We review the current state of optical methods for sensing oxygen. These have become powerful alternatives to electrochemical detection and in the process of replacing the Clark electrode in many fields. The article (with 694 references) is divided into main sections on direct spectroscopic sensing of oxygen, on absorptiometric and luminescent probes, on polymeric matrices and supports, on additives and related materials, on spectroscopic schemes for read-out and imaging, and on sensing formats (such as waveguide sensing, sensor arrays, multiple sensors and nanosensors). We finally discuss future trends and applications and summarize the properties of the most often used indicator probes and polymers. The ESI† (with 385 references) gives a selection of specific applications of such sensors in medicine, biology, marine and geosciences, intracellular sensing, aerodynamics, industry and biotechnology, among others.

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Optical methods for sensing and imaging oxygen: materials, spectroscopies and applications

Porphyrins and related macrocycles have been intensively exploited as sensing materials in chemical sensors, since in these devices they mimic most of their biological functions, such as reversible binding, catalytic activation, and optical changes. Such a magnificent bouquet of properties allows applying porphyrin derivatives to different transducers, ranging from nanogravimetric to optical devices, also enabling the realization of multifunctional chemical sensors, in which multiple transduction mechanisms are applied to the same sensing layer. Potential applications are further expanded through sensor arrays, where cross-selective sensing layers can be applied for the analysis of complex chemical matrices. The possibility of finely tuning the macrocycle properties by synthetic modification of the different components of the porphyrin ring, such as peripheral substituents, molecular skeleton, coordinated metal, allows creating a vast library of porphyrinoid-based sensing layers. From among these, one can...

Porphyrinoids for Chemical Sensor Applications.

Chronic non-healing wounds challenge tissue regeneration and impair infection regulation for patients afflicted with this condition. Next generation wound care technology capable of in situ physiological surveillance which can diagnose wound parameters, treat various chronic wound symptoms, and reduce infection at the wound noninvasively with the use of a closed loop therapeutic system would provide patients with an improved standard of care and an accelerated wound repair mechanism. The indicating biomarkers specific to chronic wounds include blood pressure, temperature, oxygen, pH, lactate, glucose, interleukin-6 (IL-6), and infection status. A wound monitoring device would help decrease prolonged hospitalization, multiple doctors' visits, and the expensive lab testing associated with the diagnosis and treatment of chronic wounds. A device capable of monitoring the wound status and stimulating the healing process is highly desirable. In this review, we discuss the impaired physiological states of chronic wounds and explain the current treatment methods. Specifically, we focus on improvements in materials, platforms, fabrication methods for wearable devices, and quantitative analysis of various biomarkers vital to wound healing progress.

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Wearable Technology for Chronic Wound Monitoring: Current Dressings, Advancements, and Future Prospects.

Functionalized mesoporous silica materials (MSMs) are extensively investigated in sensing science due to their diverse structural and optical properties including tunable pore size, modifiable surface properties, and excellent accessibility to active sites. In the last few years, great efforts have been devoted to developing modification methods for MSMs for sensing applications with augmented sensitivity, super selectivity, as well as targeting capability, and multimodal capabilities. The functional group, structure, morphology, and component levels in the assembly of heterostructures of MSMs are a key for high sensing performance. As the development of mesoporous silica‐based sensing materials progresses, diverse functional units and materials are rationally implemented into the mesoporous structures. These heterostructures can maintain the excellent structural features of mesoporous silica and the optical properties of the functional units simultaneously, which shows the advantages of photostability, design flexibility, and multifunctionality. Here, an up‐to‐date overview of the fabrication strategies, the properties, and the sensing mechanisms of optical heterostructures based on MSMs is provided. A number of crucial sensing domains, including ionic, molecules, temperature, and biological species are highlighted. Finally, the prospects and potential sensing applications of mesoporous silica‐based optical heterostructures are discussed.

Interfacial Assembly of Mesoporous Silica-Based Optical Heterostructures for Sensing Applications

Fabrication of 1,2-dichlorobenzene sensor based on mesoporous MCM-41 material

A novel luminescent platinum(II) complex platinum 5,10,15,20-tetra{4-[(N-carbazyl)butyloxyphenyl]}porphyrin (PtTCBPyP) has been synthesized and characterized by H-1 NMR, elemental analysis, IR and UV-vis. The platinum porphyrin is assembled with mesoporous silica SBA-15 and MCM-41 resulting in the assembly materials PtTCBPyP/SBA-15 and PtTCBPyP/MCM-41. The luminescence of platinum porphyrin complex/silicate assemble materials can be quenched by molecular oxygen with very high response (I-0/I-100 > 8700 for PtTCBPyP/SBA-15(20 mg/g) and I-0/I-100 > 3800 for PtTCBPyP/MCM-41(20 mg/g)), indicating that platinum porphyrin complex/silicate systems can be employed to develop high performance oxygen sensors. Among this assembly system, PtTCBPyP/SBA-15(20 mg/g) exhibits the highest response of platinum porphyrin complex/silica. (C) 2013 Elsevier B.V. All rights reserved.

Yao Li

Papers

Synthesis, characterization, and oxygen sensing properties of functionalized mesoporous silica SBA-15 and MCM-41 with a Pt(II)-porphyrin complex