In this Feature, the most recent developments as well as "pros and cons" in smartphone sensing, which have been developed using various functional nanoparticles in paper-based sensing systems, will be discussed. Additionally, smart phone sensing and POC combination as a potential tool that opens a gate for knowledge flow "from lab scale data to public use" will be evaluated.

During the last decade, progress has been made in the on‐site detection of abused drug use. Herein, we present an electrochemical biosensor for the detection of one of the synthetic cannabinoids (SCs), JWH‐073, using poly (methyl methacrylate) (PMMA) hyperbranched copolymer (HBC) as a base coating and antibody molecules to bind the JWH‐073 to the surface. Modification of the surface is proved with various techniques such as differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectrometry. The limit of detection and linearity (in logarithmic scale) for JWH‐073 were found to be 31.87 ng/mL and 25–500 ng/mL, respectively. The selectivity of the proposed biosensor was also tested in the presence of interfering molecules and the response was much higher for JWH‐073 in all measurements. In the final part of the study, synthetic urine was tested with the device and the relative standard deviation value was calculated to be less than 5.0 %. The confirmation of data from the resulting bio‐platform was performed via LC‐QTOF/MS. This work is the first of its kind, a novel, rapid, cost‐effective sensing platform for the detection of the SC.

A novel catechol-bearing polypeptide (CtP) was synthesized and used as a component of electrochemical biosensor involving both enzymatic activity and affinity-based sensing systems. Glucose oxidase (GOx) and anti-immunoglobulin G (Anti-IgG) were selected as model biorecognition elements for the selective analysis of glucose and IgG. Step-by-step surface modifications were followed using various techniques such as cyclic voltammetry (CV) and electrochemical impedance spectrometry (EIS) as well as X-ray photoelectron spectroscopy (XPS). Additionally, contact angles were measured in order to observe surface properties. Amperometric measurements using the GOx biosensor were performed at -0.7 V by following the oxygen consumption due to the enzymatic reaction in different glucose concentrations. Affinity-based interactions via IgG sensor were monitored using the differential pulse voltammetry (DPV) technique. As the "surface design with CtP" approach employed herein is generally applicable and easily adaptable to obtain functional matrices for biomolecule immobilization, CtP-coated surfaces can be promising platforms for the fabrication of various biobased sensing systems.

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Microfluidics is very crucial in lab-on-a-chip systems for carrying out operations in a large-scale laboratory environment on a single chip. Microfluidic systems are miniaturized devices in which the fluid behavior and control can be manipulated on a small platform, with surface forces on the platform being greater than volumetric forces depending on the test method used. In recent years, paper-based microfluidic analytical devices (μPADs) have been developed to be used in point-of-care (POC) technologies. μPADs have numerous advantages, including ease of use, low cost, capillary action liquid transfer without the need for power, the ability to store reagents in active form in the fiber network, and the capability to perform multiple tests using various measurement techniques. These benefits are critical in the advancement of paper-based microfluidics in the fields of disease diagnosis, drug application, and environment and food safety. Cancer is one of the most critical diseases for early detection all around the world. Detecting cancer-specific biomarkers provides significant data for both early diagnosis and controlling the disease progression. μPADs for cancer biomarker detection hold great promise for improving cure rates, quality of life, and minimizing treatment costs. Although various types of bioanalytical platforms are available for the detection of cancer biomarkers, there are limited studies and critical reviews on paper-based microfluidic platforms in the literature. Hence, this article aims to draw attention to these gaps in the literature as well as the features that future platforms should have.