Preorganized, Macromolecular, Gene-Delivery Systems

Cellular Uptake of Cell-Penetrating Peptides Activated by Amphiphilic p-Sulfonatocalix[4]arenes

We report the synthesis of a series of amphiphilic p-sulfonatocalix[4]arenes with varying alkyl chain lengths (CX4-Cn) and their application as efficient counterion activators for membrane transport of cell-penetrating peptides (CPPs). The enhanced membrane activity is confirmed with the carboxyfluorescein (CF) assay in vesicles and by the direct cytosolic delivery of CPPs into CHO-K1, HCT 116, and KTC-1 cells enabling excellent cellular uptake of the CPPs into two cancer cell lines. Intracellular delivery was confirmed by fluorescence microscopy after CPP entry into live cells mediated by CX4-Cn, which was also quantified after cell lysis by fluorescence spectroscopy. The results present the first systematic exploration of structure-activity relationships for calixarene-based counterion activators and show that CX4-Cn are exceptionally effective in cellular delivery of CPPs. The dodecyl derivative, CX4-C12, serves as best activator. A first mechanistic insight is provided by efficient CPP uptake at 4 °C and in the presence of the endocytosis inhibitor dynasore, which indicates a direct translocation of the CPP-counterion complexes into the cytosol and highlights the potential benefits of CX4-Cn for efficient and direct translocation of CPPs and CPP-conjugated cargo molecules into the cytosol of live cells.

Advancements in application of chitosan and cyclodextrins in biomedicine and pharmaceutics: recent progress and future trends

The global community is faced with numerous health concerns such as cancer, cardiovascular and neurological diseases, diabetes, joint pain, osteoporosis, among others. With the advancement of research in the fields of materials chemistry and medicine, pharmaceutical technology and biomedical analysis have entered a new stage of development. The utilization of natural oligosaccharides and polysaccharides in pharmaceutical/biomedical studies has gained significant attention. Over the past decade, several studies have shown that chitosan and cyclodextrin have promising biomedical implications in background analysis, ongoing development, and critical applications in biomedical and pharmaceutical research fields. This review introduces different types of saccharides/natural biopolymers such as chitosan and cyclodextrin and discusses their wide-ranging applications in the biomedical/pharmaceutical research area. Recent research advances in pharmaceutics and drug delivery based on cyclodextrin, and their response to smart stimuli, as well as the biological functions of cyclodextrin and chitosan, such as the immunomodulatory effects, antioxidant, and antibacterial properties, have also been discussed, along with their applications in tissue engineering, wound dressing, and drug delivery systems. Finally, the innovative applications of chitosan and cyclodextrin in the pharmaceutical/biomedicine were reviewed, and current challenges, research/technological gaps, and future development opportunities were surveyed.

Trehalose-polyamine/DNA nanocomplexes: impact of vector architecture on cell and organ transfection selectivity

A novel family of precision-engineered gene vectors with well-defined structures built on trehalose and trehalose-based macrocycles (cyclotrehalans) comprising linear or cyclic polyamine heads have been synthesized through procedures that exploit click chemistry reactions. The strategy was conceived to enable systematic structural variations and, at the same time, ensuring that enantiomerically pure vectors are obtained. Notably, changes in the molecular architecture translated into topological differences at the nanoscale upon co-assembly with plasmid DNA, especially regarding the presence of regions with short- or long-range internal order as observed by TEM. In vitro and in vivo experiments further evidenced a significant impact on cell and organ transfection selectivity. Altogether, the results highlight the potential of trehalose-polyamine/pDNA nanocomplex monoformulations to achieve targeting transfection without the need for any additional cell- or organ-sorting component.

Prospects of charged cyclodextrins in biomedical applications

Cyclodextrins (CDs), recognized for their unique ability to form inclusion complexes, have seen broad utilization across various scientific fields. Recently, there has been a surge of interest in the use of charged cyclodextrins for biomedical applications, owing to their enhanced properties, such as superior solubility and improved molecular recognition compared to neutral CDs. Despite the growing literature, a comprehensive review of the biomedical utilisations of multi-charged cyclodextrins is scarce. This review provides a comprehensive exploration of the emerging prospects of charged cyclodextrin-based assemblies in the field of biomedical applications. Focusing on drug delivery systems, the review details how charged CDs enhance drug solubility and stability, reduce toxicity, and enable targeted and controlled drug release. Furthermore, the review highlights the role of charged CDs in gene therapy, notably their potential for DNA/RNA binding, cellular uptake, degradation protection, and targeted gene delivery. The promising potential of charged CDs in antibacterial and antiviral therapies, including photodynamic therapies, biofilm control, and viral replication inhibition, is discussed. Concluding with a future outlook, this review highlights the potential challenges and advancements that could propel charged CDs to the forefront of biomedicine.

Sialic Acid-Targeted Cyclodextrin-Based Nanoparticles Deliver CSF-1R siRNA and Reprogram Tumour-Associated Macrophages for Immunotherapy of Prostate Cancer

Prostate cancer remains a serious condition threatening the health of men. Due to the complicated nature of the tumour microenvironment (TME), conventional treatments face challenges including poor prognosis and tumour resistance, therefore new therapeutic strategies are urgently needed. Small interfering RNA (siRNA), a double-stranded non-coding RNA, regulates specific gene expression through RNA interference. Tumour-associated macrophages (TAMs) are a potential therapeutic target in cancer immunotherapy. Colony stimulating factor-1/colony stimulating factor-1 receptor (CSF-1/CSF-1R) signaling pathway plays a crucial role in the polarization of the immunosuppressive TAMs, M2 macrophages. Downregulation of CSF-1R is known to reprogram the immunosuppressive TAMs, M2 macrophages, to the immunostimulatory phenotype, M1 macrophages. Sialic acid is a ligand for Siglec-1 (CD169) which is overexpressed on M2 macrophages with little expression in other phenotypes. Therefore, a sialic acid-targeted cyclodextrin-based nanoparticle was developed to specifically deliver CSF-1R siRNA to M2 macrophages. The nanoparticles were studied in vitro using both human and mouse prostate cancer cell lines. Results show that the targeted nanoparticles achieved cell specific delivery to M2 macrophages via the sialic acid-CD169 axis. The expression of CSF-1R was significantly downregulated in M2 macrophages (29.64% for targeted vs 19.31% for non-targeted nanoparticles in THP-1-derived M2 macrophages and 38.94% for targeted vs 18.51% for non-targeted nanoparticles in RAW 264.7-derived M2 macrophages, n = 4, p < 0.01). The resulting reprograming of M2 macrophages to M1 enhanced the level of apoptosis in the prostate cancer cells in a Transwell model (49.17% for targeted vs 37.68% for non-targeted nanoparticles in PC-3 cells and 69.15% for targeted vs 44.73% for non-targeted nanoparticles in TRAMP C1 cells, n = 3, p < 0.01). Thus, this targeted cyclodextrin-based siRNA drug delivery system provides a potential strategy for prostate cancer immunotherapy.

Carbon-based nanostructures for cancer therapy and drug delivery applications

Synthesis, design, characterization, and application of carbon-based nanostructures (CBNSs) as drug carriers have attracted a great deal of interest over the past half of the century because of their promising chemical, thermal, physical, optical, mechanical, and electrical properties and their structural diversity. CBNSs are well-known in drug delivery applications due to their unique features such as easy cellular uptake, high drug loading ability, and thermal ablation. CBNSs, including carbon nanotubes, fullerenes, nanodiamond, graphene, and carbon quantum dots have been quite broadly examined for drug delivery systems. This review not only summarizes the most recent studies on developing carbon-based nanostructures for drug delivery (e.g. delivery carrier, cancer therapy and bioimaging), but also tries to deal with the challenges and opportunities resulting from the expansion in use of these materials in the realm of drug delivery. This class of nanomaterials requires advanced techniques for synthesis and surface modifications, yet a lot of critical questions such as their toxicity, biodistribution, pharmacokinetics, and fate of CBNSs in biological systems must be answered.

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.

Multivalent cationic dendrofullerenes for gene transfer: synthesis and DNA complexation

Non-viral nucleic acid vectors able to display high transfection efficiencies with low toxicity and overcoming the multiple biological barriers are needed to further develop the clinical applications of gene therapy. The synthesis of hexakis-adducts of [60]fullerene endowed with 12, 24 and 36 positive ammonium groups and a tridecafullerene appended with 120 positive charges has been performed. The delivery of a plasmid containing the green fluorescent protein (EGFP) gene into HEK293 (Human Embryonic Kidney) cells resulting in effective gene expression has demonstrated the efficacy of these compounds to form polyplexes with DNA. Particularly, giant tridecafullerene macromolecules have shown higher efficiency in the complexation and transfection of DNA. Thus, they can be considered as promising non-viral vectors for transfection purposes.

Cationic lipids for gene delivery: many players, one goal

Lipid-based carriers represent the most widely used alternative to viral vectors for gene expression and gene silencing purposes. This class of non-viral vectors is particularly attractive for their ease of synthesis and chemical modifications to endow them with desirable properties. Despite combinatorial approaches have led to the generation of a large number of cationic lipids displaying different supramolecular structures and improved behavior, additional effort is needed towards the development of more and more effective cationic lipids for transfection purposes. With this review, we seek to highlight the great progress made in the design of each and every constituent domain of cationic lipids, that is, the chemical structure of the headgroup, linker and hydrophobic moieties, and on the specific effect on the assembly with nucleic acids. Since the complexity of such systems is known to affect their performances, the role of formulation, stability and phase behavior on the transfection efficiency of such assemblies will be thoroughly discussed. Our objective is to provide a conceptual framework for the development of ever more performing lipid gene delivery vectors.

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.

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.

Biomedical applications of carbon nanomaterials: Drug and gene delivery potentials

One of the major components in the development of nanomedicines is the choice of the right biomaterial, which notably determines the subsequent biological responses. The popularity of carbon nanomaterials (CNMs) has been on the rise due to their numerous applications in the fields of drug delivery, bioimaging, tissue engineering, and biosensing. Owing to their considerably high surface area, multifunctional surface chemistry, and excellent optical activity, novel functionalized CNMs possess efficient drug-loading capacity, biocompatibility, and lack of immunogenicity. Over the past few decades, several advances have been made on the functionalization of CNMs to minimize their health concerns and enhance their biosafety. Recent evidence has also implied that CNMs can be functionalized with bioactive peptides, proteins, nucleic acids, and drugs to achieve composites with remarkably low toxicity and high pharmaceutical efficiency. This review focuses on the three main classes of CNMs, including fullerenes, graphenes, and carbon nanotubes, and their recent biomedical applications.

Plasmid-Templated Control of DNA-Cyclodextrin Nanoparticle Morphology through Molecular Vector Design for Effective Gene Delivery

Engineering self-assembled superstructures through complexation of plasmid DNA (pDNA) and single-isomer nanometric size macromolecules (molecular nanoparticles) is a promising strategy for gene delivery. Notably, the functionality and overall architecture of the vector can be precisely molded at the atomic level by chemical tailoring, thereby enabling unprecedented opportunities for structure/self-assembling/pDNA delivery relationship studies. Beyond this notion, by judiciously preorganizing the functional elements in cyclodextrin (CD)-based molecular nanoparticles through covalent dimerization, here we demonstrate that the morphology of the resulting nanocomplexes (CDplexes) can be tuned, from spherical to ellipsoidal, rod-type, or worm-like nanoparticles, which makes it possible to gain understanding of their shape-dependent transfection properties. The experimental findings are in agreement with a shift from chelate to cross-linking interactions on going from primary-face- to secondary-face-linked CD dimers, the pDNA partner acting as an active payload and as a template. Most interestingly, the transfection efficiency in different cells was shown to be differently impacted by modifications of the CDplex morphology, which has led to the identification of an optimal prototype for tissue-selective DNA delivery to the spleen in vivo.

Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays

Three polyaminocyclodextrin materials, obtained by direct reaction between heptakis(6-deoxy-6-iodo)-β-cyclodextrin and the proper linear polyamines, were investigated for their binding properties, in order to assess their potential applications in biological systems, such as vectors for simultaneous drug and gene cellular uptake or alternatively for the protection of macromolecules. In particular, we exploited polarimetry to test their interaction with some model p-nitroaniline derivatives, chosen as probe guests. The data obtained indicate that binding inside the host cavity is mainly affected by interplay between Coulomb interactions and conformational restraints. Moreover, simultaneous interaction of the cationic polyamine pendant bush at the primary rim was positively assessed. Insights on quantitative aspects of the interaction between our materials and polyanions were investigated by studying the binding with sodium alginate. Finally, the complexation abilities of the same materials towards polynucleotides were assessed by studying their interaction with the model plasmid pUC19. Our results positively highlight the ability of our materials to exploit both the cavity and the polycationic branches, thus functioning as bimodal ligands.

Molecular determinants for cyclo-oligosaccharide-based nanoparticle-mediated effective siRNA transfection

AIM

To study the structural requirements that a cyclooligosaccharide-based nanoparticle must fulfill to be an efficient siRNA transfection vector.

MATERIALS & METHODS

siRNA protection from degradation by RNAses, transfection efficiency and the thermodynamic parameters of the nanoparticle/siRNA interactions were studied on pairs of amphiphilic molecules using biochemical techniques and molecular dynamics.

RESULTS

The lower the siRNA solvent accessible surface area in the presence of the nanoparticle, higher the protection from RNAse-mediated degradation in the corresponding nanocomplex; a moderate nanoparticle/siRNA binding energy value further facilitates reversible complexation and binding to the target cellular mRNA.

CONCLUSION

The use, in advance, of these parameters will provide a useful indication of the potential of a molecular nanoparticle as siRNA transfecting vector.

Biophysics and protein corona analysis of Janus cyclodextrin-DNA nanocomplexes. Efficient cellular transfection on cancer cells

The self-assembling processes underlining the capabilities of facially differentiated ("Janus") polycationic amphiphilic cyclodextrins (paCDs) as non-viral gene nanocarriers have been investigated by a pluridisciplinary approach. Three representative Janus paCDs bearing a common tetradecahexanoyl multitail domain at the secondary face and differing in the topology of the cluster of amino groups at the primary side were selected for this study. All of them compact pEGFP-C3 plasmid DNA and promote transfection in HeLa and MCF-7 cells, both in absence and in presence of human serum. The electrochemical and structural characteristics of the paCD-pDNA complexes (CDplexes) have been studied by using zeta potential, DLS, SAXS, and cryo-TEM. paCDs and pDNA, when assembled in CDplexes, render effective charges that are lower than the nominal ones. The CDplexes show a self-assembling pattern corresponding to multilamellar lyotropic liquid crystal phases, characterized by a lamellar stacking of bilayers of the CD-based vectors with anionic pDNA sandwiched among them. When exposed to human serum, either in the absence or in the presence of pDNA, the surface of the cationic CD-based vector becomes coated by a protein corona (PC) whose composition has been analyzed by nanoLC-MS/MS. Some of the CDplexes herein studied showed moderate-to-high transfection levels in HeLa and MCF-7 cancer cells combined with moderate-to-high cell viabilities, as determined by FACS and MTT reduction assays. The ensemble of data provides a detail picture of the paCD-pDNA-PC association processes and a rational base to exploit the protein corona for targeted gene delivery on future in vivo applications.

A Bimodal, Cationic, and Water-Soluble Calix[4]arene Conjugate: Design, Synthesis, Characterization, and Transfection of Red Fluorescent Protein Encoded Plasmid in Cancer Cells

A new bimodal fluorescent cationic calix[4]arene (L1) conjugate has been synthesized in multiple steps and well characterized by NMR and electrospray ionization-mass spectrometry (ESI-MS) techniques. L1 has been investigated for its DNA binding ability by various spectroscopy techniques like absorption, fluorescence, and circular dichroism (CD). The formation of L1-DNA complex has been confirmed by the gel electrophoresis in the presence of incremental concentration of L1. To visualize the packing of the plasmid (pBR322), detailed tapping mode atomic force microscopy study has been performed, which revealed blob-like structure of plasmid upon addition of the incremental amount of L1. Concentration dependent transfection ability of L1 has been established in MCF-7 cells by confocal microscopy by carrying the red fluorescent protein (RFP) encoded plasmid pCMV-tdTomato-N1 to emit both intrinsic fluorescence of L1 as well as that from RFP. All this has been possible in the absence of any adjuvant phospholipids (DOPE) that are commonly used as helper. Further transfection efficiency of L1 has been compared with the commercially available lipofectamine (LTX) in two cancer cell lines, MCF 7 and SH-SY5Y, and found that the L1 is as efficient as that of LTX. Hence, L1 is an efficient and effective cargo to transport genetic material into the cells.

Radical-Mediated C-H Functionalization: A Strategy for Access to Modified Cyclodextrins

A simple and efficient radical C-H functionalization to access modified cyclodextrins (CDs) has been developed. The well-defined conformation of glycosidic and aglyconic bonds in α-, β-, and γ-CDs favors the intramolecular 1,8-hydrogen atom transfer (HAT) promoted by the 6^I-O-yl radical, which abstracts regioselectively the hydrogen at C5^II of the contiguous pyranose. The C5^II-radical evolves by a polar crossover mechanism to a stable 1,3,5-trioxocane ring between two adjacent glucoses or alternatively triggers the inversion of one α-d-glucose into a 5-C-acetoxy-β-l-idose unit possessing a ¹C₄ conformation. The 6^I,IV- and 6^I,III-diols of α- and β-CDs behave similarly to the monoalcohols, forming mostly compounds originating from two 1,8-HAT consecutive processes. In the case of 6^I,II-diols the proximity of the two 6-O-yl radicals in adjacent sugar units allows the formation of unique lactone rings within the CD framework via a 1,8-HAT-β-scission tandem mechanism. X-ray diffraction carried out on the crystalline 1,4-bis(trioxocane)-α-CD derivative shows a severe distortion toward a narrower elliptical shape for the primary face.

Influence of Growth Characteristics of Induced Pluripotent Stem Cells on Their Uptake Efficiency for Layer-by-Layer Microcarriers

Induced pluripotent stem cells (iPSCs) have the ability to differentiate into any specialized somatic cell type, which makes them an attractive tool for a wide variety of scientific approaches, including regenerative medicine. However, their pluripotent state and their growth in compact colonies render them difficult to access and, therefore, restrict delivery of specific agents for cell manipulation. Thus, our investigation focus was set on the evaluation of the capability of layer-by-layer (LbL) designed microcarriers to serve as a potential drug delivery system to iPSCs, as they offer several appealing advantages. Most notably, these carriers allow for the transport of active agents in a protected environment and for a rather specific delivery through surface modifications. As we could show, charge and mode of LbL carrier application as well as the size of the iPSC colonies determine the interaction with and the uptake rate by iPSCs. None of the examined conditions had an influence on iPSC colony properties such as colony morphology and size or maintenance of pluripotent properties. An overall interaction rate of LbL carriers with iPSCs of up to 20% was achieved. Those data emphasize the applicability of LbL carriers for stem cell research. Additionally, the potential use of LbL carriers as a promising delivery tool for iPSCs was contrasted to viral particles and liposomes. The identified differences among those delivery tools have substantiated our major conclusion that LbL carrier uptake rate is influenced by characteristic features of the iPSC colonies (most notably colony size) in addition to their surface charges.

Recent progress in gene therapy to deliver nucleic acids with multivalent cationic vectors

Due to the potential use as transfecting agents of nucleic acids (DNA or RNA), multivalent cationic non-viral vectors have received special attention in the last decade. Much effort has been addressed to synthesize more efficient and biocompatible gene vectors able to transport nucleic acids into the cells without provoking an immune response. Among them, the mostly explored to compact and transfect nucleic acids are: (a) gemini and multivalent cationic lipids, mixed with a helper lipid, by forming lipoplexes; and (b) cationic polymers, polycations, and polyrotaxanes, by forming polyplexes. This review is focused on the progress and recent advances experimented in this area, mainly during the present decade, devoting special attention to the lipoplexes and polyplexes, as follows: (a) to its biophysical characterization (mainly electrostatics, structure, size and morphology) using a wide variety of experimental methods; and (b) to its biological activity (transfection efficacy and cytotoxicity) addressed to confirm the optimum formulations and viability of these complexes as very promising gene vectors of nucleic acids in nanomedicine.

Soft Supramolecular Nanoparticles by Noncovalent and Host-Guest Interactions

Supramolecular chemistry provides a tool for the formation of highly ordered structures by means of noncovalent interactions. Soft supramolecular nanoparticles are self-assembled nanoassemblies based on small building blocks and stabilized by basic noncovalent interactions, selective host-guest interactions, or a combination of different interaction types. This review provides an overview of the existing approaches for the formation of supramolecular nanoparticles by various types of noncovalent interactions, with a strong focus on host-guest-mediated assemblies. The approaches are ordered based on the nature of the stabilizing supramolecular interaction, while focusing on the aspects that determine the particle structure. Where applicable, the use of these self-assembled nanostructures as vectors in molecular diagnostics and therapeutics is described as well. The stable yet reversible nature of supramolecular interactions and their chemical flexibility offer great prospects for the development of highly engineered nanoparticles which are compatible with the complexity of living systems.

Deciphering of polycationic carbohydrate based non-viral gene delivery agents by ESI-LTQ-Orbitrap using CID/HCD pairwise tandem mass spectrometry

In the study herein, we demonstrated that ESI-(MS)MS combining CID and HCD is a useful tool for the structural deciphering of five representative members of a polycationic cyclodextrin library used as non viral agents for gene delivery.

Cyclodextrin-based facial amphiphiles: assessing the impact of the hydrophilic–lipophilic balance in the self-assembly, DNA complexation and gene delivery capabilities

Precise tailoring of cationic and lipophilic domains of cyclodextrin-based amphiphiles permits the control of their self-assembling and gene delivery capabilities.

Photosynthesized silver–polyaminocyclodextrin nanocomposites as promising antibacterial agents with improved activity

Ag nanocomposites were prepared by photoreduction of ammoniacal silver acetate in the presence of poly-{6-[3-(2-(3-aminopropylamino)ethylamino)propylamino]}-(6-deoxy)-β-CD (amCD).

Trehalose-based Janus cyclooligosaccharides: the “Click” synthesis and DNA-directed assembly into pH-sensitive transfectious nanoparticles

Trehalose-based Janus cyclooligosaccharides undergo DNA-promoted self-assembling.

Cyclodextrin- and calixarene-based polycationic amphiphiles as gene delivery systems: a structure-activity relationship study

Multi-head/multi-tail facial amphiphiles built on cyclodextrin (CD) and calixarene (CA) scaffolds are paradigmatic examples of monodisperse gene delivery systems. The possibility to precisely control the architectural features at the molecular level offers unprecedented opportunities for conducting structure-activity relationship studies. A major requirement for those channels is the design of a sufficiently diverse ensemble of compounds for parallel evaluation of their capabilities to condense DNA into transfection nanoparticles where the gene material is protected from the environment. Here we have undertaken the preparation of an oriented library of β-cyclodextrin (βCD) and calix[4]arene (CA4) vectors with facial amphiphilic character designed to ascertain the effect of the cationic head nature (aminothiourea-, arginine- or guanidine-type groups) and the macrocyclic platform on the abilities to complex plasmid DNA (pDNA) and in the efficiency of the resulting nanocomplexes to transfect cells in vitro. The hydrophobic domain, formed by hexanoyl or hexyl chains, remains constant in each series, matching the overall structure found to be optimal in previous studies. DLS, TEM and AFM data support that all the compounds self-assemble in the presence of pDNA through a process that involves initially electrostatic interactions followed by formation of βCD or CA4 bilayers between the oligonucleotide filaments. Spherical transfectious nanoparticles that are monomolecular in DNA are thus obtained. Evaluation in epithelial COS-7 and human rhabdomyosarcoma RD-4 cells evidenced the importance of having primary amino groups in the vector to warrant high levels of transfection, probably because of their buffering capacity. The results indicate that the optimal cationic head depends on the macrocyclic core, aminothiourea groups being preferred in the βCD series and arginine groups in the CA4 series. Whereas the transfection efficiency relationships remain essentially unchanged within each series, irrespective of the cell type, the optimal platform (βD or CA4) strongly depends on the cell type. The results illustrate the potential of monodisperse vector prototypes and diversity-oriented strategies on identifying the optimal candidates for gene therapy applications.

Moulding calixarenes for biomacromolecule targeting

After their successful use as a preorganized platform for the preparation of receptors for metal ions and small neutral molecules over the last 15 years, calixarenes are enjoying a renaissance of popularity as scaffolds for ligands that are able to efficiently and selectively target macromolecules such as proteins/enzymes, nucleic acids and lipids. This feature article summarizes the peculiar factors characterizing the calixarene structure and properties, as well as outlines the main rules that can be used to turn such macrocycles into efficient and successful ligands for these classes of biomacromolecules. Factors that affect the multivalent properties of calixarenes, such as the size, conformation and stereochemical presentation of binding groups or their amphiphilicity and hybrid character, are described in detail with the use of a few selected examples from the literature. Perspectives and applications of these ligands in bionanotechnology and nanomedicine, such as protein sensing and inhibition, gene-delivery, targeted drug-delivery and cell imaging, are also discussed.

Dynamic constitutional frameworks (DCFs) as nanovectors for cellular delivery of DNA

We introduce Dynamic Constitutional Frameworks (DCFs), macromolecular structures that efficiently bind and transfect double stranded DNA. DCFs are easily synthesizable adaptive 3D networks consisting of core connection centres reversibly linked via labile imine bonds both to linear polyethyleneglycol (PEG, ∼1500 Da) and to branched polyethyleneimine (bPEI, ∼800 Da). DCFs bind linear and plasmid DNA, forming particulate polyplexes of 40-200 nm in diameter. The polyplexes are stable during gel electrophoresis, well tolerated by cells in culture, and exhibit significant transfection activity. We show that an optimal balance of PEG and bPEI components is important for building DCFs that are non-toxic and exhibit good cellular transfection activity. Our study demonstrates the versatility and effectiveness of DCFs as promising new vectors for DNA delivery.

Polycationic Macrocyclic Scaffolds as Potential Non-Viral Vectors of DNA: A Multidisciplinary Study

The potential of lipoplexes constituted by the DNA pEGFP-C3 (encoding green fluorescent protein), polycationic calixarene-based macrocyclic vector (CxCL) with a lipidic matrix (herein named TMAC4), and zwitterionic lipid 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) as nontoxic DNA vectors has been analyzed from both biophysical and biochemical perspectives. For that purpose, several experimental methods, such as zeta potential (PALS methodology), agarose gel electrophoresis, small-angle X-ray scattering (SAXS), transmission electronic cryo-microscopy (cryo-TEM), atomic force microscopy (AFM), fluorescence microscopy, and cytotoxicity assays have been used. The electrochemical study shows that TMAC4 has 100% of its nominal charge available, whereas pDNA presents an effective negative charge that is only 10% that of its nominal one. PALS studies indicate the presence of three populations of nanoaggregates in TMAC4/DOPE lipid mixtures, with sizes of approximately 100, 17, and 6 nm, compatible with liposomes, oblate micelles, and spherical micelles, respectively, the first two also being detected by cryo-TEM. However, in the presence of pDNA, this mixture is organized in Lα multilamellar structures at all compositions. In fact, cryo-TEM micrographs show two types of multilamellar aggregation patterns: cluster-type at low and moderate CxCL molar fractions in the TMAC4/DOPE lipid mixture (α = 0.2 and 0.5), and fingerprint-type (FP), which are only present at low CxCL molar fraction (α = 0.2). This structural scenario has also been observed in SAXS diffractograms, including the coexistence of two different phases when DOPE dominates in the mixture. AFM experiments at α = 0.2 provide evidence that pDNA makes the lipid bilayer more deformable, thus promoting a potential enhancement in the capability of penetrating the cells. In fact, the best transfection perfomances of these TMAC4/DOPE-pDNA lipoplexes have been obtained at low CxCL molar fractions (α = 0.2) and a moderate-to-high effective charge ratio (ρeff = 20). Presumably, the coexistence of two lamellar phases is responsible for the better TE performance at low α.

Synthesis of bifunctional molecules containing [12]aneN3 and coumarin moieties as effective DNA condensation agents and new non-viral gene vectors

Bifunctional molecules with different combinations of [12]aneN₃ and coumarin moieties were successfully applied in DNA condensation and gene transfection.

Cationic amphiphilic calixarenes to compact DNA into small nanoparticles for gene delivery

Cationic amphiphilic calixarenes with longer alkyl chains are less cytotoxic and their virus-sized DNA nanoparticles exhibit higher transfection efficiency.

Cell uptake mechanisms of glycosylated cationic pDNA–cyclodextrin nanoparticles

β-Cyclodextrin-based glycoCDplexes are internalized through several redundant pathways whose relative prevalence depends on the coating sugar and on the cell line.

Harmonized tuning of nucleic acid and lectin binding properties with multivalent cyclodextrins for macrophage-selective gene delivery

Polycationic amphiphilic cyclodextrins (paCDs) have been shown to behave as efficient non-viral gene carriers paralleling the efficacy of commercial vectors towards a variety of cell lines.

Fucofullerenes as tight ligands of RSL and LecB, two bacterial lectins

A series of water-soluble glycofullerenes containing up to 24 fucose residues were tested against the two bacterial lectins LecB and RSL, and C60(E)12 bearing 24 fucose residues appeared to be the best known inhibitor of both lectins to date.

Hybrid fullerene conjugates as vectors for DNA cell-delivery

C60-PEI and C60-PEG-PEI as efficient binders of dsDNA, with good transfection up to 25%, high cytocompatibility and cell proliferation up to 200%.

Alkylene-bridged viologen dendrimers: versatile cell delivery tools with biosensing properties

The synthesis of two types of viologen dendrimers with peripheral carboxyl groups is described. Their interaction with plasmid DNA and CT-DNA and the influence of time evolution and electrolyte on dendriplex formation have been electrochemically investigated. A negative potential shift appearing in the cyclic voltammograms of the dendrimers indicates dendriplex formation on the time scale of 15 to 19 minutes, i.e. similar to those determined empirically for other dendrimer types. The presence or absence of the negative potential shift can be used to check the stability towards sodium chloride and different cell growth media directing to sucrose for cell incubation experiments. The electrolyte content of commercially available cell growth media inhibits the dendriplex formation in solution prior to plasmid addition. Furthermore, a low salt stability of 20 mM sodium chloride for viologen dendriplexes has been confirmed, also recommending the use of lysosomotropic sucrose. The two types of viologen dendrimers have been combined with two plasmids differing in the number of base pairs. Four immortal cell lines have been tested to check the suitability of viologen dendriplexes as gene delivery systems. Probably due to the absence of terminal amino groups and endosomolytic substances only a small transfection efficiency of dendriplexes was achieved at low pH, generally excluding in vivo applications. With the larger pHSV-eGFP plasmid (5743 bp) no transfected cells were observed indicating a preference for shorter plasmids.

The impact of copper-catalyzed alkyne-azide 1,3-dipolar cycloaddition in fullerene chemistry

Click reactions largely cross the borders of organic synthetic chemistry and are now at the forefront of many interdisciplinary studies at the interfaces between chemistry, physics, and biology. As part of this research, our group is involved in a program on the development of clickable fullerene building blocks and their application in the preparation of a large variety of new advanced materials and bioactive compounds. Importantly, the introduction of the click chemistry concept in fullerene chemistry allowed us to produce compounds that would barely be accessible by using the classical tools of fullerene chemistry. This is particularly the case for the conjugation of fullerenes with other carbon nanoforms, such as carbon nanohorns and graphene. It is also the case for most of the sophisticated molecular ensembles constructed from clickable fullerene hexa-adduct building blocks. In this paper, we have summarized our ongoing progress in this particular field.