Oral pH sensitive GNS@ab nanoprobes for targeted therapy of Helicobacter pylori without disturbance gut microbiome

Recent Progress of Oral Functional Nanomaterials for Intestinal Microbiota Regulation

The gut microbiota is closely associated with human health, and alterations in gut microbiota can influence various physiological and pathological activities in the human body. Therefore, microbiota regulation has become an important strategy in current disease treatment, albeit facing numerous challenges. Nanomaterials, owing to their excellent protective properties, drug release capabilities, targeting abilities, and good biocompatibility, have been widely developed and utilized in pharmaceuticals and dietary fields. In recent years, significant progress has been made in research on utilizing nanomaterials to assist in regulating gut microbiota for disease intervention. This review explores the latest advancements in the application of nanomaterials for microbiota regulation and offers insights into the future development of nanomaterials in modulating gut microbiota.

Self-Healing Guar Gum-Based Nanocomposite Hydrogel Promotes Infected Wound Healing through Photothermal Antibacterial Therapy

Preventing bacterial infections is a crucial aspect of wound healing. There is an urgent need for multifunctional biomaterials without antibiotics to promote wound healing. In this study, we fabricated a guar gum (GG)-based nanocomposite hydrogel, termed GBTF, which exhibited photothermal antibacterial therapy for infected wound healing. The GBTF hydrogel formed a cross-linked network through dynamic borate/diol interactions between GG and borax, thereby exhibiting simultaneously self-healing, adaptable, and injectable properties. Additionally, tannic acid (TA)/Fe3+ nanocomplexes (NCs) were incorporated into the hydrogel to confer photothermal antibacterial properties. Under the irradiation of an 808 nm near-infrared laser, the TA/Fe3+ NCs in the hydrogel could rapidly generate heat, leading to the disruption of bacterial cell membranes and subsequent bacterial eradication. Furthermore, the hydrogels exhibited good cytocompatibility and hemocompatibility, making them a precandidate for preclinical and clinical applications. Finally, they could significantly promote bacteria-infected wound healing by reducing bacterial viability, accelerating collagen deposition, and promoting epithelial remodeling. Therefore, the multifunctional GBTF hydrogel, which was composed entirely of natural substances including guar gum, borax, and polyphenol/ferric ion NCs, showed great potential for regenerating infected skin wounds in clinical applications.

Mucus-Penetrating Nanoassembly as Potential Oral Phototherapeutic Formulation against Multi-Drug Resistant Helicobacter pylori Infection

Helicobacter pylori (H. pylori) infection presents increasing challenges to antibiotic therapies in limited penetration through gastric mucus, multi-drug resistance (MDR), biofilm formation, and intestinal microflora dysbiosis. To address these problems, herein, a mucus-penetrating phototherapeutic nanomedicine (RLs@T780TG) against MDR H. pylori infection is engineered. The RLs@T780TG is assembled with a near-infrared photosensitizer T780T-Gu and an anionic component rhamnolipids (RLs) for deep mucus penetration and light-induced anti-H. pylori performances. With optimized suitable size, hydrophilicity and weak negative surface, the RLs@T780TG can effectively penetrate through the gastric mucus layer and target the inflammatory site. Subsequently, under irradiation, the structure of RLs@T780TG is disrupted and facilitates the T780T-Gu releasing to target the H. pylori surface and ablate multi-drug resistant (MDR) H. pylori. In vivo, RLs@T780TG phototherapy exhibits impressive eradication against H. pylori. The gastric lesions are significantly alleviated and intestinal bacteria balance is less affected than antibiotic treatment. Summarily, this work provides a potential nanomedicine design to facilitate in vivo phototherapy in treatment of H. pylori infection.

Dual-Targeted Graphitic Cascade Nanozymes for Recognition and Treatment of Helicobacter pylori

Helicobacter pylori (H. pylori) is the major etiological factor of a variety of gastric diseases. However, the treatment of H. pylori is challenged by the destruction of targeted drugs by gastric acid and pepsin. Herein, a dual-targeted cascade catalytic nanozyme PtCo@Graphene@Hemin-2(L-arginine) (PtCo@G@H2A) is designed for the treatment of H. pylori. The dual-targeting ability of PtCo@G@H2A is derived from directly targeting the receptor protein of H. pylori through hemin and responding to the acidic environment to cause charge reversal (protonation of L-arginine) to capture H. pylori, achieving efficient targeting effect. Compared with the single-targeting strategy relying on hemin, the dual-targeting strategy can greatly improve the targeting rate, achieving an increase of 850% targeting rate. At the concentration of NaHCO3 in intestinal fluid, the surface potential of PtCo@G@H2A can be quickly restored to avoid side effects. Meanwhile, PtCo@G@H2A has pH-responsive oxidase-like activity, which can generate nitric oxide (NO) through a cascade catalytic process that first generates reactive oxygen species (ROS) with oxygen, and further oxidizes L-arginine through ROS, realizing a superior acid-selective bactericidal effect. Overall, it proposes a promising strategy for the treatment of H. pylori that maintains high targeting and therapeutic effects in the environment of gastric acid and pepsin.

Helicobacter pylori infection in humans and phytotherapy, probiotics, and emerging therapeutic interventions: a review

The global prevalence of Helicobacter pylori (H. pylori) infection remains high, indicating a persistent presence of this pathogenic bacterium capable of infecting humans. This review summarizes the population demographics, transmission routes, as well as conventional and novel therapeutic approaches for H. pylori infection. The prevalence of H. pylori infection exceeds 30% in numerous countries worldwide and can be transmitted through interpersonal and zoonotic routes. Cytotoxin-related gene A (CagA) and vacuolar cytotoxin A (VacA) are the main virulence factors of H. pylori, contributing to its steep global infection rate. Preventative measures should be taken from people's living habits and dietary factors to reduce H. pylori infection. Phytotherapy, probiotics therapies and some emerging therapies have emerged as alternative treatments for H. pylori infection, addressing the issue of elevated antibiotic resistance rates. Plant extracts primarily target urease activity and adhesion activity to treat H. pylori, while probiotics prevent H. pylori infection through both immune and non-immune pathways. In the future, the primary research focus will be on combining multiple treatment methods to effectively eradicate H. pylori infection.

Exosomes: Friends or Foes in Microbial Infections?

The use of new approaches is necessary to address the global issue of infections caused by drug-resistant pathogens. Antimicrobial photodynamic therapy (aPDT) is a promising approach that reduces the emergence of drug resistance, and no resistance has been reported thus far. APDT involves using a photosensitizer (PS), a light source, and oxygen. The mechanism of aPDT is that a specific wavelength of light is directed at the PS in the presence of oxygen, which activates the PS and generates reactive oxygen species (ROS), consequently causing damage to microbial cells. However, due to the PS's poor stability, low solubility in water, and limited bioavailability, it is necessary to employ drug delivery platforms to enhance the effectiveness of PS in photodynamic therapy (PDT). Exosomes are considered a desirable carrier for PS due to their specific characteristics, such as low immunogenicity, innate stability, and high ability to penetrate cells, making them a promising platform for drug delivery. Additionally, exosomes also possess antimicrobial properties, although in some cases, they may enhance microbial pathogenicity. As there are limited studies on the use of exosomes for drug delivery in microbial infections, this review aims to present significant points that can provide accurate insights.

Future Nanotechnology-Based Strategies for Improved Management of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) is a recalcitrant pathogen, which can cause gastric disorders. During the past decades, polypharmacy-based regimens, such as triple and quadruple therapies have been widely used against H. pylori. However, polyantibiotic therapies can disturb the host gastric/gut microbiota and lead to antibiotic resistance. Thus, simpler but more effective approaches should be developed. Here, some recent advances in nanostructured drug delivery systems to treat H. pylori infection are summarized. Also, for the first time, a drug release paradigm is proposed to prevent H. pylori antibiotic resistance along with an IVIVC model in order to connect the drug release profile with a reduction in bacterial colony counts. Then, local delivery systems including mucoadhesive, mucopenetrating, and cytoadhesive nanobiomaterials are discussed in the battle against H. pylori infection. Afterward, engineered delivery platforms including polymer-coated nanoemulsions and polymer-coated nanoliposomes are poposed. These bioinspired platforms can contain an antimicrobial agent enclosed within smart multifunctional nanoformulations. These bioplatforms can prevent the development of antibiotic resistance, as well as specifically killing H. pylori with no or only slight negative effects on the host gastrointestinal microbiota. Finally, the essential checkpoints that should be passed to confirm the potential effectiveness of anti-H. pylori nanosystems are discussed.

Stimulus-responsive biomaterials for Helicobacter pylori eradication

BACKGROUND

Helicobacter pylori (H. pylori), the only bacterium classified as a type I (definite) carcinogen, is strongly associated with the development of gastric inflammation and adenocarcinoma. It infects the stomach of approximately half of the global population, equivalent to nearly 4.4 billion people. However, due to physiological barriers in the stomach, microbial barriers and increased antibiotic resistance, the therapeutic efficiency of standard antibiotic therapy is limited and cannot meet the clinical needs in some areas. Combining stimulus-responsive biomaterials with certain stimuli is an emerging antibacterial strategy. Stimulus-responsive biomaterials can respond to chemical, biological or physical cues in the environment with corresponding changes in their own properties and functions, highlighting a more intelligent, targeting and efficient aspect for H. pylori therapy.

AIM OF REVIEW

This review describes the critical obstacles in the current treatment of H. pylori, summarizes the recent advances in stimulus-responsive biomaterials against H. pylori by elucidating their working mechanisms and antibacterial performances under different types of stimuli (pH, enzymes, light, magnetic and ultrasound irradiations), and attempts to analyze the future prospects of such smart biomaterial for H. pylori eradication. Key Scientific Concepts of Review: Any characteristic property or change in the biomilieu at the H. pylori infected site (endogenous stimuli) or specific iatrogenic conditions in vitro (exogenous stimuli) can act as cues to activate or potentiate the antibacterial activity of responsive biomaterials. The responsiveness of these materials to endogenous stimuli enhances antimicrobial targeting, and makes physiological barriers that would otherwise hinder conventional H. pylori therapies a key factor in facilitating antibacterial effects. The responsiveness to exogenous stimuli greatly prolongs the action time of antimicrobial materials and pinpoints the site of infection, thereby reducing toxic side effects. These findings pave the way for the development of more precise and effective anti-H. pylori treatment.

Advancing biofilm management through nanoformulation strategies: a review of dosage forms and administration routes

Biofilms are complex microbial communities formed by the attachment of bacteria or fungi to surfaces encased in a self-produced polymeric matrix. These biofilms are highly resistant to conventional antimicrobial therapies. The resistance mechanisms exhibited by biofilms include low antibiotic absorption, sluggish replication, adaptive stress response, and the formation of dormant-like phenotypes. The eradication of biofilms requires alternative strategies and approaches. Nanotechnological drug delivery systems allow excellent control over the drug chemistry, surface area, particle size, particle shape, and composition of nanostructures. Nanoformulations can enhance the efficacy of antimicrobial agents by improving their bioavailability, stability, and targeted delivery to the site of infection that helps biofilm eradication more effectively. In addition to nanoformulations, the route of administration and choice of dosage forms play a crucial role in treating biofilm infections. Systemic administration of antibiotics is effective in controlling systemic infection and sepsis associated with biofilms. Alternative routes of administration, such as inhalation, vaginal, ocular, or dermal, have been explored to target biofilm infections in specific organs. This review primarily examines the utilisation of nanoformulations in various administration routes for biofilm management. It also provides an overview of biofilms, current approaches, and the drawbacks associated with conventional methods.

Microparticles and nanoparticles-based approaches to improve oral treatment of Helicobacter pylori infection

Helicobacter pylori is a gram-negative, spiral-shaped, flagellated bacterium that colonizes the stomach of half the world's population. Helicobacter pylori infection causes pathologies of varying severity. Standard oral therapy fails in 15-20% since the barriers of the oral route decrease the bioavailability of antibiotics and the intrinsic factors of bacteria increase the rates of resistance. Nanoparticles and microparticles are promising strategies for drug delivery into the gastric mucosa and targeting H. pylori. The variety of building blocks creates systems with distinct colloidal, surface, and biological properties. These features improve drug-pathogen interactions, eliminate drug depletion and overuse, and enable the association of multiple actives combating H. pylori on several fronts. Nanoparticles and microparticles are successfully used to overcome the barriers of the oral route, physicochemical inconveniences, and lack of selectivity of current therapy. They have proven efficient in employing promising anti-H. pylori compounds whose limitation is oral route instability, such as some antibiotics and natural products. However, the current challenge is the applicability of these strategies in clinical practice. For this reason, strategies employing a rational design are necessary, including in the development of nano- and microsystems for the oral route.

Photothermal/Photoacoustic Therapy Combined with Metal-Based Nanomaterials for the Treatment of Microbial Infections

The increased spread and persistence of bacterial drug-resistant phenotypes remains a public health concern and has contributed significantly to the challenge of combating antibiotic resistance. Nanotechnology is considered an encouraging strategy in the fight against antibiotic-resistant bacterial infections; this new strategy should improve therapeutic efficacy and minimize side effects. Evidence has shown that various nanomaterials with antibacterial performance, such as metal-based nanoparticles (i.e., silver, gold, copper, and zinc oxide) have intrinsic antibacterial properties. These antibacterial agents, such as those made of metal oxides, carbon nanomaterials, and polymers, have been used not only to improve antibacterial efficacy but also to reduce bacterial drug resistance due to their interaction with bacteria and their photophysical properties. These nanostructures have been used as effective agents for photothermal therapy (PTT) and photodynamic therapy (PDT) to kill bacteria locally by heating or the controlled production of reactive oxygen species. Additionally, PTT or PDT therapies have also been combined with photoacoustic (PA) imaging to simultaneously improve treatment efficacy, safety, and accuracy. In this present review, we present, on the one hand, a summary of research highlighting the use of PTT-sensitive metallic nanomaterials for the treatment of bacterial and fungal infections, and, on the other hand, an overview of studies showing the PA-mediated theranostic functionality of metal-based nanomaterials.

Artificial intelligence in theranostics of gastric cancer, a review

Gastric cancer (GC) is one of the commonest cancers with high morbidity and mortality in the world. How to realize precise diagnosis and therapy of GC owns great clinical requirement. In recent years, artificial intelligence (AI) has been actively explored to apply to early diagnosis and treatment and prognosis of gastric carcinoma. Herein, we review recent advance of AI in early screening, diagnosis, therapy and prognosis of stomach carcinoma. Especially AI combined with breath screening early GC system improved 97.4 % of early GC diagnosis ratio, AI model on stomach cancer diagnosis system of saliva biomarkers obtained an overall accuracy of 97.18 %, specificity of 97.44 %, and sensitivity of 96.88 %. We also discuss concept, issues, approaches and challenges of AI applied in stomach cancer. This review provides a comprehensive view and roadmap for readers working in this field, with the aim of pushing application of AI in theranostics of stomach cancer to increase the early discovery ratio and curative ratio of GC patients.

Recent Advances in Pharmaceutical Approaches of Antimicrobial Agents for Selective Delivery in Various Administration Routes

Globally, the increase of pathogenic bacteria with antibiotic-resistant characteristics has become a critical challenge in medical treatment. The misuse of conventional antibiotics to treat an infectious disease often results in increased resistance and a scarcity of effective antimicrobials to be used in the future against the organisms. Here, we discuss the rise of antimicrobial resistance (AMR) and the need to combat it through the discovery of new synthetic or naturally occurring antibacterial compounds, as well as insights into the application of various drug delivery approaches delivered via various routes compared to conventional delivery systems. AMR-related infectious diseases are also discussed, as is the efficiency of various delivery systems. Future considerations in developing highly effective antimicrobial delivery devices to address antibiotic resistance are also presented here, especially on the smart delivery system of antibiotics.

A review on the research progress on non-pharmacological therapy of Helicobacter pylori

Helicobacter pylori is a pathogenic microorganism that mainly resides in the human stomach and is the major cause of chronic gastritis, peptic ulcer and gastric cancer. Up to now, the treatment of Helicobacter pylori has been predominantly based on a combination of antibiotics and proton pump inhibitors. However, the increasing antibiotic resistance greatly limits the efficacy of anti-Helicobacter pylori treatment. Turning to non-antibiotic or non-pharmacological treatment is expected to solve this problem and may become a new strategy for treating Helicobacter pylori. In this review, we outline Helicobacter pylori’s colonization and virulence mechanisms. Moreover, a series of non-pharmacological treatment methods for Helicobacter pylori and their mechanisms are carefully summarized, including probiotics, oxygen-rich environment or hyperbaric oxygen therapy, antibacterial photodynamic therapy, nanomaterials, antimicrobial peptide therapy, phage therapy and modified lysins. Finally, we provide a comprehensive overview of the challenges and perspectives in developing new medical technologies for treating Helicobacter pylori without drugs.

Application of biomaterials in the eradication of Helicobacter pylori: A bibliometric analysis and overview

Helicobacter pylori is a prominent cause of gastritis, peptic ulcer, and gastric cancer. It is naturally colonized on the surface of the mucus layer and mucosal epithelial cells of the gastric sinus, surrounded not only by mucus layer with high viscosity that prevents the contact of drug molecules with bacteria but also by multitudinous gastric acid and pepsin, inactivating the antibacterial drug. With high-performance biocompatibility and biological specificity, biomaterials emerge as promising prospects closely associated with H. pylori eradication recently. Aiming to thoroughly summarize the progressing research in this field, we have screened 101 publications from the web of science database and then a bibliometric investigation was performed on the research trends of the application of biomaterials in eradicating H. pylori over the last decade utilizing VOSviewer and CiteSpace to establish the relationship between the publications, countries, institutions, authors, and most relevant topics. Keyword analysis illustrates biomaterials including nanoparticles (NPs), metallic materials, liposomes, and polymers are employed most frequently. Depending on their constituent materials and characterized structures, biomaterials exhibit diverse prospects in eradicating H. pylori regarding extending drug delivery time, avoiding drug inactivation, target response, and addressing drug resistance. Furthermore, we overviewed the challenges and forthcoming research perspective of high-performance biomaterials in H. pylori eradication based on recent studies.

Advances in Oral Drug Delivery Systems: Challenges and Opportunities

The oral route is the most preferred route for systemic and local drug delivery. However, the oral drug delivery system faces the harsh physiological and physicochemical environment of the gastrointestinal tract, which limits the bioavailability and targeted design of oral drug delivery system. Innovative pharmaceutical approaches including nanoparticulate formulations, biomimetic drug formulations, and microfabricated devices have been explored to optimize drug targeting and bioavailability. In this review, the anatomical factors, biochemical factors, and physiology factors that influence delivering drug via oral route are discussed and recent advance in conventional and novel oral drug delivery approaches for improving drug bioavailability and targeting ability are highlighted. We also address the challenges and opportunities of oral drug delivery systems in future.

Phototherapy and Mechanism Exploration of Biofilm and Multidrug-Resistant Helicobacter pylori by Bacteria-Targeted NIR Photosensitizer

Helicobacter pylori (H. pylori) infection has been the leading cause of gastric cancer development. In recent years, the resistance of H. pylori against antibiotic treatment has been a great challenge for most countries worldwide. Since biofilm formation is one of the reasons for the antibiotic resistance of H. pylori, and phototherapy has emerged as a promisingly alternative antibacterial treatment, herein the bacteria-targeted near-infrared (NIR) photosensitizer (T780T-Gu) by combining positively-charged guanidinium (Gu) with an efficient phototherapeutic agent T780T is developed. The proposed molecule T780T-Gu exhibits synergistic photothermal therapy/photodynamic therapy effect against both H. pylori biofilms and multidrug-resistant (MDR) clinical strains. More importantly, the phototherapy mechanism of T780T-Gu acquired by the RNA-seq analysis indicates that structural deficiency as well as a decrease in metabolism and defense activity are the possible reasons for the efficient H. pylori phototherapy.

pH and its applications in targeted drug delivery

Physiologic pH is vital for the normal functioning of tissues and varies in different parts of the body. The varying pH of the body has been exploited to design pH-sensitive smart oral, transdermal and vaginal drug delivery systems (DDS). The DDS demonstrated promising results in hard-to-treat diseases such as cancer and Helicobacter pylori infection. In some cases, a change in pH of tissues or body fluids has also been employed as a useful diagnostic biomarker. This paper aims to comprehensively review the development and applications of pH-sensitive DDS as well as recent advances in the field.

Metal-Based Nanoparticles: A Prospective Strategy for Helicobacter pylori Treatment

Helicobacter pylori (H. pylori) is an infectious pathogen and the leading cause of gastrointestinal diseases, including gastric adenocarcinoma. Currently, bismuth quadruple therapy is the recommended first-line treatment, and it is reported to be highly effective, with >90% eradication rates on a consistent basis. However, the overuse of antibiotics causes H. pylori to become increasingly resistant to antibiotics, making its eradication unlikely in the foreseeable future. Besides, the effect of antibiotic treatments on the gut microbiota also needs to be considered. Therefore, effective, selective, antibiotic-free antibacterial strategies are urgently required. Due to their unique physiochemical properties, such as the release of metal ions, the generation of reactive oxygen species, and photothermal/photodynamic effects, metal-based nanoparticles have attracted a great deal of interest. In this article, we review recent advances in the design, antimicrobial mechanisms and applications of metal-based nanoparticles for the eradication of H. pylori. Additionally, we discuss current challenges in this field and future perspectives that may be used in anti-H. pylori strategies.

Biomaterials for Helicobacter pylori therapy: therapeutic potential and future perspectives

Helicobacter pylori (H. pylori) is the main cause of gastric adenocarcinoma. However, the traditional antibiotic treatment of H. pylori is limited due to increased antibiotic resistance and low efficacy; low drug delivery efficiency and difficulties in eradicating H. pylori that is present intracellularly or in biofilms cause further setbacks. Biomaterials that can protect drugs against stomach acid, target lesions, control drug release, destroy biofilms, and exhibit unique antibacterial mechanisms and excellent biocompatibility have emerged as attractive tools for H. pylori eradication, particularly for drug-resistant strains. Herein, we review the virulence mechanisms, current drug treatments, and antibiotic resistance of H. pylori strains. Furthermore, recent advances in the development of biomaterials, including nanoparticles (such as lipid-based nanoparticles, polymeric nanoparticles, and inorganic nanoparticles), microspheres, and hydrogels, for effective and precise therapy of H. pylori and different types of therapeutic mechanisms, as well as future perspectives, have also been summarized.

Nanocluster-mediated photothermia improves eradication efficiency and antibiotic sensitivity of Helicobacter pylori

Background

Helicobacter pylori (H. pylori) eradication plays a crucial role in gastric cancer prevention, but the antimicrobial resistance of H. pylori is obstructing this elimination process. In this study, we developed nanoclusters (NCs) from Zn0.3Fe2.7O4 nanoparticles using a poly(ethylene glycol)-b-poly(ε-caprolactone)-based nanocarrier as an innovative antibiotic-independent H. pylori management.

Results

The nanocluster showed minimal toxicity and maximal biocompatibility. With a low concentration (50 µg/mL) of NCs under a short time period (~ 2 min) of near-infrared (808 nm) irradiation, we kept the culture medium temperature to 41 °C for 20 min with continuous irradiation. The heated NCs exhibited efficient photothermal effects and resulted in an excellent inhibition of H. pylori growth, adhesion and ability to induce vacuolization in eukaryotic cells in in vitro investigation. Transmission electron microscopy showed a dramatic morphologic change after NCs photothermia on H. pylori, including cell wall and membrane rupture, as well as ribosome damage. Besides, levofloxacin and clarithromycin resistance was decreased after photothermal treatment in H. pylori NCTC 11637 and/or clinical strains, however metronidazole resistance was unchanged. We also discovered a significant decrease in the biofilm formation of H. pylori under the NCs-based photothermal application, while efflux pump function was unchanged.

Conclusions

Based on this novel NCs-based photothermal approach, we were able to demonstrate in vitro a significant inhibition of both H. pylori growth and molecular toxicity, and its improvement in antibiotic sensitivity alone with the eradication of H. pylori biofilms previously believed to be tolerant to conventional antibiotics.

Antibody-conjugated liposomes loaded with indocyanine green for oral targeted photoacoustic imaging-guided sonodynamic therapy of Helicobacter pylori infection

Helicobacter pylori is a causative factor of various gastrointestinal tract diseases. As clinical antibiotic-based therapy for H. pylori infection might induce bacterial drug resistance, the in vivo eradication of H. pylori remains a huge challenge. In the present study, monoclonal antibody-conjugated liposomes loaded with indocyanine green (ICG) (HpAb-LiP-ICG) were successfully developed for targeted photoacoustic (PA) imaging-guided sonodynamic therapy (SDT) of H. pylori infection in vivo. HpAb-LiP-ICG showed high stability and favorable biocompatibility in acidic environment (pH 1.5) and was used for treating H. pylori-infected mice through oral administration. PA imaging showed that HpAb-LiP-ICG could precisely recognize and target H. pylori in the stomach. Following the targeting of HpAb-LiP-ICG to H. pylori, ICG was activated to generate singlet oxygen (¹O₂) for eliminating H. pylori under ultrasound (US) irradiation. Pathological analysis revealed that the HpAb-LiP-ICG-mediated SDT eradicated H. pylori without unintended toxicity to normal tissues. In conclusion, the HpAb-LiP-ICG-mediated SDT might shed new light on treating H. pylori infection, indicating the clinical translational prospects of this therapy in near future. STATEMENT OF SIGNIFICANCE: Traditional antibiotic-based therapy for Helicobacter pylori infections suffers from the risk of drug resistance. To meet this challenge, a monoclonal antibody-conjugated nanoliposome loaded with indocyanine green (ICG) (HpAb-LiP-ICG) was successfully developed, and efficient eradication of H. pylori was achieved in vivo by visual sonodynamic therapy (SDT). HpAb-LiP-ICG exhibited biocompatibility, targeting, and stability in the acidic microenvironment. Under ultrasound (US) irradiation in vitro, the HpAb-LiP-ICG nanoliposomes accumulated on the surface of H. pylori were activated to produce adequate singlet oxygen (¹O₂) to eliminate H. pylori. Gastric mucous tissues infected with H. pylori recovered to the normal state after HpAb-LiP-ICG-mediated SDT without side effects, thus highlighting the clinical translational prospects of the prepared HpAb-LiP-ICG nanoliposome in near future.

Recent advances in nanoparticle-based targeting tactics for antibacterial photodynamic therapy

Abstract

The rise of antibacterial drug resistance means treatment options are becoming increasingly limited. We must find ways to tackle these hard-to-treat drug-resistant and biofilm infections. With the lack of new antibacterial drugs (such as antibiotics) reaching the clinics, research has switched focus to exploring alternative strategies. One such strategy is antibacterial photodynamic therapy (aPDT), a system that relies on light, oxygen, and a non-toxic dye (photosensitiser) to generate cytotoxic reactive oxygen species. This technique has already been shown capable of handling both drug-resistant and biofilm infections but has limited clinical approval to date, which is in part due to the low bioavailability and selectivity of hydrophobic photosensitisers. Nanotechnology-based techniques have the potential to address the limitations of current aPDT, as already well-documented in anti-cancer PDT. Here, we review recent advances in nanoparticle-based targeting tactics for aPDT.

Graphical Abstract

Combatting Helicobacter pylori with oral nanomedicines

Helicobacter pylori (H. pylori) infection is considered to be the main cause of most digestive diseases,such as chronic active gastritis, gastroduodenal ulcers, or even gastric cancer. Oral medication is a transformative approach to treat H. pylori-induced infections. However, unlike intravenous administration, orally administrated drugs have to overcome various barriers before reaching the infected sites, which significantly limits the therapeutic efficacy. These challenges may be addressed by emerging nanomedicine that is equipped with nanotechnology approaches to enable efficient and effective targeted delivery of drugs. Herein, in this review, we first discuss the conventional therapy for the eradication of H. pylori. Through the introduction of the critical barriers of oral administration, the benefits of nanomedicine are highlighted. Recently-published examples of nanocarriers for combating H. pylori in terms of design, preparation, and antimicrobial mechanisms are then presented, followed by our perspective on potential future research directions of oral nanomedicines.

A Mg2+/polydopamine composite hydrogel for the acceleration of infected wound healing

Bacterial infection is a vital factor to delay the wound healing process. The antibiotics abuse leads to drug resistance of some pathogenic bacteria. Non-antibiotic-dependent multifunctional biomaterials with accelerated wound healing performance are urgently desired. Herein, we reported a composite antibacterial hydrogel PDA-PAM/Mg²⁺ that shows excellent self-healing and tissue adhesive property, and photothermal antibacterial functions for accelerating wound healing. The gel was composed of polyacrylamide (PAM), polydopamine (PDA), and magnesium (Mg²⁺) and prepared via a two-step procedure: an alkali-induced dopamine pre-polymerization and followed radical polymerization process. The composite gel shows excellent tissue adhesiveness and Mg²⁺-synergized photothermal antibacterial activity, inducing a survival rate of 5.29% for S. aureus and 7.06% for E. coli after near infrared light irradiation. The composite hydrogel further demonstrated efficient bacteria inhibition, enhanced wound healing and collagen deposition in a full-thickness skin defect rat model. Together, the PDA-PAM/Mg²⁺ hydrogel presents an excellent wound dressing with excellent tissue adhesion, wound healing, and antibacterial functions.

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A self-healing multifunctional hydrogel with photothermal antibacterial properties was developed and applied in wound healing.

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The hydrogel exhibited enhanced self-healing and adhesion properties.

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The hydrogel exhibited excellent photothermal effect and photothermal stability and repeatability.

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The hydrogel could accelerate wound healing by promoting cell proliferation and collagen deposition.

Helicobacter pylori infection: from standard to alternative treatment strategies

Helicobacter pylori is the major component of the gastric microbiome of infected individuals and one of the aetiological factors of chronic gastritis, peptic ulcer disease and gastric cancer. The increasing resistance to antibiotics worldwide has made the treatment of H. pylori infection a challenge. As a way to overhaul the efficacy of currently used H. pylori antibiotic-based eradication therapies, alternative treatment strategies are being devised. These include probiotics and prebiotics as adjuvants in H. pylori treatment, antimicrobial peptides as alternatives to antibiotics, photodynamic therapy ingestible devices, microparticles and nanoparticles applied as drug delivery systems, vaccines, natural products, and phage therapy. This review provides an updated synopsis of these emerging H. pylori control strategies and discusses the advantages, hurdles, and challenges associated with their development and implementation. An effective human vaccine would be a major achievement although, until now, projects regarding vaccine development have failed or were discontinued. Numerous natural products have demonstrated anti-H. pylori activity, mostly in vitro, but further clinical studies are needed to fully disclose their role in H. pylori eradication. Finally, phage therapy has the potential to emerge as a valid alternative, but major challenges remain, namely the isolation of more H. pylori strictly virulent bacterio(phages).

Effect of Temperature on Metronidazole Resistance in Helicobacter pylori

Efficacy of Helicobacter pylori (H. pylori) eradication therapy has declined due to rapid rises in antibiotic resistance. We investigated how increased temperature affected H. pylori (NCTC 11637) growth and its sensitivity to metronidazole in vitro. We performed transcriptomic profiling using RNA-sequencing to identify differentially expressed genes (DEGs) associated with increased temperature. Transcriptional pathways involved in temperature-driven metronidazole resistance changes were analyzed through bioinformatic and literature curation approaches. We showed that H. pylori growth was inhibited at 41°C and inhibition was more apparent with prolonged incubation. Resistance to metronidazole was also reduced—minimum inhibitory concentration for metronidazole decreased from > 256 μg/ml at 37°C to 8 μg/ml at 41°C after culturing for 3 days. RNA-sequencing results, which were highly concordant within treatment conditions, revealed more than one third of genes (583/1,552) to be differentially expressed at increased temperatures with similar proportions up and down-regulated. Quantitative real-time PCR validation for 8 out of 10 DEGs tested gave consistent direction in gene expression changes. We found enrichment for redox and oxygen radical pathways, highlighting a mechanistic pathway driving temperature-related metronidazole resistance. Independent literature review of published genes associated with metronidazole resistance revealed 46 gene candidates, 21 of which showed differential expression and 7 out of 9 DEGs associated with “redox” resistance pathways. Sanger sequencing did not detect any changes in genetic sequences for known resistance genes rdxA, frxA nor fdxB. Our findings suggest that temperature increase can inhibit the growth and reduce H. pylori resistance to metronidazole. Redox pathways are possible potential drivers in metronidazole resistance change induced by temperature. Our study provides insight into potential novel approaches in treating antibiotic resistant H. pylori.

Gut Microbiota: Influence on Carcinogenesis and Modulation Strategies by Drug Delivery Systems to Improve Cancer Therapy

Gut microbiota have close interactions with the host. It can affect cancer progression and the outcomes of cancer therapy, including chemotherapy, immunotherapy, and radiotherapy. Therefore, approaches toward the modulation of gut microbiota will enhance cancer prevention and treatment. Modern drug delivery systems (DDS) are emerging as rational and promising tools for microbiota intervention. These delivery systems have compensated for the obstacles associated with traditional treatments. In this review, the essential roles of gut microbiota in carcinogenesis, cancer progression, and various cancer therapies are first introduced. Next, advances in DDS that are aimed at enhancing the efficacy of cancer therapy by modulating or engineering gut microbiota are highlighted. Finally, the challenges and opportunities associated with the application of DDS targeting gut microbiota for cancer prevention and treatment are briefly discussed.

Cyclic Anhydrides as Powerful Tools for Bioconjugation and Smart Delivery

Cyclic anhydrides are potent tools for bioconjugation; therefore, they are broadly used in the functionalization of biomolecules and carriers. The pH-dependent stability and reactivity, as well as the physical properties, can be tuned by the structure of the cyclic anhydride used; thus, their application in smart delivery systems has become very important. This review intends to cover the last updates in the use of cyclic anhydrides as pH-sensitive linkers, their differences in reactivity, and the latest applications found in bioconjugation chemistry or chemical biology, and when possible, in drug delivery.

Gold nanoparticles to enhance ophthalmic imaging

The use of gold nanoparticles as diagnostic tools is burgeoning, especially in the cancer community with a focus on theranostic applications to both cancer diagnosis and treatment. Gold nanoparticles have also demonstrated great potential for use in diagnostic and therapeutic approaches in ophthalmology. Although many ophthalmic imaging modalities are available, there is still a considerable unmet need, in particular for ophthalmic molecular imaging for the early detection of eye disease before morphological changes are more grossly visible. An understanding of how gold nanoparticles are leveraged in other fields could inform new ways they could be utilized in ophthalmology. In this paper, we review current ophthalmic imaging techniques and then identify optical coherence tomography (OCT) and photoacoustic imaging (PAI) as the most promising technologies amenable to the use of gold nanoparticles for molecular imaging. Within this context, the development of gold nanoparticles as OCT and PAI contrast agents are reviewed, with the most recent developments described in detail.

Beyond Antibiotics: Photo/Sonodynamic Approaches for Bacterial Theranostics

Rapid evolution and propagation of multidrug resistance among bacterial pathogens are outpacing the development of new antibiotics, but antimicrobial photodynamic therapy (aPDT) provides an excellent alternative. This treatment depends on the interaction between light and photoactivated sensitizer to generate reactive oxygen species (ROS), which are highly cytotoxic to induce apoptosis in virtually all microorganisms without resistance concern. When replacing light with low-frequency ultrasonic wave to activate sensitizer, a novel ultrasound-driven treatment emerges as antimicrobial sonodynamic therapy (aSDT). Recent advances in aPDT and aSDT reveal golden opportunities for the management of multidrug resistant bacterial infections, especially in the theranostic application where imaging diagnosis can be accomplished facilely with the inherent optical characteristics of sensitizers, and the generated ROS by aPDT/SDT cause broad-spectrum oxidative damage for sterilization. In this review, we systemically outline the mechanisms, targets, and current progress of aPDT/SDT for bacterial theranostic application. Furthermore, potential limitations and future perspectives are also highlighted.

Fullerenol Nanoparticles Eradicate Helicobacter pylori via pH-Responsive Peroxidase Activity

Helicobacter pylori (H. pylori) eradication by antibiotics and proton pump inhibitor treatment is limited by the low pH microenvironment in the stomach and can lead to antibiotic resistance. We fabricated fullerenol nanoparticles (FNPs) with varied chemical structures responding to a pinacol rearrangement of vicinal hydroxyl to form carbonyls in low pH environments. An obvious increase in C═O/C-O was induced in low pH and was positively correlated with a peroxidase-like activity. The FNPs exerted an excellent effect on H. pylori eradication in vitro and in vivo because of their peroxidase-like activity. FNP treatment of a H. pylori biofilm revealed that FNPs broke down polysaccharides in cell wall components, resulting in collapse of the bacteria. The cycles of FNPs combining and dissociating with the peroxidase substrate were detected by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and confirmed that FNPs enhance peroxidase-like activity. Further, the isothermal titration calorimetry results showed that FNPs with more C═O/C-O had greater affinity to bind the peroxidase substrates. Therefore, we suggest that varied C═O/C-O serves as a switch to respond to low pH in the stomach to kill H. pylori by inducing a peroxidase-like activity. FNPs can also overcome the challenge of antibiotic resistance to achieve H. pylori eradication in the stomach.