Developing novel drug carriers for pulmonary delivery is necessary to achieve higher efficacy and consistency for treating pulmonary diseases while limiting off-target side effects that occur from ...alternative routes of administration. Metal–organic frameworks (MOFs) have recently emerged as a class of materials with characteristics well-suited for pulmonary drug delivery, with chemical tunability, high surface area, and pore size, which will allow for efficient loading of therapeutic cargo and deep lung penetration. UiO-66, a zirconium and terephthalic acid-based MOF, has displayed notable chemical and physical stability and potential biocompatibility; however, its feasibility for use as a pulmonary drug delivery vehicle has yet to be examined. Here, we evaluate the use of UiO-66 nanoparticles (NPs) as novel pulmonary drug delivery vehicles and assess the role of missing linker defects in their utility for this application. We determined that missing linker defects result in differences in NP aerodynamics but have minimal effects on the loading of model and therapeutic cargo, cargo release, biocompatibility, or biodistribution. This is a critical result, as it indicates the robust consistency of UiO-66, a critical feature for pulmonary drug delivery, which is plagued by inconsistent dosage because of variable properties. Not only that, but UiO-66 NPs also demonstrate pH-dependent stability, with resistance to degradation in extracellular conditions and breakdown in intracellular environments. Furthermore, the carriers exhibit high biocompatibility and low cytotoxicity in vitro and are well-tolerated in in vivo murine evaluations of orotracheally administered NPs. Following pulmonary delivery, UiO-66 NPs remain localized to the lungs before clearance over the course of seven days. Our results demonstrate the feasibility of using UiO-66 NPs as a novel platform for pulmonary drug delivery through their tunable NP properties, which allow for controlled aerodynamics and internalization-dependent cargo release while displaying remarkable pulmonary biocompatibility.
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Aerosolization of immunotherapies poses incredible potential for manipulating the local mucosal-specific microenvironment, engaging specialized pulmonary cellular defenders, and ...accessing mucosal associated lymphoid tissue to redirect systemic adaptive and memory responses. In this review, we breakdown key inhalable immunoengineering strategies for chronic, genetic, and infection-based inflammatory pulmonary disorders, encompassing the historic use of immunomodulatory agents, the transition to biological inspired or derived treatments, and novel approaches of complexing these materials into drug delivery vehicles for enhanced release outcomes. Alongside a brief description of key immune targets, fundamentals of aerosol drug delivery, and preclinical pulmonary models for immune response, we survey recent advances of inhaled immunotherapy platforms, ranging from small molecules and biologics to particulates and cell therapies, as well as prophylactic vaccines. In each section, we address the formulation design constraints for aerosol delivery as well as advantages for each platform in driving desirable immune modifications. Finally, prospects of clinical translation and outlook for inhaled immune engineering are discussed.
Computational Fluid-Particle Dynamics (CFPD) models have been employed to predict lung aerosol dynamics for decades, estimating the delivery efficiency of inhaled drugs into the tracheobronchial ...tree. However, existing CFPD models assume the glottis is static during the breathing cycle. Failing to capture the dynamic motion of the glottis may introduce significant errors in drug deposition estimations.
A novel CFPD model was developed with the capability of modeling the glottis motion using the dynamic mesh method. To explore the causal relationships between the glottis motion and the inhaled drug particle dynamics, simulations were performed to compare static and different dynamic glottis models in a subject-specific mouth-to-trachea geometry under idealized sinusoidal and realistic breathing waveforms. By defining the movement of each node in the glottis region using a generalized glottis motion function (GGMF) validated with clinical data, the abduction and adduction of the glottis were accurately described. Transient transport characteristics of inhaled particle-laden airflows were investigated and analyzed, including the glottis motion effect on the inhaled particles with the aerodynamic diameters from 0.1 to 10 μm.
Numerical results indicate that the static glottis assumption deviates the total deposition fraction predictions by more than 8% in relative differences. Compared with the CFPD models with the static glottis assumption, the dynamic glottis model can more realistically predict the complexity of the secondary flows near the vocal fold and the resultant particle depositions. Inter-subject variabilities of the glottis motion patterns were observed, and their influences on particle transport dynamics are not uniform. Parametric analyses also demonstrate that the maximum deformation ratio of the glottis is a key feature to describe whether the glottis motion can enhance or reduce particle depositions in the mouth-to-trachea region, over the static glottis model.
The glottis motion shows a significant influence on the accuracy of predicting inhaled particle dynamics, and it should be integrated into CFPD simulations validated by subject-specific glottis motion data from clinical studies in the future. Furthermore, the proposed dynamic glottis model has been demonstrated to be a computationally effective method to recover the physiologically realistic motions of the glottis, and ready to be added into the next-generation holistic virtual lung modeling approach.
•A clinically optimized dynamic glottis (DG) model has been developed.•A generalized glottis motion function (GGMF) has been proposed and validated.•The static glottis assumption leads to significant errors on lung aerosol dynamics prediction.•The glottis motion needs to be modeled to predict lung aerosol dynamics precisely.
Abstract Engineered nanoparticles have the potential to expand the breadth of pulmonary therapeutics, especially as respiratory vaccines. Notably, cationic nanoparticles have been demonstrated to ...produce superior local immune responses following pulmonary delivery; however, the cellular mechanisms of this increased response remain unknown. To this end, we systematically investigated the cellular response of lung APCS following pulmonary instillation of anionic and cationic charged nanoparticles. While nanoparticles of both surface charges were capable of trafficking to the draining lymph node and were readily internalized by alveolar macrophages, both CD11b and CD103 lung dendritic cell (DC) subtypes preferentially associated with cationic nanoparticles. Instillation of cationic nanoparticles resulted in the upregulation of Ccl2 and Cxc10 , which likely contributes to the recruitment of CD11b DCs to the lung. In total, these cellular mechanisms explain the increased efficacy of cationic formulations as a pulmonary vaccine carrier and provide critical benchmarks in the design of pulmonary vaccine nanoparticles.
UiO-66, a zirconium(IV) metal–organic framework composed of six-metal clusters and terephthalic acid ligands, displays excellent thermal and chemical stability and has functions in gas storage, ...catalysis, selective adsorption, and drug delivery. Though the stability of UiO-66 is highly advantageous, simultaneous synthetic control over particle size and defectiveness of UiO-66 remains difficult to attain. Using an acid-free solvothermal synthesis, we demonstrate that particle size, defectiveness, and inherent fluorescence of UiO-66 can be precisely tuned using the molar ligand-to-metal ratio, quantified water content, and reaction time during synthesis. These three synthetic handles allow for reproducible modulation of UiO-66 defectiveness between 0 and 12% and particle size between 20 and 120 nm, while maintaining high crystallinity in the nanoparticles that were formed. We also find that particle defectiveness is linked to common overestimation of particle size measurements obtained via dynamic light scattering and propose a model to correct elevated hydrodynamic diameter measurements. Finally, we report inherent fluorescence of nonfunctionalized UiO-66, which exhibits peak fluorescence at a wavelength of 390 nm following excitation at 280 nm and is maximized in large, defect-free particles. Overall, this synthetic approach and characterization of defect, size, and fluorescence represent new opportunities to tune the physiochemical properties of UiO-66.
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Targeted drug carriers are attractive for the delivery of therapeutics directly to the site of a disease, reducing systemic side effects and enhancing the efficacy of therapeutic ...molecules. However, the use of particulate carriers for drug delivery comes with its own set of challenges and barriers. Among these, a great deal of research effort has focused on protecting carriers from clearance by phagocytes via altering carrier surface chemistry, mostly with the use of polyethylene glycol (PEG) chain coatings. However, few papers have explored the effects of PEGylation on uptake by freshly-obtained primary human phagocytes in physiological conditions. In this work, we investigate the effect of PEGylation on particle uptake by primary human neutrophils in vitro and compare these effects to several cell lines and other model phagocytic cells systems. We find that human neutrophils in whole blood preferentially phagocytose PEGylated particles (e.g., ∼40% particle positive neutrophils for PEGylated versus ∼20% for carboxylated polystyrene microspheres) and that this effect is linked to factors present in human plasma. Model phagocytes internalized PEGylated particles less efficiently or equivalently to carboxylated particles in culture medium but preferentially phagocytosed PEGylated particles in the human plasma (e.g., ∼86% versus ∼63% PEGylated versus carboxylated particle positive cells, respectively). These findings have significant implications for the efficacy of PEGylation in designing long-circulating drug carriers, as well as the need for thorough characterization of drug carrier platforms in a wide array of in vitro and in vivo assays.
The work in this manuscript is highly significant to the field of drug delivery, as it explores in-depth the effects of polyethylene glycol (PEG) coatings, which are frequently used to prevent phagocytic clearance of particulate drug carriers, on the phagocytosis of such carriers by neutrophils, the most abundant leukocyte in blood circulation. Surprisingly, we find that PEGylation enhances uptake by primary human neutrophils, specifically in the presence of human plasma. This result suggests that PEGylation may not confer the benefits in humans once thought, and may help to explain why PEG has not become the “magic bullet” it was once thought to be in the field of particulate drug delivery.
The adoption of pulmonary vaccines to advantageously provide superior local mucosal protection against aerosolized pathogens has been faced with numerous logistical and practical challenges. One of ...these persistent challenges is the lack of effective vaccine adjuvants that could be well tolerated through the inhaled route of administration. Despite its widespread use as a vaccine adjuvant, aluminum salts (alum) are not well tolerated in the lung. To address this issue, we evaluated the use of porous aluminum (Al)-based metal-organic framework (MOF) nanoparticles (NPs) as inhalable adjuvants. We evaluate a suite of Al-based MOF NPs alongside alum including DUT-4, DUT-5, MIL-53 (Al), and MIL-101-NH
(Al). As synthesized, MOF NPs ranged between ~ 200 nm and 1 µm in diameter, with the larger diameter MOFs matching those of commercial alum. In vitro examination of co-stimulatory markers revealed that the Al-based MOF NPs activated antigen presenting cells more effectively than alum. Similar results were found during in vivo immunizations utilizing ovalbumin (OVA) as a model antigen, resulting in robust mucosal humoral responses for all Al MOFs tested. In particular, DUT-5 was able to elicit mucosal OVA-specific IgA antibodies that were significantly higher than the other MOFs or alum dosed at the same NP mass. DUT-5 also was uniquely able to generate detectable IgG2a titers, indicative of a cellular immune response and also had superior performance relative to alum at equivalent Al dosed in a reduced dosage vaccination study. All MOF NPs tested were generally well-tolerated in the lung, with only acute levels of cellular infiltrates detected and no Al accumulation; Al content was largely cleared from the lung and other organs at 28 days despite the two-dose regime. Furthermore, all MOF NPs exhibited mass median aerodynamic diameters (MMADs) of ~ 1.5-2.5 µm when dispersed from a generic dry powder inhaler, ideal for efficient lung deposition. While further work is needed, these results demonstrate the great potential for use of Al-based MOFs for pulmonary vaccination as novel inhalable adjuvants.
There is nothing like a global pandemic to motivate the need for improved respiratory treatments and mucosal vaccines. Stimulated by the COVID-19 pandemic, pulmonary aerosol drug delivery has seen a ...flourish of activity, building on the prior decades of innovation in particle engineering, inhaler device technologies, and clinical understanding. As such, the field has expanded into new directions and is working toward the efficient delivery of increasingly complex cargos to address a wider range of respiratory diseases. This review seeks to highlight recent innovations in approaches to personalize inhalation drug delivery, deliver complex cargos, and diversify the targets treated and prevented through pulmonary drug delivery. We aim to inform readers of the emerging efforts within the field and predict where future breakthroughs are expected to impact the treatment of respiratory diseases. Expected final online publication date for the
, Volume 26 is May 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Current facemask research focuses on material characterization and efficiency; however, facemasks are often not tested such that aerosol distributions are evaluated from the gaps in the sides, ...bottom, and nose areas. Poor evaluation methods could lead to misinformation on optimal facemasks use; a high-throughput, reproducible method which illuminates the issue of fit influencing aerosol transmission is needed. To this end, we have created an in vitro model to quantify particle transmission by mimicking exhalation aerosols in a 3D printed face-nose-mouth replica via a nebulizer and quantifying particle counts using a hand-held particle counter. A sewn, sewn with pipe cleaner nose piece, and sewn with a coffee filter facemask were used to evaluate current common homemade sewn facemask designs, benchmarked against industry standard surgical, N95 respirator tightly fit, and N95 respirator loosely fit facemasks. All facemasks have significantly reduced particle counts in front of the facemask, but the side and top of the facemask showed increases in particle counts over the no facemask condition at that same position, suggesting that some proportion of aerosols are being redirected to these gaps. An altered size distribution of aerosols that escape at the vulnerable positions was observed; escaped particles have larger count median diameters, with a decreased ratio of smaller to larger particles, possibly due to hygroscopic growth or aggregation. Of the homemade sewn facemasks, the facemask with a coffee filter insert performed the best at reducing escaped aerosols, with increased efficiency also observed for sewn masks with a pipe cleaner nose piece. Importantly, there were minimal differences between facemasks at increasing distances, which supports that social distance is a critical element in reducing aerosol transmission. This work brings to light the importance of quantifying particle count in positions other than directly in front of the facemask and identifies areas of research to be explored.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Significance To our knowledge, no other nano-based vaccine delivery platform has directly assessed the effects of nanoparticle charge on pulmonary vaccination without affecting other physio/chemical ...particle characteristics and/or antigen loading. The Particle Replication in Non-Wetting Templates nanoparticle fabrication process is unique in that it allows for isolation of charge as the sole variable in these studies while maintaining all other physical and chemical parameters constant. We find that positively charged nanoparticles induce robust mucosal and systemic antibody responses following pulmonary administration, whereas negatively charged nanoparticles fail to do so. Therefore, our studies underscore the importance of considering nanoparticle charge as a critical design parameter when generating pulmonary-based vaccines and may have implications for particulate vaccination through other routes of administration.
Pulmonary immunization enhances local humoral and cell-mediated mucosal protection, which are critical for vaccination against lung-specific pathogens such as influenza or tuberculosis. A variety of nanoparticle (NP) formulations have been tested preclinically for pulmonary vaccine development, yet the role of NP surface charge on downstream immune responses remains poorly understood. We used the Particle Replication in Non-Wetting Templates (PRINT) process to synthesize hydrogel NPs that varied only in surface charge and otherwise maintained constant size, shape, and antigen loading. Pulmonary immunization with ovalbumin (OVA)-conjugated cationic NPs led to enhanced systemic and lung antibody titers compared with anionic NPs. Increased antibody production correlated with robust germinal center B-cell expansion and increased activated CD4 ⁺ T-cell populations in lung draining lymph nodes. Ex vivo treatment of dendritic cells (DCs) with OVA-conjugated cationic NPs induced robust antigen-specific T-cell proliferation with ∼100-fold more potency than soluble OVA alone. Enhanced T-cell expansion correlated with increased expression of surface MHCII, T-cell coactivating receptors, and key cytokines/chemokine expression by DCs treated with cationic NPs, which were not observed with anionic NPs or soluble OVA. Together, these studies highlight the importance of NP surface charge when designing pulmonary vaccines, and our findings support the notion that cationic NP platforms engender potent humoral and mucosal immune responses.
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