Pedro Estrela | University of Bath (original) (raw)

Papers by Pedro Estrela

Social Science Research Network, 2022

Biomaterials advances, Aug 1, 2023

During the recent pandemic outbreak, Lab-on-Chip devices did not manage to fully reach their pote... more During the recent pandemic outbreak, Lab-on-Chip devices did not manage to fully reach their potential in rapid diagnosis of pathogens, mainly due to the lack of cost-effective LoC solutions integrated with all required sample preparation modules. This paper presents such a critical step, aiming to translate electrochemical pH control into practical protein preconcentration modules, easy to integrate with subsequent quantification modules seamlessly via Labon-PCB technology. In this work we present a device capable of electrochemically controlling the pH of a solution local to an individually addressed electrode in a PCB array. The electrodes were functionalised with an electropolymerised self-assembled monolayer of 4-Aminothiophenol and were subjected to voltages of 0.2-0.4 V, evaluating for the first time the bias effect both over time and over space. This study enables for the first time the implementation of this technique for electrochemical pH control into practical Lab-on-PCB devices such as isoelectric focusing, via the informed design of such electrode arrays of appropriate size and spacing.

Journal of Colloid and Interface Science, Oct 1, 2019

The fascinating properties of graphene can be augmented with other nanomaterials to generate hybr... more The fascinating properties of graphene can be augmented with other nanomaterials to generate hybrids to design innovative applications. Contrary to the conventional methodologies, we showed a novel yet simple, in-situ, biological approach which allowed for the effective growth of gold nanostructures on graphene surfaces (3D Au NS@GO). The morphology of the obtained hybrid consisted of sheets of graphene, anchoring uniform dispersion of ultra-small gold nanostructures of about 2-8 nm diameter. Surface plasmon resonance at 380 nm confirmed the nano-regimen of the hybrid. Fourier transform infrared spectroscopy indicated the utilization of amine spacers to host gold ions leading to nucleation and growth. The exceptional positive surface potential of 55 mV suggest that the hybrid as an ideal support for electrocatalysis. Ultimately, the hybrid was found to be an efficient receptor material for electrochemical performance towards the binding of uric acid which is an important biomolecule of human metabolism. The designed material enabled the detection of uric acid concentrations as low as 30 nM. This synthesis strategy is highly suitable to design new hybrid materials with interesting morphology and outstanding properties for the identification of clinically relevant biomolecules.

Sensors, Jul 20, 2023

The clinical manifestation of leptospirosis is often misdiagnosed as other febrile illnesses such... more The clinical manifestation of leptospirosis is often misdiagnosed as other febrile illnesses such as dengue. Therefore, there is an urgent need for a precise diagnostic tool at the field level to detect the pathogenic Leptospira lipL32 gene at the molecular level for prompt therapeutic decisions. Quantitative polymerase chain reaction (qPCR) is widely used as the primary diagnostic tool, but its applicability is limited by high equipment cost and the lack of availability in every hospital, especially in rural areas where leptospirosis mainly occurs. Here, we report the development of a CRISPR dFnCas9-based quantitative lateral flow immunoassay to detect the lipL32 gene. The developed assay showed superior performance regarding the lowest detectable limit of 1 fg/mL. The test is highly sensitive and selective, showing that leptospirosis diagnosis can be achieved with a low-cost lateral flow device.

Research Square (Research Square), Jul 13, 2023

Protein preconcentration is an essential sample preparation step when analysing samples where the... more Protein preconcentration is an essential sample preparation step when analysing samples where the targeted proteins are in low concentrations, such as bodily uids as well as water or wastewater. Nonetheless, very few practical implementations of miniaturized protein pre-concentration devices have been demonstrated in practice and even fewer in integration with other microanalytical steps. In this paper we propose for the rst time a miniaturized isoelectric focusing-based protein-preconcentration device based on electrochemically derived pH gradients, rather than existing chemical reagent approaches. That way we are reducing the need for additional chemical reagents to zero, whilst enabling the device incorporation in a seamlessly integrated full protein analysis microsystem via Lab-on-PCB technology. We apply our previously presented Lab-on-PCB approach to quantitatively control the pH of a solution at the vicinity of planar electrodes using the electrochemical generation of acid through redox-active self-assembled monolayers. The presented device was comprised of a printed circuit board with an array of gold electrodes which was functionalised with 4-Aminothiophenol; this formed a self-assembled monolayer which was electropolymerised to improve its electrochemical reversibility. Protein preconcentration was performed in two con gurations, one of which was open and required the use of a holder to suspend a well of uid above the electrodes, and another which used micro uidic channels to enclose small volumes of uid. Reported here is the data for protein preconcentration in both these forms with a quantitative concentration factor shown for the open form and qualitative proof shown for the micro uidic.

Springer eBooks, 2015

Biotechnology is in great need of low-cost intelligent biochips capable of massive parallel detec... more Biotechnology is in great need of low-cost intelligent biochips capable of massive parallel detection to be used in portable instrumentation. One way this may be achieved is to exploit mature semiconductor technologies for the development of biosensor arrays. Potentiometric chemical and biological sensors detect electric potential variations which arise at the surface of a solid material when placed in contact with an electrolyte. BioFETs are semiconductor structures functionalized with suitable bioreceptors, which detect biomolecular interactions in a label-free potentiometric fashion and with great sensitivity. They can be easily integrated into low-cost arrays of sensors with portable instrumentation for the parallel screening of large panels of analytes.