Pulmonary Delivery of Isoproterenol Aerosol Generated With Silicon-Based MHz Ultrasonic Nozzles

2009 ◽  
Author(s):  
S. C. Tsai ◽  
R. W. Mao ◽  
D. Mukai ◽  
S. K. Lin ◽  
J. Y. Yang ◽  
...  
Keyword(s):  
Upper Airway ◽  
Pulmonary Delivery ◽  
Drive Power ◽  
Drive Section ◽  
Metered Dose ◽  
Mems Technology ◽  
Lower Airways ◽  
Piezoelectric Drive ◽  
Silicon Based ◽  
Monodisperse Droplets

Monodisperse micron-sized aerosol is ideal for pulmonary drug delivery. This paper reports delivery of monodisperse aerosol of medicinal droplets generated by MHz ultrasonic nozzles using an anatomically realistic upper airway model. The MHz ultrasonic nozzle is fabricated using MEMS technology, and comprised of a piezoelectric drive section and a silicon resonator of multiple Fourier horns (see Fig. 1) [1]. The dissolved medication is pumped into a central channel (200×200 μm2) inside the nozzle and exits at the nozzle tip that vibrates longitudinally at the nozzle resonant frequency. The novel design of multiple horns facilitates generation of a column of monodisperse droplets at electric drive power as low as 15mW [1]. Monodisperse ethanol droplets 2.4 μm and water droplets 4.5 μm in diameter have been produced, respectively, using 1.5 MHz and 1.0 MHz nozzles. We used an aqueous solution of 25mg/ml (2.5wt%) β2-agonist (isoproterenol) for generation of monodisperse droplets using the 1.0 MHz ultrasonic nozzles. A yield of >54% (to the lower airways on total amount of inhaled isoproterenol basis), significantly higher than the reported highest lower airways deposition (32%) using metered-dose-inhalers (MDIs) [2], has been accomplished.

Swallow Pattern Generator Reconfiguration of the Respiratory Neural Network

2009 ◽  
Vol 18 (1) ◽  
pp. 3-12
Author(s):  
Andrea Vovka ◽  
Paul W. Davenport ◽  
Karen Wheeler-Hegland ◽  
Kendall F. Morris ◽  
Christine M. Sapienza ◽  
...  
Keyword(s):  
Behavioral Control ◽  
Upper Airway ◽  
Pattern Generator ◽  
Breathing Patterns ◽  
Motor Patterns ◽  
Control Assembly ◽  
Pharyngeal Swallow ◽  
Laryngeal Vestibule ◽  
Lower Airways ◽  
Swallow Apnea

Abstract When the nasal and oral passages converge and a bolus enters the pharynx, it is critical that breathing and swallow motor patterns become integrated to allow safe passage of the bolus through the pharynx. Breathing patterns must be reconfigured to inhibit inspiration, and upper airway muscle activity must be recruited and reconfigured to close the glottis and laryngeal vestibule, invert the epiglottis, and ultimately protect the lower airways. Failure to close and protect the glottal opening to the lower airways, or loss of the integration and coordination of swallow and breathing, increases the risk of penetration or aspiration. A neural swallow central pattern generator (CPG) controls the pharyngeal swallow phase and is located in the medulla. We propose that this swallow CPG is functionally organized in a holarchical behavioral control assembly (BCA) and is recruited with pharyngeal swallow. The swallow BCA holon reconfigures the respiratory CPG to produce the stereotypical swallow breathing pattern, consisting of swallow apnea during swallowing followed by prolongation of expiration following swallow. The timing of swallow apnea and the duration of expiration is a function of the presence of the bolus in the pharynx, size of the bolus, bolus consistency, breath cycle, ventilatory state and disease.

Site-specific sensitization in a murine model of allergic rhinitis: Role of the upper airway in lower airways disease

2002 ◽  
Vol 110 (6) ◽  
pp. 891-898 ◽  
Author(s):  
Christine McCusker ◽  
Martin Chicoine ◽  
Qutayba Hamid ◽  
Bruce Mazer
Keyword(s):  
Allergic Rhinitis ◽  
Murine Model ◽  
Upper Airway ◽  
Site Specific ◽  
Lower Airways

scholarly journals MEMs from the Nanoscale Up

2007 ◽  
Vol 129 (03) ◽  
pp. 24-29 ◽  
Author(s):  
Arthur C. Ratzel
Keyword(s):  
Leading Edge ◽  
Consumer Products ◽  
Mems Devices ◽  
Science And Engineering ◽  
Gas Damping ◽  
High Shock ◽  
Mems Technology ◽  
Silicon Based ◽  
Development Laboratory

This article discusses growing role of silicon micro-electron-mechanical systems (MEMS) technology in automotive and consumer products, telecommunications, radio-frequency applications, and medical care. The article also highlights that silicon-based MEMS devices must be constructed in clean rooms, such as one at Sandia's Microelectronics Development laboratory. According to engineers, the search for an in-depth understanding of wear mechanisms in dynamic silicon MEMS is expected to drive an ambitious wave of leading-edge research into microscale science and engineering, distinct from that which prevailed at the mesoscale. It has been found that gas damping between MEMS structures and the substrate, within the sealed package, can cause serious nonlinearities. While this doesn't lead to failure in the classic sense, it may make it harder to close a switch. On the plus side, gas damping can provide a cushion that enables a MEMS device to survive surprisingly high shock loads.

scholarly journals NANO-VESICLES OF SALBUTAMOL SULPHATE IN METERED DOSE INHALERS: FORMULATION, CHARACTERIZATION AND IN VITRO EVALUATION

2017 ◽  
Vol 9 (6) ◽  
pp. 100 ◽  
Author(s):  
Mona G. Arafa ◽  
Bassam M. Ayoub
Keyword(s):  
In Vitro Release ◽  
Pulmonary Delivery ◽  
Entrapment Efficiency ◽  
Reversed Phase ◽  
Molar Ratio ◽  
Metered Dose Inhalers ◽  
Salbutamol Sulphate ◽  
Novel Approach ◽  
Metered Dose

Objective: The present work was aimed to prepare niosomes entrapping salbutamol sulphate (SS) using reversed phase evaporation method (REV).Methods: Niosomes were prepared by mixing span 60 and cholesterol in 1:1 molar ratio in chloroform, SS in water was then added to organic phase to form niosomal SS. Formulations after evaporation of chloroform, freeze centrifuged then lyophilized, were evaluated for particles size, polydispersity index (Pdi), zeta-potential, morphology, entrapment efficiency (EE%) and in vitro release. For pulmonary delivery; metered dose inhalers (MDI) were prepared by suspending SS niosomes equivalent to 20 mg SS in hydrofluoroalkane (HFA). The metered valve was investigated for leakage rate, the total number of puffs/canister, weight/puff, dose uniformity and particle size.Results: The results showed spherical niosomes with 400-451 nm particles that entrapped 66.19% of SS. 76.54±0.132% SS release from niosomes that showed a controlled release profile for 8h. The leakage test was not exceeding 4 mg/3 d, the number of puffs were up to 200puffs/canister, the dose delivered/puff was 0.1 mg and 0.64-4.51μm niosomal aerosol.Conclusion: The results indicate an encouraging strategy to formulate a controlled drug delivery by entrapping (SS) in niosomes which could be packaged into (MDI) that met the requirements of (USP) aerosols guidelines which offering a novel approach to respiratory delivery.

An Ultrasonic Micro Knife Based on Triangular Silicon Horn Chip

2015 ◽  
Vol 645-646 ◽  
pp. 1363-1367
Author(s):  
Ting Ting Wang ◽  
Jing Wu ◽  
Ke Man Ying ◽  
Wen Gang Li ◽  
Hang Guo
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Invasive Surgery ◽  
Biological Tissues ◽  
Test Results ◽  
Fundamental Theory ◽  
Ultrasonic Scalpel ◽  
Mems Technology ◽  
Silicon Based

This paper presents a silicon-based ultrasonic scalpel for minimally invasive surgery. Starting from the fundamental theory, the micro ultrasonic scalpel using triangular silicon horn chip is designed and fabricated in detail. It is found that the magnification of the composed horn keeps 5.8 when size changes. A micro scalpel has been fabricated by MEMS technology. The test results show that a good performance in vibration and fit for puncturing biological tissues at the micro/nanoscale are obtained in the micro ultrasonic scalpel.

scholarly journals Silicon-Based Sensors for Biomedical Applications: A Review

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2908 ◽  
Author(s):  
Yongzhao Xu ◽  
Xiduo Hu ◽  
Sudip Kundu ◽  
Anindya Nag ◽  
Nasrin Afsarimanesh ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Microelectromechanical Systems ◽  
Human Life ◽  
Market Survey ◽  
Biomedical Sensing ◽  
Silicon Sensors ◽  
Mems Technology ◽  
Current Scenario ◽  
Silicon Based

The paper highlights some of the significant works done in the field of medical and biomedical sensing using silicon-based technology. The use of silicon sensors is one of the pivotal and prolonged techniques employed in a range of healthcare, industrial and environmental applications by virtue of its distinct advantages over other counterparts in Microelectromechanical systems (MEMS) technology. Among them, the sensors for biomedical applications are one of the most significant ones, which not only assist in improving the quality of human life but also help in the field of microfabrication by imparting knowledge about how to develop enhanced multifunctional sensing prototypes. The paper emphasises the use of silicon, in different forms, to fabricate electrodes and substrates for the sensors that are to be used for biomedical sensing. The electrical conductivity and the mechanical flexibility of silicon vary to a large extent depending on its use in developing prototypes. The article also explains some of the bottlenecks that need to be dealt with in the current scenario, along with some possible remedies. Finally, a brief market survey is given to estimate a probable increase in the usage of silicon in developing a variety of biomedical prototypes in the upcoming years.

PneumoniaCheck: A Device for Sampling Lower Airway Aerosols

2010 ◽  
Vol 4 (4) ◽  
Author(s):  
Tamera L. Scholz ◽  
Prem A. Midha ◽  
Larry J. Anderson ◽  
David N. Ku
Keyword(s):  
Upper Airway ◽  
Lower Airway ◽  
High Quality ◽  
Effective Separation ◽  
Specimen Collection ◽  
Collection Device ◽  
Lower Lung ◽  
Lower Airways ◽  
Selective Collection

The pathogens causing pneumonia are difficult to identify because a high quality specimen from the lower lung is difficult to obtain. A new specimen collection device is designed to collect aerosol specimens selectively from the lower lung generated during deep coughing. The PneumoniaCheck device utilizes a separation reservoir and Venturi valve to segregate contents from the upper and lower airways. The device also includes several specially designed features to exclude oral contaminants from the sample and a filter to collect the aerosolized pathogens. Verification testing of PneumoniaCheck demonstrates effective separation of upper airway gas from the lower airway gas (p<0.0001) and exclusion of both liquid and viscous oral material (p<0.0001) from the collection chamber. The filters can collect 99.9997% of virus and bacteria sized particles from the sampled lower lung aerosols. The selective collection of specimens from the lower airway may aid in the diagnosis of specific pathogens causing pneumonia.

Silicon-based Micro Direct Methanol Fuel Cell Stack to Power Portable Devices Using MEMS Technology

2014 ◽  
Vol 153 (1) ◽  
pp. 133-139 ◽  
Author(s):  
Chunguang Suo ◽  
Wenbin Zhang ◽  
Guangmin Wu ◽  
Hua Wang ◽  
Xiaohong Quan
Keyword(s):  
Fuel Cell ◽  
Direct Methanol Fuel Cell ◽  
Portable Devices ◽  
Fuel Cell Stack ◽  
Direct Methanol ◽  
Mems Technology ◽  
Silicon Based ◽  
Methanol Fuel Cell

Characterization of 0.5 MHz Silicon-Based Ultrasonic Nozzles Using Multiple Fourier Horns

2003 ◽  
Vol 782 ◽  
Author(s):  
Shirley C. Tsai ◽  
Yu L. Song ◽  
Yuan F. Chou ◽  
Terry K. Tseng ◽  
W. J. Chen ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Vibration Amplitude ◽  
Longitudinal Vibration ◽  
Impedance Analysis ◽  
Experimental Results ◽  
Vibration Measurement ◽  
Drive Power ◽  
Cross Sectional ◽  
Half Wavelength ◽  
Silicon Based

ABSTARCTThis paper presents the experimental results of impedance analysis and longitudinal vibration measurement of micro-fabricated 0.5 MHz silicon-based ultrasonic nozzles. Each nozzle is made of a piezoelectric drive section and a silicon-resonator consisting of multiple Fourier horns each with half wavelength design and twice amplitude magnification. The experimental results verified the simulation prediction of one pure longitudinal vibration mode at the resonant frequency in excellent agreement with the design value. Furthermore, at the resonant frequency, the measured longitudinal vibration amplitude gain at the nozzle tip increases as the number of Fourier horns (n) increases in good agreement with the theoretical value of 2n. Using this design, very high vibration amplitude at the nozzle tip can be achieved with no reduction in the tip cross sectional area. Therefore, the required electric drive power should be drastically reduced, decreasing the likelihood of transducer failure in ultrasonic atomization.

Sign in / Sign up

Export Citation Format

Share Document