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1.
Molecules ; 26(11)2021 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-34204994

RESUMO

Chlorophylls and bacteriochlorophylls, together with carotenoids, serve, noncovalently bound to specific apoproteins, as principal light-harvesting and energy-transforming pigments in photosynthetic organisms. In recent years, enormous progress has been achieved in the elucidation of structures and functions of light-harvesting (antenna) complexes, photosynthetic reaction centers and even entire photosystems. It is becoming increasingly clear that light-harvesting complexes not only serve to enlarge the absorption cross sections of the respective reaction centers but are vitally important in short- and long-term adaptation of the photosynthetic apparatus and regulation of the energy-transforming processes in response to external and internal conditions. Thus, the wide variety of structural diversity in photosynthetic antenna "designs" becomes conceivable. It is, however, common for LHCs to form trimeric (or multiples thereof) structures. We propose a simple, tentative explanation of the trimer issue, based on the 2D world created by photosynthetic membrane systems.


Assuntos
Cianobactérias/metabolismo , Complexos de Proteínas Captadores de Luz/química , Complexos de Proteínas Captadores de Luz/metabolismo , Plantas/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Transferência de Energia , Modelos Moleculares , Fotossíntese , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Conformação Proteica , Multimerização Proteica
2.
J Phys Chem B ; 125(23): 6255-6263, 2021 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-34081465

RESUMO

In the strive to develop triplet-triplet annihilation photon upconversion (TTA-UC) to become applicable in a viable technology, there is a need to develop upconversion systems that can function well in solid states. One method to achieve efficient solid-state TTA-UC systems is to replace the intermolecular energy-transfer steps with the corresponding intramolecular transfers, thereby minimizing loss channels involved in chromophore diffusion. Herein, we present a study of photon upconversion by TTA internally within a polymeric annihilator network (iTTA). By the design of the annihilator polymer and the choice of experiment conditions, we isolate upconversion emission governed by iTTA within the annihilator particles and eliminate possible external TTA between separate annihilator particles (xTTA). This approach leads to mechanistic insights into the process of iTTA and makes it possible to explore the upconversion kinetics and performance of a polymeric annihilator. In comparison to a monomeric upconversion system that only functions using xTTA, we show that upconversion in a polymeric annihilator is efficient also at extremely low annihilator concentrations and that the overall kinetics is significantly faster. The presented results show that intramolecular photon upconversion is a versatile concept for the development of highly efficient solid-state photon upconversion materials.


Assuntos
Antracenos , Polímeros , Difusão , Transferência de Energia , Fótons
3.
Nat Protoc ; 16(7): 3695-3715, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099942

RESUMO

Super-resolution fluorescence imaging that surpasses the classical optical resolution limit is widely utilized for resolving the spatial organization of biological structures at molecular length scales. In one example, single-molecule localization microscopy, the lateral positions of single molecules can be determined more precisely than the diffraction limit if the camera collects individual photons separately. Using several schemes that introduce engineered optical aberrations in the imaging optics, super-resolution along the optical axis (perpendicular to the sample plane) has been achieved, and single-molecule localization microscopy has been successfully applied for the study of 3D biological structures. Nonetheless, the achievable axial localization accuracy is typically three to five times worse than the lateral localization accuracy. Only a few exceptional methods based on interferometry exist that reach nanometer 3D super-resolution, but they involve enormous technical complexity and restricted sample preparations that inhibit their widespread application. We developed metal-induced energy transfer imaging for localizing fluorophores along the axial direction with nanometer accuracy, using only a conventional fluorescence lifetime imaging microscope. In metal-induced energy transfer, experimentally measured fluorescence lifetime values increase linearly with axial distance in the range of 0-100 nm, making it possible to calculate their axial position using a theoretical model. If graphene is used instead of the metal (graphene-induced energy transfer), the same range of lifetime values occurs over a shorter axial distance (~25 nm), meaning that it is possible to get very accurate axial information at the scale of a membrane bilayer or a molecular complex in a membrane. Here, we provide a step-by-step protocol for metal- and graphene-induced energy transfer imaging in single molecules, supported lipid bilayer and live-cell membranes. Depending on the sample preparation time, the complete duration of the protocol is 1-3 d.


Assuntos
Transferência de Energia , Grafite/química , Metais/química , Nanotecnologia/métodos , Imagem Individual de Molécula/métodos , Animais , Linhagem Celular Tumoral , Sobrevivência Celular , Análise de Dados , Cães , Corantes Fluorescentes/química , Humanos , Imageamento Tridimensional , Células Madin Darby de Rim Canino , Microscopia de Fluorescência , Interface Usuário-Computador
4.
Talanta ; 232: 122409, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34074399

RESUMO

Cadmium contamination is a severe food safety risk for human health. Herein, a long afterglow "off-on" phosphorescent aptasensor was developed based on phosphorescence resonance energy transfer (PRET) for the detection of Cd2+ in complex samples which minimizes the interference of background fluorescence. In this scheme, initially the phosphorescence of Cd2+-binding aptamer conjugated long afterglow nanoparticles (Zn2GeO4:Mn) was quenched by black hole quencher 1 (BHQ1) modified complementary DNA. Upon encountering of Cd2+, the aptamer interacted with Cd2+ and the complementary DNA with BHQ1 was released, leading to phosphorescence recovery. The content of Cd2+ could be quantified by the intensity of phosphorescence recovery with 100 µs gate time (which eliminated the sample autofluorescence) with a linear relationship between 0.5 and 50 µg L-1 and a limit of detection (LOD) of 0.35 µg L-1. This method was successfully demonstrated for Cd2+ detection in drinking water and yesso scallop samples. The "off-on" phosphorescent aptasensor based on PRET of long afterglow nanomaterials could be an effective tool for Cd2+ detection in food samples.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Cádmio , Transferência de Energia , Humanos , Limite de Detecção
5.
Nat Commun ; 12(1): 3284, 2021 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-34078890

RESUMO

Vibrational energy transfer (VET) is essential for protein function. It is responsible for efficient energy dissipation in reaction sites, and has been linked to pathways of allosteric communication. While it is understood that VET occurs via backbone as well as via non-covalent contacts, little is known about the competition of these two transport channels, which determines the VET pathways. To tackle this problem, we equipped the ß-hairpin fold of a tryptophan zipper with pairs of non-canonical amino acids, one serving as a VET injector and one as a VET sensor in a femtosecond pump probe experiment. Accompanying extensive non-equilibrium molecular dynamics simulations combined with a master equation analysis unravel the VET pathways. Our joint experimental/computational endeavor reveals the efficiency of backbone vs. contact transport, showing that even if cutting short backbone stretches of only 3 to 4 amino acids in a protein, hydrogen bonds are the dominant VET pathway.


Assuntos
Alanina/análogos & derivados , Proteínas/química , Triptofano/química , Regulação Alostérica , Azulenos/química , Transferência de Energia , Ligação de Hidrogênio , Simulação de Dinâmica Molecular , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Teoria Quântica , Soluções , Termodinâmica , Vibração
6.
Analyst ; 146(13): 4254-4260, 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34100481

RESUMO

In this work, a novel electrochemiluminescence (ECL) aptasensor based on the resonance energy transfer (RET) effect between Ag3PO4-Cu-MOF (ii) and silver nanoparticles (Ag NPs) is proposed. The ECL emission spectra of Ag3PO4-Cu-MOF and the ultraviolet absorption spectra of Ag NPs showed a good spectral overlap. Based on this, we designed an "on-off-on" ECL sensing strategy for the sensitive and specific detection of diethylstilbestrol (DES). Under the optimal conditions, the linear range of the sensor for DES detection was 1.0 × 10-12-1.0 × 10-4 M, with a detection limit of 7.2 × 10-13 M (S/N = 3). The method showed simple and fast operation, high sensitivity and selectivity, a strong anti-interference ability and good stability. More importantly, the developed aptasensor exhibited excellent recognition towards residual DES in actual water samples. The sensor has superior measurement capability and potential application value in the field of environment water quality monitoring.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Dietilestilbestrol , Técnicas Eletroquímicas , Transferência de Energia , Limite de Detecção , Medições Luminescentes , Prata
7.
J Phys Chem Lett ; 12(23): 5448-5455, 2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34081477

RESUMO

Reaction centers (RCs) are the pivotal component of natural photosystems, converting solar energy into the potential difference between separated electrons and holes that is used to power much of biology. RCs from anoxygenic purple photosynthetic bacteria such as Rhodobacter sphaeroides only weakly absorb much of the visible region of the solar spectrum, which limits their overall light-harvesting capacity. For in vitro applications such as biohybrid photodevices, this deficiency can be addressed by effectively coupling RCs with synthetic light-harvesting materials. Here, we studied the time scale and efficiency of Förster resonance energy transfer (FRET) in a nanoconjugate assembled from a synthetic quantum dot (QD) antenna and a tailored RC engineered to be fluorescent. Time-correlated single-photon counting spectroscopy of biohybrid conjugates enabled the direct determination of FRET from QDs to attached RCs on a time scale of 26.6 ± 0.1 ns and with a high efficiency of 0.75 ± 0.01.


Assuntos
Transferência de Energia , Transferência Ressonante de Energia de Fluorescência/métodos , Nanoconjugados/química , Complexo de Proteínas do Centro de Reação Fotossintética/química , Proteobactérias/química , Pontos Quânticos/química , Nanoconjugados/análise , Fotossíntese , Complexo de Proteínas do Centro de Reação Fotossintética/análise , Pontos Quânticos/análise , Rhodobacter sphaeroides/química , Energia Solar
8.
Methods Mol Biol ; 2274: 103-110, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34050466

RESUMO

Coelenterazine (CTZ) is the most general substrate for marine luciferases. The present protocol introduces a near-infrared (NIR ) bioluminescence (BL) imaging of mammalian cells with a cyanine-5 (Cy5) dye-conjugated CTZ . This unique Cy5-conjugated CTZ, named Cy5-CTZ , can act as a dual optical readout emitting both fluorescence (FL) and BL. The Cy5-CTZ exerts through-bond energy transfer (TBET)-based imaging modalities for mammalian cells. This novel derivative, Cy5-CTZ , is intrinsically fluorescent and emits NIR-shifted BL when reacting with an appropriate luciferase , such as Renilla luciferase (RLuc). The protocol exemplifies a unique live-cell imaging with Cy5-CTZ that is optically stable in physiological samples and rapidly permeabilize through plasma membrane and emit NIR-BL in live mammalian cells.


Assuntos
Carbocianinas/química , Imidazóis/química , Luciferases/metabolismo , Substâncias Luminescentes/química , Medições Luminescentes/métodos , Imagem Molecular/métodos , Pirazinas/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Animais , Células COS , Chlorocebus aethiops , Transferência de Energia
9.
Anal Chem ; 93(21): 7724-7731, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34000804

RESUMO

High-efficiency chemiluminescence (CL) resonance energy transfer (CRET) can be obtained by shortening the donor-acceptor distance and/or improving the luminescence efficiency of CRET acceptors. However, careful design and stringent experimental conditions are usually required for the ordered assembly of CRET acceptors on support materials to avoid aggregation-caused quenching problems. In this work, an aggregation-induced emission (AIE)-active fluorophore was disorderly adsorbed on the surface of layered double hydroxides (LDHs), which could exhibit high-efficiency luminescence. On the other hand, the positively charged LDHs can further adsorb peroxynitrite (ONOO-) on the surface of LDHs. Therefore, the LDH-supported AIE fluorophore could dramatically amplify weak CL signals from ONOO- donors as a result of ultra-high CRET efficiency by coupling the shorter donor-acceptor distance with efficient CRET acceptors. The proposed CL system has been successfully applied for the detection of NaNO2 in the concentration range from 1.0 to 100 µM with a detection limit as low as 0.5 µM. Satisfactory recoveries (98-106%) and good accuracy were achieved for sausage samples. Our success will open new avenues for the convenient design of high-efficiency CRET systems.


Assuntos
Luminescência , Medições Luminescentes , Transferência de Energia , Hidróxidos , Ácido Peroxinitroso
10.
Anal Chem ; 93(21): 7571-7578, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34013723

RESUMO

A quenchbody (Q-body) is an immunosensor comprising an antibody fragment containing an antigen-binding site that is site-specifically labeled with a fluorescent dye. The fluorescent dye of a Q-body is quenched in the absence of an antigen; however, its fluorescence recovers in the presence of an antigen, offering simple and rapid systems for antigen detection. In this study, we fused luciferase NanoLuc to a Q-body to construct a new immunosensor termed the "BRET Q-body" that can detect antigens based on the bioluminescence resonance energy transfer (BRET) principle. The resulting BRET Q-bodies for an osteocalcin peptide that emit three different emission colors could detect an antigen without the requirement of an external light source, based on ratiometric detection and color change with two wavelengths for the luciferase and fluorophore. Furthermore, the BRET Q-body produced unexpectedly higher responses up to 12-fold because of the increased BRET efficiency, probably associated with antigen-dependent dye movement. Thus, the BRET Q-body is a useful biosensor as a core of point-of-care tests.


Assuntos
Técnicas Biossensoriais , Anticorpos , Transferência de Energia , Imunoensaio , Luciferases , Medições Luminescentes
11.
ACS Sens ; 6(6): 2136-2140, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-34047541

RESUMO

Serological tests are crucial in a pandemic scenario, since they are a valuable tool to spot those citizens with potential immunity, specific regions with herd immunity or particular at-risk populations, as well as acquired immunity after vaccination. Hence, high-throughput, fast, cost-effective, and straightforward technologies facilitating interrogation of COVID-19 seroconversion are an existing need. Herein, we developed an innovative assay for the determination of COVID-19 seroconversion. Fluorophore-labeled SARS-CoV-2 spike receptor-binding domain recombinant protein (F-RBD) was discovered to operate as a bioprobe that emits a strong fluorescence upon COVID-19 antibody detection; however, F-RBD fluorescence was deactivated by graphene oxide-decorated surfaces when COVID-19 antibodies are absent in the sample. With a cost of less than 0.5 USD per test (at laboratory scale), the biosensing system offers optimum results within 42 min. To demonstrate that this technology is technically sound in a relevant environment, 34 human serum samples were analyzed and clearly differentiated, requiring a tiny amount of serum (1 µL to be later diluted in saline buffer).


Assuntos
COVID-19 , Anticorpos Antivirais , Transferência de Energia , Humanos , SARS-CoV-2 , Soroconversão
12.
ACS Sens ; 6(6): 2136-2140, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: covidwho-1246321

RESUMO

Serological tests are crucial in a pandemic scenario, since they are a valuable tool to spot those citizens with potential immunity, specific regions with herd immunity or particular at-risk populations, as well as acquired immunity after vaccination. Hence, high-throughput, fast, cost-effective, and straightforward technologies facilitating interrogation of COVID-19 seroconversion are an existing need. Herein, we developed an innovative assay for the determination of COVID-19 seroconversion. Fluorophore-labeled SARS-CoV-2 spike receptor-binding domain recombinant protein (F-RBD) was discovered to operate as a bioprobe that emits a strong fluorescence upon COVID-19 antibody detection; however, F-RBD fluorescence was deactivated by graphene oxide-decorated surfaces when COVID-19 antibodies are absent in the sample. With a cost of less than 0.5 USD per test (at laboratory scale), the biosensing system offers optimum results within 42 min. To demonstrate that this technology is technically sound in a relevant environment, 34 human serum samples were analyzed and clearly differentiated, requiring a tiny amount of serum (1 µL to be later diluted in saline buffer).


Assuntos
COVID-19 , Anticorpos Antivirais , Transferência de Energia , Humanos , SARS-CoV-2 , Soroconversão
13.
ACS Nano ; 15(5): 8965-8975, 2021 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-33988971

RESUMO

Chiral light-matter interactions have emerged as a promising area in biophysics and quantum optics. Great progress in enhancing chiral light-matter interactions have been investigated through passive resonators or spontaneous emission. Nevertheless, the interaction between chiral biomolecules and stimulated emission remains unexplored. Here we introduce the concept of a biological chiral laser by amplifying chiral light-matter interactions in an active resonator through stimulated emission process. Green fluorescent proteins or chiral biomolecules encapsulated in Fabry-Perot microcavity served as the gain material while excited by either left-handed or right-handed circularly polarized pump laser. Owing to the nonlinear pump energy dependence of stimulated emission, significant enhancement of chiral light-matter interactions was demonstrated. Detailed experiments and theory revealed that a lasing dissymmetry factor is determined by molecular absorption dissymmetry factor at its excitation wavelength. Finally, chirality transfer was investigated under a stimulated emission process through resonance energy transfer. Our findings elucidate the mechanism of stimulated chiral light-matter interactions, providing better understanding of light-matter interaction in biophysics, chiral sensing, and quantum biophotonics.


Assuntos
Lasers , Óptica e Fotônica , Transferência de Energia
14.
Small ; 17(25): e2101411, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34018682

RESUMO

Future applications of conjugated polymer particles (CPP) in medicine, organic photonics, and optoelectronics greatly depend on high performance and precisely adjustable optical properties of the particles. To meet these criteria, current particle systems often combine conjugated polymers with inorganic particles in core-shell geometries, extending the possible optical characteristics of CPP. However, current conjugated polymer particles are restricted to a single polymer phase composed of a distinct polymer or a polymer blend. Here, a synthetic toolbox is presented that enables the synthesis of monodisperse core-shell and core-shell-shell particles, which consist entirely of conjugated polymers but of different types in the core and the shells. Seeded and fed-batch dispersion polymerizations based on Suzuki-Miyaura-type cross-coupling are investigated. The different approaches allow accurate control over the created interface between the conjugated polymer phases and thus also over the energy transfer phenomena between them. This approach opens up completely new synthetic freedom for fine tuning of the optical properties of CPP, enabling, for example, the synthesis of individual white light-emitting particles.


Assuntos
Luz , Polímeros , Transferência de Energia , Tamanho da Partícula , Polimerização
15.
Talanta ; 231: 122243, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-33965056

RESUMO

Rapid and accurate detection of phosphate (Pi) in complex biological fluid is of critical importance for timely warning of Pi accumulation and monitoring Pi related pathological process. Up to date, various luminescent probes have been developed for Pi determination in aqueous media. However, the huge obstacles of the current probes suffer from the inherent issues such as time-consuming, tedious preparation and unavoidable background interference during Pi detection. To circumvent this limitation, we proposed a universal and facile strategy to fabricate a novel sensitizer-Ln3+@surfactant micelle probe with time-resolved luminescent (TRL) superiority through the self-assembly of sensitizer, Ln3+ and surfactant. Through this design, the sensitizer-Ln3+ chelate can be encapsulated into the surfactant constructed micelle and Ln3+ luminescence can be substantially lighted up through the effective energy transfer from the coordinated sensitizer and the assistance of Triton X-100. Such high TRL signal can be sensitively and specifically quenched by Pi, which was attributed to the specific coordination competition between sensitizer and Pi towards Ln3+. Benefitting from the background-free interference and highly sensitive TRL response of the sensitizer-Ln3+@surfactant probe, we achieved the rapid, selective and sensitive detection of Pi in the range of 0.5-120 µM with a limit of detection (LOD) of 0.19 µM. Furthermore, the accuracy of the proposed method based on the Ln3+ involved micelle probes was further verified through the quantitation of Pi in real biological samples.


Assuntos
Elementos da Série dos Lantanídeos , Transferência de Energia , Limite de Detecção , Luminescência , Fosfatos
16.
Biomacromolecules ; 22(6): 2393-2407, 2021 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-33973785

RESUMO

Peptide self-assembly is gathering much attention due to the precise control it provides for the arrangement of functional moieties for the fabrication of advanced functional materials. It is desirable to use a physical, chemical, or biological trigger that can control the self-assembly process. In the current article, we have applied an enzyme to induce the peptide self-assembly of an aromatic peptide amphiphile, which modulates the supramolecular order in the final gel phase material. We accessed diverse peptide hydrogels from identical gelator concentrations by simply changing the enzyme concentration, which controlled the reaction kinetics and influenced the dynamics of self-assembly. Depending upon the concentration of the enzyme, a bell-shaped relationship was observed in terms of intermolecular interactions, morphology, and properties of the final gel phase material. The access of non-equilibrium structures was further demonstrated by fluorescence emission spectroscopy, circular dichroism spectroscopy, atomic force microscopy, transmission electron microscopy, and rheology. This strategy is applied to construct a charge-transfer hydrogel by doping the donor hydrogel with an acceptor moiety, which exhibits efficient energy transfer. Interestingly, such structural control at the nanoscopic level can further tune the energy-transfer efficiency by simply modulating the enzyme concentration.


Assuntos
Dipeptídeos , Hidrogéis , Transferência de Energia , Peptídeos , Pirenos
17.
Analyst ; 146(11): 3474-3481, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-33913937

RESUMO

We present here a cyclic peptide ligand, cy(WQETR), that binds to the terbium ion (Tb3+) and enhances Tb3+ luminescence intensity through the antenna effect. This peptide was identified through screening a cyclic peptide library against Tb3+ with an apparent EC50 of 540 µM. The tryptophan residue from the peptide directly interacts with the Tb3+ ion, which provides access to a low-lying triplet excited state of the tryptophan. Direct excitation of this triplet state enables energy transfer to the Tb3+ ion and enhances Tb3+ luminescence intensity by 150 fold. We further showcase the application of this cy(WQETR)-Tb3+ system by demonstrating the detection of tromethamine with a detection limit of 0.5 mM.


Assuntos
Luminescência , Térbio , Transferência de Energia , Ligantes , Peptídeos Cíclicos
18.
Anal Chem ; 93(17): 6692-6697, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33886259

RESUMO

The freshness of meat has always been the focus of attention from consumers and suppliers for health and economic reasons. Usually, amine vapors, as one of the main components of the gas produced in the process of meat spoilage, can be used to monitor meat spoilage. Here, a new ratiometric cataluminescence (CTL) sensor based on energy transfer was developed to identify amine vapors and monitor meat freshness. After Tb doping, amine vapors exhibit a dual-wavelength (490 and 555 nm) property of CTL signals when reacted on the surface of Tb-doped La2O2CO3, and the ratio of I555 to I490 (R555/490) is a unique value for a given analyte within a wide range of concentrations. To illustrate the new sensor, 15 amine vapors were successfully identified using R555/490, including homologues and isomers. Besides, this sensor was used to monitor four meats, and the freshness of meats can be distinguished by cluster analysis successfully. Moreover, further discussion of energy-transfer phenomena and influence factors has facilitating effects on exploring the mechanism of energy transfer at the gas-solid interface.


Assuntos
Aminas , Carne , Transferência de Energia , Gases , Isomerismo , Carne/análise
19.
Anal Methods ; 13(18): 2092-2098, 2021 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-33870959

RESUMO

Nanosurface energy transfer (NSET)-based sensors have been widely developed using various pairs of nanomaterials including gold nanoparticles (AuNPs) and quantum dots (QDs). However, a low signal to background ratio is one of the most important problems that researchers are continually trying to solve. Herein, we present a 6-mercaptohexanol (MCH) modified MCH/DNA-Au-QD sensor for the detection of nucleic acids and MUC1. Interestingly, an unexpected effect of MCH was found in enhancing the fluorescence recovery ratio, therefore yielding a higher signal to background ratio. Through further investigation, we perceive the enhancement as a result of lowering of the NSET efficiency between free DNA-AuNPs and free DNA-QDs, which arises from the stretching of adsorbed DNA on the surface of AuNPs. The employment of MCH endowed the sensor with a wider linear range from 5 nM to 120 nM and a relatively lower LOD of 1.19 nM in nucleic acid detection, outperforming the original DNA-Au-QD sensor. Furthermore, the application of the sensor can be further extended to MUC1 detection. This study offers a better understanding of the NSET process between QDs and AuNPs and also initiates a new approach for the performance optimization of analogous NSET-based sensors.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Pontos Quânticos , Transferência de Energia , Ouro
20.
Biosens Bioelectron ; 182: 113175, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33799028

RESUMO

Ultrasounds (US) are one of the most used imaging techniques in medicine for assessing the physiological and pathological state of soft tissue. Apart from therapeutic applications, most of the interaction of the acoustic beams with tissues occur passively and without substantial modification to the physiology of the latter. However, US can also be used to remotely power implantable devices with sensing capabilities. In this study, we propose small-form devices interfaced with functionalized electrochemical electrodes for the detection of pH and lactate levels, powered by ultrasounds and data transmission through a Frequency Shift Keying (FSK) modulation technique. A custom-made piezoelectric transducer is responsible for converting the acoustic waves into electrical voltage at the device with operational levels as low as 0.5 V (power consumption of 10 µW) obtained from implantation distances of 50 mm inside tissue. This conjugated with the high sensitivity of the developed electrochemical sensors allows to detect and transmit local parameter variations below 0.1 pH (4.2 mV) and 1 mM lactate (70 nA). Potential applications include real-time access to intrabody tissue monitoring post-operatively, with the view of assessing proper soft tissue healing or infection detection by bacteria, as well as tissue cancer screening in structures such as the human breast.


Assuntos
Técnicas Biossensoriais , Ultrassom , Eletrodos , Transferência de Energia , Humanos , Monitorização Fisiológica
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