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1.
Sensors (Basel) ; 24(14)2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39066045

RESUMO

Muscle dysfunction and muscle atrophy are common complications resulting from Chronic Obstructive Pulmonary Disease (COPD). The evaluation of the peripheral muscles can be carried out through the assessment of their structural components from ultrasound images or their functional components through isometric and isotonic strength tests. This evaluation, performed mainly on the quadriceps muscle, is not only of great interest for diagnosis, prognosis and monitoring of COPD, but also for the evaluation of the benefits of therapeutic interventions. In this work, bioimpedance spectroscopy technology is proposed as a low-cost and easy-to-use alternative for the evaluation of peripheral muscles, becoming a feasible alternative to ultrasound images and strength tests for their application in routine clinical practice. For this purpose, a laboratory prototype of a bioimpedance device has been adapted to perform segmental measurements in the quadriceps region. The validation results obtained in a pseudo-randomized study in patients with COPD in a controlled clinical environment which involved 33 volunteers confirm the correlation and correspondence of the bioimpedance parameters with respect to the structural and functional parameters of the quadriceps muscle, making it possible to propose a set of prediction equations. The main contribution of this manuscript is the discovery of a linear relationship between quadriceps muscle properties and the bioimpedance Cole model parameters, reaching a correlation of 0.69 and an average error of less than 0.2 cm regarding the thickness of the quadriceps estimations from ultrasound images, and a correlation of 0.77 and an average error of 3.9 kg regarding the isometric strength of the quadriceps muscle.


Assuntos
Impedância Elétrica , Doença Pulmonar Obstrutiva Crônica , Humanos , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Doença Pulmonar Obstrutiva Crônica/diagnóstico por imagem , Masculino , Músculo Quadríceps/fisiopatologia , Músculo Quadríceps/diagnóstico por imagem , Músculo Quadríceps/fisiologia , Pessoa de Meia-Idade , Idoso , Feminino , Espectroscopia Dielétrica/métodos , Espectroscopia Dielétrica/instrumentação , Força Muscular/fisiologia , Músculo Esquelético/fisiopatologia , Músculo Esquelético/diagnóstico por imagem
2.
Sensors (Basel) ; 22(22)2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36433511

RESUMO

This paper presents the design, development, and testing of an IoT-enabled smart stick for visually impaired people to navigate the outside environment with the ability to detect and warn about obstacles. The proposed design employs ultrasonic sensors for obstacle detection, a water sensor for sensing the puddles and wet surfaces in the user's path, and a high-definition video camera integrated with object recognition. Furthermore, the user is signaled about various hindrances and objects using voice feedback through earphones after accurately detecting and identifying objects. The proposed smart stick has two modes; one uses ultrasonic sensors for detection and feedback through vibration motors to inform about the direction of the obstacle, and the second mode is the detection and recognition of obstacles and providing voice feedback. The proposed system allows for switching between the two modes depending on the environment and personal preference. Moreover, the latitude/longitude values of the user are captured and uploaded to the IoT platform for effective tracking via global positioning system (GPS)/global system for mobile communication (GSM) modules, which enable the live location of the user/stick to be monitored on the IoT dashboard. A panic button is also provided for emergency assistance by generating a request signal in the form of an SMS containing a Google maps link generated with latitude and longitude coordinates and sent through an IoT-enabled environment. The smart stick has been designed to be lightweight, waterproof, size adjustable, and has long battery life. The overall design ensures energy efficiency, portability, stability, ease of access, and robust features.


Assuntos
Tecnologia Assistiva , Auxiliares Sensoriais , Pessoas com Deficiência Visual , Humanos , Desenho de Equipamento , Bengala
3.
Sensors (Basel) ; 21(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34450744

RESUMO

A MedRadio RF receiver integrated circuit for implanted and wearable biomedical devices must be resilient to the out-of-band (OOB) orthogonal frequency division modulation (OFDM) blocker. As the OFDM is widely adopted for various broadcasting and communication systems in the ultra-high frequency (UHF) band, the selectivity performance of the MedRadio RF receiver can severely deteriorate by the second-order intermodulation (IM2) distortion induced by the OOB OFDM blocker. An analytical investigation shows how the OFDM-induced IM2 distortion power can be translated to an equivalent two-tone-induced IM2 distortion power. It makes the OFDM-induced IM2 analysis and characterization process for a MedRadio RF receiver much simpler and more straightforward. A MedRadio RF receiver integrated circuit with a significantly improved resilience to the OOB IM2 distortion is designed in 65 nm complementary metal-oxide-semiconductor (CMOS). The designed RF receiver is based on low-IF architecture, comprising a low-noise amplifier, single-to-differential transconductance stage, quadrature passive mixer, trans-impedance amplifier (TIA), image-rejecting complex bandpass filter, and fractional phase-locked loop synthesizer. We describe design techniques for the IM2 calibration through the gate bias tuning at the mixer, and the dc offset calibration that overcomes the conflict with the preceding IM2 calibration through the body bias tuning at the TIA. Measured results show that the OOB carrier-to-interference ratio (CIR) performance is significantly improved by 4-11 dB through the proposed IM2 calibration. The measured maximum tolerable CIR is found to be between -40.2 and -71.2 dBc for the two-tone blocker condition and between -70 and -77 dBc for the single-tone blocker condition. The analytical and experimental results of this work will be essential to improve the selectivity performance of a MedRadio RF receiver against the OOB OFDM-blocker-induced IM2 distortion and, thus, improve the robustness of the biomedical devices in harsh wireless environments in the MedRadio and UHF bands.


Assuntos
Amplificadores Eletrônicos , Processamento de Sinais Assistido por Computador , Desenho de Equipamento , Óxidos , Semicondutores
4.
Artigo em Inglês | MEDLINE | ID: mdl-34457042

RESUMO

The use of graphene quantum dots as biomedical device and drug delivery system has been increasing. This nanoplatform of pure carbon has showed unique properties and showed to be safe for human use. The imatinib is a molecule designed to specifically inhibit the tyrosine kinase, used for leukemia treatment. In this study, we successfully decorated the graphene quantum dots (GQDs@imatinb) by a carbodiimide crosslinking reaction. The GQDs@imatinb were characterized by FTIR and AFM. The nanoparticles' in vitro behaviors were evaluated by cellular trafficking (internalization) assay and cell viability and apoptosis assays in various cancer cell lines, including suspension (leukemia) cells and adherent cancer cells. The results showed that the incorporation of the imatinib on the surface of the graphene quantum dots did not change the nanoparticles' morphology and properties. The GQDs@imatinb could be efficiently internalized and kill cancer cells via the induction of apoptosis. The data indicated that the prepared GQDs@imatinb might be a great drug nano-platform for cancer, particularly leukemia treatments.

5.
Mar Drugs ; 18(8)2020 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-32796603

RESUMO

Scaffold material is essential in providing mechanical support to tissue, allowing stem cells to improve their function in the healing and repair of trauma sites and tissue regeneration. The scaffold aids cell organization in the damaged tissue. It serves and allows bio mimicking the mechanical and biological properties of the target tissue and facilitates cell proliferation and differentiation at the regeneration site. In this study, the developed and assayed bio-composite made of unique collagen fibers and alginate hydrogel supports the function of cells around the implanted material. We used an in vivo rat model to study the scaffold effects when transplanted subcutaneously and as an augment for tendon repair. Animals' well-being was measured by their weight and daily activity post scaffold transplantation during their recovery. At the end of the experiment, the bio-composite was histologically examined, and the surrounding tissues around the implant were evaluated for inflammation reaction and scarring tissue. In the histology, the formation of granulation tissue and fibroblasts that were part of the inclusion process of the implanted material were noted. At the transplanted sites, inflammatory cells, such as plasma cells, macrophages, and giant cells, were also observed as expected at this time point post transplantation. This study demonstrated not only the collagen-alginate device biocompatibility, with no cytotoxic effects on the analyzed rats, but also that the 3D structure enables cell migration and new blood vessel formation needed for tissue repair. Overall, the results of the current study proved for the first time that the implantable scaffold for long-term confirms the well-being of these rats and is correspondence to biocompatibility ISO standards and can be further developed for medical devices application.


Assuntos
Antozoários/química , Materiais Biocompatíveis , Colágenos Fibrilares/química , Implantes Experimentais , Procedimentos Ortopédicos/instrumentação , Lesões do Manguito Rotador/cirurgia , Manguito Rotador/cirurgia , Alicerces Teciduais , Alginatos/química , Animais , Materiais Biocompatíveis/toxicidade , Modelos Animais de Doenças , Colágenos Fibrilares/isolamento & purificação , Colágenos Fibrilares/toxicidade , Reação a Corpo Estranho/etiologia , Reação a Corpo Estranho/patologia , Hidrogéis , Implantes Experimentais/efeitos adversos , Masculino , Procedimentos Ortopédicos/efeitos adversos , Desenho de Prótese , Ratos Wistar , Manguito Rotador/patologia , Lesões do Manguito Rotador/patologia , Fatores de Tempo , Alicerces Teciduais/efeitos adversos , Cicatrização
6.
Acta Neurochir Suppl ; 126: 85-88, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29492538

RESUMO

OBJECTIVE: The monitoring of intracranial pressure (ICP) is indicated for diagnosing and guiding therapy in many neurological conditions. Current monitoring methods, however, are highly invasive, limiting their use to the most critically ill patients only. Our goal is to develop and test an embedded device that performs all necessary mathematical operations in real-time for noninvasive ICP (nICP) estimation based on a previously developed model-based approach that uses cerebral blood flow velocity (CBFV) and arterial blood pressure (ABP) waveforms. MATERIALS AND METHODS: The nICP estimation algorithm along with the required preprocessing steps were implemented on an NXP LPC4337 microcontroller unit (MCU). A prototype device using the MCU was also developed, complete with display, recording functionality, and peripheral interfaces for ABP and CBFV monitoring hardware. RESULTS: The device produces an estimate of mean ICP once per minute and performs the necessary computations in 410 ms, on average. Real-time nICP estimates differed from the original batch-mode MATLAB implementation of theestimation algorithm by 0.63 mmHg (root-mean-square error). CONCLUSIONS: We have demonstrated that real-time nICP estimation is possible on a microprocessor platform, which offers the advantages of low cost, small size, and product modularity over a general-purpose computer. These attributes take a step toward the goal of real-time nICP estimation at the patient's bedside in a variety of clinical settings.


Assuntos
Algoritmos , Pressão Arterial/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Circulação Cerebrovascular/fisiologia , Equipamentos e Provisões , Hipertensão Intracraniana/diagnóstico , Pressão Intracraniana/fisiologia , Humanos , Monitorização Fisiológica/instrumentação
7.
Molecules ; 22(2)2017 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-28208680

RESUMO

The microbial contamination in food packaging has been a major concern that has paved the way to search for novel, natural anti-microbial agents, such as modified α-mangostin. In the present study, twelve synthetic analogs were obtained through semi-synthetic modification of α-mangostin by Ritter reaction, reduction by palladium-carbon (Pd-C), alkylation, and acetylation. The evaluation of the anti-microbial potential of the synthetic analogs showed higher bactericidal activity than the parent molecule. The anti-microbial studies proved that I E showed high anti-bacterial activity whereas I I showed the highest anti-fungal activity. Due to their microbicidal potential, modified α-mangostin derivatives could be utilized as active anti-microbial agents in materials for the biomedical and food industry.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Garcinia mangostana/química , Xantonas/química , Xantonas/farmacologia , Bactérias/efeitos dos fármacos , Fungos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Xantonas/síntese química , Xantonas/isolamento & purificação
8.
J Med Syst ; 42(1): 22, 2017 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-29242996

RESUMO

Rural India lacks easy access to health practitioners and medical centers, depending instead on community health workers. In these areas, common ailments that are easy to manage with medicines, often lead to medical escalations and even fatalities due to lack of awareness and delayed diagnosis. The introduction of wearable health devices has made it easier to monitor health conditions and to connect doctors and patients in urban areas. However, existing initiatives have not succeeded in providing adequate health monitoring to rural and low-literate patients, as current methods are expensive, require consistent connectivity and expect literate users. Our design considerations address these concerns by providing low-cost medical devices connected to a low-cost health platform, along with personalized guidance based on patient physiological parameters in local languages, and alerts to medical practitioners in case of emergencies. This patient-centric integrated healthcare system is designed to manage the overall health of villagers with real-time health monitoring of patients, to offer guidance on preventive care, and to increase health awareness and self-monitoring at an affordable price. This personalized health monitoring system addresses the health-related needs in remote and rural areas by (1) empowering health workers in monitoring of basic health conditions for rural patients in order to prevent escalations, (2) personalized feedback regarding nutrition, exercise, diet, preventive Ayurveda care and yoga postures based on vital parameters and (3) reporting of patient data to the patient's health center with emergency alerts to doctor and patient. The system supports community health workers in the diagnostic procedure, management, and reporting of rural patients, and functions well even with only intermittent access to Internet.


Assuntos
Internet , Monitorização Ambulatorial/métodos , Assistência Centrada no Paciente/métodos , População Rural , Computação em Nuvem , Dieta , Exercício Físico , Humanos , Índia , Ayurveda , Tecnologia de Sensoriamento Remoto , Yoga
9.
Biomed Microdevices ; 18(3): 45, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27194027

RESUMO

Olfactory ensheathing cells (OECs) are primary candidates for cell transplantation therapy to repair spinal cord injury (SCI). However, the post transplantation survival of these cells remains a major hurdle for a success using this therapy. Mechanical stimuli may contribute to the maintenance of these cells and thus, mechanotransduction studies of OECs may serve as a key benefit to identify strategies for improvement in cell transplantation. We developed an electromagnetic cell stretching device based on a single sided uniaxial stretching approach to apply tensile strain to OECs in culture. This paper reports the design, simulation and characterisation of the stretching device with preliminary experimental observations of OECs in vitro. The strain field of the deformable membrane was investigated both experimentally and numerically. Heterogeneity of the device provided an ideal platform for establishing strain requirement for the OEC culture. The cell stretching system developed may serve as a tool in exploring the mechanobiology of OECs for future SCI transplantation research.


Assuntos
Mecanotransdução Celular , Bulbo Olfatório/citologia , Transplante de Células , Células Cultivadas , Fenômenos Eletromagnéticos , Desenho de Equipamento , Análise de Elementos Finitos , Humanos , Traumatismos da Medula Espinal/terapia
10.
Life (Basel) ; 14(1)2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38255755

RESUMO

Consideration of the individual carpal bone characteristics of the wrist plays a key role in well-functioning biomedical devices and successful surgical procedures. Although geometric differences and individual bone sizes have been analyzed in the literature, detailed morphologic descriptions and correlations covering the entire wrist reported in a clinical context are lacking. This study aimed to perform a comprehensive and automatic analysis of the wrist morphology using the freely available "Open Source Carpal Database" (OSCD). We quantified the size of each of the individual carpal bones and their combination. These sizes were extracted in n = 117 datasets of the wrist of the OSCD in anatomical directions and analyzed using descriptive statics and correlation analysis to investigate the morphological characteristics under sex-specific aspects and to provide regression plots and equations to predict individual carpal bone sizes from the proximal and distal row dimensions. The correlations in the proximal row were higher compared to the distal row. We established comprehensive size correlations and size rations and found that there exist statistical differences between sex, particularly of the scaphoid. The regression plots and equations we provided will assist surgeons in a more accurate preoperative morphological evaluation for therapy planning and may be used for future anatomically inspired orthopedic biomedical device designs.

11.
Med Eng Phys ; 125: 104127, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38508804

RESUMO

The monitoring of the neuromuscular blockade is critical for patient's safety during and after surgery. The monitoring of neuromuscular blockade often requires the use of Train of Four (TOF) technique. During a TOF test two electrodes are attached to the ulnar nerve, and a series of four electric pulses are applied. The electrical stimulation causes the thumb to twitch, and the amount of twitch varies depending on the amount of neuromuscular blockade in patient's system. Current medical devices used to assist anesthesiologists to perform TOF monitoring often require free hand movement and do not provide accurate or reliable results. The goal of this work is to design, prototype and test a new medical device that provides reliable TOF results when thumb movement is restricted. A medical device that uses a pressurized catheter balloon to detect the response thumb twitch of the TOF test is created. An analytical model, numerical study, and mechanical finger testing were employed to create an optimum design. The design is tested through a pilot human subjects study. No significant correlation is reported with subjects' properties, including hand size.


Assuntos
Bloqueio Neuromuscular , Fármacos Neuromusculares não Despolarizantes , Humanos , Monitoração Neuromuscular/métodos , Nervo Ulnar/fisiologia , Estimulação Elétrica
12.
Nanomicro Lett ; 16(1): 102, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38300387

RESUMO

Substrates or encapsulants in soft and stretchable formats are key components for transient, bioresorbable electronic systems; however, elastomeric polymers with desired mechanical and biochemical properties are very limited compared to non-transient counterparts. Here, we introduce a bioresorbable elastomer, poly(glycolide-co-ε-caprolactone) (PGCL), that contains excellent material properties including high elongation-at-break (< 1300%), resilience and toughness, and tunable dissolution behaviors. Exploitation of PGCLs as polymer matrices, in combination with conducing polymers, yields stretchable, conductive composites for degradable interconnects, sensors, and actuators, which can reliably function under external strains. Integration of device components with wireless modules demonstrates elastic, transient electronic suture system with on-demand drug delivery for rapid recovery of post-surgical wounds in soft, time-dynamic tissues.

13.
Adv Mater ; 36(25): e2311020, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38511489

RESUMO

Color-tunable organic light-emitting diodes (CT-OLEDs) have a large color-tuning range, high efficiency and operational stability at practical luminance, making them ideal for human-machine interactive terminals of wearable biomedical devices. However, the device operational lifetime of CT-OLEDs is currently far from reaching practical requirements. To address this problem, a tetradentate Pt(II) complex named tetra-Pt-dbf, which can emit efficiently in both monomer and aggregation states, is designed. This emitter has high Td of 508 °C and large intermolecular bonding energy of -52.0 kcal mol⁻1, which improve its thermal/chemical stability. This unique single-emitter CT-OLED essentially avoids the "color-aging issue" and achieves a large color-tuning span (red to yellowish green) and a high external quantum efficiency (EQE) of ≈30% at 1000 cd m-2 as well as an EQE of above 25% at 10000 cd m-2. A superior LT90 operational lifetime of 520,536 h at a functional luminance of 100 cd m-2, which is over 20 times longer than the state-of-the-art CT-OLEDs, is estimated. To demonstrate the potential application of such OLEDs in wearable biomedical devices, a simple electromyography (EMG)-visualization system is fabricated using the CT-OLEDs.

14.
Biomed Phys Eng Express ; 10(3)2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38447224

RESUMO

This article describes the development of a system forin vivomeasurements of lead body burden in mice using109Cd K x-ray fluorescence (XRF). This K XRF system could facilitate early-stage studies on interventions that ameliorate or reverse organ tissue damage from lead poisoning by reducing animal numbers through a cross-sectional study approach. A novel mouse phantom was developed based on a mouse atlas and 3D-printed using PLA plastic with plaster of Paris 'bone' inserts. PLA plastic was found to be a good surrogate for soft tissue in XRF measurements and the phantoms were found to be good models of mice. As expected, lead detection limits varied with mouse size, mouse orientation, and mouse position with respect to the source and detector. The work suggests that detection limits of 10 to 20µg Pb per g bone mineral may be possible for a 2 to 3 hour XRF measurement in a single animal, an adequate limit for some pre-clinical studies. The109Cd K XRF mouse measurement system was also modeled using the Monte Carlo code MCNP. The combination of experiment and modeling found that contrary to expectation, accurate measurements of lead levels in mice required calibration using mouse-specific calibration standards due to the coherent scatter peak normalization failing when small animals are measured. MCNP modeling determined that this was because the coherent scatter signal from soft tissue, which until now has been assumed negligible, becomes significant when compared to the coherent scatter signal in bone in small animals. This may have implications for some human measurements. This work suggests that109Cd K x-ray fluorescence measurements of lead body burden are precise enough to make the system feasible for small animals if appropriately calibrated. Further work to validate the technology's measurement accuracy and performancein vivowill be required.


Assuntos
Cádmio , Chumbo , Animais , Humanos , Camundongos , Raios X , Chumbo/análise , Espectrometria por Raios X/métodos , Estudos de Viabilidade , Estudos Transversais , Impressão Tridimensional , Poliésteres
15.
Med Biol Eng Comput ; 62(4): 1153-1163, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38158548

RESUMO

Capsule endoscopy offers a non-invasive and patient-friendly method for imaging the gastrointestinal tract, boasting superior tissue accessibility compared to traditional endoscopy and colonoscopy. While advances have led to capsules capable of drug delivery, tactile sensing, and biopsy, size constraints often limit a single capsule from having multifunctionality. In response, we introduce multi-capsule endoscopy, where individually ingested capsules, each with unique functionalities, work collaboratively. However, synchronized navigation of these capsules is essential for this approach. In this paper, we present an active distance control strategy using a closed-loop system. This entails equipping one capsule with a sphere permanent magnet and the other with a solenoid. We utilized a Simulink model, incorporating (i) the peristalsis motion on the primary capsule, (ii) a PID controller, (iii) force dynamics between capsules through magnetic dipole approximation, and (iv) position tracking of the secondary capsule. For practical implementation, Hall effect sensors determined the inter-capsule distance, and a PID controller adjusted the solenoid's current to maintain the desired capsule spacing. Our proof-of-concept experiments, conducted on phantoms and ex vivo bovine tissues, pulled the leading capsule mimicking a typical human peristalsis speed of 1 cm/min. Results showcased an inter-capsule distance of 1.94 mm ± 0.097 mm for radii of curvature at 500 mm, 250 mm, and 100 mm, aiming for a 2-mm capsule spacing. For ex vivo bovine tissue, the achieved distance was 0.97 ± 0.28 mm against a target inter-capsule distance of 1 mm. Through the successful demonstration of precise inter-capsule control, this study paves the way for the potential of multi-capsule endoscopy in future research.


Assuntos
Endoscopia por Cápsula , Animais , Bovinos , Humanos , Endoscopia por Cápsula/métodos , Trato Gastrointestinal/fisiologia , Fenômenos Eletromagnéticos , Fenômenos Mecânicos , Movimento (Física)
16.
Micromachines (Basel) ; 14(8)2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37630073

RESUMO

Cellular response to mechanical stimuli is a crucial factor for maintaining cell homeostasis. The interaction between the extracellular matrix and mechanical stress plays a significant role in organizing the cytoskeleton and aligning cells. Tools that apply mechanical forces to cells and tissues, as well as those capable of measuring the mechanical properties of biological cells, have greatly contributed to our understanding of fundamental mechanobiology. These tools have been extensively employed to unveil the substantial influence of mechanical cues on the development and progression of various diseases. In this report, we present an economical and high-performance uniaxial cell stretching device. This paper reports the detailed operation concept of the device, experimental design, and characterization. The device was tested with MDA-MB-231 breast cancer cells. The experimental results agree well with previously documented morphological changes resulting from stretching forces on cancer cells. Remarkably, our new device demonstrates comparable cellular changes within 30 min compared with the previous 2 h stretching duration. This third-generation device significantly improved the stretching capabilities compared with its previous counterparts, resulting in a remarkable reduction in stretching time and a substantial increase in overall efficiency. Moreover, the device design incorporates an open-source software interface, facilitating convenient parameter adjustments such as strain, stretching speed, frequency, and duration. Its versatility enables seamless integration with various optical microscopes, thereby yielding novel insights into the realm of mechanobiology.

17.
Colloids Surf B Biointerfaces ; 221: 113024, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36403418

RESUMO

Microbial adhesion and formation of biofilms cause a serious problem in several areas including but not limited to food spoilage, industrial corrosion and nosocomial infections. These microbial biofilms pose a serious threat to human health since microbial communities in the biofilm matrix are protected with exopolymeric substances and difficult to eradicate with antibiotics. Hence, the prevention of microbial adhesion followed by biofilm formation is one of the promising strategies to prevent these consequences. The attachment of antimicrobial agents, coatings of nanomaterials and synthesis of hybrid materials are widely used approach to develop surfaces having potential to hinder bacterial adhesion and biofilm formation. In this study, epigallocatechin gallate (EGCG) is attached on p(HEMA-co-GMA) membranes to prevent the bacterial colonization. The attachment of EGCG to membranes was proved by Fourier-transform infrared spectroscopy (FT-IR). The synthesized membrane showed porous structure (SEM), and desirable swelling degree, which are ideal when it comes to the application in biotechnology and biomedicine. Furthermore, EGCG attached membrane showed significant potential to prevent the microbial colonization on the surface. The obtained results suggest that EGCG attached polymer could be used as an alternative approach to prevent the microbial colonization on the biomedical surfaces, food processing equipment as well as development of microbial resistant food packaging systems.


Assuntos
Aderência Bacteriana , Biofilmes , Humanos , Espectroscopia de Infravermelho com Transformada de Fourier , Polímeros
18.
Comput Biol Med ; 166: 107525, 2023 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-37778216

RESUMO

A stent implantation is a standard medical procedure for treating coronary artery diseases. Over the years, various different designs have been explored for the stents which come with a range of limitations, including late in-stent restenosis (due to low radial strength), foreshortening, radial recoil, etc. Contrary, stents with auxetic design, characterized by a negative Poisson's ratio, display unique deformation characteristics that result in enhanced mechanical properties in terms of its radial strength, radial recoil, foreshortening, and more. In this study, we have analysed a novel double arrowhead (DA) auxetic stent that aims to overcome the limitations associated with traditional stents, specifically in terms of radial strength, foreshortening, and radial recoil. The parametric analysis was done initially on the DA's unit ring structure to optimize the design by evaluating the effect of three design parameters (angle, amplitude, and width) on the mechanical characteristics (radial strength and radial recoil) using finite element analysis. The width of the strut was found to be the primary determinant of the stent structure's properties. Consequently, the angle and width were found to have the least effect on altering the stent's mechanical properties. After performing the parametric analysis, optimal design factors were selected to design the full-length DA auxetic stent. The mechanical characteristics of the DA auxetic stent were assessed and compared in a case study with the Cypher™ commercial stent. The radial strength of DA auxetic stent was found to be 7.26 N/mm, which is more than double the Cypher™ commercial stent's radial strength. Additionally, the proposed stent possesses reduced radial recoil property and completely eliminates the stent foreshortening issue, which shows the superior mechanical properties of the proposed auxetic stent and its potential as a promising candidate for future stent designs.

19.
Micromachines (Basel) ; 14(1)2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36677193

RESUMO

The mechanisms of deep-hole microdrilling of pure Mg material were experimentally studied in order to find a suitable setup for a novel intraocular drug delivery device prototyping. Microdrilling tests were performed with 0.20 mm and 0.35 mm microdrills, using a full factorial design in which cutting speed vc and feed fz were varied over two levels. In a preliminary phase, the chip shape was evaluated for low feeds per tooth down to 1 µm, to verify that the chosen parameters were appropriate for machining. Subsequently, microdrilling experiments were carried out, in which diameter, burr height and surface roughness of the drilled holes were examined. The results showed that the burr height is not uniform along the circumference of the holes. In particular, the maximum burr height increases with higher cutting speed, due to the thermal effect that plasticizes Mg. Hole entrance diameters are larger than the nominal tool diameters due to tool runout, and their values are higher for high vc and fz. In addition, the roughness of the inner surface of the holes increases as fz increases.

20.
Biomater Res ; 27(1): 14, 2023 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-36800989

RESUMO

BACKGROUND: The wound healing process is a complex cascade of physiological events, which are vulnerable to both our body status and external factors and whose impairment could lead to chronic wounds or wound healing impediments. Conventional wound healing materials are widely used in clinical management, however, they do not usually prevent wounds from being infected by bacteria or viruses. Therefore, simultaneous wound status monitoring and prevention of microbial infection are required to promote healing in clinical wound management. METHODS: Basic amino acid-modified surfaces were fabricated in a water-based process via a peptide coupling reaction. Specimens were analyzed and characterized by X-ray photoelectron spectroscopy, Kelvin probe force microscopy, atomic force microscopy, contact angle, and molecular electrostatic potential via Gaussian 09. Antimicrobial and biofilm inhibition tests were conducted on Escherichia coli and Staphylococcus epidermidis. Biocompatibility was determined through cytotoxicity tests on human epithelial keratinocytes and human dermal fibroblasts. Wound healing efficacy was confirmed by mouse wound healing and cell staining tests. Workability of the pH sensor on basic amino acid-modified surfaces was evaluated on normal human skin and Staphylococcus epidermidis suspension, and in vivo conditions. RESULTS: Basic amino acids (lysine and arginine) have pH-dependent zwitterionic functional groups. The basic amino acid-modified surfaces had antifouling and antimicrobial properties similar to those of cationic antimicrobial peptides because zwitterionic functional groups have intrinsic cationic amphiphilic characteristics. Compared with untreated polyimide and modified anionic acid (leucine), basic amino acid-modified polyimide surfaces displayed excellent bactericidal, antifouling (reduction ~ 99.6%) and biofilm inhibition performance. The basic amino acid-modified polyimide surfaces also exhibited wound healing efficacy and excellent biocompatibility, confirmed by cytotoxicity and ICR mouse wound healing tests. The basic amino acid-modified surface-based pH monitoring sensor was workable (sensitivity 20 mV pH-1) under various pH and bacterial contamination conditions. CONCLUSION: Here, we developed a biocompatible and pH-monitorable wound healing dressing with antimicrobial activity via basic amino acid-mediated surface modification, creating cationic amphiphilic surfaces. Basic amino acid-modified polyimide is promising for monitoring wounds, protecting them from microbial infection, and promoting their healing. Our findings are expected to contribute to wound management and could be expanded to various wearable healthcare devices for clinical, biomedical, and healthcare applications.

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