Gold nanotheranostics: future emblem of cancer nanomedicine.

Cancer nanotheranostics aims at providing alternative approaches to traditional cancer diagnostics and therapies. In this context, plasmonic nanostructures especially gold nanostructures are intensely explored due to their tunable shape, size and surface plasmon resonance (SPR), better photothermal therapy (PTT) and photodynamic therapy (PDT) ability, effective contrast enhancing ability in Magnetic Resonance imaging (MRI) and Computed Tomography (CT) scan. Despite rapid breakthroughs in gold nanostructures based theranostics of cancer, the translation of gold nanostructures from bench side to human applications is still questionable. The major obstacles that have been facing by nanotheranostics are specific targeting, poor resolution and photoinstability during PTT etc. In this regard, various encouraging studies have been carried out recently to overcome few of these obstacles. Use of gold nanocomposites also overcomes the limitations of gold nanostructure probes and emerged as good nanotheranostic probe. Hence, the present article discusses the advances in gold nanostructures based cancer theranostics and mainly emphasizes on the importance of gold nanocomposites which have been designed to decipher the past questions and limitations of in vivo gold nanotheranostics.

AuPeroxidase nanozymes: Promises and applications in biosensing.

Nanozymes or enzyme mimetic nanostructures possessing intrinsic catalytic activity circumvent various limitations of natural enzymes and hence have emerged as their promising alternative. Gold nanostructures or their hybrids with other metals are popular nanozymes because of their easy synthesis, facile surface modifications, stability, and possessing excellent peroxidase activity. Since 2004, when peroxidase activity was reported for the first time in gold nanoparticles, numerous researches have been done on assessing their peroxidase activity with changing morphology, and making hybrid with different metals. Past few years have witnessed a boom in the use of peroxidase gold nanozyme in biosensing applications. To follow the pace of gold peroxidase (Auperoxidase) nanozyme based biosensing strategies, it is apt to meticulously review this subject. Therefore, the present review covers research publications since 2013 and intends to understand the peroxidase activity in gold nanozymes with variable physico-chemical factors. It further dwells into the proposed mechanisms for the intrinsic peroxidase activity in gold nanozymes. With this review, we intend to present an eagle eye's view of various ways in which gold nanozymes have been used in detection or sensing of diverse analytes such as clinical biomarkers, environmental or food contaminants, antibiotics etc.

Theranostic Nanostructures for Ovarian Cancer.

Ovarian cancer (OC) has emerged as one of the leading causes of death in women due to the lack of early-stage diagnosis resulting in impairment and delay in treatment of malignancy, which raises the morality rate. Existing diagnostic (pelvic examination, CA125, and enzyme-linked immunosorbent assay) or therapeutic modalities (radiotherapy, abdominal pelvic radiation therapy, and chemotherapy) are insufficient to decrease the 5-year survival rate. Nanoparticles (NPs) have been extensively explored as probes for imaging or therapy of cancer. As an extension of this, probes have been designed to possess both imaging and therapeutic modality in a single molecule and this has emerged as the science of nanotheranostics. This review presents the existing diagnostic and therapeutic strategies in use for OC and discusses their loopholes that limit the prognosis of OC. The review presents a general description of important properties of nanostructures and the type of nanostructures that have been used as imaging/therapeutic probe in cancer. The state-of-the-art nanotheranostics probe for targeting OC is presented. Systematic and complete studies that can correlate the findings of researchers from different global areas are lacking. The current status of nanostructures in various phases of clinical trials and those approved by U.S. Food and Drug Administration (FDA) has been presented. No specific targeted theranostic probe for OC has yet been approved by the FDA. Here, the underlying reasons and the challenges faced for nanotheranostics of OC are discussed, along with its future prospects.

Gold nanostructures as cancer theranostic probe: promises and hurdles.

Gold nanostructures (GNSts) have emerged as substitute for conventional contrast agents in imaging techniques and therapeutic probes due to their tunable surface plasmon resonance and optical properties in near-infrared region. Thus GNSts provide platform for the amalgamation of diagnosis and treatment (theranostics) into a single molecule for a more precise treatment. Hence, the article talks about the application of GNSts in imaging techniques and provide a holistic view on differently shaped GNSts in cancer theranostics. However, with promises GNSts also face various hurdles for their use as theranostic probe which are primarily associated with toxicity. Finally, the article attempts to discuss the challenges faced by GNSts and the way ahead that need to be traversed to place them in nanomedicine.