Biofunctional structural design of SAW sensor chip surfaces in a microfluidic sensor system

Jung, Adrian; Gronewold, Thomas M. A.; Tewes, M.; Quandt, Eckhard; Berlin, Peter

doi:10.1016/j.snb.2006.11.040

Cited by 33 publications

(22 citation statements)

References 19 publications

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“…This observation may indicate that nonspecific binding can be detected and discriminated against based on the different spectral response. While the sensitivity is not yet comparable with commonly used labelbased and sandwiched-type detection methods such as ELISA, it is comparable with other direct detection techniques available in the literature, such as those reported by Jung et al, 63 a surface acoustic wave ͑SAW͒-based detection of thrombin ͑1 M͒ using an aptamer-functionalized sensor chip; and by Neumann et al, 15 a SERS-based direct detection of target molecules ͑PDGF and cocaine͒, wherein the randomness of the SERS spectra of the specific aptamer following exposure to the corresponding target molecule ͑1 M PDGF and 20 M cocaine͒ is monitored. We believe that further improvements ͑e.g., preconcentration of the sample on the SERS substrate͒ to the current technique will enhance its sensitivity.…”

Section: Resultsmentioning

confidence: 55%

Direct detection of aptamer-thrombin binding via surface-enhanced Raman spectroscopy

et al. 2010

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Abstract. In this study, we exploit the sensitivity offered by surfaceenhanced Raman scattering ͑SERS͒ for the direct detection of thrombin using the thrombin-binding aptamer ͑TBA͒ as molecular receptor. The technique utilizes immobilized silver nanoparticles that are functionalized with thiolated thrombin-specific binding aptamer, a 15-mer ͑5Ј-GGTTGGTGTGGTTGG-3Ј͒ quadruplex forming oligonucleotide. In addition to the Raman vibrational bands corresponding to the aptamer and blocking agent, new peaks ͑mainly at 1140, 1540, and 1635 cm −1 ͒ that are characteristic of the protein are observed upon binding of thrombin. These spectral changes are not observed when the aptamer-nanoparticle assembly is exposed to a nonbinding protein such as bovine serum albumin ͑BSA͒. This methodology could be further used for the development of label-free biosensors for direct detection of proteins and other molecules of interest for which aptamers are available.

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Section: Resultsmentioning

confidence: 55%

Direct detection of aptamer-thrombin binding via surface-enhanced Raman spectroscopy

et al. 2010

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“…Recently, polysiloxane was used for preparation of thin-film-composite membrane with biocompatibility and permselectivity [31], for covalent immobilization of enzyme [32], for preparation of hybrid matrix for covalent binding of enzyme [33]. Compared with other polymers such as polypyrrole [34] and polyvinylpyridine [35] used for linking of mediators, polysiloxane has additional advantages of increasing the activity and stability of entrapped enzyme [29].…”

Section: à2mentioning

confidence: 99%

A Nitrite Biosensor Based on Coimmobilization of Nitrite Reductase and Viologen‐Modified Polysiloxane on Glassy Carbon Electrode

2010

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Copper containing nitrite reductase (Cu-NiR) and viologen-modified sulfonated polyaminopropylsiloxane (PAPS-SO 3 H-V) were co-immobilized on glassy carbon electrode (GCE) by hydrophilic polyurethane (HPU) drop-coating, and the electrode was tested as a reagentless electrochemical biosensor for nitrite detection. The newly synthesized PAPS-SO 3 H-V as an electron transfer (ET) mediator between electrode and NiR was effective, and could be effectively immobilized in HPU membrane. The NiR and PAPS-SO 3 H-V co-immobilized GCE used as a nitrite biosensor showed the following performance factors: sensitivity ¼ 12.0 nA mM À1, limit of detection (LOD) ¼ 60 nM (S/N ¼ 3), linear response range ¼ 0 -18 mM (r 2 ¼ 0.996) and response time (t 90% ) ¼ 60 s, respectively. LineweaverBurk plot shows that apparent Michaelis -Menten constant (K app M Þ is 101 mM. Storage stability of the sensor is 51 days (80% of initial activity) in condition of storing in ambient air at room temperature. The sensor showed a relative standard deviation (RSD) of 3.2% (n ¼ 5) even in condition of injection of 1 mM nitrite. Interference study showed that common anions in water sample such as chlorate, chloride, sulfate and sulfite do not interfere with the nitrite detection. However, nitrate interfered with a relative sensitivity of 80% due to inherent character of the enzyme used.

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“…The partially reversible interactions of 6-deoxy-6-aminocellulose can be translated to their interactions with other biological macromolcules, that is, 6-deoxy-6-aminocellulose structures bind preferentially to glycoproteins and proteoglycans with sugar chains arranged like antennas, which act as receptor structures and could potentially act as an extracellular matrix (ECM) such as laminin, poly-l-lysine, or polyornithine. Another promising path is the covalent immobilization of a recognition molecule such as a protein [6] or an aptamer [7] through NH 2 groups on custom-designed aminocellulose self-assembled monolayers by using NH 2 -reactive bifunctional reagents. The observation may change the whole perception of carbohydrate molecular interaction phenomena.…”

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confidence: 99%

Protein‐like Oligomerization of Carbohydrates

et al. 2011

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Many proteins form noncovalent and thermodynamically reversible oligomers, and the state of self-association can dictate a proteins functionality. DNA-binding proteins are very often dimeric, while other proteins exist as trimers (e.g. chloramphenicol transacetylase), tetramers (e.g. hemoglobin), or higher-order reversible association products (tubulin, viral coat proteins, sickle cell hemoglobin), with clear functional roles that have never been observed for carbohydrates. Although weak self-association in a polysaccharide has been shown, [1] we show for the first time the presence of multiple oligomeric forms in a whole class of polymeric carbohydrates, 6-deoxy-6-aminocelluloses, using the hydrodynamic technique of analytical ultracentrifugation as a probe.Water-soluble aminocelluloses were prepared by the reaction of tosyl cellulose with an excess of di-or trifunctional amines, namely with tris(2-aminoethyl)amine yielding 6-deoxy-6-(2-(bis(2-aminoethyl)aminoethylamino) (BAEA) cellulose (1-3), as depicted in Figure 1. Similar structures were obtained from reactions of tosyl cellulose with 1,2-diaminoethane and 4,7,10-trioxa-1,13-tridecandiamine to give 6-deoxy-6-(2-aminoethyl)amino (AEA) cellulose 4 and 6-deoxy-6-(13-amino-4,7,10-trioxatridecaneamino) (ATOTA) cellulose 5, respectively (Supporting Information Figure 1). The degree of substitution (DS) ranged from 0.60 to 0.85 (Supporting Information Table 1). NMR spectroscopic studies revealed that the nucleophilic displacement takes place at the primary position 6 of the anhydroglucose unit (AGU). [2] Sedimentation coefficient distributions for the five different 6-deoxy-6-aminocelluloses were obtained from sedimentation velocity experiments in the analytical ultracentrifuge for six different solute loading concentrations (from 0.125 to 2.0 mg mL À1 ) in 0.1m phosphate-buffered saline (pH 6.8). Astonishingly, for every aminocellulose studied, the sedimentation coefficient distributions show between four and five discrete species with a stepwise increase in sedimentation coefficient. For example, the lowest sedimentation coefficient of the BAEA cellulose 1, prepared from cellulose with a degree of polymerization (DP) of 450, was detected at 1.8 Svedbergs (S). Additional species sedimenting at peak maxima of approximately 2.8, 4.0, 5.1, and 6.5 S were also clearly found using the SEDFIT algorithm of Dam and Schuck [3] (Figure 1). The measurements were repeated for two other BAEA celluloses prepared from cellulose with DP = 250, and comparable results were obtained (Figure 2 b, c). Peaks with sedimentation coefficients of approximately 1.6, 2.3, 3.1, 4.3, and 5.3 S have been found for an AEA cellulose (4) prepared from cellulose with DP = 450. Furthermore, the ATOTA cellulose 5 shows peaks sedimenting with maxima at approximately 1.7, 2.9, 4.3, and 5.5 S (Figure 2; Supporting Information Table 2). To check that the peaks were not artifacts of the analysis procedure, least-squares g(s) versus s distribution data were also obtained (Supporting Information Figure 3 a...

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Biofunctional structural design of SAW sensor chip surfaces in a microfluidic sensor system

Cited by 33 publications

References 19 publications

Direct detection of aptamer-thrombin binding via surface-enhanced Raman spectroscopy

Direct detection of aptamer-thrombin binding via surface-enhanced Raman spectroscopy

A Nitrite Biosensor Based on Coimmobilization of Nitrite Reductase and Viologen‐Modified Polysiloxane on Glassy Carbon Electrode

Protein‐like Oligomerization of Carbohydrates

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