Gene delivery based on macrocyclic amphiphiles

β-Cyclodextrin-based geometrically frustrated amphiphiles as one-component, cell-specific and organ-specific nucleic acid delivery systems

We introduce an innovative β-cyclodextrin (βCD)-prototype for delivering nucleic acids: "geometrically frustrated amphiphiles (GFAs)." GFAs are designed with cationic centers evenly distributed across the primary O6 and secondary O2 positions of the βCD scaffold, while hydrophobic tails are anchored at the seven O3 positions. Such distribution of functional elements differs from Janus-type architectures and enlarges the capacity for accessing strictly monodisperse variants. Changes at the molecular level can then be correlated with preferred self-assembly and plasmid DNA (pDNA) co-assembly behaviors. Specifically, GFAs undergo pH-dependent transition between bilayered to monolayered vesicles or individual molecules. GFA-pDNA nanocomplexes exhibit topological and internal order characteristics that are also a function of the GFA molecular architecture. Notably, adjusting the pKa of the cationic heads and the hydrophilic-hydrophobic balance, pupa-like arrangements implying axial alignments of GFA units flanked by quasi-parallel pDNA segments are preferred. In vitro cell transfection studies revealed remarkable differences in relative performances, which corresponded to distinct organ targeting outcomes in vivo. This allowed for preferential delivery to the liver and lung, kidney or spleen. The results collectively highlight cyclodextrin-based GFAs as a promising class of molecular vectors capable of finely tuning cell and organ transfection selectivity.

Macrocycle-Based Supramolecular Drug Delivery Systems: A Concise Review

Efficient delivery of therapeutic agents to the lesion site or specific cells is an important way to achieve "toxicity reduction and efficacy enhancement". Macrocycles have always provided many novel ideas for drug or gene loading and delivery processes. Specifically, macrocycles represented by crown ethers, cyclodextrins, cucurbit[n]urils, calix[n]arenes, and pillar[n]arenes have unique properties, which are different cavity structures, good biocompatibility, and good stability. Benefited from these diverse properties, a variety of supramolecular drug delivery systems can be designed and constructed to effectively improve the physical and chemical properties of guest molecules as needed. This review provides an outlook on the current application status and main limitations of macrocycles in supramolecular drug delivery systems.

Emergence of Nanoscale Drug Carriers through Supramolecular Self-Assembly of RNA with Calixarene

Supramolecular self-assembly is a powerful tool for the development of polymolecular assemblies that can form the basis of useful nanomaterials. Given the increasing popularity of RNA therapy, the extension of this concept of self-assembly to RNA is limited. Herein, a simple method for the creation of nanosized particles through the supramolecular self-assembly of RNA with a three-dimensional macrocycle from the calixarene family was reported for the first time. This self-assembly into nanoparticles was realized using cooperative supramolecular interactions under mild conditions. The obtained nanoparticles are able to bind various hydrophobic (quercetin, oleic acid) and hydrophilic (doxorubicin) drugs, as a result of which their cytotoxic properties are enhanced. This work demonstrates that intermolecular interactions between flexible RNA and rigid calixarene is a promising route to bottom-up assembly of novel supramolecular soft matter, expanding the design possibilities of nanoscale drug carriers.

Nanotechnology-enabled gene delivery for cancer and other genetic diseases

INTRODUCTION

Despite gene therapy is ideal for genetic abnormality-related diseases, the easy degradation, poor targeting, and inefficiency in entering targeted cells are plaguing the effective delivery of gene therapy. Viral and non-viral vectors have been used for delivering gene therapeutics in vivo by safeguarding nucleic acid agents to target cells and to reach the specific intracellular location. A variety of nanotechnology-enabled safe and efficient systems have been successfully developed to improve the targeting ability for effective therapeutic delivery of genetic drugs.

AREAS COVERED

In this review, we outline the multiple biological barriers associated with gene delivery process, and highlight recent advances to gene therapy strategy in vivo, including gene correction, gene silencing, gene activation and genome editing. We point out current developments and challenges exist of non-viral and viral vector systems in association with chemical and physical gene delivery technologies and their potential for the future.

EXPERT OPINION

This review focuses on the opportunities and challenges to various gene therapy strategy, with specific emphasis on overcoming the challenges through the development of biocompatibility and smart gene vectors for potential clinical application.

Calix[4]Resorcinarene Carboxybetaines and Carboxybetaine Esters: Synthesis, Investigation of In Vitro Toxicity, Anti-Platelet Effects, Anticoagulant Activity, and BSA Binding Affinities

As a result of bright complexation properties, easy functionalization and the ability to self-organize in an aqueous solution, amphiphilic supramolecular macrocycles are being actively studied for their application in nanomedicine (drug delivery systems, therapeutic and theranostic agents, and others). In this regard, it is important to study their potential toxic effects. Here, the synthesis of amphiphilic calix[4]resorcinarene carboxybetaines and their esters and the study of a number of their microbiological properties are presented: cytotoxic effect on normal and tumor cells and effect on cellular and non-cellular components of blood (hemotoxicity, anti-platelet effect, and anticoagulant activity). Additionally, the interaction of macrocycles with bovine serum albumin as a model plasma protein is estimated by various methods (fluorescence spectroscopy, synchronous fluorescence spectroscopy, circular dichroic spectroscopy, and dynamic light scattering). The results demonstrate the low toxicity of the macrocycles, their anti-platelet effects at the level of acetylsalicylic acid, and weak anticoagulant activity. The study of BSA-macrocycle interactions demonstrates the dependence on macrocycle hydrophilic/hydrophobic group structure; in the case of carboxybetaines, the formation of complexes prevents self-aggregation of BSA molecules in solution. The present study demonstrates new data on potential drug delivery nanosystems based on amphiphilic calix[4]resorcinarenes for their cytotoxicity and effects on blood components.

Calix[4]arene Polyamine Triazoles: Synthesis, Aggregation and DNA Binding

Artificial gene delivery systems are in great demand from both scientific and practical biomedical points of view. In this paper, we present the synthesis of a new click chemistry calix[4]arene precursor with free lower rim and new water-soluble calixarene triazoles with 12 amino-groups on the upper rim (one with free phenol hydroxyl groups and two another containing four butyl or tetradecyl fragments). Aggregation in the series of amino-triazole calixarenes of different lipophilicity (calixarene with free phenol hydroxyl groups or butyl and tetradecyl fragments on the lower rim) was studied using dynamic light scattering and fluorescent pyrene probe. It was found that calix[4]arene with a free lower rim, like alkyl-substituted butyl calix[4]arene, forms stable submicron aggregates 150-200 nm in size, while the more lipophilic tetradecyl -substituted calix[4]arene forms micellar aggregates19 nm in size. Using UV-Vis spectroscopy, fluorimetry and CD, it was shown that amino-triazole calix[4]arenes bind to calf thymus DNA by classical intercalation. According to DLS and TEM data, all studied macrocycles cause significant DNA compaction, forming stable nanoparticles 50-20 nm in size. Among all studied calix[4]arenes the most lipophilic tetradecyl one proved to be the best for both binding and compaction of DNA.

A β-Cyclodextrin-Based Nanoparticle with Very High Transfection Efficiency Unveils siRNA-Activated TLR3 Responses in Human Prostate Cancer Cells

Synthetic double-stranded small interfering RNAs (siRNAs) mimic interference RNAs (RNAi) and can bind target mRNAs with a high degree of specificity, leading to selective knockdown of the proteins they encode. However, siRNAs are very labile and must be both protected and transported by nanoparticles to be efficiently delivered into cells. In this work, we used a Janus-type polycationic amphiphilic β-cyclodextrin derivative to efficiently transfect siRNAs targeting mRNAs encoding mitogen-activated protein kinase (p42-MAPK) or Ras homolog enriched in brain (Rheb) into different cancer cell lines as well as astrocytes. We took advantage of this high transfection efficiency to simultaneously knock down p42-MAPK and Rheb to boost docetaxel (DTX)-mediated toxicity in two human prostate cancer cell lines (LNCaP and PC3). We found that double knockdown of p42-MAPK and Rheb increased DTX-toxicity in LNCaP but not in PC3 cells. However, we also observed the same effect when scramble siRNA was used, therefore pointing to an off-target effect. Indeed, we found that the siRNA we used in this work induced toll-like receptor 3 activation, leading to β-interferon production and caspase activation. We believe that this mechanism could be very useful as a general strategy to elicit an immune response against prostate cancer cells.

Anionic amphiphilic calixarenes for peptide assembly and delivery

Shape-persistent macrocycles enable superior control on molecular self-assembly, allowing the preparation of well-defined nanostructures with new functions. Here, we report on anionic amphiphilic calixarenes of conic shape and their self-assembly behavior in aqueous media for application in intracellular delivery of peptides. Newly synthesized calixarenes bearing four phosphonate groups and two or four long alkyl chains were found to form micelles of ∼ 10 nm diameter, in contrast to an analogue with short alkyl chains. These amphiphilic calixarenes are able to complex model (oligo-lysine) and biologically relevant (HIV-1 nucleocapsid peptide) cationic peptides into small nanoparticles (20-40 nm). By contrast, a control anionic calixarene with short alkyl chains fails to form small nanoparticles with peptides, highlighting the importance of micellar assembly of amphiphilic calixarenes for peptide complexation. Cellular studies reveal that anionic amphiphilic calixarenes exhibit low cytotoxicity and enable internalization of fluorescently labelled peptides into live cells. These findings suggest anionic amphiphilic macrocycles as promising building blocks for the preparation of peptide delivery vehicles.

Red fluorescent AIEgens based multifunctional nonviral gene vectors for the efficient combination of gene therapy and photodynamic therapy in anti-cancer

Precise molecular engineering of AIEgens-based cationic delivery systems for high transfection efficiency (TE) and effective photodynamic therapy (PDT) holds a huge potential for cancer treatment. Herein, three amphiphiles (DT-C_6/8/12-M) consisting of di(triazole-[12]aneN₃) (M) and 1,1-dicyano-2-phenyl-2-(4-diphenylamino)phenyl-ethylene (DT) units have been developed to achieve luminescent tracking, efficient TE, and effective PDT in vitro and in vivo. These compounds exhibited strong aggregated induced emission (AIE) at 630 nm and mega Stokes shifts of up to 160 nm. They were able to bind DNA into nanoparticles with suitable sizes, positive surface potential, and good biocompatibility in the presence of DOPE. Among them, vector DT-C₁₂-M/DOPE with n-dodecyl linker achieved a transfection efficiency as high as 42.3 folds that of Lipo2000 in PC-3 cell lines. DT-C₁₂-M/DOPE exhibited the capability of successful endo/lysosomal escape and rapid nuclear delivery of pDNA, and the gene delivery process was clearly monitored via confocal laser scanning microscopy. Moreover, efficient reactive oxygen species (ROS) generation by DT-C₁₂-M upon light irradiation led to effective PDT in vitro . We further show that combination of p53 gene therapy and PDT dramatically enhanced cancer therapeutic outcome in vivo. This "three birds, one stone" strategy offers a novel and promising approach for real-time tracking of gene delivery and better cancer treatment.

Monitoring Methionine Decarboxylase by Supramolecular Tandem Assay

Methionine is an essential amino acid involved in many physiological and pathological processes. Methionine starvation caused by methionine decarboxylase ( MetDC) degradation becomes a promising strategy for cancer treatment. Multistep colorimetric method, the present approach to monitor the MetDC activity, possesses drawbacks of the complicated process, low accuracy, and poor anti-interference due to indirect detecting. Herein, we report a facile and easy-to-use supramolecular tandem assay (STA) with cucurbit[7]uril and acridine orange reporter pair for the direct and real-time monitoring of MetDC activity. The applicability of this strategy for measuring enzyme-kinetic parameters and screening of inhibitors are also demonstrated. The STA for MetDC activity detection not only provides a feasible method for methionine-related disease diagnosing but also opens a perspective for cancer therapy.

Supramolecular Radiosensitizer Based on Hypoxia-Responsive Macrocycle

Radiotherapy (RT) has been viewed as one of the most effective and extensively applied curatives in clinical cancer therapy. However, the radioresistance of tumor severely discounts the radiotherapy outcomes. Here, an innovative supramolecular radiotherapy strategy, based on the complexation of a hypoxia-responsive macrocycle with small-molecule radiosensitizer, is reported. To exemplify this tactic, a carboxylated azocalix[4]arene (CAC4A) is devised as molecular container to quantitatively package tumor sensitizer banoxantrone dihydrochloride (AQ4N) through reversible host-guest interaction. Benefited from the selective reduction of azo functional groups under hypoxic microenvironment, the supramolecular prodrug CAC4A•AQ4N exhibits high tumor accumulation and efficient cellular internalization, thereby significantly amplifying radiation-mediated tumor destruction without appreciable systemic toxicity. More importantly, this supramolecular radiotherapy strategy achieves an ultrahigh sensitizer enhancement ratio (SER) value of 2.349, which is the supreme among currently reported noncovalent-based radiosensitization approach. Further development by applying different radiosensitizing drugs can make this supramolecular strategy become a general platform for boosting therapeutic effect in cancer radiotherapies, tremendously promising for clinical translation.

Highly effective gene delivery based on cyclodextrin multivalent assembly in target cancer cells

A supramolecular assembly based on cyclodextrins for highly effective gene delivery responded to NIR light and reductase in targeted cancer cells.

Artificial light-harvesting systems based on macrocycle-assisted supramolecular assembly in aqueous media

Light-harvesting, which involves the conversion of sunlight into chemical energy by natural systems such as plants, bacteria, is one of the most universal routine activities in nature. Thus far, various artificial light-harvesting systems (LHSs) have been fabricated toward solar energy utilization through mimicking natural photosynthesis in simplified and altered ways. Macrocycles are supramolecular hosts with unique cavities, in which specific guest molecules can be recognized based on non-covalent interactions. They have been widely employed in constructing LHSs due to their ability to form supramolecular assembly and dynamic molecular activity. In this review, we mainly focus on some representative examples reported by our group and other groups. Specifically, the fabrication of LHSs and their related discussions, such as a high donor/acceptor ratio, driving force for the formation of supramolecular assemblies and energy transfer mechanisms using different water-soluble macrocycles such as cyclodextrins (CD), pillararenes (PA), calixarenes (CA), cucurbiturils (CB), and other macrocycles will be included. In addition, how the resulting supramolecular self-assembled LHSs could be potentially utilized for photocatalysis, sensing, and imaging is also explained in detail. Challenges and developing trends for photochemical solar energy conversion will also be presented.

A Supramolecular Antidote to Macromolecular Toxins Prepared through Coassembly of Macrocyclic Amphiphiles

Poisoning is a leading cause of admission to medical emergency departments and intensive care units. Supramolecular detoxification, which involves injecting supramolecular receptors that bind with toxins to suppress their biological activity, is an emerging strategy for poisoning treatment; it has few requirements and a broad application scope. However, it is still a formidable challenge to design supramolecular therapeutic materials as an antidote to macromolecular toxins, because the large size, flexible conformation, and presence of multiple and diverse binding sites of biomacromolecules hinder their recognition. Herein, a supramolecular antidote to macromolecular toxins is developed through the coassembly of macrocyclic amphiphiles, relying on heteromultivalent recognition between the coassembled components and toxic macromolecules. The coassembly of amphiphilic cyclodextrin and calixarene strongly and selectively captures melittin, a toxin studied herein; this imparts various therapeutic effects such as inhibiting the interactions of melittin with cell membranes, alleviating melittin cytotoxicity and hemolytic toxicity, reducing the mortality rate of melittin-poisoned mice, and mitigating damage to major organs. The use of the proposed antidote overcomes the limitation of supramolecular detoxification applicability to only small-molecular toxins. The antidote can also detoxify other macromolecular toxins as long as selective and strong binding is achieved because of the coassembling tunability.

Supramolecular Bioimaging through Signal Amplification by Combining Indicator Displacement Assay with Förster Resonance Energy Transfer

Fluorescent chemosensors are powerful imaging tools in the fields of life sciences and engineering. Based on the principle of supramolecular chemistry, indicator displacement assay (IDA) provides an alternative approach for constructing and optimizing chemosensors, which has the advantages of simplicity, tunability, and modularity. However, the application of IDA in bioimaging continues to face a series of challenges, including interfering signals, background noise, and inconsistent spatial location. Accordingly, we herein report a supramolecular bioimaging strategy of Förster resonance energy transfer (FRET)-assisted IDA by employing macrocyclic amphiphiles as the operating platform. By merging FRET with IDA, the limitations of IDA in bioimaging were addressed. As a proof of concept, the study achieved mitochondria-targeted imaging of adenosine triphosphate in live cells with signal amplification. This study opens a non-covalent avenue for bioimaging with advancements in tunability, generality, and simplicity, apart from the covalent approach.

Cyclodextrins in drug delivery: applications in gene and combination therapy

Gene therapy is a powerful tool against genetic disorders and cancer, targeting the source of the disease rather than just treating the symptoms. While much of the initial success of gene delivery relied on viral vectors, non-viral vectors are emerging as promising gene delivery systems for efficacious treatment with decreased toxicity concerns. However, the delivery of genetic material is still challenging, and there is a need for vectors with enhanced targeting, reduced toxicity, and controlled release. In this article, we highlight current work in gene therapy which utilizes the cyclic oligosaccharide molecule cyclodextrin (CD). With a number of unique abilities, such as hosting small molecule drugs, acting as a linker or modular component, reducing immunogenicity, and disrupting membranes, CD is a valuable constituent in many delivery systems. These carriers also demonstrate great promise in combination therapies, due to the ease of assembling macromolecular structures and wide variety of chemical derivatives, which allow for customizable delivery systems and co-delivery of therapeutics. The use of combination and personalized therapies can result in improved patient health-modular systems, such as those which incorporate CD, are more conducive to these therapy types. Graphical abstract.

Trifaceted Mickey Mouse Amphiphiles for Programmable Self-Assembly, DNA Complexation and Organ-Selective Gene Delivery

Instilling segregated cationic and lipophilic domains with an angular disposition in a trehalose-based trifaceted macrocyclic scaffold allows engineering patchy molecular nanoparticles leveraging directional interactions that emulate those controlling self-assembling processes in viral capsids. The resulting trilobular amphiphilic derivatives, featuring a Mickey Mouse architecture, can electrostatically interact with plasmid DNA (pDNA) and further engage in hydrophobic contacts to promote condensation into transfectious nanocomplexes. Notably, the topology and internal structure of the cyclooligosaccharide/pDNA co-assemblies can be molded by fine-tuning the valency and characteristics of the cationic and lipophilic patches, which strongly impacts the transfection efficacy in vitro and in vivo. Outstanding organ selectivities can then be programmed with no need of incorporating a biorecognizable motif in the formulation. The results provide a versatile strategy for the construction of fully synthetic and perfectly monodisperse nonviral gene delivery systems uniquely suited for optimization schemes by making cyclooligosaccharide patchiness the focus.

Strategies in the delivery of Cas9 ribonucleoprotein for CRISPR/Cas9 genome editing

CRISPR/Cas9 genome editing has gained rapidly increasing attentions in recent years, however, the translation of this biotechnology into therapy has been hindered by efficient delivery of CRISPR/Cas9 materials into target cells. Direct delivery of CRISPR/Cas9 system as a ribonucleoprotein (RNP) complex consisting of Cas9 protein and single guide RNA (sgRNA) has emerged as a powerful and widespread method for genome editing due to its advantages of transient genome editing and reduced off-target effects. In this review, we summarized the current Cas9 RNP delivery systems including physical approaches and synthetic carriers. The mechanisms and beneficial roles of these strategies in intracellular Cas9 RNP delivery were reviewed. Examples in the development of stimuli-responsive and targeted carriers for RNP delivery are highlighted. Finally, the challenges of current Cas9 RNP delivery systems and perspectives in rational design of next generation materials for this promising field will be discussed.

Cyclodextrin-Based Functional Glyconanomaterials

Cyclodextrins (CDs) have long occupied a prominent position in most pharmaceutical laboratories as "off-the-shelve" tools to manipulate the pharmacokinetics of a broad range of active principles, due to their unique combination of biocompatibility and inclusion abilities. The development of precision chemical methods for their selective functionalization, in combination with "click" multiconjugation procedures, have further leveraged the nanoscaffold nature of these oligosaccharides, creating a direct link between the glyco and the nano worlds. CDs have greatly contributed to understand and exploit the interactions between multivalent glycodisplays and carbohydrate-binding proteins (lectins) and to improve the drug-loading and functional properties of nanomaterials through host-guest strategies. The whole range of capabilities can be enabled through self-assembly, template-assisted assembly or covalent connection of CD/glycan building blocks. This review discusses the advancements made in this field during the last decade and the amazing variety of functional glyconanomaterials empowered by the versatility of the CD component.

Tuning the Topological Landscape of DNA-Cyclodextrin Nanocomplexes by Molecular Design

Original molecular vectors that ensure broad flexibility to tune the shape and surface properties of plasmid DNA (pDNA) condensates are reported herein. The prototypic design involves a cyclodextrin (CD) platform bearing a polycationic cluster at the primary face and a doubly linked aromatic module bridging two consecutive monosaccharide units at the secondary face that behaves as a topology-encoding element. Subtle differences at the molecular level then translate into disparate morphologies at the nanoscale, including rods, worms, toroids, globules, ellipsoids, and spheroids. In vitro evaluation of the transfection capabilities revealed marked selectivity differences as a function of nanocomplex morphology. Remarkably high transfection efficiencies were associated with ellipsoidal or spherical shapes with a lamellar internal arrangement of pDNA chains and CD bilayers. Computational studies support that the stability of such supramolecular edifices is directly related to the tendency of the molecular vector to form noncovalent dimers upon DNA templating. Because the stability of the dimers depends on the protonation state of the polycationic clusters, the coaggregates display pH responsiveness, which facilitates endosomal escape and timely DNA release, a key step in successful transfection. The results provide a versatile strategy for the construction of fully synthetic and perfectly monodisperse nonviral gene delivery systems uniquely suited for optimization schemes.

Click Synthesis of Size- and Shape-Tunable Star Polymers with Functional Macrocyclic Cores for Synergistic DNA Complexation and Delivery

The architectural perfection and multivalency of dendrimers have made them useful for biodelivery via peripheral functionalization and the adjustment of dendrimer generations. Modulation of the core-forming and internal matrix-forming structures offers virtually unlimited opportunities for further optimization, but only in a few cases this has been made compatible with strict diastereomeric purity over molecularly diverse series, low toxicity, and limited synthetic effort. Fully regular star polymers built on biocompatible macrocyclic platforms, such as hyperbranched cyclodextrins, offer advantages in terms of facile synthesis and flexible compositions, but core elaboration in terms of shape and function becomes problematic. Here we report the synthesis and characterization of star polymers consisting of functional trehalose-based macrocyclic cores (cyclotrehalans, CTs) and aminothiourea dendron arms, which can be efficiently synthesized from sequential click reactions of orthogonal monomers, display no cytotoxicity, and efficiently complex and deliver plasmid DNA in vitro and in vivo. When compared with some commercial cationic dendrimers or polymers, the new CT-scaffolded star polymers show better transfection efficiencies in several cell lines and structure-dependent cell selectivity patterns. Notably, the CT core could be predefined to exert Zn(II) complexing or molecular inclusion capabilities, which has been exploited to synergistically boost cell transfection by orders of magnitude and modulate the organ tropism in vivo.

A General Hypoxia-Responsive Molecular Container for Tumor-Targeted Therapy

Enhanced drug delivery can improve the therapeutic efficacy of drugs and help overcome side effects. However, many reported drug-delivery systems are too complex and irreproducible for practical use. In this work, the design of a hypoxia-responsive molecular container based on calixarene, called CAC4A, which presents a significant advance in practical, hypoxia-targeted drug-delivery, is reported. CAC4A enables a wide variety of clinical drugs to be quantitatively loaded to improve their solubility and stability, as well as enable the administration of reduced doses. Furthermore, as a result of its azo functional groups, which are sensitive to reduction within a hypoxic environment, it is possible to achieve tumor-targeted drug-release with reduced side effects. CAC4A fulfils all essential requirements for a drug-delivery system in addition to multiple advantages, including facile preparation, well-defined molecular weight, and structure, and universal applicability. Such features collectively enable supramolecular prodrugs to be formulated simply and reproducibly, with potential for bench-to-bedside translation. Moreover, CAC4A is amenable to other therapy modalities and can be facilely decorated with functional groups and hybridized with nanomaterials, providing ample possibilities for its role in future drug-delivery systems.

Macrocyclic polyamine [12]aneN3 modified triphenylamine-pyrazine derivatives as efficient non-viral gene vectors with AIE and two-photon imaging properties

[12]aneN₃ modified triphenylamine-pyrazines as non-viral gene vectors with AIE and two-photon imaging properties.

Supramolecular Nanotheranostics

This supramolecular nanotheranostics special issue collected a total of 17 review articles and 3 research articles broadly covering the current and emerging supramolecular nanotheranostics.

Functional self-assembled nanovesicles based on β-cyclodextrin, liposomes and adamantyl guanidines as potential nonviral gene delivery vectors

Multicomponent self-assembled supramolecular nanovesicles based on an amphiphilic derivative of β-cyclodextrin and phosphatidylcholine liposomes (PC-liposomes) functionalized with four structurally different adamantyl guanidines were prepared and characterized. Incorporation efficiency of the examined adamantyl guanidines as well as size and surface charge of the prepared supramolecular nanovesicles was determined. Changes in the surface charge of the prepared nanovesicles confirmed that guanidinium groups were exposed on the surface. ITC and 1H NMR spectroscopy complemented by molecular dynamics (MD) simulations were used to elucidate the structural data and stability of the inclusion complexes of β-cyclodextrin and adamantyl guanidines (AG1-5). The results are consistent and point to a significant contribution of the guanylhydrazone residue to the complexation process for AG1 and AG2 with β-cyclodextrin. In order to evaluate the potential of the self-assembled supramolecular nanomaterial as a nonviral gene delivery vector, fluorescence correlation spectroscopy was used. It showed that the prepared nanovesicles functionalized with adamantyl guanidines AG1-4 effectively recognize and bind the fluorescently labelled DNA. Furthermore, gel electrophoretic assay confirmed the formation of nanoplexes of functionalized nanovesicles and plasmid DNA. These findings together suggest that the designed supramolecular nanovesicles could be successfully applied as nonviral gene delivery vectors.