Satellite-like Gold Nanocomposites for Targeted Mass Spectrometry Imaging of Tumor Tissues

The Advancing Role of Nanocomposites in Cancer Diagnosis and Treatment

The relentless pursuit of effective cancer diagnosis and treatment strategies has led to the rapidly expanding field of nanotechnology, with a specific focus on nanocomposites. Nanocomposites, a combination of nanomaterials with diverse properties, have emerged as versatile tools in oncology, offering multifunctional platforms for targeted delivery, imaging, and therapeutic interventions. Nanocomposites exhibit great potential for early detection and accurate imaging in cancer diagnosis. Integrating various imaging modalities, such as magnetic resonance imaging (MRI), computed tomography (CT), and fluorescence imaging, into nanocomposites enables the development of contrast agents with enhanced sensitivity and specificity. Moreover, functionalizing nanocomposites with targeting ligands ensures selective accumulation in tumor tissues, facilitating precise imaging and diagnostic accuracy. On the therapeutic front, nanocomposites have revolutionized cancer treatment by overcoming traditional challenges associated with drug delivery. The controlled release of therapeutic agents from nanocomposite carriers enhances drug bioavailability, reduces systemic toxicity, and improves overall treatment efficacy. Additionally, the integration of stimuli-responsive components within nanocomposites enables site-specific drug release triggered by the unique microenvironment of the tumor. Despite the remarkable progress in the field, challenges such as biocompatibility, scalability, and long-term safety profiles remain. This article provides a comprehensive overview of recent developments, challenges, and prospects, emphasizing the transformative potential of nanocomposites in revolutionizing the landscape of cancer diagnostics and therapeutics. In Conclusion, integrating nanocomposites in cancer diagnosis and treatment heralds a new era for precision medicine.

Detection of Single Ag Nanoparticles Using Laser Desorption/Ionization Mass Spectrometry

The detection of a single entity (molecule, cell, particle, etc.) was always a challenging subject. Here we demonstrate the detection of single Ag nanoparticles (NPs) using subatmospheric pressure laser desorption/ionization mass spectrometry (LDI MS). The sample preparation, measurement conditions, generated ions, and limiting experimental factors are discussed here. We detected from 84 to 95% of the deposited 80 nm Ag NPs. The presented LDI MS platform is an alternative to laser ablation inductively coupled plasma mass spectrometry for imaging distribution of individual NPs across the sample surface and has a great potential for multiplexed mapping of low-abundance biomarkers in tissues.

Current and Future Nano-Carrier-Based Approaches in the Treatment of Alzheimer's Disease

It is a very alarming situation for the globe because 55 million humans are estimated to be affected by Alzheimer's disease (AD) worldwide, and still it is increasing at the rapid speed of 10 million cases per year worldwide. This is an urgent reminder for better research and treatment due to the unavailability of a permanent medication for neurodegenerative disorders like AD. The lack of drugs for neurodegenerative disorder treatment is due to the complexity of the structure of the brain, mainly due to blood-brain barrier, because blood-brain drug molecules must enter the brain compartment. There are several novel and conventional formulation approaches that can be employed for the transportation of drug molecules to the target site in the brain, such as oral, intravenous, gene delivery, surgically implanted intraventricular catheter, nasal and liposomal hydrogels, and repurposing old drugs. A drug's lipophilicity influences metabolic activity in addition to membrane permeability because lipophilic substances have a higher affinity for metabolic enzymes. As a result, the higher a drug's lipophilicity is, the higher its permeability and metabolic clearance. AD is currently incurable, and the medicines available merely cure the symptoms or slow the illness's progression. In the next 20 years, the World Health Organization (WHO) predicts that neurodegenerative illnesses affecting motor function will become the second-leading cause of mortality. The current article provides a brief overview of recent advances in brain drug delivery for AD therapy.

Surface-assisted laser desorption/ionization mass spectrometry imaging: A review

In the last decades, surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) has attracted increasing interest due to its unique capabilities, achievable through the nanostructured substrates used to promote the analyte desorption/ionization. While the most widely recognized asset of SALDI-MS is the untargeted analysis of small molecules, this technique also offers the possibility of targeted approaches. In particular, the implementation of SALDI-MS imaging (SALDI-MSI), which is the focus of this review, opens up new opportunities. After a brief discussion of the nomenclature and the fundamental mechanisms associated with this technique, which are still highly controversial, the analytical strategies to perform SALDI-MSI are extensively discussed. Emphasis is placed on the sample preparation but also on the selection of the nanosubstrate (in terms of chemical composition and morphology) as well as its functionalization possibilities for the selective analysis of specific compounds in targeted approaches. Subsequently, some selected applications of SALDI-MSI in various fields (i.e., biomedical, biological, environmental, and forensic) are presented. The strengths and the remaining limitations of SALDI-MSI are finally summarized in the conclusion and some perspectives of this technique, which has a bright future, are proposed in this section.

Controlling morphology evolution of titanium oxide-gold nanourchin for photocatalytic degradation of dyes and photoinactivation of bacteria in the infected wound

We report a one-pot, room-temperature, morphology-controlled synthesis of titanium oxide (TiO_x)-gold nanocomposites (TiO_x-Au NCs) using HAuCl₄ and TiCl₃ as precursors, and catechin as reducing agent. TiO_x-Au NCs have a range of morphologies from star-like to urchin-like shape depending on the concentration of TiCl₃ in the reaction mixture. The urchin-shaped TiO_x-Au NCs exhibited excellent photocatalytic activity toward dye degradation due to strong light absorption, plasmon-induced excitation, high conductivity of the gold, and reduced hole-electron pair recombination. TiO_x-Au NCs have the advantage of a wide range of light absorption and surface plasmon absorption-mediated excitation due to their abundant gold spikes, which enabled the degradation of dyes over 97% in 60 min, using a xenon lamp as a light source. In addition, TiO_x-Au NCs are highly efficient for the photoinactivation of Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans through the photodynamic generation of reactive oxygen species (ROS) and damage to the bacterial membrane. The catechin derivatives on the NCs effectively promoted curing MRSA infected wounds in rats through inducing collagen synthesis, migration of keratinocytes, and neovascularization.

Aptamers in Drug Design: An Emerging Weapon to Fight a Losing Battle

Implementation of novel and biocompatible polymers in drug design is an emerging and rapidly growing area of research. Even though we have a large number of polymer materials for various applications, the biocompatibility of these materials remains as a herculean task for researchers. Aptamers provide a vital and efficient solution to this problem. They are usually small (ranging from 20 to 60 nucleotides, single-stranded DNA or RNA oligonucleotides which are capable of binding to molecules possessing high affinity and other properties like specificity. This review focuses on different aspects of Aptamers in drug discovery, starting from its preparation methods and covering the recent scenario reported in the literature regarding their use in drug discovery. We address the limitations of Aptamers and provide valuable insights into their future potential in the areas regarding drug discovery research. Finally, we explained the major role of Aptamers like medical imaging techniques, application as synthetic antibodies, and the most recent application, which is in combination with nanomedicines.

Synthesis of an N-Heterocyclic Carbene-based Au(I) Coordinate Surfactant: Application for Alkyne Hydration Based on Au Nanoparticle Formation

In this study, an N-heterocyclic carbene (NHC)-based metal coordinate surfactant (MCS), NHC-Au-MCS, in which the NHC framework afforded the bonding of the Au(I) at the linkage of the hydrophilic and hydrophobic moieties, was synthesized. The structure of NHC-Au-MCS was confirmed by ¹H and ¹³C NMR spectroscopic measurements together with elemental analysis. Matrix-assisted laser desorption/ionization (MALDI), laser desorption/ionization (LDI), and electrospray ionization mass spectrometry (ESI-MS) indicated the distinct reactivity of NHC-Au-MCS, such as the exchange of Br to Cl and the formation of a cationic Au complex, where the two NHC ligands were coordinated to an Au(I) center upon laser activation. The surface tension and dynamic light scattering (DLS) measurements revealed that the coordination of Au(I) to NHC reduced the critical micelle concentration (CMC) of NHC-Au-MCS (1.3×10^-5 M), which resulted in the formation of micelles at concentrations higher than the CMC in water. We also confirmed that the surface-active Au(I) complex of NHC-Au-MCS catalyzed the hydration of 1-dodecyne to 2-dodecanone in water in the absence of an organic solvent. On the basis of the detailed mechanistic investigations regarding the reactivity of NHC-Au-MCS, we revealed that NHC-Au-MCS partially translated into Au nanoparticles (AuNPs), which facilitated alkyne hydration. These mechanistic studies were supported by UV-vis measurements, transmission electron microscopy (TEM), and LDI-MS.

Synergistically dual-functional nano eye-drops for simultaneous anti-inflammatory and anti-oxidative treatment of dry eye disease

We have developed a rapid and straightforward topical treatment method for dry eye disease (DED) using poly(catechin) capped-gold nanoparticles (Au@Poly-CH NPs) carrying amfenac [AF; a nonsteroidal anti-inflammatory drug (NSAID)] through effective attenuation of ocular surface tissue damage in dry eyes. A dual-targeted strategy based on ocular therapeutics was adopted to simultaneously block the cyclooxygenase enzymes-induced inflammation and reactive oxygen species (ROS)-induced oxidative stress, the primary two causes of DED. The self-assembled core-shell Au@Poly-CH NPs synthesized via a simple reaction between tetrachloroaurate(iii) and catechin possess a poly(catechin) shell (∼20 nm) on the surface of each Au NP (∼60 nm). The anti-oxidant and anti-inflammatory properties of AF/Au@Poly-CH NPs were evaluated by DCFH-DA and prostaglandin E2/VEGF assays, respectively. Our results demonstrate that Au@Poly-CH NPs not only act as an anti-oxidant to suppress ROS-mediated processes, but also serve as a drug carrier of AF for a synergistic effect on anti-inflammation. In vivo biocompatibility studies show good tolerability of AF/Au@Poly-CH NPs for potential use in the treatment of ocular surface pathologies. The dual-targeted therapeutic effects of AF/Au@Poly-CH NPs lead to rapid recovery from DED in a rabbit model. Au@Poly-CH NPs loaded with NSAIDs is a promising multifunctional nanocomposite for treating various inflammation- and oxidative stress-related diseases.

Targeted Molecular Imaging Using Aptamers in Cancer

Imaging is not only seeing, but also believing. For targeted imaging modalities, nucleic acid aptamers have features such as superior recognition of structural epitopes and quick uptake in target cells. This explains the emergence of an evolved new class of aptamers into a wide spectrum of imaging applications over the last decade. Genetically encoded biosensors tagged with fluorescent RNA aptamers have been developed as intracellular imaging tools to understand cellular signaling and physiology in live cells. Cancer-specific aptamers labeled with fluorescence have been used for assessment of clinical tissue specimens. Aptamers conjugated with gold nanoparticles have been employed to develop innovative mass spectrometry tissue imaging. Also, use of chemically conjugated cancer-specific aptamers as probes for non-invasive and high-resolution imaging has been transformative for in vivo imaging in multiple cancers.