Combining Whispering-Gallery Mode Optical Biosensors with Microfluidics for Real-Time Detection of Protein Secretion from Living Cells in Complex Media

The noninvasive monitoring of protein secretion of cells responding to drug treatment is an effective and essential tool in latest drug development and for cytotoxicity assays. In this work, a surface functionalization method is demonstrated for specific detection of protein released from cells and a platform that integrates highly sensitive optical devices, called whispering-gallery mode biosensors, with precise microfluidics control to achieve label-free and real-time detection. Cell biomarker release is measured in real time and with nanomolar sensitivity. The surface functionalization method allows for antibodies to be immobilized on the surface for specific detection, while the microfluidics system enables detection in a continuous flow with a negligible compromise between sensitivity and flow control over stabilization and mixing. Cytochrome c detection is used to illustrate the merits of the system. Jurkat cells are treated with the toxin staurosporine to trigger cell apoptosis and cytochrome c released into the cell culture medium is monitored via the newly invented optical microfluidic platform.

A 4-year retrospective clinical study of Class I and Class II composite restorations

OBJECTIVES

The purpose of this study was to determine the longevity and quality of Class I and Class II resin composite (Herculite XR) restorations placed in private practice.

METHODS

One thousand two hundred and nine Class I and Class II composite restorations with margins in enamel were evaluated clinically after periods of between 12 months and 4.5 years in clinical service by two calibrated examiners using a modified version of established criteria.

RESULTS

Of the restorations investigated 94.8% were rated as 'good' (Alpha 79.3%) or 'clinically acceptable' (Bravo 15.5%). Significantly more restorations in premolar teeth were rated as Alpha (82%) than in permanent molar teeth (77%). The survival rate after 4 years was around 87%. The 50% survival-time, calculated by extrapolation according to Weibull, was approximately 9 years.

CONCLUSIONS

It is concluded that the composite investigated is an appropriate material for the restoration of Class I and Class II lesions with margins located in enamel in premolar and permanent molar teeth.