Polyetheretherketone Double Functionalization with Bioactive Peptides Improves Human Osteoblast Response.

In recent years, the demand for orthopedic implants has surged due to increased life expectancy, necessitating the need for materials that better mimic the biomechanical properties of human bone. Traditional metal implants, despite their mechanical superiority and biocompatibility, often face challenges such as mismatched elastic modulus and ion release, leading to complications and implant failures. Polyetheretherketone (PEEK), a semi-crystalline polymer with an aromatic backbone, presents a promising alternative due to its adjustable elastic modulus and compatibility with bone tissue.

Evaluation of the Biocompatibility of Poly(benzimidazobenzophenanthroline)(BBL) Polymer Films with Living Cells.

The integration of organic electronic materials with biological systems to monitor, interface with, and regulate physiological processes is a key area in the field of bioelectronics. Central to this advancement is the development of cell-chip coupling, where materials engineering plays a critical role in enhancing biointerfacing capabilities. Conductive polymers have proven particularly useful in cell interfacing applications due to their favorable biophysical and chemical properties.

Development of alginate film filled with halloysite-carbon dots for active food packaging.

The development of functional bionanocomposites for active food packaging is of current interest to replace non-biodegradable plastic coatings. In the present work, we report the synthesis of an alginate-based nanocomposite filled with modified halloysite nanotubes (HNTs) to develop coatings with improved barrier properties for food packaging. Firstly, HNTs were chemically modified by the introduction of carbon dots units (CDs) onto their external surface (HNTs-CDs) obtaining a nanomaterial where CDs are uniformly present onto the tubes as verified by morphological investigations, with good UV absorption and antioxidant properties.

Building Surfaces with Controlled Site-Density of Anchored Human Serum Albumin.

Stable and uniform layers of protein molecules at the surface are important to build passive devices as well as active constructs for smart biointerfaces for a large number of biomedical applications. In this context, a strategy to build-up surfaces able to anchor protein molecules on specific and controlled surface sites has been developed. Human serum albumin (HSA) has been chosen as a model protein due to its important antithrombogenic properties and its features in cell response highly valuable for in vivo devices.

Strategies for the Covalent Anchoring of a BMP-2-Mimetic Peptide to PEEK Surface for Bone Tissue Engineering.

Researchers in the field of tissue engineering are always searching for new scaffolds for bone repair. Polyetheretherketone (PEEK) is a chemically inert polymer that is insoluble in conventional solvents. PEEK's great potential in tissue engineering applications arises from its ability to not induce adverse reactions when in contact with biological tissues and its mechanical properties, which are similar to those of human bone.

Adsorption of the rhNGF Protein on Polypropylene with Different Grades of Copolymerization.

The surface properties of drug containers should reduce the adsorption of the drug and avoid packaging surface/drug interactions, especially in the case of biologically-derived products. Here, we developed a multi-technique approach that combined Differential Scanning Calorimetry (DSC), Atomic Force Microscopy (AFM), Contact Angle (CA), Quartz Crystal Microbalance with Dissipation monitoring (QCM-D), and X-ray Photoemission Spectroscopy (XPS) to investigate the interactions of rhNGF on different pharma grade polymeric materials. Polypropylene (PP)/polyethylene (PE) copolymers and PP homopolymers, both as spin-coated films and injected molded samples, were evaluated for their degree of crystallinity and adsorption of protein.

Bioactive PEEK: Surface Enrichment of Vitronectin-Derived Adhesive Peptides.

Polyetheretherketone (PEEK) is a thermoplastic polymer that has been recently employed for bone tissue engineering as a result of its biocompatibility and mechanical properties being comparable to human bone. PEEK, however, is a bio-inert material and, when implanted, does not interact with the host tissues, resulting in poor integration. In this work, the surfaces of 3D-printed PEEK disks were functionalized with: (i) an adhesive peptide reproducing [351-359] h-Vitronectin sequence (HVP) and (ii) HVP retro-inverted dimer (D2HVP), that combines the bioactivity of the native sequence (HVP) with the stability toward proteolytic degradation.

Cytostatic Effects of Polyethyleneimine Surfaces on the Mesenchymal Stromal Cell Cycle.

Polyelectrolytes assembled layer-by-layer (PEMs) are commonly used as functional coatings to build-up biological interfaces, particularly suitable as compatible layers for the interaction with a biological medium, providing suitable conditions to promote or prevent cell seeding while maintaining the phenotype. The proper assessment of the biocompatibility of PEMs and the elucidation of the related mechanisms are therefore of paramount importance. In this study, we report in detail the effect of two different PEM endings, polystyrene sulfonate (PSS) and polyethylenimine (PEI), respectively, on the cell adhesion, growth, and viability of human bone mesenchymal stromal cells (MSCs).

Electrospun Chitosan Functionalized with C12, C14 or C16 Tails for Blood-Contacting Medical Devices.

Medical applications stimulate the need for materials with broad potential. Chitosan, the partially deacetylated derivative of chitin, offers many interesting characteristics, such as biocompatibility and chemical derivatization possibility. In the present study, porous scaffolds composed of electrospun interwoven nanometric fibers are produced using chitosan or chitosan functionalized with aliphatic chains of twelve, fourteen or sixteen methylene groups.

Bioactivated Oxidized Polyvinyl Alcohol towards Next-Generation Nerve Conduits Development.

The limitations and difficulties that nerve autografts create in normal nerve function recovery after injury is driving research towards using smart materials for next generation nerve conduits (NCs) setup. Here, the new polymer partially oxidized polyvinyl alcohol (OxPVA) was assayed to verify its future potential as a bioactivated platform for advanced/effective NCs. OxPVA-patterned scaffolds (obtained by a 3D-printed mold) with/without biochemical cues (peptide IKVAV covalently bound (OxPVA-IKVAV) or self-assembling peptide EAK (sequence: AEAEAKAKAEAEAKAK), mechanically incorporated (OxPVA+EAK) versus non-bioactivated scaffold (peptide-free OxPVA (PF-OxPVA) supports, OxPVA without IKVAV and OxPVA without EAK control scaffolds) were compared for their biological effect on neuronal SH-SY5Y cells.

Porphyrin-Based Supramolecular Flags in the Thermal Gradients' Wind: What Breaks the Symmetry, How and Why.

The Spontaneous Symmetry Breaking (SSB) phenomenon is a natural event in which a system changes its symmetric state, apparently reasonless, in an asymmetrical one. Nevertheless, this occurrence could be hiding unknown inductive forces. An intriguing investigation pathway uses supramolecular aggregates of suitable achiral porphyrins, useful to mimic the natural light-harvesting systems (as chlorophyll).

From nanoaggregates to mesoscale ribbons: the multistep self-organization of amphiphilic peptides.

This paper reports atomic force microscopy results and molecular dynamics simulations of the striking differences of long-term self-organization structures of negatively charged (AcA)KD (double tail) and AcAD (single tail) peptides, respectively, forming micrometer-long, linearly ordered ribbon-like structures and nanometer-sized, unstructured, round-shaped aggregates. The subsequent formation steps of the long-range nanoribbons, experimentally observed only for the "double tail" (AcA)KD peptide, are analyzed in detail, showing that the initial "primary" unstructured round-shaped aggregates progressively evolve into longer nanofilaments and into micrometer-long, network-forming nanoribbon moieties. In particular, the long-range self-organization of the "double tail" peptides appears to be closely related to electrostatically driven diffusional motions of the primary aggregates and nanofilaments.

EAK Hydrogels Cross-Linked by Disulfide Bonds: Cys Number and Position Are Matched to Performances.

Hydrogels produced by self-assembling peptides are intrinsically biocompatible and thus appropriate for many biomedical purposes. Their application field may be even made wider by reducing the softness and improving the hydrogel mechanical properties through cross-linking treatments. To this aim, modifications of EAK16-II sequence by including Cys residues in its sequence were here investigated in order to obtain hydrogels cross-linkable through a disulfide bridge.

Reactive nanomessengers for artificial chemical communication.

Artificial chemical communication is an emerging field of study driven by the need of exchanging information in delicate environments where standard procedures based on electromagnetic waves cannot be used. A non-synchronized artificial chemical communication system, based on a new modulation technique, namely reaction shift keying (RSK), is presented. The RSK implies that the quenchers are injected into the transmitter, the chemical messenger reacts and a chemically modified messenger travels towards the receiver.

3D Synthetic Peptide-based Architectures for the Engineering of the Enteric Nervous System.

Damage of enteric neurons and partial or total loss of selective neuronal populations are reported in intestinal disorders including inflammatory bowel diseases and necrotizing enterocolitis. To develop three-dimensional scaffolds for enteric neurons we propose the decoration of ionic-complementary self-assembling peptide (SAP) hydrogels, namely EAK or EAbuK, with bioactive motives. Our results showed the ability of EAK in supporting neuronal cell attachment and neurite development.

Molecular Sponge: pH-Driven Reversible Squeezing of Stimuli-Sensitive Peptide Monolayers.

The cyclic change of structure, thickness, and density, with pH switching from acidic (pH = 3) to basic (pH = 11) condition, has been revealed for chemisorbed monolayers of the peptide Lipo-Aib-Lys-Leu-Aib-Lys-Lys-Leu-Aib-Lys-Ile-Lol, a trichogin GA IV-analogue carrying Lys residues instead of Gly ones at positions 2, 5, 6, and 9, while a homologous peptide not containing Lys residues does not show any response to pH changes. Experimental and theoretical results, obtained by means of quartz crystal microbalance with dissipation monitoring, surface plasmon resonance, nanoplasmonic sensing technique, Fourier transform infrared-reflection attenuated spectroscopy and dynamic force spectroscopy, and molecular dynamics simulations provide detailed information on the overall monolayer structure changes with pH, including the analysis of the intra- and interchain peptide dynamics, the structure of the peptide layer/water/solid interface, as well as the position and role of solvation and nonsolvation water. The observed stimuli-responsive behavior of L1 peptide monolayers is accounted in terms of the occurrence of a pH-induced wetting/dewetting process, due to the pH-induced switching of the hydrophilic character of charged lysine groups to hydrophobic one of the same uncharged groups, along the peptide chain.

Reactive messengers for digital molecular communication with variable transmitter-receiver distance.

Molecular communication exploits functional molecular systems travelling along fluid media to deliver messages encoded as concentration pulses, e.g. molecular bits.

Driving Coordination Polymer Monolayer Formation by Competitive Reactions at the Air/Water Interface.

We have developed a novel approach enabling us to follow and facilitate the formation of two-dimensional coordination polymer monolayers directly at the air/water interface without the need of complex instrumentation. The method is based on the use of a surface active ligand that, when spread at the air/water interface, progressively undergoes hydrolysis with consequent gradual decrease in surface pressure. Notably, if the aqueous subphase contains metal ions capable of coordinating the ligand, coordination competes with hydrolysis, resulting in a lower surface pressure decrease.

Orienting proteins by nanostructured surfaces: evidence of a curvature-driven geometrical resonance.

Experimental and theoretical reports have shown that nanostructured surfaces have a dramatic effect on the amount of protein adsorbed and the conformational state and, in turn, on the performances of the related devices in tissue engineering strategies. Here we report an innovative method to prepare silica-based nanostructured surfaces with a reproducible, well-defined local curvature, consisting of ordered hexagonally packed arrays of curved hemispheres, from nanoparticles of different diameters (respectively 147 nm, 235 nm and 403 nm). The nanostructured surfaces have been made chemically homogeneous by partially embedding silica nanoparticles in poly(hydroxymethylsiloxane) films, further modified by means of UV-O3 treatments.

Design of Decorated Self-Assembling Peptide Hydrogels as Architecture for Mesenchymal Stem Cells.

Hydrogels from self-assembling ionic complementary peptides have been receiving a lot of interest from the scientific community as mimetic of the extracellular matrix that can offer three-dimensional supports for cell growth or can become vehicles for the delivery of stem cells, drugs or bioactive proteins. In order to develop a 3D "architecture" for mesenchymal stem cells, we propose the introduction in the hydrogel of conjugates obtained by chemoselective ligation between a ionic-complementary self-assembling peptide (called EAK) and three different bioactive molecules: an adhesive sequence with 4 Glycine-Arginine-Glycine-Aspartic Acid-Serine-Proline (GRGDSP) motifs per chain, an adhesive peptide mapped on h-Vitronectin and the growth factor Insulin-like Growth Factor-1 (IGF-1). The mesenchymal stem cell adhesion assays showed a significant increase in adhesion and proliferation for the hydrogels decorated with each of the synthesized conjugates; moreover, such functionalized 3D hydrogels support cell spreading and elongation, validating the use of this class of self-assembly peptides-based material as very promising 3D model scaffolds for cell cultures, at variance of the less realistic 2D ones.

Fluorescent Quantum Dots Make Feasible Long-Range Transmission of Molecular Bits.

The modeling and realization of an effective communication platform for long-range information transfer is reported. Messages are encrypted in molecular bits by concentration pulses of fluorescent carbon quantum dots having self-quenching emission that dynamically depends on the concentration pulses. Messages are transferred along longer paths when received and decoded by means of dynamical emission response with respect to the ones encoded by absorbance scaling linearly with messenger concentration.

Specific and selective probes for Staphylococcus aureus from phage-displayed random peptide libraries.

Staphylococcus aureus is a major human pathogen causing health care-associated and community-associated infections. Early diagnosis is essential to prevent disease progression and to reduce complications that can be serious. In this study, we selected, from a 9-mer phage peptide library, a phage clone displaying peptide capable of specific binding to S.

Electrospun Scaffolds for Osteoblast Cells: Peptide-Induced Concentration-Dependent Improvements of Polycaprolactone.

The design of hybrid poly-ε-caprolactone (PCL)-self-assembling peptides (SAPs) matrices represents a simple method for the surface functionalization of synthetic scaffolds, which is essential for cell compatibility. This study investigates the influence of increasing concentrations (2.5%, 5%, 10% and 15% w/w SAP compared to PCL) of three different SAPs on the physico-chemical/mechanical and biological properties of PCL fibers.

Impact of selective fibronectin nanoconfinement on human dental pulp stem cells.

In this study, it was aimed to investigate the combinatory effect of biophysical and biochemical factors on human dental pulp stem cells' (hDPSCs) behavior. For this purpose, well-defined nanotopography of nanowells with two different pitch size of 109 nm and 341 nm were prepared on polyhydroxymethylsiloxane (PHMS) by using colloidal particles nanofabrication. The nanopatterned PHMS surfaces (PHMS/109 and PHMS/341) were subsequently used for fibronectin (Fn) adsorption.

Hyaluronan-based pericellular matrix: substrate electrostatic charges and early cell adhesion events.

Cells are surrounded by a hyaluronan-rich coat called 'pericellular matrix' (PCM), mainly constituted by hyaluronan, a long-chain linear polysaccharide which is secreted and resorbed by the cell, depending on its activity. Cell attachment to a surface is mediated by PCM before integrins and focal adhesions are involved. As hyaluronan is known to bear a negative charge at physiological pH, the relevance of its electrical properties in driving the early cell adhesion steps has been studied, exploring how PCM mediates cell adhesion to charged surfaces, such as polyelectrolyte multilayer (PEM) films.