@article{Hasimoto2024,

title = {Strain and defect-engineering on the basal plane of ultra-large MoS2 monolayers attached onto stretchable gold electrodes},

author = {Leonardo H. Hasimoto and Ana B. S. de Araujo and Cláudia de Lourenço and Leandro Merces and Graziâni Candioto and Edson R. Leite and Rodrigo B. Capaz and Murilo Santhiago},

url = {https://pubs.rsc.org/en/content/articlehtml/2024/ta/d4ta02042a},

doi = {10.1039/d4ta02042a},

issn = {2050-7496},

year  = {2024},

date = {2024-07-16},

urldate = {2024-07-16},

journal = {J. Mater. Chem. A},

volume = {12},

number = {28},

pages = {17338--17349},

publisher = {Royal Society of Chemistry (RSC)},

abstract = {Strain and defect-engineering methods have been widely used to tune a variety of properties of monolayer MoS2 towards optical, electronic, mechanical, and electrochemical applications. For electrochemical applications in the field of energy, i.e. hydrogen evolution reaction (HER), defects act as catalytic sites to promote this reaction. Thus, the creation of routes that convert the relatively inert MoS2 basal plane into an HER-active system plays an essential role in this field. In this work, we report an innovative method that can generate both strain and edge-like defects on ultra-large MoS2 monolayers anchored onto stretchable gold electrodes. By simply stretching the electrodes, tensile strain, and oriented crack formation were achieved on the basal plane. Raman, photoluminescence, and atomic force microscopy experiments confirmed the presence of strain. Simulation of the stretching process reveals the regions that are more prone to crack, which was experimentally confirmed by scanning electron microscopy and laser scanning confocal microscopy measurements. Density functional theory studies confirm that curvature effects alone do not improve significantly the HER activity, thus emphasizing the need to produce cracks in the MoS2 monolayers to improve the catalytic activity. Finally, the stretch-induced cracks can reduce the overpotential measured at 10 mA cm−2 to 352 mV. The electrocatalytic activity is superior when compared to pristine MoS2 and presents remarkable stability up to 500 cycles.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Rocha2023b,

title = {Tuning the Chemical and Electrochemical Properties of Paper-Based Carbon Electrodes by Pyrolysis of Polydopamine},

author = {Jaqueline F. Rocha and Julia C. de Oliveira and Jefferson Bettini and Mathias Strauss and Guilherme S. Selmi and Anderson K. Okazaki and Rafael F. de Oliveira and Renato S. Lima and Murilo Santhiago},

url = {https://pubs.acs.org/doi/full/10.1021/acsmeasuresciau.3c00063},

doi = {10.1021/acsmeasuresciau.3c00063},

issn = {2694-250X},

year  = {2024},

date = {2024-04-17},

urldate = {2024-04-17},

journal = {ACS Meas. Sci. Au},

volume = {4},

number = {2},

pages = {188--200},

publisher = {American Chemical Society (ACS)},

abstract = {Electrochemical paper-based analytical devices represent an important platform for portable, low-cost, affordable, and decentralized diagnostics. For this kind of application, chemical functionalization plays a pivotal role to ensure high clinical performance by tuning surface properties and the area of electrodes. However, controlling different surface properties of electrodes by using a single functionalization route is still challenging. In this work, we attempted to tune the wettability, chemical composition, and electroactive area of carbon-paper-based devices by thermally treating polydopamine (PDA) at different temperatures. PDA films were deposited onto pyrolyzed paper (PP) electrodes and thermally treated in the range of 300–1000 °C. After deposition of PDA, the surface is rich in nitrogen and oxygen, it is superhydrophilic, and it has a high electroactive area. As the temperature increases, the surface becomes hydrophobic, and the electroactive area decreases. The surface modifications were followed by Raman, X-ray photoelectron microscopy (XPS), laser scanning confocal microscopy (LSCM), contact angle, scanning electron microscopy (SEM-EDS), electrical measurements, transmission electron microscopy (TEM), and electrochemical experiments. In addition, the chemical composition of nitrogen species can be tuned on the surface. As a proof of concept, we employed PDA-treated surfaces to anchor [AuCl4]− ions. After electrochemical reduction, we observed that it is possible to control the size of the nanoparticles on the surface. Our route opens a new avenue to add versatility to electrochemical interfaces in the field of paper-based electrochemical biosensors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Costa2024,

title = {Single‐Response Duplexing of Electrochemical Label‐Free Biosensor from the Same Tag},

author = {Juliana N. Y. Costa and Gabriel J. C. Pimentel and Júlia A. Poker and Leandro Merces and Waldemir J. Paschoalino and Luis C. S. Vieira and Ana C. H. Castro and Wendel A. Alves and Lucas B. Ayres and Lauro T. Kubota and Murilo Santhiago and Carlos D. Garcia and Maria H. O. Piazzetta and Angelo L. Gobbi and Flávio M. Shimizu and Renato S. Lima},

url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adhm.202303509},

doi = {10.1002/adhm.202303509},

issn = {2192-2659},

year  = {2024},

date = {2024-04-00},

urldate = {2024-04-00},

journal = {Adv Healthcare Materials},

volume = {13},

number = {11},

publisher = {Wiley},

abstract = {Multiplexing is a valuable strategy to boost throughput and improve clinical accuracy. Exploiting the vertical, meshed design of reproducible and low-cost ultra-dense electrochemical chips, the unprecedented single-response multiplexing of typical label-free biosensors is reported. Using a cheap, handheld one-channel workstation and a single redox probe, that is, ferro/ferricyanide, the recognition events taking place on two spatially resolved locations of the same working electrode can be tracked along a single voltammetry scan by collecting the electrochemical signatures of the probe in relation to different quasi-reference electrodes, Au (0 V) and Ag/AgCl ink (+0.2 V). This spatial isolation prevents crosstalk between the redox tags and interferences over functionalization and binding steps, representing an advantage over the existing non-spatially resolved single-response multiplex strategies. As proof of concept, peptide-tethered immunosensors are demonstrated to provide the duplex detection of COVID-19 antibodies, thereby doubling the throughput while achieving 100% accuracy in serum samples. The approach is envisioned to enable broad applications in high-throughput and multi-analyte platforms, as it can be tailored to other biosensing devices and formats.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Costa2024b,

title = {Single‐Response Duplexing of Electrochemical Label‐Free Biosensor from the Same Tag},

author = {Juliana N. Y. Costa and Gabriel J. C. Pimentel and Júlia A. Poker and Leandro Merces and Waldemir J. Paschoalino and Luis C. S. Vieira and Ana C. H. Castro and Wendel A. Alves and Lucas B. Ayres and Lauro T. Kubota and Murilo Santhiago and Carlos D. Garcia and Maria H. O. Piazzetta and Angelo L. Gobbi and Flávio M. Shimizu and Renato S. Lima},

url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adhm.202303509},

doi = {10.1002/adhm.202303509},

issn = {2192-2659},

year  = {2024},

date = {2024-04-00},

urldate = {2024-04-00},

journal = {Adv Healthcare Materials},

volume = {13},

number = {11},

publisher = {Wiley},

abstract = {Multiplexing is a valuable strategy to boost throughput and improve clinical accuracy. Exploiting the vertical, meshed design of reproducible and low-cost ultra-dense electrochemical chips, the unprecedented single-response multiplexing of typical label-free biosensors is reported. Using a cheap, handheld one-channel workstation and a single redox probe, that is, ferro/ferricyanide, the recognition events taking place on two spatially resolved locations of the same working electrode can be tracked along a single voltammetry scan by collecting the electrochemical signatures of the probe in relation to different quasi-reference electrodes, Au (0 V) and Ag/AgCl ink (+0.2 V). This spatial isolation prevents crosstalk between the redox tags and interferences over functionalization and binding steps, representing an advantage over the existing non-spatially resolved single-response multiplex strategies. As proof of concept, peptide-tethered immunosensors are demonstrated to provide the duplex detection of COVID-19 antibodies, thereby doubling the throughput while achieving 100% accuracy in serum samples. The approach is envisioned to enable broad applications in high-throughput and multi-analyte platforms, as it can be tailored to other biosensing devices and formats.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Florindo2023b,

title = {Patterning edge-like defects and tuning defective areas on the basal plane of ultra-large MoS_{2} monolayers toward the hydrogen evolution reaction},

author = {Bianca Rocha Florindo and Leonardo H. Hasimoto and Nicolli de Freitas and Graziâni Candiotto and Erika Nascimento Lima and Cláudia de Lourenço and Ana B. S. de Araujo and Carlos Ospina and Jefferson Bettini and Edson R. Leite and Renato S. Lima and Adalberto Fazzio and Rodrigo B. Capaz and Murilo Santhiago},

url = {https://pubs.rsc.org/en/content/articlelanding/2012/pk/d3ta04225a/unauth},

doi = {10.1039/d3ta04225a},

issn = {2050-7496},

year  = {2023},

date = {2023-09-26},

urldate = {2023-09-26},

journal = {J. Mater. Chem. A},

volume = {11},

number = {37},

pages = {19890--19899},

publisher = {Royal Society of Chemistry (RSC)},

abstract = {The catalytic sites of MoS2 monolayers towards hydrogen evolution are well known to be vacancies and edge-like defects. However, it is still very challenging to control the position, size, and defective areas on the basal plane of MoS2 monolayers by most of the defect-engineering routes. In this work, the fabrication of etched arrays on ultra-large supported and free-standing MoS2 monolayers using a focused ion beam (FIB) is reported for the first time. By tuning the Ga+ ion dose, it is possible to confine defects near the etched edges or spread them over ultra-large areas on the basal plane. The electrocatalytic activity of the arrays toward the hydrogen evolution reaction (HER) was measured by fabricating microelectrodes using a new method that preserves the catalytic sites. We demonstrate that the overpotential can be decreased up to 290 mV by assessing electrochemical activity only at the basal plane. High-resolution transmission electron microscopy images obtained on FIB patterned freestanding MoS2 monolayers reveal the presence of amorphous regions and X-ray photoelectron spectroscopy indicates sulfur excess in these regions. Density-functional theory calculations enable identification of catalytic defect sites. Our results demonstrate a new rational control of amorphous-crystalline surface boundaries and future insight for defect optimization in MoS2 monolayers.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Rocha2023,

title = {Recent progress and future perspectives of polydopamine nanofilms toward functional electrochemical sensors},

author = {Jaqueline F. Rocha and Leonardo H. Hasimoto and Murilo Santhiago},

url = {https://link.springer.com/article/10.1007/s00216-023-04522-z},

doi = {10.1007/s00216-023-04522-z},

issn = {1618-2650},

year  = {2023},

date = {2023-07-00},

urldate = {2023-07-00},

journal = {Anal Bioanal Chem},

volume = {415},

number = {18},

pages = {3799--3816},

publisher = {Springer Science and Business Media LLC},

abstract = {Since its discovery in 2007, polydopamine nanofilms have been widely used in many areas for surface functionalization. The simple and low-cost preparation method of the nanofilms with tunable thickness can incorporate amine and oxygen-rich chemical groups in virtually any interface. The remarkable advantages of this route have been successfully used in the field of electrochemical sensors. The self-adhesive properties of polydopamine are used to attach nanomaterials onto the electrode’s surface and add chemical groups that can be explored to immobilize recognizing species for the development of biosensors. Thus, the combination of 2D materials, nanoparticles, and other materials with polydopamine has been successfully demonstrated to improve the selectivity and sensitivity of electrochemical sensors. In this review, we highlight some interesting properties of polydopamine and some applications where polydopamine plays an important role in the field of electrochemical sensors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{deLimaTinoco2023,

title = {Scalable and green formation of graphitic nanolayers produces highly conductive pyrolyzed paper toward sensitive electrochemical sensors},

author = {Marcos V. de Lima Tinoco and Lucas R. Fujii and Caroline Y. N. Nicoliche and Gabriela F. Giordano and Julia A. Barbosa and Jaqueline F. da Rocha and Gabriel T. dos Santos and Jefferson Bettini and Murilo Santhiago and Mathias Strauss and Renato S. Lima},

url = {https://pubs.rsc.org/en/content/articlelanding/2023/nr/d2nr07080d/unauth},

doi = {10.1039/d2nr07080d},

issn = {2040-3372},

year  = {2023},

date = {2023-03-30},

urldate = {2023-03-30},

journal = {Nanoscale},

volume = {15},

number = {13},

pages = {6201--6214},

publisher = {Royal Society of Chemistry (RSC)},

abstract = {While pyrolyzed paper (PP) is a green and abundant material that can provide functionalized electrodes with wide detection windows for a plethora of targets, it poses long-standing challenges against sensing assays such as poor electrical conductivity, with resistivities generally higher than 200.0 mΩ cm (e.g., gold and silver show resistivities 1000-fold lower, ∼0.2 mΩ cm). In this regard, the fundamental hypothesis that drives this work is whether a scalable, cost-effective, and eco-friendly strategy is capable of significantly reducing the resistivity of PP electrodes toward the development of sensitive electrochemical sensors, whether faradaic or capacitive. We address this hypothesis by simply annealing PP under an isopropanol atmosphere for 1 h, reaching resistivities as low as 7 mΩ cm. Specifically, the annealing of PP at 800 or 1000 °C under isopropanol vapor leads to the formation of a highly graphitic nanolayer (∼15 nm) on the PP surface, boosting conductivity as the delocalization of π electrons stemming from carbon sp2 is favored. The reduction of carbonyl groups and the deposition of dehydrated isopropanol during the annealing process are hypothesized herein as the dominant PP graphitization mechanisms. Electrochemical analyses demonstrated the capability of the annealed PP to increase the charge-transfer kinetics, with the optimum heterogeneous standard rate constant being roughly 3.6 × 10−3 cm s−1. This value is larger than the constants reported for other carbon electrodes and indium tin oxide. Furthermore, freestanding fingers of the annealed PP were prototyped using a knife plotter to fabricate impedimetric on-leaf electrodes. These wearable sensors ensured the real-time and in situ monitoring of the loss of water content from soy leaves, outperforming non-annealed electrodes in terms of reproducibility and sensitivity. Such an application is of pivotal importance for precision agriculture and development of agricultural inputs. This work addresses the foundations for the achievement of conductive PP in a scalable, low-cost, simple, and eco-friendly way, i.e. without producing any liquid chemical waste, providing new opportunities to translate PP-based sensitive electrochemical devices into practical use.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hasimoto2022,

title = {Binary Cooperative Thermal Treatment of Cellulose and MoS_{2} for the Preparation of Sustainable Paper-Based Electrochemical Devices for Hydrogen Evolution},

author = {Leonardo H. Hasimoto and Jefferson Bettini and Edson R. Leite and Renato S. Lima and João Batista Souza Junior and Lifeng Liu and Murilo Santhiago},

url = {https://pubs.acs.org/doi/abs/10.1021/acsaenm.2c00087},

doi = {10.1021/acsaenm.2c00087},

issn = {2771-9545},

year  = {2023},

date = {2023-02-24},

urldate = {2023-02-24},

journal = {ACS Appl. Eng. Mater.},

volume = {1},

number = {2},

pages = {708--719},

publisher = {American Chemical Society (ACS)},

abstract = {The simple, fast, scalable, and integrative preparation of sustainable electrodes using earth-abundant materials toward energy applications is a long-standing challenge. In this work, we attempted to achieve such features by developing a binary cooperative thermal process using cellulose sheets and molybdenum disulfide (MoS2) toward hydrogen evolution reaction (HER). The thermal process converts cellulose into a highly conductive hydrophobic carbon-based material while generating chemical defects on MoS2. The latter is of fundamental importance to improve the catalytic activity for HER through activating the well-known inert MoS2 basal planes. Thermal desulfurization was confirmed by X-ray photoelectron spectroscopy, Kelvin probe force microscopy, Raman spectroscopy, and energy-dispersive X-ray spectroscopy. Interestingly, a desulfurization gradient was observed at the MoS2 particles, where the edges are more defective than the basal planes. The resulting defect-like MoS2 particles are highly active toward HER. In addition, the porosity of paper enables simple filtration of catalysts and the possibility to tune the electrochemically active surface area by simply adding isopropanol before the electrolysis. Finally, we showed an ultrafast coating method using a commercial MoS2 spray on sheets of paper that enables H2 bubble generation at specific regions of the electrode. The overpotential (η) positively shifted more than 300 mV when compared with nontreated MoS2, reaching η = 240 mV to obtain 10 mA cm–2 of HER current density.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Castro2022,

title = {Modular Label-Free Electrochemical Biosensor Loading Nature-Inspired Peptide toward the Widespread Use of COVID-19 Antibody Tests},

author = {Ana C. H. Castro and Ítalo R. S. Bezerra and Aline M. Pascon and Gabriela H. da Silva and Eric A. Philot and Vivian L. de Oliveira and Rodrigo S. N. Mancini and Gabriel R. Schleder and Carlos E. Castro and Luciani R. S. de Carvalho and Bianca H. V. Fernandes and Eduardo M. Cilli and Paulo R. S. Sanches and Murilo Santhiago and Ives Charlie-Silva and Diego S. T. Martinez and Ana L. Scott and Wendel A. Alves and Renato S. Lima},

url = {https://pubs.acs.org/doi/abs/10.1021/acsnano.2c04364},

doi = {10.1021/acsnano.2c04364},

issn = {1936-086X},

year  = {2022},

date = {2022-09-27},

urldate = {2022-09-27},

journal = {ACS Nano},

volume = {16},

number = {9},

pages = {14239--14253},

publisher = {American Chemical Society (ACS)},

abstract = {Limitations of the recognition elements in terms of synthesis, cost, availability, and stability have impaired the translation of biosensors into practical use. Inspired by nature to mimic the molecular recognition of the anti-SARS-CoV-2 S protein antibody (AbS) by the S protein binding site, we synthesized the peptide sequence of Asn-Asn-Ala-Thr-Asn-COOH (abbreviated as PEP2003) to create COVID-19 screening label-free (LF) biosensors based on a carbon electrode, gold nanoparticles (AuNPs), and electrochemical impedance spectroscopy. The PEP2003 is easily obtained by chemical synthesis, and it can be adsorbed on electrodes while maintaining its ability for AbS recognition, further leading to a sensitivity 3.4-fold higher than the full-length S protein, which is in agreement with the increase in the target-to-receptor size ratio. Peptide-loaded LF devices based on noncovalent immobilization were developed by affording fast and simple analyses, along with a modular functionalization. From studies by molecular docking, the peptide–AbS binding was found to be driven by hydrogen bonds and hydrophobic interactions. Moreover, the peptide is not amenable to denaturation, thus addressing the trade-off between scalability, cost, and robustness. The biosensor preserves 95.1% of the initial signal for 20 days when stored dry at 4 °C. With the aid of two simple equations fitted by machine learning (ML), the method was able to make the COVID-19 screening of 39 biological samples into healthy and infected groups with 100.0% accuracy. By taking advantage of peptide-related merits combined with advances in surface chemistry and ML-aided accuracy, this platform is promising to bring COVID-19 biosensors into mainstream use toward straightforward, fast, and accurate analyses at the point of care, with social and economic impacts being achieved.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Castro2022b,

title = {Modular Label-Free Electrochemical Biosensor Loading Nature-Inspired Peptide toward the Widespread Use of COVID-19 Antibody Tests},

author = {Ana C. H. Castro and Ítalo R. S. Bezerra and Aline M. Pascon and Gabriela H. da Silva and Eric A. Philot and Vivian L. de Oliveira and Rodrigo S. N. Mancini and Gabriel R. Schleder and Carlos E. Castro and Luciani R. S. de Carvalho and Bianca H. V. Fernandes and Eduardo M. Cilli and Paulo R. S. Sanches and Murilo Santhiago and Ives Charlie-Silva and Diego S. T. Martinez and Ana L. Scott and Wendel A. Alves and Renato S. Lima},

url = {https://pubs.acs.org/doi/abs/10.1021/acsnano.2c04364},

doi = {10.1021/acsnano.2c04364},

issn = {1936-086X},

year  = {2022},

date = {2022-09-27},

urldate = {2022-09-27},

journal = {ACS Nano},

volume = {16},

number = {9},

pages = {14239--14253},

publisher = {American Chemical Society (ACS)},

abstract = {Limitations of the recognition elements in terms of synthesis, cost, availability, and stability have impaired the translation of biosensors into practical use. Inspired by nature to mimic the molecular recognition of the anti-SARS-CoV-2 S protein antibody (AbS) by the S protein binding site, we synthesized the peptide sequence of Asn-Asn-Ala-Thr-Asn-COOH (abbreviated as PEP2003) to create COVID-19 screening label-free (LF) biosensors based on a carbon electrode, gold nanoparticles (AuNPs), and electrochemical impedance spectroscopy. The PEP2003 is easily obtained by chemical synthesis, and it can be adsorbed on electrodes while maintaining its ability for AbS recognition, further leading to a sensitivity 3.4-fold higher than the full-length S protein, which is in agreement with the increase in the target-to-receptor size ratio. Peptide-loaded LF devices based on noncovalent immobilization were developed by affording fast and simple analyses, along with a modular functionalization. From studies by molecular docking, the peptide–AbS binding was found to be driven by hydrogen bonds and hydrophobic interactions. Moreover, the peptide is not amenable to denaturation, thus addressing the trade-off between scalability, cost, and robustness. The biosensor preserves 95.1% of the initial signal for 20 days when stored dry at 4 °C. With the aid of two simple equations fitted by machine learning (ML), the method was able to make the COVID-19 screening of 39 biological samples into healthy and infected groups with 100.0% accuracy. By taking advantage of peptide-related merits combined with advances in surface chemistry and ML-aided accuracy, this platform is promising to bring COVID-19 biosensors into mainstream use toward straightforward, fast, and accurate analyses at the point of care, with social and economic impacts being achieved.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Barbosa2022b,

title = {Biocompatible Wearable Electrodes on Leaves toward the On-Site Monitoring of Water Loss from Plants},

author = {Júlia A. Barbosa and Vitoria M. S. Freitas and Lourenço H. B. Vidotto and Gabriel R. Schleder and Ricardo A. G. de Oliveira and Jaqueline F. da Rocha and Lauro T. Kubota and Luis C. S. Vieira and Hélio C. N. Tolentino and Itamar T. Neckel and Angelo L. Gobbi and Murilo Santhiago and Renato S. Lima},

url = {https://pubs.acs.org/doi/abs/10.1021/acsami.2c02943},

doi = {10.1021/acsami.2c02943},

issn = {1944-8252},

year  = {2022},

date = {2022-05-25},

urldate = {2022-05-25},

journal = {ACS Appl. Mater. Interfaces},

volume = {14},

number = {20},

pages = {22989--23001},

publisher = {American Chemical Society (ACS)},

abstract = {Impedimetric wearable sensors are a promising strategy for determining the loss of water content (LWC) from leaves because they can afford on-site and nondestructive quantification of cellular water from a single measurement. Because the water content is a key marker of leaf health, monitoring of the LWC can lend key insights into daily practice in precision agriculture, toxicity studies, and the development of agricultural inputs. Ongoing challenges with this monitoring are the on-leaf adhesion, compatibility, scalability, and reproducibility of the electrodes, especially when subjected to long-term measurements. This paper introduces a set of sensing material, technological, and data processing solutions that overwhelm such obstacles. Mass-production-suitable electrodes consisting of stand-alone Ni films obtained by well-established microfabrication methods or ecofriendly pyrolyzed paper enabled reproducible determination of the LWC from soy leaves with optimized sensibilities of 27.0 (Ni) and 17.5 kΩ %–1 (paper). The freestanding design of the Ni electrodes was further key to delivering high on-leaf adhesion and long-term compatibility. Their impedances remained unchanged under the action of wind at velocities of up to 2.00 m s–1, whereas X-ray nanoprobe fluorescence assays allowed us to confirm the Ni sensor compatibility by the monitoring of the soy leaf health in an electrode-exposed area. Both electrodes operated through direct transfer of the conductive materials on hairy soy leaves using an ordinary adhesive tape. We used a hand-held and low-power potentiostat with wireless connection to a smartphone to determine the LWC over 24 h. Impressively, a machine-learning model was able to convert the sensing responses into a simple mathematical equation that gauged the impairments on the water content at two temperatures (30 and 20 °C) with reduced root-mean-square errors (0.1% up to 0.3%). These data suggest broad applicability of the platform by enabling direct determination of the LWC from leaves even at variable temperatures. Overall, our findings may help to pave the way for translating “sense–act” technologies into practice toward the on-site and remote investigation of plant drought stress. These platforms can provide key information for aiding efficient data-driven management and guiding decision-making steps.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{deFreitas2022,

title = {Fast and efficient electrochemical thinning of ultra-large supported and free-standing MoS_{2} layers on gold surfaces},

author = {Nicolli de Freitas and Bianca R. Florindo and Vitória M. S. Freitas and Maria H. de O. Piazzetta and Carlos A. Ospina and Jefferson Bettini and Mathias Strauss and Edson R. Leite and Angelo L. Gobbi and Renato S. Lima and Murilo Santhiago},

url = {https://pubs.rsc.org/en/content/articlehtml/2022/nr/d2nr00491g},

doi = {10.1039/d2nr00491g},

issn = {2040-3372},

year  = {2022},

date = {2022-05-16},

urldate = {2022-05-16},

journal = {Nanoscale},

volume = {14},

number = {18},

pages = {6811--6821},

publisher = {Royal Society of Chemistry (RSC)},

abstract = {Molybdenum disulfide (MoS2) is a very promising layered material for electrical, optical, and electrochemical applications because of its unique and outstanding properties. To unlock its full potential, among different preparation routes, electrochemistry has gain interest due to its simple, fast, scalable and simple instrumentation. However, obtaining large-area monolayer MoS2 that will enable the fabrication of novel electronic and electrochemical devices is still challenging. In this work, we reported a simple and fast electrochemical thinning process that results in ultra-large MoS2 down to monolayer on Au surfaces. The high affinity of MoS2 by Au surfaces enables the removal of bulk layers while preserving the first layer attached to the electrode. With a proper choice of the applied potential, more than 90% of the bulk regions can be removed from large-area MoS2 crystals, as confirmed by atomic force microscopy, photoluminescence, and Raman spectroscopy. We further address a set of contributions that are helpful to elucidate the features of MoS2, namely, the hyphenation of electrochemistry and optical microscopy for real-time observation of the thinning process that was revealed to occur from the edges to the center of the flake, an image treatment to estimate the thinning area and thinning rate, and the preparation of free-standing MoS2 layers by electrochemically thinning bulk flakes on microhole-structured Ni/Au meshes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nicoliche2022,

title = {In Situ Nanocoating on Porous Pyrolyzed Paper Enables Antibiofouling and Sensitive Electrochemical Analyses in Biological Fluids},

author = {Caroline Y. N. Nicoliche and Aline M. Pascon and Ítalo R. S. Bezerra and Ana C. H. de Castro and Gabriel R. Martos and Jefferson Bettini and Wendel A. Alves and Murilo Santhiago and Renato S. Lima},

url = {https://pubs.acs.org/doi/abs/10.1021/acsami.1c18778},

doi = {10.1021/acsami.1c18778},

issn = {1944-8252},

year  = {2022},

date = {2022-01-19},

urldate = {2022-01-19},

journal = {ACS Appl. Mater. Interfaces},

volume = {14},

number = {2},

pages = {2522--2533},

publisher = {American Chemical Society (ACS)},

abstract = {Electrochemical detection in complex biofluids is a long-standing challenge as electrode biofouling hampers its sensing performance and commercial translation. To overcome this drawback, pyrolyzed paper as porous electrode coupled with the drop casting of an off-the-shelf polysorbate, that is, Tween 20 (T20), is described here by taking advantage of the in situ formation of a hydrophilic nanocoating (2 nm layer of T20). The latter prevents biofouling while providing the capillarity of samples through paper pores, leveraging redox reactions across both only partially fouled and fresh electrodic surfaces with increasing detection areas. The nanometric thickness of this blocking layer is also essential by not significantly impairing the electron-transfer kinetics. These phenomena behave synergistically to enhance the sensibility that further increases over long-term exposures (4 h) in biological fluids. While the state-of-the-art antibiofouling strategies compromise the sensibility, this approach leads to peak currents that are up to 12.5-fold higher than the original currents after 1 h exposure to unprocessed human plasma. Label-free impedimetric immunoassays through modular bioconjugation by directly anchoring spike protein on gold nanoparticles are also allowed, as demonstrated for the COVID-19 screening of patient sera. The scalability and simplicity of the platform combined with its unique ability to operate in biofluids with enhanced sensibility provide the generation of promising biosensing technologies toward real-world applications in point-of-care diagnostics, mass testing, and in-home monitoring of chronic diseases.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nicoliche2022b,

title = {In Situ Nanocoating on Porous Pyrolyzed Paper Enables Antibiofouling and Sensitive Electrochemical Analyses in Biological Fluids},

author = {Caroline Y. N. Nicoliche and Aline M. Pascon and Ítalo R. S. Bezerra and Ana C. H. de Castro and Gabriel R. Martos and Jefferson Bettini and Wendel A. Alves and Murilo Santhiago and Renato S. Lima},

url = {https://pubs.acs.org/doi/abs/10.1021/acsami.1c18778},

doi = {10.1021/acsami.1c18778},

issn = {1944-8252},

year  = {2022},

date = {2022-01-19},

urldate = {2022-01-19},

journal = {ACS Appl. Mater. Interfaces},

volume = {14},

number = {2},

pages = {2522--2533},

publisher = {American Chemical Society (ACS)},

abstract = {Electrochemical detection in complex biofluids is a long-standing challenge as electrode biofouling hampers its sensing performance and commercial translation. To overcome this drawback, pyrolyzed paper as porous electrode coupled with the drop casting of an off-the-shelf polysorbate, that is, Tween 20 (T20), is described here by taking advantage of the in situ formation of a hydrophilic nanocoating (2 nm layer of T20). The latter prevents biofouling while providing the capillarity of samples through paper pores, leveraging redox reactions across both only partially fouled and fresh electrodic surfaces with increasing detection areas. The nanometric thickness of this blocking layer is also essential by not significantly impairing the electron-transfer kinetics. These phenomena behave synergistically to enhance the sensibility that further increases over long-term exposures (4 h) in biological fluids. While the state-of-the-art antibiofouling strategies compromise the sensibility, this approach leads to peak currents that are up to 12.5-fold higher than the original currents after 1 h exposure to unprocessed human plasma. Label-free impedimetric immunoassays through modular bioconjugation by directly anchoring spike protein on gold nanoparticles are also allowed, as demonstrated for the COVID-19 screening of patient sera. The scalability and simplicity of the platform combined with its unique ability to operate in biofluids with enhanced sensibility provide the generation of promising biosensing technologies toward real-world applications in point-of-care diagnostics, mass testing, and in-home monitoring of chronic diseases.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hasimoto2021,

title = {Polydopamine nanofilms for high‐performance paper‐based electrochemical devices},

author = {Leonardo H. Hasimoto and Cátia C. Corrêa and Carlos A. R. Costa and Murilo Santhiago},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/bip.23472},

doi = {10.1002/bip.23472},

issn = {1097-0282},

year  = {2021},

date = {2021-12-00},

urldate = {2021-12-00},

journal = {Biopolymers},

volume = {112},

number = {12},

publisher = {Wiley},

abstract = {Since the discovery of polydopamine (PDA), there has been a lot of progress on using this substance to functionalize many different surfaces. However, little attention has been given to prepare functionalized surfaces for the preparation of flexible electrochemical paper-based devices. After fabricating the electrodes on paper substrates, we formed PDA on the surface of the working electrode using a chemical polymerization route. PDA nanofilms on carbon were characterized by contact angle (CA) experiments, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy (topography and electrical measurements) and electrochemical techniques. We observed that PDA introduces chemical functionalities (RNH2 and RC═O) that decrease the CA of the electrode. Moreover, PDA nanofilms did not block the heterogeneous electron transfer. In fact, we observed one of the highest standard heterogeneous rate constants (ks) for electrochemical paper-based electrodes (2.5 ± 0.1) × 10−3 cm s−1, which is an essential parameter to obtain larger currents. In addition, our results suggest that carbonyl functionalities are ascribed for the redox activity of the nanofilms. As a proof-of-concept, the electrooxidation of nicotinamide adenine dinucleotide showed remarkable features, such as, lower oxidation potential, electrocatalytic peak currents more than 30 times higher when compared to unmodified paper-based electrodes and electrocatalytic rate constant (kobs) of (8.2 ± 0.6) × 102 L mol−1 s−1.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Silva-Neto2021,

title = {Fully 3D printing of carbon black-thermoplastic hybrid materials and fast activation for development of highly stable electrochemical sensors},

author = {Habdias A. Silva-Neto and Murilo Santhiago and Lucas C. Duarte and Wendell K.T. Coltro},

url = {https://www.sciencedirect.com/science/article/abs/pii/S0925400521012892},

doi = {10.1016/j.snb.2021.130721},

issn = {0925-4005},

year  = {2021},

date = {2021-12-00},

urldate = {2021-12-00},

journal = {Sensors and Actuators B: Chemical},

volume = {349},

publisher = {Elsevier BV},

abstract = {3D printing technologies have emerged as powerful tools for the development of electrochemical sensors. However, pre-treatment methods are often required to improve electrochemical properties of 3D printed sensing surface to enable higher electroanalytical performance. Herein, we report a toxic-free method for rapid activation of 3D printed electrochemical sensors. The proposed pre-treatment involves a combination of photochemical and electrochemical oxidation processes to degrade the excess of binder material impregnated on the cell surface. This strategy is simple, fast and exposes the carbon black nanoparticles to facilitate the faradaic reactions. The reported method ensured long-term stability (~2 months) and high heterogeneous rate constants (1.2 ± 0.3 × 10−3 cm s−1). In addition, peak currents were remarkably increased up to 353 ± 13%, clearly highlighting the potential use these 3D electrodes for electroanalytical applications. The treated electrode offered low detection limits (at µmol L−1 levels) for different analytes including metals like Cd(II) (0.009) and Pb(II) (0.006), midazolam maleate (0.54) and uric acid (0.71). Based on the achieved results, the activated, stable, and fully 3D printed electrochemical cell is very promising towards a plethora of high-performance electroanalytical applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Fingolo2021b,

title = {Enhanced Hydrophobicity in Nanocellulose-Based Materials: Toward Green Wearable Devices},

author = {Ana C. Fingolo and Vitória B. de Morais and Saionara V. Costa and Cátia C. Corrêa and Beatriz Lodi and Murilo Santhiago and Juliana S. Bernardes and Carlos C. B. Bufon},

url = {https://pubs.acs.org/doi/abs/10.1021/acsabm.1c00317},

doi = {10.1021/acsabm.1c00317},

issn = {2576-6422},

year  = {2021},

date = {2021-09-20},

urldate = {2021-09-20},

journal = {ACS Appl. Bio Mater.},

volume = {4},

number = {9},

pages = {6682--6689},

publisher = {American Chemical Society (ACS)},

abstract = {Nanocellulose is a promising material for fabricating green, biocompatible, flexible, and foldable devices. One of the main issues of using nanocellulose as a fundamental component for wearable electronics is the influence of environmental conditions on it. The water adsorption promotes the swelling of nanopaper substrates, which directly affects the devices’ electrical properties prepared on/with it. Here, plant-based nanocellulose substrates, and ink composites deposited on them, are chemically modified using hexamethyldisilazane to enhance the system’s hydrophobicity. After the treatment, the electrical properties of the devices exhibit stable operation under humidity levels around 95%. Such stability demonstrates that the hexamethyldisilazane modification substantially suppresses the water adsorption on fundamental device structures, namely, substrate plus conducting ink. These results attest to the robustness necessary to use nanocellulose as a key material in wearable devices such as electronic skins and tattoos and contribute to the worldwide efforts to create biodegradable devices engineered in a more deterministic fashion.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Shimizu2021,

title = {Alcohol-Triggered Capillarity through Porous Pyrolyzed Paper-Based Electrodes Enables Ultrasensitive Electrochemical Detection of Phosphate},

author = {Flavio M. Shimizu and Anielli M. Pasqualeti and Caroline Y. N. Nicoliche and Angelo L. Gobbi and Murilo Santhiago and Renato S. Lima},

url = {https://pubs.acs.org/doi/abs/10.1021/acssensors.1c01302},

doi = {10.1021/acssensors.1c01302},

issn = {2379-3694},

year  = {2021},

date = {2021-08-27},

urldate = {2021-08-27},

journal = {ACS Sens.},

volume = {6},

number = {8},

pages = {3125--3132},

publisher = {American Chemical Society (ACS)},

abstract = {The sensing field has shed light on an urgent necessity for field-deployable, user-friendly, sensitive, and scalable platforms that are able to translate solutions into the real world. Here, we attempt to meet these requests by addressing a simple, low-cost, and fast electrochemical approach to provide sensitive assays that consist of dropping a small volume (0.5 μL) of off-the-shelf alcohols on pyrolyzed paper-based electrodes before adding the sample (150 μL). This method was applied in the detection of phosphate after the formation of the phosphomolybdate complex (250–860 nm in size). Prior drops of isopropanol allow for the fast penetration of the sample through pores of this hydrophobic paper, delivering hindrance-free redox reactions across increasing active areas and ultimately improving the detection performance. The sensitivity (−1.9 10–6 mA cm–2 ppb–1) and limit of detection (1.1 ppb) were improved, respectively, by factors of 33 and 99 over the data achieved without the addition of isopropanol, listing among the lowest values when compared with those results reported in the literature for phosphate (expressed in terms of the concentration of phosphorus). The approach enabled the quantification of this analyte in real samples with accuracies ranging from 87 to 103%. Furthermore, preliminary measurements demonstrated the successful performance of the electrodes with prior addition of other widely used alcohols, that is, methanol and ethanol. These results may extend the applicability of the method. In special, the scalability and eco-friendly character of the electrode fabrication combined with the sensitivity and simplicity of the analyses make the developed platform a promising alternative that may help to pave the way for a new generation of disposable sensors toward the daily monitoring of phosphate in water samples, thus contributing to prevent ecological side effects.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Giordano2021,

title = {Bifunctional Metal Meshes Acting as a Semipermeable Membrane and Electrode for Sensitive Electrochemical Determination of Volatile Compounds},

author = {Gabriela F. Giordano and Vitoria M. S. Freitas and Gabriel R. Schleder and Murilo Santhiago and Angelo L. Gobbi and Renato S. Lima},

url = {https://pubs.acs.org/doi/abs/10.1021/acsami.1c07874},

doi = {10.1021/acsami.1c07874},

issn = {1944-8252},

year  = {2021},

date = {2021-08-04},

urldate = {2021-08-04},

journal = {ACS Appl. Mater. Interfaces},

volume = {13},

number = {30},

pages = {35914--35923},

publisher = {American Chemical Society (ACS)},

abstract = {The monitoring of toxic inorganic gases and volatile organic compounds has brought the development of field-deployable, sensitive, and scalable sensors into focus. Here, we attempted to meet these requirements by using concurrently microhole-structured meshes as (i) a membrane for the gas diffusion extraction of an analyte from a donor sample and (ii) an electrode for the sensitive electrochemical determination of this target with the receptor electrolyte at rest. We used two types of meshes with complementary benefits, i.e., Ni mesh fabricated by robust, scalable, and well-established methods for manufacturing specific designs and stainless steel wire mesh (SSWM), which is commercially available at a low cost. The diffusion of gas (from a donor) was conducted in headspace mode, thus minimizing issues related to mesh fouling. When compared with the conventional polytetrafluoroethylene (PTFE) membrane, both the meshes (40 μm hole diameter) led to a higher amount of vapor collected into the electrolyte for subsequent detection. This inedited fashion produced a kind of reverse diffusion of the analyte dissolved into the electrolyte (receptor), i.e., from the electrode to bulk, which further enabled highly sensitive analyses. Using Ni mesh coated with Ni(OH)2 nanoparticles, the limit of detection reached for ethanol was 24-fold lower than the data attained by a platform with a PTFE membrane and placement of the electrode into electrolyte bulk. This system was applied in the determination of ethanol in complex samples related to the production of ethanol biofuel. It is noteworthy that a simple equation fitted by machine learning was able to provide accurate assays (accuracies from 97 to 102%) by overcoming matrix effect-related interferences on detection performance. Furthermore, preliminary measurements demonstrated the successful coating of the meshes with gold films as an alternative raw electrode material and the monitoring of HCl utilizing Au-coated SSWMs. These strategies extend the applicability of the platform that may help to develop valuable volatile sensing solutions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}