Design attributes of long-circulating polymeric drug delivery vehicles

Cyclic RGD modified dextran-quercetin polymer micelles for targeted therapy of breast cancer

Quercetin is a natural flavonoid found in many plants which has various pharmacological activities including antitumor effect. However, the poor water solubility and bioavailability limit the potential benefits of quercetin for patients. Thus, modifying quercetin structure and developing actively targeted drug delivery systems are extremely important for tumor precision therapy. Herein, polymer-drug conjugates dextran-quercetin (D-Q) and cRGD-dextran (R-D) were synthesized by grafting quercetin and polypeptide cRGDfk (Arg-Gly-Asp-(D-Phe)-Lys) to dextran. Then cRGD-modified dextran-quercetin polymer micelles (R-D-Q) were constructed by self-assembling of D-Q and R-D. R-D-Q micelles possessed appropriate particle size (133.4 nm), nearly neutral potential (8.14 mV) and excellent drug-loading efficiency (13.1 %) and achieved higher cytotoxicity, apoptosis induction and penetration to human breast cancer MCF-7 cells than the micelles unmodified with cRGD, which were ascribed to cRGD-integrin mediated transcytosis. R-D-Q micelles effectively suppressed tumor growth in tumor-bearing mice by delivering more quercetin throughout the tumor tissue. And R-D-Q micelles could promote the apoptosis of tumor cells by activating p38 and JNK signal pathways and suppressing ERK signal pathway. In addition, R-D-Q micelles had no damage to normal tissues of mice at therapeutic dose. These results indicate promising prospects for R-D-Q micelles as an effective drug delivery system against tumor.

Recent advances in the development of poly(ester amide)s-based carriers for drug delivery

Biodegradable and biocompatible biomaterials have several important applications in drug delivery. The biomaterial family known as poly(ester amide)s (PEAs) has garnered considerable interest because it exhibits the benefits of both polyester and polyamide, as well as production from readily available raw ingredients and sophisticated synthesis techniques. Specifically, α-amino acid-based PEAs (AA-PEAs) are promising carriers because of their structural flexibility, biocompatibility, and biodegradability. Herein, we summarize the latest applications of PEAs in drug delivery systems, including antitumor, gene therapy, and protein drugs, and discuss the prospects of drug delivery based on PEAs, which provides a reference for designing safe and efficient drug delivery carriers.

Bioinspired zwitterionic triblock copolymers designed for colloidal drug delivery: 2 - Biological evaluation

In this work, poly(lactide) nanoparticles were equipped with a bioinspired coating layer based on poly[2-(methacryloyloxy)ethyl phosphorylcholine] and then evaluated when administered to the lungs and after intravenous injection. Compared to the plain counterparts, the chosen zwitterionic polymer shell prevented the coated colloidal formulation from aggregation and conditioned it for lower cytotoxicity, protein adsorption, complement activation and phagocytic cell uptake. Consequently, no interference with the biophysical function of the lung surfactant system could be detected accompanied by negligible protein and cell influx into the bronchoalveolar space after intratracheal administration. When injected into the central compartment, the coated formulation showed a prolonged circulation half-life and a delayed biodistribution to the liver. Taken together, colloidal drug delivery vehicles would clearly benefit from the investigated poly[2-(methacryloyloxy)ethyl phosphorylcholine]-based polymer coatings.

The interplay between PEGylated nanoparticles and blood immune system

During the last two decades, an increasing number of reports have pointed out that the immunogenicity of polyethylene glycol (PEG) may trigger accelerated blood clearance (ABC) and hypersensitivity reaction (HSR) to PEGylated nanoparticles, which could make PEG modification counterproductive. These phenomena would be detrimental to the efficacy of the load and even life-threatening to patients. Consequently, further elucidation of the interplay between PEGylated nanoparticles and the blood immune system will be beneficial to developing and applying related formulations. Many groups have worked to unveil the relevance of structural factors, dosing schedule, and other factors to the ABC phenomenon and hypersensitivity reaction. Interestingly, the results of some reports seem to be difficult to interpret or contradict with other reports. In this review, we summarize the physiological mechanisms of PEG-specific immune response. Moreover, we speculate on the potential relationship between the induction phase and the effectuation phase to explain the divergent results in published reports. In addition, the role of nanoparticle-associated factors is discussed based on the classification of the action phase. This review may help researchers to develop PEGylated nanoparticles to avoid unfavorable immune responses based on the underlying mechanism.

(Bio)degradable and Biocompatible Nano-Objects from Polymerization-Induced and Crystallization-Driven Self-Assembly

Polymerization-induced self-assembly (PISA) and crystallization-driven self-assembly (CDSA) techniques have emerged as powerful approaches to produce a broad range of advanced synthetic nano-objects with high potential in biomedical applications. PISA produces nano-objects of different morphologies (e.g., spheres, vesicles and worms), with high solids content (∼10-50 wt %) and without additional surfactant. CDSA can finely control the self-assembly of block copolymers and readily forms nonspherical crystalline nano-objects and more complex, hierarchical assemblies, with spatial and dimensional control over particle length or surface area, which is typically difficult to achieve by PISA. Considering the importance of these two assembly techniques in the current scientific landscape of block copolymer self-assembly and the craze for their use in the biomedical field, this review will focus on the advances in PISA and CDSA to produce nano-objects suitable for biomedical applications in terms of (bio)degradability and biocompatibility. This review will therefore discuss these two aspects in order to guide the future design of block copolymer nanoparticles for future translation toward clinical applications.

Microfluidic Roadmap for Translational Nanotheranostics

Nanotheranostic materials (NTMs) shed light on the mechanisms responsible for complex diseases such as cancer because they enable making a diagnosis, monitoring the disease progression, and applying a targeted therapy simultaneously. However, several issues such as the reproducibility and mass production of NTMs hamper their application for clinical practice. To address these issues and facilitate the clinical application of NTMs, microfluidic systems have been increasingly used. This perspective provides a glimpse into the current state-of-art of NTM research, emphasizing the methods currently employed at each development stage of NTMs and the related open problems. This work reviews microfluidic technologies used to develop NTMs, ranging from the fabrication and testing of a single NTM up to their manufacturing on a large scale. Ultimately, a step-by-step vision on the future development of NTMs for clinical practice enabled by microfluidics techniques is provided.

Anti-platelet Drug-loaded Targeted Technologies for the Effective Treatment of Atherothrombosis

Atherothrombosis results from direct interaction between atherosclerotic plaque and arterial thrombosis and is the most common type of cardiovascular disease. As a long term progressive disease, atherosclerosis frequently results in an acute atherothrombotic event through plaque rupture and platelet-rich thrombus formation. The pathophysiology of atherothrombosis involves cholesterol accumulation endothelial dysfunction, dyslipidemia, immuno-inflammatory, and apoptotic aspects. Platelet activation and aggregation is the major cause for stroke because of its roles, including thrombus, contributing to atherosclerotic plaque, and sealing off the bleeding vessel. Platelet aggregates are associated with arterial blood pressure and cardiovascular ischemic events. Under normal physiological conditions, when a blood vessel is damaged, the task of platelets within the circulation is to arrest the blood loss. Antiplatelet inhibits platelet function, thereby decreasing thrombus formation with complementary modes of action to prevent atherothrombosis. In the present scientific scenario, researchers throughout the world are focusing on the development of novel drug delivery systems to enhance patient's compliance. Immediate responding pharmaceutical formulations become an emerging trend in the pharmaceutical industries with better patient compliance. The proposed review provides details related to the molecular pathogenesis of atherothrombosis and recent novel formulation approaches to treat atherothrombosis with particular emphasis on commercial formulation and upcoming technologies.

Novel Phospholipid-Based Labrasol Nanomicelles Loaded Flavonoids for Oral Delivery with Enhanced Penetration and Anti-Brain Tumor Efficiency

BACKGROUND

Owing to the rich anticancer properties of flavonoids, there is a need for their incorporation into drug delivery vehicles like nanomicelles for safe delivery of the drug into the brain tumor microenvironment.

OBJECTIVE

This study, therefore, aimed to prepare the phospholipid-based Labrasol/Pluronic F68 modified nano micelles loaded with flavonoids (Nano-flavonoids) for the delivery of the drug to the target brain tumor.

METHODS

Myricetin, quercetin and fisetin were selected as the initial drugs to evaluate the biodistribution and acute toxicity of the drug delivery vehicles in rats with implanted C6 glioma tumors after oral administration, while the uptake, retention, release in human intestinal Caco-2 cells and the effect on the brain endothelial barrier were investigated in Human Brain Microvascular Endothelial Cells (HBMECs).

RESULTS

The results demonstrated that nano-flavonoids loaded with myricetin showed more evenly distributed targeting tissues and enhanced anti-tumor efficiency in vivo without significant cytotoxicity to Caco-2 cells and alteration in the Trans Epithelial Electric Resistance (TEER). There was no pathological evidence of renal, hepatic or other organs dysfunction after the administration of nanoflavonoids, which showed no significant influence on cytotoxicity to Caco-2 cells.

CONCLUSION

In conclusion, Labrasol/F68-NMs loaded with MYR and quercetin could enhance antiglioma effect in vitro and in vivo, which may be better tools for medical therapy, while the pharmacokinetics and pharmacodynamics of nano-flavonoids may ensure optimal therapeutic benefits.

Red blood cell-hitchhiking chitosan nanoparticles for prolonged blood circulation time of vitamin K1

Nanocarriers have been extensively applied for intravascular drug delivery. However, rapid clearance from circulation by mononuclear phagocyte system has limited their applications. Erythrocytes carriers are potential solutions to overcome the limitations of nanocarriers and considered to be ideal natural carriers for drug delivery because of their unique properties. The purpose of this work is to combine nanocarriers with erythrocytes carriers for sustained release and prolonged circulation time of vitamin K₁. Chitosan nanoparticles loading VK₁ (VK-CSNPs) were prepared using ionotropic gelation method, which was optimized using box-behnken design and response surface methodology. VK-CSNPs adsorbed onto red blood cells (RBC-VK-CSNPs) rapidly via electrostatic interactions. The exposure of phosphatidylserine, osmotic fragility and turbulence fragility of RBC loading nanoparticles were investigated to study the toxicity of nanoparticles to erythrocytes. In vivo pharmacokinetic study indicated that C_max, AUC and MRT of RBC-VK-CSNPs group were remarkably higher than that of VK-CSNPs group. Flow cytometry showed VK-CSNPs steadily retained on the surface of RBC for a long time without affecting the circulation profiles of RBC themselves. The nanoparticles carried on RBC released drug, desorbed and were eliminated in vivo. Therefore, the circulation time of RBC-hitchhiking chitosan nanoparticles was greatly prolonged compared with nanoparticles alone. RBC-hitchhiking could be a valuable hybrid strategy for prolonging the in vivo life of nanocarriers.

Improved pharmacokinetic and biodistribution of 5-fluorouracil loaded biomimetic nanoerythrocytes decorated nanocarriers for liver cancer treatment

Nanoerythrocytes membrane (NEs) has recently been used to improve pharmacokinetics and biodistribution for successful drug therapy. NEs intended to enhance the drug targeting due to immune evasion and long circulation. In this work, NEs could serve as efficient 5- fluorouracil (5-FU) carriers to target liver cells. NEs decorated 5-FU-loaded chitosan coated-poly (lactide-co-glycolic acid) nanoparticles (5-FU-C-NPs-NEs), chitosomes (5-FU-C-LPs-NEs) and 5-FU-NEs were prepared by hypotonic lysis and extrusion procedures. Moreover, 5-FU loaded-chitosan coated 5-FU-NPs (5-FU-C-NPs) and chitosomes (5-FU-C-LPs) for the compared issues were prepared. They were characterized in terms of particle size, encapsulation efficiency (EE), membrane protein content, phosphatidylserine exposure, surface morphology, and in vitro release profiles. Also, their cytotoxic efficacy was determined. Furthermore, pharmacokinetics and biodistribution studies were investigated for optimized formulation. The results revealed that 5-FU-C-NPs-NEs have narrow particle size distribution, desirable EE%, and retained the erythrocyte membrane properties as confirmed by polyacrylamide gel electrophoresis (SDS-PAGE). Additionally, it displayed a sustained release profile up to 72 h of 5-FU-C-NPs-NEs compared to other formulations. In comparison to 5-FU solution and 5-FU-C-NPs, 5-FU-C-NPs-NEs extended the drug release time in vivo with highly uptake by the liver. These results suggest that the 5-FU-C-NPs-NEs could be used to deliver 5-FU and enhance its targetability to liver cancer.

Periphery-confined particulate systems for the management of neurodegenerative diseases and toxicity: Avoiding the blood-brain-barrier challenge

The blood-brain barrier prevents passage of large and hydrophilic molecules, undermining efforts to deliver most active molecules, proteins and other macromolecules. To date, nanoparticle-assisted delivery has been extensively studied to overcome this challenge but with limited success. On the other hand, for certain brain therapeutic applications, periphery-confined particles could be of immediate therapeutic usefulness. The modulation of CNS dysfunctions from the peripheral compartment is a promising approach, as it does not involve invasive interventions. From recent studies, three main roles could be identified for periphery-confined particles: brain tissue detoxification via the "sink-effect"; a "circulating drug-reservoir" effect to improve drug delivery to brain tissues, and finally, brain vascular endothelium targeting to diagnose or heal vascular-related dysfunctions. These applications are much easier to implement as they do not involve complex therapeutic and targeting strategies and do not require crossing biological barriers. Micro/nano-devices required for such applications will likely be simpler to synthesize and will involve fewer complex materials. Moreover, peripheral particles are expected to be less prone to neurotoxicity and issues related to their diffusion in confined space.

PLGA-PEG-ANG-2 Nanoparticles for Blood-Brain Barrier Crossing: Proof-of-Concept Study

The treatment of diseases that affect the central nervous system (CNS) represents a great research challenge due to the restriction imposed by the blood-brain barrier (BBB) to allow the passage of drugs into the brain. However, the use of modified nanomedicines engineered with different ligands that can be recognized by receptors expressed in the BBB offers a favorable alternative for this purpose. In this work, a BBB-penetrating peptide, angiopep-2 (Ang-2), was conjugated to poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles through pre- and post-formulation strategies. Then, their ability to cross the BBB was qualitatively assessed on an animal model. Proof-of-concept studies with fluorescent and confocal microscopy studies highlighted that the brain-targeted PLGA nanoparticles were able to cross the BBB and accumulated in neuronal cells, thus showing a promising brain drug delivery system.

Influence of surface charge on the formulation of elongated PEG-b-PDLLA nanoparticles

Amphiphilic PEG-PDLLA copolymers undergo assembly into polymersomes and can be transformed into tubular shapes using dialysis. By fine-tuning the shape change conditions also amine- and carboxylic acid modified polymersomes can now be effectively turned into tubes.

Influence of nanoparticles on liver tissue and hepatic functions: A review

Due to the increasing interest in nanotechnology in very large application fields, including biotechnology, electronics and food industries, humans are increasingly exposed to nanoparticles (NPs). Consequently, the question about the safety of these nanomaterials and their impact on human health is a legitimate concern. The liver is the primary organ of detoxification and is one of the tissues that is most exposed to NPs. When they reach the bloodstream, NPs are mainly internalized by liver cells. This review focuses on recent in vitro and in vivo studies addressing the effects of organic and inorganic NPs on the liver. Specifically, the impact of the NPs on hepatic enzyme activities, the inflammatory response and genotoxicity processes will be described. Depending on the physicochemical parameters of the NPs and the conditions of exposure, NPs could lead to global liver injury.

Liposomal delivery of CRISPR/Cas9

Liposomes are one of the most widely investigated carriers for CRISPR/Cas9 delivery. The surface properties of liposomal carriers, including the surface charge, PEGylation, and ligand modification can significantly affect the gene silencing efficiency. Three barriers of systemic CRISPR/Cas9 delivery (long blood circulation, efficient tumor penetration, and efficient cellular uptake/endosomal escape) are analyzed on liposomal carriers with different surface charges, PEGylations, and ligand modifications. Cationic formulations dominate CRISPR/Cas9 delivery and neutral formulations also have good performance while anionic formulations are generally not proper for CRISPR/Cas9 delivery. The PEG dilemma (prolonged blood circulation vs. reduced cellular uptake/endosomal escape) and the side effect of repeated PEGylated formulation (accelerated blood clearance) were discussed. Effects of ligand modification on cationic and neutral formulations were analyzed. Finally, we summarized the achievements in liposomal CRISPR/Cas9 delivery, outlined existing problems, and provided some future perspectives. Liposomes are one of the most widely investigated carriers for CRISPR/Cas9 delivery. The surface properties of liposomal carriers, including the surface charge, PEGylation, and ligand modification can significantly affect the gene silencing efficiency. Three barriers of systemic siRNA delivery (long blood circulation, efficient tumor penetration, and efficient cellular uptake/endosomal escape) are analyzed on liposomal carriers with different surface charges, PEGylations, and ligand modifications. Cationic formulations dominate CRISPR/Cas9 delivery and neutral formulations also have good performance while anionic formulations are generally not proper for CRISPR/Cas9 delivery. The PEG dilemma (prolonged blood circulation vs. reduced cellular uptake/endosomal escape) and the side effect of repeated PEGylated formulation (accelerated blood clearance) were discussed. Effects of ligand modification on cationic and neutral formulations were analyzed. Finally, we summarized the achievements in liposomal CRISPR/Cas9 delivery, outlined existing problems, and provided some future perspectives.

Bioinspired polymer nanoparticles omit biophysical interactions with natural lung surfactant

Herein, we report the attenuated impact of bioinspired nanoparticles on the essential function of lung surfactant. Colloidal particles made from poly(lactide) caused a significant loss of surfactant protein B (and C) from a natural lung surfactant accompanied by a decline in surface activity under static conditions and surface area cycling. No such perturbation of lung surfactant composition and function was observed for polymer nanoparticles coated with bioinspired poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC). More specifically, increasing the PMPC-coating layer thickness (≥3 nm) and density (dense conformation, distance of individual polymer chains of ≤3 nm) on the polymer nanoparticle surface diminished bioadverse events. PMPC-coated poly(lactide) nanoparticles provoked a less severe perturbation of the utilized lung surfactant when compared to colloidal counterparts coated with poly(ethylene glycol). Overall, a steric shielding of colloidal drug delivery vehicles with bioinspired PMPC can be considered as a valuable approach for the rationale development of biocompatible nanomedicines intended for lung delivery.

Biodegradable, Drug-Loaded Nanovectors via Direct Hydration as a New Platform for Cancer Therapeutics

The stabilization and transport of low-solubility drugs, by encapsulation in nanoscopic delivery vectors (nanovectors), is a key paradigm in nanomedicine. However, the problems of carrier toxicity, specificity, and producibility create a bottleneck in the development of new nanomedical technologies. Copolymeric nanoparticles are an excellent platform for nanovector engineering due to their structural versatility; however, conventional fabrication processes rely upon harmful chemicals that necessitate purification. In engineering a more robust (copolymeric) nanovector platform, it is necessary to reconsider the entire process from copolymer synthesis through self-assembly and functionalization. To this end, a process is developed whereby biodegradable copolymers of poly(ethylene glycol)-block-poly(trimethylene carbonate), synthesized via organocatalyzed ring-opening polymerization, undergo assembly into highly uniform, drug-loaded micelles without the use of harmful solvents or the need for purification. The direct hydration methodology, employing oligo(ethylene glycol) as a nontoxic dispersant, facilitates rapid preparation of pristine, drug-loaded nanovectors that require no further processing. This method is robust, fast, and scalable. Utilizing parthenolide, an exciting candidate for treatment of acute lymphoblastic leukemia (ALL), discrete nanovectors are generated that show strikingly low carrier toxicity and high levels of specific therapeutic efficacy against primary ALL cells (as compared to normal hematopoietic cells).

Reassessment of long circulation via monitoring of integral polymeric nanoparticles justifies a more accurate understanding

Monitoring of payloads results in a biased perception of long circulation of nanoparticles. Instead, herein, the long-circulation effect was re-confirmed by monitoring integral nanoparticles, but circulation was not found to be as long as generally perceived. In contrast, disparate pharmacokinetics were obtained by monitoring a model drug, paclitaxel, highlighting the bias of the conventional protocol.

Interspecies differences in the cytochrome P450 activity of hepatocytes exposed to PLGA and silica nanoparticles: an in vitro and in vivo investigation

Nanomedicines represent a promising approach in the treatment and diagnosis of numerous disorders. The majority of the injected dose of nanoparticles (NPs) is sequestrated in the liver. Despite this hepatic tropism, the interaction of NPs with the detoxification function of the liver remains unclear. The present study consists of evaluating the impact of biodegradable poly(lactide-co-glycolide) (PLGA) and silica NPs on cytochrome P450 (CYP) activities. The effects of NPs were evaluated in vitro on human and rat hepatocytes in primary cultures and in vivo by intravenous injections in healthy rats. More than the physicochemical properties, the composition of NPs (organic, inorganic) dramatically influenced the detoxification function of the liver. Silica NPs modulated the CYP activity both in rat and human hepatocytes, in contrast to PLGA NPs. A CYP isoform-dependent effect was reported and the modulation of the metabolic hepatic activity was species-dependent. Human hepatocytes were sensitive to an exposure to PLGA NPs, whereas no marked effect was detected in rat hepatocytes. The in vitro data obtained in rat hepatocytes were correlated with the in vivo data. This study emphasizes the interest to set up relevant in vitro models using human hepatic cells to evaluate the hepatotoxicity of nanomedicines.

Current developments and applications of microfluidic technology toward clinical translation of nanomedicines

Nanoparticulate drug delivery systems hold great potential for the therapy of many diseases, especially cancer. However, the translation of nanoparticulate drug delivery systems from academic research to industrial and clinical practice has been slow. This slow translation can be ascribed to the high batch-to-batch variations and insufficient production rate of the conventional preparation methods, and the lack of technologies for rapid screening of nanoparticulate drug delivery systems with high correlation to the in vivo tests. These issues can be addressed by the microfluidic technologies. For example, microfluidics can not only produce nanoparticles in a well-controlled, reproducible, and high-throughput manner, but also create 3D environments with continuous flow to mimic the physiological and/or pathological processes. This review provides an overview of the microfluidic devices developed to prepare nanoparticulate drug delivery systems, including drug nanosuspensions, polymer nanoparticles, polyplexes, structured nanoparticles and theranostic nanoparticles. We also highlight the recent advances of microfluidic systems in fabricating the increasingly realistic models of the in vivo milieu for rapid screening of nanoparticles. Overall, the microfluidic technologies offer a promise approach to accelerate the clinical translation of nanoparticulate drug delivery systems.

Modulating Phagocytic Cell Sequestration by Tailoring Nanoconstruct Softness

The effect of nanoparticle size, shape, and surface properties on cellular uptake has been extensively investigated for its basic science and translational implications. Recently, softness is emerging as a design parameter for modulating the interaction of nanoparticles with cells and the biological microenvironment. Here, circular, quadrangular, and elliptical polymeric nanoconstructs of different sizes are realized with a Young's modulus ranging from ∼100 kPa (soft) to 10 MPa (rigid). The interaction of these nanoconstructs with professional phagocytic cells is assessed via confocal microscopy and flow cytometry analyses. Regardless of the size and shape, softer nanoconstructs evade cellular uptake up to 5 times more efficiently, by bone-marrow-derived monocytes, as compared to rigid nanoconstructs. Soft circular and quadrangular nanoconstructs are equally uptaken by professional phagocytic cells (<15%); soft elliptical particles are more avidly internalized (<60%) possibly because of the larger size and elongated shape, whereas over 70% of rigid nanoconstructs of any shape and size are uptaken. Inhibition of actin polymerization via cytochalasin D reduces the internalization propensity for all nanoconstruct types. High-resolution live cell microscopy documents that soft nanoconstructs mostly establish short-lived (<30 s) interactions with macrophages, thus diminishing the likelihood of recognition and internalization. The bending stiffness is identified as a discriminating factor for internalization, whereby particles with a bending stiffness slightly higher than cells would more efficiently oppose internalization as compared to stiffer or softer particles. These results confirm that softness is a key parameter in modulating the behavior of nanoparticles and are expected to inspire the design of more efficient nanoconstructs for drug delivery, biomedical imaging, and immunomodulatory therapies.

The role of hydrophobic modification on hyaluronic acid dynamics and self-assembly

The advent of nanomedicine has rejuvenated the need for increased understanding of the fundamental physicochemical properties of polymeric amphiphiles. Hyaluronic acid (HA) is a hydrophilic polysaccharide that is frequently conjugated to hydrophobic moieties and then used to entrap dyes and therapeutics. Here, we develop computational models to examine the effects of the hydrophobic modification on supramolecular behavior among three systematically designed HA derivatives substituted with alkyl chains of increasing length. Our simulations coalesce with experimentally obtained results to demonstrate the dependence of supramolecular behavior on intramolecular forces. We show that the formation of clearly defined hydrophobic domains in samples of octadecylamine-modified HA compared to HA conjugates with shorter alkyl chains is a result of more favorable hydrophobic interactions. Trends in hydrodynamic radius and polydispersity are observed in experimental results that coalesce with theoretical calculations, suggesting that supramolecular properties are dependent on the physicochemical characteristics of individual polymer strands.

Compatibility of PEGylated Polymer Nanoparticles with the Biophysical Function of Lung Surfactant

To minimize an unwanted interference of colloidal drug delivery vehicles with the biophysical functionality of lung surfactant, the surface of polymer nanoparticles was modified with poly(ethylene glycol) (PEGylation). Plain poly(lactide) nanoparticles provoked a statistically relevant decrease in the surface activity of the naturally derived lung surfactant, Alveofact. By contrast, the extent of lung surfactant inhibition induced by PEGylated polymer nanoparticles was significantly attenuated. Here, escalations of the PEG coating layer thickness (>3 nm, with a chain-to-chain distance of ≤4 nm) on the colloidal surface were capable of circumventing bioadverse effects. Accordingly, polymer nanoparticles equipped with PEG chains with a molecular weight above 2-5 kDa were compatible with the biophysical function of Alveofact. Overall, PEGylation of polymer nanoparticles presents a promising approach for the development of inhalation nanomedicines revealing negligible effects on the surface activity of the lining layer present in the deep lungs.

Multimodal Imaging Nanoparticles Derived from Hyaluronic Acid for Integrated Preoperative and Intraoperative Cancer Imaging

Surgical resection remains the most promising treatment strategy for many types of cancer. Residual malignant tissue after surgery, a consequence in part due to positive margins, contributes to high mortality and disease recurrence. In this study, multimodal contrast agents for integrated preoperative magnetic resonance imaging (MRI) and intraoperative fluorescence image-guided surgery (FIGS) are developed. Self-assembled multimodal imaging nanoparticles (SAMINs) were developed as a mixed micelle formulation using amphiphilic HA polymers functionalized with either GdDTPA for T₁ contrast-enhanced MRI or Cy7.5, a near infrared fluorophore. To evaluate the relationship between MR and fluorescence signal from SAMINs, we employed simulated surgical phantoms that are routinely used to evaluate the depth at which near infrared (NIR) imaging agents can be detected by FIGS. Finally, imaging agent efficacy was evaluated in a human breast tumor xenograft model in nude mice, which demonstrated contrast in both fluorescence and magnetic resonance imaging.

Poloxamer-Decorated Polymer Nanoparticles for Lung Surfactant Compatibility

Lung-delivered polymer nanoparticles provoked dysfunction of the essential lung surfactant system. A steric shielding of the nanoparticle surface with poloxamers could minimize the unwanted interference of polymer nanoparticles with the biophysical function of lung surfactant. The extent of poly(styrene) and poly(lactide) nanoparticle-induced lung surfactant inhibition could be related to the type and content of the applied poloxamer. Escalations of the adsorbed coating layer thickness (>3 nm) as well as concentration (brush- rather than mushroom-like conformation of poly(ethylene glycol), chain-to-chain distance of <5 nm) on the colloidal surface were capable of circumventing bioadverse effects. Accordingly, specific formulations (i.e., poloxamer 188, 338, and 407) avoided a perturbation of the microstructure and surface activity of Alveofact and a depletion of the content of surfactant-associated proteins. Poloxamer-modified polymer nanoparticles represent a promising nanomedicine platform intended for respiratory delivery revealing negligible effects on the biophysical functionality of the lining layer present in the deep lungs.

Development of Halofluorochromic Polymer Nanoassemblies for the Potential Detection of Liver Metastatic Colorectal Cancer Tumors Using Experimental and Computational Approaches

PURPOSE

To develop polymer nanoassemblies (PNAs) modified with halofluorochromic dyes to allow for the detection of liver metastatic colorectal cancer (CRC) to improve therapeutic outcomes.

METHODS

We combine experimental and computational approaches to evaluate macroscopic and microscopic PNA distributions in patient-derived xenograft primary and orthotropic liver metastatic CRC tumors. Halofluorochromic and non-halofluorochromic PNAs (hfPNAs and n-hfPNAs) were prepared from poly(ethylene glycol), fluorescent dyes (Nile blue, Alexa546, and IR820), and hydrophobic groups (palmitate), all of which were covalently tethered to a cationic polymer scaffold [poly(ethylene imine) or poly(lysine)] forming particles with an average diameter < 30 nm.

RESULTS

Dye-conjugated PNAs showed no aggregation under opsonizing conditions for 24 h and displayed low tissue diffusion and cellular uptake. Both hfPNAs and n-hfPNAs accumulated in primary and liver metastatic CRC tumors within 12 h post intravenous injection. In comparison to n-hfPNAs, hfPNAs fluoresced strongly only in the acidic tumor microenvironment (pH < 7.0) and distinguished small metastatic CRC tumors from healthy liver stroma. Computational simulations revealed that PNAs would steadily accumulate mainly in acidic (hypoxic) interstitium of metastatic tumors, independently of the vascularization degree of the tissue surrounding the lesions.

CONCLUSION

The combined experimental and computational data confirms that hfPNAs detecting acidic tumor tissue can be used to identify small liver metastatic CRC tumors with improved accuracy.

Impact of triblock copolymers on the biophysical function of naturally-derived lung surfactant

The current study aimed at investigating the general applicability of triblock copolymers consisting of poly(ethylene glycol) and poly(propylene glycol) (Pluronic^®) as excipients for lung delivery. After thorough physicochemical characterization of the diverse polymers, their cytotoxicity was evaluated using alveolar epithelial cells. Next, a naturally-derived lung surfactant was challenged with the distinct triblock copolymers with respect to changes in microstructure, adsorption to the air/liquid interface and dynamic surface tension behavior under bubble pulsation. Biocompatibility assessment of triblock copolymers in A549 cells demonstrated some cytotoxicity, dependent on the hydrophobicity and dose of the substance applied (effective at ≥0.1mg/ml). Supplementing triblock copolymers onto Alveofact^® had an obvious influence on the aggregation state and surface activity (>25 and >5mN/m during adsorption and bubble pulsation, respectively) of the lung surfactant. Interestingly, Pluronic^® F127, a rather hydrophilic triblock copolymer, showed the most intense effect on the microstructure and biophysical performance of Alveofact^®. This is likely due to the synergistic interplay of its low critical micelle concentration and rather high molecular weight, leading to the penetration of lung surfactant film/vesicles and accompanied by a partial replacement of relevant surfactant components from the air/liquid interface. Overall, suitable compositions and concentrations of triblock copolymers were identified with respect to compatibility with the physiological environment of the deep lungs.

Microfluidic-assisted fabrication of carriers for controlled drug delivery

The microfluidic technique has brought unique opportunities toward the full control over the production processes for drug delivery carriers, owing to the miniaturisation of the fluidic environment. In comparison to the conventional batch methods, the microfluidic setup provides a range of advantages, including the improved controllability of material characteristics, as well as the precisely controlled release profiles of payloads. This review gives an overview of different fluidic principles used in the literature to produce either polymeric microparticles or nanoparticles, focusing on the materials that could have an impact on drug delivery. We also discuss the relations between the particle size and size distribution of the obtained carriers, and the design and configuration of the microfluidic setups. Overall, the use of microfluidic technologies brings exciting opportunities to expand the body of knowledge in the field of controlled drug delivery and great potential to clinical translation of drug delivery systems.

Prevention of Oxidized Low Density Lipoprotein-Induced Endothelial Cell Injury by DA-PLGA-PEG-cRGD Nanoparticles Combined with Ultrasound

In general, atherosclerosis is considered to be a form of chronic inflammation. Dexamethasone has anti-inflammatory effects in atherosclerosis, but it was not considered for long-term administration on account of a poor pharmacokinetic profile and adverse side effects. Nanoparticles in which drugs can be dissolved, encapsulated, entrapped or chemically attached to the particle surface have abilities to incorporate dexamethasone and to be used as controlled or targeted drug delivery system. Long circulatory polymeric nanoparticles present as an assisting approach for controlled and targeted release of the encapsulated drug at the atherosclerotic site. Polymeric nanoparticles combined with ultrasound (US) are widely applied in cancer treatment due to their time applications, low cost, simplicity, and safety. However, there are few studies on atherosclerosis treatment using polymeric nanoparticles combined with US. In this study, targeted dexamethasone acetate (DA)-loaded poly (lactide-glycolide)-polyethylene glycol-cRGD (PLGA-PEG-cRGD) nanoparticles (DA-PLGA-PEG-cRGD NPs) were prepared by the emulsion-evaporation method using cRGD modified PLGA-PEG polymeric materials (PLGA-PEG-cRGD) prepared as the carrier. The average particle size of DA-PLGA-PEG-cRGD NPs was 221.6 ± 0.9 nm. Morphology of the nanoparticles was spherical and uniformly dispersed. In addition, the DA released profiles suggested that ultrasound could promote drug release from the nanocarriers and accelerate the rate of release. In vitro, the cellular uptake process of fluorescein isothiocyanate (FITC)@DA-PLGA-PEG-cRGD NPs combined with US into the damaged human umbilical vein endothelial cells (HUVECs) indicated that US promoted rapid intracellular uptake of FITC@DA- PLGA-PEG-cRGD NPs. The cell viability of DA-PLGA-PEG-cRGD NPs combined with US reached 91.9% ± 0.2%, which demonstrated that DA-PLGA-PEG-cRGD NPs combined with US had a positive therapeutic effect on damaged HUVECs. Overall, DA-PLGA-PEG-cRGD NPs in combination with US may provide a promising drug delivery system to enhance the therapeutic effects of these chemotherapeutics at the cellular level.

Liquid formulation containing doxorubicin-loaded lipid-core nanocapsules: Cytotoxicity in human breast cancer cell line and in vitro uptake mechanism

Cancer is a major public health problem in the world, being breast cancer the most frequent cancer affecting women. Despite advances in detection and treatment, mortality rates remain high. Therefore, new approaches for breast cancer treatments are necessary. In this study, our objective was to develop a liquid formulation containing doxorubicin-loaded lipid-core nanocapsules (DOX-LNC), to evaluate the in vitro antiproliferative activity and to determine the nanocapsules uptake by MCF-7 cells. Lipid-core nanocapsules (LNC), blank formulation, and DOX-LNC, proposed treatment, were prepared by self-assembling using the solvent displacement method. Hydrodynamic mean diameters (z-average) were respectively 191±31nm and 230±23nm presenting narrow size distributions. Drug content was 0.102±0.029mgmL^-1 with an encapsulation efficiency higher than 90%. Formulations were applied to semiconfluent MCF-7 cells. After 24h, LNC showed no cytotoxicity, while DOX-LNC showed an IC₅₀ of 4.49 micromolar. After 72h of incubation, DOX-LNC showed an IC₅₀ of 1.60 micromolar demonstrating a sustained effect. The nanocapsules were internalized by endocytosis mediated by caveolin and by fluid phase endocytosis, which are active transport mechanisms. In conclusion, the liquid formulation containing DOX-LNC showed to be a promising product for the breast cancer treatment opening new avenues for further in vivo studies.

PEGylated and Functionalized Aliphatic Polycarbonate Polyplex Nanoparticles for Intravenous Administration of HDAC5 siRNA in Cancer Therapy

Guanidine and morpholine functionalized aliphatic polycarbonate polymers are able to deliver efficiently histone deacetylase 5 (HDAC5) siRNA into the cytoplasm of cancer cells in vitro leading to a decrease of cell proliferation were previously developed. To allow these biodegradable and biocompatible polyplex nanoparticles to overcome the extracellular barriers and be effective in vivo after an intravenous injection, polyethylene glycol chains (PEG₇₅₀ or PEG₂₀₀₀) were grafted on the polymer structure. These nanoparticles showed an average size of about 150 nm and a slightly positive ζ-potential with complete siRNA complexation. Behavior of PEGylated and non-PEGylated polyplexes were investigated in the presence of serum, in terms of siRNA complexation (fluorescence correlation spectroscopy), size (dynamic light scattering and single-particle tracking), interaction with proteins (isothermal titration calorimetry) and cellular uptake. Surprisingly, both PEGylated and non-PEGylated formulations presented relatively good behavior in the presence of fetal bovine serum (FBS). Hemocompatibility tests showed no effect of these polyplexes on hemolysis and coagulation. In vivo biodistribution in mice was performed and showed a better siRNA accumulation at the tumor site for PEGylated polyplexes. However, cellular uptake in protein-rich conditions showed that PEGylated polyplex lost their ability to interact with biological membranes and enter into cells, showing the importance to perform in vitro investigations in physiological conditions closed to in vivo situation. In vitro, the efficiency of PEGylated nanoparticles decreases compared to non-PEGylated particles, leading to the loss of the antiproliferative effect on cancer cells.

A tumour microenvironment-responsive polymeric complex for targeted depletion of tumour-associated macrophages (TAMs)

A dual-level targeting polymeric system to eliminate tumour-associated macrophages.

Anti-phagocytosis and tumor cell targeting micelles prepared from multifunctional cell membrane mimetic polymers

“Stealthy bio-missile” kinds of micelles were fabricated for developing advanced anticancer formulations by cell membrane mimicking.