Simultaneous inhibition of planktonic and biofilm bacteria by self-adapting semiconducting polymer dots

Dopamine-assisted surface functionalization of saccharide-responsive fibers for the controlled harvesting and continuous fermentation of Saccharomyces cerevisiae

Continuous fermentation processes increasingly emphasized cell recycling, utilization, and renewal. In this study, to improve the sustainability of the immobilized Saccharomyces cerevisiae, the cells were recovered on the surface of the glucose-responsive supports through manipulating the competitive interactions of phenylboric acid groups between glycoproteins on the cells and glucose. Through a dopamine (DA)-assisted deposition approach, 3-acrylamidophenylboronic acid (APBA) was integrated to design the saccharide-sensitive cotton fibers (APBA@PDA-CF). The optimal co-deposition time (5 h) and ratio (1:1) resulted in an impressive immobilization efficiency of 69.64%. Meanwhile, 93.23% of Saccharomyces cerevisiae was captured and harvested on the surface of APBA@PDA-CF with the fermentation course through regulating the competitive interactions of phenylboric acid groups between glycoproteins on the cells and glucose regardless of pH. Notably, a strong interaction between the yeast cells and APBA@PDA-CF was observed at a low glucose concentration (0.1～2 g/L), with reduced sensitivity at high glucose concentrations (>5 g/L). Moreover, the ethanol production and yield could be increased to 25.37 g/L and 42.4% in the fifth-batch fermentation, respectively. Therefore, based on the feasible and versatile co-deposition method, this study not only broadened the application scope of APBA, but also explored the broad prospects of smart materials in cell immobilization, recovery and continuous fermentation.

Semiconducting polymer dots for multifunctional integrated nanomedicine carriers

The expansion applications of semiconducting polymer dots (Pdots) among optical nanomaterial field have long posed a challenge for researchers, promoting their intelligent application in multifunctional nano-imaging systems and integrated nanomedicine carriers for diagnosis and treatment. Despite notable progress, several inadequacies still persist in the field of Pdots, including the development of simplified near-infrared (NIR) optical nanoprobes, elucidation of their inherent biological behavior, and integration of information processing and nanotechnology into biomedical applications. This review aims to comprehensively elucidate the current status of Pdots as a classical nanophotonic material by discussing its advantages and limitations in terms of biocompatibility, adaptability to microenvironments in vivo, etc. Multifunctional integration and surface chemistry play crucial roles in realizing the intelligent application of Pdots. Information visualization based on their optical and physicochemical properties is pivotal for achieving detection, sensing, and labeling probes. Therefore, we have refined the underlying mechanisms and constructed multiple comprehensive original mechanism summaries to establish a benchmark. Additionally, we have explored the cross-linking interactions between Pdots and nanomedicine, potential yet complete biological metabolic pathways, future research directions, and innovative solutions for integrating diagnosis and treatment strategies. This review presents the possible expectations and valuable insights for advancing Pdots, specifically from chemical, medical, and photophysical practitioners' standpoints.

Biofilm microenvironment triggered self-enhancing photodynamic immunomodulatory microneedle for diabetic wound therapy

The treatment of diabetic wounds faces enormous challenges due to complex wound environments, such as infected biofilms, excessive inflammation, and impaired angiogenesis. The critical role of the microenvironment in the chronic diabetic wounds has not been addressed for therapeutic development. Herein, we develop a microneedle (MN) bandage functionalized with dopamine-coated hybrid nanoparticles containing selenium and chlorin e6 (SeC@PA), which is capable of the dual-directional regulation of reactive species (RS) generation, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), in response to the wound microenvironment. The SeC@PA MN bandage can disrupt barriers in wound coverings for efficient SeC@PA delivery. SeC@PA not only depletes endogenous glutathione (GSH) to enhance the anti-biofilm effect of RS, but also degrades GSH in biofilms through cascade reactions to generate more lethal RS for biofilm eradication. SeC@PA acts as an RS scavenger in wound beds with low GSH levels, exerting an anti-inflammatory effect. SeC@PA also promotes the M2-phenotype polarization of macrophages, accelerating wound healing. This self-enhanced, catabolic and dynamic therapy, activated by the wound microenvironment, provides an approach for treating chronic wounds.

Recent Advances of NIR-II Emissive Semiconducting Polymer Dots for In Vivo Tumor Fluorescence Imaging and Theranostics

Accurate diagnosis and treatment of tumors, one of the top global health problems, has always been the research focus of scientists and doctors. Near-infrared (NIR) emissive semiconducting polymers dots (Pdots) have demonstrated bright prospects in field of in vivo tumor fluorescence imaging owing to some of their intrinsic advantages, including good water-dispersibility, facile surface-functionalization, easily tunable optical properties, and good biocompatibility. During recent years, much effort has been devoted to developing Pdots with emission bands located in the second near-infrared (NIR-II, 1000-1700 nm) region, which hold great advantages of higher spatial resolution, better signal-to-background ratios (SBR), and deeper tissue penetration for solid-tumor imaging in comparison with the visible region (400-680 nm) and the first near-infrared (NIR-I, 680-900 nm) window, by virtue of the reduced tissue autofluorescence, minimal photon scattering, and low photon absorption. In this review, we mainly summarize the latest advances of NIR-II emissive semiconducting Pdots for in vivo tumor fluorescence imaging, including molecular engineering to improve the fluorescence quantum yields and surface functionalization to elevate the tumor-targeting capability. We also present several NIR-II theranostic Pdots used for integrated tumor fluorescence diagnosis and photothermal/photodynamic therapy. Finally, we give our perspectives on future developments in this field.

β-Lactamase-Responsive Probe for Efficient Photodynamic Therapy of Drug-Resistant Bacterial Infection

Several photosensitizers have recently been proposed as novel approaches against β-lactamase-producing drug-resistant bacteria. However, these reported photosensitizers are rarely used for accurate recognition of drug-resistant bacteria. To tackle this challenge, the structurally modified photosensitizer CySG-2 based on a lipophilic cationic heptamethine indocyanine near-infrared (NIR) dye (IR-780) and an important synthesis intermediate of cephalosporin antibiotic (GCLE) not only achieved the accurate recognition of TEM-1 methicillin-resistant Staphylococcus aureus (MRSA) successfully but also achieved antimicrobial photodynamic therapy (aPDT) in animal models infected by drug-resistant bacteria. Accurate enzyme recognition and efficient photodynamic therapy capabilities allow CySG-2 to achieve one stone with two birds. In addition, CySG-2 could also promote the eradication of internalized MRSA by facilitating the autophagy process, which is synergistic with its capacity of inducing reactive oxygen species generation under NIR laser irradiation for aPDT. Collectively, it is an effective multifunctional photosensitizer with the potential ability to guide the optimal use of different antibiotics and apply them in clinical treatment.

Water-soluble branched polymer for combined chemo-immunotherapy of bacterial infections

Bacterial infection is one of the most significant public health challenges due to the limited choices of antibiotics which can overcome antibiotic-resistant bacteria. The promising nonantibiotic therapeutic alternatives for antibiotic-resistant bacterial infection are urgently needed to reduce the disease burden. Herein, the water-soluble branched poly(amino ester) with inherently antibacterial (chemotherapy) and enhanced inflammatory response activity (immunotherapy) was prepared via Michael addition polymerization to combat bacterial infection. These polymers can not only damage bacteria walls, leading to the death of bacteria but also activate macrophages to low-output nitric oxide (NO), TNF-α and interleukin (IL)-1β to kill and clean bacteria. Importantly, these polymers can efficiently inhibit aminoglycoside-resistant P. aeruginosa even at a low dose of 500 nmol L^-1. Furthermore, these polymers can treat subcutaneous bacterial infections in vivo. In this study, we first report a water-soluble branched polymer to combat bacteria through the combination of chemotherapy and immunotherapy, which will open a new path to design promising potential therapeutic alternatives for bacterial infection.