Browsing by Subject "Fluorescence imaging"

Now showing 1 - 4 of 4

Open Access
Advances in nanoparticle‐based medical diagnostic and therapeutic techniques
(John Wiley & Sons, 2016-03-11) Sardan, Melis; Özkan, Alper Devrim; Zengin, Aygül; Tekinay, Ayşe B.; Güler, Mustafa O.; Güler, Mustafa O.; Tekinay, Ayşe B.
Advances in modern medicine have eliminated several major causes of human mortality and considerably extended life expectancies around the world; however, this increase in the global age average has also boosted the incidences of age‐associated disorders. These conditions, such as cancer, neurodegenerative disorders, and cardiovascular disease, severely decrease the quality of life for the affected but are highly polymorphic and often difficult to treat. This chapter describes the characteristics of nanoparticle (NP) contrast agents (CAs) proposed for use in medical imaging, and details the surface modification methods used to designate specific targets for their attachment. It then compares their effectiveness and toxicity compared to conventional methods of contrast enhancement, and discusses the contribution that nanoscience has had, and will have, on medical imaging and disease diagnosis at large.
Open Access
Concentric ring structures as efficient SERS substrates
(Institute of Electrical and Electronics Engineers, 2013) Cinel, N. A.; Cakmakyapan, S.; Ertas, G.; Özbay, Ekmel
Plasmonic nanopatterned structures that can work as highly efficient surface-enhanced Raman scattering (SERS) substrates are presented in this study. A 'coupled' concentric ring structure has been designed, fabricated, tuned, and compared to an 'etched' concentric ring structure and plain gold film via SERS experiments. The proposed design gives Raman signal intensity 630 times larger than plain gold film and 8 times larger than an 'etched' concentric ring structure. The surface plasmons were imaged with the fluorescence imaging technique and supporting numerical simulations were done.
Open Access
Fluorescent heterodoped nanotetrapods as synergistically enhancing positive and negative magnetic resonance imaging contrast agents
(American Chemical Society, 2016) Sharma, V. K.; Alipour, A.; Soran-Erdem Z.; Kelestemur Y.; Aykut, Z. G.; Demir, Hilmi Volkan
In this work, we report Mn-Fe heterodoped ZnSe tetrapod nanocrystals (NCs) synthesized to synergistically enhance contrast in both T1- and T2-weighted magnetic resonance imaging (MRI). The proposed NCs were prepared using a customized heteroarchitecture such that the manganese (Mn) is confined in the core and iron (Fe) in the branches of the tetrapods. The elemental composition and profile of these NCs were studied using X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, and inductively coupled plasma mass spectroscopy. Photoluminescence quantum yield of these heterodoped NCs in water is ∼30%. Magnetic measurements reveal the simultaneous presence of superparamagnetic and paramagnetic behavior in these NCs because of the coexistence of Mn2+ and Fe2+ dopants. Their potential as simultaneous positive and negative MRI contrast agents was demonstrated by relaxivity measurements and in vivo MRI. From the in vivo studies, we also found that these NCs (with a hydrodynamic diameter of 20 nm) are excreted from the body within 24 h after the injection. Therefore, these heterodoped tetrapods NCs, while being fluorescent and safe, hold great future as a synergistically enhancing dual-modal MRI contrast agent.
Open Access
Reaction-based BODIPY probes for selective bio-imaging
(Elsevier B.V., 2018) Kolemen, S.; Akkaya, E. U.
Complex intracellular environment of cells, which involves interaction of a large variety of bio-molecules, is a dynamic medium with full of important information that can be recovered as well as many unanswered questions. It is highly critical to image and track biologically relevant molecules in their native media without interfering with the regular cellular processes in order to gather as much data as possible to illuminate intricacies of the biological mechanisms. To that end, small-molecule fluorescent probes have been extensively developed during the last few decades with the help of current advances in imaging technologies. Although conventional probes utilizing non-covalent supramolecular interactions with the analyte of interest are successful, significant effort has been also put into the design of reaction-based probes (chemodosimeters). Chemodosimeters exploit selective reactions of analytes with fluorophores in attempt to improve the selectivity of the probes, address the limitations of former sensors and broaden the palette of useful probes. Various types of fluorophore scaffolds can be used in the design of chemodosimeters for visualization of different analytes. In this review, we highlight the 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) based chemodosimeters which have been used to image bio-thiols, reactive oxygen/nitrogen species, and gaseous molecules in living cells.