State Key Laboratory of Analytical Chemistry for Life Science

The evolution of photoelectrochemical (PEC) bioanalysis has resulted in substantial progress in its analytical performance and biodetection applications. The aim of this review is to provide a panoramic snapshot of the state of the art in this dynamically developing field, with special emphasis on PEC DNA analysis, immunoassay, enzymatic biosensing and cell-related detection. The future prospects in this area are also evaluated and discussed. This work will serve as a useful source to inform the interested audience of the latest developments and applications in the field of PEC bioanalysis.

Platinum-based anticancer drugs occupy a crucial role in the treatment of various malignant tumours. However, the efficacy and applicability of platinum drugs are heavily restricted by severe systemic toxicities and drug resistance. Different drug targeting and delivery (DTD) strategies have been developed to prevent the shortcomings of platinum-based chemotherapy. These approaches can be roughly categorized into two groups; namely, active and passive tactics. Active DTD is realized through specific molecular interactions between the drugs and cell or tissue elements, while passive DTD is achieved by exploiting the enhanced permeability and retention effect in tumour tissues. The principal methods for active DTD include conjugation of platinum drugs with selective targeting moieties or encapsulation of platinum drugs in host molecules. Bioactive substances such as hormones, carbohydrates, bisphosphonates, peptides and proteins are commonly used in active DTD. Passive DTD generally involves the fabrication of functionalized polymers or nanoparticles and the subsequent conjugation of platinum drugs with such entities. Polymeric micelles, liposomes, nanotubes and nanoparticles are frequently used in passive DTD. In some cases, both active and passive mechanisms are involved in one DTD system. This review concentrates on various targeting and delivery techniques for improving the efficacy and reducing the side effects of platinum-based anticancer drugs. The content covers most of the related literatures published since 2006. These innovative tactics represent current state-of-the-art developments in platinum-based anticancer drugs.

Here, an integrated cascade nanozyme with a formulation of Pt@PCN222-Mn is developed to eliminate excessive reactive oxygen species (ROS). This nanozyme mimics superoxide dismutase by incorporation of a Mn-[5,10,15,20-tetrakis(4-carboxyphenyl)porphyrinato]-based metal-organic framework compound capable of transforming oxygen radicals to hydrogen peroxide. The second mimicked functionality is that of catalase by incorporation of Pt nanoparticles, which catalyze hydrogen peroxide disproportionation to water and oxygen. Both in vitro and in vivo experimental measurements reveal the synergistic ROS-scavenging capacity of such an integrated cascade nanozyme. Two forms of inflammatory bowel disease (IBD; i.e., ulcerative colitis and Crohn's disease) can be effectively relieved by treatment with the cascade nanozyme. This study not only provides a new method for constructing enzyme-like cascade systems but also illustrates their efficient therapeutic promise in the treatment of in vivo IBDs.

Spatiotemporal control of singlet oxygen ((1)O2) release is a major challenge for photodynamic therapy (PDT) against cancer with high therapeutic efficacy and minimum side effects. Here a selenium-rubyrin (NMe2Se4N2)-loaded nanoparticle functionalized with folate (FA) was designed and synthesized as an acidic pH-activatable targeted photosensitizer. The nanoparticles could specifically recognize cancer cells via the FA-FA receptor binding and were selectively taken up by cancer cells via receptor-mediated endocytosis to enter lysosomes, in which NMe2Se4N2 was activated to produce (1)O2. The pH-controllable release of (1)O2 specially damaged the lysosomes and thus killed cancer cells in a lysosome-associated pathway. The introduction of selenium into the rubyrin core enhanced the (1)O2 generation efficiency due to the heavy atom effect, and the substitution of dimethylaminophenyl moiety at meso-position led to the pH-controllable activation of NMe2Se4N2. Under near-infrared (NIR) irradiation, NMe2Se4N2 possessed high singlet oxygen quantum yield (ΦΔ) at an acidic pH (ΦΔ = 0.69 at pH 5.0 at 635 nm) and could be deactivated at physiological pH (ΦΔ = 0.06 at pH 7.4 at 635 nm). The subcellular location-confined pH-activatable photosensitization at NIR region and the cancer cell-targeting feature led to excellent capability to selectively kill cancer cells and prevent the damage to normal cells, which greatly lowered the side effects. Through intravenous injection of FA-NMe2Se4N2 nanoparticles in tumor-bearing mice, tumor elimination was observed after NIR irradiation. This work presents a new paradigm for specific PDT against cancer and provides a new avenue for preparation of highly efficient photosensitizers.

The application of Ru nanoparticles as a cathode catalyst significantly promotes the reversibility of Li–CO₂ batteries.

Abstract Safe, effective, and convenient administration of therapeutic nanomaterials is one of the greatest difficulties in nanomedicine. To tackle this challenge, a system which couples multi‐enzyme mimicking CeO 2 nanoparticles with clinically approved montmorillonite (MMT) for inflammatory bowel disease (IBD) therapy is reported. CeO 2 exhibits superoxide dismutase‐ and catalase‐like activities, and hydroxyl radical scavenging activity, making it more efficient at scavenging reactive oxygen species (ROS) than non‐catalytic antioxidants while being more stable than free enzymes. In addition, negatively‐charged MMT can be orally administered and specifically adsorbed onto positively‐charged inflamed colon tissue via electrostatic interactions for targeted delivery. When the two are assembled together by in situ growth of CeO 2 onto MMT, the optimized CeO 2 @MMT(1:9) is stable in the stomach for oral delivery, targets the inflamed colon through electrostatic interactions, and reduces inflammation through ROS scavenging, all without any significant systemic exposure as demonstrated by the relief of murine IBD in vivo.

During the past decade, biofuel cells (BFCs) have emerged as an emerging technology on account of their ability to directly generate electricity from biologically renewable catalysts and fuels. Due to the boost in nanotechnology, significant advances have been accomplished in BFCs. Although it is still challenging to promote the performance of BFCs, adopting nanostructured materials for BFC construction has been extensively proposed as an effective and promising strategy to achieve high energy production. In this review, we presented the major novel nanostructured materials applied for BFCs and highlighted the breakthroughs in this field. Based on different natures of the bio-catalysts and electron transfer process at the bio-electrode surfaces, the fundamentals of BFC systems, including enzymatic biofuel cells (EBFCs) and microbial fuel cells (MFCs), have been elucidated. In particular, the principle of electrode materials design has been detailed in terms of enhancing electrical communications between biological catalysts and electrodes. Furthermore, we have provided the applications of BFCs and potential challenges of this technology.

Highly efficient light-harvesting systems were successfully fabricated in aqueous solution based on the supramolecular self-assembly of a water-soluble pillar[6]arene (WP6), a salicylaldehyde azine derivative (G), and two different fluorescence dyes, Nile Red (NiR) or Eosin Y (ESY). The WP6-G supramolecular assembly exhibits remarkably improved aggregation-induced emission enhancement and acts as a donor for the artificial light-harvesting system, and NiR or ESY, which are loaded within the WP6-G assembly, act as acceptors. An efficient energy-transfer process takes place from the WP6-G assembly not only to NiR but also to ESY for these two different systems. Furthermore, both of the WP6-G-NiR and WP6-G-ESY systems show an ultrahigh antenna effect at a high donor/acceptor ratio.

Pesticides, widely used for pest control and plant growth regulation, have posed a threat to the environment and human health. Conventional methods to analyze pesticide residues are not applied to resource-limited areas because of their high cost, complexity, and requirements for expensive instruments (such as GC/MS and LC/MS). To address these challenges, herein we fabricated colorimetric nanozyme sensor arrays based on heteroatom-doped graphene for detection of aromatic pesticides. The active sites of nanozymes could be differentially masked when different pesticides were adsorbed on the graphene, which in turn resulted in the decrease of their peroxidase-mimicking activities. On the basis of this principle, five pesticides (i.e., lactofen, fluoroxypyr-meptyl, bensulfuron-methyl, fomesafen, and diafenthiuron) from 5 to 500 μM were successfully discriminated by the sensor arrays. In addition, discrimination for different concentrations of each pesticide and different ratios of two mixed pesticides were also demonstrated. The practical application of the sensor arrays was further validated by successfully discriminating the pesticides in soil samples. This work not only provides a facile and cost-effective method to detect pesticides but also makes a positive contribution to food safety and environmental protection.

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTPhotoelectrochemical ImmunoassaysWei-Wei Zhao*†‡, Jing-Juan Xu†, and Hong-Yuan Chen†View Author Information† State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P.R. China‡ Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States*E-mail: [email protected] or [email protected]. Phone/Fax: +86-25-89684862.Cite this: Anal. Chem. 2018, 90, 1, 615–627Publication Date (Web):November 14, 2017Publication History Published online21 November 2017Published inissue 2 January 2018https://pubs.acs.org/doi/10.1021/acs.analchem.7b04672https://doi.org/10.1021/acs.analchem.7b04672review-articleACS PublicationsCopyright © 2017 American Chemical SocietyRequest reuse permissionsArticle Views5949Altmetric-Citations254LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Biopolymers,Immunoassays,Immunology,Peptides and proteins,Quantum dots Get e-Alerts

Metal-organic frameworks (MOFs) are an emerging class of molecular crystalline materials built from metal ions or clusters bridged by organic linkers. By taking advantage of their synthetic tunability and structural regularity, MOFs can hierarchically integrate nanoparticles and/or biomolecules into a single framework to enable multifunctions. The MOF-protected heterostructures not only enhance the catalytic capacity of nanoparticle components but also retain the biological activity of biomolecules in an intracellular microenvironment. Therefore, the multifunctional MOF heterostructures have great advantages over single components in cancer therapy. In this review, we comprehensively summarize the general principle of the design and functional modulation of nanoscaled MOF heterostructures, and biomedical applications in enhanced therapy within the last five years. The functions of MOF heterostructures with a controlled size can be regulated by designing various functional ligands and in situ growth/postmodification of nanoparticles and/or biomolecules. The advances in the application of multifunctional MOF heterostructures are also explored for enhanced cancer therapies involving photodynamic therapy, photothermal therapy, chemotherapy, radiotherapy, immunotherapy, and theranostics. The remaining challenges and future opportunities in this field, in terms of precisely localized assembly, maximizing composite properties, and processing new techniques, are also presented. The introduction of multiple components into one crystalline MOF provides a promising approach to design all-in-one theranostics in clinical treatments.

Platinum-based anticancer drugs are the mainstay of chemotherapy regimens in clinic. Nevertheless, the efficacy of platinum drugs is badly affected by serious systemic toxicities and drug resistance, and the pharmacokinetics of most platinum drugs is largely unknown. In recent years, a keen interest in functionalizing platinum complexes with bioactive molecules, targeting groups, photosensitizers, fluorophores, or nanomaterials has been sparked among chemical and biomedical researchers. The motivation for functionalization comes from some of the following demands: to improve the tumor selectivity or minimize the systemic toxicity of the drugs, to enhance the cellular accumulation of the drugs, to overcome the tumor resistance to the drugs, to visualize the drug molecules in vitro or in vivo, to achieve a synergistic anticancer effect between different therapeutic modalities, or to add extra functionality to the drugs. In this Account, we present different strategies being used for functionalizing platinum complexes, including conjugation with bisphosphonates, peptides, receptor-specific ligands, polymers, nanoparticles, magnetic resonance imaging contrast agents, metal chelators, or photosensitizers. Among them, bisphosphonates, peptides, and receptor-specific ligands are used for actively targeted drug delivery, polymers and nanoparticles are for passively targeted drug delivery, magnetic resonance imaging contrast agents are for theranostic purposes, metal chelators are for the treatment or prevention of Alzheimer's disease (AD), and photosensitizers are for photodynamic therapy of cancers. The rationales behind these designs are explained and justified at the molecular or cellular level, associating with the requirements for diagnosis, therapy, and visualization of biological processes. To illustrate the wide range of opportunities and challenges that are emerging in this realm, representative examples of targeted drug delivery systems, anticancer conjugates, anticancer theranostic agents, and anti-AD compounds relevant to functionalized platinum complexes are provided. All the examples exhibit new potential of platinum complexes for future applications in biomedical areas. The emphases of this Account are placed on the functionalization for targeted drug delivery and theranostic agents. In the end, a general assessment of various strategies has been made according to their major shortcomings and defects. The original information in this Account comes entirely from literature appearing since 2010.

A sensing platform based on the fluorescence quenching ability of polydopamine nanospheres was developed for the assay of biomolecules.

The global tobacco epidemic is still a devastating threat to public health. Toxic reactive oxygen species (ROS) in the cigarette smoke cannot be efficiently eliminated by currently available cigarette filters. The resultant oxidative stress causes severe lung injury and further diseases. To tackle this challenge, herein, a novel copper tannic acid coordination (CuTA) nanozyme is reported as a highly active and thermostable ROS scavenger. The CuTA nanozyme exhibits intrinsic superoxide dismutase-like activity, catalase-like activity, and hydroxyl radical elimination capacity. These synergistic antioxidant abilities make the CuTA nanozyme a promising candidate for the improvement of commercial cigarette filters. Mouse model results show that commercial cigarettes loaded with CuTA nanozyme efficiently scavenge ROS in the cigarette smoke, reduce oxidative stress-induced lung inflammation, and minimize the resultant acute lung injury. The developed CuTA nanozyme offers an efficient ROS scavenger with multiple antioxidant ability and opens up new opportunities for the modification of cigarette filters to reduce the toxic effects of cigarette smoke.

A practical and unified strategy has been described for the preparation of mono- and difluoromethylated phenanthridine derivatives using a visible-light-promoted alkylation and decarboxylation sequence from biphenyl isocyanides with ethyl bromofluoroacetate (EBFA) or ethyl bromodifluoroacetate (EBDFA). These reactions could be carried out at room temperature in good to excellent chemical yields. Both stepwise and one-pot procedures have been developed, which makes this strategy more attractive.

Nanomaterials exhibit structural and functional heterogeneity among individual nanoparticles, thus requiring a capability to study single nanoparticles. While electron microscopes often provide static images of their chemical composition, morphology and structure, imaging the chemical activity of single nanoparticles is highly desirable for exploring the structure-activity relationship via a bottom-up strategy, to understand their microscopic reaction mechanisms and kinetics, and to identify a minority subpopulation with extraordinary activity. Recently, various optical microscopes have been emerging as powerful techniques towards this goal, owing to their non-invasive nature, excellent sensitivity, diversified spectroscopic principles and sufficient spatial and temporal resolution. In this review, we first introduce the motivational concept and the strength of using optical microscopy to study the chemical activity of single nanoparticles. In the second section, five types of commonly used optical microscopy, fluorescence microscopy, dark-field microscopy, surface plasmon resonance microscopy, Raman microscopy and photothermal microscopy are described, with an emphasis on their applicable nanomaterials and mechanisms for application. Recent achievements of these techniques in nanosensing, nanoelectrochemistry and nanocatalysis are surveyed and summarized in the subsequent sections, respectively. We finally conclude with our perspective on the remaining challenges and the future trends in this field.

A very fast-responsive fluorescent probe PZ-Py for imaging mitochondrial HClO/ClO(-), with a relatively long emission wavelength, was prepared. The limit of detection was evaluated to be 17.9 nM. Moreover, the probe PZ-Py was successfully applied in the imaging of endogenous HClO/ClO(-) in the mitochondria of RAW 264.7 cells and living nude mouse.

Highly regio- and enantioselective allylic alkylation has been achieved enabled by the merger of photoredox and palladium catalysis. In this dual catalytic process, alkyl radicals generated from 4-alkyl-1,4-dihydropyridines act as the coupling partners of the π-allyl palladium complexes. The generality of this method has been illustrated through the reaction of a variety of allyl esters with 4-alkyl-1,4-dihydropyridines. This mechanistically novel strategy expands the scope of the traditional Pd-catalyzed asymmetric allylic alkylation reaction and serves as its alternative and potential complement.

Bacterial infection is one of the major causes of human death worldwide. To prevent bacterial infectious diseases from spreading, it is of critical importance to develop convenient, ultrasensitive, and cost-efficient methods for bacteria detection. Here, an electrochemical detector of a functional two-dimensional (2D) metal–organic framework (MOF) nanozyme was developed for the sensitive detection of pathogenic Staphylococcus aureus. A dual recognition strategy consisting of vancomycin and anti-S. aureus antibody was proposed to specifically anchor S. aureus. The 2D MOFs with excellent peroxidase-like activity can efficiently catalyze o-phenylenediamine to 2,2-diaminoazobenzene, which is an ideal electrochemical signal readout for monitoring the bacteria concentration. Under optimal conditions, the present bioassay provides a wide detection range of 10–7.5 × 107 colony-forming units CFU/mL with a detection limit of 6 CFU/mL, which is better than most of the previous reports. In addition, the established electrochemical sensor can selectively and accurately identify S. aureus in the presence of other bacteria. The present work provides a new pathway for sensitive and selective detection of S. aureus and presents a promising potential in the realm of clinical diagnosis.

Abstract DNAzymes are a promising platform for metal ion detection, and a few DNAzyme‐based sensors have been reported to detect metal ions inside cells. However, these methods required an influx of metal ions to increase their concentrations for detection. To address this major issue, the design of a catalytic hairpin assembly (CHA) reaction to amplify the signal from photocaged Na + ‐specific DNAzyme to detect endogenous Na + inside cells is reported. Upon light activation and in the presence of Na + , the NaA43 DNAzyme cleaves its substrate strand and releases a product strand, which becomes an initiator that trigger the subsequent CHA amplification reaction. This strategy allows detection of endogenous Na + inside cells, which has been demonstrated by both fluorescent imaging of individual cells and flow cytometry of the whole cell population. This method can be generally applied to detect other endogenous metal ions and thus contribute to deeper understanding of the role of metal ions in biological systems.