A chitosan/alginate coated nano-liposome to improve intestinal absorption of curcumin for oral administration.

Attempts to improve low absorption and rapid metabolic conversion of curcumin were made by developing curcumin-loaded bilayer nanoliposomes coated with chitosan and alginate for intestinal-specific drug delivery. A curcumin-loaded nano-liposome was prepared with optimized formulations with phosphatidylcholine, curcumin, chitosan, and alginate. The particle size of the optimized formulation was approximately 400 nm, and the encapsulation efficiency was more than 99%. In the in vitro release study, curcumin release from the curcumin-loaded nanoliposome with double layers of chitosan/alginate (CNL-CH/AL) was suppressed in the simulated gastric fluid (SGF, pH 1.2) and enhanced in the simulated intestinal fluid (SIF, pH 6.8). In the in vivo pharmacokinetic study in rats, the CNL-CH/AL-treated group showed a prolonged absorption pattern of curcumin and the area under the plasma concentration-time curve from 0 to 24 h (AUC0-24) was improved 109-fold compared to the control group treated with a curcumin solution without a nanocarrier.

Aluminum Hydroxide Nano- and Microstructures Fabricated Using Scanning Probe Lithography with KOH Ink.

Using scanning probe lithography (SPL) with KOH ink, this study fabricates aluminum hydroxide (Al(OH)3) nano- and microfeatures on a gold (Au) film that has been deposited on an aluminum (Al) layer. Hydroxyl ions (OH-) from the KOH ink loaded onto the Au film can react with the underlying Al layer to form Al(OH)3 structures due to the decrease in the pH of the reacting solution.1 In this process, Al(OH)3 solidification is governed by the pH of the KOH ink solution, which is affected by its volume. Suitably small volumes (down to hundreds of attoliters) of the KOH ink solution can be applied to the substrate surface using dip-pen nanolithography (DPN) and polymer-pen lithography (PPL). Using DPN and PPL printing with the solid (i.e., gel) and liquid phases of KOH ink, sub-micron- (minimum ≈300 nm) and micron-sized (≥4 µm) Al(OH)3 features can be obtained, respectively. The fabrication of Al(OH)3 structures using the proposed pH-dependent solidification process can be achieved with relatively small volumes in ambient conditions without requiring a previously reported molding process.1,2.

Effects of a graphene oxide-alginate sheet scaffold on rotator cuff tendon healing in a rat model.

BACKGROUND: Natural polymer scaffolds used to promote rotator cuff healing have limitations in terms of their mechanical and biochemical properties. This animal study aimed to investigate the effects of combined graphene oxide (GO) and alginate scaffold and the toxicity of GO on rotator cuff healing in a rat model. METHODS: First, the mechanical properties of a GO/alginate scaffold and a pure alginate scaffold were compared. The in vitro cytotoxicity of and proliferation of human tenocytes with the GO/alginate scaffold were evaluated by CCK-8 assay. For the in vivo experiment, 20 male rats were randomly divided into two groups (n = 10 each), and supraspinatus repair was performed: group 1 underwent supraspinatus repair alone, and group 2 underwent supraspinatus repair with the GO/alginate scaffold. Biomechanical and histological analyses were performed to evaluate the quality of tendon-to-bone healing 8 weeks after rotator cuff repair. RESULTS: The GO/alginate scaffold exhibited an increased maximum load (p = .001) and tensile strength (p = .001). In the cytotoxicity test, the cell survival rate with the GO/alginate scaffold was 102.08%. The proliferation rate of human tenocytes was no significant difference between the GO/alginate and alginate groups for 1, 3, 5, and 7 days. Biomechanically, group 2 exhibited a significantly greater ultimate failure load (p < .001), ultimate stress (p < .001), and stiffness (p < .001) than group 1. The histological analysis revealed that the tendon-to-bone interface in group 2 showed more collagen fibers bridging, tendon-to-bone integration, longitudinally oriented collagen fibers, and fibrocartilage formation than in group 1. CONCLUSION: A small amount of GO added to alginate improved the mechanical properties of the scaffold without evidence of cytotoxicity. At 8 weeks after rotator cuff repair, the GO/alginate scaffold improved tendon-to-bone healing without causing any signs of toxicity in a rat model.

Increased interleukin-6 and TP53 levels in rotator cuff tendon repair patients with hypercholesterolemia.

BACKGROUND: A previous study reported that hyperlipidemia increases the incidence of tears in the rotator cuff tendon and affects healing after repair. The aim of our study was to compare the gene and protein expression of torn rotator cuff tendons in patients both with and without hypercholesterolemia. METHODS: Thirty patients who provided rotator cuff tendon samples were classified into either a non-hypercholesterolemia group (n=19, serum total cholesterol [TC] <200 mg/dL) and hypercholesterolemia group (n=11, serum TC ≥240 mg/dL) based on their concentrations of serum TC. The expression of various genes of interest, including COL1A1, IGF1, IL-6, MMP2, MMP3, MMP9, MMP13, TNMD, and TP53, was analyzed by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). In addition, Western blot analysis was performed on the proteins encoded by interleukin (IL)-6 and TP53 that showed significantly different expression levels in real-time qRT-PCR. RESULTS: Except for IGF1, the gene expression levels of IL-6, MMP2, MMP9, and TP53 were significantly higher in the hypercholesterolemic group than in the non-hypercholesterolemia group. Western blot analysis confirmed significantly higher protein levels of IL-6 and TP53 in the hypercholesterolemic group (p<0.05). CONCLUSIONS: We observed an increase in inflammatory cytokine and matrix metalloproteinase (MMP) levels in hypercholesterolemic patients with rotator cuff tears. Increased levels of IL-6 and TP53 were observed at both the mRNA and protein levels. We suggest that the overexpression of IL-6 and TP53 may be a specific feature in rotator cuff disease patients with hypercholesterolemia.

Comparison of the Characteristics of Rotator Cuff Tissue in a Diabetic Rat Model.

This study evaluated the biomechanical and histologic characteristics of the rotator cuff tendon and muscle tissue with rat models with diabetes mellitus (DM) (group 1) and 30 male rats without DM (group 2). We conducted a time zero study without any additional procedures or external variables at 9 weeks after induction of the diabetic rat model. Thereafter, quantitative evaluation of advanced glycation end products (AGEs) was accomplished via enzyme-linked immunosorbent assay and immunohistochemistry (IHC). Fatty infiltration was investigated with Oil Red O staining, and the peroxisome proliferator activated receptor-gamma (PPAR-gamma) value was studied with IHC. Grossly, the supraspinatus tendons of the group 1 rats were more friable and discolored (yellowish) than those of group 2. In the biomechanical analysis, group 1 rats showed significantly inferior ultimate failure load (P=.001) and ultimate stress (P=.02). Group 1 was significantly inferior to group 2 in terms of total histologic scoring (P<.001). Mean AGE levels were significantly higher in group 1 (P<.001), as determined by IHC. In evaluating fatty infiltration, the degree of Oil Red O staining was significantly higher in group 1 (P<.001), but there was no significant difference in PPAR-gamma value between the 2 groups (P=.14). The intact rotator cuffs of rats with DM were associated with inferior biomechanics in association with AGE accumulation and increased fatty infiltration, as confirmed by histologic examination The hyperglycemic state caused by DM is associated with rotator cuff tendon degeneration. [Orthopedics. 2022;45(3):e154-e161.].

Effect of a Porous Suture Containing Transforming Growth Factor Beta 1 on Healing After Rotator Cuff Repair in a Rat Model.

BACKGROUND: The healing failure rate after rotator cuff repair is considerably high. PURPOSE: To evaluate the effect of a porous suture containing transforming growth factor beta 1 (TGF-ß1) on the sustained release of TGF-ß1 and rotator cuff healing in a rat model. STUDY DESIGN: Controlled laboratory study. METHODS: A porous suture was developed, and its tensile strength was measured. TGF-ß1 was delivered using the porous suture, and a TGF-ß1 release test and human fibroblast proliferation assay were performed. For the animal experiment, 30 rats were randomly allocated into 3 groups (n = 10 each). A bilateral supraspinatus tendon tear was made in all the rats, and repair was performed. Group 1 received repair only; group 2, repair and a single injection of TGF-ß1; and group 3, repair using the porous suture containing TGF-ß1. Eight weeks after repair, biomechanical and histological analyses were performed. RESULTS: The porous suture was successfully developed with mechanical properties compatible with the conventional suture, and the sustained release of TGF-ß1 from the porous suture was confirmed. In addition, the cell proliferation assay confirmed the biological safety of the porous suture. In the animal experiment, group 3 biomechanically exhibited the largest cross-sectional area and the highest ultimate failure load and ultimate stress (all P < .05). Histological examination revealed that group 3 showed significantly better collagen fiber density and tendon-to-bone maturation than did groups 1 and 2 (all P < .05). CONCLUSION: The porous suture containing TGF-ß1 could sustainedly and safely release TGF-ß1, and its use during rotator cuff repair could improve rotator cuff healing, as assessed on the basis of the biomechanical and histological changes in the rat model in this study. Considering the effectiveness, safety, and convenience of the porous suture without extra effort in surgery, the findings of the present study will have a far-reaching effect on the treatment of rotator cuff tears. CLINICAL RELEVANCE: The porous suture containing TGF-ß1 might improve healing after rotator cuff repair.

Electrically Conducting Pullulan-Based Nanobiocomposites Using Carbon Nanotubes and TEMPO Cellulose Nanofibril.

Hybrid nanobiocomposite films are prepared using a solution casting by incorporating TEMPO cellulose nanofibrils (TOCNs) and carbon nanotubes (CNTs) into an aqueous solution of pullulan (PULL). The presence of CNT is confirmed by XRD characterization, and the prepared film shows an increased degree of crystallinity after the addition of TOCNs and CNT. The maximum degree of crystallinity value is obtained for CNT 0.5 % (59.64%). According to the Fourier-transform infrared spectroscopy, the shifts of the characteristic -OH peak of PULL occurred after the addition of TOCNs and aqueous CNT (3306.39 to 3246.90 cm-1), confirming interaction between the TOCNs, CNTs, and PULL matrix. The prepared films show enhanced material properties including higher tensile strength (65.41 MPa at low CNT content (0.5%)), water barrier properties, and reduced moisture susceptibility (5 wt.% CNT shows the lowest value (11.28%)) compared with the neat PULL film. Additionally, the prepared films are almost biodegradable within 64 days and show excellent electrical conductivity (0.001 to 0.015 S/mm for 0.5-5% CNT), which suggests a new approach to transform natural polymers into novel advanced materials for use in the fields of biosensing and electronics.

Is a Local Administration of Parathyroid Hormone Effective to Tendon-to-Bone Healing in a Rat Rotator Cuff Repair Model?

To evaluate the effect of local parathyroid hormone (PTH) administration on rotator cuff tendon-to-bone healing in a rat model compared with systemic PTH injection and untreated controls. PTH-alginate scaffold was prepared and sustained release of PTH was confirmed. Bilateral supraspinatus tendon repairs were performed in 39 rats (group 1, supraspinatus repair only; group 2, supraspinatus repair with systemic PTH injection; group 3, supraspinatus repair with local PTH administration via an absorbable scaffold; n = 13 each). Biomechanical (cross-sectional area, mode of failure, load to failure, and ultimate stress: right side) and histological analyses (hematoxylin and eosin stain, Masson's Trichrome stain Picrosirius red stain, Immunohistochemistry for BMP2, PTH1R, ColI, and ColIII: Left side) were performed to evaluate tendon-to-bone healing quality at 8 weeks after repair, and blood test (osteocalcin and procollagen type I N-terminal pro-peptide [PINP] levels) was performed in all rats. There was no intergroup difference in the healing failure rate (p = 0.910) or failure mode (p = 0.585). Biomechanically, subjects in groups 2 and 3 exhibited significantly larger cross-sectional areas and higher ultimate failure loads and ultimate stress than those in group 1 (all p < 0.05); however, no differences were noted between groups 2 and 3 (all p > 0.05). Histologically, groups 2 and 3 exhibited more organized tendon-to-bone interface structures with higher density, parallel orientation, and collagen fiber continuity than group 1 (all p < 0.05 except collagen fiber continuity in group 1 vs. 2); however, no differences in histological parameters between groups 2 and 3 (all p > 0.05). The protein levels of bone morphogenic protein 2, PTH 1 receptor, and collagen I and III and the serum level of PINP were increased in groups 2 and 3 versus group 1 (all p < 0.05) without showing differences between groups 2 and 3 (all p > 0.05). Local PTH administration using an absorbable scaffold improved the biomechanical and histological outcomes of rotator cuff tendon-to-bone healing comparable with systemic PTH injection at 8 weeks after repair in a rat model. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:82-91, 2020.

Fabrication of diffraction gratings by top-down and bottom-up approaches based on scanning probe lithography.

Generation of diffraction gratings by top-down and bottom-up approaches based on scanning probe lithography is demonstrated. With regard to top-down fabrication, silicon nanostructured diffraction gratings are fabricated through one-dimensional (1D) dip-pen-nanolithography (DPN). Nanodot arrays (two-dimensional simple cubic lattice) of alkanethiol self-assembled monolayers (SAMs) are printed by 1D DPN on an Au-film-coated silicon substrate with lattice distances of 700, 1000, and 1200 nm. Silicon nanocircular pillars of length hundreds of nanometers are generated by sequential Au etching and reactive ion etching (RIE) of the 1D DPN printed sample. The performance of the silicon diffraction gratings as a microspectrometer is demonstrated through red, green, and blue color diffraction with white light incident at 45°. Moreover, arrays of zirconia nanoparticles (NPs) with an average diameter of visible wavelength (φ ≈ 470 nm) on an Au substrate are generated via bottom-up fabrication of the diffraction gratings. Microarrays of hydrophilic alkanethiol SAMs are obtained by polymer pen lithography (PPL). Self-assembly of zirconia NPs occurs after the passivation of hydrophobic alkanethiol SAMs of the PPL-printed sample. Fraunhofer diffraction with a square aperture is observed for the zirconia NP diffraction grating fabricated by the bottom-up approach.

Mechanical Augmentation With Absorbable Alginate Sheet Enhances Healing of the Rotator Cuff.

For anatomical restoration of a repaired rotator cuff, mechanical augmentation of the repaired structure is essential. Using histological and biomechanical evaluation in a rat model, the authors sought to determine the efficacy of an absorbable alginate sheet at the supraspinatus tendon-to-bone repair site for healing of the rotator cuff tear. Forty adult (12 weeks old) male Sprague- Dawley wild-type rats were used in this study. The animals were randomly separated into 2 groups: group 1, conventional supraspinatus repair with acute repair; or group 2, supraspinatus repair with absorbable alginate sheet. Biomechanical and histological analyses were performed at 6 and 12 weeks after index rotator cuff surgery. Compared with group 1, group 2 exhibited a significantly greater mean ultimate failure load (group 1, 23.70±3.87 N; group 2, 61.44±43.67 N; P=.023) and mean ultimate stress (group 1, 2.83±0.50 MPa; group 2, 7.36±2.87 MPa; P=.020). However, 6-week outcomes were not significantly different. On histological scoring, compared with group 1, group 2 exhibited a significantly greater mean 6-week score (group 1, 4.10±1.72 points; group 2, 7.80±1.47 points; P<.001) and mean 12-week score (group 1, 3.50±1.00 points; group 2, 5.25±2.62 points; P=.020). Mechanical augmentation with absorbable alginate may improve tendon healing after surgical repair of the rotator cuff. [Orthopedics. 2019; 42(1):e104-e110.].

Synthesis of Iron Oxide/Gold Composite Nanoparticles Using Polyethyleneimine as a Polymeric Active Stabilizer for Development of a Dual Imaging Probe.

The combination of magnetic and plasmonic properties using iron oxide/gold nanocomposite particles is crucial for the development of multimodal molecular imaging probes. In this study, iron oxide/gold composite nanoparticles (NanoIOGs) were synthesized via the on-site reduction of an Au precursor salt by polyethyleneimine (PEI) molecules attached to iron oxide nanoparticles (IONPs), and they were employed in magnetic resonance and dark-field microscope imaging. PEI is considered as a polymeric active stabilizer (PAS), acting as a reducing agent for the synthesis of Au and a dispersant for nanoparticles. When the IONPs prepared at the PEI concentration of 0.02 wt. % were used for the NanoIOG synthesis, Au nanoseeds were formed around the IONPs. The alloy clusters of IONPs/Au crystals were produced with further reduction depending on PEI concentration. The NanoIOGs exhibited superparamagnetism in a magnetic field and plasmonic response in a dark-field (DF) microscope. The sizes, morphologies, magnetizations, and r2 relaxivities of NanoIOGs were affected significantly by the amount of PEI added during the NanoIOG synthesis. It is suggested that the PAS-mediated synthesis is simple and effective, and can be applied to various nanostructured Au-metal alloys.

Sustained Delivery of Transforming Growth Factor ß1 by Use of Absorbable Alginate Scaffold Enhances Rotator Cuff Healing in a Rabbit Model.

BACKGROUND: The failure rate for healing after rotator cuff repair is relatively high. PURPOSE: To establish a system for sustained release of transforming growth factor ß1 (TGF-ß1) using an alginate scaffold and evaluate the effects of the sustained release of TGF-ß1 on rotator cuff healing in a rabbit model. STUDY DESIGN: Controlled laboratory study. METHODS: Before the in vivo animal study, a standard MTS assay was performed to evaluate cell proliferation and metabolic activity on the alginate scaffold. Additionally, an enzyme-linked immunosorbent assay was performed to confirm the capacity of the sustained release of TGF-ß1-containing alginate scaffold. Once the in vitro studies were completed, bilateral supraspinatus tendon repairs were performed in 48 rabbits that were allocated to 3 groups (n = 16 each) (group 1, supraspinatus repair only; group 2, supraspinatus repair with TGF-ß1 single injection; group 3, supraspinatus repair with TGF-ß1 sustained release via an alginate-based delivery system). Biomechanical and histological analyses were performed to evaluate the quality of tendon-to-bone healing at 12 weeks after rotator cuff repair. RESULTS: The cell proliferation rate of the alginate scaffold was 122.30% compared with the control (fresh medium) group, which confirmed that the alginate sheet had no cytotoxicity and enhanced cell proliferation. Additionally, the level of TGF-ß1 was found to increase with time on the alginate scaffold. Biomechanically, group 3 exhibited a significantly heightened ultimate failure load compared with groups 1 and 2 (group 1, 74.89 ± 29.82 N; group 2, 80.02 ± 34.42 N; group 3, 108.32 ± 32.48 N; P = .011) and more prevalent midsubstance tear compared with group 1 ( P = .028). However, no statistical differences were found in the cross-sectional area of the supraspinatus tendon (group 1, 32.74 ± 9.38; group 2, 33.76 ± 8.89; group 3, 34.80 ± 14.52; P = .882) and ultimate stress (group 1, 2.62 ± 1.13 MPa; group 2, 2.99 ± 1.81 MPa; group 3, 3.62 ± 2.24 MPa; P = .317). Histologically, group 3 exhibited a significantly heightened modified total Bonar score (group 1, 5.00 ± 1.54; group 2, 6.12 ± 1.85; group 3, 7.50 ± 1.31; P = .001). In addition, the tendon-to-bone interface for group 3 demonstrated better collagen orientation, continuity, and organization, and the area of new fibrocartilage formation was more evident in group 3. CONCLUSION: At 12 weeks after rotator cuff repair, the authors found improved biomechanical and histological outcomes for sustained release of TGF-ß1 using alginate scaffold in a rabbit model. CLINICAL RELEVANCE: The alginate-bound growth factor delivery system might improve healing after rotator cuff repair in humans.

Preparation of new natural silk non-woven fabrics by using adhesion characteristics of sericin and their characterization.

Electro-spun regenerated silk webs have been extensively studied for biomedical applications because of the simplicity of their fabrication methods However, the productivity of the electro-spinning process is low for web fabrication and the mechanical properties of the electro-spun silk web are not satisfactory, which restricts its commercialization. In this study, a new silk non-woven fabric was successfully fabricated by wetting and hot press treatments using the excellent binding characteristic of sericin. The effects of the press temperature and residual sericin content on the preparation, structure, and properties of the silk non-woven fabric were examined. A press temperature of 200°C was optimum for obtaining non-woven fabrics with best mechanical properties, without yellowing. The silk non-woven fabric could not be fabricated without sericin, and a minimum of 8% sericin was required to fabricate it. As the sericin content was increased, the strength and Young's modulus of the silk non-woven fabric increased, while the tensile elongation remained constant. Regardless of the press temperature and sericin content, all the silk non-woven fabrics showed good cell viability, comparable to that of the tissue culture plate (TCP) used as a control until 4days, which however decreased compared to that of TCP after 7days.

Antioxidative and antiinflammatory activities of quercetin-loaded silica nanoparticles.

Utilizing the biological activities of compounds by encapsulating natural components in stable nanoparticles is an important strategy for a variety of biomedical and healthcare applications. In this study, quercetin-loaded silica nanoparticles were synthesized using an oil-in-water microemulsion method, which is a suitable system for producing functional nanoparticles of controlled size and shape. The resulting quercetin-loaded silica nanoparticles were spherical, highly monodispersed, and stable in an aqueous system. Superoxide radical scavenging effects were found for the quercetin-loaded silica nanoparticles as well as free quercetin. The quercetin-loaded silica nanoparticles showed cell viability comparable to that of the controls. The amounts of proinflammatory cytokines produced by macrophages, such as interleukin 1 beta, interleukin 6, and tumor necrosis factor alpha, were reduced significantly for the quercetin-loaded silica nanoparticles. These results suggest that the antioxidative and antiinflammatory activities of quercetin are maintained after encapsulation in silica. Silica nanoparticles can be used for the effective and stable incorporation of biologically active natural components into composite biomaterials.

Polyethyleneimine-mediated synthesis of superparamagnetic iron oxide nanoparticles with enhanced sensitivity in T2 magnetic resonance imaging.

The development of iron oxide nanoparticles (IONPs) with enhanced r2 relaxivity is important for achieving greater sensitivity in in vivo magnetic resonance (MR) imaging. In this study, it was considered that polyethyleneimine (PEI) could play a role in varying the particle and cluster sizes in IONP synthesis, leading to different r2 relaxivities. To demonstrate this, superparamagnetic IONPs were synthesised in the presence of NH4OH and PEI using a co-precipitation method. PEI acted as an active stabiliser during IONP synthesis, and therefore the particle size, hydrodynamic cluster size, coating layer thickness, saturation magnetisation, and r2 relaxivity were all strongly influenced by the PEI concentration. Monodispersed IONPs with a mean hydrodynamic cluster size of 14.4nm were synthesised at a PEI concentration of 0.05wt% and in this case, the r2 relaxivity was increased up to 227.6mM(-1)s(-1). This confirmed the viability of PEI-mediated synthesis as a means of controlling the particle/cluster size and enhancing the r2 relaxivity. The PEI-IONPs exhibited no significant cytotoxicity up to 132ppm. Rapid and strong uptake of PEI-IONPs was detected in rat liver by in vivo MR imaging. The superparamagnetic PEI-IONPs prepared in this study are considered to be sufficiently sensitive for use as MR imaging contrast agents, which can be used as parent particles for further functional modification.

Alginate-based composite sponge containing silver nanoparticles synthesized in situ.

Silver-based biomaterials have been developed in a variety of bactericidal applications, especially for wound dressings. In this study, silver nanoparticles (AgNPs) were synthesized in a sodium alginate solution and then the composite sponge containing AgNPs was prepared from the nanocolloid solution. The alginate-stabilized AgNPs had the mean negative zeta potential of -52.5mV, suggesting that the surface charge prevents the nanoparticles from aggregating through electrostatic repulsion. The alginate-AgNPs composite sponge had a highly enhanced antimicrobial activity compared to the alginate sponge. In spite of excellent cytocompatibility of the alginate sponge, the viability of the cell treated with the alginate-AgNPs composite sponge extract decreased to 86% of the control. The amount of proinflammatory cytokines released from macrophages treated with the alginate-AgNPs composite sponge was reduced. For the preparation of AgNPs-embedded composites, alginate can be a potential candidate stabilizing AgNPs and providing synergistic antimicrobial and antiinflammatory activities with AgNPs.

Biologic filler using human fibroblasts and placenta extracts.

Soft tissue augmentation with injectable materials has been a challenging problem for plastic and reconstructive surgeons. Although filler materials have been used for soft tissue augmentation, adverse effects such as inflammation, distortion, and repeated procedures due to absorption still exist. In this study, biologic filler containing human fibroblasts and placenta extracts was developed to overcome these problems as a concept of cell therapy.In an in vivo assay, 40 nude mice were divided into 4 groups: 1 control group and 3 experimental groups. Biologic fillers containing human fibroblasts untreated (control), cultured with 0.1% placenta extract (group 1), cultured with 10% fetal bovine serum (group 2), and cultured with both 0.1% placenta extract and 10% fetal bovine serum (group 3) were used in each groups. Cultured human fibroblasts were injected into the back of each mouse with fibrin glue to maintain the shape and volume. These groups were compared during an 8-week period. The gross, histologic, and biomolecular studies were proceeded to evaluate the effect of biologic filler.In geometric maintenance, volumes in experimental groups were 1.6 (group 1), 1.2 (group 2), and 1.9 times (group 3) more reserved than that in the untreated control group (control) at 8 weeks. In histology, abundant proliferation of fibroblasts as well as extracellular matrices including collagen and glycosaminoglycan was visualized in experimental groups. Enzyme-linked immunosorbent assay was used to analyze collagen and glycosaminoglycan, and reverse transcription-polymerase chain reaction was used to analyze the messenger RNA expression of COL1A1, a gene for collagen type 1, which shows a significant difference between control and experimental groups. There is no statistically significant difference between groups 1 and 2; on the other hand, group 3 statistically has the best outcome among the experimental groups.

Antimicrobial polyethyleneimine-silver nanoparticles in a stable colloidal dispersion.

Excellent colloidal stability and antimicrobial activity are important parameters for silver nanoparticles (AgNPs) in a range of biomedical applications. In this study, polyethyleneimine (PEI)-capped silver nanoparticles (PEI-AgNPs) were synthesized in the presence of sodium borohydride (NaBH(4)) and PEI at room temperature. The PEI-AgNPs had a positive zeta potential of approximately +49 mV, and formed a stable nanocolloid against agglomeration due to electrostatic repulsion. The particle size and hydrodynamic cluster size showed significant correlations with the amount of PEI and NaBH(4). PEI-AgNPs and even PEI showed excellent antimicrobial activity against Staphylococus aureus and Klebsiella pneumoniae. The cytotoxic effects of PEI and PEI-AgNPs were confirmed by an evaluation of the cell viability. The results suggest that the amount of PEI should be minimized to the level that maintains the stability of PEI-AgNPs in a colloidal dispersion.

Different effects of PLGA and chitosan scaffolds on human cartilage tissue engineering.

Clinical application of the cartilage formed by tissue engineering is not practical due to the failure to maintain long-term tissue structural integrity. One of the important factors for maintaining integrity is the biomaterial for a scaffold. The purpose of the current study was to evaluate the difference between poly-lactic glycolic acid (PLGA) and chitosan as scaffolds. Human auricular chondrocytes were used. Chondrocyte-scaffold complexes were implanted in nude mice and analyzed at 4, 8, 12, 16, and 24 weeks after implantation. The volume of chondrocyte-PLGA complexes decreased rapidly. The volume of chondrocyte-chitosan complexes was well maintained with a slow decrease rate. In histological findings, mature cartilage was formed by 4 weeks in the PLGA group. However, cartilage structure was hardly found after 16 weeks. In the chitosan group, mature cartilage was detected at 8 weeks and cartilage formation became more marked with time. The expression of type II collagen protein and mRNA became weaker with time in the PLGA group. However, the expression in the chitosan group was strong for the whole period. These results suggest that chitosan is a superior scaffold for cartilage tissue engineering in terms of the maintenance of structural integrity. It is expected that after some modification for more rapid chondrogenesis, chitosan scaffolds may become one of the most useful scaffolds for cartilage tissue engineering.

Tissue-engineered bone formation with gene transfer and mesenchymal stem cells in a minimally invasive technique.

BACKGROUND: The objective of this study was to use a chitosan-alginate gel to implant bone marrow-derived mesenchymal stem cells subcutaneously in a minimally invasive manner and promote bone formation by the simultaneously transferred osteogenic protein (OP)-1 (bone morphogenic protein-7) gene. METHOD AND RESULTS: The complex of polyethylenimine/luciferase plasmid DNA embedded in the gel was able to transfect HEK 293 cells on a culture dish or co-encapsulated in the gel. When injected into the subcutaneous space of mice, luciferase expression was two to three orders of magnitude increased above the background. To examine the efficacy of gene-, cell-, and combined gene- and cell-encapsulated gels in tissue generation, samples were injected into the subcutaneous space of 6-week-old athymic nude mice, and the OP-1 plasmid was studied. At 8 weeks after the injection, the gels only maintained their volumetric shape when human mesenchymal stem cells (hMSCs) were encapsulated, but otherwise the gels were partially dissolved. Transgene expression of OP-1 was clearly detected in the samples after 4 weeks but not after 8 weeks. Type II collagen was detected in all the gels containing the OP-1 plasmid, with or without hMSCs. The samples with the combination of OP-1 DNA and hMSCs revealed strong type II collagen expression as well as osteoid foci. CONCLUSION: These results suggest that combined gene and hMSC delivery within a chitosan-alginate gel could be an interesting approach for tissue engineering.