Rapid and facile electrospray preparation of CsPbBr3@PMMA fluorescent microspheres for fluorescent detection of ALP in biological samples

The carrier dynamics for self-assembled black phosphorus and perovskite nanocrystals enable photocatalytic conversion

Few-layer black phosphorus (BP) becomes an ideal self-assembled material with perovskite nanocrystals (NCs) for photoluminescence (PL) and photocatalysis, due to the feasible control of photogenerated charge carriers. Until now, it is still a challenge to figure out the intrinsic carrier dynamics for multifunctional photodegradation in water. In this work, a series of few-layer BP components were successfully incorporated into CsPbBr3 NCs to achieve apparent PL quenching and ˙O2--dominated photocatalytic degradation of rhodamine B in aqueous solution. The strategy of BP modification can extend photoabsorption ensuring optimized photocatalytic activity by facilitating electron transfer from CsPbBr3 to BP with strong van der Waals interactions. In particular, CsPbBr3:5%BP NC eliminates the effect of sub-bandgap luminescence centers, resulting in a low charge transfer resistance, good carrier mobility, and high photocurrent densities under light irradiation.

Self-Assembled DNA/SG-I Nanoflower: Versatile Photocatalytic Biosensors for Disease-Related Markers

DNA nanostructures have recently attracted more attention with functionalities, programmability, and biocompatibility. Herein, a novel self-assembled photocatalytic DNA/SYBR Green I (SG-I) nanoflower (DSNF) was successfully synthesized by rolling circle amplification. DSNF was self-assembled through liquid crystallization of a high concentration of DNA in the RCA products, without relying on the Watson-Crick base-pairing principle. Interestingly, DSNF not only possessed a larger specific surface area and good stability but also exhibited excellent photocatalytic activity that generates singlet oxygen and superoxide anion to oxidate 3,3',5,5'-tetramethylbenzidine. Meanwhile, the photocatalytic DSNF combined with an enzyme-linked immunosorbent assay to develop a new colorimetric sensor for highly specific, sensitive, and visual detection of carcinoembryonic antigens (CEAs). The colorimetric sensor achieved sensitive and low-cost quantitative detection of CEA in the linear range of 0.5-80.0 ng/mL, and the LOD was 0.5 ng/mL. In addition, three negative and seven positive clinical serum samples of CEA were obtained with 100% accuracy using the proposed colorimetric sensor, showing great potential in the clinical application of cancer diagnosis. We envision that this photocatalytic DSNF is expected to provide important perspectives in fluorescence imaging, photosensitizing cancer therapy, and clinical diagnosis fields.

Recent Advances and Challenges in Metal Halide Perovskite Quantum Dot-Embedded Hydrogels for Biomedical Application

Metal halide perovskite quantum dots (MHP QDs), as a kind of fluorescent material, have attracted much attention due to their excellent photoluminescence (PL) quantum yield (QY), narrow full width at half maximum (FWHM), broad absorption, and tunable emission wavelength. However, the instability and biological incompatibility of MHP QDs greatly hinder their application in the field of biomedicine. Hydrogels are three-dimensional polymer networks that are widely used in biomedicine because of their high transparency and excellent biocompatibility. This review not only introduces the latest research progress in improving the mechanical and optical properties of hydrogels/MHP QDs but also combines it with the existing methods for enhancing the stability of MHP QDs in hydrogels, aiming to provide new ideas for researchers in material selection and methods for constructing MHP QD-embedded hydrogels. Finally, their application prospects and future challenges are introduced.

A point-of-care solid-phase colorimetric sensor based on the enzyme-induced metallization for ALP detection

Alkaline phosphatase (ALP) is a crucial biomarker for clinical diagnosis, which is closely related to the physiological homeostasis regulation process of human body. And the abnormal level of ALP is associated with numerous diseases, such as liver dysfunction, bone diseases, diabetes, and so on. In order to meet the demand of personalized healthcare, it is particularly important to develop a miniaturized point-of-care testing (POCT) device for ALP detection. Herein, a portable solid-phase colorimetric sensor based on enzyme-induced metallization signal amplification strategy was constructed for ALP detection. The AuNPs modified on the glass slides acted as crystal seeds, allowing Ag+ in the solution to be reduced and deposited on the surface of AuNPs, which further formed the gold core and silver shell (Au@Ag) complex and generated visual signals. The visual signals were recorded by a smartphone and quantified using open-source ImageJ software. Under the optimal conditions, the proposed method exhibited a good linear relationship from 2.0 to 16.0 pM, and the detection limit was as low as 0.9 pM. In addition, it was further successfully applied for ALP detection in non-transparent and complex samples (milk, different types of cells). A sensitive, low cost, rapid and convenient solid-phase sensor was developed for ALP detection, which was expected to provide a promising strategy for POCT devices.

Construction of Metal Organic Framework-Derived Fe-N-C Oxidase Nanozyme for Rapid and Sensitive Detection of Alkaline Phosphatase

Alkaline phosphatase (ALP) is a phosphomonoester hydrolase and serves as a biomarker in various diseases. However, current detection methods for ALP rely on bulky instruments, extended time, and complex operations, which are particularly challenging in resource-limited regions. Herein, we synthesized a MOF-derived Fe-N-C nanozyme to create biosensors for the coulometric and visual detection of ALP. Specifically, we found the Fe-N-C nanozyme can efficiently oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to generate blue-colored tetramethyl benzidine (TMBox) without the need for H2O2. To construct the biosensor, we incorporated the ALP enzymatic catalytic reaction to inhibit the oxidation of TMB by Fe-N-C oxidase nanozyme. This biosensor showed rapid and highly sensitive detection of ALP in both buffer and clinical samples. The limit of detection (LOD) of our approach could be achieved at 3.38 U L-1, and the linear range was from 5 to 60 U L-1. Moreover, we also developed a visual detection for ALP by using a smartphone-based assay and facilitated practical and accessible point-and-care testing (POCT) in resource-limited areas. The visual detection method also achieved a similar LOD of 2.12 U L-1 and a linear range of 5-60 U L-1. Our approach presents potential applications for other biomarker detections by using ALP-based ELISA methods.

Homogenous multifunctional microspheres induce ferroptosis to promote the anti-hepatocarcinoma effect of chemoembolization

Transcatheter arterial chemoembolization (TACE) is one of the main palliative therapies for advanced hepatocellular carcinoma (HCC), which is also regarded as a promising therapeutic strategy for cancer treatment. However, drug-loaded microspheres (DLMs), as commonly used clinical chemoembolization drugs, still have the problems of uneven particle size and unstable therapeutic efficacy. Herein, gelatin was used as the wall material of the microspheres, and homogenous gelatin microspheres co-loaded with adriamycin and Fe₃O₄ nanoparticles (ADM/Fe₃O₄-MS) were further prepared by a high-voltage electrospray technology. The introduction of Fe₃O₄ nanoparticles into DLMs not only provided excellent T2-weighted magnetic resonance imaging (MRI) properties, but also improved the anti-tumor effectiveness under microwave-induced hyperthermia. The results showed that ADM/Fe₃O₄-MS plus microwave irradiation had significantly better antitumor efficacy than the other types of microspheres at both cell and animal levels. Our study further confirmed that ferroptosis was involved in the anti-tumor process of ADM/Fe₃O₄-MS plus microwave irradiation, and ferroptosis marker GPX4 was significantly decreased and ACSL4 was significantly increased, and ferroptosis inhibitors could reverse the tumor cell killing effect caused by ADM/Fe₃O₄-MS to a certain extent. Our results confirmed that microwave mediated hyperthermia could amplify the antitumor efficacy of ADM/Fe₃O₄-MS by activating ferroptosis and the introduction of Fe₃O₄ nanoparticles can significantly improve TACE for HCC. This study confirmed that it was feasible to use uniform-sized gelatin microspheres co-loaded with Fe₃O₄ nanoparticles and adriamycin to enhance the efficacy of TACE for HCC.