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13
result(s) for
"Quintana, Mildred"
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Chemically Functionalized 2D Transition Metal Dichalcogenides for Sensors
by
Quintana, Mildred
,
Acosta, Selene
in
2D transition metal dichalcogenides
,
Adsorption
,
Biosensors
2024
The goal of the sensor industry is to develop innovative, energy-efficient, and reliable devices to detect molecules relevant to economically important sectors such as clinical diagnoses, environmental monitoring, food safety, and wearables. The current demand for portable, fast, sensitive, and high-throughput platforms to detect a plethora of new analytes is continuously increasing. The 2D transition metal dichalcogenides (2D-TMDs) are excellent candidates to fully meet the stringent demands in the sensor industry; 2D-TMDs properties, such as atomic thickness, large surface area, and tailored electrical conductivity, match those descriptions of active sensor materials. However, the detection capability of 2D-TMDs is limited by their intrinsic tendency to aggregate and settle, which reduces the surface area available for detection, in addition to the weak interactions that pristine 2D-TMDs normally exhibit with analytes. Chemical functionalization has been proposed as a consensus solution to these limitations. Tailored surface modification of 2D-TMDs, either by covalent functionalization, non-covalent functionalization, or a mixture of both, allows for improved specificity of the surface–analyte interaction while reducing van der Waals forces between 2D-TMDs avoiding agglomeration and precipitation. From this perspective, we review the recent advances in improving the detection of biomolecules, heavy metals, and gases using chemically functionalized 2D-TMDs. Covalent and non-covalent functionalized 2D-TMDs are commonly used for the detection of biomolecules and metals, while 2D-TMDs functionalized with metal nanoparticles are used for gas and Raman sensors. Finally, we describe the limitations and further strategies that might pave the way for miniaturized, flexible, smart, and low-cost sensing devices.
Journal Article
Carbon-based nanomaterials: interactions with cells, brain therapies, and neural sensing
2025
Carbon nanomaterials (CNMs) are characterized by their extensive surface area and extraordinary electronic, thermal, and chemical properties, offering an innovative potential for biomedical applications. The physicochemical properties of CNMs can be fine-tuned through chemical functionalization to design the bio-nano interface, allowing for controlled biocompatibility or specific bioactivity. This versatility offers a transformative approach to addressing the inherent limitations of conventional brain therapies, which frequently demonstrate low efficacy and significant adverse effects. This review delves into recent advances in understanding the intricate interactions between carbon nanostructures and cellular systems, highlighting their activity in brain therapy and neuronal sensing. We provide a comprehensive analysis of key nanostructures, including few-layer graphene (FLG), graphene oxide (GO), graphene quantum dots (GQD), single- and multi-walled carbon nanotubes (SWCNT and MWCNT), carbon nanohorns (CNH), carbon nanodiamonds (CNDs), and fullerenes (C60). Their unique atomic configurations and surface modifications are examined, revealing the underlying mechanisms that drive their biomedical applications. This review highlights how a deep understanding of the interactions between CNMs and cells can catalyze innovative neurotherapeutic solutions. By leveraging their unique properties, CNMs address critical challenges such as crossing the blood–brain barrier, improving therapeutic accuracy, and minimizing side effects. These advances have the potential to significantly improve the treatment outcomes of brain disorders, paving the way for a new era of targeted and effective neurological interventions.
Journal Article
Plasma-Sputtered Growth of Ni-Pd Bimetallic Nanoparticles on Carbon Nanotubes for Toluene Sensing
by
Quintana, Mildred
,
Acosta, Selene
,
Casanova-Chafer, Juan
in
Atoms & subatomic particles
,
bimetallic nanoparticles
,
Bimetals
2023
The properties of carbon nanotubes (CNTs) can be effectively tailored by decorating their surface with metal nanoparticles. For the decoration, first plasma functionalization is used to add oxygen chemical groups to the CNTs surface. Afterwards, the Ox-CNTs are decorated with Ni-Pd bimetallic nanoparticles using plasma sputtering deposition, a clean, fast, and environmentally friendly functionalization method. The grafted oxygen groups serve as nucleation sites for the growth of the bimetallic nanoparticles. Finally, the Ni-Pd nanoparticle-decorated CNTs are assessed as a sensing layer for the detection of toluene.
Journal Article
Doping engineering of lithium-aluminum layered double hydroxides for high-efficiency lithium extraction from salt lake brines
by
Zhang, Lingjie
,
Quintana, Mildred
,
Lv, Shuaike
in
Adsorption
,
Aluminum
,
Atomic/Molecular Structure and Spectra
2024
Lithium-aluminum layered double hydroxides (LiAl-LDH) have been be successfully applied in commercial-scale for lithium extraction from salt lake brine, however, further advancement of their applications is hampered by suboptimal Li+ adsorption performance and ambiguous extraction process. Herein, a doping engineering strategy was developed to fabricate novel Zn
2+
-doped LiAl-LDH (LiZnAl-LDH) with remarkable higher Li
+
adsorption capacity (13.4 mg/g) and selectivity (separation factors of 213, 834, 171 for Li
+
/K
+
, Li
+
/Na
+
, Li
+
/Mg
2+
, respectively), as well as lossless reusability in Luobupo brine compared to the pristine LiAl-LDH. Further, combining experiments and simulation calculations, it was revealed that the specific surface area, hydrophilic, and surface attraction for Li
+
of LiZnAl-LDH were significantly improved, reducing the adsorption energy (
E
ad
) and Gibbs free energy (ΔG), thus facilitating the transfer of Li
+
from brine into interface followed by insertion into voids. Importantly, the intrinsic oxygen vacancies derived from Zn-doping depressed the diffusion energy barrier of Li
+
, which accelerated the diffusion process of Li
+
in the internal bulk of LiZnAl-LDH. This work provides a general strategy to overcome the existing limitations of Li
+
recovery and deepens the understanding of Li
+
extraction on LiAl-LDH.
Journal Article
A few-layer graphene/chlorin e6 hybrid nanomaterial and its application in photodynamic therapy against Candida albicans
by
Hernández-Sánchez, Dania
,
Quintana, Mildred
,
Moreno-Aguilar, Carlos
in
Antibiotics
,
Biocompatibility
,
chlorin e6
2020
The global emergence of multidrug resistance of fungal infections and the decline in the discovery of new antibiotics are increasingly prevalent causes of hospital-acquired infections, among other major challenges in the global health care sector. There is an urgent need to develop noninvasive, nontoxic, and new antinosocomial approaches that work more effectively and faster than current antibiotics. In this work, we report on a biocompatible hybrid nanomaterial composed of few-layer graphene and chlorin e6 (FLG-Ce6) for the photodynamic treatment (PDT) of
Candida albicans
. We show that the FLG-Ce6 hybrid nanomaterial displays enhanced reactive oxygen species (ROS) generation compared with Ce6. The enhancement is up to 5-fold when irradiated for 15 min at 632 nm with a red light-emitting diode (LED). The viability of
C. albicans
in the presence of FLG-Ce6 was measured 48 h after photoactivation. An antifungal effect was observed only when the culture/FLG-Ce6 hybrid was exposed to the light source.
C. albicans
is rendered completely unviable after exposure to ROS generated by the excited FLG-Ce6 hybrid nanomaterial. An increased PDT effect was observed with the FLG-Ce6 hybrid nanomaterial by a significant reduction in the viability of
C. albicans
, by up to 95%. This is a marked improvement compared to Ce6 without FLG, which reduces the viability of
C. albicans
to only 10%. The antifungal action of the hybrid nanomaterial can be activated by a synergistic mechanism of energy transfer of the absorbed light from Ce6 to FLG. The novel FLG-Ce6 hybrid nanomaterial in combination with the red LED light irradiation can be used in the development of a wide range of antinosocomial devices and coatings.
Journal Article
Interactions of Functionalized Multi-Wall Carbon Nanotubes with Giant Phospholipid Vesicles as Model Cellular Membrane System
by
Aranda-Espinoza, Said
,
Pérez-Luna, Verónica
,
Moreno-Aguilar, Carlos
in
639/301/923/966
,
639/925/357/73
,
Carbon
2018
Carbon Nanotubes (CNTs) are considered alternative materials for the design of advanced drug and gene delivery vectors. However, the mechanism responsible for the cellular membrane intake of CNTs is not well understood. In the present study, we show how multi-walled carbon nanotubes (MWCNTs) owning different surface properties, interact with giant unilamellar vesicles (GUVs), a simple model system for cellular membranes. In particular, we want to address the hydrophilic/hydrophobic interactions between MWCNTs and lipid membranes and the subsequent mechanical properties changes of the systems. In order to elucidate this interaction, we made the following chemical modifications on MWCNTs: oxidized MWCNTs (ox-MWCNTs) displaying reduced hydrophobic surface character, pristine MWCNTs (p-MWCNTs), and alkyl functionalized MWCNTs (alk-MWCNTs) exhibiting enhanced hydrophobic surface properties, were put in contact with GUVs and observed by confocal microscopy. Our observations revealed that the interaction between the CNTs and GUVs depends on the type of chemical functionalization: ox-MWCNTs remain at the membrane interacting with the polar head of the phospholipids, p-MWCNTs internalize GUVs spontaneously, and alk-MWCNTs persist inside the membrane. The mechanical properties of
MWCNTs@GUVs
systems were measured using the electrodeformation method, which shows an increased bending stiffness (
κ
) of the GUVs as MWCNTs concentration increases. High concentrations of p-MWCNTs and alk-MWCNTs induced vesicle adhesion; p-MWCNTs produced a considerable reduction in the average size of the GUVs, while alk-MWCNTs form complex stable structures inside the membrane. The statistical analyses of the experimental results are compared with available computer simulations. The picture emerging from our results is that the interaction between GUVs and MWCNTs is due mainly to hydrophobicity.
Journal Article
Improving the Flotation of Unoxidized and Oxidized Molybdenite Fines Using Dodecylamine as a Collector: Flotation Tests and Interaction Mechanism
2024
The flotation of unoxidized and oxidized molybdenite fines is a challenging job worldwide. In this work, dodecylamine (DDA) was developed as a potential collector to improve the flotation of molybdenite fines with and without oxidation. The flotation behaviors and interaction mechanisms were probed through flotation tests, contact angle, Zeta potential, Scanning Electron Microscope-Energy Dispersive Spectrometer(SEM-EDS), and X-ray Photoelectron Spectroscopy (XPS). The flotation tests revealed that DDA improved the flotation of unoxidized or oxidized molybdenite fines efficiently. The results of Zeta potential, contact angle, and SEM-EDS uncovered that a substantial number of DDA species adsorbed on both fresh and oxidized molybdenite faces and edges, thus enhancing their hydrophobicity. XPS analysis further manifested that RNH2 and RNH3+ adsorbed on the S atoms of fresh faces through hydrogen bonding. Meanwhile, RNH2 and RNH3+ mainly adsorbed on fresh edges via chemical bonding between amine groups and Mo sites and electrostatic force. For oxidized molybdenite, RNH2 and RNH3+ interacted with oxidized faces through hydrogen bonding while adsorbed on oxidized edges via hydrogen bonding and electrostatic interaction.
Journal Article
Synthesis and Characterization of a New Collagen-Alginate Aerogel for Tissue Engineering
by
Quintana, Mildred
,
Escobar-García, Diana María
,
Flores-Reyes, Hector
in
Aerogels
,
Alginates
,
Biocompatibility
2019
Scaffolds have been used as extracellular matrix analogs to promote cell migration, cell attachment, and cell proliferation. The use of aerogels and carbon-based nanomaterials has recently been proposed for tissue engineering due to their properties. The aim of this study is to develop a highly porous collagen-alginate(-graphene oxide) aerogel-based scaffold. The GO synthesis was performed by Hummers method; a collagen-alginate and collagen-alginate-GO hydrogel were synthetized; then, they were treated by a supercritical drying process. The aerogels obtained were evaluated by SEM and FTIR. Osteoblasts were seeded over the scaffolds and evaluated by SEM. According to the characterization, the aerogels showed a highly porous interconnected network covered by a nonporous external wall. According to the FTIR, the chemical functional groups of collagen and GO were maintained after the supercritical process. The SEM images after cell culture showed that a collagen-alginate scaffold promotes cell attachment and proliferation. The alginate-collagen aerogel-based scaffold could be a platform for tissue engineering since it shows adequate properties. Further studies are needed to determine the cell interactions with GO.
Journal Article
Low Kinetic Energy Oxygen Ion Irradiation of Vertically Aligned Carbon Nanotubes
by
Sierra Castillo, Ayrton
,
Quintana, Mildred
,
Snyders, Rony
in
Carbon
,
Chemical Sciences
,
Chemical vapor deposition
2019
Vertically aligned multiwalled carbon nanotubes (v-CNTs) were functionalized with oxygen groups using low kinetic energy oxygen ion irradiation. X-ray photoelectron spectroscopy (XPS) analysis indicates that oxygen ion irradiation produces three different types of oxygen functional groups at the CNTs surface: epoxide, carbonyl and carboxyl groups. The relative concentration of these groups depends on the parameters used for oxygen ion irradiation. Scanning electron microscopy (SEM) shows that the macroscopic structure and alignment of v-CNTS are not affected by the ion irradiation and transmission electron microscopy (TEM) proves tip functionalization of v-CNTs. We observed that in comparison to oxygen plasma treatment, oxygen ion irradiation shows higher functionalization efficiency and versatility. Ion irradiation leads to higher amount of oxygen grafting at the v-CNTs surface, besides different functional groups and their relative concentration can be tuned varying the irradiation parameters.
Journal Article