Researchs & Projects

Laser-Patterned Diamond Electrodes for Adhesion and Proliferation of Human Mesenchymal Stem Cells

The ability to form diamond electrodes on insulating polycrystalline diamond substrates using single-step laser patterning and the use of these electrodes as a substrate that supports the adhesion and proliferation of human mesenchymal stem cells (hMSCs) are demonstrated. Laser-induced graphitization results in a conductive amorphous carbon surface, rich in oxygen- and nitrogen-terminated groups. This leads to an electrode with a high specific capacitance of 182 μF cm2, a wide water window of 3.25 V, and a low electrochemical impedance of 129 Ω cm2 at 1 kHz—essential attributes for effective bioelectronic cell interfaces. The electrode's surface exhibits no cytotoxic responses with hMSCs, supporting cell adhesion and proliferation. Cells cultured on the electrode display significant elongation and alignment along the direction of the laser-patterned microgrooves—an additional modality for cellular modulation. The combination of favorable electrochemical performance and effective cellular control makes laser-patterned diamond electrodes a versatile platform in stem cell therapeutics. This direct fabrication approach paves the way for the integration of diamond electrodes in bioelectronic devices, offering new opportunities for tissue engineering and electroactive biomaterial applications.

Ph.D. RESEARCH PROJECT (Diamond photoelectrodes using laser writing defects)

This project introduces a new approach for creating diamond photoelectrodes that respond to sub-band illumination. Then, employing ns and fs laser writing techniques to locally introduce disorder within the diamond crystals. Also, by utilising surface treatments techniques, the surface defects of the diamond electrodes are restructured, leading to enhanced photoelectrodes performance. The photoelectrochemical properties of the electrodes are investigated and combined with XPS, Raman and UPS to describe the physical processes. Responsivity to VIS-NIR range opens up diamond, with its host of attractive biological and chemical attributes, to a myriad of applications. Using laser writing method enables seamless integration of the photoelectrodes with other optical structures on the diamond.

M.Eng. RESEARCH PROJECT (Laser Writing of Color Centers in h-BN and w-GaN)

(Mar 2018 – Dec 2018): The research project is a theoretical study accompanied by experimental analysis of the effects of femtosecond laser exposures in modifying the optical and electrical properties of Hexagonal Boron nitride (h-BN) and Wurtzite Gallium nitride (w-GaN). Point-Defects were fabricated successfully in both w-GaN and h-BN using the laser writing method. Photoluminescence mapping, photon count rate, and photoluminescence spectra measurements were performed for different laser writing pulse energies. This type of research in wide-bandgap semiconductors is useful in different types of sensory applications and quantum information, computing and optics.

B.S. SENIOR PROJECT (Solar Car Project: Body Design & Manufacturing)

(Dec 2010 - Oct 2011): In eleven months, Seraaj team designed and built the first Saudi solar car called ‘Wahj’. The shape of the solar car was designed by selecting an appropriate airfoil. Then, aerodynamic analysis was performed on the body shape. Also, a 3D model of the body was produced using a CAD program (Solidworks). Then, the 3D model was used to manufacture the plug using the milling and CNC machine. As manufacturing the body, several types of Fibre-reinforced Polymers (FRP) were used. First, the body plug was created using fibreglass. Then, for the body itself, a prepreg carbon fibre was used for the lower part and Kevlar for the upper part. The project was successfully completed, and the team participated with Wahj in the “World Solar Challenge”, which was conducted in Australia in 2011.

Enhanced electrochemical capacitance of nitrogen-doped ultrananocrystalline diamond through oxygen treatment

S. Falahatdoost, A. Chambers, A. Stacey, H. N. Al Hashem, A. Nadarajah, S. Prawer, and A. Ahnood, “Enhanced electrochemical capacitance of nitrogen-doped ultrananocrystalline diamond through oxygen treatment,” Applied Surface Science, vol. 543, p. 148768, 2021

The electrochemical capacitance of nitrogen-doped ultrananocrystalline diamond (N-UNCD) can be dramatically increased by treating the surface with an RF-oxygen plasma. Such treated surfaces display excellent properties for use as electrodes in neural stimulation and recording. In the present work, we elucidate the origins of this phenomenon by investigating the effects of different methods of oxygen termination. We found that the increase in electrochemical capacitance is dependent on the details of the method used for oxygen termination. Whilst N-UNCD subjected to UV/ozone treatment, oxygen plasma treatment, and furnace annealing in oxygen gas all displayed increased surface capacitance, the highest capacitance was exhibited by the oxygen annealed sample, with which we achieved ~ 3 orders of magnitude increase in the electrochemical capacitance as compared to the as-grown sample.