Degree: Doctor

Affiliation(s):

Bio

As a materials scientist, I have made impactful contributions to the fields of electrocatalysis, electrochemical biosensors, green chemistry, and renewable energy. My academic journey began with a BSc in Chemistry from the University of Alicante (UA) and progressed with a PhD in Chemistry from The University of Porto (UPORTO) in 2009, where I delved into the fascinating properties of self-assembled monolayers of alkanethiols on gold electrodes.

In 2009, I embarked on an exciting venture at the Instituto Universitario de Electroquímica (UA), pioneering the preparation and characterization of cutting-edge all-solid-state photovoltaic cells. Using semiconductor quantum dots as light harvesters and conducting polymers as hole-transporting materials, I contributed to pushing the boundaries of solar energy technology. Since 2011, my career has flourished at the Centro de Investigação em Química da Universidade do Porto (CIQUP), part of the esteemed Associated Laboratory Institute of Molecular Sciences (IMS).

Throughout this incredible journey, my work has been primarily directed towards enhancing the performance of electrochemical biosensors by developing hybrid nanomaterials combining natural biopolymers, carbon nanostructures, biomolecules (such as proteins and fragments), and entire biological species (e.g., bacteriophages). At the same time, I spearheaded the first demonstration of electropolymerizing highly conductive polyaniline (PANI) films from deep eutectic solvents (DES), a pioneering study that is getting increasing attention. I have also made significant contributions to green chemistry for a sustainable future. To this end, we performed studies to develop ultrasonic methods for fabricating biocompatible nanoparticles with size control, showcasing the potential of environmentally friendly techniques. The preparation of composites using these nanoparticles has shown great potential for fine-tunning the physical properties of bioplastics. 

 

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Publications
Showing 5 latest publications. Total publications: 22
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1. A layered nanocomposite of laccase, chitosan, and Fe3O4 nanoparticles-reduced graphene oxide for the nanomolar electrochemical detection of bisphenol A, Fernandes, PMV; Campina, JM Silva, AF in MICROCHIMICA ACTA, 2020, ISSN: 0026-3672,  Volume: 187, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.1007/s00604-020-4223-x P-00S-0A3
Abstract A hybrid conjugate of reduced graphene oxide/ferrous-ferric oxide nanoparticles (rGO-Fe3O4 NPs) is characterized and assembled with chitosan and laccase to form a layered functional superstructure. After its characterization by field-effect scanning electron microscopy, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, attenuated total reflectance Fourier transform infrared, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), the nanocomposite has been deposited on glassy carbon for the enzyme-mediated electrochemical determination of the endocrine disruptor bisphenol A (BPA). Proof-of-concept assays conducted by using CV, EIS, and square wave voltammetry reveal that the enzymatic biosensor provides linear response in a wide range of BPA concentrations (6-228 ppb), very high sensitivities, and excellent durability (over 1-month storage). Using amperometric detection, remarkable sensitivities (2080 mu A mu M-1 cm(-2)) and detection limits (18 nM) are attained. Applications to real samples of bottled water proved feasible with recoveries in the range 107-124%.
2. Edible Chitosan Films and Their Nanosized Counterparts Exhibit Antimicrobial Activity and Enhanced Mechanical and Barrier Properties, Gomes, LP; Souza, HKS; Campina, JM Andrade, CT; Silva, AF Goncalves, MP; Flosi Paschoalin, VMF in MOLECULES, 2019, ISSN: 1420-3049,  Volume: 24, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.3390/molecules24010127 P-00Q-3BX
Abstract Chitosan and chitosan-nanoparticles were combined to prepare biobased and unplasticized film blends displaying antimicrobial activity. Nanosized chitosans obtained by sonication for 5, 15, or 30 min were combined with chitosan at 3:7, 1:1, and 7:3 ratios, in order to adjust blend film mechanical properties and permeability. The incorporation of nanosized chitosans led to improvements in the interfacial interaction with chitosan microfibers, positively affecting film mechanical strength and stiffness, evidenced by scanning electron microscopy. Nanosized or blend chitosan film sensitivity to moisture was significantly decreased with the drop in biocomposite molecular masses, evidenced by increased water solubility and decreased water vapor permeability. Nanosized and chitosan interactions gave rise to light biobased films presenting discrete opacity and color changes, since red-green and yellow-blue colorations were affected. All chitosan blend films exhibited antimicrobial activity against both Gram-positive and Gram-negative bacteria. The performance of green unplasticized chitosan blend films displaying diverse morphologies has, thus, been proven as a potential step towards the design of nontoxic food packaging biobased films, protecting against spoilage microorganisms, while also minimizing environmental impacts.
3. Reduced graphene oxide-nickel nanoparticles/biopolymer composite films for the sub-millimolar detection of glucose, Krishna, R; Campina, JM Fernandes, PMV; Ventura, J; Titus, E; Silva, AF in ANALYST, 2016, ISSN: 0003-2654,  Volume: 141, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.1039/c6an00475j P-00K-KQ3
Abstract Hybrid conjugates of graphene with metallic/semiconducting nanostructures can improve the sensitivity of electrochemical sensors due to their combination of well-balanced electrical/electrocatalytic properties and superior surface-to-volume ratio. In this study, the synthesis and physical characterization of a hybrid conjugate of reduced graphene oxide and nickel nanoparticles (rGO-Ni NPs) is presented. The conjugate was further deposited onto a glassy carbon electrode as a nanocomposite film of chitosan and glucose oxidase. The electrochemical response and morphology of the films were investigated using SEM, CV, and EIS, and their applications as a glucose biosensor explored for the first time in proof-of-concept tests. The low operating potential along with the good linearity and sensitivity (up to 129 mu A cm(-2) mM(-1)) found in the sub-millimolar range suggest potential applications in the self-management of hypoglycemia from blood samples or in the development of non-invasive assays for body fluids such as saliva, tears or breath.
4. Tweaking the mechanical and structural properties of colloidal chitosans by sonication, Gomes, LP; Souza, HKS; Campina, JM Andrade, CT; Flosi Paschoalin, VMF; Silva, AF Goncalves, MP in FOOD HYDROCOLLOIDS, 2016, ISSN: 0268-005X,  Volume: 56, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.1016/j.foodhyd.2015.11.021 P-00K-3BV
Abstract Compared to the oil-derived plastics typically used in food packaging, biofilms of pure chitosan present serious moisture issues. The physical degradation of the polysaccharide with ultrasound effectively reduces the water vapor permeability in these films but, unfortunately, they also turn more brittle. Blending chitosans of different morphology and molecular mass (M) is an unexplored strategy that could bring balance without the need of incorporating toxic or non-biodegradable plasticizers. To this end, we prepared and characterized the mixtures of a high-M chitosan with the products of its own ultrasonic fragmentation. Biopolymer degradation was followed by dynamic light scattering (DLS) and the mechanical and structural characteristics of the mixtures were evaluated from different rheological methods and atomic force microscopy (AFM). The results indicate that, through the control of the sonication time and mixture ratio, it is possible to adjust the viscoelasticity and morphological aspect of the mixtures at intermediate levels relative to their individual components. In a more general sense, it is emphasized the importance of design and materials processing for the development of a novel generation of additive-free sustainable but functional bioplastics.
5. Ultrasound-assisted preparation of size-controlled chitosan nanoparticles: Characterization and fabrication of transparent biofilms, Souza, HKS; Campina, JM Sousa, AMM; Silva, F Goncalves, MP in FOOD HYDROCOLLOIDS, 2013, ISSN: 0268-005X,  Volume: 31, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.1016/j.foodhyd.2012.10.005 P-001-ZTT
Abstract The use of biodegradable natural polymers is a suitable alternative for the preparation of more environmentally-friendly plastics and biocompatible nanoparticulated systems. Chitosan is an abundant and inexpensive candidate. However, its transparent films present poor mechanical response and high sensitivity to moisture. Moreover, the findings made by different researchers on the effects of molecular mass and degree of deacetylation (DD) on these properties are still controversial. This paper aims to unveil the separate effects of these parameters on biofilm properties. For these purposes, two aqueous solutions of chitosan (DD = 90 and 95%) were submitted to controlled fragmentation by ultrasonication. The resulting solutions were characterized by rheological techniques and the nanoparticles formed were studied ex-situ by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Irrespective of DD, the application of longer sonication times reduced the viscoelasticity of the solutions and yielded nanoparticles with lower size (and molecular mass). The mechanical strength and stiffness of transparent biofilms fabricated from these solutions, without plasticizers, were determined in stress tests. Sensitivity to moisture was also evaluated through water vapor permeability measurements and water sorption isothermal data. The results showed a significant decrease in the permeability with decreasing the molecular mass. However, the mechanical properties were adversely affected. These findings may be useful for the future design of bioplastics with improved properties but also for the development of biocompatible nanoparticles with tunable size and molecular mass.