Cholesterol oxidase on polystyrene nanoparticles decorated with congo red

Rapid growth in the development of new biomaterials and the improvements in sensing techniques have given boost to the evolution of new biosensors, where the immobilization and stability of enzymes, antibodies and DNA etc. onto solid support are crucial factors for the fabrication of a biosensor, which it can increasing enzyme stability and expanding the application fields.

The estimation of cholesterol on a periodical basis is essential for living beings because the abnormal levels of cholesterol are related to heart diseases. In addition, cholesterol and its fatty acid esters are essential components of nerve cells and are precursors of many biomaterials such as bile acid and steroid hormones.

Here I`m reporting the results of mine studies relating to cholesterol biosensor based on fisical immobilization of cholesterol oxidase (ChOx) onto polystyrene (PS) nanoparticles decorated with Congo red (CR).

Here, Our aims was develop a biosensor device from cholesterol oxidase immobilized onto Congo red decorated onto polymer nanoparticles.

NpPS/PEG was characterized by means of dynamic light scattering (DLS) and zeta (ζ) potential. The adsorption of Congo red (CR) onto PS/PEG particles was evidenced by adsorption isotherms, decrease of ζ potential values and increase in the mean diameter. Cholesterol oxidase (ChOx), the main enzyme in the oxidation of cholesterol, adsorbed onto PS/PEG and PS/PEG/CR particles, as evidenced by the increase in the particles mean size and spectrophotometry. The enzymatic activity of free and immobilized ChOx was determined as a function of time by means of a coupled reaction with horseradish peroxidase.

Figure 1: Particle size (zeta-average diameter, D) and size distribution were determined using the ZetaPlus-ZetaPotential . Scanning electron microscopy (SEM) analyses were performed to determine the morphology and mean diameter of dried particles. Here, both histograms indicate bimodal size distribution with