Surface modification of stainless steel for biomedical applications: Revisiting a century-old material

Stainless steel (SS) has been widely used as a material for fabricating cardiovascular stents/valves, orthopedic prosthesis, and other devices and implants used in biomedicine due to its malleability and resistance to corrosion and fatigue. Despite its good mechanical properties, SS (as other metals) lacks biofunctionality. To be successfully used as a biomaterial, SS must be made resistant to the biological environment by increasing its anti-fouling properties, preventing biofilm formation (passive surface modification), and imparting functionality for eluting a specific drug or capturing selected cells (active surface modification); these features depend on the final application. Various physico-chemical techniques, including plasma vapor deposition, electrochemical treatment, and attachment of different linkers that add functional groups, are used to obtain SS with increased corrosion resistance, improved osseointegration capabilities, added hemocompatibility, and enhanced antibacterial properties. Existing literature on this topic is extensive and has not been covered in an integrated way in previous reviews. This review aims to fill this gap, by surveying the literature on SS surface modification methods, as well as modification routes tailored for specific biomedical applications. STATEMENT OF SIGNIFICANCE: Stainless steel (SS) is widely used in many biomedical applications including bone implants and cardiovascular stents due to its good mechanical properties, biocompatibility and low price. Surface modification allows improving its characteristics without compromising its important bulk properties. SS with improved blood compatibility (blood contacting implants), enhanced ability to resist bacterial infection (long-term devices), better integration with a tissue (bone implants) are examples of successful SS surface modifications. Existing literature on this topic is extensive and has not been covered in an integrated way in previous reviews. This review paper aims to fill this gap, by surveying the literature on SS surface modification methods, as well as to provide guidance for selecting appropriate modification routes tailored for specific biomedical applications.Accepted manuscrip

Multiplexed detection of cancer biomarkers using an optical biosensor

Early detection of cancer is important in administering timely treatment and increasing cancer survival rates. For early cancer detection one can use biomarkers, which are characteristics that can be objectively measured or evaluated as indicators of normal or pathogenic processes. In our study we study three protein biomarkers: carcinoembryonic antigen (CEA), interleukin-6 (IL-6) and extracellular protein kinase A (ECPKA), which have been implicated in various types of human cancer. The main objective of this project is to develop a biosensor for detection of multiple cancer biomarkers. To detect these protein biomarkers high affinity ssDNA aptamers are being selected. Aptamers are short single stranded DNAs with an ability to bind to various targets with high affinity and specificity which selected by SELEX (Systemic Evolution of Ligands through Exponential enrichment) [2]. Ultimately, aptamers against each of the biomarker will be conjugated to magnetic nanoparticles to capture biomarkers from biological fluids. Another aptamer is proposed to be conjugated to quantum dots for quantitation of biomarkers when analyzed on spectrometer

Multiplexed detection of cancer biomarkers using an optical biosensor

Early detection of cancer is important in administering timely treatment and increasing cancer survival rates. For early cancer detection one can use biomarkers, which are characteristics that can be objectively measured or evaluated as indicators of normal or pathogenic processes. In our study we study three protein biomarkers: carcinoembryonic antigen (CEA), interleukin-6 (IL-6) and extracellular protein kinase A (ECPKA), which have been implicated in various types of human cancer. The main objective of this project is to develop a biosensor for detection of multiple cancer biomarkers. To detect these protein biomarkers high affinity ssDNA aptamers are being selected. Aptamers are short single stranded DNAs with an ability to bind to various targets with high affinity and specificity which selected by SELEX (Systemic Evolution of Ligands through Exponential enrichment) [2]. Ultimately, aptamers against each of the biomarker will be conjugated to magnetic nanoparticles to capture biomarkers from biological fluids. Another aptamer is proposed to be conjugated to quantum dots for quantitation of biomarkers when analyzed on spectrometer

Design, synthesis and characterization of self-assembled monodisperse magnetic nanoparticles

Using a co-precipitation method, Fe3O4 nanoparticle surfaces were modified with oleic acid or PEG.This method yields particles with broad size distribution. MNPs synthesized by thermal decomposition method appear to have narrow size distribution and monodispersity

Development of an optical biosensor for diagnosis of tuberculosis

Tuberculosis (TB) is an airborne disease caused by Mycobacterium tuberculosis. TB is the leading cause of morbidity and mortality in the developing world. Early and accurate diagnosis of TB would greatly enhance the treatment and prevention of the disease. Current methods of TB detection suffer from various limitations such as low specificity and sensitivity, being too complex and expensive. In the present work, we aim to develop an optical biosensor based on DNA aptamers, quantum dot (QD) crystals and magnetic nanoparticles (MNP) for detection of MPT64 protein, specific to M.tuberculosis. Aptamer-MNP conjugate is used for separation of MPT64 from solution, while aptamer-QD is used to detect its presence afterwards using fluorometer