SUMMARYPeakForce TM Quantitative Nanomechanical Mapping (QNM TM ) is a new atomic force microscopy technique for measuring the Young's modulus of materials with high spatial resolution and surface sensitivity, by probing at the nanoscale. In the present work, modulus results from PeakForce™ QNM™ using three different probes are presented for a number of different polymers with a range of Young's moduli that were measured independently by Instrumented (nano) Indentation Testing (IIT). The results from the diamond and silicon AFM probes were consistent and in reasonable agreement with IIT values for the majority of samples. It is concluded that the technique is complimentary to IIT; calibration requirements and potential improvements to the technique are discussed.

Dielectrophoresis (DEP) offers many advantages over conventional cell assays such as flow cytometry and patch clamp techniques for assessing cell electrophysiology as a marker for cancer studies and drug interaction assessment. However, despite the advantages offered by DEP analysis, uptake has been low, remaining largely in the academic arena, due to the process of analysis being time-consuming, laborious, and ultimately allowing only serial analysis on small numbers of cells. In this paper we describe a new method of performing DEP analysis based on laminate manufacturing methods. These use a three-dimensional “well” structure, similar in size and pitch to conventional microtiter well plates, but offer electrodes along the inner surface to allow easy measurement of cell properties through the whole population. The result can then be determined rapidly using a conventional well-plate reader. The nature of the device means that many electrodes, each containing a separate sample, can be tested in parallel, while the mode of observation means that analysis can be combined with simultaneous measurement of conventional fluorimetric well-based assays. Here we benchmark the device against standard DEP assays, then show how such a device can be used to (a) rapidly determine the effects both of ion channel blockers on cancer cells and antibiotics on bacteria and (b) determine the properties of multiple subpopulations of cells within a well simultaneously.

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Adhesively bonded composite-composite single-lap joints, with cross-ply GFRP adherends, have been cyclically loaded to initiate disbonding at either end of the overlap length. Disbond initiation and growth have been monitored using a combination of in situ photography (the joint is transparent) and a single chirped fibre Bragg grating (CFBG) sensor embedded within one composite adherend (with the low-wavelength end of the sensor adjacent to the cut end) and not in the adhesive bondline. Sensors having the same spectral bandwidth (20 nm), and lengths in the range 15 mm to 60 mm have been tested. The experimental results have been modelled using a combination of finite-element analysis and commercial software for predicting FBG spectra, and the predictions are in very good agreement with the experimental results. In all cases, it has been shown that the position of the disbond front can be located using the CFBG sensors with a precision of about 2 mm.