Biomarker Detection in Early Diagnosis of Cancer: Recent Achievements in Point-of-Care Devices Based on Paper Microfluidics.

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.

Portable quantification of silver ion by using personal glucose meter (PGM) and magnetite cross-linked invertase aggregates (MCLIA).

Heavy metal detection is critical due to its harmful effects on human health and the ecosystem. Enzyme-based platforms attract attention for heavy metal detection such as silver, a toxic metal, due to being small, portable, and requiring only essential equipment compared with the basic analytical methods. In this study, magnetic cross-linked invertase aggregates (MCLIA) were developed for the first time as an enzyme-based signaling platform to detect Ag+ using a personal glucose meter (PGM). EDX, FTIR, and VSM results depicted that MCLIA was successfully developed and exhibits super-paramagnetism. In addition, MCLIA selectively detected the Ag+ at a sensitivity of 1.2 inhibition rate/µM in a linear range from 5 to 70 µM with a detection limit of 4.6 µM and IC50 value of 42.3 µM. These findings strongly indicate that MCLIA is applicable as a signal platform for portable quantification of other analytes that inhibits the invertase enzyme.