Biocompatible Mesoporous and Soft Nanoarchitectures

Exploring and Analyzing the Systemic Delivery Barriers for Nanoparticles

Most nanomedicines require efficient in vivo delivery to elicit diagnostic and therapeutic effects. However, en route to their intended tissues, systemically administered nanoparticles often encounter delivery barriers. To describe these barriers, we propose the term "nanoparticle blood removal pathways" (NBRP), which summarizes the interactions between nanoparticles and the body's various cell-dependent and cell-independent blood clearance mechanisms. We reviewed nanoparticle design and biological modulation strategies to mitigate nanoparticle-NBRP interactions. As these interactions affect nanoparticle delivery, we studied the preclinical literature from 2011-2021 and analyzed nanoparticle blood circulation and organ biodistribution data. Our findings revealed that nanoparticle surface chemistry affected the in vivo behavior more than other nanoparticle design parameters. Combinatory biological-PEG surface modification improved the blood area under the curve by ~418%, with a decrease in liver accumulation of up to 47%. A greater understanding of nanoparticle-NBRP interactions and associated delivery trends will provide new nanoparticle design and biological modulation strategies for safer, more effective, and more efficient nanomedicines.

Size-Dependent In Vivo Transport of Nanoparticles: Implications for Delivery, Targeting, and Clearance

Understanding the in vivo transport of nanoparticles provides guidelines for designing nanomedicines with higher efficacy and fewer side effects. Among many factors, the size of nanoparticles plays a key role in controlling their in vivo transport behaviors due to the existence of various physiological size thresholds within the body and size-dependent nano-bio interactions. Encouraged by the evolving discoveries of nanoparticle-size-dependent biological effects, we believe that it is necessary to systematically summarize the size-scaling laws of nanoparticle transport in vivo. In this review, we summarized the size effect of nanoparticles on their in vivo transport along their journey in the body: begin with the administration of nanoparticles via different delivery routes, followed by the targeting of nanoparticles to intended tissues including tumors and other organs, and eventually clearance of nanoparticles through the liver or kidneys. We outlined the tools for investigating the in vivo transport of nanoparticles as well. Finally, we discussed how we may leverage the size-dependent transport to tackle some of the key challenges in nanomedicine translation and also raised important size-related questions that remain to be answered in the future.

Hidden symmetry of the flavivirus protein shell and pH-controlled reconstruction of the viral surface

Using recent Zika virus structural data we reveal a hidden symmetry of protein order in immature and mature flavivirus shells, violating the Caspar-Klug paradigmatic model of capsid structures. We show that proteins of the outer immature shell layer exhibit trihexagonal tiling, while proteins from inner and outer layers conjointly form a double-shelled close-packed structure, based on a common triangular spherical lattice. Within the proposed structural model, we furthermore rationalize the structural organization of misassembled non-infectious subviral particles that have no inner capsid. We consider a pH-controlled structural reconstruction of the outer shell from the trimeric to the dimeric state, and demonstrate that this transition, occurring during the virus maturation, can be induced by changes in protein charges at lower pH, leading to a decrease in the electrostatic interaction free energy. This transition could also be assisted by electrostatic attraction of shell proteins to the interposed lipid membrane substrate separating the shells.

Single-Walled Carbon Nanotube-Assisted Antibiotic Delivery and Imaging in S. epidermidis Strains Addressing Antibiotic Resistance

Although conventional antibiotics have evolved as a staple of modern medicine, increasing antibiotic resistance and the lack of antibiotic efficacy against new bacterial threats is becoming a major medical threat. In this work, we employ single-walled carbon nanotubes (SWCNTs) known to deliver and track therapeutics in mammalian cells via intrinsic near-infrared fluorescence as carriers enhancing antibacterial delivery of doxycycline and methicillin. SWCNTs dispersed in water by antibiotics without the use of toxic bile salt surfactants facilitate efficacy enhancement for both antibiotics against Staphylococcus epidermidis strain showing minimal sensitivity to methicillin. Doxycycline to which the strain did not show resistance in complex with SWCNTs provides only minor increase in efficacy, whereas the SWCNTs/methicillin complex yields up to 40-fold efficacy enhancement over antibiotics alone, suggesting that SWCNT-assisted delivery may circumvent antibiotic resistance in that bacterial strain. At the same time SWCNT/antibiotic formulations appear to be less toxic to mammalian cells than antibiotics alone suggesting that nanomaterial platforms may not restrict potential biomedical applications. The improvement in antibacterial performance with SWCNT delivery is tested via 3 independent assays-colony count, MIC (Minimal Inhibitory Concentration) turbidity and disk diffusion, with the statistical significance of the latter verified by ANOVA and Dunnett's method. The potential mechanism of action is attributed to SWCNT interactions with bacterial cell wall and adherence to the membrane, as substantial association of SWCNT with bacteria is observed-the near-infrared fluorescence microscopy of treated bacteria shows localization of SWCNT fluorescence in bacterial clusters, scanning electron microscopy verifies SWCNT association with bacterial surface, whereas transmission electron microscopy shows individual SWCNT penetration into bacterial cell wall. This work characterizes SWCNTs as novel advantageous antibiotic delivery/imaging agents having the potential to address antibiotic resistance.

Cubic Liquid Crystalline Nanostructures Involving Catalase and Curcumin: BioSAXS Study and Catalase Peroxidatic Function after Cubosomal Nanoparticle Treatment of Differentiated SH-SY5Y Cells

The development of nanomedicines for the treatment of neurodegenerative disorders demands innovative nanoarchitectures for combined loading of multiple neuroprotective compounds. We report dual-drug loaded monoolein-based liquid crystalline architectures designed for the encapsulation of a therapeutic protein and a small molecule antioxidant. Catalase (CAT) is chosen as a metalloprotein, which provides enzymatic defense against oxidative stress caused by reactive oxygen species (ROS) such as hydrogen peroxide (H2O2). Curcumin (CU), solubilized in fish oil, is co-encapsulated as a chosen drug with multiple therapeutic activities, which may favor neuro-regeneration. The prepared self-assembled biomolecular nanoarchitectures are characterized by biological synchrotron small-angle X-ray scattering (BioSAXS) at multiple compositions of the lipid/co-lipid/water phase diagram. Constant fractions of curcumin (an antioxidant) and a PEGylated agent (TPEG1000) are included with regard to the lipid fraction. Stable cubosome architectures are obtained for several ratios of the lipid ingredients monoolein (MO) and fish oil (FO). The impact of catalase on the structural organization of the cubosome nanocarriers is revealed by the variations of the cubic lattice parameters deduced by BioSAXS. The outcome of the cellular uptake of the dual drug-loaded nanocarriers is assessed by performing a bioassay of catalase peroxidatic activity in lysates of nanoparticle-treated differentiated SH-SY5Y human cells. The obtained results reveal the neuroprotective potential of the in vitro studied cubosomes in terms of enhanced peroxidatic activity of the catalase enzyme, which enables the inhibition of H2O2 accumulation in degenerating neuronal cells.

Construction and Characterization of a Novel Sustained-Release Delivery System for Hydrophobic Pesticides Using Biodegradable Polydopamine-Based Microcapsules

Microcapsule formulations have been highly desirable and widely developed for effective utilization of pesticides and environmental pollution reduction. However, commercial and traditional microcapsule formulations of λ-cyhalothrin (LC) were prepared by complicated synthesis procedures and thereby specific organic solvents were needed. In this work, LC was encapsulated into versatile, robust, and biodegradable polydopamine (PDA) microcapsules by self-polymerization of dopamine. LC-loaded PDA microcapsules were characterized by transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and thermogravimetric analysis measurements (TGA). LC-loaded PDA microcapsules have uniform morphology with nanoscale, decent LC loading content (>50.0% w/w), and good physicochemical stability and sustained release properties. The bioassay against housefly ( Musca domestica) showed that the bioactivity and long-term efficiency of LC-loaded PDA microcapsules was superior to that of the commercial formulation. All of these results demonstrated that LC-loaded PDA microcapsules could be applied as a commercial LC microcapsule formulation with fewer environmental side effects and higher effective delivery.

Chemistry and engineering of cyclodextrins for molecular imaging

Cyclodextrins (CDs) are naturally occurring cyclic oligosaccharides bearing a basket-shaped topology with an "inner-outer" amphiphilic character. The abundance of hydroxyl groups enables CDs to be functionalized with multiple targeting ligands and imaging elements. The imaging time, and the payload of different imaging elements, can be tuned by taking advantage of the commercial availability of CDs with different sizes of the cavity. This review aims to offer an outlook of the chemistry and engineering of CDs for the development of molecular probes. Complexation thermodynamics of CDs, and the corresponding implications for probe design, are also presented with examples demonstrating the structural and physiochemical roles played by CDs in the full ambit of molecular imaging. We hope that this review not only offers a synopsis of the current development of CD-based molecular probes, but can also facilitate translation of the incremental advancements from the laboratory to real biomedical applications by illuminating opportunities and challenges for future research.

Liquid Crystalline Nanostructures as PEGylated Reservoirs of Omega-3 Polyunsaturated Fatty Acids: Structural Insights toward Delivery Formulations against Neurodegenerative Disorders

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) are bioactive lipids with considerable impact in medicine and nutrition. These compounds exert structuring effects on the cellular membrane organization, regulate the gene expression, and modulate various signaling cascades and metabolic processes. The purpose of the present work is to demonstrate the structural features of ω-3 PUFA-containing three-dimensional supramolecular lipid assemblies suitable for pharmaceutical applications that require soft porous carriers. We investigate the liquid crystalline structures formed upon mixing of eicosapentaenoic acid (EPA, 20:5) with the lyotropic nonlamellar lipid monoolein and the formation of multicompartment assemblies. Starting with the monoolein-based lipid cubic phase, double membrane vesicles, cubosome precursors, sponge-type particles (spongosomes), mixed intermediate nonlamellar structures, and multicompartment assemblies are obtained through self-assembly at different amphiphilic compositions. The dispersions containing spongosomes as well as nanocarriers with oil and vesicular compartments are stabilized by PEGylation of the lipid/water interfaces using a phospholipid with a poly(ethylene glycol) chain. The microstructures of the bulk mixtures were examined by cross-polarized light optical microscopy. The dispersed liquid crystalline structures and intermediate states were studied by small-angle X-ray scattering, cryogenic transmission electron microscopy, and quasielastic light scattering techniques. They established that PUFA influences the phase type and the sizes of the aqueous compartments of the liquid crystalline carriers. The resulting multicompartment systems and stealth nanosponges may serve as mesoporous reservoirs for coencapsulation of ω-3 PUFA (e.g., EPA) with water-insoluble drugs and hydrophilic macromolecules toward development of combination treatment strategies of neurodegenerative and other diseases.

Lyotropic liquid crystal engineering moving beyond binary compositional space - ordered nanostructured amphiphile self-assembly materials by design

Ordered amphiphile self-assembly materials with a tunable three-dimensional (3D) nanostructure are of fundamental interest, and crucial for progressing several biological and biomedical applications, including in meso membrane protein crystallization, as drug and medical contrast agent delivery vehicles, and as biosensors and biofuel cells. In binary systems consisting of an amphiphile and a solvent, the ability to tune the 3D cubic phase nanostructure, lipid bilayer properties and the lipid mesophase is limited. A move beyond the binary compositional space is therefore required for efficient engineering of the required material properties. In this critical review, the phase transitions upon encapsulation of more than 130 amphiphilic and soluble additives into the bicontinuous lipidic cubic phase under excess hydration are summarized. The data are interpreted using geometric considerations, interfacial curvature, electrostatic interactions, partition coefficients and miscibility of the alkyl chains. The obtained lyotropic liquid crystal engineering design rules can be used to enhance the formulation of self-assembly materials and provides a large library of these materials for use in biomedical applications (242 references).

Fabrication of surfactant-stabilized nanosuspension of naringenin to surpass its poor physiochemical properties and low oral bioavailability

BACKGROUND

Nanosuspension is a biphasic system consisting of native drug particles dispersed in an aqueous surfactant or polymeric solution with a particle size between 10 to 1000 nm. In contrast to other drug delivery systems, nanosuspension offer the unique advantage of increasing solubility of the native drug resulting into faster drug absorption and hence achieving faster maximum plasma concentration.

HYPOTHESIS/PURPOSE

The present study aims to evaluate surfactants/polymer stabilized nanosuspensions of naringenin (NN), a phytomedicine, to surpass its poor physiochemical properties and low oral bioavailability.

STUDY DESIGN

Optimization and characterization (DLS, SEM, PXRD and DSC) of nanosuspensions followed by in-vitro drug dissolution studies and pharmacokinetic study in male Sprague-Dawley rats were performed.

METHODS

Nanosuspensions were prepared by precipitation-ultrasonication method with varying concentrations of different surfactants and polymer such as sodium cholate (SC), sodium lauryl sulphate (SLS), poly ethylene glycol 4000 (PEG), polysorbate 80 (Tween^® 80), poloxomer-188 and D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS or Vitamin E-TPGS).

RESULTS

Nanosuspension prepared with 0.5% w/v d-α-Tocopherol polyethylene glycol 1000 succinate (TPNS) and 7.5 mg NN, showed the smallest size of 118.1 ± 2.7 nm. TPNS showed increase in drug dissolution in simulated gastric fluid pH 1.2 (SGF) and phosphate buffer pH 6.8 (PB). TPNS demonstrated an improved pharmacokinetic profile compared to pure NN resulting 2.14 and 3.76 folds increase in C_max and AUC, respectively. In addition, TPNS were stable over a period of six months.

CONCLUSION

The developed formulation strategy of nanosuspension could be exploited to improve the solubility and bio-availability of poorly soluble NN and other phytomedicines.

Liquid-crystalline nanoarchitectures for tissue engineering

Hierarchical orders are found throughout all levels of biosystems, from simple biopolymers, subcellular organelles, single cells, and macroscopic tissues to bulky organs. Especially, biological tissues and cells have long been known to exhibit liquid crystal (LC) orders or their structural analogues. Inspired by those native architectures, there has recently been increased interest in research for engineering nanobiomaterials by incorporating LC templates and scaffolds. In this review, we introduce and correlate diverse LC nanoarchitectures with their biological functionalities, in the context of tissue engineering applications. In particular, the tissue-mimicking LC materials with different LC phases and the regenerative potential of hard and soft tissues are summarized. In addition, the multifaceted aspects of LC architectures for developing tissue-engineered products are envisaged. Lastly, a perspective on the opportunities and challenges for applying LC nanoarchitectures in tissue engineering fields is discussed.

Advances in structural design of lipid-based nanoparticle carriers for delivery of macromolecular drugs, phytochemicals and anti-tumor agents

The present work highlights recent achievements in development of nanostructured dispersions and biocolloids for drug delivery applications. We emphasize the key role of biological small-angle X-ray scattering (BioSAXS) investigations for the nanomedicine design. A focus is given on controlled encapsulation of small molecular weight phytochemical drugs in lipid-based nanocarriers as well as on encapsulation of macromolecular siRNA, plasmid DNA, peptide and protein pharmaceuticals in nanostructured nanoparticles that may provide efficient intracellular delivery and triggered drug release. Selected examples of utilisation of the BioSAXS method for characterization of various types of liquid crystalline nanoorganizations (liposome, spongosome, cubosome, hexosome, and nanostructured lipid carriers) are discussed in view of the successful encapsulation and protection of phytochemicals and therapeutic biomolecules in the hydrophobic or the hydrophilic compartments of the nanocarriers. We conclude that the structural design of the nanoparticulate carriers is of crucial importance for the therapeutic outcome and the triggered drug release from biocolloids.

Self-Assembled Lipid Cubic Phase and Cubosomes for the Delivery of Aspirin as a Model Drug

Three-dimensionally organized lipid cubic self-assemblies and derived oil-in-water emulsions called "cubosomes" are attractive for various biotechnological applications due to their ability to be loaded with functional molecules and their associated sustained release properties. Here, we employed both of these lipid-based systems for the delivery of a model drug, aspirin, under comparable conditions. Studies were performed by varying drug-to-lipid ratio and the type of release medium, water and phosphate buffer saline (PBS). Release rates were determined using UV-vis spectroscopy, and small-angle X-ray scattering was used to confirm the type of self-assembled nanostructures formed in these lipid systems. The release from the bulk lipid cubic phase was sustained as compared to that of dispersed cubosomes, and the release in PBS was more efficient than in water. The tortuosity of the architecture, length of the diffusion pathway, type of nanostructure, and physicochemical interaction with the release media evidently contribute to these observations. This work is particularly important as it is the first report where both of these nanostructured lipid systems have been studied together under similar conditions. This work provides important insights into understanding and therefore controlling the release behavior of lipid-based drug nanocarriers.

DNA nanostructure-based drug delivery nanosystems in cancer therapy

DNA as a novel biomaterial can be used to fabricate different kinds of DNA nanostructures based on its principle of GC/AT complementary base pairing. Studies have shown that DNA nanostructure is a nice drug carrier to overcome big obstacles existing in cancer therapy such as systemic toxicity and unsatisfied drug efficacy. Thus, different types of DNA nanostructure-based drug delivery nanosystems have been designed in cancer therapy. To improve treating efficacy, they are also developed into more functional drug delivery nanosystems. In recent years, some important progresses have been made. The objective of this review is to make a retrospect and summary about these different kinds of DNA nanostructure-based drug delivery nanosystems and their latest progresses: (1) active targeting; (2) mutidrug co-delivery; (3) construction of stimuli-responsive/intelligent nanosystems.

Multilayer gyroid cubic membrane organization in green alga Zygnema

Biological cubic membranes (CM), which are fluid membranes draped onto the 3D periodic parallel surface geometries with cubic symmetry, have been observed within subcellular organelles, including mitochondria, endoplasmic reticulum, and thylakoids. CM transition tends to occur under various stress conditions; however, multilayer CM organizations often appear associated with light stress conditions. This report is about the characterization of a projected gyroid CM in a transmission electron microscopy study of the chloroplast membranes within green alga Zygnema (LB923) whose lamellar form of thylakoid membrane started to fold into multilayer gyroid CM in the culture at the end of log phase of cell growth. Using the techniques of computer simulation of transmission electron microscopy (TEM) and a direct template matching method, we show that these CM are based on the gyroid parallel surfaces. The single, double, and multilayer gyroid CM morphologies are observed in which space is continuously divided into two, three, and more subvolumes by either one, two, or several parallel membranes. The gyroid CM are continuous with varying amount of pseudo-grana with lamellar-like morphology. The relative amount and order of these two membrane morphologies seem to vary with the age of cell culture and are insensitive to ambient light condition. In addition, thylakoid gyroid CM continuously interpenetrates the pyrenoid body through stalk, bundle-like, morphologies. Inside the pyrenoid body, the membranes re-folded into gyroid CM. The appearance of these CM rearrangements due to the consequence of Zygnema cell response to various types of environmental stresses will be discussed. These stresses include nutrient limitation, temperature fluctuation, and ultraviolet (UV) exposure.

The effect of solution pH on the structural stability of magnetoferritin

The structural stability of magnetoferritin, a synthetic analogue of ferritin, at various pH levels is assessed here. The structural and electrical properties of the complexes were determined by small-angle X-ray scattering (SAXS), dynamic light scattering (DLS) and zeta potential measurements. At pH 3-6 a reduction of electrostatic repulsion on the suspended colloids resulted in aggregation and sedimentation of magnetoferritin. At neutral to slightly alkaline conditions (pH 7-9) the magnetoferritin structure was stable for lower iron loadings. Higher solution pH 10-12 induced destabilization of the protein structure and dissociation of subunits. Increasing the loading factor in the MFer complex leads to decrease of the stability versus pH changes.

Dehydrobruceine B enhances the cisplatin-induced cytotoxicity through regulation of the mitochondrial apoptotic pathway in lung cancer A549 cells

Dehydrobruceine B (DHB) is a quassinoid isolated from Brucea javanica. We have shown previously that DHB induced apoptosis on two kinds of lung cancer cell lines, A549 and NCI-H292. In the present study, we investigated the interactions of DHB and cisplatin (CDDP) on apoptotic-related cancer cell death. Synergistic effects on cell proliferation and apoptosis were observed when A549 cells were treated with DHB plus CDDP. DHB combined CDDP exposure increased depolarization of mitochondrial membrane potential (MMP) and release of cytochrome c from mitochondria into the cytoplasm. The combination treatment also enhanced protein expression of Bax, reduced the protein levels of Bcl-xL and Bcl-2, and increased the cleavage of caspase-3, caspase-9 and poly (ADP-ribose) polymerase (PARP). These results indicated that DHB sensitized A549 cells to cisplatin by regulating the mitochondrial apoptotic pathway. High constitutive expression of Nrf2 was found in A549 cells, which enhance the resistance of cancer cells to chemotherapeutic agents including cisplatin. DHB reduced the protein levels of Nrf2 and its target genes, which may contribute to the increase of intracellular ROS level, consequently, induced mitochondria apoptosis. These results generated a rationale for further investigation of DHB combined with CDDP as a potential therapeutic strategy in lung cancer.

Self-assembled stable sponge-type nanocarries for Brucea javanica oil delivery

Sponge-type nanocarriers (spongosomes) are produced upon dispersion of a liquid crystalline sponge phase formed by self-assembly of an amphiphilic lipid in excess aqueous phase. The inner organization of the spongosomes is built-up by randomly ordered bicontinuous lipid membranes and their surfaces are stabilized by alginate chains providing stealth properties and colloidal stability. The present study elaborates spongosomes for improved encapsulation of Brucea javanica oil (BJO), a traditional Chinese medicine that may strongly inhibit proliferation and metastasis of various cancers. The inner structural organization and the morphology characteristics of BJO-loaded nanocarriers at varying quantities of BJO were determined by cryogenic transmission electron microscopy (Cryo-TEM), small angle X-ray scattering (SAXS) and dynamic light scattering (DLS). Additionally, the drug loading and drug release profiles for BJO-loaded spongosome systems also were determined. We found that the sponge-type liquid crystalline lipid membrane organization provides encapsulation efficiency rate of BJO as high as 90%. In vitro cytotoxicity and apoptosis study of BJO spongosome nanoparticles with A549 cells demonstrated enhanced anti-tumor efficiency. These results suggest potential clinical applications of the obtained safe spongosome formulations.

Overcoming Immune Dysregulation with Immunoengineered Nanobiomaterials

The immune system is governed by an immensely complex network of cells and both intracellular and extracellular molecular factors. It must respond to an ever-growing number of biochemical and biophysical inputs by eliciting appropriate and specific responses in order to maintain homeostasis. But as with any complex system, a plethora of false positives and false negatives can occur to generate dysregulated responses. Dysregulated immune responses are essential components of diverse inflammation-driven pathologies, including cancer, heart disease, and autoimmune disorders. Nanoscale biomaterials (i.e., nanobiomaterials) have emerged as highly customizable platforms that can be engineered to interact with and direct immune responses, holding potential for the design of novel and targeted approaches to redirect or inhibit inflammation. Here, we present recent developments of nanobiomaterials that were rationally designed to target and modulate inflammatory cells and biochemical pathways for the treatment of immune dysregulation.

Nano-encapsulation of a novel anti-Ran-GTPase peptide for blockade of regulator of chromosome condensation 1 (RCC1) function in MDA-MB-231 breast cancer cells

Ran is a small ras-related GTPase and is highly expressed in aggressive breast carcinoma. Overexpression induces malignant transformation and drives metastatic growth. We have designed a novel series of anti-Ran-GTPase peptides, which prevents Ran hydrolysis and activation, and although they display effectiveness in silico, peptide activity is suboptimal in vitro due to reduced bioavailability and poor delivery. To overcome this drawback, we delivered an anti-Ran-GTPase peptide using encapsulation in PLGA-based nanoparticles (NP). Formulation variables within a double emulsion solvent evaporation technique were controlled to optimise physicochemical properties. NP were spherical and negatively charged with a mean diameter of 182-277nm. Peptide integrity and stability were maintained after encapsulation and release kinetics followed a sustained profile. We were interested in the relationship between cellular uptake and poly(ethylene glycol) (PEG) in the NP matrix, with results showing enhanced in vitro uptake with increasing PEG content. Peptide-loaded, pegylated (10% PEG)-PLGA NP induced significant cytotoxic and apoptotic effects in MDA-MB-231 breast cancer cells, with no evidence of similar effects in cells pulsed with free peptide. Western blot analysis showed that encapsulated peptide interfered with the proposed signal transduction pathway of the Ran gene. Our novel blockade peptide prevented Ran activation by blockage of regulator of chromosome condensation 1 (RCC1) following peptide release directly in the cytoplasm once endocytosis of the peptide-loaded nanoparticle has occurred. RCC1 blockage was effective only when a nanoparticulate delivery approach was adopted.

Theranostic hexosomes for cancer treatments: an in vitro study

Targeted liquid crystalline nanoparticles with a reverse hexagonal inner structure as diagnostic and therapeutic tools in oncology.

Spectroscopic investigation of bio-mimetic solvolysis of 6-(N,N-dimethylamino)-2,3-naphthalic anhydride in confined nanocavities

Enzymes are biological catalysts that can vastly accelerate the reaction rate of a substrate by accommodating it within the active site.

Dual and multi-drug delivery nanoparticles towards neuronal survival and synaptic repair

Among the macromolecular drug targets in neurodegenerative disorders, the neurotrophin brain-derived neurotrophic factor (BDNF) and its high-affinity tropomyosin-related kinase receptor (TrkB) present strong interest for nanomedicine development aiming at neuronal and synaptic repair. Currently, BDNF is regarded as the neurotrophic factor of highest therapeutic significance. However, BDNF has delivery problems as a protein drug. The enhanced activation of the transcription factor CREB (cAMP response element-binding protein) has been evidenced to increase the BDNF gene expression and hence the production of endogenous BDNF. We assume that BDNF delivery by nanocarriers and mitochondrial protection may provide high potential for therapeutic amelioration of the neuroregenerative strategies. Beneficial therapeutic outcomes may be expected for synergistic dual or multi-drug action aiming at (i) neurotrophic protein regulation in the central and peripheral nervous systems, and (ii) diminishment of the production of reactive oxygen species (ROS) and the oxidative damage in mitochondria. Our research strategy is based on a nanoarchitectonics approach for the design of nanomedicine assemblies by hierarchical self-assembly. We explore nanoarchitectonics concepts in soft-matter nanotechnology towards preparation of biodegradable self-assembled lipid nanostructures for safe neuro-therapeutic applications of multi-target nanomedicines.

In Vitro Modulation of TrkB Receptor Signaling upon Sequential Delivery of Curcumin-DHA Loaded Carriers Towards Promoting Neuronal Survival

PURPOSE

To in vitro investigate the capacity of carrier-free and lipid-nanoparticle (NP)-encapsulated phytochemical compounds to prevent neuronal damage through neurotrophin potentiating activities. Delivery of molecules promoting the neurotrophin receptor signaling in the central nervous system (CNS) present ongoing interest for combination therapy development.

METHODS

Super-resolution Stimulated Emission Depletion (STED) microscopy imaging and flow cytometry analysis were employed to study the expression of the neurotrophin TrkB receptor in a neuronal cell model, which is highly responsive to binding of brain-derived neurotrophic factor (BDNF). Dual drug-loaded nanoparticle formulations, prepared by self-assembly of lyotropic lipids and PEGylated amphiphile derivatives, were delivered to differentiated human neuroblastoma SH-SY5Y cells subjected to degenerative conditions.

RESULTS

The expression of BDNF in the intra and extracellular domains was quantified by ELISA and flow cytometry after sequential treatment of the degenerating SH-SY5Y cells by neurotherapeutic formulations. Flow cytometry was also used to assess the phosphorylation of the transcription factor cAMP response element-binding protein (CREB) in the intracellular domain as a result of the treatment by nanoformulations.

CONCLUSION

Over time, dual drug formulations (curcumin and docosahexaenoic acid (DHA)) promoted the neuronal survival and repair processes through enhanced BDNF secretion and increased phosphorylation of CREB as compared to untreated degenerating cells.

Mesoporous self-assembled nanoparticles of biotransesterified cyclodextrins and nonlamellar lipids as carriers of water-insoluble substances

Soft mesoporous hierarchically structured particles were created by the self-assembly of an amphiphilic deep cavitand cyclodextrin βCD-nC₁₀ (degree of substitution n = 7.3), with a nanocavity grafted by multiple alkyl (C₁₀) chains on the secondary face of the βCD macrocycle through enzymatic biotransesterification, and the nonlamellar lipid monoolein (MO). The effect of the non-ionic dispersing agent polysorbate 80 (P80) on the liquid crystalline organization of the nanocarriers and their stability was studied in the context of vesicle-to-cubosome transition. The coexistence of small vesicular and nanosponge membrane objects with bigger nanoparticles with inner multicompartment cubic lattice structures was established as a typical feature of the employed dispersion process. The cryogenic transmission electron microscopy (cryo-TEM) images and small-angle X-ray scattering (SAXS) structural analyses revealed the dependence of the internal organization of the self-assembled nanoparticles on the presence of embedded βCD-nC₁₀ deep cavitands in the lipid bilayers. The obtained results indicated that the incorporated amphiphilic βCD-nC₁₀ building blocks stabilize the cubic lattice packing in the lipid membrane particles, which displayed structural features beyond the traditional CD nanosponges. UV-Vis spectroscopy was employed to characterize the nanoencapsulation of a model hydrophobic dimethylphenylazo-naphthol guest compound (Oil red) in the created nanocarriers. In perspective, these dual porosity carriers should be suitable for co-encapsulation and sustained delivery of peptide, protein or siRNA biopharmaceuticals together with small molecular weight drug compounds or imaging agents.

Effect of fullerene on the dispersibility of nanostructured lipid particles and encapsulation in sterically stabilized emulsions

We report on the effect of fullerenes (C60) on the stability of nanostructured lipid emulsions. These (oil-in-water) emulsions are essentially aqueous dispersions of lipid particles exhibiting self-assembled nanostructures at their cores. The majority of previous studies on fullerenes were focused on planar and spherical lipid bilayer systems including pure lipids and liposomes. In this work, fullerenes were interacted with a lipid that forms nanostructured dispersions of non-lamellar self-assemblies. A range of parameters including the composition of emulsions and sonication parameters were examined to determine the influence of fullerenes on in-situ and pre-stabilized lipid emulsions. We found that fullerenes mutually stabilize very low concentrations of lipid molecules, while other concentration emulsions struggle to stay stable or even to form at first instance; we provide hypotheses to support these observations. Interestingly though, we were able to encapsulate varying amounts of fullerenes in sterically stabilized emulsions. This step has a significant positive impact, as we could effectively control an inherent aggregation tendency of fullerenes in aqueous environments. These novel hybrid nanomaterials may open a range of avenues for biotechnological and biomedical applications exploiting properties of both lipid and fullerene nanostructures.

Reductively Responsive Hydrogel Nanoparticles with Uniform Size, Shape, and Tunable Composition for Systemic siRNA Delivery in Vivo

To achieve the great potential of siRNA based gene therapy, safe and efficient systemic delivery in vivo is essential. Here we report reductively responsive hydrogel nanoparticles with highly uniform size and shape for systemic siRNA delivery in vivo. "Blank" hydrogel nanoparticles with high aspect ratio were prepared using continuous particle fabrication based on PRINT (particle replication in nonwetting templates). Subsequently, siRNA was conjugated to "blank" nanoparticles via a disulfide linker with a high loading ratio of up to 18 wt %, followed by surface modification to enhance transfection. This fabrication process could be easily scaled up to prepare large quantity of hydrogel nanoparticles. By controlling hydrogel composition, surface modification, and siRNA loading ratio, siRNA conjugated nanoparticles were highly tunable to achieve high transfection efficiency in vitro. FVII-siRNA conjugated nanoparticles were further stabilized with surface coating for in vivo siRNA delivery to liver hepatocytes, and successful gene silencing was demonstrated at both mRNA and protein levels.

Identification of large channels in cationic PEGylated cubosome nanoparticles by synchrotron radiation SAXS and Cryo-TEM imaging

Extra-large nanochannel formation in the internal structure of cationic cubosome nanoparticles results from the interplay between charge repulsion and steric stabilization of the lipid membrane interfaces and is evidenced by cryogenic transmission electron microscopy (Cryo-TEM) and synchrotron radiation small-angle X-ray scattering (SAXS). The swollen cubic symmetry of the lipid nanoparticles emerges through a shaping transition of onion bilayer vesicle intermediates containing a fusogenic nonlamellar lipid. Cationic amphiphile cubosome particles, thanks to the advantages of their liquid crystalline soft porous nanoarchitecture and capability for multi-drug nanoencapsulation, appear to be of interest for the design of mitochondrial targeting devices in anti-cancer therapies and as siRNA nanocarriers for gene silencing.

Sterically stabilized spongosomes for multidrug delivery of anticancer nanomedicines

SAXS patterns of drug-loaded lipid nanocarriers stabilized by polysorbate P80 (left); cryo-TEM image of BAI-BJO-spongosomes-2 (right).