Bio devices I
Raman spectroscopy has been widely utilized as a powerful tool for biochemical and environmental analyses because of its capability to perform rapid molecular detection and easy operation under ambient conditions. Moreover, Raman signals offer structural and compositional information based on fingerprint spectra of analytes without labels. However, intrinsic Raman signals of analytes are usually weak, and thus various types of metallic nanostructures for surface-enhanced Raman scattering (SERS) have been developed for sensitive and reproducible detection. The aforementioned nanostructures can drastically enhance the electromagnetic fields, as attributed to surface plasmon resonance resulting from the collective oscillation of free electrons at the surface of metals by an external light source. Among them, porous and three-dimensional (3D) plasmonic structures have been introduced as SERS-active substrates due to their structural benefit in trapping the analytes. Moreover, 3D plasmonic structures contain a greater number of hot spots in the probe volume than 2D plasmonic substrates, which is favorable for collecting strong SERS signals. However, common 3D plasmonic structures with porosity encounter difficulties in measuring a uniform SERS signal over a large surface area due to the irregular pore sizes of the templates and uneven generation of electric hotspots around the plasmonic nanostructures. To this end, 3D templates with highly ordered porosity and excellent electric properties would be good candidates for fabricating 3D SERS-active structures.
Bio devices II
The recent outbreak of multidrug-resistant (MDR) bacteria and related infectious diseases as a result of antibiotic abuse has emerged as a global public health problem for many years, and it is essential to develop new antibacterial agents instead of using weakened traditional antibiotics. Accordingly, antibacterial agents using novel approaches such as virulence blockers, antisense oligonucleotides, antibacterial peptides, phage therapy, and metal nanoparticles have been reported to date. Compared with traditional antibiotics, the proposed antibacterial strategies showed effective antibacterial effects against MDR bacteria by avoiding common resistance mechanisms or inhibiting cytotoxicity. However, in the antibacterial strategy of oligonucleotides and peptides, penetration efficiency and stability may be reduced owing to the large size, high anionic charge, and hydrophilic nature of the bacterial membrane. In addition, phage therapy is bacterial-selective, making its use controversial because of the existence of phages that are less desirable for therapeutic use owing to their narrow target range and poor pharmacokinetics.
