Free Methylene Blue Research Articles

Enzyme-Assisted Electrochemical Point-of-Care Test for miRNA Detection in Liquid Biopsy.

In the personalized medicine era, affordable and portable devices for quicker cancer monitoring, even in remote areas, are crucial. To address this need, we have developed an enzyme-assisted electrochemical point-of-care (POC) test for application toward liquid biopsy. In particular, miR-200a-5p has been taken into account as the model target due to its correlation for triple negative breast cancer (TNBC) prognosis. The proposed platform has been conceived as signal-ON, and the detection architecture is based on the presence of a duplex-specific nuclease (DSN) that is selective for DNA-RNA heteroduplexes. When the miRNA is recognized by an ad-hoc designed DNA probe, the DSN enzyme enables for the isothermal target recycling and signal enhancement, which is essential for detecting the miRNA trace in biofluids. Introducing a methylene blue (MB) modification on the DNA probe, a single miRNA strand is capable of triggering multiple DSN cleavage circles, increasing the free MB and thus the electrochemical signal recorded. All the optimization studies have been carried out using a screen-printed strip, resulting in a dynamic range comprised between 0.1 pM and 100 nM and a detection limit down to the fM level. A satisfactory selectivity was highlighted by interrogating the system toward random miRNA target mixtures, and the platform was also tested in spiked commercial serum samples.

Polydopamine-Coated Liposomes for Methylene Blue Delivery in Anticancer Photodynamic Therapy: Effects in 2D and 3D Cellular Models.

Photodynamic therapy (PDT) is a therapeutic option for cancer, in which photosensitizer (PS) drugs, light, and molecular oxygen generate reactive oxygen species (ROS) and induce cell death. First- and second-generation PSs presented with problems that hindered their efficacy, including low solubility. Thus, second-generation PSs loaded into nanocarriers were produced to enhance their cellular uptake and therapeutic efficacy. Among other compounds investigated, the dye methylene blue (MB) showed potential as a PS, and its photodynamic activity in tumor cells was reported even in its nanocarrier-delivered form, including liposomes. Here, we prepared polydopamine (PDA)-coated liposomes and efficiently adsorbed MB onto their surface. lipoPDA@MB vesicles were first physico-chemically characterized and studies on their light stability and on the in vitro release of MB were performed. Photodynamic effects were then assessed on a panel of 2D- and 3D-cultured cancer cell lines, comparing the results with those obtained using free MB. lipoPDA@MB uptake, type of cell death induced, and ability to generate ROS were also investigated. Our results show that lipoPDA@MB possesses higher photodynamic potency compared to MB in both 2D and 3D cell models, probably thanks to its higher uptake, ROS production, and apoptotic cell death induction. Therefore, lipoPDA@MB appears as an efficient drug delivery system for MB-based PDT.

Artículo traducido] Tratamientos tópicos e intralesionales en hidradenitis supurativa. Una revisión sistemática de la literatura

Background and objectiveTopical and intralesional (IL) treatments may be considered the first-line therapy in patients with hidradenitis suppurativa (HS); however, the evidence supporting their use is limited. The aim of our review is to evaluate the efficacy and safety profile of topical and IL treatments in patients with HS. Materials and methodsWe designed a systematic review of the current medical literature available following the PICO(T) method. And including all types of studies (Study type [T]) of individuals with HS of any sex, age, and ethnicity (Population [P]) who received any topical or IL treatment for HS (Intervention [I]) compared to placebo, other treatments, or no treatment at all (Comparator [C]), and reported efficacy and/or safety outcomes (Outcomes [O]). Two outcomes were defined: quality of life and the no. of patients with, at least, one adverse event. The search was conducted in the Cochrane Library, MEDLINE, and Embase databases; study selection was performed based on pre-defined criteria. The risk of bias was determined in each study. ResultsWe obtained a total of 11,363 references, 31 of which met the inclusion criteria. These studies included 1143 patients with HS, 62% of whom were women. A total of 10, 8, 6, 2, and 5 studies, respectively, evaluated the use of photodynamic therapy (PDT), glucocorticoids, resorcinol, topical antibiotics, and other interventions. Most articles were case series (n=25), with only five randomized clinical trials (RCTs) and one cohort study. RCTs showed improvement in disease activity with topical clindamycin and botulinum toxin (BTX) vs placebo, and PDT with methylene blue (MB) niosomal vs free MB; however, intralesional triamcinolone acetonide was not superior to placebo. The risk of bias was low in three RCTs and high in two RCTs. ConclusionThe quality of evidence supporting the use of topical, or IL treatments is low. However, it supports the use of topical clindamycin, PDT, and BTX. Well-designed RCTs with standardized outcomes and homogeneous populations of patients and lesions are needed to support decision-making in the routine clinical practice.

Topical and Intralesional Therapies for Hidradenitis Suppurativa: A Systematic Literature Review

Background and objectiveTopical and intralesional (IL) treatments may be considered the first-line therapy in patients with hidradenitis suppurativa (HS); however, the evidence supporting their use is limited. The aim of our review is to evaluate the efficacy and safety profile of topical and IL treatments in patients with HS. Materials and methodsWe designed a systematic review of the current medical literature available following the PICO(T) method. And including all types of studies (Study type [T]) of individuals with HS of any sex, age, and ethnicity (Population [P]) who received any topical or IL treatment for HS (Intervention [I]) compared to placebo, other treatments, or no treatment at all (Comparator [C]), and reported efficacy and/or safety outcomes (Outcomes [O]). Two outcomes were defined: quality of life and the no. of patients with, at least, one adverse event. The search was conducted in the Cochrane Library, MEDLINE, and EMBASE databases; study selection was performed based on pre-defined criteria. The risk of bias was determined in each study. ResultsWe obtained a total of 11,363 references, 31 of which met the inclusion criteria. These studies included 1143 patients with HS, 62% of whom were women. A total of 10, 8, 6, 2, and 5 studies, respectively, evaluated the use of photodynamic therapy (PDT), glucocorticoids, resorcinol, topical antibiotics, and other interventions. Most articles were case series (n=25), with only five randomized clinical trials (RCTs) and one cohort study. RCTs showed improvement in disease activity with topical clindamycin and botulinum toxin (BTX) vs placebo, and PDT with methylene blue (MB) niosomal vs free MB; however, intralesional triamcinolone acetonide was not superior to placebo. The risk of bias was low in three RCTs and high in two RCTs. ConclusionThe quality of evidence supporting the use of topical, or IL treatments is low. However, it supports the use of topical clindamycin, PDT, and BTX. Well-designed RCTs with standardized outcomes and homogeneous populations of patients and lesions are needed to support decision-making in the routine clinical practice.

Controllable self-assembled DNA nanomachine enable homogeneous rapid electrochemical one-pot assay of lung cancer circulating tumor cells

A homogeneous rapid (45 min) one-pot electrochemical (EC) aptasensor was established to quantitatively detect circulating tumor cells (CTCs) in lung cancer patients using mucin 1 as a marker. The core of this study is that the three single-stranded DNA (Y1, Y2, and Y3) could be hybridized to form Y-shaped DNA (Y-DNA) and further self-assemble to form DNA nanosphere. The aptamer of mucin 1 could be complementary and paired with Y1, thus disrupting the conformation of the DNA nanosphere. When mucin 1 was present, the aptamer combined specifically with mucin 1, thus preserving the DNA nanosphere structure. Methylene blue (MB) acted as a signal reporter, which could be embedded between two base pairs in the DNA nanosphere to form a DNA nanosphere-MB complex, reducing free MB and resulting in a lower electrochemical signal. The results demonstrated that the linear ranges for mucin 1 and A549 cells were 1 ag/mL-1 fg/mL and 1–100 cells/mL, respectively, with minimum detectable concentrations were 1 ag/mL and 1 cell/mL, respectively. The quantitative analysis of CTCs in 44 clinical blood samples was performed, and the results were consistent with the computerized tomography (CT) images, pathological findings and folate receptor-polymerase chain reaction (FR-PCR) kits. The receiver operating characteristic (ROC) curve exhibited an area under the curve (AUC) value of 0.970. The assay revealed 100% specificity and 94.1% sensitivity. It is believed that this electrochemical aptasensor could provide a new approach to detect CTCs.

Pd(II)-based coordination polymer nanosheets for ratiometric colorimetric and photothermal dual-mode assay of serum alkaline phosphatase

Fabrication of a multi-signal readout assay with high sensitivity and selectivity is highly desirable for clinical and biochemical analysis, but remains a challenge due to laborious procedures, large-scale instruments, and inadequate accuracy. Herein, a straightforward, rapid, and portable detection platform based on palladium(II) methylene blue (MB) coordination polymer nanosheets (PdMBCP NSs) was unveiled for the ratiometric dual-mode detection of alkaline phosphatase (ALP) with temperature and colorimetric signal readout properties. The sensing mechanism is the ALP-catalyzed generation of ascorbic acid for competitive binding and etching PdMBCP NSs to release free MB in a quantitive means for detection. Specifically, ALP addition led to the decrease of temperature signal readout from the decomposed PdMBCP NSs under 808 nm laser excitation, and simultaneous increase of the temperature from the generated MB with a 660 nm laser, together with the corresponding absorbance changes at both wavelengths. Notably, this ratiometric nanosensor exhibited a detection limit of 0.013 U/L (colorimetric) and 0.095 U/L (photothermal) within 10 min, respectively. The reliability and satisfactory sensing performance of the developed method were further confirmed by clinic serum samples. Therefore, this study provides a new insight for the development of dual-signal sensing platforms for convenient, universal, and accurate detection of ALP.

Aspects of the interaction of pectin-coated Ag nanoparticles with methylene blue with regard to photodynamic applications

The promising future of photodynamic therapy has led to progress in the design of highly effective new-generation photosensitizers based on the combination of plasmonic metal nanoparticles and fluorescent molecules to kill cancer cells and bacteria. In this work, the details of the interaction of pectin-coated Ag nanocomposites (NCs) of different sizes (8, 10, 13, and 28 nm) and various types of pectin shells with the classical photosensitizer methylene blue (MB) were investigated. Pectin-Ag NCs were characterized by UV–vis spectroscopy, DLS, TEM, and XPS. The enhanced singlet oxygen generation effect of pectin-Ag@MB complexes was size-dependent (the smaller the size of the plasmonic particles, the higher the 1O2 generation) and associated with the local concentration of the dye in different molecular forms in the pectin shell of nanoparticles. In cell experiments, the pectin-Ag@MB complexes did not show enhanced phototoxicity or cellular uptake towards cancer cells, compared to free MB. The prolonged release of MB from the complex in a phosphate-buffered saline solution (pH 7.4) was observed. The amount of irreversibly bound MB depended on the type of pectin shell and equaled 1.13, 1.45, and 2.57 µg per mg pectin for Citrus25-Ag, Classic25-Ag, and Classic10-Ag NCs, respectively. The obtained physicochemical insights supplement the present understanding of the fundamental aspects of the interaction between plasmonic polymer-capped nanoparticles and MB and could be important for the rational design of new theranostic agents.

Urea-Bond Scission Induced by Therapeutic Ultrasound for Biofunctional Molecule Release.

Ultrasound-triggered remote control of biomolecular functions in cells provides unique advantages for us to interrogate nature. However, strategies to design therapeutic ultrasound-responsive functional molecules remain elusive, and rare ultrasound-cleavable chemical bonds have been developed to date. Herein, therapeutic ultrasound (1 MHz)-induced scission of urea bonds for drug release is demonstrated for the first time. Such a transformation has been verified to be initiated by hydroxyl radicals generated in the interior of cavitation bubbles, occurring specifically at the cavitation bubble-liquid interface. A series of urea-bond-containing prodrugs based on methylene blue (MB), namely MBUs, are designed. Upon sonication with low-intensity therapeutic ultrasound, the urea bonds linked with primary amines can be selectively cleaved, and free MB is released in a physiologically relevant environment, accompanied by recovered absorbance, fluorescence, and photosensitivity. Moreover, an FDA-approved alkylating agent (i.e., melphalan) bearing urea bond is also developed (MBU-Mel), successfully achieving ultrasound-triggered drug release in deep-seated cancer cells (mimic with 1 cm pigskin), showing the scalability of our ultrasound-responsive molecule platform in bioactive molecules release. This may set the starting point for therapeutic ultrasound-induced drug release, making a forward step in "sonopharmacology".

In vitro photodynamic therapy of methylene blue-loaded acetyl resistant starch nanoparticles

BackgroundCombination therapies comprising multiple methods, such as photodynamic therapy have been applied to be complements chemotherapy as they increase the therapeutic efficiency by enabling the intelligent drug delivery to target sites by exposing the photosensitizer to light and activating it in the tumor tissue. This study evaluated in vitro photodynamic therapy of methylene blue (MB)-loaded acetyl resistant starch (ARS) nanoparticles (NPs).MethodsARS was synthesized by the reaction between resistant starch (RS) and acetic anhydride. MB-loaded ARS NPs and ARS NPs were prepared by a single emulsion method. Synthesized ARS was measured by NMR. Prepared ARS NPs and MB-loaded ARS NPs were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction, UV/Vis, and circular dichroism (CD). MB-loaded ARS NPs were treated in mouse colon cancer cells (CT-26) and they were treated under near-infrared (NIR) laser irradiation.ResultsSynthesis of ARS was confirmed by NMR and the degree of substitutions in the ARS was 7.1. The morphologies of ARS NPs observed by TEM were spherical shapes and the particle sizes of ARS NPs were 173.4 nm with a surface charge of − 17.24 mV. The d-spacing of ARS NPs was smaller than those of RS and the conformational changes of RS occurred by the formation of self-assembled polymeric NPs with induction of CD of the MB by chiral ARS NPs. The phototoxicity of CT-26 cells treated by MB-loaded ARS NPs dramatically decreased in a dose-dependent manner under NIR laser irradiation compared to free MB.ConclusionThis study demonstrated the ordered nanosized structures in the ARS NPs and conformational change from random coil structure of RS to alpha-helices one of ARS occurred and CD of the achiral MB was induced. The MB-loaded ARS NPs showed a higher generation of reactive oxygen species (ROS) in the CT-26 cells than free MB with the NIR laser irradiation and resulting in phototoxicity under irradiation.

Vehicle-Free Nanotheranostic Self-Assembled from Clinically Approved Dyes for Cancer Fluorescence Imaging and Photothermal/Photodynamic Combinational Therapy.

Phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT) has attracted growing attention as a noninvasive option for cancer treatment. At present, researchers have developed various “all-in-one” nanoplatforms for cancer imaging and PTT/PDT combinational therapy. However, the complex structure, tedious preparation procedures, overuse of extra carriers and severe side effects hinder their biomedical applications. In this work, we reported a nanoplatform (designated as ICG-MB) self-assembly from two different FDA-approved dyes of indocyanine green (ICG) and methylene blue (MB) without any additional excipients for cancer fluorescence imaging and combinational PTT/PDT. ICG-MB was found to exhibit good dispersion in the aqueous phase and improve the photostability and cellular uptake of free ICG and MB, thus exhibiting enhanced photothermal conversion and singlet oxygen (1O2) generation abilities to robustly ablate cancer cells under 808 nm and 670 nm laser irradiation. After intravenous injection, ICG-MB effectively accumulated at tumor sites with a near-infrared (NIR) fluorescence signal, which helped to delineate the targeted area for NIR laser-triggered phototoxicity. As a consequence, ICG-MB displayed a combinational PTT/PDT effect to potently inhibit tumor growth without causing any system toxicities in vivo. In conclusion, this minimalist, effective and biocompatible nanotheranostic would provide a promising candidate for cancer phototherapy based on current available dyes in clinic.

An Activatable NIR Probe for the Detection and Elimination of Senescent Cells.

Cellular senescence is involved in diverse physiological processes. Accumulation of senescent cells can lead to numerous age-related diseases. Therefore, it is of great significance to develop chemical tools to effectively detect and eliminate senescent cells. Till date, a dual functional probe that could detect and eliminate senescent cells has yet been accomplished. Herein, a β-gal-activated probe, MB-βgal, based on the methylene blue (MB) fluorophore, was designed to detect and eliminate senescent cells. In the absence of β-gal, the probe showed no fluorescence and its 1O2 production efficiency was suppressed simultaneously. On the other hand, MB-βgal could be specifically activated by the high level of β-gal in senescent cells, thus, releasing free MB with near-infrared (NIR) fluorescence and high 1O2 production efficiency under light irradiation. MB-βgal demonstrated a fast response, high sensitivity, and high selectivity in detecting β-gal in an aqueous solution and was further applied to visualization and ablation of senescent cells. As a proof of concept, the dual functions of MB-βgal were successfully demonstrated in senescent HeLa cells and mouse embryonic fibroblast cells.

Surfactin-methylene blue complex under LED illumination for antibacterial photodynamic therapy: Enhanced methylene blue transcellular accumulation assisted by surfactin

Recently, increased attention has been focused on antibacterial photodynamic therapy (APDT) to treat multidrug-resistant bacterial infection due to the antibiotic abuse. Methylene blue has been used as a kind of efficient and cheap commercial photosensitizer in APDT. However, due to high hydrophilicity, methylene blue is not able to be transcellular intaken and accumulated efficiently. To promote accumulation and APDT efficiency of methylene blue, lipopeptide surfactin-methylene blue complex has been prepared through electrostatic interaction. The complex under LED irradiation was found to effectively reduce 5.0 Log10 CFU and 7.6 Log10 CFU for P. aeruginosa and S. aureus, respectively. The bacterial reduction efficiency is slightly higher than free methylene blue. The photosensitizers accumulation and APDT targeting protein have been characterized by fluorescence spectroscopy, fluorescence microscopy and protein electrophoresis techniques. These results demonstrated that more surfactin-methylene blue complex could be accumulated more into the cell, and inactivate bacteria through destroying intracellular protein under LED illumination. In comparison, free methylene blue under light could inactivate bacteria through destroying membrane protein and lipid structures. These results would provide valuable insight for developing advanced clinical medicine and designing photo-drug for photodynamic therapy.

Ligand-targeted Theranostic Liposomes combining methylene blue attached upconversion nanoparticles for NIR activated bioimaging and photodynamic therapy against HER-2 positive breast cancer

Methylene Blue (MB) based Photodynamic therapy (PDT) has gained much interest recently due to its FDA approval for treating various diseased conditions in human. Herein, we report for the first time the systematic evaluation of NIR-controlled PDT efficiency of free MB and MB attached on NaYF4:Yb, Er nanoparticles (UCNPs) i.e., MB@UCNPs encapsulated within Liposomes (LPs). The UCNPs act as an upconverting energy source for the photosensitizers dye MB for enhanced ROS generation and utilizing the remnant energy for selective tracking or bioimaging. The specificity of our nano LPs system was achieved by conjugating our newly discovered anti-HER2 peptides by phage display technique and demonstrated its specificity by confocal imaging of HER-2 overexpressing in vitro model. A significant decline in the cell viability by 83% and 64% was achieved by the LPs containing MB@UCNPs and free MB with UCNPs, respectively after 975 nm NIR laser exposure (0.60 W/cm−2) for 5 min continuous exposure. Also, the flowcytometry assay confirmed that enhanced ROS generation capability of LPs with MB@UCNPs was higher than the free MB with UCNPs, which states the relevance of the minimal distance between MB and UCNPs for higher anti-cancer efficiency.

The construction of supramolecular and hybrid Ag-AgCl nanoparticles with photodynamic therapy action on the base of tetraundecylсalix[4]resorcinarene-mPEG conjugate

The development of new nanomaterials with therapeutic potential is a modern task due to their outstanding properties and promising effectiveness. Here the usage of acylhydrazone bond-based сalix[4]resorcinarene-mPEG conjugate (C11-mPEG) in the formation of both supramolecular and hybrid nanoparticles with in vitro photodynamic therapy (PDT) activity is described. C11-mPEG is hydrolyzed with a decrease in pH of solution; the conjugate and its degradation product have the low hemolytic activity and low cytotoxicity against normal cells. The self-association of the conjugate was studied in the aqueous solutions with pH 7.4 and 5. C11-mPEG forms self-associates that serve as pH-sensitive supramolecular nanocontainers for photosensitizer Methylene Blue (MB). In the in vitro PDT experiment the stronger decrease of tumor cells (M-Hela cells) viability in the presence of encapsulated MB is observed in comparison with free MB. Also C11-mPEG acts as a stabilizing agent for Ag@AgCl nanoparticles, which were obtained with 5/1 and 2/1 Ag+/C11-mPEG molar ratio and different reducing agents (sodium borohydride and hydrazine hydrate). The stronger cytotoxicity of hybrid NPs against tumor cells in comparison with normal was shown. Further it was found that the irradiation of the hybrid nanoparticles at 630 nm leads to the sharp increase in their cytotoxicity against M-Hela cells. The high level of ROS formation in the cells in the presence of both supramolecular and hybrid NPs under in vitro PDT experiment was determined.

Controlled aggregation of methylene blue in silica–methylene blue nanocomposite for enhanced 1O2 generation

Organic photosensitizers can facilitate photochemical singlet-oxygen (1O2) production, providing a promising strategy for photocatalysis, photodynamic therapy, and environmental protection. Unfortunately, most organic photosensitizers tend to self-aggregate because of their hydrophobicity and conjugated π–π electronic structure, leading to the inactivation of their photosensitizing capabilities. Thus, the controlled aggregation of organic photosensitizers is critical for photosensitizer’s applications. We report a nanocomposite of porous silica nanoaggregates and the organic photosensitizer methylene blue (P-SiOx NAs/MB) that allows the aggregation control of methylene blue (MB). This nanocomposite-photosensitizer consists of highly dispersed MB in P-SiOx NAs and enhances 1O2 production under light irradiation without the inactivation of the photosensitizing ability of MB. The enhanced 1O2 generation rate of P-SiOx NAs/MB is 1.36 times larger than that of free MB. This behavior is contrasted with the inactivation of the photosensitizing ability of MB-encapsulated organo-silica nanoparticles, due to MB self-aggregation within the particles. This study provides a strategy for creating an efficient photosensitizer via suppression of MB self-aggregation to enhance the generation of 1O2.

Monitoring of methylene blue monomers and dimers to control the bacterialogical water quality including application to photocatalysis.

In this study, we propose the development of a rapid and reliable method to control and to monitor microbial water quality. The methylene blue (MB) decolorization assay was based on the analysis of spectral profiles of dye in interaction with a different bacterial concentration. The determination of dye decolorization rate (DDR) shows a correlation between the MB reduction rate and the bacterial density. Moreover, the kinetic of the monomer and dimer equilibrium of MB in water mainly, the monitoring of bounded MB species in relationship with a knowed concentration of target bacteria, was allowed to establish a relationship between MB decolorization rate and bacterial density. Furthermore, this method was applied to evaluate the water quality after photocatalysis. Based on this method, the photocatalytic effects on bacterial density was highlighted by the decrease in DDR after photocatalytic treatment with fractioned times (0 to 5 h); this increase was followed by a decrease of bounded MB species and, an increase in free MB forms miming the reduction of bacterial density due to the biocide effects of photocatalysis process. However, the analysis of spectra profiles shows a weak but a continuous decrease in bounded MB dimer and monomer forms in the treated water samples exempt of culturable bacteria. Moreover, the MB spectra profiles were tended toward a negative control spectrum without superposition. Thus, the possibility of the presence of viable but non-culturable bacteria was expected; therefore, to optimize this tertiary water treatment process, an extending on proceeding time was recommended to avoid the bacterial resuscitation after photocatalysis.

Photosensitizer-Trapped Gold Nanocluster for Dual Light-Responsive Phototherapy.

Photoresponsive nanomaterials have recently received great attention in the field of cancer therapy. Here, we report a photosensitizer-trapped gold nanocluster that can facilitate dual light-responsive cancer therapy. We utilized methylene blue (MB) as a model photosensitizer, gold nanocluster as a model photothermal agent, and a polymerized DNA as the backbone of the nanocluster. We synthesized MB-intercalated gold DNA nanocluster (GMDN) via reduction and clustering of gold ions on a template consisting of MB-intercalated long DNA. Upon GMDN treatment, cancer cells revealed clear cellular uptake of MB and gold clusters; following dual light irradiation (660 nm/808 nm), the cells showed reactive oxygen species generation and increased temperature. Significantly higher cancer cell death was observed in cells treated with GMDN and dual irradiation compared with non-irradiated or single light-irradiated cells. Mice systemically injected with GMDN showed enhanced tumor accumulation compared to that of free MB and exhibited increased temperature upon near infrared irradiation of the tumor site. Tumor growth was almost completely inhibited in GMDN-treated tumor-bearing mice after dual light irradiation, and the survival rate of this group was 100% over more than 60 days. These findings suggest that GMDN could potentially function as an effective phototherapeutic for the treatment of cancer disease.

Hydroxyapatite nanocomposite as a potential agent in osteosarcoma PDT.

Using Nanoplatforms as a hauler for photosensitizers is a bespoke paradigm to improve its bioavailability and to boost the PDT efficacy. Herein, the photodynamic cytotoxicity of methylene blue (MB) loaded on hydroxyapatite nanoparticles (HA-NPs) was tested against human osteosarcoma-derived cells (Saos-2 cell line). HA-NPs and HA-NPs loaded with MB (HA-NPs-MB) were prepared by a chemical precipitation method and characterized by TEM, Zeta potential, FTIR, and XRD. TEM images revealed that HA-NPs have a rod shape with a diameter of 14-17 nm and length around 46-64 nm. FTIR and Zeta potential confirmed the adsorption of cationic MB on HA-NPs. XRD pattern was identical to the standard XRD pattern of HA-NPs. Incubation of Saos-2 cells (24 h) with HA-NPs-MB then irradiation of cells (5 min) with a diode laser (808 nm), causes a higher decrement of cell viability (determined by MTT assay) than that caused by free MB. The LC50 was 57.53 µg/mL and 86.99 µg/mL for HA-NPs-MB and free MB, respectively. Thus, the nanoformulation of MB greatly reduced the dose of MB required for effective PDT. This study also investigated the mode of cell death after incubation of cells with free MB or HA-NPs-MB composite then exposure to laser radiation. The results revealed that the majority of cells died by apoptosis while a minor fraction of cells died by necrosis, especially in the case of HA-NPs-MB. Levels of caspase-3 and death receptor-4 (DR-4) were more elevated in the case of HA-NPs-MB than free MB. The effect of the prepared nanocomposite and free MB on Raw murine macrophage (RAW 264.7) viability was also examined using the MTT assay. The results indicated that HA-NPs-MB in the presence of laser has a great cytotoxic effect on macrophage cells compared to other treatments. This may present an advantage through decreasing macrophage that promotes tumor growth. In conclusion, HA-NPs-MB nanocomposite surmounts free MB and HA-NPs in destroying macrophage cells and Saos-2 cells through apoptosis in the presence of laser irradiation. This study introduces a thorough and new insight on osteosarcoma (cancer cell line Saos-2) PDT using HA-NPs-MB exploiting the biosafety of HA-NPs.

Nanovesicular Photodynamic Clinical Treatment of Resistant Plantar Warts.

Photodynamic therapy which involves the use of photosensitizer molecule activated by a light source was proven very promising for the treatment of dermatological diseases, especially the resistant ones such as recalcitrant Plantar Warts (PW). However, its efficacy is hindered by the poor permeation of the photosensitizer molecule required to initiate skin photo-induced effects. In this manuscript, the efficiency of the nano-vesicular system (transfersomes) as a potential topical drug delivery system for the photosensitizer methylene blue (MB) was investigated following clinical Photodynamic Therapy (PDT) in patients suffering from PW. Results revealed that MB transfersomal gel displayed a higher complete healing percentage for the lesions compared to the free MB gel (86.67% versus 53.57%) achieved at a lower number of treatment sessions (2.2 versus 4.14). Patients reported no signs of pain or inflammation, with no recurrence of the lesions during the follow up period of 8 months. PDT using transfersomal MB is an effective and safe therapeutic modality for the treatment of PW.

Biogenic Silver Nanoparticles Decorated with Methylene Blue Potentiated the Photodynamic Inactivation of Pseudomonas aeruginosa and Staphylococcus aureus.

The persistence of multidrug resistance among microorganisms has directed a mandate towards a hunt for the development of alternative therapeutic modalities. In this context, antimicrobial photodynamic therapy (aPDT) is sprouted as a novel strategy to mitigate biofilms and planktonic cells of pathogens. Nanoparticles (NPs) are reported with unique intrinsic and antimicrobial properties. Therefore, silver NPs (AgNPs) were investigated in this study to determine their ability to potentiate the aPDT of photosensitizer against Staphylococcus aureus and Pseudomonas aeruginosa. Biologically synthesized AgNPs were surface coated with methylene blue (MB) and studied for their aPDT against planktonic cells and biofilms of bacteria. The nano-conjugates (MB-AgNPs) were characterized for their size, shape and coated materials. MB-AgNPs showed significant phototoxicity against both forms of test bacteria and no toxicity was observed in the dark. Moreover, activity of MB-AgNPs was comparatively higher than that of the free MB, which concludes that MB-AgNPs could be an excellent alternative to combat antibiotic resistant bacteria.