Development of functionalized poly(lactide) films with chitosan via SI-SARA ATRP as scaffolds for neuronal cell growth.

Polylactic acid (PLA), a polymer derived from renewable resources, is gaining increasing attention in the development of biomedical devices due to its cost-effectiveness, low immunogenicity, and biodegradability. However, its inherent hydrophobicity remains a problem, leading to poor cell adhesion features. On this basis, the aim of this work was to develop a method for functionalizing the surface of PLA films with a biopolymer, chitosan (CH), which was proved to be a material with intrinsic cell adhesive properties, but whose mechanical properties are insufficient to be used alone. The combination of the two polymers, PLA as a bulk scaffold and CH as a coating, could be a promising combination to develop a scaffold for cell growth. The modification of PLA films involved several steps: aminolysis followed by bromination to graft amino and then bromide groups, poly(glycidyl methacrylate) (PGMA) grafting by surface-initiated supplemental activator and reducing agent atom transfer radical polymerization (SI-SARA ATRP) and finally the CH grafting. To prove the effective adhesive properties, conjugated and non-conjugated films were tested in vitro as substrates for neuronal cell growth using differentiated neurons from human induced pluripotent stem cells. The results demonstrated enhanced cell growth in the presence of CH.

Electrophysiological and morphological modulation of neuronal-glial network by breast cancer and nontumorigenic mammary cell conditioned medium.

Breast cancer is a significant global health concern, with the overexpression of human epidermal growth factor receptor 2 (HER2/ERBB2) being a driver oncogene in 20%-30% of cases. Indeed, HER2/ERBB2 plays a crucial role in regulating cell growth, differentiation, and survival via a complex signaling network. Overexpression of HER2/ERBB2 is associated with more aggressive behavior and increased risk of brain metastases, which remains a significant clinical challenge for treatment. Recent research has highlighted the role of breast cancer secretomes in promoting tumor progression, including excessive proliferation, immune invasion, and resistance to anti-cancer therapy, and their potential as cancer biomarkers. In this study, we investigated the impact of ERBB2+ breast cancer SKBR-3 cell line compared with MCF10-A mammary non-tumorigenic cell conditioned medium on the electrophysiological activity and morphology of neural networks derived from neurons differentiated from human induced pluripotent stem cells. Our findings provide evidence of active modulation of neuronal-glial networks by SKBR-3 and MCF10-A conditioned medium. These results provide insights into the complex interactions between breast cancer cells and the surrounding microenvironment. Further research is necessary to identify the specific factors within breast cancer conditioned medium that mediate these effects and to develop targeted therapies that disrupt this interaction.

Long-termin vitroculture of 3D brain tissue model based on chitosan thermogel.

Methods for studying brain function and disease heavily rely onin vivoanimal models,ex-vivotissue slices, and 2D cell culture platforms. These methods all have limitations that significantly impact the clinical translatability of results. Consequently, models able to better recapitulate some aspects ofin vivohuman brain are needed as additional preclinical tools. In this context, 3D hydrogel-basedin vitromodels of the brain are considered promising tools. To create a 3D brain-on-a-chip model, a hydrogel capable of sustaining neuronal maturation over extended culture periods is required. Among biopolymeric hydrogels, chitosan-ß-glycerophosphate (CHITO-ß-GP) thermogels have demonstrated their versatility and applicability in the biomedical field over the years. In this study, we investigated the ability of this thermogel to encapsulate neuronal cells and support the functional maturation of a 3D neuronal network in long-term cultures. To the best of our knowledge, we demonstrated for the first time that CHITO-ß-GP thermogel possesses optimal characteristics for promoting neuronal growth and the development of an electrophysiologically functional neuronal network derived from both primary rat neurons and neurons differentiated from human induced pluripotent stem cells (h-iPSCs) co-cultured with astrocytes. Specifically, two different formulations were firstly characterized by rheological, mechanical and injectability tests. Primary nervous cells and neurons differentiated from h-iPSCs were embedded into the two thermogel formulations. The 3D cultures were then deeply characterized by immunocytochemistry, confocal microscopy, and electrophysiological recordings, employing both 2D and 3D micro-electrode arrays. The thermogels supported the long-term culture of neuronal networks for up to 100 d. In conclusion, CHITO-ß-GP thermogels exhibit excellent mechanical properties, stability over time under culture conditions, and bioactivity toward nervous cells. Therefore, they are excellent candidates as artificial extracellular matrices in brain-on-a-chip models, with applications in neurodegenerative disease modeling, drug screening, and neurotoxicity evaluation.

Feeding and Eating Disorders in Bariatric Surgery: A Retrospective Study.

INTRODUCTION: Obese subjects undergoing bariatric surgery often display medical and psychiatric comorbidities, influencing post-operative course and long-term prognosis. Candidates for bariatric surgery are evaluated through a multidisciplinary assessment in the pre-operative phase, including a psychiatric visit. The psychiatric examination aims to screen psychiatric comorbidities, including feeding and eating disorders (FEDs). Indeed, there is evidence of the association between obesity and several psychiatric disorders, such as FEDs, but also anxiety disorders, mood disorders, psychotic disorders, neurodevelopment disorders and personality disorders, particularly B and C cluster personalities. This study aims to evaluate the presence of psychiatric comorbidities among a population of candidates for bariatric surgery, and to underline the clinical correlates of FEDs diagnosis at the pre-operative assessment. SUBJECTS AND METHODS: Patients were recruited at the outpatient service of the Section of Psychiatry, Clinical Psychology and Rehabilitation of the General Hospital/University of Perugia. Psychiatric comorbidities were investigated by a psychiatric interview and hetero-administered scales for the evaluation of DSM-5 psychiatric syndromes (Structured Interview for DSM-5 Disorders - clinical version - SCID-5-CV), psychopathological and personality characteristics (Minnesota Multiphasic Personality Inventory - MMPI-2 and Structured Clinical Interview for DSM-5-Personality Disorders - SCID-5-PD) and specific scales for the evaluation of FEDs (Binge Eating Scale - BES, Obesity Questionnaire - OQ, Bulimia Test-Revised - BULIT-R and Body Shape Questionnaire - BSQ). After performing descriptive statistics, we performed bivariate analyses to assess significant differences between subjects with and without FEDs diagnosis (p˂0.05). RESULTS: The sample was composed of 160 subjects (70.6% F versus 29.4% M). The average BMI was 42.90 ±6.258 and 86.8% of subjects had a Class 3 Obesity (BMI ≥40). 41.3% of patients received a psychiatric diagnosis and, specifically, a diagnosis of FEDs was highlighted in 28.7% cases. Individuals with FEDs more frequently had a family history of obesity and FEDs. As for psychopathological characteristics, altered scores on the BES and on the BULIT-R were more frequent in the group with psychiatric disorders excluding FEDs. CONCLUSIONS: Patients evaluated in bariatric surgery pre-operative assessment often display FEDs. Patients with FEDs more frequently suffer from other psychiatric disorders, showing the need for specific support pathways in this group of patients.

Coercion and Compulsory Treatment in Anorexia Nervosa: a Systematic Review on Legal and Ethical Issues.

BACKGROUND: The aim of this systematic review is to critically summarize current literature concerning ethical and legal issues related compulsory treatment (CT) in patients with anorexia nervosa (AN). SUBJECTS AND METHODS: Relevant articles were identified following the PRISMA guidelines after performing title/abstract screening and full text screening. We built the search string using the following terms: "coercion", "compulsory/involuntary treatment", "eating disorders", "anorexia nervosa", "mental capacity", "ethical/legal issues". Research was conducted on original articles published from any time until June 2023. RESULTS: Out of 302 articles retrieved, seven were included for the analysis, including five studies on mental health practitioners, and two on hospital records. The results show that mental health practitioners a) favor the use of CT, but the support is weaker in AN vs other psychiatric conditions (i.e., schizophrenia or depression); b) support of mental capacity is controversial and some variability was found between different categories of psychiatrists; in particular, both ED-treating and CT experienced mental health practitioners support higher use of CT and lack of capacity of AN patients vs. general psychiatrists; c) use of CT is more supported in the early vs. chronic AN, when chances of success are lower. The analysis of hospital records identified 1) comorbidities, previous admissions and current health risk as CT predictors in 96 Australian patients; 2) family conflicts association with longer hospitalizations in 70 UK patients. CONCLUSION: CT is usually intended for patients with AN at the onset of disease, mainly to prevent risk of death and self-injury. However, there is some variability in the attitude to perform CT among psychiatrists working in different setting, also related to the concept of mental capacity. There are also cross-national variabilities regarding CT. We can conclude that forcing patients to treatment is a conceivable option, but the balance between protection respect for patient's autonomy should be evaluated on individual bases.

3D Bioprinting as a Powerful Technique for Recreating the Tumor Microenvironment.

In vitro three-dimensional models aim to reduce and replace animal testing and establish new tools for oncology research and the development and testing of new anticancer therapies. Among the various techniques to produce more complex and realistic cancer models is bioprinting, which allows the realization of spatially controlled hydrogel-based scaffolds, easily incorporating different types of cells in order to recreate the crosstalk between cancer and stromal components. Bioprinting exhibits other advantages, such as the production of large constructs, the repeatability and high resolution of the process, as well as the possibility of vascularization of the models through different approaches. Moreover, bioprinting allows the incorporation of multiple biomaterials and the creation of gradient structures to mimic the heterogeneity of the tumor microenvironment. The aim of this review is to report the main strategies and biomaterials used in cancer bioprinting. Moreover, the review discusses several bioprinted models of the most diffused and/or malignant tumors, highlighting the importance of this technique in establishing reliable biomimetic tissues aimed at improving disease biology understanding and high-throughput drug screening.

Human-Derived Cortical Neurospheroids Coupled to Passive, High-Density and 3D MEAs: A Valid Platform for Functional Tests.

With the advent of human-induced pluripotent stem cells (hiPSCs) and differentiation protocols, methods to create in-vitro human-derived neuronal networks have been proposed. Although monolayer cultures represent a valid model, adding three-dimensionality (3D) would make them more representative of an in-vivo environment. Thus, human-derived 3D structures are becoming increasingly used for in-vitro disease modeling. Achieving control over the final cell composition and investigating the exhibited electrophysiological activity is still a challenge. Thence, methodologies to create 3D structures with controlled cellular density and composition and platforms capable of measuring and characterizing the functional aspects of these samples are needed. Here, we propose a method to rapidly generate neurospheroids of human origin with control over cell composition that can be used for functional investigations. We show a characterization of the electrophysiological activity exhibited by the neurospheroids by using micro-electrode arrays (MEAs) with different types (i.e., passive, C-MOS, and 3D) and number of electrodes. Neurospheroids grown in free culture and transferred on MEAs exhibited functional activity that can be chemically and electrically modulated. Our results indicate that this model holds great potential for an in-depth study of signal transmission to drug screening and disease modeling and offers a platform for in-vitro functional testing.

A micropatterned thermoplasmonic substrate for neuromodulation of in vitro neuronal networks.

Understanding how the spatial organization of a neural network affects its activity represents a leading issue in neuroscience. Thanks to their accessibility and easy handling, in vitro studies remain an essential tool to investigate the relationship between the structure and function of a neuronal network. Among all the patterning techniques, ink-jet printing acquired great interest thanks to its direct-write approach, which allows the patterned substrate realization without mold, leading to a considerable saving of both cost and time. However, the inks commonly used give the possibility to control only the structure of a neuronal network, leaving aside the functional aspect. In this work, we synthesize a photosensitive ink combining the rheological and bioadhesive properties of chitosan with the plasmonic properties of gold nanorods, obtaining an ink able to control both the spatial organization of a two-dimensional neuronal network and its activity through photothermal effect. After the ink characterization, we demonstrate that it is possible to print, with high precision, different geometries on a microelectrode array. In this way, it is possible obtaining a patterned device to control the structure of a neuronal network, to record its activity and to modulate it via photothermal effect. Finally, to our knowledge, we report the first evidence of photothermal inhibition of human neurons activity. STATEMENT OF SIGNIFICANCE: Patterned cell cultures remain the most efficient and simple tool for linking structural and functional studies, especially in the neuronal field. Ink-jet printing is the technique with which it is possible to realize patterned structures in the fastest, simple, versatile and low-cost way. However, the inks currently used permit the control only of the neuronal network structure but do not allow the control-modulation of the network activity. In this study, we realize and characterize a photosensitive bioink with which it is possible to drive both the structure and the activity of a neuronal network. Moreover, we report the first evidence of activity inhibition by the photothermal effect on human neurons as far as we know.

Enzymes Encapsulated within Alginate Hydrogels: Bioelectrocatalysis and Electrochemiluminescence Applications.

A simple procedure to incorporate enzymes (horseradish peroxidase, HRP, and lactate oxidase, LOx) within alginate hydrogels is reported with electrochemiluminescence (ECL) used to detect the enzymatic reactions with the corresponding substrates. First, HRP and LOx were successfully immobilized into CaCO3 microspheres, followed by the electrostatic layer-by-layer deposition of a nanoshell onto the microspheres, and finally by their dispersion into alginate solution. The as-prepared dispersion was drop cast onto the glassy carbon electrodes and cross-linked by the external and internal gelation methods using Ca2+ cations. The enzymes encapsulated within the alginate hydrogels were characterized using cyclic voltammetry and kinetic studies performed using ECL. The results showed that the enzymatic activity was significantly maintained as a result of the immobilization, with values of the apparent Michaelis-Menten constants estimated as 7.71 ± 0.62 and 8.41 ± 0.43 µM, for HRP and LOx, respectively. The proposed biosensors showed good stability and repeatability with an estimated limit of detection of 5.38 ± 0.05 and 0.50 ± 0.03 µM for hydrogen peroxide and lactic acid, respectively. The as-prepared enzymes encapsulated within the alginate hydrogels showed good stability up to 28 days from their preparation. The sensitivity and selectivity of the enzymes encapsulated within the alginate hydrogels were tested in real matrices (HRP, hydrogen peroxide, in contact lens solution; LOx, lactic acid in artificial sweat) showing the sensitivity of the ECL detection methods for the detection of hydrogen peroxide and lactic acid in real samples.

On the way back from 3D to 2D: Chitosan promotes adhesion and development of neuronal networks onto culture supports.

Most in vitro functional and morphological studies for developing nervous system have been performed using traditional monolayer cultures onto supports modified by extracellular matrix components or synthetic biopolymers. These biomolecules act as adhesion factors essential for neuronal growth and differentiation. In this study, the use of chitosan as adhesion factor was investigated. Primary rat neurons and neurons differentiated from human induced pluripotent stem cells were cultured onto chitosan and standard adhesion factors modified supports. The initiation, elongation and branching of neuritic processes, synaptogenesis and electrophysiological behavior were studied. The biopolymers affected neurites outgrowth in a time dependent manner; in particular, chitosan promoted neuronal polarity in both cell cultures. These results indicate chitosan as a valid adhesion factor alternative to the standard ones, with the advantage that it can be used both in 2D and 3D cultures, acting as a bridge between these in vitro models.

A facile approach for the development of high mechanical strength 3D neuronal network scaffold based on chitosan and graphite nanoplatelets.

In this work, novel composite microparticles based on chitosan (CHI) and graphite nanoplatelets (GNP) were developed as 3D scaffolds for neuronal cells. The aim is to improve the scaffold strength while maintaining its ability to sustain cell adhesion and differentiation. An air-assisted jetting technique followed by physical crosslinking is employed to obtain CHI/GNP microparticles. Optical and Field Emission Scanning Electron Microscopy micrographs showed a uniform distribution of GNP within the CHI porous matrix. The presence of GNP turned out to improve the strength of the microparticles while conferring good electrical conductivity and ameliorating their stability in aqueous environment. The morphological and immunocytochemical characterization, combined with a preliminary electrophysiological analysis, evidenced the effectiveness of the developed composite microparticles as a scaffold for neuron growth. These scaffolds could be employed for the development of advanced 3D neuronal in vitro models for networks dynamics analysis and drug screening.

Lipoperoxide Nanoemulsion as Adjuvant in Cisplatin Cancer Therapy: In Vitro Study on Human Colon Adenocarcinoma DLD-1 Cells.

Cisplatin is a first-choice chemotherapeutic agent used to treat solid tumors even though the onset of multi-drug resistance and the time-dose side-effects impair its mono-therapeutic application. Therefore, new drug-delivery approaches, based on nanomedicine strategies, are needed to enhance its therapeutic potential in favor of a dose-reduction of cisplatin. Polyunsaturated fatty acids and their metabolism-derived intermediates, as well as lipid peroxidation end-products, are used as adjuvants to improve the effectiveness of chemotherapy. Lipid hydroperoxides, derived from the oxidation of edible oils, can contribute to cell death, generating breakdown products (e.g., reactive aldehydes). In this regard, the aim of this present study was to evaluate an invitro combinatory strategy between a lecithin-based nanoemulsion system of K600, a patented mixture of peroxidated oil and peroxidated cholesterol, and cisplatin on DLD1 human adenocarcinoma cells. Our findings showed that nanoemulsions, acting in synergy with cisplatin, improve cisplatin bioactivity, in terms of enhancing its anti-cancer activity, towards DLD1 cells. Indeed, this combination approach, whilst maintaining cisplatin at low concentrations, induces a significant reduction in DLD1 cell viability, an increase in pro-apoptotic markers, and genotoxic damage. Therefore, K600 nanoemulsions as an efficient targeted delivery system of cisplatin allow for the reduction in the chemotherapeutic agent doses.

Dextran/poly-L-arginine multi-layered CaCO3-based nanosystem for vascular drug delivery.

The development of heterogeneous drug delivery systems leads to innovative strategies for targeted therapy of common pathologies, such as cancer, immunological and neurological disorders. Nowadays, it is possible to choose among a great variety of nanoparticles on the basis of the needs they have to satisfy. However, a candidate for the treatment of cardiovascular pathologies is still missing. In this context, a targeted therapy implies the conceptualization of nanoparticles that take active part in the treatment of vascular pathologies. The aim of this work was to provide a method to produce multi-layered calcium carbonate (CaCO3) nanoparticles encapsulating a model protein, bovine serum albumin, with model antibodies on their surface. CaCO3 nanoparticles were produced by the combination of complex coacervation and mineralization and were engineered using layer-by-layer technique with a polysaccharide, dextran sulfate, and a homo-poly-amino acid, poly-L-arginine. Morphology, biocompatibility, cellular uptake, influence on cell expression of the inflammatory marker matrix metalloproteinase-9, and hemocompatibility of the nanoparticles were studied. The presence of the dextran/poly-L-arginine layers did not negatively affect the nanoparticle overall characteristics and they did not trigger proinflammatory response in vitro. Taking together all the obtained results, we consider the proposed CaCO3 nanoparticles as a promising tool in cardiovascular field.

Biodegradable Defined Shaped Printed Polymer Microcapsules for Drug Delivery.

This work describes the preparation and characterization of printed biodegradable polymer (polylactic acid) capsules made in two different shapes: pyramid and rectangular capsules about 1 and 11 µm in size. Obtained core-shell capsules are described in terms of their morphology, loading efficiency, cargo release profile, cell cytotoxicity, and cell uptake. Both types of capsules showed monodisperse size and shape distribution and were found to provide sufficient stability to encapsulate small water-soluble molecules and to retain them for several days and ability for intracellular delivery. Capsules of 1 µm size can be internalized by HeLa cells without causing any toxicity effect. Printed capsules show unique characteristics compared with other drug delivery systems such as a wide range of possible cargoes, triggered release mechanism, and highly controllable shape and size.

Assembly of chitosan-graphite oxide nanoplatelets core shell microparticles for advanced 3D scaffolds supporting neuronal networks growth.

This manuscript reports the development of functional 3D scaffolds based on chitosan (CHI) and graphite oxide nanoplatelets (GO) for neuronal network growth. To this aim, CHI microparticles, produced by alkaline gelation method, were coated with GO exploiting a simple template-assisted assembly based on the electrostatic attraction in an aqueous medium. The optimal deposition conditions were evaluated by optical microscopy and studied by quartz crystal microbalance. FE-SEM observations highlight the formation of a core-shell structure where the porous chitosan core is completely wrapped by a uniform GO layer. This outer shell protects the inner chitosan from enzymatic degradation thus potentially extending the scaffold viability for in vivo applications. The presence of hydrophilic oxygen-containing functionalities on the outermost layer of GO and its inner conductive graphitic core maintained the bioactivity of the scaffold and promoted neuronal cell adhesion and growth. The proposed approach to modify the surface of CHI microparticles makes it possible for the design of 3D scaffolds for advanced neuronal tissue engineering applications.

On an effective approach to improve the properties and the drug release of chitosan-based microparticles.

The work investigated the possibility to develop an easy scalable treatment capable of modifying only the surface of chitosan-based materials, limiting the degradation of the bulk and the burst release of a drug, without compromising the properties of the polymeric matrix. To this aim, microparticles of CHI were superficially coated with poly-(styrene-co-maleic anhydride) (PSMA), taking advantage of the potential reactivity of chitosan amino groups and maleic functionalities of PSMA. The specific reactions/interactions occurring between the two polymers were studied by IR measurements, while FE-SEM analysis evidenced the modification of the morphology of the particles contacted with PSMA. Contact angle measurements demonstrated the change of wettability in the modified systems and TGA analysis allowed to estimate the amount of the deposited PSMA. The above treatment turned out to improve the particle stability both in an acidic environment and in an enzymatic system. The release properties of the treated and of the untreated particles, over a period of 10 h, were tested using, as model drug, the protein Bovine Serum Albumin (BSA). Finally, the cytocompatibility of the developed composite microparticles was assessed on MCF-7 human breast cancer cells, which measurements demonstrated the non-toxicity of the treatment.

Alginate microbeads with internal microvoids for the sustained release of drugs.

The process of Ca2+ mediated gelation of alginate and the fabrication of nanoengineered polyelectrolyte capsules were combined for the preparation of alginate microbeads characterized by the presence of well-defined drug loaded microvoids in their volume. The obtained engineered alginate microbeads are described in terms of their morphology, loading efficiency and release characteristics. It was found that the generation of microvoids in the volume of alginate microbeads could be a promising approach for the creation of microstructured and biocompatible hydrogels, prospectively having highly tunable properties in terms of loading and releasing characteristics. In particular, it was found that the developed system was able to limit drug leakage during the gelation process and to control the initial burst release of small hydrophilic drug molecules, such as doxorubicin hydrochloride. Finally, the cytocompatibility of the developed microhydrogels was assessed on MCF-7 human breast cancer cells as well as their ability to sustain the release of the model drug during time.

Sustained delivery of growth factors with high loading efficiency in a layer by layer assembly.

Layer by layer (LBL) assembly has garnered considerable interest due to its ability to generate multifunctional films with high tunability and versatility in terms of substrates and polyelectrolytes, allowing the option to use complex devices and drugs. Polyelectrolytes, such as growth factors (GFs), are essential, but costly, delicate, biological molecules that have been used in various tissue regeneration applications. For this reason, the controlled drug delivery of efficiently loaded GFs via LBL assembly (GF-LBL) can contribute to the establishment of cost-effective biologically triggered biomedical applications. We have developed an LBL method to load GFs (specifically, transforming growth factor beta 1, platelet-derived growth factor ßß, and insulin growth factor 1), with up to 90% efficiency approximately, by gas plasma surface activation and tuning the pH to increase the ionic strength of polyelectrolytes. Poly(styrenesulfonate) (PSS) and poly(ethyleneimine) (PEI) have been used to provide the initial necessary charge for multilayer build-up. Heparin and dextran sulphate have been investigated as counter polyelectrolytes to enhance the activity of GFs by protecting their ligands, where heparin resulted in the highest achievable loading efficiency for all GFs. Oxygen gas plasma and acidic pH levels also resulted in a significant increase in GF loading efficiency. The three GFs were released by diffusion and erosion in a controlled manner over lengthy time scales and the bioactivity was maintained for up to 14 days. When tested as implants in vitro, GF-LBL constructs increased fibroblast proliferation, influenced cell morphology and migration, and enhanced myofibroblast differentiation, indicating that the biological functionalities of the GFs were preserved. In conclusion, this developed LBL assembly method can provide a simple drug delivery system, which may yield more effective applications for tissue regeneration as well as biomedical sciences at large.

Disassembling the complexity of mucus barriers to develop a fast screening tool for early drug discovery.

Mucus is a natural barrier with a protective role that hinders drug diffusion, representing a steric and interactive barrier to overcome for an effective drug delivery to target sites. In diseases like cystic fibrosis (CF), pulmonary mucus exhibits altered features, which hamper clearance mechanisms and drug diffusion, ultimately leading to lung failure. Effectively modelling the passage through mucus still represents an unmet challenge. An airway CF mucus model is herein proposed to disassemble the complexity of the mucus barrier following a modular approach. A hydrogel, mainly composed of mucin in an alginate (Alg) network, is proposed to specifically model the chemical-physical properties of CF mucus. The steric retention of pathological mucus was reproduced by targeting its mesh size (approximately 50 nm) and viscoelastic properties. The interactive barrier was reproduced by a composition inspired from the CF mucus. Optimized mucus models, composed of 3 mg ml-1 Alg and 25 mg ml-1 mucin, exhibited a G' increasing from ∼21.2 to 55.2 Pa and a G'' ranging from ∼5.26 to 28.8 Pa in the frequency range of 0.1 to 20 Hz. Drug diffusion was tested using three model drugs. The proposed mucus model was able to discriminate between the mucin-drug interaction and the steric barrier of a mucus layer with respect to the parallel artificial membrane permeability (PAMPA) that models the phospholipidic cell membrane, the state-of-the-art screening tool for passive drug diffusion. The mucus model can be proposed as an in vitro tool for early drug discovery, representing a step forward to model the mucus layer. Additionally, the proposed methodology allows to easily include other molecules present within mucus, as relevant proteins, lipids and DNA.

Multicompartment Hydrogels for the Local Delivery of Chemotherapic Drugs.

Over 85% of human cancers are solid tumors. The effectiveness of anticancer therapy in solid tumors depends on adequate delivery of the therapeutic agent to tumor cells. Inadequate delivery would result in residual tumor cells, which in turn would lead to regrowth of tumors and possibly development of resistant cells. The most prominent option, for now, is the local delivery of chemotherapic drugs into the cavity resection of the tumor. However, the burst release of massive concentrations of the drugs usually boosts the side effects of chemotherapy. Aiming to block the burst release a new drug delivery system (DDS) for the local delivery of Doxorubicin (DOX) was designed and tested, combining different materials and techniques. Following a bottom-up approach, porous spherical calcium carbonate (CaCO3) microspheres, with high loading properties, were loaded with DOX and Layer by Layer (LbL) assembled by biocompatible and biodegradable polyelectrolytes, dextran sodium sulfate (DSS) and polyarginine (PARG). Then, a protocol for the fabrication of alginate (Alg) hydrogels associated with LbL coated drug loaded CaCO3 microspheres were developed by combining internal and external gelation. Therefore, injectable multicompartment hydrogels (MCH) for the local and sustained delivery of chemotherapeutic drugs, with the ability to block the burst release, were developed and characterized.