Label-Free Protein Analysis Using Liquid Chromatography with Gravimetric Detection.

The detection and analysis of proteins in a label-free manner under native solution conditions is an increasingly important objective in analytical bioscience platform development. Common approaches to detect native proteins in solution often require specific labels to enhance sensitivity. Dry mass sensing approaches, by contrast, using mechanical resonators, can operate in a label-free manner and offer attractive sensitivity. However, such approaches typically suffer from a lack of analyte selectivity as the interface between standard protein separation techniques and micro-resonator platforms is often constrained by qualitative mechanical sensor performance in the liquid phase. Here, we describe a strategy that overcomes this limitation by coupling liquid chromatography with a quartz crystal microbalance (QCM) platform by using a microfluidic spray dryer. We explore a strategy which allows first to separate a protein mixture in a physiological buffer solution using size exclusion chromatography, permitting specific protein fractions to be selected, desalted, and subsequently spray-dried onto the QCM for absolute mass analysis. By establishing a continuous flow interface between the chromatography column and the spray device via a flow splitter, simultaneous protein mass detection and sample fractionation is achieved, with sensitivity down to a 100 μg/mL limit of detection. This approach for quantitative label-free protein mixture analysis offers the potential for detection of protein species under physiological conditions.ERC EPSRC Frances and Augustus Newman Foundation Oppenheimer Early Career Fellowship Nanotechnologies Doctoral Training Centre Fluidic Analytics Lt

Label-Free Protein Analysis Using Liquid Chromatography with Gravimetric Detection.

The detection and analysis of proteins in a label-free manner under native solution conditions is an increasingly important objective in analytical bioscience platform development. Common approaches to detect native proteins in solution often require specific labels to enhance sensitivity. Dry mass sensing approaches, by contrast, using mechanical resonators, can operate in a label-free manner and offer attractive sensitivity. However, such approaches typically suffer from a lack of analyte selectivity as the interface between standard protein separation techniques and micro-resonator platforms is often constrained by qualitative mechanical sensor performance in the liquid phase. Here, we describe a strategy that overcomes this limitation by coupling liquid chromatography with a quartz crystal microbalance (QCM) platform by using a microfluidic spray dryer. We explore a strategy which allows first to separate a protein mixture in a physiological buffer solution using size exclusion chromatography, permitting specific protein fractions to be selected, desalted, and subsequently spray-dried onto the QCM for absolute mass analysis. By establishing a continuous flow interface between the chromatography column and the spray device via a flow splitter, simultaneous protein mass detection and sample fractionation is achieved, with sensitivity down to a 100 μg/mL limit of detection. This approach for quantitative label-free protein mixture analysis offers the potential for detection of protein species under physiological conditions.ERC EPSRC Frances and Augustus Newman Foundation Oppenheimer Early Career Fellowship Nanotechnologies Doctoral Training Centre Fluidic Analytics Lt

Multidisciplinary design and flight testing of a remote gas/particle airborne sensor system

The main objective of this paper is to describe the development of a remote sensing airborne air sampling system for Unmanned Aerial Systems (UAS) and provide the capability for the detection of particle and gas concentrations in real time over remote locations. The design of the air sampling methodology started by defining system architecture, and then by selecting and integrating each subsystem. A multifunctional air sampling instrument, with capability for simultaneous measurement of particle and gas concentrations was modified and integrated with ARCAA’s Flamingo UAS platform and communications protocols. As result of the integration process, a system capable of both real time geo-location monitoring and indexed-link sampling was obtained. Wind tunnel tests were conducted in order to evaluate the performance of the air sampling instrument in controlled nonstationary conditions at the typical operational velocities of the UAS platform. Once the remote fully operative air sampling system was obtained, the problem of mission design was analyzed through the simulation of different scenarios. Furthermore, flight tests of the complete air sampling system were then conducted to check the dynamic characteristics of the UAS with the air sampling system and to prove its capability to perform an air sampling mission following a specific flight path

Design of Soil Moisture Sensor for Validation of Passive Microwave Remote Sensed Soil Moisture Data

Soil Moisture is an important parameter that is of immense importance in the field of civil engineering, agriculture and ecology. Development of weather patterns and intake of nutrient by plants depend on soil moisture. In this paper, the design of sensor is described that uses the electrical resistance attribute of soil moisture. The soil moisture product of Advanced Microwave Scanning Radiometer-2 on board GCOM satellite of Japan Aerospace Exploration Agency (JAXA) is then compared with the soil moisture obtained from the designed sensor. Analysis shows the variability of the soil moisture values measured by both the satellite as well as the actual soil moisture measured by gravimetric method for the samples collected from different locations. The designed sensor shows similar variations in its output. Hence, the designed sensor can be used for checking the variations happening in soil moisture values instantaneously and can be used to validate the soil moisture product of remote sensing satellites for different location

Tunable mechanical resonator with aluminum nitride piezoelectric

The electromechanical response of piezoelectrically-actuated AlN micromachined bridge resonators has been characterized using laser interferometry and electrical admittance measurements. We compare the response of microbridges with different dimensions and buckling (induced by the initial residual stress of the layers). The resonance frequencies are in good agreement with numerical simulations of the electromechanical behavior of the structures. We show that it is possible to perform a rough tuning of the resonance frequencies by allowing a determined amount of builtin stress in the microbridge during its fabrication. Once the resonator is made, a DC bias added to the AC excitation signal allows to fine-tune the frequency. Our microbridges yield a tuning factor of around 88 Hz/V for a 500 ?m-long microbridge

Mechanical Drawing of Gas Sensors on Paper

Pencil it in: Mechanical abrasion of compressed single-walled carbon nanotubes (SWCNTs) on the surface of paper produces sensors capable of detecting NH[subscript 3] gas at sub-ppm concentrations. This method of fabrication is simple, inexpensive, and entirely solvent-free, and avoids difficulties arising from the inherent instability of many SWCNT dispersions.Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (W911NF-07-D-004)National Institutes of Health (U.S.) (National Cancer Institute (U.S.) Postdoctoral Fellowship Grant F32A1571997

루테늄/전도성 고분자 하이브리드 나노입자 제조 및 수소 화학센서로의 응용

학위논문(박사)--서울대학교 대학원 :공과대학 화학생물공학부,2019. 8. 장정식.최근 우수한 물성과 전기적, 화학적 성능을 보이는 나노재료의 연구와 개발에 대해 지대한 관심이 있다. 특히, 무기물과 유기물을 결합한 복합나노재료는 각 물질의 상호작용으로 서로의 단점을 보완하고 우수한 물성을 보이기에 많은 산업분야에서 연구가 진행 중이다. 그 중에서도 금속과 전도성 고분자를 결합한 복합나노재료는 고분자의 낮은 기계적 특성을 보완해주고 금속 나노재료의 응집 현상을 막아주어 높은 안정성을 가지고 있다. 또한 뛰어난 성능의 전기적 특성을 가지고 있기 때문에 전기화학센서, 형광센서, 촉매, 에너지 변환 및 저장 장치에서 주목 받고 있다. 하지만, 현재 일정한 형태의 복합나노재료를 제조하는 기술이 부족하고 적용하는 금속 또한 백금, 금, 은 등의 안정성이 높은 귀금속에만 국한되어 있기 때문에 더 많은 연구가 필요한 상황이다. 스마트 화학센서는 트랜스듀서를 기반으로 하는 장치로 특징 있는 환경적 요소들을 감지하는데 뛰어난 성능을 보인다. 센서는 타겟물질을 감지하는 센싱 트랜스듀서가 필요한데 이 트랜스듀서는 전기, 온도, 형광 등 다양한 신호의 변화를 통해 타겟물질을 감지할 수 있으며 트랜스듀서가 감지한 신호를 디지털 신호로 바꾸어 디지털 기기를 통해 타겟물질의 유무 및 농도 변화를 확인하여 위험하고 폭발 가능성이 있는 기체에 대해 미리 알려주는 역할을 할 수 있기에 뛰어난 성능을 가진 센서는 많은 산업분야에서 유용하게 사용될 수 있다. 따라서, 뛰어난 감지 성능을 가지는 센싱 트랜스듀서 물질개발은 중요한 요소 중 하나이다. 뛰어난 성능을 판단하는 기준은 다음의 6가지 기준을 제시할 수 있다: 1) 높은 감도; 2) 넓은 범위의 감지 농도; 3) 타겟물질에 대한 선택성; 4) 빠른 감지와 회복 속도; 5) 반복감지에 대한 안정성; 6) 상온에서의 감지가능, 이렇게 6가지의 성능에 대한 테스트가 필요하다. 본 학위 논문에서는 전도성 고분자의 일종인 폴리피롤 나노입자 위에 금속물 중 하나인 루테늄 나노구조물이 올라간 일정한 형태의 금속과 전도성 고분자의 하이브리드 복합나노재료를 간단하고 창의적인 방법을 이용하여 제조하고, 이들의 전기적 물성을 체계적으로 고찰하여 센서용 트랜스듀서로 적용하는 연구를 기술하였다. 우선, 카르복실기를 함유한 폴리피롤 나노입자를 제조하고 이를 분산한 수용액에 루테늄 전구체를 넣어 초음파처리와 화학적 환원을 통해 루테늄 나노입자가 일정하게 박힌 폴리피롤 나노입자를 제조하였다. 이때, 루테늄 전구체의 농도를 조절하여 폴리피롤 나노입자 표면에 도입되는 루테늄 나노입자의 밀도를 조절하였으며 루테늄 나노입자의 밀도에 따른 수소 감지성능을 비교하였다. 그 결과, 루테늄 나노입자의 밀도가 증가함에 따라 센서가 감지할 수 있는 수소가스의 농도가 낮아지고 더 넓은 농도범위의 수소가스를 감지할 수 있는 것을 확인하였다. 더 나아가, 산 용액과 염기 용액을 이용하여 복합나노입자에 화학적 처리를 했을 시 루테늄 나노입자와 폴리피롤 나노입자에 어떤 구조적 변화가 발생하고 이 변화가 수소감지 성능에 미치는 영향에 대하여 연구하였다. 결과에 따르면 산과 염기 용액 처리에 의해서 루테늄 나노입자의 구조에는 변화가 생기지 않는 것을 확인하였다. 하지만, 처리하는 용액의 pH가 낮아질수록 폴리피롤의 고분자 구조가 이중 분극자 형태의 구조를 가지는 것을 확인 할 수 있었다. 이에 따라 트랜스듀서가 수소를 감지하는 속도와 감지 후 원상태로 회복하는 속도가 더 빨라지는 것을 확인 할 수 있었다. 감지농도와 감지가능한 농도범위에는 큰 변화가 발생하지 않는 것을 통해 수소감지에는 루테늄이 필수적으로 필요한 것 또한 확인 가능하였다. 마지막으로, IoT 시대가 도래함에 따라 이에 맞춰 제조한 트랜스듀서를 무선센서로 응용하는 연구를 진행하였다. 수동적 RFID 무선태그를 이용하면 배터리가 없이 신호를 주고 받을 수 있어 소형화가 가능하고 환경을 고려하지 않고 어디에든 적용가능한 무선센서를 제조할 수 있다. 이를 위해 RFID 무선태그의 일정부분에 산소 플라즈마와 화학적 처리를 통하여 아미노 관능기를 도입하였고 촉매를 이용하여 폴리피롤 나노입자 표면의 카르복실기와 공유결합시켜 안정적이고 단단하게 트랜스듀서 물질을 RFID 무선태그 표면에 도입하는 실험을 진행하였다. 그 결과, 수소가스의 유무에 따라 무선신호가 변화하는 것을 확인하였고 농도의 변화에 따라서도 신호변화 크기가 달라져 농도 측정 또한 가능한 것을 확인하였다. 정리하면, 본 학위 논문에서는 폴리피롤 나노입자 표면에 루테늄 나노입자를 고르게 도입하여 표면적이 극대화되고 수소에 대하여 선택적으로 반응할 수 있는 복합나노재료를 제조하였으며 수소화학센서와 무선센서로 응용 가능성에 대한 연구를 수행하였다. 본 학위 논문에서 사용된 간단하고 독창적 제조방법과 구조 변형 방법들은 다양한 나노물질의 제조에도 응용 가능할 것으로 기대된다.Recently, nanomaterial research receives attention due to excellent physical and chemical properties and electrical characters. Especially, inorganic and organic components hybrid nanomaterials are researched in various industrial areas because each component complements weaknesses and strengthens advantages. In particular, hybrid nanomaterials with metal and conducting polymer prevent poor mechanical properties such as brittleness and deficient processibility of polymeric nanomaterials and lack of stability due to the Ostwald ripening process of low dimensional metal nanaomaterials. Also, the combination of metallic materials with polymeric compounds provides an excellent functionality with high performance as well as enhanced stability and good processability. However, the limitation of applied metal, only Pt, Au, and Ag, and fabrication method of uniform hybrid nanomaterials are important tasks for researchers. Smart chemical sensor is transducer based device which has excellent performance to detect environmental elements. It needs sensing materials to detect target analyte which display electrical, thermal, or optical signal change by target analyte. High-performance sensing transducer is absolutely wanted because the sensor has to preindicate combustible, flammable, and toxic gases, monitoring air-fuel ratio in combustion engines, detecting food spoilage, and ambient oxygen level monitoring to prevent dangerous situations in diverse industrial environments. There are six standards to decide high-performance sensing transducer: 1) low minimum detectable level (MDL) to target analyte; 2) Wide detection range; 3) Selectivity; 4) Fast response and recovery time; 5) Cycle stability; 6) Sensing ability at room temperature. This dissertation describes facile and creative method to fabricate ruthenium nanoclusters decorated carboxylic polypyrrole nanoparticles, studies electrical and structural characters of composites scienctifically, and suggests them as sensing transducer for hydrogen sensor. First, carboxyl functional groups included polypyrrole nanoparticles (CPPyNPs) were fabricated by microemulsion. Then, ultrasonication and chemical reducing agent methods were used to embed ruthenium nanoclusters, reduced from ruthenium precursors, on the surface of carboxylated polypyrrole nanoparticles. Furthermore, the density of ruthenium nanoclusters on the CPPyNP surface was controlled by injected ruthenium precursor concentration and the effect of variable ruthenium densities on CPPyNP surface for hydrogen sensing performance was analyzed. As a result, higher ruthenium density on CPPyNP surface showed lower minimum detectable level and wider detecting range for hydrogen gas detection. Second, chemical treatment by acid and base aqueous solvents was processed to Ru/CPPyNPs and structural changes of ruthenium nanoclusters and CPPyNPs were observed. There was no transition in ruthenium nanoclusters. However, polypyrrole polymer chain was reversibly changed among neutral, polaron, and bipolaron states by treatment of acid and base aqueous solvents. Hence, the response and recovery times of hydrogen gas detection were changed due to transition of charge carrier (hole) density and mobility in polypyrrole backbone structure. At last, Ru/CPPyNPs application as sensing material for wireless chemical sensor was demonstrated because the wireless chemical sensor becomes important technology for future IoT age. Especially, passive RFID tag is focused for wireless sensor because no battery is needed for tag operation. Thus, miniaturization and adaptation of wireless sensor is practicable. For these purposes, oxygen plasma and silane treatment were applied to the part of RFID tag to introduce amino functional groups and these groups were connected with carboxyl functional groups on CPPyNPs rigidly and stably. As a result, the reflectance change by hydrogen gas was displayed and the amount of change was differed from various hydrogen gas concentrations. Clearly, this dissertation proves the facile fabrication of ruthenium nanoclusters uniformly decorated carboxylated polypyrrole nanoparticles and the possibility of application for hydrogen chemical sensor and wireless sensor. The facile and creative hybrid nanocomposites fabrication method and chemical treatment to modify structural chain are expected to utilize for fabrication of other nanomaterials.Abstract i List of Abbreviations v List of Figures x List of Tables xx Table of Contents xxi 1. Introduction 1 1.1. Background 1 1.1.1. Conducting polymer 1 1.1.1.1. Doping 5 1.1.1.2. Polypyrrole 8 1.1.2. Nanomaterial 14 1.1.2.1. Conducting polymer nanomaterial 17 1.1.2.1.1. Polypyrrole nanoparticle 22 1.1.2.2. Metal nanomaterial 24 1.1.2.3. Metal/Conducting polymer hybrid nanomaterial 27 1.1.3. Sensor application 29 1.1.3.1. Resistive chemical sensor 31 1.1.3.1.1. Hydrogen gas sensor 34 1.1.3.2. Wireless sensor 35 1.1.3.2.1. RFID wireless sensor 36 1.2. Objectives and Outlines 38 1.2.1. Objectives 38 1.2.2. Outlines 38 2. Experimental Details 41 2.1. Ruthenium/polypyrrole hybrid nanoparticle for hydrogen chemical sensor 41 2.1.1. Materials 41 2.1.2. Fabrication of ruthenium/polypyrrole hybrid nanoparticle 41 2.1.3. Electrical measurement of Ru/CPPyNP attached chemiresistive sensor 43 2.1.3. Characterization 44 2.2. Acid-base treatment of Ru/CPPyNPs to control the chemiresistive properties of hydrogen chemical sensor 48 2.2.1. Materials 48 2.2.2. Acid-base treatment of Ru/CPPyNPs 48 2.2.3. Electrical measurement of acid-base treated Ru/CPPyNP attached chemiresistive sensor 49 2.2.4. Characterization 50 2.3. Wireless hydrogen sensor application of Ru/CPPyNPs 52 2.3.1. Materials 52 2.3.2. Fabrication of Ru/CPPyNPs introduced UHF-RFID wireless sensor 52 2.3.3. Radio frequency measurement of the Ru/CPPyNPs attached UHF-RFID wireless hydrogen sensor 54 2.3.4. Characterization 55 3. Results and Disccusion 56 3.1. Ruthenum/polypyrrole hybrid nanoparticle for hydrogen chemical sensor 56 3.1.1. Fabrication of Ru/CPPyNP 56 3.1.2. Material analysis of Ru/CPPyNP 64 3.1.3. Characterization of Ru/CPPyNP chemiresistive sensor electrode 69 3.1.4. Electrical measurement of Ru/CPPyNP based hydrogen gas chemical sensor 73 3.2. Acid-base treatment of Ru/CPPyNPs to control the chemiresistive properties of hydrogen chemical sensor 87 3.2.1. Morphology change observation of Ru/CPPyNPs by acid-base treatment 87 3.2.2. Material analysis of acid and base treated Ru/CPPyNPs 94 3.2.3. Electrical characterization for acid and base solvents treated Ru/CPPyNPs 103 3.2.4. Electrical measurement of acid and base treated Ru/CPPyNPs based hydrogen gas chemical sensor 106 3.3. Wireless hydrogen sensor application of Ru/CPPyNPs 118 3.3.1. Fabrication of UHF-RFID based wireless hydrogen gas sensor 118 3.3.2. Wireless sensor measurement of Ru/CPPyNPs attached UHF-RFID tag 123 3.3.3. Flexibility test of Ru/CPPyNPs attached UHF-RFID tag for wireless hydrogen sensor 135 4. Conclusion 139 Reference 143 국문초록 151Docto

DESIGN OF A PROTOTYPE UNMANNED LIGHTER-THAN-AIR PLATFORM FOR REMOTE SENSING: CONTROL, ALIMENTATION, AND PROPULSION SYSTEMS

This work presents several aspects related to the design of a new concept for a Remotely Piloted Aircraft System (RPAS), specifically, a Lighter-Than-Air (LTA) platform for the remote sensing of medium-sized rural and urban areas. The airship’s payload is intended to carry an array of sensors ranging from high-definition video cameras to hyperspectral sensors, a thermographic camera, and a LiDAR system, which all require power alimentation during low-speed surveying for fine mapping. Here, a fuel cell design solution, combined with supercapacitors, is proposed. The system is designed to provide energy for both the onboard sensors and the propulsion and thrust vector control system. In this regard, the design and optimization of the propeller blades, using Blade Element Momentum Theory (BEMT), is discussed as well, in a multidisciplinary optimisation fashion. A twin paper describes the other structural aspects of the airship design

Metal Hydrides and Related Materials - Energy Carriers for Novel Hydrogen and Electrochemical Storage

The seventh edition of the International Renewable and Sustainable Energy Conference (IRSEC) was held in Agadir (Sofitel Royal Bay, November 27–30, Morocco) under the Program Chair of Prof. Ahmed Ennaoui (IRESEN). IRSEC, as one of the biggest conferences in north Africa, aims at creating an international forum to facilitate discussions and exchanges in all aspects of renewable and sustainable energy. This Viewpoint will summarize the scientific presentations and stimulated discussions during the Special Session (November 28–29) on Metal Hydrides’ Energy covering topics of metal hydrides and energy related issues for innovative processes and technologies, with a focus on magnesium-based hydrides, intermetallic hydrides, complex and melt hydrides, porous materials, and thin films