The spleen is a secondary lymphoid organ specialized in the filtration of senescent, damaged, or infected red blood cells.

Nanostructure-based plasmonic biosensors have quickly positioned themselves as interesting candidates for the design of portable optical biosensor platforms considering the potential benefits they can offer in integration, miniaturization, multiplexing, and real-time label-free detection. We have developed a simple integrated nanoplasmonic sensor taking advantage of the periodic nanostructured array of commercial Blu-ray discs. Sensors with two gold film thicknesses (50 and 100nm) were fabricated and optically characterized by varying the oblique-angle of the incident light in optical reflectance measurements. Contrary to the use normal light incidence previously reported with other optical discs, we observed an enhancement in sensitivity and a narrowing of the resonant linewidths as the light incidence angle was increased, which could be related to the generation of Fano resonant modes. The new sensors achieve a figure of merit (FOM) up to 35 RIU-1 and a competitive bulk limit of detection (LOD) of 6.3×10-6 RIU. These values significantly improve previously reported results obtained with normal light incidence reflectance measurements using similar structures. The sensor has been combined with versatile, simple, ease to-fabricate microfluidics. The integrated chip is only 1cm2 (including a PDMS flow cell with a 50µm height microfluidic channel fabricated with double-sided adhesive tape) and all the optical components are mounted on a 10cm×10cm portable prototype, illustrating its facile miniaturization, integration and potential portability. Finally, to assess the label-free biosensing capability of the new sensor, we have evaluated the presence of specific antibodies against the GTF2b protein, a tumor-associate antigen (TAA) related to colorectal cancer. We have achieved a LOD in the pM order and have assessed the feasibility of directly measuring biological samples such as human serum.

Understanding the basic mechanisms of neural regeneration after injury is a pre-requisite for developing appropriate treatments. Traditional approaches to model axonal lesions, such as high intensity power laser ablation or sharp metal scratching, are complex to implement, have low throughputs, and generate cuts that are difficult to modulate. We present here a novel reproducible microfluidic approach to model in vitro mechanical lesion of tens to hundreds of axons simultaneously in a controlled manner. The dimensions of the induced axonal injury and its distance from the neuronal cell body are precisely controlled while preserving both the proximal and distal portions of axons. We have observed that distal axons undergo Wallerian-like anterograde degeneration after axotomy; in contrast, proximal portions of the axons remain un-degenerated, possessing the potential to re-grow. More importantly, surpassing the previous axotomy methods performed in Petridishes in which local microenvironments cannot be tailored, our platform holds the capability to implement fine-tuned treatments to lesioned axon stumps in a local, controlled manner. Specifically, molecules such as chondroitin sulphate proteoglycans and its degrading enzyme chondroitinase ABC, hydrogels, and supporting cells have been shown to be deliverable to the lesioned site of injured axons. In addition, this system also permits double interventions at the level of the lesioned axons and the perikaryon. This proves the potential of our model by demonstrating how axonal regrowth can be evaluated under circumstances that are better mimics of biological problems. We believe that this novel mechanical microfluidic axotomy approach is easy to perform, yields high throughput axon lesions, is physiologically relevant, and offers a simplified platform for screening of potential new neurological drugs.

Bacteria concentration and detection is time-consuming in regular microbiology procedures aimed to facilitate the detection and analysis of these cells at very low concentrations. Traditional methods are effective but often require several days to complete. This scenario results in low bioanalytical and diagnostic methodologies with associated increased costs and complexity. In recent years, the exploitation of the intrinsic electrical properties of cells has emerged as an appealing alternative approach for concentrating and detecting bacteria. The combination of dielectrophoresis (DEP) and impedance analysis (IA) in microfluidic on-chip platforms could be key to develop rapid, accurate, portable, simple-to-use and cost-effective microfluidic devices with a promising impact in medicine, public health, agricultural, food control and environmental areas. The present document reviews recent DEP and IA combined approaches and the latest relevant improvements focusing on bacteria concentration and detection, including selectivity, sensitivity, detection time, and conductivity variation enhancements. Furthermore, this review analyses future trends and challenges which need to be addressed in order to successfully commercialize these platforms resulting in an adequate social return of public-funded investments.