2 Multi-Technology In Vitro Drug Screening / Validation Kits

In vitro drug screening plays a vital role in drug development for both small molecules and macromolecules. It enables efficient evaluation of potency, selectivity and safety in early-stage development, and generates the pharmacodynamic and mechanistic evidence that guides candidate selection.

ANT BIO offers a tailored solution covering Homogeneous Immuno-Chemiluminescence Assay (HICA), Time-Resolved Fluorescence Resonance Energy Transfer (TR-FRET), OneStep ELISA, bioluminescent assays, ELISpot and flow cytometry (FCM) multiplex assays. Together, these technologies support high-throughput screening and functional assessment across the drug discovery workflow, helping researchers generate reliable data and accelerate therapeutic development.

Technology Pipeline for In Vitro Drug Screening

Each technology occupies a distinct position in the screening pipeline, from target engagement and biomarker quantification to single-cell functional profiling:

1. Biomarker Quantification with OneStep ELISA, HICA and FCM Multiplex Assays

OneStep ELISA: Rapid Biomaker Quantification within 1 Hour 

The OneStep ELISA platform provides rapid biomarker quantification and drug/metabolite detection with a simplified one-hour workflow:

• Simple procedure in one hour: add sample and antibody cocktail, wash and add TMB substrate, then add stop solution and read.
• Excellent sensitivity and dynamic range with good recovery.
• Recombinant antibodies allow tight lot-to-lot variation.
• Custom bulk size available.

Figure 1. OneStep ELISA workflow: add sample and antibody cocktail (45 min), wash and add TMB substrate (10 min), add stop solution and read — the entire assay is completed within 1 hour.

The portfolio spans cytokines, immunoglobulins and complement, hormones and growth factors, disease biomarkers, residue detection, tag purification and other targets across human, monkey, mouse, rat and rabbit samples. The human IFN-γ line illustrates how the platform adapts to different screening scenarios, from routine quantification to ultra-high-sensitivity detection:

HICA: Wash-Free Homogeneous Immuno-Chemiluminescence

HICA abandons the cumbersome washing steps of traditional ELISA, bringing homogeneous detection to high-throughput primary and secondary screening:

• Homogeneous and wash-free: no plate washing required, simplifying the process.
• High sensitivity: detection limits as low as the pg/mL level for trace targets.
• Wide linear range: dynamic range spans 3–4 orders of magnitude, reducing dilution and retesting.
• High throughput: supports automated operation and improves detection efficiency.

Figure 2. HICA principle: excitation of the streptavidin-coated donor bead at 680 nm generates singlet oxygen (¹O₂) that triggers emission of the anti-tag-conjugated acceptor bead at 615 nm upon target-mediated proximity.

FCM Multiplex Assay: Multiple Biomarkers from a Single Sample

The FCM multiplex bead assay quantifies multiple biomarkers simultaneously, adding high-dimensional immune profiling to the screening pipeline:

• High-throughput parallel detection: multiple target analytes measured in a single well; one-run experiment equals dozens of traditional ELISA tests in efficiency.
• Low-sample-volume friendly: requires only 25–50 μL of sample (serum, plasma, cell supernatant, etc.).
• High sensitivity and precision: limit of detection as low as 0.1 pg/mL; intra- and inter-assay CV < 5%; data stability comparable to single-plex ELISA.
• Flexible customization: free-combination target panel options are supported.

2. Binding and Molecular Interaction with TR-FRET

TR-FRET: Molecular Interaction, Enzyme Activity and PROTAC Complexes

The UniOne® TR-FRET platform resolves molecular interactions, enzyme activity and PROTAC ternary complex formation with a no-wash mix-and-measure workflow:

• Specific and sensitive labeling: lanthanide chelates enable precise antibody labeling; antigen proximity drives unique FRET signals for high specificity.
• High signal-to-background ratio: long-lifetime lanthanide chelates with delayed measurement eliminate background, achieving near-zero noise.
• Compatible and high-throughput: no-wash mix-and-measure workflow; signal proportional to chelate concentration; automated high-density plate operation with a wide dynamic range and stable multiplex performance.

Figure 3. TR-FRET principle: Eu-Ab1 is excited at 340 nm and emits at 620 nm; FRET to Ac-Ab2 yields the 665 nm signal only when the two antibodies are brought into proximity by the target complex.

3. Functional and Cellular Profiling with Bioluminescent and ELISpot Assays

Bioluminescent Assay for Cellular Analysis

Built on the luciferase–luciferin–ATP reaction, the UA-Glo® series converts cellular state into a quantifiable luminescent readout, supporting cell viability/toxicity, kinase activity, reporter gene and NanoBRET-based protein detection.

Figure 4. Bioluminescent detection principle: luciferase, luciferin and ATP combine to generate bioluminescent light.

StepSlim ELISpot: Instant Spot Detection at the Single-Cell Level

Based on high-sensitivity antibodies and a mature ELISpot platform, the StepSlim series delivers ready-to-use solutions for single-cell functional immune detection, capturing antigens secreted by cells as visible spots on the PVDF membrane:

• Extreme sensitivity, authentic results: high-sensitivity paired antibodies for efficient capture and detection; free of avidin and endogenous biotin interference.
• Ultra-fast workflow, doubled efficiency: enzyme-direct labeled antibodies save 1 hour of incubation; ready-to-use pre-coated plates can be used directly out of the box, saving a full day.
• Flexible customization: ready-to-use ALP substrate with no on-site preparation required; HRP series for high catalytic efficiency; detachable or fixed plate formats.
• Stable and reliable outcomes: comprehensive validation of data linearity, precision and competitor comparison analysis.

Figure 5. StepSlim ELISpot principle and workflow: capture antigens on the PVDF membrane in a sterile environment (Day 1), then add enzyme-labeled detection antibody and substrate for spot formation (Day 2).

ANT BIO PTE. LTD. – Empowering Scientific Breakthroughs

ANT BIO PTE. LTD. supplies high-quality reagents and solutions for life science research. Our sub-brands cover the full research workflow: Starter for antibodies and immunological assay kits, UA-Bio for recombinant proteins and drug discovery solutions, and Absin for general reagents and other detection kits. Explore our product portfolio at www.antbioinc.com.