NaYF₄:Yb,Er Upconversion Nanotransducer with in Situ Fabrication of Ag₂S for Near-Infrared Light Responsive Photoelectrochemical Biosensor

Abstract

An innovative near-infrared (NIR) light-driven photoelectrochemical (PEC) aptasensor was constructed for sensitive screening of carcinoembryonic antigen (CEA) on the basis of in situ formation of AgS nanoparticles on the NaYF:Yb,Er upconversion nanoparticles (UCNs), coupled with hybridization chain reaction (HCR) for the signal amplification. Utilization of UCN as the light nanotransducer could convert the NIR light into an applicable wavelength harvested by semiconductors. The multiemissions of NaYF:Yb,Er UCN could match well with the absorption characteristics of AgS. In the presence of target CEA, a sandwich-type reaction was carried out between capture CEA aptamer/NaYF:Yb,Er-modified electrode and trigger CEA aptamer, which underwent an unbiased strand-displacement reaction to open C-rich hairpin probes in sequence between two alternating hairpins with the assistance of C-Ag-C chelation reaction. Upon addition of sulfide, the chelated Ag ions in the long-nicked DNA poly strands by hybridization chain reaction reacted with sulfide to generate AgS nanoparticles. The formed AgS could utilize effectively the upconversion emissions to amplify the photocurrent. Under optimal conditions, NaYF:Yb,Er-based NIR light-responsive PEC aptasensing platform exhibited high sensitivity for the determination of CEA within a dynamic linear range of 0.005-5.0 ng mL. The limit of detection was 1.9 pg mL. Good precision and high specificity could be acquired in this system for the analysis of target CEA. Human serum samples containing target CEA were measured using our strategy and received well-matched results relative to human CEA enzyme-linked immunosorbent assay kits. Importantly, the NaYF:Yb,Er-based NIR light-responsive PEC aptasensing system provides a new ideal for the detection of disease-related biomarkers using a nucleic acid-based amplification strategy.

Exfoliation and Sensitization of 2D Carbon Nitride for Photoelectrochemical Biosensing under Red Light

“…As metallophthalocyanines have been widely used for in vivo applications such as photodynamic therapy, we envision that further investigation by using a similar principle would make the CNNS–metallophthalocyanine system suitable for NIR. In addition, owing to the lack of suitable photoactive materials, very few works regarding PEC biosensing with red light have been reported, such as using TiO 2 /CdTe/NaYF 4 :Yb/Er, ZnO nanorods/naphthalocyanine, TiO 2 nanotube photonic crystals, Ag NPs/Ag 2 S QDs, and Ag 2 S/NaYF 4 :Yb/Er . This work offers another rare successful example of using metal‐free CN with advantages of highly efficient photoelectron conversion, tailorable molecular, geometric, and electronic structures, low cost, and biocompatibility.…”

“…In addition, owing to the lack of suitable photoactive materials,v ery few works regarding PEC biosensing with red light have been reported, such as using TiO 2 /CdTe/NaYF 4 :Yb/Er,Z nO nanorods/naphthalocyanine, TiO 2 nanotube photonic crystals, Ag NPs/Ag 2 SQ Ds, and Ag 2 S/ NaYF 4 :Yb/Er. [10][11][12][13][14] This work offers another rare successful ex-ample of using metal-free CN with advantages of highly efficient photoelectron conversion,t ailorable molecular,g eometric, and electronic structures,l ow cost, and biocompatibility. Besides, several methods are available for exfoliationo fC N nanosheets, including post-thermal oxidation etching, ultrasonication-assisted liquid exfoliation, and intercalation.…”

“…Among them, metallophthalocyanines (MPcs), which contain alternating C=C and C=N bonds, lead to excellent harvesting of red and near‐infrared light of the solar spectrum for wide applications, for example, organic solar cells, photodynamic cancer therapy, heat absorbers, gas sensors, and bioimaging . Given the unique characteristic of MPcs, coupling of molecular MPc antennas on semiconducting CN by π–π stacking interaction is a reasonable solution to address the above difficulties; however, sensitized CN responsive to long‐wavelength light for PEC biosensing has not been explored, and only very limited work regarding successful PEC biosensing under long‐wavelength light has been reported so far …”

“…[5] However,l ike most other photoactive materials forP EC biosensing, [6][7][8][9] pristine CN only responds to UV and very limited visible light of wavelength shorter than 460 nm. [2] This limits its application in biosensing, because short-wavelength light readily generatesreactive oxygen-containing species, which cause DNA mutation, protein denaturation, and cell damage, [10][11][12][13][14] and also cannot pass through tissue, so that future in vivo applications are challenging.…”

“…[18] Given the unique characteristic of MPcs, coupling of molecular MPc antennas on semicon-ductingC Nb yp-p stacking interaction is ar easonable solution to address the above difficulties; however,s ensitized CN responsive to long-wavelengthl ight for PEC biosensing has not been explored, and only very limited work regarding successful PECb iosensingu nder long-wavelength light has been reported so far. [11][12][13][14] Herein, we report that bulk CN can be facilely exfoliated into nanosheets and noncovalently functionalized with copper phthalocyanine (TsCuPc) for red-lightP EC biosensing. Because of effective photosensitization and donor-acceptor (D-A) interaction, compared with each individual counterpart, the as-prepared CNNS-TsCuPc showedm uch improvedp hotocurrent underr ed-light irradiation, whereby Ts CuPc antennas absorb red light and produce photoelectrons, while CN nanosheets (CNNS) substrates effectively transport the excited charger carriers.…”