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Selected papers from the latest issue:
Preparation And Evaluation Of An Immunoaffinity Sorbent For The Analysis Of Opioid Peptides By On-Line Immunoaffinity Solid-Phase Extraction Capillary Electrophoresis-Mass Spectrometry
15 December 2011, 23:27:25
Publication year: 2011
Source: Analytica Chimica Acta, Available online 14 December 2011
Silvia Medina-Casanellas, Fernando Benavente, José Barbosa, Victoria Sanz-Nebot
In this study, we explored a procedure for the preparation of an immunoaffinity (IA) sorbent for the analysis of opioid peptides by on-line immunoaffinity solid-phase extraction capillary electrophoresis-mass spectrometry (IA-SPE-CE-MS). We followed a site-specific antibody immobilization approach based on the covalent attachment of the oxidized antibodies through their carbohydrate moieties to hydrazide silica particles, using a polyclonal antibody against Endomorphin 1 and 2 (End1 and End2). The main features of the IA sorbent were studied, such as the amount of hydrazide groups and antibodies attached onto oxidized diol silica particles. Once the procedure was optimized, standard solutions of End1 and End2 were used in order to establish the IA-SPE-CE-MS methodology. Acceptable repeatability, reproducibility and linearity range values were obtained for the proposed methodology. The limits of detection (LODs) of 1 ng mLwere approximately 100-fold better than those obtained by CE-MS. Selectivity of the IA sorbent was good but some cross-reactivity against Dynorphin A (1-7) was observed when a mixture of several opioid peptides was analyzed. Human plasma samples spiked with End1 and End2 were also analyzed and both peptides could be detected down to 100 ng mL.
Source: Analytica Chimica Acta, Available online 14 December 2011
Silvia Medina-Casanellas, Fernando Benavente, José Barbosa, Victoria Sanz-Nebot
In this study, we explored a procedure for the preparation of an immunoaffinity (IA) sorbent for the analysis of opioid peptides by on-line immunoaffinity solid-phase extraction capillary electrophoresis-mass spectrometry (IA-SPE-CE-MS). We followed a site-specific antibody immobilization approach based on the covalent attachment of the oxidized antibodies through their carbohydrate moieties to hydrazide silica particles, using a polyclonal antibody against Endomorphin 1 and 2 (End1 and End2). The main features of the IA sorbent were studied, such as the amount of hydrazide groups and antibodies attached onto oxidized diol silica particles. Once the procedure was optimized, standard solutions of End1 and End2 were used in order to establish the IA-SPE-CE-MS methodology. Acceptable repeatability, reproducibility and linearity range values were obtained for the proposed methodology. The limits of detection (LODs) of 1 ng mLwere approximately 100-fold better than those obtained by CE-MS. Selectivity of the IA sorbent was good but some cross-reactivity against Dynorphin A (1-7) was observed when a mixture of several opioid peptides was analyzed. Human plasma samples spiked with End1 and End2 were also analyzed and both peptides could be detected down to 100 ng mL.
Highlights
► We prepared an IA sorbent for the analysis of opioid peptides by IA-SPE-CE-MS. ► We followed a site-specific antibody immobilization approach. ► The main features of the IA sorbent were studied. ► Endomorphin 1 and 2 were analyzed in standards and plasma samples to achieve the best LODs.Amperometricl-lactate biosensor based on screen-printed carbon electrode containing cobalt phthalocyanine, coated with lactate oxidase-mesoporous silica conjugate layer
15 December 2011, 23:27:25
Publication year: 2011
Source: Analytica Chimica Acta, Available online 14 December 2011
Takeshi Shimomura, Touru Sumiya, Masatoshi Ono, Tetsuji Ito, Taka-aki Hanaoka
A novel amperometric biosensor for the measurement ofl-lactate has been developed. The device comprises a screen-printed carbon electrode containing cobalt phthalocyanine (CoPC-SPCE), coated with lactate oxidase (LOD) that is immobilized in mesoporous silica (FSM8.0) using a polymer matrix of denatured polyvinyl alcohol; a Nafion layer on the electrode surface acts as a barrier to interferents. The sampling unit attached to the SPCE requires only a small sample volume of 100 μL for each measurement. The measurement ofl-lactate is based on the signal produced by hydrogen peroxide, the product of the enzymatic reaction. The behavior of the biosensor, LOD-FSM8.0/Naf/CoPC-SPCE, was examined in terms of pH, applied potential, sensitivity and operational range, selectivity, and storage stability. The sensor showed an optimum response at a pH of 7.4 and an applied potential of +450 mV. The determination range and the response time forl-lactate were 18.3 μM–1.5 mM and approximately 90 s, respectively. In addition, the sensor exhibited high selectivity forl-lactate and was quite stable in storage, showing no noticeable change in its initial response after being stored for over 9 months. These results indicate that our method provides a simple, cost-effective, high-performance biosensor forl-lactate
Source: Analytica Chimica Acta, Available online 14 December 2011
Takeshi Shimomura, Touru Sumiya, Masatoshi Ono, Tetsuji Ito, Taka-aki Hanaoka
A novel amperometric biosensor for the measurement ofl-lactate has been developed. The device comprises a screen-printed carbon electrode containing cobalt phthalocyanine (CoPC-SPCE), coated with lactate oxidase (LOD) that is immobilized in mesoporous silica (FSM8.0) using a polymer matrix of denatured polyvinyl alcohol; a Nafion layer on the electrode surface acts as a barrier to interferents. The sampling unit attached to the SPCE requires only a small sample volume of 100 μL for each measurement. The measurement ofl-lactate is based on the signal produced by hydrogen peroxide, the product of the enzymatic reaction. The behavior of the biosensor, LOD-FSM8.0/Naf/CoPC-SPCE, was examined in terms of pH, applied potential, sensitivity and operational range, selectivity, and storage stability. The sensor showed an optimum response at a pH of 7.4 and an applied potential of +450 mV. The determination range and the response time forl-lactate were 18.3 μM–1.5 mM and approximately 90 s, respectively. In addition, the sensor exhibited high selectivity forl-lactate and was quite stable in storage, showing no noticeable change in its initial response after being stored for over 9 months. These results indicate that our method provides a simple, cost-effective, high-performance biosensor forl-lactate
Highlights
► Lactate biosensor based on screen-printed electrode, simple to fabricate and use, have been developed. ► Activated electrode containing cobalt-phthalocyanine lowers operating potential of the biosensor. ► Mesoporous silica and nafion layers ensure excellent stability and high selectivity. ► Only a small sample volume is required for the measurement. ► High-performance lactate biosensor is obtained with a simple and cost effective wayElectrochemiluminescence Biosensor For The Assay Of Small Molecule And Protein Based On Bifunctional Aptamer And Chemiluminescent Functionalized Gold Nanoparticles
15 December 2011, 23:27:25
Publication year: 2011
Source: Analytica Chimica Acta, Available online 14 December 2011
Ying Chai, Dayong Tian, Hua Cui
An electrochemiluminescence (ECL) biosensor for simultaneous detection of adenosine and thrombin in one sample based on bifunctional aptamer andN-(aminobutyl)-N-(ethylisoluminol) functionalized gold nanoparticles (ABEI-AuNPs) was developed. A streptavidin coated gold nanoparticles modified electrode was utilized to immobilize biotinylated bifunctional aptamer (ATA), which consisted of adenosine and thrombin aptamer. The ATA performed as recognition element of capture probe. For adenosine detection, ABEI-AuNPs labeled hybridization probe with a partial complementary sequence of ATA reacted with ATA, leading to a strong ECL response ofN-(aminobutyl)-N-(ethylisoluminol) enriched on ABEI-AuNPs. After recognition of adenosine, the hybridization probe was displaced by adenosine and ECL signal declined. The decrease of ECL signal was in proportion to the concentration of adenosine over the range 5.0 × 10- 5.0 × 10 M with a detection limit of 2.2 × 10 M. For thrombin detection, thrombin was assembled on ATA modified electrode via aptamer-target recognition, another aptamer of thrombin tagged with ABEI-AuNPs was bounded to another reactive site of thrombin, producing ECL signals. The ECL intensity was linearly with the concentration of thrombin from 5 × 10 M to 5 × 10 M with a detection limit of 1.2 × 10 M. In the ECL biosensor, adenosine and thrombin can be detected when they coexisted in one sample and a multi-analytes assay was established. The sensitivity of the present biosensor is superior to most available aptasensors for adenosine and thrombin. The biosensor also showed good selectivity towards the targets. Being challenged in real plasma sample, the biosensor was confirmed to be a good prospect for multi-analytes assay of small molecules and proteins in biological samples.
Source: Analytica Chimica Acta, Available online 14 December 2011
Ying Chai, Dayong Tian, Hua Cui
An electrochemiluminescence (ECL) biosensor for simultaneous detection of adenosine and thrombin in one sample based on bifunctional aptamer andN-(aminobutyl)-N-(ethylisoluminol) functionalized gold nanoparticles (ABEI-AuNPs) was developed. A streptavidin coated gold nanoparticles modified electrode was utilized to immobilize biotinylated bifunctional aptamer (ATA), which consisted of adenosine and thrombin aptamer. The ATA performed as recognition element of capture probe. For adenosine detection, ABEI-AuNPs labeled hybridization probe with a partial complementary sequence of ATA reacted with ATA, leading to a strong ECL response ofN-(aminobutyl)-N-(ethylisoluminol) enriched on ABEI-AuNPs. After recognition of adenosine, the hybridization probe was displaced by adenosine and ECL signal declined. The decrease of ECL signal was in proportion to the concentration of adenosine over the range 5.0 × 10- 5.0 × 10 M with a detection limit of 2.2 × 10 M. For thrombin detection, thrombin was assembled on ATA modified electrode via aptamer-target recognition, another aptamer of thrombin tagged with ABEI-AuNPs was bounded to another reactive site of thrombin, producing ECL signals. The ECL intensity was linearly with the concentration of thrombin from 5 × 10 M to 5 × 10 M with a detection limit of 1.2 × 10 M. In the ECL biosensor, adenosine and thrombin can be detected when they coexisted in one sample and a multi-analytes assay was established. The sensitivity of the present biosensor is superior to most available aptasensors for adenosine and thrombin. The biosensor also showed good selectivity towards the targets. Being challenged in real plasma sample, the biosensor was confirmed to be a good prospect for multi-analytes assay of small molecules and proteins in biological samples.
