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Thin protein LB films as functional components within biosensors

Cabaj J., Chyla A., Sołoducho J.

Materials Science Poland

2009

Vol. 27, No. 3

684--692

Biomolecules can often be incorporated and immobilized into Langmuir-Blodgett (LB) films by using covalent immobilization of proteins with glutaraldehyde. Laccase from Cerrena Unicolor was incorporated into an LB film deposited on a glass substrate. The samples fabricated in such a way can be used for the detection of phenolic compounds. The function of enzyme immobilization was carried out by glutaraldehyde added to a film of stearic acid and laccase. The sensor sensitization was achieved by an amphiphilic N-alkyl-bis(thiophene)diphenylamine admixed into the film. The interlaced diphenylamine derivative was expected to facilitate the electron transfer thereby enhancing the sensor sensitivity.

The influence of ammonia, acetic acid and water vapour on the fluorescence of a 2-naphthol derivative in the Langmuir-Blodget films

Mirończyk A., Jankowski A., Chyla A., Ożyhar A., Dobryszycki P.

Materials Science Poland

2005

Vol. 23, No. 1

195--207

2-naphtholo-6-sulfonamide (NSDA) undergoes an excited state proton transfer to the environment when incorporated into Langmuir-Blodget (LB) films. We present the effect of acetic and hydrochloric acids, as well as ammonia and water vapour, on the fluorescence and absorption spectra of LB films. Acetic acid inhibits deprotonation of the excited state (ESDP), enormously (by up to 2 orders of magnitude) increases the fluorescence quantum yield (? ) of NSDA, blue-shifting its fluorescence band. The influence of hydrochloric acid on the fluorescence of NSDA is similar, although the enhancement of ? is lower in this case. Ammonia leads to the promotion of ESDP and an increase in ?. Water vapour does not change the fluorescence intensity markedly but it increases the probability of ESDP. These observations can be explained by the formation of a complex between acetic acid and NSDA, and by limited penetration of ammonia and water into the film.

Deposition and Characterization by Surface Plastmon Resonance of Langmuir-Blodgett Monolayers of Three Macrocyclic Conjugated Tetrapyrrole Compounds Exposed to Chlorine Gas

Honeybourne C. L., Portus D., Ratcliffe N.M., Richardson T., Ashwell G.J.

Polish Journal of Chemistry

2002

Vol. 76 / nr 2-3

367-376

Surface plasmon resonance (SPR) and quartz crystal microbalance (QCM) studies are described for tetrakis-tert-butylphthalocyanatoCu(II) and two new tetrakis-5,10,15,20- (substituted phenyl)-21H,23H-porphines. The Langmuir isotherms of the porphines, coupled with the layer thickness and contact area of the LB monolayers, show that these two compounds are not forming regular monolayer LB films, but are exhibiting extensive clumping on the subphase and on the substrates. The optical spectra and SPR of the porphine films did not exhibit noteworthy sensitivity to chlorine. In contrast the phthalocyanine gave good quality monolayers, which showed promise for sensing chlorine in the 1-10 ppm range.