Simultaneous competitive and sandwich formats multiplexed immunoassays based on ICP-MS detection

Immunoassays based on inductively coupled plasma mass spectrometry detection: So far so good, so what?

“…DTPA, DOTA, MeCAT®, etc.) and a reactive group which binds covalently to functional groups present in the antibody [24,25,[33][34][35][36][37][38][39][40][41][42][43][44][45][46][47]. As regards transition metals, they have mostly been used as NPs [30][31][32]34,.…”

“…and a reactive group which binds covalently to functional groups present in the antibody [24,25,[33][34][35][36][37][38][39][40][41][42][43][44][45][46][47]. As regards transition metals, they have mostly been used as NPs [30][31][32]34,. Some non-metals (P [48] and I [49]) have been employed as element tags in some applications.…”

“…A large variety of NPs have been proposed (AgNPs [52][53][54][55], PtNPs [53,56], PbSNPs [57], metal/dye-doped silica NPs [58], Cs-doped magnetic NPs [58,59], UCNPs [30,31], EuPO 4 /LuPO 4 NPs [32], Quantum Dots (QDs) [60][61][62][63][64][65], etc.) but AuNPs [34,[53][54][55]63,[66][67][68][69][70][71][72][73][74][75][76] are usually preferred due to their lower cost and greater commercial availability. When compared to REE-based chelates, the use of inorganic NPs affords some attractive and unique features.…”

“…cytokeratin fragment antigen 21-1, carcinoembryonic antigen (CEA) and carbohydrate antigen (CA15-3)) operating a competitive sandwich immunoassay with antibody-coated magnetic beads and detection antibodies conjugated with AuNPs, AgNPs and ZnSeQDs. From our point of view, the lack of multiplexed applications could be attributed to different factors compromising practical analysis such as: (i) NPs limited stability and aggregation phenomena [78]; (ii) signal-tobackground deterioration by non-specific adsorption [34,60,61]; (iii) limited precision due to NP size heterogeneity [63,70]; and (iv) the absence of robust protocols for a reproducible conjugation of antibodies with NPs of different composition/characteristics. Nevertheless, recent works have demonstrated that the above-mentioned shortcomings can be mitigated.…”

Evaluation of an Element-Tagged Duplex Immunoassay Coupled with Inductively Coupled Plasma Mass Spectrometry Detection: A Further Study for the Application of the New Assay in Clinical Laboratory

“…In this technique, multiple rare earth elements (REEs) or their stable isotopes were labeled on the antibodies, distinguished by the mass/charge ratio of the elements. Following the first report of the ICP-MS-based immunoassay for the detection of thyroid hormones in 2001 [19,20], a variety of assays were reported for the quantification of medical markers including duplex labels, multiple labels, and even more than 40 labels [20][21][22][23][24][25][26][27][28][29][30]. Advantages of the ICP-MS-based immunoassay include high sensitivity, high stability, high-level multiplex analysis, low matrix effects, and wide dynamic ranges [30].…”