Chitosan nanoparticles fabricated through host-guest interaction for enhancing the immunostimulatory effect of CpG oligodeoxynucleotide.

CpG oligodeoxynucleotides (CpG ODNs) which can induce innate immune responses and promote adaptive immune responses, are powerful tools in defeating diseases. Here, a novel chitosan nanoparticle (CS-NPs) based on host-guest interaction has been designed for encapsulation and delivery of CpG ODNs for the first time. The CS-NPs exhibited high encapsulation efficiency (98.3%) of CpG ODNs and remained stable in storage under room temperature for at least 7 days. CS-NPs can also prevent CpG ODN diffusion at pH 7. The results of confocal laser scanning microscope images and flow cytometry show that CS-NPs can also be efficiently delivered into living cells. Furthermore, CpG@CS-NPs can increase the immunostimulatory activity of CpG ODNs. Raw 264.7 cells treated with CpG@CS-NPs demonstrated upregulation of both TNF-α and IL-6 cytokines by 13% and 40%, respectively. The newly developed CpG@CS-NPs were thus identified as an efficient system to deliver CpG-ODNs to treat various diseases.

Genistein-Derived ROS-Responsive Nanoparticles Relieve Colitis by Regulating Mucosal Homeostasis.

Disruption of intestinal homeostasis is an important event in the development of inflammatory bowel disease (IBD), and genistein (GEN) is a candidate medicine to prevent IBD. However, the clinical application of GEN is restricted owing to its low oral bioavailability. Herein, a reactive oxygen species (ROS)-responsive nanomaterial (defined as GEN-NP2) containing superoxidase dismutase-mimetic temporally conjugated ß-cyclodextrin and 4-(hydroxymethyl)phenylboronic acid pinacol ester-modified GEN was prepared. GEN-NP2 effectively delivered GEN to the inflammation site and protected GEN from rapid metabolism and elimination in the gastrointestinal tract. In response to high ROS levels, GEN was site-specifically released and accumulated at inflammatory sites. Mechanistically, GEN-NP2 effectively increased the expression of estrogen receptor ß (ERß), simultaneously reduced the expression of proinflammatory mediators (apoptosis-associated speck-like protein containing a CARD (ASC) and Caspase1-p20), attenuated the infiltration of inflammatory cells, promoted autophagy of intestinal epithelial cells, inhibited the secretion of interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α), modulated the gut microbiota, and ultimately alleviated colitis. In addition, the oral administration of these nanoparticles showed excellent safety, thereby providing confidence in the further development of precise treatments for IBD.

Supramolecular Polymerization-Induced Nanoassemblies for Self-Augmented Cascade Chemotherapy and Chemodynamic Therapy of Tumor.

The clinical application of chemodynamic therapy is impeded by the insufficient intracellular H2 O2 level in tumor tissues. Herein, we developed a supramolecular nanoparticle via a simple one-step supramolecular polymerization-induced self-assembly process using platinum (IV) complex-modified ß-cyclodextrin-ferrocene conjugates as supramolecular monomers. The supramolecular nanoparticles could dissociate rapidly upon exposure to endogenous H2 O2 in the tumor and release hydroxyl radicals as well as platinum (IV) prodrugs in situ, which is reduced into cisplatin to significantly promote the generation of H2 O2 in the tumor tissue. Thus, the supramolecular nanomedicine overcomes the limitation of conventional chemodynamic therapy via the self-augmented cascade radical generation and drug release. In addition, dissociated supramolecular nanoparticles could be readily excreted from the body via renal clearance to effectively avoid systemic toxicity and ensure long term biocompatibility of the nanomedicine. This work may provide new insights on the design and development of novel supramolecular nanoassemblies for cascade chemo/chemodynamic therapy.

Cyclodextrin functionalized agarose gel with low gelling temperature for controlled drug delivery systems.

Conventional agaroses with high gelling temperature are limited to apply to the field of drug delivery. In this study, ß-cyclodextrin (ßCD) functionalized agarose (CFA) with low gelling temperature was successfully prepared from ethylenediamine-functionalized agarose using mono-succinyl ßCD. The gelling temperature of CFA dramatically decreased to 26.7 °C from 65 °C and the melting temperature declined from 95 °C to 66.1 °C. Upon drug loading, CFA can be used at 30 °C because of its low gelling temperature compared to agarose. CFA gel could be used both for bovine serum albumin as a full release, and for the doxorubicin (DOX) for sustained release, via inclusion complexation of ßCD. Furthermore, cytotoxicity tests revealed that CFA was noncytotoxic. DOX in the CFA gel could retain the anti-cancer activity. Newly synthesized CFA with low gelling temperature offer a new means for the development of hydrogel-based delivery systems for a variety of therapeutic drugs.

Dual delivery of tuberculosis drugs via cyclodextrin conjugated curdlan nanoparticles to infected macrophages.

In tuberculosis, macrophages serve as a host for Mycobacterium tuberculosis and hence targeting them with nanoparticles-based drug delivery could be the best strategy to achieve high therapeutic efficacy. Two tuberculosis drugs, namely rifampicin and levofloxacin, which have different mechanism of action on the bacteria, were complexed with cyclodextrin and conjugated to curdlan nanoparticles, to achieve simultaneous sustained release of both the drugs over a prolonged period of time. They are non-cytotoxic to both RAW 264.7 and L929 cells. They are taken up ˜1.8 times more by the macrophage cells through dectin-1 receptor than the fibroblast cells. They are also able to kill more than 95% of Mycobacterium smegmatis residing within the macrophages in 4 h. These results demonstrate that curdlan-CD nanoparticles can be a promising system for the loading and intracellular release of hydrophobic drugs into macrophages for various therapeutic applications.

Host-guest supramolecular assembly directing beta-cyclodextrin based nanocrystals towards their robust performances.

Fluorescent CdTe nanocrystals (NCs) capped with beta-cyclodextrin (ß-CD) are successfully synthesized by host-guest supramolecular assembly of the hydrophobic alkyl chains of N-acetyl-l-cysteine (NAC) on the surface of CdTe NCs and eco-friendly ß-CD via the promising simple hydrothermal method in our experiments. The as-prepared NCs display better stability and lower toxicity compared with traditional those only capped with NAC. Specially, cytotoxicity experiments to human umbilical vein endothelial cells in vitro and zebrafish embryo toxicological tests in vivo are performed to determine the toxicity of CdTe NCs. For their practical applications, the promising red-luminescent NCs are employed as stable and low poison red phosphors to fabricate white light-emitting diodes (WLEDs) with remarkable color-rendering index (CRI) being 91.6. This research offers significance for solving the difficulty in toxicity and instability of heavy metal based NCs, which has potential applications in future optoelectronic devices and biomarkers.

ß-cyclodextrin based dual-responsive multifunctional nanotheranostics for cancer cell targeting and dual drug delivery.

Multifunctional nanoconjugates possessing an assortment of key functionalities such as magnetism, florescence, cell-targeting, pH and thermo-responsive features were developed for dual drug delivery. The novelty lies in careful conjugation of each of the functionality with magnetic Fe3O4 nanoparticles by virtue of urethane linkages instead of silica in a simple one pot synthesis. Further ß-cyclodextrin (CD) was utilized to carry hydrophobic as well as hydrophilic drug. Superlative release of DOX could be obtained under acidic pH conditions and elevated temperature, which coincides with the tumor microenvironment. Mathematical modelling studies revealed that the drug release kinetics followed diffusion mechanism for both hydrophobic drug and hydrophilic drug. A number of fluorophores onto a single nanoparticle produced a strong fluorescence signal to optically track the nanoconjugates. Enhanced internalization due to folate specificity could be observed by fluorescence imaging. Further their accumulation driven by magnet near tumor site led to magnetic hyperthermia. in vitro studies confirmed the nontoxicity and hemocompatibility of the nanoconjugates. Remarkable cell death was observed with drug-loaded nanoconjugates at very low concentrations in cancer cells. The internalization and cellular uptake of poor bioavailable anticancer agent curcumin were found to be remarkably enhanced on dosing the drug loaded nanoconjugates as compared to free curcumin. Site specific drug delivery due to folate conjugation and subsequent significant suppression in tumor growth was demonstrated by in vivo studies.

Self-Assembled Supramolecular Nanoparticles for Targeted Delivery and Combination Chemotherapy.

It is challenging but imperative to merge imaging agents and small molecule therapeutics into one nanoentity for diagnosis and treatment. Herein, we constructed polymeric nanoparticles for targeted delivery and combination chemotherapy, which formed through host-guest interactions among three elements: 1) ß-cyclodextrin polymer (poly-ß-CD), as the backbone of nanoparticles; 2) two antitumor drugs-doxorubicin (DOX) and docetaxel (DTX); and 3) aptamers labeled with adamantane and fluorescein (Ad-aptamer-FAM), as recognition elements. First, polymeric nanoparticles, termed self-assembled supramolecular nanoparticles (SSNPs), were formulated by combining hydrophobic DTX and DOX with poly-ß-CD via host-guest interactions. Then, the surface of SSNPs modified the aptamer to acquire targeting ability; such nanoparticles were termed targeted self-assembled supramolecular nanoparticles (T-SSNPs). As evidenced by MTS assay data, T-SSNPs exhibited significant selective cytotoxicity toward target cells. The results also indicated that combination drugs achieved a good synergistic effect with a combination index of 0.43. Thus, an effective and simple drug delivery system was constructed for targeted delivery and combination chemotherapy.

Physicochemical and Toxic Properties of Novel Genipin Drug Delivery Systems Prepared by Mechanochemistry.

BACKGROUND: Complexes of Genipin and different water-soluble adjuvant polysaccharides, such as arabinogalactane, hydroxyethyl starch, fibergum, and oligosaccharides ß-CD and HP-ß-CD, were synthesized as drug delivery system using mechanochemical technology. METHOD: We have investigated physicochemical properties, stability, and hepatotoxicity of the synthesized complexes in solid state and aqueous solution. The formation of the complexes was evidenced by different physical and spectroscopy assays, and the stability constants of our synthesized Genipin-based complexes were also calculated. RESULTS: The HP-ß-CD inclusion complex showed the highest characteristics. We have found that the molecule of Genipin was completely included in the cyclodextrin cavity of the HP-ß-CD. This complex of Genipin has shown a 6.14-fold increase of solubility compared with the original Genipin, and more stable in solvent and solid states. CONCLUSION: The hepatotoxicity assays showed that our investigated complexes of Genipin are much safer than the original Genipin. These results suggest that new Genipin-based preparations can be synthesized with advantageous of higher stability and safety.

Polymeric Nanoparticles Induce NLRP3 Inflammasome Activation and Promote Breast Cancer Metastasis.

Polymeric nanoparticles gain enormous interests in cancer therapy. Polyethylenimine (PEI) 25 kD is well known for its high transfection efficiency and cytotoxicity. PEI-CyD (PC) was previously synthesized by conjugating low molecular PEI (M w 600) with ß-cyclodextrin (ß-CyD), which is shown to induce lower cytotoxicity than PEI 25 kD. In the current study, the in vivo immune response of branched PEI 25 kD and PC is investigated. Compared to PC/pDNA, exposure of PEI 25kD/pDNA induces higher level of immune-stimulation evidenced by the increased spleen weight, phagocytic capacity of peritoneal macrophage, and proinflammatory cytokines in serum and liver. Importantly, administration of PEI 25 kD can greatly promote breast cancer metastasis in liver and lung tissues, which correlates with its ability to induce high oxidative stress and NLRP3-inflammasome activation. These results suggest that polymeric nanocarriers have the potential to induce immune-stimulation and cancer metastasis, which may affect their efficiency for cancer therapy.

Sensitive complex micelles based on host-guest recognition from chitosan-graft-ß-cyclodextrin for drug release.

In this paper, pH-sensitive complex micelles were developed based on the host-guest recognition from chitosan-graft-ß-cyclodextrin (CS-g-CD) and benzimidazole-terminated poly(ε-caprolactone) (BM-PCL) for controlled drug release. The formation and characterization of complex micelles were confirmed by fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and laser particle analyzer. The size of complex micelles was about 200nm with the core formed by BM-PCL/ß-CD and the shell composed of chitosan. Doxorubicin (DOX), a model anticancer drug, was effectively loaded into the complex micelles via hydrophobic interactions. The encapsulation efficiency of DOX was up to 75%. The release of DOX from complex micelles was suppressed at neutral pH solutions due to the stability of micelles but accelerated at acidic solutions and high temperatures. These sensitive complex micelles might possess potential applications as intelligent nanocarriers for anticancer drug delivery.

Supramolecular assemblies of histidinylated ß-cyclodextrin for enhanced oligopeptide delivery into osteoclast precursors.

Much attention has been given to the problem of drug delivery through the cell membrane in order to treat and manage bone diseases recently. The aim of this study was to develop nanoparticles made of amino- and histidinyl-modified amphiphilic ß-cyclodextrins (ß-CDs) entrapping osteoclast inhibitor, a hydrophobic oligopeptides drug, across the membrane of bone marrow-derived macrophages (BMMs). Drug-loaded ß-CDs nanoparticles (NPs) were prepared by the emulsion solvent evaporation technique and fully characterized for size, zeta potential, and entrapment efficiency. Spherical NPs displaying a hydrodynamic radius of about 295 nm which did not change upon storage as an aqueous dispersion, a positive zeta potential, and entrapment efficiency of drug very close to 98% were produced. Flow cytometry and spectrofluorimetry analysis indicated that the model drug itself was not taken up by the BMMs; however, NP systems underwent significant cellular uptake. In particular, histidinyl group-modified CD (ß-CD-H) NPs were taken up more efficiently than amino group-modified (ß-CD-A) ones. Cellular uptake mechanism study demonstrated that the permeability of drug-loaded NPs across the membrane of BMMs is probably due to macropinocytosis pathway. Cell viability studies showed that both ß-CD-A and ß-CD-H exhibited no significant cytotoxicity up to 1.0 mg/ml against the cells. These results highlight the developed ß-CD-H NPs have great potential in safely and effectively delivering osteoclast inhibitors and other therapeutic agents toward bone disease.

2-Hydroxypropyl-ß-Cyclodextrin Acts as a Novel Anticancer Agent.

2-Hydroxypropyl-ß-cyclodextrin (HP-ß-CyD) is a cyclic oligosaccharide that is widely used as an enabling excipient in pharmaceutical formulations, but also as a cholesterol modifier. HP-ß-CyD has recently been approved for the treatment of Niemann-Pick Type C disease, a lysosomal lipid storage disorder, and is used in clinical practice. Since cholesterol accumulation and/or dysregulated cholesterol metabolism has been described in various malignancies, including leukemia, we hypothesized that HP-ß-CyD itself might have anticancer effects. This study provides evidence that HP-ß-CyD inhibits leukemic cell proliferation at physiologically available doses. First, we identified the potency of HP-ß-CyD in vitro against various leukemic cell lines derived from acute myeloid leukemia (AML), acute lymphoblastic leukemia and chronic myeloid leukemia (CML). HP-ß-CyD treatment reduced intracellular cholesterol resulting in significant leukemic cell growth inhibition through G2/M cell-cycle arrest and apoptosis. Intraperitoneal injection of HP-ß-CyD significantly improved survival in leukemia mouse models. Importantly, HP-ß-CyD also showed anticancer effects against CML cells expressing a T315I BCR-ABL mutation (that confers resistance to most ABL tyrosine kinase inhibitors), and hypoxia-adapted CML cells that have characteristics of leukemic stem cells. In addition, colony forming ability of human primary AML and CML cells was inhibited by HP-ß-CyD. Systemic administration of HP-ß-CyD to mice had no significant adverse effects. These data suggest that HP-ß-CyD is a promising anticancer agent regardless of disease or cellular characteristics.

Physically cross-linked hydrogels of ß -cyclodextrin polymer and poly(ethylene glycol)-cholesterol as delivery systems for macromolecules and small drug molecules.

An injectable hydrogel based on the inclusion complexation of polymerized ß-cyclodextrin (pß-CD) and cholesterol terminated poly(ethylene glycol) (PEG-chol) was developed and used as a delivery system for both macromolecules and small drugs. The hydrogel was characterized by different analyses including X-ray diffraction, differential scanning calorimetry and scanning electron microscopy. The effects of pß-CD/PEG-chol ratio and PEG-chol architecture on the hydrogel properties were also investigated. Cytotoxicity of the hydrogel was evaluated in NIH 3T3 fibroblasts using MTS assay. The hydrogel had an elastic behavior even at high temperature since the gelation temperature was observed at 68 °C. The highest hydrogel strength and stability were observed for the 8-armed PEG-chol at a pß-CD/PEG-chol ratio of 1:1, w/w. Hydrogel degradation in phosphate buffered saline occurred by gradual erosion over the course of two months. IgG, a model hydrophilic macromolecule and riluzole, a model hydrophobic small drug were incorporated into the hydrogel and quantitatively released in a sustained fashion. The released IgG maintained its bioactivity confirming the absence of deleterious effects on protein structure during loading and release. The hydrogels showed no toxicity on NIH 3T3 fibroblasts confirming their biocompatibility. These results confirm the potential of pß-CD/PEG-chol hydrogel as a versatile delivery system for drugs of different molecular weights and nature.

A medusa-like ß-cyclodextrin with 1-methyl-2-(2'-carboxyethyl) maleic anhydrides, a potential carrier for pH-sensitive drug delivery.

We developed a new pH-sensitive drug delivery carrier based on ß-cyclodextrin (ß-CD) and 1-methyl-2-(2'-carboxyethyl) maleic anhydrides (MCM). The primary hydroxyl groups of ß-CD were successfully attached to MCM residues to produce a medusa-like ß-CD-MCM. The MCM residue was conjugated with cephradine (CP) with high efficiency ( > 90%). More importantly, ß-CD-MCM-CP responded to the small pH drop from 7.4 to 5.5 and released greater than 80% of the drugs within 0.5 h at pH 5.5. In addition, the inclusion complex between ß-CD-MCM-CP and the adamantane derivative was formed by simple mixing to show the possibility of introducing multi-functionality. Based on these results, ß-CD-MCM can target weakly acidic tissues or organelles, such as tumours, inflammatory tissues, abscesses or endosomes, and be easily modified with various functional moieties, such as ligands for cell binding or penetration, enabling more efficient and specific drug delivery.

Budesonide/cyclodextrin complex-loaded lyophilized microparticles for intranasal application.

OBJECTIVE: Lyophilized microparticles composed of budesonide (BDS), hydroxypropyl-ß-cyclodextrin (HP-ß-CD), and hydroxypropylmethylcellulose (HPMC) or sodium carboxymethylcellulose (CMC-Na) were developed for intranasal delivery and their characteristics were evaluated. MATERIALS AND METHODS: The particle size and morphology were assessed by mean diameter measurement and scanning electron microscopy (SEM) image, respectively. The solid-state of products was tested by X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). In vitro drug release and cytotoxicity to the primary human nasal epithelial (HNE) cells were also evaluated. RESULTS AND DISCUSSION: Lyophilized microparticles exhibited vanishment of crystallinity of drug in XRPD analysis, the enfeeblement of carbonyl (C=O) stretching bands of carboxyl group in BDS in FT-IR spectra and the disappearance of endothermic peak of drug in the results of DSC study. Based on the results of solid-state studies, BDS was existed as an amorphous form in the lyophilized microparticles. CD complexation enhanced drug solubility and release rate, and HPMC or CMC-Na also improved drug dissolution rates. Cytotoxicity of developed microparticles to the HNE cells was measured and their safety to HNE cell was identified. CONCLUSION: Developed microparticles can efficiently deliver insoluble drug, such as BDS, to the nasal epithelium and thus it may improve therapeutic efficacy in the respiratory tract.

Polyethylenimine600-ß-cyclodextrin: a promising nanopolymer for nonviral gene delivery of primary mesenchymal stem cells.

Genetically modified mesenchymal stem cells (MSCs) have great potential in the application of regenerative medicine and molecular therapy. In the present manuscript, we introduce a nanopolymer, polyethylenimine600-ß-cyclodextrin (PEI600-ß-CyD), as an efficient polyplex-forming plasmid delivery agent with low toxicity and ideal transfection efficiency on primary MSCs. PEI600-ß-CyD causes significantly less cytotoxicity and apoptosis on MSCs than 25 kDa high-molecular-weight PEI (PEI25kDa). PEI600-ß-CyD also exhibits similar transfection efficiency as PEI25kDa on MSCs, which is higher than that of PEI600Da. Quantum dot-labeled plasmids show that PEI600-ß-CyD or PEI25kDa delivers the plasmids in a more scattered manner than PEI600Da does. Further study shows that PEI600-ß-CyD and PEI25kDa are more capable of delivering plasmids into the cell lysosome and nucleus than PEI600Da, which correlates well with the results of their transfection-efficiency assay. Moreover, among the three vectors, PEI600-ß-CyD has the most capacity of enhancing the alkaline phosphatase activity of MSCs by transfecting bone morphogenetic protein 2, 7, or special AT-rich sequence-binding protein 2. These results clearly indicate that PEI600-ß-CyD is a safe and effective candidate for the nonviral gene delivery of MSCs because of its ideal inclusion ability and proton sponge effect, and the application of this nanopolymer warrants further investigation.

Efficient gene transfection in the neurotypic cells by star-shaped polymer consisting of ß-cyclodextrin core and poly(amidoamine) dendron arms.

In order to develop the effective vectors that had high gene transfection capability and low cytotoxicity in the neuronal cells, we tested the star-shaped polymer consisting of ß-cyclodextrin core and poly(amidoamine) (PAMAM) dendron arms [ß-CD-(D3)7] as the vector to transfect the human neuroblastoma SH-SY5Y cells. The physicochemical properties of the ß-CD-(D3)7/plasmid DNA (pDNA) complexes were characterized by using gel electrophoresis, dynamic light scattering, transmission electron microscopy and zeta-potential experiments. Among the human neuroblastoma SH-SY5Y cells, ß-CD-(D3)7/pDNA complex demonstrated a lower toxicity compared to those of PAMAM (G=4, with an ethylenediamine core)/pDNA complex. When the N/P ratio was over 20, it was observed that PAMAM had a faster increment in toxicity compared to ß-CD-(D3)7. Fluorescent image, confocal microscopy image and flow cytometry showed that ß-CD-(D3)7/pDNA complexes had significantly higher transgene activity than that of PAMAM/pDNA complexes. For example, the transfection efficiency was 20% and 7.5% for ß-CD-(D3)7/pDNA and PAMAM/pDNA complexes, respectively. These results indicated that ß-CD-(D3)7 might be a promising candidate for neurotypic cells gene delivery with the characteristics of good biocompatibility, relatively high gene transfection capability and potential in vivo gene delivery ability.

Effect of 6-O-α-maltosyl-ß cyclodextrin and its cholesterol inclusion complex on cellular cholesterol levels and ABCA1 and ABCG1 expression in mouse mastocytoma P-815 cells.

We have previously described 6-O-α-maltosyl-ß cyclodextrin (Mal-ßCD), which forms soluble inclusion complex with cholesterol. Here we further investigated the effect of Mal-ßCD and cholesterol/Mal-ßCD inclusion complex (CLM) on cellular cholesterol levels in a mouse mast cell line, mastocytoma P-815 cells (P-815 cells). Mal-ßCD removes cellular cholesterol forming inclusion complexes, while Mal-ßCD-induced lack of cellular cholesterol was replenished by the addition of CLM without cytotoxicity. Reduction and replenishment of cellular cholesterol in Mal-ßCD- and/or CLM-treated P-815 cells, respectively, were demonstrated by LC/MS and fluorescence microscopy with filipin III. CLM rather than free Mal-ßCD and free cholesterol was efficiently incorporated into P-815 cells and its incorporation was inhibited by incubation at low temperature, or with sodium azide and cytochalasin D. P-815 cells have been confirmed to express ATP-binding cassette (ABC) transporters, ABCA1, ABCG1, and P-glycoprotein (P-gp), by Western blot and mRNA analysis. Cholesterol reduction by Mal-ßCD abolishes the mRNA and protein expression of ABCA1 and ABCG1, but not of P-gp. Cholesterol loading by CLM restores the diminished ABCA1 and ABCG1 mRNA expression in Mal-ßCD-treated P-815 cells. However, both Mal-ßCD and CLM had no effect on P-gp activity measured by the rhodamine 123 efflux assay. These results indicate that alteration of cholesterol levels with Mal-ßCD or CLM led to down- or up-regulation of ABCA1 and ABCG1 expression in P-815 cells.

Development of a low toxicity, effective pDNA vector based on noncovalent assembly of bioresponsive amino-ß-cyclodextrin:adamantane-poly(vinyl alcohol)-poly(ethylene glycol) transfection complexes.

A host:guest-derived gene delivery vector has been developed, based on the self-assembly of cationic ß-CD derivatives with a poly(vinyl alcohol) (MW 27 kDa) (PVA) main chain polymer bearing poly(ethylene glycol) (MW 750) (PEG) or MW 2000 PEG and acid-labile adamantane-modified (Ad) grafts through an acid-sensitive benzylidene acetal linkage. These components were investigated for their ability to promote supramolecular complex formation with pDNA using two different assembly schemes, involving either precomplexation of the pendent Ad-PVA-PEG polymer with the cationic ß-CD derivatives before pDNA condensation (method A) or pDNA condensation with the cationic ß-CD derivatives prior to addition of Ad-PVA-PEG to engage host:guest complexation (method B). The pendent polymers were observed to degrade under acidic conditions while remaining intact for more than 5 days at pH 7. HeLa cell culture data show that these materials have 10(3)-fold lower cytotoxicities than 25 kDa bPEI while maintaining transfection efficiencies that are superior to those observed for this benchmark cationic polymer transfection reagent when the method A assembly scheme is employed. These findings suggest that degradable cationic polymer constructs employing multivalent host:guest interactions may be an effective and low-toxicity vehicle for delivering nucleic acid cargo to target cells.