Modification of β-Sheet Forming Peptide Hydrophobic Face: Effect on Self-Assembly and Gelation

β-Sheet forming peptides have attracted significant interest for the design of hydrogels for biomedical applications. One of the main challenges is the control and understanding of the correlations between peptide molecular structure, the morphology, and topology of the fiber and network formed as well as the macroscopic properties of the hydrogel obtained. In this work, we have investigated the effect that functionalizing these peptides through their hydrophobic face has on their self-assembly and gelation. Our results show that the modification of the hydrophobic face results in a partial loss of the extended β-sheet conformation of the peptide and a significant change in fiber morphology from straight to kinked. As a consequence, the ability of these fibers to associate along their length and form large bundles is reduced. These structural changes (fiber structure and network topology) significantly affect the mechanical properties of the hydrogels (shear modulus and elasticity)

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

Clinical Learning Environment and Supervision plus nurse Teacher (CLES+T) scale: testing the psychometric characteristics of the Italian version.

A clinical learning environment is an \u201cinteractive network of forces within the clinical setting that influence the students\u2019 learning outcomes\u201d. International research indicates the Clinical Learning Environment, Supervision and Nurse Teacher scale (CLES+T) as the gold standard tool to assess the forces involved in defining a good clinical learning environment. This study aimed to evaluate the psychometric proprieties of CLES+T Italian version. 875 Bachelor in Nursing students in 3 Universities in Italy partecipated in the study. Cronbach\u2019s alpha, item to total correlations, shape indexes were calculated and factor analysis was performed using Principal Axis Factoring and an oblique rotation method. Results showed an internal reliability for the total scale of 0.95, with subscales ranging from 0.80 to 0.96 among factors; all items add value to the scale and the distribution of answers have good shape indexes. Factor analysis showed a 7-factors model as explaining more than 67% of the variance, the higher variance was found in the \u201cpedagogical atmosphere\u201d factor (37.61%). The nurse teacher factor in the Italian model is split into 3 sub-factors: theory-practice integration, cooperation with ward staff and relationship with mentor and student. These results enable an international debate concerning the theoretical structure of CLES+T and enable a wider comparison on supervisory models in guiding students\u2019 clinical learning

Moving forward the Italian nursing education into the post-pandemic era: findings from a national qualitative research study

Background: During the CoronaVIrus-19 (COVID-19) pandemic, nursing education has been dramatically transformed and shaped according to the restrictions imposed by national rules. Restoring educational activities as delivered in the pre-pandemic era without making a critical evaluation of the transformations implemented, may sacrifice the extraordinary learning opportunity that this event has offered. The aim of this study was to identify a set of recommendations that can guide the Italian nursing education to move forward in the post-pandemic era. Methods: A qualitative descriptive design was undertaken in 2022–2023 and reported here according to the COnsolidated criteria for REporting Qualitative research guidelines. A network was established of nine Italian universities offering a bachelor’s degree in nursing for a total of 6135 students. A purposeful sample of 37 Faculty Members, 28 Clinical Nurse Educators and 65 Students/new graduates were involved. A data collection was conducted with a form including open-ended questions concerning which transformations in nursing education had been implemented during the pandemic, which of these should be maintained and valued, and what recommendations should address the transition of nursing education in the post-pandemic era. Results: Nine main recommendations embodying 18 specific recommendations have emerged, all transversally influenced by the role of the digital transformation, as a complementary and strengthening strategy for face-to-face teaching. The findings also suggest the need to rethink clinical rotations and their supervision models, to refocus the clinical learning aims, to pay attention towards the student community and its social needs, and to define a pandemic educational plan to be ready for unexpected, but possible, future events. Conclusions: A multidimensional set of recommendations emerged, shaping a strategic map of action, where the main message is the need to rethink the whole nursing education, where digitalization is embodied. Preparing and moving nursing education forward by following the emerged recommendations may promote common standards of education and create the basis on for how to deal with future pandemic/catastrophic events by making ready and prepared the educational systems

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

Controlling Doxorubicin Release from a Peptide Hydrogel through Fine-Tuning of Drug–Peptide Fiber Interactions

open access articleHydrogels are versatile materials that have emerged in the last few decades as promising candidates for a range of applications in the biomedical field, from tissue engineering and regenerative medicine to controlled drug delivery. In the drug delivery field, in particular, they have been the subject of significant interest for the spatially and temporally controlled delivery of anticancer drugs and therapeutics. Self-assembling peptide-based hydrogels, in particular, have recently come to the fore as potential candidate vehicles for the delivery of a range of drugs. In order to explore how drug–peptide interactions influence doxorubicin (Dox) release, five β-sheet-forming self-assembling peptides with different physicochemical properties were used for the purpose of this study, namely: FEFKFEFK (F8), FKFEFKFK (FK), FEFEFKFE (FE), FEFKFEFKK (F8K), and KFEFKFEFKK (KF8K) (F: phenylalanine; E: glutamic acid; K: lysine). First, Dox-loaded hydrogels were characterized to ensure that the incorporation of the drug did not significantly affect the hydrogel properties. Subsequently, Dox diffusion out of the hydrogels was investigated using UV absorbance. The amount of drug retained in F8/FE composite hydrogels was found to be directly proportional to the amount of charge carried by the peptide fibers. When cation−π interactions were used, the position and number of end-lysine were found to play a key role in the retention of Dox. In this case, the amount of Dox retained in F8/KF8K composite hydrogels was linked to the amount of end-lysine introduced, and an end-lysine/Dox interaction stoichiometry of 3/1 was obtained. For pure FE and KF8K hydrogels, the maximum amount of Dox retained was also found to be related to the overall concentration of the hydrogels and, therefore, to the overall fiber surface area available for interaction with the drug. For 14 mM hydrogel, ∼170–200 μM Dox could be retained after 24 h. This set of peptides also showed a broad range of susceptibilities to enzymatic degradation opening the prospect of being able to control also the rate of degradation of these hydrogels. Finally, the Dox released from the hydrogel was shown to be active and affect 3T3 mouse fibroblasts viability in vitro. Our study clearly shows the potential of this peptide design as a platform for the formulation of injectable or sprayable hydrogels for controlled drug delivery

Nation States, Cities, and People: Alternative Ways to Measure Globalization

In the last decade, attempts to measure globalization have multiplied, and they have led to the devising of diverse globalisation indexes. Besides other important similarities, the main feature shared by the most notable of these indexes is the fact that they use the same unit of analysis: the nation-state. This is a paradoxical situation, if one considers that one of the most distinctive characteristics of globalization is that its dynamics extend beyond the state. Gives this premise, the aim of the article is, on the one hand, to justify in any case the use of instruments that seek to measure globalization on the basis of states, and, on the other, to propose alternative approaches to such measurement. The paper\u2019s underlying assumption is that different approaches to the measurement of globalization are not mutually exclusive. Rather, such a plurality of perspectives is opportune given the complexity and multidimensionality of the concept of globalization

RNA extraction from self-assembling peptide hydrogels to allow qPCR analysis of encapsulated cells

Self-assembling peptide hydrogels offer a novel 3-dimensional platform for many applications in cell culture and tissue engineering but are not compatible with current methods of RNA isolation; owing to interactions between RNA and the biomaterial. This study investigates the use of two techniques based on two different basic extraction principles: solution-based extraction and direct solid-state binding of RNA respectively, to extract RNA from cells encapsulated in four β-sheet forming self-assembling peptide hydrogels with varying net positive charge. RNA-peptide fibril interactions, rather than RNA-peptide molecular complexing, were found to interfere with the extraction process resulting in low yields. A column-based approach relying on RNA-specific binding was shown to be more suited to extracting RNA with higher purity from these peptide hydrogels owing to its reliance on strong specific RNA binding interactions which compete directly with RNA-peptide fibril interactions. In order to reduce the amount of fibrils present and improve RNA yields a broad spectrum enzyme solution—pronase—was used to partially digest the hydrogels before RNA extraction. This pre-treatment was shown to significantly increase the yield of RNA extracted, allowing downstream RT-qPCR to be performed