Search

In a comprehensive picture of inclusion com- plex formation of the highly fluorescent dye coumarin-6 (C6) and betacyclodextrin (beta-CD), which was obtained using various fluorescence spectroscopic methods, it was demonstrated that up to three beta-CD rings can thread on the rod like dye molecule. Interaction of coumarins and modified coumarins with cellular organelles or proteins has been reported in several publications. Especially 7-amino- coumarins are characterized by unique properties like high fluorescence quantum yield and are thus already used successfully in different areas, like staining of fluorescent nanoparticles. We could show that Coumarin-6 made sol- uble by complexation with beta-cyclodextrin is able to stain eukaryotic cells specifically dependent on their origin and cellular behaviour. The staining reaction is indepen- dent from pH, is photo stable, and shows no cross talk with proteins in the cytoplasm and other staining procedures or erythrocytes. Staining with coumarin 6/cyclodextrin com- plexes can thus be used for fast discrimination of different cell types. Importantly, it could be shown that the ideal staining reaction is dependent on the stoichiometry of the complex-formation.

Cancer is one of the big killers of world population. The majority of cancers are diagnosed at a late stage, making a cure almost impossible. Fluorescence spectroscopy is an emerging diagnostic tool for various medical diseases including premalignant and malignant lesions. Fluorescence spectroscopy is a noninvasive technique and has been applied successfully for the diagnosis of multisystem cancers with high sensitivity and specificity. Fluorescence spectroscopy minimizes the need for repetitive biopsy, which is routine practice for cancer patient follow-up. But there are many aspects of this new diagnostic technique that should be discussed in future research to overcome limitations and challenges faced by this technique for diagnosis of cancers.

In this review article, the diagnostic applications of fluorescence spectroscopy (FS) in subspecialties of medical sciences are reviewed. The main purpose of this article is to present a critical report on various diagnostic applications of FS. Fluorescence spectroscopy is an emerging excellent diagnostic tool for many diseases, especially in the diagnosis of early stage cancers. Fluorescence spectroscopy is shown to be a more sensitive and rapid diagnostic tool with high efficiency compared to many routine medical diagnostic tools. However, there is still a great need for clinical trials and studies on a large scale to establish the validity of this new diagnostic technique. There is a need to highlight this issue among the scientific community. Current research, available instrumentation, and proposed areas that should be the focus of future research are presented and discussed in this review article.

Low temperature co-fired ceramic (LTCC) technology was originally developed for the realization of multilayer circuits of high reliability. It was recognized that LTCC-technology is a valuable development in thick film technology which launches new application areas as it becomes evident that complex three-dimensional structures can be easily realized. Aspects of the realization of a sophisticated biological monitoring module comprising a three-dimensional network of channels and cavities is demonstrated.

The receptors for vasoactive intestinal peptide (VIP), VPAC1-, VPAC2-, and PAC1-receptor are overexpressed by various tumor cells. VIP can target these receptors and transport conjugates into the cell. However, the use of VIP for tumor cell targeting is hampered by the peptides short half-lives due to enzymatic degradation. Because protamine-based nanoparticles (proticles) protect the peptide and serve as peptide depot, we explored the potential of proticles as carrier for VIP-conjugated molecules. The VIP-loaded proticles were stable as shown by Fluorescence Correlation Spectroscopy. With Confocal Laser Scanning Microscopy, we observed VIP-loaded proticles to specifically target the tumor cells. The cell binding triggered the substance release and conjugate internalization of VIP-Cy3 in vitro and ex vivo by human tumors. We observed VIP releasing proticle depots distributed in rat tissue and human tumors. Our findings warrant further studies to explore the proticles potential to enable peptide-mediated targeting for in vivo and clinical applications.

A 3-dimensional mesofluidic biological monitoring module has been successfully designed and fabricated using a low-temperature co-fired ceramic (LTCC) technology. This mesofluidic device consists of a network of micro-channels, a spherical mixing cavity and measuring ports. A selection of appropriate commercially available ceramic tapes has been chosen with regard to their biocompatibility performance. Specific processing procedures required for the realization of such a complex structure are demonstrated. Three dimensional numerical flow simulations have been conducted to characterize the concentration profiles of liquids at a specific measuring port and verified by experiment.

There are many diagnostic techniques and methods available for diagnosis of medically important microorganisms like bacteria, viruses, fungi and parasites. But, almost all these techniques and methods have some limitations or inconvenience. Most of these techniques are laborious, time consuming and with chances of false positive or false negative results. It warrants the need of a diagnostic technique which can overcome these limitations and problems. At present, there is emerging trend to use Fluorescence spectroscopy as a diagnostic as well as research tool in many fields of medical sciences. Here, we will critically discuss research studies which propose that Fluorescence spectroscopy may be an excellent diagnostic as well as excellent research tool in medical microbiology field with high sensitivity and specificity.

A system for observing bladder cancer cells in form of a miniaturized fluorescence microscope has been developed. Attention has turned to integrate this system in an existing LTCC (Low Temperature Cofired Ceramics) module. Software with a region detecting algorithm has been written to automatically detect the captured images. The cancer specimen was marked with hypericin, which is selective on bladder cancer cells. After coloring the specimen was excited with green light of a high power LED. The red emitting hypericin marked cells were captured by a CMOS chip and evaluated with the software to confirm or negate a suspicion of cancer.

Based on flow models applied in former analyses, three dimensional numerical flow simulations were performed for a spherical reactor cell of a biological monitoring module with respect to different inflow configurations and respective mass flow rates. Time - dependent simulations were performed for the case of dyed water and clear water flowing through different inlets at varying mass flow rates into the spherical cavity of reactor cell and channel system which connects the relevant measuring ports of the monitoring module. Spectroscopic analyses of light absorption at a port have been carried out and the results compared with the local concentration distribution predicted for this port by means of FE - analyses (Finite Element) using the CFD (Computational Fluid Dynamics) - program package of Fluent Inc.

Inhalative administration of vasoactive intestinal peptide (VIP) is a promising approach for the treatment of severe lung diseases. However, the clinical use of VIP is limited by the fact that the peptide is prone to rapid degradation mechanisms and proteolytic digestion. Accordingly, VIP exhibits a very short period of activity in the lung. To overcome this problem, we have designed a liposomal drug delivery system for VIP and characterized it in terms of its potential to protect VIP from enzymatic cleavage. The proteolytic conditions of the lung, the target site of aerosolic administered VIP, were mimicked by bronchoalveolar lavage fluid (BALF), a lung surfactant solution, obtained by fiberoptic bronchoscopy. Thus, the stability of VIP was assessed by its resistance to enzymatic degradation in BALF, using a combination of high pressure liquid chromatography with mass spectrometry. We found that free VIP was rapidly digested, whereas liposomal-associated VIP remained intact. By fluorescence spectroscopic techniques using fluorescent-labelled VIP we got strong indications that the tight association of VIP with the lipid membrane is only minimally affected upon incubation with BALF. Loading capacity and stability of EtCy3-VIP loaded liposomes were measured by fluorescence fluctuation spectroscopy. Finally, the protective properties of the liposomes were also expressed in the maintained biological activity of the peptide incubated with BALF.

In order to study the mixing of two liquids in a reaction chamber finite element analyses have been conducted. Different operating conditions like the filling of the empty reaction cell with liquids, mixing of fluids with different doping concentrations have been analyzed in dependence on varying flow velocities of liquids. To verify the results of simulation a reaction cell has been built up using LTCC-technology (low temperature cofired ceramic). Top and bottom side of the reaction cell were covered with a glass plate which enables the optical inspection and analyses of the sequence of mixing of coloured liquids.

Low temperature co-fired ceramic (LTCC) technology was originally developed for the realization of multilayer circuits of high reliability. It was recognized that LTCC technology is a valuable development in thick film technology, which launches new application areas as it becomes evident that complex three-dimensional structures can easily be realized. When considered for biological applications ceramic tape material must be proved with regard to its biocompatibility. A selection of appropriate commercially available ceramic tapes has been characterized in respect to the influence on proliferation, viability and adherence of cells. Aspects of realization of a complex biological monitoring module comprising a three-dimensional network of channels and cavities will be demonstrated.

Nanosized materials are increasingly used in medicine and biotechnology but originate also from various aerosol sources. A detailed understanding of their interaction with cells is a prerequisite for specific applications and appraisal of hazardous effects. Fluorescence fluctuation methods are applied to follow the time-course of the translocation and distribution of fluorescent 20 nm polystyrene nanoparticles with negative surface charges in HeLa cells under almost physiological conditions. The experimental results demonstrate that singular particles enter the cell without significant contribution by endocytotic mechanisms and are distributed within the cytoplasm. Subsequently aggregation is observed, which can be blocked by cytotoxins, like Genistein and Cytochalasin B, interfering with cellular uptake processes. The observed non-active uptake is due to non-specific interactions with the cell surface and could be responsible for distribution of nanometer-sized materials in tissue.