Manipulation of Macrophage Uptake by Controlling the Aspect Ratio of Graft Copolymer Micelles.

Nanostructures of drug carriers play a crucial role in nanomedicine due to their ability to influence drug delivery. There is yet no clear consensus regarding the optimal size and shape (e.g., aspect ratio) of nanoparticles for minimizing macrophage uptake, given the difficulties in controlling the shape and size of nanoparticles while maintaining identical surface properties. Here, we employed graft copolymer self-assembly to prepare polymer micelles with aspect ratios ranging from 1.0 (spherical) to 10.8 (cylindrical) and closely matched interfacial properties. Notably, our findings emphasize that cylindrical micelles with an aspect ratio of 2.4 are the least susceptible to macrophage uptake compared with both their longer counterparts and spherical micelles. This reduced uptake of the short cylindrical micelles results in a 3.3-fold increase in blood circulation time compared with their spherical counterparts. Controlling the aspect ratio of nanoparticles is crucial for improving drug delivery efficacy through better nanoparticle design.

Mannosylated Systems for Targeted Delivery of Antibacterial Drugs to Activated Macrophages.

Macrophages are a promising target for drug delivery to influence macrophage-associated processes in the body, namely due to the presence of resistant microorganisms in macrophages. In this work, a series of mannosylated carriers based on mannan, polyethylenimine (PEI) and cyclodextrin (CD) was synthesized. The molecular architecture was studied using FTIR and 1H NMR spectroscopy. The particle size, from small 10-50 nm to large 500 nm, depending on the type of carrier, is potentially applicable for the creation of various medicinal forms: intravenous, oral and inhalation. Non-specific capture by cells with a simultaneous increase in selectivity to CD206+ macrophages was achieved. ConA was used as a model mannose receptor, binding galactosylated (CD206 non-specific) carriers with constants of the order of 104 M-1 and mannosylated conjugates of 106-107 M-1. The results of such primary "ConA-screening" of ligands are in a good agreement in terms of the comparative effectiveness of the interaction of ligands with the CD206+ macrophages: non-specific (up to 10%) absorption of highly charged and small particles; weakly specific uptake of galactosylated polymers (up to 50%); and high affine capture (more than 70-80%) of the ligands with grafted trimannoside was demonstrated using the cytometry method. Double and multi-complexes of antibacterials (moxifloxacin with its adjuvants from the class of terpenoids) were proposed as enhanced forms against resistant pathogens. In vivo pharmacokinetic experiments have shown that polymeric carriers significantly improve the efficiency of the antibiotic: the half-life of moxifloxacin is increased by 2-3 times in conjugate-loaded forms, bio-distribution to the lungs in the first hours after administration of the drug is noticeably greater, and, after 4 h of observation, free moxifloxacin was practically removed from the lungs of rats. Although, in polymer systems, its content is significant-1.2 µg/g. Moreover, the importance of the covalent crosslinking carrier with mannose label was demonstrated. Thus, this paper describes experimental, scientifically based methods of targeted drug delivery to macrophages to create enhanced medicinal forms.

Activity of Chitosan and Its Derivatives against Leishmania major and Leishmania mexicana In Vitro.

There is an urgent need for safe, efficacious, affordable, and field-adapted drugs for the treatment of cutaneous leishmaniasis, which newly affects around 1.5 million people worldwide annually. Chitosan, a biodegradable cationic polysaccharide, has previously been reported to have antimicrobial, antileishmanial, and immunostimulatory activities. We investigated the in vitro activity of chitosan and several of its derivatives and showed that the pH of the culture medium plays a critical role in antileishmanial activity of chitosan against both extracellular promastigotes and intracellular amastigotes of Leishmania major and Leishmania mexicana Chitosan and its derivatives were approximately 7 to 20 times more active at pH 6.5 than at pH 7.5, with high-molecular-weight chitosan being the most potent. High-molecular-weight chitosan stimulated the production of nitric oxide and reactive oxygen species by uninfected and Leishmania-infected macrophages in a time- and dose-dependent manner at pH 6.5. Despite the in vitro activation of bone marrow macrophages by chitosan to produce nitric oxide and reactive oxygen species, we showed that the antileishmanial activity of chitosan was not mediated by these metabolites. Finally, we showed that rhodamine-labeled chitosan is taken up by pinocytosis and accumulates in the parasitophorous vacuole of Leishmania-infected macrophages.

Nanoparticle Drug Delivery Can Reduce the Hepatotoxicity of Therapeutic Cargo.

Hepatotoxicity is a key concern in the clinical translation of nanotherapeutics because preclinical studies have consistently shown that nanotherapeutics accumulates extensively in the liver. However, clinical-stage nanotherapeutics have not shown increased hepatotoxicity. Factors that can contribute to the hepatotoxicity of nanotherapeutics beyond the intrinsic hepatotoxicity of nanoparticles (NPs) are poorly understood. Because of this knowledge gap, clinical translation efforts have avoided hepatotoxic molecules. By examining the hepatotoxicity of nanoformulations of known hepatotoxic compounds, it is demonstrated that nanotherapeutics are associated with lower hepatotoxicity than their small-molecule counterparts. It is also found that the reduced hepatotoxicity is related to the uptake of nanotherapeutics by macrophages in the liver. These findings can facilitate further development and clinical translation of nanotherapeutics.

Polysaccharide Submicrocarrier for Improved Pulmonary Delivery of Poorly Soluble Anti-infective Ciprofloxacin: Preparation, Characterization, and Influence of Size on Cellular Uptake.

The majority of the currently used and developed anti-infectives are poorly water-soluble molecules. The poor solubility might lead to limited bioavailability and pharmacological action of the drug. Novel pharmaceutical materials have thus been designed to solve those problems and improve drug delivery. In this study, we propose a facile method to produce submicrocarriers (sMCs) by electrostatic gelation of anionic ß-cyclodextrin (aß-CD) and chitosan. The average hydrodynamic size ranged from 400 to 900 nm by carefully adjusting polymer concentrations and N/C ratio. The distinct host-guest reaction of cyclodextrin derivative is considered as a good approach to enhance solubility, and prevent drug recrystallization, and thus was used to develop sMC to improve the controlled release profile of a poorly soluble and clinically relevant anti-infective ciprofloxacin. The optimal molar ratio of ciprofloxacin to aß-CD was found to be 1:1, which helped maximize encapsulation efficiency (∼90%) and loading capacity (∼9%) of ciprofloxacin loaded sMCs. Furthermore, to recommend the future application of the developed sMCs, the dependence of cell uptake on sMCs size (500, 700, and 900 nm) was investigated in vitro on dTHP-1 by both flow cytometry and confocal microscopy. The results demonstrate that, regardless of their size, an only comparatively small fraction of the sMCs were taken up by the macrophage-like cells, while most of the carriers were merely adsorbed to the cell surface after 2 h incubation. After continuing the incubation to reach 24 h, the majority of the sMCs were found intracellularly. However, the sMCs had been designed to release sufficient amount of drug within 24 h, and the subsequent phagocytosis of the carrier may be considered as an efficient pathway for its safe degradation and elimination. In summary, the developed sMC is a suitable system with promising perspectives recommended for pulmonary extracellular infection therapeutics.

In vivo tumor targeting and biodistribution evaluation of paramagnetic solid lipid nanoparticles for magnetic resonance imaging.

The current study was performed to evaluate the in vivo efficiency of a new nano-sized contrast agent called paramagnetic Solid Lipid Nanoparticles, pSLNs, having promising relaxivity properties for Magnetic Resonance Imaging application. Good stability and stealth properties toward macrophage uptake have been demonstrated. An in vivo MRI study resulted in an improved signal enhancement in the tumor tissue particularly when folate as targeting ligand was used to decorate the nanoparticles surface. Afterward, the biodistribution of pSLNs in several organs was investigated. The accumulation of pSLNs in kidneys, femoral bones, spleen and brain was quite low while high tropism of pSLNs was found for the liver. In this regard, approaches to improve the rate of the hepatic clearance have been proposed.

Biomimetic-Membrane-Protected Plasmonic Nanostructures as Dual-Modality Contrast Agents for Correlated Surface-Enhanced Raman Scattering and Photoacoustic Detection of Hidden Tumor Lesions.

Optical imaging and spectroscopic modalities are of considerable current interest for in vivo cancer detection and image-guided surgery, but the turbid or scattering nature of biomedical tissues has severely limited their abilities to detect buried or occluded tumor lesions. Here we report the development of a dual-modality plasmonic nanostructure based on colloidal gold nanostars (AuNSs) for simultaneous surface-enhanced Raman scattering (SERS) and photoacoustic (PA) detection of tumor phantoms embedded (hidden) in ex vivo animal tissues. By using red blood cell membranes as a naturally derived biomimetic coating, we show that this class of dual-modality contrast agents can provide both Raman spectroscopic and PA signals for the detection and differentiation of hidden solid tumors with greatly improved depths of tissue penetration. Compared to previous polymer-coated AuNSs, the biomimetic coatings are also able to minimize protein adsorption and cellular uptake when exposed to human plasma without compromising their SERS or PA signals. We further show that tumor-targeting peptides (such as cyclic RGD) can be noncovalently inserted for targeting the ανß3-integrin receptors expressed on metastatic cancer cells and tracked via both SERS and PA imaging (PAI). Finally, we demonstrate image-guided resections of tumor-mimicking phantoms comprising metastatic tumor cells buried under layers of skin and fat tissues (6 mm in thickness). Specifically, PAI was used to determine the precise tumor location, while SERS spectroscopic signals were used for tumor identification and differentiation. This work opens the possibility of using these biomimetic dual-modality nanoparticles with superior signal and biological stability for intraoperative cancer detection and resection.

Zwitterionic Inhaler with Synergistic Therapeutics for Reprogramming of M2 Macrophage to Pro-Inflammatory Phenotype.

Myriad lung diseases are life threatening and macrophages play a key role in both physiological and pathological processes. Macrophages have each pro-/anti-inflammatory phenotype, and each lung disease can be aggravated by over-polarized macrophage. Therefore, development of a method capable of mediating the macrophage phenotype is one of the solutions for lung disease treatment. For mediating the phenotype of macrophages, the pulmonary delivery system (PDS) is widely used due to its advantages, such as high efficiency and accessibility of the lungs. However, it has a low drug delivery efficiency ironically because of the perfect lung defense system consisting of the mucus layer and airway macrophages. In this study, zwitterion-functionalized poly(lactide-co-glycolide) (PLGA) inhalable microparticles (ZwPG) are synthesized to increase the efficiency of the PDS. The thin layer of zwitterions formed on PLGA surface has high nebulizing stability and show high anti-mucus adhesion and evasion of macrophages. As a reprogramming agent for macrophages, ZwPG containing dexamethasone (Dex) and pirfenidone (Pir) are treated to over-polarized M2 macrophages. As a result, a synergistic effect of Dex/Pir induces reprogramming of M2 macrophage to pro-inflammatory phenotypes.

Comparative analysis of PEG-liposomes and RBCs-derived nanovesicles for anti-tumor therapy.

Lipid-based vesicular nanoparticles, for instance liposomes, conjugated with polyethylene glycol (PEG) have proven to be the closest to an ideal drug delivery vehicle, making way for several PEG-liposomes based nanomedicines in market. However, the synthetic nature of the nanomaterial poses a threat to stimulate immune system. Alternatively, nanovesicles derived from mammalian cells, such as RBCs, have gained interests as they may not elicit much immune response due to the presence of host specific self-recognition markers on their surface. While several reports demonstrating the superior efficacy of these naturally derived vesicles have come out in the last few years, a comparison with clinically established liposomes is still missing. Thus, we conducted an in-vitro and in-vivo comparative studies between PEG-Liposomes and nanovesicles (NVEs) derived from red blood cell (RBC) membrane with an aim to establish a biocompatible nanocarrier for efficient delivery of chemotherapeutic drugs and photothermal agents.

Designing, Optimization and Characterization of Trifluralin Transfersomal Gel to Passively Target Cutaneous Leishmaniasis.

Herein, Trifluralin (TFL) laden transfersomes (TFS) were investigated against Cutaneous Leishmaniasis (CL), via localized and targeted dermal delivery of TFL. Designed TFL-TFS were optimized utilizing 23 full factorial design on the basis of desired response factors including Particle size (P.S), Polydispersity index (PDI), TFL entrapment (%EE) and deformability index (DI). Optimized formulation was found to display P.S of 140.3 ± 2.3, PDI of 0.006 ± 0.002, %EE of 86 ± 0.5 and 43.5 ± 1.0 DI. Results of TEM and XRD analysis have shown intact spherical structure of TFL-TFS and alteration in TFL crystallinity, respectively. Moreover, the optimized TFL-TFS were loaded in Carbopol-940 gel to attain protracted skin retention. TFL-TFS were found to exhibit sustain TFL release profile for up to 24 h. Ameliorated skin permeation of TFL-TFS, even in absence of permeation enhancers, has shown its suitability for cutaneous application. Macrophage uptake assay demonstrated higher intracellular penetration, evidenced by intense reddish fluorescence of rhodamine loaded TFS in comparison to rhodamine-solution. In vitro anti-leishmanial assessment was showing 2.86-folds and 3.07-folds decrement in IC50-value of TFL-TFS against L. tropica KWH23 amastigotes and promastigotes, respectively. Percent inhibition assay against intra-macrophage amastigotes demonstrated that 90.87% amastigotes were assassinated at 50 µg/ml concentration of TFL-TFS, in comparison to the plain TFL-solution, exhibiting 54% parasitic killing.