Medical devices & sensors最新文献

The COVID-19 pandemic has produced critical shortages of ventilators worldwide. There is an unmet need for rapidly deployable, emergency-use ventilators with sufficient functionality to manage COVID-19 patients with severe acute respiratory distress syndrome. Here, we show the development and validation of a simple, portable and low-cost ventilator that may be rapidly manufactured with minimal susceptibility to supply chain disruptions. This single-mode continuous, mandatory, closed-loop, pressure-controlled, time-terminated emergency ventilator offers robust safety and functionality absent in existing solutions to the ventilator shortage. Validated using certified test lungs over a wide range of compliances, pressures, volumes and resistances to meet U.S. Food and Drug Administration standards of safety and efficacy, an Emergency Use Authorization is in review for this system. This emergency ventilator could eliminate controversial ventilator rationing or splitting to serve multiple patients. All design and validation information is provided to facilitate ventilator production even in resource-limited settings.

The flow behaviour and injectability of calcium phosphate cements are outcomes of the complex interplay between time-dependent processes of dissolution, nucleation and crystal growth. Their dependence on shear strains, frequencies and rates has been revealed by rheological investigation of the setting processes of a brushite cement under torsional flow. Various oscillatory torsional strain amplitudes and frequencies were seen to promote dissolution or delay crystal intergrowth compared to quiescently set cement samples. Oscillatory torsional strain amplitudes higher than the linear viscoelastic strain limit resulted in a pronounced lag in crystal intergrowth. Dissolution was enhanced and setting was promoted with increasing frequency and strain amplitude within the linear viscoelastic strain range. Changing the preshearing mode to steady torsion increased energy spent to microstructural deformation, counteracting the beneficial vibratory effect on cement setting kinetics, and produced a net retardation by the disruption of the crystal network structure. Such deformation history can be created in the cement suspension prior to injection during clinical practice by precise adjustment of the preshearing modes and parameters to enable the orthopaedic surgeon tailor the setting time, flow behaviour and injectability of calcium phosphate cements in situ without altering the cement chemistry, hence bioactivity.

Versatile applications of triboelectric nanogenerator as a microsystem component have widened the access to advanced healthcare monitoring and green energy systems. Recent research on wearable electronic technologies has been focusing on more complex architecture and costly materials for sensory applications resulting in less commercial feasibility. Here, we report a biocompatible, cost-effective, highly sensible, structurally simple, multifunctional and wearable triboelectric nanogenerator (TENG) as a universal health monitoring device. This triboelectric universal health monitoring device (TUHMD) was fabricated with cellulose paper and polydimethylsiloxane (PDMS)/polytetrafluoroethylene (PTFE) copolymer electrodes. This device demonstrated high sensitivity and notable identical signals on diverse body motions related to body muscles and respiratory system by mechanical triggering. The device was also observed to be sensitive to vocal cord vibration. Integration of this device with computer-aided system offers real-time data of physiological movement, potentially useful for personalized medicine, rehabilitation and remote monitoring of patients. The device was also tested from 30 to 90 beat per minute (BPM) load frequencies to observe the triboelectric performance of the device. TUHMD showed response as a triboelectric nanogenerator with a range of 12 V with negligible charge accumulation, along with a maximum capacitive performance of 11 F. This smart device showed a potential to be an advanced biomedical sensor for maintaining full health care or monitoring applications.

We have developed a pixel-based drug release system that consists of several miniature drug cartridges capable of releasing accurate dosages and maintaining the drug within a therapeutic window. To achieve the goal of personalized medicine that takes into account targeted dosages, single or multiple miniature cartridges can be used to release the drug. Moreover, a release cascade with individual pixels in a time-lag fashion can maintain the drug within the therapeutic window while prolonging its duration of activity. For high quality, dosage control, and precise administration, the amount of drug released from each miniature cartridge needs to be predicted accurately. As such, the total released amount over a specific time and the number of involved miniature cartridges can be optimized. We established a model based on analogizing our voltage-triggered drug release system to capacitors, and mathematically determined the amount of release from every miniature cartridge. The model predicted that the procedure can be fitted using an exponential function. The characteristic time for the exponential fit was used to derive the predicting formula to be calibrated for each drug. We have shown that after calibration, the release of each miniature cartridge with different drugs and various initial loads can be predicted; therefore, a dosage release can be achieved based on each patient's need.

Malaria elimination programmes are dependent on a rapid, cost-effective and portable diagnostic tool to detect and quantify malaria parasites in human blood. Herein, we report a cost-effective and portable nuclear magnetic resonance (pNMR) for malaria diagnosis. In this present study, we have developed and characterized a sensitive and low-cost novel on-chip NMR probe. This NMR probe has improved mismatching problem between radiofrequency (RF) coil and transmission line that results in enhancement in NMR sensitivity. Developed pNMR represents a rapid, cost-effective and highly sensitive method to detect very low parasitaemia plasmodium falciparum (0.0001%) in infected human blood in comparison with other available malaria diagnosis techniques. The experimental results show that very low parasitic load can be detected rapidly by the change in the transverse relaxation rate (T₂) of NMR, suggesting a good sensitivity. A good linear relationship with a correlation coefficient of 0.94 between the change in transverse relaxation rate (ΔT₂) and the different parasitaemia (%) has been observed, indicating that pNMR is a potential tool for real-time, reusable and high-sensitivity analysis of malaria parasite in human blood.

One of the current challenges in biosensors is to develop a device with high biocatalytic activity, high sensitivity, high selectivity, low detection limit, fast response towards the analyte, eco-friendly and also low-cost price. Bacterial cellulose (BC), a pure mat of nanosized cellulose fibres, represents an alternative to the development of new materials for sensing applications. BC has a high surface area, high porosity and water absorbance, and it is a biocompatible and eco-friendly polymer. In order to produce BC-based materials for sensing devices, the original BC network can be preserved or destroyed. In both cases, the introduction of a second phase in order to improve or modify the properties of native BC is possible. Metal nanoparticles, metal oxides, carbon-based materials, conductive polymers and enzymes are among the materials that have been combined with BC to prepare novel biosensor platforms. BC biosensors can be classified according to their output signal as resonant, optical or electrochemical biosensors. Some of the applications of BC-based biosensors include pollutant biosensors, humidity, mass and gas biosensors, and biomedical biosensors to detect glucose and dopamine, among other sensing targets.

This report demonstrates synthesis of black phosphorus (BP) from red phosphorus using sonochemistry and the direct growth of highly air-stable BP on cellulose paper using hydrothermal method with PDMS as passivation and its utilization in human motion monitoring system. PDMS not only hinders the oxidation of BP but also provides flexibility to the device, thereby allowing the use of paper-based device as strain sensor. Fabricated device exhibits gauge factor of 6.1, which is comparable with the devices fabricated using sophisticated cleanroom techniques, and device is tested for 2,000 bending cycles revealing excellent reliability and repeatability. Device displayed excellent hysteresis suggesting that tunnelling effect is responsible for the current change of the device upon the external strain. Mathematical model is formulated to describe tunnelling conduction which matched the experimental results. Further, device exhibits excellent air stability for 98 days wherein negligible change in resistance and strain sensing performance is observed. Fabricated device is integrated onto different parts of the human body for its real-time application in human motion monitoring. Successful demonstration of the direct growth of highly air-stable BP on flexible and biodegradable cellulose paper opens up new avenues of research in optoelectronics, health care, security etc.

Certain laboratory testing methods for the characterization of biomaterials, which can be regarded as essentially nonlinear sensors, have become widely adopted in recent decades. These techniques, namely dynamic mechanical analysis (DMA), electrochemical impedance spectroscopy (EIS) and temperature-modulated differential scanning calorimetry (TMDSC), employ similar fundamental approaches in their different analyses, wherein materials are subjected to alternating (sinusoidal) stress, electrical potential and temperature change, respectively, and both the linear (in-phase) and nonlinear (out-of-phase) responses are analysed to yield novel information unavailable with the corresponding traditional linear analytical techniques. This review article discusses the general experimental procedures and underlying principles for these three nonlinear analytical techniques and the type of information obtained with each approach, compared with that from the corresponding linear tests, and presents examples from the literature about their wide-ranging application. While the focus is on dental biomaterials, additional examples for medical biomaterials are provided to illustrate further examples of the novel information that can be obtained from the use of these three nonlinear tests. The underlying philosophical similarity (analyses of nonlinear responses to different types of sinusoidal physical inputs) of these three sensor techniques is emphasized.

Magnetic nanoparticles (MNP) have emerged as a relevant material for biomedical applications based on drug delivery systems and magnetic hyperthermia. When carefully tailored, their surface properties can enhance the solubility, bioavailability, permeability, metabolism, excretion, cell internalization and recognition of many medicines, which are parameters highly desired when one think in the development and efficiency increasing of several therapies. Allied to it, an interesting synergism can be achieved by the use of magnetic fields as trigger of drug release from thermosensitive polymer-modified MNP or as a tool to increase accumulation of medicine in specific site. Faced it, here it shows how surface engineering of MNP can improve its biomedical relevance due to enhancement of cellular recognition, biocompatibility and drug release of several medicines. Furthermore, particular attention will be paid to the use of magnetic hyperthermia, which has acted synergic to improve MNP effects of many drug delivery systems.