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1.
Bioengineering (Basel) ; 11(2)2024 Feb 17.
Article in English | MEDLINE | ID: mdl-38391679

ABSTRACT

Bone defects are a significant health problem worldwide. Novel treatment approaches in the tissue engineering field rely on the use of biomaterial scaffolds to stimulate and guide the regeneration of damaged tissue that cannot repair or regrow spontaneously. This work aimed at developing and characterizing new piezoelectric scaffolds to provide electric bio-signals naturally present in bone and vascular tissues. Mixing and extrusion were used to obtain nanocomposites made of polyhydroxybutyrate (PHB) as a matrix and barium titanate (BaTiO3) nanoparticles as a filler, at BaTiO3/PHB compositions of 5/95, 10/90, 15/85 and 20/80 (w/w%). The morphological, thermal, mechanical and piezoelectric properties of the nanocomposites were studied. Scanning electron microscopy analysis showed good nanoparticle dispersion within the polymer matrix. Considerable increases in the Young's modulus, compressive strength and the piezoelectric coefficient d31 were observed with increasing BaTiO3 content, with d31 = 37 pm/V in 20/80 (w/w%) BaTiO3/PHB. 3D printing was used to produce porous cubic-shaped scaffolds using a 90° lay-down pattern, with pore size ranging in 0.60-0.77 mm and good mechanical stability. Biodegradation tests conducted for 8 weeks in saline solution at 37 °C showed low mass loss (∼4%) for 3D printed scaffolds. The results obtained in terms of piezoelectric, mechanical and chemical properties of the nanocomposite provide a new promising strategy for vascularized bone tissue engineering.

2.
Molecules ; 29(2)2024 Jan 22.
Article in English | MEDLINE | ID: mdl-38276612

ABSTRACT

Bacteriotherapy is emerging as a strategic and effective approach to treat infections by providing putatively harmless bacteria (i.e., probiotics) as antagonists to pathogens. Proper delivery of probiotics or their metabolites (i.e., post-biotics) can facilitate their availing of biomaterial encapsulation via innovative manufacturing technologies. This review paper aims to provide the most recent biomaterial-assisted strategies proposed to treat infections or dysbiosis using bacteriotherapy. We revised the encapsulation processes across multiscale biomaterial approaches, which could be ideal for targeting different tissues and suit diverse therapeutic opportunities. Hydrogels, and specifically polysaccharides, are the focus of this review, as they have been reported to better sustain the vitality of the live cells incorporated. Specifically, the approaches used for fabricating hydrogel-based devices with increasing dimensionality (D)-namely, 0D (i.e., particles), 1D (i.e., fibers), 2D (i.e., fiber meshes), and 3D (i.e., scaffolds)-endowed with probiotics, were detailed by describing their advantages and challenges, along with a future overlook in the field. Electrospinning, electrospray, and 3D bioprinting were investigated as new biofabrication methods for probiotic encapsulation within multidimensional matrices. Finally, examples of biomaterial-based systems for cell and possibly post-biotic release were reported.


Subject(s)
Bioprinting , Tissue Engineering , Tissue Engineering/methods , Bioprinting/methods , Biocompatible Materials , Printing, Three-Dimensional , Technology , Hydrogels/therapeutic use , Tissue Scaffolds
3.
Int J Mol Sci ; 24(11)2023 May 29.
Article in English | MEDLINE | ID: mdl-37298394

ABSTRACT

Three-dimensional scaffold-based culture has been increasingly gaining influence in oncology as a therapeutic strategy for tumors with a high relapse percentage. This study aims to evaluate electrospun poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA) scaffolds to create a 3D model of colorectal adenocarcinoma. Specifically, the physico-mechanical and morphological properties of PCL and PLA electrospun fiber meshes collected at different drum velocities, i.e., 500 rpm, 1000 rpm and 2500 rpm, were assessed. Fiber size, mesh porosity, pore size distribution, water contact angle and tensile mechanical properties were investigated. Caco-2 cells were cultured on the produced PCL and PLA scaffolds for 7 days, demonstrating good cell viability and metabolic activity in all the scaffolds. A cross-analysis of the cell-scaffold interactions with morphological, mechanical and surface characterizations of the different electrospun fiber meshes was carried out, showing an opposite trend of cell metabolic activity in PLA and PCL scaffolds regardless of the fiber alignment, which increased in PLA and decreased in PCL. The best samples for Caco-2 cell culture were PCL500 (randomly oriented fibers) and PLA2500 (aligned fibers). Caco-2 cells had the highest metabolic activity in these scaffolds, with Young's moduli in the range of 8.6-21.9 MPa. PCL500 showed Young's modulus and strain at break close to those of the large intestine. Advancements in 3D in vitro models of colorectal adenocarcinoma could move forward the development of therapies for this cancer.


Subject(s)
Adenocarcinoma , Colorectal Neoplasms , Humans , Tissue Engineering/methods , Caco-2 Cells , Neoplasm Recurrence, Local , Polyesters , Tissue Scaffolds
4.
Children (Basel) ; 10(6)2023 Jun 09.
Article in English | MEDLINE | ID: mdl-37371268

ABSTRACT

BACKGROUND: Patients with anorectal malformation (ARM) need long-term follow-up, in order to evaluate fecal continence; the main predictors of longer-term success are the type of ARM, associated anomalies and sacral integrity. Three-Dimensional High Resolution Anorectal Manometry (3D-HRAM) gives detailed information on pressure on the anal complex profile. Our objective was to analyze anal sphincter activity in ARM patients with 3D-HRAM establishing the correlation between manometric and clinical data. METHODS: Forty ARM patients were submitted to 3D-HRAM: manometric, anatomical and clinical scores were correlated with each other and with the bowel management response (BM). RESULTS: A positive correlation between all scores and types of ARM was found: in high ARM and in patients with spinal anomalies (regardless to ARM type) lower scores were reported and even after BM they did not achieve good continence. CONCLUSIONS: 3D-HRAM gives detailed data on the functional activity of the anal sphincter complex. Our study revealed a correlation between manometric parameters and clinical outcomes, confirming spinal malformations and ARM type as the most important prognostic risk factors for a bad outcome. Specific sphincteric defects can also be explored with manometry, allowing for tailored bowel management strategies.

5.
ACS Biomater Sci Eng ; 9(3): 1285-1295, 2023 03 13.
Article in English | MEDLINE | ID: mdl-36857509

ABSTRACT

Micro-prosthetics requires the fabrication of mechanically robust and personalized components with sub-millimetric feature accuracy. Three-dimensional (3D) printing technologies have had a major impact on manufacturing such miniaturized devices for biomedical applications; however, biocompatibility requirements greatly constrain the choice of usable materials. Hydroxyapatite (HA) and its composites have been widely employed to fabricate bone-like structures, especially at the macroscale. In this work, we investigate the rheology, printability, and prosthetic mechanical properties of HA and HA-silk protein composites, focusing on the roles of composition and water content. We correlate key linear and nonlinear shear rheological parameters to geometric outcomes of printing and explain how silk compensates for the inherent brittleness of printed HA components. By increasing ink ductility, the inclusion of silk improves the quality of printed items through two mechanisms: (1) reducing underextrusion by lowering the required elastic modulus and, (2) reducing slumping by increasing the ink yield stress proportional to the modulus. We demonstrate that the elastic modulus and compressive strength of parts fabricated from silk-HA inks are higher than those for rheologically comparable pure-HA inks. We construct a printing map to guide the manufacturing of HA-based inks with excellent final properties, especially for use in biomedical applications for which sub-millimetric features are required.


Subject(s)
Biocompatible Materials , Durapatite , Durapatite/chemistry , Silk , Elastic Modulus , Printing, Three-Dimensional
6.
J Funct Biomater ; 14(3)2023 Mar 04.
Article in English | MEDLINE | ID: mdl-36976069

ABSTRACT

Type-1 diabetes is one of the most prevalent metabolic disorders worldwide. It results in a significant lack of insulin production by the pancreas and the ensuing hyperglycemia, which needs to be regulated through a tailored administration of insulin throughout the day. Recent studies have shown great advancements in developing an implantable artificial pancreas. However, some improvements are still required, including the optimal biomaterials and technologies to produce the implantable insulin reservoir. Here, we discuss the employment of two types of cyclic olefin copolymers (Topas 5013L-10 and Topas 8007S-04) for an insulin reservoir fabrication. After a preliminary thermomechanical analysis, Topas 8007S-04 was selected as the best material to fabricate a 3D-printed insulin reservoir due to its higher strength and lower glass transition temperature (Tg). Fiber deposition modeling was used to manufacture a reservoir-like structure, which was employed to assess the ability of the material to prevent insulin aggregation. Although the surface texture presents a localized roughness, the ultraviolet analysis did not detect any significant insulin aggregation over a timeframe of 14 days. These interesting results make Topas 8007S-04 cyclic olefin copolymer a potential candidate biomaterial for fabricating structural components in an implantable artificial pancreas.

7.
Children (Basel) ; 9(12)2022 Dec 17.
Article in English | MEDLINE | ID: mdl-36553430

ABSTRACT

BACKGROUND: Dysphagia in neurologically impaired children is associated with feeding difficulties, malnutrition and aspiration pneumonia. Esophageal high-resolution manometry (HRM) has been used in the diagnosis of motility disorders affecting the swallowing process. The aim of this study was to analyze swallowing functions in NI children by using HRM in order to establish swallow parameters identifying inhalation risk. METHODS: Twenty-five NI children with cerebral palsy were submitted to esophageal HRM with UES analysis, comparing the results with non-NI children. The following parameters were evaluated: maximum pressure and duration of contraction of the velopharynx (VP) and tongue base (TB), and maximal, minimal, resting pressure and relaxation duration of the upper esophageal sphincter (UES). RESULTS: pVP max, pTB max, pUES max and resting pressure were lower, while p UES minimal was higher and relaxation duration was shorter in NI children vs. the control group. Predictive values of inhalation risk were evaluated. CONCLUSIONS: This study evaluates inhalation risk in NI children using HRM to study UES function. Our results confirm the alterations described in NI children: insufficient contraction and clearing force for bolus transmission through the pharynx and incomplete UES relaxation can predispose to pharyngeal residues and inhalation independently of swallowing because of lower values of UES resting.

8.
Pathogens ; 11(11)2022 Nov 07.
Article in English | MEDLINE | ID: mdl-36365057

ABSTRACT

Objectives: To describe a case of Shanghai fever disease and to analyze other published reports in non-Asiatic countries, defining clinical characteristics and highlighting that this is not only an Asian disease. Study design: A computerized search without language restriction was conducted using PubMed and Scopus; all references listed were hand-searched to identify any other relevant literature. An article was considered eligible for inclusion in the systematic review if it reported cases with Shanghai fever described in non-Asiatic countries. Our case was also included in the analysis. Results: Ten articles reporting 10 cases of Shanghai fever disease were considered. Fever, diarrhea and ecthyma gangrenosum were the most frequent symptoms observed. Blood was the most common site of isolation for Pseudomonas aeruginosa. Three patients underwent surgery due to necrotizing enteritis and intestinal perforation. Meningitis was documented in one case. None of the patients received antipseudomonal antibiotics within 24 h of admission. The outcome was good in nine cases; only one patient died due to multiple organ failure from Pseudomonas sepsis. No common primary immune deficiency was identified in these patients. Extremely young age (<1 year) was the only host factor predisposing to Shanghai fever. Conclusions: It is important to shed light on this disease in non-Asiatic countries and take into account that it can also affect healthy children. Pediatricians, therefore, should consider Shanghai fever among diagnoses in children with community-onset diarrhea, fever and skin lesions suggestive of ecthyma gangrenosum to start an appropriate treatment sooner and to reduce the mortality in these children.

9.
Biosensors (Basel) ; 12(10)2022 Oct 07.
Article in English | MEDLINE | ID: mdl-36290973

ABSTRACT

Acoustic signals are important markers to monitor physiological and pathological conditions, e.g., heart and respiratory sounds. The employment of traditional devices, such as stethoscopes, has been progressively superseded by new miniaturized devices, usually identified as microelectromechanical systems (MEMS). These tools are able to better detect the vibrational content of acoustic signals in order to provide a more reliable description of their features (e.g., amplitude, frequency bandwidth). Starting from the description of the structure and working principles of MEMS, we provide a review of their emerging applications in the healthcare field, discussing the advantages and limitations of each framework. Finally, we deliver a discussion on the lessons learned from the literature, and the open questions and challenges in the field that the scientific community must address in the near future.


Subject(s)
Acoustics , Micro-Electrical-Mechanical Systems , Monitoring, Physiologic , Delivery of Health Care
10.
Proc Natl Acad Sci U S A ; 119(40): e2209524119, 2022 10 04.
Article in English | MEDLINE | ID: mdl-36161946

ABSTRACT

Collagen is the most abundant structural protein in humans, providing crucial mechanical properties, including high strength and toughness, in tissues. Collagen-based biomaterials are, therefore, used for tissue repair and regeneration. Utilizing collagen effectively during materials processing ex vivo and subsequent function in vivo requires stability over wide temperature ranges to avoid denaturation and loss of structure, measured as melting temperature (Tm). Although significant research has been conducted on understanding how collagen primary amino acid sequences correspond to Tm values, a robust framework to facilitate the design of collagen sequences with specific Tm remains a challenge. Here, we develop a general model using a genetic algorithm within a deep learning framework to design collagen sequences with specific Tm values. We report 1,000 de novo collagen sequences, and we show that we can efficiently use this model to generate collagen sequences and verify their Tm values using both experimental and computational methods. We find that the model accurately predicts Tm values within a few degrees centigrade. Further, using this model, we conduct a high-throughput study to identify the most frequently occurring collagen triplets that can be directly incorporated into collagen. We further discovered that the number of hydrogen bonds within collagen calculated with molecular dynamics (MD) is directly correlated to the experimental measurement of triple-helical quality. Ultimately, we see this work as a critical step to helping researchers develop collagen sequences with specific Tm values for intended materials manufacturing methods and biomedical applications, realizing a mechanistic materials by design paradigm.


Subject(s)
Deep Learning , Amino Acid Sequence , Biocompatible Materials , Collagen/chemistry , Humans , Molecular Dynamics Simulation
11.
Sensors (Basel) ; 22(2)2022 Jan 17.
Article in English | MEDLINE | ID: mdl-35062658

ABSTRACT

The COVID-19 outbreak has increased the incidence of tracheal lesions in patients who underwent invasive mechanical ventilation. We measured the pressure exerted by the cuff on the walls of a test bench mimicking the laryngotracheal tract. The test bench was designed to acquire the pressure exerted by endotracheal tube cuffs inflated inside an artificial model of a human trachea. The experimental protocol consisted of measuring pressure values before and after applying a maneuver on two types of endotracheal tubes placed in two mock-ups resembling two different sized tracheal tracts. Increasing pressure values were used to inflate the cuff and the pressures were recorded in two different body positions. The recorded pressure increased proportionally to the input pressure. Moreover, the pressure values measured when using the non-armored (NA) tube were usually higher than those recorded when using the armored (A) tube. A periodic check of the cuff pressure upon changing the body position and/or when performing maneuvers on the tube appears to be necessary to prevent a pressure increase on the tracheal wall. In addition, in our model, the cuff of the A tube gave a more stable output pressure on the tracheal wall than that of the NA tube.


Subject(s)
COVID-19 , Trachea , Humans , Intensive Care Units , Intubation, Intratracheal , SARS-CoV-2
12.
Children (Basel) ; 8(12)2021 Dec 11.
Article in English | MEDLINE | ID: mdl-34943370

ABSTRACT

BACKGROUND: Transanal irrigation (TAI) is employed for children with fecal incontinence, but it can present several problems which require a study of their outcomes among different pathologies and without a tailored work up. The aim of our study was to evaluate the effectiveness of an advanced protocol in order to tailor TAI, prevent complications, and evaluate outcomes. METHODS: We included 70 patients (14 anorectal malformation, 12 Hirschsprung's disease, 24 neurological impairment, 20 functional incontinence) submitted to a comprehensive protocol with Peristeen®: fecal score, volumetric enema, rectal ultrasound, anorectal 3D manometry, and diary for testing and parameter adjustment. RESULTS: Among the patients, 62.9% needed adaptations to the parameters, mainly volume of irrigated water and number of puffs of balloon. These adaptations were positively correlated with pre-treatment manometric and enema data. In each group, the improvement of score was statistically significant in all cases (p 0.000); the main factor influencing the efficacy was the rate of sphincter anomalies. The ARM group had slower improvement than other groups, whereas functional patients had the best response. CONCLUSIONS: Our results showed that TAI should not be standardized for all patients, because each one has different peculiarities; evaluation of patients before TAI with rectal ultrasound, enema, and manometry allowed us to tailor the treatment, highlighting different outcomes among various pathologies, thus improving the efficacy.

13.
Children (Basel) ; 8(11)2021 Oct 23.
Article in English | MEDLINE | ID: mdl-34828669

ABSTRACT

Children with intellectual disability/neurodevelopmental delay (ID-ND) commonly ingest foreign bodies (FB) and often present complications due to peculiar aspects of their condition. The aim of this paper is to report the experience of two centers in the management of ID-ND patients after FB ingestion and to discuss a possible algorithm for clinical practice. We retrospectively evaluated data of patients managed for FB ingestion (period: 2017-2021), focusing on those with ID-ND, specifically demographics and baseline diagnosis, elements related to the event, symptoms, time to endoscopy, FB location, endoscopic details, and follow-up. A total of 457 patients were managed in the study period and 19 had ID-ND (mean age 9.8 ± 3.5 years, 15 males). A total of 16/19 (84.2%) were symptomatic and required an operative approach. Recurrent ingestions and multiple FB were found in 2 and 11 patients, respectively. Endoscopy (mean time 65.6 ± 41 min) was effective in 14 cases (73.6%) and 6 patients (31.6%) developed a complication. FB ingestion in ID-ND patients represents a challenging condition for the clinician and a potentially dangerous situation. It should be addressed specifically by a multidisciplinary team considering a tailored diagnostic and management protocol.

14.
Biomolecules ; 11(11)2021 11 20.
Article in English | MEDLINE | ID: mdl-34827729

ABSTRACT

The demand for bone substitutes is increasing in Western countries. Bone graft substitutes aim to provide reconstructive surgeons with off-the-shelf alternatives to the natural bone taken from humans or animal species. Under the tissue engineering paradigm, biomaterial scaffolds can be designed by incorporating bone stem cells to decrease the disadvantages of traditional tissue grafts. However, the effective clinical application of tissue-engineered bone is limited by insufficient neovascularization. As bone is a highly vascularized tissue, new strategies to promote both osteogenesis and vasculogenesis within the scaffolds need to be considered for a successful regeneration. It has been demonstrated that bone and blood vases are piezoelectric, namely, electric signals are locally produced upon mechanical stimulation of these tissues. The specific effects of electric charge generation on different cells are not fully understood, but a substantial amount of evidence has suggested their functional and physiological roles. This review summarizes the special contribution of piezoelectricity as a stimulatory signal for bone and vascular tissue regeneration, including osteogenesis, angiogenesis, vascular repair, and tissue engineering, by considering different stem cell sources entailed with osteogenic and angiogenic potential, aimed at collecting the key findings that may enable the development of successful vascularized bone replacements useful in orthopedic and otologic surgery.


Subject(s)
Bone Regeneration , Osteogenesis , Tissue Engineering , Tissue Scaffolds
15.
Bioinspir Biomim ; 17(1)2021 11 26.
Article in English | MEDLINE | ID: mdl-34700310

ABSTRACT

Architected biomaterials, as well as sound and music, are constructed from small building blocks that are assembled across time- and length-scales. Here we present a novel deep learning-enabled integrated algorithmic workflow to merge the two concepts for radical discovery ofde novoprotein materials, exploiting musical creativity as the foundation, and extrapolating through a recursive method to increase protein complexity by successively injecting protein chemistry into the process. Indeed, music is one of the few universal expressions that can create bridges between cultures, find associations between seemingly unrelated concepts, and can be used as a novel way to generate bio-inspired designs that derive functions from the imaginations of the creative mind. Earlier work has offered a pathway to convert proteins into sound, and sound into proteins. Here we build on this paradigm and translate a piece of classical music into matter. Based on Bach's Goldberg variations, we offer a series of case studies to convert the musical data imagined by the composer into protein design, and folded into a 3D structure using deep learning. The quest we seek to address is to identify semblances, or memories, or information content in such musical creation, that offers new insights into pattern relationships between distinct manifestations of information. Using basic local alignment search tool analysis, we find that several fragments of the new proteins display similarities to existing protein sequences found in proteobacteria among other organisms, especially in regions of low complexity and repetitive motifs. The resulting protein forms the basis for iterative musical composition, and an evolutionary paradigm that defines a variational pathway for melodic development, complementing conventional creative or mathematical methods. This paper broadens the concept of what is understood as bio-inspiration to include a broad array of systems created by humans, animals, or other natural mechanisms.


Subject(s)
Deep Learning , Music , Animals , Creativity , Proteins , Sound
16.
Pharmaceutics ; 13(9)2021 Sep 10.
Article in English | MEDLINE | ID: mdl-34575515

ABSTRACT

Chitin nanofibrils (CNs) are an emerging bio-based nanomaterial. Due to nanometric size and high crystallinity, CNs lose the allergenic features of chitin and interestingly acquire anti-inflammatory activity. Here we investigate the possible advantageous use of CNs in tympanic membrane (TM) scaffolds, as they are usually implanted inside highly inflamed tissue environment due to underlying infectious pathologies. In this study, the applications of CNs in TM scaffolds were twofold. A nanocomposite was used, consisting of poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) copolymer loaded with CN/polyethylene glycol (PEG) pre-composite at 50/50 (w/w %) weight ratio, and electrospun into fiber scaffolds, which were coated by CNs from crustacean or fungal sources via electrospray. The degradation behavior of the scaffolds was investigated during 4 months at 37 °C in an otitis-simulating fluid. In vitro tests were performed using cell types to mimic the eardrum, i.e., human mesenchymal stem cells (hMSCs) for connective, and human dermal keratinocytes (HaCaT cells) for epithelial tissues. HMSCs were able to colonize the scaffolds and produce collagen type I. The inflammatory response of HaCaT cells in contact with the CN-coated scaffolds was investigated, revealing a marked downregulation of the pro-inflammatory cytokines. CN-coated PEOT/PBT/(CN/PEG 50:50) scaffolds showed a significant indirect antimicrobial activity.

17.
iScience ; 24(8): 102873, 2021 Aug 20.
Article in English | MEDLINE | ID: mdl-34409268

ABSTRACT

Fire has fascinated humankind since the prehistoric era. Rooted in the interactions between sound and flames, here we report a method to use fire for a variety of purposes, including sonification, art, and the design and manufacturing nature-inspired materials. We present a method to sonify fire, thereby offering a translation from the silent nature of flames, to represent audible information and to generate de novo flame images. To realize material specimen derived from fire, we use the autoencoder to generate image stacks to yield continuous 3D geometries that are manufactured using 3D printing. This represents the first generation of nature-inspired materials from fire and can be a platform to be used for other natural phenomena in the quest for de novo architectures, geometries, and design ideas, thus creating additional directions in artistic and scientific research through the creative manipulation of data with structural similarities across fields.

18.
Front Bioeng Biotechnol ; 9: 669863, 2021.
Article in English | MEDLINE | ID: mdl-34164386

ABSTRACT

Perforation is the most common illness of the tympanic membrane (TM), which is commonly treated with surgical procedures. The success rate of the treatment could be improved by novel bioengineering approaches. In fact, a successful restoration of a damaged TM needs a supporting biomaterial or scaffold able to meet mechano-acoustic properties similar to those of the native TM, along with optimal biocompatibility. Traditionally, a large number of biological-based materials, including paper, silk, Gelfoam®, hyaluronic acid, collagen, and chitosan, have been used for TM repair. A novel biopolymer with promising features for tissue engineering applications is cellulose. It is a highly biocompatible, mechanically and chemically strong polysaccharide, abundant in the environment, with the ability to promote cellular growth and differentiation. Bacterial cellulose (BC), in particular, is produced by microorganisms as a nanofibrous three-dimensional structure of highly pure cellulose, which has thus become a popular graft material for wound healing due to a number of remarkable properties, such as water retention, elasticity, mechanical strength, thermal stability, and transparency. This review paper provides a comprehensive overview of the current experimental studies of BC, focusing on the application of BC patches in the treatment of TM perforations. In addition, computational approaches to model cellulose and TM are summarized, with the aim to synergize the available tools toward the best design and exploitation of BC patches and scaffolds for TM repair and regeneration.

19.
Biomater Sci ; 9(9): 3390-3400, 2021 May 04.
Article in English | MEDLINE | ID: mdl-33949363

ABSTRACT

Bone is mineralized tissue constituting the skeletal system, supporting and protecting the body's organs and tissues. In addition to such fundamental mechanical functions, bone also plays a remarkable role in sound conduction. From a mechanical standpoint, bone is a composite material consisting of minerals and collagen arranged in multiple hierarchical structures, with a complex anisotropic viscoelastic response, capable of transmitting and dissipating energy. At the molecular level, mineralized collagen fibrils are the basic building blocks of bone tissue, and hence, understanding bone properties down to fundamental tissue structures enables better identification of the mechanisms of structural failures and damage. While efforts have focused on the study of micro- and macro-scale viscoelasticity related to bone damage and healing based on creep, mineralized collagen has not been explored at the molecular level. We report a study that aims at systematically exploring the viscoelasticity of collagenous fibrils with different mineralization levels. We investigate the dynamic mechanical response upon cyclic and impulsive loads to observe the viscoelastic phenomena from either shear or extensional strains via molecular dynamics. We perform a sensitivity analysis with several key benchmarks: intrafibrillar mineralization percentage, hydration state, and external load amplitude. Our results show an increase of the dynamic moduli with an increase of the mineral percentage, pronounced at low strains. When intrafibrillar water is present, the material softens the elastic component, but considerably increases its viscosity, especially at high frequencies. This behavior is confirmed from the material response upon impulsive loads, in which water drastically reduces the relaxation times throughout the input velocity range by one order of magnitude, with respect to the dehydrated counterparts. We find that, upon transient loads, water has a major impact on the mechanics of mineralized fibrillar collagen, being able to improve the capability of the tissue to passively and effectively dissipate energy, especially after fast and high-amplitude external loads. Our study provides knowledge of bone mechanics in relation to pathologies deriving from dehydration or traumas. Moreover, these findings show the potential for being used in designing new bioinspired materials not limited to tissue engineering applications, in which passive mechanisms for dissipating energy can prevent structural failures.


Subject(s)
Extracellular Matrix , Fibrillar Collagens , Bone and Bones , Collagen , Viscosity
20.
Acta Myol ; 40(4): 143-151, 2021 Dec.
Article in English | MEDLINE | ID: mdl-35047754

ABSTRACT

Inherited muscular dystrophies and congenital myopathies present in early childhood with progressive muscle weakness, determining severe motor limitations. Active surveillance and management of associated complications have improved ambulation, function, quality of life and life expectancy. The need for repeatable, objective and quantitative measures to monitor the clinical course of the disease is a current issue, particularly in the new era where new flows of therapies are proposed to the patients. In this scenario, we designed and tested a wearable device termed AUTOMA that is able to provide quantification of the muscular impairment in the upper limb upon isokinetic tests through the integration of a force sensor and an electric goniometer. This allows qualitatively estimating the muscular functions with a systematic procedure. We carried out a preliminary pilot study on 9 patients that revealed the suitability of AUTOMA as an objective measurement tool for diagnosing and monitoring neuromuscular disorders, and opens to a more extensive clinical study in which to test and validate our platform intensively.


Subject(s)
Neuromuscular Diseases , Wearable Electronic Devices , Child, Preschool , Humans , Neuromuscular Diseases/diagnosis , Pilot Projects , Quality of Life , Upper Extremity
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