DNA Tetrahedra-Cross-linked Hydrogel Functionalized Paper for Onsite Analysis of DNA Methyltransferase Activity Using a Personal Glucose Meter

Abstract

Despite the recent developments on the construction of point-of-care testing (POCT) devices, it is still a big challenge to build portable POCT tools for simple, sensitive, selective, and quantitative determination of disease-related biomarkers. With this in mind, we developed a simple and userfriendly POCT tool for onsite analysis of DNA adenine methyltransferase (Dam) activity by using DNA tetrahedra-based hydrogel to trap glucose-producing enzymes for target recognition and signal transduction. The enzyme-encapsulated DNA hydrogel and the substrate of enzyme were separately modified on papers and then combined onto a commercial glucose test strip for the sensitive evaluation of Dam activity via using a personal glucose meter (PGM) for quantitative signal readout. Taking advantage of the great amount of enzyme entrapped in DNA hydrogel and the high signal amplification ability of enzyme, this POCT tool is capable of highly sensitive and selective determination of Dam activity with a direct detection limit down to 0.001 U/mL, which is superior to that of most previously reported biosensors. Furthermore, this device can also be applied to screen inhibitor and analyze Dam activity in spiked serum samples, indicating the great potential for clinical practice and diagnostic applications. Additionally, all the reactions for Dam assay are performed on paper, which is simple and deliverable to end-users for medical diagnostics at home or in-field.

Recent Advances of DNA Tetrahedra for Therapeutic Delivery and Biosensing

“…The imaging probe had the ability to efficiently discriminate between a variety of live cancer cells and normal cells by monitoring the fraction of acceptors and donors (F a /F d ) highlighting the dynamic imaging capabilities of the system. DTNPs have also been exploited for the detection of DNA methyltransferase activity for both diagnostic and therapeutic applications [47,48] . Recently Gao et al.…”

“…Recently Gao et al. designed a paper functionalized TDN‐hydrogel network with encapsulated amyloglucosidases (AMG) to monitor on‐site Dam activity using a personal glucose meter [48] . Polymerization of the hydrogel was achieved by combining two TDNs with either poly(A) or poly(T) tails extending from all corners in the presence of AMG on a round paper forming the crosslinked network (Figure 4B).…”

“…Reproduced with permission from ref. [48]; copyright: 2020, American Chemical Society. C) Quantification of Ca 2+ and pH with a TDN by fluorescence.…”

Personal Glucose Meter for α-Glucosidase Inhibitor Screening Based on the Hydrolysis of Maltose

“…As point-of-care diagnostic tools, personal glucose meters (PGMs) are well-placed to be repurposed for on-site and real-time molecule detection owing to their portability, low cost, simplicity, inherent quantification, and high selectivity [ 17 ]. Furthermore, the use of PGMs for the detection of biomarkers other than glucose are also extensively developed, such as enzymes [ 18 ], mycotoxins [ 19 ], metal ions [ 20 ], protein, and DNA [ 21 , 22 ]. Most published methods use enzymes or nanoparticles containing glucose to produce glucose that is ultimately measured by PGM.…”

Smartphone and Paper-Based Fluorescence Reader: A Do It Yourself Approach

“…Highly sensitive point-of-care biosensing can be critical to enable timely healthcare decisions [7][8][9][10]. Quantum dot (QD) nanocrystals have been proven advantageous in these approaches due to their highly efficient fluorescence, size-tunable Gaussian emission spectrum, excellent stability against photobleaching, large Stokes shift and low background signal [11][12][13].…”