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Voltammetric sensors based on phthalocyanines have been used to detect a variety of compounds. In this paper, the state of the art of sensors prepared using classical techniques will be revised. Then, new strategies to improve the performance of the sensors will be described using as example sensors chemically modified with lutetium bisphthalocyanine (LuPc${}_2)$ dedicated to the detection of phenols of interest in the food industry. Classical LuPc₂ carbon paste electrodes can detect phenols such as catechol, caffeic acid or pyrogallol with limits of detection in the range of 10${}^{-4}$–10${}^{-5}$ M. The performance can be improved by using nanostructured Langmuir–Blodgett (LB) or Layer by Layer (LbL) films. The enhanced surface to volume ratio produce an increase in the sensitivity of the sensors. Limits of detection of 10${}^{-5}$–10${}^{-7}$ M are attained, which are one order of magnitude lower than those obtained using conventional carbon paste electrodes. Moreover, these techniques can be used to co-immobilize two electrocatalytic materials in the same device. The limits of detection obtained in LB sensors combining LuPc₂/AuNPs or LuPc₂/CNT are further improved. Finally, the LB technique has been used to prepare biosensors where a phenol oxydase (such as tyrosinase or lacasse) is immobilized in a biomimetic environment that preserves the enzymatic activity. Moreover, LuPc₂ can be co-immobilized with the enzyme in a lipidic film formed by arachidic acid (AA). LuPc₂ can act as an electron mediator facilitating the electron transfer. These biomimetic sensors formed by LuPc₂/AA/enzyme show Limits of detection of 10${}^{-8}$ M and an enhanced selectivity.

With the aim of assessing the role of the chemical structure of the photosensitizer on the photophysical and photochemical properties of the final nanoparticle suspension, we have investigated a series of poly-(ethylene glycol)-poly-($D,L$-lactide-co-glycolide) nanoparticles containing a hydrophobic or a hydrophilic porphyrin covalently conjugated to the nanoparticle. Covalent conjugation responded to the objective of trying to improve photosensitizer loading in these nanoparticles, especially for hydrophilic photosensitizers, but also enabled the porphyrins to remain attached to the nanoparticle without necessarily being inside the poly-($D,L$-lactide-co-glycolide) core. This strategy has provided valuable information about the dependence of the photophysical and singlet oxygen photosensitizing properties of the suspensions on the nature of the photosensitizer. It is concluded that poly-($D,L$-lactide-co-glycolide) nanoparticles with covalently-bound hydrophilic porphyrins show superior singlet oxygen photosensitizing ability.

Water and air pollution are among the major environmental challenges of this era. Waste management, economic sustainable development and renewable energy are unavoidable concomitant considerations. Over the past five years, nanosized metal-organic frameworks (nano-MOFs) have been developed for the elimination of pollutants in wet media and air-born toxins using the highly efficient reactive oxygen species (ROS) of type I (H₂O₂, •OH, O${}_2^{•-})$ and of type II (¹O${}_2)$. The ROS are catalytically and efficiently generated through photosensitization, and porphyrins and metalloporphyrins are pigments of choice for this purpose. This short review summarizes the fundamentals of ROS generation by porphyrin-based nano-MOFs (mainly through the formation of ROS type II) and their composites (leading to ROS type I), which includes energy and electron transfer processes, and their applications in these environmental issues.

In this paper, the MHD Jeffery–Hamel flow with cu-water nanofluid between two smooth rectangular walls with the transverse magnetic field is studied. Differential transform method (DTM) is used to obtain the velocity profile of Jeffery–Hamel flow in both convergent and divergent channels for different values of Reynolds number and Hartmann number. Finally, to examine the accuracy and the validity of the method, the obtained results have been compared with the available collation method results.

This study outlines a drug delivery mechanism that utilizes two independent vehicles, allowing for delivery of chemically and physically distinct agents. The mechanism was utilized to deliver a new anti-cancer combination therapy consisting of piperlongumine (PL) and TRAIL to treat PC3 prostate cancer and HCT116 colon cancer cells. PL, a small-molecule hydrophobic drug, was encapsulated in poly (lactic-co-glycolic acid) (PLGA) nanoparticles. TRAIL was chemically conjugated to the surface of liposomes. PL was first administered to sensitize cancer cells to the effects of TRAIL. PC3 and HCT116 cells had lower survival rates in vitro after receiving the dual nanoparticle therapy compared to each agent individually. In vivo testing involved a subcutaneous mouse xenograft model using NOD-SCID gamma mice and HCT116 cells. Two treatment cycles were administered over 48 hours. Higher apoptotic rates were observed for HCT116 tumor cells that received the dual nanoparticle therapy compared to individual stages of the nanoparticle therapy alone.

Stress detection and monitoring have attracted substantial research interests due to stress being a risk factor for health disorders and economic burdens. In particular, the steroid hormone cortisol plays an important role both as an indicator of stress and a coordinator of downstream physiological responses. Recent years have witnessed a flourishing of cortisol biosensors and bioassays based on various physical principles. In this review, we first provide an overview of cortisol function and its presence in different biological matrices. Next, we discuss the existing range of cortisol biosensors, from their sensing principles (i.e. chromogenic, nanoparticle-based colorimetric and fluorometric, surface-enhanced Raman spectroscopy, surface plasma resonance spectroscopy, and electrochemical sensors), performances (sensitivity, selectivity, portability, etc.), and applications. We particularly correlate the sensing performances and their suitability for point-of-care diagnostics with sensor principles and the use of different affinity ligands, such as antibodies, aptamers, molecular imprint, and even 2D materials such as MXenes. Finally, we discuss the challenges and perspectives of future high-performing cortisol sensors for a wider range of applications in human and animal stress monitoring.