pH and its applications in targeted drug delivery

A recent review on smart sensor-integrated wound dressings: Real-time monitoring and on-demand therapeutic delivery

Wound management is a critical aspect of healthcare, necessitating continuous monitoring and timely interventions to ensure optimal healing outcomes. In recent years, the integration of sensor technology into wound dressings has emerged as a transformative approach, enabling real-time monitoring of healing parameters and facilitating on-demand treatment delivery. Sensor-based wound dressings leverage various sensing modalities, including temperature, pH, moisture, oxygen, and other biochemical markers, to provide comprehensive insights into the wound microenvironment. These dressings are equipped with miniaturized sensors capable of transmitting the data wirelessly, facilitating remote monitoring and timely interventions. Moreover, some advanced dressings incorporate responsive drug delivery systems, enabling the on-demand release of therapeutics based on real-time sensor feedback. Additionally, the incorporation of on-demand treatment mechanisms allows targeted delivery of therapeutics based on the specific needs of the wound, further enhancing the efficacy of the healing process. This comprehensive approach improves patient outcomes by promoting faster and more effective wound healing and reducing the burden through streamlined monitoring and treatment protocols. This paper presents an overview of recent advancements in sensor technology applied to wound healing, focusing on their role in monitoring wound parameters and delivering targeted therapy. These sensors leverage temperature, pH, and glucose sensing modalities to provide comprehensive insights into the healing process.

Advanced oral drug delivery systems for gastrointestinal targeted delivery: the design principles and foundations

Oral administration has long been considered the most convenient method of drug delivery, requiring minimal expertise and invasiveness. Unlike injections, it avoids discomfort, wound infections, and complications, leading to higher patient compliance. However, the effectiveness of oral delivery is often hindered by the harsh biological barriers of the gastrointestinal tract, which limit the bioaccessibility and bioavailability of drugs. The development of oral drug delivery systems (ODDSs) represents a critical area for the advancement of pharmacotherapy. This review highlights the characteristics and precise targeting mechanisms of ODDSs. It first examines the unique properties of each gastrointestinal compartment, including the stomach, small intestine, intestinal mucus, intestinal epithelial barrier, and colon. Based on these features, it outlines the targeting strategies and design principles for ODDSs aimed at overcoming gastrointestinal barriers to enhance disease treatment. Lastly, the review discusses the challenges and potential future directions for ODDS development, emphasizing their importance for advancing drug delivery technologies and accelerating their future growth.

Investigation of ex vivo vaginal tissue deposition and antimicrobial screening- A proof-of-concept study with doxycycline-infused in situ sol-gel for localised gonorrhoea management

Antimicrobial resistance (AMR) associated with the leading sexually transmitted infections (STIs) such as gonorrhoea, chlamydia, and trichomoniasis has resulted in significant challenges in the prevention and treatment of these infections using current approaches. To address this, the intravaginal sol-gel platform holds immense potential, as the female reproductive tract (FRT) is the primary site of invasion and colonisation of STI-causing organisms, herein, Neisseria gonorrhoeae. The lead sol-gels, F5 and F9 demonstrate relatively low doxycycline hyclate (DOXH) tissue permeability (10.18 ± 1.56 % and 4.49 ± 1.53 %, respectively), while displaying substantive tissue deposition (2372.95 ± 135.79 µg/g and 2187.73 ± 95.29 µg/g respectively) at 8 h in ex vivo bovine vaginal mucosal tissue. Furthermore, the attenuation of the deleterious effect of DOXH by the sol-gel platform on HeLa cell viability presents it as a safe drug delivery vehicle. The distinct possibility of dose reduction is demonstrated by the negligible differences in the zone of inhibition (ZoI) for sensitive isolates of N. gonorrhoeae with half-strength (0.25 % w/w) and full-strength (0.5 % w/w) DOXH sol-gels. In summary, intravaginal delivery using engineered DOXH-infused sol-gels presents a demonstrable solution to STI prevention/treatment with the potential to reduce AMR risk through localised drug delivery, dose reduction, and increased patient compliance.

Magnetic mesoporous silica nanoparticles as advanced polymeric scaffolds for efficient cancer chemotherapy: recent progress and challenges

Magnetic mesoporous silica nanoparticles (MMS NPs) stand out as excellent options for targeted chemotherapy owing to their remarkable features, such as extensive surface area, substantial pore volume, adjustable and uniform pore size, facile scalability, and versatile surface chemistry. This review comprehensively explores the latest developments in MMS NPs, emphasizing their design, functionalization, and application in cancer therapy. Initially, we discuss the critical need for targeted and controlled drug delivery (DD) in oncology, highlighting the role of magnetic and MMs in addressing some challenges. Subsequently, the key features of MMS NPs, such as their high surface area, pore structure, and functionalization strategies, are examined for their impact on their DD performance for efficient cancer chemotherapy. The integration of chemotherapy methods such as photothermal therapy and photodynamic therapy with MMS NPs is also explored, showcasing multifunctional platforms that combine imaging and therapeutic capabilities. Finally, we identify the current challenges and provide future perspectives for the development and clinical translation of MMS NPs, underscoring their potential to reshape CT paradigms.

Fast pH-Driven Solubilization Method of Realgar (As4S4) to Reduce the Toxicity of Arsenic [As(III)] for Medicinal Purposes

Acute promyelocytic leukemia (APL) accounts for 5-15% of acute myeloid leukemia cases. It is typically characterized by the (15;17) chromosomal translocation, producing the pathogenic retinoic acid receptor (RAR) alpha/promyelocytic leukemia (PML) fusion protein. Recently, remission of APL has been achieved using the first chemotherapy-independent oral drug regimen in anticancer therapy, consisting of all-trans retinoic acid (targeting RARalpha) and the arsenic sulfide realgar (targeting PML). However, clinical adoption of realgar and the characterization of its active breakdown products have been hampered by its poor solubility. Here, a scalable pH/temperature-based process is described that partially mimics gut transition, achieving fast and reproducible solubilization of realgar. Six different spectroscopic and spectrometric techniques are employed to investigate solubilized realgar. Furthermore, it is shown that solubilized realgar targets PML, displaying wider in vitro therapeutic indices and lower off-target effects than arsenic trioxide, the current APL standard of care. Moreover, in line with evidence of an interplay between PML and HIV persistence, solubilized realgar can disrupt HIV latency, the main barrier to an HIV/AIDS cure, in CD4 T cells of people living with HIV. These findings may open avenues for streamlining realgar solubilization and designing less toxic, orally administrable arsenic-based therapies.

Harnessing the Power of Antimicrobial Peptides: From Mechanisms to Delivery Optimization for Topical Infections

Antimicrobial peptides (AMPs) have emerged as promising agents for treating topical infections due to their enhanced biocompatibility and resistance to systemic degradation. AMPs possess host immunomodulatory effects and disintegrate bacterial cell membranes, a mechanism less prone to microbial resistance compared to conventional antibiotics, making AMPs potential candidates for antimicrobial delivery. The review discusses the challenges posed by antimicrobial resistance (AMR) and explores the mechanisms by which bacteria develop resistance to AMPs. The authors provide a detailed analysis of the mechanisms of action of AMPs, their limitations, and strategies to improve their efficacy. Conventional AMP delivery systems, including polymeric, synthetic, and lipid-based nanoparticles and cubosomes, face challenges of microbial resistance mechanisms via efflux pump systems, bacterial cell membrane modifications, and protease enzyme release. This review explores strategies to optimize these delivery systems. Furthermore, market statistics and the growing interest in peptide antibiotics have been explored in this review. The authors provide future research directions, such as exploring gene-targeting approaches to combat emerging bacterial resistance against AMPs, and emphasize considering the conformational stability of peptides, the skin microbiome's nature at the infection site, and proteolytic stability for developing efficient AMP delivery systems for topical infections.

Development and optimization of raloxifene hydrochloride loaded lipid nanocapsule based hydrogel for transdermal delivery

AIM

Development and optimization of raloxifene hydrochloride loaded lipid nanocapsule hydrogel for transdermal delivery.

METHOD

A 33 Box-Behnken Design and numerical optimization was performed to obtain the optimized formulation. Subsequently, the optimized raloxifene hydrochloride loaded lipid nanocapsule was developed using phase inversion temperature and characterized for physicochemical properties. Furthermore, the optimized lipid nanocapsule was loaded into a hydrogel and evaluated for rheology, spreadability, ex-vivo skin permeation, deposition and irritation.

RESULTS

The numerical optimization suggested an optimal formula with desirability value of 0.852 and low prediction errors. The optimized formulation showed good % drug entrapment efficiency (79.56 ± 2.34%), nanometer size (56.68 ± 1.2 nm), monodisperse nature (PDI = 0.176 ± 0.2), spherical morphology and good drug-excipient compatibility. The raloxifene hydrochloride loaded lipid nanocapsule hydrogel showed shear thinning properties, sustained drug delivery, dermal compatibility and significantly higher permeability (2-fold), retention (3.37) for raloxifene hydrochloride compared to the control.

CONCLUSION

The present study showed a successful development of raloxifene hydrochloride loaded lipid nanocapsule hydrogel with improved skin permeation, retention, and good topical compatibility. This formulation may overcome the challenges associated with raloxifene hydrochloride oral delivery including low bioavailability.

Limosilactobacillus reuteri DSM 17938 Inhibition of Biofilm Formation by Prevotella intermedia and Fusobacterium nucleatum Across Salivary pH: An In Vitro Study

OBJECTIVES

 This study aims to investigate Limosilactobacillus reuteri DSM 17938's antibiofilm effects on Prevotella intermedia and Fusobacterium nucleatum, common causes of alveolar osteitis. It seeks topical alternatives to prevent this condition posttooth extraction. The secondary objective is to assess these effects under different pH conditions (pH 4.5 and pH 7), mimicking oral cavity saliva pH dynamics.

MATERIALS AND METHODS

 Ethical approval was secured for the saliva collection process involving five healthy adult participants who had undergone wisdom tooth extraction. Saliva samples were diligently collected on the 7th day post-surgery. The unstimulated saliva underwent a series of treatments, including the addition of phenylmethylsulfonyl fluoride (PMSF), pH adjustments, centrifugation, and filtration. The pH levels were re-measured, and subsequent adjustments were made to achieve pH values of 4.5 or 7. Limosilactobacillus reuteri DSM 17938, with a concentration of 1×108 colony-forming units (CFU) per 5 drops, was utilized in the study. Biofilm testing involved incubating saliva samples with varying pH (4.5 or 7) alongside bacterial suspensions (Prevotella intermedia, Fusobacterium nucleatum, or a mixed species). The Interlac suspension was introduced, and plates were anaerobically incubated for 24 hours. Biofilm results were obtained using a spectrometer. The test is conducted in triplicate.

STATISTICAL ANALYSIS

 To scrutinize the impact of pH on biofilm development, the acquired data underwent a two-way ANOVA test in SPSS as part of the statistical analysis. A significance level of p<0.05 was used to determine statistical significance.

RESULTS

 Limosilactobacillus reuteri DSM 17938 significantly reduced biofilm formation across bacterial strains (p = 0.000). Statistical analysis indicated a significant impact of pH on biofilm development (p = 0.000) compared to no saliva samples, with higher formation observed under acidic conditions (pH 4.5). However, the pH levels of 4.5 and 7 did not result in significantly different bacterial biofilm formation (p = 0.529).

CONCLUSION

 This research highlights Limosilactobacillus reuteri DSM 17938's potency in inhibiting biofilm formation of Prevotella intermedia and Fusobacterium nucleatum. Salivary pH variations significantly influence biofilm development, emphasizing the need to consider pH when assessing probiotic effectiveness. Despite limitations in saliva sample sterilization, this study provides valuable insights into alternative approaches for preventing alveolar osteitis. Further research should explore clinical applications and refine sterilization methods for more accurate results.

A review on polysaccharide-based delivery systems for edible bioactives: pH responsive, controlled release, and emerging applications

pH changes occur during bodily lesions, presenting an opportunity for leveraging pH-responsive delivery systems as signals for a targeted response. This review explores the design and application of pH-responsive delivery systems based on natural polysaccharides for the controlled release of bioactives. The article examines the development of diverse delivery carriers, including nanoparticles, nanofibers, nanogels, core-shell carriers, hydrogels, emulsions as well as liposomes and their capacity to respond to pH variations, enabling the precise and targeted delivery of bioactives within the human body. These polysaccharide-based delivery systems can be made pH-responsive by modulating the charge of polybasic or polyacidic polysaccharides, inducing swelling of the carrier and subsequent release of the encapsulated bioactives. These pH-responsive systems show promise in stabilizing under acidic conditions for enhanced retention in the stomach during oral delivery while also enabling targeted release at low pH sites such as tumors and wounds, thereby accelerating wound healing and aiding in cancer therapy and inflammation treatment. pH can co-respond with a variety of stimuli, including temperature, enzymes and reactive oxygen species, enabling more precise responses to the microenvironment for targeted delivery. It provides solid theoretical foundations for the advancement of personalized nutrition and therapeutics through controlled and responsive release technologies.

Development of Dermal Lidocaine Nanosuspension Formulation by the Wet Milling Method Using Experimental Design: In Vitro/In Vivo Evaluation

Lidocaine (LID), frequently used in dermal applications, is a nonpolar local anesthetic agent that is practically insoluble in water. The main aim of this study is to develop the nanosuspension formulation of LID using the design of experiments (DoE). The improved solubility and dissolution rate provided by nanosizing are expected to result in enhanced dermal bioavailability. Nanosuspension formulations were developed by a wet media milling method using different stabilizer types [poloxamer (POL) and poly(vinyl alcohol) (PVA)]. Characterization studies of the nanosuspensions were carried out using DSC, FTIR, XRD, and SEM in vitro release from the dialysis membrane and ex vivo permeation studies using rat skin were performed. Analgesic/anesthetic effects were evaluated using the tail-flick test in in vivo studies. Particle size (PS), polydispersity index (PDI), and zeta potential (ZP) values were found as 171.7 ± 3.52 nm, 0.251 ± 0.036, and -32.2 ± 0.907 mV for POL/LID nanosuspensions and 262.1 ± 29.42 nm, 0.453 ± 0.071, and -20.2 ± 3.50 mV for PVA/LID nanosuspensions, respectively. Compared to the coarse suspension of LID, it was determined that it accumulated in the skin approximately 1.81 times more in the POL/LID nanosuspension formulation and 1.79 times more in the PVA/LID nanosuspension formulation. According to analgesic effect and related AUC data, nanosuspension formulation was found to be statistically more effective than coarse suspension. It is concluded that DoE is a useful tool in determining process parameters when developing nanosuspensions by the wet media milling method, and POL is a suitable nonionic polymer to stabilize nanosuspensions.

The role of responsive MRI probes in the past and the future of molecular imaging

Magnetic resonance imaging (MRI) has become an indispensable tool in biomedical research and clinical radiology today. It enables the tracking of physiological changes noninvasively and allows imaging of specific biological processes at the molecular or cellular level. To this end, bioresponsive MRI probes can greatly contribute to improving the specificity of MRI, as well as significantly expanding the scope of its application. A large number of these sensor probes has been reported in the past two decades. Importantly, their development was done hand in hand with the ongoing advances in MRI, including emerging methodologies such as chemical exchange saturation transfer (CEST) or hyperpolarised MRI. Consequently, several approaches on successfully using these probes in functional imaging studies have been reported recently, giving new momentum to the field of molecular imaging, also the chemistry of MRI probes. This Perspective summarizes the major strategies in the development of bioresponsive MRI probes, highlights the major research directions within an individual group of probes (T 1- and T 2-weighted, CEST, fluorinated, hyperpolarised) and discusses the practical aspects that should be considered in designing the MRI sensors, up to their intended application in vivo.

Emerging Role of Extracellular pH in Tumor Microenvironment as a Therapeutic Target for Cancer Immunotherapy

Identifying definitive biomarkers that predict clinical response and resistance to immunotherapy remains a critical challenge. One emerging factor is extracellular acidosis in the tumor microenvironment (TME), which significantly impairs immune cell function and contributes to immunotherapy failure. However, acidic conditions in the TME disrupt the interaction between cancer and immune cells, driving tumor-infiltrating T cells and NK cells into an inactivated, anergic state. Simultaneously, acidosis promotes the recruitment and activation of immunosuppressive cells, such as myeloid-derived suppressor cells and regulatory T cells (Tregs). Notably, tumor acidity enhances exosome release from Tregs, further amplifying immunosuppression. Tumor acidity thus acts as a "protective shield," neutralizing anti-tumor immune responses and transforming immune cells into pro-tumor allies. Therefore, targeting lactate metabolism has emerged as a promising strategy to overcome this barrier, with approaches including buffer agents to neutralize acidic pH and inhibitors to block lactate production or transport, thereby restoring immune cell efficacy in the TME. Recent discoveries have identified genes involved in extracellular pH (pHe) regulation, presenting new therapeutic targets. Moreover, ongoing research aims to elucidate the molecular mechanisms driving extracellular acidification and to develop treatments that modulate pH levels to enhance immunotherapy outcomes. Additionally, future clinical studies are crucial to validate the safety and efficacy of pHe-targeted therapies in cancer patients. Thus, this review explores the regulation of pHe in the TME and its potential role in improving cancer immunotherapy.

pH-dependent binding of ATP aptamer to the target and competition strands: Fluorescent melting curve fitting study

The pH varies in different tissues and organelles and also changes during some diseases. In this regard, the application of molecular switches that use a competition-based aptamer switch design in biological systems requires studying the thermodynamics of such systems at different pH values. In this work, we studied the binding of the classical ATP aptamer to ATP and competition strands under different pH and ionic conditions using fluorescent melting curve analysis. We have developed an original approach to processing source data from a PCR thermal cycler. It is based on constructing a thermodynamic model of the melting profile and the subsequent fit of experimental curves within this model. We have shown that this approach enables us to narrow the temperature region under study to the width of the melting region without a significant loss in the quality of the result. This impressively expands the application area of this approach compared to frequently used techniques that require mandatory measurement of the signal outside the melting region. The results obtained by the method showed that the thermodynamic parameters of the ATP aptamer and its duplexes with competition strands change depending on pH. Therefore, molecular switches that use a competition strand to the ATP aptamer may have a pH-dependent sensitivity that has not been previously considered. This should be taken into account for future rational design of similar systems.

Ultralow Power, Cleft Size-Adjustable and pH-Sensitive Hyaluronic Acid (HA) Biodevices for Acid-Sensing Ion Channels Emulation

The burgeoning implantable biodevices have unlocked new frontiers in healthcare, promising personalized monitoring strategies tailored to specific needs. Herein, hyaluronic acid (HA) is harnessed to create fully biocompatible, acidity-sensitivity and cleft-adjustable neuromorphic devices. These HA-biodevices exhibit remarkable sensitivity to pH variations, effectively mimicking biological acid-sensing ion channels (ASICs) through protonation reactions between electronegative atoms and hydrogen ions, even at ultralow driving voltage (5 mV). They can monitor joint cartilage acidity by tracking changes in proton concentration and successfully diagnose the onset of arthritis. Furthermore, by adjusting the synaptic device's cleft distance, which determines responsiveness, power efficiency and plasticity, HA-based neuromorphic devices can be tailored to meet the unique demands of various implantation sites, providing both high-sensitivity and low-heat dissipation, thus broadening their application scopes. Moreover, the HA-biodevices maintain stable performance across various bending degrees, up to a curvature radius of 7.5 mm, with flexibility and deformation resilience enabling installation on joints of varying curvatures. The combination of all-biocompatibility, high sensitivity, low heat dissipation, ultralow low power (2 pW), and extraordinary deformation tolerance paves the way for the development of versatile, multipurpose medical monitoring devices with immense potential in the field of healthcare.

Exploring Nanocarriers for Boosting Entacapone Bioavailability: A Journey through System Characterization and Assessment of Toxicity and Pharmacological and 2D Permeability Paybacks

Catechol-O-methyltransferase inhibitors (iCOMT), such as entacapone, have been successfully employed to treat tremor-related symptoms of Parkinson's disease. However, iCOMT has been associated with a short half-life and poor oral bioavailability. Nanobased drug delivery systems have often been used to overcome this type of setbacks. Therefore, entacapone was encapsulated in PEGylated poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles (NPs) via a nanoprecipitation process, as well as in PEGylated nanostructured lipid carriers (NLCs) using a solvent emulsification/evaporation method. Both nanoformulations presented sub-200 nm populations, with zeta-potential (ZP) values close to -30 mV, and showed stability at different pHs, while maintaining their physicochemical properties mostly intact, presenting only a change in their superficial charge (ZP values), indicating their interaction. Both nanoformulations presented interaction with mucins, which anticipates good permeation and bioavailability for oral and topical administration. No cytotoxic effects were observed for lyophilized PLGA NPs encapsulating entacapone, in which 2-hydroxypropyl-ß-cyclodextrin (HPβCD) was used as a cryoprotectant at 3% concentration (HP-PLGA@Ent), in human hepatocellular carcinoma (HepG2), human neuroblastoma (SH-SY5Y), or human epithelial colorectal adenocarcinoma (Caco-2) cell lines. Conversely, NLCs encapsulating entacapone (W-NLCs@Ent) presented cytotoxic effects on the HepG2 cell line, likely due to intracellular lipid accumulation or storage. Both nanoformulations maintained a COMT inhibition effect in HepG2 cells, using 3-BTD as the COMT probe. An increase of entacapone permeability in both monolayer and coculture models (Caco-2 and Caco-2/HT29-MTX, respectively) was observed for the developed nanoformulations. Overall, this work shows that encapsulated entacapone in different nanocarriers could be a stimulating alternative to solve entacapone setbacks, since they improve its physicochemical properties and permeability while still maintaining the COMT inhibitory activity.

Advancements in Colon-Targeted Drug Delivery: A Comprehensive Review on Recent Techniques with Emphasis on Hot-Melt Extrusion and 3D Printing Technologies

This review investigates the progression and effectiveness of colon-targeted drug delivery systems, offering a comprehensive understanding of the colon's anatomy and physiological environment. Recognizing the distinctive features of the colon is crucial for successfully formulating oral dosage forms that precisely target specific areas in the gastrointestinal tract (GIT) while minimizing side effects through mitigating off-target sites. This understanding forms the basis for designing effective targeted drug delivery systems. The article extensively examines diverse approaches to formulating drugs for colonic targeting, highlighting key polymers and excipients in their production. Special emphasis is given to innovative approaches such as hot-melt extrusion (HME) and three-dimensional printing (3D-P), renowned for their accuracy in drug release kinetics and intricate dosage form geometry. However, challenges arise regarding material standardization and the complex network of regulatory clearances required to confirm safety and effectiveness. The review provides insights into each application's advantages and potential challenges. Furthermore, it sheds light on the local diseases that necessitate colon targeting and the available marketed products, providing an overview of the current state of colon-targeted drug delivery systems. Additionally, the review emphasizes the importance of testing drugs in a controlled in vitro environment during the development phase. It also discusses the future directions for successful development in this field. By integrating knowledge across anatomy, formulation techniques, and assessment methodologies, this review is a valuable resource for researchers navigating the dynamic field of colonic drug delivery.

Stimuli-Responsive Molecularly Imprinted Polymers: Mechanism and Applications

Molecularly imprinted polymers (MIPs) are very suitable for extraction, drug delivery systems, and sensors due to their good selective adsorption ability, but the difficulty of eluting templates during synthesis and the limitation of application scenarios put higher demands on MIPs. Stimuli-responsive MIPs (SR-MIPs) can actively respond to changes in external conditions to realize various functions, which provides new ideas for the further development of MIPs. This paper reviews the multiple response modes of MIPs, including the common temperature, pH, photo, magnetic, redox-responsive and rare gas, biomolecule, ion, and solvent-responsive MIPs, and explains the mechanism, composition, and applications of such SR-MIPs. These SR-MIPs and the resulting dual/multiple-responsive MIPs have good selectivity, and controllability, and are very promising for isolation and extraction, targeted drug delivery, and electro-sensor.

Doxorubicin-loaded liposome-like particles embedded in chitosan/hyaluronic acid-based hydrogels as a controlled drug release model for local treatment of glioblastoma

Glioblastoma (GBM) resection and medication treatment are limited, and local drug therapies are required. This study aims to create a hybrid system comprising liposome-like particles (LLP-DOX) encapsulated in chitosan/hyaluronic acid/polyethyleneimine (CHI/HA/PEI) hydrogels, enabling controlled local delivery of doxorubicin (DOX) into the resection cavity for treating GBM. CHI/HA/PEI hydrogels were characterized morphologically, physically, chemically, mechanically, and thermally. Findings revealed a high network and compact micro-network structure, along with enhanced physical and thermal stability compared to CHI/HA hydrogels. Simultaneously, drug release from CHI/HA/PEI/LLP-DOX hydrogels was assessed, revealing continuous and controlled release up to the 148th hour, with no significant burst release. Cell studies showed that CHI/HA/PEI hydrogels are biocompatible with low genotoxicity. Additionally, LLP-DOX-loaded CHI/HA/PEI hydrogels significantly decreased cell viability and gene expression levels compared to LLP-DOX alone. It was also observed that the viability of GBM spheroids decreased over time when interacting with CHI/HA/PEI/LLP-DOX hydrogels, accompanied by a reduction in total surface area and an increase in apoptotic tendencies. In this study, we hypothesized that creating a hybrid drug delivery system by encapsulating DOX-loaded LLPs within a CHI/HA/PEI hydrogel matrix could achieve sustained drug release, improve anticancer efficacy via localized treatment, and effectively mitigate GBM progression for 3D microtissues.

Temporal Dynamics of Pain: Examining the Relationship Between Intramuscular Injection Duration and Pain Perception: A Crossover Randomized Controlled Trial

Background Effective pain management is crucial for optimizing the patient experience and satisfaction with care. Many factors affect the intensity of injection pain, and one of these factors is the duration of the injection. This study aimed to evaluate the impact of intramuscular injection duration on perceived pain intensity in adults. Methods Fifty participants received injections according to a predetermined research protocol. Each participant served as their own control group. The intervention group was administered the drug over 40 seconds. The control group was given the same drug on the other side dorsogluteal region the following day, according to the unit's routine, in 10 seconds. Pain intensity was measured using the Wong-Baker Faces Pain Rating Scale and the Numerical Rating Scale. Statistical analysis was performed using SPSS (IBM Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp), including Wilcoxon and correlation analyses, with a significance level set at p < 0.05. Results The Wilcoxon test revealed a significant decrease in pain scores for the intervention group (p < 0.05), indicating that longer injection durations were associated with lower pain intensity. Significant correlations were found between hospital phobia and the use of pain relief measures, with pain perception (p < 0.05). Conclusion This research establishes a correlation between extended durations of intramuscular injections and pain intensity. These findings have implications for pain management during medical procedures and can contribute to optimizing patient comfort.

Single-cell encapsulation systems for probiotic delivery: Armor probiotics

Functional foods or drugs based on probiotics have gained unprecedented attention and development due to the increasingly clear relationship between probiotics and human health. Probiotics can regulate intestinal microbiota, dynamically participating in various physiological activities to directly affect human health. Some probiotic-based functional preparations have shown great potential in treating multiple refractory diseases. Currently, the survival and activity of probiotic cells in complex environments in vitro and in vivo have taken priority, and various encapsulation systems based on food-derived materials have been designed and constructed to protect and deliver probiotics. However, traditional encapsulation technology cannot achieve precise protection for a single probiotic, which makes it unable to have a significant effect after release. In this case, single-cell encapsulation systems can be assembled based on biological interfaces to protect and functionalize individual probiotic cells, maximizing their physiological activity. This review discussed the arduous challenges of probiotics in food processing, storage, human digestion, and the commonly used probiotic encapsulation system. Besides, a novel technology of probiotic encapsulation was introduced based on single-cell coating, namely, "armor probiotics". We focused on the classification, structural design, and functional characteristics of armor coatings, and emphasized the essential functional characteristics of armor probiotics in human health regulation, including regulating intestinal health and targeted bioimaging and treatment of diseased tissues. Subsequently, the benefits, limitations, potential challenges, as well as future direction of armor probiotics were put forward. We hope this review may provide new insights and ideas for developing a single-cell probiotics encapsulating system.

Revealing the pH-dependent conformational changes in sol g 2.1 protein and potential ligands binding

Sol g 2, a major protein found in the venom of the tropical fire ant (Solenopsis geminata), is well-known for its ability to bind various hydrophobic molecules. In this study, we investigate the binding activity of recombinant Sol g 2.1 protein (rSol g 2.1) with potential molecules, including (E)-β-Farnesene, α-Caryophyllene, and 1-Octen-3-ol at different pH levels (pH 7.4 and 5.5) using fluorescence competitive binding assays (FCBA). Our results revealed that Sol g 2.1 protein has higher affinity binding with these ligands at neutral pH. Relevance to molecular docking and molecular dynamics simulations were utilized to provide insights into the stability and conformational dynamics of Sol g 2.1 and its ligand complexes. After simulation, we found that Sol g 2.1 protein has higher affinity binding with these ligands as well as high structural stability at pH 7.4 than at an acidic pH level, indicating by RMSD, RMSF, Rg, SASA, and principal component analysis (PCA). Additionally, the Sol g 2.1 protein complexes at pH 7.4 showed significantly lower binding free energy (∆Gbind) and higher total residue contributions, particularly from key non-polar amino acids such as Trp36, Met40, Cys62, and Ile104, compared to the lower pH environment. These explain why they exhibited higher binding affinity than the lower pH. Therefore, we suggested that Sol g 2.1 protein is a pH-responsive carrier protein. These findings also expand our understanding of protein-ligand interactions and offer potential avenues for the development of innovative drug delivery strategies targeting Sol g 2.1 protein.

Molecular understanding of the self-assembly of an N-isopropylacrylamide delivery system for the loading and temperature-dependent release of curcumin

Global changes and drug abuse are forcing humanity to face various disease problems, and alternative therapies with safe natural substances have important research value. This paper combines various techniques in quantum chemical calculations and molecular simulations to provide molecular-level insight into the dynamics of the self-assembly of N-isopropylacrylamide (NIPAM) for loading curcumin (CUR). The results indicate that increasing the chain length of NIPAM molecules reduces their efficiency in encapsulating and locking CUR, and electrostatic interactions and van der Waals interactions are the main driving forces behind the evolution of system configurations in these processes. The isopropyl groups of NIPAM and the two phenolic ring planes of CUR are the main contact areas for the interaction between the two types of molecules. The thermosensitive effect of NIPAM can alter the distribution of isopropyl groups in NIPAM molecules around CUR. As a result, when the temperature rises from ambient temperature (300 K) to human characteristic temperature (310 K), the NIPAM-CUR interactions and radial distribution functions suggest that body temperature is more suitable for drug release. Our findings offer a vital theoretical foundation and practical guidance for researchers to develop temperature-sensitive drug delivery systems tailored for CUR, addressing its clinical application bottleneck.

Development of Clindamycin-Releasing Polyvinyl Alcohol Hydrogel with Self-Healing Property for the Effective Treatment of Biofilm-Infected Wounds

Self-healing hydrogels have good mechanical strength, can endure greater external force, and have the ability to heal independently, resulting in a strong bond between the wound and the material. Bacterial biofilm infections are life-threatening. Clindamycin (Cly) can be produced in the form of a self-healing hydrogel preparation. It is noteworthy that the antibacterial self-healing hydrogels show great promise as a wound dressing for bacterial biofilm infection. In this study, we developed a polyvinyl alcohol/borax (PVA/B) self-healing hydrogel wound dressing that releases Cly. Four ratios of PVA, B, and Cly were used to make self-healing hydrogels: F1 (4%:0.8%:1%), F2 (4%:1.2%:1%), F3 (1.6%:1%), and F4 (4%:1.6%:0). The results showed that F4 had the best physicochemical properties, including a self-healing duration of 11.81 ± 0.34 min, swelling ratio of 85.99 ± 0.12%, pH value of 7.63 ± 0.32, and drug loading of 98.34 ± 11.47%. The B-O-C cross-linking between PVA and borax caused self-healing, according to FTIR spectra. The F4 formula had a more equal pore structure in the SEM image. The PVA/B-Cly self-healing hydrogel remained stable at 6 ± 2 °C for 28 days throughout the stability test. The Korsmeyer-Peppas model released Cly by Fickian diffusion. In biofilm-infected mouse wounds, PVA/B-Cly enhanced wound healing and re-epithelialization. Our results indicate that the PVA/B-Cly produced in this work has reliable physicochemical properties for biofilm-infected wound therapy.

Formulation and optimization of pH-sensitive nanocrystals for improved oral delivery

The challenge of low water solubility in pharmaceutical science profoundly impacts drug absorption and therapeutic effectiveness. Nanocrystals (NC), consisting of drug molecules and stabilizing agents, offer a promising solution to enhance solubility and control release rates. In the pharmaceutical industry, top-down techniques are favored for their flexibility and cost-effectiveness. However, increased solubility can lead to premature drug dissolution in the stomach, which is problematic due to the acidic pH or enzymes. Researchers are exploring encapsulating agents that facilitate drug release at customized pH levels as a valuable strategy to address this. This study employed wet milling and spray drying techniques to create encapsulated NC for delivering the drug to the intestinal tract using the model drug ivermectin (IVM). Nanosuspensions (NS) were efficiently produced within 2 h using NanoDisp®, with a particle size of 198.4 ± 0.6 nm and a low polydispersity index (PDI) of 0.184, ensuring uniformity. Stability tests over 100 days at 4 °C and 25 °C demonstrated practical viability, with no precipitation or significant changes observed. Cytotoxicity evaluations indicated less harm to Caco-2 cells compared to the pure drug. Furthermore, the solubility of the NC increased by 47-fold in water and 4.8-fold in simulated intestinal fluid compared to the pure active compound. Finally, dissolution tests showed less than 10% release in acidic conditions and significant improvement in simulated intestinal conditions, promising enhanced drug solubility and bioavailability. This addresses a long-standing pharmaceutical challenge in a cost-effective and scalable manner.

pH-Sensitive Amphiphilic Diblock Polyphosphoesters with Lactate Units: Synthesis and Application as Drug Carriers

pH-sensitive amphiphilic diblock polyphosphoesters containing lactic acid units were synthesized by multistep one-pot polycondensation reactions. They comprise acid-labile P(O)-O-C and C(O)-O-C bonds, the cleavage of which depends on the pH of the medium. The structure of these copolymers was characterized by 1H, 13C {H}, 31P NMR, and size exclusion chromatography (SEC). The newly synthesized polymers self-assembled into the micellar structure in an aqueous solution. The effects of the molecular weight of the copolymer and the length of the hydrophobic chain on micelle formation and stabilityand micelle size were studied via dynamic light scattering (DLS). Drug loading and encapsulation efficiency tests using doxorubicin revealed that hydrophobic drugs can be delivered by copolymers. It was established that the molecular weight of the copolymer, length of the hydrophobic chain and content of lactate units affects the size of the micelles, drug loading, and efficiency of encapsulation. A copolymer with 10.7% lactate content has drug loading (3.2 ± 0.3) and efficiency of encapsulation (57.4 ± 3.2), compared to the same copolymer with 41.8% lactate content (1.63%) and (45.8%), respectively. It was demonstrated that the poly[alkylpoly(ethylene glycol) phosphate-b-alkylpoly(ethylene glycol)lactate phosphate] DOX system has a pH-sensitive response capability in the result in which DOX was selectively accumulated into the tumor, where pH is acidic. The results obtained indicate that amphiphilic diblock polyphosphoesters have potential as drug carriers.

Printing a cure: A tailored solution for localized drug delivery in liver cancer treatment

Adjuvant chemotherapy is highly recommended for liver cancer to enhance survival rates due to its tendency to recur frequently. Localized drug-eluting implants have gained traction as an alternative to overcome the limitations of systemic chemotherapy. This work describes the development of biodegradable 3D printed (3DP) bilayer films loaded with 5-fluorouracil (5FU) and cisplatin (Cis) with different infill percentages where the 5FU layers were 40%, 30%, and 30% and Cis layers were 10%, 15%, and 10% for films A, B, and C, respectively. The relevant characterization tests were performed, and the drug content of films was 0.68, 0.50, and 0.50 mg of 5FU and 0.39, 0.80, and 0.34 mg of Cis for films A, B, and C, respectively. Cis release was affected by the alterations to the film design, where films A, B, and C showed complete release at 12, 14, and 23 days, respectively. However, 5FU was released over 24 h for all films. The films were stable for up to two weeks after storage at 25 °C/65% relative humidity and four weeks at 4 °C where drug content, tensile strength, FTIR, and thermal analysis results demonstrated negligible alterations. The cytotoxicity of the films was assessed by MTS assays using HepG2 cell lines demonstrating up to 81% reduction in cell viability compared to blank films. Moreover, apoptosis was confirmed by Western Blots and the determination of mitochondrial cell potential, highlighting the potential of these films as a promising approach in adjuvant chemotherapy.

The Effect of pH on the Viscoelastic Response of Alginate-Montmorillonite Nanocomposite Hydrogels

Ionically cross-linked alginate hydrogels are used in a wide range of applications, such as drug delivery, tissue engineering, and food packaging. A shortcoming of these gels is that they lose their strength and degrade at low pH values. To develop gels able to preserve their integrity in a wide range of pH values, Ca-alginate-montmorillonite nanocomposite gels are prepared, and their chemical structure, morphology, and mechanical response are analyzed. As the uniformity of nanocomposite gels is strongly affected by concentrations of MMT and CaCl2, it is revealed that homogeneous gels can be prepared with 4 wt.% MMT and 0.5 M CaCl2 at the highest. The viscoelastic behavior of nanocomposite gels in aqueous solutions with pH = 7 and pH = 2 is investigated by means of small-amplitude compressive oscillatory tests. It is shown that Ca-alginate-MMT nanocomposite gels preserve their integrity while being swollen at pH = 2. The experimental data are fitted by a model with only two material parameters, which shows that the elastic moduli increase linearly with a concentration of MMT at all pH values under investigation due to formation of physical bonds between alginate chains and MMT platelets. The presence of these bonds is confirmed by ATR-FTIR spectroscopy. The morphology of nanocomposite gels is studied by means of wide-angle X-ray diffraction, which reveals that intercalation of polymer chains between clay platelets increases the interlayer gallery spacing.

Structural and pKa Estimation of the Amphipathic HR1 in SARS-CoV-2: Insights from Constant pH MD, Linear vs. Nonlinear Normal Mode Analysis

A comprehensive understanding of molecular interactions and functions is imperative for unraveling the intricacies of viral protein behavior and conformational dynamics during cellular entry. Focusing on the SARS-CoV-2 spike protein (SARS-CoV-2 sp), a Principal Component Analysis (PCA) on a subset comprising 131 A-chain structures in presence of various inhibitors was conducted. Our analyses unveiled a compelling correlation between PCA modes and Anisotropic Network Model (ANM) modes, underscoring the reliability and functional significance of low-frequency modes in adapting to diverse inhibitor binding scenarios. The role of HR1 in viral processing, both linear Normal Mode Analysis (NMA) and Nonlinear NMA were implemented. Linear NMA exhibited substantial inter-structure variability, as evident from a higher Root Mean Square Deviation (RMSD) range (7.30 Å), nonlinear NMA show stability throughout the simulations (RMSD 4.85 Å). Frequency analysis further emphasized that the energy requirements for conformational changes in nonlinear modes are notably lower compared to their linear counterparts. Using simulations of molecular dynamics at constant pH (cpH-MD), we successfully predicted the pKa order of the interconnected residues within the HR1 mutations at lower pH values, suggesting a transition to a post-fusion structure. The pKa determination study illustrates the profound effects of pH variations on protein structure. Key results include pKa values of 9.5179 for lys-921 in the D936H mutant, 9.50 for the D950N mutant, and a slightly higher value of 10.49 for the D936Y variant. To further understand the behavior and physicochemical characteristics of the protein in a biologically relevant setting, we also examine hydrophobic regions in the prefused states of the HR1 protein mutants D950N, D936Y, and D936H in our study. This analysis was conducted to ascertain the hydrophobic moment of the protein within a lipid environment, shedding light on its behavior and physicochemical properties in a biologically relevant context.

Recent Progress in Stimuli-Responsive Antimicrobial Electrospun Nanofibers

Electrospun nanofibrous membranes have garnered significant attention in antimicrobial applications, owing to their intricate three-dimensional network that confers an interconnected porous structure, high specific surface area, and tunable physicochemical properties, as well as their notable capacity for loading and sustained release of antimicrobial agents. Tailoring polymer or hybrid-based nanofibrous membranes with stimuli-responsive characteristics further enhances their versatility, enabling them to exhibit broad-spectrum or specific activity against diverse microorganisms. In this review, we elucidate the pivotal advancements achieved in the realm of stimuli-responsive antimicrobial electrospun nanofibers operating by light, temperature, pH, humidity, and electric field, among others. We provide a concise introduction to the strategies employed to design smart electrospun nanofibers with antimicrobial properties. The core section of our review spotlights recent progress in electrospun nanofiber-based systems triggered by single- and multi-stimuli. Within each stimulus category, we explore recent examples of nanofibers based on different polymers and antimicrobial agents. Finally, we delve into the constraints and future directions of stimuli-responsive nanofibrous materials, paving the way for their wider application spectrum and catalyzing progress toward industrial utilization.

The Influence of an Isocyanate Structure on a Polyurethane Delivery System for 2'-Deoxycytidine-5'-monophosphate

The delivery of nucleosides represents an interesting research trend in recent years due to their application in various viral infections. The main aims of this study were to develop and to characterize polyurethane particles that are intended to be used for the transport of nucleosides. Three samples have been prepared using aliphatic diisocyanates, a mixture of polyethylene glycol, polycaprolactone, and diols, respectively. The samples were characterized through refractivity measurements, drug loading efficacy, release and penetration rate investigations, FTIR and Raman spectroscopy, thermal analyses, Zetasizer, SEM, HDFa cells viability, and irritation tests on mice skin. The results indicate the obtaining of particles with sizes between 132 and 190 nm, positive Zeta potential values (28.3-31.5 mV), and a refractivity index around 1.60. A good thermal stability was found, and SEM images show a medium tendency to agglomerate. The samples' color, pH, and electrical conductivity have changed only to a small extent over time, and the evaluations indicate an almost 70% encapsulation efficacy, a prolonged release, and that around 70% of particles have penetrated an artificial membrane in the first 24 h. The synthesized products should be tested in further clinical trials, and the current tests on cell cultures and mice skin revealed no side effects.

The improving strategies and applications of nanotechnology-based drugs in hepatocellular carcinoma treatment

Hepatocellular carcinoma (HCC) is one of the leading causes of tumor-related death worldwide. Conventional treatments for HCC include drugs, radiation, and surgery. Despite the unremitting efforts of researchers, the curative effect of HCC has been greatly improved, but because HCC is often found in the middle and late stages, the curative effect is still not satisfactory, and the 5-year survival rate is still low. Nanomedicine is a potential subject, which has been applied to the treatment of HCC and has achieved promising results. Here, we summarized the factors affecting the efficacy of drugs in HCC treatment and the strategies for improving the efficacy of nanotechnology-based drugs in HCC, reviewed the recent applications' progress on nanotechnology-based drugs in HCC treatment, and discussed the future perspectives and challenges of nanotechnology-based drugs in HCC treatment.

Factors associated with treatment failure, and possible applications of probiotic bacteria in the arsenal against Helicobacter pylori

INTRODUCTION

Helicobacter pylori is a widespread helical Gram-negative bacterium, which causes a variety of stomach disorders, such as peptic ulcer, chronic atrophic gastritis, and gastric cancer. This microbe frequently colonizes the mucosal layer of the human stomach and survives in the inhospitable microenvironment, by adapting to this hostile milieu.

AREAS COVERED

In this extensive review, we describe conventional antibiotic treatment regimens used against H. pylori including, empirical, tailored, and salvage therapies. Then, we present state-of-the-art information about reasons for treatment failure against H. pylori. Afterward, the latest advances in the use of probiotic bacteria against H. pylori infection are discussed. Finally, we propose a polymeric bio-platform to provide efficient delivery of probiotics for H. pylori infection.

EXPERT OPINION

For effective probiotic delivery systems, it is necessary to avoid the early release of probiotics at the acidic stomach pH, to protect them against enzymes and antimicrobials, and precisely target H. pylori bacteria which have colonized the antrum area of the stomach (basic pH).