Melanoma skin cancer is one of the most dangerous skin cancers and the main cause of skin-cancer-related mortality. Hyaluronic acid (HA) has been used as an effective transdermal delivery carrier of chemical drugs and biopharmaceuticals. In this work, a nanographene oxide-HA conjugate (NGO-HA) was synthesized for photothermal ablation therapy of melanoma skin cancer using a near-infrared (NIR) laser. Confocal microscopy and ex vivo bioimaging clearly visualized the remarkable transdermal delivery of NGO-HA to tumor tissues in the skin of mice, which might be ascribed to highly expressed HA receptors and relatively leaky structures around tumor tissues, enabling the enhanced permeation and retention of nanoparticles. The NIR irradiation resulted in complete ablation of tumor tissues with no recurrence of tumorigenesis. The antitumor effect was confirmed by ELISA for caspase-3 activity and histological and immunohistochemical analyses with TUNEL assay for tumor apoptosis. Taken together, we could confirm the feasibility of transdermal NGO-HA for photothermal ablation therapy of melanoma skin cancers.

Gold nanoparticles (AuNPs) have been extensively investigated as an emerging delivery carrier of various biopharmaceuticals. Instead of nonspecific polyethylene glycol (PEG) conjugated interferon α (IFNα) for the clinical treatment of hepatitis C virus (HCV) infection, in this work, a target-specific long-acting delivery system of IFNα was successfully developed using the hybrid materials of AuNP and hyaluronic acid (HA). The HA-AuNP/IFNα complex was prepared by chemical binding of thiolated HA and physical binding of IFNα to AuNP. According to antiproliferation tests in Daudi cells, the HA-AuNP/IFNα complex showed a comparable biological activity to PEG-Intron with a highly enhanced stability in human serum. Even 7 days postinjection, HA-AuNP/IFNα complex was target-specifically delivered and remained in the murine liver tissue, whereas IFNα and PEG-Intron were not detected in the liver. Accordingly, HA-AuNP/IFNα complex significantly enhanced the expression of 2',5'-oligoadenylate synthetase 1 (OAS1) for innate immune responses to viral infection in the liver tissue, which was much higher than those by IFNα, PEG-Intron, and AuNP/IFNα complex. Taken together, the target-specific HA-AuNP/IFNα complex was thought to be successfully applied to the systemic treatment of HCV infection.

SummaryThe emergence and dissemination of extended-spectrum (ES) b -lactamases induce therapeutic failure and a lack of eradication of clinical isolates even by thirdgeneration b -lactam antibiotics like ceftazidime. CMY-10 is a plasmid-encoded class C b -lactamase with a wide spectrum of substrates. Unlike the well-studied class C ES b -lactamase from Enterobacter cloacae GC1, the W -loop does not affect the active site conformation and the catalytic activity of CMY-10. Instead, a three-amino-acid deletion in the R2-loop appears to be responsible for the ES activity of CMY-10. According to the crystal structure solved at 1.55 Å resolution, the deletion significantly widens the R2 active site, which accommodates the R2 side-chains of blactam antibiotics. This observation led us to demonstrate the hydrolysing activity of CMY-10 towards imipenem with a long R2 substituent. The forced mutational analyses of P99 b -lactamase reveal that the introduction of deletion mutations into the R2-loop is able to extend the substrate spectrum of class C non-ES b -lactamases, which is compatible with the isolation of natural class C ES enzymes harbouring deletion mutations in the R2-loop. Consequently, the opening of the R2 active site by the deletion of some residues in the R2-loop can be considered as an operative molecular strategy of class C b -lactamases to extend their substrate spectrum.

Fluorescent nanosized carbon dots (Cdots) are an emerging bioimaging agent with excellent chemical inertness and marginal cytotoxicity in comparison to widely used semiconductor quantum dots. In this work, we report the application of Cdots for real time bioimaging of target specific delivery of hyaluronic acid (HA) derivatives. Polyethylene glycol (PEG) diamine-capped Cdots were synthesized by the pyrolysis of citric acid in a hot solvent. The synthesized Cdots showed strong fluorescence under UV excitation with emission properties dependending on the excitation wavelength. HA-Cdot conjugates were synthesized by amide bond formation between amine groups of Cdot and carboxylic groups of HA. After confirmation of the negligible cytotoxicity of Cdots and HA-Cdot conjugates, in vitro bioimaging was carried out for target specific intracellular delivery of the HA-Cdot conjugates by HA receptor-mediated endocytosis. Furthermore, in vivo real-time bioimaging of Cdots and HA-Cdot conjugates exhibited the target specific delivery of HA-Cdot conjugates to the liver with abundant HA receptors. Taken together, we could confirm the feasibility of HA derivatives as a target-specific drug delivery carrier for the treatment of liver diseases and Cdots as a promising bioimaging agent.

A wearable surface-enhanced Raman scattering (SERS) sensor has been developed as a patch type to utilize as a molecular sweat sensor. Here, the SERS patch sensor is designed to comprise a sweat-absorbing layer, which is an interface to the human skin, an SERS active layer, and a dermal protecting layer that prevents damage and contaminations. A silk fibroin protein film (SFF) is a basement layer that absorbs aqueous solutions and filtrates molecules larger than the nanopores created in the β-sheet matrix of the SFF. On the SFF layer, a plasmonic silver nanowire (AgNW) layer is formed to enhance the Raman signal of the molecules that penetrated through the SERS patch in a label-free method. A transparent dermal protecting layer (DP) allows laser penetration to the AgNW layer enabling Raman measurement through the SERS patch without its detachment from the surface. The molecular detection capability and time-dependent absorption properties of the SERS patch are investigated, and then, the feasibility of its use as a wearable drug detection sweat sensor is demonstrated using 2-fluoro-methamphetamine (2-FMA) on the human cadaver skin. It is believed that the developed SERS patch can be utilized as various flexible and wearable biosensors for healthcare monitoring.

Titanium (Ti) and its alloys with a high mechanical strength and a small diameter can be effectively exploited for minimally invasive dental implantation. Here, we report a multipass caliber-rolled Ti alloy of Ti13Nb13Zr (MPCR-TNZ) with a high mechanical strength and strong fatigue characteristics. For further dental applications, MPCR-TNZ was surface-modified with reduced graphene oxide (RGO) and loaded with osteogenic dexamethasone (Dex) via π-π stacking on the graphitic domain of RGO. The Dex-loaded RGO-MPCR-TNZ (Dex/RGO-MPCR-TNZ) resulted in significantly enhanced growth and differentiation of MC3T3-E1 cells into osteoblasts, which was confirmed by Alizarin red staining, alkaline phosphatase activity test, immunocytochemistry, and real-time PCR. Moreover, we could confirm the feasibility of Dex/RGO-MPCR-TNZ from the implantation test of a prototype of a dental implant to an artificial bone block for clinical dental applications.

Light-absorbing nanoparticles for localized heat generation in tissues have various biomedical applications in diagnostic imaging, surgery, and therapies. Although numerous plasmonic and carbon-based nanoparticles with strong optical absorption have been developed, their clearance, potential cytotoxicity, and long-term safety issues remain unresolved. Here, we show that "generally regarded as safe (GRAS)" melanoidins prepared from glucose and amino acid offer a high light-to-heat conversion efficiency, biocompatibility, biodegradability, nonmutagenicity, and efficient renal clearance, as well as a low cost for synthesis. We exhibit a wide range of biomedical photonic applications of melanoidins, including in vivo photoacoustic mapping of sentinel lymph nodes, photoacoustic tracking of gastrointestinal tracts, photothermal cancer therapy, and photothermal lipolysis. The biodegradation rate and renal clearance of melanoidins are controllable by design. Our results confirm the feasibility of biodegradable melanoidins for various photonic applications to theranostic nanomedicines.

Plasmonic biosensors have demonstrated superior performance in detecting various biomolecules with high sensitivity through simple assays. Scaled-up, reproducible chip production with a high density of hotspots in a large area has been technically challenging, limiting the commercialization and clinical translation of these biosensors. A new fabrication method for 3D plasmonic nanostructures with a high density, large volume of hotspots and therefore inherently improved detection capabilities is developed. Specifically, Au nanoparticle-spiked Au nanopillar arrays are prepared by utilizing enhanced surface diffusion of adsorbed Au atoms on a slippery Au nanopillar arrays through a simple vacuum process. This process enables the direct formation of a high density of spherical Au nanoparticles on the 1 nm-thick dielectric coated Au nanopillar arrays without high-temperature annealing, which results in multiple plasmonic coupling, and thereby large effective volume of hotspots in 3D spaces. The plasmonic nanostructures show signal enhancements over 8.3 × 10 8 -fold for surface-enhanced Raman spectroscopy and over 2.7 × 10 2 -fold for plasmon-enhanced fluorescence. The 3D plasmonic chip is used to detect avian influenza-associated antibodies at 100 times higher sensitivity compared with unstructured Au substrates for plasmon-enhanced fluorescence detection. Such a simple and scalable fabrication of highly sensitive 3D plasmonic nanostructures provides new opportunities to broaden plasmon-enhanced sensing applications.so-called "plasmonic hotspots" are the fundamental basis of numerous promising technologies in the fields of plasmonenhanced spectroscopy, [1][2][3][4][5][6][7][8][9][10] plasmonic biosensing, [11][12][13][14] photocatalysis, [15][16][17][18][19] and nanophotonics. [20,21] One major challenge in expanding the use of plasmonenhanced applications lies in reproducible fabrication of high-density plasmonic hotspots over large areas in a low-cost, highthroughput manner. Various methods have been explored, including aggregations of metallic nanoparticles, nanolithographic patterning, thin-film processing, and hybrid nanostructures. Despite extensive efforts, the development of a reproducible, commercially ready fabrication method that achieves both high quality (i.e., high sensitivity and good reproducibility) and high throughput (i.e., lowcost and wafer-scale fabrication) remains elusive.Among various plasmonic configurations, a nanoparticle-on-mirror (NPOM) geometry, where a nanoparticle is separated from a plain metal film by an ultrathin dielectric spacer layer, has been reported to be a highly efficient plasmonic substrate. [1][2][3][4][5] In the 2D NPOM configuration, however, electromagnetic hotspots are formed around the nanoparticle in a limited area; the effective hotspot volume accounts for a small fraction of the total