RESUMEN
A series of derivatives (DOCD2-DOCD6) with D-π-A configuration was designed by substituting various efficient donor moieties via the structural tailoring of o-DOC6-2F. Quantum-chemical approaches were used to analyze the optoelectronic properties of the designed chromophores. Particularly, M06/6-311G(d,p) functional was employed to investigate the non-linear optical (NLO) response (linear polarizability ⟨α⟩, first (ßtot) and second ([Formula: see text]tot) order hyperpolarizabilities) of the designed derivatives. A variety of analyses such as frontier molecular orbital (FMO), absorption spectra, transition density matrix (TDMs), density of states (DOS), natural bond orbital (NBO) and global reactivity parameters (GRPs) were employed to explore the optoelectronic response of aforementioned chromophores. FMO investigation revealed that DOCD2 showed the least energy gap (1.657 eV) among all the compounds with an excellent transference of charge towards the acceptor from the donor. Further, DOS pictographs and TDMs heat maps also supported FMO results, corroborating the presence of charge separation states along with efficient charge transitions. NBO analysis showed that π-linker and donors possessed positive charges while acceptors retained negative charges confirming the D-π-A architecture of the studied compounds. The λmax values of designed chromophores (659.070-717.875 nm) were found to have broader spectra. The GRPs were also examined utilizing energy band gaps of EHOMO and ELUMO for the entitled compounds. Among all the derivatives, DOCD2 showed the highest values of ßtot (7.184 × 10-27 esu) and [Formula: see text]tot (1.676 × 10-31 esu), in coherence with the reduced band gap (1.657 eV), indicating future potentiality for NLO materials.
RESUMEN
BACKGROUND: Benign biliary strictures (BBS) are widely treated by endoscopic procedures involving temporary stent placement. Occasionally, stents are required to be removed, making the treatment process very painful as well as expensive. Until now, no effective biodegradable biliary stents are available for clinical applications. This study aims to investigate the safety and efficacy of biodegradable polydioxanone (PDO) and polylactic acid (PLA) braided biodegradable biliary stents (BDBS) both in vitro and in vivo. METHODS: Three different diameter monofilaments of PDO (0.30, 0.35, and 0.40 mm) and PLA (0.10, 0.15, and 0.20 mm) were braided to biliary stents and their mechanical properties were studied. The stents were placed in an ex vivo bile duct model perfused with porcine bile, taken out, and observed every week until these were completely degraded. After the bile duct stenosis model was established successfully in piglet, stents with appropriate mechanical properties were further examined under endoscopy; haematology, patency time of stents, and pathological changes were observed for eight months. RESULTS: A total of 10 pigs were included (two groups; 5 PDO, 5 PLA) in the study. The patency time of the PLA group was significantly longer than that of the PDO stent group (25.7 ± 5.6w vs 11.3 ± 3.4w, respectively) in pigs. CONCLUSION: Our results prospect biodegradable PLA and PDO braided biliary stents could be a better choice to treat benign biliary strictures while degrading at different rates.
