Modern healthcare is quite remarkable. You can be tested for a whole range of health conditions within a few short tests. We might not yet have Star Trek medical tricorders, but thanks to major technological advances, rapid diagnostic assays and accurate disease detection is now an everyday reality.
You might imagine these rapid diagnostic tests require complex and sophisticated technologies. However, most new lab-based diagnostic tests harness the humble immunoassay. The concept is straightforward – use antibody-antigen interactions to detect analytes present in a sample.
Although immunoassays have been around for decades, advances in this field are transforming how we treat and monitor diseases from cancer and infectious illnesses to autoimmune disorders. Stay ahead of the game and read on to discover the latest immunodiagnostic trends and technologies that are shaping disease detection.
The diverse spectrum of immunoassays
While every immunodiagnostic test relies on antibody-antigen specificity, a whole range of immunoassay techniques are available. These techniques can be distinguished by their detection method, like colorimetry, fluorescence, or turbidimetry. Let’s take a closer look at some of the most widely employed immunoassays employed today and their pros, cons, and most useful applications:
| Technique | Mechanism | Pros | Cons | Useful applications | |
| Enzyme-linked immunosorbent assays (ELISAs) | Use catalytic enzyme activity to detect antibody-antigen binding via a colorimetric change | Staple technique, popular for its simplicity, sensitivity, and specificity | Nonspecific binding can lead to high background noise. Also, there is a typical turnaround time of 4 to 6 hours | The ability to automate and miniaturize ELISAs makes them well-suited for high-throughput screening (1) | |
| Chemiluminescent immunoassays (CLIAs) | Use luminescent signals to detect analytes | Overcomes some limitations of the traditional ELISA, offering heightened sensitivity | Can be susceptible to interference from other substances present in the sample such as biotin and hemoglobin | Detection of cardiac markers like troponin I and troponin T, which are critical for the diagnosis of myocardial infarction (2) |
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| Fluorescence immunoassays (FIAs) | Use fluorophore-labeled antibodies or antigens for analyte detection | Reduced background interference and high sensitivity. Can simultaneously detect multiple biomarkers from a single sample | Photobleaching effect can occur, where fluorescent dyes degrade upon exposure to light, reducing signal intensity and impacting results | Multiplex FIAs are invaluable in comprehensive screening, such as for drugs of abuse or complex diseases like cancer (3) | |
| Turbidimetric immunoassays | Harness the cloudiness or turbidity in a solution to detect and quantify specific analytes | Quick turnaround times and minimal sample preparation requirements | Low sensitivity, which can be problematic when detecting trace levels of target analyte | Widely applied in measuring proteins, such as C-reactive protein (CRP) for inflammation markers, and albumin levels in liver function tests | |
Improving immunodiagnostics with advanced technology
From microscopic innovations like nanoparticles to big ideas like artificial intelligence (AI), novel technologies are shaping the future of immunodiagnostics. Let's dive into some of these advancements:
Nanotechnology
Nanoparticles are being used to enhance immunoassay performance, offering unique optical and electronic properties. For instance, you could use gold nanoparticles to enhance the visual detection of your test results.
Alternatively, quantum dots could boost the visual detection of your FIA assays and provide stable, sharp fluorescence signals.
Magnetic beads
Magnetic beads, or magbeads, are a unique innovation for immunodiagnostics. These tiny superparamagnetic particles can help you overcome some common challenges in traditional ELISAs and CLIAs.
Magbeads can be used in various ways, such as carriers, support phases, and separation tools. Once coated with specific antibodies or antigens, magbeads bind to target analytes with high specificity. And you can easily isolate bound complexes via their magnetic field (4).
Find the right magnetic bead for your assay
Magbeads provide several benefits in immunoassays: minimal background noise due to less nonspecific binding, plus lower sample and reagent volume needs. These benefits can simplify your assay process and boost diagnostic efficiency and accuracy.
Magbeads can be found with a variety of surface coating and binding properties, suiting a wide range of immunodiagnostic applications. Thanks to their cauliflower-shaped surface, Sera-Mag™ magnetic particles have high binding capacity, allowing for antibody detection even in complex or limited biological samples.
Harness the power of Sera-Mag™ beads for immunoassays
Surface-enhanced Raman spectroscopy (SERS)
SERS is an advanced spectroscopic method that can be integrated into immunoassays. Essentially, SERS uses a technique called Raman scattering to capture the unique chemical composition of a sample. Incorporating SERS into immunoassays has opened new doors for diagnostics, with the ability to detect multiple analytes simultaneously without the need for multiple labels. This approach significantly improves sensitivity and assay robustness.
Microfluidics
Microfluidic chips contain intricate networks of tiny channels and reservoirs to precisely control and manipulate fluids. They look a little like computer chips. These chips are transforming immunoassays, enabling the miniaturization and automation of assay processes. A major advantage of microfluidic immunoassays is the low volume of sample and reagent required, which drastically reduces the time to result (5).
Immunodiagnostics in the digital age
The digital revolution is touching every aspect of healthcare, including diagnostics. The ability to link immunoassays with electronic health records (EHRs), digital imaging, and mobile health apps not only streamlines the entire testing process but also optimizes data management. Digitalizing immunoassays could help us move towards more efficient and integrated healthcare.
AI integration
The emergence of artificial intelligence (AI) could be a significant technological leap for diagnostics, as we’re beginning to see its integration with immunoassays. AI can optimize test performance and accelerate assay turnaround times by interpreting complex data to recognize patterns and predict health outcomes.
Recently, several AI-based microfluidic immunoassays have been developed that are operated using smartphone apps. These sophisticated assays and apps can detect antibody-antigen reactions using phone cameras! They could revolutionize test speed, portability, and accessibility, while also reducing human error (6).
Immunodiagnostic opportunities await
Immunodiagnostics are an increasingly indispensable resource for healthcare providers, providing a means of simple, rapid, and reliable disease detection. The latest innovations, such as nanoparticles, magbeads, SERS, microfluidics, and AI are transforming diagnostic assays faster than ever before. With the promise of enhancing test performance and expanding clinical scope, who knows what the future of immunodiagnostics holds?
- Hayrapetyan H, Tran T, Tellez-Corrales E, Madiraju C. Enzyme-Linked Immunosorbent Assay: Types and Applications. Methods Mol Biol. 2023;2612:1-17. doi:10.1007/978-1-0716-2903-1_1
- Cinquanta L, Fontana DE, Bizzaro N. Chemiluminescent immunoassay technology: what does it change in autoantibody detection?. Auto Immun Highlights. 2017;8(1):9. doi:10.1007/s13317-017-0097-2
- A Chang XH, Zhang J, Wu LH, et al. Research Progress of Near-Infrared Fluorescence Immunoassay. Micromachines. 2019;10(6):422. Published 2019 Jun 24. doi:10.3390/mi10060422
- Xiao Q, Xu C. Research progress on chemiluminescence immunoassay combined with Novel Technologies. Trends in Analytical Chemistry. 2020;124:115780. doi:10.1016/j.trac.2019.115780
- Gao R, Cheng Z, deMello AJ, Choo J. Wash-free magnetic immunoassay of the PSA cancer marker using SERS and droplet microfluidics. Lab Chip. 2016;16(6):1022-1029. doi:10.1039/c5lc01249j
- Huang E, Huang D, Wang Y, et al. Active droplet-array microfluidics-based chemiluminescence immunoassay for point-of-care detection of procalcitonin. Biosens Bioelectron. 2022;195:113684. doi:10.1016/j.bios.2021.113684