Fluorescence-based biosensor platforms have been intensively investigated not only to increase the sensitivity but also to improve the performance of biosensors. By exploiting metal from the macroscopic down to the nanoscopic surface, various architectures have been devised to manipulate fluorescence signals (enhancement, quenching) within near-optical fields. The interaction of a metallic surface with proximal fluorophores (in the range of 5-90 nm) has beneficial effects on optical properties such as an increased quantum yield, improved photostability and a reduced lifetime of fluorophores. This phenomenon called metal-enhanced fluorescence (MEF) has been extensively used in biosensory applications. However, their applications for biological analysis practically remain challenging in biological microenvironments. Therefore, this review primarily provides a general overview of MEF biosensor systems from the basic mechanism to state-of-the-art biological applications. The review also covers the pros and cons of MEF biosensor as well as discussions about further directions in biological perspectives.

Nanoscale silver has been increasingly applied to commercial products for their antimicrobial function as antibiotics and disinfectants. In this work, the different sizes of silver nanoparticles (AgNPs) were studied not only inMethylobacterium spp. for their antimicrobial potential but also in human peripheral blood mononuclear cells (PBMCs) for their cytotoxicity in order to determine responses dependent on their particle size. Size controlled silver particles were prepared by chemical reduction of silver cations (Ag+) and then dispersed in water for their physicochemical characterization using transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential measurements. To ascertain antimicrobial response, water-soluble silver nanoparticles were mixed intoMethylobacterium spp. cultured for two days and the sample from the broth was spread on the agar plate for colony counting. 10 nm nanoparticles showed more antimicrobial activity than 100 nm particles at which concentrations were equivalently controlled. Increased cytotoxic effect of smaller silver nanoparticles was also observed in PBMCs cocultured with particles. Silver ions released from 10 nm particles might be correlated with upregulated antimicrobial and cytotoxic properties of AgNPs.

The extracellular matrix of most natural tissues comprises various types of cells, including fibroblasts, stem cells, and endothelial cells, which communicate with each other directly or indirectly to regulate matrix production and cell functionality. To engineer multicellular interactions in vitro, co-culture systems have achieved tremendous success achieving a more realistic microenvironment of in vivo metabolism than monoculture system in the past several decades. Recently, the fields of tissue engineering and regenerative medicine have primarily focused on three-dimensional co-culture systems using cellular scaffolds, because of their physical and biological relevance to the extracellular matrix of actual tissues. This review discusses several materials and methods to create co-culture systems, including hydrogels, electrospun fibers, microfluidic devices, and patterning for biomimetic co-culture system and their applications for specific tissue regeneration. Consequently, we believe that culture systems with appropriate physical and biochemical properties should be developed, and direct or indirect cell–cell interactions in the remodeled tissue must be considered to obtain an optimal tissue-specific microenvironment.

Recycling is a fascinating topic in academia due to the environmental and economic benefits in industries. In this paper, we report on the method to recycle cellulose waste papers using a green (eco-friendly) approach based on ionic liquids (ILs) where the regenerated cellulose was converted to carbon dots (CDs). The addition of waste papers to the IL, 1-allyl-3-methylimidazolium chloride ([Amim]­[Cl]), disrupted the chemical arrangement of cellulose and completely dissolved the waste paper under microwave irradiation. Subsequent cellulose regeneration by an additional antisolvent, absolute ethanol, was carried out to recover IL and obtain cellulosic materials’ units from waste papers. Furthermore, we report a practical strategy to fabricate CDs under microwave-assisted irradiation. The CDs made by the regenerated cellulose (RC-CDs) were characterized by using analytical and spectroscopic techniques, such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). Finally, we confirmed that RC-CDs exhibited low cytotoxicity, which suggests RC-CDs acts as a promising fluorescent probe for bioimaging.

Biomimetics is the study of nature and natural phenomena to understand the principles of underlying mechanisms, to obtain ideas from nature, and to apply concepts that may benefit science, engineering, and medicine. Examples of biomimetic studies include fluid-drag reduction swimsuits inspired by the structure of shark’s skin, velcro fasteners modeled on burrs, shape of airplanes developed from the look of birds, and stable building structures copied from the backbone of turban shells. In this article, we focus on the current research topics in biomimetics and discuss the potential of biomimetics in science, engineering, and medicine. Our report proposes to become a blueprint for accomplishments that can stem from biomimetics in the next 5 years as well as providing insight into their unseen limitations.

Our results indicated that dehydroglyasperin C may function as a potential anti-photoaging agent by inhibiting UVB-mediated MMPs expression via suppression of MAPK and AP-1 signaling.

Therefore, DGC could be used as a whitening ingredient in skin and clinical usage against hyperpigmentation.

Radioenhancement of gold nanoparticles (GNPs) has shown great potential for increasing the therapeutic efficiency of radiotherapy. Here we report on a computational model of radiation response, which was developed to predict the survival curves of breast cancer cells incubated with GNPs. The amount of GNP uptake was estimated using inductively coupled plasma-mass spectroscopy, and the three-dimensional (3D) intracellular distribution of GNPs was obtained using optical diffraction tomography. The developed computational model utilized the 3D live cell imaging and recent Monte Carlo techniques to calculate microscopic dose distributions within the cell. Clonogenic assays with and without GNPs were performed to estimate the radioenhancement for 150 kVp X rays in terms of cell survival fractions. Measured cell survival fractions were comparable with the computational model.