Fluorophore unmixing based on bleaching and recovery kinetics using MCR-ALS.

Fluorescence microscopy is a key technology in the life sciences, though its performance is constrained by the number of labels that can be recorded. We propose to use the kinetics of fluorophore photodestruction and subsequent fluorescence recovery to distinguish multiple spectrally-overlapping emitters in fixed cells, thus enhancing the information that can be obtained from a single measurement. We show that the data can be directly processed using multivariate curve resolution - alternating least squares (MCR-ALS) to deliver distinct images for each fluorophore in their local environment, and apply this methodology to membrane imaging using DiBAC4(3) and concanavalin A - Alexa Fluor 488 as the fluorophores. We find that the DiBAC4(3) displays two distinct degradation/recovery kinetics that correspond to two different label distributions, allowing us to simultaneously distinguish three different fluorescence distributions from two spectrally overlapping fluorophores. We expect that our approach will scale to other dynamically-binding dyes, leading to similarly increased multiplexing capability.

Superhydrophobic polypyrene films to prevent Staphylococcus aureus and Pseudomonas aeruginosa biofilm adhesion on surfaces: high efficiency deciphered by fluorescence microscopy.

A blue luminescent and superhydrophobic coating based on an electropolymerized fluorinated-pyrene monomer and its planktonic bacteria and biofilm repellent properties are reported. Two different pathogenic bacterial strains (Gram-positive and Gram-negative) at two different incubation times (2 h planktonic bacterial and 24 h biofilm adhesion) were studied and monitored (analyzed) using multicolor scanning confocal fluorescence microscopy. The coating was proved to reduce bacterial adhesion by 65%. It is highly effective against biofilm attachment, with 90% reduction of bacteria surface coverage. This blue fluorescent surface provides a facile method to characterize the coating, observe the bacterial distribution and quantify the bacterial coverage rate by fluorescence imaging of different colors. Furthermore, the film does not show significant bacterial toxicity during the working incubation times.

Physical-chemical treatment of rainwater runoff in recovery and recycling companies: lab-scale investigation.

Scrap material recovery and recycling companies are producing wastewater in which common pollutants (such as COD, nutrients and suspended solids), toxic metals, polyaromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) frequently can exceed the discharge limits. Lab-scale optimisation of different possible physical-chemical treatment techniques was performed on the wastewater originating from three different companies in view of further testing at pilot-scale testing and implementation at full-scale. The lab-scale tests demonstrate that sedimentation or hydrocyclone treatment as stand-alone technique cannot be used for proper treatment of this type of wastewater. Dual bed filtration or coagulation/flocculation proved to be more promising with removal efficiencies of about 71-95% (dual bed filtration) and 61-97% (coagulation/flocculation) for the above-mentioned pollutants (metals, PAH and PCB).