Modeling mechanical signals on the surface of µCT and CAD based rapid prototype scaffold models to predict (early stage) tissue development.

In the field of tissue engineering, mechano-regulation theories have been applied to help predict tissue development in tissue engineering scaffolds in the past. For this, finite element models (FEMs) were used to predict the distribution of strains within a scaffold. However, the strains reported in these studies are volumetric strains of the material or strains developed in the extracellular matrix occupying the pore space. The initial phase of cell attachment and growth on the biomaterial surface has thus far been neglected. In this study, we present a model that determines the magnitude of biomechanical signals on the biomaterial surface, enabling us to predict cell differentiation stimulus values at this initial stage. Results showed that magnitudes of the 2D strain--termed surface strain--were lower when compared to the 3D volumetric strain or the conventional octahedral shear strain as used in current mechano-regulation theories. Results of both µCT and CAD derived FEMs from the same scaffold were compared. Strain and fluid shear stress distributions, and subsequently the cell differentiation stimulus, were highly dependent on the pore shape. CAD models were not able to capture the distributions seen in the µCT FEM. The calculated mechanical stimuli could be combined with current mechanobiological models resulting in a tool to predict cell differentiation in the initial phase of tissue engineering. Although experimental data is still necessary to properly link mechanical signals to cell behavior in this specific setting, this model is an important step towards optimizing scaffold architecture and/or stimulation regimes.

Amorphous magnesium phosphate-graphene oxide nano particles laden 3D-printed chitosan scaffolds with enhanced osteogenic potential and antibacterial properties.

The utilization of 3D printing technology for the fabrication of graft substitutes in bone repair holds immense promise. However, meeting the requirements for printability, bioactivity, mechanical strength, and biological properties of 3D printed structures concurrently poses a significant challenge. In this study, we introduce a novel approach by incorporating amorphous magnesium phosphate-graphene oxide (AMP-GO) into a thermo-crosslinkable chitosan/ß glycerol phosphate (CS/GP) ink. We fabricated thermo-crosslinkable CS inks containing varying concentrations (10 %, 20 %, or 30 % weight) of AMP-GO. The 3D printed scaffolds incorporating 20 % AMP-GO exhibited significantly improved mechanical properties, with compressive strengths of 4.5 ± 0.06 MPa compared to 0.5 ± 0.03 MPa for CS printed scaffolds. Moreover, the CS/AMP-GO inks demonstrated enhanced antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria, attributed to the release of magnesium cations and the performance of GO. Additionally, CS/20AMP-GO ink facilitated increased adhesion, viability, proliferation, and osteogenic differentiation of mesenchymal stem cells (MSCs), as evidenced by the upregulation of ALP, COL1, and Runx2 expression, which were elevated 9.8, 6.5, and >22 times, respectively, compared to pure CS scaffolds. Considering its exceptional in vivo osteogenic potential, we anticipate that the CS/20AMP-GO ink holds great potential for 3D printing of bone grafts.

A facile strategy for tuning the density of surface-grafted biomolecules for melt extrusion-based additive manufacturing applications.

Melt extrusion-based additive manufacturing (ME-AM) is a promising technique to fabricate porous scaffolds for tissue engineering applications. However, most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell fate. Grafting of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct; however, there are limited strategies available to control the surface density. Here, we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k (PCL5k) containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different ratios. Stable porous three-dimensional (3D) scaffolds were then fabricated using a high weight percentage (75 wt.%) of the low molecular weight PCL5k. As a proof-of-concept test, we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface, yielding a density of 201-561 pmol/cm2. Subsequently, a bone morphogenetic protein 2 (BMP-2)-derived peptide was grafted onto the films comprising different blend compositions, and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells (hMSCs) was assessed. After two weeks of culturing in a basic medium, cells expressed higher levels of BMP receptor II (BMPRII) on films with the conjugated peptide. In addition, we found that alkaline phosphatase activity was only significantly enhanced on films containing the highest peptide density (i.e., 561 pmol/cm2), indicating the importance of the surface density. Taken together, these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material interface. Moreover, we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of (modified) polymers. Furthermore, the use of alkyne-azide "click" chemistry enables spatial control over bioconjugation of many tissue-specific moieties, making this approach a versatile strategy for tissue engineering applications. Supplementary Information: The online version contains supplementary material available at 10.1007/s42242-024-00286-2.

Ultrahigh-water-content biocompatible gelatin-based hydrogels: Toughened through micro-sized dissipative morphology as an effective strategy.

Fabrication of simultaneously robust and superabsorbent gelatin-based hydrogels for biomedical applications still remains a challenge due to lack of locally dissipative points in the presence of large water content. Here, we apply a synthesis strategy through which water absorbency and energy dissipative points are separated, and toughening mechanism is active closely at the crack tip. For this, gelatin-based microgels (GeMs) were synthesized in a way that concentrated supramolecular interactions were present to increase the energy necessary to propagate a macroscopic crack. The microgels were interlocked to each other via both temporary hydrophobic associations and permanent covalent crosslinks, in which the sacrificial binds sustained the toughness due to the mobility of the junction zones and particles sliding. However, chemical crosslinking points preserved the integrity and fast recoverability of the hydrogel. Hysteresis increased strongly with increasing supramolecular interactions within the network. The prepared hydrogels showed energy loss and swelling ratio up to 3440 J. m-3 and 830%, respectively, which was not achievable with conventional network fabrication methods. The microgels were also assessed for their in vivo biocompatibility in a rat subcutaneous pocket assay. Results of hematoxylin and eosin (H&E) staining demonstrated regeneration of the tissue around the scaffolds without incorporation of growth factors. Also, vascularization within the scaffolds was observed after 4 weeks implantation. These results indicate that our strategy is a promising method to manipulate those valuable polymers, which lose their toughness and applicability with increasing their water content.

3D porous Ti6Al4V-beta-tricalcium phosphate scaffolds directly fabricated by additive manufacturing.

3D Ti6Al4V-beta-tricalcium phosphate (TCP) hybrid scaffolds with interconnected porous network and controllable porosity and pore size were successfully produced by three-dimensional fiber deposition (3DF). The macrostructure of scaffolds was determined by the 3D design, whereas the micro- and submicron structure were derived from the Ti6Al4V powder sintering and the crystalline TCP powder, respectively. Ti6Al4V-TCP slurry was developed for 3DF by optimizing the TCP powder size, Ti6Al4V-to-TCP powder ratio and Ti6Al4V-TCP powder content. Moreover, the air pressure and fiber deposition rate were optimized. A maximum achievable ceramic content in the Ti6Al4V-TCP slurry that enables 3DF manufacturing was 10 wt%. The chemical analysis showed that limited contamination occurred during sintering. The compressive strength and Young's modulus of the scaffolds exhibited values between those of cancellous and cortical bone. The 3D Ti6Al4V-TCP scaffolds with 10 wt% TCP allowed deposition of a calcium phosphate layer on the surface in a simulated body fluid. Cumulative release of calcium and phosphate ions from the scaffolds was observed in a simulated physiological solution, in contrast to a cell culture medium. A pilot in vivo study, in which the scaffolds were implanted intramuscularly in dogs showed ectopic bone formation in the Ti6Al4V-TCP scaffolds with 10 wt% TCP, showing their osteoinductive potential. The porous 3D Ti6Al4V-TCP scaffolds developed here combine the mechanical properties of the metal with the bioactivity of the ceramic and are therefore likely to yield more effective strategies to control the implant-bone interface and thereby improve long-term clinical results in orthopaedics and craniomaxillofacial surgery. STATEMENT OF SIGNIFICANCE: In this work, 3D porous hybrid scaffolds made of a titanium alloy and a beta-tricalcium phosphate ceramic (Ti6Al4V-TCP) were developed using the direct additive manufacturing technique 3D fiber deposition. Upon optimization of the powders and slurry, scaffolds with up to 10 wt.% TCP with good mechanical properties and controllable porous structure at different length scales were successfully manufactured. A preliminary in vivo study in an intramuscular model demonstrated that the addition of TCP to the metal alloy improved its bioactivity. The combination of the two materials and the use of a direct additive manufacturing technique resulted in scaffolds that may lead to more effective strategies to control the implant-bone interface and thereby improve long-term clinical results in orthopaedics and craniomaxillofacial surgery.

Additive manufactured, highly resilient, elastic, and biodegradable poly(ester)urethane scaffolds with chondroinductive properties for cartilage tissue engineering.

Articular cartilage was thought to be one of the first tissues to be successfully engineered. Despite the avascular and non-innervated nature of the tissue, the cells within articular cartilage - chondrocytes - account for a complex phenotype that is difficult to be maintained in vitro. The use of bone marrow-derived stromal cells (BMSCs) has emerged as a potential solution to this issue. Differentiation of BMSCs toward stable and non-hypertrophic chondrogenic phenotypes has also proved to be challenging. Moreover, hyaline cartilage presents a set of mechanical properties - relatively high Young's modulus, elasticity, and resilience - that are difficult to reproduce. Here, we report on the use of additive manufactured biodegradable poly(ester)urethane (PEU) scaffolds of two different structures (500 µm pore size and 90° or 60° deposition angle) that can support the loads applied onto the knee while being highly resilient, with a permanent deformation lower than 1% after 10 compression-relaxation cycles. Moreover, these scaffolds appear to promote BMSC differentiation, as shown by the deposition of glycosaminoglycans and collagens (in particular collagen II). At gene level, BMSCs showed an upregulation of chondrogenic markers, such as collagen II and the Sox trio, to higher or similar levels than that of traditional pellet cultures, with a collagen II/collagen I relative expression of 2-3, depending on the structure of the scaffold. Moreover, scaffolds with different pore architectures influenced the differentiation process and the final BMSC phenotype. These data suggest that additive manufactured PEU scaffolds could be good candidates for cartilage tissue regeneration in combination with microfracture interventions.

A novel method for engineering autologous non-thrombogenic in situ tissue-engineered blood vessels for arteriovenous grafting.

The durability of prosthetic arteriovenous (AV) grafts for hemodialysis access is low, predominantly due to stenotic lesions in the venous outflow tract and infectious complications. Tissue engineered blood vessels (TEBVs) might offer a tailor-made autologous alternative for prosthetic grafts. We have designed a method in which TEBVs are grown in vivo, by utilizing the foreign body response to subcutaneously implanted polymeric rods in goats, resulting in the formation of an autologous fibrocellular tissue capsule (TC). One month after implantation, the polymeric rod is extracted, whereupon TCs (length 6 cm, diameter 6.8 mm) were grafted as arteriovenous conduit between the carotid artery and jugular vein of the same goats. At time of grafting, the TCs were shown to have sufficient mechanical strength in terms of bursting pressure (2382 ±â€¯129 mmHg), and suture retention strength (SRS: 1.97 ±â€¯0.49 N). The AV grafts were harvested at 1 or 2 months after grafting. In an ex vivo whole blood perfusion system, the lumen of the vascular grafts was shown to be less thrombogenic compared to the initial TCs and ePTFE grafts. At 8 weeks after grafting, the entire graft was covered with an endothelial layer and abundant elastin expression was present throughout the graft. Patency at 1 and 2 months was comparable with ePTFE AV-grafts. In conclusion, we demonstrate the remodeling capacity of cellularized in vivo engineered TEBVs, and their potential as autologous alternative for prosthetic vascular grafts.

Lab-on-a-brane for spheroid formation.

Lab-On-a-Brane (LOB) represents a class of Lab-On-a-Chip (LOC) integrating flexible, highly gas permeable and biocompatible thin membranes (TMs). Here we demonstrate the potentiality of LOBs as cell biochips promoting 3D cell growth. The human cancer cells MCF-7 were cultured into standard multiwells (MWs) and into polydimethylsiloxane (PDMS) MWs, LOCs, and LOBs of different wettability. Surface treatments based on oxygen plasma and coating deposition have been performed to produce hydrophilic, hydrophobic, and oleophobic chips. By a comparison between all these chips, we observed that 3D cell aggregation is favored in LOBs, independent of substrate wettability. This may be attributed to the TM flexibility and the high oxygen/carbon dioxide permeability. Ultimately, LOBs seem to combine the advantages of LOCs as multi-well microfluidic chips to reduce operation time for cell seeding and medium refresh, with the mechanical/morphological properties of PDMS TMs. This is convenient in the perspective of applying mechanical stimuli and monitoring cell stiffness, or studying the metabolism of molecules permeable to PDMS membrane in response to external stimuli with interesting outcomes in cellular biology.

Shape-defined solid micro-objects from poly(d,l-lactic acid) as cell-supportive counterparts in bottom-up tissue engineering.

In bottom-up tissue engineering, small modular units of cells and biomaterials are assembled toward â€‹larger and more complex ones. In conjunction with a new implementation of this approach, a novel method to fabricate microscale objects from biopolymers by thermal imprinting on water-soluble sacrificial layers is presented. By this means, geometrically well-defined objects could be obtained without involving toxic agents in the form of photoinitiators. The micro-objects were used as cell-adhesive substrates and cell spacers in engineered tissues created by cell-guided assembly of the objects. Such constructs can be applied both for in vitro studies and clinical treatments. Clinically relevantly sized aggregates comprised of cells and micro-objects retained their viability up to 2 weeks of culture. The aggregation behavior of cells and objects showed to depend on the type and number of cells applied. To demonstrate the micro-objects' potential for engineering vascularized tissues, small aggregates of human bone marrow stromal cells (hMSCs) and micro-objects were coated with a layer of human umbilical vein endothelial cells (HUVECs) and fused into larger tissue constructs, resulting in HUVEC-rich regions at the aggregates' interfaces. This three-dimensional network-type spatial cellular organization could foster the establishment of (premature) vascular structures as a vital prerequisite of, for example, bottom-up-engineered bone-like tissue.

Critical factors in the design of growth factor releasing scaffolds for cartilage tissue engineering.

BACKGROUND: Trauma or degenerative diseases of the joints are common clinical problems resulting in high morbidity. Although various orthopedic treatments have been developed and evaluated, the low repair capacities of articular cartilage renders functional results unsatisfactory in the long term. Over the last decade, a different approach (tissue engineering) has emerged that aims not only to repair impaired cartilage, but also to fully regenerate it, by combining cells, biomaterials mimicking extracellular matrix (scaffolds) and regulatory signals. The latter is of high importance as growth factors have the potency to induce, support or enhance the growth and differentiation of various cell types towards the chondrogenic lineage. Therefore, the controlled release of different growth factors from scaffolds appears to have great potential to orchestrate tissue repair effectively. OBJECTIVE: This review aims to highlight considerations and limitations of the design, materials and processing methods available to create scaffolds, in relation to the suitability to incorporate and release growth factors in a safe and defined manner. Furthermore, the current state of the art of signalling molecules release from scaffolds and the impact on cartilage regeneration in vitro and in vivo is reported and critically discussed. METHODS: The strict aspects of biomaterials, scaffolds and growth factor release from scaffolds for cartilage tissue engineering applications are considered. CONCLUSION: Engineering defined scaffolds that deliver growth factors in a controlled way is a task seldom attained. If growth factor delivery appears to be beneficial overall, the optimal delivery conditions for cartilage reconstruction should be more thoroughly investigated.

[Italian validation of the Prolonged Grief Disorder Questionnaire (PG-12)]. / Validazione italiana del Questionario Prolonged Grief Disorder (PG-12).

Death or severe invalidity (e.g. vegetative state) of a family member causes deep emotional distress to the caregiver. In most cases elaboration of mourning at the loss unfolds in physiological times and modes, enabling the caregiver to react to the separation and resume their own daily life. In some cases, however, there is an incapacity to react and caregivers remain imprisoned in a condition they are unable to elaborate consisting of memories, regrets and a sense of guilt, that leads to their self isolation and prevents them from leading a full life as prior to the grief-causing event. This condition, not always classifiable as a major depressive disorder, is, according to a recent debate, more adequately described as the "Prolonged Grief Disorder". The Prolonged Grief Disorder is a new diagnostic category, currently under examination in America for inclusion in the DSM V in order to give clinicians a picture that better describes the condition of these caregivers. The PG-12 is a questionnaire that is easy and quick to administer and score which can guide the clinician in the diagnosis of this condition. The present paper presents the methodology followed for the translation into Italian of this instrument and the data that emerged concerning its validity and applicability. 45 caregivers of vegetative state patients were enrolled. The PG-12 Italian version showed good internal consistency (Cronbach alpha = 0.88) and a mono factorial structure.

[Caregiver Need Assessment: a questionnaire for caregiver demand]. / Caregiver Need Assessment: uno strumento di analisi dei bisogni del caregiver.

UNLABELLED: Many studies have focused on the importance of the informal care provided by caregivers and on its impact in terms of worsening quality of life and increased burden. The aim of the present study is to analyze the psychometric validity and reliability of the Caregiver Needs Assessment (CNA) questionnaire, which has been built to investigate the needs (related to assistance) perceived by caregivers of severely impaired patients, particularly in the first stages of their illness. METHODS: The CNA was administered to 226 family caregivers (24.3% males) of 197 patients (50.8% males) hospitalized for neuromotor rehabilitation after a stroke, head injury, Lateral Amyotrophic Sclerosis, Parkinson or other severely impairing diseases. RESULTS: The instrument was tested on a large sample (KMO = 0.83) of heterogeneous caregivers. Explorative and confirmatory factor analysis, performed on a two subgroup random subdivision of the sample, showed the presence of two factors with good internal consistency: the factor "needs of emotional and social support" (alpha = 0.765) and the factor "needs of information and communication" (alpha = 0.742). The structural equation modeling confirms the goodness of fit of the 2-factor structure (RMSEA = 0.073; SRMR = 0.1; CFI = 0.96). We observed a positive correlation (p < 0.01) between the factor "needs of emotional and social support" of the CNA and other questionnaires aimed at assessing psychological wellbeing, and between the factor "needs of information and communication" and the factor "needs for knowledge about the disease" of the Family Strain Questionnaire, showing good convergent validity. We also observed high Pearson correlation coefficients (0.942 and 0.965) between test-retest measurements of both factors in the CNA. CONCLUSION: The statistical analysis confirms the good psychometric properties of the CNA questionnaire. For its brevity and ease in compilation the CNA is promising practical tool aimed at assessing caregivers' needs in order to personalize a programme of psychological support, to measure it's outcome and to provide comparison of the different needs in different diseases.

Design of biphasic polymeric 3-dimensional fiber deposited scaffolds for cartilage tissue engineering applications.

This report describes a novel system to create rapid prototyped 3-dimensional (3D) fibrous scaffolds with a shell-core fiber architecture in which the core polymer supplies the mechanical properties and the shell polymer acts as a coating providing the desired physicochemical surface properties. Poly[(ethylene oxide) terephthalate-co-poly(butylene) terephthalate] (PEOT/PBT) 3D fiber deposited (3DF) scaffolds were fabricated and examined for articular cartilage tissue regeneration. The shell polymer contained a higher molecular weight of the initial poly(ethylene glycol) (PEG) segments used in the copolymerization and a higher weight percentage of the PEOT domains compared with the core polymer. The 3DF scaffolds entirely produced with the shell or with the core polymers were also considered. After 3 weeks of culture, scaffolds were homogeneously filled with cartilage tissue, as assessed by scanning electron microscopy. Although comparable amounts of entrapped chondrocytes and of extracellular matrix formation were found for all analyzed scaffolds, chondrocytes maintained their rounded shape and aggregated during the culture period on shell-core 3DF scaffolds, suggesting a proper cell differentiation into articular cartilage. This finding was also observed in the 3DF scaffolds fabricated with the shell composition only. In contrast, cells spread and attached on scaffolds made simply with the core polymer, implying a lower degree of differentiation into articular cartilaginous tissue. Furthermore, the shell-core scaffolds displayed an improved dynamic stiffness as a result of a "prestress" action of the shell polymer on the core one. In addition, the dynamic stiffness of the constructs increased compared with the stiffness of the bare scaffolds before culture. These findings suggest that shell-core 3DF PEOT/PBT scaffolds with desired mechanical and surface properties are a promising solution for improved cartilage tissue engineering.

[A "I would like to give him my life": results of a psychological support intervention to caregivers of patients undergoing neuromotor rehabilitation]. / "Vorrei regalargli la mia vita": risultati di un progetto di supporto psicologico ai caregiver di pazienti in riabilitazione neuromotoria.

A large proportion of patients hospitalised for severe neuromotor disorders are supported during the in-hospital rehabilitation program by family members. To target interventions of psychological support for these caregivers it can be of help to identify the causes of caregiver burden or specific needs. Anxiety and depression are common in caregivers and constitute, together with emotional distress caused by loneliness and reduced social activities, an important part of the caregiving burden. This paper presents results emerging from a clinical intervention of psychological support offered to caregivers of neuromotor patients, mainly post-stroke, who were undergoing a course of in-hospital rehabilitation. A psychometric assessment was carried out on a sample of 50 caregivers, spouses or children, at the beginning and end of the in-hospital rehabilitation period. The following questionnaires were used: the Revised Anxiety and Depression Scale (RADS), measuring anxiety and depression, the Caregiver Need Assessment (CNA), assessing needs related to the assisted patient, and the Family Strain Questionnaire (FSQ) for a broader assessment of the problems faced by caregivers. The Functional Independence Measure (FIM) was completed by the medical doctor. A significant reduction was found, between the beginning and end of the rehabilitation period, in the needs related to patient care on the CNA (p < 0.001). Caregiver females, in contrast to males, showed an improvement in mood compared to the beginning of the rehabilitation period (p < 0.05). About half of the sample had, at the beginning, a marked clinical level of anxiety while 22% of caregivers had a marked clinical level of depression. Caregivers who received intense psychological support, i.e. at least one interview with the psychologist per week, showed, in contrast to those who received 3-4 interviews during the entire rehabilitation period, a decline in thoughts of death (p < 0.05) and, in cases where baseline anxiety was above the clinical cut-off, a reduced level of anxiety (p < 0.05). At the beginning of rehabilitation, there emerged: higher anxiety scores in caregivers who live with their patient (p < 0.05) compared to those living alone or with others; an increase in depression scores in inverse proportion to the patient's age (p = 0.01); higher scores of emotional stress in spouses (p < 0.05) compared to children and in caregivers of patients with left hemisphere deficits (p < 0.05); a greater need for knowledge about the disease (p < 0.001) and more thoughts of death (p < 0.05) in caregivers of female patients. These characteristics may be considered "alarm signals" that should alert hospital medical staff to the need to seek psychological help for the caregiver. At the end of rehabilitation, a greater degree of psychological strain was observed in caregivers of patients with severe disability. High needs related to the assisted patient (p < 0.01), high scores of emotional stress (p < 0.05), problems of social involvement (p < 0.05) and thoughts of death about the patient (p < 0.05) were found in caregivers of patients who had persisting high motor disability or who were admitted for consequences of a left hemisphere lesion. High depression scores were also found in caregivers of patients with high residual cognitive disability (p < 0.05). This psychometric evaluation makes it possible to tailor the psychological support offered to the needs of each individual caregiver both during rehabilitation and in relation to eventual future developments. A multidisciplinary team approach to the caregiver can thus lead to a general reduction of caregiver strain.

3D screening device for the evaluation of cell response to different electrospun microtopographies.

Micro- and nano-topographies of scaffold surfaces play a pivotal role in tissue engineering applications, influencing cell behavior such as adhesion, orientation, alignment, morphology and proliferation. In this study, a novel microfabrication method based on the combination of soft-lithography and electrospinning for the production of micro-patterned electrospun scaffolds was proposed. Subsequently, a 3D screening device for electrospun meshes with different micro-topographies was designed, fabricated and biologically validated. Results indicated that the use of defined patterns could induce specific morphological variations in human mesenchymal stem cell cytoskeletal organization, which could be related to differential activity of signaling pathways. STATEMENT OF SIGNIFICANCE: We introduce a novel and time saving method to fabricate 3D micropatterns with controlled micro-architectures on electrospun meshes using a custom made collector and a PDMS mold with the desired topography. A possible application of this fabrication technique is represented by a 3D screening system for patterned electrospun meshes that allows the screening of different scaffold/electrospun parameters on cell activity. In addition, what we have developed in this study could be modularly applied to existing platforms. Considering the different patterned geometries, the cell morphological data indicated a change in the cytoskeletal organization with a close correspondence to the patterns, as shown by phenoplot and boxplot analysis, and might hint at the differential activity of cell signaling. The 3D screening system proposed in this study could be used to evaluate topographies favoring cell alignment, proliferation and functional performance, and has the potential to be upscaled for high-throughput.

3D fiber-deposited scaffolds for tissue engineering: influence of pores geometry and architecture on dynamic mechanical properties.

One of the main issues in tissue engineering is the fabrication of scaffolds that closely mimic the biomechanical properties of the tissues to be regenerated. Conventional fabrication techniques are not sufficiently suitable to control scaffold structure to modulate mechanical properties. Within novel scaffold fabrication processes 3D fiber deposition (3DF) showed great potential for tissue engineering applications because of the precision in making reproducible 3D scaffolds, characterized by 100% interconnected pores with different shapes and sizes. Evidently, these features also affect mechanical properties. Therefore, in this study we considered the influence of different structures on dynamic mechanical properties of 3DF scaffolds. Pores were varied in size and shape, by changing fibre diameter, spacing and orientation, and layer thickness. With increasing porosity, dynamic mechanical analysis (DMA) revealed a decrease in elastic properties such as dynamic stiffness and equilibrium modulus, and an increase of the viscous parameters like damping factor and creep unrecovered strain. Furthermore, the Poisson's ratio was measured, and the shear modulus computed from it. Scaffolds showed an adaptable degree of compressibility between sponges and incompressible materials. As comparison, bovine cartilage was tested and its properties fell in the fabricated scaffolds range. This investigation showed that viscoelastic properties of 3DF scaffolds could be modulated to accomplish mechanical requirements for tailored tissue engineered applications.

Dynamic mechanical properties of 3D fiber-deposited PEOT/PBT scaffolds: an experimental and numerical analysis.

Mechanical properties of three-dimensional (3D) scaffolds can be appropriately modulated through novel fabrication techniques like 3D fiber deposition (3DF), by varying scaffold's pore size and shape. Dynamic stiffness, in particular, can be considered as an important property to optimize the scaffold structure for its ultimate in vivo application to regenerate a natural tissue. Experimental data from dynamic mechanical analysis (DMA) reveal a dependence of the dynamic stiffness of the scaffold on the intrinsic mechanical and physicochemical properties of the material used, and on the overall porosity and architecture of the construct. The aim of this study was to assess the relationship between the aforementioned parameters, through a mathematical model, which was derived from the experimental mechanical data. As an example of how mechanical properties can be tailored to match the natural tissue to be replaced, articular bovine cartilage and porcine knee meniscus cartilage dynamic stiffness were measured and related to the modeled 3DF scaffolds dynamic stiffness. The dynamic stiffness of 3DF scaffolds from poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT) copolymers was measured with DMA. With increasing porosity, the dynamic stiffness was found to decrease in an exponential manner. The influence of the scaffold architecture (or pore shape) and of the molecular network properties of the copolymers was expressed as a scaffold characteristic coefficient alpha, which modulates the porosity effect. This model was validated through an FEA numerical simulation performed on the structures that were experimentally tested. The relative deviation between the experimental and the finite element model was less than 15% for all of the constructs with a dynamic stiffness higher than 1 MPa. Therefore, we conclude that the mathematical model introduced can be used to predict the dynamic stiffness of a porous PEOT/PBT scaffold, and to choose the biomechanically optimal structure for tissue engineering applications.

[Anxiety and Depression Short Scale: norms for its use in rehabilitation]. / Scheda ansia e depressione forma ridotta: norme per l'utilizzo in ambito riabilitativo.

In the rehabilitation setting it is important to identify clinically significant conditions of distress so as to be able to provide, in addition to the conventional multidisciplinary rehabilitation treatment, specific psychotherapeutic interventions targeted to the individual's problems. This paper presents the findings from a psychometric test for the measurement of anxiety and depression (AD-R Scale) administered at the start and end of a rehabilitation program in patients with cardiopulmonary disease. The study population consisted of 765 patients affected by cardiac and pulmonary disease undergoing an in-hospital course of intensive rehabilitation. We observed that AD-R scores are related to sex, age and diseases. Among anxiety and depression scores there are statistically significant differences regarding sex: women achieved higher AD-R scores compared with men. Depression scores are influenced by age: younger subjects reached lower scores compared with the older ones. Among patients with respiratory disease, the subjects affected by chronic respiratory failure showed statistically significant higher depression scores compared to subjects affected by chronic obstructive pulmonary disease and bronchial asthma. Anxiety and depression scores among subjects affected by cardiac diseases did not show important differences. At the end of the multidisciplinary rehabilitation program, a significant reduction in both anxiety and depression scores was observed, compared to values at the start, particularly for those that, at the beginning of the rehabilitation program, reached clinically remarkable AD-R scores and in general for the youngest subjects. The paper also presents the means, standard deviations and percentile range of scores for anxiety and depression in the population studied, according to age, sex, underlying pathology or hospital division. The Scale AD-R appears to be a valid instrument for the screening of patients undergoing cardio-pulmonary rehabilitation and as an outcome index.

Increased cell seeding efficiency in bioplotted three-dimensional PEOT/PBT scaffolds.

In regenerative medicine studies, cell seeding efficiency is not only optimized by changing the chemistry of the biomaterials used as cell culture substrates, but also by altering scaffold geometry, culture and seeding conditions. In this study, the importance of seeding parameters, such as initial cell number, seeding volume, seeding concentration and seeding condition is shown. Human mesenchymal stem cells (hMSCs) were seeded into cylindrically shaped 4 × 3 mm polymeric scaffolds, fabricated by fused deposition modelling. The initial cell number ranged from 5 × 10(4) to 8 × 10(5) cells, in volumes varying from 50 µl to 400 µl. To study the effect of seeding conditions, a dynamic system, by means of an agitation plate, was compared with static culture for both scaffolds placed in a well plate or in a confined agarose moulded well. Cell seeding efficiency decreased when seeded with high initial cell numbers, whereas 2 × 10(5) cells seemed to be an optimal initial cell number in the scaffolds used here. The influence of seeding volume was shown to be dependent on the initial cell number used. By optimizing seeding parameters for each specific culture system, a more efficient use of donor cells can be achieved. Copyright © 2013 John Wiley & Sons, Ltd.