scholarly journals Studies Based on Preparation, Physical Characteristics, and Cellular Pharmacological Activities of Thin PLGA Film Loaded with Geniposide

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Haiyan Zhang ◽  
Hao Liu ◽  
Nan Huang ◽  
Ya He ◽  
Tingting Lei ◽  
...  
Keyword(s):  
Single Molecule ◽  
Early Stage ◽  
Spectral Characteristics ◽  
Primary Study ◽  
Physical Parameters ◽  
Release Behavior ◽  
Vascular Stents ◽  
Whole Process ◽  
Drug Eluting ◽  
Plga Film

In this primary study, thin polylactic-co-glycolic acid (PLGA) film loaded with geniposide was first prepared and demonstrated on both physical and pharmacological aspects for its potential application on drug-eluting vascular stents. Physical parameters of geniposide-loaded thin film, such as crystal structure, molecular spectral characteristics, and release behavior in the whole process were detected. From X-Ray diffraction, the characteristic peak of crystal geniposide disappeared on geniposide-loaded PLGA film (GLPF) after it formed, which meant there was no agglomeration phenomenon, as geniposide was distributed in the form of single molecule. According to scanning electron microscopy (SEM) figure, the GLPF was more flat and uniform with better compactness. It inferred that release behavior of geniposide at the early stage (0~15 d) was in the form of free diffusion. Carrier PLGA began to degrade 15 days later, so the residual geniposide was also dissolved. Cellular pharmacological effects of geniposide on endothelial cells (ECs) and smooth muscle cells (SMCs) were also demonstrated on GLPF. 5% and 10% (w/w) geniposide-loaded PLGA (60 : 40) membrane indicated its significant effect on ECs promotion and SMCs inhibition. All provided feasible evidences for the development of new geniposide-coating vascular stent using PLGA as carrier.

scholarly journals Influence of Elongation of Paclitaxel-Eluting Electrospun-Produced Stent Coating on Paclitaxel Release and Transport Through the Arterial Wall after Stenting

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1165
Author(s):  
Zhanna K. Nazarkina ◽  
Boris P. Chelobanov ◽  
Konstantin A. Kuznetsov ◽  
Alexey V. Shutov ◽  
Irina V. Romanova ◽  
...  
Keyword(s):  
Drug Release ◽  
Arterial Wall ◽  
Release Kinetics ◽  
Artery Wall ◽  
Vascular Stents ◽  
Drug Eluting ◽  
Fiber Breaks ◽  
Stent Diameter ◽  
Stent Coating

It was previously shown that polycaprolactone (PCL)-based electrospun-produced paclitaxel (PTX)-enriched matrices exhibit long-term drug release kinetics and can be used as coatings for drug-eluting stents (DES). The installation of vascular stents involves a twofold increase in stent diameter and, therefore, an elongation of the matrices covering the stents, as well as the arterial wall in a stented area. We studied the influence of matrix elongation on its structure and PTX release using three different electrospun-produced matrices. The data obtained demonstrate that matrix elongation during stent installation does not lead to fiber breaks and does not interfere with the kinetics of PTX release. To study PTX diffusion through the expanded artery wall, stents coated with 5%PCL/10%HSA/3%DMSO/PTX and containing tritium-labeled PTX were installed into the freshly obtained iliac artery of a rabbit. The PTX passing through the artery wall was quantified using a scintillator β-counter. The artery retained the PTX and decreased its release from the coating. The retention of PTX by the arterial wall was more efficient when incubated in blood plasma in comparison with PBS. The retention/accumulation of PTX by the arterial wall provides a prolonged drug release and allows for the reduction in the dose of the drugs in electrospun-produced stent coatings.

Progress on precise regulation of vascular intimal repair by surface coating of vascular stent

2021 ◽  
Vol 18 ◽  
Author(s):  
Shihui Liu ◽  
Junchao Zhi ◽  
Shijie Li ◽  
Zhuoyue Song ◽  
Tao Gong ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Biological Response ◽  
Research Direction ◽  
Vascular Stent ◽  
Functional Layer ◽  
Vascular Stents ◽  
Drug Eluting ◽  
Genetic Level ◽  
Disease Related Gene

: In the past few decades, drug-eluting stents have made significant contributions to the treatment of coronary heart disease. However, due to the delayed healing of endothelial injuries caused by antiproliferative drugs and insufficient biocompatibility of vascular stent materials, late in-stent thrombosis and restenosis remain major challenges. Surface modification of cardiovascular materials to construct biological functional layer that can regulate the behavior of blood and vascular cells is an effective way to improve the clinical performance of vascular stents. This paper reviewed the common methods of surface bio-functional modification of cardiovascular materials, and especially proposed that take the advantage of the new concept of precision medicine, as well as the precise and orderly regulation properties of cardiovascular disease-related gene fragments on vascular biological response behavior, the construction of gene-eluting stents which can in-situ regulate vascular intimal repair at the molecular and genetic level will become an important research direction in the future.

Nanotechnology Applications in Biomedical Engineering

2015 ◽  
pp. 50-63
Author(s):  
Cajetan M. Akujuobi
Keyword(s):  
Dental Implants ◽  
21St Century ◽  
Biomedical Engineering ◽  
Well Being ◽  
Orthopedic Implants ◽  
Vascular Stents ◽  
Safety Aspects ◽  
Drug Eluting ◽  
And Mathematics ◽  
The Impact

The 21st century has seen a massive explosion in the applications of nanotechnology. These applications cover all areas of Science, Technology, Engineering, and Mathematics (STEM). The advantage of nanotechnology comes from the fact that it has revolutionized the miniaturizations of many products that are useful to the well-being of society. A typical nanotechnology application example in biomedical engineering is its usage as drug eluting interfaces for implantable devices, such as vascular stents, orthopedic implants, and dental implants. The purpose of this chapter is to discuss the various applications of nanotechnology to biomedical engineering. Some of the future nanotechnology applications in biomedical engineering include healthcare/medical, consumer medical goods, environmental, and electronics. The impact of nanotechnology applications to biomedical engineering is in many ways enabling humans to survive different ailments that otherwise could have been very difficult to manage. The safety aspects in the applications of nanotechnology to biomedical engineering are also examined.

Nanotechnology Applications in Biomedical Engineering

Oncology ◽  
2017 ◽  
pp. 352-365 ◽  
Author(s):  
Cajetan M. Akujuobi
Keyword(s):  
Dental Implants ◽  
21St Century ◽  
Biomedical Engineering ◽  
Well Being ◽  
Orthopedic Implants ◽  
Vascular Stents ◽  
Safety Aspects ◽  
Drug Eluting ◽  
And Mathematics ◽  
The Impact

The 21st century has seen a massive explosion in the applications of nanotechnology. These applications cover all areas of Science, Technology, Engineering, and Mathematics (STEM). The advantage of nanotechnology comes from the fact that it has revolutionized the miniaturizations of many products that are useful to the well-being of society. A typical nanotechnology application example in biomedical engineering is its usage as drug eluting interfaces for implantable devices, such as vascular stents, orthopedic implants, and dental implants. The purpose of this chapter is to discuss the various applications of nanotechnology to biomedical engineering. Some of the future nanotechnology applications in biomedical engineering include healthcare/medical, consumer medical goods, environmental, and electronics. The impact of nanotechnology applications to biomedical engineering is in many ways enabling humans to survive different ailments that otherwise could have been very difficult to manage. The safety aspects in the applications of nanotechnology to biomedical engineering are also examined.

scholarly journals The local Universe in the era of large surveys – I. Spectral classification of S0 galaxies

2020 ◽  
Vol 495 (4) ◽  
pp. 4135-4157 ◽  
Author(s):  
J L Tous ◽  
J M Solanes ◽  
J D Perea
Keyword(s):  
Dimensional Space ◽  
Spectral Characteristics ◽  
Principal Component ◽  
Morphological Type ◽  
Physical Parameters ◽  
Star Forming ◽  
Interesting Possibility ◽  
Low Dimensional ◽  
Free Machine

ABSTRACT This is the first paper in a series devoted to review the main properties of galaxies designated S0 in the Hubble classification system. Our aim is to gather abundant and, above all, robust information on the most relevant physical parameters of this poorly understood morphological type and their possible dependence on the environment, which could later be used to assess their possible formation channel(s). The adopted approach combines the characterization of the fundamental features of the optical spectra of $68\, 043$ S0 with heliocentric z ≲ 0.1 with the exploration of a comprehensive set of their global attributes. A principal component analysis is used to reduce the huge number of dimensions of the spectral data to a low-dimensional space facilitating a bias-free machine-learning-based classification of the galaxies. This procedure has revealed that objects bearing the S0 designation consist, despite their similar morphology, of two separate subpopulations with statistically inconsistent physical properties. Compared to the absorption-dominated S0, those with significant nebular emission are, on average, somewhat less massive, more luminous with less concentrated light profiles, have a younger, bluer, and metal-poorer stellar component, and avoid high-galaxy-density regions. Noteworthy is the fact that the majority of members of this latter class, which accounts for at least a quarter of the local S0 population, show star formation rates and spectral characteristics entirely similar to those seen in late spirals. Our findings suggest that star-forming S0 might be less rare than hitherto believed and raise the interesting possibility of identifying them with plausible progenitors of their quiescent counterparts.

scholarly journals Fluorescence-Labeled Amyloid Beta Monomer: A Molecular Dynamical Study

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3524
Author(s):  
János Gera ◽  
Gábor Paragi
Keyword(s):  
Single Molecule ◽  
Early Stage ◽  
Conformational Space ◽  
Dynamic Simulations ◽  
Dynamical Study ◽  
Fluorescence Dye ◽  
Aβ Aggregation ◽  
The Difference ◽  
Open Question ◽  
The Impact

The aggregation process of the Amyloidβ (Aβ) peptide is one of the central questions in Alzheimers’s research. Fluorescence-labeled single-molecule detection is a novel technique concerning the early stage investigation of Aβ aggregation, where the labeling dyes are covalently bound to the Aβ monomer. As the influence of the dye on the conformational space of the Aβ monomer can be significant, its effect on the seeding process is an open question. The applied fluorescent molecule continuously switches between an active (ON) and an inactive (OFF) state, where the latter supports an extra rotational restriction at many commercially available dyes. However, only a few theoretical studies simulated the Aβ monomer in the presence of a dye and none of them considered the difference between the ON and the OFF states. Therefore, we examined the impact of a selected fluorescence dye (Alexa 568) on the conformational space of the monomeric Aβ(1–42) peptide in its ON and OFF state by replica exchange molecular dynamic simulations. Investigations on secondary structure elements as well as dye-peptide contact analysis for the monomers are presented. Experimental and theoretical NMR shifts were contrasted to qualify the calculation protocol and theoretical values of the labeled and the non-labeled peptide were also compared. We found that the first five residues have higher helical propensity in the presence of the dye, and electrostatic properties could strongly affect the connection between the dye and the peptide parts.

Sustained drug release using cobalt oxide nanowires for the preparation of polymer-free drug-eluting stents

2018 ◽  
Vol 33 (3) ◽  
pp. 352-362 ◽  
Author(s):  
Tarek M Bedair ◽  
Il Jae Min ◽  
Wooram Park ◽  
Yoon Ki Joung ◽  
Dong Keun Han
Keyword(s):  
Drug Release ◽  
Cobalt Oxide ◽  
Drug Eluting Stents ◽  
Therapeutic Drug ◽  
Burst Release ◽  
Release Behavior ◽  
Cobalt Chromium ◽  
Oxide Nanowires ◽  
Drug Eluting

Polymer-based drug-eluting stents (DESs) represented attractive application for the treatment of cardiovascular diseases; however, polymer coating has caused serious adverse responses to tissues such as chronic inflammation due to acidic by-products. Therefore, polymer-free DESs have recently emerged as promising candidates for the treatment; however, burst release of drug(s) from the surface limited its applications. In this study, we focused on delivery of therapeutic drug from polymer-free (or -less) DESs through surface modification using cobalt oxide nanowires (Co3O4 NWs) to improve and control the drug release. The results demonstrated that Co3O4 NWs could be simply fabricated on cobalt–chromium substrate by ammonia-evaporation-induced method. The Co3O4 NWs were uniformly arrayed with diameters of 50–100 nm and lengths of 10 µm. It was found that Co3O4 NWs were comparatively stable without any delamination or change of the morphology under in vitro long-term stability using circulating system. Sirolimus was used as a model drug for studying in vitro release behavior under physiological conditions. The sirolimus release behavior from flat cobalt–chromium showed an initial burst (over 90%) after one day. On the other hand, Co3O4 NWs presented a sustained sirolimus release rate for up to seven days. Similarly, the polymer-less specimens on Co3O4 NWs substrates sustained sirolimus release for a longer-period of time when compared to flat Co–Cr substrates. In summary, the current approach of using Co3O4 NWs-based substrates might have a great potential to sustain drug release for drug-eluting implants and medical devices including stents.

scholarly journals Vascular Stents Coated with Electrospun Drug-Eluting Material: Functioning in Rabbit Iliac Artery

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1741
Author(s):  
Konstantin A. Kuznetsov ◽  
Ivan S. Murashov ◽  
Vera S. Chernonosova ◽  
Boris P. Chelobanov ◽  
Alena O. Stepanova ◽  
...  
Keyword(s):  
Blood Flow ◽  
Iliac Artery ◽  
Balloon Catheter ◽  
Bare Metal Stents ◽  
Blood Flow Rate ◽  
Metal Stents ◽  
Bare Metal ◽  
Vascular Stents ◽  
Drug Eluting

A stenting procedure aimed at blood flow restoration in stenosed arteries significantly improves the efficiency of vascular surgery. However, the current challenge is to prevent neointimal growth, which reduces the vessel lumen, in the stented segments in the long run. We tested in vivo drug-eluting coating applied by electrospinning to metal vascular stents to inhibit the overgrowth of neointimal cells via both the drug release and mechanical support of the vascular wall. The blend of polycaprolactone with human serum albumin and paclitaxel was used for stent coating by electrospinning. The drug-eluting stents (DESs) were placed using a balloon catheter to the rabbit common iliac artery for 1, 3, and 6 months. The blood flow rate was ultrasonically determined in vivo. After explantation, the stented arterial segment was visually and histologically examined. Any undesirable biological responses (rejection or hemodynamically significant stenosis) were unobservable in the experimental groups. DESs were less traumatic and induced weaker neointimal growth; over six months, the blood flow increased by 37% versus bare-metal stents, where it increased by at least double the rate. Thus, electrospun-coated DESs demonstrate considerable advantages over the bare-metal variants.

A STOCHASTIC CAGE MODEL FOR THE ORIENTATIONAL DYNAMICS OF SINGLE MOLECULES IN NEMATIC PHASES

1999 ◽  
Vol 10 (02n03) ◽  
pp. 375-389 ◽  
Author(s):  
DIEGO FREZZATO ◽  
GIACOMO SAIELLI ◽  
ANTONINO POLIMENO ◽  
PIER LUIGI NORDIO
Keyword(s):  
Single Molecule ◽  
Statistical Data ◽  
Md Simulations ◽  
Time Correlation ◽  
General Assumption ◽  
Physical Parameters ◽  
Librational Motion ◽  
Orientational Dynamics ◽  
Nematic Phases ◽  
Single Set

A stochastic cage model for the orientational dynamics of a molecule in isotropic and nematic phases of a liquid crystal has been developed, following the methodology introduced in Refs. 1, 2. The model has been parameterized on the basis of statistical data obtained from the analysis of Molecular Dynamics (MD) simulations of a Gay–Berne mesogen and is based on the general assumption of a timescale separation between the fast inertial librational motion inside the instantaneous cage potential and the slow diffusive motion of the cage itself. The model is able to reproduce single molecule time correlation functions both for the angular momentum and the reorientation of the long molecular axis of the molecule. A complete description of the dynamics of a Gay–Berne particle is given with a single set of physical parameters, from a very fast (hundreds of femtoseconds) timescale up to a timescale of nanoseconds.

scholarly journals Impact of stent edge dissection detected by optical coherence tomography after current-generation drug-eluting stent implantation

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259693
Author(s):  
Hiroyuki Jinnouchi ◽  
Kenichi Sakakura ◽  
Tomonobu Yanase ◽  
Yusuke Ugata ◽  
Takunori Tsukui ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Clinical Outcomes ◽  
Cardiac Death ◽  
Target Lesion ◽  
Drug Eluting Stent ◽  
Primary Study ◽  
Optical Coherence ◽  
Current Generation ◽  
Drug Eluting ◽  
Inverse Probability Weighted

Background Stent edge dissection (SED) is a well-known predictor of worse clinical outcomes. However, impact of SED after current-generation drug-eluting stent (DES) implantation remains unknown since there was no study using only current-generation DES to assess impact of SED. This study aimed to investigate a relationship between SED detected by optical coherence tomography (OCT) and clinical outcomes after current-generation DES implantation. Methods This study enrolled 175 patients receiving OCT after current-generation DES implantation. The SED group was compared with the non-SED group in terms of the primary study endpoints which was the cumulative incidence of major adverse cardiac event (MACE) composed of cardiac death, target vessel myocardial infarction (TV-MI), and clinically-driven target lesion revascularization (CD-TLR). Results Of 175 patients, SED detected by OCT was observed in 32 patients, while 143 patients did not show SED. In the crude population, the SED group showed a significantly higher incidence of CD-TLR, definite stent thrombosis, TV-MI and cardiac death relative to the non-SED group. After adjustment by an inverse probability weighted methods, the SED group showed a significantly higher incidence of MACE compared with the non-SED group (hazard ratio 3.43, 95% confidence interval 1.09–10.81, p = 0.035). Fibrocalcific or lipidic plaques, greater lumen eccentricity, and stent-oversizing were the predictors of SED. Conclusions SED detected by OCT after the current-generation DES implantation led to unfavorable outcomes. Aggressive post-dilatation around the stent edge might worse clinical outcomes due to SED, although achievement of optimal stent expansion is strongly encouraged to improve clinical outcomes.

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