RESUMEN
Gold nanoclusters (AuNCs) are an intensely pursued class of fluorophores with excellent biocompatibility, high water solubility, and ease of further conjugation. However, their low quantum yield limits their applications, such as ultra-sensitive chemical or molecular sensing. To address this problem, various strategies have been adopted for augmenting their fluorescence intensity. Herein, we report a facile and scalable approach for the fluorescence enhancement of bovine serum albumin (BSA) capped AuNCs (BSA-AuNCs) using periodic, close-packed polystyrene colloidal photonic crystals (CPCs). The slow photon effect at the bandgap edges is utilized for the increased light-matter interactions and thereby enhancing the fluorescence intensity of the BSA-AuNCs. Compared to the planar polystyrene control sample, the CPC film yielded a 14-fold enhancement in fluorescence intensity. Further, we demonstrated the as-prepared BSA-AuNCs-CPC as a solid-state platform for the highly sensitive and selective fluorescence turn-off detection of creatinine at nanomolar level.
Asunto(s)
Creatinina , Colorantes Fluorescentes , Nanopartículas del Metal , Creatinina/química , Fluorescencia , Colorantes Fluorescentes/química , Oro/química , Nanopartículas del Metal/química , Poliestirenos , Albúmina Sérica Bovina/química , Espectrometría de FluorescenciaRESUMEN
BACKGROUND: Breastfeeding provides perfect nutrition for infants. The inverted nipples in mothers make breastfeeding more challenging. Besides surgical approaches, non-pharmacological interventions are also gaining importance. RESEARCH AIM: To evaluate the effectiveness of Hoffman's exercise on breastfeeding among postnatal mothers with grade I inverted nipples. METHOD: A quantitative approach with a parallel arm randomized controlled trial was used in the study. Postnatal mothers were screened for inverted nipples using a pinch test. Participants with at least one inverted nipple (Grade 1) were randomly allocated into two groups: the experimental group (supported with Hoffman's exercise; n = 28, 50.9% ) and the control group (without Hoffman's exercise; n = 27, 49.1%). The pre-test data, including demographics, nipple length, and breastfeeding assessment, were collected. Breastfeeding assessment was evaluated using the Bristol Breastfeeding Assessment Tool (BBAT). On the 3rd day, the post-test data, including nipple length and Breastfeeding Assessment, were collected among the groups. RESULTS: The BBAT assessment was significantly higher in the post-test compared to that of the pre-test in the participants provided with Hoffman's exercise. The nipple length was found to be higher in participants provided with Hoffman's exercise. Furthermore, the variables-including age, gravida, nipple problems, and delivery type-were not found to have any significant effect with either pre-test or post-test levels of breastfeeding. CONCLUSIONS: Hoffman's exercise was found to be an effective method to improve breastfeeding in Grade 1 nipple-inverted among post-natal mothers. This nipple exercise is inexpensive, easy to follow, and results in the successful initiation of breastfeeding. CLINICAL TRIAL REGISTRY AND REGISTRATION NUMBER: CTRI/2019/05/019279, May 23, 2019 (retrospectively registered).
Asunto(s)
Lactancia Materna , Pezones , Femenino , Lactante , Humanos , Madres , Ejercicio Físico , Proyectos de InvestigaciónRESUMEN
[This corrects the article DOI: 10.1021/acsomega.0c00410.].
RESUMEN
Development of selective, ultra-sensitive, rapid and facile methods for the detection of chemical residues of toxic pesticides and hazardous chemicals are quite important in food safety, environmental monitoring and safeguarding public health. Herein, we presented a fluorescent turn-on aptasensor based on sulphur-doped graphene quantum dot (S-GQD) utilizing specific recognition and binding property of aptamer for the ultra-sensitive and selective detection of omethoate (OM) which is a systemic organophosphorus pesticide. The detection method is based on tuning aggregation-disaggregation mechanism of S-GQD by way of conformational alteration of the recognition probe. Fluorescence 'turn-on' process includes aggregation-induced quenching of S-GQD with aptamer via S-GQD-aptamer complex formation and its subsequent fluorescence recovery with the addition of OM by structural switching of S-GQD-aptamer complex to aptamer-omethoate complex. The reported 'switch-on' aptasensor has exhibited a low limit of detection of 0.001 ppm with high selectivity for OM over other pesticides.
Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Grafito , Plaguicidas , Puntos Cuánticos , Dimetoato/análogos & derivados , Límite de Detección , Compuestos Organofosforados , AzufreRESUMEN
Direct visualization of soft organic molecules like cellulose is extremely challenging under a high-energy electron beam. Herein, we adopt two ionization damage extenuation strategies to visualize the lattice arrangements of the ß-(1â4)-d-glucan chains in carboxylated nanocellulose fibers (C-NCFs) having cellulose II crystalline phase using high-resolution transmission electron microscopy. Direct imaging of individual nanocellulose fibrils with high-resolution and least damage under high-energy electron beam is achieved by employing reduced graphene oxide, a conducting material with high electron transmittance and Ag+ ions, with high electron density, eliminating the use of sample-specific, toxic staining agents, or other advanced add-on techniques. Furthermore, the imaging of cellulose lattices in a C-NCF/TiO2 nanohybrid system is accomplished in the presence of Ag+ ions in a medium revealing the mode of association of C-NCFs in the system, which validates the feasibility of the presented strategy. The methods adopted here can provide further understanding of the fine structures of carboxylated nanocellulose fibrils for studying their structure-property relationship for various applications.
RESUMEN
Size and shape controlled synthesis remains a major bottleneck in the research on nanoparticles even after the development of different methods for their preparation. By tuning the size and shape of a nanoparticle, the intrinsic properties of the nanoparticle can be controlled leading tremendous potential applications in different fields of science and technology. We describe a facile route for the one pot synthesis of gold nanoparticles in water using monosodium glutamate as the reducing and stabilizing agent in the absence of seed particles. The particle diameter can be easily controlled by varying the pH of the reaction medium. Nanoparticles were characterized using scanning electron microscopy, UV-vis absorption spectroscopy, cyclic voltammetry, and dynamic light scattering. Zeta potential measurements were made to compare the stability of the different nanoparticles. The results suggest that lower pH favours a nucleation rate giving rise to smaller particles and higher pH favours a growth rate leading to the formation of larger particles. The synthesized nanoparticles are found to be stable and biocompatible. The nanoparticles synthesized at high pH exhibited a good electrocatalytic activity towards oxidation of nicotinamide adenine dinucleotide (NADH).