Spectroscopic Secondary Structure Analysis Tools For Protein Characterization

RedShiftBio's secondary structure analysis tools include the AQS3pro, which will change how you measure protein and peptide structure. Powered by Microfluidic Modulation Spectroscopy (MMS), it ramps up the sensitivity, dynamic range and accuracy of IR spectroscopy. Designed for five key measurements—protein aggregation, quantitation, stability, similarity, structure—the AQS3pro directly supports protein characterization throughout the biopharmaceutical development pipeline.


Diagram shows the tunable laser in our secondary structure analysis tools, which probes the protein solution through a microfluidic cell. The microfluidic cell fluids rapidly alternate between sample and reference (buffer) streams to continuously and automatically perform background subtraction, dramatically improving measurement precision, accuracy, and signal-to-noise.

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AQS3pro brochure image

The advantages of Microfluidic Modulation Spectroscopy (MMS)

MMS is a novel and efficient technique for label-free protein analysis that directly addresses the limitations of current technologies. MMS provides drift-free, background subtracted, high sensitivity measurements of the protein secondary structure across four decades of concentration—from 0.1 to over 200 mg/mL.


  • Automated multi-sample analysis for walk away operation
  • High sensitivity to see change reproducibly at high precision
  • The widest concentration range to characterize biotherapeutics
  • Analytical software that easily transitions data into insight


Advanced data processing software to leverage increased data quality

The AQS3pro is perfectly paired with AQS3delta software, a suite of analytical tools that within seconds turn high quality data into scientific insight. Concerned about stability? Then track changes between spectra, at individual spectral locations or across structural motifs that you can define. Or analyze similarity with the Area of Overlap tool. Take a look at the data flow analysis below to see one way how the AQS3delta software processes and presents data to maximize the value of each measurement.

See Change in Your Protein Characterization Workflow

Data flow analysis of BSA at 1.0mg/mL

Differential Absorbance Spectra

Continuous, rapid modulation between the sample solution and buffer reference streams produces a differential absorbance signal.

Absolute Absorbance Spectra

Buffer subtraction and concentration normalization enable direct protein-protein structural comparisons.

Second Derivative Spectra

Second derivative spectra accentuate the specific structural differences between protein samples.

Delta of Second Derivative

Delta of second derivative plots highlight structural differences and change in protein samples.


Protein stability can be assessed by tracking changes in secondary structure motifs.


Protein similarity can be compared using area of overlap plots.

Higher Order Structure

Higher order structure analysis quantifies the fractional content of different secondary structure motifs.


Proteins can be quantified over a linear concentration range that extends from 0.01 to > 200 mg/mL.


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