Assessment of microbial contamination in laser materials processing laboratories used for prototyping of biomedical devices.

Microbial contamination of medical devices during pilot production can be a significant barrier as the laboratory environment is a source of contamination. There is limited information on microbial contaminants in laser laboratories and environments involved in the pilot production of medical devices. This study aimed to determine the bioburden and microbial contaminants present in three laser laboratories - an ISO class 7 clean room, a pilot line facility and a standard laser laboratory.

Femtosecond Laser-Induced Crystallization of Amorphous Silicon Thin Films under a Thin Molybdenum Layer.

A new process to crystallize amorphous silicon without melting and the generation of excessive heating of nearby components is presented. We propose the addition of a molybdenum layer to improve the quality of the laser-induced crystallization over that achieved by direct irradiation of silicon alone. The advantages are that it allows the control of crystallite size by varying the applied fluence of a near-infrared femtosecond laser.

Femtosecond Laser Assisted Crystallization of Gold Thin Films.

We propose a novel low temperature annealing method for selective crystallization of gold thin films. Our method is based on a non-melt process using highly overlapped ultrashort laser pulses at a fluence below the damage threshold. Three different wavelengths of a femtosecond laser with the fundamental (1030 nm), second (515 nm) and third (343 nm) harmonic are used to crystallize 18-nm and 39-nm thick room temperature deposited gold thin films on a quartz substrate.

Laser-Induced Periodic Surface Structure Enhances Neuroelectrode Charge Transfer Capabilities and Modulates Astrocyte Function.

The brain machine interface (BMI) describes a group of technologies capable of communicating with excitable nervous tissue within the central nervous system (CNS). BMIs have seen major advances in recent years, but these advances have been impeded because of a temporal deterioration in the signal to noise ratio of recording electrodes following insertion into the CNS. This deterioration has been attributed to an intrinsic host tissue response, namely, reactive gliosis, which involves a complex series of immune mediators, resulting in implant encapsulation via the synthesis of pro-inflammatory signaling molecules and the recruitment of glial cells.

Monitoring of pH and temperature of neuropathic diabetic and nondiabetic foot ulcers for 12 weeks: An observational study.

Wound bed assessment is largely reliant on subjective interpretation without recourse to objective tools or biomarkers. The identification of a point of care, reliable biomarker would enhance assessment and ultimately clinical decision making. Two potentially emerging wound biomarkers exist: surface pH and surface temperature.

Enhanced thermal imaging of wound tissue for better clinical decision making.

Unlabelled: Infrared cameras are increasingly applied in clinical applications as they allow fast, inexpensive and non-contact temperature measurements. As abnormal heat distribution can indicate illness, infrared cameras have been applied in the prediction, diagnosis and monitoring of medical conditions. Current practices, however, often overlook the importance of emissivity when taking thermal measurements.

Laser microfabrication of a microheater chip for cell culture outside a cell incubator.

Microfluidic chips have demonstrated their significant application potentials in microbiological processing and chemical reactions, with the goal of developing monolithic and compact chip-sized multifunctional systems. Heat generation and thermal control are critical in some of the biochemical processes. The paper presents a laser direct-write technique for rapid prototyping and manufacturing of microheater chips and its applicability for lab-on-a-chip cell culture outside a cell incubator.

In one harness: the interplay of cellular responses and subsequent cell fate after quantum dot uptake.

Rapid growth and expansion of engineered nanomaterials will occur when the technology can be used safely. Quantum dots have excellent prospects in clinical applications, but the issue of toxicity has not yet been resolved. To enable their medical implementation, the effect on, and mechanisms in, live cells should be clearly known and predicted.

Comparison of ablation mechanisms at low fluence for ultrashort and short-pulse laser exposure of very thin molybdenum films on glass.

Complete removal of a loosely adhered very thin molybdenum film from a glass substrate is investigated for both femtosecond and nanosecond lasers at different wavelengths. Atomic force microscopy and scanning electron microscopy confirm that ablation of the molybdenum film by femtosecond pulses occurs close to the damage threshold fluence, creating minimal damage to the substrate. This is in contrast to nanosecond laser processing where significant substrate damage at the equivalent damage threshold fluence is observed.

Sensing of p53 and EGFR Biomarkers Using High Efficiency SERS Substrates.

In this paper we describe a method for the determination of protein concentration using Surface Enhanced Raman Resonance Scattering (SERRS) immunoassays. We use two different Raman active linkers, 4-aminothiophenol and 6-mercaptopurine, to bind to a high sensitivity SERS substrate and investigate the influence of varying concentrations of p53 and EGFR on the Raman spectra. Perturbations in the spectra are due to the influence of protein-antibody binding on Raman linker molecules and are attributed to small changes in localised mechanical stress, which are enhanced by SERRS.

Single-pulse laser ablation threshold of borosilicate, fused silica, sapphire, and soda-lime glass for pulse widths of 500 fs, 10 ps, 20 ns.

In this work, we report a comparative study of the laser ablation threshold of borosilicate, fused silica, sapphire, and soda-lime glass as a function of the pulse width and for IR laser wavelengths. We determine the ablation threshold for three different pulse durations: τ=500  fs, 10 ps, and 20 ns. Experiments have been performed using a single laser pulse per shot in an ambient (air) environment.

Mechanically inspired laser scribing of thin flexible glass.

Laser cutting of thin glass (<100  μm) has proven problematic. We describe an alternative laser scribing method that utilizes surface stress raisers. An ultrashort laser source is used to precisely pattern a plurality of aligned elliptical recesses on the glass.

Laser direct-write technique for fabricating microlens arrays on soda-lime glass with a Nd:YVO4 laser.

A one-step direct-write technique for fabricating spherical microlenses on soda-lime glass substrates is described. Using a Q switched Nd:YVO(4) laser combined with a galvanometer system, square and triangular microlens arrays were fabricated. The focal length of microlenses is measured using direct and nondirect methods.