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Applied Microbiology and Biotechnology Nov 2021As the energy demand is escalating tremendously and crude oil being the primary energy source for at least the next two decades, the production of crude oil should be... (Review)
Review
As the energy demand is escalating tremendously and crude oil being the primary energy source for at least the next two decades, the production of crude oil should be enhanced to meet the global energy needs. This can be achieved by either exploration of new oil fields for crude oil extraction or employing enhanced oil recovery (EOR) technology to recover the residual oil from existing marginal oil fields. The former method requires more capital investment and time; therefore, this review focuses on the latter. In general, the abandoned oil fields still have 50% of crude left which is unrecovered due to lack of technology. Hence, EOR came into existence after the conventional methods of recovery (primary and secondary recovery) were found to be inefficient and less economical. Nineteen percent of the EOR projects are based upon cEOR methods worldwide, of which more than 80% of projects use economically feasible polymer flooding process for oil recovery. Both synthetic and naturally derived polymers have been used widely for this purpose; however, many recent studies have shown the lower stability of synthetic polymers under extreme reservoir conditions of high salinity and temperature. Additionally, naturally derived polymers face microbial degradation as the major limitation. Therefore, a number of novel polymers are currently studied for their suitability as an efficient EOR polymer. Latest findings have also revealed that biopolymers play an important role in wettability alteration, pore evolution by bioplugging, and reducing fingering effect. Injection of biopolymers can also lead to the selective plugging of thief zones which redirects water flood to the inaccessible oil pores. Therefore, the current study focuses on such principle and mechanism of polymer flooding along with the reservoir and field characteristics which affects the polymer flooding. It also discusses the scope of biopolymer along with the screening criteria for use of novel polymers and strategies to overcome the problems during polymer flooding. KEY POINTS: • Discussion of macroscopic and microscopic mechanisms of polymer flooding. • Screening criteria of polymers prior to flooding are essential. • Biopolymers are eco-friendly and are applicable for a wide range of reservoir conditions.
Topics: Biopolymers; Oil and Gas Fields; Patient Selection; Petroleum; Polymers
PubMed: 34609524
DOI: 10.1007/s00253-021-11618-y -
Advanced Drug Delivery Reviews Dec 2022Silk-Elastinlike Protein-Based Polymers (SELPs) can form thermoresponsive hydrogels that allow for the generation of in-situ drug delivery matrices. They are produced by... (Review)
Review
Silk-Elastinlike Protein-Based Polymers (SELPs) can form thermoresponsive hydrogels that allow for the generation of in-situ drug delivery matrices. They are produced by recombinant techniques, enabling exact control of monomer sequence and polymer length. In aqueous solutions SELP strands form physical crosslinks as a function of temperature increase without the addition of crosslinking agents. Gelation kinetics, modulus of elasticity, pore size, drug release, biorecognition, and biodegradation of SELP hydrogels can be controlled by placement of amino acid residues at strategic locations in the polymer backbone. SELP hydrogels have been investigated for delivery of a variety of bioactive agents including small molecular weight drugs and fluorescent probes, oligomers of glycosaminoglycans, polymeric macromolecules, proteins, plasmid DNA, and viral gene delivery systems. In this review we provide a background for use of SELPs in matrix-mediated delivery and summarize recent investigations of SELP hydrogels for controlled delivery of bioactive agents as well as their use as liquid embolics.
Topics: Humans; Silk; Hydrogels; Elastin; Amino Acid Sequence; Polymers
PubMed: 36306893
DOI: 10.1016/j.addr.2022.114579 -
Biomedicine & Pharmacotherapy =... May 2021Immunotherapy that boosts the body's immune system to treat local and distant metastatic tumors has offered a new treatment option for cancer. However, cancer... (Review)
Review
Immunotherapy that boosts the body's immune system to treat local and distant metastatic tumors has offered a new treatment option for cancer. However, cancer immunotherapy via systemic administration of immunotherapeutic agents often has two major issues of limited immune responses and potential immune-related adverse events in the clinic. Hydrogels, a class of three-dimensional network biomaterials with unique porous structures can achieve local delivery of drugs into tumors to trigger the antitumor immunity, resulting in amplified immunotherapy at lower dosages. In this review, we summarize the recent development of polymer-based hydrogels as drug release systems for local delivery of various immunotherapeutic agents for cancer immunotherapy. The constructions of polymer-based hydrogels and their local delivery of various drugs in tumors to achieve sole immunotherapy, and chemotherapy-, and phototherapy-combinational immunotherapy are introduced. Furthermore, a brief conclusion is given and existing challenges and further perspectives of polymer-based hydrogels for cancer immunotherapy are discussed.
Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Drug Delivery Systems; Drug Liberation; Humans; Hydrogels; Immunotherapy; Neoplasms; Phototherapy; Polymers
PubMed: 33571834
DOI: 10.1016/j.biopha.2021.111333 -
Angewandte Chemie (International Ed. in... Oct 2022Creation of new two-dimensional (2D) architectures has attracted significant attention in the field of self-assembly for structural diversity and new functionalization....
Creation of new two-dimensional (2D) architectures has attracted significant attention in the field of self-assembly for structural diversity and new functionalization. Although numerous 2D polymer nanosheets have been reported, 2D nanosheets with tubular channels have been unexplored. Herein, we describe a new strategy for the fabrication of stimulus-responsive conjugated polymer 2D nanosheets with hollow cavities. Amphiphilic macrocyclic diacetylenes self-assembled in an aqueous solution in a columnar manner to afford bilayered 2D nanosheets with intrinsically tubular nanochannels. UV-induced polymerization resulted in the generation of blue-colored tubular conjugated polydiacetylene 2D nanosheets. Immobilization of gold nanoparticles, fluorescence labeling with FRET phenomenon and colorimetric DNA sensing were demonstrated with these new 2D nanosheets. In addition, the free NH containing polymerized 2D nanosheet was utilized for conductivity behavior and grafting on graphene oxide (GO).
Topics: Gold; Stimuli Responsive Polymers; Metal Nanoparticles; Polymers; Colorimetry
PubMed: 36045485
DOI: 10.1002/anie.202211465 -
Physical Biology Jun 2022Polymers are important components of the complex fluid environment for microorganisms. The mechanical effects on bacterial motile behavior due to the viscous or...
Polymers are important components of the complex fluid environment for microorganisms. The mechanical effects on bacterial motile behavior due to the viscous or viscoelastic properties of polymers were extensively studied, whereas possible chemical effects on bacterial motility through bacterial chemoreception of the polymers were unclear. Here we studied the chemotactic response ofto polymeric solutions by combining the bead assay and FRET measurements. We found that the wild-typestrain exhibited an attractant response to widely used polymers such as Ficoll 400, polyethylene glycol (PEG) 20000 and polyvinyl pyrrolidone (PVP) 360000, and the response amplitude from chemoreception was much larger than that from the load-dependence of motor switching due to viscosity change. The chemotactic response depended on the type of receptors and the chain length of the polymers. Our findings here provided important new ingredients for further studies of bacterial motile behavior in complex fluids.
Topics: Polymers; Povidone; Viscosity
PubMed: 35545074
DOI: 10.1088/1478-3975/ac6eb1 -
Proceedings of the National Academy of... Jun 2023The consistent rise of plastic pollution has stimulated interest in the development of biodegradable plastics. However, the study of polymer biodegradation has...
The consistent rise of plastic pollution has stimulated interest in the development of biodegradable plastics. However, the study of polymer biodegradation has historically been limited to a small number of polymers due to costly and slow standard methods for measuring degradation, slowing new material innovation. High-throughput polymer synthesis and a high-throughput polymer biodegradation method are developed and applied to generate a biodegradation dataset for 642 chemically distinct polyesters and polycarbonates. The biodegradation assay was based on the clear-zone technique, using automation to optically observe the degradation of suspended polymer particles under the action of a single bacterial colony. Biodegradability was found to depend strongly on aliphatic repeat unit length, with chains less than 15 carbons and short side chains improving biodegradability. Aromatic backbone groups were generally detrimental to biodegradability; however, ortho- and para-substituted benzene rings in the backbone were more likely to be degradable than metasubstituted rings. Additionally, backbone ether groups improved biodegradability. While other heteroatoms did not show a clear improvement in biodegradability, they did demonstrate increases in biodegradation rates. Machine learning (ML) models were leveraged to predict biodegradability on this large dataset with accuracies over 82% using only chemical structure descriptors.
Topics: Polyesters; Plastics; Polymers; Biodegradable Plastics; Biodegradation, Environmental; Research Design
PubMed: 37252959
DOI: 10.1073/pnas.2220021120 -
Molecules (Basel, Switzerland) Sep 2020Cancer represents one of the most dangerous diseases, with 1.8 million deaths worldwide. Despite remarkable advances in conventional therapies, these treatments are not... (Review)
Review
Cancer represents one of the most dangerous diseases, with 1.8 million deaths worldwide. Despite remarkable advances in conventional therapies, these treatments are not effective to completely eradicate cancer. Nanotechnology offers potential cancer treatment based on formulations of several nanoparticles (NPs). Liposomes and polymeric nanoparticle are the most investigated and effective drug delivery systems (DDS) for cancer treatment. Liposomes represent potential DDS due to their distinct properties, including high-drug entrapment efficacy, biocompatibility, low cost, and scalability. However, their use is restricted by susceptibility to lipid peroxidation, instability, burst release of drugs, and the limited surface modification. Similarly, polymeric nanoparticles show several chemical modifications with polymers, good stability, and controlled release, but their drawbacks for biological applications include limited drug loading, polymer toxicity, and difficulties in scaling up. Therefore, polymeric nanoparticles and liposomes are combined to form polymer-lipid hybrid nanoparticles (PLHNPs), with the positive attributes of both components such as high biocompatibility and stability, improved drug payload, controlled drug release, longer circulation time, and superior in vivo efficacy. In this review, we have focused on the prominent strategies used to develop tumor targeting PLHNPs and discuss their advantages and unique properties contributing to an ideal DDS.
Topics: Animals; Humans; Lipids; Molecular Targeted Therapy; Nanoparticles; Neoplasms; Polymers
PubMed: 32977707
DOI: 10.3390/molecules25194377 -
Molecules (Basel, Switzerland) Oct 2020In recent years, molecularly imprinted polymers (MIPs) have become an excellent solution to the selective and sensitive determination of target molecules in complex... (Review)
Review
In recent years, molecularly imprinted polymers (MIPs) have become an excellent solution to the selective and sensitive determination of target molecules in complex matrices where other similar and relative structural compounds could coexist. Although MIPs show the inherent properties of the polymers, including stability, robustness, and easy/cheap synthesis, some of their characteristics can be enhanced, or new functionalities can be obtained when nanoparticles are incorporated in their polymeric structure. The great variety of nanoparticles available significantly increase the possibility of finding the adequate design of nanostructured MIP for each analytical problem. Moreover, different structures (i.e., monolithic solids or MIPs micro/nanoparticles) can be produced depending on the used synthesis approach. This review aims to summarize and describe the most recent and innovative strategies since 2015, based on the combination of MIPs with nanoparticles. The role of the nanoparticles in the polymerization, as well as in the imprinting and adsorption efficiency, is also discussed through the review.
Topics: Adsorption; Molecular Imprinting; Molecularly Imprinted Polymers; Nanoparticles; Polymerization; Polymers
PubMed: 33076552
DOI: 10.3390/molecules25204740 -
International Journal of Molecular... Dec 2023Chitosan is a polymer of natural origins that possesses many favourable properties [...].
Chitosan is a polymer of natural origins that possesses many favourable properties [...].
Topics: Chitosan; Polymers
PubMed: 38203726
DOI: 10.3390/ijms25010554 -
Pharmaceutical Research Sep 2023Amorphous solid dispersions (ASDs), wherein a drug is molecularly dispersed in a polymer, can improve physical stability and oral bioavailability of poorly soluble...
OBJECTIVES
Amorphous solid dispersions (ASDs), wherein a drug is molecularly dispersed in a polymer, can improve physical stability and oral bioavailability of poorly soluble drugs. Risk of drug crystallization is usually averted using high polymer concentrations. However, we demonstrated recently that the overlap concentration, C*, of polymer in drug melt is the minimum polymer concentration required to maintain drug in the amorphous state following rapid quench. This conclusion was confirmed for several drugs mixed with poly(vinylpyrrolidone) (PVP). Here we assess the solid-state stability of ASDs formulated with a variety of polymers and drugs and at various polymer concentrations (C) and molecular weights (MWs). We further test the hypothesis that degree of drug crystallization decreases with increasing C/C* and vanishes when C>C*, where C* depends on polymer MW and strength of drug-polymer interaction.
METHODS
We test our hypothesis with ASDs consisting of ketoconazole admixed with polyacrylic acid, polymethacrylic acid and poly (methacrylic acid-co-ethyl acrylate); and felodipine admixed with PVP and poly (vinylpyrrolidone-co-vinyl acetate). Values of C* for polymers in molten drug are rheologically determined. Crystallization behavior is assessed by measuring enthalpy of fusion, ΔH and by X-ray diffraction.
RESULTS
We confirm that ΔH/ΔH = f(C/C∗), and essentially no crystallization occurs when C>C*.
CONCLUSIONS
Our findings will aid researchers in designing or selecting appropriate polymers to inhibit crystallization of poorly soluble drugs. This research also suggests that C* as determined by rheology can be used to compare drug-polymer interactions for similar molecular weight polymers.
Topics: Polymers; Crystallization; Felodipine; Ketoconazole; Rheology; Solubility; Povidone
PubMed: 37552386
DOI: 10.1007/s11095-023-03570-5