scholarly journals Thermoresponsive Polymers for Biomedical Applications

Polymers ◽  
2011 ◽  
Vol 3 (3) ◽  
pp. 1215-1242 ◽  
Author(s):  
Mark A. Ward ◽  
Theoni K. Georgiou
Keyword(s):  
Biomedical Applications ◽  
Thermoresponsive Polymers

scholarly journals Chitosan-Based Biocompatible Copolymers for Thermoresponsive Drug Delivery Systems: On the Development of a Standardization System

Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1876
Author(s):  
Lorenzo Marsili ◽  
Michele Dal Bo ◽  
Federico Berti ◽  
Giuseppe Toffoli
Keyword(s):  
Drug Delivery ◽  
Biomedical Applications ◽  
Biological Tissues ◽  
Special Focus ◽  
Thermoresponsive Polymers ◽  
Basic Principles ◽  
Natural Polysaccharide ◽  
Non Covalent Interactions ◽  
Covalent Interactions ◽  
Or Applications

Chitosan is a natural polysaccharide that is considered to be biocompatible, biodegradable and non-toxic. The polymer has been used in drug delivery applications for its positive charge, which allows for adhesion with and recognition of biological tissues via non-covalent interactions. In recent times, chitosan has been used for the preparation of graft copolymers with thermoresponsive polymers such as poly-N-vinylcaprolactam (PNVCL) and poly-N-isopropylamide (PNIPAM), allowing the combination of the biodegradability of the natural polymer with the ability to respond to changes in temperature. Due to the growing interest in the utilization of thermoresponsive polymers in the biological context, it is necessary to increase the knowledge of the key principles of thermoresponsivity in order to obtain comparable results between different studies or applications. In the present review, we provide an overview of the basic principles of thermoresponsivity, as well as a description of the main polysaccharides and thermoresponsive materials, with a special focus on chitosan and poly-N-Vinyl caprolactam (PNVCL) and their biomedical applications.

scholarly journals Probing the causes of thermal hysteresis using tunable Nagg micelles with linear and brush-like thermoresponsive coronas

2017 ◽  
Vol 8 (1) ◽  
pp. 233-244 ◽  
Author(s):  
L. D. Blackman ◽  
M. I. Gibson ◽  
R. K. O'Reilly
Keyword(s):  
Aqueous Solution ◽  
Biomedical Applications ◽  
Thermal Hysteresis ◽  
Thermoresponsive Polymers ◽  
Self Assembled ◽  
Switchable Materials

Self-assembled thermoresponsive polymers in aqueous solution have great potential as smart, switchable materials for use in biomedical applications.

scholarly journals Novel thermoresponsive polymer outperforming Pluronic® F127

2020 ◽  
Author(s):  
Anna Constantinou ◽  
Valeria Nele ◽  
James Doutch ◽  
Roman Moiseev ◽  
Vitaliy Khutoryanskiy ◽  
...  
Keyword(s):  
Self Assembly ◽  
Biomedical Applications ◽  
Ex Vivo ◽  
Structural Characteristics ◽  
Thermoresponsive Polymer ◽  
Scanning Calorimetry ◽  
Thermoresponsive Polymers ◽  
Crosslinked Networks ◽  
Gelation Concentration ◽  
Physically Crosslinked

Abstract Thermoresponsive polymers featuring the appropriate combination of structural characteristics, i.e. architecture, composition, and molar mass (MM), can form physically crosslinked networks in a solvent upon changes in temperature. This fascinating class of polymers finds utility in various sectors such as formulation science and tissue engineering. Here, we report a novel thermoresponsive triblock terpolymer which out-performs the most commonly used and commercially available thermoresponsive polymer, Poloxamer P407 (also known as Pluronic® F127) in terms of gelation concentration. Specifically, the in-house synthesised polymer forms gels at lower concentrations that is an advantage in biomedical applications. To elucidate the differences in their macroscale gelling behaviour, we investigate their micellization via differential scanning calorimetry, and their nanoscale self-assembly behaviour in detail by means of small-angle neutron scattering by simultaneously recording their rheological properties (Rheo-SANS). Two different gelation mechanisms for the two polymers are revealed and proposed. Ex vivo gelation study upon intracameral injections demonstrated excellent potential for its application to improve drug residence in the eye.

scholarly journals Recent Advances in Thermoresponsive OEGylated Poly(amino acid)s

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1813
Author(s):  
Chao Geng ◽  
Shixue Wang ◽  
Hongda Wang
Keyword(s):  
Amino Acid ◽  
Ethylene Glycol ◽  
Biomedical Applications ◽  
Synthesis Method ◽  
Structure Study ◽  
Thermoresponsive Polymers ◽  
Design Synthesis ◽  
Behavior Study ◽  
Potential Applications ◽  
Stimuli Response

Thermoresponsive polymers have been widely studied in the past decades due to their potential applications in biomedicine, nanotechnology, and so on. As is known, poly(N-isopropylacrylamide) (PNIPAM) and poly(oligo(ethylene glycol)methacrylates) (POEGMAs) are the most popular thermoresponsive polymers, and have been studied extensively. However, more advanced thermoresponsive polymers with excellent biocompatibility, biodegradability, and bioactivity also need to be developed for biomedical applications. OEGylated poly(amino acid)s are a kind of novel polymer which are synthesized by attaching one or multiple oligo(ethylene glycol) (OEG) chains to poly(amino acid) (PAA).These polymers combine the great solubility of OEG, and the excellent biocompatibility, biodegradability and well defined secondary structures of PAA. These advantages allow them to have great application prospects in the field of biomedicine. Therefore, the study of OEGylated poly(amino acid)s has attracted more attention recently. In this review, we summarized the development of thermoresponsive OEGylated poly(amino acid)s in recent years, including the synthesis method (such as ring-opening polymerization, post-polymerization modification, and Ugi reaction), stimuli-response behavior study, and secondary structure study. We hope that this periodical summary will be more conducive to design, synthesis and application of OEGylated poly(amino acid)s in the future.

scholarly journals Effect of Dexamethasone on Thermoresponsive Behavior of Poly(2-Oxazoline) Diblock Copolymers

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1357
Author(s):  
Monika Majerčíková ◽  
Peter Nádaždy ◽  
Dušan Chorvát ◽  
Leonid Satrapinskyy ◽  
Helena Valentová ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Diblock Copolymers ◽  
Polarized Light ◽  
Drug Carriers ◽  
Thermoresponsive Polymers ◽  
X Ray Scattering ◽  
Small Series ◽  
Cloud Point Temperature ◽  
Crystalline Nature ◽  
Chain Lengths

Thermoresponsive polymers play an important role in designing drug delivery systems for biomedical applications. In this contribution, the effect of encapsulated hydrophobic drug dexamethasone on thermoresponsive behavior of diblock copolymers was studied. A small series of diblock copoly(2-oxazoline)s was prepared by combining thermoresponsive 2-n-propyl-2-oxazoline (nPrOx) and hydrophilic 2-methyl-2-oxazoline (MeOx) in two ratios and two polymer chain lengths. The addition of dexamethasone affected the thermoresponsive behavior of one of the copolymers, nPrOx20-MeOx180, in the aqueous medium by shifting the cloud point temperature to lower values. In addition, the formation of microparticles containing dexamethasone was observed during the heating of the samples. The morphology and number of microparticles were affected by the structure and concentration of copolymer, the drug concentration, and the temperature. The crystalline nature of formed microparticles was confirmed by polarized light microscopy, confocal Raman microscopy, and wide-angle X-ray scattering. The results demonstrate the importance of studying drug/polymer interactions for the future development of thermoresponsive drug carriers.

scholarly journals Hydrogen Bonds in Blends of Poly(N-isopropylacrylamide), Poly(N-ethylacrylamide) Homopolymers, and Carboxymethyl Cellulose

2021 ◽  
Vol 5 (9) ◽  
pp. 240
Author(s):  
Alberto García-Peñas ◽  
Weijun Liang ◽  
Saud Hashmi ◽  
Gaurav Sharma ◽  
Mohammad Reza Saeb ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Carboxymethyl Cellulose ◽  
Biomedical Applications ◽  
Thermoresponsive Polymers ◽  
Molecular Features ◽  
Physical Crosslinking ◽  
Critical Solution Temperatures

Recently, it was reported that the physical crosslinking exhibited by some biopolymers could provide multiple benefits to biomedical applications. In particular, grafting thermoresponsive polymers onto biopolymers may enhance the degradability or offer other features, as thermothickening behavior. Thus, different interactions will affect the different hydrogen bonds and interactions from the physical crosslinking of carboxymethyl cellulose, the lower critical solution temperatures (LCSTs), and the presence of the ions. This work focuses on the study of blends composed of poly(N-isopropylacrylamide), poly(N-ethylacrylamide), and carboxymethyl cellulose in water and water/methanol. The molecular features, thermoresponsive behavior, and gelation phenomena are deeply studied. The ratio defined by both homopolymers will alter the final properties and the gelation of the final structures, showing that the presence of the hydrophilic groups modifies the number and contributions of the diverse hydrogen bonds.

Applications of Scanning Microscopy in Biomedical Research

1968 ◽  
Vol 26 ◽  
pp. 354-355
Author(s):  
T. L. Hayes
Keyword(s):  
Information Content ◽  
Biomedical Research ◽  
Biomedical Applications ◽  
Three Dimensional ◽  
Dental Enamel ◽  
Resolving Power ◽  
Whole Mount ◽  
Two Parameters ◽  
Content Information ◽  
Sectioned Tissue

Biomedical applications of the scanning electron microscope (SEM) have increased in number quite rapidly over the last several years. Studies have been made of cells, whole mount tissue, sectioned tissue, particles, human chromosomes, microorganisms, dental enamel and skeletal material. Many of the advantages of using this instrument for such investigations come from its ability to produce images that are high in information content. Information about the chemical make-up of the specimen, its electrical properties and its three dimensional architecture all may be represented in such images. Since the biological system is distinctive in its chemistry and often spatially scaled to the resolving power of the SEM, these images are particularly useful in biomedical research.In any form of microscopy there are two parameters that together determine the usefulness of the image. One parameter is the size of the volume being studied or resolving power of the instrument and the other is the amount of information about this volume that is displayed in the image. Both parameters are important in describing the performance of a microscope. The light microscope image, for example, is rich in information content (chemical, spatial, living specimen, etc.) but is very limited in resolving power.

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