The droplet deposition methods in Raman spectroscopy have received considerable attention in the field of analytical sensing focusing on effective pre-concentration of the studied analyte (coffee-ring effect or small spots). This review covers different analytical applications of drop-coating deposition Raman scattering (DCDRS) and droplet deposition surface-enhanced Raman scattering (SERS) spectroscopy. Two main advantages of droplet deposition Raman techniques are considered: the drying-induced segregation of the components from the mixtures (such as body fluids) and the sensitivity of detection of various analytically important molecules. Some recent advanced applications, including clinical cancer diagnosis, are discussed and summarized. Finally, the potential and further perspectives of the droplet deposition Raman methods for analytical studies are introduced.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Evaporation of a drop of biomolecular solution on a solid surface typically creates a ring-shaped drying pattern, formed by the so-called "coffee ring" effect. The size and shape of the "coffee ring" pattern is strongly dependent on the properties of the surface as well as on the deposited molecular solution or suspension. In this paper, we tested six types of surfaces differing in their physico-chemical surface characteristics (contact angles, wettability and roughness) as well as in the presence or absence of a base metal layer. The tested surfaces include two fluorocarbon coated metallic surfaces (commercial SpectRIM™ from Tienta Sciences, Inc. based on a smoothed stainless steel and non-commercial aluminium surface), three silanized glass surfaces and polished CaF2. The results showed that the formation of a "coffee ring" was influenced by surface wettability as well as by lipid concentration in the drop. Drop coating deposition Raman (DCDR) spectroscopy was used to compare the ability of the tested surfaces to preconcentrate molecules in the ring and therefore improve detection sensitivity. It was shown that surfaces with a contact angle of 90° and higher produce smaller drying patterns than more hydrophilic surfaces. In these drying patterns, the model liposomes were more efficiently preconcentrated, which resulted in a higher Raman signal of the liposomes. The applicability of surfaces with static contact angles less than 90°, high water contact angle hysteresis and no metal layer (silanized glass, CaF2) is limited to samples with high liposome concentrations.
- Publikační typ
- časopisecké články MeSH
Time-resolved microspectrofluorimetry and fluorescence microscopy imaging-two complementary fluorescence techniques-provide important information about the intracellular distribution, level of uptake and binding/interactions inside living cell of the labeled molecule of interest. They were employed to monitor the "fate" of AS1411 aptamer labeled by ATTO 425 in human living cells. Confocal microspectrofluorimeter adapted for time-resolved intracellular fluorescence measurements by using a phase-modulation principle with homodyne data acquisition was employed to obtain emission spectra and to determine fluorescence lifetimes in U-87 MG tumor brain cells and Hs68 non-tumor foreskin cells. Acquired spectra from both the intracellular space and the reference solutions were treated to observe the aptamer localization and its interaction with biological structures inside the living cell. The emission spectra and the maximum emission wavelengths coming from the cells are practically identical, however significant lifetime lengthening was observed for tumor cell line in comparison to non-tumor one.
- Klíčová slova
- AS1411 aptamer, Aptamer, Fluorescence microscopy imaging, Intracellular fluorescence, Phase-modulation lifetime measurement,
- MeSH
- aptamery nukleotidové metabolismus MeSH
- časové faktory MeSH
- fluorescenční mikroskopie metody MeSH
- fluorescenční spektrometrie metody MeSH
- intracelulární prostor genetika metabolismus MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- oligodeoxyribonukleotidy genetika metabolismus MeSH
- sekvence nukleotidů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- AGRO 100 MeSH Prohlížeč
- aptamery nukleotidové MeSH
- oligodeoxyribonukleotidy MeSH
Drop-coating deposition Raman (DCDR) spectroscopy is based on the measurement of a sample that has been preconcentrated by being dried on a special hydrophobic plate. In addition to its higher sensitivity, the advantage of DCDR over the conventional Raman spectroscopy is the small sample volume needed, the lack of interference from solvents, and the capability of segregating any impurities present and separating components in more complex samples. In this study, DCDR spectroscopy was employed to investigate the complex of the cationic copper(II) 5,10,15,20-tetrakis(1-methyl-4-pyridyl) porphyrin (CuTMPyP) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes. Drop-coating deposition Raman spectra were treated using factor analysis (FA), which led to the following conclusions: (i) the distribution of CuTMPyP in the complex is not homogenous, (ii) the DCDR technique segregates complexed and noncomplexed parts of the sample, (iii) the spectral changes caused by the drying process and by the interaction of CuTMPyP with the DPPC liposomes can be distinguished, and (iv) the porphyrin molecules interacting with DPPC affect both the order-disorder properties of the lipid chains and the lipid head.
- MeSH
- liposomy chemie metabolismus MeSH
- membrány umělé * MeSH
- porfyriny chemie metabolismus MeSH
- Ramanova spektroskopie metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- liposomy MeSH
- membrány umělé * MeSH
- porfyriny MeSH
Drop coating deposition Raman (DCDR) spectroscopy was used to study liposomes (DPPC and asolectin) with growing proportion of cholesterol. Deposited samples of both liposomes on special hydrophobic surface formed a dried drop with a circular shape with a ring of concentrated liposomes at the outer edge. The presence of cholesterol in liposome causes a diminishing of the drop size and an increasing in diameter of the ring, but DPPC with 20% of cholesterol forms the compact drop without the ring. Raman spectra contain characteristics of both lipids and cholesterol, liposomes do not change their initial phase state after drying. Spectral mapping shows that maximum Raman intensity originated from the inner part of the ring. Our results suggest that DCDR spectroscopy can be used for studying lipids containing cholesterol in situ.
- Klíčová slova
- Asolectin, Cholesterol, DPPC, Drop coating deposition Raman spectroscopy, Liposome,
- MeSH
- 1,2-dipalmitoylfosfatidylcholin chemie MeSH
- cholesterol chemie MeSH
- fosfatidylcholiny chemie MeSH
- hydrofobní a hydrofilní interakce MeSH
- liposomy chemie MeSH
- Ramanova spektroskopie * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- 1,2-dipalmitoylfosfatidylcholin MeSH
- asolectin MeSH Prohlížeč
- cholesterol MeSH
- fosfatidylcholiny MeSH
- liposomy MeSH
Interaction, i.e., cellular uptake and intracellular distribution, of synthetic modified antisense oligonucleotide with the B16 melanoma cell line was studied using cationic polyene antibiotic, amphotericin B 3-dimethylaminopropyl amide, as a carrier vector. The antisense oligonucleotide--dT(15) oligomer analogue containing isopolar, nonisosteric, phosphonate-based internucleotide linkages 3'-O-P-CH(2)-O-5'--was labeled with fluorescent tetramethylrhodamine marker. The oligonucleotide itinerancy across the cell membrane and its distribution inside the cell was visualized using fluorescence microimaging. During the first several hours a strong preference staining of the cell nucleus was found. Fluorescence lifetime measurements from the intracellular environment (confocal laser microspectrofluorimeter, frequency domain phase/modulation technique in 1 to 200 MHz frequency region) yielded two spectral components of 4.9 and 1.4 ns lifetime, respectively. While the former component correlates with the previously characterized effect of the fluorophore binding to biomolecular targets in membranes and/or cytoplasm, the latter component is newly observed and its possible origin is discussed.
- MeSH
- amfotericin B farmakologie MeSH
- antisense oligonukleotidy farmakokinetika MeSH
- buněčná membrána metabolismus MeSH
- buněčné jádro metabolismus MeSH
- cytoplazma metabolismus MeSH
- fluorescenční spektrometrie metody MeSH
- kationty MeSH
- konfokální mikroskopie MeSH
- lasery MeSH
- melanom experimentální MeSH
- myši MeSH
- oligonukleotidy farmakokinetika MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- amfotericin B MeSH
- amphotericin B3-(N'-dimethylamino)propylamide MeSH Prohlížeč
- antisense oligonukleotidy MeSH
- kationty MeSH
- oligonukleotidy MeSH
