Antibiotic resistance is a growing concern in the treatment of infectious disease worldwide. Point-of-care (PoC) assays which rapidly identify antibiotic resistance in a sample will allow for immediate targeted therapy which improves patient outcomes and helps maintain the effectiveness of current antibiotic stockpiles. Electrochemical assays offer many benefits, but translation from a benchtop measurement system to low-cost portable electrodes can be challenging. Using electrochemical and physical techniques, this study examines how different electrode surfaces and bio-recognition elements, i.e. the self-assembled monolayer (SAM), affect the performance of a biosensor measuring the hybridisation of a probe for antibiotic resistance to a target gene sequence in solution. We evaluate several commercially available electrodes which could be suitable for PoC testing with different SAM layers and show that electrode selection also plays an important role in overall biosensor performance.

Associate Editor Smadar Cohen oversaw the review of this article.

Cranioplasty implants are routinely fabricated from commercially pure titanium plates by maxillofacial prosthetists. The differing fabrication protocols adopted by prosthetists working at different hospital sites gives rise to considerable variations in surface topography and composition of cranioplasty implants, with residues from the fabrication processes having been found to become incorporated into the surface of the implant. There is a growing recognition among maxillofacial prosthetists of the need to standardise these protocols to ensure quality and consistency of practice within the profession. In an effort to identify and eliminate the source of the inclusions associated with one such fabrication protocol, the present study examined the surfaces of samples subjected to each of the manufacturing steps involved. Surface and elemental analysis techniques identified the main constituent of the surface inclusions to be silicon from the glass beads used to texture the surface of the implant during fabrication. Subsequent analysis of samples prepared according to a revised protocol resulted in a more homogeneous titanium dioxide surface as evidenced by the reduction in area occupied by surface inclusions (from 8.51% ± 2.60% to 0.93% ± 0.62%). These findings may inform the development of improved protocols for the fabrication of titanium cranioplasty plates.

The development of 3D-printed sensors and actuators from piezocomposite materials has increased in recent years due to the ease of production, low-cost and improved functionality additive manufacturing provides. The piezocomposite material developed in this work has the potential to be used as a functional material in stereolithographic additive manufacturing by combining the optical, viscoelastic properties of NOA 65 and the piezoelectric properties of Barium Titanate. The new (0–3) piezocomposite material consists of Norland Optical Adhesive 65 (NOA 65) as the polymer matrix and Barium Titanate (BaTiO3) with particles sizes (100 nm, 200 nm and 500 nm) as the dielectric filler. We synthesized thin film samples of the (0–3) piezocomposite with 60% w/w BaTiO3 using solution mixing and spin coating method to produce samples with layer thickness of 100 µm. Fourier-transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) techniques were used to analyze the microstructure of the piezocomposite to determine the effect of different particles sizes of BaTiO3 on the structural and mechanical properties of the composite. The longitudinal piezoelectric coefficient d33 was also measured using the laser vibrometer technique. Both single point scans and full surface scans were carried out to obtain the average piezoelectric coefficient d33 of the composite material. The results of the SEM confirmed the (0–3) structure of the piezocomposite material with isolated BaTiO3 nanoparticles. It further showed the uniform distribution of the BaTiO3 nanoparticles across each of the samples. FTIR analysis showed that the filler nanoparticles had no effect on the native structure of the polymer matrix. The longitudinal piezoelectric coefficient d33 of the piezocomposite material was observed to increase with increasing BaTiO3 particle sizes, while the indentation modulus of the composite investigated using the method of Oliver and Pharr was observed to decrease with an increase in particle size. Results from the single point scans showed the composite with BaTiO3 particle size 100 nm, 200 nm and 500 nm having an average d33 of 2.1 pm/V, 3.0 pm/V and 3.9 pm/V while the average d33 obtained from the full surface scan of 1430 scan points showed 1.4 pm/V, 6.1 pm/V, 7.2 pm/V.

In this study, we have developed and characterized two different (0-3) piezoelectric composite materials with potential to be used in sensing applications. The composite materials were made using Polydimethylsiloxane (PDMS) as the polymer matrix with Barium Titanate (BaTiO3), and Lead Zirconate Titanate (PZT51) as the dielectric fillers. Thin film samples of the (0-3) piezocomposites were prepared using a solution mixing and spin coating method to produce composites with (0-3) connectivity pattern and layer thickness of 100 µm. The microstructure of the piezocomposites were analyzed using a scanning electron microscope to determine the connectivity structure and homogeneity of the piezocomposites. The mechanical properties of the composites were determined using the method of Oliver and Pharr. FTIR analysis was used to determine the effects of the fillers on the structure of the piezocomposite. The average piezoelectric d33 coefficient of the piezocomposites were also measured using the laser vibrometer technique and determined to be 30 pm/V for the piezocomposite consisting of Barium Titanate (BaTiO3) and 32 pm/V for the piezocomposite consisting of Lead Zirconate Titanate (PZT51).