Nano-sized Complexes Research Articles

Synthesis and spectral behavior of nanometric Ti(IV) complexes with nitrogen, sulfur, and oxygen donors

To study the spectral behavior of Ti(IV) complexes with sulfur donors, several new nano-sized mixed ligand complexes of Ti(IV) have been synthesized by the reaction of titanium(IV) salts with 3(2′-hydroxyl phenyl)-5-(4-substituted phenyl)pyrazolines and ammonium salts of dithiophosphates. Spectroscopic and X-ray diffraction studies reveal amorphous and monomeric complexes. The Ti(IV) complexes show octahedral geometry in which dithiophosphate and pyrazoline are bidentate. Transmission electron microscopic image shows that the particle size ranges from 50 to 90 nm.

Layer-by-layer chemical deposition technique for thin film assembly of deposited nano-sized magnesium(II)–5,7-dinitro-8-hydroxyquinolate: Characterization and spectral–optical–electrical properties

Layer-by-layer (LBL) chemical deposition technique was implemented as a low cost and efficient methodology for rapid synthesis and assembly of deposited thin films of nano-sized magnesium(II)–5,7-dinitro-8-hydroxyquinolate complex, Mg[(( NO 2) 2- 8HQ) 2]. The stoichiometry of deposited nano-sized complex was characterized as a 1:2 ratio based on metal to ligand without contribution of the nitro-group. Further structural characterization and identification were also monitored by using Fourier Transform infrared spectroscopy (FT-IR) in order to confirm the possible mode of bonding in the deposited nano-sized Mg[(( NO 2) 2- 8HQ) 2] complex. Thermal gravimetric analysis (TGA) of the ligand and complex were studied and compared to evaluate the possible incorporated thermal stability characteristics. Surface imaging of assembled thin film was performed by using scanning electron microscopy (SEM) to confirm high homogeneity in surface particles distribution with average particle size in the range of 30–50 nm. The absorption spectrum of Mg[(( NO 2) 2- 8HQ) 2] thin film was recorded in the spectral region 250–1000 nm. The optical transmission and reflection spectra of the films have been recorded within the wavelength range 250–2500 nm. The optical parameters of the films, such as absorption index, α, refractive index, n, band gap, E g , dielectric constants, ε 1 and ε 2 and dissipation factor, tan δ, have been also determined. Two activation energies were determined from the temperature dependence of the dark electrical conductivity. Hopping conduction parameters of Mg[(( NO 2) 2- 8HQ) 2] have been calculated by employing the variable range hopping model.

Synthesis, Spectroscopic Studies, Crystal Structure and Electrochemical Properties of New Cobalt(III) Complex Derived from 2-Aminophenol and 4-(Dimethylamino)Cinnamaldehyde: Nano-Sized Complex Thin Film Formation via Surface Layer-by-Layer Chemical Deposition Method

New Schiff base (HL) ligand is prepared via condensation of 2-aminophenol and 4-(dimethylamino) cinnamaldehyde. The cobalt complex with the formula of [Co(L)2(MePy)2]PF6 is prepared in good yield from the reaction of the ligand with cobalt(II) acetate. The compounds were characterized by the analytical and spectroscopic methods. The ligand (HL) behaves as a bidentate ligand and coordinates to the cobalt ions via the nitrogen and oxygen atoms with mononuclear structure. The ligand (HL) has been structurally characterized by X-ray crystallography. There is O–H···N–H bond linking the molecules together. FT-IR spectra show that HL is coordinated to the cobalt ion in a mono-negative bidentate manner with ON donor sites of the azomethene N and deprotonated phenolic-OH. There are two methylpyridine molecules apically coordinated to Co(III) ion in octahedral environment. Electrochemical properties were investigated as metal centres in the dimethylformamide solvents. The Co(III) complex exhibit both irreversible reductive (CoIII/CoII; Epc, −1.24 V) and oxidative (CoII/CoIII; Epa, +0.79 V, respectively) responses in cyclic voltammetry. Thin film of nano-sized [M(L)2(MePy)2]PF6 complex was formed by surface layer-by-layer chemical deposition method. The formation of uniform thin films of nano-crystalline metal complex is dependent on metal and ligand concentrations.

Structure and elastic property of nanosized complex oxide particles in ferritic/martensitic alloy: An electron energy-loss spectroscopy study

The structure and elastic property of nanosized complex oxide particles in a ferritic/martensitic alloy containing titanium and silicon were studied by transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS). The nanosized complex Y–Si–O particles were found in the matrix of the alloy in addition to Y–Ti–O, and the size of Y–Si–O is smaller than that of Y–Ti–O particles. The formation of Y 2.16Si 1.76O 7 and Y 2.15Ti 1.95O 7 were further confirmed by O K, Si L 2,3 and Ti L 2,3 edges, respectively. The bulk modulus of Y 2.16Si 1.76O 7 was shown to be lower than that of Y 2.15Ti 1.95O 7, which implies that the nanosized Y 2.16Si 1.76O 7 particles would provide more effective dislocation pinning at elevated temperatures.

Chitosan‐Functionalized Graphene Oxide as a Nanocarrier for Drug and Gene Delivery

The covalent functionalization of graphene oxide (GO) with chitosan (CS) is successfully accomplished via a facile amidation process. The CS-grafted GO (GO-CS) sheets consist of about 64 wt.% CS, which imparts them with a good aqueous solubility and biocompatibility. Additionally, the physicochemical properties of GO-CS are studied. As a novel nanocarrier, GO-CS is applied to load a water-insoluble anticancer drug, camptothecin (CPT), via π-π stacking and hydrophobic interactions. It is demonstrated that GO-CS possesses a superior loading capacity for CPT, and the GO-CS-CPT complexes show remarkably high cytotoxicity in HepG2 and HeLa cell lines compared to the pure drug. At the same time, GO-CS is also able to condense plasmid DNA into stable, nanosized complexes, and the resulting GO-CS/pDNA nanoparticles exhibit reasonable transfection efficiency in HeLa cells at certain nitrogen/phosphate ratios. Therefore, the GO-CS nanocarrier is able to load and deliver both anticancer drugs and genes.

Synthesis and Characterization of ZnO Nanoparticles via Thermal Decomposition of Two Zinc(II) Supramolecular Compounds

A new nano-sized Zn(II) complex, [Zn(5,5′-dtbu-2,2′-bipy)Cl2] n (1) was synthesized and its structure determined by X-ray crystallography. The new nano-sized complex was prepared at oleic acid as a surfactant at 280 °C and characterized by scanning electron microscopy, elemental analyses and IR spectroscopy. The ZnO nano-particles were synthesized from thermolysis of nano-compound 1 at 600 °C and similar compound, [Zn(5,5′-dimethyl-2,2′-bipy)Cl2] n (2), at two different methods. SEM images show the average size of ZnO nano-particles are 78 and 50 nm for the compounds 1 and 2, respectively.

Photoluminescent nano-sized ternary and quaternary complexes of thorium(IV)

Abstract Some ternary and quaternary complexes of thorium(IV) with the general formula [Th(OOCCH3)2−n (SB) n (OOCC15H31)2] (HSB=Schiff bases and n=1 or 2) have been synthesized by the stepwise substitutions of acetate ions from thorium(IV) acetate, first with straight chain carboxylic acid and then with Schiff bases. The complexes are characterized by elemental analyses, spectral (electronic, infrared, 1H NMR, FAB mass, photoluminescence and powder XRD) and TEM studies. Conductance measurements indicated non-conducting behaviour of the complexes. Structural parameters from powder XRD data for complexes 5 and 6 which indicate poorly crystalline nano-sized triclinic particles. Electronic absorption spectra of the complexes showed π→π * and n→π * charge transfer transitions. All complexes displayed fluorescence and a correlation was sought between luminescence spectra of complexes in solution at room temperature. On the basis of physico-chemical studies, coordination number 8 was assigned for thorium(IV) in the complexes. The morphology and microstructure of the complexes were examined with transmission electron microscopy (TEM) and the selected area electron diffraction (SAED).

Preparation and Characterization of Ternary Europium Nanorod Complexes with UV Excitation of the Characteristic Red Luminescence

Rare-earth luminescent complex have been attracted increasing interest since they can emit fluorescence using near ultraviolet as excitation wavelength. Nanomaterials have potential applications in optical, electronic, magnetic fields due to their surface effects, volume effects, quantum size effects and macroscopic quantum tunnel effects. Combing the important properties of fluorescence and nanomaterial, the study of nanosized rare earth fluorescence complex is an interesting topic. In this paper, we synthesized ternary luminescence complex nanorods composed of europium (Eu (III))-trimesic acid (H3L)-1,10-phenanthroline (phen) using co-precipitation method in the polyvinylpyrrolidone (PVP) matrix. The elemental analyses of the samples were determined using an Inductively coupled plasma atomic emission spectroscopy (ICP-AES), and the chemical composition PVP/EuL(phen)0.2 5H2O was obtained. The X-ray diffraction (XRD) patterns showed that the resulting nano-sized complex is new substance different from that of two ligands. The transmission electron microscopy (TEM) image indicated that the nano-sized complex was nanorod with the average diameter of about 50 nm. Thermal analysis (TGA) result exhibited that the nano-sized complex is stable under 400 degrees C. UV-Vis diffuse reflectance spectra (DRS) showed that there is the maximum absorption at 260 nm. Photoluminescence analysis (PLA) indicated that the nano-sized complex emits Eu (III) characteristic red luminescence under ultraviolet excitation.

The Effect of Ti-Zr Deoxidation on the Mechanical Properties of High Strength Low Alloy Steels

The uniformity of the mechanical properties, especially elongation and impact toughness, were compared between steel A, which was deoxidized with Ti-Zr, and steel B, which was deoxidized with Al. Microstructural observations, energy dispersive X-ray spectroscopy and X-ray diffraction analyses were conducted using an optical microscope, a scanning electron microscope and a transmission electron microscope, respectively. Results showed that sub-micron and nano-sized complex oxides were obtained by the combined deoxidation of Ti-Zr. The stability of the mechanical properties of steel A was better than that of steel B. The elongation and impact toughness of steel A were enhanced relative to those of steel B. This was attributed to spheroidization and the dispersed distribution of MnS inclusions in the matrix of steel A.

Ionic complex systems based on hyaluronic acid and PEGylated TNF-related apoptosis-inducing ligand for treatment of rheumatoid arthritis

The clinical applications of tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL), an emerging therapeutic protein for cancer and rheumatoid arthritis (RA), are limited by its instability and short biological half-life. In this study, efficient therapeutic modalities for RA treatment were developed in the form of nano-sized complexes (nanocomplexes) based on hyaluronic acid (HA) and polyethylene glycol (PEG)–derivatized TRAIL (PEG–TRAIL) formed by N-terminal specific PEGylation. The nanocomplexes were prepared by simply mixing the positively charged PEG–TRAIL and negatively charged HA, and showed negligible loss of bioactivity compared with the PEG–TRAIL. The in vivo biodistribution and diffusion kinetics of Cy5.5-labeled PEG–TRAIL in mice were observed using a near-infrared optical imaging system after subcutaneous injection of three different formulations: PEG–TRAIL in phosphate–buffered saline (PBS, pH 7.4), nanocomplex in PBS, or nanocomplex in 1% HA solution. The results suggested that PEG–TRAIL is released slowly in vivo from the nanocomplex in 1% HA. Experiments in a collagen-induced arthritis mouse model demonstrated that the magnitudes of therapeutic effects, as judged by clinical scores and histology, were significantly enhanced by the sustained delivery of PEG–TRAIL, with the order of nanocomplex in 1% HA > nanocomplex in PBS > PEG–TRAIL in PBS. In addition, sustained delivery of PEG–TRAIL from the nanocomplex in 1% HA resulted in significant reduction of serum inflammatory cytokines and collagen-specific antibodies that are responsible for the pathogenesis of RA. These results imply that HA/PEG–TRAIL nanocomplex formulations are promising therapeutic modalities for the treatment of RA.

Evaluation of succinylated pullulan for long-term protein delivery in poly(lactide-co-glycolide) microspheres

Two types of pullulan with different succinylations were synthesized for an evaluation as additives for long-term protein delivery in poly(lactide-co-glycolide) microspheres (PLGA MS). Negatively charged succinylated pullulan (SP) forms an ionic complex with cationic protein (lysozyme; Lys) via an ionic interaction. SP2 (2 succinyl groups per 10 glucose units in pullulan) constructed a better nano-size complex with lysozyme (Lys) in distilled water (DW) than SP1 (1 succinyl group per 10 glucose units in pullulan). To assess the long-term delivery capability, PLGA MS complexes with different Lys:SP2 ratios (1:1 (LMS 1), 1:2 (LMS 2) and 1:3 (LMS 3), as wt% of Lys:SP2) were prepared with water in oil in water (W/O/W). The complex loaded PLGA MS showed a higher loading efficiency and a lower insoluble Lys content than PLGA without SP (LMS 0), indicating that SP helps stabilize Lys at the organic/water (O/W) interface. In evaluating the release pattern of Lys, LMS 1, 2, and 3 all demonstrated a low initial burst and complete release behavior (reaching almost 100% after 27 days), whereas the total amount of Lys released from LMS 0 did not reach 80% during the same time period. During a 14-day release test, the stability of Lys was confirmed by RP-HPLC. In the case of LMS 0, an unexpected peak (retention time 9.2 min) was created, which was not observed in LMS 1, 2, and 3. This suggests that SP suppresses the denaturation of Lys in PLGA MS. These results show that SP, as an additive in PLGA MS, has potential for the long-term delivery of therapeutic proteins. Open image in new window

ChemInform Abstract: Characterization of Self-Assembling Nano-Sized Structures by Means of Coldspray Ionization Mass Spectrometry.

Abstract Coldspray ionization (CSI) for mass spectrometry (MS) has been developed and applied to characterize labile self-assembling nano-sized metal complexes. While conventional ESI-MS is not applicable to these compounds because of their instability, CSI affords multiply charged molecular ions with many solvent (acetonitrile) molecules attached. We measured the exact mass of these molecular ions by using crown ether compounds as internal standards. Highly concentrated solutions (ca. 1 mmol/L) of the complexes, whose framework constitution is strongly influenced by concentration, could be used. In the case of some aqueous solutions, the molecular ions could be clearly observed by adjusting the temperature of the desolvation chamber to near the freezing point of water. This CSI-MS should be applicable to a wide variety of labile ionic compounds.

Nanosized Dendritic Polyguanidilyated Translocators for Enhanced Solubility, Permeability, and Delivery of Gatifloxacin

Dendrimeric polyguanidilyated translocators (DPTs) are nanosized novel dendrimers that efficiently translocate molecules across biological barriers. The purpose of this study was to develop a DPT that could serve as an ophthalmic delivery vehicle for gatifloxacin and to evaluate its in vitro and in vivo delivery after topical application. The gatifloxacin (GFX) solubility-enhancing property of a six-guanidine group-containing dendrimer (g6 DPT) was investigated as a function of pH and dendrimer concentration. Mechanisms of drug interaction with the dendrimer were investigated by using isothermal titration calorimetry (ITC), Fourier-transformed infrared spectroscopy (FTIR), and nuclear magnetic resonance spectroscopy (NMR). Permeability of the dendrimer was assessed in human corneal epithelial cells (HCECs) and across isolated bovine sclera-choroid-RPE (SCRPE). In vitro efficacy of the dendrimer formulation was evaluated with a time-to-kill assay for methicillin resistant Staphylococcus aureus (MRSA). In vivo delivery of GFX in a dendrimer eye drop formulation was studied in New Zealand White rabbits after a single dose or multiple doses over 3 weeks. Drug levels in various ocular tissues were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). An optimized DPT-GFX formulation (final pH 5.9, no preservative) increased GFX solubility by fourfold. The dendrimer formed isotonically stable, nanosized (346-nm) complexes with GFX via ionic bond, hydrogen bond, and hydrophobic interactions. The dendrimer gained rapid entry into the HCECs (within 5 minutes) and increased the transport of GFX by 40% across the SCRPE in 6 hours. DPT-GFX exhibited a three times faster killing rate for MRSA when compared with GFX alone. In vivo administration of DPT-GFX (1.2% wt/vol) resulted in ∼13-fold, and ∼2-fold higher areas under the curve (AUCs) for tissue concentrations in conjunctiva and cornea, respectively, when compared with GFX (0.3%) after a single dose. Further, a single dose of DPT-GFX sustained aqueous humor and vitreous humor drug levels during the 24-hour study, with a t(1/2) of 9 and 32 hours, respectively. After multiple doses, similar advantages were seen with DPT-GFX. The DPT forms stable complexes with GFX and enhances its solubility, permeability, anti-MRSA activity, and in vivo delivery, potentially allowing a once-daily dose regimen.

Template synthesis and characterization of diaza dioxa macrocyclic nanosized cobalt(II) complex dispersed within nanocavity of zeolite-Y

Nanocavity microreactor containing 15- and 16-membered diaza dioxa Schiff-base cobalt(II) complexes “[Co(Et[15]N 2O 2)] 2+, [Co(Pr[16]N 2O 2)] 2+, [Co(Ph[15]N 2O 2)] 2+ and [Co(Ch[15]N 2O 2)] 2+” have been prepared by the template synthesis of diamine (1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene or 1,2-diaminocyclohexane) with [(1,3-bis(2-carboxyaldehydephenoxy)propane)cobalt] 2+;[Co(BCAPP)] 2+@NaY within the pores of zeolite-Y. The nanosized cobalt(II) complex were entrapped in the supercage of Y-zeolite by a three-step process in the liquid phase: (i) exchange of Co(II) ions with NaY in water solution, (ii) reaction of Co(II)–NaY with excess BCAPP in methanol; [Co(BCAPP)] 2+@NaY; (iii) template synthesis of [Co(BCAPP)] 2+@NaY with diamine. The new nanosized complex entrapped in the nanocavity of zeolite Y was characterized by several techniques: chemical analysis and spectroscopic methods (FT-IR, UV–Vis, XRD, BET, DRS, XPS, TGA).

Preparation and characterization of super-hydrophobic and oleophobic surface

A novel method for preparing and characterizing super-hydrophobic and oleophobic surface is presented. Aluminum (Al) substrate was roughened by sandblasting and electrolytic etching to obtain micro- and nano-sized complex morphologies. Then, its substrate was covered by a chemically adsorbed monolayer (CAM) containing a fluorocarbon group. The surface of Al substrate roughened and covered with CAM was observed by scanning electron microscope and atomic force microscope. The roughnesses of the surface were ca. 100 μm and ca. 30–60 nm, respectively. The surface of the wettability was characterized by contact angle measurements and its surface indicated super-hydrophobicity and oleophobicity: the water contact angle (WCA) and oil contact angle (OCA) of hexadecane was 158.9° and 139.6°, respectively. The wettability was also characterized by solid surface energy. The solid surface energy of each solvent was obtained from the equation by Neumann et al. These values were extremely low, ranging from 0.31 to 1.29 mN/m. The total solid surface energy was obtained from the equation by Kaelble et al. The value was 0.3 mN/m. Their values indicated that the hydrophobicity and oleophobicity of our sample reached the highest level possible. In addition, our research demonstrates that it is easy to compare many different surfaces with super-hydrophobicity and oleophobicity using the solid surface energy.

Ascorbyl dipalmitate/PEG-lipid nanoparticles as a novel carrier for hydrophobic drugs

l-Ascorbyl 2,6-dipalmitate (ASC-DP), a fatty ester derivative of ascorbic acid, is poorly soluble in water and does not spontaneously form micelles or liposomal structures in water. In this study, we attempted to prepare an ASC-DP/surfactant nano-sized complex as a carrier for hydrophobic drugs. Samples were prepared by hydrating a solvent-evaporated film of ASC-DP/surfactant at a molar ratio of 1:1. Among the surfactants tested, distearoylphosphatidylethanolamine-polyethylene glycol 2000 (DSPE-PEG) was found to form stable nanoparticles with ASC-DP (average particle size: ca. 67 nm). Several hydrophobic drugs were incorporated in the ASC-DP/DSPE-PEG nanoparticles. Stability, toxicity, and blood residence of the drug-containing ASC-DP/DSPE-PEG nanoparticles were evaluated using amphotericin B (AmB) as the model drug. By intravenously administering mice with the formulations, we determined the minimum lethal dose of Fungizone ®, a formulation of AmB solubilized with sodium deoxycholate, was 3.0 mg/kg, while that of AmB/ASC-DP/DSPE-PEG nanoparticles was 10.0 mg/kg. When 2.0 mg/kg, Fungizone ® was administered, the mice showed higher renal and hepatic toxicities. Intravenously administered AmB/ASC-DP/DSPE-PEG nanoparticles demonstrated higher concentration in plasma than Fungizone ®. Thus, the ASC-DP/DSPE-PEG nanoparticle system appears to be a promising delivery system for hydrophobic drugs.

Stability and cellular uptake of polymerized siRNA (poly-siRNA)/polyethylenimine (PEI) complexes for efficient gene silencing

Small interfering RNA (siRNA) is a promising biological strategy for treatment of diverse diseases, but the therapeutic application of siRNA has been limited by its instability and poor cellular uptake efficiency. Although the development of various gene delivery systems has increased the siRNA delivery efficiency, many problems still remain to be resolved before the clinical application of siRNA. In this study, we suggest reducible polymerized siRNA a possible solution for low delivery efficiency of siRNA. Dithiol-modified red fluorescent protein (RFP) siRNAs at the 5′-ends of both sense and anti-sense strands were disulfide-polymerized. Polymerized siRNA (poly-siRNA) was composed of 30% oligomeric siRNA (50~300 bps) and 66% polymeric siRNA (above ~ 300 bps) as fractions, and was reducible in reducing solution through disulfide bond cleavage. Poly-siRNA formed more condensed and nano-sized complexes with low molecular weight polyethylenimine (PEI) by strong electrostatic interaction based on the higher charge density of poly-siRNA, compared with siRNA (mono-siRNA). The compact poly-siRNA/PEI complexes prevented the loss and degradation of siRNA from a polyanion competitor and RNases in serum. Furthermore, poly-siRNA/PEI complexes exhibited superior intracellular uptake by murine melanoma cells (B16F10), and was accompanied with RFP gene silencing efficiency of about 80%, compared to untreated cells. These results sufficiently support that strong polyanionic and reducible poly-siRNA can be utilized as a novel powerful therapeutic strategy for human diseases.

The characteristics and transfection efficiency of cationic poly (ester–co–urethane) – short chain PEI conjugates self-assembled with DNA

To improve the transfection efficiency of polycations with DNA, we synthesized poly(ester–co–urethane)(PEU-g-PEI800) with short chain PEI800 in the side chain, and poly(ester–co–urethane)(PEU) without short chain PEI800. Both PEU-g-PEI800 and PEU, readily self-assembled with plasmid DNA (pCMV-βgal) in a HEPES buffer, were characterized by dynamic light scattering and zeta-potential. The results reveal that PEU-g-PEI800 and PEU were able to self-assemble particles with DNA and yield nano-sized complexes (<200 nm) with positive charge at N/P ratios of 20/1 and 120/1, respectively. The degradation studies indicate that the half-life of PEU-g-PEI800 and PEU in the HEPES buffer were 14 and 35 h at pH 7.4, respectively. Titration studies were performed to determine the buffering capacities of the polymers. The COS-7 cell viabilities in the presence of PEU-g-PEI800/DNA, PEU/DNA, and PEI25k/DNA were studied. In addition, The PEU-g-PEI800/DNA complexes were able to transfect COS-7 cells in vitro with a high efficiency comparable to a well-known gene carrier PEI25k. The results indicate that PEU-g-PEI800 is an attractive cationic poly (ester–co–urethane) for gene delivery and an interesting candidate for further study.

In Vitro Characteristics of Heparin/Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand Nanocomplexes

In an attempt to improve the stability of tumor necrosis factor-related apoptosis inducing ligand (TRAIL), we prepared the nano-sized complexes by mixing the positively charged TRAIL with heparin, a highly sulfated polysaccharide. The increase in the feed ratio (FR) of heparin to TRAIL reduced the particle size and decreased the zeta-potential, indicating that the TRAIL surface was covered by heparin via the ionic interactions. TRAIL in the complexes was demonstrated to effectively induce apoptosis of the cancer cells. The results indicated that heparin is the useful, anionic polysaccharide as the carrier of TRAIL to form stable nano-sized complexes.

A novel nanometer non-viral gene transfer system for cartilage defects

Objective To develop a clinically applicable approach to enhance repair of cartilage defects by constructing an in vivo non-viral gene transfer system targeting chondrocytes. Methods High molecular weight chitosan (HMWC) was degraded to produce low molecular weight chitosan (LM-WC) that was combined with transforming growth factor-β1 (TGF-β1) plasmid to form stable nano-sizc complexes. After being tested in vitro firstly, these nano-size complexes were injected into the knee joint of New Zealand white rabbit models with full-thickness cartilage defects to detect their feasibility of delive-ring the growth factor gent in vivo. Results The results showed that LMWC/DNA nano-sizc comple-xes could deliver the gone into the cultured chondroeytes and cartilage tissue efficiently in vitro. When used in vivo, LMWC/TGF-β1 gene nano-size complexes could enhance the transfection efficiency and prolong the expression of TGF-β1 gone. In the animal models of articular osteechondral defect of rabbits, better healing and gentler degeneration could be observed in comparison with the control. Conclusion In vivo transfection of LMWC/TGF-β1 nano-size complexe is a safe and effective method to early promote the repair of osteochondral defects. Key words: Cartilage, articular; Wounds and injuries; Gene; Nanometer