Nanoparticle-Reinforced Tough Hydrogel as a Versatile Platform for Pharmaceutical Drug Delivery: Preparation and in Vitro Characterization.

Natural polymer-based hydrogels are excellent for encapsulating hydrophilic drugs, but they are mechanically weak and degrade easily. In this communication, we exploit the electrostatic interaction between nanosilicates (nSi) and gelatin methacrylate (GelMA) to form a mechanically tough nanocomposite hydrogel for pharmaceutical drug delivery. These hydrogels, prepared at subzero temperatures to form cryogels, displayed macroporous structures, which favors cell infiltration. The designed tough cryogel also showed a slower rate of degradation. Furthermore, we encapsulated the small molecule metformin and sustained the drug release under physiological conditions. Cryogel-loaded metformin reduced the effect of endothelial cell injury caused by nutrient deprivation in vitro. Finally, we hypothesize that this versatile nanocomposite material will find use in diverse biomedical applications.

The Clinical Effects of Utilizing Allogeneic Acellular Dermal Matrix in the Surgical Therapy of Anterior Urethral Stricture.

OBJECTIVE: The aim of this study was to estimate the clinical effects of allogeneic acellular dermal matrix (ADM) in the surgical therapy of anterior urethral stricture (AUS). METHODS: We retrospectively collected the clinical data of 49 patients with AUS who underwent urethral repair surgery with ADM in the Department of Urology of the Peking University People's Hospital, and in the First Affiliated Hospital of the People's Liberation Army, from September 2015 to January 2019. The changes in urine flow rate and conditions of urethral mucosal coverage were observed as well as complications and outcomes, and statistical analysis was performed. RESULTS: The average maximum urine flow rates at the 1st, 6th, and 12th month post-surgery were 16.3 ± 1.5, 15.0 ± 1.9, and 14.6 ± 2.1 mL/s, respectively. These values were significantly higher than the preoperative maximum urine flow rate, 1.3 ± 0.5 mL/s (p < 0.05). Cystoscopy was performed in 11 patients 12 months after surgery, with microscopic assessment revealing good urethral epithelial mucosal coverage. Only 2 patients developed infection 2-4 weeks after surgery, while 7 patients developed noninfective urethral restricture 6-10 months after surgery and 1 patient developed urinary fistula 5 months after surgery. All of these statuses improved after receiving appropriate treatment. CONCLUSIONS: Use of ADM represents a new option for the surgical management of AUS repair and reconstruction, with positive clinical effects. In addition, it has the advantages of convenient for operation procedures and access, with no need for additional sampling surgery.

Reversing current rectification to improve DNA-sensing sensitivity in conical nanopores.

Herein, we report the ultrasensitive DNA detection through designing an elegant nanopore biosensor as the first case to realize the reversal of current rectification direction for sensing. Attributed to the unique asymmetric structure, the glass conical nanopore exhibits the sensitive response to the surface charge, which can be facilely monitored by ion current rectification curves. In our design, an enzymatic cleavage reaction was employed to alter the surface charge of the nanopore for DNA sensing. The measured ion current rectification was strongly responsive to DNA concentrations, even reaching to the reversed status from the negative ratio (-6.5) to the positive ratio (+16.1). The detectable concentration for DNA was as low as 0.1 fM. This is an ultrasensitive and label-free DNA sensing approach, based on the rectification direction-reversed amplification in a single glass conical nanopore.

Targeted disruption of the spermatid-specific gene Spata31 causes male infertility.

Spata31, a novel testis-specific gene, was first isolated from the testis of a vitamin A-deficient rat model. To gain insight into its physiological function, Spata31-targeted knockout mice were generated by homologous recombination. Spata31-deficient (Spata31(flox/flox) ; Vasa-Cre) male mice exhibited low sperm count and premature shedding of germ cells into the lumen, ultimately causing azoospermia and male sterility. Mechanistically, the Spata31 deficiency resulted in reduced expression of the adhesion protein nectin-3 and cytoskeletal protein ß-actin at the apical ectoplasmic specialization. Our findings demonstrate that the disruptions to the SPATA31 ortholog could be linked to human male infertility.

The dose-dependence biological effect of laser fluence on rabbit fibroblasts derived from urethral scar.

Two-micrometer laser vaporization resection has been used in clinic for years, but some patients received the treatment are still faced with excessive and abnormal wound repair which leads to the recurrent of urethral stricture eventually. Fibroblasts play a key role in the processes of "narrow-expansion/operation-restenosis" recurring problems. Here, we investigated the effect of laser fluence biomodulation on urethral scar fibroblasts as well as the underlying mechanism. Urethral scar fibroblasts were isolated and cultured, and laser irradiation (2 µm) was applied at different laser fluence or doses (0, 0.125, 0.5, 2, 8, 32 J/cm(2)) with a single exposure in 1 day. The effect of 2-µm laser irradiation on cell proliferation, viability, and expression of scar formation related genes were investigated. Two-micrometer laser irradiation with intermediate dose (8 J/cm(2)) promoted scar fibroblasts proliferation and reactive oxygen species (ROS) production, while higher doses of 32 J/cm(2) are suppressive as it decreased the survival rate, viability, and proliferation of fibroblasts. In addition, qRT-PCR and Western blotting results both proven that collagen type I, collagen IV, MMP9, and CTGF display significant increase, yet the TGF-ß1 expression was severely reduced at intermediate dose (8 J/cm(2)) group when compared with the others groups. Our findings suggest the scar formation-related genes are sensitive to intermediate laser irradiation dose, the most in scar fibroblasts. We revealed the bioeffect and molecular mechanism of 2-µm laser irradiation on rabbit urethral scar fibroblasts. Our study provides new insights into the mechanisms which involved in the excessive and abnormal wound repair of 2-µm laser vaporization resection. These results could potentially contribute to further study on biological effects and application of 2-µm laser irradiation in urethral stricture therapy.

Complex association between ERCC2 gene polymorphisms, gender, smoking and the susceptibility to bladder cancer: a meta-analysis.

Genetic polymorphisms in DNA repair genes may be involved in increasing the risk of bladder cancer. Association studies on the excision repair cross-complementation group 2 (ERCC2) gene polymorphisms and bladder cancer risk have reported conflicting results. The aim of this meta-analysis of eligible cancer case-control studies is to investigate the role of ERCC2 SNPs (Arg156Arg, Asp312Asn, and Lys751Gln), gender and smoking in determining susceptibility to bladder cancer. A literature search was conducted in the PubMed, Embase, Web of Science, Cochrane Library, and Google Scholar databases to indentify eligible studies published before December 1, 2013. We performed a meta-analysis of 23 case-control studies with a total of 7,062 bladder cancer patients and 8,832 controls. The overall analysis suggested that ERCC2 Arg156Arg, Asp312Asn, and Lys751Gln are associated with increased bladder cancer risk. For ERCC2 Arg156Arg, the mutant allele was associated with a 1.36-fold (95 % CI=1.15-1.61) increased risk of bladder cancer. For ERCC2 Asp312Asn, individuals with the Asn allele were associated with a 1.29-fold (95 % CI=1.13-1.48) increased risk of bladder cancer. For ERCC2 Lys751Gln, individuals who carried the variant heterozygote Lys/Gln or homozygote Gln/Gln had a significantly increased bladder cancer risk, compared with the wild genotype Lys/Lys (OR=1.10, 95 % CI=1.03-1.18). Furthermore, gender and smoking may modify the association between these SNPs and bladder cancer risk. This study provides the strongest evidence to date for the role of common variants of the ERCC2 gene in bladder carcinogenesis. Further studies comprehensively characterizing other DNA repair pathways and accounting for exposure to relevant environmental factors should offer further insight into the role of DNA repair in bladder cancer.

Smart Nano-switch with Flexible Modulation of Ion Transport Using Multiple Environmental Stimuli.

In this work, we demonstrate a unique nano-switch with triple environmental stimuli based on the action of functional copolymer brushes in a single conical nanochannel. This nanodevice flexibly and efficiently modulates ion transport properties under the influence of three environmental stimuli: light, pH and temperature. The triple factors can not only play a regulatory role independently, but their synergistic cooperation could fully activate the ionic gate and reversibly control the gating direction. In addition, the nano-switch can switch transport properties on demand in the face of complex combinations of different factors. This work promotes the development of intelligent bionic ion channels, which holds promise for biosensing, energy conversion and biomedical research.

Cocrystals, Salts, and Salt-Solvates of olanzapine; selection of coformers and improved solubility.

Pharmaceutical cocrystals and salts are extensively researched in recent years due to their ability to tune the physicochemical properties of active pharmaceutical ingredients (APIs). A model API, olanzapine, an atypical antipsychotic drug classified as Biopharmaceutical Classification System class II, is used in this study. Cocrystals and salts of olanzapine are discovered using solvent drop grinding and ball milling. Appropriate coformers were selected based on a combination of hydrogen-bond propensity (HBP) and hydrogen-bond coordination (HBC) calculations. Eight new multicomponent phases of olanzapine, including one cocrystal hydrate with phenol; four anhydrous salts with salicylic acid, terephthalic acid, anthranilic acid, 3-hydroxybenzoic acid, and 2-aminoterephthalic acid; one salt dihydrate with terephthalic acid; and one salt solvate with 3-hydroxybenzoic acid and acetonitrile, have been discovered and characterized by PXRD and DSC. One reported cocrystal (olanzapine-resorcinol) has also been considered for the dissolution test. All these newly formed solid phases followed the "ΔpKa rule of 3". The crystal structures of cocrystal/salts were determined by single-crystal X-ray (sc-XRD) diffraction. With the collected single-crystal data, the crystal packings were found to be primarily stabilized via strong hydrogen bonds between carboxyl, phenolic hydroxyl of co-formers/salt-formers with the piperazine and diazepine nitrogen of olanzapine, which confirmed the predicted result from the HBP and HBC calculations. HPLC coupled with UV-vis detector was used in the solubility and dissolution test instead of UV-vis spectroscopy, to avoid the peak overlap between olanzapine and co-formers/salt-formers. A threefold increase in the solubility was observed in olanzapinium 3-hydroxybenzoate and olanzapinium anthranilate, and an almost fivefold increase in solubility of olanzapinium 2-aminoterephthalate.

Smart pH-Modulated Two-Way Photoswitch Based on a Polymer-Modified Single Nanochannel.

In this article, we have demonstrated a smart pH-modulated two-way photoswitch that can reversibly switch ion transport under alternating light exposure over a wide pH range. This photoswitch was prepared by functionalizing the interior of a single conical glass nanochannel with a poly-spiropyran-linked methacrylate (P-SPMA) polymer through surface-initiated atom transfer radical polymerization. The P-SPMA polymer brushes comprise functional groups that are responsive to light and pH, which can cause configuration and charge changes to affect the properties of the nanochannel wall. The SPMA polymer-modified nanochannel not only reversibly controlled ion transport under alternating light irradiation but also efficiently and flexibly regulated the direction and extent of the ion transport based on the pH. This two-way photoswitch exhibits the considerable potential of photoresponsive polymers for the advancement of "intelligent" bionic nanochannel devices for ion screening and optical sensing in various applications.

Human Acellular Dermal Matrix Augmentation Phalloplasty Surgery.

INTRODUCTION AND OBJECTIVE: Many men often have the need to enlarge their penises for psychological gain and to satisfy or to impress their partners. Many surgical techniques have been reported. However, none is the gold standard. AIM: To evaluate the efficacy and safety of human acellular dermal matrix allograft in augmentation phalloplasty technique. METHODS: From March 2015 to September 2017, a total of 182 patients were prospectively recruited into our cohort after complete physical and psychological evaluation that deemed suitable for penile enhancement. Penis circumference was measured at the mid-length of the penis. Mean was 7.03 cm (6.93 ± 1.00 cm) and 12.1 cm (10.59 ± 1.15 cm) during flaccid and erection, respectively. All patients received human acellular dermal matrix graft under spinal or local anesthesia. The allograft was preconditioned in normal saline for 20 minutes, and mesh incisions were made to optimize blood flow. The width was equal to the circumference of both corpus cavernosa but without corpus spongiosum. The length of the graft was determined by measuring the length between the tip of the coronary sulcus and the root of penis. A complete incision below the coronary sulcus to the depth of the Buck's fascia was made. Then separate the dartos fascia from the Buck's fascia. The prepared graft was then placed on top of the Buck's fascia, with the blood-remained side facing the Buck's fascia. The graft was sutured using 4-0 absorbable polyglycolic acid suture to the Buck's fascia. Extra caution needed to be taken when fixing ventrally to avoid injuring the urethra. Once completed, the dartos fascia was restored, the dartos fascia and subcutaneous tissue were sutured with 4-0 absorbable suture, and skin closure is achieved subsequently. RESULTS: The post-operative course was without complications. At the follow-up after 1 year, the mean flaccid girth increased to 8.07 ± 1.06 cm (P < .05), while the mean erect girth increased to 12.79 ± 1.23 cm (P < .05). Sexual activity was allowed after 8 weeks of surgery. The majority reported that sexual self-esteem and functioning significantly improved. In addition, 59 patients reported alleviation of premature ejaculation. CONCLUSIONS: Compared to autologous dermis-fat graft and xenograft, augmentation phalloplasty using human acellular dermal matrix has several advantages: (1) it avoids harm harvesting site of the autograft; (2) the effects of dermis allograft can last at least 1 year; and (3) acellular dermal matrix is more likely to be accepted by people.

INTRODUCTION ET OBJECTIF: De nombreux hommes ressentent le besoin de subir une augmentation du pénis pour des raisons psychologiques et pour impressionner leur conjointe. Il existe de nombreuses techniques chirurgicales, mais aucune n'est la norme de référence. BUT: Évaluer l'efficacité et l'innocuité de l'allogreffe par matrice dermique acellulaire dans la technique de phalloplastie. MÉTHODOLOGIE: De mars 2015 à septembre 2017, 182 patients ont fait l'objet d'un recrutement prospectif après une évaluation physique et psychologique complète jugée convenable pour l'augmentation pénienne. La circonférence du pénis était mesurée à mi-longueur. La moyenne était de 7,03 cm (6,93±1,00 cm) flasque et de 12,1 cm (10,59±1,15 cm) en érection. Tous les patients ont reçu une greffe de matrice dermique acellulaire humaine sous anesthésie spinale ou locale. L'allogreffe était préconditionnée 20 minutes dans une solution physiologique, et des incisions en treillis étaient pratiquées pour optimiser la circulation sanguine. La largeur était égale à la circonférence des deux corps caverneux, mais sans le corps spongieux. La longueur de la greffe était déterminée par la mesure de la longueur entre le bout du sillon coronaire et la racine du pénis. Une incision complète était pratiquée sous le sillon coronaire jusque dans la profondeur du fascia de Buck, puis le fascia du dartos était séparé du fascia de Buck. La face sur laquelle se trouve le sang de la greffe préparée était ensuite placée sur le fascia de Buck. La greffe était cousue au fascia de Buck à l'aide d'une suture d'acide polyglycolique absorbable 4-0. Il fallait faire preuve d'une extrême prudence pour la fixer sur la face ventrale afin d'éviter d'endommager l'urètre. Une fois l'intervention terminée, le fascia du dartos était restauré, le fascia du dartos et les tissus sous-cutanés étaient cousus à l'aide d'une suture absorbable 4-0, puis la peau était refermée. RÉSULTATS: L'évolution postopératoire s'est déroulée sans complications. Au suivi au bout d'un an, la circonférence flasque moyenne était passée à 8,07±1,06 centimètres (P < 0,05), et la circonférence en érection, à 12,79±1,23 centimètres (P < 0,05). L'activité sexuelle était autorisée huit semaines après l'opération. La majorité des patients ont constaté une amélioration importante de l'estime de soi sexuelle et du fonctionnement sexuel. De plus, 59 patients ont déclaré une atténuation de l'éjaculation précoce. CONCLUSIONS: Par rapport à la greffe autologue de derme et de graisse et à la xénogreffe, la phalloplastie d'augmentation par matrice dermique acellulaire humaine comportait plusieurs avantages : 1) elle évite les dommages au foyer de prélèvement de l'autogreffe; 2) les effets de l'allogreffe du derme peuvent durer au moins un an; 3) la matrice dermique acellulaire est plus susceptible d'être acceptée.

Encapsulated three-dimensional bioprinted structure seeded with urothelial cells: a new construction technique for tissue-engineered urinary tract patch.

BACKGROUND: Traditional tissue engineering methods to fabricate urinary tract patch have some drawbacks such as compromised cell viability and uneven cell distribution within scaffold. In this study, we combined three-dimensional (3D) bioprinting and tissue engineering method to form a tissue-engineered urinary tract patch, which could be employed for the application on Beagles urinary tract defect mode to verify its effectiveness on urinary tract reconstruction. METHODS: Human adipose-derived stem cells (hADSCs) were dropped into smooth muscle differentiation medium to generate induced microtissues (ID-MTs), flow cytometry was utilized to detect the positive percentage for CD44, CD105, CD45, and CD34 of hADSCs. Expression of vascular endothelial growth factor A (VEGFA) and tumor necrosis factor-stimulated gene-6 (TSG-6) in hADSCs and MTs were identified by Western blotting. Then the ID-MTs were employed for 3D bioprinting. The bioprinted structure was encapsulated by transplantation into the subcutaneous tissue of nude mice for 1 week. After retrieval of the encapsulated structure, hematoxylin and eosin and Masson's trichrome staining were performed to demonstrate the morphology and reveal collagen and smooth muscle fibers, integral optical density (IOD) and area of interest were calculated for further semi-quantitative analysis. Immunofluorescent double staining of CD31 and α-smooth muscle actin (α-SMA) were used to reveal vascularization of the encapsulated structure. Immunohistochemistry was performed to evaluate the expression of interleukin-2 (IL-2), α-SMA, and smoothelin of the MTs in the implanted structure. Afterward, the encapsulated structure was seeded with human urothelial cells. Immunofluorescent staining of cytokeratins AE1/AE3 was applied to inspect the morphology of seeded encapsulated structure. RESULTS: The semi-quantitative assay showed that the relative protein expression of VEGFA was 0.355 ±â€Š0.038 in the hADSCs vs. 0.649 ±â€Š0.150 in the MTs (t = 3.291, P = 0.030), while TSG-6 expression was 0.492 ±â€Š0.092 in the hADSCs vs. 1.256 ±â€Š0.401 in the MTs (t = 3.216, P = 0.032). The semi-quantitative analysis showed that the mean IOD of IL-2 in the MT group was 7.67 ±â€Š1.26, while 12.6 ±â€Š4.79 in the hADSCs group, but semi-quantitative analysis showed that there was no statistical significance in the difference between the two groups (t = 1.724, P = 0.16). The semi-quantitative analysis showed that IOD was 71.7 ±â€Š14.2 in non-induced MTs (NI-MTs) vs. 35.7 ±â€Š11.4 in ID-MTs for collagen fibers (t = 3.428, P = 0.027) and 12.8 ±â€Š1.9 in NI-MTs vs. 30.6 ±â€Š8.9 in ID-MTs for smooth muscle fibers (t = 3.369, P = 0.028); furthermore, the mean IOD was 0.0613 ±â€Š0.0172 in ID-MTs vs. 0.0017 ±â€Š0.0009 in NI-MTs for α-SMA (t = 5.994, P = 0.027), while 0.0355 ±â€Š0.0128 in ID-MTs vs. 0.0035 ±â€Š0.0022 in NI-MTs for smoothelin (t = 4.268, P = 0.013), which indicate that 3D bioprinted structure containing ID-MTs could mimic the smooth muscle layer of native urinary tract. After encapsulation of the urinary tract patch for additional cell adhesion, urothelial cells were seeded onto the encapsulated structures, and a monolayer urothelial cell was observed. CONCLUSION: Through 3D bioprinting and tissue engineering methods, we provided a promising way to fabricate tissue-engineered urinary tract patch for further investigation.

Evaluating the potential of charred bone as P hotspot assisted by phosphate-solubilizing bacteria.

The enhanced phosphorus (P) release from charred bone by microorganisms results in hotspots to alleviate P limitation in agricultural and natural systems. This study compared P release, assisted by phosphate-solubilizing bacteria (PSB), from charred bone (CB) produced at various temperatures (100-300 °C). In the absence of PSB, soluble P from CB in water was observed with fluctuation between 100 and 300 °C, with a maximum value of 8.66 mg/L at 200 °C. Similarly, kinetics of dissolution indicated that CB produced at 250 °C owned the highest solubility and dissolution rate. After the addition of PSB, soluble P from all the CB samples were all elevated. The CB produced at 100 °C incredibly showed the most significant enhancement (from 3.51 to 77.37 mg /L). ATR-IR and XPS confirmed the loss of organic matter (primarily collagen), but no significant mineralogical alternation of bioapatite in bone. Meanwhile, it demonstrated that collagen itself cannot provide soluble P. However, the collagen contributed to the substantial sorption of bacteria, which improved the efficiency of P release from CB surface. This study clarified the P release via the interaction between CB and PSB, and hence provided a new perspective on understanding P biogeochemical cycle in ecosystem.

Development of a poly-L-lactide salivary duct stent.

Obstructive salivary gland diseases are common conditions that arise following the disruption of the secretary ductal system and usually results in the swelling and pain of the affected gland(s). There has been an increase in the use of sialendoscopy for the treatment and diagnosis of obstructive salivary gland infection. If damage occurs to a duct or papilla following sialendoscopy, a stent may be necessary to prevent restenosis and for maintaining the salivary duct open after complete sialendoscopy. Currently, there are only non-biodegradable salivary duct stents available. The aim of the current study was to establish a methodology for the fabrication of a biodegradable poly-L-lactide (PLLA) salivary duct stent and to examine its function in an animal model. In the current study, PLLA was used to fabricate a salivary duct stent, which was compared with other commercially available non-biodegradable products. The mechanical tests revealed that the tensile strength of the PLLA stent was similar to that of the commercially available non-biodegradable stents. The Young's modulus, which measures the stiffness of a solid material, was significantly higher for the PLLA stent compared with the commercially available non-biodegradable stents. In addition, the current study demonstrated that the PLLA salivary duct stent was easily used with current sialendoscopy techniques, allowing accurate stent placement in an animal model.

Acellular dermal matrix in premature ejaculation: A preliminary study.

BACKGROUND: To investigate the efficacy of acellular dermal matrix in penis augmentation (ADMPA) for premature ejaculation (PE). METHODS: A total of 39 patients treated with ADM in penis augmentation from June 2014 to December 2017 were evaluated. Detailed evaluations on PE were conducted before operation and at the 6-month and 2-year follow-up visits after operation. Self-estimated intravaginal ejaculatory latency time (IELT) and 5-item version of the International Index of Erectile Function (IIEF-5) were used to measure the ejaculation and the erectile function for all subjects. RESULTS: Compared to the baseline data, the IELT and IIEF-5 scores were increased, and PE was relieved at 6 months and 2 years after operation. No major complications occurred in the series. Minor complications were resolved with conservative treatment within 3 weeks. The psychosexual impact of the operation was beneficial in the majority of cases. CONCLUSION: Our survey systematically evaluated the effects of ADMPA for PE. ADMPA might be an optional surgical method in patients with PE, especially for those who seek penile augmentation. However, given the small amount of cases involved in this study, further studies on the effect of ADMPA for PE were still needed.

Remediation of lead-contaminated water by geological fluorapatite and fungus Penicillium oxalicum.

Phosphate-solubilizing fungi (PSF) can secrete large amounts of organic acids. In this study, the application of the fungus Penicillium oxalicum and geological fluorapatite (FAp) to lead immobilization was investigated. The formation and morphology of the lead-related minerals were analyzed by ATR-IR, XRD, Raman, and SEM. The quantity of organic acids secreted by P. oxalicum reached the maximum on the fourth day, which elevated soluble P concentrations from 0.4 to 108 mg/L in water. The secreted oxalic acid dominates the acidity in solution. P. oxalicum can survive in the solution with Pb concentration of ~ 1700 mg/L. In addition, it was shown that ~ 98% lead cations were removed while the fungus was cultured with Pb (~ 1700 mg/L) and FAp. The mechanism is that the released P from FAp (enhanced by organic acids) can react with Pb2+ to form the stable pyromorphite mineral [Pb5(PO4)3F]. The precipitation of lead oxalate also contributes to Pb immobilization. However, lead oxalate is more soluble due to its relatively high solubility. P. oxalicum has a higher rate of organic acid secretion compared with other typical PSF, e.g., Aspergillus niger. This study sheds light on bright future of applying P. oxalicum in Pb remediation.

Corrigendum: Microtissues Enhance Smooth Muscle Differentiation and Cell Viability of hADSCs for Three Dimensional Bioprinting.

[This corrects the article on p. 534 in vol. 8, PMID: 28790931.].

Efficient generation of hepatic cells from mesenchymal stromal cells by an innovative bio-microfluidic cell culture device.

BACKGROUND: Mesenchymal stromal cells (MSCs) are multipotent and have great potential in cell therapy. Previously we reported the differentiation potential of human MSCs into hepatocytes in vitro and that these cells can rescue fulminant hepatic failure. However, the conventional static culture method neither maintains growth factors at an optimal level constantly nor removes cellular waste efficiently. In addition, not only is the duration of differentiating hepatocyte lineage cells from MSCs required to improve, but also the need for a large number of hepatocytes for cell therapy has not to date been addressed fully. The purpose of this study is to design and develop an innovative microfluidic device to overcome these shortcomings. METHODS: We designed and fabricated a microfluidic device and a culture system for hepatic differentiation of MSCs using our protocol reported previously. The microfluidic device contains a large culture chamber with a stable uniform flow to allow homogeneous distribution and expansion as well as efficient induction of hepatic differentiation for MSCs. RESULTS: The device enables real-time observation under light microscopy and exhibits a better differentiation efficiency for MSCs compared with conventional static culture. MSCs grown in the microfluidic device showed a higher level of hepatocyte marker gene expression under hepatic induction. Functional analysis of hepatic differentiation demonstrated significantly higher urea production in the microfluidic device after 21 days of hepatic differentiation. CONCLUSIONS: The microfluidic device allows the generation of a large number of MSCs and induces hepatic differentiation of MSCs efficiently. The device can be adapted for scale-up production of hepatic cells from MSCs for cellular therapy.

Study of clinical practical model of urinary system injury.

BACKGROUND: In order to improve the clinical treatment level of urinary system injury, it is necessary to build up an animal model of urinary system wound, which is not only analogous to real clinical practice, but also simple and practical. METHODS: We have developed the third generation of firearm fragment wound generator based on the first and the second producer. The best explosive charge of the blank cartridge was selected by gradient powder loading experiments. The firearm fragment injuries were made to the bulbous urethra of 10 New Zealand male rabbits. One week preoperatively and 2, 4 and 8 weeks postoperatively, all the animals underwent urethroscopy and urethrography. At 2, 4 and 8 weeks postoperatively, two animals were randomly selected and killed, and the urethra was cut off for pathological examination. RESULTS: The shooting distance of the third generation of firearm fragment wound generator is 2 cm. The best explosive charge of the blank cartridge is 1 g of nitrocotton. All rabbits survived the procedures and stayed alive until they were killed. Injuries were limited to bulbous urethra and distal urethra. Round damaged areas, 1-1.5 cm in length, on the ventral wall were observed. Ureteroscopy results showed that canal diameter gradually shrank by over 50% in 9 rabbits. The rate of success was 90%. Urethrography result noted that a 1-1.3 cm stricture was formed at the bulbous urethra. Histology results of injured stricture urethra showed that fibrous connective tissue hyperplasia and hyaline degeneration caused further stricture in the canal. CONCLUSIONS: The third generation of firearm fragment wound generator imitates the bullet firing process and is more accurate and repeatable. The corresponding rabbit model of traumatic complex urethral stricture simulates the real complex clinical conditions. This animal model provides a standardized platform for clinical researches on treating traumatic injuries to the urinary system.