Ultrasmall CuMn-His Nanozymes with Multienzyme Activity at Neutral pH: Construction of a Colorimetric Sensing Array for Biothiol Detection and Disease Identification.

Biothiol assays offer vital insights into health assessment and facilitate the early detection of potential health issues, thereby enabling timely and effective interventions. In this study, we developed ultrasmall CuMn-Histidine (His) nanozymes with multiple enzymatic activities. CuMn-His enhanced peroxidase (POD)-like activity at neutral pH was achieved through hydrogen bonding and electrostatic effects.

Peroxidase-like activity and mechanism of gold nanoparticle-modified TiC MXenes for the construction of HO and ampicillin colorimetric sensors.

Transition metal carbides modified by Au nanoparticles (Au/TiC) were synthesized and developed as a colorimetric sensor for the determination of HO and ampicillin. The surface electrical properties of TiC were changed, and Au nanoparticles (AuNPs) and gold growth solution were synthesized simultaneously. Au/TiC was obtained by seed growth method with AuNPs modified on the surface of transition metal carbides, nitrides or carbon-nitrides (TiC MXenes).

Ultrasmall CuO@His Nanozymes with RONS Scavenging Capability for Anti-inflammatory Therapy.

High concentrations of reactive oxygen and nitrogen species (RONS) are key characteristics of inflammatory sites. Scavenging RONS at the site of inflammation is an effective therapeutic strategy. This study introduces ultrasmall CuO@His nanoparticles with RONS-scavenging ability for the treatment of inflammatory bowel disease (IBD) in mice.

Construction of a colorimetric sensor array for the identification of phenolic compounds by the laccase-like activity of N-doped manganese oxide.

Phenolic compounds, widely distributed in nature, encompass a diverse array of bioactive and antioxidant properties. The detection of different phenolic compound types holds paramount importance in elucidating their bioactivity and health effects, ensuring the quality and safety of food and drugs. Consequently, the development of simple, rapid, and cost-effective colorimetric sensing arrays capable of simultaneous phenolic compound detection has emerged as a prominent research pursuit.

Self-template sacrifice and in situ oxidation of a constructed hollow MnO nanozymes for smartphone-assisted colorimetric detection of liver function biomarkers.

Liver function tests play a vital role in accurately diagnosing liver diseases, monitoring treatment outcomes, and assessing liver damage severity. Here, we introduce a novel approach to develop a smartphone-assisted portable colorimetric sensor for rapid detection of three liver function biomarkers: aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). This sensor is based on the inherent enzyme-like activities of hollow MnO (H-MnO).

Peroxidase-mimicking poly-L-lysine/alginate microspheres with PtS nanoparticles for image-based colorimetric assays.

Morphologically controllable ALG@ε-PL water-in-water microspheres were successfully prepared using a two-step method through precise control of the two-phase flow rate. Through further interfacial coagulation, the ALG@ε-PL microspheres possess a dense surface structure and good permeability. The sensor based on PtS@ALG@ε-PL microspheres was constructed by encapsulating PtS nanosheets with peroxidase-like properties in ALG@ε-PL water-in-water microspheres.

Fluorescent sensor based on PtS-PEG nanosheets with peroxidase-like activity for intracellular hydrogen peroxide detection and imaging.

Hydrogen peroxide (HO) is produced in living organisms and is involved in a variety of redox-regulated processes. Therefore, the detection of HO is important for tracing the molecular mechanisms of some biological events. Here, we demonstrated for the first time the peroxidase activity of PtS-PEG NSs under the physiological conditions.

Injectable and Self-Healing Hydrogel Based on Chitosan-Tannic Acid and Oxidized Hyaluronic Acid for Wound Healing.

Self-healing performance plays an important role in the in situ microinvasive injection of hydrogels, which can reduce sudden drug release and prolong the service life of hydrogels. In this paper, a multifunctional injectable and self-healing hydrogel for wound healing was developed. Chitosan (CS) was modified with TA to achieve potential adhesion, anti-inflammatory properties, and slower degradation rate.

PtS nanosheets as a peroxidase-mimicking nanozyme for colorimetric determination of hydrogen peroxide and glucose.

Using an ultrasonication-assisted liquid exfoliation method, we have synthesized PtS nanosheets with good reproducibility. Herein, intrinsic peroxidase-like activity was for the first time demonstrated for PtS nanosheets, which can catalyze HO oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to generate a colored solution. The catalytic mechanism of PtS nanosheets was investigated, which indicated that acceleration of the electron transfer between TMB and HO was the main reason for the peroxidase-like activity of PtS nanosheets.

Molecular design of peptide amphiphiles for controlled self-assembly and drug release.

Peptide amphiphile-based supramolecular hydrogels hold great promise in drug delivery applications. To cater for a specific drug dose in a demanding biomedical scenario, sophisticated design of peptide amphiphile (PA) molecules is required to tune their self-assembling behaviours as well as drug releasing profiles. Herein, we designed a series of PAs with various capping groups and C-terminal amino acids to systematically optimize their self-assembling capabilities for controlled drug release.

Instant Self-Assembly Peptide Hydrogel Encapsulation with Fibrous Alginate by Microfluidics for Infected Wound Healing.

Infected wounds caused by persistent inflammation exhibit poor vascularization and cellular infiltration. In order to rapidly control the inflammatory effect and accelerate wound healing, it is necessary to develop a novel drug vehicle addressing the need for infected wounds. Herein, we developed a novel dual-drug delivery system with micrometer-scale alginate fibers encapsulated in instant self-assembly peptide hydrogel.

Dopamine-functionalized hyaluronic acid microspheres for effective capture of CD44-overexpressing circulating tumor cells.

As one of the biomarkers of liquid biopsy, circulating tumor cells (CTCs) provides important clinical information for cancer diagnosis. However, accurate separation and identification of CTCs remains a great deal of challenge. In present work, we developed novel dopamine-functionalized hyaluronic acid microspheres (HA-DA microspheres) to capture CD44-overexpressing CTCs.

PEG-PtS nanosheet-based fluorescence biosensor for label-free human papillomavirus genotyping.

A simple and efficient ultrasonication-assisted liquid exfoliation method is proposed to produce PtS nanosheets on a large scale and improve their dispersion in aqueous solution by surface polyethylene glycol modification. The interaction of polyethylene glycol-modified PtS (PEG-PtS) nanosheets with fluorescent labeled DNA and the fluorescence quenching mechanism using FAM-labeled hpv16e6 gene fragment as a probe was investigated. The excitation and emission wavelengths were 468 and 517 nm, respectively.

A simply triggered peptide-based hydrogel as an injectable nanocarrier of tanshinone IIA and tanshinones.

An easily self-assembled and gelated octa-peptide FHFDFHFD was chosen as a novel drug delivery system (DDS) for both tanshinone IIA and total tanshinone extract. The DDS showed increased loading capacity, sustained drug release and better anticancer capability. Our research proved that a hydrogel DDS of other traditional Chinese medicines is possible.

Overcoming multidrug resistance by a combination of chemotherapy and photothermal therapy mediated by carbon nanohorns.

Multidrug resistance (MDR) is a major obstacle to cancer chemotherapy due to the overexpression of P-glycoprotein (P-gp). Herein, etoposide (ETO) was loaded onto oxidized carbon nanohorns (oxCNHs), which were modified by polyethylene glycol (PEG) and further functionalized with the targeting ligand P-gp monoclonal antibody (PA) in an attempt to overcome MDR. The obtained drug delivery system (ETO@oxCNHs/PEG-PA) showed high drug loading efficiency, enhanced drug release under laser irradiation, improved cellular uptake and increased therapeutic effect both in vitro and in vivo.

Monitoring the intracellular calcium response to a dynamic hypertonic environment.

The profiling of physiological response of cells to external stimuli at the single cell level is of importance. Traditional approaches to study cell responses are often limited by ensemble measurement, which is challenging to reveal the complex single cell behaviors under a dynamic environment. Here we report the development of a simple microfluidic device to investigate intracellular calcium response to dynamic hypertonic conditions at the single cell level in real-time.

Rapid determination of dopamine in human plasma using a gold nanoparticle-based dual-mode sensing system.

Dopamine plays a very important role in biological systems and has a direct relationship with the ability of learning and cognition, human desires, feelings and mental state, as well as motor functions. Traditional methods for the detection of dopamine are complicated and time-consuming, therefore it is necessary to explore rapid and accurate detection of dopamine with high sensitivity and specificity. Herein we report a dual-mode system of colorimetric and fluorometric analyses based on gold nanoparticles (AuNPs) and aptamers specifically targeting dopamine.

Microfluidic Platform for Studying Chemotaxis of Adhesive Cells Revealed a Gradient-Dependent Migration and Acceleration of Cancer Stem Cells.

Recent studies reveal that solid tumors consist of heterogeneous cells with distinct phenotypes and functions. However, it is unclear how different subtypes of cancer cells migrate under chemotaxis. Here, we developed a microfluidic device capable of generating multiple stable gradients, culturing cells on-chip, and monitoring single cell migratory behavior.

A microfluidic linear node array for the study of protein-ligand interactions.

We have developed a microfluidic device for the continuous separation of small molecules from a protein mixture and demonstrated its practical use in the study of protein-ligand binding, a crucial aspect in drug discovery. Our results demonstrated dose-dependent binding between bovine serum albumin (BSA) and its small-molecule site marker, Eosin Y (EY), and found that the binding reached a plateau when the BSA : EY ratio was above 1, which agreed with the eosin binding capacity of BSA reported in literature. By streamline control using a combination of two fundamental building blocks (R and L nodes) with a microdevice operated at a high flow rate (up to 1300 μL h(-1)), a solution barrier was created to "filter" off protein/protein-ligand complexes such that the small unbound molecules were isolated and quantified easily.

Single layer linear array of microbeads for multiplexed analysis of DNA and proteins.

In this study, a microfluidic platform was developed to generate single layer, linear array of microbeads for multiplexed high-throughput analysis of biomolecules. The microfluidic device is comprised of eight microbead-trapping units, where microbeads were immobilized in a linear array format by the exertion of a negative pressure in the control channel connected to each sieving microstructure. Multiplexed assays were achieved by using a mixture of different spectrally-encoded microbeads functionalized with specific probes, followed by on-chip reaction and detection.

Nanoparticle-based signal generation and amplification in microfluidic devices for bioanalysis.

Signal generation and amplification based on nanomaterials and microfluidic techniques have both attracted considerable attention separately due to the demands for ultrasensitive and high-throughput detection of biomolecules. This article reviews the latest development of signal amplification strategies based on nanoparticles for bioanalysis and their integration and applications in microfluidic systems. The applications of nanoparticles in bioanalysis were categorized based on the different approaches of signal amplification, and the microfluidic techniques were summarized based on cell analysis and biomolecule detection with a focus on the integration of nanoparticle-based amplification in microfluidic devices for ultrasensitive bioanalysis.

On-site formation of emulsions by controlled air plugs.

Air plugs are usually undesirable in microfluidic systems because of their detrimental effect on the system's stability and integrity. By controlling the wetting properties as well as the topographical geometry of the microchannel, it is reported herein that air plugs can be generated in pre-defined locations to function as a unique valve, allowing for the on-site formation of various emulsions including single-component droplets, composite droplets with droplet-to-droplet concentration gradient, blood droplets, paired droplets, as well as bubble arrays without the need for precious flow control, a difficult task with conventional droplet microfluidics. Moreover, the self-generated air valve can be readily deactivated (turned off) by the introduction of an oil phase, allowing for the on-demand release of as-formed droplets for downstream applications.

Microfluidics study of intracellular calcium response to mechanical stimulation on single suspension cells.

A microfluidic microdevice was developed to exert mechanical stimulation on an individual suspension cell for mechanosensation research. In this microfluidic chip, an individual cell was isolated from a population of cells, and trapped in a microchannel with a compressive component made of a deflectable membrane. The mechanosensation of HL60 cells (leukemic cells) was studied using this chip, and the results showed that mechanical stimulations could trigger extracellular calcium to flow into HL60 cells through ion channels on cell membranes.

Screen printing of solder resist as master substrates for fabrication of multi-level microfluidic channels and flask-shaped microstructures for cell-based applications.

Although silicon technology can be adopted for the fabrication of microfluidic devices with high precision, the capital and operating costs for such technology is often prohibitively expensive. In recent years, many alternative methods have been advocated to reduce the cost of microfabrication but often with reduced qualities in many important features, such as channel resolution, surface smoothness and aspect ratio. In this study, we have developed a microfabrication method that retains high channel quality and aspect ratio by exploring a rarely used solder resist material in combination with screen printing technique to generate masters where PDMS-based microfluidic devices could be fabricated by replica molding from the masters.

Integrated sieving microstructures on microchannels for biological cell trapping and droplet formation.

We have developed a single step microfabrication method to prepare constriction microstructures on a PCB master by controlling the etching time of two microchannels separated by a finite distance that is easily attainable using imagesetters widely available in the printing industry. PDMS replica of the constriction structures present sieving microstructures (microsieves) that could be used for size-dependent trapping of microspheres, biological cells and the formation of water-in-oil droplets.