Synthesis and spectral properties of novel Singapore Green analogues for protease detection

Herein we describe the synthesis, characterisation and determination of fluorescence and photophysical properties of various novel analogues of the orphan fluorophore class Singapore Green. We equate the fluorescence properties of these novel fluorophores to their molecular structure and address the mechanisms through which their fluorescence is quenched and the effect this has on their quantum yields of fluorescence. Fluorescence quenching via acylation was also achieved, thereby providing conceptual proof of their utility as cores for future fluorescent probes. Additionally, we have produced and examined a number of unexpected acyl intermediates of variable photolytic stability. Furthermore, we have obtained proof of concept that the use of Singapore Greens for protease probe generation is feasible via demonstration of proteolytic cleavage of one of the acylated analogues

Investigation of fluorophore motifs for protease detection

There is an increasing and serious problem of antimicrobial resistance emerging where previously useful antibiotics are no longer effective. This causes a significant monetary and human cost in the healthcare system, and is a direct result of the misuse and over prescription of antibiotics. The development and implementation of rapid point of care diagnostics to conclusively identify problem pathogens such as 'Staphylococcus aureus' could slow the emergence of antibiotic resistance by correctly targeted antibiotic therapy. The rapid and sensitive protease detecting LGX probe is an example of such a diagnostic test. The synthesis of this rhodamine based fluorogenic probe and the investigation of other fluorescence motifs for protease detection has been the focus of this project. Scale up and optimisation of the synthetic route to the previously produced LGX probe was achieved, allowing further testing in a healthcare environment. Previous work has failed to address the complexities associated with the use of conventional fluorescence motifs for probe generation, as well as the ways in which their fluorescence may be modulated. Herein we address these problems, and those encountered with the scale up of the ‘LGX’ probe. The lessons learned from the LGX synthesis provided the basis for development of a number of novel analogues of the orphan fluorophore class Singapore Green. A library of nine simplified and highly active fluorescent Singapore Greens were generated. These were exhaustively investigated and it was determined how structural variations effect both their spectral and fluorescence properties including quantum yield and extinction coefficient. The spectral characteristics of Singapore Green fluorescent motifs were found to be highly favourable allowing them to provide the central core of future probes. This work has also provided the synthetic methodology required to produce ‘LGX’ in the quantities required for eventual utilisation in healthcare environments. Furthermore it has provided the several novel platforms for the development of future probes. This is of potentially considerable value as it may not only contribute to the reduction of the problem pathogen 'S. aureus' as well as slow the emergence of resistance, but also facilitate generation of other important protease detection systems

The effects of social service contact on teenagers in England

Objective: This study investigated outcomes of social service contact during teenage years. Method: Secondary analysis was conducted of the Longitudinal Survey of Young People in England (N = 15,770), using data on reported contact with social services resulting from teenagers’ behavior. Outcomes considered were educational achievement and aspiration, mental health, and locus of control. Inverse-probability-weighted regression adjustment was used to estimate the effect of social service contact. Results: There was no significant difference between those who received social service contact and those who did not for mental health outcome or aspiration to apply to university. Those with contact had lower odds of achieving good exam results or of being confident in university acceptance if sought. Results for locus of control were mixed. Conclusions: Attention is needed to the role of social services in supporting the education of young people in difficulty. Further research is needed on the outcomes of social services contact