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Dilated cardiomyopathy (DCM), known as myocardial metabolic dysfunction, is recognized as a clinical condition characterized by left ventricular dilation or improper contraction of cardiac muscles in the absence of coronary atherosclerosis and hypertension. It is an independent risk factor for cardiac function caused by a hyperglycemic condition in diabetic patients leading to heart failure (HF), which renders the early diagnosis of DCM highly challenging. Hence, detection of early diagnostic biomarkers in blood serum to identify DCM conditions is quite requisite. Brain natriuretic peptide (BNP) is a well-recognized biomarker for heart failure and reported as an early diagnostic biomarker for DCM. In this work, we developed a terbium citrate based MoS2 nanosheet (NS) coupled immunoprobe for the sensitive detection of BNP. The antibody conjugated Tb-citrate complex exhibits green fluorescence, which is quenched by the introduction of MoS2 NS. On subsequent addition of antigen BNP, the fluorescence is enhanced because of specific antigen-antibody interaction. The probe is selective and sensitive toward BNP in a linear range from 30.76 to 849.85 pg/mL with a low LOD of 3.87 pg/mL. The probe is validated in spiked human serum samples with good recovery percentage.
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Cardiac troponin I (cTnI) is the most resorted biomarker for the detection of cardiovascular disease (CVD). The means of rapid quantification of cTnI levels in the blood can substantially minimize the risk of acute myocardial infarction and heart failure. A sensor for the non-enzymatic evaluation of cardiac troponin-I has been developed using fluorescent iron nanoclusters via a one-pot synthesis employing (BSA) as the template and reducing agent, and hydrogen peroxide as the additive. The fluorescence of Iron Nanocluster is quenched with graphene oxide (GO) via fluorescence resonance energy transfer (FRET) between conjugate iron nanoclusters and graphene oxide. The sensor shows a low detection limit of 0.013 ng/mL. The benefits of utilizing a non-enzymatic probe for detecting cardiac troponin I is that it avoids the need for enzymes and hence is economical, stable, and less impacted by environmental conditions such as temperature and pH. Non-enzymatic probes are more useful for clinical use since they are more stable and have a longer shelf life. The developed non-enzymatic probes are also highly selective and sensitive to the target analyte, making them suitable for the direct detection of cardiac troponin I in actual biological samples.
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Trimethylamine N-oxide (TMAO), a molecule produced by the microbiota, has been associated with human health and illness. Its early discovery in body fluids may affect our understanding of the pathophysiology and treatment of many illnesses. Therefore, our knowledge of the pathophysiology and diagnostics of disorders associated with TMAO might be enhanced by the creation of dependable and fast methods for TMAO detection. Therefore, we developed a fluorescent probe for detecting TMAO utilizing an on-off-on strategy. Bovine serum albumin (BSA)@AuNCs luminescence is effectively quenched by Mo4+ because BSA@AuNCs and Mo4+ have a strong binding relationship. Mo4+ ions can substantially decrease the emission intensity of gold nanoclusters by establishing a BSA@AuNCs-Mo system. Then, the luminescence of BSA@AuNCs was restored due to the interaction between Mo4+ and TMAO. A significant linear relationship was seen between the emission intensity and TMAO concentration within the 0-201 µM range, with a detection limit of 1.532 µM. Additionally, the method can measure TMAO in blood and urine samples.
Assuntos
Corantes Fluorescentes , Ouro , Nanopartículas Metálicas , Metilaminas , Soroalbumina Bovina , Animais , Bovinos , Humanos , Materiais Biocompatíveis/química , Fluorescência , Corantes Fluorescentes/química , Ouro/química , Teste de Materiais , Nanopartículas Metálicas/química , Metilaminas/química , Estrutura Molecular , Tamanho da Partícula , Soroalbumina Bovina/química , Espectrometria de FluorescênciaRESUMO
Dipicolinic acid (DPA) is a prominent biomarker for Anthrax disease. Bacillus anthracis bacterial endospores is composed of DPA as the significant component, which on over inhalation can cause severe health issues. Such contagious and life-threatening pathogens can be employed as bioweapons or biothreat agents for spreading bioterrorism which is a major risk for national security and public health concerns. Hence, effective detection or a surveillance system is essential for preventing the growth of bioterrorism events. Herein, we have developed a Terbium - 1,10 Phenanthroline (Tb-Phen) based lanthanide luminescence complex with bright green fluorescence. On addition of DPA, the green fluorescence is turn-off at a linear range from 0.6 to 4.762 mM. In this effect, 5D4- 7F5 transition caused by 1,10-phenanthroline to Tb3+ at 544 nm is restricted due to energy transfer quenching and Inner Filter Effect (IFE). The developed probe shows good sensitivity towards the detection of DPA with other coexisting biomolecules and ions with a low Limit of Detection (LOD) of 5.029 µM. The practical feasibility was evaluated in paper strip assay and extended in real samples such as human serum and tap water with satisfactory recovery percentage. Thereby, probe finds promising application in sensing of anthrax spore biomarker (DPA) and biothreat agents.
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Lead halide nanostructured perovskites are well known for their excellent photoluminescence and optoelectronic properties. However, lead toxicity and instability in moisture impedes its suitability for material use. Here we synthesized a highly efficient, lead free, economical, stable Cs2CuBr2Cl2 perovskite nanocrystals (PNCs) via Ligand Assisted Re-Precipitation (LARP) method which is less explored. The sensing application of the synthesized PNCs towards nitro explosives and other small organic compounds were studied. The probe exhibited high selectivity towards nitrobenzene with a lowest detection limit of 57.64 nM. The fluorescent emission intensity was drastically quenched upon the addition of 32 µM nitrobenzene. A Stern-Volmer plot was utilized for the quantification of fluorescence quenching. Further to investigate the quenching mechanism, time correlated single photon counting spectroscopy and other photoluminescence studies were performed pointing out the possibility of fluorescence resonance energy transfer. The work has been further extended to test the capability of the probe to detect nitrobenzene in real water samples and a good recovery percentage ranging from 93-98 % was obtained. Further, a paper strip assay was designed which successfully detected nitrobenzene and can be clearly noticed even with our naked eye making the probe an excellent sensor for nitrobenzene detection.
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A "turn-on" photon up conversion nano couple based on NaYF4: Yb, Tm UCNPs quenched with MnO2 nanosheet was developed for the rapid and selective detection of cTnT. Herein, MnO2 nanosheet hold on the surface of Antibody cTnT (Ab-cTnT) conjugated blue emitting up conversion nanoprobe (λem at 475 nm), which leads to quenching of fluorescence due to energy transfer from photon up conversion nanoparticles to MnO2 nanosheets. On introducing cTnT antigen to the system, the energy transfer process is hindered due to strong antigen -antibody interface on the surface. This in turn, influences the nano-couples positions and effectively separates up conversion nanoprobe from MnO2 nanosheets surface resulting in restriction to energy transfer process enabling fluorescence recovery. The developed probe shows a linear response towards cTnT in the range of 0.16-2.77 ng/mL with a Limit of Detection (LoD) of 0.025 ng/mL. The practical feasibility of the nanoprobe is performed with possible coexisting biomolecules. Biological study in human blood serum samples exhibited sufficient recovery percentage in the range of 92-103 % is obtained.
Assuntos
Compostos de Manganês , Óxidos , Fótons , Túlio , Troponina T , Óxidos/química , Humanos , Troponina T/sangue , Troponina T/análise , Troponina T/imunologia , Compostos de Manganês/química , Túlio/química , Limite de Detecção , Nanoestruturas/químicaRESUMO
A lanthanide complex based on europium (Eu) and chelidamic acid was synthesized (Eu-CHE) and characterized. The complex Eu-CHE exhibited intense luminescence at 615 nm under excitation at 300 nm and was further investigated for highly sensitive turn-off detection of l-kynurenine (l-kyn), a cancer biomarker. The probe detected l-kyn linearly from 6 nM to 0.2 µM with a limit of detection and limit of quantification of 1.37 and 4.57 nM, respectively. The probe was investigated for selectivity towards l-kyn among co-existing amino acids and further extended for detecting l-kyn from human serum and urine samples. A low-cost paper strip-based sensing platform was also developed for the visual detection of l-kyn.
Assuntos
Elementos da Série dos Lantanídeos , Neoplasias , Humanos , Cinurenina , Biomarcadores Tumorais , Neoplasias/diagnóstico , Aminoácidos , EurópioRESUMO
An enzymatic fluorescent probe is developed for the selective detection of glucose. In this work, a Bovine Serum Albumin stabilized gold nanocluster (BSA-AuNCs) was synthesized by microwave assisted method, and it is modified with glucose oxidase, thereby a fluorescent enzymatic sensor (BSA-AuNCs@GoX) was designed for the sensitive detection of glucose with a limit of detection of 0.03â mM. The red fluorescence exhibited by the probe is quenched by the production of H2O2 on addition of glucose via. a static quenching mechanism from UV visible absorption and Fluorescence lifetime results. The developed probe exhibits good selectivity and sensitivity with other coexisting molecular species such as glycine, creatinine, methionine, histidine, uric acid, albumin, and ions such as sodium, potassium, calcium, magnesium, zinc etc. that appear in the body fluid. The practical applicability was studied in paper strip and extended its reproducibility in biological matrixes such as human serum and urine and found a good recovery percentage of 94-101 %. By this way, we have fabricated an effective fluorescent enzymatic "turn-off" sensing probe for the detection of glucose.
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Corantes Fluorescentes , Glucose Oxidase , Glucose , Ouro , Nanopartículas Metálicas , Soroalbumina Bovina , Ouro/química , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Soroalbumina Bovina/química , Nanopartículas Metálicas/química , Animais , Humanos , Bovinos , Glucose/análise , Glucose/química , Corantes Fluorescentes/química , Técnicas Biossensoriais/métodos , Limite de Detecção , Espectrometria de Fluorescência , Glicemia/análiseRESUMO
Oral Squamous Cell Carcinoma (OSCC), a prevalent type of oral cancer originates in squamous cells that develop due to tobacco use, excess alcohol consumption, human papillomavirus infection, chronic irritation and weakened immune system. When detected early, survival rates of OSCC can be increased to more than 85%. Hence its early detection is crucial for appropriate management. Oxidative stress has a vital role in pathogenesis of various cancers including OSCC. Early detection of OSCC can be done by exploring serum Glutathione (GSH); an oxidative stress biomarker. Herein, we have developed two Silicon quantum dots (SiQDs); (L-methionine capped Silicon quantum dots (LSiQDs) and D-methionine capped Silicon quantum dots (DSiQDs)) and their fluorescence was quenched with Cu2+. The obtained Cu@LSiQDs and Cu@DSiQDs were then explored and compared for sensing GSH. Both the SiQDs were checked for selectivity and interference studies using coexisting biomolecules extended for sensing GSH from real samples. Moreover, a paper strip assay was also developed and compared.
RESUMO
Cardiac troponin I (cTnI) is a significant biomarker for acute heart attack. Hence, fast, economical, easy and real time monitoring of cardiac troponin I (cTnI) is of great importance in diagnosis and prognosis of heart failure in the healthcare domain. In this work, an immunoassay based on NaYF4:Yb/Ho based photon-upconversion nanoparticle (UCNP) with narrow emission peaks at 540 nm and 655 nm respectively, is synthesized. Then, it is encapsulated with amino functionalized silica using 3-aminopropyltriethoxysilane (APTES) to form APTES@SiO2-NaYF4:Yb/Ho UCNPs. When AuNPs is added to this system, the fluorescence is quenched by the electrostatic interaction with APTES@SiO2-NaYF4:Yb/Ho UCNPs, thereby exhibiting a FRET-based biosensor. When the cTnI antigen is introduced into the developed probe, an antibody-antigen complex is formed on the surface of the UCNPs resulting in fluorescence recovery. The developed sensor shows a linear response towards cTnI in the range from 0.1693 ng mL-1 to 1.9 ng mL-1 with a low limit of detection (LOD) of 5.5 × 10-2 ng mL-1. The probe exhibits adequate selectivity and sensitivity when compared with coexisting cardiac biomarkers, biomolecules and in real human serum samples.