Basic concepts and recent advances in nanogels as carriers for medical applications

Synthesis, characterization and stability of crosslinked chitosan-maltodextrin pH-sensitive nanogels

Polysaccharide-based nanogels offer a wide range of chemical compositions and are of great interest due to their biodegradability, biocompatibility, non-toxicity, and their ability to display pH, temperature, or enzymatic response. In this work, we synthesized monodisperse and tunable pH-sensitive nanogels by crosslinking, through reductive amination, chitosan and partially oxidized maltodextrins, by keeping the concentration of chitosan close to its overlap concentration, i.e. in the dilute and semi-dilute regime. The chitosan/maltodextrin nanogels presented sizes ranging from 63 ± 9 to 279 ± 16 nm, showed quasi-spherical and cauliflower-like morphology, reached a ζ-potential of +36 ± 2 mV and maintained a colloidal stability for up to 7 weeks. It was found that the size and surface charge of nanogels depended both on the oxidation degree of maltodextrins and chitosan concentration, as well as on its degree of acetylation and protonation, the latter tuned by pH. The pH-responsiveness of the nanogels was evidenced by an increased size, owed to swelling, and ζ-potential when pH was lowered. Finally, maltodextrin-chitosan biocompatible nanogels were assessed by cell viability assay performed using the HEK293T cell line.

Theranostic nanogels: multifunctional agents for simultaneous therapeutic delivery and diagnostic imaging

In recent years, there has been a growing interest in multifunctional theranostic agents capable of delivering therapeutic payloads while facilitating simultaneous diagnostic imaging of diseased sites. This approach offers a comprehensive strategy particularly valuable in dynamically evolving diseases like cancer, where combining therapy and diagnostics provides crucial insights for treatment planning. Nanoscale platforms, specifically nanogels, have emerged as promising candidates due to their stability, tunability, and multifunctionality as carriers. As a well-studied subgroup of soft polymeric nanoparticles, nanogels exhibit inherent advantages due to their size and chemical compositions, allowing for passive and active targeting of diseased tissues. Moreover, nanogels loaded with therapeutic and diagnostic agents can be designed to respond to specific stimuli at the disease site, enhancing their efficacy and specificity. This capability enables fine-tuning of theranostic platforms, garnering significant clinical interest as they can be tailored for personalized treatments. The ability to monitor tumor progression in response to treatment facilitates the adaptation of therapies according to individual patient responses, highlighting the importance of designing theranostic platforms to guide clinicians in making informed treatment decisions. Consequently, the integration of therapy and diagnostics using theranostic platforms continues to advance, offering intelligent solutions to address the challenges of complex diseases such as cancer. In this context, nanogels capable of delivering therapeutic payloads and simultaneously armed with diagnostic modalities have emerged as an attractive theranostic platform. This review focuses on advances made toward the fabrication and utilization of theranostic nanogels by highlighting examples from recent literature where their performances through a combination of therapeutic agents and imaging methods have been evaluated.

Functional Nanomaterials for the Treatment of Osteoarthritis

Osteoarthritis (OA) is the most common degenerative joint disease, affecting more than 595 million people worldwide. Nanomaterials possess superior physicochemical properties and can influence pathological processes due to their unique structural features, such as size, surface interface, and photoelectromagnetic thermal effects. Unlike traditional OA treatments, which suffer from short half-life, low stability, poor bioavailability, and high systemic toxicity, nanotherapeutic strategies for OA offer longer half-life, enhanced targeting, improved bioavailability, and reduced systemic toxicity. These advantages effectively address the limitations of traditional therapies. This review aims to inspire researchers to develop more multifunctional nanomaterials and promote their practical application in OA treatment.

O-carboxymethyl chitosan in biomedicine: A review

O-carboxymethyl chitosan (O-CMC) is a chitosan derivative produced through the substitution of hydroxyl (-OH) functional groups in glucosamine units with carboxymethyl (-CH2COOH) substituents, effectively addressing the inherent solubility issues of chitosan in aqueous solutions. O-CMC has garnered significant interest due to its enhanced solubility, elevated viscosity, minimal toxicity, and advantageous biocompatibility properties. Furthermore, O-CMC demonstrates antibacterial, antifungal, and antioxidant characteristics, rendering it a promising candidate for various biomedical uses such as wound healing, tissue engineering, anti-tumor therapies, biosensors, and bioimaging. Additionally, O-CMC is well-suited for the fabrication of nanoparticles, hydrogels, films, microcapsules, and tablets, offering opportunities for effective drug delivery systems. This review outlines the distinctive features of O-CMC, offers analyses of advancements and future potential based on current research, examines significant obstacles for clinical implementation, and foresees its ongoing significant impacts in the realm of biomedicine.

Fisetin-loaded pluronic-based nanogel: Radiation synthesis for alleviating neurocognitive impairments in a rat model of alzheimer's disease via modulation of the apoptotic cascade

Alzheimer's disease (AD) is a neurodegenerative disorder marked by cognitive impairment and memory loss. In this study, AD was experimentally induced in rats using aluminum chloride (AlCl3) and D-galactose (D-gal). Fisetin (Fis), a natural compound with antioxidant and anti-inflammatory properties, has potential for neurodegeneration management, but its low bioavailability limits clinical applications. To address this, we synthesized and characterized Pluronic-2-Acrylamido-2-methylpropane sulfonic acid (PLUR-PAMPS) nanogels using gamma radiation and successfully loaded Fis onto them (Fis-PLUR-PAMPS). The optimal formulation exhibited minimal particle size, a highly acceptable polydispersity index, and the highest zeta-potential, enhancing stability and solubilization efficiency. Our goal was to improve Fis's bioavailability and assess its efficacy against AlCl3/D-gal-induced AD. Male albino Wistar rats were pre-treated orally with Fis (40 mg/kg) or Fis-PLUR-PAMPS for seven days, followed by a seven-day intraperitoneal injection of AlCl3 and D-gal. Behavioral assessments, histopathological analysis, and biochemical evaluation of markers related to AD pathology were conducted. Results demonstrated that Fis-PLUR-PAMPS effectively mitigated cognitive impairments and neurodegenerative signs induced by AlCl3/D-gal. These findings suggest that Fis-PLUR-PAMPS nanogels enhance Fis's bioavailability and therapeutic efficacy, offering a promising approach for AD management.

Design and synthesis of drug hydrogels containing carboxymethylcellulose with honeycomb structure and pH-sensitivity as drug delivery systems for adriamycin, metformin, and naproxen

The aim of this research is to prepare and identify functionalized carboxymethylcellulose/mesoporous silica nanohydrogels (CMC/NH2-MCM-41) for obtaining a pH-sensitive system for the controlled release of drugs. The beads of CMC/NH2-MCM-41 nanocomposites were prepared by dispersing NH2-MCM-41 in a CMC polymer matrix and crosslinking with ferric ions (Fe3+). The SEM analysis of samples revealed enhancement in surface porosity of the functionalized nanohydrogel beads compared to the conventional beads. Swelling of the prepared functionalized nanohydrogels was evaluated at various pH values including pH = 7.35-7.45 (simulated body fluid or healthy cells), pH = 6 (simulated intestinal fluid), and pH = 1.5-3.5 (simulated gastric fluid). The swelling of CMC/MCM-41 and CMC/NH2-MCM-41 nanohydrogels at the pH values of simulated body fluid and simulated intestinal fluid is much higher than that of simulated gastric fluid, indicating successful synthesis of pH-sensitive nanohydrogels for drug delivery. The drug loading results showed that drug release in the CMC/NH2-MCM-41 system is much slower than that in the CMC/MCM-41 system. The results of the survival studies for the manufactured systems showed a very good biocompatibility of the designed drug delivery systems for biological applications. By coating the surface of functionalized mesopores with CMC hydrogel, we were able to develop a pH-sensitive intelligent drug delivery system.

Cancer Nanovaccines: Nanomaterials and Clinical Perspectives

Cancer nanovaccines represent a promising frontier in cancer immunotherapy, utilizing nanotechnology to augment traditional vaccine efficacy. This review comprehensively examines the current state-of-the-art in cancer nanovaccine development, elucidating innovative strategies and technologies employed in their design. It explores both preclinical and clinical advancements, emphasizing key studies demonstrating their potential to elicit robust anti-tumor immune responses. The study encompasses various facets, including integrating biomaterial-based nanocarriers for antigen delivery, adjuvant selection, and the impact of nanoscale properties on vaccine performance. Detailed insights into the complex interplay between the tumor microenvironment and nanovaccine responses are provided, highlighting challenges and opportunities in optimizing therapeutic outcomes. Additionally, the study presents a thorough analysis of ongoing clinical trials, presenting a snapshot of the current clinical landscape. By curating the latest scientific findings and clinical developments, this study aims to serve as a comprehensive resource for researchers and clinicians engaged in advancing cancer immunotherapy. Integrating nanotechnology into vaccine design holds immense promise for revolutionizing cancer treatment paradigms, and this review provides a timely update on the evolving landscape of cancer nanovaccines.

Design and applications of polymer-like peptides in biomedical nanogels

INTRODUCTION

Polymer nanogels are among the most promising nanoplatforms for use in biomedical applications. The substantial interest for these drug carriers is to enhance the transportation of bioactive substances, reduce the side effects, and achieve optimal action on the curative sites by targeting delivery and triggering the release of the drugs in a controlled and continuous mode.

AREA COVERED

The review discusses the opportunities, applications, and challenges of synthetic polypeptide nanogels in biomedicine, with an emphasis on the recent progress in cancer therapy. It is evidenced by the development of polypeptide nanogels for better controlled drug delivery and release, in complex in vivo microenvironments in biomedical applications.

EXPERT OPINION

Polypeptide nanogels can be developed by choosing the amino acids from the peptide structure that are suitable for the type of application. Using a stimulus - sensitive peptide nanogel, it is possible to obtain the appropriate transport and release of the drug, as well as to achieve desirable therapeutic effects, including safety, specificity, and efficiency. The final system represents an innovative way for local and sustained drug delivery at a specific site of the body.

Oligonucleotide based nanogels for cancer therapeutics

Oligonucleotide-based nanogels, as nascent biomaterials, possess several unique functional, structural, and physicochemical features with excellent drug-loading capacity and high potential for cancer gene therapy. Ongoing studies utilizing oligonucleotide-based nanogels hold great promise, as these cutting-edge nanoplatforms can be elegantly developed with predesigned oligonucleotide sequences and complementary strands which are self-assembled or chemically crosslinked leading to the development of nanogels with predictable shape and tunable size with the desired functional properties. Current paper provides a summary of the properties, preparation methods, and applications of oligonucleotide-based nanogels in cancer therapy. The review is focused on both conventional and modified forms of oligonucleotide-based nanogels, including targeted nanogels, smart release nanogels (responsive to stimuli such as pH, temperature, and enzymes), as well as nanogels used for gene delivery. Their application in cancer immunotherapy and vaccination, photodynamic therapy, and diagnostic applications when combined with other nanoparticles is further discussed. Despite emerging designs in the development of oligonucleotide based nanogels, this field of study is still in its infancy, and clinical translation of these versatile nano-vehicles might face challenges. Hence, extensive research must be performed on in vivo behavior of such platforms determining their biodistribution, biological fate, and acute/subacute toxicity.

Anticancer potential of thiocolchicoside and lauric acid loaded chitosan nanogel against oral cancer cell lines: a comprehensive study

The present study explored the anticancer activity of a Chitosan-based nanogel incorporating thiocolchicoside and lauric acid (CTL) against oral cancer cell lines (KB-1). Cell viability, AO/EtBr dual staining and Cell cycle analysis were done to evaluate the impact of CTL nanogel on oral cancer cells. Real-time PCR was performed to analyze proapoptotic and antiapoptotic gene expression in CTL-treated KB-1 cells. Further, molecular docking analysis was conducted to explore the interaction of our key ingredient, thiocolchicoside and its binding affinities. The CTL nanogel demonstrated potent anticancer activity by inhibiting oral cancer cell proliferation and inducing cell cycle arrest in cancer cells. Gene expression analysis indicated alterations in Bax and Bcl-2 genes; CTL nanogel treatment increased Bax mRNA expression and inhibited the Bcl-2 mRNA expression, which showed potential mechanisms of the CTL nanogel's anticancer action. It was found that thiocolchicoside can stabilize the protein's function or restore it as a tumour suppressor. The CTL nanogel exhibited excellent cytotoxicity and potent anticancer effects, making it a potential candidate for non-toxic chemotherapy in cancer nanomedicine. Furthermore, the nanogel's ability to modulate proapoptotic gene expression highlights its potential for targeted cancer therapy. This research contributes to the growing interest in Chitosan-based nanogels and their potential applications in cancer treatment.

Nanogels: Smart tools to enlarge the therapeutic window of gene therapy

Gene therapy can potentially treat a great number of diseases, from cancer to rare genetic disorders. Very recently, the development and emergency approval of nucleic acid-based COVID-19 vaccines confirmed its strength and versatility. However, gene therapy encounters limitations due to the lack of suitable carriers to vectorize therapeutic genetic material inside target cells. Nanogels are highly hydrated nano-size crosslinked polymeric networks that have been used in many biomedical applications, from drug delivery to tissue engineering and diagnostics. Due to their easy production, tunability, and swelling properties they have called the attention as promising vectors for gene delivery. In this review, nanogels are discussed as vectors for nucleic acid delivery aiming to enlarge gene therapy's therapeutic window. Recent works highlighting the optimization of inherent transfection efficiency and biocompatibility are reviewed here. The importance of the monomer choice, along with the internal structure, surface decoration, and responsive features are outlined for the different transfection modalities. The possible sources of toxicological endpoints in nanogels are analyzed, and the strategies to limit them are compared. Finally, perspectives are discussed to identify the remining challenges for the nanogels before their translation to the market as transfection agents.

Blood-brain barrier disruption in dementia: Nano-solutions as new treatment options

Candidate drugs targeting the central nervous system (CNS) demonstrate extremely low clinical success rates, with more than 98% of potential treatments being discontinued due to poor blood-brain barrier (BBB) permeability. Neurological conditions were shown to be the second leading cause of death globally in 2016, with the number of people currently affected by neurological disorders increasing rapidly. This increasing trend, along with an inability to develop BBB permeating drugs, is presenting a major hurdle in the treatment of CNS-related disorders, like dementia. To overcome this, it is necessary to understand the structure and function of the BBB, including the transport of molecules across its interface in both healthy and pathological conditions. The use of CNS drug carriers is rapidly gaining popularity in CNS research due to their ability to target BBB transport systems. Further research and development of drug delivery vehicles could provide essential information that can be used to develop novel treatments for neurological conditions. This review discusses the BBB and its transport systems and evaluates the potential of using nanoparticle-based delivery systems as drug carriers for CNS disease with a focus on dementia.

Chitosan/alginate nanogel potentiate berberine uptake and enhance oxidative stress mediated apoptotic cell death in HepG2 cells

Biopolymer-based nanoscale drug delivery systems have become a promising approach to overcome the limitations associated with conventional chemotherapeutics used for cancer treatment. Herein, we reported to develop a hydrophilic nanogel (NG) composed of Chitosan (Chi) and sodium alginate (Alg) using the ion gelation method for delivering Berberine hydrochloride (BBR), an alkaloid obtained from Berberis aristata roots. The use of different nanocarriers for BBR delivery has been reported previously, but the bioavailability of these carriers was limited due to phagocytic uptake and poor systemic delivery. The developed NG showed enhanced stability and efficient entrapment of BBR ∼92 %, resulting in a significant increase in bioavailability. The pH-dependent release behavior demonstrated sustained and effective release of ∼86 %, ∼74 % and, ∼53 % BBR at pH 5.5, 6.6, and 7.4 respectively after 72h, indicating its potential as a drug carrier. Additionally, the cellular uptake of BBR was significantly higher ∼19 % in the BBR-NG (25 μM) than in bulk BBR (100 μM), leading to enhanced ROS generation, mitochondrial depolarisation, and inhibition of cell proliferation and colony formation in HepG2 cells. In summary, the results suggest that the Chi/Alg biopolymer-based nano-formulation could be an effective approach for delivering BBR and enhancing its cellular uptake, efficacy, and cytotoxicity.

Smart nanogels for cancer treatment from the perspective of functional groups

Introduction: Cancer remains a significant health challenge, with chemotherapy being a critical treatment modality. However, traditional chemotherapy faces limitations due to non-specificity and toxicity. Nanogels, as advanced drug carriers, offer potential for targeted and controlled drug release, improving therapeutic efficacy and reducing side effects. Methods: This review summarizes the latest developments in nanogel-based chemotherapy drug delivery systems, focusing on the role of functional groups in drug loading and the design of smart hydrogels with controlled release mechanisms. We discuss the preparation methods of various nanogels based on different functional groups and their application in cancer treatment. Results: Nanogels composed of natural and synthetic polymers, such as chitosan, alginate, and polyacrylic acid, have been developed for chemotherapy drug delivery. Functional groups like carboxyl, disulfide, and hydroxyl groups play crucial roles in drug encapsulation and release. Smart hydrogels have been engineered to respond to tumor microenvironmental cues, such as pH, redox potential, temperature, and external stimuli like light and ultrasound, enabling targeted drug release. Discussion: The use of functional groups in nanogel preparation allows for the creation of multifunctional nanogels with high drug loading capacity, controllable release, and good targeting. These nanogels have shown promising results in preclinical studies, with enhanced antitumor effects and reduced systemic toxicity compared to traditional chemotherapy. Conclusion: The development of smart nanogels with functional group-mediated drug delivery and controlled release strategies represents a promising direction in cancer therapy. These systems offer the potential for improved patient outcomes by enhancing drug targeting and minimizing adverse effects. Further research is needed to optimize nanogel design, evaluate their safety and efficacy in clinical trials, and explore their potential for personalized medicine.

Recent advances in stimuli-responsive tailored nanogels for cancer therapy; from bench to personalized treatment

To improve the quality of health in a personalized manner, better control over pharmacologically relevant cargo formulation, organ-specific targeted delivery, and on-demand release of therapeutic agents is crucial. Significant work has been put into designing and developing revolutionary nanotherapeutics approaches for the effective monitoring and personalized treatment of disease. Nanogel (NG) has attracted significant interest because of its tremendous potential in cancer therapy and its environmental stimuli responsiveness. NG is considered a next-generation delivery technology due to its benefits like as size tunability, high loading, stimuli responsiveness, prolonged drug release via in situ gelling mechanisms, stability, and its potential to provide personalized therapy from the investigation of human genes and the genes in various types of cancers and its association with a selective anticancer drug. Stimuli-responsive NGs can be used as smart nanomedicines to detect and treat cancer and can be tuned as personalized medicine as well. This comprehensive review article's major objectives include the challenges of NGs' clinical translation for cancer treatment as well as its early preclinical successes and prospects.

Crosslinking kiwifruit-derived DNA with natural aromatic aldehydes generates membranolytic antibacterial nanogels

Improper use of antibiotics has led to the global rise of drug-resistant biofilm bacteria. Thus, researchers have been increasingly interested in green materials that are highly biocompatible and have low toxicity. Here, nanogels (NGs) with imine bonds were synthesized by crosslinking kiwifruit-derived DNA's primary amine and aromatic aldehydes (cuminaldehyde, p-anisaldehyde, or vanillin) under water-in-hexane emulsion processes. Transmission electron microscope showed that the NGs had spherical geometry with an average particle size ranging from 40 to 140 nm and that the zeta potential indicated a negative charge. Additionally, the DNA-aromatic aldehyde NGs showed low cytotoxicity toward normal cell organoids and human RBCs in cell viability tests. These NGs were also tested against four pathogenic bacteria for various assays. DNA-vanillin (DNA-VA) NGs exhibited significant antibacterial effects against bacteria with very low inhibitory concentrations as seen in a minimum inhibitory concentration assay. Scanning electron microscope observation revealed that the bacteria were deformed, and immunoblotting detected intracellular groEL protein expression. In agreement with these results, DNA-aromatic aldehyde NGs successfully protected C. elegans from P. aeruginosa-induced lethality. These DNA NGs provided a multivalent 3D space for antibacterial aromatic aldehydes to tether, enhancing their interaction with the bacterial wall. These results offer a new direction for the development of novel antibiotics in the future.

Bioconjugation Techniques for Enhancing Stability and Targeting Efficiency of Protein and Peptide Therapeutics

Bioconjugation techniques have emerged as powerful tools for enhancing the stability and targeting efficiency of protein and peptide therapeutics. This review provides a comprehensive analysis of the various bioconjugation strategies employed in the field. The introduction highlights the significance of bioconjugation techniques in addressing stability and targeting challenges associated with protein and peptide-based drugs. Chemical and enzymatic bioconjugation methods are discussed, along with crosslinking strategies for covalent attachment and site-specific conjugation approaches. The role of bioconjugation in improving stability profiles is explored, showcasing case studies that demonstrate successful stability enhancement. Furthermore, bioconjugation techniques for ligand attachment and targeting are presented, accompanied by examples of targeted protein and peptide therapeutics. The review also covers bioconjugation approaches for prolonging circulation and controlled release, focusing on strategies to extend half-life, reduce clearance, and design-controlled release systems. Analytical characterization techniques for bioconjugates, including the evaluation of conjugation efficiency, stability, and assessment of biological activity and targeting efficiency, are thoroughly examined. In vivo considerations and clinical applications of bioconjugated protein and peptide therapeutics, including pharmacokinetic and pharmacodynamic considerations, as well as preclinical and clinical developments, are discussed. Finally, the review concludes with an overview of future perspectives, emphasizing the potential for novel conjugation methods and advanced targeting strategies to further enhance the stability and targeting efficiency of protein and peptide therapeutics.

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.

Nanogels with covalently bound and releasable trehalose for autophagy stimulation in atherosclerosis

Atherosclerosis, cholesterol-driven plaque formation in arteries, is a complex multicellular disease which is a leading cause of vascular diseases. During the progression of atherosclerosis, the autophagic function is impaired, resulting in lipid accumulation-mediated foam cell formation. The stimulation of autophagy is crucial for the recovery of cellular recycling process. One of the potential autophagy inducers is trehalose, a naturally occurring non-reducing disaccharide. However, trehalose has poor bioavailability due to its hydrophilic nature which results in poor penetration through cell membranes. To enhance its bioavailability, we developed trehalose-releasing nanogels (TNG) for the treatment of atherosclerosis. The nanogels were fabricated through copolymerization of 6-O-acryloyl-trehalose with the selected acrylamide-type monomers affording a high trehalose conjugation (~ 58%, w/w). TNG showed a relatively small hydrodynamic diameter (dH, 67 nm) and a uniform spherical shape and were characterized by negative ζ potential (-18 mV). Thanks to the trehalose-rich content, TNG demonstrated excellent colloidal stability in biological media containing serum and were non-hemolytic to red blood cells. In vitro study confirmed that TNG could stimulate autophagy in foam cells and enhance lipid efflux and in vivo study in ApoE-/- mice indicated a significant reduction in atherosclerotic plaques, while increasing autophagic markers. In conclusion, TNG hold great promise as a trehalose delivery system to restore impaired autophagy-mediated lipid efflux in atherosclerosis and subsequently reduce atherosclerotic plaques.

Rational Design and Development of Polymeric Nanogels as Protein Carriers

Proteins have gained significant attention as potential therapeutic agents owing to their high specificity and reduced toxicity. Nevertheless, their clinical utility is hindered by inherent challenges associated with stability during storage and after in vivo administration. To overcome these limitations, polymeric nanogels (NGs) have emerged as promising carriers. These colloidal systems are capable of efficient encapsulation and stabilization of protein cargoes while improving their bioavailability and targeted delivery. The design of such delivery systems requires a comprehensive understanding of how the synthesis and formulation processes affect the final performance of the protein. This review highlights critical aspects involved in the development of NGs for protein delivery, with specific emphasis on loading strategies and evaluation techniques. For example, factors influencing loading efficiency and release kinetics are discussed, along with strategies to optimize protein encapsulation through protein-carrier interactions to achieve the desired therapeutic outcomes. The discussion is based on recent literature examples and aims to provide valuable insights for researchers working toward the advancement of protein-based therapeutics.

Regulation of cell fate by cell imprinting approach in vitro

Cell culture-based technologies are widely utilized in various domains such as drug evaluation, toxicity assessment, vaccine and biopharmaceutical development, reproductive technology, and regenerative medicine. It has been demonstrated that pre-adsorption of extracellular matrix (ECM) proteins including collagen, laminin and fibronectin provide more degrees of support for cell adhesion. The purpose of cell imprinting is to imitate the natural topography of cell membranes by gels or polymers to create a reliable environment for the regulation of cell function. The results of recent studies show that cell imprinting is a tool to guide the behavior of cultured cells by controlling their adhesive interactions with surfaces. Therefore, in this review we aim to compare different cell cultures with the imprinting method and discuss different cell imprinting applications in regenerative medicine, personalized medicine, disease modeling, and cell therapy.

Recent advances in immunomodulatory hydrogels biomaterials for bone tissue regeneration

There is a high incidence of fractures in clinical practice and therapy. The repairment of critical size defects in the skeletal system remains a huge challenge for surgeons and researchers, which can be overcame by the application of bone tissue-engineered biomaterials. An increasing number of investigations have revealed that the immune system plays a vital role in the repair of bone defects, especially macrophages, which can modulate the integration of biomaterials and bone regeneration in multiple ways. Therefore, it has become increasingly important in regenerative medicine to regulate macrophage polarization to prevent inflammation caused by biomaterial implantation. Recent studies have stressed the importance of hydrogel-based modifications and the incorporation of various cellular and molecular signals for regulating immune responses to promote bone tissue regeneration and integrate biomaterials. In this review, we first elaborate briefly on the described the general physiological mechanism and process of bone tissue regeneration. Then, we summarized the immunomodulatory role macrophages play in bone repair. In addition, the role of hydrogel-based immune modification targeting macrophage modulation in accelerating and enhancing bone tissue regeneration was also discussed. Finally, we highlighted future directions and research strategies related to hydrogel optimization for the regulation of the immune response during bone regeneration and healing.

Stimuli-Responsive and Multifunctional Nanogels in Drug Delivery

Nanogels represent promising drug delivery systems in the biomedical field, designed to overcome challenges associated with standard treatment approaches. Stimuli-responsive nanogels, often referred to as intelligent materials, have garnered significant attention for their potential to enhance control over properties such as drug release and targeting. Furthermore, researchers have recently explored the application of nanogels in diverse sectors beyond biomedicine including sensing materials, catalysts, or adsorbents for environmental applications. However, to fully harness their potential as practical delivery systems, further research is required to better understand their pharmacokinetic behaviour, interactions between nanogels and bio distributions, as well as toxicities. One promising future application of stimuli-responsive multifunctional nanogels is their use as delivery agents in cancer treatment, offering an alternative to overcome the challenges with conventional approaches. This review discusses various synthetic methods employed in developing nanogels as efficient carriers for drug delivery in cancer treatment. The investigations explore, the key aspects of nanogels, including their multifunctionality and stimuli-responsive properties, as well as associated toxicity concerns. The discussions presented herein aim to provide the readers a comprehensive understanding of the potential of nanogels as smart drug delivery systems in the context of cancer therapy.

Neural cell membrane-coated DNA nanogels as a potential target-specific drug delivery tool for the central nervous system

A major bottleneck in drug/gene delivery to enhance tissue regeneration after injuries is to achieve targeted delivery to the cells of interest. Unfortunately, we have not been able to attain effective targeted drug delivery in tissues due to the lack of efficient delivery platforms. Since specific cell-cell interactions exist to impart the unique structure and functionality of tissues and organs, we hypothesize that such specific cellular interactions may also be harnessed for drug delivery applications in the form of cell membrane coatings. Here, we employed neural cell-derived membrane coating technique on DNA nanogels to improve target specificity. The efficacy of neural cell membrane-coated DNA nanogels (NCM-nanogels) was demonstrated by using four types of cell membranes derived from the central nervous system (CNS), namely, astrocytes, microglia, cortical neurons, and oligodendrocyte progenitor cells (OPCs). A successful coating of NCMs over DNA nanogels was confirmed by dynamic light scattering, zeta potential measurements and transmission electron microscopy. Subsequently, an overall improvement in cellular uptake of NCM-nanogels over uncoated DNA nanogels (p < 0.005) was seen. Additionally, we observed a selective uptake of OPC membrane-coated DNA nanogels (NCM-O mem) by oligodendrocytes over other cell types both in vitro and in vivo. Our quantitative polymerase chain reaction (qPCR) results also showed selective and effective gene knockdown capacity of NCM-O mem for OPC transfection. The findings in this work may be beneficial for future drug delivery applications targeted at the CNS.

Double network structure via ionic bond and covalent bond of carboxymethyl chitosan and poly(ethylene glycol): Factors affecting hydrogel formation

The factors were studied that affect the formation of DN hydrogel, which was prepared using a water-based, environmental-friendly system. The DN hydrogel was designed and prepared based on a cross-linked, polysaccharide-based, polymer carboxymethyl chitosan (CMCS) via an ionic crosslinking reaction for the first network structure. UV irradiation created a radical crosslinking reaction of poly(ethylene glycol) from a double bond at the chain end for the second network structure. It was found that the optimum hydrogel was produced using 9.5 %v/v of 1000PEGGMA, CMCS 5%w/v, and CaCl₂ 3%w/v. The results showed the highest percentage of the gel fraction was 87.84 % and the hydrogel was stable based on its rheological properties. Factors affecting the hydrogel formation were the concentration and molecular weight of PEGGMA and the concentrations of CMCS and calcium chloride (CaCl₂). The DN hydrogel had bioactivity due to its octacalcium phosphate (OCP) hydroxyapatite crystal form. In addition, the composite DN scaffold with a conductive polymer of chitosan-grafted-polyaniline (CS-g-PANI) had conduction of 2.33 × 10^-5 S/cm when the concentration of CS-g-PANI was 3 mg/ml, confirming the semi-conductive nature of the material. All the results indicated that DN hydrogel could be a candidate to apply in tissue-engineering applications.

Current Overview of Metal Nanoparticles' Synthesis, Characterization, and Biomedical Applications, with a Focus on Silver and Gold Nanoparticles

Metal nanoparticles (NPs) have garnered considerable attention, due to their unique physicochemical properties, that render them promising candidates for various applications in medicine and industry. This article offers a comprehensive overview of the most recent advancements in the manufacturing, characterization, and biomedical utilization of metal NPs, with a primary focus on silver and gold NPs. Their potential as effective anticancer, anti-inflammatory, and antimicrobial agents, drug delivery systems, and imaging agents in the diagnosis and treatment of a variety of disorders is reviewed. Moreover, their translation to therapeutic settings, and the issue of their inclusion in clinical trials, are assessed in light of over 30 clinical investigations that concentrate on administering either silver or gold NPs in conditions ranging from nosocomial infections to different types of cancers. This paper aims not only to examine the biocompatibility of nanomaterials but also to emphasize potential challenges that may limit their safe integration into healthcare practices. More than 100 nanomedicines are currently on the market, which justifies ongoing study into the use of nanomaterials in medicine. Overall, the present review aims to highlight the potential of silver and gold NPs as innovative and effective therapeutics in the field of biomedicine, citing some of their most relevant current applications.

Vascular endothelial growth factor (VEGF) delivery approaches in regenerative medicine

The utilization of growth factors in the process of tissue regeneration has garnered significant interest and has been the subject of extensive research. However, despite the fervent efforts invested in recent clinical trials, a considerable number of these studies have produced outcomes that are deemed unsatisfactory. It is noteworthy that the trials that have yielded the most satisfactory outcomes have exhibited a shared characteristic, namely, the existence of a mechanism for the regulated administration of growth factors. Despite the extensive exploration of drug delivery vehicles and their efficacy in delivering certain growth factors, the development of a reliable predictive approach for the delivery of delicate growth factors like Vascular Endothelial Growth Factor (VEGF) remains elusive. VEGF plays a crucial role in promoting angiogenesis; however, the administration of VEGF demands a meticulous approach as it necessitates precise localization and transportation to a specific target tissue. This process requires prolonged and sustained exposure to a low concentration of VEGF. Inaccurate administration of drugs, either through off-target effects or inadequate delivery, may heighten the risk of adverse reactions and potentially result in tumorigenesis. At present, there is a scarcity of technologies available for the accurate encapsulation of VEGF and its subsequent sustained and controlled release. The objective of this review is to present and assess diverse categories of VEGF administration mechanisms. This paper examines various systems, including polymeric, liposomal, hydrogel, inorganic, polyplexes, and microfluidic, and evaluates the appropriate dosage of VEGF for multiple applications.

Macro, Micro, and Nano-Inspired Bioactive Polymeric Biomaterials in Therapeutic, and Regenerative Orofacial Applications

Introducing dental polymers has accelerated biotechnological research, advancing tissue engineering, biomaterials development, and drug delivery. Polymers have been utilized effectively in dentistry to build dentures and orthodontic equipment and are key components in the composition of numerous restorative materials. Furthermore, dental polymers have the potential to be employed for medication administration and tissue regeneration. To analyze the influence of polymer-based investigations on practical medical trials, it is required to evaluate the research undertaken in this sector. The present review aims to gather evidence on polymer applications in dental, oral, and maxillofacial reconstruction.

Zwitterion-Modified Nanogel Responding to Temperature and Ionic Strength: A Dissipative Particle Dynamics Simulation

The self-assembly and stimuli-responsive properties of nanogel poly(n-isopropylacrylamide) (p(NIPAm)) and zwitterion-modified nanogel poly(n-isopropylacrylamide-co-sulfobetainemethacrylate) (p(NIPAm-co-SBMA)) were explored by dissipative particle dynamics simulations. Simulation results reveal that for both types of nanogel, it is beneficial to form spherical nanogels at polymer concentrations of 5-10%. When the chain length (L) elongates from 10 to 40, the sizes of the nanogels enlarge. As for the p(NIPAm) nanogel, it shows thermoresponsiveness; when it switches to the hydrophilic state, the nanogel swells, and vice versa. The zwitterion-modified nanogel p(NIPAm-co-SBMA) possesses thermoresponsiveness and ionic strength responsiveness concurrently. At 293 K, both hydrophilic p(NIPAm) and superhydrophilic polysulfobetaine methacrylate (pSBMA) could appear on the outer surface of the nanogel; however, at 318 K, superhydrophilic pSBMA is on the outer surface to cover the hydrophobic p(NIPAm) core. As the temperature rises, the nanogel shrinks and remains antifouling all through. The salt-responsive property can be reflected by the nanogel size; the volumes of the nanogels in saline systems are larger than those in salt-free systems as the ionic condition inhibits the shrinkage of the zwitterionic pSBMA. This work exhibits the temperature-responsive and salt-responsive behavior of zwitterion-modified-pNIPAm nanogels at the molecular level and provides guidance in antifouling nanogel design.

Alleviating Effect of a Magnetite (Fe3O4) Nanogel against Waterborne-Lead-Induced Physiological Disturbances, Histopathological Changes, and Lead Bioaccumulation in African Catfish

Heavy metal toxicity is an important issue owing to its harmful influence on fish. Hence, this study is a pioneer attempt to verify the in vitro and in vivo efficacy of a magnetite (Fe3O4) nanogel (MNG) in mitigating waterborne lead (Pb) toxicity in African catfish. Fish (n = 160) were assigned into four groups for 45 days. The first (control) and second (MNG) groups were exposed to 0 and 1.2 mg L-1 of MNG in water. The third (Pb) and fourth (MNG + Pb) groups were exposed to 0 and 1.2 mg L-1 of MNG in water and 69.30 mg L-1 of Pb. In vitro, the MNG caused a dramatic drop in the Pb level within 120 h. The Pb-exposed group showed the lowest survival (57.5%) among the groups, with substantial elevations in hepato-renal function and lipid peroxide (MDA). Moreover, Pb exposure caused a remarkable decline in the protein-immune parameters and hepatic antioxidants, along with higher Pb residual deposition in muscles and obvious histopathological changes in the liver and kidney. Interestingly, adding aqueous MNG to Pb-exposed fish relieved these alterations and increased survivability. Thus, MNG is a novel antitoxic agent against Pb toxicity to maintain the health of C. gariepinus.

Nanogels as novel drug nanocarriers for CNS drug delivery

Nanogels are highly recognized as adaptable drug delivery systems that significantly contribute to improving various therapies and diagnostic examinations for different human diseases. These three-dimensional, hydrophilic cross-linked polymers have the ability to absorb large amounts of water or biological fluids. Due to the growing demand for enhancing current therapies, nanogels have emerged as the next-generation drug delivery system. They effectively address the limitations of conventional drug therapy, such as poor stability, large particle size, and low drug loading efficiency. Nanogels find extensive use in the controlled delivery of therapeutic agents, reducing adverse drug effects and enabling lower therapeutic doses while maintaining enhanced efficacy and patient compliance. They are considered an innovative drug delivery system that highlights the shortcomings of traditional methods. This article covers several topics, including the involvement of nanogels in the nanomedicine sector, their advantages and limitations, ideal properties like biocompatibility, biodegradability, drug loading capacity, particle size, permeability, non-immunological response, and colloidal stability. Additionally, it provides information on nanogel classification, synthesis, drug release mechanisms, and various biological applications. The article also discusses barriers associated with brain targeting and the progress of nanogels as nanocarriers for delivering therapeutic agents to the central nervous system.

Cytocompatibility and Wound Healing Activity of Chitosan Thiocolchicoside Lauric Acid Nanogel in Human Gingival Fibroblast Cells

AIM

To investigate the cytocompatibility effect and wound healing activity of chitosan thiocolchicoside lauric acid (CTL) nanogel using human gingival fibroblast (hGF) cells.

MATERIALS AND METHODS

hGF cells were established from gingival tissue as per the standard cell isolation protocol. The cytocompatibility effect was assessed using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide) assay. A scratch wound healing assay was performed to assess the wound-healing potential of CTL nanogel. For the nuclear morphological changes analysis, acridine orange staining was used in gingival fibroblast cells. The stained nuclei were viewed under a fluorescent microscope. ANOVA with posthoc analysis was performed using GraphPad Prism 5 software (Dotmatics, Boston, Massachusetts). The significance level (p-value) was expressed as <0.05.  Results: CTL nanogel did not show any significant cytotoxicity at concentrations 10-80 µl/ml (p<0.05). CTL nanogel at a concentration of 40µl/ml has a cytocompatibility effect on hGF cells and increases cell viability. In vitro scratch wound healing assay resulted in faster wound healing and cell migration with CTL nanogel when compared to the control group.

CONCLUSION

CTL nanogel has a significant effect on cell proliferation at various concentrations, which suggests its use as a safe and effective drug delivery system.

Small extracellular vesicles: a novel drug delivery system for neurodegenerative disorders

Neurodegenerative diseases (NDs) have a slow onset and are usually detected late during disease. NDs are often difficult to cure due to the presence of the blood-brain barrier (BBB), which makes it difficult to find effective treatments and drugs, causing great stress and financial burden to families and society. Currently, small extracellular vesicles (sEVs) are the most promising drug delivery systems (DDSs) for targeted delivery of molecules to specific sites in the brain as a therapeutic vehicle due to their low toxicity, low immunogenicity, high stability, high delivery efficiency, high biocompatibility and trans-BBB functionality. Here, we review the therapeutic application of sEVs in several NDs, including Alzheimer's disease, Parkinson's disease, and Huntington's disease, discuss the current barriers associated with sEVs and brain-targeted DDS, and suggest future research directions.

Nanogels for bone tissue engineering - from synthesis to application

Nanogels are cross-linked hydrogel nanoparticles with a three-dimensional, tunable porous structure that merges the best features of hydrogels and nanoparticles, including the ability to retain their hydrated nature and to swell and shrink in response to environmental changes. Nanogels have attracted increasing attention for use in bone tissue engineering as scaffolds for growth factor transport and cell adhesion. Their three-dimensional structures allow the encapsulation of a wide range of hydrophobic and hydrophilic drugs, enhance their half-life, and impede their enzymatic breakdown in vivo. Nanogel-based scaffolds are a viable treatment modality for enhanced bone regeneration. They act as carriers for cells and active ingredients capable of controlled release, enhanced mechanical support, and osteogenesis for enhanced bone tissue regeneration. However, the development of such nanogel constructs might involve combinations of several biomaterials to fabricate active ingredients that can control release, enhance mechanical support, and facilitate osteogenesis for more effective bone tissue regeneration. Hence, this review aims to highlight the potential of nanogel-based scaffolds to address the needs of bone tissue engineering.

Nanofertilizers: Types, Delivery and Advantages in Agricultural Sustainability

In an alarming tale of agricultural excess, the relentless overuse of chemical fertilizers in modern farming methods have wreaked havoc on the once-fertile soil, mercilessly depleting its vital nutrients while inflicting irreparable harm on the delicate balance of the surrounding ecosystem. The excessive use of such fertilizers leaves residue on agricultural products, pollutes the environment, upsets agrarian ecosystems, and lowers soil quality. Furthermore, a significant proportion of the nutrient content, including nitrogen, phosphorus, and potassium, is lost from the soil (50–70%) before being utilized. Nanofertilizers, on the other hand, use nanoparticles to control the release of nutrients, making them more efficient and cost-effective than traditional fertilizers. Nanofertilizers comprise one or more plant nutrients within nanoparticles where at least 50% of the particles are smaller than 100 nanometers. Carbon nanotubes, graphene, and quantum dots are some examples of the types of nanomaterials used in the production of nanofertilizers. Nanofertilizers are a new generation of fertilizers that utilize advanced nanotechnology to provide an efficient and sustainable method of fertilizing crops. They are designed to deliver plant nutrients in a controlled manner, ensuring that the nutrients are gradually released over an extended period, thus providing a steady supply of essential elements to the plants. The controlled-release system is more efficient than traditional fertilizers, as it reduces the need for frequent application and the amount of fertilizer. These nanomaterials have a high surface area-to-volume ratio, making them ideal for holding and releasing nutrients. Naturally occurring nanoparticles are found in various sources, including volcanic ash, ocean, and biological matter such as viruses and dust. However, regarding large-scale production, relying solely on naturally occurring nanoparticles may not be sufficient or practical. In agriculture, nanotechnology has been primarily used to increase crop production while minimizing losses and activating plant defense mechanisms against pests, insects, and other environmental challenges. Furthermore, nanofertilizers can reduce runoff and nutrient leaching into the environment, improving environmental sustainability. They can also improve fertilizer use efficiency, leading to higher crop yields and reducing the overall cost of fertilizer application. Nanofertilizers are especially beneficial in areas where traditional fertilizers are inefficient or ineffective. Nanofertilizers can provide a more efficient and cost-effective way to fertilize crops while reducing the environmental impact of fertilizer application. They are the product of promising new technology that can help to meet the increasing demand for food and improve agricultural sustainability. Currently, nanofertilizers face limitations, including higher costs of production and potential environmental and safety concerns due to the use of nanomaterials, while further research is needed to fully understand their long-term effects on soil health, crop growth, and the environment.

Gelatin as a bioactive nanodelivery system for functional food applications

Gelatin has long been used as an encapsulant agent in the pharmaceutical and biomedical industries because of its low cost, wide availability, biocompatibility, and degradability. However, the exploitation of gelatin for nanodelivery application is not fully achieved in the functional food filed. In this review article, we highlight the latest work being performed for gelatin-based nanocarriers, including polyelectrolyte complexes, nanoemulsions, nanoliposomes, nanogels, and nanofibers. Specifically, we discuss the applications and challenges of these nanocarriers for stabilization and controlled release of bioactive compounds. To achieve better efficacy, gelatin is frequently used in combination with other biomaterials such as polysaccharides. The fabrication and synergistic effects of the newly developed gelatin composite nanocarriers are also present.

The significance of quercetin-loaded advanced nanoformulations for the management of diabetic wounds

Quercetin is a well-known plant flavanol that exhibits multiple biological activities, including antioxidant, anti-inflammatory and anticancer activities. The role of quercetin in wound healing has been widely explored by a range of researchers in different models. However, the physicochemical properties, such as solubility and permeability, of this compound are low, which ultimately limits its bioavailability on the target site. To overcome these limitations for successful therapy, scientists have developed a range of nanoformulations that provide effective therapeutic potential. In this review, the broad mechanism of quercetin for acute and chronic wounds is covered. A compilation of recent advances on the horizon of wound healing via quercetin is incorporated with several advanced nanoformulations.

Delivery of Doxorubicin by Ferric Ion-Modified Mesoporous Polydopamine Nanoparticles and Anticancer Activity against HCT-116 Cells In Vitro

In clinical cancer research, photothermal therapy is one of the most effective ways to increase sensitivity to chemotherapy. Here, we present a simple and effective method for developing a nanotherapeutic agent for chemotherapy combined with photothermal therapy. The nanotherapeutic agent mesoporous polydopamine-Fe(III)-doxorubicin-hyaluronic acid (MPDA-Fe(III)-DOX-HA) was composed of mesoporous polydopamine modified by ferric ions and loaded with the anticancer drug doxorubicin (DOX), as well as an outer layer coating of hyaluronic acid. The pore size of the mesoporous polydopamine was larger than that of the common polydopamine nanoparticles, and the particle size of MPDA-Fe(III)-DOX-HA nanoparticles was 179 ± 19 nm. With the presence of ferric ions, the heat generation effect of the MPDA-Fe(III)-DOX-HA nanoparticles in the near-infrared light at 808 nm was enhanced. In addition, the experimental findings revealed that the active targeting of hyaluronic acid to tumor cells mitigated the toxicity of DOX on normal cells. Furthermore, under 808 nm illumination, the MPDA-Fe(III)-DOX-HA nanoparticles demonstrated potent cytotoxicity to HCT-116 cells, indicating a good anti-tumor effect in vitro. Therefore, the system developed in this work merits further investigation as a potential nanotherapeutic platform for photothermal treatment of cancer.

Advances in Nanogels for Topical Drug Delivery in Ocular Diseases

Nanotechnology has accelerated the development of the pharmaceutical and medical technology fields, and nanogels for ocular applications have proven to be a promising therapeutic strategy. Traditional ocular preparations are restricted by the anatomical and physiological barriers of the eye, resulting in a short retention time and low drug bioavailability, which is a significant challenge for physicians, patients, and pharmacists. Nanogels, however, have the ability to encapsulate drugs within three-dimensional crosslinked polymeric networks and, through specific structural designs and distinct methods of preparation, achieve the controlled and sustained delivery of loaded drugs, increasing patient compliance and therapeutic efficiency. In addition, nanogels have higher drug-loading capacity and biocompatibility than other nanocarriers. In this review, the main focus is on the applications of nanogels for ocular diseases, whose preparations and stimuli-responsive behaviors are briefly described. The current comprehension of topical drug delivery will be improved by focusing on the advances of nanogels in typical ocular diseases, including glaucoma, cataracts, dry eye syndrome, and bacterial keratitis, as well as related drug-loaded contact lenses and natural active substances.

Microfluidic production of nanogels as alternative triple transfection reagents for the manufacture of adeno-associated virus vectors

Adeno-associated viral vectors (AAVs) have proved a mainstay in gene therapy, owing to their remarkable transduction efficiency and safety profile. Their production, however, remains challenging in terms of yield, the cost-effectiveness of manufacturing procedures and large-scale production. In this work, we present nanogels produced by microfluidics as a novel alternative to standard transfection reagents such as polyethylenimine-MAX (PEI-MAX) for the production of AAV vectors with comparable yields. Nanogels were formed at pDNA weight ratios of 1 : 1 : 2 and 1 : 1 : 3, of pAAV cis-plasmid, pDG9 capsid trans-plasmid and pHGTI helper plasmid respectively, where vector yields at a small scale showed no significant difference to those of PEI-MAX. Weight ratios of 1 : 1 : 2 showed overall higher titers than 1 : 1 : 3, where nanogels with nitrogen/phosphate ratios of 5 and 10 produced yields of ≈8.8 × 10⁸ vg mL^-1 and ≈8.1 × 10⁸ vg mL^-1 respectively compared to ≈1.1 × 10⁹ vg mL^-1 for PEI-MAX. In larger scale production, optimised nanogels produced AAV at a titer of ≈7.4 × 10¹¹ vg mL^-1, showing no statistical difference from that of PEI-MAX at ≈1.2 × 10¹² vg mL^-1, indicating that equivalent titers can be achieved with easy-to-implement microfluidic technology at comparably lower costs than traditional reagents.

Nanodrug delivery systems for metabolic chronic liver diseases: advances and perspectives

Nanomedicines are revolutionizing healthcare as recently demonstrated by the Pfizer/BioNTech and Moderna COVID-2019 vaccines, with billions of doses administered worldwide in a safe manner. Nonalcoholic fatty liver disease is the most common noncommunicable chronic liver disease, posing a major growing challenge to global public health. However, due to unmet diagnostic and therapeutic needs, there is great interest in the development of novel translational approaches. Nanoparticle-based approaches offer novel opportunities for efficient and specific drug delivery to liver cells, as a step toward precision medicines. In this review, the authors highlight recent advances in nanomedicines for the generation of novel diagnostic and therapeutic tools for nonalcoholic fatty liver disease and related liver diseases.

Inorganic hollow mesoporous spheres-based delivery for antimicrobial agents

Microorganisms coexist with human beings and have formed a complex relationship with us. However, the abnormal spread of pathogens can cause infectious diseases thus demands antibacterial agents. Currently available antimicrobials, such as silver ions, antimicrobial peptides and antibiotics, have diverse concerns in chemical stability, biocompatibility, or triggering drug resistance. The "encapsulate-and-deliver" strategy can protect antimicrobials against decomposing, so to avoid large dose release induced resistance and achieve the controlled release. Considering loading capacity, engineering feasibility, and economic viability, inorganic hollow mesoporous spheres (iHMSs) represent one kind of promising and suitable candidates for real-life antimicrobial applications. Here we reviewed the recent research progress of iHMSs-based antimicrobial delivery. We summarized the synthesis of iHMSs and the drug loading method of various antimicrobials, and discussed the future applications. To prevent and mitigate the spread of an infective disease, multilateral coordination at the national level is required. Moreover, developing effective and practicable antimicrobials is the key to enhancing our capability to eliminate pathogenic microbes. We believe that our conclusion will be beneficial for researches on the antimicrobial delivery in both lab and mass production phases.

Folic acid-modified biocompatible Pullulan/poly(acrylic acid) nanogels for targeted delivery to MCF-7 cancer cells

We prepared a novel nanogel consisting of poly(acrylic acid) (PAA) and pullulan (Pull) via a facile and green irradiation protocol. Synthesized nanogels were modified with bovine serum albumin (BSA) and folic acid (FA) and then loaded with doxorubicin (DOX) to obtain a delivery system with tumor-specific targeting ability and enhanced biocompatibility. In-vitro DOX release was investigated at different pH values, and it was found that DOX release was higher in acidic media, which is an advantage for the internalization of nanoparticles in acidic tumor environment. MTT assay and DAPI staining were performed to evaluate the effects of nanogels on L929 and MCF-7 cells. Based on the results of in vitro studies, DOX-loaded nanogels were found to be effective on cancer cells, while the neat ones were nondestructive in both lines. Overall, we envision that the biocompatible and tumor-specific nanogels could be a promising safe drug carrier system for cancer therapy.

Nanomedicine based strategies for oligonucleotide traversion across the blood-brain barrier

Neurological disorders are considered the most prominent cause of disability worldwide. The major hurdle in the management of neurological disorders is the existence of the blood-brain barrier (BBB), which hinders the entry of several therapeutic moieties. In recent years, oligonucleotides have gained tremendous attention for their target specificity, diminished dose and adverse effects, thereby halting disease progression. However, enzymatic degradation, rapid clearance, limited circulation and availability at the bio-active site, etc., limit its clinical translation. Nanomedicine has opened up a breadth of opportunities in the delivery of oligonucleotides across the BBB. This review addresses the pitfalls associated with oligonucleotide delivery in traversing the BBB via nanotherapeutics for the management of brain disorders. Regulatory perspectives pertaining to hastening the clinical translation of oligonucleotide-loaded nanocarriers for brain delivery have been highlighted.

CuAAC ensembled 1,2,3-triazole linked nanogels for targeted drug delivery: a review

Copper(i) catalyzed alkyne azide cycloaddition (CuAAC), the quintessential example of 'click chemistry', provides an adaptable and adequate platform for the synthesis of nanogels for sustained drug release at targeted sites because of their better biocompatibility. The coupling of drugs, carried out via various synthetic routes including CuAAC, into long-chain polymeric forms like nanogels has exhibited considerable assurance in therapeutic advancements and intracellular drug delivery due to the progression of water solubility, evacuation of precocious drug release, and improved upthrust of the pharmacokinetics of the nanogels, thereby rendering them as better and efficient drug carriers. The inefficiency of drug transmission to the target areas due to the resistance of complex biological barriers in vivo is a major hurdle that impedes the therapeutic translation of nanogels. This review compiles the data of nanogels synthesized specifically via CuAAC 'click' methodology, as scaffolds for targeted drug delivery and their assimilation into nanomedicine. In addition, it elaborates the ability of CuAAC to graft specific moieties and conjugating biomolecules like proteins and growth factors, onto orthogonally functionalized polymer chains with various chemical groups resulting in nanogels that are not only more appealing but also more effective at delivering drugs, thereby enhancing their site-specific target approach and initiating selective therapies.

Molecularly Imprinted Nanomaterials with Stimuli Responsiveness for Applications in Biomedicine

The review aims to summarize recent reports of stimuli-responsive nanomaterials based on molecularly imprinted polymers (MIPs) and discuss their applications in biomedicine. In the past few decades, MIPs have been proven to show widespread applications as new molecular recognition materials. The development of stimuli-responsive nanomaterials has successfully endowed MIPs with not only affinity properties comparable to those of natural antibodies but also the ability to respond to external stimuli (stimuli-responsive MIPs). In this review, we will discuss the synthesis of MIPs, the classification of stimuli-responsive MIP nanomaterials (MIP-NMs), their dynamic mechanisms, and their applications in biomedicine, including bioanalysis and diagnosis, biological imaging, drug delivery, disease intervention, and others. This review mainly focuses on studies of smart MIP-NMs with biomedical perspectives after 2015. We believe that this review will be helpful for the further exploration of stimuli-responsive MIP-NMs and contribute to expanding their practical applications especially in biomedicine in the near future.

Antimicrobial Peptides against Bacterial Pathogens: Innovative Delivery Nanosystems for Pharmaceutical Applications

The introduction of antibiotics has revolutionized the treatment and prevention of microbial infections. However, the global spread of pathogens resistant to available antibiotics is a major concern. Recently, the WHO has updated the priority list of multidrug-resistant (MDR) species for which the discovery of new therapeutics is urgently needed. In this scenario, antimicrobial peptides (AMPs) are a new potential alternative to conventional antibiotics, as they show a low risk of developing antimicrobial resistance, thus preventing MDR bacterial infections. However, there are limitations and challenges related to the clinical impact of AMPs, as well as great scientific efforts to find solutions aimed at improving their biological activity, in vivo stability, and bioavailability by reducing the eventual toxicity. To overcome some of these issues, different types of nanoparticles (NPs) have been developed for AMP delivery over the last decades. In this review, we provide an update on recent nanosystems applied to AMPs, with special attention on their potential pharmaceutical applications for the treatment of bacterial infections. Among lipid nanomaterials, solid lipid NPs and lipid nanocapsules have been employed to enhance AMP solubility and protect peptides from proteolytic degradation. In addition, polymeric NPs, particularly nanogels, are able to help in reducing AMP toxicity and also increasing AMP loading. To boost AMP activity instead, mesoporous silica or gold NPs can be selected due to their easy surface functionalization. They have been also used as nanocarriers for different AMP combinations, thus synergistically potentiating their action against pathogens.

Synthesis and Characterization of Innovative Microgels Based on Polyacrylic Acid and Microalgae Cell Wall and Their Potential as Antigen Delivery Vehicles

In this study, hybrid polyacrylic acid and Schizochytrium sp. microalgae (PAA/Schizo) microgels were synthesized by inverse emulsion assisted by ultrasound using the cell wall fraction as crosslinker. Physicochemical characterization of PAA/Schizo microgels revealed polymeric spherical particles (288 ± 39 nm) and were deemed stable and negatively charged. The produced microgels are not inherently toxic as cell viability was sustained above 80% when mice splenocytes were exposed to concentrations ranging 10-900 µg/mL. PAA/Schizo microgels were evaluated as antigen delivery nanovehicle by adsorbing bovine serum albumin (BSA); with a loading efficiency of 72% and loading capacity of 362 µg/mg. Overall, intranasally-immunized BALB/c mice showed null IgG or IgA responses against PAA/Schizo microgel-BSA, whereas soluble BSA induced significant humoral responses in systemic and mucosal compartments. Splenocytes proliferation assay upon BSA stimulus revealed positive CD4+ T cells-proliferation response in PAA/Schizo microgels-BSA group. Thus, PAA/Schizo microgels constitute functional antigen delivery vehicles of simple and ecofriendly synthesis. Moreover, the use of cell wall fraction as cross-linker agent provides an alternative use for the generation of high-value products using residual algae biomass from the oil industry. Our data suggests that the PAA/Schizo microgels are potential antigen delivery vehicles for immunotherapy development.