Solder doped polycaprolactone scaffold enables reproducible laser tissue soldering

Abstract

Background and Objectives: In this in vitro feasibility study we analyzed tissue fusion using bovine serum albumin (BSA) and Indocyanine green (ICG) doped polycaprolactone (PCL) scaffolds in combination with a diode laser as energy source while focusing on the influence of irradiation power and albumin concentration on the resulting tensile strength and induced tissue damage. Materials and Methods: A porous PCL scaffold doped with either 25% or 40% (w/w) of BSA in combination with 0.1% (w/w) ICG was used to fuse rabbit aortas. Soldering energy was delivered through the vessel from the endoluminal side using a continuous wave diode laser at 808 nm via a 400 mm core fiber. Scaffold surface temperatures were analyzed with an infrared camera. Optimum parameters such as irradiation time, radiation power and temperature were determined in view of maximum tensile strength but simultaneously minimum thermally induced tissue damage. Differential scanning calorimetry (DSC) was performed to measure the influence of PCL on the denaturation temperature of BSA. Results: Optimum parameter settings were found to be 60 seconds irradiation time and 1.5 W irradiation power resulting in tensile strengths of around 2,000 mN. Corresponding scaffold surface temperature was 117.4 AE 128C. Comparison of the two BSA concentration revealed that 40% BSA scaffold resulted in significant higher tensile strength compared to the 25%. At optimum parameter settings, thermal damage was restricted to the adventitia and its interface with the outermost layer of the tunica media. The DSC showed two endothermic peaks in BSA containing samples, both strongly depending on the water content and the presence of PCL and/or ICG. Conclusions: Diode laser soldering of vascular tissue using BSA-ICG-PCL-scaffolds leads to strong and reproducible tissue bonds, with vessel damage limited to the adventitia. Higher BSA content results in higher tensile strengths. The DSC-measurements showed that BSA denaturation temperature is lowered by addition of water and/or ICG-PCL. Lasers Surg. Med. 40:716-725, 2008. ß

Focused Arterial Anastomotic Assessment in a Novel Univariate Design of a Vertical Rectus Abdominis Muscle Flap in a Pig Model

“…New developments in laser anastomosis are being developed, which require a laser probe to be inserted into the artery. 19,20 This has previously tried through cannulating side branches of the artery; however, this is often difficult due to the size and location of appropriate arteries. With the design of the VRAM flap in this study, it is possible to cannulate the DIEA and pass the probe proximally through the entire length of the flap until it emerges at the divided DSEA.…”

Laser-assisted vessel welding: state of the art and future outlook

“…Furthermore, the flexibility of the scaffold is more favorable for vascular applications than solid solder films [58]. ssLAVW comprises the use of a polymeric scaffold to enhance cohesive bonding of the liquid solder during sLAVW [93][94][95][96][97][98][99][100][101][102][103]108]. A semi-porous scaffold composed of biocompatible polymeric material is drenched in chromophore-containing solder, placed over the coaptation, and irradiated.…”

“…In (B) ssLAVR was performed with a 50% BSA solder, poly(lactic-co-glycolic acid) (PLGA) scaffolds, and an 806-nm diode laser [102]. SsLAVR in (A) was performed on porcine carotid arteries [97], whereas in (B) ssLAVR was performed on porcine [102] and rabbit aortic strips [94,100]. The numbers in brackets indicate the reference from which the data were obtained.…”

“…phore concentrations as a function of welding strength, respectively. The majority of ssLAVW studies were performed in vitro as ssLAVR of small-and medium-sized vessels and used either a 670-nm or an 806-810-nm diode laser [86,[93][94][95][96][97][98][99][100][101][102][103]. Figure 9 shows the improvement in welding strength with increasing power and irradiance.…”

“…Figure 11 demonstrates the influence of solder composition and the scaffold's thermo-mechanical properties on acute and post-hydration welding strength. As with sLAVR, a higher solder protein concentration produced stronger repairs than lower protein concentrations [91,93,94,98,102,103,104]. The reduction in solder leakage was achieved by semi-solidification of the solder.…”