Agui-Lab Projects

Laser-induced periodic surface nanostructures for enhanced surface functionalities.

Nanostructured surfaces play a crucial role in optics, tribology, medicine, and energy harvesting. Common techniques involve chemical and plasma etching, vapor deposition, sputtering, and lithography. However, these methods are costly, time-consuming, and often limited to semiconductors. An economical alternative is laser-induced periodic surface structures (LIPSS), or nanoripples, formed on various materials with linearly polarized ultrafast laser pulses, offering a cost-effective solution for nanostructuring.

Variable exposure laser speckle imaging using commercially available Systems on Modules towards portable perfusion monitoring

Laser Speckle Imaging (LSI) is crucial for blood flow imaging in biomedical research. This study uses NVIDIA’s Xavier NX for variable exposure LSI, assessing flow rates in a 3D-printed flow phantom. A Raspberry Pi HQ camera enables rapid image capture (<1 ms exposure time). The Xavier NX’s high performance allows distinguishing slow, medium, and fast flow rates, making it suitable for portable LSI devices in various medical applications.

Digital Holography Interferometry: A Tool to Characterize Thermophysical Properties of Water, Cryoprotectants, and Biological Systems During Vitrification and Rewarming to Improve Viability Post Preservation

Vitrification is a rapid method for cryopreserving biological samples without ice formation, preventing mechanical damage. While effective for small samples like cells and embryos, achieving critical cooling rates, the rewarming stage poses challenges. To address this, a solution involves dispersing plasmonic nanomaterials in cryoprotective agents, enabling rapid heat conversion with a laser beam during rewarming, overcoming slow conduction warming and avoiding devitrification.

Laser-induced cavitation bubble dynamics close to periodic surface microstructures

A high-energy laser pulse focused into a liquid induces laser-induced cavitation, leading to plasma formation and shockwave emission. The dynamics of cavitation bubbles near surfaces, particularly flat and rigid ones, have been extensively studied to minimize damage in nautical equipment. Solid boundaries attract cavitation bubbles, causing toroidal-shaped collapses. Research has expanded to include various boundary types, such as edges, parallel walls, microfluidics, and elastic surfaces, with potential applications in microfluidics and surface cooling.

Thermal characterization during cryopreservation and rewarming via digital holography interferometry

Vitrification is a rapid approach to cryopreserve biological samples without ice formation, which induces mechanical injury to the specimen. However,

developing vitrification technologies for biological systems in the μL – L scale is challenging due to non-uniform cooling/warming and cryoprotectant (CPA) toxicity. Additionally, there are current limitations of monitoring in real-time CPA distribution, temperature, and phase changes to develop cryopreservation protocols. Therefore, real-time monitoring of these parameters is a necessity to make advancements in the field of cryopreservation. This project entails developing and utilizing an optical tool, digital holography interferometry (DHI), to perform in-situ thermal analysis of water, CPAs, and biological systems to improve vitrification protocols which can lead to enhanced specimen viability post preservation.