Abstract
The design and synthesis of artificial receptors based on molecular imprinting (MI) technology for the development of a new MIP-based biosensor for detection of the stress biomarker a-amylase in human saliva in point-of-care (PoC) applications is described in this work. The portable electrochemical devices for monitoring a-amylase consists of cost-effective and disposable gold screen-printed electrodes (AuSPEs). To build the electrochemical device, the template biomolecule was firstly immobilized directly over the working area of the gold chip previously activated with a self-assembled monolayer (SAM) of cysteamine (CA). Then, pyrrole (Py) monomer was selected as building block of a polymeric network prepared by CV electropolymerization. After the electropolymerization process, the enzyme was removed from the polymer film in order to build the specific recognition sites for the target enzyme. The MIP biosensor showed a very wide linear concentration range (between 3.0 × 10-4 to 0.60 mg mL-1 in buffer solution and between 3.0 × 10-4 to 3.0 × 10-2 mg mL-1 in human saliva) and low detection levels were achieved (LOD < 3.0 × 10-4 mg mL-1) using square wave voltammetry (SWV) as the electroanalytical technique.

Abstract
In this work, we describe an innovative methodology based on combined surface plasmon resonance (SPR) and electrochemical responses (eSPR) in the same immunoassay for screening CA 15-3 cancer biomarker with high sensitivity (and selectivity), in a very simple, label-free, accurate, and fully automated manner. Detection was achieved by performing two simple steps. In the first step, direct SPR was used to monitor CA 15-3 interaction with surface immobilized antibody. Two linear response ranges were obtained and the detection limit achieved is poor (LOD of 21 U mL(-1)). However, in the second detection step, electrochemical measurements at the SPR gold surface were performed to measure the decrease of redox probe peak current upon antigen-antibody interaction, providing a suitable amplification strategy to lower detection levels of CA 15-3 (LOD of 0.0998 U mL(-1)), without the need of additional complex and/or expensive amplification steps to enhance the sensitivity. Moreover, selectivity studies were performed against other common cancer biomarkers and the results showed that the eSPR immunosensor is selective for the CA 15-3 protein. Finally, the clinical applicability of the developed eSPR biosensing methodology was successfully applied to detect CA 15-3 in human serum samples at clinically relevant levels due to the high sensitivity of electrochemical readout. The same concept may be further extended to other proteins of interest.

Abstract
With the advent of personalized medicine, there is a movement to develop "smaller" and "smarter" microdevices that are able to distinguish similar cancer subtypes. Tumor cells display major differences when compared to their natural counterparts, due to alterations in fundamental cellular processes such as glycosylation. Glycans are involved in tumor cell biology and they have been considered to be suitable cancer biomarkers. Thus, more selective cancer screening assays can be developed through the detection of specific altered glycans on the surface of circulating cancer cells. Currently, this is only possible through time-consuming assays. In this work, we propose the "intelligent" Lab on Fiber (iLoF) device, that has a high-resolution, and which is a fast and portable method for tumor single-cell type identification and isolation. We apply an Artificial Intelligence approach to the back-scattered signal arising from a trapped cell by a micro-lensed optical fiber. As a proof of concept, we show that iLoF is able to discriminate two human cancer cell models sharing the same genetic background but displaying a different surface glycosylation profile with an accuracy above 90% and a speed rate of 2.3 seconds. We envision the incorporation of the iLoF in an easy-to-operate microchip for cancer identification, which would allow further biological characterization of the captured circulating live cells.

Abstract
First order off-axis fiber Bragg gratings (FBGs) were fabricated in a standard single mode fiber (SMF-28e) through femtosecond laser direct writing. A minimum offset distance between the grating and core center of 2.5 mu m was found to create a multimode section, which supports two separate fiber modes (LP0,1 and LP1,1), each split into two degenerate polarization modes. The resulting structure breaks the cylindrical symmetry of the fiber, introducing birefringence (approximate to 10(-4)) resulting in a polarization dependent Bragg wavelength for each mode. Based on the modal and birefringence behavior, three off-axis FBGs were fabricated with 3.0, 4.5 and 6.0 mu m offsets from the core center, and then characterized in strain, temperature, and curvature. The tested off-axis FBGs exhibited a similar strain sensitivity of similar to 1.14 pm/mu epsilon and a temperature sensitivity of similar to 12 pm/C. The curvature and orientation angle were simultaneously monitored by analyzing the intensity fluctuation and the wavelength shift of the LP1,1 Bragg resonance. A maximum curvature sensitivity of 0.53 dB/m(-1) was obtained for the off-axis FBG with a 3.0 mu m offset.

Abstract

Abstract
Long Period Fibre Gratings (LPFGs) were fabricated by femtosecond (fs) laser direct writing in a standard single-mode fibre (SMF-28e) to measure variations in the surrounding refractive index (SRI). The sensing sensitivity of these structures was optimized with the deposition of homogeneous thin layers of titanium dioxide (TiO2) by physical vapour deposition (PVD) process. A set of LPFGs were coated with different thickness layers of TiO2, and the spectral features were monitored for different SRI solutions. The wavelength shift and the optical power variation of the LPFG minimum attenuation band were measured achieving sensitivities of similar to 570 nm/RIU at using SRI near to 1.3600 in the case of the LPFG coated with 60 nm of TiO2, a 10-fold increase over the corresponding for a bare LPFG. For SRI values higher than the cladding refractive index, a sensitivity over similar to 3000 nm/RIU was determined for 30 nm of TiO2 thick film, a region where the bare LPFGs are useless. For 30 nm of TiO2, the optical power variation follows a quasi-linear function of the SRI, with a range of similar to 10 dB. Moreover, values as high as 50 and 120 dB/RIU at 1.3200 and 1.4200, respectively, can be obtained by choosing the proper film thickness. Preliminary studies revealed that coating fs-laser direct writing LPFGs with titanium dioxide improves their performance.