In this work, blends based on poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) with the incorporation of zinc phthalocyanine (ZnPc) (in concentrations of 6.35 × 10
–4
and 1.46 × ...10
–2
mol L
−1
) were fabricated using the electrospinning method. The ZnPC is known for its use as a photosensitizer in photodynamic therapy (PDT) with photophysical properties already well reported in the literature. The importance of this study is justified by the applicability of the material in the medical and disinfection field if the formation of reactive species is proven, a predominant factor in PDT. The prepared fibers were characterized by optical and scanning microscopy, differential scanning calorimetry, fluorescence, UV–Vis diffuse reflectance spectroscopy, Fourier transform-Raman spectroscopy, photoacoustic and photosensitivity test. The microscopies indicated a reduction in mean fiber diameter, with an increase in the zinc phthalocyanine concentration. The results indicate that the optical properties of the phthalocyanine remain in the solid carrier and, after intense electric field, there is the formation of reactive species. Also, through the thermal properties of the material, it was possible to notice a greater interaction of phthalocyanine with the PBAT group of the polymeric matrix.
This work presents an equation concerning effective light doses (Dabs; J cm-2) absorbed by photosensitizer molecules that are involved directly in photochemical and photodynamic processes. These ...molecules are photostimulated by different polychromatic LED sources with distinct photonic properties. The inherent photosensitizer photobleaching process, source irradiation emission spectrum (wavelength range), light source power, irradiation time, and LED-methylene blue spectral overlap degree were the relevant parameters considered for Dabs. This was performed with an experimental system comprised of methylene blue and its photosensitization ability on substrate DFBF (1,3-diphenylisobenzofuran) photodegradation, starting from different polychromatic LED sources. We demonstrated that such factors significantly affect photosensitizer light absorption, thus influencing the efficiency of a specific photochemical process. This occurs due to the selection of non-optimal experimental conditions associated with less precision from photonic source measurements, and therefore, less control on the actual Dabs. Such insights are interestingly absent in various studies with regards to a plethora of systems.
Phthalocyanine aluminum chloride (Pc) is a clinically viable photosensitizer (PS) to treat skin lesions worsened by microbial infections. However, this molecule presents a high self-aggregation ...tendency in the biological fluid, which is an in vivo direct administration obstacle. This study proposed the use of bioadhesive and thermoresponsive hydrogels comprising triblock-type Pluronic F127 and Carbopol 934P (FCarb) as drug delivery platforms of Pc (FCarbPc)-targeting topical administration. Carbopol 934P was used to increase the F127 hydrogel adhesion on the skin. Rheological analyses showed that the Pc presented a low effect on the hydrogel matrix, changing the gelation temperature from 27.2 ± 0.1 to 28.5 ± 0.9 °C once the Pc concentration increases from zero to 1 mmol L–1. The dermatological platform showed matrix erosion effects with the release of loaded Pc micelles. The permeation studies showed the excellent potential of the FCarb platform, which allowed the partition of the PS into deeper layers of the skin. The applicability of this dermatological platform in photodynamic therapy was evaluated by the generation of reactive species which was demonstrated by chemical photodynamic efficiency assays. The low effect on cell viability and proliferation in the dark was demonstrated by in vitro assays using L929 fibroblasts. The FCarbPc fostered the inhibition of Staphylococcus aureus strain, therefore demonstrating the platform’s potential in the treatment of dermatological infections of microbial nature.
Hypericin (Hyp) is considered a promising photosensitizer for Photodynamic Therapy (PDT), due to its high hydrophobicity, affinity for cell membranes, low toxicity and high photooxidation activity. ...In this study, Hyp photophysical properties and photodynamic activity against melanoma B16-F10 cells were optimized using DPPC liposomes (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) as a drug delivery system. This nanoparticle is used as a cell membrane biomimetic model and solubilizes hydrophobic drugs. Hyp oxygen singlet lifetime (τ) in DPPC was approximately two-fold larger than that in P-123 micelles (Pluronic™ surfactants), reflecting a more hydrophobic environment provided by the DPPC liposome. On the other hand, singlet oxygen quantum yield values (Φ
O
) in DPPC and P-123 were similar; Hyp molecules were preserved as monomers. The Hyp/DPPC liposome aqueous dispersion was stable during fluorescence emission and the liposome diameter remained stable for at least five days at 30 °C. However, the liposomes collapsed after the lyophilization/rehydration process, which was resolved by adding the lyoprotectant Trehalose to the liposome dispersion before lyophilization. Cell viability of the Hyp/DPPC formulation was assessed against healthy HaCat cells and high-metastatic melanoma B16-F10 cells. Hyp incorporated into the DPPC carrier presented a higher selectivity index than the Hyp sample previously solubilized in ethanol under the illumination effect. Moreover, the IC
was lower for Hyp in DPPC than for Hyp pre-solubilized in ethanol. These results indicate the potential of the formulation of Hyp/DPPC for future biomedical applications in PDT treatment.
The removal of organic pollutants from water is a significant challenge in environmental remediation. In this study, the potential of ZnO and Nb2O5 semiconductors with the impregnation of three ...percentages of reduced graphene oxide (rGO) as efficient photocatalysts for the degradation of methylene blue (MB) dye aqueous solutions was investigated in a UV mini-reactor. The heterostructures were synthesized by hydrothermal method and characterized by analytical techniques, such as XRD, XPS, ATR-FTIR, Raman, TEM, N2 physisorption, photoacoustic, photoluminescence, and pHZPC. Both rGONb2O5 and rGOZnO catalysts demonstrated considerable photocatalytic activity, resulting in the degradation of MB within a relatively short time period.
Nanocarriers have been successfully used to solubilize, deliver, and increase the bioavailability of curcumin (CUR), but slow CUR release rates hinder its use as a topical photosensitizer in ...antimicrobial photodynamic therapy. A photo-responsive polymer (PRP) was designed for the light-triggered release of CUR with an effective light activation-dependent antimicrobial response. The characterization of the PRP was compared with non-responsive micelles comprising Pluronics™ P123 and F127. According to the findings, the PRP formed photo-responsive micelles in the nanometric scale (< 100 nm) with a lower critical micelle concentration (3.74 × 10
M
, 5.8 × 10
M
, and 7.2 × 10
M
for PRP, F127, P123, respectively, at 25°C) and higher entrapment efficiency of CUR (88.7, 77.2, and 72.3% for PRP, F127, and P123 micelles, respectively) than the pluronics evaluated. The PRP provided enhanced protection of CUR compared to P123 micelles, as demonstrated in fluorescence quenching studies. The light-triggered release of CUR from PRP occurred with UV light irradiation (at 355 nm and 25 mW cm
) and a cumulative release of 88.34% of CUR within 1 h compared to 80% from pluronics after 36 h.
studies showed that CUR-loaded PRP was non-toxic to mammal cell, showed inactivation of the pathogenic microorganisms
,
, and methicillin-resistant
, and decreased biofilm biomass when associated with blue light (455 nm, 33.84 J/cm
). The findings show that the CUR-loaded PRP micelle is a viable option for antimicrobial activity.
Aluminum Chloride Phthalocyanine (AlPcCl) can be used as a photosensitizer (PS) for Photodynamic Inactivation of Microorganisms (PDI). The AlPcCl showed favorable characteristics for PDI due to high ...quantum yield of singlet oxygen (ΦΔ) and photostability. Physicochemical properties and photodynamic inactivation of AlPcCl incorporated in polymeric micelles of tri‐block copolymer (P‐123 and F‐127) against microorganisms Staphylococcus aureus, Escherichia coli and Candida albicans were investigated in this work. Previously, it was observed that the AlPcCl undergoes self‐aggregation in F‐127, while in P‐123 the PS is in a monomeric form suitable for PDI. Due to the self‐aggregation of AlPcCl in F‐127, this formulation did not show any effect on these microorganisms. On the other hand, AlPcCl formulated in P‐123 was effective against S. aureus and C. albicans and the death of microorganisms was dependent on the PS concentration and illumination time. Additionally, it was found that the values of PS concentration and illumination time to eradicate 90% of the initial population of microorganisms (IC90 and D90, respectively) were small for the AlPcCl in P‐123, showing the effectiveness of this formulation for PDI.
Formulations of aluminum chloride phthalocyanine were prepared in polymeric micelles of pluronic™ surfactants F‐127 and P‐123 and tested for inactivation of microorganisms. The process of incorporation of AlPcCl on copolymers was effective and the formulation obtained for the system AlPcCl/P‐123 had good results against different kind of microorganisms.
•Three alkali pretreated agroindustrial wastes were characterized by SEM, chemical composition, ATR-FTIR, BET, XRD and pHzpc.•Cellulose was the main component of each alkali pretreated waste, 49 to ...59 g 100 g−1.•The lignocellulosic biosorbents presented adsorption of MB higher than 90% from pH 3.0 to 11.0.•Quadratic models were obtained from Box-Behnken design with factors pH, dosage and concentration.
Lignocellulosic residues of sugarcane bagasse (SCB), corn husk (CHW) and rice husk (RHW) were evaluated as renewable and low cost bioadsorbents of the methylene blue dye. Residues were treated with a 0.10 mol L−1 NaOH solution to remove part of the polymeric component of the fibers and to intensify the dye adsorption. They were characterized by chemical composition, SEM, ATR-FTIR, BET, XRD and pHzpc. The adsorbents were evaluated using the 23 full Box-Behnken design with the variables pH, dye concentration and adsorbent dosage, obtaining descriptive mathematical models for adsorption percentage and also the response surfaces. Cellulose, hemicellulose and lignin were the main constituents of the materials analyzed, totalizing 81 to 91 g 100 g −1, whose lignocellulosic groups were verified by ATR-FTIR. The wastes presented high percentage of adsorption: 95.7 ± 1.9 % for SCB, 98.5 ± 1.2 % for CHW and 95.4 ± 0.8 % for RHW at the central point of the experimental design. Therefore, alkali treatment provided an interesting alternative to produce efficient bioadsorbents from agroindustrial wastes.
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Photodynamic therapy (PDT) is a therapeutic modality that has shown effectiveness in the inactivation of cancer cell lines and microorganisms. Treatment consists of activating the photosensitizer ...(PS) upon light irradiation of adequate wavelength. After reaching the excited state, the PS can handle the intersystem conversion through energy transfer to the molecular oxygen, generating reactive oxygen species. This especially applies to singlet oxygen (1O2), which is responsible for the selective destruction of the sick tissue. Photosensitizing compounds (chlorophylls and derivatives) existing in the spinach extract have applicability for PDT. This study aimed to develop and characterize the thermoresponsive bioadhesive system composed of Pluronic F127 20.0%- and Carbopol 934P 0.2% (w/w) (FC)-containing chlorophyll-based extract 0.5% (w/w) (FC-Chl). Mechanical and rheological properties, in vitro release, sol–gel transition temperature, and ex vivo permeability of the spinach extract PS components (through pig ear skin) were investigated. Furthermore, photodynamic activity of the system was accessed through uric acid and time-solved measurements. The sol–gel transition temperature obtained for the FC-Chl system was 28.8 ± 0.3 °C. Rheological and texture properties of the platform were suitable for use as a dermatological system, exhibiting easy application and good characteristics of retention in the place of administration. In vitro release studies showed the presence of two distinct mechanisms that reasonably obey the zero-order and first-order kinetics models. PS components presented skin permeability and reached a permeation depth of 830 μm (between the epidermis and dermis). The photodynamic evaluation of the FC-Chl system was effective in the degradation of uric acid. The quantum yield (ΦΔ 1O2) and life time (τ1O2) of singlet oxygen showed similar values for the spinach extract and the isolated chlorophyll a species in ethanol. These results allowed for the classification of the FC-Chl platform as potentially useful for the delivery of the chlorophyll-based extract in the topic PDT, suggesting that it is worthy for in vivo evaluation.
Xanthenes form to an important class of dyes which are widely used. Most of them present three acid-base groups: two phenolic sites and one carboxylic site. Therefore, the pKa determination and the ...attribution of each group to the corresponding pKa value is a very important feature. Attempts to obtain reliable pKa through the potentiometry titration and the electronic absorption spectrophotometry using the first and second orders derivative failed. Due to the close pKa values allied to strong UV-Vis spectral overlap, multivariate analysis, a powerful chemometric method, is applied in this work. The determination was performed for eosin Y, erythrosin B, and bengal rose B, and also for other synthesized derivatives such as 2-(3,6-dihydroxy-9-acridinyl) benzoic acid, 2,4,5,7-tetranitrofluorescein, eosin methyl ester, and erythrosin methyl ester in water. These last two compounds (esters) permitted to attribute the pKa of the phenolic group, which is not easily recognizable for some investigated dyes. Besides the pKa determination, the chemometry allowed for estimating the electronic spectrum of some prevalent protolytic species and the substituents effects evaluation.
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