Microscale Humidity Sensor Based on Iron-Coated Elaters of Spores.

Humidity sensors deeply influence human manufacturing production and daily life, while researchers generally focus on developing humidity sensors with higher stability, higher linearity, rapid response time, etc. Yet, few people discuss measuring humidity in the microenvironment by miniaturizing sensor size into a microscale, in which the existing humidity sensors are difficult to reach. Accordingly, this study proposes a methodology for measuring relative humidity in the microscale by utilizing the distinctive morphologies of spores across a range of relative humidities between 50% and 90%.

Nano/Micromotors for Cancer Diagnosis and Therapy: Innovative Designs to Improve Biocompatibility.

Nano/micromotors are artificial robots at the nano/microscale that are capable of transforming energy into mechanical movement. In cancer diagnosis or therapy, such "tiny robots" show great promise for targeted drug delivery, cell removal/killing, and even related biomarker sensing. Yet biocompatibility is still the most critical challenge that restricts such techniques from transitioning from the laboratory to clinical applications.

Smartphone-based hand-held polarized light microscope for on-site pharmaceutical crystallinity characterization.

Polarized light microscopy (PLM) is a common but critical method for pharmaceutical crystallinity characterization, which has been widely introduced for research purposes or drug testing and is recommended by many pharmacopeias around the world. To date, crystallinity characterization of pharmaceutical solids is restricted to laboratories due to the relatively bulky design of the conventional PLM system, while little attention has been paid to on-site, portable, and low-cost applications. Herein, we developed a smartphone-based polarized microscope with an ultra-miniaturization design ("hand-held" scale) for these purposes.

Nanomaterials meet surface-enhanced Raman scattering towards enhanced clinical diagnosis: a review.

Surface-enhanced Raman scattering (SERS) is a very promising tool for the direct detection of biomarkers for the diagnosis of i.e., cancer and pathogens.

On-board smartphone micromotor-based fluorescence assays.

Herein, we describe the design of a portable device integrated with micromotors for real-time fluorescence sensing of (bio)markers. The system comprises a universal 3D printed platform to hold a commercial smartphone, which is equipped with an external magnification optical lens (20-400×) and tailor-made emission filters directly attached to the camera, an adjustable sample holder to accommodate a glass slide and laser excitation sources. On a first approach, we illustrate the suitability of the platform using magnetic Janus micromotors modified with fluorescent ZnS@CdSe quantum dots for real-time ON-OFF mercury detection.

Smartphone-Based Janus Micromotors Strategy for Motion-Based Detection of Glutathione.

Herein, we describe a Janus micromotor smartphone platform for the motion-based detection of glutathione. The system compromises a universal three-dimensional (3D)-printed platform to hold a commercial smartphone, which is equipped with an external magnification optical lens (20-400×) directly attached to the camera, an adjustable sample holder to accommodate a glass slide, and a light-emitting diode (LED) source. The presence of glutathione in peroxide-rich sample media results in the decrease in the speed of 20 μm graphene-wrapped/PtNPs Janus micromotors due to poisoning of the catalytic layer by a thiol bond formation.

Real-time monitoring of aristolochic acid I reduction process using surface-enhanced Raman Spectroscopy with DFT simulation.

With the increasing number of reports on aristolochic acid I (AAI), more and more toxic and side effects have been discovered successively. The main recognized carcinogenic mechanism is that AAI is metabolized into aristololactam I (AAT) in the body by nitroreductases, ultimately forming AAT-DNA adducts that cause disease. However, the carcinogenic mechanism is still not well understood by currently reported indirect method, there has always been a great demand to develop a direct method for real-time monitoring such process.

Dual-Propelled Lanbiotic Based Janus Micromotors for Selective Inactivation of Bacterial Biofilms.

Graphene oxide/PtNPs/Fe O "dual-propelled" catalytic and fuel-free rotary actuated magnetic Janus micromotors modified with the lanbiotic Nisin are used for highly selective capture/inactivation of gram-positive bacteria units and biofilms. Specific interaction of Nisin with the Lipid II unit of Staphylococcus Aureus bacteria in connection with the enhanced micromotor movement and generated fluid flow result in a 2-fold increase of the capture/killing ability (both in bubble and magnetic propulsion modes) as compared with free peptide and static counterparts. The high stability of Nisin along with the high towing force of the micromotors allow for efficient operation in untreated raw media (tap water, juice and serum) and even in blood and in flowing blood in magnetic mode.

Janus Micromotors Coated with 2D Nanomaterials as Dynamic Interfaces for (Bio)-Sensing.

In this work, we study the interaction of graphdiyne oxide (GDYO)-, graphene oxide (GO)-, or black phosphorous (BP)-wrapped Janus micromotors using a model system relying on a fluorescence-labeled affinity peptide, which is released upon specific interaction with a target Cholera Toxin B. Such ON-OFF-ON system allows mimicking similar processes occurring at (bio)-interfaces and to study the related sorption and desorption kinetics. The distinct surface properties of each nanomaterial play a critical role in the loading/release capacity of the peptide, greatly influencing the release profiles.

Light-driven nanomotors and micromotors: envisioning new analytical possibilities for bio-sensing.

The aim of this conceptual review is to cover recent developments of light-propelled micromotors for analytical (bio)-sensing. Challenges of self-propelled light-driven micromotors in complex (biological) media and potential solutions from material aspects and propulsion mechanism to achieve final analytical detection for in vivo and in vitro applications will be comprehensively covered. Graphical abstract.

Graphdiyne Micromotors in Living Biomedia.

Graphdiyne (GDY), a new kind of two-dimensional (2D) material, was combined with micromotor technology for "on-the-fly" operations in complex biomedia. Microtubular structures were prepared by template deposition on membrane templates, resulting in functional structures rich in sp and sp carbons with highly conjugated π networks. This resulted in a highly increased surface area for a higher loading of anticancer drugs or enhanced quenching ability over other 2D based micromotors, such as graphene oxide (GO) or smooth tubular micromotors.

Nano/Micromotors for Diagnosis and Therapy of Cancer and Infectious Diseases.

Micromotors are man-made nano/microscale devices capable of transforming energy into mechanical motion. The accessibility and force offered by micromotors hold great promise to solve complex biomedical challenges. This Review highlights current progress and prospects in the use of nano and micromotors for diagnosis and treatment of infectious diseases and cancer.

Correction: Antimicrobial peptide based magnetic recognition elements and Au@Ag-GO SERS tags with stable internal standards: a three in one biosensor for isolation, discrimination and killing of multiple bacteria in whole blood.

[This corrects the article DOI: 10.1039/C8SC04637A.].

Antimicrobial peptide based magnetic recognition elements and Au@Ag-GO SERS tags with stable internal standards: a three in one biosensor for isolation, discrimination and killing of multiple bacteria in whole blood.

In this study, a new biosensor based on a sandwich structure has been developed for the isolation and detection of multiple bacterial pathogens magnetic separation and SERS tags. This novel assay relies on antimicrobial peptide (AMP) functionalized magnetic nanoparticles as "capturing" probes for bacteria isolation and gold coated silver decorated graphene oxide (Au@Ag-GO) nanocomposites modified with 4-mercaptophenylboronic acid (4-MPBA) as SERS tags. When different kinds of bacterial pathogens are combined with the SERS tags, the "fingerprints" of 4-MPBA show corresponding changes due to the recognition interaction between 4-MPBA and different kinds of bacterial cell wall.

Strongly fluorescent cysteamine-coated copper nanoclusters as a fluorescent probe for determination of picric acid.

This paper describes the synthesis of fluorescent copper nanoclusters (CuNC) with a fluorescence quantum yield as high as 2.3% after modification with cysteamine. The modified CuNC are shown to be viable probes for the determination of picric acid (PA).

Self-Assembly of Au@Ag Nanoparticles on Mussel Shell To Form Large-Scale 3D Supercrystals as Natural SERS Substrates for the Detection of Pathogenic Bacteria.

Herein, we developed a natural surface-enhanced Raman scattering (SERS) substrate based on size-tunable Au@Ag nanoparticle-coated mussel shell to form large-scale three-dimensional (3D) supercrystals (up to 10 cm) that exhibit surface-laminated structures and crossed nanoplates and nanochannels. The high content of CaCO in the mussel shell results in superior hydrophobicity for analyte enrichment, and the crossed nanoplates and nanochannels provided rich SERS hot spots, which together lead to high sensitivity. Finite-difference time-domain simulations showed that nanoparticles in the channels exhibit apparently a higher electromagnetic field enhancement than nanoparticles on the platelets.

Chip-based dual-molecularly imprinted monolithic capillary array columns coated Ag/GO for selective extraction and simultaneous determination of bisphenol A and nonyl phenol in fish samples.

An analytical technique for selective, simultaneous determination of bisphenol A (BPA) and nonyl phenol (NP) in fish samples was established by a solid-phase extraction chip integrated with array columns of dual-molecularly imprinted polymer-coated silver-modified graphene oxide (Ag/GO-dual-MISPE-chip). Ag/GO dual-molecularly imprinted polymers (Ag/GO-dual-MIPs) were synthesized by in situ polymerization using Ag/GO as the supporting matrix which extracted templates easily. The affinity and specificity on the Ag/GO-dual-MISPE monolithic column were also investigated.

Chip-based molecularly imprinted monolithic capillary array columns coated GO/SiO2 for selective extraction and sensitive determination of rhodamine B in chili powder.

A novel solid-phase extraction chip embedded with array columns of molecularly imprinted polymer-coated silanized graphene oxide (GO/SiO2-MISPE) was established to detect trace rhodamine B (RB) in chili powder. GO/SiO2-MISPE monolithic columns for RB detection were prepared by optimizing the supporting substrate, template, and polymerizing monomer under mild water bath conditions. Adsorption capacity and specificity, which are critical properties for the application of the GO/SiO2-MISPE monolithic column, were investigated.

A simple and compact fluorescence detection system for capillary electrophoresis and its application to food analysis.

A novel fluorescence detection system for CE was described and evaluated. Two miniature laser pointers were used as the excitation source. A Y-style optical fiber was used to transmit the excitation light and a four-branch optical fiber was used to collect the fluorescence.

Molecularly imprinted coated graphene oxide solid-phase extraction monolithic capillary column for selective extraction and sensitive determination of phloxine B in coffee bean.

A method was developed to sensitively determine phloxine B in coffee bean by molecularly imprinted polymers (MIPs) coated graphene oxide (GO) solid-phase extraction (GO-MISPE) coupled with high-performance liquid chromatography and laser-induced fluorescence detection (HPLC-LIF). The GO-MISPE capillary monolithic column was prepared by water-bath in situ polymerization, using GO as supporting material, phloxine B, methacrylic acid (MAA), and ethylene dimethacrylate (EDMA) as template, functional monomer, and cross-linker, respectively. The properties of the homemade GO-MISPE capillary monolithic column, including capacity and specificity, were investigated under optimized conditions.