Khalil Moussi - Academia.edu (original) (raw)

Papers by Khalil Moussi

2019 IEEE 14th International Conference on Nano/Micro Engineered and Molecular Systems (NEMS), 2019

A miniaturized 3D printed drug delivery device powered wirelessly is presented. The device is com... more A miniaturized 3D printed drug delivery device powered wirelessly is presented. The device is composed of an electrochemical micropump, a 3D printed reservoir with microneedles, and a wireless powering unit. The electrochemical pump features an expandable (up to 300%) Parylene C microbellows membrane fabricated by mold casting, using a twophoton polymerization 3D printing technique. The hollow microneedles are 100 µm in diameter and 300 µm long. The fabrication process offers customizable device properties, where the shape, size, and performance can be tailored to fit a wide range of in vivo drug delivery applications. Delivery of 3.8 ± 0.3 µL within 10 seconds of actuation is demonstrated, using inductive wireless powering at a distance of 10 mm between the primary and secondary coils.

2022 IEEE International Conference on Consumer Electronics (ICCE), 2022

This paper presents an impedimetric biosensor for monitoring of crops using novel microneedle ele... more This paper presents an impedimetric biosensor for monitoring of crops using novel microneedle electrodes for minimally invasive, sensitive measurements, compatible with smart agriculture developments. The biosensor was fabricated through polydimethylsiloxane imprinting using a high-resolution 3D printed negative mold. This method allows for fabrication of tailored microneedles with heights up to 500 µm, required to penetrate through the epidermis of a leaf. The sensor was tested by recording the bioimpedance of Barely leaves and comparing its performance to conventional planar and needle electrodes. Furthermore, we present evidence of a diurnal pattern in plant bioimpedance that was detected by monitoring the leaf bioimpedance under controlled conditions.

2020 42nd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC)

Directing the fate of human mesenchymal stem/stromal cells (hMSCs) toward bone formation using me... more Directing the fate of human mesenchymal stem/stromal cells (hMSCs) toward bone formation using mechanical strain is a promising approach in regenerative medicine related to bone diseases. Numerous studies have evaluated the effects of vibration or cyclic tensile strain on MSCs towards developing a mechanically-based method for stimulating differentiation. Here, we study the differentiation of hMSCs cultured on elastic polydimethylsiloxane (PDMS) membrane, which is magnetically actuated to induce periodically varying strain. The strain distribution across the membrane was calculated by finite-element modeling and demonstrates three main areas of different strain amplitudes. The strain effect on the hMSCs was evaluated by measuring the mineralization of differentiated hMSCs using Alizarin S red stain. The results indicate a straindependent differentiation of hMSCs, where the highest region of strain on the membrane resulted in the most accelerated differentiation. Osteogenic differentiation was achieved as early as two weeks, which is significantly sooner than control hMSCs treated with osteogenic media alone.

2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII)

A miniaturized drug delivery system suitable for in-vivo biomedical applications is presented. Th... more A miniaturized drug delivery system suitable for in-vivo biomedical applications is presented. The system consists of an electrolytic pump driving a micro bellows membrane as an actuator for delivery through microneedles. A two-photon polymerization 3D printing technique was used to fabricate a reservoir equipped with microneedles. Analytical characterization of the flow rate through the microneedles showed an outgoing flow rate ranging from 63 µL/min to 520 µL/min for an applied pressure of 0.1 to 1 kPa. The assembled system with an overall size of 3.9 mm × 2.1 mm × 2 mm achieved delivery of 4 ± 0.5 µL within 12 seconds of actuation. A penetration test of the microneedle into a skin-like material confirms its potential for transdermal delivery.

Advanced Science, 2021

Precision farming has the potential to increase global food production capacity whilst minimizing... more Precision farming has the potential to increase global food production capacity whilst minimizing traditional inputs. However, the adoption and impact of precision farming are contingent on the availability of sensors that can discern the state of crops, while not interfering with their growth. Electrical impedance spectroscopy offers an avenue for nondestructive monitoring of crops. To that end, it is reported on the deployment of impedimetric sensors utilizing microneedles (MNs) that can be used to pierce the waxy exterior of plants to obtain sensitive impedance spectra in open‐air settings with an average relative noise value of 3.83%. The sensors are fabricated using a novel micromolding and release method that is compatible with UV photocurable and thermosetting polymers. Assessments of the quality of the MNs under scanning electron microscopy show that the replication process is high in fidelity to the original design of the master mold and that it can be used for upward of 20...

Advanced Materials Technologies

2020 42nd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), 2020

In-vitro transfection of cells by electroporation is a widely used approach in cell biology and m... more In-vitro transfection of cells by electroporation is a widely used approach in cell biology and medicine. The transfection method is highly dependent on the cell culture’s electrical resistance, which is strongly determined by differences in the membranes, but also on the morphology of the electrodes. Microneedle (MN)-based electrodes have been used to concentrate the electrical field during electroporation, and therefore maximize its effect on cell membrane permeability. So far, the methods used for the fabrication of MN electrodes have been relatively limited with respect to the needle design. In this work, we provide a method to fabricate MNs using 3D printing, which is a technology that provides a high degree of flexibility with respect to geometry and dimensions. Pyramidal-shaped MN designs were fabricated and tested on HCT116 cancer cells. Customization of the tips of the pyramids permits tailoring of the electrical field in the vicinity of the cell membranes. The fabricated d...

2019 IEEE 14th International Conference on Nano/Micro Engineered and Molecular Systems (NEMS), Apr 1, 2019

Advanced materials and technologies, 2021

Advanced Engineering Materials

Microneedles (MNs) are playing an increasingly important role in biomedical applications, where m... more Microneedles (MNs) are playing an increasingly important role in biomedical applications, where minimally invasive methods are being developed that require imperceptible tissue penetration and drug delivery. To improve the integration of MNs in microelectromechanical devices, a high-resolution 3D printing technique is implemented. A reservoir with an array of hollow MNs is produced. The flow rate through the MNs is simulated and measured experimentally. The mechanical properties of the 3D printed material, such as elasticity modulus and yield strength, are investigated as functions of printing parameters, reaching maximum values of 1750.7 and 101.8 MPa, respectively. Analytical estimation of the MN buckling, fracture, and skin penetration forces is presented. Penetration tests of MNs into a skin-like material are conducted, where the piercing force ranges from 0.095 to 0.115 N, confirming sufficient stability of MNs. Furthermore, 200 and 400 μm-long MN arrays are used to successfully pierce and deliver into mouse skin with an average penetration depth of 100 and 180 μm, respectively. A biocompatibility assessment is performed, showing a high viability of HCT 116 cells cultured on top of the MN's material, making the developed MNs a very attractive solution for many biomedical applications.

Journal of Microelectromechanical Systems

Bellows membranes are essential elements in many actuator devices. Currently, the size, shape, an... more Bellows membranes are essential elements in many actuator devices. Currently, the size, shape, and dimensions of bellows membranes are limited by the fabrication process constraints. Miniaturizing the bellows membranes is a prerequisite for the development of integrated systems with novel capabilities as needed, for example, in advanced biomedical devices. Using a two-photon polymerization, 3-D printing technique, we present a high-resolution, high-yield, and customizable manufacturing process to produce Parylene C micro-bellows. An optimization of the crucial design parameters is performed using finite element modeling from which designs with high deflection and low stress were obtained. Different micro-bellows designs are fabricated and characterized. The total volume of the fabricated models ranges from 3 to 0.3 mm 3 and the minimum feature size is 60 µm. The achieved cumulative deflection ranges from 300 to 570 µm.