A Molecularly Imprinted Membrane for High-Density Lipoprotein Extraction in Point-of-Care Testing.

Area of Science:

• Biomaterials Science
• Analytical Chemistry
• Point-of-Care Diagnostics

Background:

• Cardiovascular disease risk assessment relies on accurate cholesterol levels, particularly LDL cholesterol.
• Direct point-of-care (POC) quantification of LDL cholesterol requires prior removal of interfering lipoproteins like HDL.
• Molecularly imprinted polymers (MIPs) offer potential for selective molecular recognition and separation.

Purpose of the Study:

• To investigate the efficacy of molecularly imprinted membranes (MIMs) for solid-phase affinity extraction (SPAE) of HDL in a paper-based lateral flow test.
• To assess the feasibility of direct LDL cholesterol quantification after HDL removal.
• To evaluate the integration of SPAE into POC diagnostic platforms.

Main Methods:

• MIMs were fabricated by impregnating membranes with HDL-selective MIPs synthesized via precipitation polymerization.
• Paper-based lateral flow tests were developed, incorporating MIMs for HDL removal prior to enzymatic LDL cholesterol detection.
• The selectivity and uptake capacity of MIPs for HDL were characterized.

Main Results:

• MIPs demonstrated good selectivity for HDL over LDL, with an uptake capacity of 5.0-7.0 µg HDL-C/mg MIP.
• The MIM achieved an average HDL removal efficiency of approximately 68%.
• Significant non-specific binding of LDL was observed, hindering accurate LDL cholesterol quantification, potentially due to LDL's colloidal instability.

Conclusions:

• The study highlights challenges in SPAE of colloidal particles like lipoproteins.
• Despite limitations, the research demonstrates a novel approach for integrating SPAE into paper-based POC diagnostic tests.
• Further optimization is needed to overcome non-specific binding for reliable LDL cholesterol measurement.