This research was supported by the "Development of technologies for safety evaluation and standardization of nanomaterials and nanoproducts" (10059135)" through the Korea Evaluation Institute of Industrial Technology by the Korean Ministry of Trade, Industry &amp; Energy.

악기 및 표본 1. 준비 <ol><li> Abrasor <ol><li> 80 RPM - 마모 시험기에 기초하여, 하나의 시료 회전 스테이지 (140mm 직경)이 연마 휠 홀더, 및 (30)의 회전 속도와 함께 abrasor를 사용한다. </li><li> 또한, 시험편에 하중을 적용 연마 휠 홀더에 연마 휠을 고정 가중치를 사용한다. </li><li> 도 3에 도시 된 바와 같이, 더 abrased 입자 현탁액을 제공하는 추가 공기 유입구를 설치한다. 1/8 &quot;를 사용하여 지름의 튜브 위에 위치 15mm 떨어진 시험편의 중심으로부터 40mm. </li></ol></li><li> 마모 휠 <ol><li> 모래 종이 (100 모래와 새로운)와 마모 휠 (55mm 직경 13 mm 두께)를 감싸. </li></ol></li><li> 표본 <ol><li> 시편은 마모 시험의 나노 물질을 함유하는 복합체이다. abrasor에 설치하기 위해, 시편 준비 위트해야한다H 140mm 직경. </li></ol></li><li> 방 <ol><li> 정전기력에 의한 입자 침착을 방지하기 위해 챔버 벽 스테인리스를 사용한다. 챔버 (부피 1m 3) (표 1) 내부 abrasor두고, 각각 상기 챔버의 상부 및 하부에 공기 흡입구 및 배출구를 찾아. 균일하게 혼합 된 입자 흐름을 달성하기 위해 공기 출구 세 공판 구성된 혼합기를 사용한다. </li></ol></li><li> 중화제 <ol><li> 정전기가 대전 된 입자는 챔버 벽 상에 입자 퇴적을 향상 같이, 입자의 충전 상태를 최소화하기 위해 중화제 (연 X 선 이온화 장치)를 사용한다. </li></ol></li><li> 온라인 측정 장치 (12), (13) <ol><li> 제조자의 지시에 따라 입자 수 농도와 입도 분포를 측정하기위한 CPC와 OPC를 사용한다. </li><li> outle에서 CPC와 OPC 설치챔버의 t는 입자 수 농도와 입도 분포를 측정 하였다. </li></ol></li><li> 입자 샘플링 악기 <ol><li> 입자 형태 및 구성 요소를 분석하는 입자 샘플러 함유 여과재 또는 TEM 그리드를 사용하여 공개 된 입자 샘플. </li><li> 분리 된 입자의 형태를 분석하기 위해 상기 챔버의 출구에 입자 샘플러 함유 여과재 또는 TEM 그리드를 설치한다. </li></ol></li></ol> 나노 입자 릴리스 2. 마모 테스트 챔버 시스템을 사용하여 주 : 마모 시험 조건을 표 2에 기재되어있다. <ol><li> 챔버의 중앙에 abrasor를 찾습니다. </li><li> abrasor의 표본 회전 무대에서 시험편을 설치합니다. </li><li> 시험편에 하중을 적용 할 1,000g 가중치 연마 휠 홀더에 마찰 바퀴를 고정. </li><li> 뉴트럴 라이저 (소프트 X 선 이오 나이저)를 찾습니다거리에 45 ° 각도로 시험편의 중심으로부터 28cm, 챔버 벽에 정전기 입자 침착을 감소시키기 위해,도 2에 도시 된 바와 같이. 주 : 중화제는 빔 노출에 의한 정전기력을 제거합니다. 공기 입구 마모 차륜 시험편 회전 스테이지 위에 배치되어 있기 때문에,이 시험편의 표면에 대한 중화제 빔의 액세스를 제한한다. 따라서, 중화제는 빔이 가능한 시료 표면의 정도에 도달 할 수 있도록 대각선으로 위치한다. </li><li> 50 L / min의 유량으로 챔버의 출구에 설치된 송풍기를 작동한다. </li><li> 공급 장치 (25) L / 분 추가 공기 유입구를 통해 공기 압축기를 사용하여 추가 무 입자 현탁액 공기. 주 : 마모에 의해 생성 된 입자가 강하게 시험편 마모 휠의 표면 상에 증착시켰다. 따라서, abrased 입자를 측정하기 어렵다. 추가 공기 유입구 그러는 수P 입자 현탁액이 문제를 해결한다. </li><li> 도 4에 기술 된 바와 같이, CPC를 사용 / 1 이하 CC의 1 시간 동안의 평균 입자 수 농도에 도달하기 위해 상기 챔버 내부의 배경 입자 수 농도를 확인한다. </li><li> 1000 회전으로 72 rpm에서 시험편 회전 스테이지를 회전시키는 스텝 모터를 사용하여 시험편의 abrasor 회전 스테이지를 동작한다. </li><li> 측정하고 CPC와 OPC를 사용하여 방출 입자 수 농도와 입도 분포를 기록한다. 참고 : 나노 복합 재료에서 방출 된 입자는 정지 및 펌핑되는 공기에 의해 수행된다. 이 부유 입자는 결국 기류 다음 출구로 이송된다. 방출 된 입자를 상기 챔버의 출구에서 CPC와 OPC에 의해 검출된다. OPC는 입도 분포를 측정 할 수있는 반면, CPC 및 OPC 자주 입자 수 농도를 측정하기 위해 사용된다. </li><li> SAMP제작 여과재 또는 TEM 그리드를 함유하는 입자 샘플러를 사용하여 공개 된 입자. 주 : 다음 기류 챔버의 출구에 마모 이동하여 나노 입자로부터 방출. 상기 챔버의 출구에서 방출 된 입자는 입자 샘플러를 사용하여 샘플링 될 수있다. 필터 매체 또는 TEM 그리드 상에 수집 된 입자를 방출 TEM 또는 SEM (주사 전자 현미경)을 이용하여 분석 될 수있다. </li><li> 입자 수 농도 아래의 피크의 입자 수 농도 0.1 %에 도달 할 때 측정 및 샘플링을 멈춘다. </li><li> 모든 데이터 (CPC, OPC)을 저장하고 모든 샘플 (시험편)를 제거합니다. </li><li> 각 시험에 새로운 시험편 및 신규 연마 휠을 사용하고, 챔버를 세척 및 재현성을 확인하기 위해 각각의 마모 시험 후의 매직 잉크를 킴 와이프와 IPA (이소 프로필 알코올)를 abrasor. </li></ol>

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The authors have nothing to disclose.

마모 시험을 이용하여 나노 물질의 nanorelease 테스트를 수행하는 가장 중요한 단계가 있었다 : 1)로 마찰에 의해 발생 된 정전기를 제거하고, 챔버 벽에 입자의 증착을 감소시키는 중화제와 스테인리스 챔버 시스템을 사용하는 단계; 2) 더 입자 현탁액을 제공하는 추가 공기를 공급하는 단계; 3) 세 공판 구성된 믹서를 포함 출구로부터 CPC와 OPC를 사용하여 입자 방출 및 온라인 모니터링 샘플링. <p...

소비자 노출이 광범위하게 연구되지 않은 상태에서 나노 물질의 노출은 주로 취급 제조 및 나노 물질을 포장, 제조 사업장에서 근로자 관련 연구되고있다. 나노 기술의 국제위원회 (ICON)에 의해 생성 된 환경과 건강 문헌 데이터베이스의 최근 분석은 또한 대부분의 나노 물질 안전성 연구가 나타내는, 나노 복합 재료의 출시와 함께, 위험 (83 %) 및 잠재적 인 노출 (16 %)에 초점을 맞춘 것으로 표시 0.8 % 1을 나타내는 소비자 노출. 따라서, 매우 작은 나노 물질에 대한 소비자 노출에 대한 알려져있다. 나노 입자 방출은 연마를 포함하고 나노 세척 직물, 또는 회전 드럼 법 등 DUSTINESS 시험 법, 선회 진탕있어서, 다른 교반기 방법 2-3의 내후성의 시뮬레이션 연구 소비자 노출을 평가하기 위해 사용되었다. 또한, 여러 국제예 ILSI (국제 생명 공학 연구원) nanorelease 및 EU NanoReg 같은 시도가 소비자 제품에 사용 된 나노 물질의 방출을 이해하는 기술을 개발하기위한 노력이 이루어지고있다. 2011 년에 시작된 ILSI nanorelease 소비자 제품은 1 단계는 나노 물질의 선택을 포함 소비자 제품에서 나노 물질 방출에 대한 라이프 사이클 접근 방식을 나타내고, 2 단계는 평가 방법을 포함하고, 3 단계는 실험실 간 연구를 구현합니다. 소비자 제품에 나노 물질의 안전성에 여러 논문 및 간행물도 4-6을 발표했다. 한편, NanoReg 제조 나노 물질의 규제 시험에 대한 일반적인 유럽 방식을 나타냅니다 및 시뮬레이션에 사용하기위한 방법의 프로그램 2. ISO TC 229는 소비자 안전과 관련된 표준을 개발하려고하는 소비자 제품에서 nanorelease 새를 제출 접근 제공 소비자 안전에 대한 작업 항목 제안. 경제 협력 개발기구 (OECD) WPMN (가공용나노 물질에 대한 자), 노출 평가 및 노출 완화에 특히 SG8 (스티어링 그룹) ng를, 최근 미래의 작업, 특히 소비자 및 환경 노출 평가의 방향에 대한 설문 조사를 실시했다. 따라서 이러한 국제 활동에 비추어, 무역, 산업 및 에너지의 한국 사역은 2013 년 계층화 된 프로젝트는 &quot;나노 물질과 나노 제품의 ​​안전성 평가 및 표준화 기술 개발&quot;에 초점을 시작했다. 또한, 여러 소비자 안전 관련 연구는 소비자 제품에서 나노 물질의 방출도 7-8 게시 된 표준화합니다. 마모 시험은 다른 상용 복합 제품의 나노 입자의 전위 배출 레벨을 결정하기위한 ILSI의 nanorelease NanoReg 및 2-3에 포함 된 시뮬레이션 방법 중 하나이다. 질량 감량 ABRAS 전과 후의 시료 중량의 차이에 기초하여 도출되고이온은 abrasor를 사용. 나노 복합 시료를 일정한 속도로 연마되고, 샘플러는 에어로졸을 흡입하고, 입자는 이러한 응축 입자 계수기 (CPC) 또는 광학 입자 계수기 (OPC) 등의 입자 계수 장치를 이용하여 분석하고, TEM에 수집 상기 영상 분석 (투과 전자 현미경) 그리드 또는 막. 그러나, 나노 복합 재료의 마모 시험을 실시하여 입자에 마모의 결과와 같이 충전 기인 어렵고 일관성있는 나노 입자 방출을 요구 입자 샘플링은 발광 점 2-3, 9-11 근처 행하는 경우. 따라서, 본 논문은 나노 복합 재료의 마모의 경우 나노 물질의 방출을 평가하기위한 새로운 방법으로 챔버 시스템을 제공합니다. 다른 마모 모의 실험과 비교할 때, 제안 챔버 시스템은 마모의 경우 일관 나노 해제 데이터를 제공한다. 또한,이 새로운 시험 방법전체 입자 수의 계산 방법 등 실내 공기질 세미 실시 산업 분야에서 널리 이용되고있다 (12, 13). 따라서, 제안 된 방법을 포함하는 소비자 제품에서 시험 나노 입자 방출을위한 표준화 된 방법으로 개발 될 수있는 것으로 예상된다 나노 물질.

<table><tbody><tr><td>Foamex</td><td>Taeyoung, R. of Korea</td><td></td><td></td></tr><tr><td>MWCNT (multiwalled carbon nanotube) composite</td><td>Hanwha, Incheon, R. of Korea</td><td></td><td>2% MWCNTs in low density polyethylene</td></tr><tr><td>Abrasion Paper</td><td>Derfos, R. of Korea</td><td>#100</td><td>100 grit sand paper</td></tr><tr><td>Condensation Particle Counter (CPC)</td><td>TSI Inc, Shoreview, MN</td><td>UCPC 3775</td><td></td></tr><tr><td>Optical Paritcle Counter (OPC)</td><td>Grimm, Ainring, Germany</td><td>1.109</td><td></td></tr><tr><td>Mini Particle Sampler</td><td>Ecomesure, Saclay, France</td><td></td><td></td></tr><tr><td>Quantifoil Holey Carbon Film</td><td>TED PELLA Inc. USA</td><td>1.2/1.3</td><td></td></tr><tr><td>Filter Holder</td><td></td><td></td><td>custom made</td></tr><tr><td>Polycarbonate Filter&amp;nbsp;</td><td>Millipore, USA</td><td>CAT No. GTTP02500</td><td></td></tr><tr><td>Soft X-ray Ionizer (Neutralizer)</td><td>SUNJE, R. of Korea</td><td>SXN-05U</td><td></td></tr><tr><td>Field Emission-Scanning Electron Microscope (FE-SEM)</td><td>Hitachi</td><td>S-4300</td><td></td></tr></tbody></table>

testing of nanoparticle release from a composite containing nanomaterial using a chamber system

21 세기에서 가장 중요한 기술 중 하나로서 나노 기술의 급속한 발전과 함께, 나노 물질을 포함하는 소비자 제품의 안전성에 대한 관심 또한 증가하고있다. 나노 물질을 함유하는 제품의 나노 물질 방출을 평가하여 이들 제품의 안전성을 평가하는 중요한 공정이며, 나노 물질의 방출의 평가를 표준화에 대한 일관되고 신뢰성있는 기술을 개발하기위한 여러 국제적 노력 가져왔다. 이 연구에서 나노 물질을 포함하는 제품에서 나노 물질의 방출은 전자 현미경 분석을위한 여과 된 샘플을 수집 포트를 응축 핵 계수기 광학 입자 계수기를 포함하는 챔버 시스템을 사용하고, 샘플을 평가 하였다. 제안 챔버 시스템은 나노 물질 방출이 허용되는 범위 내에서 반복과 일치 하는가를 결정하기 위해 abrasor 및 디스크 형 나노 복합 재료의 시험편을 사용하여 시험한다.시험 결과는 각 시험에서 입자의 갯수가 여러 시험 후 평균에서 20 % 이내 인 것을 나타낸다. 릴리스 경향은 비슷합니다 그들은 아주 좋은 반복성을 보여줍니다. 따라서, 제안 된 챔버 시스템은 효과적으로 나노 물질을 함유하는 제품의 나노 박리 테스트에 사용될 수있다.

마모 테스트 반복성은 챔버 시스템을 사용하여 OPC는 1.98 × 109 입자 (&gt; 0.3 μm의) 평균을 계산하는 동안 표 3에 나타낸 바와 같이 전체 입자 수는 8 마모 시험 일치 하였다. CPC는 3.67 X10 구 입자의 평균을 측정 하였다. 편차는 마모 동안 입자의 일관된 릴리스를 대표 20 % 이내였다. <p class="jove_step" fo:...

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Testing of Nanoparticle Release from a Composite Containing Nanomaterial Using a Chamber System

Nanoparticle release is tested using a chamber system that includes a condensation particle counter, an optical particle counter and sampling ports to collect filter samples for microscopy analysis. The proposed chamber system can be effectively used for nanomaterial release testing with a repeatable and consistent data range.

재판부 시스템을 사용하여 나노 재료를 포함하는 복합에서 나노 입자 릴리스의 테스트

With the rapid development of nanotechnology as one of the most important technologies in the 21st century, interest in the safety of consumer products ...

testing-nanoparticle-release-from-composite-containing-nanomaterial

Research

JoVE Journal

Engineering

6.7K 조회수.  Hanyang University. Nanoparticle release is tested using a chamber system that includes a condensation particle counter, an optical particle counter and sampling ports to collect filter samples for microscopy analysis. The proposed chamber system can be effectively used for nanomaterial release testing with a repeatable and consistent data range.

비디오: Testing of Nanoparticle Release from a Composite Containing Nanomaterial Using a Chamber System

Optical Trapping of Nanoparticles

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping and manipulating small biological particles. Ashkin and co-workers first demonstrated optical tweezers using a single focused beam1. The single beam trap can be described accurately using the perturbative gradient force formulation in the case of small Rayleigh regime particles1. In the perturbative regime, the optical power required for trapping a particle scales as the inverse fourth power of the particle size. High optical powers can damage dielectric particles and cause heating. For instance, trapped latex spheres of 109 nm in diameter were destroyed by a 15 mW beam in 25 sec1, which has serious implications for biological matter2,3.
A self-induced back-action (SIBA) optical trapping was proposed to trap 50 nm polystyrene spheres in the non-perturbative regime4. In a non-perturbative regime, even a small particle with little permittivity contrast to the background can influence significantly the ambient electromagnetic field and induce a large optical force. As a particle enters an illuminated aperture, light transmission increases dramatically because of dielectric loading. If the particle attempts to leave the aperture, decreased transmission causes a change in momentum outwards from the hole and, by Newton's Third Law, results in a force on the particle inwards into the hole, trapping the particle. The light transmission can be monitored; hence, the trap can become a sensor. The SIBA trapping technique can be further improved by using a double-nanohole structure.
The double-nanohole structure has been shown to give a strong local field enhancement5,6. Between the two sharp tips of the double-nanohole, a small particle can cause a large change in optical transmission, thereby inducing a large optical force. As a result, smaller nanoparticles can be trapped, such as 12 nm silicate spheres7 and 3.4 nm hydrodynamic radius bovine serum albumin proteins8. In this work, the experimental configuration used for nanoparticle trapping is outlined. First, we detail the assembly of the trapping setup which is based on a Thorlabs Optical Tweezer Kit. Next, we explain the nanofabrication procedure of the double-nanohole in a metal film, the fabrication of the microfluidic chamber and the sample preparation. Finally, we detail the data acquisition procedure and provide typical results for trapping 20 nm polystyrene nanospheres.

The following setup approach details low power optical trapping of dielectric nanoparticles using a double-nanohole in metal film.

나노 입자의 광학 트래핑

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping ...

연구

공학

Combinatorial Synthesis of and High-throughput Protein Release from Polymer Film and Nanoparticle Libraries

Polyanhydrides are a class of biomaterials with excellent biocompatibility and drug delivery capabilities. While they have been studied extensively with conventional one-sample-at-a-time synthesis techniques, a more recent high-throughput approach has been developed enabling the synthesis and testing of large libraries of polyanhydrides1. This will facilitate more efficient optimization and design process of these biomaterials for drug and vaccine delivery applications. The method in this work describes the combinatorial synthesis of biodegradable polyanhydride film and nanoparticle libraries and the high-throughput detection of protein release from these libraries. In this robotically operated method (Figure 1), linear actuators and syringe pumps are controlled by LabVIEW, which enables a hands-free automated protocol, eliminating user error. Furthermore, this method enables the rapid fabrication of micro-scale polymer libraries, reducing the batch size while resulting in the creation of multivariant polymer systems. This combinatorial approach to polymer synthesis facilitates the synthesis of up to 15 different polymers in an equivalent amount of time it would take to synthesize one polymer conventionally. In addition, the combinatorial polymer library can be fabricated into blank or protein-loaded geometries including films or nanoparticles upon dissolution of the polymer library in a solvent and precipitation into a non-solvent (for nanoparticles) or by vacuum drying (for films). Upon loading a fluorochrome-conjugated protein into the polymer libraries, protein release kinetics can be assessed at high-throughput using a fluorescence-based detection method (Figures 2 and 3) as described previously1. This combinatorial platform has been validated with conventional methods2 and the polyanhydride film and nanoparticle libraries have been characterized with 1H NMR and FTIR. The libraries have been screened for protein release kinetics, stability and antigenicity; in vitro cellular toxicity, cytokine production, surface marker expression, adhesion, proliferation and differentiation; and in vivo biodistribution and mucoadhesion1-11. The combinatorial method developed herein enables high-throughput polymer synthesis and fabrication of protein-loaded nanoparticle and film libraries, which can, in turn, be screened in vitro and in vivo for optimization of biomaterial performance.

This method describes the combinatorial synthesis of biodegradable polyanhydride film and nanoparticle libraries and the high-throughput detection of protein release from these libraries.

조합의 합성과 고분자 필름과 Nanoparticle 도서관에서 높은 처리량 단백질 출시

Polyanhydrides are a class of biomaterials with excellent biocompatibility and drug delivery capabilities. While they have been studied extensively with ...

생체공학

Experimental Protocol to Investigate Particle Aerosolization of a Product Under Abrasion and Under Environmental Weathering

The present article presents an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental weathering, which is a fundamental element to the approach of nanosafety-by-design of nanostructured products for their durable development. This approach is basically a preemptive one in which the focus is put on minimizing the emission of engineered nanomaterials' aerosols during the usage phase of the product's life cycle. This can be attained by altering its material properties during its design phase without compromising with any of its added benefits. In this article, an experimental protocol is presented to investigate the nanosafety-by-design of three commercial nanostructured products with respect to their mechanical solicitation and environmental weathering. The means chosen for applying the mechanical solicitation is an abrasion process and for the environmental weathering, it is an accelerated UV exposure in the presence of humidity and heat. The eventual emission of engineered nanomaterials is studied in terms of their number concentration, size distribution, morphology and chemical composition. The purpose of the protocol is to study the emission for test samples and experimental conditions which are corresponding to real life situations. It was found that the application of the mechanical stresses alone emits the engineered nanomaterials' aerosols in which the engineered nanomaterial is always embedded inside the product matrix, thus, a representative product element. In such a case, the emitted aerosols comprise of both nanoparticles as well as microparticles. But if the mechanical stresses are coupled with the environmental weathering, the experimental protocol reveals then the eventual deterioration of the product, after a certain weathering duration, may lead to the emission of the free engineered nanomaterial aerosols too.

In this article, an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental weathering is presented. Results on the emission of engineered nanomaterials, in the form of aerosols are presented. The specific experimental set-up is described in detail.

실험 프로토콜 마모에서 환경 풍화에서 제품의 입자 에어로졸을 조사하기

The present article presents an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental ...

Evaluation of Polymeric Gene Delivery Nanoparticles by Nanoparticle Tracking Analysis and High-throughput Flow Cytometry

Non-viral gene delivery using polymeric nanoparticles has emerged as an attractive approach for gene therapy to treat genetic diseases1 and as a technology for regenerative medicine2. Unlike viruses, which have significant safety issues, polymeric nanoparticles can be designed to be non-toxic, non-immunogenic, non-mutagenic, easier to synthesize, chemically versatile, capable of carrying larger nucleic acid cargo and biodegradable and/or environmentally responsive. Cationic polymers self-assemble with negatively charged DNA via electrostatic interaction to form complexes on the order of 100 nm that are commonly termed polymeric nanoparticles. Examples of biomaterials used to form nanoscale polycationic gene delivery nanoparticles include polylysine, polyphosphoesters, poly(amidoamines)s and polyethylenimine (PEI), which is a non-degradable off-the-shelf cationic polymer commonly used for nucleic acid delivery1,3 . Poly(beta-amino ester)s (PBAEs) are a newer class of cationic polymers4 that are hydrolytically degradable5,6 and have been shown to be effective at gene delivery to hard-to-transfect cell types such as human retinal endothelial cells (HRECs)7, mouse mammary epithelial cells8, human brain cancer cells9 and macrovascular (human umbilical vein, HUVECs) endothelial cells10.
A new protocol to characterize polymeric nanoparticles utilizing nanoparticle tracking analysis (NTA) is described. In this approach, both the particle size distribution and the distribution of the number of plasmids per particle are obtained11. In addition, a high-throughput 96-well plate transfection assay for rapid screening of the transfection efficacy of polymeric nanoparticles is presented. In this protocol, poly(beta-amino ester)s (PBAEs) are used as model polymers and human retinal endothelial cells (HRECs) are used as model human cells. This protocol can be easily adapted to evaluate any polymeric nanoparticle and any cell type of interest in a multi-well plate format.

A protocol for nanoparticle tracking analysis (NTA) and high-throughput flow cytometry to evaluate polymeric gene delivery nanoparticles is described. NTA is utilized to characterize the nanoparticle particle size distribution and the plasmid per particle distribution. High-throughput flow cytometry enables quantitative transfection efficacy evaluation for a library of gene delivery biomaterials.

고분자 유전자 배달에 대한 평가는 Nanoparticle 추적 분석 및 높은 처리량 유동 세포 계측법에 의해 나노 입자

Non-viral gene delivery using polymeric nanoparticles has emerged as an attractive approach for gene therapy to treat genetic diseases1 and as a ...

Advanced Compositional Analysis of Nanoparticle-polymer Composites Using Direct Fluorescence Imaging

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise composition of these materials is essential, especially in the design of surface catalysts, where the surface concentration of the active component determines the activity of the material. Antimicrobial materials which utilize nanoparticles are a particular focus of this technology. Recently swell encapsulation has emerged as a technique for inserting antimicrobial nanoparticles into a host polymer matrix. Swell encapsulation provides the advantage of localizing the incorporation to the external surfaces of materials, which act as the active sites of these materials. However, quantification of this nanoparticle uptake is challenging. Previous studies explore the link between antimicrobial activity and surface concentration of the active component, but this is not directly visualized. Here we show a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of CdSe/ZnS nanoparticles can be accurately visualized through cross-sectional fluorescence imaging. Using this method, we can quantify the uptake of nanoparticles via swell encapsulation and measure the surface concentration of encapsulated particles, which is key in optimizing the activity of functional materials.

Here we present a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of cadmium selenide quantum dots can be accurately visualized through cross-sectional fluorescence imaging.

직접 형광 이미징을 사용하여 나노 입자 - 고분자 복합 재료의 고급 성분 분석

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise ...

A System to Create Stable Nanoparticle Aerosols from Nanopowders

Nanoparticle aerosols released from nanopowders in workplaces are associated with human exposure and health risks. We developed a novel system, requiring minimal amounts of test materials (min. 200 mg), for studying powder aerosolization behavior and aerosol properties. The aerosolization procedure follows the concept of the fluidized-bed process, but occurs in the modified volume of a V-shaped aerosol generator. The airborne particle number concentration is adjustable by controlling the air flow rate. The system supplied stable aerosol generation rates and particle size distributions over long periods (0.5-2 hr and possibly longer), which are important, for example, to study aerosol behavior, but also for toxicological studies. Strict adherence to the operating procedures during the aerosolization experiments ensures the generation of reproducible test results. The critical steps in the standard protocol are the preparation of the material and setup, and the aerosolization operations themselves. The system can be used for experiments requiring stable aerosol concentrations and may also be an alternative method for testing dustiness. The controlled aerosolization made possible with this setup occurs using energy inputs (may be characterized by aerosolization air velocity) that are within the ranges commonly found in occupational environments where nanomaterial powders are handled. This setup and its operating protocol are thus helpful for human exposure and risk assessment.

We designed and developed an effective nanopowder aerosolization setup and operating protocol. The system generated nanoparticle aerosols with stable number concentrations and size distributions for long durations, requiring only small quantities of test material (min. 200 mg).

시스템은 나노 분말에서 안정적인 나노 입자 에어로졸을 만드는 방법

Nanoparticle aerosols released from nanopowders in workplaces are associated with human exposure and health risks. We developed a novel system, requiring ...

A Continuous-flow Photocatalytic Reactor for the Precisely Controlled Deposition of Metallic Nanoparticles

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic nanoparticles is developed. Guidelines for the replication of the reactor and its operation are provided in detail. Three different composite systems (Pt/graphene, Pt/TiO2, and Au/TiO2) with monodisperse and uniformly distributed particles are produced by this reactor, and the photodeposition mechanism, as well as the synthesis optimization strategy, are discussed. The synthesis methods and their technical aspects are described comprehensively. The role of the ultraviolet (UV) dose (in each excitation pulse) on the photodeposition process is investigated and the optimum values for each composite system are provided.

For a continuous and scalable synthesis of noble-metal-based nanocomposites, a novel photocatalytic reactor is developed and its structure, operation principles, and product quality optimization strategies are described.

금속 나노 입자의 정확 하 게 제어 증 착에 대 한 연속 흐름 촉매 반응 기

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic ...

화학

Development of a Nose-only Inhalation Toxicity Test Chamber That Provides Four Exposure Concentrations of Nano-sized Particles

Using a numerical analysis based on computerized fluid dynamics, a nose-only inhalation toxicity chamber with four different exposure concentrations is designed and validated for flow field uniformity and cross-contamination among the exposure ports for each concentration. The designed flow field values are compared with the measured values from exposure ports located horizontally and vertically. For this purpose, nanoscale sodium chloride particles are generated as test particles and introduced to the inhalation chamber to evaluate the cross-contamination and concentration maintenance among the chambers, for each concentration group. The results indicate that the designed multiconcentration inhalation chamber can be used in animal inhalation toxicity testing without cross-contamination among concentration groups. Moreover, the designed multiconcentration inhalation toxicity chamber can also be converted to a single-concentration inhalation chamber. Further testing with gas, organic vapor, or non-nanoscale particles will ensure the use of the chamber in the inhalation testing of other test articles.

A nose-only inhalation toxicity chamber capable of testing inhalation toxicity at four different exposure concentrations was designed and validated for flow field uniformity and cross-contamination between the exposure ports for each concentration. Here, we present a protocol to confirm that the designed chamber is effective for inhalation toxicity testing.

나노 크기의 입자의 4 개의 노출 농도 제공 하는 코 전용 흡입 독성 시험 챔버의 개발

Using a numerical analysis based on computerized fluid dynamics, a nose-only inhalation toxicity chamber with four different exposure concentrations is ...

Whole-Body Nanoparticle Aerosol Inhalation Exposures

Inhalation is the most likely exposure route for individuals working with aerosolizable engineered nano-materials (ENM). To properly perform nanoparticle inhalation toxicology studies, the aerosols in a chamber housing the experimental animals must have: 1) a steady concentration maintained at a desired level for the entire exposure period; 2) a homogenous composition free of contaminants; and 3) a stable size distribution with a geometric mean diameter &lt; 200 nm and a geometric standard deviation &sigma;g &lt; 2.5 5. The generation of aerosols containing nanoparticles is quite challenging because nanoparticles easily agglomerate. This is largely due to very strong inter-particle forces and the formation of large fractal structures in tens or hundreds of microns in size 6, which are difficult to be broken up. Several common aerosol generators, including nebulizers, fluidized beds, Venturi aspirators and the Wright dust feed, were tested; however, none were able to produce nanoparticle aerosols which satisfy all criteria 5.
A whole-body nanoparticle aerosol inhalation exposure system was fabricated, validated and utilized for nano-TiO2 inhalation toxicology studies. Critical components: 1) novel nano-TiO2 aerosol generator; 2) 0.5 m3 whole-body inhalation exposure chamber; and 3) monitor and control system. Nano-TiO2 aerosols generated from bulk dry nano-TiO2 powders (primary diameter of 21 nm, bulk density of 3.8 g/cm3) were delivered into the exposure chamber at a flow rate of 90 LPM (10.8 air changes/hr). Particle size distribution and mass concentration profiles were measured continuously with a scanning mobility particle sizer (SMPS), and an electric low pressure impactor (ELPI). The aerosol mass concentration (C) was verified gravimetrically (mg/m3). The mass (M) of the collected particles was determined as M = (Mpost-Mpre), where Mpre and Mpost are masses of the filter before and after sampling (mg). The mass concentration was calculated as C = M/(Q*t), where Q is sampling flowrate (m3/min), and t is the sampling time (minute). The chamber pressure, temperature, relative humidity (RH), O2 and CO2 concentrations were monitored and controlled continuously. Nano-TiO2 aerosols collected on Nuclepore filters were analyzed with a scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis.
In summary, we report that the nano-particle aerosols generated and delivered to our exposure chamber have: 1) steady mass concentration; 2) homogenous composition free of contaminants; 3) stable particle size distributions with a count-median aerodynamic diameter of 157 nm during aerosol generation. This system reliably and repeatedly creates test atmospheres that simulate occupational, environmental or domestic ENM aerosol exposures.

A whole-body nanoparticle aerosol inhalation exposure facility was constructed for nano-sized titanium dioxide (TiO2) inhalation toxicology studies. This system provides nano-TiO2 aerosol test atmospheres that have: 1) a steady mass concentration; 2) a homogenous composition free of contaminants; and 3) a stable particle size distribution during aerosol generation.

전신 나노 입자 에어로졸 흡입 노출

Inhalation is the most likely exposure route for individuals working with aerosolizable engineered nano-materials (ENM). To properly perform nanoparticle ...

생물학

An Air-liquid Interface Bronchial Epithelial Model for Realistic, Repeated Inhalation Exposure to Airborne Particles for Toxicity Testing

For toxicity testing of airborne particles, air-liquid interface (ALI) exposure systems have been developed for in vitro tests in order to mimic realistic exposure conditions. This puts specific demands on the cell culture models. Many cell types are negatively affected by exposure to air (e.g., drying out) and only remain viable for a few days. This limits the exposure conditions that can be used in these models: usually relatively high concentrations are applied as a cloud (i.e., droplets containing particles, which settle down rapidly) within a short period of time. Such experimental conditions do not reflect realistic long-term exposure to low concentrations of particles. To overcome these limitations the use of a human bronchial epithelial cell line, Calu-3 was investigated. These cells can be cultured at ALI conditions for several weeks while retaining a healthy morphology and a stable monolayer with tight junctions. In addition, this bronchial model is suitable for testing the effects of repeated exposures to low, realistic concentrations of airborne particles using an ALI exposure system. This system uses a continuous airflow in contrast to other ALI exposure systems that use a single nebulization producing a cloud. Therefore, the continuous flow system is suitable for repeated and prolonged exposure to airborne particles while continuously monitoring the particle characteristics, exposure concentration, and delivered dose. Taken together, this bronchial model, in combination with the continuous flow exposure system, is able to mimic realistic, repeated inhalation exposure conditions that can be used for toxicity testing.

Described is the cell culture and exposure method of an in vitro bronchial model for realistic, repeated inhalation exposure to particles for toxicity testing.

독성 테스트를 위해 공기 중 입자에 대한 사실적이고 반복적인 흡입 노출을 위한 공기 액체 인터페이스 기관지 상피 모델

For toxicity testing of airborne particles, air-liquid interface (ALI) exposure systems have been developed for in vitro tests in order to mimic realistic ...