Evaporation-Induced Biomolecule Detection on Versatile Superhydrophilic Patterned Surfaces: Glucose and DNA Assay

Abstract

We introduce a droplet-based biomolecular detection platform using robust, versatile, and low-cost superhydrophilic patterned superhydrophobic surfaces. Benefitting from confinement and evaporation-induced shrinkage of droplets on wetted patterns, we show enrichment-based biomolecular detection using very low sample volumes. First, we developed a glucose assay using fluorescent polydopamine (PDA) based on enhancement of PDA emission by hydrogen peroxide (H2O2) produced in enzyme-mediated glucose oxidation reaction. Incubation in evaporating droplets resulted in brighter fluorescence compared to that in bulk solutions. Droplet assay was highly sensitive toward increasing glucose concentration while that in milliliter-volume solutions resulted in no fluorescence enhancement at similar time scales. This is due to droplet evaporation that increased the reaction rate by causing enrichment of PDA and glucose/glucose oxidase as well as increased concentration of H2O2 generated in shrinking droplet. Second, we chemically functionalized wetted patterns with single-stranded DNA and developed fluorescence-based DNA detection to demonstrate the adaptability of the patterned surfaces for a different class of assay. We achieved detection of glucose and DNA with concentration down to 130 μM and 200 fM, respectively. Patterned superhydrophobic surfaces with their simple production, sensitive response, and versatility present potential for bioanalysis from low sample volumes.

Tailoring Materials with Specific Wettability in Biomedical Engineering

“…Meanwhile, Beyazkilic et al reported a superwetting platform as glucose biosensor depending on the fluo-rescent PDA (Figure 10g-i). [195] The PDA emission could be enhanced by H 2 O 2 , the product of glucose oxidation reaction, providing a powerful tool for glucose detection. In addition, the enrichment capacity of superhydrophilic patterned superhydrophobic substrate imparted the biosensor with increased reaction rate and sensitivity.…”

“…To solve these, researchers have dedicated to developing biomaterials with specific wettability, together with adding antibacterial ingredients for further treatment. Up to date, medical dressings based on biomaterials with specific wettability have demonstrated values in accelerating the wound healing process through removing excessive biofluid around wounds, [ 96 , 174 ] inhibiting adhesion of harmful biomolecules, [ 174 , 175 , 176 , 177 , 178 , 179 , 180 , 181 , 182 , 183 , 184 , 185 , 186 , 187 , 188 , 189 , 190 , 191 , 192 , 193 , 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 , 202 , 203 , 204 , 205 , 206 , 207 , 208 , 209 , 210 , 211 , 212 , 213 , 214 , 215 , 216 , 217 , 218 , 219 ,…”

“…To solve these, researchers have dedicated to developing biomaterials with specific wettability, together with adding antibacterial ingredients for further treatment. Up to date, medical dressings based on biomaterials with specific wettability have demonstrated values in accelerating the wound healing process through removing excessive biofluid around wounds, [ 96,174 ] inhibiting adhesion of harmful biomolecules, [ 175–179,174,180–234 ] and releasing therapeutic drugs or molecules. [ 175–179,174,180,235–237 ]…”

“…i) Fluorescent images of evaporated droplets containing glucose in fluorescent polydopamine (PDA) spots. g-i) Reproduced with permission [195]. Copyright 2018, American Chemical Society.…”

Micro/Nanopatterned Superhydrophobic Surfaces Fabrication for Biomolecules and Biomaterials Manipulation and Analysis

“…Ren et al, used a PDMS-made SHS treated by CF 4 /O 2 plasma to increase superhydrophobicity as a concentrator of DNA for high-dilution detection [117]. Other authors have obtained an analogous result on DNA or other molecules using a disordered SHS [118,119]. A SEM picture of a pillar realized on silicon is shown in (F), which has a dual-electrode sensor fabricated on its top and contacted for electrical measurements.…”