<i>In Vitro</i>Degradation Effects on Strength, Stiffness, and Creep of PLLA/PBS: A Potential Stent Material

Kimble, L. D.; Bhattacharyya, Debes

doi:10.1080/00914037.2014.945203

Cited by 28 publications

(11 citation statements)

References 26 publications

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“…Taking all these considerations into account, quantification of degradation effects on stent mechanical properties cannot be made solely with pyramidal nanoindentation. So, effects of material degradation, non-uniformity of the polymer chain alignment and testing methodology (i.e., ISE) cannot be separated in this case, and consequently, additional techniques such as spherical nanoindentation and/or structural testing [27] need to be sought in order to deliver more consistent measurements of the material properties over degradation.…”

Section: Discussionmentioning

confidence: 99%

Mechanical and chemical characterisation of bioresorbable polymeric stent over two-year in vitro degradation

et al. 2019

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Polymeric stent is a temporary cardiovascular scaffold, made of biodegradable poly (l-lactic) acid, to treat coronary artery stenosis, with expected resorption by the human body over two to three years. In this paper, the mechanical properties of a polymeric stent over two-year in vitro degradation were studied and characterised using atomic force microscopy and nanoindentation techniques, complemented with analyses of weight loss, gel permeation chromatography and differential scanning calorimetry. Atomic force microscopy assessed stent degradation at the surface, whilst nanoindentation was able to investigate the property at a greater depth into the material. No significant changes to the Young's modulus were observed with the atomic force microscopy due to bulk degradation nature of the polymer. Chemical analyses demonstrated a reduction of molecular weight and an increase of crystallinity, indicating degradation of the stents.Berkovich nanoindentation showed a trend of reduction in modulus over in vitro degradation, which was, however, not continuous due to the variations of measurements associated with the pyramidal indenter tip and the semi-crystalline structure of the polymer.

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Section: Discussionmentioning

confidence: 99%

Mechanical and chemical characterisation of bioresorbable polymeric stent over two-year in vitro degradation

et al. 2019

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“…Therefore, each polymer was investigated for its own characteristics. Recently, it was reported by Kimble et al (2014) that after a 24-week degradation study, the molecular weight of 75:25 wt.% PLLA/PBS decreased to 2.8 × 10 3 g/mol from an initial molecular weight of 49 × 10 3 g/mol. Zhang et al blended PLLA with PBS in a melt state and carried out a biodegradation study for 60 days by burying the samples in soil .…”

Section: Discussionmentioning

confidence: 99%

In vitro evaluation of PLLA/PBS sponges as a promisingbiodegradable scaffold for neural tissue engineering

Altinişik¹,

Kök²,

Yücel³

et al. 2017

Turk J Biol

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In tissue engineering, the use of poly-L-lactic acid (PLLA)/polybutylene succinate (PBS) blend for the construction of scaffold is very limited. Moreover, polymeric sponges fabricated from PLLA/PBS have not been studied for neural tissue engineering. In the present study, the potential of the utility of PLLA/PBS polymeric sponges seeded with Schwann cells was investigated. PLLA and PBS were blended in order to increase the processability and tune the crystallinity, porosity, and degradation rate of the resulted polymeric sponges. These sponges were then seeded with Schwann cells. Porosity analysis showed that there were no significant differences between different compositions of PLLA/PBS blends; however, the porosity was slightly higher in PLLA/PBS (3%, w/v, 2:1) scaffold. Degradation profiles were also investigated for 120 days and almost 25% weight of PLLA/PBS (6%, 4%, 2%, w/v, 1:1) scaffolds and 18% weight of PLLA/PBS (3%, w/v, 2:1) scaffolds were lost at the end of 120 days. In vitro cell culture studies were also performed and the results proved that all PLLA/PBS blended scaffolds were biocompatible. The highest cell proliferation was observed for PLLA/PBS (3%, w/v, 2:1) scaffolds and this construct can be considered a promising biodegradable scaffold for neural tissue engineering.

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“…All materials tested had glass-transition temperatures in the range of 56.1-68 C providing structural stability in the temperature range of biomedical applications. Kimble and Bhattacharyya (2015) assessed mechanical properties of PLLA during in vitro degradation in comparison to a co-polymer material (PLLA/PBS) by incubating dogbone specimens for 24 weeks in PBS at 37°C. In comparison to the co-polymer tested, neat PLLA maintained integrity throughout 24 weeks, showing increasing creep resistance in the initial 8-week degradation period.…”

Section: Mechanical Performance Of Scaffolds With Degradationmentioning

confidence: 99%

Experimental and computational studies of poly-L-lactic acid for cardiovascular applications: recent progress

Naseem

Zhao

Liu

et al. 2017

Mech Adv Mater Mod Process

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Stents are commonly used in medical procedures to alleviate the symptoms of coronary heart disease, a prevalent modern society disease. These structures are employed to maintain vessel patency and restore blood flow. Traditionally stents are made of metals such as stainless steel or cobalt chromium; however, these scaffolds have known disadvantages. An emergence of transient scaffolds is gaining popularity, with the structure engaged for a required period whilst healing of the diseased arterial wall occurs. Polymers dominate a medical device sector, with incorporation in sutures, scaffolds and screws. Thanks to their good mechanical and biological properties and their ability to degrade naturally. Polylactic acid is an extremely versatile polymer, with its properties easily tailored to applications. Its dominance in the stenting field increases continually, with the first polymer scaffold gaining FDA approval in 2016. Still some challenges with PLLA bioresorbable materials remain, especially with regard to understanding their mechanical response, assessment of its changes with degradation and comparison of their performance with that of metallic drug-eluting stent. Currently, there is still a lack of works on evaluating both the pre-degradation properties and degradation performance of these scaffolds. Additionally, there are no established material models incorporating non-linear viscoelastic behaviour of PLLA and its evolution with in-service degradation. Assessing these features through experimental analysis accompanied by analytical and numerical studies will provide powerful tools for design and optimisation of these structures endorsing their broader use in stenting. This overview assesses the recent studies investigating mechanical and computational performance of poly(l-lactic) acid and its use in stenting applications.

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In VitroDegradation Effects on Strength, Stiffness, and Creep of PLLA/PBS: A Potential Stent Material

Cited by 28 publications

References 26 publications

Mechanical and chemical characterisation of bioresorbable polymeric stent over two-year in vitro degradation

Mechanical and chemical characterisation of bioresorbable polymeric stent over two-year in vitro degradation

In vitro evaluation of PLLA/PBS sponges as a promisingbiodegradable scaffold for neural tissue engineering

Experimental and computational studies of poly-L-lactic acid for cardiovascular applications: recent progress

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