The goal of the project is the development of a lab-on-chip for recognition of human papillomavirus (HPV) by electrochemiluminescence (ECL) techniques and amorphous silicon sensors.
The lab-on-chip consists of an optoelectronic platform (System-on-Glass) coupled to a disposable microfluidic chip, containing the biological solutions to be analyzed, and connected to an electronic board which controls the timing and operations for biomolecular analysis, processing of data and result's visualization.
The System-on-Glass integrates the functional modules needed to carry out the required analysis for the HPV detection: one for the RNA/DNA amplification using thin-film heaters and thin film temperature sensors and one for on-chip ECL detection through amorphous silicon photosensors.
The microfluidic chip includes a process chamber where the RNA/DNA amplification occurs and a site, for capturing specific probes, which hosts also transparent electrodes for activating the ECL process.
Control electronics includes embedded electronic circuits based on microcontrollers for the read-out of photosensors and temperature sensor, the driving of the thin film heaters, the temperature sensors and the ECL electrodes.
The micro/opto-electronic devices in the lab-on-chip allow the achievement of important scientific objectives:
a) overcoming the current limits of lab-on-chip in terms of miniaturization and portability;
b) development of extremely innovative and sensitive systems for detection of HPV.
Both objectives are achieved thanks to the combination of thin film microelectronic devices integrated on glass substrates, high-efficiency ECL electrodes and specific biomolecular recognition procedures.
The project requires multidisciplinary skills, that are well-represented by project components, which guarantee the know-how and experience required to advance scientific knowledge in the fields of microelectronics and its integration with biology and chemistry.
The development of the proposed lab-on-chip represents a significant improvement in the performance of current LOCs from a scientific and technological point of view because it allows for an effective miniaturization and for the integration of both highly specific molecular recognition techniques and high-sensitivity detection techniques.
The proposed lab-on-chip goes beyond the state-of-the-art of the current LOCs because combines:
1. optical detection techniques that offer the best detection limits [1] in LOCs, and in particular "on-chip" detection techniques based on hydrogenated amorphous silicon photosensors (a-Si: H) that allow efficient miniaturization and analytical performance comparable to those of cooled CCD chambers (off-chip detection) [2,3];
2. ECL techniques, which are particularly suitable for the development of miniaturized and ultra-sensitized tests, as they provide simplicity, rapidity and high readability [4];
3. thermal processing techniques of biomolecules by thin film heaters and temperature sensors in a-Si: H suitable for the production of compact systems [5, 6];
4. microcontroller-based electronics that allow the development of low-power and compact system.
The portable diagnostic devices developed in the project will be able to independently and quickly analyze biological samples in non-specialized environments (eg medical outpatient clinics or medical attendance in developing countries) with high reliability.
The points of most scientific innovation are:
a) the identification of high efficiency, transparent electrodes, deposited on glass substrates, that can induce ECL;
b) integration of such electrodes into a low-cost microfluidic system in which the biomolecular recognition of the virus takes place;
c) integration of the driving electronics of the ECL electrode into the already-developed control electronics;
d) identification of bioanalytical procedures for the biomolecular recognition of the virus;
e) accurate design of the system to overcome the issues of biocompatibility between microelectronic devices and biological solutions.
The success of the project will create the know-how necessary for the implementation of integrated chemical and biomolecular analysis systems for the identification of other viruses or biomarkers of pathology and more generally for in situ chemical analysis of different classes of compounds. In fact, by modifying the molecular recognition elements (gene probes, primers) and spatial arrangement of elements on the SoG, the proposed LOC can easily be adapted to the determination of other analytes to significantly improve the effectiveness of the diagnosis and follow-up of many other human pathologies and also find application in other areas of bioanalytical chemistry such as food, veterinarian and forensic analysis.
The final device is also a low-cost system because each individual analysis will have a reduced price due to the LOC characteristics where the amount of reagents and solutions used is minimal (few microliters). This will result in a total reduction in health costs, both from the point of view of the instrumentation and the management of the disease. These characteristics make highly desirable to implement and disseminate the system.
Lastly, the development of the system-on-glass, microfluidic chip, bioanalytical procedures, control and reading electronics and the entire system will be expected to be published in international journals with a high impact factor.
References
[1] E. Ghafar-Zadeh et al., Analog Integr Circ Sig Process, vol. 59 (1), pp 1-12, 2009
[2] M. Mirasoli et al., Analytical and Bioanalytical Chemistry, vol. 406 (23), pp 5645-5656, 2014
[3] A.T. Pereira et al., Biomicrofluidics, vol. 5 (1), 014102, 2011
[4] K. Kadimisetty et al., Anal Chem., 2015; vol. 87 (8), pp. 4472-4478, 2015
[5] A. Scorzoni et al., Sensors and Actuators A: Physical, vol. 229, 2015