Hydrogels exhibit excellent moldability, biodegradability, biocompatibility, and extracellular matrix-like properties, which make them widely used in biomedical fields. Because of their unique three-dimensional crosslinked hydrophilic networks, hydrogels can encapsulate various materials, such as small molecules, polymers, and particles; this has become a hot research topic in the antibacterial field. The surface modification of biomaterials by using antibacterial hydrogels as coatings contributes to the biomaterial activity and offers wide prospects for development. A variety of surface chemical strategies have been developed to bind hydrogels to the substrate surface stably. We first introduce the preparation method for antibacterial coatings in this review, which includes surface-initiated graft crosslinking polymerization, anchoring the hydrogel coating to the substrate surface, and the LbL self-assembly technique to coat crosslinked hydrogels. Then, we summarize the applications of hydrogel coating in the biomedical antibacterial field. Hydrogel itself has certain antibacterial properties, but the antibacterial effect is not sufficient. In recent research, in order to optimize its antibacterial performance, the following three antibacterial strategies are mainly adopted: bacterial repellent and inhibition, contact surface killing of bacteria, and release of antibacterial agents. We systematically introduce the antibacterial mechanism of each strategy. The review aims to provide reference for the further development and application of hydrogel coatings.

This study synthesized graphene oxide (GO)/zinc oxide (ZnO)/silver (Ag) composite materials and investigated their photocatalytic degradation performance for ciprofloxacin (CIP) under visible light irradiation. GO/ZnO/Ag composites with different ratios were prepared via an impregnation and chemical reduction method and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The results demonstrated that under optimal conditions (20 mg/L CIP concentration, 15 mg catalyst dosage, GO/ZnO-3%/Ag-doping ratio, and pH 5), the GO/ZnO/Ag composite exhibited the highest photocatalytic activity, achieving a maximum degradation rate of 82.13%. This catalyst effectively degraded ciprofloxacin under light irradiation, showing promising potential for water purification applications.

A copper-based nanoenzyme (Cu-BL) co-modified by L-L-lysine and 2-2-amino terephthalic acid has laccase-like activity and fluorescence characteristics. Based on this, a colorimetric and fluorescent dual-mode sensor was developed to visually and quantitatively detect tetracycline antibiotics (TCs), including tetracycline (TC), chlortetracycline (CTC), and oxytetracycline (OTC). In the colorimetric detection system, TCs can inhibit the generation of singlet oxygen (¹O₂) and weaken the ability of 2,4-dichlorophenol (2,4-DP) to be oxidized into pink-colored quinone substances. The linear ranges are 0.5–80 μM, 1–80 μM, and 0.25–80 μM, and the detection limits are 0.27 μM, 0.22 μM, and 0.26μM, respectively. In addition, due to the inner filter effect, tetracycline antibiotics can interact with Cu-BL, and with the increase in tetracycline antibiotic concentration, the fluorescence intensity will decrease. In addition, the smartphone sensing platform is combined with the colorimetric signal for the rapid and visual quantitative detection of tetracycline antibiotics. Generally speaking, the colorimetric/fluorescence dual-mode sensor demonstrates good stability, high specificity, and strong anti-interference capabilities, highlighting its practical application potential. This work is expected to offer novel insights for the development of multifunctional nanoenzymes and the integration of a multi-mode sensing platform.

Due to their unique photocatalytic properties, nanostructured photocatalysts have shown broad prospects for application in environmental treatment. In recent years, researchers have significantly enhanced the photocatalytic charge separation efficiency and photocatalytic stability of photocatalysts by regulating semiconductor energy band structures, optimizing interface and surface properties, constructing heterogeneous structures, and introducing noble metal doping. This review systematically summarizes the basic principles, synthesis methods, and modification strategies of nanostructured photocatalysts and focuses on recent research advances in their environmental applications, such as water pollution control, air purification, and carbon dioxide reduction. Meanwhile, this review analyzes current challenges in the field, such as low quantum efficiency, insufficient stability, and limited industrialization, and outlines future development directions, including smart catalytic technology, fabrication of multifunctional composites, and large-scale synthesis, thereby providing a reference for research and application.

With the unprecedented progress of biomedical nanotechnology in the past few decades, traditional drug delivery systems (DDSs) have been incorporated into intelligent DDSs with stimulus responsive characteristics. Graphene oxide (GO) and Chitosan (CS) have excellent physical, chemical, mechanical, and optical properties, and their synergistic effects have attracted widespread attention in the biomedical field. In this review, we focus on the physicochemical characteristics of GO, CS, and GO/CS composites, as well as the research progress of DDS types based on GO/CS.

To reduce the risk of infection, improving the anti-infection ability of Ti-based implantation has become a very meaningful task. In this work, by employing polydopamine (PDA) as a carrier and curcumin (CUR) as an anti-biotic/inflammatory, a series of Ti-PDA@CURx (x = 0.5, 1.0, 1.5, 2.0, 2.5) was successfully fabricated and characterized by scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy, and the water contact angle, where Ti plates were firmly coated by PDA@CUR. The test result of CUR content shows that the maximum loading of CUR in PDA can reach 0.6506%, where the CUR concentration is 1.5 mg/mL. The antibacterial test results demonstrate that Ti-PDA@CUR-x (x = 0.5, 1.0, 1.5, 2.0, 2.5) exhibit significant antibacterial activities against Escherichia coli and S. aureu, where Ti-PDA@CUR1.5 has the highest antibacterial rate of 62.7% against Escherichia coli and 52.6% against S. aureus. The cytotoxicity test shows that Ti-PDA, Ti-PDA@CUR-x (x = 0.5, 1.0, 1.5, 2.0, 2.5) has almost no toxicity.