RESUMO
The behavior of the cinnamycin immobilized on the gold nanorod(AuNR) was investigated using surface plasmon resonance(SPR). For the comparison of the immobilized cinnamycin, the study for the free cinnamycin was also conducted. The bilayer was fabricated by tethering 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanols on a gold surface to form a monolayer and then using liposomes to adsorb an outer layer on the tethered-monolayer. The liposomes were prepared with a desired ratio of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine to 1,2-dioleoyl-sn-glycero-3-phosphocholine (0:100, 5:95, 10:90, 20:80, and 30:70). After the cinnamycin was injected on the bilayers, the specific binding between the cinnamycin and the bilayer was monitored with SPR. The inclusion of DOPE in the outer layer clearly led to the specific binding of the cinnamycin on the membranes. Specifically, the binding behavior of the immobilized was different from that of the free. For the free cinnamycin, the binding amount of cinnamycin at 10% was two times more than that at 5%. For the immobilized cinnamycin, the amounts were identical for both compositions. However, the rate was much faster for the immobilized cinnamycin at 10% than 5%, compared to that for the free at both compositions. This difference was attributed to the mean-molecular areas of the cinnamycin and DOPE, and the steric effect of the AuNR. For the effects of the heat and storage, the immobilized enzyme showed less decrease in the relative binding amount than the free one.
Assuntos
Bacteriocinas/farmacologia , Biomimética , Ouro , Lipossomos , Nanotubos , Peptídeos Cíclicos/farmacologia , Bacteriocinas/química , Biomimética/métodos , Ouro/química , Lipossomos/química , Nanotubos/química , Peptídeos Cíclicos/química , Fosfatidiletanolaminas/químicaRESUMO
Polydiacetylenes provide a good biological/chemical label-free detection system owing to their blue to red color change and fluorescence change from non-fluorescence to red fluorescence. One of the important factors to consider before applying polydiacetylenes to various sensors is to enhance the sensitivity against specific molecules. This paper reports two methods for stacking polydiacetylene vesicles for fluorescence signal enhancement of polydiacetylene on solid substrates. This focuses on how to achieve a highly sensitive sensor chip by introducing two strategies to immobilize the vesicles effectively on substrates. One method is layer-by-layer deposition through reactions of vesicles and avidins alternately on an avidin treated substrate. The other is to prepare a clustered vesicles solution by mixing the appropriate amount of a biotinylated vesicle solution and avidin solution, and then immobilize the clustered vesicles on the substrates. The former allows easy control of the layer thickness, whereas the latter can shorten the process time. These strategies can be applied to a range of biological/chemical sensors for fluorescence signal enhancement.
Assuntos
Técnicas Biossensoriais/métodos , Corantes Fluorescentes/química , Lipossomos/química , Polímeros/química , Poli-Inos/química , Avidina , Biotina , Ácidos Graxos Insaturados/química , Polímero Poliacetilênico , Sensibilidade e Especificidade , Espectrometria de Fluorescência , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Micro-arrayed polydiacetylene (PDA) vesicles mixed with phospholipids on glass slides were prepared for label-free detection of Escherichia coli. When E. coli bound to its antibodies chemically attached to polydiacetylene, the fluorescence of the vesicles was dramatically increased. The insertion of dimyristoyl phosphatidylcholine (DMPC) in the vesicles drastically reduced the response time for the fluorescence changes. Vesicles with 20-30% DMPC provided optimal results for bacterial detection. Fourier transform infrared (FTIR) spectra analysis suggested that DMPC insertion decreased the strength of hydrogen bonding among the amide and carboxylic acid groups of the polydiacetylene vesicles. Reduced bonding strength resulted in less rigid structure of the polydiacetylene polymer, allowing more rapid detection upon molecular recognition.
Assuntos
Técnicas Biossensoriais/métodos , Dimiristoilfosfatidilcolina/química , Polímeros/química , Poli-Inos/química , Análise Serial de Proteínas , Amidas/química , Anticorpos/química , Reações Antígeno-Anticorpo , Técnicas Biossensoriais/instrumentação , Ácidos Carboxílicos/química , Escherichia coli/química , Fluorescência , Vidro/química , Ligação de Hidrogênio , Modelos Moleculares , Estrutura Molecular , Polímero Poliacetilênico , Salmonella typhimurium/química , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de SuperfícieRESUMO
Self-assembled diacetylene vesicles were spotted and immobilized on aldehyde-modified glass substrates using conventional microarray technology. Irradiation of the immobilized diacetylenes allowed generation of nonfluorescent "blue-phase" polydiacetylene (PDA) arrays. Specific interaction of the PDA vesicle arrays with carbohydrates or poly(acrylic acid) solutions afforded fluorescent profiles.
Assuntos
Acetileno/análogos & derivados , Corantes Fluorescentes/química , Polímeros/química , Acetileno/química , Ácidos Graxos Insaturados/química , Microscopia de Fluorescência , Polímero Poliacetilênico , Poli-Inos , alfa-Ciclodextrinas/químicaRESUMO
To investigate the role of hydrogen-bonding on colorimetric transition of polydiacetylene supramolecules, novel diacetylene derivatives allowing various hydrogen-bonding states were synthesized by coupling carboxy-substituted (ortho-, meta-, and para-) anilide groups with a typical single-chain diacetylene lipid. One with a terminal carboxyl group at the meta position provided the resulting supramolecular Langmuir-Schaefer films with enhanced hydrogen-bonding, and hence resulted in unprecedented colorimetric reversibility under both thermal and pH stimuli.