Resumen de Towards label-free biosensing in compact disk technologies f or point-of-need analysis
This thesis explores new analytical advances using compact disk biosensing technologies, and comprises six scientific publications distributed along four chapters. Special attention is herein payed to Thermochromic Etching Disks (TED) technology (Chapter 1), rational design of disk-based biorecognition assays (Chapter 2), and label-free detection systems for point-of-need analysis (Chapters 3 and 4).
First, insights into a novel light-mediated signal developing system for biorecognition assays (based on TED disks and drives) are provided together with an overview of the state-of-the art and future trends in photo- and thermochromic biosensing. This signal developing approach exploits photo- and thermochromism for biosensing in an original manner and represents a potential strategy to simplify signaling processes in bioanalytical systems. Then, how to transform TED technology into lab-on-a-disk systems is addressed. TED has proven to be a very versatile tool to perform sensitive analysis of biorecognition assays, using platforms and scanners easily obtained from regular disks and drives, respectively. Biologically relevant assays of different nature (microarray, cell culture, immunofiltration, turbidimetry, etc.) have been arrayed in a single disk and sensitively analyzed by imaging.
Regarding rational design, a theoretical-experimental method (INSEL) based on kinetics and mass-transport modelling for optimizing biorecognition assays and exploring their behavior is presented. INSEL has been implemented as an in silico tool that enables to characterize biointeractions with minimal experimentation, to perform optimizations directed towards custom objectives defined by the user, and to easily compute the effect of critical variables without further experiments.
In another study included in this thesis, polycarbonate grooved structures obtained from standard recordable disks (CD-R and DVD-R) were coated with silver and tailored to become SERS-active. This strategy represents a cost-effective and industrially scalable alternative to the SERS substrates typically used for bioanalysis. These disk-based materials have presented tunable plasmonic responses, significant Raman enhancement, and have allowed complex biological targets (such as proteins and exosomes) to be analyzed by SERS without using labeled reagents as tracers. In addition to introduce inexpensive and large-scale SERS substrates for biosensing, this study also suggests the development of prospective Raman scanners based on disk drives.
Another approach herein presented addresses the implementation of diffraction-based sensing (DBS) in TED technology in order to conceive disk-based label-free biosensors based on standard disks and drives. At first, a comprehensive experimental assessment of the analytical possibilities offered by DBS is presented. Then, the fabrication of arrays of diffractive protein networks on TED disks is investigated, with which sensitive analysis of antibodies in label-free conditions has been demonstrated, using adapted drives as scanners. This investigation provides important insights into cost-effective and industrially scalable functional materials and detection setups that exploit consumer electronics for label-free biosensing.
