OBJECTIVE

The lack of effective screening methods and systemic understanding of interaction mechanisms complicates the stabilizer selection process for nanocrystallization. This study focuses on the efficiency of stabilizers with various molecular compositions and structures to stabilize drug nanocrystals.

METHODS

Five structurally different polymers were chosen as stabilizers for indomethacin nanocrystals. The affinity of polymers onto drug surfaces was measured using surface plasmon resonance (SPR) and contact angle techniques. Nanosuspensions were prepared using the wet-ball milling technique and their physico-chemical properties were thoroughly characterized.

RESULTS

SPR and contact angle measurements correlated very well with each other and showed that the binding efficiency decreased in the order L64>> 17R4>> F68 ≈ T908 ≈ T1107, which is attributed to the reduced PPO/PEO ratio and different polymer structures. The electrostatic interactions between the protonated amine of poloxamines and ionized indomethacin enhanced neither the affinity nor the properties of nanosuspensions, such as particle size and physical stability.

CONCLUSIONS

A good stabilizer should have high binding efficiency, full coverage, and optimal hydrophobic/hydrophilic balance. A high affinity combined with short PEO chains (L64, 17R4) caused poor physical stability of nanosuspensions, whereas moderate binding efficiencies (F68, T908, T1107) with longer PEO chains produced physically stable nanosuspensions.

We proposed an approach to precisely control the density of tethered chains on solid substrates using PEO-b-PS and PLLA-b-PS. As the crystallization temperature Tx increased, the PEO or PLLA lamellar crystal thickness d(L) increased as well as the reduced tethering density sigma; of the PS chains. The onset of tethered PS chains overcrowding in solution occurs at sigma(*) approximately 3.7-3.8 as evidenced by an abrupt change in the slope between (d(L))(-1) and Tx. This results from the extra surface free energy created by the tethered chain that starts to affect the growth barrier of the crystalline blocks.

The rheological properties of aqueous polystyrene latex dispersions from three synthetic batches, with nearly the same z-average particle sizes, 400 nm, but varying degrees of polydispersity, 0.085, 0.301, and 0.485, respectively, were systematically investigated using steady-state shear and oscillatory shear measurements. The particles were sized with photon correlation spectroscopy and transmission electron microscopy and were stabilized sterically with PEO-PPO-PEO triblock copolymer (Synperonic F127). Results from steady-state shear measurements show that the viscosities of the systems exhibit shear-thinning behavior at high solid fractions. However, the degree of shear thinning depends on the breadth of particle size distribution, with the narrowest distribution suspension exhibiting the highest degree of shear thinning. The Herschel-Bulkley relationship best describes the flow curves. The relative viscosities as a function of volume fraction data were compared, and it was found that the broadest distribution suspension had the lowest viscosity for a given volume fraction. In addition, the data were fitted to the Krieger-Dougherty equation for hard spheres. A reasonable agreement of theory with experiment is observed, particularly and surprisingly for the very broad distribution. However, when the contribution to the volume due to the adsorbed polymer layer is considered, the agreement between experiment and theory becomes closer for all the suspensions, although the agreement for the broad distribution suspension is now worse. Fitting the Dougherty-Krieger theory to the experimental data based on our experimental maximum packing fractions gives very good agreement for all the systems studied. From oscillatory shear measurements, the moduli were obtained as a function of frequency at various latex volume fractions. The results show general change of the dispersions from viscous (G">> G') at low volume fractions (0.25-0.30) to moderately elastic (G'>> G") at moderately high volume fractions (0.41-0.45). The change at this concentration level is likely due to some compression and interpenetration of the stabilizing polymer chain at the periphery, indicating the dominance of the interparticle forces. Overall, the very broad distribution was found to have the lowest elastic modulus for a given volume fraction. Copyright 1999 Academic Press.

Vesicles prepared from block copolymers have been mooted for the encapsulation of water-soluble molecules. This is because the membranes of polymer vesicles have been shown to be more stable than those in vesicles formed from lipids, with the membrane properties being tuned by the length and nature of the hydrophobic block in the polymer. The generally accepted mechanisms of vesicle formation involve either wrap-up of a lamellar sheet or formation via a sequence of micelle to worm to disks to vesicles. These should lead to efficient encapsulation. Alternatively, a method involving phase separation followed by re-structuring has been recently suggested. Here, we show that this final mechanism holds for vesicles formed from a PEO-b-PDEAMA copolymer by a pH switch and that this mechanism leads to highly inefficient encapsulation on vesicle formation.

Nuclear genes affecting mitochondrial genome stability were screened in an Italian family presenting with autosomal dominant progressive external ophthalmoplegia (ad<em>PEO</em>) associated with multiple mitochondrial DNA (mtDNA) deletions. We report on a heterozygous c.907C>T (p.R303W) mutation found in the N-terminal domain of the human mitochondrial DNA helicase, Twinkle protein, in six members of a family, in which two individuals manifested late-onset <em>PEO</em> and morphological and molecular signs of mitochondrial dysfunction along with two carriers who are presently free of disease manifestation. We also investigated if the p.R303W mutation in <em>PEO</em>1 gene affected the relative copy number of mitochondrial DNA genomes.

The use of nonionic polymeric micelles orally to protect and deliver plasmid DNA in vivo was investigated. Parathyroid hormone (PTH)(1-34) gene (179 bp) was inserted into a human cytomegalovirus promoter (PCMV) and E. coli competent cells were used to amplify the cDNA. Polymeric micelle formations (100 microl) formed from PCMV-PTH(1-34) cDNA (7.2 microg/microl) and 6% (w/v) polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) was administered at 8-hr intervals for 48 hr and then at 8-hr intervals for 24 hr weekly for 3 weeks. Parathyroidectomized rats receiving 150 microl of EDTA (10 mM) before each dose of formation served as the study group; rats receiving drinking water, EDTA (10 mM), PCMV-PTH(1-34) cDNA and PCMV-PTH(1-34) cDNA plus EDTA at the same amount and time intervals served as the control groups. Serum levels of calcium and PTH(1-34) were measured weekly for 4 weeks. Immunohistochemical stain for PTH(1-34), reverse transcriptase polymerase chain reaction for PTH(1-34) mRNA and the relative density of PTH(1-34) mRNA were performed at 2 and 4 weeks after oral gene therapy in different organs. One third to three of five rats in the control groups died after parathyroidectomy. Serum levels of calcium and PTH(1-34) were higher in the study than in the control groups. In the study group, positive stain of PTH(1-34) and PTH(1-34) mRNA could be found in those organs. Relative densities of PTH(1-34) mRNA were higher in the study than in the drinking water group in different organs. Oral gene therapy can maintain calcium and PTH(1-34) levels in parathyroidectomized rats.

Homocentric ZnO nanobundles with pyramidlike and hexagonal prism shapes were synthesized in colloidal systems formed by PEO-PPO-PEO amphiphilic block copolymers. The prism- and pyramidlike ZnO crystals were produced by L64 and F68, respectively, which may be attributed to the different growth rates of various crystal facets. It was proposed that the two processes for crystallization, including nucleation and crystal growth, happened in the macromolecular micelles under hydrothermal conditions. The room-temperature photoluminescence spectra of the ZnO products showed sharp ultraviolet emission located around 390 nm originating from the radiative recombination of free excitons. The sharp emission, with a half-maximum of about 8 nm, gave a powerful attestation that the sample was of high crystal quality, which was consistent with the SEM and TEM observations. The single ultraviolet emission is important for the application of ZnO-based materials in the electronic and photonic realms.

A novel chemical modification of biological tissues was developed aimed at improving biocompatibility and calcification resistance. This method involved the additional grafting of sulfonated PEO (PEO-SO(3)) or heparin after conventional glutaraldehyde (GA) fixation of bovine pericardium (BP). The amino groups of PEO-SO(3) or heparin were utilized to react to the GA residues to block them. The PEO-SO(3) or heparin grafted tissues demonstrated a slightly higher shrinkage temperature and tensile strength, but greater resistance to collagenase digestion, than GA treated ones. These results suggest that modified tissues have improved durability due to the grafting and filling effect of PEO-SO(3) or heparin in addition to the GA cross-linking. At the direct contact cytotoxicity test in vitro, PEO-SO(3) or heparin grafted tissue was shown to be nontoxic, while relatively significant cytotoxicity was observed for the GA treated tissues, possibly due to the release of GA. From the in vivo calcification study, calcium contents deposited on the modified tissues were much less than those on GA treated tissues. Such a decreased calcification might be explained by the decrease of residual GA groups during the additional treatment, and the space-filling effect and the nonadhesive property and/or the blood compatibility of PEO-SO(3) or heparin grafted covalently. The newly modified tissue patch was observed to show improved pathological assessibility including less inflammation and tissue reactions. This simple modification method may be useful for calcification-resistant and blood-compatible tissue patches for cardiovascular implants.

A previous study of the present authors on gel-forming erodible inserts, based on high molecular weight (MW, 400 kDa) poly(ethylene oxide) (PEO), for ocular controlled delivery of ofloxacin (OFX) has been extended to investigate the effects of PEO MW, in the 200-2000 kDa range, on insert properties relevant to therapeutic efficacy. Mucoadhesion has shown a dependence on MW, with a maximum for PEO 400. The in vitro drug release from inserts based on PEO 200, PEO 400 and PEO 900 was mainly controlled by insert erosion, whereas with PEO 2000 it was mainly diffusion-controlled in a first phase, followed by an erosion-controlled phase. The erosion time scale depended directly on MW. Immediately after application in the lower conjunctival sac of the rabbit eye, the inserts based on PEO of whichever MW formed mucoadhesive gels, well tolerated by the animals; then the gels spread over the corneal surface and eroded. PEO 2000 was unsuitable as an insert material, since the resulting gel spilled from the eye, due to excessive swelling. The gel residence time in the precorneal area, the drug permanence time in the aqueous humor at concentrations>> MIC and the time to reach the maximal drug concentration in the aqueous humor (C(max)) depended directly on MW, indicating that transcorneal absorption was governed by gel erosion. All inserts increased Cmax and AUCeff (AUC for concentrations>> MIC) with respect to the commercial eyedrops. The increases caused by PEO 400 and PEO 900 were similar (3.78- and 3.16-fold, respectively, for Cmax; 11.06- and 12.37-fold, respectively, for AUCeff), whereas smaller increases were produced by PEO 200. The PEO 400 and PEO 900 inserts have shown a potential for a topical treatment of endophthalmitis.

The interaction of the antibacterial polymer-branched poly(ethylene imine) substituted with quaternary ammonium groups, PEO and alkyl chains, PEI25QI5J5A815-with a solid supported lipid bilayer was investigated using surface sensitive optical waveguide spectroscopy. The analysis of the optogeometrical parameters was extended developing a new composite layer model in which the structural and optical anisotropy of the molecular layers was taken into consideration. Following in situ the change of optical birefringence we were able to determine the composition of the lipid/polymer surface layer as well as the displacement of lipid bilayer by the antibacterial polymer without using additional labeling. Comparative assessment of the data of layer thickness and optical anisotropy helps to reveal the molecular mechanism of antibacterial effect of the polymer investigated.

Urethral catheters, widely used for the drainage of the bladder, are associated with most urinary tract infections (UTIs) that account for 40% of all episodes occurring in acute-care hospitals. This study aimed to develop a gentamicin-releasing catheter that effectively prevents UTIs for short-term catheterization. For physical loading of gentamicin, the urethral catheters were coated by the simple dipping method with poly(ethylene-co-vinyl acetate) (EVA) and EVA/poly(ethylene oxide) (PEO) blends containing gentamicin. By varying the molecular weight (MW) and contents of PEO in the blends, various catheter surfaces were produced. In vitro drug release studies demonstrated that all the coated catheters exhibited sustained release up to 7 days; however, the release pattern was significantly dependant on the coating layers. Of the coated catheters, EVA/PEO (MW = 100k)-coated catheters were utilized to evaluate the antibacterial activity using an inhibition zone test, since they showed a promising drug release behavior and had PEO-rich biocompatible surfaces. In accordance with drug release behavior, EVA/PEO-coated catheters exhibited antibacterial activities for 7 days against Proteus vulgaris, Staphylococcus aureus and Staphylococcus epidermidis. These results imply that the catheters coated with EVA/PEO have a potential for short-term catheterization.

Poly(p-xylylene) (PPX) was deposited by chemical vapor deposition (CVD) on stainless steel substrates. These PPX films were coated by solution casting of poly(lactide)-poly(ethylene oxide)-poly(lactide) triblock copolymers (PLA-PEO-PLA) loaded with 14C-labeled paclitaxel. Adhesion of PLA-PEO-PLA on PPX substrate coatings was measured using the blister test method. Excellent adhesion of the block copolymers on PPX substrates was found. Stress behavior and film integrity of PLA-PEO-PLA was compared to pure PLA on unexpanded and expanded stent bodies and was found to be superior for the block copolymers. The release of paclitaxel from the biodegradable coatings was studied under physiological conditions using the scintillation counter method. Burst release of paclitaxel was observed from PLA-PEO-PLA layers regardless of composition, but an increase in paclitaxel loading was observed with increasing content of PEO.

Widespread emergence of antibiotic-resistant pathogens in recent years has restricted the treatment options for various infectious diseases. Investigation of alternative antimicrobial agents and therapies is thus of utmost importance. Electrospinning of 50 mg/ml 2,3-dihydroxybenzoic acid (DHBA) into 24 % (w/v) poly(D,L-lactide) (PDLLA) and poly(ethylene oxide) (PEO) (1:1) produced nanofibers with an average diameter of 401 ± 122 nm. DHBA released from the nanofibers (315 ± 0.04 µg/ml within 2 h) inhibited the growth of Pseudomonas aeruginosa Xen 5, Klebsiella pneumoniae Xen 39, Escherichia coli Xen 14, Salmonella typhimurium Xen 26, and Staphylococcus aureus strains Xen 30, Xen 31, and Xen 36. The reason for the rapid diffusion of DHBA from PEO:PDLLA may be due to formation of hydrogen bonds between the hydroxyl groups of DHBA and the C=O groups of the PDLLA. DHBA formed a strong interaction with PDLLA and increased the thermal stability of the nanofiber mesh. The DHBA-containing nanofibers were non-hemolytic, suggesting that they may be incorporated in the development of a wound dressing.

Gold nanorods (GNRs) have the potential to be used as imaging and hyperthermia agents for cancer theranostics. Clinical applications of as-synthesized GNRs (i.e., cetyl trimethylammonium bromide (CTAB)-coated GNRs) are currently limited by their cytotoxicity and insufficient colloidal stability. With an aim to address these problems, we developed a self-assembly processing technique for encapsulating GNRs in poly(ethylene oxide)-poly(n-butyl acrylate) (PEO-PnBA) block copolymer (BCP) micelles. This technique uses simple steps of solvent exchange processes, based on the known principles of block copolymer self-assembly. The resultant BCP-encapsulated GNRs were found to be stable against aggregation under physiological salt conditions for indefinite periods of time, which has rarely previously been achieved by other means of encapsulation.

Ultrathin TiO2 films showing rich morphologies are prepared on Si(100) substrates using sol-gel chemistry coupled with an amphilic polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymer as a structure-directing agent. The block copolymer undergoes a good-poor solvent pair induced phase separation in a mixed solution of 1,4-dioxane, concentrated hydrochloric acid (HCl), and titanium tetraisopropoxide (TTIP). By adjusting the weight fractions of 1,4-dioxane, HCl, and TTIP, inorganic block copolymer composite films containing a variety of different morphologies are obtained. On the basis of the results a ternary phase diagram of the morphologies is mapped. By calcination, anatase TiO2 films are achieved. The morphologies and crystallographic phase of the films are studied with AFM, SEM, and XRD, respectively, and the formation mechanisms of the different morphologies are discussed.

Magnetic Block Ionomer Clusters (MBIClusters) with hydrophilic ionic cores and nonionic coronas have been prepared that have ultrahigh transverse NMR relaxivities together with capacities for incorporating high concentrations of polar antibiotic payloads. Magnetite-polymer nanoparticles were assembled by adsorbing the polyacrylate block of an aminofunctional poly(ethylene oxide-b-acrylate) (H2N-PEO-b-PAA) copolymer onto magnetite nanoparticles. The PEO blocks extended into aqueous media to keep the nanoparticles dispersed. Amines at the tips of the H2N-PEO corona were then linked through reaction with a PEO diacrylate oligomer to yield MBIClusters where the metal oxide in the precursor nanoparticles were distinctly separated by the hydrophilic polymer. The intensity average spacing between the magnetite nanoparticles within the clusters was estimated to be ~50 nm. These MBIClusters with hydrophilic intra-cluster space had transverse relaxivities (r2's) that increased from 190 to 604 s-1 mM Fe-1 measured at 1.4 T and 37 °C as their average sizes increased. The clusters were loaded with up to ~38 wt% of the multi-cationic drug gentamicin. MRI scans focused on the livers of mice demonstrated that these MBIClusters are sensitive contrast agents.

The PVC-g-MnG polymers were synthesized by photo-induced graft copolymerization of methoxypoly (ethyleneoxide)monomethacrylate (MnG) with various chain lengths (n) of polyethyleneoxide (PEO) (n = 4, 9, 15, 23, 50, 100) as side chains to polyvinylchloride (PVC) with photo-sensitive dithiocarbamate groups. Antithrombogenicity has been evaluated in vitro and in vivo. The in vitro and in vivo results indicated that the adsorption of blood elements to the PVC-g-MnG significantly decreased with the increasing PEO chain length (n). From these findings it is suggested that the volume restriction effect resulted from the formation of long-chain PEO on the surface and which effectively suppresses the adsorption of blood elements and prevents the denaturation of blood elements.

A more quantitative understanding of peptide loading and release from polyethylene oxide (PEO) brush layers will provide direction for development of new strategies for drug storage and delivery. In this work we recorded selected effects of peptide structure and amphiphilicity on adsorption into PEO brush layers based on covalently stabilized Pluronic(®)F 108. Optical waveguide lightmode spectroscopy and circular dichroism measurements were used to characterize the adsorption of poly-l-glutamic acid, poly-l-lysine, and the cationic amphiphilic peptide WLBU2, to the brush layers. The structure of WLBU2 as well as that of the similarly-sized homopolymers was controlled between disordered and more ordered (helical) forms by varying solution conditions. Adsorption kinetic patterns were interpreted with reference to a simple model for protein adsorption, in order to evaluate rate constants for peptide adsorption and desorption from loosely and tightly bound states. While more ordered peptide structure apparently promoted faster adsorption and elution rates, resistance to elution while in the PEO layer was dependent on peptide amphiphilicity. The results presented here are compelling evidence of the potential to create anti-fouling surface coatings capable of storing and delivering therapeutics.

The presence of lymph node metastases relevantly and significantly impairs disease-specific survival in patients suffering from squamous cell carcinoma of the upper aerodigestive tract. In a VX2 animal tumor model, we present an interstitial translymphatic therapeutic approach using cis-diaminedichloro-platinum(II) (CDDP) conjugated to a poly(ethylene oxide)-block-poly(lysine) (PEO-b-PLys) block copolymer tracking systems for the successful treatment of lymph node metastases. Most effective was the application of a high cargo-load CDDP tracking system (48 wt. % CDDP) curing 90% of the animals and causing only minor local side-effects. Systems containing 1 or 10 wt. % of CDDP were less effective but still cured 50% of the animals. Moreover, the administration of 1 or 10 wt. % of CDDP consistently limited tumor growth to the draining lymph nodes (50%) and prevented systemic distribution of the metastasis even'with 1 wt. % CDDP load. The systems contained 0.25-0.003 mg/kg per body weight CDDP compared to 1 ml/kg per body weight as usually used for intravenous administration. This approach encourages further and more detailed research of a CDDP-based interstitial translymphatic administration of chemotherapy for lymphogenic metastasizing carcinomas in different body regions.

An expanding number of autosomal diseases has been associated with mitochondrial DNA (mtDNA) depletion and multiple deletions. These disorders have been classified as defects of intergenomic communication because mutations of the nuclear DNA are thought to disrupt the normal cross-talk that regulates the integrity and quantity of mtDNA. In 1989, autosomal dominant progressive external ophthalmoplegia with multiple deletions of mitochondrial DNA was the first of these disorders to be identified. Two years later, mtDNA depletion syndrome was initially reported in infants with severe hepatopathy or myopathy. The causes of these diseases are still unclear, but genetic linkage studies have identified three chromosomal loci for AD-PEO. Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE), an autosomal recessive disorder associated with both mtDNA depletion and multiple deletions, is now known to be due to loss-of-function mutations in the gene encoding thymidine phosphorylase. Increased plasma thymidine levels in MNGIE patients suggest that imbalanced nucleoside and nucleotide pools in mitochondria may lead to impaired replication of mtDNA. Future research will certainly lead to the identification of additional genetic causes of intergenomic communication defects and will likely provide insight into the normal "dialogue" between the two genomes.

BACKGROUND

Patients with mitochondrial myopathies may develop cardiac complications such as cardiomyopathy and/or cardiac conduction defects. To identify these potentially life-threatening and treatable conditions, it is common practice to screen patients intermittently with electrocardiography and echocardiography. The optimal time interval for such screening investigations is unknown. We developed this study to review our screening results in adult-onset patients with progressive external ophthalmoplegia (PEO).

METHODS

This study was a retrospective review of PEO patients with 5 years or more of cardiac screening investigations who did not have any cardiac symptoms.

RESULTS

Fifteen patients were included, and cardiomyopathy was identified on screening echocardiogram in 1 patient. Four patients had other abnormalities identified, which were unrelated to their mitochondrial myopathy.

CONCLUSIONS

Only 1 patient in 15 developed cardiac complications related to mitochondrial disease during 5 years of follow-up. We suggest that a screening interval of 3-5 years is probably appropriate for adult-onset PEO patients who do not have cardiac symptoms.

BACKGROUND

Tetracyclines could have neuroprotective effects in neuromuscular and neurodegenerative disorders. AIMS OF THE STUDY AND METHODS: Objective of this double-blind randomized pilot study (followed by an adjunctive open-label phase) was to evaluate whether tetracycline (500 mg/day × 14 days/month × 3 months) could be useful in patients (n = 16) with progressive external ophthalmoplegia (PEO).

RESULTS

Our results do not formally support any effect of tetracycline on eye motility in PEO. However, some possible protective effects could not be completely ruled out, i.e. a further analysis suggests a possible difference between the tetracycline group and the placebo group, significant at least for oblique motility, when comparing the ratio between the end of the double-blind phase and baseline. Tetracycline could modify some oxidative stress biomarkers in patients with PEO.

CONCLUSIONS

Further studies are needed to confirm such effects of tetracycline in patients with PEO, if any, and to clarify the mechanisms of action for antioxidant effects of tetracyclines in mitochondrial disorders and other diseases.

The direct plasma-induced deposition of tri(ethylene glycol) monoallyl ether is reported. RF plasma polymerization of this monomer was carried out under both continuous wave (CW) and pulsed plasma operation. The major focus of this work was optimization of the degree of retention of the C-O-C bonds of the starting monomer during the deposition process. This successfully was accomplished using low RF power during the CW runs and low RF duty cycles during the pulsed plasma experiments. Spectroscopic analysis of the plasma films revealed a strong dependence of film composition on the RF power and duty cycles employed. In particular, an unusually high level of film chemistry compositional control was demonstrated for the pulsed plasma studies, with film composition varying in a steady, progressive fashion with sequential changes in the ratios of plasma on to plasma off times. This film chemistry controllability is demonstrated despite the relatively low volatility of the starting monomer. The utility of this plasma deposition approach in introducing polyethylene oxide (PEO) structures on solid substrates was evaluated via protein adsorption studies. Radiolabeled bovine albumin adsorption was studied on plasma-modified poly(ethylene teraphthalate) (PET) substrates. Dramatic reductions in both initial adsorption and retention of this protein were observed on PET samples having maximal PEO content relative to its adsorption on untreated PET surfaces. Good stability and adhesion of the plasma films to the underlying PET substrates were observed, as evidenced from prolonged immersion of plasma-treated surfaces in aqueous solution. Overall, the results obtained from the present work provide additional support for the utility of one-step plasma process to reduce biological fouling of surfaces via deposition of PEO surface units.

Recombinant adeno-associated virus (rAAV) vectors are well suited carriers to provide durable treatments for human osteoarthritis (OA). Controlled release of rAAV from polymeric micelles was already shown to increase both the stability and bioactivity of the vectors while overcoming barriers, precluding effective gene transfer. In the present study, we examined the convenience of delivering rAAV vectors via poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) polymeric (PEO-PPO-PEO) micelles to transfer and overexpress the transcription factor SOX9 in monolayers of human OA chondrocytes and in experimentally created human osteochondral defects. Human osteoarthritic (OA) chondrocytes and human osteochondral defect models were produced using human OA cartilage obtained from patients subjected to total knee arthroplasty. Samples were genetically modified by adding a rAAV-FLAG-h sox9 vector in its free form or via polymeric micelles for 10 days relative to control conditions (unmodified cells). The effects of sox9 overexpression in human OA cartilage samples were monitored by biochemical, histological, and immunohistochemical analyses. Delivery of rAAV-FLAG-h sox9 via polymeric micelles enhanced the levels of sox9 expression compared with free vector administration, resulting in increased proteoglycan deposition and in a stimulated cell proliferation index in OA chondrocytes. Moreover, higher production of type II collagen and decreased hypertrophic events were noted in osteochondral defect cultures when compared with control conditions. Controlled therapeutic rAAV sox9 gene delivery using PEO-PPO-PEO micelles is a promising, efficient tool to promote the remodelling of human OA cartilage.