Zirconia is a material that mimics human teeth and has been extensively studied and applied. This study investigated the surface modifications of dental zirconia induced by two UV-C wavelengths (222 and 254 nm). A total of 72 zirconia specimens were prepared and divided into groups for irradiation at varying distances (1, 6, 12 cm) and durations (40, 120, 480 and 1440 min), with three specimens retained as untreated controls. Surface changes were assessed by measuring colour difference (ΔE) and water contact angle, and by analyzing surface morphology and elemental composition using SEM and EDX, and XRD was employed to determine the crystalline structure. The results showed that both wavelengths induced clinically perceptible colour changes (ΔE > 2.0), with the most pronounced effect at 6 cm for 222 nm and 1 cm for 254 nm. WCA decreased significantly with irradiation time, showing a linear correlation with log(time), and 222 nm irradiation yielded lower WCA than 254 nm. While SEM revealed no morphological changes, both UV treatments significantly increased the Zr/O ratio compared to the control. XRD tests confirmed that UV-C irradiation does not damage the zirconium oxide crystal structure. It is concluded that both UV-C wavelengths can alter the colour and enhance the wettability of zirconia; these modifications are particularly relevant for dental restorative applications, specifically in the fabrication of anterior tooth crowns, where achieving a natural tooth-like appearance is desired.

A common complication of the removal of atherosclerotic plaques or thrombi deposits to restore blood flow is restenosis. It is known that the excessive adhesion and proliferation of smooth muscle cells (SMCs) is the primary reason for restenosis. In this work, we conducted an in vitro study to show that a weak oscillating electric field (EF) generated by a mechanically-driven nanogenerator could prohibit SMC adhesion and proliferation on a substrate surface. Our results revealed a decrease in the cell number when an oscillating EF was introduced underneath the substrate. The cell coverage was found to be dependent on the EF strength and oscillating frequency, where higher EF strength and frequency yielded a stronger inhibitory effect. Compared to the control, this reduction in cell coverage reached up to 54% under the optimal EF parameters. This inhibitory effect was attributed to the EF-induced surface charge oscillation, which weakened the electrostatic interaction between the cell membrane and substrate. Our discovery suggests the potential for self-powered anti-restenosis solutions by integrating NG-induced oscillating EFs with biomedical device surfaces.

Leadless intracardiac pacemakers (LIP) are a technological breakthrough that offer tremendous benefits to patients, including minimally invasive delivery, improved quality of life, and reduced financial burden. However, limited by its size and capacity, the battery component becomes a major roadblock to further advancing LIP technology toward lifelong, maintenance-free implants without the need for device retrieval or replacement. Here, we present an integrated, nanogenerator-powered LIP with a clinically compatible architecture. The LIP is solely powered by a double-oscillatory triboelectric nanogenerator (TENG) that is capable of generating a volumetric power density of 276.6 μW cc ⁻¹ driven by heartbeats. The miniaturized TENG can also fit within the battery compartment of a commercial Medtronic Micra LIP, allowing standard femoral-venous delivery by commercial catheters. When implanted in the heart of a swine model, the device delivers stable, rate-responsive electrical energy in vivo, which reliably supports the cardiac pacing function for heart rates control at physiological levels through harvested energy. Long-term intracardiac implantation further confirmed secure fixation, unaffected cardiac function and minimal tissue reaction of the fully integrated device. This development suggests a clinically compatible path toward self-sustainable intracardiac electronic systems.