Label-free detection of C-Reactive protein using bioresponsive hydrogel-based surface relief diffraction gratings

Area of Science:

• Biomaterials Science
• Optical Sensing Technologies
• Biochemical Analysis

Background:

• Responsive hydrogels with surface relief gratings show promise as optical biosensors.
• Existing hydrogel biosensors have limited specificity for analytes and biomolecules.
• Development of novel hydrogels is crucial for advanced biosensing applications.

Purpose of the Study:

• To develop a novel biosensing system utilizing bioresponsive hydrogels and surface relief gratings.
• To create a hydrogel capable of specifically recognizing and detecting C-Reactive protein (CRP).
• To demonstrate label-free detection of CRP in human serum using a laser-based optical setup.

Main Methods:

• Fabrication of micro-gratings on CRP-sensing hydrogel substrates using Direct Laser Interference Patterning.
• Development of a homemade laser-based optical setup for label-free CRP detection.
• Application of amplification strategies to enhance biosensor sensitivity and performance.

Main Results:

• The CRP-sensing hydrogel selectively detected CRP with limits of detection (LOD) and quantification (LOQ) of 1.07 mg L⁻¹ and 8.92 mg L⁻¹, respectively.
• Amplification strategies improved sensitivity, achieving LOD of 0.30 mg L⁻¹ and LOQ of 4.36 mg L⁻¹.
• The biosensing system demonstrated high accuracy with ~100% recovery in certified human serum samples.

Conclusions:

• The developed biosensing system enables selective, label-free detection of CRP at clinically relevant concentrations.
• The system shows potential for early diagnosis of cardiovascular diseases and sepsis.
• The use of bioresponsive hydrogels and surface relief gratings offers a versatile platform for advanced biosensing.