Emerging hybrid biomaterials for oxidative stress induced photodynamic therapy

Photosensitizer-singlet oxygen sensor conjugated silica nanoparticles for photodynamic therapy and bioimaging

Intracellular singlet oxygen (1O2) generation and detection help optimize the outcome of photodynamic therapy (PDT). Theranostics programmed for on-demand phototriggered 1O2 release and bioimaging have great potential to transform PDT. We demonstrate an ultrasensitive fluorescence turn-on sensor-sensitizer-RGD peptide-silica nanoarchitecture and its 1O2 generation-releasing-storing-sensing properties at the single-particle level or in living cells. The sensor and sensitizer in the nanoarchitecture are an aminomethyl anthracene (AMA)-coumarin dyad and a porphyrin or CdSe/ZnS quantum dots (QDs), respectively. The AMA in the dyad quantitatively quenches the fluorescence of coumarin by intramolecular electron transfer, the porphyrin or QD moiety generates 1O2, and the RGD peptide facilitates intracellular delivery. The small size, below 200 nm, as verified by scanning electron microscopy and differential light scattering measurements, of the architecture within the 1O2 diffusion length enables fast and efficient intracellular fluorescence switching by the tandem ultraviolet (UV)-visible or visible-near-infrared (NIR) photo-triggering. While the red emission and 1O2 generation by the porphyrin are continually turned on, the blue emission of coumarin is uncaged into 230-fold intensity enhancement by on-demand photo-triggering. The 1O2 production and release by the nanoarchitecture enable spectro-temporally controlled cell imaging and apoptotic cell death; the latter is verified from cytotoxic data under dark and phototriggering conditions. Furthermore, the bioimaging potential of the TCPP-based nanoarchitecture is examined in vivo in B6 mice.

Promising onychomycosis treatment with hypericin-mediated photodynamic therapy: case reports

BACKGROUND

Onychomycosis (OM) is a common nail plate disorder caused by dermatophyte molds, yeasts, and non-dermatophyte molds, which use keratin in the nail plate as an energy source. OM is characterized by dyschromia, increased nail thickness, subungual hyperkeratosis, and onychodystrophy, and is typically treated with conventional antifungals despite frequent reports of toxicity, fungal resistance, and OM recurrence. Photodynamic therapy (PDT) with hypericin (Hyp) as a photosensitizer (PS) stands out as a promising therapeutic modality. When excited by a specific wavelength of light and in the presence of oxygen, to lead to photochemical and photobiological reactions on the selected targets.

METHODS

OM diagnosis was made in three suspected cases, and the causative agents were identified by classical and molecular methods, and confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Susceptibility of planktonic cells of the clinical isolates to conventional antifungals and PDT-Hyp was evaluated, and photoacoustic spectroscopy (PAS) of Hyp permeation in nail fragments ex vivo was analyzed. Furthermore, the patients opted to undergo PDT-Hyp treatment and were subsequently followed up. The protocol was approved by the human ethics committee (CAAE, number 14107419.4.0000.0104).

RESULTS

The etiological agents of OM in patients ID 01 and ID 02 belonged to the Fusarium solani species complex, being identified as Fusarium keratoplasticum (CMRP 5514) and Fusarium solani (CMRP 5515), respectively. For patient ID 03, the OM agent was identified as Trichophyton rubrum (CMRP 5516). PDT-Hyp demonstrated a fungicidal effect in vitro, with reductions of ≥3 log₁₀ (p<0.0051 and p<0.0001), and the PAS analyses indicated that Hyp could completely permeate through both healthy and OM-affected nails. After four sessions of PDT-Hyp, mycological cure was observed in all three cases, and after seventh months, clinical cure was confirmed. PDT-Hyp showed satisfactory results in terms of efficacy and safety, and thus can be considered a promising therapy for the clinical treatment of OM.

Potential of chitosan nanoparticle/fluoride nanocomposite for reducing the toxicity of fluoride an in-vivo study on the rat heart functions: Hematopoietic and immune systems

The present work-study the decreasing fluoride ions toxicity on the rat heart via loading them on the chitosan nanoparticles (Cs NPs) surface to form the biologically compatible composite (Cs@NaF). The obtained nanocomposite was characterized by different techniques such as field emission scanning electron microscopy (FEG-SEM), zeta potential, and x-ray diffraction (XRD). The biochemical parameters in the albino rats perform, where twenty-eight male adult Sprague Dawley rats (average body weight of 150 ± 10 g) were obtained from the Faculty of Agriculture, Alexandria University, then acclimatized for two weeks before the experiment and divided into four groups in galvanized wire cages at room temperature (22-25 °C) with a 12-h photoperiod and fed a well-balanced commercial diet. The blood samples were obtained from the vena cava of the rat heart via estimation of the troponin T, Lactate dehydrogenase, and creatine phosphokinase. Also, immunoglobulins (IgA, IgM, and IgG) and hematological measurements have been performed on the rat heart. To express all of the data, the mean and standard error of the mean are utilized by (ANOVA), followed by Tukey's multiple comparison test. The modified chitosan with fluoride decreases the toxicity of fluoride via improving the rat heart function due to the presence of Cs NPs helped to mitigate some of the negative effects of fluoride therapy.

NF‑κB/IκBα signaling pathways are essential for resistance to heat stress‑induced ROS production in pulmonary microvascular endothelial cells

The results of a previous study demonstrated that heat stress (HS) triggered oxidative stress, which in turn induced the apoptosis of epithelial cells. These results uncovered a novel mechanism underlying the activation of NF-κB in primary human umbilical vein endothelial cells. The present study aimed to further investigate the role of NF-κB/IκBα signaling pathways in the inhibition of HS-induced reactive oxygen species (ROS) generation and cytotoxicity in endothelial cells. The results of the present study demonstrated that HS triggered a significant amount of NF-κB and IκBα nuclear translocation without IκBα degradation in a time-dependent manner. Mutant constructs of IκBα phosphorylation sites (Ser32, Ser36) were employed in rat pulmonary microvascular endothelial cells (PMVECs). Cell Counting Kit-8 assays demonstrated that both the small interfering (si)RNA-mediated knockdown of p65 and IκBα mutant constructs significantly decreased cell viability and aggravated ROS accumulation in HS-induced rat PMVECs compared with the control. Additionally, western blot analysis revealed that p65 siRNA attenuated the protein expression of IκBα. However, IκBα mutant constructs failed to attenuate NF-κB activation and nuclear translocation, indicating that IκBα-independent pathways contributed to NF-κB activity and nucleus translocation in a time-dependent manner following HS. Collectively, the results of the present study suggested that the NF-κB/IκBα pathway was essential for resistance to HS-induced ROS production and cytotoxicity in rat PMVECs, and that it could be a potential therapeutic target to reduce the mortality and morbidity of heat stroke.