Usually this modification is produced to solid materials, but examples of modifying the surface of particular liquids can also be found.
The modification can be performed using distinct techniques to change a broad variety of surface features such as: roughness, hydrophilicity, surface charge, surface energy, biocompatibility and reactivity .
PEG Applications: Surface Modification
High content screening (HCS) is a useful biological assay study method to identify applicants for drugs. HCS platform miniaturization has considerably decreased processing time and enhanced early drug discovery efficiency. It’s reported that there is a group has recently created a prototype micro-optofluidic cell sensing tool for pathogen sensing with localized dosing control. The instrument consists of glass reservoirs for cell growth and polycarbonate (PC) membrane valves with PDMS microchannels that are electrically stimulated for regulated drug release. However, experimental failure induced by cells adhering to the PDMS channels and PC membrane is of concern. Loss of any sample quantity is critical because it compromises the device's long-term accuracy.
Material adsorption of proteins is an important prerequisite for cell adhesion, supplying nutrients for adherent cell lines and anchorage.This process is mediated by surface hydrophobicity, called biofouling. Implementation of surface modification approaches to further reduce PDMS and PC membrane hydrophobicity may be used to reduce cell adhesion. All frequently used antifouling methods are plasma therapy, UV therapy, metal coating, dynamic surface modification and polyethylene glycol (PEG) grafting. One of the most effective and well-documented techniques for modifying PDMS surfaces is PEG grafting. PEG grafting processes will therefore be used to modify PDMS and PC antifouling surfaces.
The PEG grafting operation is shown in Fig. 1. On PDMS and PC surfaces, a (3-Aminopropyl) triethoxysilane (APTES) layer is created to tie the PEG-DA chains. In this sector, it is advantageous to use APTES and PEG-DA to modify both materials, as most grafting processes are specific to the material for which it was designed for. This technique can also be applied to products linked to silicon. In contrast, glass's hydrophilic nature may decrease cell adhesion. APTES alone is therefore used to boost the biofouling of glass and localize cell growth within the wells.
Fig. 2 Displays a 66% decrease in PDMS-PEG albumin adsorption relative to unmodified PDMS. These preliminary findings demonstrate the success of the PDMS antifouling modification approach. Protein adsorption quantification on altered PC membrane and glass as well as tests on cell adhesion will be carried out in the near future. These changes will then be implemented to a fresh prototype device and long-term stability testing will be carried out.
