Novel biomaterials for innovative therapies in the severe wounds treatment

Treatment of non-healing wounds represents hitherto a severe dilemma for the healthcare worldwide because of wound failure to recover. The physiological wound healing is in fact a critical process requiring lack of both bacterial contamination and persistent inflammatory events in the damaged site. Despite a broad range of both antimicrobial and anti-inflammatory agents is commercially available, a successful tackling of bacterial infections and chronic inflammation is particularly challenging due to the increase of microbial resistance and remarkable side effects caused by an abuse of drugs. To this end, the development of innovative biomaterials used in combination with alternative agents is very challenging. The goals for the present thesis were to fabricate and characterize in terms of physical, chemical and biological properties, nanoengineered biomaterials to be used in the treatment of severe wounds. The potential use of two polysaccharides, namely chitosan and hyaluronan, and of their derivatives has been investigated. In the Chapter I is described an innovative method for the production of tridimensional hydrogels based on chitosan and on the cross-linker tripolyphosphate (TPP). The possibility to obtain hydrogels with chitosans with different acetylation degree (Fa) and molecular weight (Mw) was tackled. Resulting hydrogels were studied in terms of mechanical properties. Finally, soft-pliable and biocompatible membranes were obtained by freeze-drying. Further analyses are accounted in the Chapter II aiming at deeply investigating on hydrogel-forming process. More in detail, the different affinity of cross-linkers TPP and pyrophosphate (PPi) towards chitosan was explored in diluted solutions. The mechanical behavior of resulting hydrogels was further investigated whereas the polymer distribution within matrices has been assessed by both qualitative and quantitative methods. In the Chapter III the preparation of soft pliable chitosan-based membranes prepared from hydrogels containing antimicrobial silver nanoparticles (AgNPs) stabilized by a lactose-modified chitosan (chitlac) is tackled. A thorough investigation on bactericidal properties of the material revealed the synergistic activity of chitosan and AgNPs to reduce the growth of different bacteria strains and to break apart mature biofilms. Finally, biocompatibility assays on keratinocytes and fibroblasts did not prove any harmful effect on mammalian cells. The anti-inflammatory behavior of the short chain fatty acid butyrate is discussed in the first part of Chapter IV. Such feature was proved to be time- and dose-dependent. To extend on time and to modulate the biological activity of butyrate, chitosan/hyaluronan-based nanoparticles (complexes) were developed. These carriers showed the ability to encapsulate butyrate as payload, an intrinsic scavenging activity, the ability to quickly interact with neutrophils, muco-adhesive properties and lack of cytotoxicity. In the Chapter V it has been reported the biological investigation of a complex between hyaluronan-lipoate and silver ions (named SHLS12). Biological studies showed the ability of SHLS12 to exert a straightforward bactericidal activity against different bacterial strains grown both in sessile and planktonic state. The lack of toxicity was proved towards mammalian cells. By considering its ability to preserve antibacterial properties when exposed to serum proteins, this complex may be considered as a promising biomaterial for the treatment of non-healing wounds

Silver-containing antimicrobial membrane based on chitosan-TPP hydrogel for the treatment of wounds

Treatment of non-healing wounds represents hitherto a severe dilemma because of their failure to heal caused by repeated tissue insults, bacteria contamination and altered physiological condition. This leads to face huge costs for the healthcare worldwide. To this end, the development of innovative biomaterials capable of preventing bacterial infection, of draining exudates and of favoring wound healing is very challenging. In this study, we exploit a novel technique based on the slow diffusion of tripolyphosphate for the preparation of macroscopic chitosan hydrogels to obtain soft pliable membranes which include antimicrobial silver nanoparticles (AgNPs) stabilized by a lactose-modified chitosan (Chitlac). UV-Vis and TEM analyses demonstrated the time stability and the uniform distribution of AgNPs in the gelling mixture, while swelling studies indicated the hydrophilic behavior of membrane. A thorough investigation on bactericidal properties of the material pointed out the synergistic activity of chitosan and AgNPs to reduce the growth of S. aureus, E. coli, S. epidermidis, P. aeruginosa strains and to break apart mature biofilms. Finally, biocompatibility assays on keratinocytes and fibroblasts did not prove any harmful effects on the viability of cells. This novel technique enables the production of bioactive membranes with great potential for the treatment of non-healing wounds

Galectin-1 protein modified gold (III)-PEGylated complex-nanoparticles: Proof of concept of alternative probe in colorimetric glucose detection

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Insights into Mechanical Behavior and Biological Properties of Chia Seed Mucilage Hydrogels

In this contribution we report insights on the rheological properties of chia (Salvia hispanica) seed mucilage hydrogels. Specifically, we studied the influence of temperature and polymer concentration on the viscoelastic properties of resulting networks. Creep experiments performed in steady-state conditions allowed calculating Newtonian viscosities for chia hydrogels at different polymer concentrations, pointing at inter-chain interactions as the main responsible for the different behavior toward network slipping under constant stress. The combination of oscillatory frequency and stress sweep tests highlighted a moderate effect of temperature in influencing hydrogel mechanics. The latter results prompted us to investigate potential biological functions for this set of biomaterials. Lactate Dehydrogenase assay proved lack of cytotoxicity of chia suspensions toward Human Mesenchymal Stem Cells from adipose tissue here used as cell model. Differentiation experiments were finally undertaken to verify the influence of chia samples on osteo-induction triggered by chemical differentiation factors. Alkaline Phosphatase enzyme activity assay and Alizarin red staining demonstrated that chia mucilage did not alter in vitro stem cell differentiation. Collectively, this set of experiments revealed an almost inert role associated with chia suspensions, indicating a possible application of chia-based networks as scaffold models to study osteogenesis in vitro

Controlled Quenching of Agarose Defines Hydrogels with Tunable Structural, Bulk Mechanical, Surface Nanomechanical, and Cell Response in 2D Cultures

: The scaffolding of agarose hydrogel networks depends critically on the rate of cooling (quenching) after heating. Efforts are made to understand the kinetics and evolution of biopolymer self-assembly upon cooling, but information is lacking on whether quenching might affect the final hydrogel structure and performance. Here, a material strategy for the fine modulation of quenching that involves temperature-curing steps of agarose is reported. Combining microscopy techniques, standard and advanced macro/nanomechanical tools, it is revealed that agarose accumulates on the surface when the curing temperature is set at 121 °C. The inhomogeneity can be mostly recovered when it is reduced to 42 °C. This has a drastic effect on the stiffness of the surface, but not on the viscoelasticity, roughness, and wettability. When hydrogels are strained at small/large deformations, the curing temperature has no effect on the viscoelastic response of the hydrogel bulk but does play a role in the onset of the non-linear region. Cells cultured on these hydrogels exhibit surface stiffness-sensing that affects cell adhesion, spreading, F-actin fiber tension, and assembly of vinculin-rich focal adhesions. Collectively, the results indicate that the temperature curing of agarose is an efficient strategy to produce networks with tunable mechanics and is suitable for mechanobiology studies

A silver complex of hyaluronan-lipoate (SHLS12): Synthesis, characterization and biological properties

In this study we present a novel silver complex of hyaluronan-lipoate (SHLS12) in a gel-state form. NMR analysis, conductometry and elemental analysis demonstrated stable non-covalent interactions between silver ions and the polysaccharide-lipoate backbone, whereas rheological investigations confirmed its gel-like physical-chemical behavior. Biological studies showed the ability of SHLS12 to exert a straightforward activity against different bacterial strains grown in sessile/planktonic state. The biocompatibility was also proved toward two eukaryotic cell lines. By considering both its ability to preserve antibacterial properties when exposed to the serum protein BSA and its low susceptibility to be degraded by hyaluronidase enzyme, this novel complex may be considered as a promising biomaterial for future in vivo applications

The Potential Role of the Early Maladaptive Schema in Behavioral Addictions Among Late Adolescents and Young Adults

Background: Behavioral addiction (BA) is a recent concept in psychiatry. Few studies have investigated the relationship between BA and early maladaptive schemas (EMSs). EMS is the core of Schema Therapy (ST). According to the ST model, psychiatric disorders result from the development of EMSs in response to unmet emotional needs in childhood. Bach et al. (2018) grouped the 18 EMSs into four domains: (1) disconnection and rejection; (2) impaired autonomy and performance; (3) excessive responsibility and standards; and (4) impaired limits. This study aims to assess the possible association of the most frequent BAs with EMSs in a large group of late adolescents and young adults and to evaluate their self-perceived quality of life (QoL). Methods: A battery of psychological tests assessing food addiction (FA), gambling disorder (GD), internet addiction (IA), and QoL was administered to 1,075 late adolescents and young adults (N = 637; 59.3% women). A forward-stepwise logistic regression model was run to identify which variables were associated with BAs. Results: Food addiction was more frequent among women and GD among men, while IA was equally distributed. Regarding the EMSs, participants with FA or IA showed significantly higher scores on all four-schema domains, whereas those with GD exhibited higher scores on impaired autonomy and performance and impaired limits. Besides, average scores of all domains increased with the association of two or more comorbid BAs. Self-perceived QoL was lower for participants with FA and IA, but not for those with GD; the presence of comorbid BAs was associated with lower Physical Component Summary (PCS) and Mental Component Summary (MCS) scores. Finally, specific EMS domains and demographic variables were associated with each BA. Conclusion: Late adolescents and young adults with FA or IA have a lower perception of their mental and physical health. The most striking result is that FA appears to be associated with the disconnection and rejection schema domain, IA with all the schema domains (except for impaired autonomy and performance), and GD with impaired autonomy and performance schema domain. In conclusion, our findings suggest that EMS should be systematically assessed during psychotherapy of patients with BAs

Nucleation, reorganization and disassembly of an active network from lactose-modified chitosan mimicking biological matrices

Developing synthetic materials able to mimic micro- and macrorheological properties of natural networks opens up to novel applications and concepts in materials science. The present contribution describes an active network based on a semi-synthetic polymer, a lactitol-bearing chitosan derivative (Chitlac), and a transient inorganic cross-linker, boric acid. Due to the many and diverse anchoring points for boric acid on the flanking groups of Chitlac, the cross-links constantly break and reform in a highly dynamic fashion. The consequence is a network with unusual non-equilibrium and mechanical properties closely resembling the rheological behavior of natural three-dimensional arrangements and of cytoskeleton. Concepts like network nucleation, reorganization and disassembly are declined in terms of amount of the cross-linker, which acts as a putative motor for remodeling of the network upon application of energy. The out-of-equilibrium and non-linear behavior render the semi-synthetic system of great interest for tissue engineering and for developing in-vitro mimics of natural active matrices

Benzene and lipid asset

Background: In relation to the medico-social and medico-legal aspects of urban pollution we studied the effects of benzene present in urban pollution on outdoor workers exposed to physical, chemical, and psychosocial stressors. The purpose of this study is to evaluate the possible correlation between the levels of benzene and its urinary metabolites in the blood (Trans muconic acid and S-phenylmecapturic acid) and the parameters of the lipid structure: Total cholesterol, High Density Lipoprotein (HDL), Low Density Lipoprotein (LDL), triglycerides and blood sugar. Materials and methods: From an initial group 1,500 we selected a group of 199 subjects. A blood sample was taken for each worker to assess blood benzene levels and urinalysis to determine the levels of trans, trans-muconic acid and S-phenyl mercapturic acid. We compared the mean and standard deviation of the following lipid parameters: Total Cholesterol, HDL, LDL, Triglycerides and glycemia with benzene and urinary metabolites; we excluded the workers with confounding factors and performed the Pearson’s correlation between lipid parameters and urinary metabolites in the total sample and also among age, seniority, sex and BMI; multiple linear regression was performed for the evaluation of the main confounding factors. Results: We did not find a statistically significant alteration between the values of the lipid structure between the two groups of workers and the parameters of benzene. Triglycerides and HDL are statistically significantly influenced by sex (p=0.001) and (p=0.00) and BMI (p=0.00) and (p=0.001) as well as total cholesterol is influenced in a statistically significant way from age (p=0.003) and blood glucose from BMI (p=0.002) A statistically significant difference was found among the averages of phenylmercapturic S acid values of traffic policeman and police drivers (p<0.05), where higher values were among drivers. Conclusions: The results suggest that occupational exposure to levels of benzene, present in urban pollution, would appear not to influence the values of the lipid parameters in traffic policeman

Violent behaviors and Klinefelter syndrome: Two forensic cases from the past to the future

Klinefelter Syndrome (KS) (XXY) is the most common sex-chromosome aberration among men. The cognitive phenotype includes language learning problems, mental retardation, and psychiatric disorders. Patients can show criminal personality and psychosocial problems. The most common offences reported are sexual abuse, arson, burglary, homicide, drug-related crimes. KS very often goes under-diagnosed. The aim of our study is to verify the hypothesis of correlation between chromosomal abnormalities and criminal behaviors through the analysis of a forensic case of uxoricide/suicide. We report the case of an old man, found dead in his cottage with a gun in the right hand. Judicial inspection demonstrated suicidal single gunshot injuries. Data analysis highlighted a personal story of uxoricide. Autopsy investigation showed the typical KS phenotype. The post-mortem clinical diagnosis was confirmed through the genetic analysis of the karyotype. The retrospective analysis of literature with this case showed a possible correlation between KS and psychiatric traits, with criminal personality and sexual disorders