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The subcellular distribution of cargoes plays a crucial role in determining cell fate and therapeutic efficacy. However, achieving the precise delivery of therapeutics to specific intracellular targets remains a significant challenge. Here, we present a trimodular and acid/enzyme-gated nanoplatform (TAEN) that undergoes disassembly within acidic endosomes and then is cleaved by lysosomal cathepsin B to facilitate efficient and targeted transport of released cargoes into mitochondria compartments. By utilizing this nanovehicle, we successfully achieve selective sorting of photosensitizer molecules into mitochondria with a colocalization coefficient of up to 0.98, leading to the generation of reactive oxygen species stress specifically within the mitochondria for potent pyroptosis-based cancer therapy. The induction of mitochondrial stress triggers the intrinsic apoptotic pathway as well as caspase-3/gasdermin-E (GSDME) cascade, resulting in an enhanced cancer cell killing efficacy by nearly 2 orders of magnitude as compared to lysosomal stress. Furthermore, due to its superior capability to stimulate both innate and adaptive immune responses, our mitochondria-sorted nanophotosensitizer exhibits robust antitumor immune efficacy in multiple tumor-bearing mice models. This study not only provides insights into engineering nanomedicines for subcellular targeted delivery but also offers a valuable toolkit for advanced research in the field of nanobiology at subcellular resolution.

NIR-II fluorescence imaging-guided photothermal therapy (PTT) has been widely investigated due to its great application potential in tumor theranostics. PTT is an effective and non-invasive tumor treatment method that can adapt to tumor hypoxia; nevertheless, simple and effective strategies are still desired to develop new materials with excellent PTT properties to meet clinical requirements. In this work, we developed a bromine-substitution strategy to enhance the PTT of A-D-A'-D-A π-conjugated molecules. The experimental results reveal that bromine substitution can notably enhance the absorptivity (ϵ) and photothermal conversion efficiency (PCE) of the π-conjugated molecules, resulting in the brominated molecules generating two times more heat (ϵ 808 nm ×PCE) than their unsubstituted counterpart. We disclose that the enhanced photothermal properties of bromine-substituted π-conjugated molecules are a combined outcome of the heavy-atom effect, enhanced ICT effect, and more intense bromine-mediate intermolecular π-π stacking. Finally, the NIR-II tumor imaging capability and efficient PTT tumor ablation of the brominated π-conjugated materials demonstrate that bromine substitution is a promising strategy for developing future high-performance NIR-II imaging-guided PTT agents., (© 2023 Wiley-VCH GmbH.)

Chitosan, as a promising gene nanocarrier for enhancing RNA interference (RNAi) efficiency, displays tremendous application prospects in addressing dsRNA delivery concerns. However, the molecular mechanism of chitosan/dsRNA polyplex nanoparticles (PNs) for advancing dsRNA delivery efficiency remains largely unknown. Here, chitosan/dsRNA PNs were prepared by an electrostatic attraction method. The results showed that the chitosan/dsRNA PNs significantly advance stability, and cellular uptake efficiency of dsRNA, and RNAi efficiency. RNA-Seq and qPCR assays further revealed that chitosan/dsRNA PNs upregulated the key clathrin heavy chain (CHC) gene for activating clathrin-dependent endocytosis (CDE) pathway. Additionally, inhibition of CDE hindered the robust RNAi responses of chitosan/dsRNA PNs using an inhibitor (chlorpromazine) and an RNAi-of-RNAi strategy. Ultimately, microscale thermophoresis assay confirmed that chitosan/dsRNA PNs directly bound to CHC protein, which was a core component in CDE, to advance RNAi efficiency. To our knowledge, our findings firstly illuminate the molecular mechanism how chitosan nanoparticles-based RNAi deliver dsRNA for enhancing RNAi efficiency. Above mechanism will advance the extensive utilization of nanocarrier-based RNAi in pest management and gene delivery., Competing Interests: Declaration of competing interest The authors declare no competing financial interests., (Copyright © 2023. Published by Elsevier B.V.)

Metal-organic frameworks (MOFs) with periodically arranged porphyrinic linkers avoiding the self-quenching issue of porphyrins in photodynamic therapy (PDT) have been widely applied. However, the porphyrinic MOFs still face challenges of poor stability under physiological conditions and limited photodynamic efficiency by the hypoxia condition of tumors. Herein, we fabricate the MOF@MOF structure with a protective MOF shell to improve the stability and relieve the hypoxia condition of tumors for sensitized PDT. Under protection of the MOF shell, the MOF@MOF structure can keep intact for 96 h under physiological conditions. Consequently, the tumoral accumulation efficiency is two folds of the MOF core. Furthermore, the MOF shell decomposes under acidic environment, and the loaded inhibitor of mitochondria pyruvate carrier (7-amino carboxycoumarins-2, 7ACC2) will be released. 7ACC2 inhibits the mitochondrial pyruvate influx and simultaneously blocks glucose and lactate from fueling the mitochondrial respiration, thereupon relieving the hypoxia condition of tumors. Under a 5-min laser irradiation, the 7ACC2 carrying MOF@MOF nanoplatforms induced doubled cellular apoptosis and reduced 70% of the tumor growth compared with the cargo-free MOF@MOF. In summary, the design of this stable and hypoxia self-relievable MOF@MOF nanoplatform will enlighten the future development of MOF-based nanomedicines and PDT. STATEMENT OF SIGNIFICANCE: Though widely used for photodynamic therapy (PDT) in previous studies, porphyrinic metal-organic frameworks (MOFs) still face challenges in poor stability under physiological conditions and limited photodynamic efficiency due to the hypoxia condition of tumors. In order to solve these problems, (1) we develop the MOF@MOF strategy to improve the physiological stability; (2) an inhibitor of mitochondria pyruvate carrier, 7-amino carboxycoumarins-2 (7ACC2), is loaded to inhibit the mitochondrial pyruvate influx and simultaneously block glucose and lactate from fueling the mitochondrial respiration, thereupon relieving the hypoxia condition of tumors. In comparison with previous studies, our strategy simultaneously improves stability and overcomes the limited PDT efficiency in the hypoxia tumor tissue, which will enlighten the future development of MOF-based nanomedicines and PDT., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interest., (Copyright © 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Tumour-associated macrophages (TAMs), as one of the most abundant tumour-infiltrating immune cells, play a pivotal role in tumour antigen clearance and immune suppression. M2-like TAMs present a heightened lysosomal acidity and protease activity, limiting an effective antigen cross-presentation. How to selectively reprogram M2-like TAMs to reinvigorate anti-tumour immune responses is challenging. Here, we report a pH-gated nanoadjuvant (PGN) that selectively targets the lysosomes of M2-like TAMs in tumours rather than the corresponding organelles from macrophages in healthy tissues. Enabled by the PGN nanotechnology, M2-like TAMs are specifically switched to a M1-like phenotype with attenuated lysosomal acidity and cathepsin activity for improved antigen cross-presentation, thus eliciting adaptive immune response and sustained tumour regression in tumour-bearing female mice. Our findings provide insights into how to specifically regulate lysosomal function of TAMs for efficient cancer immunotherapy., (© 2023. Springer Nature Limited.)

Nanorobotic manipulation to access subcellular organelles remains unmet due to the challenge in achieving intracellular controlled propulsion. Intracellular organelles, such as mitochondria, are an emerging therapeutic target with selective targeting and curative efficacy. We report an autonomous nanorobot capable of active mitochondria-targeted drug delivery, prepared by facilely encapsulating mitochondriotropic doxorubicin-triphenylphosphonium (DOX-TPP) inside zeolitic imidazolate framework-67 (ZIF-67) nanoparticles. The catalytic ZIF-67 body can decompose bioavailable hydrogen peroxide overexpressed inside tumor cells to generate effective intracellular mitochondriotropic movement in the presence of TPP cation. This nanorobot-enhanced targeted drug delivery induces mitochondria-mediated apoptosis and mitochondrial dysregulation to improve the in vitro anticancer effect and suppression of cancer cell metastasis, further verified by in vivo evaluations in the subcutaneous tumor model and orthotopic breast tumor model. This nanorobot unlocks a fresh field of nanorobot operation with intracellular organelle access, thereby introducing the next generation of robotic medical devices with organelle-level resolution for precision therapy.

Chemodynamic therapy (CDT) relies on the transformation of intracellular hydrogen peroxide (H 2 O 2 ) to hydroxyl radicals (·OH) with higher toxicity under the catalysis of Fenton/Fenton-like reagents, which amplifies the oxidative stress and induces significant cellular apoptosis. However, the CDT efficacy is generally limited by the overexpressed GSH and insufficient endogenous H 2 O 2 in tumors. Co-delivery of Cu 2+ and glucose oxidase (GOD) can lead to a Cu 2+ /Cu + circulation to realize GSH depletion and amplify the Fenton-like reaction. pH-responsive metal-organic frameworks (MOFs) are the optical choice to deliver Fenton/Fenton-like ions to tumors. However, considering that the aqueous condition is requisite for GOD encapsulation, it is challenging to abundantly dope Cu 2+ in ZIF-8 MOF nanoparticles in aqueous conditions due to the ease of precipitation and enlarged crystal size. In this work, a robust one-pot biomimetic mineralization method using excessive ligand precursors in aqueous conditions is developed to synthesize GOD@Cu-ZIF-8. Copper ions abundantly doped to the GOD@Cu-ZIF-8 can eliminate GSH to produce Cu + , which is further proceeded to the Fenton-like reaction in the presence of GOD-catalyzed H 2 O 2 . Through breaking the tumor microenvironment homeostasis and producing an enhanced CDT effect, the promising antitumor capability of GOD@Cu-ZIF-8 was evidenced by the experiments both in vitro and in vivo .

Pulmonary delivery of small interfering RNA (siRNA) using nanoparticle-based delivery systems is promising for local treatment of respiratory diseases. We designed dry powder inhaler formulations of siRNA-loaded lipid-polymer hybrid nanoparticles (LPNs) with aerosolization properties optimized for inhalation therapy. Interactions between LPNs and pulmonary surfactant (PS) determine the fate of inhaled LPNs, but interaction mechanisms are unknown. Here we used surface-sensitive techniques to study how physicochemical properties and pathological microenvironments influence interactions between siRNA-loaded LPNs and supported PS layers. PS was deposited on SiO 2 surfaces as single bilayer or multilayers and characterized using quartz crystal microbalance with dissipation monitoring and Fourier-transform infrared spectroscopy with attenuated total reflection. Immobilization of PS as multilayers, resembling the structural PS organization in the alveolar subphase, effectively reduced the relative importance of interactions between PS and the underlying surface. However, the binding affinity between PS and LPNs was identical in the two models. The physicochemical LPN properties influenced the translocation pathways and retention time of LPNs. Membrane fluidity and electrostatic interactions were decisive for the interaction strength between LPNs and PS. Experimental conditions reflecting pathological microenvironments promoted LPN deposition. Hence, these results shed new light on design criteria for LPN transport through the air-blood barrier., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Precise monitoring of the subtle pH fluctuation during biological events remains a big challenge. Previously, we reported an ultra-pH-sensitive (UPS) nanoprobe library with a sharp pH response using co-polymerization of two tertiary amine-containing monomers with distinct pK a . Currently, we have generalized the UPS nanoparticle library with tunable pH transitions (pH t ) by copolymerization of a tertiary amine-containing monomer with a series of non-ionizable monomers. The pH t of nanoparticles is fine-tuned by the non-ionizable monomers with different hydrophobicity. Each non-ionizable monomer presents a constant contribution to pH tunability regardless of tertiary amine-containing monomers. Based on this strategy, we produced two libraries of nanoprobes with continuous pH t covering the entire physiological pH range (5.0-7.4) for fluorescent imaging of endosome maturation and cancers. This generalized strategy provides a powerful toolkit for biological studies and cancer theranostics., (© 2022 Wiley-VCH GmbH.)

Efficient delivery of payload to intracellular targets has been identified as the central principle for nanomedicine development, while the extracellular targets are equally important for cancer treatment. Notably, the contribution of extracellularly distributed nanoparticles to therapeutic outcome is far from being understood. Herein, we develop a pH/light dual-responsive monochromatic ratiometric imaging nanoparticle (MRIN), which functions through sequentially lighting up the intracellular and extracellular fluorescence signals by acidic endocytic pH and near-infrared light. Enabled by MRIN nanotechnology, we accurately quantify the extracellular and intracellular distribution of nanoparticles in several tumor models, which account for 65-80% and 20-35% of total tumor exposure, respectively. Given that the majority of nanoparticles are trapped in extracellular regions, we successfully dissect the contribution of extracellularly distributed nanophotosensitizer to therapeutic efficacy, thereby maximize the treatment outcome. Our study provides key strategies to precisely quantify nanocarrier microdistribtion and engineer multifunctional nanomedicines for efficient theranostics., (© 2022. The Author(s).)

Toll-like receptor (TLR) agonists are potent immune-stimulators that hold great potential in vaccine adjuvants as well as cancer immunotherapy. However, TLR agonists in free form are prone to be eliminated quickly by the circulatory system and cause systemic inflammation side effects. It remains a challenge to achieve precise release of TLR7/8 agonist in the native form at the receptor site in the endosomal compartments while keeping stable encapsulation and inactive in nontarget environment. Here, we report a pH-/enzyme-responsive TLR7/8 agonist-conjugated nanovaccine (TNV), which responds intelligently to the acidic environment and cathepsin B in the endosome, precisely releases TLR7/8 agonist to activate its receptor signaling at the endosomal membrane, stimulates DCs maturation, and provokes specific cellular immunity. In vivo experiments demonstrate outstanding prophylactic and therapeutic efficacy of TNV in mouse melanoma and colon cancer. The endosome-targeted responsive nanoparticle strategy provides a potential delivery toolbox of adjuvants to advance the development of tumor nanovaccines.

Recalcitrant respiratory tract infections caused by bacteria have emerged as one of the greatest health challenges worldwide. Aerosolized antimicrobial therapy is becoming increasingly attractive to combat such infections, as it allows targeted delivery of high drug concentrations to the infected organ while limiting systemic exposure. However, successful aerosolized antimicrobial therapy is still challenged by the diverse biological barriers in infected lungs. Nanoparticle-mediated pulmonary drug delivery is gaining increasing attention as a means to overcome the biological barriers and accomplish site-specific drug delivery by controlling release of the loaded drug(s) at the target site. With the aim to summarize emerging efforts in combating respiratory tract infections by using nanoparticle-mediated pulmonary delivery strategies, this review provides a brief introduction to the bacterial infection-related pulmonary diseases and the biological barriers for effective treatment of recalcitrant respiratory tract infections. This is followed by a summary of recent advances in design of inhalable nanoparticle-based drug delivery systems that overcome the biological barriers and increase drug bioavailability. Finally, challenges for the translation from exploratory laboratory research to clinical application are also discussed and potential solutions proposed.

Bacterial biofilm represents a protected mode of bacterial growth that significantly enhances the resistance to antibiotics. Poly lactic-co-glycolic acid (PLGA)-based nanoparticle delivery systems have been intensively investigated to combat the bacterial biofilms-associated infections. However, some drawbacks associated with current PLGA-based nanoformulations (e.g. the relatively low drug loading capability, premature burst release and/or incapability of on-demand release of cargos at the site of action) restrict the transition from the lab research to the clinical applications. One potent strategy to overcome the above-mentioned limitations is exploiting the unique properties of carbon quantum dots (CQDs) and combining CQDs with the conventional PLGA nanoparticles. In the present study, the CQDs were innovatively incorporated into PLGA nanoparticles by using a microfluidic method. The resulting CQD-PLGA hybrid nanoparticles presented good loading capability of azithromycin (a macrolide antibiotic, AZI) and tobramycin (an aminoglycoside antibiotic, TOB), and stimuli-responsive release of the cargos upon laser irradiation. Consequently, AZI-loaded CQD-PLGA hybrid nanoparticles showed chemo-photothermally synergistic anti-biofilm effects against P. aeruginosa biofilms. Additionally, the CQD-PLGA hybrid nanoparticles demonstrated good biocompatibility with the eukaryotic cells. Overall, the proof-of-concept of CQD-PLGA hybrid nanoparticles may open a new possibility in chemo-photothermal therapy against bacterial biofilms., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Complex nanostructures are increasingly becoming important in the development of novel functional nanomaterials. Nano drug depots, characterized by core-shell structures with core drug reservoirs, are drawing increasing attention because of its potential applications in furnishing drug-sustained release profiles. In the present study, two kinds of nano drug depots, one containing a crystal drug reservoir and the other having a medicated composite drug reservoir, were prepared through modified triaxial electrospinning. Their drug-sustained release performances were compared in terms of initial burst release, middle linear release, and the late tailing off release. Although both depots had a linear morphology, clear core-shell nanostructures and the same cellulose acetate shell layer, they provided considerably different tailing off release performances, and thus different sustained release profiles. The composite-based drug depots showed a smaller tailing off drug amount of 2.2%, a shorter time period of 12 h, and a better zero-order controlled release kinetics in general than the crystal-based drug depots, whose tailing off amount was 9.3% over a time period of 36 h. The mechanism was proposed, which had a close relationship with the state of drug in the core reservoir. The present protocols open a new way for producing medicated structural nanomaterials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Metal-organic frameworks (MOFs) have attracted intensive research interest in the biomedical field because of their unique properties. However, in order to realize the high loading capacity and therapeutic efficacy, it is still urgent to develop a multifunctional MOFs-based nanoplatform., Materials and Methods: Herein, a pH/near-infrared (NIR) dual-responsive drug delivery system based on zeolitic imidazolate framework-8 (ZIF-8) is constructed for synergistic chemo-photothermal therapy and dual-modal magnetic resonance (MR)/photoacoustic (PA) imaging. The doxorubicin hydrochloride (DOX) is embedded into ZIF-8 through one-pot method, and the resultant ZIF-8/DOX is then successively modified with polydopamine, Mn ions and poly(ethylene glycol). The obtained ZIF-8/DMPP is systematically characterized, and both its in vitro and in vivo biological effects are evaluated in detail., Results: The ZIF-8/DMPP possesses a high drug-loading content of 18.9% and displays appropriate size and morphology. The pH-dependent degradation and drug release behavior of prepared ZIF-8/DMPP are confirmed. Importantly, the results demonstrate that the photothermal effect of ZIF-8/DMPP under NIR laser irradiation can significantly accelerate its drug releasing rate, further improving the intracellular drug concentrations. Thereafter, the augmented chemotherapeutic efficiency by photothermal effect against cancer cells is verified both in vitro and in vivo. Besides, the favorable MR and PA imaging capacity of ZIF-8/DMPP is also evidenced on the tumor model., Conclusion: Taken together, the surface engineering of ZIF-8-based nanocarrier in this work offers a promising strategy for the multifunctional MOFs-based drug delivery system., Competing Interests: The authors report no conflicts of interest in this work., (© 2020 Guo et al.)

Respiratory tract mucus represents an important barrier for pulmonary drug delivery. Understanding of mucin-nanoparticle interactions is a prerequisite for rational design of inhalable nanoparticles. In the present study, in order to establish a reliable quartz crystal microbalance with dissipation (QCM-D) approach to reveal the effect of the lung microenvironment on the mucin-nanoparticle interactions, we investigated the intrinsic features of the mucin layers immobilized onto sensors via chemical conjugation or physical adsorption by using atomic force microscopy (AFM) and QCM-D. Our results demonstrated that the covalently-grafted mucin layer responded more sensitively than the physically-adsorbed mucin layer to the local microenvironment shifting from PBS (pH 7.35 and ionic strength 30 mM) to PBS (pH 6.25 and ionic strength 150 mM) and resulted in a softer mucin layer with more hydrophobic areas exposed. Furthermore, using the QCM-D approach with the covalently-grafted mucin layer, we demonstrated the significant influence of the local microenvironment on the interaction of mucin with poly (lactic-co-glycolic acid)-based nanoparticles with different surface hydrophilicity. The present work underlines the QCM-D approach with a covalently-grafted mucin layer as a potent tool to elucidate the potential influence of local microenvironment on mucin-nanoparticle interactions. STATEMENT OF SIGNIFICANCE: Studying interactions between nanoengineered materials and biological systems plays a vital role in development of biomedical applications of nanoengineered materials. In this work, by employing a more biologically relevant, 'free-floating' mucin layer model, we demonstrate the significant impact of the lung microenvironment on the nature and the extent of the interaction between the mucin and the nanoparticles with different surface hydrophilicity. To the best of our knowledge, this is the first work describing the nanoscale properties of immobilized mucin layers and investigating the mucin-nanoparticle interactions with emphasis on the impact of local microenvironment in lungs. Thus, it is expected to have important consequences in rational design of inhalable nanoparticle delivery systems., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier Ltd.)

Drug administration failure has been often witnessed in pediatric due to children's resistance to take medicines with bitter taste. Taste-masking is the key requirement among the scanty drugs available for children. Solid taste-masking systems, such as tablets and capsules, are difficult to swallow for children. Therefore, a liquid taste-masking system based on lyotropic liquid crystalline nanoparticles (LLCNs) was developed in this study. Cefpodoxime proxetil (CFP), a typically bitter drug used as antibiotic in pediatric, was selected as the model drug, and the encapsulation of CFP into the LLCNs was envisaged to improve their taste. Pluronic F127 was added to improve the colloidal stability of CFP-LLCNs. The optimized CFP-LLCNs showed the particle size of 187.29 ± 4.12 nm and the encapsulation efficiency of 85.80%. The mesophase analysis by polarized light microscopy and small angle X-ray scattering confirmed the cubic phase of CFP-LLCNs. It showed a sustained-release profile well fitted to Higuchi model, indicating that diffusion and erosion were both responsible for the CFP release. The taste-masking ability of CFP-LLCNs was confirmed by electronic tongue, compared to CFP and commercial product. The colloidal stability was verified after 3 months storage in room condition (25 ± 2 °C, 70 ± 2%RH). To sum up, the taste-masking and colloidal-stable CFP-LLCNs showed great potential for pediatric oral delivery., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Inhaled antibiotic treatment of cystic fibrosis-related bacterial biofilm infections is challenging because of the pathological environment of the lungs. Here, we present an "environment-adaptive" nanoparticle composed of a solid poly lactic- co -glycolic acid (PLGA) core and a mucus-inert, enzymatically cleavable shell of d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) for the site-specific delivery of antibiotics to bacterial biofilms via aerosol administration. The hybrid nanoparticles with ultrasmall size were self-assembled via a nanoprecipitation process by using a facile microfluidic method. The interactions of the nanoparticles with the biological barriers were comprehensively investigated by using cutting-edge techniques (e.g., quartz crystal microbalance with dissipation monitoring, total internal reflection fluorescence microscopy-based particle tracking, in vitro biofilm model cultured in a flow-chamber system, and quantitative imaging analysis). Our results suggest that the mucus-inert, enzymatically cleavable TPGS shell enables the nanoparticles to penetrate through the mucus, accumulate in the deeper layer of the biofilms, and serve as sustained release depot, thereby improving the killing efficacy of azithromycin (a macrolide antibiotic) against biofilm-forming Pseudomonas aeruginosa . In conclusion, the ultrasmall TPGS-PLGA hybrid nanoparticles represent an efficient delivery system to overcome the multiple barriers and release antibiotics in a sustained manner in the vicinity of the biofilm-forming bacteria.

Hypothesis: The widespread resistance of bacteria to traditional antibiotic treatments has expedited the search for novel therapies against these pathogens. The hypothesis of this work is that two distinctively different polymeric delivery systems, specifically D-α-tocopherol polyethylene glycol 1000 succinate (TPGS)-poly(lactic-co-glycolic acid) (PLGA) nanoparticles and octenyl succinic anhydride-modified low molecular weight hyaluronic acid (OSA-HA) nanogels may be used to substantially improve the properties of azithromycin, allowing its use for effective treatment of Pseudomonas aeruginosa biofilm infections., Experiments: Azithromycin was encapsulated in both delivery systems and the physicochemical properties of the loaded delivery systems, including size, surface charge and drug loading were evaluated. Additionally, particle interaction with a mucin layer, penetration into a bacterial biofilm, prevention of biofilm formation and eradication of pre-formed biofilms, the influence on production of virulence factors and bacterial motility as well as cytotoxicity towards hepatocytes and lung epithelial cells were compared head-to-head., Findings: The TPGS-PLGA nanoparticles noticeably improved the antimicrobial activity and the biofilm prevention activity of azithromycin whereas the OSA-HA nanogels showed reduced mucin interactions together with improved reduction of pre-formed biofilms and maintained the low eukaryotic cell cytotoxicity of azithromycin., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Poly(lactic- co-glycolic acid) (PLGA) microparticles represent a promising formulation approach for providing steady pharmacokinetic/pharmacodynamic profiles of therapeutic drugs for a long period. Understanding and controlling the supramolecular structure of PLGA microparticles at a molecular level is a prerequisite for the rational design of well-controlled, reproducible sustained-release profiles. Herein, we reveal the role of PLGA molecular conformation in particle formation and drug release. The nanoscale network of PLGA microparticles spray-dried using the solvents with distinct polarities was investigated by using NMR and neutron scattering. By employing chemometric method, we further demonstrate the evolution of nanoscale networks in spray-dried PLGA microparticles upon water absorption. Our results indicate that PLGA molecules form more chain entanglements during spray drying when using the solvents with low polarity, where PLGA molecule adopts a more flexible, extended conformation, resulting in the network being more resistant to water absorption in spray-dried PLGA microparticles. This work underlines the role of PLGA molecular conformation in controlling formation and evolution of nanoscale network of spray-dried PLGA microparticles and will have important consequences in achieving customized drug release from the PLGA microparticles.

Nanoparticle (NP) mediated drug delivery into viscous biomatrices, e.g., mucus and bacterial biofilms, is challenging. Lipid shell-enveloped polymeric NPs (Lipid@NPs), composed of a polymeric NP core coated with a lipid shell, represent a promising alternative to the current delivery systems. Here, we describe the facile methods to prepare Lipid@NPs with high integrity of lipid shells and demonstrate the potential of Lipid@NPs in an effective mucus penetration and interaction with cystic fibrosis-related bacterial biofilms. Lipid shell-enveloped polystyrene NPs with high integrity of lipid shells ( cLipid@PSNPs) were prepared by using an electrostatically mediated layer-by-layer approach, where the model polystyrene NPs (PSNPs) were first modified with positively charged poly-l-lysine (PLL) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), followed by subsequent fusion with zwitterionic, PEGylated small unilamellar vesicles (SUVs). The interaction of the PSNPs with SUVs was significantly enhanced by modifying the PSNPs with PLL and DOTAP, which eventually resulted in the formation of cLipid@PSNPs, i.e., Lipid@PLL-PSNPs and Lipid@DOTAP-PSNPs. Improved mucus-penetrating property of cLipid@PSNPs was demonstrated by quartz crystal microbalance with dissipation monitoring measurements. Furthermore, fluorescence resonance energy transfer measurements showed that the interaction of the cLipid@PSNPs with bacterial biofilms was significantly promoted. In conclusion, we prepared cLipid@PSNPs via an electrostatically mediated layer-by-layer approach. Our results suggest that the integrity of the lipid envelopes is crucial for enabling the diffusion of Lipid@PSNPs into the mucus layer and promoting the interaction of Lipid@PSNPs with a bacterial biofilm.

Mucosal administration of drugs and drug delivery systems has gained increasing interest. However, nanoparticles intended to protect and deliver drugs to epithelial surfaces require transport through the surface-lining mucus. Translation from bench to bedside is particularly challenging for mucosal administration since a variety of parameters will influence the specific barrier properties of the mucus including the luminal fluids, the microbiota, the mucus composition and clearance rate, and the condition of the underlying epithelia. Besides, after administration, nanoparticles interact with the mucosal components, forming a biomolecular corona that modulates their behavior and fate after mucosal administration. These interactions are greatly influenced by the nanoparticle properties, and therefore different designs and surface-engineering strategies have been proposed. Overall, it is essential to evaluate these biomolecule-nanoparticle interactions by complementary techniques using complex and relevant mucus barrier matrices., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Pure drug nanoparticles (NPs) represent a promising formulation for improved drug solubility and controlled dissolution velocity. However, limited absorption by the intestinal epithelium remains challenge to their clinical application, and little is known about how these NPs within the cells are transported. To improve cellular uptake and transport of pure nanodrug in cells, here, a lipid covered saquinavir (SQV) pure drug NP (Lipo@nanodrug) was designed by modifying a pure SQV NP (nanodrug) with a phospholipid bilayer. We studied their endocytosis, intracellular trafficking mechanism using Caco-2 cell model. Uptake of Lipo@nanodrug by Caco-2 cells was 1.91-fold greater than that of pure nanodrug via processes involving cell lipid raft. The transcellular transport of Lipo@nanodrug across Caco-2 monolayers was 3.75-fold and 1.92-fold higher than that of coarse crystals and pure nanodrug, respectively. Within cells, Lipo@nanodrug was mainly localized in the endoplasmic reticulum and Golgi apparatus, leading to transcytosis of Lipo@nanodrug across intestinal epithelial cells, whereas pure nanodrug tended to be retained and to dissolve in cell and removed by P-gp-mediated efflux. In rats, the oral bioavailability of the model drug SQV after Lipo@nanodrug administration was 4.29-fold and 1.77-fold greater than after coarse crystal and pure nanodrug administration, respectively. In conclusion, addition of a phospholipid bilayer to pure drug NP increased their cellular uptake and altered their intracellular processing, helping to improve drug transport across intestinal epithelium. To our knowledge, this is the first presentation of the novel phospholipid bilayer covered SQV pure drug NP design, and a mechanistic study on intracellular trafficking in in vitro cell models has been described. The findings provide a new platform for oral delivery of poorly water-soluble drugs., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Medicines based on small interfering RNA (siRNA) are promising for the treatment of a number of lung diseases. However, efficient delivery systems and design of stable dosage forms are required for inhalation therapy, as well as cost-effective methods for manufacturing of the final product. In this study, a 3D-printed micromixer was used for preparation of siRNA-dendrimer nanocomplexes, which were subsequently processed into microparticle-based dry powders for inhalation using spray drying. By applying the disposable micromixer, nanocomplexes were prepared of an average hydrodynamic diameter comparable to that of nanocomplexes prepared by manual mixing, but with narrower size distribution and low batch-to-batch variation. The nanocomplexes were processed into nanoembedded microparticles using different saccharide excipients. Data showed that siRNA integrity and bioactivity are retained after processing, and nanocomplexes could be reconstituted from the dry powders. The amorphous saccharide excipients trehalose and inulin provided better stabilization than crystalline mannitol, and they enabled full reconstitution of the nanocomplexes. In particular, a binary mixture of trehalose and inulin showed optimal stabilization, and enhanced cellular uptake and gene silencing efficiency. This study demonstrates that inexpensive and scalable micromixers can be used to optimize the production of siRNA-dendrimer nanocomplexes, and they can be applied in combination with spray drying for the engineering of dry powder formulations suitable for delivery of siRNA to the therapeutic target site., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In this study, the conjugate of PEG2000-stearic acid (PEG2000-SA) was used to prepare PEGylated solid lipid nanoparticles loading vinorelbine bitartrate (VB-pSLNs) by cold homogenization technique. The particle size and zeta potential of resulted VB-pSLNs ranged 180-250nm and 0-10mV, which were determined using a Zetasizer, respectively. Although the drug entrapment efficiency (EE) slightly decreased after the PEG modification of VB-SLNs, above 60 % EE could be reached. The drug release tests in vitro indicated the faster drug release from VB-pSLNs than that from VB-SLNs without PEG modification. To investigate the cellular uptake of VB-pSLNs, the chemical conjugate of octadecylamine-fluorescein isothiocynate (FITC-ODA) was synthesized, and was used as a fluorescence marker to incorporate into nanoparticles. The results from cellular uptake indicated that the phagocytosis of VB-pSLNs by RAW264.7 cells was inhibited effectively by the PEG modification of SLNs, while the uptake by cancer cells (MCF-7 and A549) could be improved significantly. The assay of anticancer activity in vitro demonstrated that the anticancer activity of VB was significantly enhanced by the encapsulation of SLNs and pSLNs due to the increased cellular internalization of drug. The results suggested that SLNs and pSLNs could be excellent carrier candidates to entrap VB for tumor chemotherapeutics.

A hydrophilic and temperature-induced degradation drug, vinorelbine bitartrate (VB)-loaded solid lipid nanoparticles (SLNs) were prepared by a cold homogenization technique. The physicochemical properties of the SLNs, with various lipid composition, drug content and altered homogenizing times, were investigated. The mean particle size of the SLNs ranged from 150 to 350 nm. The enhancement of lecithin content in lipid matrix resulted in smaller particle of SLNs. The atomic force microscopy (AFM) images displayed that the shape of the SLNs was irregular sphere with smooth surface. The drug entrapment efficiency (EE) could be improved with the increasing of lecithin or oleic acid content in lipid matrix, and reduced with the added amount of drug. The highest EE and drug loading capacity (DL) could reach up to 80 and 6.6%, respectively. The studies of drug release showed that the drug release could last for 48 h, and the rate was delayed by the addition of lecithin or oleic acid in the formulations. The physical stability experiment indicated that the SLNs were stable for 2 months under room temperature. Moreover, the cellular cytotoxicity of VB against MCF-7 cells could be improved by the entrapment of SLNs.