[nanoPost] Portable Real-Time Nano-Particle Analyser

University UK

Environmental monitoring.

1. Study on occupational health effects.
2. Drug delivery studies, e.g. Potential for non-invasive delivery of insulin?
3. Study and improvement of environmental conditions in civil aviation.
4. Improvements of environmental conditions in the workplace.
5. Applications in material science.

 Applicability:

As highlighted in the Royal Society Reports, one of the main problems in the area of environmental health studies and the potentially numerous use of nano technology is the absence of a real-time nano particle analyser.  Existing methodologies such as the use of Transmission Electron Microscope (TEM), Atomic Force Microscope (AFM) are very expensive and cannot be used in field studies or for continuous monitoring.  Other particulate analysers are also very expensive and some are bulky and cannot produce particulate imaging, does not work in real time, require expensive regular calibration and are not reliable.

It is clear from the aforementioned opportunities that the development of nanometrology as proposed in this work will enable applications that were not feasible with present technology, thereby allowing furtherance of scientific investigation and development of new and diverse technology.

The program will be initially developed and executed by a consortium of collaborators , where there are a broad range of facilities available for experimentation, development and testing of various phases of the project under field operational conditions

Risk and Challenge:

Real-time monitoring of nano-scale particles requires a range of capabilities, presently unavailable with any existing methodologies.  These include:

1. Instantaneous and continuous sampling capability of atmospheric particles.
2. Real-time measurement and particulate analysis.
3. Provision of self calibration

Ability to create Instantaneous and continuous sampling capabilities is a very challenging task in practice.  Once a sample is acquired, the system has to be completely free from particles from the previous sample.  As would be described later, in the present approach, particles are deposited by electrostatic fields, which are then held at the sampling window by Vander Wall’s forces.  After instantaneous measurements (also described later) we wish to remove these particles instantly by means of Surface Acoustic Waves (SAW) or ultrasonic sheer waves together with the application of AC fields within the sample volume, so that the particles are carried away by the incoming samples.

1.             Particle size pre-selector:

The function of Particle Pre-selector would be to avoid the entry of macro-particles out with the required range of measurement.  This is to be achieved by a combination of conventional filtering and if necessary, mass-selective electrostatic isolation.

2.             Ionisation chamber:

The pre-filtered sample will then be given a prescribed dosage of electrostatic charge by one or a combination of methods such as high voltage ion streaming or by a weak α source (such as that used in domestic smoke alarms).  A post selection of particles may also be carried out at this stage based on charge/mass (c/m) ratios within a static electric field.

3.             Particle analyser stage:

An interesting feature of this evanescent field is that the scattering produced by particles could be imaged with optical microscopy at sub-wavelength resolution as fluorescent images, which is not feasible with normal microscopic illumination or viewing.  

4.             Processing and Display

The display 4 would consist of an optical image of the scattering particles and the respective spectral features of the particles in contact with the interface.  At this stage all images and features will be analysed and displayed.   This stage therefore consists of an optical image display and hardware and software for characteristic particulate signature analysis.

5.             Coupling of the switchable DC and AC fields:

This is another important novel aspect that is critical for real-time operation which we wish to investigate and develop.  The potential applications of this would be extensive apart from the immediate improvements in the existing SPR studies in various scientific endeavours.