21 documents found, page 1 of 3
Carbon dots from coffee grounds: synthesis, characterization, and detection of ...
Costa, Alexandra I.; Barata, Patrícia; Moraes, Bianca; Prata, José V.Coffee ground (CG) waste is generated in huge amounts all over the world, constituting a serious environmental issue owing to its low biodegradability. Therefore, processes that simultaneously aim for its valorization while reducing its environmental impact are in great demand. In the current approach, blue luminescent carbon dots (C-dots) were produced in good chemical yields from CGs following hydrothermal ca...
Luminescent carbon dots from wet olive pomace: structural insights, photophysic...
Sousa, Diogo A.; Ferreira, L.F. Vieira; Fedorov, Alexander A.; Rego, Ana; Ferraria, Ana Maria; Cruz, Adriana; Berberan-Santos, Mario; Prata, José V.Carbon nanomaterials endowed with significant luminescence have been synthesized for the first time from an abundant, highly localized waste, the wet pomace (WP), a semi-solid by-product of industrial olive oil production. Synthetic efforts were undertaken to outshine the photoluminescence (PL) of carbon nanoparticles through a systematic search of the best reaction conditions to convert the waste biomass, main...
Carbon dots synthesis from coffee grounds, and sensing of nitroanilines
Moraes, Bianca; Costa, Alexandra I.; Barata, Patrícia; Prata, José V.Fluorescent carbon dots (C-dots) were directly synthesized by a sustainable and eco friendly one-pot microwave-assisted hydrothermal carbonization method from coffee grounds waste. The coffee grounds obtained from automatic coffee machines, after being heated at 190 °C for 1–4 h in the presence of nitrogen additives, furnished the desired carbon nanomaterials. Struc tural and photophysical properties of the as-...
Carbon dots from coffee grounds by a one-pot microwave-assisted method
Moraes, Bianca; Costa, Alexandra I.; Barata, Patrícia; Prata, José V.Carbon-based nanomaterials, particularly carbon dots (C-dots) have attracted the researchers interest due their excellent luminescence, photostability and biocompatibility, encouraging their use in several areas such as biomedicine, (bio)sensors, photocatalysis and optoelectronics. C-dots could be prepared by a variety of methods (top-down and bottom-up approaches), using a great diversity of carbon sources. Bo...
Fluorescent bis-calix[4]arene-carbazole conjugates: synthesis and inclusion com...
Barata, Patrícia; Costa, Alexandra I.; Costa, Sérgio; Prata, José V.Supramolecular chemistry has become a central theme in chemical and biological sciences over the last decades. Supramolecular structures are being increasingly used in biomedical applications, particularly in devices requiring specific stimuli-responsiveness. Fullerenes, and supramolecular assemblies thereof, have gained great visibility in biomedical sciences and engineering. Sensitive and selective methods ar...
Finding value in wastewaters from the cork industry: carbon dots synthesis and ...
Alexandre, Marta R.; Costa, Alexandra I.; Berberan-Santos, Mario; Prata, José V.Valorisation of industrial low-value waste residues was preconized. Hence, carbon dots (C-dots) were synthesized from wastewaters of the cork industry—an abundant and a_ordable, but environmentally-problematic industrial e_uent. The carbon nanomaterials were structurally and morphologically characterised, and their photophysical properties were analysed by an ensemble of spectroscopy techniques. Afterwards, the...
A solid-state fluorescence sensor for nitroaromatics and nitroanilines based on...
Prata, José V.; Costa, Alexandra I.; Teixeira, CarlosA new conjugated polymer possessing calix[4]arene-oxacyclophane units wired-in-series by phenyleneethynylene linkers was synthesized by a Sonogashira-Hagihara cross-coupling method in high yield. The polymer was structurally characterized by FTIR and 1H/13C/HSQC NMR techniques, and its average Mn (38.5 kDa) retrieved from GPC analysis. The polymer is highly emissive (ΦF =0.55) and exhibits a longer-than-usual e...
Highly sensitive and selective fluorescent probes for Cu(II) detection based on...
Costa, Alexandra I.; Barata, Patrícia; Fialho, Carina; Prata, José V.A new topological design of fluorescent probes for sensing copper ion is disclosed. The calix[4]arene-oxacyclophane (Calix-OCP) receptor, either wired-in-series in arylene-alt-ethynylene conjugated polymers or standing alone as a sole molecular probe, display a remarkable a_nity and selectivity for Cu(II). The unique recognition properties of Calix-OCP system toward copper cation stem from its pre-organised cyc...
Polímeros fluorescentes para a detecção de metais tóxicos
Fialho, Carina B.; Barata, Patrícia; Prata, José V.; Costa, Alexandra I.As reconhecidas capacidades dos calixarenos como receptores moleculares sintéticos, capazes de interagir e formar, selectivamente, complexos com espécies moleculares e iónicas, suscitaram o nosso interesse na sua incorporação em sistemas poliméricos conjugados, perspectivando a ocorrência da amplificação do sinal de transdução em processos de detecção de explosivos [1] e biomoléculas [2]. Na presente comunicaçã...
Adsorption of myoglobin on calixarenes and biocatalysis in organic media
Semedo, Magda C.; Karmali, Amin; Barata, Patrícia; Prata, José V.Derivatives of p-tert-butylcalix[4,6,8]arene carboxylic acids were used for selective adsorption of myoglobin.Amixtureofmyoglobin,laccaseandperoxidase wasusedforextractionwithcalixarenesandonlymyoglobin was selectively extracted to organic media. Myoglobin and Mb c–calixarene exhibited pseudoactivity of peroxidase in aqueous and organic media. This protein-calixarene complex exhibited the highest specific activi...