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1.
Small ; : e2405531, 2024 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-39148199

RESUMEN

Nanotizing biosealant components offer a multitude of chemical functionalities for superior adhesion-cohesion, delivering unique properties for comprehensive wound healing that are otherwise impossible to achieve using commercial variants. For the first time, a two-step controlled hydrothermal pyrolysis is reported to nanotize dopamine, phloroglucinol, and glutaraldehyde into carbon dot (CD) to be subsequently converted into carbonized polymer dot (CPD) with gelatin as a co-substrate. Chemical crosslinking of CD with gelatin through Schiff base formation before the second pyrolysis step ensures a complex yet porous polymeric network. The retention of chemical functionalities indigenous to CD substrates and gelatin along with the preservation of CD photoluminescence in CPD for optical tracking is achieved. A unique nanoformulation is created with the CPD through tannic acid (TA) grafting evolving CPD-TA nanoglue demonstrating ≈1.32 MPa strength in lap shear tests conducted on porcine skin, surpassing traditional bioadhesives. CPD-TA nanoglue uploaded insulin as chosen cargo disbursal at the wound site for healing normal and in vitro diabetic wound models using HEKa cells with extraordinary biocompatibility. Most importantly, CPD-TA can generate reactive oxygen species (ROS) and scavenge simultaneously under ambient conditions (23 W white LED or dark) for on-demand sterilization or aiding wound recovery through ROS scavenging.

2.
Biomacromolecules ; 25(5): 3178-3189, 2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38632677

RESUMEN

Bioadhesives with all-inclusive properties for simultaneous strong and robust adhesion, cohesion, tracking, drug delivery, self-sterilization, and nontoxicity are still farfetched. Herein, a carbon dot (CD) is made to infuse each of the above-desired aspects with gelatin, an inexpensive edible protein. The CD derived through controlled hydrothermal pyrolysis of dopamine and terephthaldehyde retained -NH2, -OH, -COOH, and, most importantly, -CHO functionality on the CD surface for efficient skin adhesion and cross-linking. Facile fabrication of CD-gelatin bioadhesive through covalent conjugation of -CHO of the CD with -NH2 of gelatin through Schiff base formation was accomplished. This imparts remarkable self-healing attributes as well as excellent adhesion and cohesion evident from physicomechanical analysis in a porcine skin model. Improved porosity of the bioadhesive allows loading hemin as a model drug whose disembarkment is tracked with intrinsic CD photoluminescence. In a significant achievement, antibiotic-free self-sterilization of bioadhesive is demonstrated through visible light (white LED, 23 W)-irradiated photosensitization of the CD to produce reactive oxygen species for annihilation of both Gram-positive and Gram-negative bacteria with exceptional efficacy (99.9%). Thus, a comprehensive CD-gelatin bioadhesive for superficial and localized wound management is reported as a promising step for the transformation of the bioadhesive domain through controlled nanotization for futuristic clinical translations.


Asunto(s)
Carbono , Sistemas de Liberación de Medicamentos , Gelatina , Gelatina/química , Carbono/química , Animales , Porcinos , Sistemas de Liberación de Medicamentos/métodos , Esterilización/métodos , Adhesivos Tisulares/química , Adhesivos Tisulares/farmacología , Piel/metabolismo , Piel/efectos de los fármacos
3.
Soft Matter ; 20(2): 449, 2024 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-38099476

RESUMEN

Correction for 'A biomass-derived dual crosslinked DNA-nanoparticle hydrogel for visible light-induced photodynamic bacterial inactivation' by Gourab Das et al., Soft Matter, 2023, https://doi.org/10.1039/D3SM01400B.

4.
Soft Matter ; 19(48): 9511-9519, 2023 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-38047904

RESUMEN

Sustainability in developing novel nanomaterials (NPs) from biomass sources is a challenging proposition mainly due to the difficulty of infusing or retaining desired chemical functionalities in the biomass substrate. In this study, we demonstrate the synthesis of DNA-nanoparticles (DNA-NP) from onion genomic DNA as a plant biomass source through controlled hydrothermal pyrolysis to retain functional groups in the NPs for predictable downstream chemical transformations. A dual crosslinking scheme was introduced that involves the DNA-NP to form a hydrogel. Chemical crosslinking was achieved through the formation of a Schiff base between the -CHO groups of glutaraldehyde and the amine functionality present on the DNA-NP surface as well as in the nucleobases of the dangling DNA strands of DNA-NP. Simultaneous physical entanglement was attained through hybridization-mediated self-assembly of the dangling DNA strands of the DNA-NP with untransformed onion genomic DNA. As a corollary of the dual crosslinking, the resulting hydrogel not only displayed remarkable mechanical strength but also showed self-healing properties. The ability of the DNA-NP to generate reactive oxygen species (ROS) with visible light irradiation is translated to the hydrogel, making the system potent for biofilm destruction. The high loading efficiency of the model drug ampicillin sodium (Amp) in the hydrogel was achieved which was released in four days. This hints towards the application of the hydrogel through combination antibiotic-antibacterial photodynamic treatment (APDT) as demonstrated here with both Gram-positive and Gram-negative bacteria.


Asunto(s)
Hidrogeles , Nanopartículas , Hidrogeles/química , Antibacterianos/química , Biomasa , Bacterias Gramnegativas , Bacterias Grampositivas , Nanopartículas/química , ADN , Luz
5.
Phys Chem Chem Phys ; 25(35): 23645-23657, 2023 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-37609834

RESUMEN

The mechanism of intrinsic fluorescence of carbon dots (CDs), the latest nanomaterial from the carbon family, was supposedly deciphered through multiple theories. However, the much sought-after persistent red emission of CDs as a foreseeable consequence of experiments remains elusive prompting the question of whether tuning of the red emission of CDs is a predictable outcome or a serendipitous coincidence. Herein, we tried to decode the same by exploring Alizarin Red S (ARS)-based red emitting CDs in different solvents with wisely chosen analytical tools. The findings are aptly supported by molecular dynamics studies through an experimental intuition-driven model-building approach. Parallel interception of the CDs with powder X-ray diffraction (pXRD) and photophysical spectroscopic studies revealed an important relationship between the solvent and CDs. Tautomerism, a well-known phenomenon with chemical entities, was found to be operative for CDs that greatly influence the Stokes shift and ultimately the fluorescence outcome. Most importantly, pXRD studies established the turbostratism of the CDs where the well-ordered graphitic structure of CDs gets disrupted with solvent molecules. The extent of such disruption is a function of solvent and CD composition that plays a formidable role in obtaining red fluorescence. Thus, for the first time, we demonstrate that the red emission of CDs is related to its structural integrity and if taken care of could be sustained, a tremendously desirable outcome for relevant applications.

6.
J Agric Food Chem ; 71(34): 12849-12858, 2023 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-37584518

RESUMEN

Economically viable remote sensing of foodborne contaminants using minimalistic chemical reagents and simultaneous automation calls for a concrete integration of a chemical detection strategy with artificial intelligence. In a first of its kind, we report the ultrasensitive detection of citrinin and associated mycotoxins like aflatoxin B1 and ochratoxin A using an Alizarin Red S (ARS) and cystamine-derived carbon dot (CD) that aptly amalgamate with machine learning algorithms for automation. The photoluminescence response of the CD as a function of various solvents and pH is used to generate array channels that are further modulated in the presence of the mycotoxins whose digital images were acquired to determine pixelation, essentially creating a barcode. The barcode was fed to machine learning algorithms that actualize and intertwine convoluted databases, demonstrating Extreme Gradient Boosting (XGBoost) as the optimized model out of eight algorithms tested. Spiked samples of wheat, rice, gram, maize, coffee, and milk were used to evaluate the testing model where an exemplary accuracy of 100% even at 10 pmol of mycotoxin concentration was achieved. Most importantly, the coexistence of mycotoxins could also be detected through the CD array and XGBoost synergy hinting toward a broader scope of the developed methodology for smart detection of foodborne contaminants.


Asunto(s)
Citrinina , Micotoxinas , Micotoxinas/análisis , Citrinina/análisis , Carbono , Inteligencia Artificial , Aflatoxina B1 , Aprendizaje Automático , Contaminación de Alimentos/análisis
7.
Chem Commun (Camb) ; 59(55): 8548-8551, 2023 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-37337886

RESUMEN

A super hydrophobic composite is developed for the first time through the non-covalent self-assembly of a hydrophilic covalent organic framework (COF) and amphoteric CDs to achieve highly selective separation of dispersed micro droplets of oil from an oil/water mixture.


Asunto(s)
Estructuras Metalorgánicas , Contaminación por Petróleo , Carbono , Emulsiones/química , Aceites/química , Interacciones Hidrofóbicas e Hidrofílicas
8.
ACS Appl Bio Mater ; 6(4): 1556-1565, 2023 04 17.
Artículo en Inglés | MEDLINE | ID: mdl-36897091

RESUMEN

Conversion of biomass into nanoparticles for meaningful biomedical applications is a formidable proposition with excellent prospects but fewer patrons. A lack of general methodology for upscaled production and limited versatility of those nanoparticles are the main drawbacks. Herein, we report the creation of a DNA nanoparticle (DNA Dots) from onion genomic DNA (gDNA), a plant biomass source, through controlled hydrothermal pyrolysis in water without any chemicals. The DNA Dots are further formulated into a stimuli-responsive hydrogel through hybridization-mediated self-assembly with untransformed precursor gDNA. The versatility of the DNA Dots is recognized through its crosslinking ability with gDNA through its dangling DNA strands on the surface resulting from incomplete carbonization during annealing without the need for any external organic, inorganic, or polymeric crosslinkers. The gDNA-DNA Dots hybrid hydrogel is shown to be an excellent drug delivery vehicle for sustained release trackable through the inherent fluorescence of the DNA Dots. Interestingly, the DNA Dots are photoexcited with normal visible light to generate on-demand reactive oxygen species, making them exciting candidates for combination therapeutics. Most importantly, the ease with which the hydrogel is internalized in fibroblast cells with minimal cytotoxicity should encourage the nanotization of biomass as a tool for interesting sustainable biomedical applications.


Asunto(s)
Hidrogeles , Nanopartículas , Biomasa , Sistemas de Liberación de Medicamentos/métodos , ADN
9.
J Mater Chem B ; 11(3): 594-605, 2023 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-36533540

RESUMEN

Chemically induced crosslinked enhanced emission (CEE) of urea and citric acid-derived carbon polymer dot (CPD) nanoparticles is established here with a rare zero linker approach, i.e. without the use of any separate crosslinkers. Such chemical CEE like any chemical reaction was achieved through amide bond formation using carbodiimide chemistry, pointing towards the feasibility of developing a general methodology for their formation through engineering the nanoparticle surface functionality. Exhaustive characterization was done to pinpoint the structure, morphology, and photophysics of the CPDs and concurrently eliminate the possibility of the involvement and interference by molecular fluorophores for the unique optical tuning of the CPDs. The structure-photophysics relation was further restated through theoretical studies involving density functional theory (DFT) that correlated significantly well with the experimental findings. Most interestingly, the CPDs revealed pH responsiveness due to the formation or hydrolysis of amide bonds with acid or base, respectively, which was manifested through a spectacular change in fluorescence emission visible to the naked eye through UV illumination. This distinct pH-dependent photoluminescence properties of CPDs opens up an enormous opportunity for interesting applications, including discriminating normal and cancerous cells, which we demonstrate herein as a proof of concept through in vitro imaging.


Asunto(s)
Neoplasias , Polímeros , Polímeros/química , Carbono/química , Fluorescencia , Colorantes Fluorescentes/química , Concentración de Iones de Hidrógeno , Neoplasias/diagnóstico por imagen
10.
Nanoscale ; 14(43): 16097-16109, 2022 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-36226636

RESUMEN

Nanotization of biomass for interesting biomedical applications is still in the nascent stage with no visible market available products. While products derived from biomass DNA and protein have unquestionable biocompatibility, induction of desired properties needs careful manipulation of the biomolecules. Herein, for the first time, we report the transformation of onion derived biomass DNA into DNA-dots through its partial hydrothermal pyrolysis to induce improved mechanical and photophysical properties. The DNA-dots were further used as crosslinkers to create a hydrogel through hybridization-mediated self-assembly with untransformed genomic DNA. The DNA dot-DNA hydrogel sustainably delivers the ciprofloxacin antibiotic as well as produces on-demand reactive oxygen species (ROS) with visible light irradiation. This prompted us to explore the hydrogel as a topical formulation for combination antibiotic Antibacterial-Photodynamic Therapy (APDT) applications. Remarkable annihilation of E. coli and S. aureus, and most importantly two drug-resistant strains of E. coli, shows the success of our sustainable approach.


Asunto(s)
Hidrogeles , Staphylococcus aureus , Hidrogeles/farmacología , Escherichia coli , Biomasa , Antibacterianos/farmacología , ADN
11.
Sci Rep ; 12(1): 16453, 2022 09 30.
Artículo en Inglés | MEDLINE | ID: mdl-36180490

RESUMEN

We evaluated the anti-leishmanial efficacy of different saturated medium-chain fatty acids (FAs, C8-C18) where FA containing C8 chain, caprylic acid (CA), was found to be most potent against Leishmania donovani, the causative agent for visceral leishmaniasis (VL). Different analogs of CA with C8 linear chain, but not higher, along with a carboxyl/ester group showed a similar anti-leishmanial effect. Ergosterol depletion was the major cause of CA-mediated cell death. Molecular docking and molecular dynamic simulation studies indicated the enzyme mevalonate kinase (MevK) of the ergosterol biosynthesis pathway as a possible target of CA. Enzyme assays with purified recombinant MevK and CA/CA analogs confirmed the target with a competitive inhibition pattern. Using biochemical and biophysical studies; strong binding interaction between MevK and CA/CA analogs was established. Further, using parasites with overexpressed MevK and proteomics studies of CA-treated parasites the direct role of MevK as the target was validated. We established the mechanism of the antileishmanial effect of CA, a natural product, against VL where toxicity and drug resistance with current chemotherapeutics demand an alternative. This is the first report on the identification of an enzymatic target with kinetic parameters and mechanistic insights against any organism for a natural medium-chain FA.


Asunto(s)
Antiprotozoarios , Productos Biológicos , Leishmania donovani , Leishmaniasis Visceral , Antiprotozoarios/uso terapéutico , Productos Biológicos/farmacología , Caprilatos/farmacología , Ergosterol/metabolismo , Ésteres/farmacología , Ácidos Grasos/metabolismo , Humanos , Leishmaniasis Visceral/parasitología , Simulación del Acoplamiento Molecular , Fosfotransferasas (Aceptor de Grupo Alcohol)
12.
ACS Omega ; 6(33): 21425-21435, 2021 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-34471745

RESUMEN

The use of carbon quantum dots (CDs) as trackable nanocarriers for plasmid and gene as hybrid DNA condensates has gained momentum, as evident from the significant recent research efforts. However, the in-depth morphology of the condensates, the energetics of the condensation process, and the photophysical aspects of the CD are not well understood and often disregarded. Herein, for the first time, we covalently attached linearized pUC19 with citric acid and cysteamine-derived CD through the reaction of the surface amine groups of CDs with the 5'-phospho-methyl imidazolide derivative of the plasmid to obtain a 1:1 CD-pUC19 covalent conjugate. The CD-pUC19 conjugates were further transformed into DNA condensates with spermine that displayed a toroidal morphology with a diameter of ∼200 nm involving ∼2-5 CD-pUC19 conjugates in a single condensate. While the interaction of pristine CD to spermine was exothermic, the binding of the CD-pUC19 conjugate with spermine was endothermic and primarily entropy-driven. The condensed plasmid displayed severe conformational stress and deviation from the B-form due to the compact packing of the DNA but better transfection ability than the pristine CD. The CDs in the condensates tend to come close to each other at the core that results in their shielding from excitation. However, this does not prevent them from emanating reactive oxygen species on visible light exposure that compromises the decondensation process and cell viability at higher exposure times, calling for utmost caution in establishing them as nonviral transfecting agents universally.

13.
Nanoscale ; 13(33): 14147-14155, 2021 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-34477696

RESUMEN

The potential of carbon dots (CDs) for photonic conversion to charged states, together with the ability of DNA to transport such charge for extensive charge separation, offers an opportunity to control directionality of migration for photo-induced radical cations in CD-DNA based nano-assemblies. This is achieved through engineering the reaction valency of CDs whereby one CD is covalently conjugated with one ssDNA strand. Subsequently, a CD-DNA-CD nano-dumbbell architecture was created through hybridization mediated self-assembly. The time and intensity-dependent transduction of visible light photonic energy to chemical potential in DNA was achieved through irradiation of 1,4-diaminoathraquinone and glyoxal derived CD with 100 W tungsten source and natural sunlight. Following charge injection by CD, the radical cation migration in DNA was perceived through trapping of the hole in repeated GG steps in the DNA. Overall, a breakthrough in visible-light-induced charge transfer by CD into DNA was achieved, potentially applicable to optobioelectronics.


Asunto(s)
Carbono , Puntos Cuánticos , ADN , Luz , Hibridación de Ácido Nucleico
14.
Nanomedicine (Lond) ; 16(21): 1887-1903, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34397295

RESUMEN

Aim: To analyze the efficacy and possible mechanism of action of 7,8-dihydroxyflavone (DHF) and DHF synthesized gold nanoparticles (GNPs) against the parasite Leishmania donovani. Methods: GNPs were synthesized using DHF and characterized by dynamic light scattering, ζ potential, Fourier transform infrared spectroscopy, transmission electron microscopy and x-ray diffraction. The efficacy of DHF and DHF-GNP were tested against sensitive and drug-resistant parasites. GNP uptake was measured on macrophages by atomic absorption spectroscopy. Results: DHF and DHF-GNP (∼35 nm) were equally effective against sensitive and drug-resistant strains and inhibited the arginase activity of parasites. Increased IFN-γ and reduced IL-12 cytokine response showed a Th1/Th2-mediated cell death in macrophages. Conclusion: The low cytotoxicity and high biological activity of DHF-GNP may be useful for chemotherapy of leishmaniasis.


Asunto(s)
Leishmania donovani , Nanopartículas del Metal , Arginasa , Flavonas , Oro
15.
Chem Biol Drug Des ; 97(6): 1170-1184, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33764683

RESUMEN

DNA alkylation damage, emanating from the exposure to environmental alkylating agents or produced by certain endogenous metabolic processes, affects cell viability and genomic stability. Fe(II)/2-oxoglutarate-dependent dioxygenase enzymes, such as Escherichia coli AlkB, are involved in protecting DNA from alkylation damage. Inspired by the natural product indenone derivatives reported to inhibit this class of enzymes, and a set of 2-chloro-3-amino indenone derivatives was synthesized and screened for their inhibitory properties against AlkB. The synthesis of 2-chloro-3-amino indenone derivatives was achieved from 2,3-dichloro indenones through addition-elimination method using alkyl/aryl amines under catalyst-free conditions. Using an in vitro reconstituted DNA repair assay, we have identified a 2-chloro-3-amino indenone compound 3o to be an inhibitor of AlkB. We have determined the binding affinity, mode of interaction, and kinetic parameters of inhibition of 3o and tested its ability to sensitize cells to methyl methanesulfonate that mainly produce DNA alkylation damage. This study established the potential of indenone-derived compounds as inhibitors of Fe(II)/2-oxoglutarate-dependent dioxygenase AlkB.


Asunto(s)
Alquilantes/síntesis química , Reparación del ADN , Indenos/química , Alquilantes/farmacología , Sitios de Unión , Daño del ADN , Desmetilación del ADN/efectos de los fármacos , Reparación del ADN/efectos de los fármacos , Escherichia coli/enzimología , Proteínas de Escherichia coli/antagonistas & inhibidores , Proteínas de Escherichia coli/metabolismo , Humanos , Indenos/metabolismo , Indenos/farmacología , Cinética , Oxigenasas de Función Mixta/antagonistas & inhibidores , Oxigenasas de Función Mixta/metabolismo , Simulación del Acoplamiento Molecular , Unión Proteica
16.
Parasitol Int ; 82: 102287, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33515743

RESUMEN

The global prevalence of HIV is a major challenge for the control of visceral leishmaniasis. Although the effectiveness and usefulness of amprenavir (APV) are well studied in anti-retroviral regimens, very little is known on HIV/VL-co-infected patients. In the present study, we report for the first time the protective efficacy of APV against visceral leishmaniasis by inhibition of DNA Topoisomerase I (LdTOP1LS) and APV-induced downstream pathway in programmed cell death (PCD). During the early phase of activation, reactive oxygen species (ROS) is increased inside the cells, which causes subsequent elevation of lipid peroxidation. Endogenous ROS formation and lipid peroxidation cause eventual depolarization of mitochondrial membrane potential (ΔΨm). Furthermore, the release of cytochrome c and activation of CED3/CPP32 group of proteases lead to the formation of oxidative DNA lesions followed by DNA fragmentation. The promising in vitro and ex vivo results promoted to substantiate further by in vivo animal experiment, which showed a significant reduction of splenic and hepatic parasites burden compared to infected controls. Interestingly, APV selectively targets LdTOPILS and does not inhibit the catalytic activity of human topoisomerase I (hTopI). Moreover, based on the cytotoxicity test APV is not toxic for host macrophage cells, which is correlated with non-responsiveness of inhibition of catalytic activity of hTopI. Taken together, this study provides the opportunity for discovering and evaluating newer potential molecular therapeutic targets for drug designing. The present study might be exploited in future as important therapeutics, which will be useful for treatment of VL as well as HIV-VL co-infection.


Asunto(s)
Antiprotozoarios/farmacología , Carbamatos/farmacología , ADN-Topoisomerasas de Tipo I/metabolismo , Furanos/farmacología , Leishmania donovani/efectos de los fármacos , Proteínas Protozoarias/metabolismo , Sulfonamidas/farmacología , Apoptosis , Inhibidores de la Proteasa del VIH/farmacología , Leishmania donovani/enzimología , Estrés Oxidativo
17.
J Hazard Mater ; 392: 122287, 2020 06 15.
Artículo en Inglés | MEDLINE | ID: mdl-32066019

RESUMEN

The creation of a polymeric hydrogel from polyvinylpyrrolidone (PVP) cross-linked by Carbon Quantum Dots (CD) for the adsorption and photocatalytic degradation of both cationic and anionic dyes. PVP, an important biocompatible constituent and often surplus in cosmetic industry, was carboxylated through NaOH refluxing and covalently conjugated to surface amine functionality of CD derived from lemon juice and Cysteamine. The hybrid hydrogel was obtained from PVP-CD covalent conjugate by careful manipulation of pH and found to possess better rheological properties than only carboxylate-PVP. The monolayer physisorption of the dyes on the hydrogel was affected by hydrogen bonding, dispersion or inductive effect, and π-π interaction with the polymer backbone as well as the CD that followed pseudo-second-order kinetics. Degradation of the adsorbed dyes was instated by the unique Reactive Oxygen Species (ROS) generating ability of the CD embedded in the hydrogel matrix upon exposure to sunlight, the mechanism of which is also unveiled. The same CD-induced ROS was found to effectively annihilate both gram-positive and gram-negative bacteria in real polluted water in less than 10 min of photoexcitation of the hydrogel. The hydrogel was restored by mild acid wash that is able to perform dye adsorption and photo-degradation upto four cycles.


Asunto(s)
Carbono , Hidrogeles , Povidona , Puntos Cuánticos , Purificación del Agua/métodos , Carbono/administración & dosificación , Carbono/química , Carbono/efectos de la radiación , Colorantes/química , Escherichia coli/efectos de los fármacos , Escherichia coli/crecimiento & desarrollo , Hidrogeles/administración & dosificación , Hidrogeles/química , Hidrogeles/efectos de la radiación , Fotólisis , Povidona/administración & dosificación , Povidona/química , Povidona/efectos de la radiación , Puntos Cuánticos/administración & dosificación , Puntos Cuánticos/química , Puntos Cuánticos/efectos de la radiación , Especies Reactivas de Oxígeno/química , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/crecimiento & desarrollo , Luz Solar , Aguas Residuales , Contaminantes del Agua/química
18.
Food Chem ; 312: 126076, 2020 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-31896461

RESUMEN

Ultrasensitive visual detection of mycotoxin citrinin is reported here using a novel yellow-light emitting Carbon dot (CD) and Congo red dye. Detection strategy is based on higher binding affinity of citrinin with diammonium citrate, and urea derived CD over Congo red in presence of Mg2+. Congo red statically quenched the yellow fluorescence of CD, resulting in emission in red region, which was restored in presence of citrinin. Visual limit of detection (LOD) of 10 pmol and spectroscopic LOD of 6.6 pmol/mL was achieved within 5 min of incubation with citrinin. The assembly was found to respond well for citrinin detection in the presence of Aflatoxin b1 (AFL b1) and Ochratoxin A (OTA), that frequently co-exist with citrinin in real food samples. The method exhibits immense potential to sense citrinin in sub-nanogram range by visual inspection in an inexpensive yet robust on-site detection platform in relevant food packaging and agricultural industry.


Asunto(s)
Citrinina/análisis , Aflatoxina B1/química , Carbono , Rojo Congo , Límite de Detección , Ocratoxinas/química
19.
Org Lett ; 22(4): 1605-1610, 2020 02 21.
Artículo en Inglés | MEDLINE | ID: mdl-31990569

RESUMEN

We report here a direct and efficient strategy for the synthesis of highly conjugated dimeric pyrrolo-fused isoquinoline derivatives from readily available benzamides and maleimides. This reaction overall proceeds by following a domino approach: C-C bond formation via challenging primary amide-directed Ru(II)-catalyzed ortho alkenylation followed by annulation and C-C bond formation through Ru(II)-catalyzed dehydrogenative dimerization. The resulting products showed substituent-dependent tunable photoluminescence in the orange-red region with reasonably large Stokes shifts and interesting redox properties.

20.
ACS Appl Bio Mater ; 3(11): 7865-7875, 2020 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-35019527

RESUMEN

A two-step methodology for simultaneous conjugation of DNA and poly(vinylpyrrolidone) (PVP) polymer to a single carbon quantum dot (CD) is demonstrated for the first time to fabricate a pH-responsive DNA-CD-PVP hybrid hydrogel. Cross-linking in the hydrogel was achieved using CD as the common nucleus through the formation of DNA I-motif conformation at neutral to acidic pH and noncovalent interaction of PVP that infuse self-healing and shape memory properties in the hydrogel. The hydrogel is capable of loading and sustained delivery of drugs for more than 2 weeks as demonstrated using a model drug, Hemin. The quenching of fluorescence of CD by Hemin was trackable even through simple visual monitoring, which showed that Hemin can diffuse from the loaded part to the unloaded part of the hydrogel during the self-healing process. Most significantly, the chosen CD generates reactive oxygen species (ROS) upon visible light irradiation, armoring the hydrogel with worthy antimicrobial activity. Biocompatibility of the DNA-CD-PVP hydrogel was established on human fibroblast cells, indicating their potential use in biomedical area pertaining to wound healing.

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