Degradation of Polyesters in Medical Applications

Rahman, Mashiur

doi:10.5772/47765

Cited by 11 publications

(10 citation statements)

References 48 publications

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“…Copolymers of poly(D,L-lactide-co-glycolide) are reported to degrade faster, depending on the composition ratio, within 5-6 months. Polyesters hydrolyze under acidic and basic conditions; 8 in contrast, some polyphosphoesters can be very stable under acidic conditions but degrade in the presence of a base. For polyphosphates, a typical water-soluble example is poly(methyl ethylene phosphate); while being stable at low pH, degradation of triester to diester bonds occurs under alkaline conditions within 5 h (at pH 12.3) to 21 months (pH 7.3).…”

Section: Introductionmentioning

confidence: 99%

Functional biodegradable polymers via ring-opening polymerization of monomers without protective groups

2018

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Biodegradable polymers are of current interest and chemical functionality in such materials is often demanded in advanced biomedical applications. Functional groups often are not tolerated in the polymerization process of ring-opening polymerization (ROP) and therefore protective groups need to be applied. Advantageously, several orthogonally reactive functions are available, which do not demand protection during ROP. We give an insight into available, orthogonally reactive cyclic monomers and the corresponding functional synthetic and biodegradable polymers, obtained from ROP. Functionalities in the monomer are reviewed, which are tolerated by ROP without further protection and allow further post-modification of the corresponding chemically functional polymers after polymerization. Synthetic concepts to these monomers are summarized in detail, preferably using precursor molecules. Post-modification strategies for the reported functionalities are presented and selected applications highlighted.

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Section: Introductionmentioning

confidence: 99%

Functional biodegradable polymers via ring-opening polymerization of monomers without protective groups

2018

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“…After purifications, the structures of the SB-based polyesters were confirmed by using 1 H and 13 The structures of the SB polyesters were further confirmed by 13 C NMR spectroscopy. After the polymerization, all the aromatic, −OCH 3 , and butylene bridge −CH 2 carbon peaks remained exactly the same as for the corresponding monomers, except that ethylene bridge −CH 2 (3 and 5) was shifted due to the electron-withdrawing nature of the ester groups.…”

Section: Synthesis Synthesis Of 4-(2-hydroxyethoxy)-2-methoxybenzalde...mentioning

confidence: 98%

“…1 H NMR (400.13 MHz, DMSO-d 6 ): δ H (ppm) 8.36 (s, imine −CH), 7.37 (s, Ar-CH), 7.24 (broad s, Ar-CH), 7.00 (s, Ar-CH), 4.71 (s, imine −NCH 2 ), 4.33 (br, Ar-OCH 2 ), 4.17 (br, Ar-OCH 2 CH 2 ), 3.74 (s, Ar-OCH 3 ), and 2.60 (s, aliphatic succinic-CH 2 ). 13 General Procedure for the Chemical Recyclability Studies. 1 g of each polymer (SBP3a−b, SBP4a−b, and SBP5a−b) was placed in a vial with 20 mL of 0.1 M HCl solution of methanol and deionized water (8:2 v/v) at room temperature for 24 h. After 24 h, the solution was poured into 200 mL of deionized water and stirred for 30 min.…”

Section: Synthesis Synthesis Of 4-(2-hydroxyethoxy)-2-methoxybenzalde...mentioning

confidence: 99%

“…Nuclear Magnetic Resonance Spectroscopy. 1 H and 13 C nuclear magnetic resonance spectroscopy (NMR) measurements were performed on an Avance 400 spectrometer at 298 K, and the chemical shifts were reported as δ values (ppm) of the residual DMSO-d 6 (2.50 and 39.52 ppm) taken as a reference. The proton frequency was 400.13 MHz, and the carbon frequency was 100.61 MHz.…”

Section: ■ Introductionmentioning

confidence: 99%

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Designed for Circularity: Chemically Recyclable and Enzymatically Degradable Biorenewable Schiff Base Polyester-Imines

Sathiyaraj

Najjarzadeh

Vanga

et al. 2023

ACS Sustainable Chem. Eng.

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Bio-based plastics potentially have several positive impacts on the environment; however, in order to make a real difference, they need to have managed and sustainable end of life. This means they should from the start be designed for chemical, mechanical, and/or organic (biological) recycling. Development of energy-efficient and selective chemical recycling processes is a necessary part in reaching truly circular plastic flows. Polyesters are generally well suited for chemical recycling due to the presence of reversible ester bonds. Utilization of dynamic covalent chemistry to include a second, even more easily reversed bond, such as Schiff base (SB, imine bond), could further facilitate chemical recycling, enabling depolymerization back to monomeric products under mild conditions. Here, we present the synthesis of three vanillin-derived SB monomers SBM1, SBM2, and SBM3 and the corresponding polymers SBP3a–b, SBP4a–b, and SBP5a–b. Three different diamines and two potentially bio-sourced diesters were utilized to yield altogether six different polyester-imines with different aliphatic/aromatic contents. All the obtained SB-based polyesters were thermally stable at ∼290–330 °C and had a high char yield during the pyrolysis, which may indicate inherent flame resistance. All the polyesters were amorphous with glass transition temperatures from 36 to 76 °C. The chemical recyclability and hydrolytic degradation of the synthesized polyesters was evaluated by using real-time 1H NMR spectroscopy. Finally, the susceptibility of the synthesized polyester-imines to enzymatic degradation by PETase was demonstrated. The experimental results were further supported by induced-fit docking experiments to theoretically evaluate the potential productive binding of the produced polyester-imines and intermediates thereof to the active site of PETase.

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“…Although exhibiting similar spectra, HCl-treated membranes did not demonstrate significant reduction in WCA, which correlated with a much lower detection intensity in the aforementioned peaks (Figure 8c). This may be because hydrolysis of esters catalysed by acid is much slower at any given temperature than alkali-catalysed hydrolysis (Mashiur 2012). It may be that the small alteration in surface chemistry that was detected by ATR-FTIR for HCl treated membranes was not significant enough to translate to a change in physical properties.…”

Section: Wettabilitymentioning

confidence: 99%

Development of Permanent Artificial Bowel Replacement Substrates

Koysombat

Haneef

2021

Preprint

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Short bowel syndrome (SDS) is a malabsorption disorder caused by loss of function of the small intestine, either by trauma or innately. Current treatment options include parenteral nutrition (PN) or allograft transplants. Long term PN dependence can lead to complications due to line infections and toxicity from the formula itself. A lack of healthy donors results in long waiting lists and high mortality rates. With allograft transplants, long-term graft and patient survival rates are poor (48% and 39% respectively at 5 years); graft loss occurs due to rejection (48%), thrombosis (28%), sepsis (12%); main causes of death are due to bacterial infection (94%) and rejection. Costs associated with PN annually per patient approximate to GBP40,000, whereas one allograft procedure costs approximately GBP80,000; not including intervention due to complications. Interest in developing an off-the-shelf bioengineered alternative have been expressed. Autologous transplants could be a more beneficial route to improving survival rates, enabling the transplant of patients healthy cells back to them. We describe here the development of a synthetic poly(ethylene terephthalate) scaffold using electrospinning, which showed excellent physical and chemical characteristics; high surface area:volume ratio, high mechanical strength, high porosity, and the ability to be chemically/physically functionalised without losing integrity in structure and physical properties. The cost of electrospinning is far lower in comparison to the current available treatment options, potentially providing a stable, off-the-shelf, ready-to-culture product as the need arises for applications in tissue engineered small intestine (TESI), or 3D models for small bowel research.

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Degradation of Polyesters in Medical Applications

Cited by 11 publications

References 48 publications

Functional biodegradable polymers via ring-opening polymerization of monomers without protective groups

Functional biodegradable polymers via ring-opening polymerization of monomers without protective groups

Designed for Circularity: Chemically Recyclable and Enzymatically Degradable Biorenewable Schiff Base Polyester-Imines

Development of Permanent Artificial Bowel Replacement Substrates

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