In the last decade, magnetic nanoparticles (MNPs), especially superparamagnetic iron oxide nanoparticles (SPIONs), have immensely promoted the advancement of diagnostics and theranostics in the biomedical field. The unique properties of the SPIONs-core and the functional gold (Au)-shell together (SPIONS/Au core/shell or CS) have a wide range of biomedical applications including, but not limited to, magnetic resonance imaging (MRI), dual modality MRI/computed tomography (CT), photo-induced and magnetic fluid hyperthermia (MFH), drug delivery, biosensors, and bio-separation. Researchers have made much effort to develop synthesis strategies for size control and surface modifications to achieve the desired properties of these CSs for applications in in vitro and in vivo studies. This review highlights recent developments in the synthesis and biomedical applications of SPIONs/Au CSs, including γ-Fe₂O₃/Au (maghemite), Fe₃O₄/Au (magnetite), and MFe₂O₄/Au (M = divalent metal ions) in the past seven years. More importantly, current trends of SPIONs/Au in relation to the biochemical industry are surveyed. Finally, we outline the developmental needs of SPIONs/Au from the perspective of material synthesis and their novel applications in disease diagnosis and treatment in the near future.

In this study well defined silver nanoparticles were synthesized by using carambola fruit extract. After exposing the silver ions to the fruit extract, the rapid reduction of silver ions led to the formation of stable AgNPs in solution due to the reducing and stabilizing properties of carambola fruit juice. The synthesized NPs were analyzed by ultraviolet-visible spectroscopy and x-ray diffraction pattern. The as-synthesized AgNPs were phase pure and well crystalline with a face-centered cubic structure. The AgNPs were characterized by TEM to determine their size and morphology. The antimicrobial activity of the synthesized AgNPs was investigated against Escherichia coli and Pseudomonas aeruginosa by agar well diffusion method. This newly developed method is eco-friendly and could prove a better substitute for the current physical and chemical methods for the synthesis of AgNPs.

Graphene and graphene-based hybrid materials have emerged as an outstanding supercapacitor electrode material primarily because of their excellent surface area, high electrical conductivity, and improved thermal, mechanical, electrochemical cycling stabilities. Graphene alone exhibits electric double layer capacitance (EDLC) with low energy density and high power density. The use of aerogels in a supercapacitor is a pragmatic approach due to its extraordinary properties like ultra-lightweight, high porosity and specific surface area. The aerogels encompass a high volume of pores which leads to easy soak by the electrolyte and fast charge-discharge process. Graphene aerogels assembled into three-dimensional (3D) architecture prevent there stacking of graphene sheets and maintain the high surface area and hence excellent cycling stability and rate capacitance. However, the energy density of graphene aerogels is limited due to EDLC type of charge storage mechanism. Consequently, 3D graphene aerogel coupled with pseudocapacitive materials such as transition metal oxides, metal hydroxides, conducting polymers, nitrides, chalcogenides show an efficient energy density and power density performance due to the presence of both types of charge storage mechanisms. This laconic review focuses on the design and development of graphene-based aerogel in the field of the supercapacitor. This review is an erudite article about methods, technology and electrochemical properties of graphene aerogel.