mPEG-PLGA Nanoparticles Labelled with Loaded or Conjugated Rhodamine-B for Potential Nose-to-Brain Delivery

The role of polymer type and surfactant composition on the toxicological profile of nanoparticles: an in vitro comparative study

Nanotechnology is expanding rapidly, leading to the continual development of new applications. Therefore, it is crucial to understand the effects of nanoparticles (NPs) and their components to develop more efficient formulations with greater potential applications. Here, we evaluated the influence of polymer and surfactant composition on NP toxicity. Our results revealed significant variations in toxicity based on NP composition. The type of polymer used to prepare the NPs affects their properties, especially in terms of cell tolerance. Notably, cell viability ranged from 6% to 100% depending on the NPs' composition. In general, NPs based on Eudragit® RL 100 exhibited greater cytotoxicity and hemolysis rates than those based on PCL, PLGA, and chitosan. This highlights the critical role of polymer selection in determining toxicity. Additionally, including Span 80® in the NP matrix amplified its toxic effects, which emphasizes the importance of surfactant choice in NP design. Both nanospheres and nanocapsules based on the same polymer displayed comparable toxicological profiles. Although smaller NPs exhibited higher toxicity, a direct correlation between size and toxicity could not be established, since the increased toxicity of smaller NPs was primarily attributed to the presence of Span 80® in the composition. Finally, all formulations, except the nanospheres based on Eudragit® RL 100, maintained colloidal stability in a protein-rich environment, indicating that no secondary structures were formed. Therefore, our data suggest that NP constituents can critically contribute to its toxicity, highlighting the importance of toxicological and safety studies to better understand the effects of nanoformulations.

Gypenoside A-loaded mPEG-PLGA nanoparticles ameliorate high-glucose-induced retinal microvasculopathy by inhibiting ferroptosis

Diabetic retinopathy (DR) is one of the chronic microvascular complications of type 2 diabetes mellitus (T2DM), which will cause retinal detachment and blindness without ideal therapies. Gypenoside A (GPA) are the main bioactive compound from Gynostemma pentaphyllum, and have various pharmacological effects. However, it suffered from poor bioavailability and potential cardiotoxicity in the clinical application. To overcome those limitations, in this study, nearly spherical nanoparticles (GPA-NP) with a mean particle size of 140.6 ± 22.4 nm were prepared by encapsulating GPA into mPEG-PLGA. This encapsulation efficiency was 84.4 ± 6.9 %, and the drug load was 4.02 %±0.35 %. The results showed that GPA-NP displayed more prolonged GPA release and higher bioavailability in vitro than GPA. GPA-NP obviously reduced the levels of oxidative stress markers and inflammatory cytokines in both retinal tissues of DR mice and high glucose-exposed HRMEC better than GPA alone. Mechanismly, GPA blocked the Nrf2-Keap1 interaction by binding with Kelch domain of Keap1 via alkyl and hydrogen bonds. Therefore, GPA-NP exerted more potent protectivity effects against high glucose-induced retinal microvascular endothelial ferroptosis in vitro and in vivo by activating Nrf2/HO-1/GPX4 pathway. It could be a promising therapeutic agent for preventing DR.

Preparation and Pharmacokinetics of Brain-Targeted Nanoliposome Loaded with Rutin

Rutin is a flavonoid compound with potential for treating Alzheimer's disease, preventing brain damage, mitigating cerebral ischemia-reperfusion injury, and exhibiting anti-glioblastoma activity. However, its efficacy is limited by its low solubility, poor bioavailability, and limited permeability across the blood-brain barrier (BBB). To enhance the bioavailability and brain-targeting ability of Rutin, transferrin-modified Rutin liposome (Tf-Rutin-Lip) was developed using liposomes as a delivery system. Rutin liposomes were prepared using the thin-film dispersion method, and the preparation conditions were optimized using the response surface methodology. Then, transferrin (Tf) was incorporated into the liposomes through covalent modification, yielding Tf-Rutin liposomes. The toxicity of these liposomes on bEnd.3 cells, as well as their impact on the tight junctions of these cells, was rigorously evaluated. Additionally, in vitro and in vivo experiments were conducted to validate the brain-targeting efficacy of the Tf-Rutin liposomes. A susceptible detection method was developed to characterize the pharmacokinetics of Tf-Rutin-Lip further. The optimized conditions for the preparation of Tf-Rutin-Lip were determined as follows: a lipid-to-cholesterol ratio of 4.63:1, a drug-to-lipid ratio of 1:45.84, a preparation temperature of 42.7 °C, a hydration volume of 20 mL, a sonication time of 10 min, a surfactant concentration of 80 mg/mL, a DSPE-MPEG-2000 concentration of 5%, and a DSPE-PEG2000-COOH to DSPE-MPEG-2000 molar ratio of 10%. The liposomes did not affect the cell activity of bEnd.3 cells at 24 h and did not disrupt the tight junction of the blood-brain barrier. Tf-modified liposomes were taken up by bEnd.3 cells, which, in turn, passed through the BBB, thus improving liposomal brain targeting. Furthermore, the results of pharmacokinetic experiments showed that the Cmax, AUC0-∞, AUC0-t, MRT0-∞, and t1/2 of Tf-Rutin-Lip increased 1.99-fold, 2.77-fold, 2.58-fold, 1.26-fold, and 1.19-fold compared to those of free Rutin solution, respectively. These findings suggest that Tf-Rutin-Lip is brain-targeted and may enhance the efficacy of Rutin in the treatment of brain disorders.

A Cell-Based Nasal Model for Screening the Deposition, Biocompatibility, and Transport of Aerosolized PLGA Nanoparticles

The olfactory region of the nasal cavity directly links the brain to the external environment, presenting a potential direct route to the central nervous system (CNS). However, targeting drugs to the olfactory region is challenging and relies on a combination of drug formulation, delivery device, and administration technique to navigate human nasal anatomy. In addition, in vitro and in vivo models utilized to evaluate the performance of nasal formulations do not accurately reflect deposition and uptake in the human nasal cavity. The current study describes the development of a respirable poly(lactic-co-glycolic acid) nanoparticle (PLGA NP) formulation, delivered via a pressurized metered dose inhaler (pMDI), and a cell-containing three-dimensional (3D) human nasal cast model for deposition assessment of nasal formulations in the olfactory region. Fluorescent PLGA NPs (193 ± 3 nm by dynamic light scattering) were successfully formulated in an HFA134a-based pMDI and were collected intact following aerosolization. RPMI 2650 cells, widely employed as a nasal epithelial model, were grown at the air-liquid interface (ALI) for 14 days to develop a suitable barrier function prior to exposure to the aerosolized PLGA NPs in a glass deposition apparatus. Direct aerosol exposure was shown to have little effect on cell viability. Compared to an aqueous NP suspension, the transport rate of the aerosolized NPs across the RPMI 2650 barrier was higher at all time points indicating the potential advantages of delivery via aerosolization and the importance of employing ALI cellular models for testing respirable formulations. The PLGA NPs were then aerosolized into a 3D-printed human nasal cavity model with an insert of ALI RPMI 2650 cells positioned in the olfactory region. Cells remained highly viable, and there was significant deposition of the fluorescent NPs on the ALI cultures. This study is a proof of concept that pMDI delivery of NPs is a viable means of targeting the olfactory region for nose-to-brain drug delivery (NTBDD). The cell-based model allows not only maintenance under ALI culture conditions but also sampling from the basal chamber compartment; hence, this model could be adapted to assess drug deposition, uptake, and transport kinetics in parallel under real-life settings.

Construction of SLC16A1/3 Targeted Gallic Acid-Iron-Embelin Nanoparticles for Regulating Glycolysis and Redox Pathways in Cervical Cancer

SLC16A1 and SLC16A3 (SLC16A1/3) are highly expressed in cervical cancers and associated with the malignant biological behavior of cancer. SLC16A1/3 is the critical hub for regulating the internal and external environment, glycolysis, and redox homeostasis in cervical cancer cells. Inhibiting SLC16A1/3 provides a new thought to eliminate cervical cancer effectively. There are few reports on effective treatment strategies to eliminate cervical cancer by simultaneously targeting SLC16A1/3. GEO database analysis and quantitative reverse transcription polymerase chain reaction experiment were used to confirm the high expression of SLC16A1/3. The potential inhibitor of SLC16A1/3 was screened from Siwu Decoction by using network pharmacology and molecular docking technology. The mRNA levels and protein levels of SLC16A1/3 in SiHa and HeLa cells treated by Embelin (EMB) were clarified, respectively. Furthermore, the Gallic acid-iron (GA-Fe) drug delivery system was used to improve its anti-cancer performance. Compared with normal cervical cells, SLC16A1/3 mRNA was over-expressed in SiHa and HeLa cells. Through the analysis of Siwu Decoction, a simultaneously targeted SLC16A1/3 inhibitor EMB was discovered. It was found for the first time that EMB promoted lactic acid accumulation and further induced redox dyshomeostasis and glycolysis disorder by simultaneously inhibiting SLC16A1/3. The gallic acid-iron-Embelin (GA-Fe@EMB) drug delivery system delivered EMB, which had a synergistic anti-cervical cancer effect. Under the irradiation of a near-infrared laser, the GA-Fe@EMB could elevate the temperature of the tumor area effectively. Subsequently, EMB was released and mediated the lactic acid accumulation and the GA-Fe nanoparticle synergistic Fenton reaction to promote ROS accumulation, thereby increasing the lethality of the nanoparticles on cervical cancer cells. GA-Fe@EMB can target cervical cancer marker SLC16A1/3 to regulate glycolysis and redox pathways, synergistically with photothermal therapy, which provides a new avenue for the synergistic treatment of malignant cervical cancer.

Sustained-Release Powders Based on Polymer Particles for Pulmonary Delivery of Beclomethasone Dipropionate in the Treatment of Lung Inflammation

Inhaled corticosteroids are the mainstay in the management of lung inflammation associated to chronic lung diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Nonetheless, available inhalation products are mostly short-acting formulations that require frequent administrations and do not always produce the desired anti-inflammatory effects. In this work, the production of inhalable beclomethasone dipropionate (BDP) dry powders based on polymeric particles was attempted. As starting material, the PHEA-g-RhB-g-PLA-g-PEG copolymer was chosen, obtained by grafting 0.6, 2.4 and 3.0 mol%, respectively, of rhodamine (RhB), polylactic acid (PLA) and polyethylene glycol 5000 (PEG) on alpha,beta-poly(N-2-hydroxyethyl)DL-aspartamide (PHEA). The drug was loaded into the polymeric particles (MP) as an inclusion complex (CI) with hydroxypropyl-cyclodextrin (HP-β-Cyd) (at a stoichiometric ratio of 1:1) or as free form. The spray-drying (SD) process to produce MPs was optimized by keeping the polymer concentration (0.6 wt/vol%) constant in the liquid feed and by varying other parameters such as the drug concentration. The theoretical aerodynamic diameter (d_aer) values among the MPs are comparable and potentially suitable for inhalation, as confirmed also through evaluation of the experimental mass median aerodynamic diameter (MMAD_exp). BDP shows a controlled release profile from MPs that is significantly higher (more than tripled) than from Clenil^®. In vitro tests on bronchial epithelial cells (16HBE) and adenocarcinomic human alveolar basal epithelial cells (A549) showed that all the MP samples (empty or drug-loaded) were highly biocompatible. None of the systems used induced apoptosis or necrosis. Moreover, the BDP loaded into the particles (BDP-Micro and CI-Micro) was more efficient than free BDP to counteract the effects of cigarette smoke and LPS on release of IL-6 and IL-8.

Melatonin loaded hybrid nanomedicine: DoE approach, optimization and in vitro study on diabetic retinopathy model

Melatonin (MEL) is a pleiotropic neurohormone of increasing interest as a neuroprotective agent in ocular diseases. Improving the mucoadhesiveness is a proposed strategy to increase the bioavailability of topical formulations. Herein, the design and optimization of MEL-loaded lipid-polymer hybrid nanoparticles (mel-LPHNs) using Design of Experiment (DoE) was performed. LPHNs consisted of PLGA-PEG polymer nanoparticles coated with a cationic lipid-shell. The optimized nanomedicine showed suitable size for ophthalmic administration (189.4 nm; PDI 0.260) with a positive surface charge (+39.8 mV), high encapsulation efficiency (79.8 %), suitable pH and osmolarity values, good mucoadhesive properties and a controlled release profile. Differential Scanning Calorimetry and Fourier-Transform Infrared Spectroscopy confirmed the encapsulation of melatonin in the systems and the interaction between lipids and polymer matrix. Biological evaluation in an in vitro model of diabetic retinopathy demonstrated enhanced neuroprotective and antioxidant activities of mel-LPHNs, compared to melatonin aqueous solution at the same concentration (0.1 and 1 μM). A modified Draize test was performed to assess the ocular tolerability of the formulation showing no signs of irritation. To the best our knowledge, this study reported for the first time the development of mel-LPHNs, a novel and safe hybrid platform suitable for the topical management of retinal diseases.

Bridging nanoplatform and vaccine delivery, a landscape of strategy to enhance nasal immunity

Vaccination is an urgently needed and effective option to address epidemic, cancers, allergies, and other diseases. Nasal administration of vaccines offers many benefits over needle-based injection including high compliance and less risk of infection. Inactivated or attenuated vaccines as convention vaccine present potential risks of pathogenic virulence reversal, the focus of nasal vaccine development has shifted to the use of next-generation (subunit and nucleic acid) vaccines. However, subunit and nucleic acid vaccine intranasally have numerous challenges in development and utilization due to mucociliary clearance, mucosal epithelial tight junction, and enzyme/pH degradation. Nanoplatforms as ideal delivery systems, with the ability to enhance the retention, penetration, and uptake of nasal mucosa, shows great potential in improving immunogenic efficacy of nasal vaccine. This review provides an overview of delivery strategies for overcoming nasal barrier, including mucosal adhesion, mucus penetration, targeting of antigen presenting cells (APCs), enhancement of paracellular transportation. We discuss methods of enhancing antigen immunogenicity by nanoplatforms as immune-modulators or multi-antigen co-delivery. Meanwhile, we describe the application status and development prospect of nanoplatforms for nasal vaccine administration. Development of nanoplatforms for vaccine delivery via nasal route will facilitate large-scale and faster global vaccination, helping to address the threat of epidemics.

Biopolymer Nanoparticles for Nose-to-Brain Drug Delivery: A New Promising Approach for the Treatment of Neurological Diseases

Diseases affecting the central nervous system (CNS) are among the most disabling and the most difficult to cure due to the presence of the blood-brain barrier (BBB) which represents an impediment from a therapeutic and diagnostic point of view as it limits the entry of most drugs. The use of biocompatible polymer nanoparticles (NPs) as vehicles for targeted drug delivery to the brain arouses increasing interest. However, the route of administration of these vectors remains critical as the drug must be delivered without being degraded to achieve a therapeutic effect. An innovative approach for the administration of drugs to the brain using polymeric carriers is represented by the nose-to-brain (NtB) route which involves the administration of the therapeutic molecule through the neuro-olfactory epithelium of the nasal mucosa. Nasal administration is a non-invasive approach that allows the rapid transport of the drug directly to the brain and minimizes its systemic exposure. To date, many studies involve the use of polymer NPs for the NtB transport of drugs to the brain for the treatment of a whole series of disabling neurological diseases for which, as of today, there is no cure. In this review, various types of biodegradable polymer NPs for drug delivery to the brain through the NtB route are discussed and particular attention is devoted to the treatment of neurological diseases such as Glioblastoma and neurodegenerative diseases.

Polymeric Nanoparticles in Brain Cancer Therapy: A Review of Current Approaches

Translation of novel therapies for brain cancer into clinical practice is of the utmost importance as primary brain tumors are responsible for more than 200,000 deaths worldwide each year. While many research efforts have been aimed at improving survival rates over the years, prognosis for patients with glioblastoma and other primary brain tumors remains poor. Safely delivering chemotherapeutic drugs and other anti-cancer compounds across the blood-brain barrier and directly to tumor cells is perhaps the greatest challenge in treating brain cancer. Polymeric nanoparticles (NPs) are powerful, highly tunable carrier systems that may be able to overcome those obstacles. Several studies have shown appropriately-constructed polymeric NPs cross the blood-brain barrier, increase drug bioavailability, reduce systemic toxicity, and selectively target central nervous system cancer cells. While no studies relating to their use in treating brain cancer are in clinical trials, there is mounting preclinical evidence that polymeric NPs could be beneficial for brain tumor therapy. This review includes a variety of polymeric NPs and how their associated composition, surface modifications, and method of delivery impact their capacity to improve brain tumor therapy.

Fluorescent labeling as a strategy to evaluate uptake and transport of polymeric nanoparticles in plants

The use of biodegradable nanopolymers in agriculture offers an excellent alternative for the efficient delivery of agrochemicals that promote plant protection and development. However, tracking of these systems inside plants requires complex probe tagging strategies. In addition to providing a basis for better understanding such nanostructures to optimize delivery system design, these probes allow monitoring the migration of nanoparticles through plant tissues, and determine accumulation sites. Thus, these probes are powerful tools that can be used to quantify and visualize nanoparticle accumulation in plant cells and tissues. This review is an overview of the methods involved in labeling nanocarriers, mainly based on polymeric matrices, for the delivery of nanoagrochemicals and the recent advances in this field.

Fluorescent Nanosystems for Drug Tracking and Theranostics: Recent Applications in the Ocular Field

The greatest challenge associated with topical drug delivery for the treatment of diseases affecting the posterior segment of the eye is to overcome the poor bioavailability of the carried molecules. Nanomedicine offers the possibility to overcome obstacles related to physiological mechanisms and ocular barriers by exploiting different ocular routes. Functionalization of nanosystems by fluorescent probes could be a useful strategy to understand the pathway taken by nanocarriers into the ocular globe and to improve the desired targeting accuracy. The application of fluorescence to decorate nanocarrier surfaces or the encapsulation of fluorophore molecules makes the nanosystems a light probe useful in the landscape of diagnostics and theranostics. In this review, a state of the art on ocular routes of administration is reported, with a focus on pathways undertaken after topical application. Numerous studies are reported in the first section, confirming that the use of fluorescent within nanoparticles is already spread for tracking and biodistribution studies. The first section presents fluorescent molecules used for tracking nanosystems’ cellular internalization and permeation of ocular tissues; discussions on the classification of nanosystems according to their nature (lipid-based, polymer-based, metallic-based and protein-based) follows. The following sections are dedicated to diagnostic and theranostic uses, respectively, which represent an innovation in the ocular field obtained by combining dual goals in a single administration system. For its great potential, this application of fluorescent nanoparticles would experience a great development in the near future. Finally, a brief overview is dedicated to the use of fluorescent markers in clinical trials and the market in the ocular field.

Robust Chemical Strategy for Stably Labeling Polyester-Based Nanoparticles with BODIPY Fluorophores

Aliphatic polyesters are among materials most extensively used for producing biodegradable polymeric nanoparticles currently in development as delivery carriers and imaging agents for a range of biomedical applications. Their clinical translation requires robust particle labeling methodologies that allow reliably monitoring the fate of these formulations in complex biological environments. In the present study, a practical and versatile synthetic strategy providing conjugates of poly(D,L-lactide) representative of this class of polymers with BODIPY fluorophores varying in functional groups and excitation/emission maxima was investigated as a tool for making traceable nanoparticles. Polymer-probe conjugation was accomplished by carbodiimide-induced and 4-(dimethylamino)pyridinium 4-toluenesulfonate-catalyzed esterification of the polymer's terminal hydroxyl group, either directly with a carboxy-functionalized fluorophore or with amine-protected amino acids (Boc-glycine or Boc-6-aminohexanoic acid). In the latter case, the amino acid-derivatized polymeric precursors were reacted with amine-reactive BODIPY dyes after the removal of the protective group. Unlike nanoparticles encapsulating a strongly hydrophobic BODIPY_505/515 (logP_o/w = 4.3), nanoparticles labeled covalently with its carboxy-functionalized analogue (BODIPY FL) demonstrated stable particle-tracer association under perfect sink conditions. Furthermore, in contrast to the encapsulated dye rapidly partitioning from particles onto cell membranes but not stably retained by cultured cells, the internalization of the covalently attached probe was an irreversible process requiring the presence of serum, consistent with active nanoparticle uptake by endocytosis. In conclusion, the conjugation of particle-forming polymers with BODIPY fluorophores offers an effective and accessible labeling strategy for making traceable polyester-based biodegradable nanoparticles and is expected to facilitate their development and optimization as therapeutic carriers and diagnostic agents.

Novel Nanoparticles Based on N,O-Carboxymethyl Chitosan-Dopamine Amide Conjugate for Nose-to-Brain Delivery

A widely investigated approach to bypass the blood brain barrier is represented by the intranasal delivery of therapeutic agents exploiting the olfactory or trigeminal connections nose-brain. As for Parkinson’s disease (PD), characterized by dopaminergic midbrain neurons degeneration, currently there is no disease modifying therapy. Although several bio-nanomaterials have been evaluated for encapsulation of neurotransmitter dopamine (DA) or dopaminergic drugs in order to restore the DA content in parkinsonian patients, the premature leakage of the therapeutic agent limits this approach. To tackle this drawback, we undertook a study where the active was linked to the polymeric backbone by a covalent bond. Thus, novel nanoparticles (NPs) based on N,O-Carboxymethylchitosan-DA amide conjugate (N,O-CMCS-DA) were prepared by the nanoprecipitation method and characterized from a technological view point, cytotoxicity and uptake by Olfactory Ensheating Cells (OECs). Thermogravimetric analysis showed high chemical stability of N,O-CMCS-DA NPs and X-ray photoelectron spectroscopy evidenced the presence of amide linkages on the NPs surface. MTT test indicated their cytocompatibility with OECs, while cytofluorimetry and fluorescent microscopy revealed the internalization of labelled N,O-CMCS-DA NPs by OECs, that was increased by the presence of mucin. Altogether, these findings seem promising for further development of N,O-CMCS-DA NPs for nose-to-brain delivery application in PD.