Amphiphilic diblock copolymers inhibit the formation of encrustation on the surface of biodegradable ureteral stents in vitro and in vivo

2021 ◽  
Vol 610 ◽  
pp. 125667
Author(s):  
Yu Zhang ◽  
Jin Qi ◽  
Hechun Chen ◽  
Chengdong Xiong
Keyword(s):  
Diblock Copolymers ◽  
Ureteral Stents ◽  
Amphiphilic Diblock Copolymers

scholarly journals Self-restoring polymer brushes under tribological stress and the biomedical applications

MRS Advances ◽  
2016 ◽  
Vol 1 (27) ◽  
pp. 1971-1976
Author(s):  
Troels Røn ◽  
Irakli Javakhishvili ◽  
Søren Hvilsted ◽  
Katja Jankova ◽  
Seunghwan Lee
Keyword(s):  
Polymer Brushes ◽  
Diblock Copolymers ◽  
Polymer Chains ◽  
Aqueous Environment ◽  
Pdms Film ◽  
Pdms Surface ◽  
Tribological Application ◽  
Optimal Functions ◽  
Amphiphilic Diblock Copolymers

ABSTRACTFor biological and mechanical systems involving moving parts, surface slipperiness is often a critical attribute for their optimal functions. Surface grafting with hydrophilic polymers is a powerful means to render materials slippery in aqueous environment. In “inverted grafting-to approach”, the hydrophilic polymer chains of amphiphilic diblock copolymers dispersed within a poly(dimethylsiloxane) (PDMS) network are selectively segregated upon exposure to aqueous solution. This allows formation of extremely stable brush-like polymer layers. Tribological application of inverted grafting-to approach was successfully demonstrated with PDMS-block-poly(acrylic acid) (PDMS-b-PAA) dispersed within thin PDMS films on PDMS blocks by showing friction coefficients (µ) of ca 10-2 to 10-3, depending on the load, pH and buffer salinity in the absence of other external re-supply of PAA chains. Further manipulations of the thin PDMS film incorporating PDMS-b-PAA to optimize the tribological properties are presented. Lastly, first trials to employ PAA-grafted PDMS surface to generate in-vitro mucosae model are also presented and discussed.

Microbial Adhesion and Biofilm Formation on Ureteral Stents in Vitro and in Vivo

1992 ◽  
Vol 148 (5 Part 1) ◽  
pp. 1592-1594 ◽  
Author(s):  
Gregor Reid ◽  
John D. Denstedt ◽  
Yun Suk Kang ◽  
Dominique Lam ◽  
Carolyn Nause
Keyword(s):  
Biofilm Formation ◽  
Ureteral Stents ◽  
Microbial Adhesion

scholarly journals Doxorubicin-Loaded Mixed Micelles Using Degradable Graft and Diblock Copolymers to Enhance Anticancer Sensitivity

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3816
Author(s):  
Yi-Chun Chen ◽  
Chang-Jung Chang ◽  
Ging-Ho Hsiue ◽  
Yi-Ting Chiang
Keyword(s):  
Cancer Cells ◽  
Graft Copolymer ◽  
Diblock Copolymers ◽  
Mixed Micelles ◽  
High Rate ◽  
Micellar System ◽  
Hydroxypropyl Methacrylamide ◽  
Tumor Accumulation

In this study, a graft copolymer, poly(N-(2-hydroxypropyl) methacrylamide dilactate)-co-(N-(2-hydroxypropyl) methacrylamide-co-histidine)-graft-poly(d,l-lactide), and a diblock copolymer, methoxy poly(ethylene glycol)-b-poly(d,l-lactide), were assembled into a mixed micellar system to encapsulate the anticancer drug doxorubicin (Dox). This mixed micellar system possesses the hydrophobic lactide segment of both copolymers, which reinforces its stability in physiological milieus; the histidine molecules appended on the graft copolymer provide the desired pH-responsive behavior to release Dox during internalization in cancer cells. The results demonstrate that the two copolymers were successfully prepared, and their ratios in the mixed micelles were optimized on the basis of the results of the stability tests. Under acidic conditions, the mixed micelles swell and are able to release their payloads. Therefore, the in vitro results indicate that the Dox in the mixed micelles is released effectively in response to the environmental pH of the mimetic internalization process, increasing cancer cells’ sensitivity toward Dox. The mixed micelles display low cytotoxicity due to the degradability of the polymers. The in vivo images show that the high stability of the mixed micelles ensures a high tumor accumulation. This selective tumor accumulation results in an excellent inhibition of in vivo tumor growth and a high rate of apoptosis in cancerous tissues, with low toxicity. This highly stable, mixed micellar system with a pH-dependent drug release, which enables the precise delivery of drugs to the tumor lesions, is feasible to employ clinically in cancer therapy.

Hybrid Type of Tissue Engineered Biodisc Using Annulus Fibrosus Seeded PLGA Scaffold and Nucleus Pulposus Seeded MPEG-PCL Hydrogel: Preliminary Study

2007 ◽  
Vol 342-343 ◽  
pp. 173-176 ◽  
Author(s):  
Youn Kyung Ko ◽  
Soon Hee Kim ◽  
Hyun Jung Ha ◽  
Sun Jung Yoon ◽  
John M. Rhee ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Annulus Fibrosus ◽  
Diblock Copolymers ◽  
Cell Function ◽  
Plga Scaffold ◽  
Salt Leaching ◽  
Hybrid Type ◽  
Poly Caprolactone

Recently, it has been studied tissue engineered technique as novel approaches for treatment of the degenerative intervertebral disc (IVD). We designed the hybrid type of IVD mimicked scaffolds with poly(lactide-co-glycolide) (PLGA) and methoxypoly(ethyleneglycol)- poly(-caprolactone) (MPEG-PCL) diblock copolymers in order to application for the tissue engineered IVD. The MPEG-PCL solutions formed a gel-to-sol phase transitions as the temperature was increasesd. MPEG-PCL diblock copolymers were prepared by ring opening polymerization, and then nucleus pulposus (NP) cell was impregnated. Also, in order to restore annulus fibrosus (AF), we fabricated PLGA scaffold by solvent casting/salt leaching method. We confirmed disc cell function in manufactured scaffold through MTT assay in vitro and gross morphology and special staining in vivo for the possibility of the application of tissue engineering techniques.

scholarly journals In Vivo and In Vitro Elution of Analgesics from Multilayered Poly(D,L)-lactide-co-glycolide Nanofibers Incorporated Ureteral Stents

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Yi-Chia Lin ◽  
Kuo-Sheng Liu ◽  
Demei Lee ◽  
Min-Jhan Li ◽  
Shih-Jung Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Local Drug Delivery ◽  
Ureteral Stents ◽  
Water Contact ◽  
Elution Behavior ◽  
Behavior Characteristics ◽  
Contact Angle Analysis ◽  
Scanning Electron

We develop novel analgesic-eluting nanofiber-incorporated ureteral stents that offer sustained release of lidocaine and ketorolac for local drug delivery. Lidocaine and poly(D,L)-lactide-co-glycolide (PLGA) were dissolved in hexafluoroisopropanol and were electrospun into nonwoven nanofibers onto the surface of ureteral stents. This was followed by electrospinning of another layer of PLGA nanofibers containing ketorolac. Electrospun drug-loaded nanofibers were then characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and water contact angle analysis. In addition, the elution behavior characteristics of the analgesics, both in vivo and in vitro, from the nanofiber-incorporated stents were evaluated. Experimental results indicate that the analgesic-eluting ureteral stents could liberate high strengths of analgesics in vitro and in vivo for at least 50 and 30 days, respectively. The analgesic-eluting nanofiber-incorporated ureteral stents are potentially applicable for alleviating the discomfort associated with stent implant.

A new hydrophilic biodegradable ureteral stent restrain encrustation both in vitro and in vivo

2020 ◽  
Vol 35 (6) ◽  
pp. 720-731
Author(s):  
Yu Zhang ◽  
Jian He ◽  
Hechun Chen ◽  
Chengdong Xiong
Keyword(s):  
Lower Amount ◽  
Biodegradable Material ◽  
Ureteral Stents ◽  
Pathological Analysis ◽  
Long Time ◽  
New Type ◽  
Artificial Urine ◽  
Urological Diseases

Ureteral stents have been widely used as biomedical devices to treat some urological diseases for several decades. However, the encrustation complications hamper the long-time clinical use of the ureteral stents. In this work, a new type of biodegradable material for the ureteral stents, methoxypoly(ethylene glycol)-block-poly(L-lactide-ran-Ɛ-caprolactone) (mPEG-PLACL), is evaluated to overcome this problem. The results show that the hydrophilicity and degradation rate in artificial urine of mPEG-PLACL are both significantly increased. It is worth noting that the mPEG-PLACL shows a lower amount of encrustation after immersing the stents in the dynamic urinary extracorporeal circulation (DUEC) model for 7 days. In addition, 71% Ca and 92% Mg are inhibited in vivo by quantitative analysis. Pathological analysis exhibit that the mPEG-PLACL cause less diffuse mucosal hyperplasia after 7 weeks of implantation. All the results indicate that this new type of biodegradable material had an excellent potential for the ureteral stents in the future.

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

1982 ◽  
Vol 40 ◽  
pp. 210-211
Author(s):  
M.J. Murphy ◽  
R.R. Price ◽  
J.C. Sloman
Keyword(s):  
Cultured Cells ◽  
Human Tumor ◽  
Cell Type ◽  
Tumor Mass ◽  
Initial Cell ◽  
Cloning Assay ◽  
Human Tumor Cloning ◽  
The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

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