In Ovo Testing Method for Inhalants on a Chorio-Allantoic Membrane

Enhanced photodynamic therapy of curcumin using biodegradable PLGA coated mesoporous silica nanoparticles

Since the available treatments are not highly effective to combat cancer, therefore, the alternative strategies are unavoidable. Photodynamic therapy (PDT) is one of the emerging approaches which is target specific and minimally invasive. This study explores the successful development of Poly (D,L-lactide-co-glycolide) (PLGA) coated mesoporous silica nanoparticles (MSNs) and their augmented effects achieved by integrating curcumin (Cur) and cetyltrimethylammonium bromide (CTAB) in the polymeric layer and silica's pores, respectively. The synthesized nanocarriers (Cur-PLGA-cMSNs) have shown preferential targeting to the cellular organelles facilitated by CTAB's and Cur's affinity to mitochondria. CTAB and Cur-based PDT induced oxidative stress and generation of reactive oxygen species (ROS), resulting in dysfunctional mitochondria and triggered apoptotic pathways. PLGA coating has produced multifunctional effects, including; gatekeeping effects at pore openings, providing an extra loading site, enhancing the hemocompatibility of MSNs, and masking the free cur-related prolonged coagulation time. Cur-PLGA-cMSNs, as a multifaceted and combative approach with synergistic effects demonstrate promising potential to enhance outcomes in cancer treatment.

Evaluating the photodynamic efficacy of nebulized curcumin-loaded liposomes prepared by thin-film hydration and dual centrifugation: In vitro and in ovo studies

Lung cancer, one of the most common causes of high mortality worldwide, still lacks appropriate and convenient treatment options. Photodynamic therapy (PDT) has shown promising results against cancer, especially in recent years. However, pulmonary drug delivery of the predominantly hydrophobic photosensitizers still represents a significant obstacle. Nebulizing DPPC/Cholesterol liposomes loaded with the photosensitizer curcumin via a vibrating mesh nebulizer might overcome current restrictions. In this study, the liposomes were prepared by conventional thin-film hydration and two other methods based on dual centrifugation. The liposomes' physicochemical properties were determined before and after nebulization, showing that liposomes do not undergo any changes. However, morphological characterization of the differently prepared liposomes revealed structural differences between the methods in terms of lamellarity. Internalization of curcumin in lung adenocarcinoma (A549) cells was visualized and quantified. The generation of reactive oxygen species because of the photoreaction was also proven. The photodynamic efficacy of the liposomal formulations was tested against A549 cells. They revealed different phototoxic responses at different radiant exposures. Furthermore, the photodynamic efficacy was investigated after nebulizing curcumin-loaded liposomes onto xenografted tumors on the CAM, followed by irradiation, and evaluated using positron emission tomography/computed tomography and histological analysis. A decrease in tumor metabolism could be observed. Based on the efficacy of curcumin-loaded liposomes in 2D and 3D models, liposomes, especially with prior film formation, can be considered a promising approach for PDT against lung cancer.

In vitro and in ovo photodynamic efficacy of nebulized curcumin-loaded tetraether lipid liposomes prepared by DC as stable drug delivery system

Lung cancer is one of the most common causes of high mortality worldwide. Current treatment strategies, e.g., surgery, radiotherapy, chemotherapy, and immunotherapy, insufficiently affect the overall outcome. In this study, we used curcumin as a natural photosensitizer in photodynamic therapy and encapsulated it in liposomes consisting of stabilizing tetraether lipids aiming for a pulmonary drug delivery system against lung cancer. The liposomes with either hydrolyzed glycerol-dialkyl-glycerol tetraether (hGDGT) in different ratios or hydrolyzed glycerol-dialkyl-nonitol tetraether (hGDNT) were prepared by dual centrifugation (DC), an innovative method for liposome preparation. The liposomes' physicochemical characteristics before and after nebulization and other nebulization characteristics confirmed their suitability. Morphological characterization using atomic force and transmission electron microscopy showed proper vesicular structures indicative of liposomes. Qualitative and quantitative uptake of the curcumin-loaded liposomes in lung adenocarcinoma (A549) cells was visualized and proven. Phototoxic effects of the liposomes were detected on A549 cells, showing decreased cell viability. The generation of reactive oxygen species required for PDT and disruption of mitochondrial membrane potential were confirmed. Moreover, the chorioallantoic membrane (CAM) model was used to further evaluate biocompatibility and photodynamic efficacy in a 3D cell culture context. Photodynamic efficacy was assessed by PET/CT after nebulization of the liposomes onto the xenografted tumors on the CAM with subsequent irradiation. The physicochemical properties and the efficacy of tetraether lipid liposomes encapsulating curcumin, especially liposomes containing hGDNT, in 2D and 3D cell cultures seem promising for future PDT usage against lung cancer.

Modern Photodynamic Glioblastoma Therapy Using Curcumin- or Parietin-Loaded Lipid Nanoparticles in a CAM Model Study

Natural photosensitizers, such as curcumin or parietin, play a vital role in photodynamic therapy (PDT), causing a light-mediated reaction that kills cancer cells. PDT is a promising treatment option for glioblastoma, especially when combined with nanoscale drug delivery systems. The curcumin- or parietin-loaded lipid nanoparticles were prepared via dual asymmetric centrifugation and subsequently characterized through physicochemical analyses including dynamic light scattering, laser Doppler velocimetry, and atomic force microscopy. The combination of PDT and lipid nanoparticles has been evaluated in vitro regarding uptake, safety, and efficacy. The extensive and well-vascularized chorioallantois membrane (CAM) of fertilized hen's eggs offers an optimal platform for three-dimensional cell culture, which has been used in this study to evaluate the photodynamic efficacy of lipid nanoparticles against glioblastoma cells. In contrast to other animal models, the CAM model lacks a mature immune system in an early stage, facilitating the growth of xenografts without rejection. Treatment of xenografted U87 glioblastoma cells on CAM was performed to assess the effects on tumor viability, growth, and angiogenesis. The xenografts and the surrounding blood vessels were targeted through topical application, and the effects of photodynamic therapy have been confirmed microscopically and via positron emission tomography and X-ray computed tomography. Finally, the excised xenografts embedded in the CAM were analyzed histologically by hematoxylin and eosin and KI67 staining.

Photoactive Parietin-loaded nanocarriers as an efficient therapeutic platform against triple-negative breast cancer

The application of photodynamic therapy has become more and more important in combating cancer. However, the high lipophilic nature of most photosensitizers limits their parenteral administration and leads to aggregation in the biological environment. To resolve this problem and deliver a photoactive form, the natural photosensitizer parietin (PTN) was encapsulated in poly(lactic-co-glycolic acid) nanoparticles (PTN NPs) by emulsification diffusion method. PTN NPs displayed a size of 193.70 nm and 157.31 nm, characterized by dynamic light scattering and atomic force microscopy, respectively. As the photoactivity of parietin is essential for therapy, the quantum yield of PTN NPs and the in vitro release were assessed. The antiproliferative activity, the intracellular generation of reactive oxygen species, mitochondrial potential depolarization, and lysosomal membrane permeabilization were evaluated in triple-negative breast cancer cells (MDA-MB-231 cells). At the same time, confocal laser scanning microscopy (CLSM) and flow cytometry were used to investigate the cellular uptake profile. In addition, the chorioallantoic membrane (CAM) was employed to evaluate the antiangiogenic effect microscopically. The spherical monomodal PTN NPs show a quantum yield of 0.4. The biological assessment on MDA-MB-231 cells revealed that free PTN and PTN NPs inhibited cell proliferation with IC50 of 0.95 µM and 1.9 µM at 6 J/cm2, respectively, and this can be attributed to the intracellular uptake profile as proved by flow cytometry. Eventually, the CAM study illustrated that PTN NPs could reduce the number of angiogenic blood vessels and disrupt the vitality of xenografted tumors. In conclusion, PTN NPs are a promising anticancer strategy in vitro and might be a tool for fighting cancer in vivo.

Highly Stable Liposomes Based on Tetraether Lipids as a Promising and Versatile Drug Delivery System

Conventional liposomes often lack stability, limiting their applicability and usage apart from intravenous routes. Nevertheless, their advantages in drug encapsulation and physicochemical properties might be helpful in oral and pulmonary drug delivery. This study investigated the feasibility and stability of liposomes containing tetraether lipids (TEL) from Thermoplasma acidophilum. Liposomes composed of different molar ratios of TEL:Phospholipon 100H (Ph) were produced and exposed to various temperature and pH conditions. The effects on size, polydispersity index, and zeta potential were examined by dynamic and electrophoretic light scattering. Autoclaving, which was considered an additional process step after fabrication, could minimize contamination and prolong shelf life, and the stability after autoclaving was tested. Moreover, 5(6)-carboxyfluorescein leakage was measured after incubation in the presence of fetal calf serum (FCS) and lung surfactant (Alveofact). The incorporation of TEL into the liposomes significantly impacted the stability against low pH, higher temperatures, and even sterilization by autoclaving. The stability of liposomes containing TEL was confirmed by atomic force microscopy as images revealed similar sizes and morphology before and after incubation with FCS. It could be concluded that increasing the molar ratio in the TEL:Ph liposome formulations improved the structural stability against high temperature, low pH, sterilization via autoclaving, and the presence of FCS and lung surfactant.

Performance of nanoparticles for biomedical applications: The in vitro/in vivo discrepancy

Nanomedicine has a great potential to revolutionize the therapeutic landscape. However, up-to-date results obtained from in vitro experiments predict the in vivo performance of nanoparticles weakly or not at all. There is a need for in vitro experiments that better resemble the in vivo reality. As a result, animal experiments can be reduced, and potent in vivo candidates will not be missed. It is important to gain a deeper knowledge about nanoparticle characteristics in physiological environment. In this context, the protein corona plays a crucial role. Its formation process including driving forces, kinetics, and influencing factors has to be explored in more detail. There exist different methods for the investigation of the protein corona and its impact on physico-chemical and biological properties of nanoparticles, which are compiled and critically reflected in this review article. The obtained information about the protein corona can be exploited to optimize nanoparticles for in vivo application. Still the translation from in vitro to in vivo remains challenging. Functional in vitro screening under physiological conditions such as in full serum, in 3D multicellular spheroids/organoids, or under flow conditions is recommended. Innovative in vivo screening using barcoded nanoparticles can simultaneously test more than hundred samples regarding biodistribution and functional delivery within a single mouse.