Biomimetic approach for liquid encapsulation with nanofibrillar cloaks

Technologies that are able to handle microvolumes of liquids, such as microfluidics and liquid marbles, are attractive for applications that include miniaturized biological and chemical reactors, sensors, microactuators, and drug delivery systems. Inspired from natural fibrous envelopes, here, we present an innovative approach for liquid encapsulation and manipulation using electrospun nanofibers. We demonstrated the realization of non-wetting soft solids consisting of a liquid core wrapped in a hydrophobic fibrillar cloak of a fluoroacrylic copolymer and cellulose acetate. By properly controlling the wetting and mechanical properties of the fibers, we created final architectures with tunable mechanical robustness that were stable on a wide range of substrates (from paper to glass) and floated on liquid surfaces. Remarkably, the realized fiber-coated drops endured vortex mixing in a continuous oil phase at high stirring speed without bursting or water losses, favoring mixing processes inside the entrapped liquid volume. Moreover, the produced cloak can be easily functionalized by incorporating functional particles, active molecules, or drugs inside the nanofibers.

A bioartificial renal tubule device embedding human renal stem/progenitor cells

We present a bio-inspired renal microdevice that resembles the in vivo structure of a kidney proximal tubule. For the first time, a population of tubular adult renal stem/progenitor cells (ARPCs) was embedded into a microsystem to create a bioengineered renal tubule. These cells have both multipotent differentiation abilities and an extraordinary capacity for injured renal cell regeneration. Therefore, ARPCs may be considered a promising tool for promoting regenerative processes in the kidney to treat acute and chronic renal injury. Here ARPCs were grown to confluence and exposed to a laminar fluid shear stress into the chip, in order to induce a functional cell polarization. Exposing ARPCs to fluid shear stress in the chip led the aquaporin-2 transporter to localize at their apical region and the Na⁺K⁺ATPase pump at their basolateral portion, in contrast to statically cultured ARPCs. A recovery of urea and creatinine of (20±5)% and (13±5)%, respectively, was obtained by the device. The microengineered biochip here-proposed might be an innovative “lab-on-a-chip” platform to investigate in vitro ARPCs behaviour or to test drugs for therapeutic and toxicological responses.

Polymeric foams with functional nanocomposite cells

Elastomeric foams with controlled cell size and composition are formed by using calcium alginate hydrogel beads as templates.

Combined kidney and vascularized total bladder transplantation: experience in an animal model

BACKGROUND

Few reports have described a partial bladder graft with an en bloc kidney transplantation, mainly to facilitate reconstruction of the urinary tract, but also to augment the native bladder. The present study assessed the feasibility to graft vascularized total bladder in association with a renal transplantation.

METHODS

The right kidney, in continuity with the ureter and the entire bladder, was retrieved from three female pigs weighing 20 g. The visceral bloc was transplanted to three recipient pigs of the same weight. The entire bladder was transplanted with its vascular connection to ensure a better blood supply. After 3 days of observation, one recipient was humanely killed to examine the bladder graft. Oxygen saturation in the bladder graft monitored for 8 hours was compared with the native bladder in the other two recipients. All three bladder grafts were examined by a pathologist.

RESULTS

All bladder grafts seemed to be macroscopically well-perfused upon removal of the vascular clamps. In case 1, the recipient was clinically well with good urinary output over the first 2 days of observation; is contrast, on day 3 the animal displayed an acute reduced urinary output. Laparotomy on day 3 of observation showed recent thrombosis of the bladder and renal graft vessels. In cases 2 and 3, oxygen saturations of the bladder graft were normal during the 8-hour observation period, without any difference between the graft and the native bladder.

CONCLUSIONS

According to our results, vascularized total bladder transplantation is feasible. In combination with renal transplantation, it could be applied as an alternative to bladder augmentation or total bladder replacement.

Strelitzia reginae leaf as a natural template for anisotropic wetting and superhydrophobicity

Artificial surfaces that exhibit unidirectional water spreading and superhydrophobicity are obtained by Strelitzia reginae leaves. Both green and dried leaves are used, thus exploiting the plant senescence. We demonstrate that the natural drying process of the leaves strongly affects the surface morphology and wettability. Polymeric stamps from the green leaf show an arrangement of periodic microridges/microgrooves that favor anisotropic wetting, with a water contact angle (WCA) variation of about 21% along the two principal directions. Instead, the shrinkage of the leaf tissue, as a consequence of the natural dehydration process, induces an enhancement of the superficial corrugation. This results in the establishment of a superhydrophobic state, which shows a WCA of up to 160°, and water rolling off. S. reginae leaves are therefore easily accessible stamps suitable for controlling wettability and realizing surfaces that exhibit various wetting behaviors.

Biophysical properties of normal and diseased renal glomeruli

The mechanical properties of tissues and cells including renal glomeruli are important determinants of their differentiated state, function, and responses to injury but are not well characterized or understood. Understanding glomerular mechanics is important for understanding renal diseases attributable to abnormal expression or assembly of structural proteins and abnormal hemodynamics. We use atomic force microscopy (AFM) and a new technique, capillary micromechanics, to measure the elastic properties of rat glomeruli. The Young's modulus of glomeruli was 2,500 Pa, and it was reduced to 1,100 Pa by cytochalasin and latunculin, and to 1,400 Pa by blebbistatin. Cytochalasin or latrunculin reduced the F/G actin ratios of glomeruli but did not disrupt their architecture. To assess glomerular biomechanics in disease, we measured the Young's moduli of glomeruli from two mouse models of primary glomerular disease, Col4a3(-/-) mice (Alport model) and Tg26(HIV/nl) mice (HIV-associated nephropathy model), at stages where glomerular injury was minimal by histopathology. Col4a3(-/-) mice express abnormal glomerular basement membrane proteins, and Tg26(HIV/nl) mouse podocytes have multiple abnormalities in morphology, adhesion, and cytoskeletal structure. In both models, the Young's modulus of the glomeruli was reduced by 30%. We find that glomeruli have specific and quantifiable biomechanical properties that are dependent on the state of the actin cytoskeleton and nonmuscle myosins. These properties may be altered early in disease and represent an important early component of disease. This increased deformability of glomeruli could directly contribute to disease by permitting increased distension with hemodynamic force or represent a mechanically inhospitable environment for glomerular cells.

Reduction of water evaporation in polymerase chain reaction microfluidic devices based on oscillating-flow

Producing polymeric or hybrid microfluidic devices operating at high temperatures with reduced or no water evaporation is a challenge for many on-chip applications including polymerase chain reaction (PCR). We study sample evaporation in polymeric and hybrid devices, realized by glass microchannels for avoiding water diffusion toward the elastomer used for chip fabrication. The method dramatically reduces water evaporation in PCR devices that are found to exhibit optimal stability and effective operation under oscillating-flow. This approach maintains the flexibility, ease of fabrication, and low cost of disposable chips, and can be extended to other high-temperature microfluidic biochemical reactors.

Enhancement of light polarization from electrospun polymer fibers by room temperature nanoimprint lithography

We demonstrate the enhancement of the polarization ratio of light emitted from electrospun conjugated polymer nanofibers, by means of nanoimprint lithography carried out at room temperature. We provide evidence of tailoring the polarization properties by patterning light-emitting fibers at the nanoscale. The polarization ratios are increased up to a factor of 2.4 by gratings with periodicity (560 nm) matching the emission wavelength of the employed conjugated polymer. The use of room temperature nanoimprint lithography to pattern light-emitting polymer nanofibers represents a strategic route for realizing photonic crystals and distributed feedback polarized emitters on one-dimensional organic nanostructures.

Nanoparticle image velocimetry at topologically structured surfaces

Nanoparticle image velocimetry (nano-PIV), based on total internal reflection fluorescent microscopy, is very useful to investigate fluid flows within approximately 100 nm from a surface; but so far it has only been applied to flow over smooth surfaces. Here we show that it can also be applied to flow over a topologically structured surface, provided that the surface structures can be carefully configured not to disrupt the evanescent-wave illumination. We apply nano-PIV to quantify the flow velocity distribution over a polydimethylsiloxane surface, with a periodic gratinglike structure (with 215 nm height and 2 mum period) fabricated using our customized multilevel lithography method. The measured tracer displacement data are in good agreement with the computed theoretical values. These results demonstrate new possibilities to study the interactions between fluid flow and topologically structured surfaces.

Paclitaxel, ifosfamide, and cisplatin regimen as neoadjuvant chemotherapy in young women with locally advanced squamous cervical cancer

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Background: Chemoradiotherapy is the standard treatment of advanced cervical cancer. Neoadjuvant chemotherapy (NAC) may represent an alternative for locally advanced cervical cancer (LACC).This study was undertaken to evaluate the efficacy of NAC in young patients with squamous LACC. Methods: Since 2000 to 2008, 61 pts (mean age 43 yrs) with squamous LACC were treated with NAC and afterwards evaluated for radical surgery. Eligibility included proven histologically diagnosis of squamous cervical carcinoma, FIGO stage IB2/IIA>4cm/IIB, measurable disease, ECOG PS 0–2, no prior therapy and age under 49 years. All patients received TIP regimen (cisplatin 50 mg/m2 i.v. day 1, paclitaxel 175 mg/m2 over 3 hrs i.v.day1, ifosfamide 5,000 mg/m2 plus mesna 6,000 mg/m2 over 24 hrs i.v. day 1–2). Each cycle was repeated every 21 days. Patients were evaluated 4–6 weeks after the completion of the third cycle with the purpose to perform radical surgery according to clinical response. Results: 35pts (57.4%) were stage IB2; 9 (14.7%) were IIA >4cm; and 17 (27.9%) were IIB. After restaging the clinical results were: CR = 4/61 (6.6%), PR = 51/61 (83.6%); no response = 5/61 (8.2%); progression = 1/61 (1.6%). A total of 55 pts (90.1%) were eligible for surgery; 6/61 pts (9.8%) were submitted to curative radiotherapy (until 2004) or chemoradiotherapy. Pathological responses after surgery were: 4 pCR (7.3%); 46 pPR (83.6%); and 5 (9.1%) pPR with presence of positive surgical margins or metastatic lymph nodes. Out of 55 pts, 50 received 2 cycles of TIP regimen as a consolidation therapy before follow-up; 5 pts with incomplete pPR underwent radio/chemoradiotherapy. After NAC an overall downstaging of LACC was obtained in 50/61 pts (82.0%). In this group of pts at the median follow-up of 42 months (range 4–98) updated as of December 2008, the 3-years progression-free survival and overall survival are 85.9% and 82.0%, respectively. Conclusions: Our results indicate that TIP regimen-based NAC is an attractive option in young women with squamous LACC (IB2,IIA >4cm, IIB) that strongly desire surgery.The rate of patients with a prolonged remission of disease (82.0%) suggests that the clinical benefit of TIP regimen-based NAC followed by surgery may be comparable to chemoradiotherapy.

No significant financial relationships to disclose.

Patterning of light-emitting conjugated polymer nanofibres

Organic materials have revolutionized optoelectronics by their processability, flexibility and low cost, with application to light-emitting devices for full-colour screens, solar cells and lasers. Some low-dimensional organic semiconductor structures exhibit properties resembling those of inorganics, such as polarized emission and enhanced electroluminescence. One-dimensional metallic, III-V and II-VI nanostructures have also been the subject of intense investigation as building blocks for nanoelectronics and photonics. Given that one-dimensional polymer nanostructures, such as polymer nanofibres, are compatible with sub-micrometre patterning capability and electromagnetic confinement within subwavelength volumes, they can offer the benefits of organic light sources to nanoscale optics. Here we report on the optical properties of fully conjugated, electrospun polymer nanofibres. We assess their waveguiding performance and emission tuneability in the whole visible range. We demonstrate the enhancement of the fibre forward emission through imprinting periodic nanostructures using room-temperature nanoimprint lithography, and investigate the angular dispersion of differently polarized emitted light.

Patterning photo-curable light-emitting organic composites by vertical and horizontal capillarity: a general route to photonic nanostructures

We demonstrate the patterning of organic light-emitting composites made by conjugated polymers and photo-curable matrices. Using blends that exhibit both the structural properties of a low-viscosity photo-curable polymer, and the emission features of conjugated light-emitting materials, we study the operational principle of the pattern transfer and the modifications induced by the imprinting and microfluidic procedures on the optical properties of the compounds investigated. The combination of high-resolution silicone and perfluoropolyether elastomeric templates and low-viscosity, light-emitting polymeric blends offers the possibility to easily produce active organic structures with 100 nm scale resolution, thus extending current nanopatterning routes to this important class of composite material.

Ultraviolet-based bonding for perfluoropolyether low aspect-ratio microchannels and hybrid devices

Producing solvent-resistant microfluidic devices is a challenge for analytical chemistry and biochemistry. We demonstrate a simple and low-cost fabrication approach for the realization of solvent-resistant microchannels based on perfluoropolyether elastomers, exhibiting very low aspect ratios (0.01). The strength of the microchannels sealing is evaluated through the maximum internal pressure (1.52 MPa) prior to device failure, due to delamination at the bonded interface. This approach allows the elastic properties of silicone elastomers, suitable for high quality external connections, to be combined with the non-swelling character of perfluoropolyethers.

Weekly topotecan as a salvage therapy in heavily pre-treated patients with recurrent platinum-resistant epithelial ovarian cancer

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Background: The prognosis of patients with recurrent epithelial ovarian cancer is extremely poor after several lines of chemotherapy; this situation becomes more and more difficult to manage in the presence of a platinum-resistance condition. Topotecan 1.5mg/m2 on days 1 through 5 of a 21-day cycle is often employed as a second-line chemotherapy also for platinum-resistant epithelial ovarian cancer. In this phase II study we investigated the safety as well response rate of weekly topotecan as a salvage therapy in heavily pretreated patients with recurrent platinum-resistant epithelial ovarian cancer (RprEOC). Methods: To be elegible for the study patients had to be considered resistant to platinum and paclitaxel pretreated. Eleven patients (median age 51 yrs, range 45 - 70) with performance status 0–2 affected by RprEOC with measurable disease, were planned to receive weekly topotecan. They had received at least 3 prior lines of chemotherapy. Topotecan was administered at the dose of 2.0 mg/m2 via a 30-minute i.v. infusion once every week until disease progression or unacceptable toxicity. Results: All patients were evaluable for toxicity and clinical response. All the 11 pts enrolled had stage III-IV disease. Median number of chemotherapy cycles was 5 (range 3 - 8). A total of 62 cycles were administered. Dose reduction was necessary for 12% of the cycles. Main toxicities included anemia (12%), leucopenia (18%), thrombocytopenia (15%) and asthenia (20%). No deaths were attributable to therapy. No one showed complete response, while two partial response (18.2%) and four stable disease (36.4%) were observed. Five pts (45.4%) progressed on therapy. The median progression-free interval was 13 weeks. Conclusion: Salvage therapy for patients with ovarian cancer who failed several platinum and paclitaxel treatments remains a therapeutic challenge. Topotecan administered at low weekly dosage (2.0 mg/m2) is an active option in the subset of heavily RprEOC and it seems also to be a more tolerable regimen compared to the classical 5-day schedule.

No significant financial relationships to disclose.

Low-loss and highly polarized emission from planar polymer waveguides

The waveguiding properties and amplified spontaneous emission (ASE) of a blend of light-emitting gain-conjugated polymers were investigated. ASE-induced line narrowing occurs for excitation fluences larger than 100 microJ cm(-2), with a maximum optical-gain coefficient of 8 cm(-1). Energy transfer between the host and guest polymers, significantly reducing the self-absorption, leads to a loss coefficient of the waveguide as low as 0.3 cm(-1), which is believed to be the lowest value reported for active organic gain slabs and a highly polarized emission, with a polarization contrast up to 0.65. These results indicate that gain-conjugated polymer blends are state-of-the-art organic materials for lasing devices.