scholarly journals Use of peak sharpening effects to improve the separation of chiral compounds with molecularly imprinted porous polymer layer open-tubular capillaries

2017 ◽  
Vol 38 (8) ◽  
pp. 1179-1187 ◽  
Author(s):  
Chadin Kulsing ◽  
Yuanzhong Yang ◽  
Jamil M. Chowdhury ◽  
Reinhard I. Boysen ◽  
Milton T. W. Hearn
Keyword(s):  
Porous Polymer ◽  
Polymer Layer ◽  
Molecularly Imprinted ◽  
Chiral Compounds

scholarly journals Robocasting of Single and Multi-Functional Calcium Phosphate Scaffolds and Its Hybridization with Conventional Techniques: Design, Fabrication and Characterization

2020 ◽  
Vol 10 (23) ◽  
pp. 8677
Author(s):  
Mehdi Mohammadi ◽  
Patricia Pascaud-Mathieu ◽  
Valeria Allizond ◽  
Jean-Marc Tulliani ◽  
Bartolomeo Coppola ◽  
...  
Keyword(s):  
Surrounding Medium ◽  
Silver Ions ◽  
Octacalcium Phosphate ◽  
Hybrid Structure ◽  
Functionally Graded ◽  
Porous Polymer ◽  
Polymer Layer ◽  
Polymer Scaffolds ◽  
Salt Leaching ◽  
Porous Part

In this work, dense, porous, and, for the first time, functionally-graded bi-layer scaffolds with a cylindrical geometry were produced from a commercially available hydroxyapatite powder using the robocasting technique. The bi-layer scaffolds were made of a dense core part attached to a surrounding porous part. Subsequently, these bi-layer robocast scaffolds were joined with an outer shell of an antibacterial porous polymer layer fabricated by solvent casting/salt leaching techniques, leading to hybrid ceramic-polymer scaffolds. The antibacterial functionality was achieved through the addition of silver ions to the polymer layer. All the robocast samples, including the bi-layer ones, were first characterized through scanning electron microscopy observations, mechanical characterization in compression and preliminary bioactivity tests. Then, the hybrid bi-layer ceramic-polymer scaffolds were characterized through antimicrobial tests. After sintering at 1300 °C for 3 h, the compressive strengths of the structures were found to be equal to 29 ± 4 MPa for dense samples and 7 ± 4 MPa for lattice structures with a porosity of 34.1%. Bioactivity tests performed at 37 °C for 4 weeks showed that the precipitated layer on the robocast samples contained octacalcium phosphate. Finally, it was evidenced that the hybrid structure was effective in releasing antibacterial Ag+ ions to the surrounding medium showing its potential efficiency in limiting Staphylococcus aureus proliferation during surgery.

scholarly journals Smart Microneedles with Porous Polymer Coatings for pH-Responsive Drug Delivery

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1834 ◽  
Author(s):  
Ullah ◽  
Khan ◽  
Choi ◽  
Kim
Keyword(s):  
Drug Delivery ◽  
Controlled Release ◽  
Drug Release ◽  
Sodium Bicarbonate ◽  
Porous Polymer ◽  
Polymer Layer ◽  
Ph Responsive ◽  
Acidic Microenvironment ◽  
Model Drug

: This work demonstrates a simple approach for coating a porous polymer layer on stainless-steel (SS) microneedles characterized by a pH-responsive formulation for self-regulated drug delivery. For many drug-delivery applications, the release of therapeutic agents in an acidic microenvironment is desirable. Acid-sensitive polymers and hydrogels were extensively explored, but easily prepared polymeric microcarriers that combine acid sensitivity and biodegradability are rare. Here, we describe a simple and robust method of coating a porous polymer layer on SS microneedles (MNs) that release a model drug (lidocaine) in a pH-responsive fashion. It was constructed by packing the model drug and a pH-sensitive component (sodium bicarbonate) into the pores of the polymer layer. When this acid-sensitive formulation was exposed to the acidic microenvironment, the consequent reaction of protons (H+) with sodium bicarbonate (NaHCO3) yielded CO2. This effect generated pressure inside the pores of the coating and ruptured the thin polymer membrane, thereby releasing the encapsulated drug. Scanning electron micrographs showed that the pH-sensitive porous polymer-coated MNs exposed to phosphate-buffered saline (PBS) at pH 7.4 were characterized by closed pores. However, MNs exposed to PBS at pH 5.5 consisted of open pores and the thin membrane burst. The in vitro studies demonstrated the pH sensitivity of the drug release from porous polymer-coated MNs. Negligible release was observed for MNs in receiving media at pH 7.4. In contrast, significant release occurred when the MNs were exposed to acidic conditions (pH 5.5). Additionally, comparable results were obtained for drug release in vitro in porcine skin and in PBS. This revealed that our developed pH-responsive porous polymer-coated MNs could potentially be used for the controlled release of drug formulations in an acidic environment. Moreover, the stimuli-responsive drug carriers will enable on-demand controlled release profiles that may enhance therapeutic effectiveness and reduce systemic toxicity.

The measurement of the shear modulus of a porous polymer layer with two microphones

2009 ◽  
Vol 28 (5) ◽  
pp. 508-510 ◽  
Author(s):  
Vincent Gareton ◽  
Denis Lafarge ◽  
Sohbi Sahraoui
Keyword(s):  
Shear Modulus ◽  
Porous Polymer ◽  
Polymer Layer

scholarly journals Porous polymer coatings on metal microneedles for enhanced drug delivery

2018 ◽  
Vol 5 (4) ◽  
pp. 171609 ◽  
Author(s):  
Asad Ullah ◽  
Chul Min Kim ◽  
Gyu Man Kim
Keyword(s):  
Drug Delivery ◽  
Rhodamine B ◽  
Skin Penetration ◽  
Dip Coating ◽  
Polymer Coatings ◽  
Porous Polymer ◽  
Polymer Layer ◽  
Simple Method ◽  
Modified Surface ◽  
Rhodamine B Dye

We present a simple method to coat microneedles (MNs) uniformly with a porous polymer (PLGA) that can deliver drugs at high rates. Stainless steel (SS) MNs of high mechanical strength were coated with a thin porous polymer layer to enhance their delivery rates. Additionally, to improve the interfacial adhesion between the polymer and MNs, the MN surface was modified by plasma treatment followed by dip coating with polyethyleneimine, a polymer with repeating amine units. The average failure load (the minimum force sufficient for detaching the polymer layer from the surface of SS) recorded for the modified surface coating was 25 N, whereas it was 2.2 N for the non-modified surface. Calcein dye was successfully delivered into porcine skin to a depth of 750 µm by the porous polymer-coated MNs, demonstrating that the developed MNs can pierce skin easily without deformation of MNs; additional skin penetration tests confirmed this finding. For visual comparison, rhodamine B dye was delivered using porous-coated and non-coated MNs in gelatin gel which showed that delivery with porous-coated MNs penetrate deeper when compared with non-coated MNs. Finally, lidocaine and rhodamine B dye were delivered in phosphate-buffered saline (PBS) medium by porous polymer-coated and non-coated MNs. For rhodamine B, drug delivery with the porous-coated MNs was five times higher than that with the non-coated MNs, whereas 25 times more lidocaine was delivered by the porous-coated MNs compared with the non-coated MNs.

scholarly journals Atrazine Sensing Chip Based on Molecularly Imprinted Polymer Layer

2008 ◽  
Vol 76 (8) ◽  
pp. 541-544 ◽  
Author(s):  
Izumi KUBO ◽  
Reo SHOJI ◽  
Yusuke FUCHIWAKI ◽  
Hiroaki SUZUKI
Keyword(s):  
Molecularly Imprinted Polymer ◽  
Polymer Layer ◽  
Imprinted Polymer ◽  
Molecularly Imprinted

scholarly journals Using Chiral Magnetic Surface Molecularly Imprinted Polymers for Chiral Separation of Ofloxacin

2020 ◽  
Author(s):  
ZHAO CHEN ◽  
Wenzong Lu ◽  
Mengxiang Yang
Keyword(s):  
Molecularly Imprinted Polymer ◽  
Optical Rotation ◽  
High Specificity ◽  
Cost Effective ◽  
Magnetic Surface ◽  
Imprinted Polymer ◽  
Molecularly Imprinted ◽  
Chiral Reagent ◽  
Chiral Compounds ◽  
Cost Effective Method

Abstract BackgroundOfloxacin is an important drug with anti-bacterial effects, and (–)-ofloxacin has been shown to have better anti-bacterial activity than racemic ofloxacin. But chiral resolution of compounds is a major challenge worldwide. Many methods do not show high specificity to target molecules, causing errors in the separation of these pharmaceutical molecules, thus affecting the purity of drugs.MethodThe paper mainly research on a method for quick resolution of ofloxacin using chiral magnetic surface molecular imprinting polymers (chiral MMIP). Fe3O4 magnetic nanoparticles coated with silica is acted as the substrate. Chiral reagent is N-octyl-D-glucosamine as monomer, with ofloxacin as the template molecules to prepare magnetic surface molecularly imprinted polymer. The chiral polymer can be combined with (+)-ofloxacin, eventually (-)-ofloxacin was isolated. ResultsFinally by using extermal magnetic field and transmission electron microscopy (TEM), the character of magnetic surface molecularly imprinted polymer is tested, and The product was tested by ultraviolet spectrum and optical rotation tests and was confirmed to be (-)-ofloxacin. ConclusionA simple, rapid, and cost-effective method for separating chiral compounds was established.

Controlled Grafting of S-Naproxen Imprinted Layer on PVDF Microporous Membrane by ATRP

2010 ◽  
Vol 148-149 ◽  
pp. 1026-1030 ◽  
Author(s):  
Nai Ci Bing ◽  
Zhen Tian ◽  
Lu Ping Zhu ◽  
Hai Ying Jin ◽  
Ling Ling Wang ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Membrane Surface ◽  
Polymer Layer ◽  
Polymerization Time ◽  
Imprinted Polymer ◽  
Uv Spectrum ◽  
Structural Morphology ◽  
Molecularly Imprinted ◽  
Poly Vinylidene Fluoride ◽  
Independent Variable

Controlled grafting of S-naproxen-imprinting polymer layer on the poly(vinylidene fluoride) (PVDF) microporous was carried out by the surface-initiated atom transfer radical polymerization (ATRP). Polymerization time was used as the independent variable to manipulate the amount of grafted imprinting polymer on the membrane surface. SEM, SPM and UV spectrum were used to study the structural morphology and selectivity of membranes and probe the incorporation of imprinted polymer layer on the surface of PVDF membranes . Results indicate that the integration of ATRP and molecularly imprinted polymeriaztion realize preparation of molecular selective membranes and it is possible to tune selectivity and morphology in rational way by changing polymerziton times.

Controllable Imprinted Polymer Layer Coated Silica-Gel for S-1-(1-Naphthyl) Ethylamine Recognition by ATRP

2012 ◽  
Vol 508 ◽  
pp. 237-240 ◽  
Author(s):  
Nai Ci Bing ◽  
Xiang Rong Zhu ◽  
Zhen Tian ◽  
Hong Yong Xie ◽  
Li Jun Wang
Keyword(s):  
Silica Gel ◽  
Stationary Phases ◽  
Chiral Separations ◽  
Polymer Layer ◽  
Imprinted Polymer ◽  
Uv Spectrum ◽  
Structural Morphology ◽  
Molecularly Imprinted ◽  
Molecularly Imprinting Polymer ◽  
Ft Ir

Controlled grafting ofS-1-(1-naphthyl) Ethylamine-imprinting polymer layer on the silica-gel was carried out by the surface-initiated atom transfer radical polymerization (ATRP). Polymerization time was used as the independent variable to manipulate the amount of grafted imprinting polymer on the silica-gel. For comparison, molecularly imprinted polymers (MIPs) without silica-gel also prepared at the same condition. SEM, FT-IR and UV spectrum were used to study the structural morphology and selectivity of polymers and probe the incorporation of imprinted polymer layer on the surface of substrates. Results indicate that the integration of ATRP and molecularly imprinted polymerization realize preparation of molecular selective polymers and it is possible to tune selectivity and morphology in rational way by changing polymerization times. Meanwhile, we achieve a reference strategy for the development of molecularly imprinting polymer for drugs and to handle forms in certain applications such as chromatographic stationary phases for chiral separations.

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