The Hidden Heroes in Medical Devices

Biosensors

Functional films have revolutionized the development of biosensors, providing a platform for highly sensitive and specific detection of biological molecules. For example, thin films of poly(2-hydroxyethyl methacrylate) (pHEMA) are commonly used in biosensing devices due to their biocompatibility and resistance to biofouling. These films can be deposited using plasma-initiated chemical vapor deposition (piCVD) or initiated chemical vapor deposition (iCVD) techniques to create coatings that reduce non-specific protein binding, enhancing sensor accuracy and longevity. In one study, a sodium-sensing optode coated with lightly cross-linked pHEMA films using piCVD demonstrated an eightfold reduction in non-specific protein binding compared to uncoated sensors.

Drug Release Systems

Functional films are also integral to drug delivery systems, enabling controlled release of therapeutic agents. Stimuli-responsive polymer coatings, such as those containing poly(N-isopropylacrylamide) (pNIPAAm) or poly(N,N-dimethyl aminoethyl methacrylate) (pDMAEMA), have been developed to regulate drug release in response to environmental cues like temperature or pH. For example, a membrane coated with pDMAEMA-co-EGDA can regulate the permeability of large molecules like bovine serum albumin (BSA) based on temperature changes, with flux increasing significantly above the lower critical solution temperature (LCST) of the polymer. This technology allows for the design of smart drug delivery systems that can release medication in a controlled manner, improving therapeutic efficacy and reducing side effects.

Tissue Engineering

In tissue engineering, functional films provide scaffolds and coatings that support cell growth and tissue regeneration. Polymers like poly(p-xylylene) (pPX) and its derivatives have been used to create biofunctionalizable coatings for tissue engineering applications. These films can be modified with functional moieties to promote specific interactions with cells and biomolecules, enhancing tissue integration and regeneration. For instance, pPX coatings have been used to fabricate sensor arrays for label-free molecular detection and to boost the sensitivity of fluorescent imaging, demonstrating their versatility in biomedical applications.