Gold nanostar and graphitic carbon nitride nanocomposite for serotonin detection in biological fluids and human embryonic kidney cell microenvironment.

A nanosensor comprising of gold nanostars (Au-Nstars)-graphitic carbon nitride (g-CN) nanocomposite layered on a glassy carbon electrode (GCE) to detect serotonin (ST) in various body fluids has been fabricated. The nanocomposite and the sensing platform have been thoroughly characterized with UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive X-ray photoelectron spectroscopy (EDX), and electrochemical techniques such as cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The designed ST detection probe has achieved a linear dynamic range (LDR) in the range 5 × 10 and 1 × 10 M with a limit of detection (LOD) of 15.

pH-Responsive PEGylated Niosomal Nanoparticles as an Active-Targeting Cyclophosphamide Delivery System for Gastric Cancer Therapy.

A PEGylated niosomal formulation of cyclophosphamide (Nio-Cyclo-PEG) was prepared using a central composite design and characterized in terms of drug loading, size distribution, and average size. The stability of formulations was also studied at different conditions. In vitro cytotoxicity of drug delivery formulations was assessed on gastric cancer cells using MTT assay.

Emerging Strategies in Enhancing Singlet Oxygen Generation of Nano-Photosensitizers Toward Advanced Phototherapy.

The great promise of photodynamic therapy (PDT) has thrusted the rapid progress of developing highly effective photosensitizers (PS) in killing cancerous cells and bacteria. To mitigate the intrinsic limitations of the classical molecular photosensitizers, researchers have been looking into designing new generation of nanomaterial-based photosensitizers (nano-photosensitizers) with better photostability and higher singlet oxygen generation (SOG) efficiency, and ways of enhancing the performance of existing photosensitizers. In this paper, we review the recent development of nano-photosensitizers and nanoplasmonic strategies to enhance the SOG efficiency for better PDT performance.

Gold Nanostars-AIE Theranostic Nanodots with Enhanced Fluorescence and Photosensitization Towards Effective Image-Guided Photodynamic Therapy.

Dual-functional aggregation-induced photosensitizers (AIE-PSs) with singlet oxygen generation (SOG) ability and bright fluorescence in aggregated state have received much attention in image-guided photodynamic therapy (PDT). However, designing an AIE-PS with both high SOG and intense fluorescence via molecular design is still challenging. In this work, we report a new nanohybrid consisting of gold nanostar (AuNS) and AIE-PS dots with enhanced fluorescence and photosensitization for theranostic applications.

Colorimetric biosensors for point-of-care virus detections.

Colorimetric biosensors can be used to detect a particular analyte through color changes easily by naked eyes or simple portable optical detectors for quantitative measurement. Thus, it is highly attractive for point-of-care detections of harmful viruses to prevent potential pandemic outbreak, as antiviral medication must be administered in a timely fashion. This review paper summaries existing and emerging techniques that can be employed to detect viruses through colorimetric assay design with detailed discussion of their sensing principles, performances as well as pros and cons, with an aim to provide guideline on the selection of suitable colorimetric biosensors for detecting different species of viruses.

Insights and Perspectives Regarding Nanostructured Fluorescent Materials toward Tackling COVID-19 and Future Pandemics.

The COVID-19 outbreak has exposed the world's preparation to fight against unknown/unexplored infectious and life-threatening pathogens. The unavailability of vaccines, slow or sometimes unreliable real-time virus/bacteria detection techniques, insufficient personal protective equipment (PPE), and a shortage of ventilators and many other transportation equipments have further raised serious concerns. Material research has been playing a pivotal role in developing antimicrobial agents for water treatment and photodynamic therapy, fast and ultrasensitive biosensors for virus/biomarkers detection, as well as for relevant biomedical and environmental applications.

Point of care detection of COVID-19: Advancement in biosensing and diagnostic methods.

The recent outbreak of COVID-19 has created much inconvenience and fear that the virus can seriously affect humans, causing health hazards and death. This pandemic has created much worry and as per the report by World Health Organization (WHO), more than 43 million individuals in 215 countries and territories were affected. People around the world are still struggling to overcome the problems associated with this pandemic.

Metal Nanoparticles-Enhanced Biosensors: Synthesis, Design and Applications in Fluorescence Enhancement and Surface-enhanced Raman Scattering.

Metal nanoparticles (NP) that exhibit localized surface plasmon resonance play an important role in metal-enhanced fluorescence (MEF) and surface-enhanced Raman scattering (SERS). Among the optical biosensors, MEF and SERS stand out to be the most sensitive techniques to detect a wide range of analytes from ions, biomolecules to macromolecules and microorganisms. Particularly, anisotropic metal NPs with strongly enhanced electric field at their sharp corners/edges under a wide range of excitation wavelengths are highly suitable for developing the ultrasensitive plasmon-enhanced biosensors.

Establishing empirical design rules of nucleic acid templates for the synthesis of silver nanoclusters with tunable photoluminescence and functionalities towards targeted bioimaging applications.

DNA-templated silver nanoclusters (AgNCs) are an emerging class of ultrasmall (<2 nm) fluorophores with increasing popularity for bioimaging due to their facile synthesis and tunable emission color. However, design rules correlating different nucleotide sequences with the photoemission properties of AgNCs are still largely unknown, preventing the rational design of DNA templates to fine-tune the emission color, brightness and functionalities of AgNCs for any targeted applications. Herein, we report a systematic investigation to understand the empirical influences of the four basic DNA nucleotides on AgNC synthesis and their effects on photoluminescence properties.

Metal-enhancement study of dual functional photosensitizers with aggregation-induced emission and singlet oxygen generation.

Photosensitizers with aggregation-induced emission (AIE-PS) are attractive for image-guided photodynamic therapy due to their dual functional role in generating singlet oxygen and producing high fluorescent signal in the aggregated state. However, their brightness and treatment efficiency maybe limited in current practice. Herein we report the first systematic investigation on the metal-enhanced fluorescence (MEF) and singlet oxygen generation (ME-SOG) ability of our newly synthesized AIE-photosensitizers.

Protein-protected gold/silver alloy nanoclusters in metal-enhanced singlet oxygen generation and their correlation with photoluminescence.

Photoluminescent noble metal nanoclusters (NCs, core size <2 nm) have recently emerged as a new type of photosensitizers advantageous over conventional photosensitizers due to their high singlet oxygen (O) generation efficiency, excellent photostability and water solubility, as well as good biocompatibility for photodynamic therapy and bioimaging. However, no correlation has been established between the intrinsic O generation and photoluminescence properties of metal NCs with their size, composition, and concentration, which is important to customize the molecule-like properties of NCs for different applications. Herein, we report a systematic study to uncover the rational design of bimetallic NCs with controllable O generation efficiency by tuning their compositions through spontaneous galvanic displacement reaction.

Simulation guided design of silver nanostructures for plasmon-enhanced fluorescence, singlet oxygen generation and SERS applications.

Plasmonic nanostructures such as gold and silver could alter the intrinsic properties of fluorophores, photosensitizers or Raman reporters in their close vicinity. In this study, we have conducted systematic simulations to provide insight for the design of silver nanostructures with appropriate geometrical features for metal-enhanced fluorescence (MEF), metal-enhanced singlet oxygen generation (ME-SOG) and surface-enhanced Raman scattering (SERS) applications. The size-dependent optical properties and electric field enhancement of single and dimeric nanocubes were simulated.

Noncovalent Fluorescent Biodot-Protein Conjugates with Well-Preserved Native Functions for Improved Sweat Glucose Detection.

To overcome the traditional issues of protein labeling, we report herein an effective approach for noncovalent conjugation of the biomolecule-derived fluorescent nanodots (biodot) to functional proteins without the addition of chemical linkers for biosensor development. The as-prepared fluorescent biodot-protein conjugates are very stable near physiological pH, exhibiting excellent photostability and thermal stability. More importantly, the native functions of proteins, including drug binding and enzymatic activities, are well-preserved after conjugating with biodots.

Recent development of nucleic acid nanosensors to detect sequence-specific binding interactions: From metal ions, small molecules to proteins and pathogens.

DNA carries important genetic instructions and plays vital roles in regulating biological activities in living cells. Proteins such as transcription factors binds to DNA to regulate the biological functions of DNA, and similarly many drug molecules also bind to DNA to modulate its functions. Due to the importance of protein-DNA and drug-DNA binding, there has been intense effort in developing novel nanosensors in the same length scale as DNA, to effectively study these binding interactions in details.

Development of Blood-Cell-Selective Fluorescent Biodots for Lysis-Free Leukocyte Imaging and Differential Counting in Whole Blood.

Complete blood count with leukocyte (white blood cell, WBC) differential is one of the most frequently ordered clinical test for disease diagnosis. Herein, multifunctional fluorescent carbon dots derived from biomolecules (biodots) for rapid lysis-free whole blood analysis are developed. Specifically, two types of biodots are molecularly engineered through hydrothermal synthesis for differential blood cells labeling.

Nanodot-Directed Formation of Plasmonic-Fluorescent Nanohybrids toward Dual Optical Detection of Glucose and Cholesterol via Hydrogen Peroxide Sensing.

Hybrid nanoparticles (NPs) have emerged as an important class of nanomaterials owing to their integrated enhanced properties and functionality. In this study, we have developed an effective nanodot templating strategy for the in situ formation of surfactant-free nanohybrids with unique plasmonic-fluorescent properties. A bright photoluminescent biodot synthesized from serine and histamine biomolecular precursors (Ser-Hist dot) was first engineered to have rich functional groups on the nanosurface capable of anchoring Ag ions via electrostatic interaction.

Nucleotide-derived theranostic nanodots with intrinsic fluorescence and singlet oxygen generation for bioimaging and photodynamic therapy.

Nucleic acids are important molecules of life and have recently emerged as important functional materials to synthesize, organize and assemble inorganic nanoparticles for various technological applications. In this study, we have systematically investigated the four basic nucleotides of DNA as precursors to form fluorescent nucleotide derived biodots (N-dots) with unique singlet oxygen generation properties by one-pot hydrothermal synthesis. It has been discovered for the first time that the nitrogenous base adenine accounts for the bright fluorescence, while the sugar and phosphate groups of the nucleotide endow the N-dots with good photo-stability.

Seeds, fermented foods, and agricultural by-products as sources of plant-derived antibacterial peptides.

The emergence of bacterial resistance against conventional antibiotics and the growing interest in developing alternative, natural antibacterial agents have prompted the search for plant-derived antibacterial peptides in recent decades. Different classes of endogenous antibacterial peptides have been identified from various plant species. Moreover, protein hydrolysates and hydrolysate-derived peptides with potent antibacterial effects have also been identified from numerous plant sources.

Uncovering the Design Principle of Amino Acid-Derived Photoluminescent Biodots with Tailor-Made Structure-Properties and Applications for Cellular Bioimaging.

Natural amino acids possess side chains with different functional groups (R groups), which make them excellent precursors for programmable synthesis of biomolecule-derived nanodots (biodots) with desired properties. Herein, we report the first systematic study to uncover the material design rules of biodot synthesis from 20 natural α-amino acids via a green hydrothermal approach. The as-synthesized amino acid biodots (AA dots) are comprehensively characterized to establish a structure-property relationship between the amino acid precursors and the corresponding photoluminescent properties of AA dots.

Rapid colorimetric detection of p53 protein function using DNA-gold nanoconjugates with applications for drug discovery and cancer diagnostics.

The tumor suppressor protein p53 plays a central role in preventing cancer through interaction with DNA response elements (REs) to regulate target gene expression in cells. Due to its significance in cancer biology, relentless efforts have been directed toward understanding p53-DNA interactions for the development of cancer therapeutics and diagnostics. In this paper, we report a rapid, label-free and versatile colorimetric assay to detect wildtype p53 DNA-binding function in complex solutions.

Locked Nucleic Acid Gapmers and Conjugates Potently Silence ADAM33, an Asthma-Associated Metalloprotease with Nuclear-Localized mRNA.

Two mechanisms dominate the clinical pipeline for oligonucleotide-based gene silencing, namely, the antisense approach that recruits RNase H to cleave target RNA and the RNAi approach that recruits the RISC complex to cleave target RNA. Multiple chemical designs can be used to elicit each pathway. We compare the silencing of the asthma susceptibility gene ADAM33 in MRC-5 lung fibroblasts using four classes of gene silencing agents, two that use each mechanism: traditional duplex small interfering RNAs (siRNAs), single-stranded small interfering RNAs (ss-siRNAs), locked nucleic acid (LNA) gapmer antisense oligonucleotides (ASOs), and novel hexadecyloxypropyl conjugates of the ASOs.

Biomimicking synthesis of photoluminescent molecular lantern catalyzed by in-situ formation of nanogold catalysts.

Bioluminescence has been widely recognized as a powerful imaging tool for biological investigations. Synthesis of molecular lanterns that mimic bioluminescence in nature is of great interest. Herein we report a synthesis of molecular lantern by utilizing the catalytic properties of ultrasmall (<2nm) gold nanoclusters (AuNC), which is inspired by the enzymatic light-up of luciferin in the biological system.

Fatty acid translocase gene CD36 rs1527483 variant influences oral fat perception in Malaysian subjects.

We determined whether single nucleotide polymorphisms (SNPs; rs1761667 and rs1527483) in the fatty acid translocase CD36 gene - a receptor for fatty acids - is associated with oral fat perception (OFP) of different fat contents in custards and commercially-available foods, and obesity measures in Malaysian subjects (n=313; 118 males, 293 ethnic Chinese; 20 ethnic Indians). A 170-mm visual analogue scale was used to assess the ratings of perceived fat content, oiliness and creaminess of 0%, 2%, 6% and 10% fat content-by-weight custards and low-fat/regular versions of commercially-available milk, mayonnaise and cream crackers. Overall, the subjects managed to significantly discriminate the fat content, oiliness and creaminess between low-fat/regular versions of milk and mayonnaise.

Bovine Serum Albulmin Protein-Templated Silver Nanocluster (BSA-Ag ): An Effective Singlet Oxygen Generator for Photodynamic Cancer Therapy.

This paper reports a novel synthesis approach of bovine serum albumin (BSA) protein-templated ultrasmall (<2 nm) Ag nanocluster (NC) with strong singlet oxygen generation capacity for photodynamic therapy (PDT). An atomically precise BSA-Ag NC (i.e.

Rational Design of Biomolecular Templates for Synthesizing Multifunctional Noble Metal Nanoclusters toward Personalized Theranostic Applications.

Biomolecule-templated or biotemplated metal nanoclusters (NCs) are ultrasmall (<2 nm) metal (Au, Ag) particles stabilized by a certain type of biomolecular template (e.g., peptides, proteins, and DNA).