scholarly journals Bacterial Succinoglycans: Structure, Physical Properties, and Applications

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 276
Author(s):  
Jae-pil Jeong ◽  
Yohan Kim ◽  
Yiluo Hu ◽  
Seunho Jung

Succinoglycan is a type of bacterial anionic exopolysaccharide produced from Rhizobium, Agrobacterium, and other soil bacteria. The exact structure of succinoglycan depends in part on the type of bacterial strain, and the final production yield also depends on the medium composition, culture conditions, and genotype of each strain. Various bacterial polysaccharides, such as cellulose, xanthan, gellan, and pullulan, that can be mass-produced for biotechnology are being actively studied. However, in the case of succinoglycan, a bacterial polysaccharide, relatively few reports on production strains or chemical and structural characteristics have been published. Physical properties of succinoglycan, a non-Newtonian and shear thinning fluid, have been reported according to the ratio of substituents (pyruvyl, succinyl, acetyl group), molecular weight (Mw), and measurement conditions (concentration, temperature, pH, metal ion, etc.). Due to its unique rheological properties, succinoglycan has been mainly used as a thickener and emulsifier in the cosmetic and food industries. However, in recent reports, succinoglycan and its derivatives have been used as functional biomaterials, e.g., in stimuli-responsive drug delivery systems, therapeutics, and cell culture scaffolds. This suggests a new and expanded application of succinoglycan as promising biomaterials in biomedical fields, such as tissue engineering, regenerative medicine, and pharmaceuticals using drug delivery.

2017 ◽  
Vol 8 (1) ◽  
pp. 127-143 ◽  
Author(s):  
Menglian Wei ◽  
Yongfeng Gao ◽  
Xue Li ◽  
Michael J. Serpe

Responsive polymer-based materials are capable of altering their chemical and/or physical properties upon exposure to external stimuli. This review highlights their use for sensing and biosensing, drug delivery, and artificial muscles/actuators.


Alloy Digest ◽  
1974 ◽  
Vol 23 (4) ◽  

Abstract FERRO-TIC MS-5 is comprised of ultrahard titanium carbide grains cemented by an age-hardenable martensitic stainless steel matrix. Its unique combination of wear, heat and corrosion resistance and toughness make it well suited for abrasion-resistant components in the aerospace, chemical and food industries. Its maximum operating temperature is 850 F. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as creep. It also includes information on corrosion resistance as well as forming, heat treating, machining, and surface treatment. Filing Code: TS-269. Producer or source: Chromalloy Metal Tectonics Company.


Author(s):  
Feng Wu ◽  
Fei Qiu ◽  
Siew Anthony Wai-Keong ◽  
Yong Diao

Background: In recent years, the emergence of stimuli-responsive nanoparticles makes drug delivery more efficient. As an intelligent and effective targeted delivery platform, it can reduce the side effects generated during drug transportation while enhancing the treatment efficacy. The stimuli-responsive nanoparticles can respond to different stimuli at corresponding times and locations to deliver and release their drugs and associated therapeutic effects. Objective: This review aims to inform researchers on the latest advances in the application of dual-stimuli responsive nanoparticles in precise drug delivery, with special attention to their design, drug release properties, and therapeutic effects. Syntheses of nanoparticles with simultaneous or sequential responses to two or more stimuli (pH-redox, pH-light, redoxlight, temperature-magnetic, pH-redox-temperature, redox-enzyme-light, etc.) and the applications of such responsivity properties for drugs control and release have become a hot topic of recent research. Methods: A database of relevant information for the production of this review was sourced, screened and analyzed from Pubmed, Web of Science, SciFinder by searching for the following keywords: “dual-stimuli responsive”, “controlled release”, “cancer therapy”, “synergistic treatment”. Results: Notably, the nanoparticles with dual-stimuli responsive function have an excellent control effect on drug delivery and release, playing a crucial part in the treatment of tumors. They can improve the encapsulation and delivery efficiency of hydrophobic chemotherapy drugs, combine chemo-photothermal therapies, apply imaging function in the diagnosis of tumors and even conduct multi-drugs delivery to overcome multi-drugs resistance (MDR). Conclusion: With the development of smart dual-stimuli responsive nanoparticles, cancer treatment methods will become more diverse and effective. All the stimuli-responsive nanoparticles functionalities exhibited their characteristics individually within the single nanosystem.


2020 ◽  
Vol 13 (4) ◽  
pp. 291-300 ◽  
Author(s):  
Srividya Gorantla ◽  
Tejashree Waghule ◽  
Vamshi Krishna Rapalli ◽  
Prem Prakash Singh ◽  
Sunil Kumar Dubey ◽  
...  

Hydrogels are aqueous gels composed of cross-linked networks of hydrophilic polymers. Stimuli-responsive based hydrogels have gained focus over the past 20 years for treating ophthalmic diseases. Different stimuli-responsive mechanisms are involved in forming polymer hydrogel networks, including change in temperature, pH, ions, and others including light, thrombin, pressure, antigen, and glucose-responsive. Incorporation of nanocarriers with these smart stimuli-responsive drug delivery systems that can extend the duration of action by increasing ocular bioavailability and reducing the dosing frequency. This review will focus on the hydrogel drug delivery systems highlighting the gelling mechanisms and emerging stimuli-responsive hydrogels from preformed gels, nanogels, and the role of advanced 3D printed hydrogels in vision-threatening diseases like age-related macular degeneration and retinitis pigmentosa. It also provides insight into the limitations of hydrogels along with the safety and biocompatibility of the hydrogel drug delivery systems.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 608
Author(s):  
Csilla Bartos ◽  
Patrícia Varga ◽  
Piroska Szabó-Révész ◽  
Rita Ambrus

The absorption of non-steroidal anti-inflammatory drugs (NSAIDs) through the nasal epithelium offers an innovative opportunity in the field of pain therapy. Thanks to the bonding of chitosan to the nasal mucosa and its permeability-enhancing effect, it is an excellent choice to formulate microspheres for the increase of drug bioavailability. The aim of our work includes the preparation of spray-dried cross-linked and non-cross-linked chitosan-based drug delivery systems for intranasal application, the optimization of spray-drying process parameters (inlet air temperature, pump rate), and the composition of samples. Cross-linked products were prepared by using different amounts of sodium tripolyphosphate. On top of these, the micrometric properties, the structural characteristics, the in vitro drug release, and the in vitro permeability of the products were studied. Spray-drying resulted in micronized chitosan particles (2–4 μm) regardless of the process parameters. The meloxicam (MEL)-containing microspheres showed nearly spherical habit, while MEL was present in a molecularly dispersed state. The highest dissolved (>90%) and permeated (~45 µg/cm2) MEL amount was detected from the non-cross-linked sample. Our results indicate that spray-dried MEL-containing chitosan microparticles may be recommended for the development of a novel drug delivery system to decrease acute pain or enhance analgesia by intranasal application.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1135
Author(s):  
Kristin Entzian ◽  
Achim Aigner

Conventional cancer chemotherapies often exhibit insufficient therapeutic outcomes and dose-limiting toxicity. Therefore, there is a need for novel therapeutics and formulations with higher efficacy, improved safety, and more favorable toxicological profiles. This has promoted the development of nanomedicines, including systems for drug delivery, but also for imaging and diagnostics. Nanoparticles loaded with drugs can be designed to overcome several biological barriers to improving efficiency and reducing toxicity. In addition, stimuli-responsive nanocarriers are able to release their payload on demand at the tumor tissue site, preventing premature drug loss. This review focuses on ultrasound-triggered drug delivery by nanocarriers as a versatile, cost-efficient, non-invasive technique for improving tissue specificity and tissue penetration, and for achieving high drug concentrations at their intended site of action. It highlights aspects relevant for ultrasound-mediated drug delivery, including ultrasound parameters and resulting biological effects. Then, concepts in ultrasound-mediated drug delivery are introduced and a comprehensive overview of several types of nanoparticles used for this purpose is given. This includes an in-depth compilation of the literature on the various in vivo ultrasound-responsive drug delivery systems. Finally, toxicological and safety considerations regarding ultrasound-mediated drug delivery with nanocarriers are discussed.


Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3589
Author(s):  
Rui Liu ◽  
Alessandro Poma

Despite the tremendous efforts made in the past decades, severe side/toxic effects and poor bioavailability still represent the main challenges that hinder the clinical translation of drug molecules. This has turned the attention of investigators towards drug delivery vehicles that provide a localized and controlled drug delivery. Molecularly imprinted polymers (MIPs) as novel and versatile drug delivery vehicles have been widely studied in recent years due to the advantages of selective recognition, enhanced drug loading, sustained release, and robustness in harsh conditions. This review highlights the design and development of strategies undertaken for MIPs used as drug delivery vehicles involving different drug delivery mechanisms, such as rate-programmed, stimuli-responsive and active targeting, published during the course of the past five years.


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