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Novel Biodegradable Polymer Tethered Platinum (II) for Photoacoustic Imaging
摘要： Photoacoustic microscopy (PAM) is an emerging imaging diagnostic technique for various diseases. Coupled with contrast agents, photoacoustic (PA) imaging yields additional information to facilitate an accurate diagnosis. While many organic-based contrast agents, notably those of cyanine dyes, nanoparticles, polyhydroxy-fullerene and carbon nanotubes, have become available, the use of transition metal as contrast agent is scant. Here, for the first time, we report a platinum II-based biodegradable polymer for PA imaging that is capable of effective cellular internalization with very low cytotoxicity. The experiment results show great promise as a novel photoacoustic contrast agent as its detectable PA signal was observed both in cell imaging and in vivo rat cerebral vascular imaging via designed PAM. This work exemplifies the incorporation of transition metal complex with polymeric nanoparticles, further expanding the field of the ability of PA imaging.
关键词： Platinum,Biodegradable polymer,Photoacoustic imaging,Contrast agent,Transition metal
更新于2025-09-23 15:21:21
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Incidence of late-acquired stent malapposition of drug eluting stents with second generation permanent and biodegradable polymer coatings-A prospective, randomized comparison using optical coherence tomography
摘要： Objectives and Background: Polymer coatings of drug-eluting stents (DES) may induce allergic reactions and inflammation, resulting in late-acquired stent malapposition (LASM) with the risk of stent thrombosis. This study evaluated, if biodegradable polymer (BP) reduces the incidence of LASM compared to permanent polymer (PP) after treatment with newer generation DES. Methods and Results: Fifty patients with 59 lesions were randomized (2:1) to elective treatment with second generation PP-DES (n = 32, 39 stents), either Everolimus-eluting or Zotarolimus-eluting stents, or with BP-DES (Biolimus-eluting stents [BES]; n = 18, 20 stents) and underwent optical coherence tomography directly after implantation and after 1 year. After implantation acute stent malappositions (ASM) were documented in 30 stents (51%) distributed to 22 stents treated with PP-DES (56%) and 8 with BP-DES (40%; n.s.). After 1 year, late stent malappositions (LSM) were detected in 14 stents (24 %); ASM persisted (APSM) in 9 stents after one year (7 PP-DES—18%, 2 BES—10%), whereas ASM resolved in 21 stents. In addition, LASM was documented in nine stents including five stents without and four stents with additional APSM. All LASM were located in PP-DES (n = 9; 23%), none in BP-DES (P = 0.022). Compared to the reference lumen area, in-stent lumen area of stents without LASM was smaller due to neointimal hyperplasia (P = 0.021), whereas in-stent lumen area at maximum LASM of stents with LASM was larger due to positive remodeling (P = 0.002). Conclusions: In conclusion the use of BP-DES reduced the occurrence of LASM due to positive remodeling compared to second generation PP-DES.
关键词： malapposition,permanent polymer,drug eluting stents,optical coherence tomography,biodegradable polymer
更新于2025-09-23 15:21:01
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Study of Physical and Degradation Properties of 3D-Printed Biodegradable, Photocurable Copolymers, PGSA-co-PEGDA and PGSA-co-PCLDA
摘要： As acrylated polymers become more widely used in additive manufacturing, their potential applications toward biomedicine also raise the demand for biodegradable, photocurable polymeric materials. Polycaprolactone diacrylate (PCLDA) and poly(ethylene glycol) diacrylate (PEGDA) are two popular choices of materials for stereolithography (SLA) and digital light processing additive manufacturing (DLP-AM), and have been applied to many biomedical related research. However, both materials are known to degrade at a relatively low rate in vivo, limiting their applications in biomedical engineering. In this work, biodegradable, photocurable copolymers are introduced by copolymerizing PCLDA and/or PEGDA with poly(glycerol sebacate) acrylate (PGSA) to form a network polymer. Two main factors are discussed: the effect of degree of acrylation in PGSA and the weight ratio between the prepolymers toward the mechanical and degradation properties. It is found that by blending prepolymers with various degree of acrylation and at various weight ratios, the viscosity of the prepolymers remains stable, and are even more 3D printable than pure substances. The formation of various copolymers yielded a database with selectable Young’s moduli between 0.67–10.54 MPa, and the overall degradation rate was significantly higher than pure substance. In addition, it is shown that copolymers fabricated by DLP-AM fabrication presents higher mechanical strength than those fabricated via direct UV exposure. With the tunable mechanical and degradation properties, the photocurable, biodegradable copolymers are expected to enable a wider application of additive manufacturing toward tissue engineering.
关键词： additive manufacturing,poly(glycerol sebacate) acrylate,photocurable polymer,poly(ethylene glycol) diacrylate,digital light processing,polycaprolactone diacrylate,biodegradable polymer
更新于2025-09-09 09:28:46