Label-Free Interaction Monitoring and Analysis

LSPR is a valuable tool to address a broad range of label-free applications in various stages of life science research, drug discovery and development, process development, and manufacturing & QC.

The LightPath™ S4 system can be used for analysis for a wide range of label-free protein-protein interactions.

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LightPath S4 and LSPR biosensors for powerful benchtop label-free analytics


Life Science Research & Drug Discovery

Assay Development

Label-free analysis is uniquely suited to accelerate assay development and move rapidly from concept to optimized assay. Fast and flexible multi-parameter testing happens in real-time and guides efficient selection and optimization of immobilization chemistry and binding conditions while conserving valuable sample.


Assay Development

  • Immunoassays
  • Chemical assays
  • Enzymatic assays

Antibody Characterization

  • Antibody/ligand affinity screening
  • Epitope binning
  • Hybridoma selection and ranking
  • Anti-idiotypic antibody screening
  • Antibody titer
  • Fragment screening

Kinetic Studies

Assay development experiments on how different buffer conditions impact binding activity

Data showing different buffer conditions impacting binding activity during assay development experiments.

Epitope Binning - Sandwich Assay Development

For example, during antibody selection for ELISA development, a simple epitope binning assay was easily applied on LightPath platform to identify non-competing pairs suitable for sandwich assay development. The data shown below is to characterize monoclonal mouse anti-tumor necrosis factor a (TNFα) antibodies for this purpose. All sensor surfaces were modified with TNFα. At ~200 sec, the biosensor surfaces respond to the injections of anti TNFα antibody 1, but not to a generic mouse lgG1 (Green trace), indicating specific binding. After a brief rinse at ~1250 sec, the surfaces were exposed to a second round of analytes. The red sensorgram showed only weak response to a second injection of the mouse anti TNFα antibody 1 because all the binding sites have been occupied by the same antibody injected previously. In contrast, the purple sensorgram showed strong response to the mouse anti TNFα antibody 2. This indicates that two monoclonal anti TNFα antibodies bind simultaneously to a TNFα by recognizing different epitopes and therefore can be used for a sandwich assay.



LSPR technology is particularly useful for kinetic analyses because, upon injection and rinse steps, there is negligible bulk effect which minimizes the need for data manipulations, a potential major source of variance.

Figure below illustrates the LSPR capability to achieve kinetic parameters. The model used here has caboxybenzene sulfonamide on the surface and Bovine Carbonic Anhydrase II, a 29 kDa protein, in solution at concentrations of 100, 33.3, 11.1, 3.33,1.11 µg/ml. A C10 chain is bound to a straptavidin biotin complex that is used to immobilize the biotinylated CBS ligand for CAII binding.

The gray line in the sensorgrams is the response of CAII on a reference surface lacking CBS on the surface. Various repeats show the reproducibility of the responses and yield kinetic information (Kon, Koff and KD), compatible with values reported in the literature using SPR.

Process Development, Manufacturing & QC

Process Development

More effective process development efforts can lead to lower costs at the clinical production scale of therapeutic proteins. However, better technology is needed to effectively and economically develop the process and thereafter be used during manufacturing to monitor the process. Regulatory requirements play a large role in determining how the process will be developed and later implemented. For instance, the concentration of recombinant proteins, that are expressed from cell culture such as CHO cells, must be monitored throughout production using validated assays. The Company’s LSPR technology offers an automated label-free approach to developing assays that are both reproducible and reliable for routine concentration monitoring and analysis. Additionally the same technology can provide kinetic and profiling data to ensure the integrity of the biological that is manufactured during upstream process development (e.g. clonal selection) or downstream processing (e.g. protein capture & elution condition; detection of contaminants and/or undesirable by-products). Collectively, these assays can be used to optimize cell line performance and purification processes.



Manufacturing & QC

LamdaGen’s LSPR is a platform technology particularly well-suited for all stages of the bioprocess arena: including bioprocess development, validation, monitoring and analysis.  Key features of LSPR includes its marginal bulk effect and compatibility with various matrices, including cell media and serum.  Additionally, the Company’s LSPR accommodates both label-free and labeled implementation, with the latter pushing detection limits into the femto- to pico- molar range.  Thus, various approaches using the same core sensor technology allow the detection of biologics in concentrations spanning from trace contaminants to levels of therapeutics antibodies in fermentation.  LSPR also offers advantages in sensitivity, ease of use and throughput compared to methods such as HPLC and ELISA.  Furthermore, LamdaGen’s multi-parallel assays can be performed at-line or in-line using LamdaGen’s automated sampling and PEAK Data Analysis system.

September 2011 – LamdaGen publishes in BioProcess International

BiopharInternational Lamdagen Sept 2010


Concentration Monitoring

Product concentration is likely the most critical parameter to monitor on a routine basis during large-scale manufacturing of recombinant proteins. For instance, determining the best time frame for beginning downstream processing of therapeutic antibodies can influence the success of a manufacturing batch. Knowing when to begin the downstream cycle can limit problems with reduced yields due to premature harvesting or prevent degradation of product which remains too long in the bioreactor. Since ELISA monitoring and analysis is labor intensive and takes many hours for results, a more rapid technique, such as LamdaGen’s label-free LSPR, offers significant advantages in monitoring the process in real-time (product concentration in the bioreactor) and can be implemented on-line or at-line. LSPR can also be used to validate product specifications through characterization assays of biotherapeutic-target binding events and immunogenicity assays to verify safety. Batch differences can easily be identified by monitoring binding interaction profiles for every batch



Concentration Analysis

The use of LSPR detection enables simple and rapid determination of concentrations on a label-free, real time basis, either at-line or on-line, during therapeutic antibody production.

LSPR based method was illustrated here to measure IgG concentrations. The calibration curve shows a wide dynamic range and a lower limit of quantitation of 1 nM human IgG.

Left panel: IgG solutions were injected for 200 s at a flow rate of 120 μl/min.

Right panel: The wavelength shift at 120 s (red line in right panel) was plotted vs. log10 of IgG concentration to generate a calibration curve.

LamdaGen’s  proprietary Peak Data Collection and Analysis Software is the most powerful real-time LSPR analysis software tool available.

Contaminant Monitoring

Routine assays using LSPR in a label-free mode can be implemented to monitor trace levels of contaminants, such as Protein A which has leached into the final product, host cell proteins or contamination by organisms such as mycoplasma. LSPR signals can also be amplified, using labels, to drive detection levels to 100-1000 times more sensitive than ELISA for detection of extremely low level contaminants. This sensitivity enables much earlier intervention during upstream of downstream processing cycles to prevent or reduce product losses.

Click on a subject below for supporting information & data:

Protein A Leaching Detection

  • Ultrasensitive
  • Rapid Detection

Resins containing immobilized Staphylococcal Protein A (PA) are widely used in the commercial purification of recombinant human monoclonal antibody therapeutics. During purification, Protein A can leak from the purification column and contaminate the therapeutic antibody of interest. Since Protein A can cause an immunogenic reaction in patients, a sensitive assay for PA contamination is needed to ensure that PA is not present at unacceptable levels as an impurity in the final therapeutic product.

LamdaGen’s powerful nano-based LSPR platform is ideal for Protein A Leaching detection.

LamdaGen is developing a rapid and highly sensitive (picograms per mg of IgG) test for PA contamination to be used as a QC assay during and following therapeutic antibody production. Different assay formats conducted on the same LSPR surface provide a detection range extending over 6 logs.


Host Cell Protein Assay

LamdaGen’s patented LSPR systems enable highly sensitive and real-time detection of  several manufacturing contaminants.

Residual Host Cell Proteins (HCPs) are biopharmaceutical process-related impurities that may be present downstream in manufacturing as a result of using cell lines, such as mammalian or microbial cells to produce therapeutic proteins. Filtration is used as early as possible in the manufacturing process, and prior to product purification steps, to clear these contaminants. However FDA requires downstream testing to ensure the lack of, or minimal levels, of HCPs in final product. LamdaGen sensor technology is well-suited for multiplexed HCP assays, using either polyclonal or monoclonal antibodies. The Company is developing rapid and specific HCP assays that can offer significant improvements in ease of use and QC reporting.

Mycoplasma Testing

Mycoplasma contamination of eukaryotic cell cultures is very common, ranging from 10-40% in established cell lines based upon recent industry reports. As a result, cultures are treated with antibiotics with possible negative impact on cell lines due to the antibiotics and/or the organism itself. This can include alterations in cell growth, inhibited or stimulated cellular transformations, altered DNA or protein synthesis. Also, since Mycoplasma does not have a cell wall, it is quite flexible in form and can easily pass through virus contamination filters in manufacturing. Therefore FDA requires that Mycoplasma assays be performed on a routine basis in order to ensure the safety of final therapeutic products. Unfortunately, central laboratory tests require days for results to be reported and current near-process tests are cumbersome, can take many hours to complete, and lack sensitivity or the ability to verify that the Mycoplasma detected is actually alive.

LamdaGen is developing with experts in cell culture and microbiological testing to advance its rapid, at-line test for Mycoplasma contamination which incorporates the Company’s leading-edge functional assay detection system made possible through its LSPR sensor platform.

LamdaGen’s patented  LSPR Plasmonic ELISA is ideal for rapid testing of many contaminants including Mycoplasma.