Human osteoblasts within soft peptide hydrogels promote mineralisation in vitro

Biomaterials that provide three-dimensional support networks for the culture of cells are being developed for a wide range of tissue engineering applications including the regeneration of bone. This study explores the potential of the versatile ionic-complementary peptide, FEFEFKFK, for such a purpose as this peptide spontaneously self-assembles into β-sheet-rich fibres that subsequently self-associate to form self-supporting hydrogels. Via simple live/dead cell assays, we demonstrated that 3 wt% hydrogels were optimal for the support of osteoblast cells. We went on to show that these cells are not only viable within the three-dimensional hydrogel but they also proliferate and produce osteogenic key proteins, that is, they behave like in vivo bone cells, over the 14-day period explored here. The gel elasticity increased over time when cells were present – in comparison to a decrease in control samples – indicating the deposition of matrix throughout the peptide scaffold. Moreover, significant quantities of calcium phosphate were deposited. Collectively, these data demonstrate that ionic-complementary octapeptides offer a suitable three-dimensional environment for osteoblastic cell function

Osteogenic differentiation of human mesenchymal stem cells promotes mineralization within a biodegradable peptide hydrogel

An attractive strategy for the regeneration of tissues has been the use of extracellular matrix analogous biomaterials. Peptide-based fibrillar hydrogels have been shown to mimic the structure of extracellular matrix offering cells a niche to undertake their physiological functions. In this study, the capability of an ionic-complementary peptide FEFEFKFK (F, E, and K are phenylalanine, glutamic acid, and lysine, respectively) hydrogel to host human mesenchymal stem cells in three dimensions and induce their osteogenic differentiation is demonstrated. Assays showed sustained cell viability and proliferation throughout the hydrogel over 12 days of culture and these human mesenchymal stem cells differentiated into osteoblasts simply upon addition of osteogenic stimulation. Differentiated osteoblasts synthesized key bone proteins, including collagen-1 (Col-1), osteocalcin, and alkaline phosphatase. Moreover, mineralization occurred within the hydrogel. The peptide hydrogel is a naturally biodegradable material as shown by oscillatory rheology and reversed-phase high-performance liquid chromatography, where both viscoelastic properties and the degradation of the hydrogel were monitored over time, respectively. These findings demonstrate that a biodegradable octapeptide hydrogel can host and induce the differentiation of stem cells and has the potential for the regeneration of hard tissues such as alveolar bon

Role of sheet-edge interactions in β-sheet self-assembling peptide hydrogels

Hydrogels’ hydrated fibrillar nature makes them the material of choice for the design and engineering of 3D scaffolds for cell culture, tissue engineering, and drug-delivery applications. One particular class of hydrogels which has been the focus of significant research is self-assembling peptide hydrogels. In the present work, we were interested in exploring how fiber–fiber edge interactions affect the self-assembly and gelation properties of amphipathic peptides. For this purpose, we investigated two β-sheet-forming peptides, FEFKFEFK (F8) and KFEFKFEFKK (KF8K), the latter one having the fiber edges covered by lysine residues. Our results showed that the addition of the two lysine residues did not affect the ability of the peptides to form β-sheet-rich fibers, provided that the overall charge carried by the two peptides was kept constant. However, it did significantly reduce edge-driven hydrophobic fiber–fiber associative interactions, resulting in reduced tendency for KF8K fibers to associate/aggregate laterally and form large fiber bundles and consequently network cross-links. This effect resulted in the formation of hydrogels with lower moduli but faster dynamics. As a result, KF8K fibers could be aligned only under high shear and at high concentration while F8 hydrogel fibers were found to align readily at low shear and low concentration. In addition, F8 hydrogels were found to fragment at high concentration because of the high aggregation state stabilizing the fiber bundles, resulting in fiber breakage rather than disentanglement and alignment

Leggibilit\ue0 e comprensione delle linee guida sull\u2019igiene delle mani: confronto tra le linee guida OMS(2009) e del CDC (2002)

Introduzione. L\u2019aggiornamento di una linea guida (LG) \ue8 fondamentale per garantire la validit\ue0 delle raccomandazioni. L\u2019aggiornamento per\uf2 dovrebbe essere reso esplicito e i cambiamenti fatti resi evidenti nel testo. Obiettivo. Confrontare le LG sull\u2019igiene delle mani dell\u2019Organizzazione Mondiale della Sanit\ue0 del 2009 e dei Centres for Disease Control del 2002, per identificare le discrepanze e le novit\ue0 introdotte. Risultati. Anche se comparabili per molte raccomandazioni, le LG del CDC e OMS usano una differente terminologia: nelle prime per lavaggio delle mani si intende quello con acqua e sapone, nelle seconde anche con sapone antimicrobico: ignorare il glossario pu\uf2 rendere ambigua l\u2019interpretazione. Vengono segnalati i problemi nell\u2019individuazione delle prove alla base delle raccomandazioni. Conclusioni. Si dovrebbe porre molta attenzione quando si decide di applicare una linea guida aggiornata e cercare di capire quali sono le novit\ue0 introdotte. Si raccomanda la necessit\ue0 di linee guida snelle e facili da consultare, dove vengono messi in luce in principali cambiamenti fatti

Familiari e badanti: nostri alleati o concorrenti?

Molte Regioni hanno affrontato con vari interventi il sostegno della permanenza a domicilio dei pazienti con malattie croniche invalidanti e bisogni assistenziali complessi. Tali interventi vanno dall\u2019accesso facilitato ai servizi di assistenza domiciliare integrata pubblici o convenzionati, o da forme di assistenza indiretta come l\u2019erogazione di un assegno di cura mensile, ad azioni di formazione rivolte ai soggetti con funzioni di caregiver. Alcune Regioni, in risposta alle richieste delle Associazioni di malati e familiari, hanno assunto delle decisioni per preparare e autorizzare i caregiver a svolgere attivit\ue0 sanitarie. In questo editoriale si propongono alcune riflessioni a partire da una iniziativa della Regione Emilia-Romagna, che ha sollevato un vivace dibattito e che vogliamo utilizzare come occasione per riflettere sui rapporti tra infermieri e caregiver: tematica sulla quale la professione ha molta esperienza nella pratica quotidiana, ma ha ancora molte pagine da scrivere per esplicitare come pensa di relazionarsi nella complessit\ue0 di bisogni e interventi di cui sempre pi\uf9 le famiglie si fanno carico e per cui rivendicano un ruolo pi\uf9 attiv

Il sistema grade

Il Grades of Recommendation, Assessment, Development and Evaluation Working Group (GRADE Working Group) ha sviluppato un sistema per graduare la qualit\ue0 delle prove di efficacia. Il GRADE \ue8 stato adottato da pi\uf9 di 20 organizzazioni, compresa l\u2019Organizzazione Mondiale della Sanit\ue0. La qualit\ue0 di una prova prevede che vengano presi in esame i problemi metodologici dello studio (qualit\ue0 metodologica), l\u2019orientamento dei risultati, l\u2019eterogeneit\ue0, la precisione della stima dell\u2019effetto, e il rischio di bias di pubblicazione, per ogni singolo esito valutato. Il sistema GRADE assegna 4 livelli di qualit\ue0: le sperimentazioni cliniche, che sono in cima alla piramide delle prove di efficacia, possono essere declassate se hanno problemi metodologici. Viene presentata una breve rassegna del sistema GRADE

Evaluation of a synthetic peptide-based bioink (PeptiInk Alpha 1) for in vitro 3D bioprinting of cartilage tissue models

Cartilage pathology in human disease is poorly understood and requires further research. Various attempts have been made to study cartilage pathologies using in vitro human cartilage models as an alternative for preclinical research. Three-dimensional (3D) bioprinting is a technique that has been used to 3D-bioprint cartilage tissue models in vitro using animal-derived materials such as gelatine or hyaluronan, which present challenges in terms of scalability, reproducibility, and ethical concerns. We present an assessment of synthetic self-assembling peptides as bioinks for bioprinted human in vitro cartilage models. Primary human chondrocytes were mixed with PeptiInk Alpha 1, 3D-bioprinted and cultured for 14 days, and compared with 3D chondrocyte pellet controls. Cell viability was assessed through LIVE/DEAD assays and DNA quantification. High cell viability was observed in the PeptiInk culture, while a fast decrease in DNA levels was observed in the 3D pellet control. Histological evaluation using hematoxylin and eosin staining and immunofluorescence labeling for SOX-9, collagen type II, and aggrecan showed a homogeneous cell distribution in the 3D-bioprinted PeptiInks as well as high expression of chondrogenic markers in both control and PeptiInk cultures. mRNA expression levels assessed by - qRT-PCR (quantitative real time-polymerase chain reaction) confirmed chondrogenic cell behavior. These data showed promise in the potential use of PeptiInk Alpha 1 as a bioprintable manufacturing material for human cartilage in vitro models

Competenze e ruoli dei laureati magistrali nella pratica quotidiana. Studio descrittivo multicentrico

Introduzione. Non si hanno molte informazioni su ruolo e attivit\ue0 degli infermieri dopo il conseguimento della laurea magistrale. Obiettivo. Documentare quali competenze acquisite nel Corso di Laurea Magistrale vengono utilizzate nella pratica quotidiana e i cambiamenti di ruolo dei laureati magistrali. Metodo. Studio descrittivo multicentrico su 7 coorti consecutive (dal 2004/2005 al 2011/2012) di laureati magistrali di 3 universit\ue0 del nord Italia. L\u2019applicazione delle competenze manageriali, didattiche, di ricerca e cliniche acquisite nel corso di studi ed i cambiamenti di ruolo sono stati rilevati attraverso un questionario semistrutturato. Risultati. Hanno partecipato 232/285 laureati. Duecentosei (88.8%) hanno dichiarato di aver applicato competenze manageriali, 178 (76.7%) didattiche, 122 (52.6%) cliniche e 115 (49.5%) di ricerca. Conclusi gli studi, 80 laureati (34.4%) hanno cambiato ruolo. Sono aumentati coloro che ricoprono un ruolo manageriale (da 89 a 212; + 123, 14.5%) e didattico (da 33 a 44, + 11, 4.8%) mentre sono diminuiti coloro che occupano un ruolo clinico (da 110 a 65, -45, -19.4%). I cambiamenti di ruolo si verificano tre anni dopo il conseguimento del titolo (p = 0.006) e la frequenza varia in base alle sedi di formazione (p = 0.018). Conclusioni. Se fino ad ora il principale ambito di lavoro dei laureati magistrali era nell\u2019area manageriale, con i cambiamenti dei bisogni delle organizzazioni, i piani di studio dovrebbero dare una maggiore attenzione alle competenze cliniche. Sarebbe utile descrivere le caratteristiche dei contesti che facilitano o ostacolano l\u2019utilizzo delle competenze acquisite e le progressioni di carriera

Corrigendum to "Biodegradation of polyester polyurethane during commercial composting and analysis of associated fungal communities" [Bioresour. Technol. 158 (2014) 374-377].

The authors regret to inform that the name of the second author was misspelt in the article. Please read the name as Petrus Nzerem instead of Petrus Nzeram. The corrected author name is shown above. The authors would like to apologise for any inconvenience caused

Designing Peptide/Graphene Hybrid Hydrogels through Fine-Tuning of Molecular Interactions

A recent strategy that has emerged for the design of increasingly functional hydrogels is the incorporation of nanofillers in order to exploit their specific properties to either modify the performance of the hydrogel or add functionality. The emergence of carbon nanomaterials in particular has provided great opportunity for the use of graphene derivatives (GDs) in biomedical applications. The key challenge when designing hybrid materials is the understanding of the molecular interactions between the matrix (peptide nanofibers) and the nanofiller (here GDs) and how these affect the final properties of the bulk material. For the purpose of this work, three gelling β-sheet-forming, self-assembling peptides with varying physiochemical properties and five GDs with varying surface chemistries were chosen to formulate novel hybrid hydrogels. First the peptide hydrogels and the GDs were characterized; subsequently, the molecular interaction between peptides nanofibers and GDs were probed before formulating and mechanically characterizing the hybrid hydrogels. We show how the interplay between electrostatic interactions, which can be attractive or repulsive, and hydrophobic (and π–π in the case of peptide containing phenylalanine) interactions, which are always attractive, play a key role on the final properties of the hybrid hydrogels. The shear modulus of the hydrid hydrogels is shown to be related to the strength of fiber adhesion to the flakes, the overall hydrophobicity of the peptides, as well as the type of fibrillar network formed. Finally, the cytotoxicity of the hybrid hydrogel formed at pH 6 was also investigated by encapsulating and culturing human mesemchymal stem cells (hMSC) over 14 days. This work clearly shows how interactions between peptides and GDs can be used to tailor the mechanical properties of the resulting hydrogels, allowing the incorporation of GD nanofillers in a controlled way and opening the possibility to exploit their intrinsic properties to design novel hybrid peptide hydrogels for biomedical applications