Effect of Hyaluronan Molecular Weight on the Stability and Biofunctionality of Microfibers Assembled by Interfacial Polyelectrolyte Complexation.

Nervous system disorders are characterized by a progressive loss of function and structure of neurons that ultimately leads to a decline in cognitive and motor functions. In this study, we used interfacial polyelectrolyte complexation (IPC) to produce fibers for neural tissue regeneration. IPC is a processing method that allows spinning of sensitive biopolymers.

Cholesterol Conjugated Elastin-like Recombinamers: Molecular Dynamics Simulations, Conformational Changes, and Bioactivity.

Current models for elastin-like recombinamer (ELR) design struggle to predict the effects of nonprotein fused materials on polypeptide conformation and temperature-responsive properties. To address this shortage, we investigated the novel functionalization of ELRs with cholesterol (CTA). We employed GROMACS computational molecular dynamic simulations complemented with experimental evidence to validate the predictions.

Antibacterial properties of photo-crosslinked chitosan/methacrylated hyaluronic acid nanoparticles loaded with bacitracin.

The current treatments for wounds often fail to induce adequate healing, leaving wounds vulnerable to persistent infections and development of drug-resistant microbial biofilms. New natural-derived nanoparticles were studied to impair bacteria colonization and hinder the formation of biofilms in wounds. The nanoparticles were fabricated through polyelectrolyte complexation of chitosan (CS, polycation) and hyaluronic acid (HA, polyanion).

Multifunctional calcium-based nanocarriers for synergistic treatment of triple-negative breast cancer.

Targeted breast cancer therapies hold the potential to improve the efficiency of drug delivery to the pathology site without impacting the viability and function of healthy cells. Herein, we developed multifunctional nanocarriers that target simultaneously several downstream signaling processes in triple negative breast cancer cells. The system comprises pH sensitive CaCO nanoparticles (NPs) as carriers of the anticancer drug doxorubicin (DOX).

A Label-Free Multitechnique Approach to Characterize the Interaction of Bioactive Compounds with Biomimetic Interfaces.

Extensive research has been conducted on biomimetic interfaces mimicking the complex and diverse microenvironment of cell membranes to gain insights into bioactive compound interactions and membrane biophysics modulation. The present study proposes an innovative approach that combines five prospective label-free methodologies (derivative spectroscopy, synchrotron small- and wide-angle X-Ray scattering, attenuated total reflection-Fourier-transform infrared spectroscopy, quartz-crystal microbalance with dissipation, and surface plasmon resonance) to showcase their synergistic capabilities and complementarity in investigating drug-membrane interactions. This multitechnique approach combines the real-time monitoring of the adsorption process under continuous flow conditions with the steady-state perspective of this process.

Layer-by-layer coated calcium carbonate nanoparticles for targeting breast cancer cells.

Breast cancer is resistant to conventional treatments due to the specific tumour microenvironment, the associated acidic pH and the overexpression of receptors that enhance cells tumorigenicity. Herein, we optimized the synthesis of acidic resorbable calcium carbonate (CaCO) nanoparticles and the encapsulation of a low molecular weight model molecule (Rhodamine). The addition of ethylene glycol during the synthetic process resulted in a particle size decrease: we obtained homogeneous CaCO particles with an average size of 564 nm.

Exploiting Polyelectrolyte Complexation for the Development of Adhesive and Bioactive Membranes Envisaging Guided Tissue Regeneration.

Mussels secrete protein-based byssal threads to tether to rocks, ships, and other organisms underwater. The secreted marine mussel adhesive proteins (MAPs) contain the peculiar amino acid L-3,4-dihydroxyphenylalanine (DOPA), whose catechol group content contributes greatly to their outstanding adhesive properties. Inspired by such mussel bioadhesion, we demonstrate that catechol-modified polysaccharides can be used to obtain adhesive membranes using the compaction of polyelectrolyte complexes (CoPEC) method.

Liposomes embedded in layer by layer constructs as simplistic extracellular vesicles transfer model.

Extracellular vesicles (EVs) are particles originating from the exfoliation of the cellular membrane. They are involved in cell-to-cell and cell-to-matrix signaling, exchange of bioactive molecules, tumorigenesis and metastasis, among others. To mitigate the limited understanding of EVs transfer phenomena, we developed a simplistic model that mimics EVs and their interactions with cells and the extracellular matrix.

Unenhanced computed tomography (CT) utility for triage at the emergency department during COVID-19 pandemic.

Background: Unenhanced chest computed tomography (CT) can assist in the diagnosis and classification of coronavirus disease 2019 (COVID-19), complementing to the reverse-transcription polymerase chain reaction (RT-PCR) tests; the performance of which has yet to be validated in emergency department (ED) setting. The study sought to evaluate the diagnostic performance of chest CT in the diagnosis and management of COVID-19 in ED.

Methods: This retrospective single-center study included 155 patients in ED who underwent both RT-PCR and chest CT for suspected COVID-19 from March 1st to April 1st, 2020.

Bioinspired baroplastic glycosaminoglycan sealants for soft tissues.

We describe biomimetic adhesives inspired by the marine glues fabricated by the sandcastle worm. The formation of stable polyelectrolyte complexes between poly-L-lysine (PLL) and glycosaminoglycans (GAGs) with different sulfation degree - heparin (HEP), chondroitin sulfate (CS) and hyaluronic acid (HA) - is optimized by zeta-potential titrations. These PLL/GAG complexes are transformed into compact polyelectrolyte complexes (coPECs) with controlled water contents and densities via baroplastic processing.

Tuning the Stiffness of Surfaces by Assembling Genetically Engineered Polypeptides with Tailored Amino Acid Sequence.

We introduce elastin-like recombinamers (ELRs) as polypeptides with precise amino acid positioning to generate polypeptide coatings with tunable rigidity. Two ELRs are used: V84-ELR, a hydrophobic monoblock, and EI-ELR, an amphiphilic diblock. Both were modified with the amine-reactive tetrakis (hydroxymethyl) phosphonium chloride compound.

Development of Inhalable Superparamagnetic Iron Oxide Nanoparticles (SPIONs) in Microparticulate System for Antituberculosis Drug Delivery.

Tuberculosis (TB) is an infectious disease which affects millions of people worldwide. Inhalable polymeric dry powders are promising alternatives as anti-TB drug carriers to the alveoli milieu and infected macrophages, with potential to significantly improve the therapeutics efficiency. Here, the development of a magnetically responsive microparticulate system for pulmonary delivery of an anti-TB drug candidate (P3) is reported.

Multilayered Films Produced by Layer-by-Layer Assembly of Chitosan and Alginate as a Potential Platform for the Formation of Human Adipose-Derived Stem Cell aggregates.

The construction of multilayered films with tunable properties could offer new routes to produce biomaterials as a platform for 3D cell cultivation. In this study, multilayered films produced with five bilayers of chitosan and alginate (CHT/ALG) were built using water-soluble modified mesyl and tosyl⁻CHT via layer-by-layer (LbL) self-assembly. NMR results demonstrated the presences of mesyl (2.

The potential of cashew gum functionalization as building blocks for layer-by-layer films.

Cashew gum (CG), an exudate polysaccharide from Anacardium occidentale trees, was carboxymethylated (CGCm) and oxidized (CGO). These derivatives were characterized by FTIR and zeta potential measurements confirming the success of carboxymethylation and oxidation reactions. Nanostructured multilayered films were then produced through layer-by-layer (LbL) assembly in conjugation with chitosan via electrostatic interactions or Schiff bases covalent bonds.

Chitosan/Chondroitin Sulfate Membranes Produced by Polyelectrolyte Complexation for Cartilage Engineering.

Membranes made of chitosan (CHT) and chondroitin sulfate (CS) are herein presented using a polyelectrolyte complexation sedimentation/evaporation method. The membranes present high roughness and heterogeneous morphology induced by salt crystals. Exposing the membranes to different salt concentrations induces saloplastic behavior, as shown by an increasing water absorption and decreasing stiffness while exposed to increasing concentrations of salt.

Enzymatic Degradation of Polysaccharide-Based Layer-by-Layer Structures.

The lack of knowledge on the degradation of layer-by-layer structures is one of the causes hindering its translation to preclinical assays. The enzymatic degradation of chitosan/hyaluronic acid films in the form of ultrathin films, freestanding membranes, and microcapsules was studied resorting to hyaluronidase. The reduction of the thickness of ultrathin films was dependent on the hyaluronidase concentration, leading to thickness and topography variations.

Marine Origin Polysaccharides in Drug Delivery Systems.

Oceans are a vast source of natural substances. In them, we find various compounds with wide biotechnological and biomedical applicabilities. The exploitation of the sea as a renewable source of biocompounds can have a positive impact on the development of new systems and devices for biomedical applications.

pH Responsiveness of Multilayered Films and Membranes Made of Polysaccharides.

We investigated the pH-dependent properties of multilayered films made of chitosan (CHI) and alginate (ALG) and focused on their postassembly response to different pH environments using a quartz crystal microbalance with dissipation monitoring (QCM-D), swelling studies, ζ potential measurements, and dynamic mechanical analysis (DMA). In an acidic environment, the multilayers presented lower dissipation values and, consequently, higher moduli when compared with the values obtained for the pH used during the assembly (5.5).

Drug nano-reservoirs synthesized using layer-by-layer technologies.

The pharmaceutical industry has been able to tackle the emergence of new microorganisms and diseases by synthesizing new specialized drugs to counter them. Their administration must ensure that a drug is effectively encapsulated and protected until it reaches its target, and that it is released in a controlled way. Herein, the potential of layer-by-layer (LbL) structures to act as drug reservoirs is presented with an emphasis to "nano"-devices of various geometries, from planar coatings to fibers and capsules.

Cellular uptake of multilayered capsules produced with natural and genetically engineered biomimetic macromolecules.

Multilayered microcapsules of chitosan and biomimetic elastin-like recombinamers (ELRs) were prepared envisaging the intracellular delivery of active agents. Two ELRs containing either a bioactive RGD sequence or a scrambled non-functional RDG were used to construct two types of functionalized polymeric microcapsules, both of spherical shape ∼4μm in diameter. Cell viability studies with human mesenchymal stem cells (hMSCs) were performed using microcapsule/cell ratios between 5:1 and 100:1.

Polyelectrolyte multilayered assemblies in biomedical technologies.

Layer-by-layer (LbL) was first introduced as a surface modification technique based on the sequential spontaneous adsorption of at least two distinct materials onto planar substrates. In the last two decades, this technique has been expanded to the coating of more convoluted geometries with high levels of tailored functionalization or with structural purposes. In this review, the potential uses of LbL films in biomedical engineering based mainly on the assembly of polyelectrolytes are reviewed.

Multifunctional compartmentalized capsules with a hierarchical organization from the nano to the macro scales.

Inspired by the cells' structure, we present compartmentalized capsules with temperature and magnetic-based responsiveness and hierarchical organization ranging from the nano- to the visible scales. Liquefied alginate macroscopic beads coated with a layer-by-layer (LbL) chitosan/alginate shell served as containers both for model fluorophores and microcapsules, which in their turn encapsulated either another fluorophore or magnetic nanoparticles (MNPs). The microcapsules were coated with a temperature-responsive chitosan/elastin-like recombinamer (ELR) nanostructured shell.

Layer-by-layer film growth using polysaccharides and recombinant polypeptides: a combinatorial approach.

Nanostructured films consisting of polysaccharides and elastin-like recombinamers (ELRs) are fabricated in a layer-by-layer manner. A quartz-crystal microbalance with dissipation monitoring (QCM-D) is used to follow the buildup of hybrid films containing one polysaccharide (chitosan or alginate) and one of several ELRs that differ in terms of amino acid content, length, and biofunctionality in situ at pH 4.0 and pH 5.

Adhesive nanostructured multilayer films using a bacterial exopolysaccharide for biomedical applications.

Medical adhesives and sealants often require that long-term adhesiveness is achieved. In this work, nanostructured coatings consisting of chitosan and the adhesive bacterial exopolysaccharide levan are fabricated using layer-by-layer (LbL) assembly. Taking advantage of the electrostatic self-assembly mechanism of LbL, the charges of both chitosan and a phosphonate-derivatized levan (Ph-levan) are measured and the feasibility of constructing hybrid films is monitored and confirmed using a quartz crystal microbalance with dissipation monitoring (QCM-D).

Nanostructured and thermoresponsive recombinant biopolymer-based microcapsules for the delivery of active molecules.

Unlabelled: Multilayer capsules conceived at the nano- and microscales are receiving increasing interest due to their potential role as carriers of biomolecules for drug delivery and tissue engineering. Herein we report the construction of microcapsules by the sequential adsorption of chitosan and a biomimetic elastin-like recombinamer into nanostructured layers on inorganic microparticle templates. The release profile of bovine serum albumin, which was studied at 25 and 37 °C, shows higher retention and Fickian diffusion at physiological temperature.