With the methods of transganglionic transport of horseradish peroxidase(HRP) combined with postembedding colloidal gold stain immunoelectron microscopy, the shape and synaptic relationship of the trigeminal primary af...With the methods of transganglionic transport of horseradish peroxidase(HRP) combined with postembedding colloidal gold stain immunoelectron microscopy, the shape and synaptic relationship of the trigeminal primary afferent terminals containing substance展开更多
Objectives:The secondary products of lipid oxidation are one of the main factors inducing protein oxidation.The effects of oxidation treatment with malondialdehyde(MDA)on the immunoreactivity of amandin and its digest...Objectives:The secondary products of lipid oxidation are one of the main factors inducing protein oxidation.The effects of oxidation treatment with malondialdehyde(MDA)on the immunoreactivity of amandin and its digestion were studied.Materials and Methods:The rabbit IgG binding ability of amandin was analyzed by western blotting,and the changes in amandin oxidation and immunoreactivity during digestion of amandin with different degrees of oxidation were investigated in combination with an almond allergen enzyme-linked immunosorbent assay kit.Alteration of linear epitopes of amandin by oxidation was investigated by liquid chromatography-tandemmass spectrometry(LC-MS/MS).Results:The results showed that the immunoreactivity of amandin was significantly reduced after 1 mmol/L MDA and 100 mmol/L MDA treat-ment.However,the 1 mmol/L MDA treatment was owing to cleavage of linear epitope peptide in amandin and oxidation of the active amino acid.The 100 mmol/L MDA treatment was due to aggregation of amandin and significant decrease in its solubility.Oxidation also reduced di-gestibility of amandin and significantly affected immunoreactivity during digestion.LC-MS/MS also identified four oxidation-prone methionine sites(aa 264-274,298-308,220-240,and 275-297)in gamma conglutinin 1.Conclusions:MDA treatment reduced the immunoreactivity of amandin.MDA treatment also led to protein aggregation,which slowed down the digestion of amandin and altered the immunoreactivity of amandin during digestion.展开更多
The tropomyosin(TM)fractions of crab protems may cause allergic reactions in mdividuals susceptible to allergies;however,efficient and safe methods by which to reduce such allergenicity are not currently available.The...The tropomyosin(TM)fractions of crab protems may cause allergic reactions in mdividuals susceptible to allergies;however,efficient and safe methods by which to reduce such allergenicity are not currently available.Therefore,in this study,the effects of three different processing methods,i.e.,microwave,ultrasound,and high temperature-pressure(HTP)treatments,on the digestion stability of TM from Chinese mitten crab muscle and the allergenicity of TM digestion products were explored.sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that microwaving had little effect on the digestion stability of TM.In contrast,ultrasound and HTP treatments facilitated the degradation of TM.Similarly,Western blotting and inhibition ELISA indicated that the IgE-binding activity of TM was significantly reduced after treatment with ultrasound or HTP.Among the three different proces sing methods,HTP was the most effective method for improving digestibility of TM and reducing immunoreactivity.This finding provides new insights into treatments for crab allergies.展开更多
Objective:To study the changes of true insulin(TI) and immunoreactive insulin (IRI) in subjects with NGT, IGT and DM, to study the difference between true insulin and immunoreactive insulin in evaluating βcell functi...Objective:To study the changes of true insulin(TI) and immunoreactive insulin (IRI) in subjects with NGT, IGT and DM, to study the difference between true insulin and immunoreactive insulin in evaluating βcell function and insulin sensitivity. Methods:The levels of serum IRI and TI were determined in 54 cases with type Ⅱ diabetes mellitus(Group DM) ,43 cases with impaired glucose tolerance (Group IGT) and 75 cases with normal glucose tolerance (Group NGT). Then every group was subdivided into obese and non - obese subgroups according to body mass index. IRI was determined by RIA. TI was determined by ELISA using monoclonal antibody with no significant cross- reaction between insulin and proinsulin. The insulin resistance index (Homa- IR), pancreatic β- cell function index (Homa- B) and insulin release index (the ratio of the increment of insulin to that of plasma glucose 30 min after a glucose load,△ I30/△G30) were analyzed preliminarily. Results: The ratio of TI/IRI in non - obese subgroup with DM was lower than those in non obese subgroups with NGT and IGT (P＜0.01). The ratios of TI/Ipd in obese subgroups with IGT and DM were lower than those in obese subgroup with NGT(P＜0.05). The pancreatic β-cell function indexes (Homa-BIRI) of IRI in non- obese subgroups with IGT and DM were lower than that in non- obese subgroup with NGT(P＜0.05). The pancreatic β - cell function index (Homa- BTI) of TI in non- obese subgroup with IGT was lower than that in non obese subgroups with NGT ( P ＜ 0.05 ). The HomaBTI in non - obese subgroup with DM was lower than that in non - obese subgroups with NGT and IGT(P ＜0.01).The Homa - BIRI in obese subgroups of NGT, IGT and DM had no significant difference. Homa - BTI in obese subgroups with IGT and DM was lower than that in obese subgroup with NGT(P＜0.01). Conclusion:The ratio of TI/IRI was a good marker in evaluating β- cell function. Pancreatic β- cell function index (Homa- BTI) of TI was better than that of IRI.展开更多
Corynebacterium pseudotuberculosis is an infectious agent that occurs in small ruminants causing caseous lymphadenitis, and more rarely in humans causing lymphadenitis and pneumonia. The breeding small ruminants have ...Corynebacterium pseudotuberculosis is an infectious agent that occurs in small ruminants causing caseous lymphadenitis, and more rarely in humans causing lymphadenitis and pneumonia. The breeding small ruminants have great economic importance in Brazil. Rural farm workers and veterinary students who acquired this disease suffered from weakening symptoms for weeks, and the identification of the etiological agent was time-consuming and complex. Due to the low prevalence of case records, there is probably no available commercial diagnostic kit for C. pseudotuberculosis infection in humans. This study aimed to describe human seroreactivity to secreted antigens from C. pseudotuberculosis. Reactivity of serum from farm workers (n = 14), individuals who work with the bacillus at laboratory (n = 8) or individuals without contact (n = 25) was tested with secreted proteins from PAT10 strain of C. pseudotuberculosis by Western blotting. Samples of all (100%) farm workers showed reactivity to 31 kDa, 71 kDa and 164 kDa proteins, while laboratory workers showed 87.5%, 62.5 % and 37.5%, and no-contact 20%, 0% and 16%, respectively. All sera recognized the 275 kDa protein. Our data suggest that C. pseudotuberculosis secreted proteins are antigenic in humans and the recognition profiles allowed the identification of individuals with and without prior contact with this bacillus. This is the first paper which describes human reactivity to C. pseudotuberculosis in serum samples of workers in Brazil.展开更多
Some wheat gliadin proteins are strong allergens that may cause various symptoms of food allergies and baker’s asthma. The most immunoreactive ω-5 gliadin fractions are the main allergens in wheat dependent exercise...Some wheat gliadin proteins are strong allergens that may cause various symptoms of food allergies and baker’s asthma. The most immunoreactive ω-5 gliadin fractions are the main allergens in wheat dependent exercise induced anaphylaxis (WDEIA). While the allergenicity of ω-5 is quite well understood, knowledge about α, β, γ and ω-1.2 gliadins is much more scanty. This study examines allergenic properties of other fractions as compared to ω-5. Gliadins were extracted from flour of winter wheat (Triticum aestivum L.) cultivar Ostka strzelecka. Purified samples representing proteins belonging to α, β, γ, ω-1.2 and ω-5 classes were isolated using preparative gel electrophoresis. Immuno-reactivity and allergenic properties of these proteins were analyzed by ELISA using sera from allergic patients with elevated sIgE (> 2KU/L), and by skin prick test (SPT). ELISA showed that ω-5 and ω-1.2 differed considerabely from α-, β- and γ-gliadins in respect of immunoreactivity. Responses of both ω-gliadins were almost twice as high as for other fractions. Significant differences were also observed among individual ω-gliadin fractions as evidenced by ANOVA. SPT showed that patient with symptoms of baker’s asthma and WDEIA had a positive results to all gliadins tested. Another patient with baker’s asthma (but not WDEIA) reacted positively only to ω-5 gliadins. In two patients with skin allergy SPT were negative with all analyzed proteins. Results show ω-1.2 gliadins to be almost as immunorective as ω-5. The α-, β- and γ-gliadins also recognize specific IgE antibodies, but their binding capacity is only about half that of ω-fractions. This kind of immunoreactivity could still be important since a cumulative effect of individual fractions may intensify disease symptoms in allergic patients.展开更多
An insufficient cellular immune response seems to be critical for the immunopathogenesis of chronic hepatitis B virus infection.We have previously demonstrated no differences of T-lymphocyte subsets in blood between i...An insufficient cellular immune response seems to be critical for the immunopathogenesis of chronic hepatitis B virus infection.We have previously demonstrated no differences of T-lymphocyte subsets in blood between inactive hepatitis B s antigen(HBsAg) carriers and patients with HBeAg-negative chronic active hepatitis B.This study investigated the peripheral blood cytokine profile in patients with HBeAg-negative chronic active hepatitis B infection(Group A,n = 21) and inactive HBsAg carriers(Group B,n = 13).Serum cytokines [interferon(IFN)-γ,tumor necrosis factor-α,interleukin(IL)-1b,IL-4,IL-12,IL-10,IL-2,IL-5,IL-8] were analyzed by using flow cytometry.Patients with chronic active disease presented with significantly decreased levels of IFN-γ and IL-10 compared to inac-tive carriers(P = 0.048 and P = 0.008,respectively).In HBeAg-negative chronic active hepatitis B patients,a significant negative correlation of IFN-γ levels with serum hepatitis B viral load was noted(P = 0.021).In conclusion,patients with HBeAg-negative chronic active hepatitis B and HBsAg inactive carriers display a different cytokine profile.Decreased Th1 response observed in patients with chronic active hepatitis B could be implicated in the persistence of virus replication and ongoing progression of liver disease.展开更多
Celiac disease is an immune-mediated disorder that causes severe architectural disturbance in the small intestinal mucosa of genetically-predisposed individuals.Impaired absorption of multiple nutrients results and di...Celiac disease is an immune-mediated disorder that causes severe architectural disturbance in the small intestinal mucosa of genetically-predisposed individuals.Impaired absorption of multiple nutrients results and diarrhea and weight loss develop.Evidence has accumulated that a strict gluten-free diet can result in resolution of diarrhea,weight gain and normalization of nutrient malabsorption.In addition,histopathological changes also normalize,but this histopathological res-ponse appears to be time-dependent,sex-dependent and age-dependent.Compliance to a gluten-free diet is difficult and costly resulting in poor compliance and only a limited clinical response.This poses a risk for later long-term complications,including malignancy.A major practical clinical problem is the assessment of compliance to the gluten-free diet.Although symptoms may resolve and serological antibody markers may improve,multiple studies have documented ongoing architectural disturbance and inflammatory change,and with these continued inflammatory changes,a persistent risk for long-term complications.Recent immunological studies have suggested that peptides can be detected in both urine and fecal specimens that may be indicative of limited compliance.At the same time,multiple biopsy studies have demonstrated that complete normalization of the mucosa may occur in some patients within 6 mo of initiation of a gluten-free diet,but more often,up to 2 years or more may be required before repeated biopsies eventually show mucosal recovery and mucosal healing.展开更多
Substance P (SP)in the spinal cord is unevenly distributed and is concentrated in the dorsal horn, particularly in terminals of unmyelinated nociceptive primary afferent fibers. It indicates that SP may be an excitato...Substance P (SP)in the spinal cord is unevenly distributed and is concentrated in the dorsal horn, particularly in terminals of unmyelinated nociceptive primary afferent fibers. It indicates that SP may be an excitatory neurotransmitter released from nociceptive primary afferent nerve terminals. It was reported that SP in the spinal cord took part both in展开更多
Gap junctions and plasmodesmata are the major structures in maintaining the entity of organisms. They play an very important role in regulating and controlling the cell proliferation, tissue metabolism and orchestrati...Gap junctions and plasmodesmata are the major structures in maintaining the entity of organisms. They play an very important role in regulating and controlling the cell proliferation, tissue metabolism and orchestration. Although gap junctions and plasmodesmata appear to be very dissimilar, they have a number of functional similarities. Gap junctions have been studied intensively and isolated successfully from numerous tissues and sources. In contrast, until recently very little was known about the biochemical composition of plasmodesmata and especially about the proteins that are involved in gating process. They have not yet been isolated and characterized.展开更多
Increasing awareness concerning food safety problems has been driving the search for simple and efficient biochemical analytical methods.In this paper,we develop a portable electro-acoustic biosensor based on a film b...Increasing awareness concerning food safety problems has been driving the search for simple and efficient biochemical analytical methods.In this paper,we develop a portable electro-acoustic biosensor based on a film bulk acoustic resonator for the detection of pesticide residues in agricultural products.A shear mode ZnO film bulk acoustic resonator with a micro-machining structure was fabricated as a mass-sensitive transducer for the real-time detection of antibody-antigen reactions in liquids.In order to obtain an ultra-low detection level,the artificial antigens were immobilized on the sensing surface of the resonator to employ a competitive format for the immunoassays.The competitive immunoreactions can be observed clearly through monitoring the frequency changes.The presence of pesticides was detected through the diminution of the frequency shift compared with the level without pesticides.The limit of detection for carbaryl(a widely used pesticide for vegetables and crops)is2?10-10 M.The proposed device represents a potential alternative to the complex optical systems and electrochemical methods that are currently being used,and represents a significant opportunity in terms of simplicity of use and portability for on-site food safety testing.展开更多
文摘With the methods of transganglionic transport of horseradish peroxidase(HRP) combined with postembedding colloidal gold stain immunoelectron microscopy, the shape and synaptic relationship of the trigeminal primary afferent terminals containing substance
基金supported by from the National Natural Science Foundation of China(No.31860431).
文摘Objectives:The secondary products of lipid oxidation are one of the main factors inducing protein oxidation.The effects of oxidation treatment with malondialdehyde(MDA)on the immunoreactivity of amandin and its digestion were studied.Materials and Methods:The rabbit IgG binding ability of amandin was analyzed by western blotting,and the changes in amandin oxidation and immunoreactivity during digestion of amandin with different degrees of oxidation were investigated in combination with an almond allergen enzyme-linked immunosorbent assay kit.Alteration of linear epitopes of amandin by oxidation was investigated by liquid chromatography-tandemmass spectrometry(LC-MS/MS).Results:The results showed that the immunoreactivity of amandin was significantly reduced after 1 mmol/L MDA and 100 mmol/L MDA treat-ment.However,the 1 mmol/L MDA treatment was owing to cleavage of linear epitope peptide in amandin and oxidation of the active amino acid.The 100 mmol/L MDA treatment was due to aggregation of amandin and significant decrease in its solubility.Oxidation also reduced di-gestibility of amandin and significantly affected immunoreactivity during digestion.LC-MS/MS also identified four oxidation-prone methionine sites(aa 264-274,298-308,220-240,and 275-297)in gamma conglutinin 1.Conclusions:MDA treatment reduced the immunoreactivity of amandin.MDA treatment also led to protein aggregation,which slowed down the digestion of amandin and altered the immunoreactivity of amandin during digestion.
基金supported by the earmarked fund for the Anhui Provincial Modern Agri-industry Technology Research System(AHCYJSTX-08)the China Agriculture Research System of MOF and MARA(CARS-48)。
文摘The tropomyosin(TM)fractions of crab protems may cause allergic reactions in mdividuals susceptible to allergies;however,efficient and safe methods by which to reduce such allergenicity are not currently available.Therefore,in this study,the effects of three different processing methods,i.e.,microwave,ultrasound,and high temperature-pressure(HTP)treatments,on the digestion stability of TM from Chinese mitten crab muscle and the allergenicity of TM digestion products were explored.sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that microwaving had little effect on the digestion stability of TM.In contrast,ultrasound and HTP treatments facilitated the degradation of TM.Similarly,Western blotting and inhibition ELISA indicated that the IgE-binding activity of TM was significantly reduced after treatment with ultrasound or HTP.Among the three different proces sing methods,HTP was the most effective method for improving digestibility of TM and reducing immunoreactivity.This finding provides new insights into treatments for crab allergies.
文摘Objective:To study the changes of true insulin(TI) and immunoreactive insulin (IRI) in subjects with NGT, IGT and DM, to study the difference between true insulin and immunoreactive insulin in evaluating βcell function and insulin sensitivity. Methods:The levels of serum IRI and TI were determined in 54 cases with type Ⅱ diabetes mellitus(Group DM) ,43 cases with impaired glucose tolerance (Group IGT) and 75 cases with normal glucose tolerance (Group NGT). Then every group was subdivided into obese and non - obese subgroups according to body mass index. IRI was determined by RIA. TI was determined by ELISA using monoclonal antibody with no significant cross- reaction between insulin and proinsulin. The insulin resistance index (Homa- IR), pancreatic β- cell function index (Homa- B) and insulin release index (the ratio of the increment of insulin to that of plasma glucose 30 min after a glucose load,△ I30/△G30) were analyzed preliminarily. Results: The ratio of TI/IRI in non - obese subgroup with DM was lower than those in non obese subgroups with NGT and IGT (P＜0.01). The ratios of TI/Ipd in obese subgroups with IGT and DM were lower than those in obese subgroup with NGT(P＜0.05). The pancreatic β-cell function indexes (Homa-BIRI) of IRI in non- obese subgroups with IGT and DM were lower than that in non- obese subgroup with NGT(P＜0.05). The pancreatic β - cell function index (Homa- BTI) of TI in non- obese subgroup with IGT was lower than that in non obese subgroups with NGT ( P ＜ 0.05 ). The HomaBTI in non - obese subgroup with DM was lower than that in non - obese subgroups with NGT and IGT(P ＜0.01).The Homa - BIRI in obese subgroups of NGT, IGT and DM had no significant difference. Homa - BTI in obese subgroups with IGT and DM was lower than that in obese subgroup with NGT(P＜0.01). Conclusion:The ratio of TI/IRI was a good marker in evaluating β- cell function. Pancreatic β- cell function index (Homa- BTI) of TI was better than that of IRI.
文摘Corynebacterium pseudotuberculosis is an infectious agent that occurs in small ruminants causing caseous lymphadenitis, and more rarely in humans causing lymphadenitis and pneumonia. The breeding small ruminants have great economic importance in Brazil. Rural farm workers and veterinary students who acquired this disease suffered from weakening symptoms for weeks, and the identification of the etiological agent was time-consuming and complex. Due to the low prevalence of case records, there is probably no available commercial diagnostic kit for C. pseudotuberculosis infection in humans. This study aimed to describe human seroreactivity to secreted antigens from C. pseudotuberculosis. Reactivity of serum from farm workers (n = 14), individuals who work with the bacillus at laboratory (n = 8) or individuals without contact (n = 25) was tested with secreted proteins from PAT10 strain of C. pseudotuberculosis by Western blotting. Samples of all (100%) farm workers showed reactivity to 31 kDa, 71 kDa and 164 kDa proteins, while laboratory workers showed 87.5%, 62.5 % and 37.5%, and no-contact 20%, 0% and 16%, respectively. All sera recognized the 275 kDa protein. Our data suggest that C. pseudotuberculosis secreted proteins are antigenic in humans and the recognition profiles allowed the identification of individuals with and without prior contact with this bacillus. This is the first paper which describes human reactivity to C. pseudotuberculosis in serum samples of workers in Brazil.
基金This work was carried out with financial support from The Polish Ministry of Science by research grant No.NN310 162238.
文摘Some wheat gliadin proteins are strong allergens that may cause various symptoms of food allergies and baker’s asthma. The most immunoreactive ω-5 gliadin fractions are the main allergens in wheat dependent exercise induced anaphylaxis (WDEIA). While the allergenicity of ω-5 is quite well understood, knowledge about α, β, γ and ω-1.2 gliadins is much more scanty. This study examines allergenic properties of other fractions as compared to ω-5. Gliadins were extracted from flour of winter wheat (Triticum aestivum L.) cultivar Ostka strzelecka. Purified samples representing proteins belonging to α, β, γ, ω-1.2 and ω-5 classes were isolated using preparative gel electrophoresis. Immuno-reactivity and allergenic properties of these proteins were analyzed by ELISA using sera from allergic patients with elevated sIgE (> 2KU/L), and by skin prick test (SPT). ELISA showed that ω-5 and ω-1.2 differed considerabely from α-, β- and γ-gliadins in respect of immunoreactivity. Responses of both ω-gliadins were almost twice as high as for other fractions. Significant differences were also observed among individual ω-gliadin fractions as evidenced by ANOVA. SPT showed that patient with symptoms of baker’s asthma and WDEIA had a positive results to all gliadins tested. Another patient with baker’s asthma (but not WDEIA) reacted positively only to ω-5 gliadins. In two patients with skin allergy SPT were negative with all analyzed proteins. Results show ω-1.2 gliadins to be almost as immunorective as ω-5. The α-, β- and γ-gliadins also recognize specific IgE antibodies, but their binding capacity is only about half that of ω-fractions. This kind of immunoreactivity could still be important since a cumulative effect of individual fractions may intensify disease symptoms in allergic patients.
文摘An insufficient cellular immune response seems to be critical for the immunopathogenesis of chronic hepatitis B virus infection.We have previously demonstrated no differences of T-lymphocyte subsets in blood between inactive hepatitis B s antigen(HBsAg) carriers and patients with HBeAg-negative chronic active hepatitis B.This study investigated the peripheral blood cytokine profile in patients with HBeAg-negative chronic active hepatitis B infection(Group A,n = 21) and inactive HBsAg carriers(Group B,n = 13).Serum cytokines [interferon(IFN)-γ,tumor necrosis factor-α,interleukin(IL)-1b,IL-4,IL-12,IL-10,IL-2,IL-5,IL-8] were analyzed by using flow cytometry.Patients with chronic active disease presented with significantly decreased levels of IFN-γ and IL-10 compared to inac-tive carriers(P = 0.048 and P = 0.008,respectively).In HBeAg-negative chronic active hepatitis B patients,a significant negative correlation of IFN-γ levels with serum hepatitis B viral load was noted(P = 0.021).In conclusion,patients with HBeAg-negative chronic active hepatitis B and HBsAg inactive carriers display a different cytokine profile.Decreased Th1 response observed in patients with chronic active hepatitis B could be implicated in the persistence of virus replication and ongoing progression of liver disease.
文摘Celiac disease is an immune-mediated disorder that causes severe architectural disturbance in the small intestinal mucosa of genetically-predisposed individuals.Impaired absorption of multiple nutrients results and diarrhea and weight loss develop.Evidence has accumulated that a strict gluten-free diet can result in resolution of diarrhea,weight gain and normalization of nutrient malabsorption.In addition,histopathological changes also normalize,but this histopathological res-ponse appears to be time-dependent,sex-dependent and age-dependent.Compliance to a gluten-free diet is difficult and costly resulting in poor compliance and only a limited clinical response.This poses a risk for later long-term complications,including malignancy.A major practical clinical problem is the assessment of compliance to the gluten-free diet.Although symptoms may resolve and serological antibody markers may improve,multiple studies have documented ongoing architectural disturbance and inflammatory change,and with these continued inflammatory changes,a persistent risk for long-term complications.Recent immunological studies have suggested that peptides can be detected in both urine and fecal specimens that may be indicative of limited compliance.At the same time,multiple biopsy studies have demonstrated that complete normalization of the mucosa may occur in some patients within 6 mo of initiation of a gluten-free diet,but more often,up to 2 years or more may be required before repeated biopsies eventually show mucosal recovery and mucosal healing.
文摘Substance P (SP)in the spinal cord is unevenly distributed and is concentrated in the dorsal horn, particularly in terminals of unmyelinated nociceptive primary afferent fibers. It indicates that SP may be an excitatory neurotransmitter released from nociceptive primary afferent nerve terminals. It was reported that SP in the spinal cord took part both in
文摘Gap junctions and plasmodesmata are the major structures in maintaining the entity of organisms. They play an very important role in regulating and controlling the cell proliferation, tissue metabolism and orchestration. Although gap junctions and plasmodesmata appear to be very dissimilar, they have a number of functional similarities. Gap junctions have been studied intensively and isolated successfully from numerous tissues and sources. In contrast, until recently very little was known about the biochemical composition of plasmodesmata and especially about the proteins that are involved in gating process. They have not yet been isolated and characterized.
基金supported by the National Science Foundation of China(No.61101027)Qingdao Science and Technology Program(No.12-1-4-6-(8)-jch)+2 种基金Shangdong Provincial Young and Middle-Aged Scientists Research Awards Fund(No.BS2012DX032)Shandong Provincial Natural Science Foundation(No.ZR2013FM018)SDUST Research Funds(Nos.2011KYJQ101 and 2012KYTD103)
文摘Increasing awareness concerning food safety problems has been driving the search for simple and efficient biochemical analytical methods.In this paper,we develop a portable electro-acoustic biosensor based on a film bulk acoustic resonator for the detection of pesticide residues in agricultural products.A shear mode ZnO film bulk acoustic resonator with a micro-machining structure was fabricated as a mass-sensitive transducer for the real-time detection of antibody-antigen reactions in liquids.In order to obtain an ultra-low detection level,the artificial antigens were immobilized on the sensing surface of the resonator to employ a competitive format for the immunoassays.The competitive immunoreactions can be observed clearly through monitoring the frequency changes.The presence of pesticides was detected through the diminution of the frequency shift compared with the level without pesticides.The limit of detection for carbaryl(a widely used pesticide for vegetables and crops)is2?10-10 M.The proposed device represents a potential alternative to the complex optical systems and electrochemical methods that are currently being used,and represents a significant opportunity in terms of simplicity of use and portability for on-site food safety testing.
