An Infrared Absorbance Sensor for the Detection of Melanoma in Skin Biopsies.

An infrared (IR) absorbance sensor has been designed, realized and tested with the aim of detecting malignant melanomas in human skin biopsies. The sensor has been designed to obtain fast measurements (80 s) of a biopsy using a small light spot (0.5 mm in diameter, typically five to 10 times smaller than the biopsy size) to investigate different biopsy areas. The sensor has been equipped with a monochromator to record the whole IR spectrum in the 3330-3570 nm wavelength range (where methylene and methyl stretching vibrations occur) for a qualitative spectral investigation. From the collected spectra, the CH2 stretch ratio values (ratio of the absorption intensities of the symmetric to asymmetric CH2 stretching peaks) are determined and studied as a cancer indicator. Melanoma areas exhibit different spectral shapes and significantly higher CH2 stretch ratios when compared to healthy skin. The results of the infrared investigation are compared with standard histology. This study shows that the IR sensor is a promising supportive tool to improve the diagnosis of melanoma during histopathological analysis, decreasing the risk of misdiagnosis.

A compact and integrated immunoassay with on-chip dispensing and magnetic particle handling.

We present a compact diagnostic platform for a rapid and sensitive detection of plasma biomarkers. The platform consists of a disposable microfluidic polymer chip, a processing device including a lens-free and cost efficient sensor system and a setup for dispersion of magnetic particles. The biomarkers of interest are quantified by magnetic bead based immunoassays with chemiluminescent readout technology. With a novel system for dispersion and manipulation of the magnetic particles in combination with chemiluminescence detection, the sensitivity of the immunoassay is improved and enables a rapid assay in a microfluidic format. In the disposable chip, extra chambers for storage and dispensing of biomarker specific reagents are integrated, which reduce the need of external dosing devices and thereby the cost of the platform is decreased. Plasma biomarkers for monitoring of sepsis could be quantified at 10 pg/mL concentrations within a total time of 30 min by the present system. This contribution is a fundamental step towards the development of an automatic and compact Point-of-Care testing device for monitoring of patients at the intensive care unit.