Nanoencapsulated budesonide in self-stratified polyurethane-polyurea nanoparticles is highly effective in inducing human tolerogenic dendritic cells

Favorable Heteroaromatic Thiazole-Based Polyurea Derivatives as Interesting Biologically Active Products

This research sought to synthesize a new set of heteroaromatic thiazole-based polyurea derivatives with sulfur links in the polymers' main chains, which were denoted by the acronyms PU_1-5. Using pyridine as a solvent, a diphenylsulfide-based aminothiazole monomer (M2) was polymerized via solution polycondensation with varied aromatic, aliphatic, and cyclic diisocyanates. Typical characterization methods were used to confirm the structures of the premonomer, monomer, and fully generated polymers. The XRD results revealed that aromatic-based polymers had higher crystallinity than aliphatic and cyclic derivatives. SEM was used to visualize the surfaces of PU₁, PU₄, and PU₅, revealing spongy and porous shapes, shapes resembling wooden planks and sticks, and shapes resembling coral reefs with floral shapes at various magnifications. The polymers demonstrated thermal stability. The numerical results for PDTmax are listed in the following order, ranked from lowest to highest: PU₁ < PU₂ < PU₃ < PU₅ < PU₄. The FDT values for the aliphatic-based derivatives (PU₄ and PU₅) were lower than those for the aromatic-based ones (616, 655, and 665 °C). PU₃ showed the greatest inhibitory impact against the bacteria and fungi under investigation. In addition, PU₄ and PU₅ demonstrated antifungal activities that, in contrast with the other products, were on the lower end of the spectrum. Furthermore, the intended polymers were also tested for the presence of the proteins 1KNZ, 1JIJ, and 1IYL, which are frequently utilized as model organisms for E. coli (Gram-negative bacteria), S. aureus (Gram-positive bacteria), and C. albicans (fungal pathogens). This study's findings are consistent with the outcomes of the subjective screening.

Novel Tumor-Targeted Self-Nanostructured and Compartmentalized Water-in-Oil-in-Water Polyurethane-Polyurea Nanocapsules for Cancer Theragnosis

Encapsulation of water-soluble bioactive compounds for enabling specific accumulation in tumor locations, while avoiding premature clearance and/or degradation in the bloodstream, is one of the main hallmarks in nanomedicine, especially that of NIR fluorescent probes for cancer theragnosis. The herein reported technology furnishes water-dispersible double-walled polyurethane-polyurea hybrid nanocapsules (NCs) loaded with indocyanine green (ICG-NCs), using a versatile and highly efficient one-pot and industrially scalable synthetic process based on the use of two different prepolymers to set up the NCs walls. Flow cytometry and confocal microscopy confirmed that both ICG-loaded NCs internalized in monocyte-derived dendritic cells (moDCs). The in vivo analysis of xenograft A375 mouse melanoma model revealed that amphoteric functionalization of NCs' surface promotes the selective accumulation of ICG-NCs in tumor tissues, making them promising agents for a less-invasive theragnosis of cancer.

Redox-responsive polyurethane-polyurea nanoparticles targeting to aortic endothelium and atherosclerosis

Aortic endothelial cell dysfunction is an early trigger of atherosclerosis, the major cause of the cardiovascular disease (CVD). Nanomedicines targeting vascular endothelium and lesions hold great promise as therapeutic solutions to vascular disorders. This study investigates the vascular delivery efficacy of polyurethane-polyurea nanocapsules (Puua-NCs) with pH-synchronized shell cationization and redox-triggered release. Fluorescent lipophilic dye DiI was encapsulated into Puua-NCs of variable sizes and concentrations. In vitro cellular uptake studies with human aortic endothelial cells showed that these Puua-NCs were taken up by cells in a dose-dependent manner. In apolipoprotein E-deficient mice fed a Western diet, a model of atherosclerosis, circulating Puua-NCs were stable and accumulated in aortic endothelium and lesions within 24 hours after intravenous administration. Treatment with thiol-reducing and oxidizing reagents disrupted the disulfide bonds on the surface of internalized NCs, triggering disassembly and intracellular cargo release. Ultimately, Puua-NCs are a potential redox-controllable cardiovascular drug delivery system.

Structure-Dependent Nontraditional Intrinsic Fluorescence of Aliphatic Hyperbranched Polyureas

The nontraditional intrinsic fluorescence (NTIF) of polymers containing heteroatoms has gained considerable attention due to its promising applications in label-free bioimaging. Aliphatic hyperbranched polyureas (aBPUs), which have recently shown great promise in the field of nanomedicine, bear controllable urea groups distributed on the branch points and thus are potential candidate luminogens. However, their NTIF properties and how their structures influence the NTIF properties have not been illustrated yet. Here, we addressed these issues by synthesizing a series of aBPUs with different degrees of branching (DBs) or different modifications. aBPUs exhibited an obvious NTIF phenomenon and with the increase of DBs, the NTIF enhanced as well. Chemical modifications either at the branching ends or in the interior of aBPUs could affect the NTIF performances, which were highly dependent on the types of modification. Disruption of the intra-/intermolecular hydrogen-bonding interactions decreased the NTIF. In addition, poly(ethylene glycol) (PEG)-modified aBPUs could self-assemble into nanospheres, and the formation of nanoassembly led to 89% enhancement on NTIF compared with the homogeneous solution of aBPUs-PEG in dimethylformamide (DMF). Finally, aBPUs-PEG nanoassembly demonstrated a capability in realizing label-free material imaging in vitro. These results shed light on the rational design of the polymer structures to achieve desired fluorescence with unconventional luminophores.

Improving Photodynamic Therapy Anticancer Activity of a Mitochondria-Targeted Coumarin Photosensitizer Using a Polyurethane-Polyurea Hybrid Nanocarrier

Integration of photosensitizers (PSs) within nanoscale delivery systems offers great potential for overcoming some of the “Achiles’ heels” of photodynamic therapy (PDT). Herein, we have encapsulated a mitochondria-targeted coumarin PS into amphoteric polyurethane–polyurea hybrid nanocapsules (NCs) with the aim of developing novel nanoPDT agents. The synthesis of coumarin-loaded NCs involved the nanoemulsification of a suitable prepolymer in the presence of a PS without needing external surfactants, and the resulting small nanoparticles showed improved photostability compared with the free compound. Nanoencapsulation reduced dark cytotoxicity of the coumarin PS and significantly improved in vitro photoactivity with red light toward cancer cells, which resulted in higher phototherapeutic indexes compared to free PS. Importantly, this nanoformulation impaired tumoral growth of clinically relevant three-dimensional multicellular tumor spheroids. Mitochondrial photodamage along with reactive oxygen species (ROS) photogeneration was found to trigger autophagy and apoptotic cell death of cancer cells.

Polyurethane-polyurea hybrid nanocapsules as efficient delivery systems of anticancer Ir(III) metallodrugs

Cyclometalated Ir(III) complexes hold great promise as an alternative to platinum metallodrugs for therapy and diagnosis of cancer. However, low aqueous solubility and poor cell membrane permeability difficult in vivo...

Multi-Smart and Scalable Bioligands-Free Nanomedical Platform for Intratumorally Targeted Tambjamine Delivery, a Difficult to Administrate Highly Cytotoxic Drug

Cancer is one of the leading causes of mortality worldwide due, in part, to limited success of some current therapeutic approaches. The clinical potential of many promising drugs is restricted by their systemic toxicity and lack of selectivity towards cancer cells, leading to insufficient drug concentration at the tumor site. To overcome these hurdles, we developed a novel drug delivery system based on polyurea/polyurethane nanocapsules (NCs) showing pH-synchronized amphoteric properties that facilitate their accumulation and selectivity into acidic tissues, such as tumor microenvironment. We have demonstrated that the anticancer drug used in this study, a hydrophobic anionophore named T21, increases its cytotoxic activity in acidic conditions when nanoencapsulated, which correlates with a more efficient cellular internalization. A biodistribution assay performed in mice has shown that the NCs are able to reach the tumor and the observed systemic toxicity of the free drug is significantly reduced in vivo when nanoencapsulated. Additionally, T21 antitumor activity is preserved, accompanied by tumor mass reduction compared to control mice. Altogether, this work shows these NCs as a potential drug delivery system able to reach the tumor microenvironment, reducing the undesired systemic toxic effects. Moreover, these nanosystems are prepared under scalable methodologies and straightforward process, and provide tumor selectivity through a smart mechanism independent of targeting ligands.

Pretilachlor Releasable Polyurea Microcapsules Suspension Optimization and Its Paddy Field Weeding Investigation

In this study, pretilachlor was encapsulated into polyurea microcapsules prepared by water-initiated polymerization of polyaryl polymethylene isocyanate and eventually made into pretilachlor microcapsules suspension (PMS). We used response surface methodology (RSM) combined with the Box–Behnken design (BBD) model to optimize the formulation of PMS. The encapsulation efficiency (EE) of PMS was investigated with respect to three independent variables including wall material dosage (X₁), emulsifier dosage (X₂), and polymerization stirring speed (X₃). The results showed that the regression equation model had a satisfactory accuracy in predicting the EE of PMS. To achieve an optimal condition for PMS preparation, the dose of wall material was set to 5%, the dose of emulsifier was set to 3.5% and the polymerization stirring speed was set to 200 rpm. The EE of PMS was up to 95.68% under the optimized condition, and the spherical shape with smooth surface morphology was observed. PMS was also proven to have delayed release capability and in vivo herbicidal activity against barnyard grass [Echinochloa crusgalli (L.) Beauv.] with an LC₅₀ value of 274 mg/L. Furthermore, PMS had efficient weed management compared to commercially available 30% pretilachlor emulsifier (PE), showing a promising potential application for weeding paddy fields.

PEGylated Polyurea Bearing Hindered Urea Bond for Drug Delivery

In recent years, polyureas with dynamic hindered urea bonds (HUBs), a class of promising biomedical polymers, have attracted wide attention as a result of their controlled hydrolytic properties. The effect of the chemical structures on the properties of polyureas and their assemblies has rarely been reported. In this study, four kinds of polyureas with different chemical groups have been synthesized, and the polyureas from cyclohexyl diisocyanate and tert-butyl diamine showed the fastest hydrolytic rate. The amphiphilic polyurea composed of hydrophobic cyclohexyl-tert-butyl polyurea and hydrophilic poly(ethylene glycol) (PEG) was synthesized for the controlled delivery of the antitumor drug paclitaxel (PTX). The PTX-loaded PEGylated polyurea micelle more effectively entered into the murine breast cancer 4T1 cells and inhibited the corresponding tumor growth in vitro and in vivo. Therefore, the PEGylated polyurea with adjustable degradation might be a promising polymer matrix for drug delivery.

Improved pharmacokinetic profile of lipophilic anti-cancer drugs using ανβ3-targeted polyurethane-polyurea nanoparticles

Glutathione degradable polyurethane-polyurea nanoparticles (PUUa NP) with a disulfide-rich multiwalled structure and a cyclic RGD peptide as a targeting moiety were synthesized, incorporating a very lipophilic chemotherapeutic drug named Plitidepsin. In vitro studies indicated that encapsulated drug maintained and even improved its cytotoxic activity while in vivo toxicity studies revealed that the maximum tolerated dose (MTD) of Plitidepsin could be increased three-fold after encapsulation. We also found that pharmacokinetic parameters such as maximum concentration (Cmax), area under the curve (AUC) and plasma half-life were significantly improved for Plitidepsin loaded in PUUa NP. Moreover, biodistribution assays in mice showed that RGD-decorated PUUa NP accumulate less in spleen and liver than non-targeted conjugates, suggesting that RGD-decorated nanoparticles avoid sequestration by macrophages from the reticuloendothelial system. Overall, our results indicate that polyurethane-polyurea nanoparticles represent a very valuable nanoplatform for the delivery of lipophilic drugs by improving their toxicological, pharmacokinetic and whole-body biodistribution profiles.