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Synthetic hydrogels composed of polymer pore frames are commonly used in medicine, from pharmacologically targeted drug delivery to the creation of bioengineering constructions used in implantation surgery. Among various possible materials, the most common are poly-[N(2-hydroxypropyl)methacrylamide] (pHPMA) derivatives. One of the pHPMA derivatives is biocompatible hydrogel, NeuroGel. Upon contact with nervous tissue, the NeuroGel’s structure can support the chemical and physiological conditions of the tissue necessary for the growth of native cells. Owing to the different pore diameters in the hydrogel, not only macromolecules, but also cells can migrate. This study evaluated the differentiation of bone marrow stromal cells (BMSCs) into neurons, as well as the effectiveness of using this biofabricated system in spinal cord injury in vivo. The hydrogel was populated with BMSCs by injection or rehydration. After cultivation, these fragments (hydrogel + BMSCs) were implanted into the injured rat spinal cord. Fragments were immunostained before implantation and seven months after implantation. During cultivation with the hydrogel, both variants (injection/rehydration) of the BMSCs culture retained their viability and demonstrated a significant number of Ki-67-positive cells, indicating the preservation of their proliferative activity. In hydrogel fragments, BMSCs also maintained their viability during the period of cocultivation and were Ki-67-positive, but in significantly fewer numbers than in the cell culture. In addition, in fragments of hydrogel with grafted BMSCs, both by the injection or rehydration versions, we observed a significant number up to 57%–63.5% of NeuN-positive cells. These results suggest that the heterogeneous pHPMA hydrogel promotes neuronal differentiation of bone marrow-derived stromal cells. Furthermore, these data demonstrate the possible use of NeuroGel implants with grafted BMSCs for implantation into damaged areas of the spinal cord, with subsequent nerve fiber germination, nerve cell regeneration, and damaged segment restoration.

Synthetic hydrogels composed of polymer pore frames are commonly used in medicine, from pharmacologically targeted drug delivery to the creation of bioengineering constructions used in implantation surgery. Among various possible materials, the most common are poly-[N(2-hydroxypropyl)methacrylamide] (pHPMA) derivatives. One of the pHPMA derivatives is biocompatible hydrogel, NeuroGel. Upon contact with nervous tissue, the NeuroGel's structure can support the chemical and physiological conditions of the tissue necessary for the growth of native cells. Owing to the different pore diameters in the hydrogel, not only macromolecules, but also cells can migrate. This study evaluated the differentiation of bone marrow stromal cells (BMSCs) into neurons, as well as the effectiveness of using this biofabricated system in spinal cord injury

This paper will discuss the challenges and solutions required for large scale production of more than 250 000 Fabry-Perot sensors per year, demonstrating that automated production of large-volume fiber optic sensing is now a reality. Medical and industrial applications requiring large volume production are also explored.

Penetration of optical-fibre sensors into the medical market has been slow because of high costs and long regulatory procedures. Today, however, an increasing number of life-saving medical procedures are benefiting from the advantages that these tiny sensors can bring.

Mainly three technologies are presently commercially available for pressure measurement with fiber-optic sensors: intensity-based, fiber Bragg gratings and Fabry-Perot. The first one is probably the simplest and the cheapest but it is limited to applications where having 2 fixed or up to 4 flexible fibers is not an issue, whereas the two other technologies require only one fiber. With generally low sensitivity to pressure and prohibitive cost for non multiplexed measurements, fiber Bragg grating pressure sensors are still limited to marginal applications. Fabry-Perot technology is the best compromise offering at affordable price a great flexibility in terms of pressure ranges, high sensitivity and miniature size suitable for most applications including disposable medical devices.

Medical applications represent a unique chance of expansion for the optical fiber sensors (OFS) market that was confined so far mostly in niche applications where higher technological costs were justified by OFS distinctive advantages. Single use medical devices integrating OFS could however generate a significant growth for this type of technology. Thanks to cost reductions derived from the success of optical fiber used in the telecom industry, it is now possible to produce competitive disposable OFS for clinical environment. Cost reduction is nevertheless not the only challenge for this type of application: materials bio-compatibility and sterilization resistance, packaging issues, design considerations for end-user acceptance and operational simplicity, technology reliability including connectivity and sensor performances, manufacturing process monitoring and outstanding quality control, are among few of the problems that have to be considered to address correctly the complex medical market with successful disposable OFS devices. With a clear understanding of the needs and challenges of clinical applications, it is easier to respond to this reality and to offer commercially suitable solutions.

We present how fiber-optic temperature or pressure sensors could be applied to minimally invasive diagnostics and therapies. For instance a miniature pressure sensor based on micro-optical mechanical systems (MOMS) could solve most of the problems associated with fluidic pressure transduction presently used for triggering purposes. These include intra-aortic balloon pumping (IABP) therapy and other applications requiring detection of fast and/or subtle fluid pressure variations such as for intracranial pressure monitoring or for urology diagnostics. As well, miniature temperature sensors permit minimally invasive direct temperature measurement in diagnostics or therapies requiring energy transfer to living tissues. The extremely small size of fiber-optic sensors that we have developed allows quick and precise in situ measurements exactly where the physical parameters need to be known. Furthermore, their intrinsic immunity to electromagnetic interference (EMI) allows for the safe use of EMI-generating therapeutic or diagnostic equipments without compromising the signal quality. With the trend of ambulatory health care and the increasing EMI noise found in modern hospitals, the use of multi-parameter fiber-optic sensors will improve constant patient monitoring without any concern about the effects of EMI disturbances. The advantages of miniature fiberoptic sensors will offer clinicians new monitoring tools that open the way for improved diagnostic accuracy and new therapeutic technologies.

Birefringent porous glass integrated between two plastic optical fibers terminated by crossed Polaroid™ films was used as a low-cost end-of-service-life indicator (ESLI) for organic vapor cartridges. Birefringence is significantly reduced when volatile compounds condense into the anisotropic porous structure. Such changes could easily be quantified using a low-cost light source and detector and very simple light intensity analysis. We showed that such sensors integrated into an experimental organic vapor cartridge could easily detect the progression of low concentrations of solvents (such as 50 ppm of toluene) into the activated charcoal cartridge and thus truly be used as an ESLI. Since such robust sensors could detect broadband solvents by simple physical condensation similar to the trapping phenomena of activated carbon, they are probably ideal candidates for such application.