MHz at –6 dB, that can be used in miniaturized medical devices for high-resolution imaging. {Nano Ene. 131, 110236 (2024).

Photoinactivation of Gram-positive and Gram-negative biofilms in non-toxic conditions for human cells

Combining a photosensitizer developed in the group with potassium iodide, it was possible to eradicate bacteria present in biofilms without toxicity for human cells, and to cure infections induced in the back of mice. [ACS Infect. Dis. 10, 3368 (2024)]

Increase cell uptake of macromolecules

Macromolecules cannot cross cell membranes by passive diffusion, and the endocytosis route leads to their degradation. It was shown how amphiphilicity can increase cell uptake and a new mechanism is disclosed. [J. Am. Chem. Soc, 144, 15252 (2022)]

Understanding ultrafast photoinduced phase transitions in crystals

The drastic shape deformation that accompanies the structural phase transitions offers great potential for their applications as actuators and sensors. It was shown that two low-frequency vibrational–librational modes are directly related to the order parameter that describes this phase transition, which is supported by experimental Raman spectroscopy studies [Proc. Nat. Acad. Sci USA; 212, e2408366121]

Sensitization of surface-anchored organic dyes on perovskite nanocrystals

The mechanism behind the energy/charge transfer between perovskite nanocrystals and BODIPY dyes, under visible light, was investigated. It was shown that a charge-mediated TET mechanism outcompetes the hot exciton thermalization and FRET processes with implications in its use in photocatalysis. [J. Am. Chem. Soc. 146, 14479 (2024)]

Expertise

CLL is:

  • a leader in time-resolved photo-acoustics
  • a leader in matrix isolation spectroscopy, photochemistry and solid-state hot vibrational chemistry
  • a reference laboratory for time-resolved single photon counting and fluorescence up-conversion
  • equipped for state-of-the-art femtosecond transient absorption measurements with NIR/VIS/NIR detection
  • an expert in broadband molecular rotational resonance (MRR) spectroscopy
  • a unique facility integrating fs/ps/ns measurements of transients in solutions, films, supercritical fluids, cultured cells flow cytometry, and low temperature matrices. CLL recently installed photoacoustic tomography in an associated animal facility, a Two-Dimensional Infrared spectrometer (2D-IR) and a broadband fluorescence up-conversion spectrometer.
Services for industry
Medical Technologies

Technology development and transfer, followed by testing and training: Development of light-to-pressure transducers, transfer of the technology to a biotech start-up, demonstration that the pressure pulses permeabilize the skin and enhance dermal drug delivery.

Drug development

Technology development and transfer, followed by testing and training: Development of a new photosensitizer for photodynamic therapy, transfer of the technologyto a pharamceutical company, demonstration of safety and efficacy in vitro and in vivo, support of a Phase I/IIa clinical trial.

Manufacturing

Materials development, Materials processing, Tech transfer: Laser induced thermal synthesis, Laser ablation for nanomaterials production and preparation of materials.

Equipment offered to external users

Raman and infrared (IR) spectroscopies
  • for vibrational studies, with micro-sampling techniques available, which include Raman and IR mapping/imaging
Specialised IR spectroscopy
  • for low temperature matrix-isolation research, for characterization of short-living species, evaluation of photochemical mechanistic aspect of organic chemistry reactions, and studies of intramolecular energy redistribution.
Chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy
  • coupled with supersonic jet expansions sampling, for structural studies, including of complex mixtures.
Photo-acoustics
  • Time-resolved photoacoustic calorimetry, for monitoring non-radiative molecular processes following pulsed photo-excitation
  • Photoacoustic tomography coupled with ultrasound imaging and integrated in an animal facility with access to a wide range of animal models
 Transient absorption spectroscopy (fs, ps, ns, µs)
  • ns laser flash photolysis and fs pump-probe spectroscopy set-ups for UV, Vis and NIR regions, for detection of transient species in different experimental conditions
Time-resolved fluorescence (fs, ps, ns)
  • Fluorescence up-conversion and time correlated single photon counting techniques for measurement of fluorescence lifetimes in different experimental conditions
Fluorescence and phosphorescence spectroscopies
  • for studies in different phases, including micro-absorption spectroscopy and solid-state fluorescence quantum yield determinations.
Fluorescence Lifetime Imaging Microscopy (FLIM)
  • FLIM is a molecular fluorescence lifetime-based microscopy technique used to map the spatial distribution of cells and materials. Fluorescence is sensitive to the environment, which provides the advantages of the FLIM technique together with molecular contrast given by the endogenous/exogenous fluorophores.
In vitro and in vivo studies
  • Fully equipped cell culture labs, with a large collection of immortalized cancer and normal cell lines, including methods for photo-activation and analysis of biological processes, including flow cytometry and Western blot
  • Accompanied access, with FELASA-accredited researchers, to an animal facility with imaging technologies are available (photoacoustic tomography, magnetic resonance imaging)