Etching characteristics and properties of {1 1 0} silicon crystal planes used as 45° optical mirrors for deflecting optical beams from/to optical fibers were investigated. Fiber aligning grooves and passive mirror-like planes were realized by wet micromachining of (1 0 0) silicon in KOH–IPA and TMAH–IPA systems. Implementation of Triton-x-100 surfactant as an additive to 25% TMAH in anisotropic etching of {1 1 0} silicon passive mirror planes is reported and discussed. It was found that Triton-x-100 contents in the range of 10–200 ppm to the 25% TMAH–water etchant significantly increase the anisotropy mostly by decreasing the {1 1 0} etch rate and retaining the {1 0 0} etch rate. It is also shown that {1 1 0} surface roughness is substantially improved compared to two other etching systems. Furthermore, efficient convex corner underetching reduction is demonstrated. The results of optical characterization of passive mirrors with 632 nm incident light show reduced scattering of reflected optical beam due to improved microroughness for mirrors made by TMAH–Triton. For the reflection of the optical beam with 1.33 µm and 1.54 µm wavelengths, sputtered layer of gold is used as reflective coating on silicon mirrors thus increasing the reflected optical beam intensity by an additional 8%.

Exosomes, a type of nanovesicle, are distinct cellular entities specifically capable of carrying various cargos between cells. It has been hypothesized that exosomes, as an enriched source of biomolecules, may serve as biomarkers for various diseases. This review introduces general aspects of exosomes, presents the challenges in exosome research, discusses the potential of exosomes as biomarkers, and describes the contribution of microfluidic technology to enable their isolation and analysis for diagnostic and disease monitoring. Additionally, clinical applications of exosomes for diagnostic purposes are also summarized.

Investigation was focused on the formation of {311} planes by wet anisotropic etching of (100) silicon and, in particular, on the characterization by means of surface roughness, etch rates and related convex and concave corner dynamic behaviour during maskless etching. KOH and TMAH water solutions were tested for their influence on previously mentioned parameters as well as the effect of isopropyl alcohol (IPA). It was found that convex corner undercutting is significantly reduced if {311} bounding planes are utilized instead of {111} bounding planes. For shallow structures a self-compensation can be obtained with KOH and when certain conditions are met, also with TMAH. The rounding of the concave corner that arises through prolonged etching is reported, which is particularly emphasized in KOH and less in TMAH etchant. Addition of IPA in maskless mode is experimentally investigated, showing minor influence on etching conditions and on reducing the undercut of convex corners. Etch rates and dimensional control of some microstructures are discussed and presented comparatively for different etching systems in a temperature range of 50-100 °C. By evaluation of surface quality with a surface profiler and SEM, it was found that the smoothest surface was achieved by etching in TMAH. The role of solution temperature in surface roughness was found to be of minor importance, as well as the stirring of the solution. It was determined that the IPA additive increases roughness when used with KOH, while with TMAH, the influence on roughness of the {311} planes is insignificant.

DMILL bipolar transistors (npn) were exposed to 24 GeV protons and fast and thermal neutrons to fluences up to 6 10 14 n/cm 2 . Transistor common emitter current gain ( = I collector I base ) was measured after irradiations. It was found that degradation scales as 1(1 ) = k T 8 T where 8 T is the fluence of thermal neutrons and as 1(1 ) = k eq 8 eq , with 8 eq 1-MeV equivalent fluence, if transistors are irradiated with protons or fast neutrons. Large damage factor k T 3 k eq was measured. Thermal neutrons do not have sufficient energy to displace a Si atom. Their damage mechanism is, therefore, identified with 10 B(n ) 7 Li reaction from which energetic and Li particles produce bulk damage in the base of the device. Boron is used as the base dopant in these transistors having also highly doped regions below base contacts. Irradiations with neutrons with energies distributed from thermal to fast show that gain degradation adds up as 1(1 ) = k T 8 T + k eq 8 eq .

An experimental study of in vivo insulin delivery through microinjection by using hollow silicon microneedle array is presented. A case study was carried out on a healthy human subject in vivo to determine the influence of delivery parameters on drug transfer efficiency. As a microinjection device, a hollow microneedle array (13 × 13 mm2) having 100 microneedles (220 µm high, 130 µm-outer diameter and 50 µm-inner diameter) was designed and fabricated using classical microfabrication techniques. The efficiency of the delivery process was first characterized using methylene blue and a saline solution. Based on these results, the transfer efficiency was found to be predominantly limited by the inability of viable epidermis to absorb and allow higher drug transport toward the capillary-rich region. Two types of fast-acting insulin were used to provide evidence of efficient delivery by hollow MNA to a human subject. By performing blood analyses, infusion of more-concentrated insulin (200 IU/mL, international units (IU)) exhibited similar blood glucose level drop (5–7%) compared to insulin of standard concentration (100 IU/mL), however, significant increase of serum insulin (40–50%) with respect to the preinfusion values was determined. This was additionally confirmed by a distinctive increase of insulin to C-peptide ratio as compared to preinfusion ratio. Moreover, we noticed that this route of administration mimics a multiple dose regimen, able to get a “steady state” for insulin plasma concentration.