Gold-chlorophyll a-hybrid nanoparticles and chlorophyll a/cetyltrimethylammonium chloride self-assembled-suprastructures as novel carriers for chlorophyll a delivery in water medium: Photoactivity and photostability

Rizzi, Vito; Vurro, Davide; Placido, Tiziana; Fini, Paola; Petrella, Andrea; Semeraro, Paola; Cosma, Pinalysa

doi:10.1016/j.colsurfb.2017.11.009

Cited by 21 publications

(13 citation statements)

References 55 publications

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“…The previous studies have shown that chl a was effectively solubilized in the aqueous medium by means of various cyclodextrins (CDs) and indicated the formation of host-guest inclusion complexes between chl a and CDs [23,24]. More recently, chl a was blocked inside the chitosan films, and cetyltrimethylammonium chloride was chosen to solubilize it in the water medium with gold nanoparticles [25,26]. However, despite numerous research results on chl a organization and application, it should be borne in mind that, as was advised by Hans Fischer during his Nobel lecture, 'the chlorophyll molecule still presents many riddles'.…”

Section: Introductionmentioning

confidence: 99%

“…Hence, in this paper, an aqueous mixture with the non-ionic detergent Cremophor EL (CrEL) allowing the delivery of chl a molecules in the water system, mainly in the monomeric molecular form was prepared. Chl a monomerization has significant importance due to its known photoactivity [26] and expected efficient uptake of such a molecular form. A small molecule tends to penetrate the cell membrane more easily than a larger one.…”

Section: Introductionmentioning

confidence: 99%

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Cremophor EL Nano-Emulsion Monomerizes Chlorophyll a in Water Medium

et al. 2019

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In this paper, the application of a non-ionic detergent Cremophor EL for monomerization of chlorophyll a in an aqueous medium is studied. The spectrophotometric properties of chlorophyll a encapsulated into the Cremophor EL nano-emulsion system were characterized by electronic absorption, steady-state and time-resolved fluorescence as well as circular dichroism spectroscopy. The results have shown that chlorophyll a dissolves more efficiently in the aqueous medium containing low-level Cremophor (5 wt%) than at an ethanolic solution even in the concentration of 10−4 M. The molecular organization of the chlorophyll a in the Cremophor EL nano-micelles was also investigated by means of Raman spectroscopy. The spectral changes in the frequency of the C=O stretching group were used to distinguish the aggregation state of chlorophyll. It was revealed that chlorophyll a exists dominantly in the monomeric form in the Cremophor EL aqueous solution. The promising aspect of the use of Cremophor EL nano-emulsion as a delivery system is to maintain stable chlorophyll monomer in an aqueous medium. It would open the potential for a new, practical application of chlorophyll a in medicine, as a dietary supplement or studies on molecular organization of chlorophyll a in the well-defined artificial system.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cremophor EL Nano-Emulsion Monomerizes Chlorophyll a in Water Medium

et al. 2019

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“…Despite that, the array of photoproperties, biocompatibility and natural abundance of chlorophyll make it a suitable sonosensitizer candidate for SDT application [19], even if the hydrophobicity of the chlorophyll macrocycle is a limit that cuts down the applications in aqueous environment. Therefore, some chlorophyll derivatives have been obtained and associated to colloidal carriers, such as micelles, ethosomes, liposomes, and nanoparticles, but only for PDT applications [20][21][22][23][24][25]. This is the first work that investigates chlorophyll as it is in nature, such as a mixture of different chlorophyll molecules, including chlorophyll a, b and pheophytin a.…”

Section: Introductionmentioning

confidence: 99%

Exploiting Lipid and Polymer Nanocarriers to Improve the Anticancer Sonodynamic Activity of Chlorophyll

et al. 2020

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Sonodynamic therapy is an emerging approach that uses low-intensity ultrasound to activate a sonosensitizer agent triggering its cytotoxicity for selective cancer cell killing. Several molecules have been proposed as sonosensitizer agents, but most of these, as chlorophyll, are strongly hydrophobic with a low selectivity towards cancer tissues. Nanocarriers can help to deliver more efficiently the sonosensitizer agents in the target tumor site, increasing at the same time their sonodynamic effect, since nanosystems act as cavitation nuclei. Herein, we propose the incorporation of unmodified plant-extracted chlorophyll into nanocarriers with different composition and structure (i.e., liposomes, solid lipid nanoparticles and poly(lactic-co-glycolic acid) nanoparticles) to obtain aqueous formulations of this natural pigment. The nanocarriers have been deeply characterized and then incubated with human prostatic cancer cells (PC-3) and spheroids (DU-145) to assess the influence of the different formulations on the chlorophyll sonodynamic effect. The highest sonodynamic cytotoxicity was obtained with chlorophyll loaded into poly(lactic-co-glycolic acid) nanoparticles, showing promising results for future clinical investigations on sonodynamic therapy.

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“…The results have shown that the molecular organization of chl a in the CrEL nano-emulsion is monomeric [ 10 ]. This is relevant due to the high photoactivity of chl monomer [ 16 ] and the expected efficient uptake of such a small molecule but not a larger aggregated form.…”

Section: Introductionmentioning

confidence: 99%

Stability of Chlorophyll a Monomer Incorporated into Cremophor EL Nano-Micelles under Dark and Moderate Light Conditions

et al. 2020

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In this paper, stability of chlorophyll a monomers encapsulated into the Cremophor EL nano-micelles was studied under dark and moderate light conditions, typical of a room with natural or artificial lighting, in the presence of oxygen. The pigment stability against visible light was determined using the dynamic light scattering and molecular spectroscopy (UV-Vis absorption and stationary fluorescence) methods. Chlorophyll a, at the molar concentration of 10-5 M, was dissolved in the 5 wt% Cremophor emulsion for comparison in the ethanolic solution. The stability of such a self-assembly pigment–detergent nano-system is important in the light of its application on the commercial-scale. The presented results indicate the high stability of the pigment monomeric molecular organization in the nano-emulsion. During the storage in the dark, the half-lifetime was calculated as about 7 months. Additionally, based on the shape of absorption and fluorescence emission spectra, chlorophyll aggregation in the Cremophor EL aqueous solution along with the time was excluded. Moreover, the average size of detergent micelles as chlorophyll carriers was not affected after 70 days of the nano-system storage. Pigment stability against the moderate white light (0.1 mW) did not differ significantly from storage conditions in the dark. The photooxidation products, detected by occurrence of new absorption and fluorescence emission bands, was estimated on the negligible level. The stability of such a self-assembly pigment–detergent nano-system would potentially broaden the field of chlorophyll a (chl a) application in the food industry, medicine or artificial photosynthesis models.

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Gold-chlorophyll a-hybrid nanoparticles and chlorophyll a/cetyltrimethylammonium chloride self-assembled-suprastructures as novel carriers for chlorophyll a delivery in water medium: Photoactivity and photostability

Cited by 21 publications

References 55 publications

Cremophor EL Nano-Emulsion Monomerizes Chlorophyll a in Water Medium

Cremophor EL Nano-Emulsion Monomerizes Chlorophyll a in Water Medium

Exploiting Lipid and Polymer Nanocarriers to Improve the Anticancer Sonodynamic Activity of Chlorophyll

Stability of Chlorophyll a Monomer Incorporated into Cremophor EL Nano-Micelles under Dark and Moderate Light Conditions

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