PREPARATION AND SURFACE PLASMON RESONANCE OF COPPER NANOCAP ARRAYS

2011 ◽  
Vol 25 (08) ◽  
pp. 599-604 ◽  
Author(s):  
GUI-NA XIAO ◽  
SHI-QING MAN ◽  
HUA-LI ZHANG ◽  
YAN-XIAO FENG

Copper nanocap arrays, consisting of a SiO 2 core with a Cu cap, were prepared by chemical synthesis combined with physical evaporation technique. The obtained samples were characterized by scanning electron microscopy, atomic force microscopy, X-ray diffraction, and ultraviolet-visible-near-infrared spectrophotometer. The copper nanocap arrays were found to exhibit tunable surface plasmon resonance (SPR) absorption peaks that were red-shifted as the ratio of the SiO 2 core diameter to the Cu cap thickness increased. While the cap thickness varied between 20 nm and 50 nm, the SPR peak shifted from 1650 nm to 1230 nm. While the core diameter varied between 140 nm and 400 nm, the longitudinal SPR peak shifted from 1243 nm to 1830 nm.

Biosensors ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 21
Author(s):  
Duygu Çimen ◽  
Nilay Bereli ◽  
Adil Denizli

In this study, we designed a simple, rapid, sensitive and selective surface plasmon resonance (SPR) sensor for detection of L-phenylalaine by utilizing molecular imprinting technology. l-phenylalanine imprinted and non-imprinted poly(2-hydroxyethyl methacrylate-methacryloyl-l-phenylalanine) polymeric films were synthesized onto SPR chip surfaces using ultraviolet polymerization. l-phenyalanine imprinted and non-imprinted SPR sensors were characterized by using contact angle, atomic force microscopy and ellipsometry. After characterization studies, kinetic studies were carried out in the concentration range of 5.0–400.0 μM. The limit of detection and quantification were obtained as 0.0085 and 0.0285 μM, respectively. The response time for the test including equilibration, adsorption and desorption was approximately 9 min. The selectivity studies of the l-phenylalanine imprinted SPR sensor was performed in the presence of d-phenylalanine and l-tryptophan. Validation studies were carried out via enzyme-linked immunosorbent analysis technique in order to demonstrate the applicability and superiority of the l-phenylalanine imprinted SPR sensor.


The Analyst ◽  
2000 ◽  
Vol 125 (2) ◽  
pp. 245-250 ◽  
Author(s):  
Molly M. Stevens ◽  
Stephanie Allen ◽  
Martyn C. Davies ◽  
Clive J. Roberts ◽  
Saul J. B. Tendler ◽  
...  

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2348 ◽  
Author(s):  
Katrin Niegelhell ◽  
Thomas Ganner ◽  
Harald Plank ◽  
Evelyn Jantscher-Krenn ◽  
Stefan Spirk

Lectins are a diverse class of carbohydrate binding proteins with pivotal roles in cell communication and signaling in many (patho)physiologic processes in the human body, making them promising targets in drug development, for instance, in cancer or infectious diseases. Other applications of lectins employ their ability to recognize specific glycan epitopes in biosensors and glycan microarrays. While a lot of research has focused on lectin interaction with specific carbohydrates, the interaction potential of lectins with different types of surfaces has not been addressed extensively. Here, we screen the interaction of two specific plant lectins, Concanavalin A and Ulex Europaeus Agglutinin-I with different nanoscopic thin films. As a control, the same experiments were performed with Bovine Serum Albumin, a widely used marker for non-specific protein adsorption. In order to test the preferred type of interaction during adsorption, hydrophobic, hydrophilic and charged polymer films were explored, such as polystyrene, cellulose, N,-N,-N-trimethylchitosan chloride and gold, and characterized in terms of wettability, surface free energy, zeta potential and morphology. Atomic force microscopy images of surfaces after protein adsorption correlated very well with the observed mass of adsorbed protein. Surface plasmon resonance spectroscopy studies revealed low adsorbed amounts and slow kinetics for all of the investigated proteins for hydrophilic surfaces, making those resistant to non-specific interactions. As a consequence, they may serve as favorable supports for biosensors, since the use of blocking agents is not necessary.


Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1497
Author(s):  
Nurul Illya Muhamad Fauzi ◽  
Yap Wing Fen ◽  
Nur Alia Sheh Omar ◽  
Silvan Saleviter ◽  
Wan Mohd Ebtisyam Mustaqim Mohd Daniyal ◽  
...  

In this study, synthesis and characterization of chitosan/maghemite (Cs/Fe2O3) composites thin film has been described. Its properties were characterized using Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and ultraviolet-visible spectroscopy (UV-Vis). FTIR confirmed the existence of Fe–O bond, C–N bond, C–C bond, C–O bond, O=C=O bond and O–H bond in Cs/Fe2O3 thin film. The surface morphology of the thin film indicated the relatively smooth and homogenous thin film, and also confirmed the interaction of Fe2O3 with the chitosan. Next, the UV-Vis result showed high absorbance value with an optical band gap of 4.013 eV. The incorporation of this Cs/Fe2O3 thin film with an optical-based method, i.e., surface plasmon resonance spectroscopy showed positive response where mercury ion (Hg2+) can be detected down to 0.01 ppm (49.9 nM). These results validate the potential of Cs/Fe2O3 thin film for optical sensing applications in Hg2+ detection.


2005 ◽  
Vol 389 (3) ◽  
pp. 665-673 ◽  
Author(s):  
Roland Gamsjaeger ◽  
Alexander Johs ◽  
Anna Gries ◽  
Hermann J. Gruber ◽  
Christoph Romanin ◽  
...  

Complexes formed between β2GPI (β2-glycoprotein I), a human plasma protein, and biological membranes are considered to be targets of macrophages and antiphospholipid autoantibodies involved in autoimmune diseases, such as antiphospholipid syndrome or systemic lupus erythematosus. The positively charged lysine-rich fifth domain of β2GPI facilitates its interaction with phospholipid membranes containing acidic phospholipids, which normally become exposed by apoptotic processes. In the present study, atomic force microscopy was applied to visualize the binding of β2GPI to a mixed phospholipid model membrane at physiological ionic strength. On supported lipid bilayers the formation of supramolecular assemblies of the protein with a height of approx. 3.3 nm was observed, suggesting a lateral agglomeration of β2GPI. Detailed analysis of kinetic constants using surface plasmon resonance revealed that the binding can be described by a two-state reaction model, i.e. a very fast interaction step, depending on the content of acidic phospholipids in the bilayer, and a second step with significantly lower kon and koff values. Taken together, our results suggest a biphasic interaction mechanism: a fast step of β2GPI binding to negatively charged lipids, mainly based on electrostatic interactions, and a slower phase of agglomeration of the protein on the bilayer surface accompanied by a protein-induced rigidification of the membrane, as revealed by electron paramagnetic resonance.


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