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Antimicrobial phototherapy has gained recognition as a promising approach for addressing bacterial biofilms, however, its effectiveness is often impeded by the robust physical and chemical defenses of the biofilms. Traditional antibacterial nanoplatforms face challenges in breaching the extracellular polymeric substances barrier to efficiently deliver photosensitizers deep into biofilms. Moreover, the prevalent hypoxia within biofilms restricts the success of oxygen-reliant phototherapy. In this study, we engineered a soft mesoporous organosilica nanoplatform (SMONs) by incorporating polyethylene glycol (PEG), catalase (CAT), and indocyanine green (ICG), forming SMONs-PEG-CAT-ICG (SPCI). We compared the antimicrobial efficacy of SPCI with more rigid nanoplatforms. Our results demonstrated that unique flexible mechanical properties of SPCI enable it to navigate through biofilm barriers, markedly enhancing ICG penetration in methicillin-resistant Staphylococcus aureus (MRSA) biofilms. Notably, in a murine subcutaneous MRSA biofilm infection model, SPCI showed superior biofilm penetration and pharmacokinetic benefits over its rigid counterparts. The embedded catalase in SPCI effectively converts excess H 2 O 2 present in infected tissues into O 2 , alleviating hypoxia and significantly boosting the antibacterial performance of phototherapy. Both in vitro and in vivo experiments confirmed that SPCI surpasses traditional rigid nanoplatforms in overcoming biofilm barriers, offering improved treatment outcomes for infections associated with bacterial biofilms. This study presents a viable strategy for managing bacterial biofilm-induced diseases by leveraging the unique attributes of a soft mesoporous organosilica-based nanoplatform. This research introduces an innovative antimicrobial phototherapy soft nanoplatform that overcomes the inherent limitations posed by the protective barriers of bacterial biofilms. By soft nanoplatform with flexible mechanical properties, we enhance the penetration and delivery of photosensitizers into biofilms. The inclusion of catalase within this soft nanoplatform addresses the hypoxia in biofilms by converting hydrogen peroxide into oxygen in infected tissues, thereby amplifying the antibacterial effectiveness of phototherapy. Compared to traditional rigid nanoplatforms, this flexible nanoplatform not only promotes the delivery of therapeutic agents but also sets a new direction for treating bacterial biofilm infections, offering significant implications for future antimicrobial therapies. [Display omitted] [ABSTRACT FROM AUTHOR]

The interdisciplinary integration among material science, nanotechnology and biology has been promoting the emergences of a large number of feasible nanoplatforms for diverse biomedical applications. Thanks to the unique mesoporous structure, large specific surface area, abundant surface chemistry and tunable framework composition, mesoporous silica nanoparticles (MSNs) and mesoporous organosilica nanoparticles (MONs) have been extensively applied for diverse therapeutic, or diagnostic applications. The past two decades have witnessed the blooming growth of researches on the elaborate design and fabrication of multifunctional MSNs/MONs-based nanosystems, which have greatly pushed forward the development of next-generation theranostic biomaterials. These mesoporous silica-based nanomaterials feature varied structural, compositional and morphological characteristics, leading to the great diversity in their downstream physicochemical properties and theranostic performances, which further catalyzes the emergence of advanced therapeutic strategies for optimized treatment efficacies and mitigated side effects. In this review, we will comprehensively elucidate very-recent advances on the construction of MSNs/MONs-based theranostic nanoplatforms for various therapeutic and diagnostic applications, and discuss the underlying material chemistry of these exquisite nanosystems that confers varied theranostic functionalities. Especially, the interdependent relationship among the synthesis, biological effects and biomedical applications of MSNs and MONs will be discussed in depth, and their further clinical-translation potential/challenge will be clarified and outlooked. It is highly expected that we will witness a second leap-forward development of the biomedical applications of MSNs and MONs in the next one or two decades, especially for the further clinical translation. [ABSTRACT FROM AUTHOR]

Citronellol (CI)-loaded, chitosan (CS)-enclosed dendritic mesoporous organosilica nanoparticles (CI@D-MONs@CS) are successfully fabricated. The synthesized CI@D-MONs@CS present spherical shape with the particle size of 424±24 nm in diameter and dendritic mesopores. CI loading ratio of CI@D-MONs@CS is about 12.42% from TGA analysis. CI release from CI@D-MONs@CS exhibits pH-redox dual responsiveness. More interesting, the axillary deodorant effect is investigated with Staphylococcus haemolyticus in an artificial sweat model. The results show that CI@D-MONs@CS present an excellent bacteria-killing effect and the smell of artificial sweat is greatly improved, avoiding the formation of undesirable odorant compounds from the bacteria. The obtained CI@D-MONs@CS is a potential carrier of natural fragrance or actives with dual responsive release. The application of CI@D-MONs@CS is a new and effective strategy to the axillary odor problem. • The pH-redox dual responsive nanoparticles CI@D-MONs@CS were designed and fabricated. • Chitosan formed the pH-responsive "gate" of CI@D-MONs@CS. • CI@D-MONs@CS exhibited significantly enhanced and durable antibacterial capacities. • CI@D-MONs@CS greatly reduced the off-odor caused by the axillary bacteria. • Application of CI@D-MONs@CS was a new and effective strategy to the axillary odor problem. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magnetic resonance technique for temperature-controlled ultrasound irradiation. • Hollow-dendritic-silica-nanoparticles-based smart drug carriers. • Concurrent surfactant removal and α-FeOOH species loading via Fenton reaction. • L-menthol as thermal-sensitive "Flowing Valve" rendering stepwise drug release. • Visualized drug release via magnetic resonance imaging. Focused ultrasound (FUS) controlled drug delivery is maturing towards a highly precise and intelligent approach via the integration of ultrasound-responsive nanocarriers and the state-of-the-art magnetic resonance (MR) technique. Herein, an ultrasound-responsive nanoplatform (Dox@L@FeHD) is developed based on hollow dendritic mesoporous organosilica nanoparticles (HDMONs). Using a facile Fenton reaction, ultrasmall α-FeOOH species are anchored within HDMONs, followed by implanting both doxorubicin (Dox) and L-menthol (LM) to obtain Dox@L@FeHD, which shows a T 1 -T 2 bimodal MR contrast feature. Under mild hyperthermia condition (45 °C), the encapsulated LM undergoes a phase-transition and redistribution ("flowing") within HDMONs, resulting in a rearranged pore structure of Dox@L@FeHD post stimulation. Consequently, Dox shifts from burst release to sustained release, as visualized by MR imaging due to the altered MR contrast feature of Dox@L@FeHD concurrently. In vivo FUS stimulation of Dox@L@FeHD is executed using a self-developed feedback temperature control algorithm to render a constant temperature of 45 °C at the targeted tumor region, thus triggering the in-situ stepwise Dox release, which induces effective retardation of tumor growth. This work demonstrates an elaborate marriage of smart mesoporous nanocarriers and the MR-FUS technique for the accurate regulation of drug release kinetics. [ABSTRACT FROM AUTHOR]

• In-depth introduction of dendritic mesoporous organosilica nanoparticles (DMONs). • The synthetic techniques and mechanisms of DMONs. • The construction strategies to DMONs-based particular architectures. • Current challenges of this novel nanomaterial for future desired applications. • Future prospects and developments of DMONs-related subject. [Display omitted] Dendritic mesoporous organosilica nanoparticles (DMONs) possess three-dimensional (3D) center-radial nanochannels and hierarchical nanopores, which endows themselves with unique structural features and larger pore volumes, more open pore channels, more accessible internal spaces, etc., compared to conventional mesoporous organosilica nanoparticles (MONs). In addition, organic moieties in DMONs skeleton bring about novel biocompatibility, hydrophobicity, and biodegradability, greatly superior to pure inorganic dendritic mesoporous silica nanoparticles (DMSNs) in terms of biochemical applications. Diverse guest species (such as drugs, proteins, or RNA) could be easily loaded onto chemically active sites of the channels' interfaces, achieving their efficient transportation and the subsequent delivery. During the last five years, DMONs have attracted certain degree of attention and experienced non-ignorable development. Therefore, it is necessary and urgent to popularize this brand-new DMONs. To the best of our knowledge, no document has been reported with special focus on its recent progress. For the first time, this comprehensive review provides a critical survey on the synthetic techniques and the corresponding mechanisms of DMONs, DMONs-based particular architectures (like the hollow, core-shell, multi-shelled, etc.), as well as their application domains. Biochemically related applications are emphatically analyzed in the aspects of the design thoughts, manufacturing processes, integrated functionalities, and action mechanisms. It is sincerely expected that this summary and in-depth discussion could give materials scientists and biochemists certain inspiration to accelerate DMONs subject's booming evolution. [ABSTRACT FROM AUTHOR]

Despite the advantages of mesoporous silica nanoparticles (MSNs) in drug delivery, the inherent non-biodegradability seriously impedes the clinical translation of inorganic MSNs, so the current research focus has been turned to mesoporous organosilica nanoparticles (MONs) with higher biocompatibility and easier biodegradability. Recent remarkable advances in silica fabrication chemistry have catalyzed the emergence of a library of MONs with various structures and functions. This review will summarize the latest state-of-the-art studies on the precise control of morphology, structure, framework, particle size and pore size of MONs, which enables the precise synthesis of MONs with suitable engineering for precision stimuli-responsive drug delivery/release, bioimaging and synergistic therapy. Besides, the potential challenges about the future development of MONs are also outlooked with the intention of attracting more researchers to promote the clinical translation of MONs. [ABSTRACT FROM AUTHOR]

• Biodegradable mesoporous organosilica nanoparticles are fabricated via a one-pot synthesis. • Chlorhexidine (CHX) is selected as a cationic template to form the mesoporous structure. • CHX@MONs exhibit GSH-triggered CHX release manner. • CHX@MONs exhibit comparable antibacterial effects with free CHX. • CHX@MONs exhibit less cytotoxicity than free CHX. Chlorhexidine (CHX) is a widely used antiseptic in various infection control practices. In this work, we have developed biodegradable mesoporous organosilica nanoparticles (MONs) through a one-pot synthesis by employing CHX as a bifunctional agent that not any acts as a cationic template to form the structure of mesopores but also serves as a broad-spectrum antiseptic. The resulting CHX@MONs exhibit a relatively high CHX content and glutathione (GSH)-responsive release of CHX via a matrix-degradation-controlled mechanism, leading to comparable antibacterial effects with CHX on both Escherichia coli and Staphylococcus aureus. Furthermore, the effective antibacterial concentration of CHX@MONs shows less cytotoxicity toward normal cells. Our findings will help increase the use of CHX as an antiseptic agent, especially for responsive drug release upon bacterial infection. [ABSTRACT FROM AUTHOR]