Vincent Sol

Triazinyl Porphyrin-Based Photoactive Cotton Fabrics: Preparation, Characterization, and Antibacterial Activity

In the present work, we report on the synthesis of cellulose cotton fibers bearing different types of photosensitizers with the aim to prepare new efficient polymeric materials for antimicrobial applications. Anionic, neutral, and cationic amino porphyrins have been covalently grafted on cotton fabric, without previous chemical modification of the cellulosic support, using a 1,3,5-triazine derivative as the linker. The obtained porphyrin-grafted cotton fabrics were characterized by infrared (ATR-FTIR), diffuse reflectance UV-vis (DRUV) spectroscopies, and thermogravimetric analysis (TGA) to confirm the triazine linkage. Antimicrobial activity of porphyrin-cellulose materials was tested under visible light irradiation against Staphylococcus aureus and Escherichia coli . The results showed excellent activity on the Gram-positive bacterium, showing structure-activity relationship, although no photodamage of the Gram-negative microorganism was recorded. A mechanism of bacterial inactivation by photosensitive surfaces is proposed.

Porphyrin-functionalized mesoporous organosilica nanoparticles for two-photon imaging of cancer cells and drug delivery

The synthesis of a zinc porphyrin derivative possessing eight triethoxysilyl groups was performed through a CuAAC-click reaction. This porphyrin was covalently entrapped in ethenylene-bridged mesoporous organosilica nanoparticles which efficiently allowed performing doxorubicin delivery and two-photon imaging of breast cancer cells.

Chlorin-PEI-labeled cellulose nanocrystals: synthesis, characterization and potential application in PDT.

This Letter reports the synthesis and characterization of a new series of water-stable and soluble photosensitizers (PS-CNCs) composed of cellulose nanocrystals (CNCs) bearing polyaminated chlorin p6. With a view to improve cancer cell targeting, these photosensitizers were assayed for their antitumor activity against HaCat cell line. IC(50) values fell within the nanomolar-range, making these photosensitizers promising for further in vitro and in vivo investigations.

Synthesis of tetraglucosyl- and tetrapolyamine-tetrabenzoporphyrin conjugates for an application in PDT.

This paper reports the synthesis and characterization of a new class of tetrabenzoporphyrins bearing glucosyl or polyamine units on meso positions to improve the targeting of cancer cells. Photocytotoxic activity of these photosensitizers was tested on cell lines HaCaT and MCF-7 and compared to Photofrin II.

Synthesis and photobiocidal properties of cationic porphyrin-grafted paper.

We report on the synthesis of cellulose paper bearing a cationic porphyrin, designed for antimicrobial applications. Tricationic porphyrin has been covalently grafted on paper, without previous chemical modification of the cellulosic support, using 1,3,5-triazine derivative as linker. The obtained porphyrin-grafted paper was characterized by infrared (ATR-FTIR), UV-visible and diffuse reflectance UV-vis (DRUV) spectroscopies to confirm the triazine linkage. Thermogravimetric analysis (TGA) was used to investigate thermal properties of grafted paper. Antimicrobial activity of porphyrin-cellulose material was tested under visible light irradiation against Staphylococcus aureus and Escherichia coli. The two bacterial strains deposited on the resulting photosensitizing filter paper are efficiently killed after illumination.

UV and visible light screening by individual sporopollenin exines derived from Lycopodium clavatum (club moss) and Ambrosia trifida (giant ragweed).

We have investigated the UV-visible light transmission of three types of micrometre-sized sporopollenin exine shells, two derived from Lycopodium clavatum (club moss) spores and one from Ambrosia trifida (giant ragweed) pollen. We have used spectrophotometer measurements of partial monolayers of exines and microscope absorbance imaging to derive the light transmission properties of individual exines. Measurements have been made for exines in air when light transmission losses are due to a combination of absorption, reflection and scattering processes and for exines dispersed in a liquid for which the refractive index (RI) is approximately equal to the RI of the exine such that reflection and scattering effects are negligible. Overall, it found that the light transmission of a single exine wall is approximately 50%. This value of the transmission is due mainly to light absorption, is similar for the three exines studied here and varies only slightly with light wavelength over the range 200-900 nm.

Development of curcumin–cyclodextrin/cellulose nanocrystals complexes: New anticancer drug delivery systems

The synthesis of curcumin-cyclodextrin/cellulose nanocrystals (CNCx) nano complexes was performed. CNCx were functionalized by ionic association with cationic β-cyclodextrin (CD) and CD/CNCx complexes were used to encapsulate curcumin. Preliminary in vitro results showed that the resulting curcumin-CD/CNCx complexes exerted antiproliferative effect on colorectal and prostatic cancer cell lines, with IC50s lower than that of curcumin alone.

Photostability and photobactericidal properties of porphyrin-layered double hydroxide–polyurethane composite films

The photostability and photobactericidal properties of PdTPPC (Pd(ii)-5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin)-Zn2Al/PU (polyurethane) composite films have been studied in order to investigate their applicability as new photodynamic surfaces. These films comprise a PdTPPC porphyrin photosensitizer intercalated between the lamella of Zn2Al layered double hydroxide and dispersed (1 wt%) into a polyurethane matrix. The study of the photophysical behaviour shows that the Zn2Al LDH host enhances the chemical stability of the PdTPPC guest by minimizing photobleaching and quenching aggregation effects. The singlet oxygen production under irradiation of PdTPPC-Zn2Al/PU composite films is confirmed by the observation of an O2(1Δg) emission band centered at 1274 nm. Furthermore, the value of the rate constant kq for the PdTPPC phosphorescence quenching by oxygen kq = (8.2 ± 0.3) 10-2 s-1 Pa-1 indicates a slow diffusion of oxygen into and out of the PU polymer. In a second step, accelerating light ageing tests are conducted to determine the effect of singlet oxygen production on the chemical and mechanical stability of the PU matrix. Oxygen uptake experiments coupled with ATR-IR measurements indicate the probable formation of hydroxylated photoproducts but with no detrimental effects on the microstructure and the viscoelastic properties of the PU matrix as evidenced by dynamical mechanical analysis. Finally, in vitro preliminary antimicrobial tests show that PdTPPC-Zn2Al/PU composite films are able to inhibit S. aureus growth with no release of PdTPPC biocide from the PdTPPC-Zn2Al/PU composite film. We also observe a total inhibition of P. aeruginosa growth suggesting an efficacy against biofilm formation.

Toward Glycosylated Peptidic Porphyrins : a New Strategy for PDT?

Abstract New porphyrins bearing glycosyl groups and alanine moieties to improve targeting on malignant cells were synthesised in four steps. Fluorescence properties were extensively determined and indicated aggregated formation in water. These compounds produced 1 O 2 . Photocytotoxicity of these molecules against K562 Leukemia cell line was compared to the effect of hematoporphyrin.

DNA photocleavage by porphyrin-polyamine conjugates

A series of polyamine-porphyrin conjugates bearing two (cis or trans position) or four units of spermidine or spermine was synthesized. We studied the binding of these cationic porphyrins to calf thymus DNA by the means of UV-vis spectroscopy and we investigated their ability to cleave plasmid DNA in the presence of light. DNA binding and DNA photocleavage abilities were found to depend on structural characteristics as (a) the relative positions of the side chains on the porphyrin ring and (b) the nature of the attached side chains (spermidine or spermine). DNA cleavage was also studied in the presence of a singlet oxygen quencher (NaN(3)) and in the presence of a hydroxyl radical scavenger (mannitol). Singlet oxygen was the major species responsible for the cleavage of DNA previously observed. Collectively, these data show that polyamine-porphyrin conjugates could be promising phototherapeutic agents.