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1.
Artigo em Inglês | MEDLINE | ID: mdl-34793117

RESUMO

Patch-type drug delivery has garnered increased attention as an attractive alternative to the existing drug delivery techniques. Thus far, needle phobia and efficient drug delivery remain huge challenges. To address the issue of needle phobia and enhance drug delivery, we developed a needle-free and self-adhesive microcup patch that can be loaded with an ultrathin salmon DNA (SDNA) drug carrier film. This physically integrated system can facilitate efficient skin penetration of drugs loaded into the microcup patch. The system consists of three main components, namely, a cup that acts as a drug reservoir, an adhesive system that attaches the patch to the skin, and physical stimulants that can be used to increase the efficiency of drug delivery. In addition, an ultrathin SDNA/drug film allows the retention of the drug in the cup and its efficient release by dissolution in the presence of moisture. This latter feature has been validated using gelatin as a skin mimic. The cup design itself has been validated by comparing its deformation and displacement with those of a cylindrical structure. Integration of the self-adhesive microcup patch with both ultrasonic waves and an electric current allows the model drug to penetrate the stratum corneum of the skin barrier and the whole epidermis, thereby enhancing transdermal drug delivery and reducing skin irritation. This system can be used as a wearable biomedical device for efficient transdermal and needle-free drug delivery.

2.
Adv Sci (Weinh) ; 8(19): e2100725, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34351701

RESUMO

A radiofrequency ablation (RFA) needle integrated with a temperature sensor (T-sensor) and pressure sensor (P-sensor) is designed and utilized for real-time internal steam pop monitoring during RFA. The characteristics of the sensor-integrated RFA needle (sRFA-needle) are investigated quantitatively using a pressure chamber system, and the feasibility and usability of the needle in preclinical and clinical trials is demonstrated. The sharp changes in the temperature and normalized pressure sensor signals induced by the abrupt release of hot and high-pressure steam can be clearly monitored during the steam pop phenomena. The basic mechanism of the preliminary steam pop is hypothesized and verified using in situ ultrasound imaging data and computational analysis data of the RFA procedure. Moreover, the usability of the system in clinical trials is investigated, and the steam pop phenomena during the RFA procedure are detected using T-sensor and P-sensor. The results confirm that the sensor integration on the medical needle can provide critical data for safer and more effective medical practices.

3.
ACS Appl Mater Interfaces ; 13(29): 35069-35078, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34282875

RESUMO

Many conventional micropatterning and nanopatterning techniques employ toxic chemicals, rendering them nonbiocompatible and unsuited for biodevice production. Herein the formation of water bridges on the surface of hyaluronic acid (HA) films is exploited to develop a transfer-based nanopatterning method applicable to diverse structures and materials. The HA film surface, made deformable via water bridge generation, is brought into contact with a functional material and subjected to thermal treatment, which results in film shrinkage, allowing a robust pattern transfer. The proposed biocompatible method, which avoids the use of extra chemicals, enables the transfer of nanoscale, microscale, and thin-film structures as well as functional materials such as metals and metal oxides. A nanopatterned HA film is transferred onto a moisture-containing contact lens to fabricate smart contact lenses with unique optical characteristics of rationally designed optical nanopatterns. These lenses demonstrated binocular parallax-induced stereoscopy via nanoline array polarization and acted as cutoff filters, with nanodot arrays, capable of treating Irlen syndrome.


Assuntos
Materiais Biocompatíveis/química , Lentes de Contato , Ácido Hialurônico/química , Impressão , Materiais Inteligentes/química , Água/química , Percepção de Profundidade , Nanoestruturas/química , Poliuretanos/química , Prata/química
4.
Adv Healthc Mater ; 10(9): e2001461, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33694309

RESUMO

Conventional flexible pressure sensors are not suitable for high-pressure applications due to their low saturation pressure. In this study, an ultra-wide range pressure sensor is designed based on the optimized microstructure of the polyimide/carbon nanotubes (PI/CNT) nanocomposite film. The sensing range of the pressure sensor is expanded by adopting polyimide (PI) with a high elastic modulus as a matrix material and its sensitivity is improved through functional sensing film with tip-flattened microdome arrays. As a result, the pressure sensor can measure a wide pressure range (≈ 0-3000 kPa) and possesses the sensitivity of ≈ 5.66 × 10-3 -0.23 × 10-3 kPa-1 with high reliability and durability up to 1000 cycles. The proposed sensor is integrated into the hand and foot pressure monitoring systems for workout monitoring. The representative values of the pressure distribution in the hands and feet during the powerlifting are acquired and analyzed through Pearson's correlation coefficient (PCC). The analyzed results suggest that the pressure sensor can provide useful real-time information for healthcare and sports performance monitoring.


Assuntos
Nanocompostos , Nanotubos de Carbono , Dispositivos Eletrônicos Vestíveis , Pressão , Reprodutibilidade dos Testes
5.
ACS Nano ; 15(1): 503-514, 2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33439612

RESUMO

The fabrication of large-area and flexible nanostructures currently presents various challenges related to the special requirements for 3D multilayer nanostructures, ultrasmall nanogaps, and size-controlled nanomeshes. To overcome these rigorous challenges, a simple method for fabricating wafer-scale, ultrasmall nanogaps on a flexible substrate using a temperature above the glass transition temperature (Tg) of the substrate and by layer-by-layer nanoimprinting is proposed here. The size of the nanogaps can be easily controlled by adjusting the pressure, heating time, and heating temperature. In addition, 3D multilayer nanostructures and nanocomposites with 2, 3, 5, 7, and 20 layers were fabricated using this method. The fabricated nanogaps with sizes ranging from approximately 1 to 40 nm were observed via high-resolution transmission electron microscopy (HRTEM). The multilayered nanostructures were evaluated using focused ion beam (FIB) technology. Compared with conventional methods, our method could not only easily control the size of the nanogaps on the flexible large-area substrate but could also achieve fast, simple, and cost-effective fabrication of 3D multilayer nanostructures and nanocomposites without any post-treatment. Moreover, a transparent electrode and nanoheater were fabricated and evaluated. Finally, surface-enhanced Raman scattering substrates with different nanogaps were evaluated using rhodamine 6G. In conclusion, it is believed that the proposed method can solve the problems related to the high requirements of nanofabrication and can be applied in the detection of small molecules and for manufacturing flexible electronics and soft actuators.

6.
ACS Appl Mater Interfaces ; 13(2): 3358-3368, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33347263

RESUMO

A novel method for fabricating shape-controlled and well-arrayed heterogeneous nanostructures by altering the melting point of the metal thin film at the nanoscale is proposed. Silver nanofilms (AgNFs) are transformed into silver nanoislands (AgNIs), silver nanoparticles (AgNPs), and silver nanogaps (AgNGs) that are well-ordered and repositioned inside the gold nanoholes (AuNHs) depending on the diameter of the AuNHs, the thickness of the AgNF, and the heating temperature (120-200 °C). This method demonstrates the ability to fabricate uniform, stable, and unique structures with a fast, simple, and mass-producible process. For demonstrating the diverse applicability of the developed structures, high-density AgNGs inside the AuNHs are utilized as surface-enhanced Raman spectroscopy (SERS) substrates. These AgNGs-based SERS substrates exhibit a performance enhancement, which is 1.06 × 106 times greater than that of a metal film, with a relative standard deviation of 19.8%. The developed AgNP/AgNI structures are also used as nonreproducible anti-counterfeiting signs, and the anti-counterfeiting/readout system is demonstrated via image processing. Therefore, our method could play a vital role in the nanofabrication of high-demand nanostructures.

7.
ACS Nano ; 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33263256

RESUMO

This study proposes a reliable and self-powered hydrogen (H2) gas sensor composed of a chemo-mechanically operating nanostructured film and photovoltaic cell. Specifically, the nanostructured film has a configuration in which an asymmetrically coated palladium (Pd) film is coated on a periodic polyurethane acrylate (PUA) nanograting. The asymmetric Pd nanostructures, optimized by a finite element method simulation, swell upon reacting with H2 and thereby bend the PUA nanograting, changing the amount of transmitted light and the current output of the photovoltaic cell. Since the degree of warping is determined by the concentration of H2 gas, a wide concentration range of H2 (0.1-4.0%) can be detected by measuring the self-generated electrical current of the photovoltaic cell without external power. The normalized output current changes are ∼1.5%, ∼2.8%, ∼3.5%, ∼5.0%, ∼21.5%, and 25.3% when the concentrations of H2 gas are 0.1%, 0.5%, 1.0%, 1.6%, 2%, and 4%, respectively. Moreover, because Pd is highly chemically reactive to H2 and also because there is no electrical current applied through Pd, the proposed sensor can avoid device failure due to the breakage of the Pd sensing material, resulting in high reliability, and can show high selectivity against various gases such as carbon monoxide, hydrogen sulfide, nitrogen dioxide, and water vapor. Finally, using only ambient visible light, the sensor was modularized to produce an alarm in the presence of H2 gas, verifying a potential always-on H2 gas monitoring application.

10.
ACS Sens ; 5(2): 481-489, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-32020796

RESUMO

In this research, an ultrathin, biocompatible, and flexible pressure sensor with a wide pressure range has been developed and applied in biomedical applications. The pressure sensing mechanism is based on the variation of contact resistance between an electrode and a three-dimensional microstructured polyimide/carbon nanotube composite film. The sensor has a thickness of about 31.3 µm, a maximum sensitivity of 41.0 MPa-1, and a sensing range of 10-500 kPa. Moreover, in situ temperature measurement by an integrated resistive temperature detector enables data correction for varying temperature conditions. In order to show the advantages of the fabricated sensor, it is attached to the human body and integrated with the surface of a radiofrequency ablation (RFA) needle with small radius of curvature. In the experiments, the proposed pressure sensor measured subtle pressure levels (pulse pressure) and high pressure levels (fingertip pressure) without losing conformal contact with the skin. In addition, when the pressure-sensor-integrated RFA needle was inserted into a bovine liver, successful detection of steam popping phenomenon was observed.


Assuntos
Técnicas Biossensoriais/métodos , Humanos
11.
ACS Sens ; 5(5): 1363-1373, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32105060

RESUMO

In vivo sensing of various physical/chemical parameters is gaining increased attention for early prediction and management of various diseases. However, there are major limitations on the fabrication method of multiparameter needle-based in vivo sensing devices, particularly concerning the uniformity between sensors. To address these challenges, we developed a microscale biosensor array for the measurement of electrical conductivity, pH, glucose, and lactate concentrations on a flexible polymeric polyimide platform with electrodeposited electrochemically active layers. The biosensor array was then transferred to a medical needle toward multiparametric in vivo sensing. The flexibility of the sensor platform allowed an easy integration to the curved surface (φ = 1.2 mm) of the needle. Furthermore, the electrodeposition process was used to localize various active materials for corresponding electrochemical sensors on the microscale electrodes with a high precision (patterning area = 150 µm × 2 mm). The biosensor array-modified needle was aimed to discriminate cancer from normal tissues by providing real-time discrimination of glucose, lactate concentration, pH, and electrical conductivity changes associated with the cancer-specific metabolic processes. The sensor performance was thus evaluated using solution samples, covering the physiological concentrations for cancer discrimination. Finally, the possibility of in vivo electrochemical biosensing during needle insertion was confirmed by utilizing the needle in a hydrogel phantom that mimicked the normal and cancer microenvironments.


Assuntos
Técnicas Biossensoriais , Eletrodos , Glucose , Agulhas , Polímeros
12.
ACS Nano ; 14(2): 2191-2201, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-31990171

RESUMO

The growing interest in wearable devices has drawn increased attention to smart textiles, and various transfer methods have therefore been introduced to realize the desired functions using textiles as substrates. However, the existing transfer techniques are not suited for the production of sophisticated nanoscale patterns on textiles, as textile roughness and difficulty of precise pattern size control hinder miniaturization, deteriorate device performance, and complicate the use of optical phenomena such as surface plasmon resonance. To address these limitations, we have developed a method based on simple dissolution of a water-soluble nanopatterned polymer film for the facile transfer of nanostructures of on-film-deposited functional materials onto textile substrates. The above method tolerates a variety of functional materials, e.g., metals and SiO2, and nano/microscale structures, e.g., nanoscale lines, dots, holes, and mesh patterns with a minimum pattern width of 50 nm. The proposed technique is employed to fabricate a palladium nanoscale line array (utilized as a highly sensitive and selective hydrogen sensor) and is shown to be suitable for the production of security patterns on textiles, as it allows the printing of complex nanostructure patterns with electrical and optical functionalities.

13.
Biosens Bioelectron ; 148: 111822, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31698304

RESUMO

A biopsy needle integrated with a multi-modal physical/chemical sensor array for electrical conductivity, pH, and glucose concentration measurement was developed. A flexible device with an electrical conductivity sensor, a pH sensor, and a glucose sensor was fabricated on a flexible polyimide substrate with thickness less than 20 µm. Then, the sensor was directly integrated onto the surface of biopsy needle by attaching with a pressure sensitive adhesive. The performance factors of the sensor were examined, showing that it could properly measure the parameters in the ranges of human body conditions (conductivity = 0.0265 S/m - 1.027 S/m, pH = 6.6-7.4, and glucose concentration = 2 mM-13 mM). The capabilities of dual-modal and multi-modal sensing were demonstrated by tests with a liver cancer mimicking hydrogel phantom, a solution sample, and porcine liver tissue with exchanged parameters by perfusion of the phosphate buffer saline. Based on these results, we expect that the biopsy needle integrated with the multi-modal sensor array could help to increase the accuracy of the image-guided biopsy process by providing the information of tissue types at the needle tip.


Assuntos
Biópsia/instrumentação , Técnicas Biossensoriais/instrumentação , Animais , Condutividade Elétrica , Desenho de Equipamento , Glucose/análise , Humanos , Concentração de Íons de Hidrogênio , Agulhas , Suínos
14.
ACS Appl Mater Interfaces ; 12(1): 1698-1706, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31825585

RESUMO

Wearable pressure sensors have been attracting great attention for a variety of practical applications, including electronic skin, smart textiles, and healthcare devices. However, it is still challenging to realize wearable pressure sensors with sufficient sensitivity and low hysteresis under small mechanical stimuli. Herein, we introduce simple, cost-effective, and sensitive capacitive pressure sensor based on porous Ecoflex-multiwalled carbon nanotube composite (PEMC) structures, which leads to enhancing the sensitivity (6.42 and 1.72 kPa-1 in a range of 0-2 and 2-10 kPa, respectively) due to a synergetic effect of the porous elastomer and percolation of carbon nanotube fillers. The PEMC structure shows excellent mechanical deformability and compliance for an effective integration with practical wearable devices. Also, the PEMC-based pressure sensor shows not only the long-term stability, low-hysteresis, and fast response under dynamic loading but also the high robustness against temperature and humidity changes. Finally, we demonstrate a prosthetic robot finger integrated with a PEMC-based pressure sensor and an actuator as well as a healthcare wristband capable of continuously monitoring blood pressure and heart rate.


Assuntos
Técnicas Biossensoriais , Determinação da Pressão Arterial/instrumentação , Monitorização Fisiológica , Nanotubos de Carbono/química , Elastômeros/química , Humanos , Fenômenos Mecânicos , Porosidade , Têxteis , Dispositivos Eletrônicos Vestíveis
15.
Adv Healthc Mater ; 8(22): e1900978, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31596545

RESUMO

Wearable pressure sensors capable of sensitive, precise, and continuous measurement of physiological and physical signals have great potential for the monitoring of health status and the early diagnosis of diseases. This work introduces a 3D-printed rigid microbump-integrated liquid metal-based soft pressure sensor (3D-BLiPS) for wearable and health-monitoring applications. Using a 3D-printed master mold based on multimaterial fused deposition modeling, the fabrication of a liquid metal microchannel and the integration of a rigid microbump array above the microchannel are achieved in a one-step, direct process. The microbump array enhances the sensitivity of the pressure sensor (0.158 kPa-1 ) by locally concentrating the deformation of the microchannel with negligible hysteresis and a stable signal response under cyclic loading. The 3D-BLiPS also demonstrates excellent robustness to 10 000 cycles of multidirectional stretching/bending, changes in temperature, and immersion in water. Finally, these characteristics are suitable for a wide range of applications in health monitoring systems, including a wristband for the continuous monitoring of the epidermal pulse rate for cuffless blood pressure estimation and a wireless wearable device for the monitoring of body pressure using a multiple pressure sensor array for the prevention of pressure ulcers.


Assuntos
Impressão Tridimensional , Dispositivos Eletrônicos Vestíveis , Pressão , Temperatura , Tecnologia sem Fio
16.
ACS Appl Mater Interfaces ; 11(27): 24386-24394, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31192578

RESUMO

Inspired by the turbinate structure in the olfaction system of a dog, a biomimetic artificial nose based on 3D porous laser-induced graphene (LIG) decorated with palladium (Pd) nanoparticles (NPs) has been developed for room-temperature hydrogen (H2) detection. A 3D porous biomimetic turbinate-like network of graphene was synthesized by simply irradiating an infrared laser beam onto a polyimide substrate, which could further be transferred onto another flexible substrate such as polyethylene terephthalate (PET) to broaden its application. The sensing mechanism is based on the catalytic effect of the Pd NPs on the crystal defect of the biomimetic LIG turbinate-like microstructure, which allows facile adsorption and desorption of the nonpolar H2 molecules. The sensor demonstrated an approximately linear sensing response to H2 concentration. Compared to chemical vapor-deposited (CVD) graphene-based gas sensors, the biomimetic turbinate-like microstructure LIG-gas sensor showed ∼1 time higher sensing performance with much simpler and lower-cost fabrication. Furthermore, to expand the potential applications of the biomimetic sensor, we modulated the resistance of the biomimetic LIG sensor by varying laser sweeping gaps and also demonstrated a well-transferred LIG layer onto transparent substrates. Moreover, the LIG sensor showed good mechanical flexibility and robustness for potential wearable and flexible device applications.

17.
ACS Appl Mater Interfaces ; 11(26): 23639-23648, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31180635

RESUMO

Flexible and wearable pressure sensors have attracted a tremendous amount of attention due to their wider applications in human interfaces and healthcare monitoring. However, achieving accurate pressure detection and stability against external stimuli (in particular, bending deformation) over a wide range of pressures from tactile to body weight levels is a great challenge. Here, we introduce an ultrawide-range, bending-insensitive, and flexible pressure sensor based on a carbon nanotube (CNT) network-coated thin porous elastomer sponge for use in human interface devices. The integration of the CNT networks into three-dimensional microporous elastomers provides high deformability and a large change in contact between the conductive CNT networks due to the presence of micropores, thereby improving the sensitivity compared with that obtained using CNT-embedded solid elastomers. As electrical pathways are continuously generated up to high compressive strain (∼80%), the pressure sensor shows an ultrawide pressure sensing range (10 Pa to 1.2 MPa) while maintaining favorable sensitivity (0.01-0.02 kPa-1) and linearity ( R2 ∼ 0.98). Also, the pressure sensor exhibits excellent electromechanical stability and insensitivity to bending-induced deformations. Finally, we demonstrate that the pressure sensor can be applied in a flexible piano pad as an entertainment human interface device and a flexible foot insole as a wearable healthcare and gait monitoring device.


Assuntos
Técnicas Biossensoriais , Elastômeros/química , Nanotubos de Carbono/química , Dispositivos Eletrônicos Vestíveis , Elastômeros/uso terapêutico , Condutividade Elétrica , Humanos , Porosidade , Pressão
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