The present invention relates to systems and methods using optical or electrical spectroscopy for accurate detection and monitoring of biological tissue properties in a noninvasive manner. To perform in vivo diagnose with more accurate and repeatable measurements, an air-tight micro suction cup is placed against biological tissue under test (such as skin of a patient), around which an electrical or optical sensing system comprising excitation and detection sensors is integrated. Applying a high power suction pump over the micro cup, a negative pressure is generated to reshape the skin covered by the cup to a contour suitable for better measurement results. Most important, as the suction power increases, certain amount of blood flow or body fluid is brought to skin layer, providing great potential of improving those diagnoses that require direct analysis over these biological components.
