Development of a novel cell traction force transducer based on cholesteryl ester liquid crystals. Characterisation, quantification and evaluation of a cholesteryl ester liquid crystal based single cell force transducer system.

In biomechano-transducing, cellular generated tension can be measured by soft substrates based on polymers but these techniques are limited either by spatial resolution or ability to detect localised cell traction forces (CTF) due to their non-linear viscous behaviour under shear rates. A newly developed cell traction force transducer system based on cholesteryl ester lyotropic liquid crystals (LCTFT) was developed to sense localised traction forces of human keratinocyte cell lines (HaCaTs), in which the length of the deformation line induced represents the intensity of the CTF exerted. The physical properties of the cholesteryl ester based lyotropic liquid crystals (LLC) were characterised by using polarising microscopy, rheology, atomic force microscopy (AFM) based nano-indentation, spherical indentation, and micro-tensile tests. The interactions of LLC with cells were studied by using cell viability studies, cytochemical treatments, widefield surface plasmon resonance (WSPR) microscopy and various immuno-staining techniques. The results show that LLC is thermally stable (0 - 50 oC) and linearly viscoelastic below 10 % shear strain at shear rates of < 1 s-1. AFM nano and spherical indentations show a good agreement on the Young¿s modulus of both determined at ~110 kPa which is close to the elastic modulus of the epidermis. The Poisson¿s ratio of LLC was determined at ~0.58 by using micro tensile tests. The biophysical interaction studies indicated that LLC is biocompatible and allowed cell attachment. Cell relaxation technique by cytochalasin-B treatment suggested that the attachment and contraction of cells on LLC was due to the contractile activity of actin cytoskeletons that are mediated by focal adhesions. The staining experiments showed that cells consistently expressed the same suites of integrins (¿2, ¿3, ¿5 and ¿1) and ECM proteins (collagen type IV, laminin and fibronectin) on both glass and LLC coated substrates. Interfacial interaction of cells with LLC observed via the staining of actin and vinculin, and WSPR imaging suggest the association of marginal actin filaments and focal adhesions in attaching HaCaT cells to the LLC. Linear static analysis applied in the Finite Element model of focal adhesion-LC confirmed the compressive force patterns induced by cells. By applying cell relaxation techniques and Hooke¿s theorem, the force-deformation relationships of the LLC were derived and used for direct quantification of CTF in culture. The sensitivity of the LCTFT was implied by a wide range of CTF (10 - 140 nN) measured at high resolutions (~2 ¿m). Nonetheless, a custom-built cell traction force measurement and mapping software (CTFM) was developed to map CTF of single cells. Reliability of the LCTFT was evaluated by using a known pharmacological active cytokine, TGF-¿1, in inducing contraction of human keratinocytes. This study inferred internal consistency and repeatability of the LCTFT in sensing contraction responses of HaCaT cells in a concentration dependent manner of TGF-¿1. The overall LCTFT and CTFM software had shown good potential for use in the study of contraction and migration of keratinocytes.Malaysia Ministry of Higher Educatio

A Bluetooth And Vision Controlled Automatic Guided Vehicle

The aim of this project is to construct a Bluetooth (2.4GHz) and vision controlled auto guided vehicle (AGV) for use during the COVID-19 pandemic. The auto guided vehicle can be maneuvered by using an application in mobile phone or auto guided function. The auto guided function of the vehicle is following the label that is affixed on the user. Bluetooth communication was applied to control the AGV at a maximum distance of 10&nbsp;m. The auto guided vehicle can carry a maximum of 10&nbsp;kg load. The vision system applied could track and follow the human movement affixed with a label. The best following distance of the AGV developed is within 80cm and the angle of detection is 55°. The auto guided vehicle can reduce the risk of the user in contacting the AGV and hence, minimising the risk of virus infection. It also helps the senior user to save energy in pushing the heavy cart

Biocomposite conductive scaffold based on PEDOT:PSS/nHA/ chitosan/PCL: fabrication and characterization

Biomaterial-based scaffolds with suitable characteristics are highly desired in tissue engineering (TE) application. Biocomposites based on polymer and ceramics increase the chance for modulating the properties of scaffold. In recent years, researchers have considered conductive polymers to be used in TE application, due to their conductivity. This property has a good impact on tissue regeneration. A suitable design for bone substitute that consists of considerations such as material component, fabrication technique and mechanical properties. The previous studies on PEDOT:PSS/nHA/CS showed high wettability rate but low mechanical properties. Polycaprolactone (PCL) is a biodegradable and biocompatible polymer with a low wettability. The incorporation of PCL inside biocomposite can lead to the decrement in wettability and increment in mechanical property. In addition, this paper would examine the feasibility of blending of PCL and chitosan to fabricate PEDOT:PSS/nHA/CS composite scaffold. The fabrication technique of freezing/ lyophilization was used in this study. The scaffolds were characterized morphologically using scanning electron microscopy (SEM). Wettability was studied using a contact angle instrument. The attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) spectra interpreted the presence of polymeric ingredients within composite scaffold. Conductivity of the scaffolds was measured using a Digital Multimeter. In-vitro biological evaluation of the scaffolds was studied using human skin Fibroblast (HSF) cell line. The morphological study of biocomposite PEDOT:PSS/nHA/CS/PCL scaffold revealed random pore sizes and 66% porosity. Contact angle of the scaffold was increased and the swelling property and pore sizes were decreased after blending of PCL polymer. The viability of HSF cells on biocomposite PEDOT:PSS/nHA/CS/PCL scaffold was 85%. After 7 days, SEM analysis revealed the presence of cells on the surface of scaffold. In conclusion, the results suggested that PEDOT:PSS/nHA/CS/PCL biocomposite scaffold was non-toxic to cells and has suitable properties

Fabrication of A Diode-based Salt Solution Sensor

High blood pressure/hypertension is a severe medical issue among Malaysians that could be reduced by monitoring our salt/sodium intake. One way is to use intraoral salt sensor; this in-mouth method however may cause discomfort and adopts complex and costly fabrication processes. Hence, an external and reusable electronic device, that could be used as a “sweat-sensorâ€, is preferred in detecting the sodium intake of the body. In this study, a potentiometric diode-based salt solution sensor was designed and fabricated in order to detect different salt solution concentrations with applied external voltage. A p-n junction diode sensor was successfully designed and fabricated using four consecutive techniques; thermal wet oxidation, photolithography, thermal diffusion and metallization. The average sheet resistance and resistivity of the diode sensor were measured to be 3.50 x 105 ± 0.66 Ωâ„sq and 3.05 ± 0.5 Ωcm respectively. This sensor showed ideal I-V diode characteristics with a knee voltage of 11.5V in forward bias condition and breakdown voltage of -4 V in reverse bias condition. For salt concentration detection, the sensor was able to detect salt concentration changes with respect to current flow, up to 45 mg/mL

Tracking Traction Force Changes of Single Cells on the Liquid Crystal Surface

YesCell migration is a key contributor to wound repair. This study presents findings indicating that the liquid crystal based cell traction force transducer (LCTFT) system can be used in conjunction with a bespoke cell traction force mapping (CTFM) software to monitor cell/surface traction forces from quiescent state in real time. In this study, time-lapse photo microscopy allowed cell induced deformations in liquid crystal coated substrates to be monitored and analyzed. The results indicated that the system could be used to monitor the generation of cell/surface forces in an initially quiescent cell, as it migrated over the culture substrate, via multiple points of contact between the cell and the surface. Future application of this system is the real-time assaying of the pharmacological effects of cytokines on the mechanics of cell migration

Oncoming Vehicle Detection with Variable-Focus Liquid Lens

Computer vision plays an important role in autonomous vehicle, robotics and manufacturing fields. Depth perception in computer vision requires stereo vision, or fuse together a single camera with other depth sensors such as radar and Lidar. Depth from focus using adjustable lens has not been applied in autonomous vehicle. The goal of this paper is to investigate the application of depth from focus for oncoming vehicle detection. Liquid lens is used to adjust optical power while acquiring images with the camera. The distance of the oncoming vehicle can be estimated by measuring the oncoming vehicle’s sharpness in the images with known lens settings. The results show the system detecting oncoming vehicle at ±2 meter and ±4 meter using depth from focus technique. Estimation of oncoming vehicles above 4 meter can be done by analysing the relative size of the vehicle detected

The Development of an Enhanced Smart Saltwater Desalination System

Water is an essential resource for life. We also know that water scarcity is a huge problem that happens around the world and especially in countries that have low economies and large populations. This thesis proposes desalination system based on solar panels for enhancing the desalination process. This project aims to produce clean water from the salt water using the concept of evaporation and the result that comes from this project is to produce a desalination system that can treat salt water to clean water not just during the day but also at night. In this project, the desalination system works by solar heating which sunlight will heat the salt water in the basin to produced evaporated water and the bulb will replace sunlight during night since its capability works same as sunlight

Development of a twin-head infusion pump for micromixing

Mixing is a crucial process in most of the industrial technology such as the operation of chemicals and fermentation reactors, combustion engines, polymer blends, and pharmaceutical formulations [1]. For handling a smaller volume of liquid, micromixing is a suitable method that can be applied. Micromixing (micromixer) is one of the microfluidic functions for mixing and blending liquids as precursors for biological process such as cell activation, enzyme reaction, and drug delivery system [2, 3]. There are several advantages of applying microfluidic device (micromixer) in the chemical technological processes such as processing accuracy, efficiency, minimum usage of reagents and ease of disposing of devices and fluids [3]. Basically, micromixers are categorised into passive and active micromixers. Passive micromixer consists of no moving parts and free from additional friction. It does not use external forces, fully dependent on molecular diffusion and chaotic advection for mixing process [4]. In contrast to active micromixers, external forces are applicable to active micromixers by implementing moving elements either within the microchannels, a time-variant, or a pressure field [5]. To create the pressure field differences for moving the liquid within the micromixer, an infusion pump is usually applied

Fabrication of gelatin scaffolds using thermally induced phase separation technique

Gelatin is considered as a partially degraded product of collagen and it is a biodegradable polymer which can be used to produce scaffolds for tissue engineering. Three-dimensional, porous gelatin scaffolds were fabricated by thermally induced phase separation and freeze-drying method. Their porous structure and pore size were characterized by scanning electron microscopy. Scaffolds with different pore sizes were obtained by adjusting the concentration of the gelatin solution. Scaffolds with 3.75% (w/v) gelatin and 5% (w/v) gelatin produced pores ranging from 100 to 450µm. The average pore size increased with an increase in gelatin concentration. The properties of the scaffolds in terms of water uptake were studied. The results showed that when the concentration of the gelatin solution was changed from 3.75% to 5%, the water absorption of the fabricated scaffolds decreased by 104%. The increment in the concentration of gelatin induced a reduction in water uptake in the scaffolds produced. © 2018 Materials and Energy Research Center

Construction of Hexagonal Structures Using a 3D Bioprinter Based on Customized G-Code:

Three-dimensional (3D) bioprinting is adopted from the existing technology of 3D printing that is able to recreate the microenvironment of tissue structures or organs. However, the existing printing mechanism is normally based on slices of a 3D structure in computer-aided slicer software and prints in horizontal and diagonal manners. Such printing mechanism involving soft bioink which does not polymerise in short period of time produces distorted constructs due to the thixotropic properties of the bioink. To circumvent this problem, G-codes for simple 3D bioprinting mechanism were derived. A 3D bioprinter has been developed to implement unidirectional printing for different concentration of bioink. The modified coding was successfully customized for printing single layer to multilayer hexagonal structures. Additionally, the dimension accuracy of the 3D printing in producing similar dimensions of a design in CAD software is highly dependent on the concentration of the bioink applied. The results show that up to 97 % of printing accuracy can be achieved by applying 10: 50 % v/v of alginate/gelatin bioink