Protein Trapping in Plasmonic Nanoslit and Nanoledge Cavities: The Behavior and Sensing

Abstract

A novel plasmonic nanoledge device was presented to explore the geometry-induced trapping of nanoscale biomolecules and examine a generation of surface plasmon resonance (SPR) for plasmonic sensing. To design an optimal plasmonic device, a semianalytical model was implemented for a quantitative analysis of SPR under plane-wave illumination and a finite-difference time-domain (FDTD) simulation was used to study the optical transmission and refractive index (RI) sensitivity. In addition, total internal reflection fluorescence (TIRF) imaging was used to visualize the migration of fluorescently labeled bovine serum albumin (BSA) into the nanoslits; and fluorescence correlation spectroscopy (FCS) was further used to investigate the diffusion of BSA in the nanoslits. Transmission SPR measurements of free prostate specific antigen (f-PSA), which is similar in size to BSA, were performed to validate the trapping of the molecules via specific binding reactions in the nanoledge cavities. The present study may facilitate further development of single nanomolecule detection and new nanomicrofluidic arrays for effective detection of multiple biomarkers in clinical biofluids.

Probing Adsorption Behaviors of BSA onto Chiral Surfaces of Nanoparticles

“…The complete surface coverage was estimated to be ≈58 BSA molecules on Pen–AuNPs, based on the surface area of a sphere with the radius ( R H (0) + Δ R H /2). [18b] The N max values were 61 ± 4 for AuNPs(L) and 60 ± 3 for AuNPs(D). Thus, the BSA molecules sealed the chiral surfaces of Pen–AuNPs with a dense monolayer.…”

“…[17b,36] Here, Pen–AuNPs with BSA corona were considered to be a spherical. So, R H and the number of adsorbed BSA ( N ) could be estimated according to the following equation[18b] R H ( N ) and R H (0) denoted the hydrodynamic radius of Pen–AuNPs with or without BSA corona, N was the number of adsorbed BSA, the coefficient c = V P / V 0 . V 0 was the volume of the bare Pen–AuNPs, and V P was the molecular volume of BSA.…”

“…[13a] Thus, effective methods to investigate the process and mechanism of nanochiral recognition at the protein level are required. A wide range of characterization techniques have been employed to study the interaction between proteins and nanomaterials including dynamic light scattering (DLS), fluorescence correlation spectroscopy, small‐angle X‐ray scattering, transmission electron microscopy (TEM), atomic force microscopy, isothermal titration calorimetry, circular dichroism (CD) spectroscopy, and Fourier transform infrared spectroscopy (FTIR) . These measurement methods allow us to obtain some information about protein adsorption behaviors onto the surface of nanomaterials, including size change, binding strength, thermodynamic, adsorption orientation, and conformational change.…”

A fluorescence-electrochemical study of carbon nanodots (CNDs) in bio- and photoelectronic applications and energy gap investigation

“…After SAM formation, the gold slides were incubated in a 0.5 mM 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, TCI)/ N-hydroxysuccinimide (NHS, Aldrich) for 2 hours to activate the carboxylic acid groups. 26, 27 Next, the gold slides were rinsed with deionized water and immediately moved to a freshly prepared 3 mL solution containing 0.3 mg/mL of CNDs for 2 hours. The gold slides were rinsed with deionized water and dried before experiments.…”

Nanohole array plasmonic biosensors: Emerging point-of-care applications

“…In the first way ( Fig. 6a), a metal layer is deposited prior to the nanopatterning step, and the metallic NHA structures are achieved through subsequent etching of the metal layer using nanopatterned resist as an etch mask (Cetin et al 2015;Cetin et al 2018;Kim et al 2012b;Zeng et al 2017). In the second way ( Fig.…”