Nanosized Drug Carriers Research Articles

Design, characterization, and intracellular trafficking of biofunctionalized chitosan nanomicelles.

The hydrophobically modified glycol chitosan (HGC) nanomicelle has received increasing attention as a promising platform for the delivery of chemotherapeutic drugs. To improve the tumor selectivity of HGC, here an avidin and biotin functionalization strategy was applied. The hydrodynamic diameter of the biotin-avidin-functionalized HGC (cy5.5-HGC-B4F) was observed to be 104.7 nm, and the surface charge was +3.1 mV. Confocal and structured illumination microscopy showed that at 0.1 mg/ml, cy5.5-HGC-B4F nanomicelles were distributed throughout the cytoplasm of MDA-MB-231 breast cancer cells after 2 h of exposure without significant cytotoxicity. To better understand the intracellular fate of the nanomicelles, entrapment studies were performed and demonstrated that some cy5.5-HGC-B4F nanomicelles were capable of escaping endocytic vesicles, likely via the proton sponge effect. Quantitative analysis of the movements of endosomes in living cells revealed that the addition of HGC greatly enhanced the motility of endosomal compartments, and the nanomicelles were transported by early and late endosomes from cell periphery to the perinuclear region. Our results validate the importance of using live-cell imaging to quantitatively assess the dynamics and mechanisms underlying the complex endocytic pathways of nanosized drug carriers.

Nucleic acid biohybrid nanocarriers with high-therapeutic payload and controllable extended release of daunomycin for cancer therapy.

We have developed a novel, nanosized drug carrier with high-therapeutic payload, controllable release, and the potential for active tumor targeting. It consists of a 15 nm gold nanoparticle with dense surface loading of DNA duplexes. We utilize the natural intercalating behavior of daunomycin to load the drug between DNA base pairs. We obtained a high-therapeutic payload of >1,000 drug molecules per gold nanoparticle (AuNP), one of the highest loadings reported in literature to date. We have engineered unique DNA sequences to control release of daunomycin for over 48 hr and show higher cell death compared to equivalent concentrations of free daunomycin. We have also explored cell internalization mechanisms to identify the pathways by which our gold nanoparticles enter the cell. This nanocarrier is in the ideal size range of 16-100 nm in diameter to utilize the enhanced permeability and retention effect for passive targeting to tumors. Our AuNP platform is effective as a therapeutic drug delivery device and can easily incorporate any aptamer of choice through complementary base pairing. Our work has produced an innovative nanoscale drug-delivery platform potentially leading to personalized cancer therapies through careful selection of aptamers and an adjustable drug release profile.

Extracellular Vesicles - Advanced Nanocarriers in Cancer Therapy: Progress and Achievements.

Extracellular vesicles (EVs) are a class of cell-derived, lipid bilayer membrane composed vesicles, and some of them such as exosomes and ectosomes have been proven, playing remarkable roles in transmitting intercellular information, and being involved in each property of cell physiological activities. Nowadays, EVs are considered as potential nanocarriers which could partially resolve the problems of current chemotherapy because of their distinctive advantages. As endogenous membrane encompassed vesicles with nanosize, EVs are able to pass through the natural barriers with prolonged circulation time in vivo and have intrinsic cell targeting properties, they are less toxic, and less immunogenic. Recently, studies focusing on EV-based drug delivery system for cancer therapy have exploded dramatically. This review aims to outline the current applications of EVs as potential nanosized drug carriers in cancer therapy. Firstly, the characteristics and biofunctions of each EV subtype are described. Then the variety of therapeutic cargoes, the loading methods, and the targeting strategy of engineered EVs are emphatically introduced. Thereafter the pros and cons of EVs applied as therapeutic carriers, as well as the future prospects in this field, are discussed.

Enhanced Antitumor Efficacy of Curcumin-Loaded PLGA Nanoparticles Coated with Unique Fungal Hydrophobin.

Modifications to the surface chemistry, charge, and hydrophilicity/hydrophobicity of nanoparticles are applicable approaches to the alterations of the in vivo fate of intravenously administered nano-sized drug carriers. The objective of this study is to investigate the in vitro and in vivo antitumor efficacies of curcumin PLGA nanoparticles in relation to their surface structural modification via self-assembling coating with unique fungal hydrophobin. The hydophobin-coated curcumin PLGA nanoparticles (HPB PLGA NPs) were obtained by simply soaking curcumin-loaded PLGA nanoparticles (PLGA NPs) in aqueous fungal hydrophobin solution. The in vitro drug release behavior of the HPB PLGA NPS was also tested. The cytotoxicity and cellular uptake of these nanoparticles were determined in HepG2, A549, and Hela cell lines using MTT assay method and CLSM observation. The in vivo antitumor activity was evaluated in Hela tumor xenografted mice model. Compared with the PLGA NPs, the size and zeta potential of the nanoparticles were changed after hydrophobin coating, whereas similar in vitro release pattern was observed. The pharmacodynamics study showed prolonged blood retention of both nano-formulations than that of free curcumin, but no significant difference between the hydrophobin coated and uncoated nanoparticles. It was found that HPB PLGA NPs had increased cytotoxicities, higher cellular uptake, and improved antitumor efficacy. Surface modification of nanoparticles via self-assembling of hydrophobin is a convenient and promising method of changing particle surface physiochemical properties and antitumor performances. Further investigations, especially on tissue distribution, were needed to assess the potential application of the hydrophobin self-assembling coating in nano-drug delivery carriers.

Hyperbranched polyglycerol β-cyclodextrin as magnetic platform for optimization of doxorubicin cytotoxic effects on Saos-2 bone cancerous cell line

In recent years, cancer has become the most important human health problems in the world. To overcome these problems, chemotherapy as a treatment approach is widely used in cancer treatment. However, single chemotherapy have a toxic side effects without completely effectiveness. This study has focused on the mitigating of doxorubicin side effects by designing pH-sensitive magnetic hyperbranched β-cyclodextrin as a nano-sized drug carrier. The accuracy of samples preparation has been confirmed by several characterizations including FTIR, NMR, SEM, EDX, TEM, XRD, DLS and Zeta Potential tests. The hemolysis assay results have shown that synthesized nanocarrier is completely biocompatible and could be used in blood contacting applications. In this case, nanoparticles have a better release in acidic pH value. In-vitro studies including MTT assay uptake assay, DAPI staining and apoptosis assay by flow-cytometry have been carried out on Saos-2 cell line. It is concluded that a synthesized doxorubicin-loaded nanocarrier has more cytotoxicity than free doxorubicin after incubation time, showing its high potentiality for target doxorubicin delivery to Saos-2 cell line.

In vitro and in vivo evaluation of levodopa-loaded nanoparticles for nose to brain delivery

Parkinson’s disease (PD) is a neurodegenerative disease which is characterized by the loss of dopaminergic neurons in the brain. Levodopa is the drug of choice in the treatment of PD but it exhibits low oral bioavailability (30%) and very low brain uptake due to its extensive metabolism by aromatic amino acid decarboxylase in the peripheral circulation. Moreover, levodopa has psychic, gastrointestinal, and cardiovascular side effects, and most importantly, short and frequent stimulation of dopamine receptors lead to undesirable conditions such as dyskinesia over time. The challenges are to increase the therapeutic efficiency, the bioavailability and decreasing the unfavourable side effects of levodopa. Biocompatible nano-sized drug carriers could address these challenges at molecular level. For this purpose, levodopa-loaded Poly (lactide-co-glycolide) acid nanoparticles were prepared by double emulsion-solvent evaporation method for nose to brain drug delivery. Parameters such as homogenization speed, and external and internal phase content were modified to reach the highest loading efficiency. F1-1 coded formulation showed prolonged release up to 9 h. Carbodiimide method was used for surface modification studies of nanoparticles. The efficacy of the selected nanoparticle formulation has been demonstrated by in vivo experiments in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine induced PD model in mice.

Interactions at the cell membrane and pathways of internalization of nano-sized materials for nanomedicine.

Nano-sized materials have great potential as drug carriers for nanomedicine applications. Thanks to their size, they can exploit the cellular machinery to enter cells and be trafficked intracellularly, thus they can be used to overcome some of the cellular barriers to drug delivery. Nano-sized drug carriers of very different properties can be prepared, and their surface can be modified by the addition of targeting moieties to recognize specific cells. However, it is still difficult to understand how the material properties affect the subsequent interactions and outcomes at cellular level. As a consequence of this, designing targeted drugs remains a major challenge in drug delivery. Within this context, we discuss the current understanding of the initial steps in the interactions of nano-sized materials with cells in relation to nanomedicine applications. In particular, we focus on the difficult interplay between the initial adhesion of nano-sized materials to the cell surface, the potential recognition by cell receptors, and the subsequent mechanisms cells use to internalize them. The factors affecting these initial events are discussed. Then, we briefly describe the different pathways of endocytosis in cells and illustrate with some examples the challenges in understanding how nanomaterial properties, such as size, charge, and shape, affect the mechanisms cells use for their internalization. Technical difficulties in characterizing these mechanisms are presented. A better understanding of the first interactions of nano-sized materials with cells will help to design nanomedicines with improved targeting.

Chitosan-modified hyaluronic acid-based nanosized drug carriers

Fabrication possibilities, detailed size and structural characterization of biodegradable chitosan (Chit) polysaccharide-modified hyaluronic acid (HyA)-based colloidal carriers are demonstrated. The negatively charged and highly hydrophilic HyA polymer chains have been ionically modified by positively charged pure Chit and crosslinked Chit macromolecules at various Chit/HyA weight ratios, which resulted in the formation of carrier nanoparticles (NPs) having three different nanostructures depending on the polymer concentrations. Electrostatically-compensated Chit/HyA polymer coils with loose colloidal structure, tripolyphosphate (TPP)-crosslinked Chit-TPP/HyA NPs having interpenetrating polymer network and well-defined Chit-TPPcore-HyAshell NPs with diameters of 100–300 nm were also prepared and were loaded with tocopherol (TCP) and cholecalciferol (D3) having Vitamin E and D activity, respectively. By using rheological, particle charge titration and conductivity studies we first confirmed that the expected 1:1 Chit/HyA monomer molar ratio is strongly influenced by the pH of the polymer solutions as well as the deacetylation degree of Chit which are crucial factors for the solubility, purity and the quality of the commercially available biocompatible Chit in aqueous medium. Encapsulation studies revealed that D3 could be better incorporated in every system, especially in Chit-TPP/HyA NPs, while for TCP the simple Chit/HyA polymer coils were the most promising carriers.

Recent Advances in Nanocapsule: Types, Preparation Methods and Characterizatio

Nanocapsules are submicroscopic colloidal drug carrier systems consist of a liquid/solid core in which the drug, gene, protein, and other substances are incorporated into the interior cavity that is surrounded by a distinctive polymeric membrane. Polymers like collagen, albumin, and gelatin are mainly using polymers in nanocapsule formulations. Nanocapsules can serve as nano-sized drug carriers to achieve controlled release as well as efficient drug targeting. The process is used to improve the poor aqueous drug solubility, taste, stabilizing drugs by protecting the molecule from the environment, providing the desired pharmacokinetic profile, allowing controlled release, as well as facilitating oral administration. Capsules are generally prepared between the range of 100 and 1000 nm. Their release and degradation properties largely depend on the composition and the structure of the capsule walls. The dispersion stability of nanocapsules determined by the surfactant, nature of the outer coating. This review describes various facts of nanocapsule drug delivery systems in relation to the method of formulation, characterization, potential benefits and risks, and pharmaceutical applications in drug delivery.

Limits and challenges in using transport inhibitors to characterize how nano-sized drug carriers enter cells.

Aim: In this work we illustrate limits and challenges associated with the use of pharmacological inhibitors to study how nanomedicines enter cells and show how such limits can be overcome. Materials & methods: We selected a panel of six common pharmacological inhibitors and a model nanoparticle-cell system. We tested eventual toxicity by measuring cell viability. We confirmed drug efficacy by measuring the uptake of control markers for the pathways involved by flow cytometry and fluorescence microscopy. Results & conclusion: We show how to optimize the use of pharmacological inhibitors and interpret the results generated. Furthermore, we demonstrate that some inhibitors cannot be used for nanomedicine studies because they lose their efficacy when serum is added, as required for nanoparticle exposure to cells.

Quality by Design Approach Using Multiple Linear and Logistic Regression Modeling Enables Microemulsion Scale Up.

The development of pharmaceutical nanoformulations has accelerated over the past decade. However, the nano-sized drug carriers continue to meet substantial regulatory and clinical translation challenges. In order to address some of these key challenges in early development, we adopted a quality by design approach to develop robust predictive mathematical models for microemulsion formulation, manufacturing, and scale-up. The presented approach combined risk management, design of experiments, multiple linear regression (MLR), and logistic regression to identify a design space in which microemulsion colloidal properties were dependent solely upon microemulsion composition, thus facilitating scale-up operations. Developed MLR models predicted microemulsion diameter, polydispersity index (PDI), and diameter change over 30 days storage, while logistic regression models predicted the probability of a microemulsion passing quality control testing. A stable microemulsion formulation was identified and successfully scaled up tenfold to 1L without impacting droplet diameter, PDI, or stability.

Characterization of Nanosized Drug Carriers by Analytical Centrifugation

Correct size characterization is a main prerequisite in the field of pharmaceutical nanotechnology. Different methods exist and each method possesses beneficial properties but also some drawbacks. Typical drawbacks are for example a narrow measuring range, which hampers the detection of possible larger particles or the lack to determine size distributions. Therefore, a thorough and reliable size characterization can only be performed by combining different sizing methods. Analytical centrifugation is a relatively novel technology in the field of pharmaceutics and can be used for the characterization of submicron particles. The aim of this study is to investigate if analytical centrifugation is a useful and reliable tool for size analysis of pharmaceutical nanocarriers. Different samples of known composition, that is mono‐, bi‐, tri‐, and tetramodal samples, which are prepared from differently sized particle standards, and different drug nanocarrier systems are characterized by dynamic light scattering and by analytical centrifugation. Analytical centrifugation led to accurate size results and is found to detect all larger sized submicron particles within a small sized main population reliably, when samples with standard particles are analyzed. Size characterization of the different drug nanocarriers is not superior, when compared to classical sizing methods.

Development of Noninvasive Drug Delivery Systems to the Brain for the Treatment of Brain/Central Nervous System Diseases

In general, the blood-brain barrier (BBB) poses a major challenge to drug development efforts targeting brain/central nervous system (CNS) diseases, since it limits the distribution of systemically administered therapeutics to the brain/ CNS. Therefore, the development of effective strategies for enhancing drug delivery to the brain has been a topic of great interest in both the clinical and pharmaceutical fields. Intranasal administration has been noted as a method for noninvasive delivery of a drug to the brain/CNS by bypassing the BBB via the "nose-to-brain" route. This nose-to-brain delivery system has the potential to be highly versatile, and a combination of this system with new drugs and siRNA shows promise in the treatment of CNS diseases. Cell-penetrating Tat peptide-modified block copolymer micelles have the potential for improving mucosal permeability and nose-to-brain transport efficiency. In addition, nano-sized drug carriers can improve nose-to-brain delivery through their ability to increase the stability of encapsulated drugs against biological degradation in the nasal cavity and brain/CNS. In this review, we introduce the assessment of and mechanisms for delivery to the brain after intranasal drug/siRNA administration with our cell-penetrating peptide-modified nano-sized polymer micelles. Our findings show that the use of polymer micelles with surface modification by cell-penetrating peptides for intranasal administration enables the noninvasive delivery of therapeutic agents to the brain/CNS by increasing the nose-to-brain transfer of the drug or siRNA administered from the nasal cavity.

Nanocarrier for levodopa Parkinson therapeutic drug; comprehensive benserazide analysis

Loss of dopamine-secreting neurons in the midbrain causes Parkinson’s disease. L-DOPA, the precursor to the neurotransmitters dopamine, crosses vast majority of physiological and biochemical barriers that dopamine cannot. But most levodopa is decarboxylated to dopamine before it reaches the brain. This causes to little therapeutic gain with strong peripheral side effects. Benserazide is an irreversible inhibitor of peripheral aromatic L-amino acid decarboxylase that prevents the breakdown of levodopa in the bloodstream. The challenges are to increase the therapeutic efficiency, the bioavailability and decreasing the unfavourable side effects of Levodopa drug. Biocompatible nano-sized drug carriers could address these challenges at molecular level. Thus calculations of drug loading ability of acid-functionalized CNT for the benserazide as a nanodug carrier complex for L-DOPA were performed. In this regard, evaluation of all adsorption features of the most stable conformer of benserazide molecule onto carboxylated carbon nanotube is critical. To determine the minimum energy conformer of benserazide, the molecular structure and conformational analysis of 512 possible conformers have been subjected to first principle quantum mechanical calculations. Our work established a novel and easy-to-make formulation of benserazide/carboxylated CNT conjugate with extremely high drug loading efficiency of Levodopa for Parkinson disease treatment.

A comparison of the lung clearance kinetics of solid lipid nanoparticles and liposomes by following the 3H-labelled structural lipids after pulmonary delivery in rats

The utility of biodegradable nanosized drug carriers for the local and controlled delivery of therapeutics to the lungs has prompted significant interest in the development of inhalable nanomedicines. Still, little is known about how these systems are cleared from the lungs, including the kinetics of the structural lipids. Most preclinical and clinical studies to date have evaluated the lung clearance of loaded drugs, which in many cases poorly reflects the kinetics of the nanocarrier, or the bulk-labelled particles. This study therefore aimed to describe and compare the pulmonary pharmacokinetic behaviour and patterns of lung clearance of two commonly explored inhalable nanocarriers (anionic ∼150 nm liposomes and solid lipid nanoparticles [SLNs]) in rats by following the 3H-labelled structural lipids (phosphatidylcholine and tristearin respectively). The data showed that SLNs and liposomes were cleared from the lungs at similar rates, despite SLNs being deposited after intratracheal instillation in the upper respiratory track, and primarily via the mucociliary escalator, but this process was more pronounced for SLNs. Structural lipids were mainly associated with plasma proteins rather than nanocarrier in plasma. The lipids also exhibit prolonged lung exposure and are associated with the lung tissue (rather than BALF) over 2 weeks.

Cancer Therapeutic Proficiency of Dual-Targeted Mesoporous Silica Nanocomposite Endorses Combination Drug Delivery

The cargo-loaded mesoporous silica nanoparticles (MSNs) with convenient surface modification can facilitate the development of the innovative nanodrug system. Herein, the present investigation described the electrostatically self-assembled MSNs as a nanosized drug carrier to realize potent synergistic chemotherapy based on the specificity in targeting cytoplasm and nucleus of tumor cells. In this context, the primarily constructed MSNs were subjected with anticancer drug topotecan (TPT) into its large pores. Then, the selective TAT peptide (a nuclear localization signal peptide) was anchored onto TPT-loaded MSNs (TPT-MSN). Subsequently, the positive surface of TPT-MSN-TAT was capped with negatively charged components, poly(acrylic acid) (PAA)-cRGD peptide and citraconic anhydride (CAH)-metformin (MT), and acted as a smart gatekeeper. Comparatively, PAA-cRGD attached onto MSNs serving as the targeted molecules could upsurge by invasion into cancer cells. Interestingly, the acidic pH of the lysosomal compartment in tumor cells triggers the conjugated CAH from the polymer decorated mesoporous silica (PMS) nanocomposite and could efficiently release MT into the cytoplasm. Consequently, the remaining TPT-MSN-TAT efficiently targets the nucleus and delivers the TPT to improve synergistic chemotherapeutic effects. The precisely released drugs were individually enhanced in the in vitro and in vivo cell killing efficiencies. Thus, the study provides a potential drug delivery podium through combined drugs to realize cancer cell targeting approach.

Nanocarriers: Capturing “Extraordinary” Soft‐Assembled Charge‐Like Polypeptides as a Strategy for Nanocarrier Design (Adv. Mater. 39/2017)

A novel strategy developed by Vicent J. Nebot, María J. Vicent, and co-workers in article number 1702888 to produce nanosized drug carriers may improve the anticancer drug activity of polymer therapeutics and patient treatment. The discovery of an attractive force between negatively charged star-shaped-polypeptides allows single stars to self-assemble into unprecedented larger spherical structures with enhanced pharmacokinetic characteristics. Furthermore, selective lymph-node accumulation of these carriers may lead to applications in anti-metastatic and immunotherapeutic strategies.

Nano-sized drug carriers: Extravasation, intratumoral distribution, and their modeling

Navigating intratumoral drug distribution has proven to be one of the most challenging aspects of drug delivery. The barriers are significant and varied; increased diffusional distances, elevated interstitial fluid pressure, regions of dense extracellular matrix and high cell density, and overall heterogeneity. Such a long list imposes significant requirements on nano-sized carriers. Unfortunately, other capabilities are eclipsed by the distribution requirements. A drug can do no good until it reaches its target. Numerous strategies to improve drug distribution have been developed, taking account of various unique characteristics of solid tumors, including some mechanisms that are still not fully understood. Most of these strategies were from small animal tumor models which are our primary tool for understanding cancer physiology. The small animal tumor model is the most versatile and effective means of understanding tumor transport, but its prevalence belies some of its weaknesses. Tumors grown under lab conditions are developed much more quickly than naturally developed cancers, potentially impacting tumor heterogeneity, blood vessel development, extracellular matrix organization, cell diversity, and many other features of structure and physiology that may impact transport. These problems come in addition to the difficulties of making precise measurements within a living tumor. Resolving these problems is best done by improving our analysis methods, and by finding complementary models that can clarify and expound the details. In this review, we will first discuss some of the strategies employed to improve transport and then highlight some of the new models that have recently been developed in the Bae lab and how they may aid in the study of tumor transport in the future.

Enhancement of nose-to-brain delivery of hydrophilic macromolecules with stearate- or polyethylene glycol-modified arginine-rich peptide

Recently, nose-to-brain delivery is a highly versatile route, which, in combination with novel drugs being developed for treating intractable CNS diseases, is a promising approach for the treatment of disorders. Furthermore, nano-sized drug carriers may improve nose-to-brain drug delivery by their capability to increase the transmucosal penetration of the drugs across nasal mucosal tissue barrier. However, there is still not enough information regarding mechanism of absorption pathway from nasal cavity to brain using nanocarriers. In this study, to investigate the nose-to-brain transport pathway using nanocarriers, the distribution in whole brain, nasal mucosa, and trigeminal nerve after intranasal administration of two kinds of nanocarriers which have hydrophobic or hydrophilic moiety. We used CHHRRRRHHC peptide (CH2R4H2C) as basic peptide carriers, and modified with stearic acid (STR) as a hydrophobic moiety (STR-CH2R4H2C) or polyethylene glycol (PEG)-based block copolymer (PEG-PCL) as hydrophilic moiety (PEG-PCL-CH2R4H2C). The nose-to-brain drug delivery can be improved by using STR-CH2R4H2C and PEG-PCL-CH2R4H2C as carriers. Specifically, hydrophobic STR-CH2R4H2C is more suitable for the transport of drugs targeting the forebrain, while PEG-PCL-modified CH2R4H2C is more suitable for transporting drugs targeting the hindbrain or whole brain tissue. In conclusion, the results of this study support the possibility that drug delivery pathways can be controlled depending on the properties of different carrier complexes.

Charge convertibility and near infrared photon co-enhanced cisplatin chemotherapy based on upconversion nanoplatform

Optimal nano-sized drug carrier requires long blood circulation, selective extravasation, and efficient cell uptake. Here we develop a charge-convertible nanoplatform based on Pt(IV) prodrug loaded NaYF4:Yb,Tm upconversion nanoparticles (UCNs), followed by coating a layer of PEG-PAH-DMMA polymer (UCNs-Pt(IV)@PEG-PAH-DMMA). The polymer endows the platform with high biocompatibility, initial nano-size for prolonged blood circulation and selective extravasation. Especially, the anionic polymer can response to the mild acidic stimulus (pH ∼6.5) of tumor extracellular microenvironment and experience charge-shifting to a cationic polymer, resulting in electrostatic repulsion and releases of positive UCNs-Pt(IV). The positive UCNs-Pt(IV) nanoparticles have high affinity to negative cell membrane, leading to efficacious cell internalization. Simultaneously, the ultraviolet (UV) light emitted from UCNs upon near-infrared (NIR) light irradiation, together with the reductive glutathione (GSH) in cancer cells efficiently activate the Pt(IV) prodrug to highly cytotoxic Pt(II), realizing NIR photon improved chemotherapy. The experimental results reveal the charge convertibility, low adverse effect and markedly enhanced tumor ablation efficacy upon NIR laser irradiation of this smart nanoplatform. Moreover, combining the inherent upconversion luminescence (UCL) and computed tomography (CT) imaging capabilities, an alliance of cancer diagnosis and therapy has been achieved.