Applications of biophysical techniques in drug discovery and development

Editorial: Applications of biophysical techniques in drug discovery and developmen

Kapilarna elektroforeza - osnovni principi i primena

Electrophoresis is a process in which charged species (ions or colloidal particles) are separated based upon differential migration rates in an electrical field. The first sophisticated electrophoresis apparatus was developed by Swedish scientist Arne Tiselius (Nobel Prize for chemistry in 1948). In the subsequent years electrophoresis separations were the backbone of much research by biochemists and molecular biologists. But as classical electrophoresis is slow, labor intensive technique with poor reproducibility, a new technique - capillary electrophoresis was developed in the mid 1980s. Electrophoresis separation is done in capillaries that are usually 25-75 μm wide (small sample volumes are used (1-10 nL)), under electric field which strength can rise up to 700 V/cm without significant system heating. Therefore capillary electrophoresis (CE) is recognized as a powerful analytical separation technique that brings speed, quantitation reproducibility, and automation to the inherently highly resolving but labor intensive methods of electrophoresis. CE has established itself as an important and widely utilized technique for routine analytical separations isolation, and analysis of proteins, polynucleotides, and other biopolymers.Kapilarna elektroforeza je jedna od danas najčešće korišćenih tehnika za razdvajanje supstanci. Efikasnost, brzina i jednostavnost u podešavanju selektivnosti, osnovne su prednosti koje je vrlo često čine odabranom tehnikom odvajanja i određivanja čak i u konkurenciji sa visoko efikasnom tečnom hromatografijom (HPLC). Elektroforeza je, u opštem smislu, metoda razdvajanja naelektrisanih supstanci prema brzinama kretanja u električnom polju. Prvo razdvajanje supstanci na bazi različitih brzina kretanja u električnom polju izvedeno je krajem 20-ih godina XX veka. Švedski hemičar Arne Tiselius (Arne Wilhelm Kaurin Tiselius, 1902-1971) doktorirao je 1930. godine sa tezom "Tehnika pokretnih granica u proučavanju elektroforeze proteina". U godinama koje su sledile Tiselius se bavio istraživanjima pojava difuzije i adsorpcije kod prirodnih zeolita, ali se od 1936. godine vraća razvijanju tehnike elektroforetskih razdvajanja i ispitivanjima mogućnosti upotrebe fizičkih metoda za rešavanje problema u biohemiji. Godine 1937. objavio je rad na temu razdvajanja serumskih proteina znatno usavršenom tehnikom elektroforeze (A. Tiselius, Trans Faraday Soc 33 (1937) 524). Sa ekipom saradnika nastavio je da istražuje mogućnosti elektroforetskih razdvajanja i određivanja, za šta je 1948. godine dobio Nobelovu nagradu za hemiju

Kapilarna elektroforeza - osnovni principi i primena

Electrophoresis is a process in which charged species (ions or colloidal particles) are separated based upon differential migration rates in an electrical field. The first sophisticated electrophoresis apparatus was developed by Swedish scientist Arne Tiselius (Nobel Prize for chemistry in 1948). In the subsequent years electrophoresis separations were the backbone of much research by biochemists and molecular biologists. But as classical electrophoresis is slow, labor intensive technique with poor reproducibility, a new technique - capillary electrophoresis was developed in the mid 1980s. Electrophoresis separation is done in capillaries that are usually 25-75 μm wide (small sample volumes are used (1-10 nL)), under electric field which strength can rise up to 700 V/cm without significant system heating. Therefore capillary electrophoresis (CE) is recognized as a powerful analytical separation technique that brings speed, quantitation reproducibility, and automation to the inherently highly resolving but labor intensive methods of electrophoresis. CE has established itself as an important and widely utilized technique for routine analytical separations isolation, and analysis of proteins, polynucleotides, and other biopolymers.Kapilarna elektroforeza je jedna od danas najčešće korišćenih tehnika za razdvajanje supstanci. Efikasnost, brzina i jednostavnost u podešavanju selektivnosti, osnovne su prednosti koje je vrlo često čine odabranom tehnikom odvajanja i određivanja čak i u konkurenciji sa visoko efikasnom tečnom hromatografijom (HPLC). Elektroforeza je, u opštem smislu, metoda razdvajanja naelektrisanih supstanci prema brzinama kretanja u električnom polju. Prvo razdvajanje supstanci na bazi različitih brzina kretanja u električnom polju izvedeno je krajem 20-ih godina XX veka. Švedski hemičar Arne Tiselius (Arne Wilhelm Kaurin Tiselius, 1902-1971) doktorirao je 1930. godine sa tezom "Tehnika pokretnih granica u proučavanju elektroforeze proteina". U godinama koje su sledile Tiselius se bavio istraživanjima pojava difuzije i adsorpcije kod prirodnih zeolita, ali se od 1936. godine vraća razvijanju tehnike elektroforetskih razdvajanja i ispitivanjima mogućnosti upotrebe fizičkih metoda za rešavanje problema u biohemiji. Godine 1937. objavio je rad na temu razdvajanja serumskih proteina znatno usavršenom tehnikom elektroforeze (A. Tiselius, Trans Faraday Soc 33 (1937) 524). Sa ekipom saradnika nastavio je da istražuje mogućnosti elektroforetskih razdvajanja i određivanja, za šta je 1948. godine dobio Nobelovu nagradu za hemiju

Високо селективни водокомпатибилни молекулски обележени полимери за бензофенон-4

Molecularly imprinting technology was applied for preparing selective sorbents for benzophenone-4 (BP4), an organic UV filter used in sun-screens and cosmetics. Several imprinted polymers were prepared by bulk polymerization, using BP4 as template. Combination of stability (mechanical and chemical), selectivity and robustness of the imprinted polymers with BP4 properties resulted in a successful imprinting process (imprinting factors in range 1.05–2.60). The prepared polymers were characterised by infrared spectroscopy, elemental analysis, conductometric titrations and nitrogen physisorption at 77 K. Adsorption capacities and selectivity towards 7 other organic UV filters (benzophenone-3, benzophenone-8, homosalate, butyl methoxydibenzo-ylmethane, ethyl hexyl salicylate, ethyl hexyl p-dimethylamino benzoate and ethyl hexyl p-methoxycinnamate) were determined, proving high adsorption capacity and high selectivity for BP4 binding. The highest adsorption capacity was observed for 4-vinylpyridine/ethylene glycol dimethacrylate co-polymer prepared in dimethyl sulfoxide (1.108 mmol g-1). The imprinted polymer with the highest binding capacity was applied to solid phase extraction of BP4 from aqueous solutions with 98.5 % efficiency.Технологија молекулског обележавања примењена је у синтези селективних сорбената за бензофенон-4 (BP4), органски UV филтер који се користи у кремама за сунчање и другим козметичким производима. Полимери су добијени полимеризацијом у маси, користећи (BP4) као матрицу. Комбинацијом стабилности (механичке и хемијске), селективности и робусности молекулски обележених полимера са својствима BP4 извршено је успешно обележавање (фактор обележавања 1,05–2,60). Карактеризација добијених полимера је извршена применом инфрацрвене спектроскопије, елементалне анализе, кондуктометријских титрација и физисорпције азота на 77 К. Адсорпциони капацицети и селективност испитани су за 7 других органских UV филтера (бензофенон-3, бензофенон-8, хомосалат, бутилметоксидибензоилметан, етилхексил-салицилат, етилхексил-р-диметиламинобензоат и етилхексил-р-метоксицинамат), потврђујући велики адсорпциони капацитет и високу селективност за везивање BP4. Највећи адсорпциони капацитет показао је ко-полимер 4-винилпиридина и дивинилбензена добијен коришћењем диметил-сулфоксида као порогена (1,108 mmol/g). Полимер са највећим капацицетом за везивање BP4 примењен је као сорбент за екстракцију чврстом фазом BP4 из водених раствора са ефикасношћу од 98,5 %

pH-Dependent solubility profile of desipramine hydrochloride

pH-dependent solubility profile of Desipramine hydrochloride (Ds.HCl) was studied using pH-ramp shake flask method. First, the pH value of DsHCl stock solution in 0.15 M phosphate buffer was adjusted to 11.7 in order to minimize supersaturation effect. Then, the pH value in separate samples was adjusted downwards with HCl, to prepare solutions in the pH 1.7-11.7 region. After stirring (6 h) and sedimentation (18 h), PTFE (hydrophobic, pore size 0.22 µm) filters or centrifugation were used for phase separation. Concentration was measured using HPLC with UV/Vis detection. The computer program pDISOL-X was used for data processing and refinement of equilibrium constants. Different techniques were used for solid phase characterization

pH-Dependent solubility profile of desipramine hydrochloride

pH-dependent solubility profile of Desipramine hydrochloride (Ds.HCl) was studied using pH-ramp shake flask method. First, the pH value of DsHCl stock solution in 0.15 M phosphate buffer was adjusted to 11.7 in order to minimize supersaturation effect. Then, the pH value in separate samples was adjusted downwards with HCl, to prepare solutions in the pH 1.7-11.7 region. After stirring (6 h) and sedimentation (18 h), PTFE (hydrophobic, pore size 0.22 µm) filters or centrifugation were used for phase separation. Concentration was measured using HPLC with UV/Vis detection. The computer program pDISOL-X was used for data processing and refinement of equilibrium constants. Different techniques were used for solid phase characterization

Supplementary data for the article: Cakić, N.; Verbić, T. Ž.; Jelić, R. M.; Platas-Iglesias, C.; Angelovski, G. Synthesis and Characterisation of Bismacrocyclic DO3A-Amide Derivatives - An Approach towards Metal-Responsive PARACEST Agents. Dalton Transactions 2016, 45 (15), 6555–6565. https://doi.org/10.1039/c5dt04625d

Supplementary material for: [https://doi.org/10.1039/c5dt04625d]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1911

Highly selective water-compatible molecularly imprinted polymers for benzophenone-4: Scientific paper

Molecularly imprinting technology was applied for preparing selec­tive sorbents for benzophenone-4 (BP4), an organic UV filter used in sun­screens and cosmetics. Several imprinted polymers were prepared by bulk polymerization, using BP4 as template. Combination of stability (mechanical and chemical), selectivity and robustness of the imprinted polymers with BP4 properties resulted in a successful imprinting process (imprinting factors in range 1.05–2.60). The prepared polymers were characterised by infrared spec­tro­scopy, elemental analysis, conductometric titrations and nitrogen physi­sorp­tion at 77 K. Adsorption capacities and selectivity towards 7 other organic UV filters (benzophenone-3, benzophenone-8, homosalate, butyl methoxydi­ben­zo­ylmethane, ethyl hexyl salicylate, ethyl hexyl p-dimethylamino benzoate and ethyl hexyl p-methoxycinnamate) were determined, proving high adsorption capacity and high selectivity for BP4 binding. The highest adsorption capacity was observed for 4-vinylpyridine/ethylene glycol dimethacrylate co-polymer prepared in dimethyl sulfoxide (1.108 mmol g-1). The imprinted polymer with the highest binding capacity was applied to solid phase extraction of BP4 from aqueous solutions with 98.5 % efficiency

Synthesis and characterisation of bismacrocyclic DO3A-amide derivatives – an approach towards metal-responsive PARACEST agents

[Abstract] Three new bismacrocyclic Ln3+ chelates consisting of triamide derivatives of cyclen with glycine, methyl and tert-butyl substituents (L1–3, respectively) linked to an acyclic EGTA-derived calcium chelator were synthesised as potential MRI contrast agents (EGTA – ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid). Eu3+ and Yb3+ complexes of L1–3 were investigated as chemical exchange saturation transfer (CEST) agents. Moderate to minor CEST effects were observed for Eu2L1, Eu2L2 and Yb2L2 complexes in the absence of Ca2+, with negligible changes upon addition of this metal ion. Luminescence steady-state emission and lifetime experiments did not reveal any changes in the coordination environment of the complexes, while the number of inner-sphere water molecules remained constant in the absence and presence of Ca2+. The protonation constants of Eu2L1 and Eu2L2 and stability constants of their complexes with Ca2+, Mg2+ and Zn2+ were determined by means of potentiometric titrations. The results show that the charge of the complex dramatically affects the protonation constants of the EGTA-binding unit. The stability constants of the complexes formed with Ca2+, Mg2+ and Zn2+ are several orders of magnitude lower than those of EGTA. These findings indicate that the nature of Ln3+ chelates and their charge are the main reasons for the observed results and weaker response of these EGTA-derived triamide derivatives compared to their tricarboxylate analogues

Supplementary data for article: Dorkó, Z.; Szakolczai, A.; Verbic, T.; Horvai, G. Binding Capacity of Molecularly Imprinted Polymers and Their Nonimprinted Analogs. Journal of Separation Science 2015, 38 (24), 4240–4247. https://doi.org/10.1002/jssc.201500874

Supporting information for: [https://doi.org/10.1002/jssc.201500874]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1720