Browsing by Subject "Xenon difluoride"

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A high-precision method for manufacturing tunable solid microneedles using dicing saw and xenon difluoride-induced dry etching
(Elsevier BV, 2023-12-19) Eş, İsmail; Kafadenk, Abdullah; İnci, Fatih
Numerous fabrication techniques have been employed to produce solid microneedles (MNs); yet precise manufacturing of MNs with adjustable features (height, aspect ratio, and array number) remains the main limitation. Developing tunable MNs holds immense promise for personalized and efficient drug delivery systems. In this study, we utilized a combination of dicing saw and XeF2 isotropic dry etching processes to fabricate solid MNs with tunable characteristics. We herein created rectangular arrays using a dicing saw with desired geometry followed by dry etching to form MN arrays without further processing. Employing optimized parameters, the average heights of the MNs were 522 +/- 15 mu m, 614 +/- 42 mu m, and 698 +/- 22 mu m for initial pattern depths of 500 mu m, 600 mu m, and 700 mu m, respectively. Moreover, we achieved an aspect ratio as high as 3.7, a radius of curvature less than 10 mu m, and a tip angle as low as 6.4(o). The mechanical and surface properties of the MNs were enhanced through magnetron sputtering with titanium. An ex vivo penetration test conducted on porcine skin demonstrated the significant potential of these MNs for transdermal drug delivery in future investigations. Overall, a cost-effective production of a single solid MN patch, featuring 400 MN arrays per cm(2), can be achieved within a remarkably short timeframe (approximately 2 h). Investigating fundamental principles, this study addresses the persistent challenge in manufacturing solid MNs with adjustable features, such as height, aspect ratio, and array number. This presents a substantial advantage over alternative fabrication techniques.
Open Access
Xenon difluoride dry etching for the microfabrication of solid microneedles as a potential strategy in transdermal drug delivery
(Wiley-VCH Verlag GmbH & Co. KGaA, 2023-07-23) Eş, İsmail; Kafadenk, Abdullah; Görmüş, M. Burak; İnci, Fatih
Although hypodermic needles are a “gold standard” for transdermal drug delivery (TDD), microneedle (MN)-mediated TDD denotes an unconventional approach in which drug compounds are delivered via micron-size needles. Herein, an isotropic XeF2 dry etching process is explored to fabricate silicon-based solid MNs. A photolithographic process, including mask writing, UV exposure, and dry etching with XeF2 is employed, and the MN fabrication is successfully customized by modifying the CAD designs, photolithographic process, and etching conditions. This study enables fabrication of a very dense MNs (up to 1452 MNs cm−2) with height varying between 80 and 300 µm. Geometrical features are also assessed using scanning electron microscopy (SEM) and 3D laser scanning microscope. Roughness of the MNs are improved from 0.71 to 0.35 µm after titanium and chromium coating. Mechanical failure test is conducted using dynamic mechanical analyzer to determine displacement and stress/strain values. The coated MNs are subjected to less displacement (≈15 µm) upon the applied force. COMSOL Multiphysics analysis indicates that MNs are safe to use in real-life applications with no fracture. This technique also enables the production of MNs with distinct shape and dimensions. The optimized process provides a wide range of solid MN types to be utilized for epidermis targeting.