In this work, poly (L-lactic acid) (PLLA) tubular scaffold was prepared by adding tetrabutylammonium bromide (TBAB) to the PLLA spinning solution. The effects of the introduction of TBAB on the morphology, crystallisation and mechanical properties of PLLA scaffolds were systematically studied by means of scanning electron microscope, differential scanning calorimetry (DSC), X-ray diffraction (XRD) and attenuated total reflectance Fourier-transform infrared spectroscopy. The results show that the introduction of TBAB improves crystallinity and mechanical property of the PLLA scaffold. As the TBAB content in the spinning solution increases, the mechanical properties of the PLLA tubular scaffold increase first and then decrease. The circumferential tensile strength of the PLLA tubular scaffold prepared by the spinning solution with addition of TBAB were found to increase by up to 323%. The results of DSC and XRD show that the introduction of TBAB can improve the crystallinity of the PLLA fibres. The Fourier-transform infrared spectroscopy test results demonstrate that the chain orientation of the PLLA fibres increases with the TBAB content in the spinning solution and induces the formation of α/α′ crystal phase structure in the PLLA fibres, which is the main reason for the substantial improvement of the mechanical properties of the tubular scaffold.

Three-dimensional bicontinuous nanoporous copper (NPC) with a pore size of 10–60 nm was fabricated by dealloying titanium–copper–cobalt amorphous ribbons in 0.23 M hydrofluoric acid (HF) solution for 1–12 h. It is found that dealloyed ribbons show sandwich-like layered structure in the cross-section and the pore size in the outer layer is larger than that in the core layer. The NPC ribbons, polarised in 1 M potassium hydroxide (KOH) solution for 30 min, delivered an excellent electrochemical performance with a specific capacitance of 202.3 mF/cm² at the current density of 5 mA/cm² in 1 M KOH electrolyte and good cycling stability of 90% capacitance retention after 5000 cycles at 20 mA/cm².

An efficient synthesis process approach based on a chemical solution route is developed for the cadmium selenide quantum dots (CdSe QDs) that utilise photonic and optoelectronic device manufacturing. The developed route consists of dissolving the cadmium chloride (CdCl₂.H₂O), 2-mercaptoethanol and sodium selenide anhydrous (Na₂SeO₃). The different characterisation parameters such as ultraviolet (UV) absorbance, x-ray diffraction (XRD), scanning electron microscopy, energy dispersive x-ray and transmission electron microscopy (TEM) were employed in order to develop the CdSe QDs. When the sample was analysed from the UV–visible studies, the bandgap was about 2.16 eV, whereas the bulk CdSe bandgap was about 1.78 eV. The developed CdSe QDs possessed a cubic crystal structure with crystalline dimensions of about 4.86 nm. Its surface morphology and structure showed the smooth appearance of the surface. The result indicated agglomerated spheres. Ultimately, according to XRD and TEM results, the crystalline dimension was determined in good agreements.

In this work, a novel glutathione and pH serial dual-responsive drug delivery system has been developed, which was constructed with chitosan (CS), carbon dots (CDs) and hyaluronic acid (HA) modified the mesoporous silica nanoparticles (MSNs). The system showed excellent drug loading efficiency, controlled release and targeted delivery. In addition, the platform (MSN-CS@HA-CDs) exhibited fluorescence imaging property. The prepared drug delivery system appeared to be a promising cancer treatment platform.

Model-based analysis of a dielectrophoretic microfluidic device for realising 3D-focusing is presented in this work. The electrode configuration is made up of several finite-sized planar electrodes positioned on either side of the microchannel's top and bottom surfaces; the electrodes on the top surface and bottom surface of the same side form a pair. The forces associated with inertia, buoyancy, gravity, and dielectrophoresis are included in the model. As per the model, it is possible to use the proposed device to achieve 3D-focusing at the desired location along the width of the microchannel. Also, the proposed device can achieve 3D-focusing irrespective of the type of micro-scale entity. Two parameters for quantifying the efficacy of the microfluidic device in achieving 3D-focusing are presented – horizontal and vertical focusing parameters. The model demonstrates that the radius of micro-scale entity, electrode/gap lengths, electrode width, microchannel height, number of electrodes, applied electric potentials, and volumetric flow rate influence horizontal and vertical focusing parameters. The mathematical model is thus useful in designing dielectrophoresis-based 3D-focusing with desired performance metrics for on-chip flow cytometry.

Polymer microelectromechanical system (MEMS) devices emerge as the new class of sensor devices for bio-sensing applications exhibiting high mechanical deformability and sensitivity. In this work, the design and fabrication of electrostatically actuated polydimethylsiloxane (PDMS) MEMS cantilever on flexible PDMS substrate is presented. The physical parameters of the cantilever were analysed and optimised using Taguchi method coupled with COMSOL Multiphysics software. This work focusses on the development of a novel approach for the simple and cost-effective fabrication process of PDMS cantilevers and subsequently its arrays. The proposed device consists of a PDMS body with the metal bottom electrode, PDMS anchor, and PDMS cantilever beam as its top electrode and immobilization surface. The work presented is of the cracking phenomenon in the metal layer sputtered on the PDMS substrate. The novelty of the fabrication process is the use of low-cost processes, no need for sophisticated lithography tools or etching equipment. Also, the process allows the use of alternate material as base substrate (glass, silicon wafer etc.) wherein it is not consumed and is reusable. The fabricated device is then electrically characterised for its pull-in characteristics.

The optimal design of repeaters for current-mode (CM) nano-interconnects is conducted and compared with that for voltage-mode (VM) ones. Both Cu and carbon nanotube (CNT) nano-interconnects are considered and studied, with the contact resistance treated appropriately. In comparison with the VM ones, the CM nano-interconnects can not only demonstrate better electrical performance, but also require fewer repeaters, thereby saving more valuable chip area. In the delay-optimal repeater design of multi-walled CNT interconnects, for instance, the optimal number of repeaters can be reduced by 120% with the implementation of CM signalling scheme.

Titanate nanomaterial thin films were prepared using an alkaline hydrothermal method in various molar ratios of NaOH/KOH mixed aqueous solution at a total concentration of 10 M. The as-prepared nanomaterials were characterised by X-ray diffractometer, scanning electron microscopy and transmission electron microscopy. The effects of the molar ratio of Na⁺/K⁺ on the morphologies and microstructures of titanate nanomaterials were studied. With the molar ratio of Na⁺/K⁺ decreases, the mean diameter of nanomaterials increases. The phase and structure transformation of nanomaterials were from sodium titanate nanotubes to potassium titanate nanowires and the formation mechanism was discussed.

Carbon quantum dots (CQDs) decorated Bi₂WO6 nanocomposites were successfully synthesised by a facile hydrothermal method. The prepared samples were characterised by the XRD, FESEM, TEM, XPS, UV–vis DRS, photocurrent and photoluminescence (PL) techniques. The DRS, photocurrent, PL spectra measurements reveal that the introduction of CQDs could broaden the absorption edge and accelerate the separation and transportation efficiency of carriers. Moreover, a reasonable charge transfer approach was given out based on the calculated work function and the differential charge difference. The CQDs/Bi₂WO₆-2 sample provides the optimal activity for photodegradation of CIP under simulated sunlight irradiation. It is hopeful that this work not only gives a reference for the design of CQDs/Bi₂WO₆ composites, but also provides some mechanistic insights into enhanced photoactivity.

Phase transformation of hydrogenated nanocrystalline silicon (nc-Si:H) films was essential in the solar cells industry. Therefore, the plasma chemistry monitoring of in-situ diagnostics optical emission spectroscopy (OES) of plasma-enhanced chemical vapour deposition (PECVD) is deemed crucial for investigating the phase transformation. The proposed PC2-OES algorithm can be used to monitor the PECVD process health condition of the crystallisation rate at different hydrogen dilution ratios. Principal component analysis (PCA) was performed to distinguish the crucial role of nc-Si:H emission characteristics of plasma chemistry and the resultant crystallisation rate. Measurement results revealed that OES spectra characterisation confirmed that the crystallisation rate index (Hα*/SiH*) was highly correlated to hydrogen dilution ratio (R) and phase transformation of nc-Si:H film. The proposed PCA-based evaluation method will provide valuable information to reflect consistently the crystallisation rate of deposited films with different hydrogen dilution ratio and possibly other processing parameters of mass flow rate and applied power density.

Here the theoretical and experimental investigation for enhancing surface plasmon resonance (SPR) sensitivity in a side-coupled excitation system by the application of polymethylmethacrylate (PMMA) polymer thin films is presented. Proper selection of film materials, gold layer thicknesses d _Au and SPR incident angle (θ _SPR) resulted in the increased effective refractive index of the sensing region, and hence of the device sensitivity, and the dynamic detection range. This work demonstrates, by first-order approximations, a characterisation scheme of SPR chips with unknown gold layer thickness d _Au and uncertainty in SPR incident angle. The scheme utilised fitting theoretical calculations to measured SPR responses while varying d _Au and θ _SPR in equations. Device sensitivity nearly doubled following application of thin PMMA thin films on gold surfaces when sensing water-chloroform mixtures as opposed to untreated surfaces that lacked a PMMA layer. The proposed work demonstrates a facilitative balance between theoretical expectations and experimental data to develop sensors for future applications.

In a conventional glass microfluidic system, the vertical connection is the most frequently used for connections between a microfluidic device and its peripheral equipment. However, it leads to a significant pressure drop at the inlet of a microfluidic device, decreases the flow velocity, and can introduce few samples than expected. To overcome these problems, a horizontal connection method for glass microfluidic devices, which have advantages such as keeping pressure/flow velocity, compatible with small space, reduced sample loss and convenience for modularisation is reported. These advantages are important for high-speed analysis on precious samples such as single-cell flow cytometry. In this work, they proposed a horizontal connection method which showed compatibility with high pressure (at least 0.6 MPa) at inlet without leakage, small loss of injected samples (<0.11%), and 22% faster flow velocity along the direction of applied pressure than that of vertical connection.

In this work, it is shown that the spring constant model for rectangular fixed–fixed beam used in the literature for high-speed applications is not correct and the model is improved for all fixed–fixed beams with a desired symmetrical shape. The new model is used to calculate the resonance frequency of the fabricated high-speed-specific 3D bridge named boat-like shape beam existing in the literature. The comparison shows that the model result is in good agreement with the simulation and measurement results. Also, the concept of the miniature microelectromechanical systems switched capacitors will be explained and it is shown that the rectangular beam with a simple fabrication process can be designed to achieve high speed about 150 ns like a boat-like shape beam which needs to two specific lithography processes that are so involved.

In this study, the electrospinning of polycaprolactone (PCL) nanofibres with different solvents and various ratios as well as electrospinning on the poly lactic acid plate are investigated for use on the wounds. Utilising several materials at various concentrations, including dimethylformamide–methylene chloride solvent and methylene chloride and methanol solvent, electrospinning of PCL nanofibres are performed. The results show that the obtained fibres have a large number of beaded fibres when using the dimethylformamide–methylene solvent. However, the beaded fibres reduced for methylene chloride and methanol solvent. After adding the glass ionomer label 1 and ciprofloxacin, the beaded fibres intensively decline and also Young's modulus reaches a maximum value (5.2 MPa). Therefore, the combination of glass ionomer label 1 and ciprofloxacin with the methylene chloride and methanol solvent can provide very interesting results to reduce the number of beaded fibres, which show the combination is very suitable for use in wounds.