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Castel Guelfo di Bologna, Italy

Chelli B.,CNR Institute of Nanostructured Materials | Chelli B.,Nano4bio S.r.l | Barbalinardo M.,CNR Institute of Nanostructured Materials | Barbalinardo M.,Nano4bio S.r.l | And 7 more authors.
Interface Focus | Year: 2014

Anisotropic orientation and accurate positioning of neural cells is achieved by patterning stripes of the extracellular matrix protein laminin on the surface of polystyrene tissue culture dishes by micromoulding in capillaries (MIMICs). Laminin concentration decreases from the entrance of the channels in contact with the reservoir towards the end. Immunofluorescence analysis of laminin shows a decreasing gradient of concentration along the longitudinal direction of the stripes. The explanation is the superposition of diffusion and convection of the solute, the former dominating at length scales near the entrance (characteristic length around 50 μm), the latter further away (length scale in excess of 900 μm). These length scales are independent of the channel width explored from about 15 to 45 μm. Neural cells are randomly seeded and selectively adhere to the pattern, leaving the unpatterned areas depleted even upon 6 days of incubation. Cell alignmentwas assessed by the orientation of the long axis of the 4′,6-diamidino-2-phenylindole-stained nuclei. Samples on patterned the laminin area exhibit a large orientational order parameter. As control, cells on the unpatterned laminin film exhibit no preferential orientation. This implies that the anisotropy of laminin stripes is an effective chemical stimulus for cell recruiting and alignment. © 2013 The Author(s) Published by the Royal Society. All rights reserved.

Lopomo N.,Laboratorio Of Biomeccanica E Innovazione Tecnologica | Lopomo N.,Laboratorio Of Nanobiotecnologie Nabi | Signorelli C.,Laboratorio Of Biomeccanica E Innovazione Tecnologica | Signorelli C.,Polytechnic of Milan | And 6 more authors.
International Orthopaedics | Year: 2014

Purpose: Despite the overall success of the surgical anterior cruciate ligament (ACL) reconstruction, some patients still present with instability symptoms even after the surgery, mainly due to the presence of associated lesions. At present, the pivot shift test has been reported to be the benchmark to assess rotatory knee laxity. The purpose of this study was to quantitatively evaluate rotatory knee laxity at time-zero in order to determine whether detected post-reconstruction laxity was predictable by its value measured before the reconstruction, which was hypothized to be influenced by the presence of associated lesions. Methods: Rotatory knee laxity was retrospectively analysed in 42 patients, including two different ACL reconstructions. The maximal anterior displacement and the absolute value of the posterior acceleration reached during the reduction of the tibial lateral compartment were intra-operatively acquired by using a navigation system and identified as discriminating parameters. For each parameter, statistical linear regression analysis (line slope and intercept)was performed between preand post-reconstruction values. Results: No statistically significant influence of the initial posterior acceleration on the post-reconstruction outcome was found (line slope, p>0.05), although a statistically significant line intercept was indeed identified (p<0.001). A statistically significant influence on the surgery outcome was instead found for the initial value of the anterior tibial displacement (line slope=0.39, p =0.004), meaning that, on average, about 40% of the post-reconstruction lateral compartment displacement could be explained by the corresponding pre-reconstruction value. Both of these findings highlighted the importance of intra-operative quantification of rotatory knee laxity to identify correct indications for the surgery. Conclusions: This study provided important implications for the future possibility of defining a quantifying tool able to assess rotatory knee laxity during ACL reconstruction. This could allow detection of additional injuries to secondary restraints by easily performing rotatory knee laxity tests, which in turn could reduce post-surgical recurrence of knee instability. © Springer-Verlag 2014.

Lopomo N.,Laboratorio Of Biomeccanica E Innovazione Tecnologica | Lopomo N.,Laboratorio Of Nanobiotecnologie Nabi | Signorelli C.,Laboratorio Of Biomeccanica E Innovazione Tecnologica | Signorelli C.,Polytechnic of Milan | And 4 more authors.
Knee Surgery, Sports Traumatology, Arthroscopy | Year: 2012

Purpose: The pivot-shift phenomenon has been identified to be one of the essential signs of functional anterior cruciate ligament (ACL) insufficiency. However, the pivot-shift test remains a surgeon-subjective examination, lacking a general recognized quantitative measurement. The goal of the present study was to validate the use of an inertial sensor for quantifying the pivot-shift test, using a commercial navigation system. Methods: An expert surgeon intra-operatively performed the pivot-shift test on 15 consecutive patients before ACL reconstruction. A single accelerometer and a commercial navigation system simultaneously acquired limb kinematics. An additional optical tracker mounted on the accelerometer allowed following sensor movements. Anteroposterior (a-p) tibial acceleration obtained with the navigation system was compared with three-dimensional (3D) acceleration acquired by the accelerometer. The effect of skin artifacts and test-retest positioning were estimated. Repeatability of the acceleration parameter and waveform was analyzed. Correlation between the two measurements was also assessed. Results: Average root mean square (RMS) error in test-retest positioning reported a good value of 5.5 ± 2.9 mm. Mean RMS displacement due to soft tissue artifacts was 4.9 ± 2.6 mm. The analysis of acceleration range repetitions reported a good intra-tester repeatability (Cronbach's alpha = 0.86). Inter-patients similarity analysis showed a mean acceleration waveform correlation of 0.88 ± 0.14. The acceleration ranges demonstrated a good positive correlation between the two measurements (rs = 0.72, P < 0.05). Conclusion: This study showed good reliability of the new device and good correlation with the navigation system results. Therefore, the accelerometer is a valid method to assess dynamic joint laxity. Level of evidence: II. © 2012 Springer-Verlag.

Gualandi C.,University of Bologna | Govoni M.,University of Bologna | Foroni L.,University of Bologna | Valente S.,University of Bologna | And 6 more authors.
European Polymer Journal | Year: 2012

Disinfection of electrospun materials is commonly carried out by ethanol (EtOH) soaking. However, in the literature no systematic investigation on the effect of EtOH disinfection on scaffold properties is available. In this study electrospun poly(l-lactic acid) (PLLA) scaffolds were differently treated in EtOH and changes of fiber morphology, fiber surface topography and scaffold thermo-mechanical properties were evaluated. It was found that EtOH induced the formation of an amount of crystal phase, in the initially amorphous fibers, which depends on EtOH grade, soaking time and temperature. Completely amorphous PLLA (a-PLLA) and semicrystalline PLLA (sc-PLLA) scaffolds were produced by applying different EtOH treatments to as-spun PLLA scaffold. Compared to a-PLLA, sc-PLLA was stiffer and composed of fibers with rougher surface. Cell culture performed by using permanent cell line H9c2 demonstrated that changes of scaffold properties determined a different cell response, in particular in the expression of proteins correlated to cell motility and cell adhesion. © 2012 Elsevier Ltd. All rights reserved.

Zaffagnini S.,Laboratorio Of Biomeccanica E Innovazione Tecnologica | Lopomo N.,Laboratorio Of Biomeccanica E Innovazione Tecnologica | Lopomo N.,Laboratorio Of Nanobiotecnologie Nabi | Signorelli C.,Laboratorio Of Biomeccanica E Innovazione Tecnologica | And 6 more authors.
Clinics in Sports Medicine | Year: 2013

There has been an increased interest in the quantification of the knee laxity secondary to anterior cruciate ligament (ACL) injury. In clinical practice, the diagnosis is performed by clinical examination and magnetic resonance imaging analysis and confirmed arthroscopically. The pivot shift phenomenon has been identified as one of the essential signs of functional ACL insufficiency. A reliable system to adequately assess patients with ACL injury, quantifying the pivot shift test outcome, is needed. Several studies have been conducted in this regard but the proposed methods remain confined to a research area. The goal of this article is to summarize the actual knowledge and current concepts. © 2013 Elsevier Inc.

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