A Biomarker-Responsive Nanosystem with Colon-Targeted Delivery for Ulcerative Colitis's Detection and Treatment with Optoacoustic/NIR-II Fluorescence Imaging

Injectable-Hydrogel-Based Tissue Sealant for Hemostasis, Bacteria Inhibition, and Pro-Angiogenesis in Organ Bleeding Wounds and Therapeutic Outcome Monitoring Via NIR-II Optical Imaging

Sudden hemorrhage stemming from internal organ wounds poses a grave and potentially fatal risk if left untreated. Injectable-hydrogel-based tissue sealants featuring multiple actions, including fit-to-shape in situ gelation, rapid hemostasis, pro-angiogenic, anti-bacterial and outcome tracking, are ideal for the management of organ trauma wounds. Herein, an injectable-hydrogel tissue sealant AN@CD-PEG&TQ which consists of four-arm 4-arm poly(ethylene glycol) (PEG-SC) succinimidyl carbonate), AN@CD nanoprobe, and two bioactive peptides (anti-microbial peptide Tet213 and pro-angiogenic peptide QK) is developed. Among them, AN@CD nanoparticles form through host/guest complexation of amino-group-containing β-cyclodextrin and adamantyl group, enabling in situ biomarker (NO)-activatable optoacoustic/NIR-II: Near-infrared second biological window fluorescent imaging. The ample ─NH2 groups on the surface of AN@CD readily engage in rapid cross-linking with succinimidyl ester groups located at the ends of four-arm PEG-SC. This cross-linking expedites the gelation process without necessitating additional initiators or cross-linking agents; thus, significantly enhancing both hydrogel's application convenience and biocompatibility. Bioactive peptides (Tet213 and QK) safeguard against possible bacterial infections, facilitate angiogenesis, and eventually, improve organ wounds healing. This hydrogel-based tissue sealant demonstrates superior therapeutic and bioimaging performance in various mouse models including liver hemorrhage, gastric perforation, and bacterial-infected skin wound mouse models, highlighting its potential as a high-performance wound sealant for organ bleeding wound management.

Homo-Dyad with Outer Hydration Layer Approach for Developing NIR-II Chromophore of High Stability and Water-Solubility as Injectable and Sprayable Optical Probe

Dyes with extended conjugate structures are the focus of extensive design and synthesis efforts, aiming to confer unique and improved optical and electronic properties. Such advancements render these dyes applicable across a wide spectrum of uses, ranging from second-window near-infrared (NIR-II) bioimaging to organic photovoltaics. Nevertheless, the inherent benefits of long conjugation are often accompanied by persistent challenges like aggregation, fluorescence quenching, absorption blueshift, and low stability and poor water solubility. Herein, a unique structural design strategy termed "homo-dyad with outer hydration layer" is introduced to address these inherent problems, tailored for the development of imaging probes exhibiting long absorption/emission wavelengths. This approach involves bringing two heptamethine cyanines together through a flexible linker, forming a homo-dyad structure, while strategically attaching four polyethylene glycol (PEG9) chains to the terminal heterocycles. This approach imparts excellent water solubility, biocompatibility, and enhanced chemical, photo-, and spectral stability for the dyes. Utilizing this strategy, a biomarker-activatable probe (HD-FL-4PEG9-N) for NIR-II fluorescent and 3D multispectral optoacoustic tomography imaging is developed, and its effectiveness in disease visualization. It can not only serve as an injectable probe for acute kidney injury imaging due to its high water solubility, but also a sprayable probe for imaging bacterial-infected wounds.

Nanotechnology's frontier in combatting infectious and inflammatory diseases: prevention and treatment

Inflammation-associated diseases encompass a range of infectious diseases and non-infectious inflammatory diseases, which continuously pose one of the most serious threats to human health, attributed to factors such as the emergence of new pathogens, increasing drug resistance, changes in living environments and lifestyles, and the aging population. Despite rapid advancements in mechanistic research and drug development for these diseases, current treatments often have limited efficacy and notable side effects, necessitating the development of more effective and targeted anti-inflammatory therapies. In recent years, the rapid development of nanotechnology has provided crucial technological support for the prevention, treatment, and detection of inflammation-associated diseases. Various types of nanoparticles (NPs) play significant roles, serving as vaccine vehicles to enhance immunogenicity and as drug carriers to improve targeting and bioavailability. NPs can also directly combat pathogens and inflammation. In addition, nanotechnology has facilitated the development of biosensors for pathogen detection and imaging techniques for inflammatory diseases. This review categorizes and characterizes different types of NPs, summarizes their applications in the prevention, treatment, and detection of infectious and inflammatory diseases. It also discusses the challenges associated with clinical translation in this field and explores the latest developments and prospects. In conclusion, nanotechnology opens up new possibilities for the comprehensive management of infectious and inflammatory diseases.

Development of a Novel ATP Bioluminescence Assay Based on Engineered Probiotic Saccharomyces boulardii Expressing Firefly Luciferase

Quantitative analysis of adenosine triphosphate (ATP) has been widely used as a diagnostic tool in the food and medical industries. Particularly, the pathogenesis of a few diseases including inflammatory bowel disease (IBD) is closely related to high ATP concentrations. A bioluminescent D-luciferin/luciferase system, which includes a luciferase (FLuc) from the firefly Photinus pyralis as a key component, is the most commonly used method for the detection and quantification of ATP. Here, instead of isolating FLuc produced in recombinant Escherichia coli, we aimed to develop a whole-cell biocatalyst system that does not require extraction and purification of FLuc. To this end, the gene coding for FLuc was introduced into the genome of probiotic Saccharomyces boulardii using the CRISPR/Cas9-based genome editing system. The linear relationship (r2 = 0.9561) between ATP levels and bioluminescence generated from the engineered S. boulardii expressing FLuc was observed in vitro. To explore the feasibility of using the engineered S. boulardii expressing FLuc as a whole-cell biosensor to detect inflammation biomarker (i.e., ATP) in the gut, a colitis mouse model was established using dextran sodium sulfate as a colitogenic compound. Our findings demonstrated that the whole-cell biosensor can detect elevated ATP levels during gut inflammation in mice. Therefore, the simple and powerful method developed herein could be applied for non-invasive IBD diagnosis.

Recent advances on emerging nanomaterials for diagnosis and treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic idiopathic inflammatory disorder that affects the entire gastrointestinal tract and is associated with an increased risk of colorectal cancer. Mainstream clinical testing methods are time-consuming, painful for patients, and insufficiently sensitive to detect early symptoms. Currently, there is no definitive cure for IBD, and frequent doses of medications with potentially severe side effects may affect patient response. In recent years, nanomaterials have demonstrated considerable potential for IBD management due to their diverse structures, composition, and physical and chemical properties. In this review, we provide an overview of the advances in nanomaterial-based diagnosis and treatment of IBD in recent five years. Multi-functional bio-nano platforms, including contrast agents, near-infrared (NIR) fluorescent probes, and bioactive substance detection agents have been developed for IBD diagnosis. Based on a series of pathogenic characteristics of IBD, the therapeutic strategies of antioxidant, anti-inflammatory, and intestinal microbiome regulation of IBD based on nanomaterials are systematically introduced. Finally, the future challenges and prospects in this field are presented to facilitate the development of diagnosis and treatment of IBD.

Oral Delivery of Transformable Bilirubin Self-Assembled System for Targeted Therapy of Colitis

Ulcerative colitis (UC) is a high incidence disease worldwide and clinically presents as relapsing and incurable inflammation of the colon. Bilirubin (BR), a natural antioxidant with significant anti-colitic effects, is utilized in preclinical studies as an intestinal disease therapy. Due to their water-insolubility, the design of BR-based agents usually involves complicated chemosynthetic processes, introducing various uncertainties in BR development. After screening numerous materials, it is identified that chondroitin sulfate can efficiently mediate the construction of BR self-assembled nanomedicine (BSNM) via intermolecular hydrogen bonds between dense sulfate and carboxyl of chondroitin sulfate and imino groups of BR. BSNM exhibits pH sensitivity and reactive oxygen species responsiveness, enabling targeted delivery to the colon. After oral administration, BSNM significantly inhibits colonic fibrosis and apoptosis of colon and goblet cells; it also reduces the expression of inflammatory cytokines. Moreover, BSNM maintains the normal level of zonula occludens-1 and occludin to sustain the integrity of intestinal barrier, regulates the macrophage polarization from M1 to M2 type, and promotes the ecological recovery of intestinal flora. Collectively, the work provides a colon-targeted and transformable BSNM that is simple to prepare and is useful as an efficient targeted UC therapy.

Renal-Clearable Probe with Water Solubility and Photostability for Biomarker-Activatable Detection of Acute Kidney Injuries via NIR-II Fluorescence and Optoacoustic Imaging

Acute kidney injuries (AKI) have serious short-term or long-term complications with high morbidity and mortality rate, thus posing great health threats. Developing high-performance NIR-II probes for noninvasive in situ detection of AKI via NIR-II fluorescent and optoacoustic dual-mode imaging is of great significance. Yet NIR-II chromophores often feature long conjugation and hydrophobicity, which prevent them from being renal clearable, thus limiting their applications in the detection and imaging of kidney diseases. To fully exploit the advantageous features of heptamethine cyanine dye, while overcoming its relatively poor photostability, and to strive to design a NIR-II probe for the detection and imaging of AKI with dual-mode imaging, herein, we have developed the probe PEG3-HC-PB, which is renal clearable, water soluble, and biomarker activatable and has good photostability. As for the probe, its fluorescence (900-1200 nm) is quenched due to the existence of the electron-pulling phenylboronic group (responsive element), and it exhibits weak absorption with a peak at 830 nm. Meanwhile, in the presence of the overexpressed H₂O₂ in the renal region in the case of AKI, the phenylboronic group is converted to the phenylhydroxy group, which enhances NIR-II fluorescent emission (900-1200 nm) and absorption (600-900 nm) and eventually produces conspicuous optoacoustic signals and NIR-II fluorescent emission for imaging. This probe enables detection of contrast-agent-induced and ischemia/reperfusion-induced AKI in mice using real-time 3D-MSOT and NIR-II fluorescent dual-mode imaging via response to the biomarker H₂O₂. Hence, this probe can be used as a practicable tool for detecting AKI; additionally, its design strategy could provide insight into the design of other large-conjugation NIR-II probes with multifarious biological applications.