Porous Silicon as Transducer for Immune Sensors: From Theory to Practice

Abstract

Porous silicon (PS) attracts more and more attention of the investigators. It has already found its application not only in optoelectronic elements, such as light-emitting diodes, photodetectors, etc., but also in biochips, which can be implanted into human organism, and biological sensors capable of measuring a number of substances. PS has recently been shown to possess visible photoluminescence (PhL) and electroluminescence. The nature of the PhL is still under discussion but quantum-dimensional theory seems to prevail as a possible explanation of the PhL mechanism. In this work a new application of PS, namely its promising use for the creation of immune sensors, is discussed. Laboratory prototypes of immune sensors based on the PS PhL were developed for the registration of myoglobin in blood serum and biological components in the air that can cause allergic reaction in people. The results obtained with the help of the sensor approach were compared with the data of the ELISA method. The difference between them was not statistically significant but sensor analysis was much shorter, simpler and cheaper than the ELISA method. The concentration of biological compounds in the air was determined also with an immune sensor based on the optical fibres in combination with enhanced chemical luminescence. The immune sensor based on the PS PhL showed sensitivity nearly to the optical fibre sensor but it was simpler in the construction and operation. Moreover, it allowed direct registration (without need of any label) of specific interactions between immune components. The obtained results show that PS and especially its ability to emit visible PhL can be successfully used for the development of new types of biological sensors. The elaborated models of the immune sensors on the basis of PS PhL are promising for their further improvement and production of principally new instrumental devices for the monitoring of the air contamination by biological components of different nature and diagnostics of the state of the human organism. Moreover, achievements of this study intrigue and stimulate further investigations on the use of the PS for enzyme-, DNA- or other types of biological sensors.