In Vitro Transition Temperature Measurement of Phase-Separating Proteins by Microscopy

2020 ◽  
pp. 703-714
Author(s):  
Jack Holland ◽  
Michael D. Crabtree ◽  
Timothy J. Nott
Keyword(s):  
Transition Temperature ◽  
Temperature Measurement

scholarly journals Preparation of a Sustained Release Drug Delivery System for Dexamethasone by a Thermosensitive, In Situ Forming Hydrogel for Use in Differentiation of Dental Pulp

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Elham Khodaverdi ◽  
Fatemeh Kheirandish ◽  
Farnaz Sadat Mirzazadeh Tekie ◽  
Bibi Zahra Khashyarmanesh ◽  
Farzin Hadizadeh ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Delivery System ◽  
In Vitro Release ◽  
In Situ Forming ◽  
Release Study ◽  
Vitro Release

In situ forming delivery systems composed of block copolymers are attracting substantial attention due to their ease of use, biocompatibility, and biodegradability. In this study, the thermoresponsive triblock copolymer PLGA-PEG-PLGA was studied as a dexamethasone delivery system. Dexamethasone, a synthetic glucocorticoid, is used clinically to improve inflammation, pain, and the hyperemesis of chemotherapy, and it is applied experimentally as a differentiation factor in tissue engineering. PLGA-PEG-PLGA was synthesised under microwave irradiation for 5 min. The obtained copolymer was characterised to determine its structure and phase transition temperature. An in vitro release study was conducted for various copolymer structures and drug concentrations. The yield of the reaction and HNMR analysis confirmed the appropriateness of the microwave-assisted method for PLGA-PEG-PLGA synthesis. Phase transition temperature was affected by the drug molecule as well as by the copolymer concentration and structure. An in vitro release study demonstrated that release occurs mainly by diffusion and does not depend on the copolymer structure or dexamethasone concentration.

Temperature measurement within myocardium during in vitro RF catheter ablation

2000 ◽  
Vol 47 (11) ◽  
pp. 1518-1524 ◽  
Author(s):  
Hong Cao ◽  
V.R. Vorperian ◽  
Jang-Zem Tsai ◽  
S. Tungjitkusolmun ◽  
Eung Je Woo ◽  
...  
Keyword(s):  
Catheter Ablation ◽  
Temperature Measurement

scholarly journals Drug-Membrane Interactions Studied in Phospholipid Monolayers Adsorbed on Nonporous Alkylated Microspheres

2007 ◽  
Vol 12 (2) ◽  
pp. 186-202 ◽  
Author(s):  
Viera Lukacova ◽  
Ming Peng ◽  
Gail Fanucci ◽  
Roman Tandlich ◽  
Anne Hinderliter ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Partition Coefficients ◽  
Temperature Pattern ◽  
Drug Candidates ◽  
Phospholipid Monolayers ◽  
Successful Prediction ◽  
Slow Transport

Characterization of interactions with phospholipids is an integral part of the in vitro profiling of drug candidates because of the roles the interactions play in tissue accumulation and passive diffusion. Currently used test systems may inadequately emulate the bilayer core solvation properties (immobilized artificial membranes [IAM]), suffer from potentially slow transport of some chemicals (liposomes in free or immobilized forms), and require a tedious separation (if used for free liposomes). Here the authors introduce a well-defined system overcoming these drawbacks: nonporous octadecylsilica particles coated with a self-assembled phospholipid monolayer. The coating mimics the structure of the headgroup region, as well as the thickness and properties of the hydrocarbon core, more closely than IAM. The monolayer has a similar transition temperature pattern as the corresponding bilayer. The particles can be separated by filtration or a mild centrifugation. The partitioning equilibria of 81 tested chemicals were dissected into the headgroup and core contributions, the latter using the alkane/water partition coefficients. The deconvolution allowed a successful prediction of the bilayer/water partition coefficients with the standard deviation of 0.26 log units. The plate-friendly assay is suitable for high-throughput profiling of drug candidates without sacrificing the quality of analysis or details of the drug-phospholipid interactions.

scholarly journals Microencapsulation and Characterization of Natural Polyphenols from PHF Extract

2018 ◽  
Author(s):  
Syed Ammar Hussain ◽  
Ahsan Hameed ◽  
Yusuf Nazir ◽  
Tahira Naz ◽  
Yang Wu ◽  
...  
Keyword(s):  
Particle Size ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Beta Carotene ◽  
Alpha Amylase ◽  
Total Phenolic ◽  
Freeze Dried ◽  
Alpha Glucosidase

Microencapsulation of polyherbal formulation (PHF) extract was carried out by freeze drying method, by employing gum arabic (GA), gelatin (GE), and maltodextrin (MD) with their designated different combinations as encapsulating wall materials. Antioxidant components (i.e total phenolic contents (TPC),Total flavonoids contents (TFC), and total condensed contents (TCT)), antioxidant activity (i.e. DPPH, β-carotene & ABTS+ assays), moisture contents, water activity (aw), solubility, hygroscopicity, glass transition temperature (Tg), particle size, morphology, in vitro alpha-amylase and alpha-glucosidase inhibition and bioavailability ratios of the powders were investigated. Amongst all encapsulated products, TB (5% GA and 5% MD) and TC (10% GA) has proven to be the best treatments with respect to the highest preservation of antioxidant components and their antioxidant potential by DPPH and β-carotene assays and noteworthy for an ABTS+ assays, in addition, the aforesaid treatments also demonstrated lower moisture content, aw, particle size and higher solubility, hygroscopicity and glass transition temperature (Tg). All freeze dried samples showed irregular (asymmetrical) microcrystalline structures. Furthermore, TB and TC also illustrated the highest in vitro anti-diabetic potential due to great potency for inhibiting alpha-amylase and alpha-glucosidase activities. In the perspective of bioavailability, TA, TB and TC demonstrated the excellent bioavailability ratios (%).Futhermore, the phytochemo-profiling of ethanolic extract of PHF was also revealed to find out the bioactive compounds.

scholarly journals A Portable Microscale Cell Culture System with Indirect Temperature Control

2018 ◽  
Vol 23 (6) ◽  
pp. 566-579 ◽  
Author(s):  
Antti-Juhana Mäki ◽  
Jarmo Verho ◽  
Joose Kreutzer ◽  
Tomi Ryynänen ◽  
Dhanesh Rajan ◽  
...  
Keyword(s):  
Cell Culture ◽  
Temperature Measurement ◽  
Temperature Control ◽  
Control Method ◽  
Environmental Parameters ◽  
Heating System ◽  
Indirect Measurement ◽  
Precise Control

A physiologically relevant environment is essential for successful long-term cell culturing in vitro. Precise control of temperature, one of the most crucial environmental parameters in cell cultures, increases the fidelity and repeatability of the experiments. Unfortunately, direct temperature measurement can interfere with the cultures or prevent imaging of the cells. Furthermore, the assessment of dynamic temperature variations in the cell culture area is challenging with the methods traditionally used for measuring temperature in cell culture systems. To overcome these challenges, we integrated a microscale cell culture environment together with live-cell imaging and a precise local temperature control that is based on an indirect measurement. The control method uses a remote temperature measurement and a mathematical model for estimating temperature at the desired area. The system maintained the temperature at 37±0.3 °C for more than 4 days. We also showed that the system precisely controls the culture temperature during temperature transients and compensates for the disturbance when changing the cell cultivation medium, and presented the portability of the heating system. Finally, we demonstrated a successful long-term culturing of human induced stem cell–derived beating cardiomyocytes, and analyzed their beating rates at different temperatures.

Sign in / Sign up

Export Citation Format

Share Document