Digital Imaging-based Colourimetry for Enzymatic Processes in Transparent Liquid Marbles.

Area of Science:

• Chemistry
• Biochemistry
• Materials Science

Background:

• Liquid marbles offer a versatile microreactor platform for diverse chemical reactions.
• Current reaction monitoring methods for liquid marbles are often destructive and ex-situ, limiting their utility.
• There is a need for non-destructive, in-situ monitoring techniques to fully leverage liquid-marble microreactors.

Purpose of the Study:

• To propose and validate a non-destructive, in-situ, and cost-effective digital-imaging-based colorimetric method for monitoring reactions within transparent liquid marbles.
• To demonstrate the application of this method using the enzymatic hydrolysis of starch as a model system.
• To assess the accuracy and kinetic applicability of the developed monitoring technique.

Main Methods:

• Development of a digital imaging system for capturing colorimetric changes in liquid marbles.
• Utilizing the starch-iodine reaction, which produces a distinct dark blue color, to quantify starch concentration.
• Analyzing the red channel absorbance from digital images to establish a relationship with starch concentration.
• Applying the method to study the kinetics of starch hydrolysis by α-amylase.

Main Results:

• A linear relationship was observed between the red channel absorbance of digital images and starch concentration, demonstrating high sensitivity and repeatability.
• The digital-imaging colorimetric method accurately monitored the enzymatic hydrolysis of starch.
• First-order kinetics were found to be applicable to the starch hydrolysis reaction under the studied conditions.

Conclusions:

• The proposed digital-imaging-based colorimetric method provides a non-destructive, in-situ, and cost-effective means for monitoring reactions in liquid marbles.
• This technique enhances the capabilities of liquid-marble microreactors for various applications.
• The study validates the potential of digital imaging for real-time analysis in microfluidic systems.