Analysis of penetration depth and healing process of a needleless laser lancet using swept-source optical coherence tomography

Abstract

Background and objectives: Needleless laser lancets have been used to reduce needle pain in people who undertake self-monitoring of blood glucose (SMBG). Although clinical trials have been conducted to understand the degree of pain associated with the developed laser blood sampling device, it is only judged by the patients' subjective judgment. This study aimed to analyze the performance and healing process of a needleless laser lancet. In particular, the penetration depth and healing process of a conventional lancet and a needleless laser lancet were quantitatively analyzed using a swept-source optical coherence tomography (SS-OCT) system.

Materials and methods: To reduce unnecessary animal sacrifice, pig skin was used to establish and set the conditions for needleless laser lancets (wavelength of 2.94 μm; LMT-5000; Lameditech), and the penetration depth and healing process were quantitatively assessed at 0, 6, 9, and 16 h after laser (energy, 150-270 mJ in stages; voltage, 7.4 V_dc ; pulse width, approximately 200 microsecond) irradiation using 7-week-old male BALB/c nude mice. The penetration depth and healing process were measured using homemade SS-OCT, and histopathological examination was performed to observe the healing process.

Results: Four 7-week-old male BALB/c nude mice were tested at intensity levels of 1-3 using a needleless laser lancet and compared with the experimental values using a conventional lancet. After the lancet test, the diameter and depth of the puncture were measured using SS-OCT and the healing process was confirmed using SS-OCT and pathological slides. The puncture diameter of the needleless laser lancet was about 0.5 mm regardless of the level. In addition, the average depths at Levels 1, 2, and 3 of the measured needleless laser lancet were approximately 1.05, 1.18, and 1.52 mm, respectively, and the last common lancet was approximately 0.9 mm. In addition, the healing process of the needleless laser lancet and conventional lancet was confirmed through the SS-OCT system.

Conclusion: After using the needleless laser lancet, quantitative indicators such as the diameter of puncture, penetration depth, and healing process were confirmed through two-dimensional and three-dimensional images of the homemade SS-OCT system and microscopic imaging of pathological slides.

Keywords: glucose measurement; needleless laser lancet; optical coherence tomography.