Recent Advances in Polyesters for Biomedical Imaging

Attia, Mohamed F.; Brummel, Beau R.; Lex, Timothy R.; Horn, Brooke A. Van; Whitehead, Daniel C.; Alexis, Frank

doi:10.1002/adhm.201800798

Cited by 27 publications

(31 citation statements)

References 84 publications

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“…Unlike commonly used PLA/PLG polymers, PCL polymers slowly degrade into less acidic, low molecular weight by-products, preventing the generation of a toxic environment 27 . Although the relative X-ray intensity of iPCL was lower than the iPLA and iPMMD materials, the access to a class of bioresorbable X-ray enhancing polycaprolactones may be useful for some medical applications 4 . We selected the iPLA material for further studies based on its strong X-ray contrasting properties coupled with its relative ease of synthesis from economical, readily available starting materials.…”

Section: Resultsmentioning

confidence: 99%

“…3). To target a predictable ratio of copolymers, a conventional thermal ring-opening polymerization with tin (II) 2-ethylhexanoate was exploited 4,26 . Isolation of the final products was carried out by means of precipitation in cold methanol followed by centrifugation at -9 °C for 5 min followed by freeze-drying for 3 days.…”

Section: Resultsmentioning

confidence: 99%

“…121-122 °C, 58%, 1.03 g). Rf = 0.26 (70:30 hexanes:EtOAc) 1 (4); Typical Procedure. To a flame dried round bottom flask equipped with a stir bar was added 4-iodo-L-phenylalanine (6.9 mmol, 2.0 g, 1.0 equiv), and 20 mL H 2 O:Et 2 O (1:1) [18][19][20] .…”

Section: (3s)-3-(4-iodobenzyl)-6-methyl-14-dioxane-25-dione (3)mentioning

confidence: 99%

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Iodinated Polyesters with Enhanced X-ray Contrast Properties for Biomedical Imaging

Lex

Brummel

Attia

et al. 2020

Sci Rep

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Synthetic materials exhibiting contrast imaging properties have become vital to the field of biomedical imaging. However, polymeric biomaterials are lacking imaging contrast properties for deep tissue imaging. this report details the synthesis and characterization of a suite of aryl-iodo monomers, which were used to prepare iodinated polyesters using a pre-functionalization approach. commercially available 4-iodo-phenylalanine or 4-iodobenzyl bromide served as the starting materials for the synthesis of three iodinated monomeric moieties (a modified lactide, morpholine-2,5-dione, and caprolactone), which under a tin-mediated ring-opening polymerization (Rop), generated their respective polyesters (pe) or poly(ester amides) (peA). An increase in X-ray intensity of all synthesized iodine-containing polymers, in comparison to non-iodinated poly(lactic acid) (pLA), validated their functionality as radio-opaque materials. the iodinated-poly(lactic acid) (ipLA) material was visualized through varying thicknesses of chicken tissue, thus demonstrating its potenial as a radio-opaque biomaterial. Medical imaging, a technique that provides structural visualization inside the body, aides in the study of specific morphological changes within living and nonliving systems 1,2. One particular imaging modality, X-ray radiography, is frequently used as a diagnostic tool for non-invasive, in vivo, real-time examinations of three-dimensional opaque objects. X-ray imaging can be used to monitor response, degradation, and defects of biomedical devices 3. Concerns over the long-term stability of prolonged or permanent implantable devices have led to the development of polyester-based materials due to their desirable properties (i.e. biocompatibility, biodegradability, and facile synthesis) 4-8. The evolution of biodegradable polyester devices, like staples, stents, sutures, and implants, have had a significant impact on the biomedical field 4,9,10. Perhaps the most noteworthy advantage is their ability to be degraded and excreted from the body, obviating the need for their removal or surgical revision. This can be vital in major surgical procedures such as fracture fixation, spinal fixation, and abdominal wall repair 4,10. While commercially available polyester devices have seen a considerable amount of use in the biomedical field, their in vivo performance can be difficult to predict and evaluate due to the complex biological environment associated with tissues 10,11. Therefore, the real-time monitoring of these devices is critical in order to understand their performance and fate in the body. The major drawback of polyester-based devices is that they lack inherent contrast imaging properties, making it difficult to visualize the area of interest. Imaging techniques are useful only when the intensity of a signal is sufficient enough to distinguish the target from surrounding tissues or materials. This issue becomes even more evident when imaging materials through deep tissue or when monitoring minor defects in biomaterials 12. Recent ...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Iodinated Polyesters with Enhanced X-ray Contrast Properties for Biomedical Imaging

Lex

Brummel

Attia

et al. 2020

Sci Rep

Self Cite

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“…Additionally to CS, for the preparation of skin patches, several polymeric biodegradable materials have been utilized until now (either alone or in combination with other suitable carriers), including poly(amides), poly(amino acids), poly(alkyl-a-cyano acrylates), poly(esters), poly(orthoesters), poly(urethanes), and poly (acrylamides) [ 18 , 19 , 20 ]. Amongst them, aliphatic polyesters (prepared from either lactic or glycolic acid, or a combination of them) are probably the most widely used polymeric materials for this reason [ 21 , 22 , 23 ]. Specifically, poly(l-lactic acid) (PLLA), a biodegradable thermoplastic polyester derived from renewable plant sources, such as starch and sugar, is an extensively used in biomedical applications and especially in the preparation of dermal or transdermal formulations due to its unique characteristics (such as slow degradation, good adhesion, elasticity, etc.)…”

Section: Introductionmentioning

confidence: 99%

Leflunomide Loaded Chitosan Nanoparticles for the Preparation of Aliphatic Polyester Based Skin Patches

et al. 2021

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In the present study, the preparation of controlled-released leflunomide (LFD)-loaded skin patches was evaluated, utilizing the combination of chitosan (CS) nanoparticles (NPs) incorporated into suitable poly(l-lactic acid) (PLLA) or poly(lactic-co-glycolic acid) (PLGA) polyester matrices. Initially, LFD-loaded CS NPs of ~600 nm and a smooth surface were prepared, while strong inter-molecular interactions between the drug and the CS were unraveled. In the following step, the prepared LFD-loaded CS NPs were incorporated into PLLA or PLGA, and thin-film patches were prepared via spin-coating. Analysis of the prepared films showed that the incorporation of the drug-loaded CS NPs resulted in a significant increase in the drug’s release rate and extent as compared to neat LFD-loaded polyester patches (i.e., prepared without the use of CS NPs). In-depth analysis of the prepared formulations showed that the amorphization of the drug within the matrix and the increased wetting properties of the prepared CS NPs were responsible for the improved thin-film patch characteristics.

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“…Dental implants have been commendably and effectively used in recent years to treat missing teeth owing to their long-term clinical success rate [1][2][3]. Although the success rate of dental implant therapy is high, the healing mechanism between the alveolar bone and the titanium implant fixture was replaced with osseointegration [4].…”

Section: Introductionmentioning

confidence: 99%

Relationships of Stresses on Alveolar Bone and Abutment of Dental Implant from Various Bite Forces by Three-Dimensional Finite Element Analysis

Kang

Wang

et al. 2020

BioMed Research International

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Occlusal trauma caused by improper bite forces owing to the lack of periodontal membrane may lead to bone resorption, which is still a problem for the success of dental implant. In our study, to avoid occlusal trauma, we put forward a hypothesis that a microelectromechanical system (MEMS) pressure sensor is settled on an implant abutment to track stress on the abutment and predict the stress on alveolar bone for controlling bite forces in real time. Loading forces of different magnitudes (0 N–100 N) and angles (0–90°) were applied to the crown of the dental implant of the left central incisor in a maxillary model. The stress distribution on the abutment and alveolar bone were analyzed using a three-dimensional finite element analysis (3D FEA). Then, the quantitative relation between them was derived using Origin 2017 software. The results show that the relation between the loading forces and the stresses on the alveolar bone and abutment could be described as 3D surface equations associated with the sine function. The appropriate range of stress on the implant abutment is 1.5 MPa–8.66 MPa, and the acceptable loading force range on the dental implant of the left maxillary central incisor is approximately 6 N–86 N. These results could be used as a reference for the layout of MEMS pressure sensors to maintain alveolar bone dynamic remodeling balance.

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Recent Advances in Polyesters for Biomedical Imaging

Cited by 27 publications

References 84 publications

Iodinated Polyesters with Enhanced X-ray Contrast Properties for Biomedical Imaging

Iodinated Polyesters with Enhanced X-ray Contrast Properties for Biomedical Imaging

Leflunomide Loaded Chitosan Nanoparticles for the Preparation of Aliphatic Polyester Based Skin Patches

Relationships of Stresses on Alveolar Bone and Abutment of Dental Implant from Various Bite Forces by Three-Dimensional Finite Element Analysis

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