title: Paper-Based Device for Rapid Visualization of NADH Based on Dissolution of Gold Nanoparticles.
abstract: We describe a paper-based device that enables rapid and sensitive room-temperature detection of dihydronicotinamide adenine dinucleotide (NADH) via a colorimetric readout and demonstrate its value for monitoring NAD+-driven enzymatic reactions. Our system is based on NADH-mediated inhibition of gold nanoparticle (AuNPs) dissolution in a Au3+-cetyltrimethylammonium bromide (CTAB) solution. We fabricated a device consisting of a mixed cellulose ester paper featuring a wax-encircled, AuNP-coated film atop a cotton absorbent layer sandwiched between two plastic cover layers. In the absence of NADH, the Au3+-CTAB complex dissolves the AuNP layer completely, generating a white color in the test zone. In the presence of NADH, Au3+ is rapidly reduced to Au+, greatly decreasing the dissolution of AuNPs and yielding a red color that becomes stronger at increasing concentrations of NADH. This device exploits capillary force-assisted vertical diffusion, allowing us to apply a 25 μL sample to a surface-confined test zone to achieve a detection limit of 12.5 μM NADH. We used the enzyme glucose dehydrogenase as a model to demonstrate that our paper-based device can monitor NAD+-driven biochemical processes with and without selective dehydrogenase inhibitors by naked-eye observation within 4 min at room temperature in a small sample volume. We believe that our paper-based device could offer a valuable and low-cost analytical tool for monitoring NAD+-associated enzymatic reactions and screening for dehydrogenase inhibitors in a variety of testing contexts.
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, 11200 SW Eighth Street, Miami, Florida 33199, United States.
authors.forename: Pingping
authors.initials: P
authors.lastname: Liang
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, 11200 SW Eighth Street, Miami, Florida 33199, United States.
authors.forename: Haixiang
authors.initials: H
authors.lastname: Yu
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, 11200 SW Eighth Street, Miami, Florida 33199, United States.
authors.forename: Bhargav
authors.initials: B
authors.lastname: Guntupalli
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, 11200 SW Eighth Street, Miami, Florida 33199, United States.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xiao
mesh_terms: D003124:Colorimetry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009243:NAD / Q000032:analysis* / Q000737:chemistry; D010209:Paper; D011934:Reagent Strips; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D011934:Reagent Strips; D009243:NAD; D006046:Gold
keywords: NAD+-driven enzymatic reactions; colorimetric screening; dehydrogenase inhibitors; dihydronicotinamide adenine dinucleotide; dissolution of gold nanoparticles; paper-based device