Metallic Fe–Au Barcode Nanowires as a Simultaneous T Cell Capturing and Cytokine Sensing Platform for Immunoassay at the Single-Cell Level

Abstract

Barcode nanowires (BNWs) composed of multiple layered segments of different materials are attractive to bioengineering field due to their characteristics that allow the adjustment of physicochemical properties and conjugation with two or more types of biomolecules to facilitate multiple tasks. Here, we report a metallic Fe (iron)−Au (gold) BNW-based platform for capturing CD8 T cells and the interferon-γ (γ) they secrete, both of which play key roles in controlling infectious diseases such as tuberculosis, at the single-cell level. We also describe an efficient approach for conjugating distinct antibodies, which recognize different epitopes to appropriate materials. The platform achieved detection even with 4.45−35.6 μg mL −1 of BNWs. The T cell capture efficiency was close to 100% and the detection limit for interferon-γ was 460 pg mL −1 . This work presents a potential guideline for the design of single-cell immunoassay platforms for eliminating diagnostic errors by unambiguously identifying disease-relevant immune mediators.

Projection method as a probe for multiplexing/demultiplexing of magnetically enriched biological tissues

“…The special cylindrical geometry of MNWs gives rise to a well-dened magnetic anisotropy 16 that makes them suitable for many biological applications, such as MRI contrast, magnetic enrichment, and nanowarming. 11,[17][18][19][20][21] An external eld can be remotely used to physically excite MNWs, which makes them suitable for cell tracking, [22][23][24][25] cells manipulation, 26 cell separation, 27,28 drug delivery and drug activation, 29,30 magnetic hyperthermia, 21 and magneto-elastic ferrogels for tissue engineering. 31,32 Furthermore, the MNWs have shown a high internalization by cells in comparison to other magnetic nanoparticles, such as IONs, improving the enrichment and multiplexing yield.…”

A Guideline for Effectively Synthesizing and Characterizing Magnetic Nanoparticles for Advancing Nanobiotechnology: A Review

“…Magnetic nanoparticles are promising enrichment agents compared to optical nanoparticles [2,179]. This is because the magnetically enriched biological entities, such as cells, can be rapidly and cost-effectively separated and isolated from the whole population using a simple magnet [160] ( Figure 20).…”

Unlocking the decoding of unknown magnetic nanobarcode signatures

“…Encoding and decoding techniques are the two main bottlenecks hindering the successful interchange of nanobarcodes within diverse applications [1]. As a result, numerous types of nanobarcodes, such as photonic nanoparticles [2][3][4], magnetic nanoparticles [5][6][7], and magneto-optic nanoparticles [8], have emerged to meet the desired requirements for individual applications. The synthesis approach of nanobarcodes can allow one to engineer multiple properties, such as absorption/emission spectra of photonic nanoparticles [9][10][11], coercivity and saturation magnetization of magnetic nanoparticles [7,[12][13][14][15], to leverage their encoding through various synthesis strategies, both chemical and physical strategies [16][17][18][19], that feasibly tune properties.…”

“…We believe this technological limitation, inability to decode unknown combinations of magnetic nanobarcodes, is due to the magnetic measurements and a lack of a robust analytical approaches for decoding the measured magnetic signature. For example, the hysteresis loop method has been widely used to measure the saturation magnetization (M s ) and coercivity (H c ) as magnetic signatures for decoding the magnetic nanobarcodes [7,12,14,20,21]. Since the hysteresis loop method only provides averaged values for M s and H c , it does not provide any insight for decoding them if there is no prior knowledge about the number and types of magnetic nanobarcodes at the readout.…”