Molecular design and evaluation of biodegradable polymers using a statistical approach

Lewitus, Dan Y.; Rios, Fabian; Rojas, Ramiro; Kohn, Joachim

doi:10.1007/s10856-013-5008-0

Cited by 9 publications

(7 citation statements)

References 32 publications

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“…Unique relations between Mn and both the modulus and and strain retention were also observed. By contrast, Weir et al [164,167] found that there was a linear relationship, while Farrar and Gillson [18] and Tsuji [166] used empirical curve fitting to characterise the relationship, as did Lewitus et al [168] for the degradation of tyrosinederived terpolymers.…”

Section: Modelling the Effect Of Hydrolytic Degradation On Mechanical Propertiesmentioning

confidence: 99%

Lifetime prediction of biodegradable polymers

Laycock

Nikolić

Colwell

et al. 2017

Progress in Polymer Science

472

364

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The determination of the safe working life of polymer materials is important for their successful use in engineering, medicine and consumer-goods applications. An understanding of the physical and chemical changes to the structure of widely-used polymers such as the polyolefins, when exposed to aggressive environments, has provided a framework for controlling their ultimate service lifetime by either stabilizing the polymer or chemically accelerating the degradation reactions. The recent focus on biodegradable polymers as replacements for more bio-inert materials such as the polyolefins in areas as diverse as packaging and as scaffolds for tissue engineering has highlighted the need for a review of the approaches to being able to predict the lifetime of these materials. In many studies the focus has not been on the embrittlement and fracture of the material (as it would be for a polyolefin) but rather the products of degradation, their toxicity and ultimate fate when in the environment, which may be the human body. These differences are primarily due to time-scale. Different approaches to the problem have arisen in biomedicine, such as the kinetic control of drug delivery by the bio-erosion of polymers, but the similarities in mechanism provide real prospects for the prediction of the safe service lifetime of a biodegradable polymer as a structural material. Common mechanistic themes that emerge include the diffusion-controlled process of water sorption and conditions for surface versus bulk degradation, the role of hydrolysis versus oxidative degradation in controlling the rate of polymer chain scission and strength loss and the specificity of enzyme-mediated reactions.

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Section: Modelling the Effect Of Hydrolytic Degradation On Mechanical Propertiesmentioning

confidence: 99%

Lifetime prediction of biodegradable polymers

Laycock

Nikolić

Colwell

et al. 2017

Progress in Polymer Science

472

364

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“…For polycarbonates, we used a random block copolymer composed of DTE, DT, and different amounts of PEG (poly(DTE‐ co ‐xx% DT‐ co ‐yy% PEG carbonate) (referred to as Exxyy[ n k]), where xx and yy are percentage mole fractions of DT and PEG respectively, and n is the molecular weight of PEG in kDa (Figure 1). [ 11,12 ] E1001(1k) used here is a terpolymer comprised of 89% DTE, 10% DT free acid, and 1% low molecular weight PEG (1 kDa). E1001(1k) is a degradable polycarbonate that has successfully been heat extruded into rods for orthopedic applications, and drawn into fibers for nerve guidance conduit fabrication.…”

Section: Methodsmentioning

confidence: 99%

Thermal processing of a degradable carboxylic acid‐functionalized polycarbonate into scaffolds for tissue engineering

Murthy

Shultz

Iovine

et al. 2021

Polymer Engineering & Sci

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Degradable polymers are often desirable for the fabrication of medical implants, but thermal processing of these polymers is a challenge. We describe here how these problems can be addressed by discussing the extrusion of fibers and injection molding of bone pins from a hydrolytically degradable tyrosine‐derived polycarbonate. Our initial attempts produced fibers and pins with bubbles, voids, and discoloration and resulted in the formation of large polymer plugs that seized screws and blocked extruder dies. The material and process parameters that contribute to these issues were investigated by studying the physical and chemical changes that occur during processing. Differential scanning calorimetry and thermogravimetric analysis combined with IR analysis showed that residual moisture and solvents in conjunction with heat cause degradation and crosslinking as indicated by gel permeation chromatography. Rheology and melt flow index measurements were useful in characterizing the extent of dependence of polymer viscosity on temperature and molecular weight. With these insights, we could process our polymer into fibers and rods by controlling residual moisture, time, and temperature and by adjusting processing parameters in real time. The systematic approach described here is applicable to other degradable polymers that are difficult to process.

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“…Each material is characterized by unique properties. Indeed, the molecular structure, the polymerization transition temperature, and biomechanical behavior are some of the different properties that may exist among the materials [ 73 ]. For instance, PGA is characterized by rapid degradation time, which affects its biomechanical properties [ 47 , 48 ].…”

Section: Tevgs Derived From Synthetic Polymersmentioning

confidence: 99%

Future Perspectives in Small-Diameter Vascular Graft Engineering

et al. 2020

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The increased demands of small-diameter vascular grafts (SDVGs) globally has forced the scientific society to explore alternative strategies utilizing the tissue engineering approaches. Cardiovascular disease (CVD) comprises one of the most lethal groups of non-communicable disorders worldwide. It has been estimated that in Europe, the healthcare cost for the administration of CVD is more than 169 billion €. Common manifestations involve the narrowing or occlusion of blood vessels. The replacement of damaged vessels with autologous grafts represents one of the applied therapeutic approaches in CVD. However, significant drawbacks are accompanying the above procedure; therefore, the exploration of alternative vessel sources must be performed. Engineered SDVGs can be produced through the utilization of non-degradable/degradable and naturally derived materials. Decellularized vessels represent also an alternative valuable source for the development of SDVGs. In this review, a great number of SDVG engineering approaches will be highlighted. Importantly, the state-of-the-art methodologies, which are currently employed, will be comprehensively presented. A discussion summarizing the key marks and the future perspectives of SDVG engineering will be included in this review. Taking into consideration the increased number of patients with CVD, SDVG engineering may assist significantly in cardiovascular reconstructive surgery and, therefore, the overall improvement of patients’ life.

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Molecular design and evaluation of biodegradable polymers using a statistical approach

Cited by 9 publications

References 32 publications

Lifetime prediction of biodegradable polymers

Lifetime prediction of biodegradable polymers

Thermal processing of a degradable carboxylic acid‐functionalized polycarbonate into scaffolds for tissue engineering

Future Perspectives in Small-Diameter Vascular Graft Engineering

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