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1.
Int J Biol Macromol ; 269(Pt 2): 132141, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38723809

RESUMEN

To enhance the flame retardancy and mechanical performance of PLA, a polyelectrolyte complex predicated on lignin was obtained by electrostatic mutual adsorption of ammonium polyphosphate (APP), polyethyleneimine (PEI), and copper ions as raw materials. The FT-IR spectra and EDX analysis confirmed the successful synthesis of a lignin-based flame retardant hybrid (APL-Cu2+) containing copper, phosphorus, and nitrogen elements. The combustion test results showed that the peak heat release rate and total heat release of the PLA composite containing 12 wt% APL-Cu2+ were decreased by 15.1 % and 18.2 %, respectively, as compared to those of pure PLA. The char residue morphology observation revealed that the addition of APL-Cu2+ could promote the formation of a highly dense and stable graphitized char layer, while TG-MS detected the emission of refractory gases such as ammonia gas, carbon dioxide, and water during combustion. The strong hydrogen bonding between APL-Cu2+ and the PLA matrix kept the composite maintaining good strength and toughness. The tensile strength and impact strength of PLA/6APL-Cu2+ increased by 4.73 % and 65.71 %, respectively, due to its high crystallinity and good interfacial compatibility. This work provides a feasible method to develop biobased flame retardant hybrids for PLA composites with better fire safety and improved mechanical properties.


Asunto(s)
Cobre , Retardadores de Llama , Lignina , Poliésteres , Lignina/química , Cobre/química , Poliésteres/química , Incendios/prevención & control , Fenómenos Mecánicos , Resistencia a la Tracción , Espectroscopía Infrarroja por Transformada de Fourier , Polietileneimina/química
2.
Med Eng Phys ; 127: 104166, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38692765

RESUMEN

A profound investigation of the interaction mechanics between blood vessels and guidewires is necessary to achieve safe intervention. An interactive force model between guidewires and blood vessels is established based on cardiovascular fluid dynamics theory and contact mechanics, considering two intervention phases (straight intervention and contact intervention at a corner named "J-vessel"). The contributing factors of the force model, including intervention conditions, guidewire characteristics, and intravascular environment, are analyzed. A series of experiments were performed to validate the availability of the interactive force model and explore the effects of influential factors on intervention force. The intervention force data were collected using a 2-DOF mechanical testing system instrumented with a force sensor. The guidewire diameter and material were found to significantly impact the intervention force. Additionally, the intervention force was influenced by factors such as blood viscosity, blood vessel wall thickness, blood flow velocity, as well as the interventional velocity and interventional mode. The experiment of the intervention in a coronary artery physical vascular model confirms the practicality validation of the predicted force model and can provide an optimized interventional strategy for vascular interventional surgery. The enhanced intervention strategy has resulted in a considerable reduction of approximately 21.97 % in the force exerted on blood vessels, effectively minimizing the potential for complications associated with the interventional surgery.


Asunto(s)
Fenómenos Mecánicos , Vasos Sanguíneos/fisiología , Modelos Cardiovasculares , Hidrodinámica , Humanos , Fenómenos Biomecánicos , Modelos Biológicos , Vasos Coronarios/fisiología
3.
Int J Biol Macromol ; 268(Pt 1): 131464, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38702248

RESUMEN

Global concerns over environmental damage caused by non-biodegradable single-use packaging have sparked interest in developing biomaterials. The food packaging industry is a major contributor to non-degradable plastic waste. This study investigates the impact of incorporating different concentrations of polyvinyl alcohol (PVA) and yerba mate extract as a natural antioxidant into carboxymethyl cassava starch films to possibly use as active degradable packaging to enhance food shelf life. Films with starch and PVA blends (SP) at different ratios (SP radios of 100:0, 90:10, 80:20 and 70:30) with and without yerba mate extract (Y) were successfully produced through extrusion and thermoforming. The incorporation of up to 20 wt% PVA improved starch extrusion processing and enhanced film transparency. PVA played a crucial role in improving the hydrophobicity, tensile strength and flexibility of the starch films but led to a slight deceleration in their degradation in compost. In contrast, yerba mate extract contributed to better compost degradation of the blend films. Additionally, it provided antioxidant activity, particularly in hydrophilic and lipophilic food simulants, suggesting its potential to extend the shelf life of food products. Starch-PVA blend films with yerba mate extract emerged as a promising alternative for mechanically resistant and active food packaging.


Asunto(s)
Antioxidantes , Embalaje de Alimentos , Manihot , Extractos Vegetales , Alcohol Polivinílico , Almidón , Embalaje de Alimentos/métodos , Alcohol Polivinílico/química , Almidón/química , Almidón/análogos & derivados , Antioxidantes/química , Manihot/química , Extractos Vegetales/química , Ilex paraguariensis/química , Resistencia a la Tracción , Interacciones Hidrofóbicas e Hidrofílicas , Fenómenos Mecánicos
4.
Int J Biol Macromol ; 269(Pt 1): 131951, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38710253

RESUMEN

Bacterial nanocellulose (BNC) is a promising material for heart valve prostheses. However, its low strength properties limit its applicability in cardiovascular surgery. To overcome these limitations, the mechanical properties of BNC can be improved through modifications. The aim of the research was to investigate the extent to which the mechanical properties of BNC can be altered by modifying its structure during its production and after synthesis. The study presents the results of various analyses, including tensile tests, nanoindentation tests, X-ray diffraction (XRD) tests, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy, conducted on BNC chemically modified in situ with hyaluronic acid (BNC/HA) and physically modified ex situ through a dehydration/rehydration process (BNC 25DR, BNC105DR, BNC FDR and BNC/HA 25DR, BNC/HA 105DR, BNC/HA FDR). The results demonstrate that both chemical and physical modifications can effectively shape the mechanical properties of BNC. These modifications induce changes in the crystalline structure, pore size and distribution, and residual stresses of BNC. Results show the effect of the crystalline structure of BNC on its mechanical properties. There is correlation between hardness and Young's modulus and Iα/Iß index for BNC/HA and between creep rate of BNC/HA, and Young's modulus for BNC vs Iα/Iß index.


Asunto(s)
Celulosa , Celulosa/química , Prótesis Valvulares Cardíacas , Resistencia a la Tracción , Difracción de Rayos X , Nanoestructuras/química , Espectroscopía Infrarroja por Transformada de Fourier , Ensayo de Materiales , Ácido Hialurónico/química , Fenómenos Mecánicos , Válvulas Cardíacas/química
5.
Int J Biol Macromol ; 266(Pt 2): 131393, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38582476

RESUMEN

Biocomposites developed using natural fibers serve as a sustainable alternative to synthetic composite materials. However, narrowing the performance gap between synthetic composites and biocomposites requires serious efforts. A promising approach is the modification of natural fibers using various chemical treatments. This paper investigates the potential of tannic acid (TA) treatment as a sustainable approach to enhance mechanical performance and reduce moisture absorption of flax fabric-reinforced biocomposites. The methodology involves the treatment of flax woven fabric with tannic acid, a naturally occurring polyphenolic compound, followed by the fabrication of biocomposite using a green epoxy matrix. The variables studied during treatment are TA concentration and processing time. Characterization of untreated and treated flax fabric and its composites was done using various analytical techniques such as FTIR spectroscopy, moisture absorption and mechanical testing (tensile strength, flexural strength, and impact resistance). FTIR spectroscopy of TA-treated flax confirmed attachment of aromatic rings and carbon double bond formation, thus serving for properties enhancement. The mechanical characterization of composites showed that properties are enhanced up to an optimum limit of concentration and processing time i.e., 1 % concentration and 30 min of processing. Moisture absorption of the TA-treated composite also reduced significantly as compared to untreated composites. These findings contribute towards the advancement in sustainable biocomposites and pave the way for their utilization in various applications.


Asunto(s)
Lino , Polifenoles , Taninos , Resistencia a la Tracción , Textiles , Taninos/química , Lino/química , Espectroscopía Infrarroja por Transformada de Fourier , Fenómenos Mecánicos , Materiales Biocompatibles/química
6.
Int J Biol Macromol ; 268(Pt 2): 131942, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38685546

RESUMEN

The interaction of monoglycerides and phytosterols in olive- and coconut oil on the structuring of oleogels was analyzed. Specifically, bigels with gelatin hydrogel in different ratios (40:60 and 60:40 w/w) were formed. The physicochemical and microstructural attributes of these systems were assessed. The olive oil to coconut oil ratio (0-100 w/w) and the added oleogelators affected the crystal structure and the mechanical properties of the oleogels. Polarized light microscopy revealed that the addition of coconut oil created a denser triglycerides crystal network and the presence of phytosterols created more needle-like crystals, enhancing the textural properties of the oleogels and of the resulting bigels. The hardness of the oleogels ranged from 0.50 N to 1.24 N and for bigels was 5.96-36.75 N. Bigels hardness decreased as the oleogel ratio in the bigel increased. Microscopy and FTIR revealed that the addition of coconut oil in oleogels hampered the formation of a distinct crystalline monoglycerides network. Also, the absence of new peaks in the bigels indicated that the two structured phases interact with each other mostly physically, without the formation of new chemical bonds. Consequently, the oleogels and bigels developed, comprise a promising hard fat substitute with improved nutritional profile.


Asunto(s)
Aceite de Coco , Aceite de Oliva , Compuestos Orgánicos , Compuestos Orgánicos/química , Aceite de Coco/química , Aceite de Oliva/química , Monoglicéridos/química , Gelatina/química , Fenómenos Mecánicos , Triglicéridos/química , Fitosteroles/química , Dureza , Espectroscopía Infrarroja por Transformada de Fourier
7.
Int J Biol Macromol ; 269(Pt 2): 131894, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38677674

RESUMEN

N-methyl-morpholine-N-oxide (NMMO) was initially created as a plasticizer for starch to produce thermoplastic wheat starch. Subsequently, talc powder was used as a reinforcing filler to enhance the mechanical strength of thermoplastic biomass-based composite plastics. The chemical structure, crystal structure, and microscopic morphology were analyzed using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Additionally, the thermal properties were explored through thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. The hydrated NMMO plasticizer demonstrated an outstanding plasticizing effect on starch, resulting in a composite with remarkable mechanical properties. In fact, the pure thermoplastic wheat starch plasticized with hydrated NMMO exhibited the highest mechanical strength recorded so far, with a tensile strength of up to 9.4 MPa. In addition, talcum powder displayed a noticeable reinforcing effect. When the talcum powder content reached 30 wt%, the targeted composite achieved a tensile strength of 20.5 MPa and a Young's modulus of 177.9 MPa. These values were 118 % and 48 % higher, respectively, than those of the pure thermoplastic starch sample. This innovative plasticizing method opens up a new avenue for the development of high-mechanical-strength thermoplastic biomass-based composite plastics with promising potential applications.


Asunto(s)
Biomasa , Plastificantes , Plásticos , Almidón , Talco , Resistencia a la Tracción , Triticum , Almidón/química , Talco/química , Triticum/química , Plásticos/química , Plastificantes/química , Polvos , Espectroscopía Infrarroja por Transformada de Fourier , Termogravimetría , Fenómenos Mecánicos , Difracción de Rayos X
8.
J Am Chem Soc ; 146(11): 7233-7242, 2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38451498

RESUMEN

The T cell membrane is studded with >104 T cell receptors (TCRs) that are used to scan target cells to identify short peptide fragments associated with viral infection or cancerous mutation. These peptides are presented as peptide-major-histocompatibility complexes (pMHCs) on the surface of virtually all nucleated cells. The TCR-pMHC complex forms at cell-cell junctions, is highly transient, and experiences mechanical forces. An important question in this area pertains to the role of the force duration in immune activation. Herein, we report the development of force probes that autonomously terminate tension within a time window following mechanical triggering. Force-induced site-specific enzymatic cleavage (FUSE) probes tune the tension duration by controlling the rate of a force-triggered endonuclease hydrolysis reaction. This new capability provides a method to study how the accumulated force duration contributes to T cell activation. We screened DNA sequences and identified FUSE probes that disrupt mechanical interactions with F > 7.1 piconewtons (pN) between TCRs and pMHCs. This rate of disruption, or force lifetime (τF), is tunable from tens of minutes down to 1.9 min. T cells challenged with FUSE probes with F > 7.1 pN presenting cognate antigens showed up to a 23% decrease in markers of early activation. FUSE probes with F > 17.0 pN showed weaker influence on T cell triggering further showing that TCR-pMHC with F > 17.0 pN are less frequent compared to F > 7.1 pN. Taken together, FUSE probes allow a new strategy to investigate the role of force dynamics in mechanotransduction broadly and specifically suggest a model of serial mechanical engagement boosting TCR activation.


Asunto(s)
Mecanotransducción Celular , Receptores de Antígenos de Linfocitos T , Receptores de Antígenos de Linfocitos T/metabolismo , Linfocitos T , Activación de Linfocitos , Fenómenos Mecánicos , Péptidos/química , Unión Proteica
9.
J Mech Behav Biomed Mater ; 154: 106523, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38554581

RESUMEN

A theoretical framework, united by a "system effect" is formulated to model the cutting/haptic force evolution at the cutting edge of a surgical cutting instrument during its penetration into soft biological tissue in minimally invasive surgery. Other cutting process responses, including tissue fracture force, friction force, and damping, are predicted by the model as well. The model is based on a velocity-controlled formulation of the corresponding equations of motion, derived for a surgical cutting instrument and tissue based on Kirchhoff's fundamental energy conservation law. It provides nearly zero residues (absolute errors) in the equations of motion balances. In addition, concurrent closing relationships for the fracture force, friction coefficient, friction force, process damping, strain rate function (a constitutive tissue model), and their implementation within the proposed theoretical framework are established. The advantage of the method is its ability to make precise real-time predictions of the aperiodic fluctuating evolutions of the cutting forces and the other process responses. It allows for the robust modeling of the interactions between a medical instrument and a nonlinear viscoelastic tissue under any physically feasible working conditions. The cutting process model was partially qualitatively verified through numerical simulations and by comparing the computed cutting forces with experimentally measured values during robotic uniaxial biopsy needle constant velocity insertion into artificial gel tissue, obtained from previous experimental research. The comparison has shown a qualitatively similar adequate trend in the evolution of the experimentally measured and numerically predicted cutting forces during insertion of the needle.


Asunto(s)
Fenómenos Mecánicos , Agujas , Biopsia con Aguja , Movimiento (Física) , Procedimientos Quirúrgicos Mínimamente Invasivos
10.
Eur J Pharm Biopharm ; 197: 114221, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38378097

RESUMEN

The development of PFS requires a detailed understanding of the forces occurring during the drug administration process and patient's capability. This research describes an advanced mathematic injection force model that consisting hydrodynamic force and friction force. The hydrodynamic force follows the basic law of Hagen-Poiseuille but refines the modeling approach by delving into specific properties of drug viscosity (Newtonian and Shear-thinning) and syringe shape constant, while the friction force was accounted from empty barrel injection force. Additionally, we take actual temperature of injection into consideration, providing more accurate predication. The results show that the derivation of the needle dimension constant and the rheological behavior of the protein solutions are critical parameters. Also, the counter pressure generated by the tissue has been considered in actual administration to address the issue of the inaccuracies of current injection force evaluation preformed in air, especially when the viscosity of the injected drug solution is below 9.0 cP (injecting with 1 mL L PFS staked with 29G ½ inch needle). Human factor studies on patients' capability against medication viscosity filled the gap in design space of PFS drug product and available viscosity data in very early phase.


Asunto(s)
Fenómenos Mecánicos , Jeringas , Humanos , Viscosidad , Inyecciones , Preparaciones Farmacéuticas
11.
Biomolecules ; 14(2)2024 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-38397421

RESUMEN

Tumor diseases become a huge problem when they embark on a path that advances to malignancy, such as the process of metastasis. Cancer metastasis has been thoroughly investigated from a biological perspective in the past, whereas it has still been less explored from a physical perspective. Until now, the intraluminal pathway of cancer metastasis has received the most attention, while the interaction of cancer cells with macrophages has received little attention. Apart from the biochemical characteristics, tumor treatments also rely on the tumor microenvironment, which is recognized to be immunosuppressive and, as has recently been found, mechanically stimulates cancer cells and thus alters their functions. The review article highlights the interaction of cancer cells with other cells in the vascular metastatic route and discusses the impact of this intercellular interplay on the mechanical characteristics and subsequently on the functionality of cancer cells. For instance, macrophages can guide cancer cells on their intravascular route of cancer metastasis, whereby they can help to circumvent the adverse conditions within blood or lymphatic vessels. Macrophages induce microchannel tunneling that can possibly avoid mechanical forces during extra- and intravasation and reduce the forces within the vascular lumen due to vascular flow. The review article highlights the vascular route of cancer metastasis and discusses the key players in this traditional route. Moreover, the effects of flows during the process of metastasis are presented, and the effects of the microenvironment, such as mechanical influences, are characterized. Finally, the increased knowledge of cancer metastasis opens up new perspectives for cancer treatment.


Asunto(s)
Neoplasias , Microambiente Tumoral , Humanos , Señales (Psicología) , Neoplasias/metabolismo , Macrófagos/metabolismo , Fenómenos Mecánicos , Metástasis de la Neoplasia/patología
12.
Adv Sci (Weinh) ; 11(12): e2305537, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38225742

RESUMEN

In minimally invasive surgery, such as cardiac ablation, magnetically steered catheters made of variable-stiffness materials can enable higher dexterity and higher force application to human tissue. However, the long transition time between soft and rigid states leads to a significant increase in procedure duration. Here, a fast-response, multisegmented catheter is described for minimally invasive surgery made of variable-stiffness thread (FRVST) that encapsulates a helical cooling channel. The rapid stiffness change in the FRVST, composed of a nontoxic shape memory polymer, is achieved by an active cooling system that pumps water through the helical channel. The FRVST displays a 66 times stiffness change and a 26 times transition enhancement compare with the noncooled version. The catheter allows for selective bending of each segment up to 127° in air and up to 76° in water under an 80 mT external magnetic field. The inner working channel can be used for cooling an ablation tip during a procedure and for information exchange via the deployment of wires or surgical tools.


Asunto(s)
Catéteres , Procedimientos Quirúrgicos Mínimamente Invasivos , Humanos , Fenómenos Mecánicos , Agua , Fenómenos Magnéticos
13.
Nanoscale Horiz ; 9(3): 365-383, 2024 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-38230559

RESUMEN

Precision drug delivery and multimodal synergistic therapy are crucial in treating diverse ailments, such as cancer, tissue damage, and degenerative diseases. Electrodes that emit electric pulses have proven effective in enhancing molecule release and permeability in drug delivery systems. Moreover, the physiological electrical microenvironment plays a vital role in regulating biological functions and triggering action potentials in neural and muscular tissues. Due to their unique noncentrosymmetric structures, many 2D materials exhibit outstanding piezoelectric performance, generating positive and negative charges under mechanical forces. This ability facilitates precise drug targeting and ensures high stimulus responsiveness, thereby controlling cellular destinies. Additionally, the abundant active sites within piezoelectric 2D materials facilitate efficient catalysis through piezochemical coupling, offering multimodal synergistic therapeutic strategies. However, the full potential of piezoelectric 2D nanomaterials in drug delivery system design remains underexplored due to research gaps. In this context, the current applications of piezoelectric 2D materials in disease management are summarized in this review, and the development of drug delivery systems influenced by these materials is forecast.


Asunto(s)
Nanoestructuras , Nanoestructuras/uso terapéutico , Nanoestructuras/química , Electricidad , Fenómenos Mecánicos , Sistemas de Liberación de Medicamentos
14.
Orthopadie (Heidelb) ; 53(1): 47-55, 2024 Jan.
Artículo en Alemán | MEDLINE | ID: mdl-38095661

RESUMEN

INTRODUCTION: In revision surgery, modular implant components allow the surgeon to tailor the characteristics of the implant to the bone situation. Relative motion can occur at the tapered modular connection, leading to fretting corrosion and subsequent biological reactions, particularly due to poor assembly and contamination of the tapered connection. The aim of this study was to demonstrate whether incomplete assembly and inadvertent contamination of the modular taper causes a change in junction strength. MATERIAL AND METHODS: Modular taper junctions between the neck and the stem (n = 48) were divided into seven groups that differed with respect to contamination (native, contaminated, cleaned) and assembly conditions (secured, pre-tensioned and secured). Contamination was achieved by a combination of porcine bone particles and bovine blood. For each group, the number of rotations of the torque limiter while securing the conical connection was recorded. The implants were subjected to cyclic loading. DIC was used to determine neck rotation, micromotion and axial subsidence. Loosening torque of the locking screw and pull-off forces were measured as an equivalent of residual taper junction strength. RESULTS: Contamination of the taper junction, especially in combination with improper assembly of the components, significantly increased the rotation (35.3 ± 13.7° vs. 2.4 ± 4.4°; p <0.001), micromotion (67.8 ± 16.9 µm vs. 5.1 ± 12.1 µm, p <0.001) and axial subsidence (­34.1 ± 16.9 µm vs. 4.3 ± 10.9 µm; p <0.001) of the neck relative to the stem. CONCLUSION: Intra-operatively, contamination of the taper surface can be identified by the need for multiple turns when tightening the locking screw. Correct cleaning with the new taper cleaning instrument and complete assembly with pre-tensioning may reduce the risk of early failure and fatigue fracture of the modular taper connection.


Asunto(s)
Artroplastia de Reemplazo de Cadera , Prótesis de Cadera , Animales , Bovinos , Diseño de Prótesis , Falla de Prótesis , Fenómenos Mecánicos
15.
J Stomatol Oral Maxillofac Surg ; 125(1): 101642, 2024 02.
Artículo en Inglés | MEDLINE | ID: mdl-37739222

RESUMEN

OBJECTIVE: Bilateral sagittal split ramus osteotomy (BSSRO) and bimaxillary osteotomies (BSSRO plus Lefort1 osteotomy) are widely used to solve maxillofacial deformities. The effect of the surgeries on the temporomandibular joint (TMJ) is still not clear. The purpose of this study was to investigate the preoperative and postoperative stress environment of the patients and to compare the biomechanical differences of the two surgeries. METHODS: Ten patients were performed BSSRO and fourteen underwent bimaxillary osteotomies. Eleven asymptomatic subjects were recruited to be the control group. The muscle forces of incisal clenching were applied on the finite element models. And contact was used to simulate the interactions within the TMJs. RESULTS: two kinds of surgeries could not completely eliminate the negative biomechanical distribution within the TMJs. CONCLUSION: Compared to BSSRO only, the bimaxillary osteotomies could better repair the biomechanical environment of the TMJs under incisal clenching. And the TMD symptoms were strongly related to the stress distributions of the TMJs.


Asunto(s)
Mandíbula , Osteotomía Sagital de Rama Mandibular , Humanos , Osteotomía Sagital de Rama Mandibular/efectos adversos , Mandíbula/cirugía , Articulación Temporomandibular/cirugía , Fenómenos Mecánicos
16.
Small ; 20(7): e2303962, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37789502

RESUMEN

Previous on-chip technologies for characterizing the cellular mechanical properties often suffer from a low throughput and limited sensitivity. Herein, an inertial multi-force deformability cytometry (IMFDC) is developed for high-throughput, high-accuracy, and high-applicability tumor cell mechanotyping. Three different deformations, including shear deformations and stretch deformations under different forces, are integrated with the IMFDC. The 3D inertial focusing of cells enables the cells to deform by an identical fluid flow, and 10 parameters, such as cell area, perimeter, deformability, roundness, and rectangle deformability, are obtained in three deformations. The IMFDC is able to evaluate the deformability of different cells that are sensitive to different forces on a single chip, demonstrating the high applicability of the IMFDC in analyzing different cell lines. In identifying cell types, the three deformations exhibit different mechanical responses to cells with different sizes and deformability. A discrimination accuracy of ≈93% for both MDA-MB-231 and MCF-10A cells and a throughput of ≈500 cells s-1 can be achieved using the multiple-parameters-based machine learning model. Finally, the mechanical properties of metastatic tumor cells in pleural and peritoneal effusions are characterized, enabling the practical application of the IMFDC in clinical cancer diagnosis.


Asunto(s)
Técnicas Analíticas Microfluídicas , Neoplasias , Humanos , Fenómenos Mecánicos , Citometría de Flujo
17.
Int J Comput Assist Radiol Surg ; 19(2): 209-221, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37787938

RESUMEN

PURPOSE: The development of cardiovascular interventional surgery robots can realize master-slave interventional operations, which will effectively solve the problem of surgeons being injured by X-ray radiation. The delivery accuracy and safety of interventional instruments such as guidewire are the most important issues in the development of robotic systems. Most of the current control methods are position control or force feedback control, which cannot take into account delivery accuracy and safety. METHODS: A cardiovascular interventional surgery robotic system integrated force sensors is developed. A novel force/position controller, which includes a radial basis function neural networks-based inner loop position controller and a force-based admittance outer loop controller, is proposed. Furthermore, a series of simulations and vascular model experiments are carried out to demonstrate the feasibility and accuracy of the proposed controller. RESULTS: The designed cardiovascular interventional robot is flexible to enter the target vessel branch. Experimental results indicate that the proposed controller can effectively improve the delivery accuracy of the guidewire and reduce the contact force with the vessel wall. CONCLUSIONS: The proposed controller based on radial basis function neural network and admittance control is effective in improving delivery accuracy and reducing contact force. The algorithm needs to be further validated in vivo experiments.


Asunto(s)
Procedimientos Quirúrgicos Robotizados , Robótica , Humanos , Procedimientos Quirúrgicos Vasculares/métodos , Diseño de Equipo , Fenómenos Mecánicos
18.
Biomech Model Mechanobiol ; 23(1): 145-155, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37770729

RESUMEN

Multi-cellular biomimetic models often comprise heterogenic geometries. Therefore, quantification of their mechanical properties-which is crucial for various biomedical applications-is a challenge. Due to its simplicity, linear fitting is traditionally used in analyzing force-displacement data of parallel compression measurements of multi-cellular clusters, such as tumor spheroids. However, the linear assumption would be artificial when the contact geometry is not planar. We propose here the integrated elasticity (IE) regression, which is based on extrapolation of established elastic theories for well-defined geometries, and is free, extremely simple to apply, and optimal for analyzing coarsely concave multi-cellular clusters. We studied here the quality of the data analysis in force measurements of tumor spheroids comprising different types of melanoma cells, using either the IE or the traditional linear regressions. The IE regression maintained excellent precision also when the contact geometry deviated from planarity (as shown by our image analysis). While the quality of the linear fittings was relatively satisfying, these predicted smaller elastic moduli as compared to the IE regression. This was in accordance with previous studies, in which the elastic moduli predicted by linear fits were smaller compared to those obtained by well-established methods. This suggests that linear regressions underestimate the elastic constants of bio-samples even in cases where the fitting precision seems satisfying, and highlights the need in alternative methods as the IE scheme. For comparison between different types of spheroids we further recommend to increase the soundness by regarding relative moduli, using universal reference samples.


Asunto(s)
Fenómenos Mecánicos , Neoplasias , Humanos , Elasticidad , Módulo de Elasticidad
19.
J Orthop Res ; 42(5): 1045-1053, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38032092

RESUMEN

It remains unknown if hip joint forces during squat tasks are altered in people with femoroacetabular impingement syndrome (FAIS). The aim of this study is to compare hip joint forces between people with FAIS and healthy controls during double leg squat and single leg squat tasks and within limbs during a single leg squat task in people with FAIS. Kinematic and kinetic data were collected in eight people with FAIS and eight healthy matched controls using 3D motion capture and force plates. AnyBody Modeling System was used to perform musculoskeletal simulations to estimate hip joint angles, forces, and moments for all participants. Estimates were postprocessed with AnyPyTools and converted into normalized time series to be compared using a 1D statistical nonparametric mapping (SnPM) approach. SnPM with an independent samples t-test model was used to compare people with FAIS to controls, while a paired samples model was used to compare involved to uninvolved limb in people with FAIS. Patients demonstrated lower proximodistal force compared to controls (p < 0.01) and compared to the uninvolved side (p = 0.01) for single leg squat. The smaller joint contact forces in people with FAIS compared to controls could represent a strategy of reduced muscle forces to avoid pain and symptoms during this high demand task. These findings when combined with imaging data could help assess the severity of FAIS on hip related function during higher demand tasks.


Asunto(s)
Pinzamiento Femoroacetabular , Humanos , Estudios de Casos y Controles , Articulación de la Cadera , Postura , Fenómenos Mecánicos , Artroscopía
20.
Microsc Res Tech ; 87(4): 631-659, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38053519

RESUMEN

Single-cell analysis is an emerging and promising frontier in the field of life sciences, which is expected to facilitate the exploration of fundamental laws of physiological and pathological processes. Single-cell analysis allows experimental access to cell-to-cell heterogeneity to reveal the distinctive behaviors of individual cells, offering novel opportunities to dissect the complexity of severe human diseases such as cancers. Among the single-cell analysis tools, atomic force microscopy (AFM) is a powerful and versatile one which is able to nondestructively image the fine topographies and quantitatively measure multiple mechanical properties of single living cancer cells in their native states under aqueous conditions with unprecedented spatiotemporal resolution. Over the past few decades, AFM has been widely utilized to detect the structural and mechanical behaviors of individual cancer cells during the process of tumor formation, invasion, and metastasis, yielding numerous unique insights into tumor pathogenesis from the biomechanical perspective and contributing much to the field of cancer mechanobiology. Here, the achievements of AFM-based analysis of single cancer cells to advance physical oncology are comprehensively summarized, and challenges and future perspectives are also discussed. RESEARCH HIGHLIGHTS: Achievements of AFM in characterizing the structural and mechanical behaviors of single cancer cells are summarized, and future directions are discussed. AFM is not only capable of visualizing cellular fine structures, but can also measure multiple cellular mechanical properties as well as cell-generated mechanical forces. There is still plenty of room for harnessing AFM-based single-cell analysis to advance physical oncology.


Asunto(s)
Fenómenos Mecánicos , Neoplasias , Humanos , Microscopía de Fuerza Atómica/métodos , Análisis de la Célula Individual
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