What are Peptide Screening Services? These are specialized contract research services offered by biotech companies and CROs (Contract Research Organizations) to discover, optimize, or validate peptide-based molecules for various applications. They provide the expertise, libraries, and high-throughput technologies to efficiently identify peptide hits from vast molecular collections. Core Types of Peptide Screening Services 1. Library-Based Screening This is the most common starting point for discovery. Synthetic Peptide Libraries: Collections of thousands to millions of chemically synthesized peptides. Positional Scanning Libraries: For epitope mapping or identifying key amino acid residues. Truncation & Alanine Scanning: To find the minimal active sequence and critical residues. Phage Display Libraries: The largest and most diverse format (up to 10^11 unique sequences). A library of bacteriophages, each displaying a unique peptide on its coat protein, is panned against a target (e.g., a protein, cell). mRNA/Ribosome Display Libraries: Cell-free systems that link the peptide to its encoding mRNA, allowing for even larger libraries and easier mutagenesis. 2. Functional & Application-Specific Screening Services are tailored to the desired peptide function: Target-Based Screening: Against purified proteins (e.g., enzymes, receptors, GPCRs, protein-protein interaction interfaces). Cell-Based Screening: For peptides that modulate cell signaling, internalize into cells (CPPs), or have antimicrobial (AMP) or anticancer activity. Antigen/Antibody Screening: For epitope mapping, vaccine development,…
Think of it as a sophisticated, high-throughput search and test process. Instead of you building and running every experiment in your own lab, you outsource the initial heavy lifting to experts with specialized libraries and automated systems. Here’s a detailed breakdown: Core Concept The goal is to sift through vast collections (libraries) of peptides—short chains of amino acids—to find the few that bind to a specific target (like a protein, receptor, or cell), catalyze a reaction, or exhibit a desired function (e.g., antimicrobial activity). Key Components of Peptide Screening Services Peptide Libraries: Synthetic Libraries: Collections of thousands to millions of chemically synthesized peptides. They can be diverse (random sequences) or focused (based on a known protein family or structure). Phage Display / Yeast Display Libraries: Genetic libraries where each peptide is displayed on the surface of a virus (phage) or yeast cell, with its DNA sequence inside. This allows for easy amplification and sequencing of "hits." Screening Assays (The "How"): Binding Screens: The most common. Immobilize your target and see which peptides from the library stick to it. Techniques include ELISA, surface plasmon resonance (SPR), and biopanning (for phage display). Functional Screens: Test for a biological effect, like enzyme inhibition, antimicrobial killing, or cell penetration. High-Throughput Screening (HTS): Automated…
“CATALOG APTAMERS & REAGENTS” usually refers to ready-to-order, pre-characterized aptamer affinity binders and the supporting assay reagents that make those binders usable in real experiments (e.g., labeling, immobilization, buffers, and controls). Aptamers themselves are short, single-stranded DNA or RNA (or related chemistries) selected from very large libraries to bind a specific target with high affinity and specificity—often described as antibody-like binding, but built from nucleic acids and produced by chemical synthesis. 1) What Are Aptamers (and Why They Matter as Reagents)? Aptamers are single-stranded nucleic acids that fold into 3D structures capable of recognizing targets such as proteins, small molecules, ions, or even cells. They are typically discovered through SELEX (Systematic Evolution of Ligands by EXponential enrichment), an iterative selection process that enriches sequences that bind the desired target. What makes aptamers especially “catalog-friendly” is that once a sequence is known, it can be reliably reproduced by chemical synthesis, and easily chemically modified (for example, adding a fluorophore or biotin) to fit common assay formats. 2) “Catalog Aptamers” vs Custom Aptamer Discovery Catalog Aptamers (ready-to-order) Catalog aptamers are fixed, known sequences that have been previously selected and are sold as standard products. Their main value…
What “Affinity Determination” Means Affinity determination is the process of quantifying how strongly two molecules bind to each other—commonly protein–protein, antibody–antigen, receptor–ligand, or protein–small molecule interactions. In most bioscience and drug discovery contexts, affinity is summarized by the equilibrium dissociation constant (KD): Lower KD = higher affinity (tighter binding). KD is an equilibrium quantity, meaning it reflects the balance between binding and unbinding at steady state. A related way to express the same concept is the association constant (KA), where KA = 1 / KD. The Core Parameters: KD, KA, kon, koff Affinity can be described in two complementary ways: 1) Equilibrium view (how much binds at steady state) KD (M): concentration at which half of binding sites are occupied in a simple 1:1 interaction model. KA (M⁻¹): binding strength as an association constant (inverse of KD). 2) Kinetic view (how fast binding happens) Many instruments determine affinity by measuring rates: kon (M⁻¹·s⁻¹): association/on-rate (how quickly complex forms) koff (s⁻¹): dissociation/off-rate (how quickly complex falls apart) For a 1:1 interaction: KD = koff / kon (at equilibrium). Surface-based biosensors often estimate affinity by extracting these rates from real-time binding curves. Why Affinity Determination…
CUSTOM APTAMER DISCOVERY & DEVELOPMENT is the process of creating target-specific single-stranded DNA or RNA aptamers—short nucleic acids that fold into 3D shapes capable of binding proteins, small molecules, cells, vesicles, or other targets with antibody-like selectivity. Most custom programs rely on SELEX (Systematic Evolution of Ligands by EXponential enrichment), then refine “hits” into robust, application-ready binders through sequencing-driven analysis and post-selection optimization. 1) What Aptamers Are (and Why They’re Used) Aptamers are typically ~15–90 nucleotides long and can be engineered to bind targets across a wide size range (from small molecules to whole cells). They’re attractive because they are chemically synthesized (batch-to-batch consistency), can be readily labeled (fluorophores, biotin, etc.), and are generally thermally stable and re-foldable—features that often simplify assay development and manufacturing. Common aptamer use cases Diagnostics & biosensors (capture probes, signal transducers, point-of-care formats) Targeted delivery & therapeutics research (cell-directed binding, payload delivery concepts) Affinity purification & analytical workflows (pull-downs, enrichment, separations) 2) The Core Workflow in Custom Aptamer Discovery A custom program is best thought of as a pipeline with four linked decisions: target format → selection strategy → analytics → optimization. Step A — Target Definition and “Bindability” Planning…
“Diagnostics and Therapeutics” is the paired engine of modern healthcare: diagnostics generate actionable evidence about what is happening in the body, and therapeutics use that evidence to choose (and adjust) interventions that improve outcomes. As medicine becomes more data-rich—through molecular testing, advanced imaging, and continuous monitoring—the relationship between diagnostics and therapeutics is shifting from a linear “test-then-treat” workflow to a dynamic feedback loop that refines decisions over time. 1) What “Diagnostics” Means (Beyond Simply Naming a Disease) In clinical practice, diagnostics refers to the tools and methods used to detect, characterize, and track disease-related signals. Importantly, diagnostics is not a single test—it’s a system of evidence that supports decisions across the entire care pathway: Screening diagnostics: detect risk or early disease signals before symptoms are obvious. Diagnostic confirmation: distinguish between conditions with similar presentations. Prognostic diagnostics: estimate likely disease course and severity. Predictive diagnostics: forecast whether a patient is likely to benefit from a specific therapy (a key concept in precision medicine). Monitoring diagnostics: measure response, relapse, or adverse effects over time, enabling treatment adjustment. Major diagnostic categories used today Clinical laboratory diagnostics (blood, urine, tissue, etc.) and medical imaging are foundational, but the fastest-growing…
Aptamers are short, single-stranded nucleic acid molecules (DNA or RNA) that fold into specific 3D shapes and bind targets with high affinity and selectivity—often compared to how antibodies recognize antigens, but built from nucleic acids rather than proteins. Unlike a “generic DNA strand,” an aptamer’s function comes from structure: loops, stems, bulges, pseudoknots, and other motifs that create a binding surface matching a target’s geometry and chemistry. Targets can include proteins, peptides, small molecules, ions, and even whole cells (depending on the selection strategy). Why Aptamers Matter (and How They Differ From Antibodies) Aptamers are often described as “chemical antibodies,” but the differences are exactly why they’re valuable. Key advantages frequently highlighted Low immunogenicity (reduced risk of provoking immune responses) High stability and the ability to refold after denaturation in many cases Easy chemical synthesis (batch consistency, scalable manufacturing) Straightforward modification (labels, linkers, immobilization handles) Trade-offs you should know Nuclease sensitivity (especially RNA aptamers) can be a limitation in biological fluids unless stabilized. Selection bias can occur during discovery (e.g., PCR bias), meaning “best in the tube” isn’t always “best in reality.” Very high affinity does not automatically guarantee best real-world specificity; selection conditions matter. …
Peptide-Drug Conjugates (PDCs) are targeted therapeutics that chemically link a biologically active drug (“payload”) to a peptide that guides the payload toward a specific receptor, microenvironment, or cellular compartment. Conceptually, PDCs resemble Antibody–Drug Conjugates (ADCs), but replace the antibody with a peptide, aiming to keep targeting precision while improving tissue penetration, manufacturing accessibility, and design flexibility. 1) What Exactly Is a PDC (and Why It Matters)? A typical PDC is built from three modular parts: Targeting peptide (the “homing” component) Linker (the chemical bridge that controls stability and payload release) Payload (cytotoxic drug, radionuclide, or other potent therapeutic) This modular architecture allows researchers to tune the PDC for: circulation stability, selective tissue uptake, cellular internalization, controlled release, and overall safety profile. Why it matters: modern drug discovery increasingly values precision delivery—getting more active agent to diseased tissue while reducing exposure to healthy tissue. PDCs are one of the main “next-generation” strategies being explored to push this idea further. 2) PDCs vs ADCs: Same Strategy, Different Vehicle Both PDCs and ADCs aim to deliver potent therapeutics using a targeting moiety + a linker + a payload. The difference is the targeting “vehicle”: ADCs: antibody-based targeting (large proteins)…
Unlock Complex Targets with Our Advanced Toggle SELEX Services At KMD Bioscience, we push the boundaries of aptamer discovery. Traditional SELEX (Systematic Evolution of Ligands by EXponential enrichment) can face challenges with targets that are difficult to immobilize, have low solubility, or require recognition under specific physiological conditions. Our proprietary Toggle SELEX platform provides a powerful, flexible solution to overcome these hurdles and deliver high-affinity, high-specificity aptamers for your most demanding targets. What is Toggle SELEX? Toggle SELEX is an intelligent, counter-selection strategy that evolves aptamers through alternating selection pressures. Instead of selecting solely for binding to your target, the process dynamically toggles between: Positive Selection: Enriching nucleic acid libraries that bind to your primary target. Negative Selection (Counter-Selection): Actively removing sequences that cross-react with closely related molecules, non-target isoforms, or the immobilization matrix itself. This iterative "on/off" selection creates a powerful filtering mechanism, driving the evolution of aptamers with exceptional specificity and minimizing off-target binding. Our Toggle SELEX Advantage: Precision by Design We customize the toggle parameters to fit your exact needs, making it ideal for: Discriminating Between Highly Similar Targets: Isolate aptamers that distinguish between protein family members (e.g., kinase isoforms), mutant vs. wild-type proteins, or phosphorylated vs. non-phosphorylated states. Targeting Membrane Proteins & Complex Antigens: Use cell-based…
Unlock the Potential of Small Molecules with KMD Bioscience’s Precision Aptamer Screening Services In the rapidly evolving landscape of drug discovery, diagnostics, and biomedical research, small molecules remain pivotal targets. However, developing high-affinity, specific molecular recognition tools for these low molecular weight compounds presents a significant challenge. At KMD Bioscience, we bridge this gap with our state-of-the-art Aptamer Screening Services for Small Molecules. We empower researchers and industry partners with precisely engineered nucleic acid aptamers, transforming how small molecules are detected, quantified, and regulated. The Small Molecule Challenge: Why Aptamers? Small molecules (<1000 Daltons) offer limited surface area and epitopes for binding, making traditional antibody generation difficult, time-consuming, and often yielding reagents with cross-reactivity. Aptamers, often termed "chemical antibodies," provide a superior alternative. These single-stranded DNA or RNA oligonucleotides form specific three-dimensional structures that bind to targets with high affinity and selectivity. For small molecules, aptamers offer distinct advantages: High Specificity: Ability to discriminate between structurally similar analogs. Affinity in the Nano- to Micromolar Range: Ideal for detecting and binding small targets. In Vitro Selection (SELEX): Bypasses animals, allowing development against toxins or non-immunogenic molecules. Synthetic Production: Excellent batch-to-batch consistency, ease of modification, and stability. Versatility: Function in diverse matrices (serum, buffers, environmental samples) and formats…
