11.2 Drug discovery and screening

Optical biosensors are game-changers in drug discovery. They quickly detect how potential drugs interact with targets, speeding up the search for new medicines. These tools can screen thousands of compounds fast, saving time and money in the hunt for effective treatments.

These sensors offer real-time data on how drugs bind to targets, helping scientists understand what makes a good drug candidate. They work without labels, keeping interactions natural, and can catch even tiny changes. This makes them powerful allies in creating better medicines.

Optical Biosensors for Drug Discovery

Role of Optical Biosensors in High-Throughput Screening

Top images from around the web for Role of Optical Biosensors in High-Throughput Screening

• 

  Frontiers | High-throughput drug screening identifies fluoxetine as a potential therapeutic ... View original

  Is this image relevant?

• 

  Frontiers | Application of Machine Learning for Drug–Target Interaction Prediction View original

  Is this image relevant?

• 

  Frontiers | High-throughput drug screening identifies fluoxetine as a potential therapeutic ... View original

  Is this image relevant?

• 

  Frontiers | Application of Machine Learning for Drug–Target Interaction Prediction View original

  Is this image relevant?

1 of 2

Top images from around the web for Role of Optical Biosensors in High-Throughput Screening

• 

  Frontiers | High-throughput drug screening identifies fluoxetine as a potential therapeutic ... View original

  Is this image relevant?

• 

  Frontiers | Application of Machine Learning for Drug–Target Interaction Prediction View original

  Is this image relevant?

• 

  Frontiers | High-throughput drug screening identifies fluoxetine as a potential therapeutic ... View original

  Is this image relevant?

• 

  Frontiers | Application of Machine Learning for Drug–Target Interaction Prediction View original

  Is this image relevant?

1 of 2

• Optical biosensors enable rapid, sensitive, and real-time detection of biomolecular interactions, making them suitable for high-throughput drug screening
• Monitor the binding of drug candidates to target proteins or cells, providing valuable information on drug-target interactions and affinity
• Facilitate the identification of lead compounds from large libraries of potential drug candidates, accelerating the drug discovery process
• Allow for the simultaneous analysis of multiple drug candidates, reducing the time and cost associated with drug discovery
• Offer label-free detection, eliminating the need for fluorescent or radioactive labels, which can interfere with the natural behavior of the drug-target system (preserves native interactions)

Advantages of Optical Biosensors in Drug Discovery

• Provide real-time kinetic data on drug-target interactions, enabling the determination of binding affinity (KD), association rate (kon), and dissociation rate (koff)
• Enable the study of drug-target interactions under various conditions (pH, temperature, buffer composition), providing insights into factors influencing binding
• Allow for competition assays to study the binding of multiple drug candidates to the same target, aiding in the identification of the most promising lead compounds
• Support fragment-based drug discovery (FBDD) by detecting weak interactions between small molecular fragments and target proteins, guiding the design of more potent drug candidates
• Offer high sensitivity and specificity, detecting even subtle changes in biomolecular interactions (nanomolar to picomolar range)

Optical Biosensing Techniques: Comparison

Surface Plasmon Resonance (SPR) and Biolayer Interferometry (BLI)

• SPR biosensors measure changes in refractive index near a metal surface, enabling the detection of biomolecular interactions in real-time
• BLI uses the interference pattern of white light reflected from a biosensor surface to monitor binding events, allowing for high-throughput screening
• Both SPR and BLI are commonly used in drug discovery due to their robustness, sensitivity, and ability to provide kinetic data
• SPR offers a wider range of immobilization strategies (covalent coupling, capture molecules) compared to BLI (mostly streptavidin-biotin)
• BLI allows for higher throughput and faster assay times compared to SPR, making it suitable for screening large compound libraries

Alternative Optical Biosensing Techniques

• Resonant waveguide grating (RWG) biosensors utilize the evanescent field of a waveguide to detect changes in the refractive index caused by biomolecular interactions
• Ellipsometry-based biosensors measure changes in the polarization state of light reflected from a surface, providing information on the thickness and refractive index of the biomolecular layer
• Optical waveguide lightmode spectroscopy (OWLS) uses the evanescent field of a waveguide to monitor the adsorption of biomolecules onto the sensor surface
• RWG, ellipsometry, and OWLS offer unique advantages, such as improved sensitivity (RWG), the ability to probe thin films (ellipsometry), or the capability to measure both adsorbed mass and refractive index (OWLS)
• These alternative techniques can complement SPR and BLI, providing additional information on drug-target interactions and expanding the toolbox for drug discovery

Label-Free Biosensors for Drug-Target Interactions

Studying Binding Affinity and Kinetics

• Label-free optical biosensors enable the study of drug-target interactions without the need for fluorescent or radioactive labels, preserving the native behavior of the biomolecules
• Determine the binding affinity (KD) between a drug candidate and its target protein, which is crucial for assessing the potency and selectivity of the drug
• Derive kinetic parameters, such as association rate (kon) and dissociation rate (koff), from real-time binding data obtained using optical biosensors
• Investigate drug-target interactions under various conditions (pH, temperature, buffer composition), providing insights into the factors influencing binding
• Perform competition assays to study the binding of multiple drug candidates to the same target, aiding in the identification of the most promising lead compounds

Fragment-Based Drug Discovery (FBDD)

• FBDD relies on optical biosensors to detect weak interactions between small molecular fragments and target proteins, guiding the design of more potent drug candidates
• Label-free detection is essential for FBDD, as the small size of fragments makes labeling challenging and may interfere with binding
• Optical biosensors (SPR, BLI) provide the sensitivity required to detect weak fragment-target interactions (millimolar to micromolar range)
• Kinetic data obtained from optical biosensors help prioritize fragments based on their binding affinity and residence time, facilitating the selection of fragments for further optimization
• FBDD using optical biosensors has led to the discovery of several drug candidates (vemurafenib for melanoma, venetoclax for chronic lymphocytic leukemia)

Challenges and Future of Optical Biosensors in Drug Development

Technical Challenges and Solutions

• Robust immobilization strategies are needed to ensure the stability and functionality of the target proteins on the biosensor surface (covalent coupling, capture molecules, oriented immobilization)
• Proper assay development and optimization are crucial to minimize non-specific binding and ensure reliable and reproducible results (buffer optimization, blocking agents, reference subtraction)
• Data analysis and interpretation can be complex, requiring specialized software and expertise to extract meaningful information from the biosensor data (kinetic modeling, global fitting, quality control)
• Integration of optical biosensors with other technologies, such as mass spectrometry or microfluidics, can enhance the throughput and information content of drug screening assays (identification of binding partners, parallel screening)

Future Prospects and Emerging Trends

• Development of portable and cost-effective optical biosensor platforms can expand their application in resource-limited settings and enable decentralized drug testing (point-of-care diagnostics, field testing)
• Advances in surface chemistry and materials science can lead to the development of more sensitive and selective biosensor surfaces, improving the performance of optical biosensors in drug discovery (nanostructured surfaces, stimuli-responsive materials)
• Integration of artificial intelligence and machine learning algorithms can aid in the analysis and interpretation of large datasets generated by high-throughput optical biosensor screening (pattern recognition, predictive modeling)
• Regulatory guidelines and standardization efforts are needed to ensure the quality, reproducibility, and comparability of optical biosensor data in drug development (validation protocols, data reporting standards)
• Expansion of optical biosensor applications beyond small molecule drug discovery, such as the development of biotherapeutics (antibodies, peptides) and the study of membrane protein targets (GPCRs, ion channels)