An integrated multi-wavelength SCATTIRSTORM microscope combining TIRFM and IRM modalities for imaging cellulases and other processive enzymes

We describe a multimodal SCATTIRSTORM microscope for visualizing processive enzymes moving on immobilized substrates. The instrument combines Interference Reflection Microscopy (IRM) with multi-wavelength Total Internal Reflectance Fluorescence Microscopy (TIRFM). The microscope can localize quantum dots with a precision of 2.8 nm at 100 frames/s, and was used to image the dynamics of the cellulase, Cel7a interacting surface-immobilized cellulose. The instrument, which was built with off-the-shelf components and controlled by custom software, is suitable for tracking other degradative enzymes such as collagenases, as well as motor proteins moving along immobilized tracks.

Incorporation of FGF-2 into Pharmaceutical Grade Fucoidan/Chitosan Polyelectrolyte Multilayers

Biopolymer polyelectrolyte multilayers are a commonly studied soft matter system for wound healing applications due to the biocompatibility and beneficial properties of naturally occurring polyelectrolytes. In this work, a popular biopolymer, chitosan, was combined with the lesser known polysaccharide, fucoidan, to create a multilayer film capable of sequestering growth factor for later release. Fucoidan has been shown to act as a heparin-mimic due to similarities in the structure of the two molecules, however, the binding of fibroblast growth factor-2 to fucoidan has not been demonstrated in a multilayer system. This study assesses the ability of fucoidan to bind fibroblast growth factor-2 within a fucoidan/chitosan polyelectrolyte multilayer structure using attenuated total internal reflectance infrared spectroscopy and quartz crystal microbalance with dissipation monitoring. The fibroblast growth factor-2 was sequestered into the polyelectrolyte multilayer as a cationic layer in the uppermost layers of the film structure. In addition, the diffusion of fibroblast growth factor-2 into the multilayer has been assessed.

Circular Gabor wavelet algorithm for fingerprint liveness detection

Biometrics usage is growing daily and fingerprint-based recognition system is among the most effective and popular methods of personality identification. The conventional fingerprint sensor functions on total internal reflectance (TIR), which is a method that captures the external features of the finger that is presented to it. Hence, this opens it up to spoof attacks. Liveness detection is an anti-spoofing approach that has the potentials to identify physiological features in fingerprints. It has been demonstrated that spoof fingerprint made of gelatin, gummy and play-doh can easily deceive sensor. Therefore, the security of such sensor is not guaranteed. Here, we established a secure and robust fake-spoof fingerprint identification algorithm using Circular Gabor Wavelet for texture segmentation of the captured images. The samples were exposed to feature extraction processing using circular Gabor wavelet algorithm developed for texture segmentations. The result was evaluated using FAR which measures if a user presented is accepted under a false claimed identity. The FAR result was 0.03125 with an accuracy of 99.968% which showed distinct difference between live and spoof fingerprint.

‘Simultaneous tracking of cell motility in liquid and at the solid-liquid interface’

1.AbstractTo better understand key behaviors of living cells, such as bacterial biofilm formation, they must be observed above surfaces and at the interface between the surface and liquid medium. We have established a methodology for label-free imaging and tracking of individual cells simultaneously at both the solid-liquid interface and within the bulk, utilizing imaging modes of digital holographic microscopy (DHM) in 3D, differential interference contrast (DIC) and total internal reflectance microscopy (TIRM) in 2D as well as analysis protocols using a bespoke software package. We illustrate the power of this method by making detailed single cell measurements ofPseudomonas aeruginosain the first minutes of their interaction with a glass surface, focusing on the role of the flagella stators,motABandmotCD. Using this new method we have determined their relative contributions to bulk and near surface motion for populations of cells at the single cell level.

Adsorption of Alcohols onto Zinc Selenide (ZnSe) Crystal Surface

Adsorption behaviour of ZnSe, a popular material used in the manufacture of crystals for total internal reflectance techniques was studied for the adsorption of alcohols from dichloromethane solutions using infrared spectrometry. A series of n-alcohols were used in this study. The results show that the integrated area for the hydrogen bonded OH stretchings decrease and suggests that there is a continuous adsorption of alcohol molecules onto the ZnSe crystal by breaking the hydrogen bonds between alcohol molecules in solution.