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Sol–gel encapsulation has been used as the basis for detecting cortisol by an immunoassay approach. Previous research showed that antibodies immobilized in the pores of a sol–gel derived silica were able to bind cortisol and be used as an immunosensor. However, this approach was not effective when measuring cortisol levels in human serum because of interference from other fluorescence sources. The present paper describes a protocol which overcomes these limitations and enables sol–gel immunoassays to effectively measure cortisol in human serum over the physiological range of cortisol blood concentrations in an adult (2–28 μg/dL). The method involves a standard additions approach in which various amounts of cortisol are added to the serum. The cortisol concentration values obtained with our sol–gel immunoassay were typically within 10% of the values obtained by traditional analytical methods. The protocol presented here represents a significant contribution to sol–gel sensing and immunoassays in particular, because of the ability to detect an analyte in human serum. In addition, this work reports the first comparison between results from a sol–gel immunosensor and an alternative immuno-binding method for analyte detection.

Optical absorption spectra of three dinitroaromatic radical anions, 2,7-dinitro-9,9-dimethylfluorene ([1.sup.*-]), 4,4'dinitrobiphenyl ([2.sup.*-]), and 4,4'-dinitrotolane ([3.sup.*-]) in solvents THF, HMPA, and MeCN show both an unresolved broad band characteristic of charge-localized mixed valence species (Robin-Day classification Class II), and a vibronically structured band of the delocalized species (Class III). With decreasing solvent reorganization energy, a greater portion of the compounds become charge-delocalized. In particular, [1.sup.*-] with the greatest coupling, is almost entirely composed of the delocalized species in all solvents. An intense Raman mode is used to identify the charge-bearing unit as the nitrobenzene moiety. Resonance Raman profiles are utilized to gain detailed information of vibrational modes. The out-of-phase ring lengthening stretch mode is 00 observed to be enhanced at higher excitation energies, corresponding to the absorption band of the Class II species, while the in-phase ring lengthening stretch mode, a totally symmetric vibration, is most strongly enhanced in the absorption region of the Class III species. Resonance Raman profiles support the solvent-dependent coexistence of Class II and Class III molecules of the same chemical composition. Key words: mixed valence, resonance Raman spectroscopy, dinitroaromatic, neighboring orbital model. Les spectres d'absorption optique des trois anions radicalaire dinitroaromatiques, 2,7-dinitro-9,9-dimethylfluorene ([1.sup.*-]), 4,4'-dinitrobiphenyl ([2.sup.*-]) et 4,4'-dinitrotolane ([3.sup.*-]) dans les solvants THF, HMPA et MeCN presentent une bande large non resolue caracteristique des especes chargees a valence mixte (classe II dans la classification de Robin-Day) et une structure de bande vibronique propre aux especes delocalisees (classe III). Lorsque l'energie de reorganisation du solvant diminue, une plus grande partie des composes deviennent porteuses de charges delocalisees. En particulier, f-, qui presente le couplage le plus important, est presque entierement compose des especes delocalisees dans tous les solvants. Un mode Raman intense est utilise pour determiner que l'unite porteuse de charge est la moitie nitrobenzene. On a recours a des profils de resonance Raman pour obtenir les informations detaillees de modes vibrationnels. On observe que le mode d'etirement-allongement de cycle hors phase est meilleur ameliore a des energies d'excitation elevees, qui correspondent a la bande d'absorption des especes de la classe II, tandis que le mode d'etirement-allongement de cycle en phase, une vibration totalement symetrique, est tres fortement ameliore dans la region d'absorption des especes de la classe III. Les profils de resonance Raman favorisent la coexistence, dependante du solvant, des molecules des classes II et III de composition chimique identique. [Traduit par la Redaction] Mots-cles : valence mixte, spectroscopie Raman de resonance, dinitroaromatique, modele des orbitales voisines., Introduction Mixed valence molecules have two or more equivalent sites that can have different oxidation states in either the ground or excited state. (1-4) These systems are often denoted as [...]

A comparison of rate constants measured for an intervalence (IV) compounds with electron-transfer parameters obtained from its optical absorption spectrum is done using resonance Raman analysis. It is suggested that the Zhu-Nakamura preexponential factor provides good consistency for the ESR rate constants using a value, averaged single-mode which closer to those predicted from the resonance Raman spectroscopic data but need slightly higher electronic coupling than [V.sub.Hush].

A well-resolved vibronic fine structure is disclosed by the luminescence spectra of [[(tpy).sub.2]Ir[(CN-t-Bu).sub.2]](C[F.sub.3]S[O.sub.3]) in methylcyclohexane glass and frozen n-nonane at 15 K. The analysis has shown that the most highly distorted normal modes involve atomic motions on the tpy ligand, which is consistent with the metal to ligand/ligand centered assignment of the electronic transition.

The optical spectra of seven protected diaminoaromatic radical cations that have nine-bond bridges between the amino groups are studied. The linking units are C[H.sub.2], C[H.sub.2]C[H.sub.2], NMe, S, S[O.sub.2], and C=O and (the unlinked benzidine) H,H are also studied.

Intramolecular photoinduced electron transfer from a hydrazine unit to an aromatic group is studied by Raman spectroscopy and electron absorption spectroscopy. It is seen that the lowest excited state of the hydrazine-substituted anthracene compound arises from a hydrazine-to-anthracene charge transfer and the geometrical changes that the hydrazine group undergoes upon photoinduced electron transfer are provided by the interaction of the resonance Raman (rR) profile.

Photochemical charge separation within aromatic hydrazines and the effect of exited-state intervalence in dihydrazines are studied. The results suggest that the most noticeable consequence of the exited-state intervalence is, under 60% as large for Hy2(super 14)NA compared to Hy(super 1)NA and for a significantly smaller Strokes shift for the distributed compared to the monosubstituted compounds Hy2(super 26)NA compared to Hy(super 2)NA.

The preparation of thin films simultaneously doped with two different luminescent molecules located in two different spatially separated regions is reported. Fluorescence and photoexcitation spectra of rhodamine 6G (R6G) in amorphous and structured thin films show that it is located inside the surfactant micelles of structured thin films.

A model for the quantitative treatment of dihydrazine diradical dication, which possesses mixed valence excited states is introduced and utilized for explaining the observed spectroscopic consequences. Results indicate that the excited-state mixed valence could play an important role in the electronic spectra of many organic and inorganic compounds.

Resonance Raman spectroscopy, electronic absorption spectroscopy and the time-dependent theory of spectroscopy are used to analyze the intervalence electron transfer properties of a strongly delocalized p-Phenylenediamine. The importance of symmetric normal coordinates, in addition to the asymmetric coordinate, are discussed.

Methods of making mesostructured sol-gel silicate thin films containing two different luminescent molecules deliberately placed in two different spatially separated regions in one step, one-pot are developed and demonstrated. The strategies take advantage of the different chemical and physical properties of the inorganic silicate framework, the hydrophobic organic interior, and the ionic interface between them.

The resonance Raman excitation profiles of cyclopentadienylcobalt cyclooctadiene, CpCoCOD contain pronounced decreases in intensity in the region of the lowest energy ligand field absorption band. This deenhancement is caused by interference between the ligand field state and nearby metal to ligand charge-transfer states.

A self-contained nanocapsule for nonspecific cytotoxic anticancer drug delivery and release activated by an enzyme and an alternating magnetic field (AMF) is introduced. This specific prodrug-like drug delivery platform is based on an esterase, an oligomer-based separating barrier, and an ester-linked anticancer peptide melittin encapsulated together in the enlarged pore spaces of the mesoporous silica nanoparticles. A superparamagnetic iron oxide nanoparticle core embedded in the center acts as a nanoheater to stimulate a cascade drug release. Each pore space was designed as a reaction nanovial for the activation of the drug release when the solution inside the nanovial is heated. By employing a thermoresponsive separating barrier as a shield of the peptide drug as well as a separator between the ester-containing peptides and the esterase, the nonspecific cytotoxic effect of the drug and off-target drug release are avoided because the drugs remain inactive in the absence of AMF stimulation. When AMF heating actuates the removal of the separating barrier and exposes the peptide drugs to the enzymes, drug release can be activated. In vivo antitumor experiments further revealed that the nanocapsules exhibited excellent biocompatibility and high tumor-targeting/inhibiting efficiency. The selected esterase, which is in close proximity to the ester-containing peptide drug, efficiently cleaves the ester bonds, thereby causing a catalytic release of peptide drugs and intensified anticancer efficacy. [ABSTRACT FROM AUTHOR]