Characterization of load dependent creep behavior in medically relevant absorbable polymers

Dreher, Maureen L.; Nagaraja, Srinidhi; Bui, Hieu T.; Hong, Danny

doi:10.1016/j.jmbbm.2013.10.005

Cited by 15 publications

(9 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The higher solubility of longer chain glycolic oligomers as compared with lactic oligomers suggests glycolic units are more hydrophilic and, therefore, more soluble in water than lactic units. This observation is in good agreement with previous findings as discussed earlier . As the degradation proceeded, the amounts of oligomers in both L and G regions increased as indicated by expansion in the corresponding contour areas.…”

Section: Resultssupporting

confidence: 93%

Mapping intermediate degradation products of poly(lactic‐co‐glycolic acid) in vitro

Nemes

Guo

2017

J Biomed Mater Res

View full text Add to dashboard Cite

There is widespread interest in using absorbable polymers, such as poly(lactic-co-glycolic acid) (PLGA), as components in the design and manufacture of new-generation drug eluting stents (DES). PLGA undergoes hydrolysis to progressively degrade through intermediate chemical entities to simple organic acids that are ultimately absorbed by the human body. Understanding the composition and structure of these intermediate degradation products is critical not only to elucidate polymer degradation pathways accurately, but also to assess the safety and performance of absorbable cardiovascular implants. However, analytical approaches to determining the intermediate degradation products have yet to be established and evaluated in a standard or regulatory setting. Hence, we developed a methodology using electrospray ionization mass spectrometry to qualitatively and quantitatively describe intermediate degradation products generated in vitro from two PLGA formulations commonly used in DES. Furthermore, we assessed the temporal evolution of these degradation products using time-lapse experiments. Our data demonstrated that PLGA degradation products via heterogeneous cleavage of ester bonds are modulated by multiple intrinsic and environmental factors, including polymer chemical composition, degradants solubility in water, and polymer synthesis process. We anticipate the methodologies and outcomes presented in this work will elevate the mechanistic understanding of comprehensive degradation profiles of absorbable polymeric devices, and facilitate the design and regulation of cardiovascular implants by supporting the assessments of the associated biological response to degradation products. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1129-1137, 2018.

show abstract

Section: Resultssupporting

confidence: 93%

Mapping intermediate degradation products of poly(lactic‐co‐glycolic acid) in vitro

Nemes

Guo

2017

J Biomed Mater Res

View full text Add to dashboard Cite

show abstract

“…Due to the cost factors, current research is mainly focused on biomedical engineering 2,3 . However, devices based on biodegradable polymers are prone to viscoelastic plastic behavior, which may cause the device failure 4,5 . A typical case is the tissue engineering scaffold 6,7 .…”

Section: Introductionmentioning

confidence: 99%

“…2,3 However, devices based on biodegradable polymers are prone to viscoelastic plastic behavior, which may cause the device failure. 4,5 A typical case is the tissue engineering scaffold. 6,7 The scaffold provides structural support and promotes the proliferation and differentiation of daughter cells in vivo, and forms new tissues or organs compatible with the original function.…”

Section: Introductionmentioning

confidence: 99%

A modified creep model of polylactic acid (PLA‐max) materials with different printing angles processed by fused filament fabrication

Yao

Deng

et al. 2020

J of Applied Polymer Sci

View full text Add to dashboard Cite

The creep behavior caused by the viscous mechanical effect of biodegradable polylactic acid (PLA‐max) material is of great significance to its application. To better understand the creep properties of PLA‐max materials processed by fused filament fabrication, the effects of printing parameters including printing angle and layer thickness on them are studied theoretically and experimentally. The experimental results show that within the range of loading stress and loading time, the creep deformation of the PLA‐max material decreases with the increase of the printing angle or the decrease of the layer thickness. The experimental results are processed and analyzed, and a modified Burger model is proposed to quantitatively analyze the creep deformation of PLA‐max. In this modified Burger model, the four parameters are functions of printing angle and stress level. The modified model can accurately calculate the creep deformation of the specimen at other printing angles, which provides an important reference for the design of functional structures with specific mechanical properties.

show abstract

“…Prior to degradation studies, a subset of specimens were subjected to creep loading according to the methods described in Dreher et al, 26 over the course of 30 min to induce molecular alignment, macroscopic geometric changes, and elongation in the tensile bars. Creep was applied as a static 300N load to PLGA tensile bar specimens while immersed in a diH 2 O bath at 37…”

Section: Predegradation Creepmentioning

confidence: 99%

“…(1)] was measured by subtracting the area under the crystallization exotherm (H crystal ) from the area of the melt endotherm (H melt ) and dividing the difference by the energy required to melt 100% crystalline poly-L-lactide (i.e., 93.1 J/g 28 ). This value for the reference heat of fusion was applied to PLGA crystallinity calculations as done previously 18,26 due to the high degree of L-lactide in the polymer and a lack of data for the reference heat of fusion for all copolymer architectures.…”

Section: Crystallinity Measurementsmentioning

confidence: 99%

Creep loading during degradation attenuates mechanical property loss in PLGA

Dreher

Nagaraja

2014

J Biomed Mater Res

Self Cite

View full text Add to dashboard Cite

While absorbable materials and medical devices primarily degrade through hydrolysis, their degradation kinetics are sensitive to environmental conditions, including temperature, pH, and mechanical loading. While there is some consistent information in the literature suggesting that strain controlled loading accelerates strength loss, there is much more limited information on the interaction between degradation and mechanical load applied under force control. Force control conditions impose a different stress state on the material and therefore, may exhibit different effects on degradation. In this study, the interaction between loading and degradation rate for an exemplary absorbable polymer, poly(l‐lactide‐co‐glycolide), was investigated. The results indicated that load during degradation results in significant polymer creep, which is associated with increased force loss, but decreased strength loss (i.e., stress based parameters such as ultimate stress). This study further identified that changes to the degradation kinetics from exposure to loading were not associated with alterations to polymer crystallinity but were associated with delayed loss of molecular weight. Overall, these results demonstrate the importance of investigating the interaction between loading and degradation and that physical changes, such as those induced by creep, rather than chemical changes offer the strongest explanation for alteration of degradation kinetics. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 700–708, 2015.

show abstract

Characterization of load dependent creep behavior in medically relevant absorbable polymers

Cited by 15 publications

References 34 publications

Mapping intermediate degradation products of poly(lactic‐co‐glycolic acid) in vitro

Mapping intermediate degradation products of poly(lactic‐co‐glycolic acid) in vitro

A modified creep model of polylactic acid (PLA‐max) materials with different printing angles processed by fused filament fabrication

Creep loading during degradation attenuates mechanical property loss in PLGA

Contact Info

Product

Resources

About