Raman Spectroscopic Characterization of Polymerization Kinetics of Cyanoacrylate Embolic Glues for Vascular Embolization

Abstract

Endovascular glue embolization is a minimally invasive technique used to selectively reduce or block the blood supply to specific targeted vessels. Cyanoacrylate glues, mixed with radiopaque iodized oil, have been widely used for vascular embolization owing to their rapid polymerization rate, good penetration ability and low tissue toxicity. Nevertheless, in clinical practice, the selection of the glue–oil proportion and the manual injection process of mixtures are mostly based on empirical knowledge of operators, as the crucial physicochemical effect of polymerization kinetics has rarely been quantitatively investigated. In this study, the Raman spectroscopy is used for studying the polymerization kinetics of n-butyl-cyanoacrylate-based glues mixed with an iodized oil. To simulate the polymerization process during embolization, glue–oil mixtures upon contact with a protein ionic solution mimicking blood plasma are manually constructed and their polymerization kinetics are systematically characterized by Raman spectroscopy. The results demonstrate the feasibility of Raman spectroscopy in the characterization of polymerization kinetics of cyanoacrylate-based embolic glues. The polymerization process of cyanoacrylate-based mixtures consists of a fast polymerization phase followed by a slow phase. The propagation velocity and polymerization time primarily depend on the glue concentrations. The commonly used 50% mixture polymerizes 1 mm over ∼21.8 s, while it takes ∼51 min to extend to 5 mm. The results provide essential information for interventional radiologists to help them understand the polymerization kinetics of embolic glues and thus regulate the polymerization rate for effective embolization.

On the Development of Ultradurable Extremely Water-Repellent and Oleophobic Soot-Based Fabrics with Direct Relevance to Sperm Cryopreservation

“…44,58,66 On the other hand, the peaks at 2250 and 2900 cm −1 correspond to the stretching vibration of the triple carbon− nitrogen bond and symmetry/asymmetry stretching vibrations of C−H bonds in the acryl and methyl groups of the cured cyanoacrylate. 65 Expectedly, the latter enhances the amorphousness of soot-coated fabrics, detected by the increased I D1 /I G ratio (I D1 /I G ∼ 1.04−1.05) in comparison with the pristine soot (I D1 /I G ∼ 0.98). 58 It is pertinent to mention that the I D1 /I G ratios are calculated by extracting the intensities at ∼1350 and 1590 cm −1 .…”

“…64 As seen in Figure 7, the Raman spectroscopy of samples 4 and 6 recognizes four prominent peaks located at ∼1350, 1590, 2250 and 2900 cm −1 , linked to the D 1 -band and G-band of disordered graphite, as well as the C�N and C−H bonds of cyanoacrylate. 44,58,65,66 The G-band reflects the E 2g vibration mode of crystalline graphite, whereas the D 1 -band is "forbidden" and appears only in the presence of amorphous structures activating the A 1g symmetry vibration mode. 44,58,66 On the other hand, the peaks at 2250 and 2900 cm −1 correspond to the stretching vibration of the triple carbon− nitrogen bond and symmetry/asymmetry stretching vibrations of C−H bonds in the acryl and methyl groups of the cured cyanoacrylate.…”

X-ray Microtomography to Assess Determinants of In Vivo N-Butyl Cyanoacrylate Glubran®2 Polymerization: A Rabbit-Model Study

“…We chose rabbits because they share with rodents the advantages of small size, ease of handling and housing, and relatively low cost compared to swine [ 15 , 29 , 30 ]. The species taking account corresponding coagulation parameters and vessel size may not substantially affect the behavior of NBCA mixtures, since polymerization is initiated and propagated by anions present in all mammals [ 18 , 31 , 32 ]. Note that polymerization and subsequent vessel occlusion can occur even in anticoagulated blood.…”

Iodixanol as a New Contrast Agent for Cyanoacrylate Embolization: A Preliminary In Vivo Swine Study

“…In two swine studies, at least a 1/6th proportion of iopamidol was required to prevent adhesion within the microcatheter, and the optimal NBCA-LUF-iopamidol ratio was 2/3/1 [16][17][18]. Although iopamidol is a low-osmolar agent, iodixanol is iso-osmolar and might, therefore, be expected to cause a greater delay in NBCA polymerization and, therefore, greater distality of penetration [6,7,19]. To our knowledge, no in vivo study of NBCA mixed with iodixanol for embolization procedures has been published.…”