Scfv
Overview
BOT Bioscience’s ScFv (Single-Chain Variable Fragment) products are compact, recombinant antibody fragments engineered by linking the variable regions of heavy (VH) and light (VL) chains via a flexible peptide linker (typically 15–25 amino acids). As the smallest functional antibody unit retaining full antigen-binding capability (~27 kDa, 1/5 the size of full-length IgG), ScFv binds to a single epitope of targets (e.g., viral surface proteins, tumor-associated antigens, intracellular signaling molecules) while offering unparalleled spatial flexibility and molecular versatility.
Produced exclusively via recombinant DNA technology (cloning VH-linker-VL sequences into bacterial, yeast, or mammalian expression systems), each ScFv undergoes rigorous validation: specificity testing via ELISA/dot blot (to confirm target binding and eliminate cross-reactivity), affinity measurement via surface plasmon resonance (SPR), and functional verification (e.g., antigen neutralization, receptor blocking). Purified to ≥95% homogeneity (via nickel-chelate or antigen-specific affinity chromatography) and supplied as a stable liquid formulation (in PBS with stabilizers), they are ideal for applications requiring compact size, genetic fusion compatibility, or enhanced tissue penetration.
Applications
Spatial-Restricted Detection: Enable - Imaging antigens in confined biological structures (e.g., synaptic clefts, tight junctions) where full-length antibodies cannot penetrate.
Fusion Protein Engineering: Construction of ScFv-fluorescent protein fusions (e.g., ScFv-GFP) for real-time, live-cell antigen visualization.
Development of ScFv-enzyme conjugates (e.g., ScFv-HRP) for signal amplification in ultra-sensitive diagnostic assays.
Functional Studies: Blocking protein-protein interactions in crowded cellular environments (e.g., disrupting ligand-receptor binding in signaling complexes).
Neutralizing pathogens in spatial constraints (e.g., ScFv targeting bacterial adhesins to prevent biofilm formation).
High-Throughput Screening: Microarray-based antigen profiling (e.g., ScFv arrays for rapid identification of pathogen variants or cancer biomarkers).Phage display library screening to isolate novel antigen-specific ScFv candidates for drug development.
Advantages
Ultra-Compact Size: Small molecular weight enables penetration into dense tissues, biofilms, and intracellular compartments—accessing targets unreachable by full-length antibodies or Fab fragments.
Genetic Versatility: Easily engineered for fusion with other proteins (fluorescent tags, enzymes, toxins) or expression as intracellular antibodies ("intrabodies")—expanding functional applications beyond traditional antibodies.
Reduced Immunogenicity: Minimal non-essential sequences lower immunogenicity compared to full-length antibodies, making them suitable for in vivo studies (e.g., animal model imaging, therapeutic targeting).
Cost-Efficient Production: High-yield expression in bacterial systems (e.g., E. coli) reduces manufacturing costs, ideal for large-scale applications (e.g., industrial diagnostics, high-throughput screening).
Stable Binding: Flexible linker design maintains VH-VL interaction, preserving antigen-binding affinity (nanomolar to picomolar range) while allowing conformational adaptation to target epitopes.
