Microfluid biosensor for detection of hpv in patient scraping samples: Determining E6 and E7 oncogenes.

E6 and E7 oncogenes are pivotal in the carcinogenic transformation in HPV infections and efficient diagnostic methods can ensure the detection and differentiation of HPV genotype. This study describes the development and validation of an electrochemical, label-free genosensor coupled with a microfluidic system for detecting the E6 and E7 oncogenes in cervical scraping samples. The nanostructuring employed was based on a cysteine and graphene quantum dots layer that provides functional groups, surface area, and interesting electrochemical properties. Biorecognition tests with cervical scraping samples showed differentiation in the voltammetric response. Low-risk HPV exhibited a lower biorecognition response, reflected in ΔI% values of 82.33 % ± 0.29 for HPV06 and 80.65 % ± 0.68 for HPV11 at a dilution of 1:100. Meanwhile, high-risk, HPV16 and HPV18, demonstrated ΔI% values of 96.65 % ± 1.27 and 93 % ± 0.026, respectively, at the same dilution. Therefore, the biorecognition intensity followed the order: HPV16 >HPV18 >HPV06 >HPV11. The limit of detection and the limit of quantification of E6E7 microfluidic LOC-Genosensor was 26 fM, and 79.6 fM. Consequently, the E6E7 biosensor is a valuable alternative for clinical HPV diagnosis, capable of detecting the potential for oncogenic progression even in the early stages of infection.

Sol-Gel Synthesis of TiO2 with Pectin and Their Efficiency in Solar Cells Sensitized by Quantum Dots.

In this study, titanium oxide TiO2 nanoparticles were produced using the sol-gel approach of green synthesis with pectin as the reducing agent. The synthetized TiO2 nanoparticles with pectin were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), visible light absorption (UV-Vis) and the BET method. The structure and morphology of the TiO2 powder were described with SEM, revealing uniform monodisperse grains with a distribution of 80% regarding sizes < 250 nm; the resulting crystal phase of synthetized TiO2 was identified as an anatase and rutile phase with a crystallinity size estimated between 27 and 40 nm. Also, the surface area was determined by nitrogen adsorption-desorption using the Brown-Emmet-Teller method, with a surface area calculated as 19.56 m2/g, typical of an IV type isotherm, indicating mesoporous NPs. UV-Vis spectra showed that sol-gel synthesis reduced the band gap from the 3.2 eV common value to 2.22 eV after estimating the optical band gap energy using the adsorption coefficient; this translates to a possible extended photo response to the visible region, improving photoactivity. In addition, the power conversion of the photoelectrode was compared based on similar assembly techniques of TiO2 electrode deposition. Quantum dot crystals were deposited ionically on the electrode surface, as two different paste formulations based on a pectin emulsifier were studied for layer deposition. The results confirm that the TiO2 paste with TiO2-synthesized powder maintained good connections between the nanocrystalline mesoporous grains and the deposited layers, with an efficiency of 1.23% with the transparent paste and 2.27% with the opaque paste. These results suggest that pectin could be used as a low-cost, functional sol-gel catalysis agent for the synthesis of controlled NPs of metal oxide. It demonstrates interesting optical properties, such as an increase in photo response, suggesting further applications to photocatalysts and biomedical features.

Influence of Structural Properties of Oleic Acid-Capped CdSe/ZnS Quantum Dots in the Detection of Hg2+ Ions.

Oleic acid-capped CdSe/ZnS quantum dots (QDs) were used to investigate their photoluminescence (PL) response to Hg2+ ions as a function of the surface properties of QDs. Three distinctly-size CdSe/ZnS QDs were obtained by varying the molar ratio of shell precursors, which were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), Fourier-Transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), absorption spectroscopy, and time-resolved fluorescence spectroscopy. Results revealed the obtention of zinc blende nanocrystals with sizes ranging from 2.7 to 3.2 nm (± 0.5) and ZnS thickness between 0.3 and 1.0 monolayer (ML). The variation of the [S]/[Zn] molar ratio introduced chemical species that act as traps, affecting the PL properties differently. Depending on the thickness of the shell and chemical speciation on surface, Hg2+ ions could induce quenching or enhancement of PL. Detection of mercury ions was evaluated in terms of Stern-Volmer equation, where the limit of detection (LOD) for the PL quenching system was 11.2 nM, while for the PL enhancing systems were 8.98 nM and 10.7 nM. Results demonstrate the performance of oleic acid-capped CdSe/ZnS QDs to detect Hg2+ and their capacity to turn the PL on/off depending on surface properties.

Pt-based graphene quantum dots for water dissociation.

It is widely recognized that Pt nanostructures exhibit favorable catalytic properties for several important technological reactions. Furthermore, selecting an appropriate support has the potential to enhance the catalytic activity of these materials. In this study, we investigate Pt nanoparticles deposited on quantum dots using quantum chemical calculations. We explore the utilization of low-dimensional carbonaceous support by employing graphene quantum dots (GQDs), which offer abundant active sites, such as edges, and diverse conformations. This provides excellent tuning possibilities for both chemical and physical properties. Our goal is to gather information on the alterations in electronic properties, charge redistribution and reactivity of platinum particles on GQD, also analyzing their potential role as catalysts in the water dissociation reaction. Based on thermodynamic and kinetic considerations, our calculations suggest that a Pt3nanoparticle adsorbed on the edge of the GQD exhibits favorable energetics, leading to a promising catalytic material.

Disposable electrochemical sensor: Highly sensitive determination of nitrofurazone antibiotic in environmental samples and pharmaceutical formulations.

The study presents the successful development of a new electrochemical sensor with low cost and disposability for application in nitrofurazone detection in environmental and pharmaceutical samples. The sensors were fabricated using materials obtained from local storage and conductive carbon ink. The modification of the screen-printed electrodes with the hybrid nanomaterial based on silver nanoparticles, carbon quantum dots, and carbon nanotubes showed synergistic contributions in the nitrofurazone electrooxidation, as observed in the wide linear range (0.008 at 15.051 µM), with a sensitivity of 0.650 µA/µM. The limit of detection obtained was 4.6 nM. Differential pulse voltammetry, cyclic voltammetry, X-ray photoelectron spectroscopy, X-ray diffraction analysis, and high-resolution transmission electron microscopy were used to evaluate the electrochemical and structural characteristics. Studies of possible interferences were considered with nitrofurazone in the presence of the ions and organic molecules. The results were satisfactory, with a variation of 93.3% ± 4.39% at 100% ± 2.40%. The low volume used in the analyses (50 µL), disposability, high sensibility, selectivity, and low limit of detection are advantages that make the proposed sensor an electrochemical tool of high viability for the NFZ detection in environmental matrices and pharmaceutical formulations.

Molecular interactions of the Omicron, Kappa, and Delta SARS-CoV-2 spike proteins with quantum dots of graphene oxide.

CONTEXT: The Omicron, Kappa, and Delta variants are different strains of the SARS-CoV-2 virus. Graphene oxide quantum dots (GOQDs) represent a burgeoning class of oxygen-enriched, zero-dimensional materials characterized by their sub-20-nm dimensions. Exhibiting pronounced quantum confinement and edge effects, GOQDs manifest exceptional physical-chemical attributes. This study delves into the potential of graphene oxide quantum dots, elucidating their inherent properties pertinent to the surface structures of SARS-CoV-2, employing an integrated computational approach for the repositioning of inhibitory agents. METHODS: Following rigorous adjustment tests, a spectrum of divergent bonding conformations emerged, with particular emphasis placed on identifying the conformation exhibiting optimal adjustment scores and interactions. The investigation employed molecular docking simulations integrating affinity energy evaluations, electrostatic potential clouds, molecular dynamics encompassing average square root calculations, and the computation of Gibbs-free energy. These values quantify the strength of interaction between GOQDs and SARS-CoV-2 spike protein variants. The receptor structures were optimized using the CHARM-GUI server employing force field AMBERFF14SB. The algorithm embedded in CHARMM offers an efficient interpolation scheme and automatic step size selection, enhancing the efficiency of the optimization process. The 3D structures of the ligands are constructed and optimized with density functional theory (DFT) method based on the most stable conformer of each binder. Autodock Vina Software (ADV) was utilized, where essential parameters were specified. Electrostatic potential maps (MEPs) provide a visual depiction of molecules' charge distributions and related properties. After this, molecular dynamics simulations employing the CHARM36 force field in Gromacs 2022.2 were conducted to investigate GOs' interactions with surface macromolecules of SARS-CoV-2 in an explicit aqueous environment. Furthermore, our investigation suggests that lower values indicate stronger binding. Notably, GO-E consistently showed the most negative values across interactions with different variants, suggesting a higher affinity compared to other GOQDs (GO-A to GO-D).

Simultaneous Detection of Carbon Quantum Dots as Tracers for Interwell Connectivity Evaluation in a Pattern with Two Injection Wells.

This study aimed to develop and implement a nanotechnology-based alternative to traditional tracers used in the oil and gas industry for assessing interwell connectivity. A simple and rapid hydrothermal protocol for synthesizing carbon quantum dots (CQDs) using agroindustry waste was implemented. Three commercial CQDs were employed (CQDblue, CQDgreen, and CQDred); the fourth was synthesized from orange peel (CQDop). The CQDs from waste and other commercials with spherical morphology, nanometric sizes less than 11 nm in diameter, and surface roughness less than 3.1 nm were used. These tracers demonstrated high colloidal stability with a negative zeta potential, containing carbonyl-type chemical groups and unsaturations in aromatic structures that influenced their optical behavior. All materials presented high colloidal stability with negative values of charge z potential between -17.8 and -49.1. Additionally, individual quantification of these tracers is feasible even in scenarios where multiple CQDs are present in the effluent with a maximum percentage of interference of 15.5% for CQDop in the presence of the other three nanotracers. The CQDs were injected into the field once the technology was insured under laboratory conditions. Monitoring the effluents allowed the determination of connectivity for five first-line producer wells. This study enables the application of CQDs in the industry, particularly in fields where the arrangement of injector and producer wells is intricate, requiring the use of multiple tracers for a comprehensive description of the system.

Physico-Chemical Properties of CdTe/Glutathione Quantum Dots Obtained by Microwave Irradiation for Use in Monoclonal Antibody and Biomarker Testing.

In this report, we present the results on the physicochemical characterization of cadmium telluride quantum dots (QDs) stabilized with glutathione and prepared by optimizing the synthesis conditions. An excellent control of emissions and the composition of the nanocrystal surface for its potential application in monoclonal antibody and biomarker testing was achieved. Two samples (QDYellow, QDOrange, corresponding to their emission colors) were analyzed by dynamic light scattering (DLS), and their hydrodynamic sizes were 6.7 nm and 19.4 nm, respectively. Optical characterization by UV-vis absorbance spectroscopy showed excitonic peaks at 517 nm and 554 nm. Photoluminescence spectroscopy indicated that the samples have a maximum intensity emission at 570 and 606 nm, respectively, within the visible range from yellow to orange. Infrared spectroscopy showed vibrational modes corresponding to the functional groups OH-C-H, C-N, C=C, C-O, C-OH, and COOH, which allows for the formation of functionalized QDs for the manufacture of biomarkers. In addition, the hydrodynamic radius, zeta potential, and approximate molecular weight were determined by dynamic light scattering (DLS), electrophoretic light scattering (ELS), and static light scattering (SLS) techniques. Size dispersion and the structure of nanoparticles was obtained by Transmission Electron Microscopy (TEM) and by X-ray diffraction. In the same way, we calculated the concentration of Cd2+ ions expressed in mg/L by using the Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-OES). In addition to the characterization of the nanoparticles, the labeling of murine myeloid cells was carried out with both samples of quantum dots, where it was demonstrated that quantum dots can diffuse into these cells and connect mostly with the cell nucleus.

Fentogram electrochemical detection of HIV RNA based on graphene quantum dots and gold nanoparticles.

This work reports the construction of an HIV-specific genosensor through the modification of carbon screen-printed electrodes (CSPE) with graphene quantum dots decorated with L-cysteine and gold nanoparticles (cys-GQDs/AuNps). Cys-GQDs were characterized by FT-IR and UV-vis spectra and electronic properties of the modified electrodes were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. The modification of the electrode surface with cys-GQDs and AuNps increased the electrochemical performance of the electrode, improving the electron transfer of the anionic redox probe [Fe(CN)6]3-/4- on the electrochemical platform. When compared to the bare surface, the modified electrode showed a 1.7 times increase in effective electrode area and a 29 times decrease in charge transfer resistance. The genosensor response was performed by differential pulse voltammetry, monitoring the current response of the anionic redox probe, confirmed with real genomic RNA samples, making it possible to detect 1 fg/mL. In addition, the genosensor maintained its response for 60 days at room temperature. This new genosensor platform for early detection of HIV, based on the modification of the electrode surface with cys-GQDs and AuNps, discriminates between HIV-negative and positive samples, showing a low detection limit, as well as good specificity and stability, which are relevant properties for commercial application of biosensors.

Minicells as an Escherichia coli mechanism for the accumulation and disposal of fluorescent cadmium sulphide nanoparticles.

BACKGROUND: Bacterial biosynthesis of fluorescent nanoparticles or quantum dots (QDs) has emerged as a unique mechanism for heavy metal tolerance. However, the physiological pathways governing the removal of QDs from bacterial cells remains elusive. This study investigates the role of minicells, previously identified as a means of eliminating damaged proteins and enhancing bacterial resistance to stress. Building on our prior work, which unveiled the formation of minicells during cadmium QDs biosynthesis in Escherichia coli, we hypothesize that minicells serve as a mechanism for the accumulation and detoxification of QDs in bacterial cells. RESULTS: Intracellular biosynthesis of CdS QDs was performed in E. coli mutants ΔminC and ΔminCDE, known for their minicell-producing capabilities. Fluorescence microscopy analysis demonstrated that the generated minicells exhibited fluorescence emission, indicative of QD loading. Transmission electron microscopy (TEM) confirmed the presence of nanoparticles in minicells, while energy dispersive spectroscopy (EDS) revealed the coexistence of cadmium and sulfur. Cadmium quantification through flame atomic absorption spectrometry (FAAS) demonstrated that minicells accumulated a higher cadmium content compared to rod cells. Moreover, fluorescence intensity analysis suggested that minicells accumulated a greater quantity of fluorescent nanoparticles, underscoring their efficacy in QD removal. Biosynthesis dynamics in minicell-producing strains indicated that biosynthesized QDs maintained high fluorescence intensity even during prolonged biosynthesis times, suggesting continuous QD clearance in minicells. CONCLUSIONS: These findings support a model wherein E. coli utilizes minicells for the accumulation and removal of nanoparticles, highlighting their physiological role in eliminating harmful elements and maintaining cellular fitness. Additionally, this biosynthesis system presents an opportunity for generating minicell-coated nanoparticles with enhanced biocompatibility for diverse applications.

Acid selenites as new selenium precursor for CdSe quantum dot synthesis.

Chemical precursors for nanomaterials synthesis have become essential to tune particle size, composition, morphology, and unique properties. New inexpensive precursors investigation that precisely controls these characteristics is highly relevant. We studied new Se precursors, the acid selenites (R-O-SeOOH), to synthesize CdSe quantum dots (QDs). They were produced at room temperature by the Image 1 reaction with alcohols having different alkyl chains and were characterized by 1H NMR confirming their structures. This unprecedented precursor generates high-quality CdSe nanocrystals with narrow size distribution in the zinc-blend structure showing controlled optical properties. Advanced characterization detailed the CdSe structure showing stacking fault defects and its dependence on the used R-O-SeOOH. The QDs formation was examined using a time-dependent growth kinetics model. Differences in the nanoparticle surface structure influenced the optical properties, and they were correlated to the Se-precursor nature. Small alkyl chain acid selenites generally lead to more controlled QDs morphology, while the bigger alkyl chain leads to slightly upper quantum yields. Acid selenites can potentially replace Se-precursors at competitive costs in the metallic chalcogenide nanoparticles. Image 1 is chemically stable, and alcohols are cheap and less toxic than the reactants used today, making acid selenites a more sustainable Se precursor.

Second-Order Nonlinearity of Graphene Quantum Dots Measured by Hyper-Rayleigh Scattering.

The first hyperpolarizability of graphene quantum dots (GQDs) suspended in water was determined using the hyper-Rayleigh scattering (HRS) technique. To the best of our knowledge, this is the first application of the HRS technique to characterize GQDs. Two commercial GQDs (Acqua-Cyan and Acqua-Green) with different compositions were studied. The HRS experiments were performed with an excitation laser at 1064 nm. The measured hyperpolarizabilities were (1.0±0.1)×10-27 esu and (0.9±0.1)×10-27 esu for Acqua-Cyan and Acqua-Green, respectively. The results were used to estimate the hyperpolarizability per nanosheet obtained by assuming that each GQD has five nanosheets with 0.3 nm thickness. The two-level model, used to calculate the static hyperpolarizability per nanosheet, provides values of (2.4±0.1)×10-28 esu (Acqua-Cyan) and (0.5±0.1)×10-28 esu (Aqua-Green). The origin of the nonlinearity is discussed on the basis of polarized resolved HRS experiments, and electric quadrupolar behavior with a strong dependence on surface effects. The nontoxic characteristics and order of magnitude indicate that these GQDs may be useful for biological microscopy imaging.

Short-pulsed Q-switched fiber laser using graphene oxide quantum dots based as saturable absorber.

In this work, we report the experimental study of a Q-switched optical fiber laser based on graphene oxide quantum dots (GOQDs) as saturable absorber (SA). GOQDs are fabricated by carbonization and exfoliation electrospun polyacrylonitrile (PAN) fibers. The results of Fourier Transform Infrared Spectroscopy (FTIR) showed bands caused by the CHs and C[bond, double bond]O groups associated with the GOQDs. The Raman spectrum showed the typical G and D bands of GOQDs. The size of the GOQDs, calculated by Transmission Electron Microscopy (TEM) was 6 nm; additionally, by high resolution TEM (HRTEM), an interplanar distance of 0.19 nm corresponding to the (002) direction of the graphene oxide was calculated. The SA was achieved using the photodeposition technique of the GOQDs onto the core of a single-mode optical fiber. The nonlinear characterization (NLC) of the GOQDs was carried out using the P-scan technique with a high-gain erbium-doped fiber amplifier (EDFA) at a wavelength of 1550 nm. The obtained results showed a saturable absorption behavior with a value of ß=-1.178x10-6(m/W) and a non-linear susceptibility of Im(χ(3))≈-1.573x10-7(esu). The experimental results of the SA, based on GOQDs as a switching device in a fiber laser, showed a typical behavior of a Q-switched laser by generating a pulsed emission at a wavelength of 1599 nm, a frequency from 2 to 16 kHz, and a maximum average output power of 1.3 mW.

Study of the Scattering Effect by SiO2 Nanoparticles, in a Luminescent Solar Concentrator Sensitized with Carbon Dots.

Luminescent solar concentrators (LSCs) have become an attractive way to produce green energy via their integration into buildings as photovoltaic windows. Recently, carbon quantum dots (C-QDs) have become the most studied luminescent material for the manufacture of luminescent solar concentrators due to their advantages, such as low toxicity, sustainability, and low cost. Despite the advantages of carbon quantum dots, they remain a low-efficiency material, and it is difficult to fabricate LSCs with a good performance. To address this problem, some of the research has used SiO2 nanoparticles (Nps) to produce a light-scattering effect that helps to improve the system performance. However, these studies are limited and have not been discussed in detail. In this regard, this research work was designed to evaluate the contribution of the scattering effect in different systems of carbon quantum dots used in a possible luminescent solar concentrator. To carry out this study, C-QDs and SiO2 Nps were synthesized by hydrothermal methods and the Stober method, respectively. We used different concentrations of both materials to fabricate film LSCs (10 × 10 cm2). The results show that the light scattered by the SiO2 Nps has a double contribution, in terms of light redirected towards the edges of the window and as a secondary source of excitation for the C-QDs; thus, an improvement in the performance of the LSC is achieved. The best improvement in photoluminescence is achieved when the films are composed of 20% wt carbon quantum dots and 10% wt SiO2 Nps, reaching a gain of 16% of the intensity of the light incident on the edges of the window with respect to the LSCs where only C-QDs were used.

Flexible genosensors based on polypyrrole and graphene quantum dots for PML/RARα fusion gene detection: A study of acute promyelocytic leukemia in children.

Acute promyelocytic leukemia (APL) in children is associated with a favorable initial prognosis. However, minimal residual disease (MRD) follow-up remains poorly defined, and relapse cases are concerning due to their recurrent nature. Thus, we report two electrochemical flexible genosensors based on polypyrrole (PPy) and graphene quantum dots (GQDs) for label-free PML-RARα oncogene detection. Atomic force microscopy (AFM), scanning electron microscope (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used to characterize the technological biosensor development. M7 and APLB oligonucleotide sequences were used as bioreceptors to detect oncogenic segments on chromosomes 15 and 17, respectively. AFM characterization revealed heterogeneous topographical surfaces with maximum height peaks for sensor layers when tested with positive patient samples. APLB/Genosensor exhibited a percentage change in anode peak current (ΔI) of 423 %. M7/Genosensor exhibited a ΔI of 61.44 % for more concentrated cDNA samples. The described behavior is associated with the biospecific recognition of the proposed biosensors. Limits of detection (LOD) of 0.214 pM and 0.677 pM were obtained for APLB/Genosensor and M7/Genosensor, respectively. The limits of quantification (LOQ) of 0.648 pM and 2.05 pM were estimated for APLB/Genosensor and M7/Genosensor, respectively. The genosensors showed reproducibility with a relative standard deviation of 7.12 % for APLB and 1.18 % for M7 and high repeatability (9.89 % for APLB and 1.51 % for M7). In addition, genetic tools could identify the PML-RARα oncogene in purified samples, plasmids, and clinical specimens from pediatric patients diagnosed with APL with high bioanalytical performance. Therefore, biosensors represent a valuable alternative for the clinical diagnosis of APL and monitoring of MRD with an impact on public health.

Two-photon absorption in colloidal semiconductor nanocrystals: a review.

Large two-photon absorption (2PA) cross-section combined with high emission quantum efficiency and size-tunable bandgap energy has put colloidal semiconductor nanocrystals (NCs) on the vanguard of nonlinear optical materials. After nearly two decades of intense studies on the nonlinear optical response in quantum-confined semiconductors, this is still a vibrant field, as novel nanomaterials are being developed and new applications are being proposed. In this review, we examine the progress of 2PA research in NCs, highlighting the impact of quantum confinement on the magnitude and spectral characteristics of this nonlinear response in semiconductor materials. We show that for NCs with three-dimensional quantum confinement, the so-called quantum dots, 2PA cross-section grows linearly with the nanoparticle volume, following a universal volume scaling. We overview strategies used to gain further control over the nonlinear optical response in these structures by shape and heterostructure engineering and some applications that might take advantage of the series of unique properties of these nanostructures.

One-Pot Synthesis of CdTe/ZnS Quantum Dots and their Physico-Chemical Characterization.

A known property of quantum dots (QDs) is their characteristic luminescence, which would make it possible to detect different types of cancers after being functionalized with some type of biological molecule. For this reason, in the present investigation a methodological analysis of the physicochemical characteristics of the CdTe/ZnS core/shell QDs was carried out, using techniques such as Optical Absorbance Spectroscopy (UV-Vis), Molecular Fluorescence, Fourier Transform Infrared Spectroscopy (FT-IR), Dynamic Light Scattering (DLS), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Zeta Potential that allowed to verify the photoluminescent effectiveness of these semiconductor nanocrystals as an alternative to conventional techniques currently used for the detection of specific cancers smaller than 1 cm. The study consisted of theoretically determining the bandgap energy, the size of the nanocrystals and the molar absorptivity from the wavelength value for the maximum intensity of the excitonic peak. It was also possible to verify the maximum intensity for each sample and thus evaluate its photoluminescent response, as well as it was possible to determine the charge distribution, the hydrodynamic size and the surface composition of each quantum dot. The results obtained correspond to what has been reported in the literature, which makes them good candidates for the detection of cancer in precancerous stages.

Green nanoarchitectonics of carbon quantum dots from Cinchona Pubescens Vahl as targeted and controlled drug cancer nanocarrier.

Carbon quantum dots (CQDs) are a new carbon-based nanomaterial that has attracted tremendous attention due to their excellent fluorescent properties, chemical stability, water solubility, and biocompatibility features. Here, fluorescent CQDs synthesized by a green nanoarchitectonic method using Cinchona Pubescens Vahl extract were evaluated as drug nanocarriers for carboplatin (CBP) delivery. The characterization methods showed CQDs with semispherical shapes and sizes around 5 nm, temperature- and pH-dependent functional groups that interact with the CBP molecule adding specificity to the drug-delivery system. Based on the load efficiency results, it seems that the CQDs can carry almost 100 µg of carboplatin for every 1 mg of CQDs. This is possible due to the self-assembly process that takes place through the interaction between the protonation/deprotonation functional groups of CQDs and the hydrolyzed CBP molecule. Through this process, it is created spherical nanoparticles with an average size of 77.44 nm. The CQDs-CBP nanoparticles release the drug through a diffusion-controlled release mechanism where the acidic media is preferred, and the EPR effect also plays a helpful role. Besides, the viability test shows that the CQDs have almost null cytotoxicity suggesting that they could be used as a promising cancer treatment, improving the efficiency of cell internalization and significantly increasing their drug delivery.

Review: using rolled-up tubes for strain-tuning the optical properties of quantum emitters.

Rolled-up tubes based on released III-V heterostructures have been extensively studied and established as optical resonators in the last two decades. In this review, we discuss how light emitters (quantum wells and quantum dots) are influenced by the inherently asymmetric strain state of these tubes. Therefore, we briefly review whispering gallery mode resonators built from rolled-up III-V heterostructures. The curvature and its influence over the diameter of the rolled-up micro- and nanotubes are discussed, with emphasis on the different possible strain states that can be produced. Experimental techniques that access structural parameters are essential to obtain a complete and correct image of the strain state for the emitters inside the tube wall. In order to unambiguously extract such strain state, we discuss x-ray diffraction results in these systems, providing a much clearer scenario compared to a sole tube diameter analysis, which provides only a first indication of the lattice relaxation in a given tube. Further, the influence of the overall strain lattice state on the band structure is examined via numerical calculations. Finally, experimental results for the wavelength shift of emissions due to the tube strain state are presented and compared with theoretical calculations available in literature, showing that the possibility to use rolled-up tubes to permanently strain engineer the optical properties of build-in emitters is a consistent method to induce the appearance of electronic states unachievable by direct growth methods.