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

The Dual Modification of PNIPAM and β-Cyclodextrin Grafted on Hyaluronic Acid as Self-Assembled Nanogel for Curcumin Delivery

Curcumin is an extract of turmeric (Curcuma longa) which possesses anti-inflammatory, anti-cancer and wound-healing effects and has been used as an active compound in biomedical research for many years. However, its poor solubility presents challenges for its use in drug delivery systems. A modified nanogel delivery system, with PNIPAM and β-cyclodextrin grafted onto hyaluronic acid (PNCDHA), was utilized to enhance the solubility. The polymer was characterized by NMR, and the inclusion complex between curcumin and β-cyclodextrin was confirmed by FTIR. The potential of this PNCDHA polymer complex as a drug delivery vehicle was supported by a curcumin encapsulation efficiency of 93.14 ± 5.6% and the release of encapsulated curcumin at 37 °C. At a concentration of 0.5% w/v in water, PNCDHA nanogels were biocompatible with fibroblast cell line (L929) up to a curcumin concentration of 50 µM. There was a direct concentration between curcumin loading and cellular internalization. A more detailed study of the cellular internalization of PNCDHA nanogel should be considered in order to clarify cellular delivery mechanisms and to assess how its viability as a carrier may be optimized.

Biomedicine Innovations and Its Nanohydrogel Classifications

As one of the most cutting-edge and promising polymer crosslinked network nanoparticle systems. Polymer nano-sized hydrogels (nanogels) have been a hot topic in the biomedical field over the last few decades. Due to their unique characteristics, which include their relatively high drug encapsulation efficiency, ease of preparation, high tunability, low toxicity, high stability in serum and responsive behavior to a range of stimuli to facilitate drug release. Nanogels are thought to be the next generation of drug delivery systems that can completely change the way that drug delivery systems have an impact on patients' lives. Nanogels have demonstrated significant potential in a variety of fields, including chemotherapy, diagnosis, organ targeting, and delivery of bioactive molecules of different dimensions. However, the lack of substantial clinical data from nanogels becomes one of the major barriers to translating the nanogel concept into a practical therapeutic application for many disease conditions. In addition, nanogel safety profiles have been the major concern that hinders it advancement to the clinical trial phase. This review aims to emphasize the unique properties of nanogels as delivery systems for a variety of bioactive molecules over other nano-delivery systems. Also, this review attempts to give insight into the recent progress in nanogels as a carrier in the field of nanomedicine to overcome complex biological barriers. Relevant scientific data and clinical rationale for the development and the potential use of nanogel as a carrier for targeted therapeutic interventions are discussed. Finally, the concluding points of this review highlight the importance of understanding the long-term toxicity profile of nanogel within the biological system to fully understand their biocompatibility.

Recent Advances in the Biomedical Applications of Functionalized Nanogels

Nanomaterials have been extensively used in several applications in the past few decades related to biomedicine and healthcare. Among them, nanogels (NGs) have emerged as an important nanoplatform with the properties of both hydrogels and nanoparticles for the controlled/sustained delivery of chemo drugs, nucleic acids, or other bioactive molecules for therapeutic or diagnostic purposes. In the recent past, significant research efforts have been invested in synthesizing NGs through various synthetic methodologies such as free radical polymerization, reversible addition-fragmentation chain-transfer method (RAFT) and atom transfer radical polymerization (ATRP), as well as emulsion techniques. With further polymeric functionalizations using activated esters, thiol-ene/yne processes, imines/oximes formation, cycloadditions, nucleophilic addition reactions of isocyanates, ring-opening, and multicomponent reactions were used to obtain functionalized NGs for targeted delivery of drug and other compounds. NGs are particularly intriguing for use in the areas of diagnosis, analytics, and biomedicine due to their nanodimensionality, material characteristics, physiological stability, tunable multi-functionality, and biocompatibility. Numerous NGs with a wide range of functionalities and various external/internal stimuli-responsive modalities have been possible with novel synthetic reliable methodologies. Such continuous development of innovative, intelligent materials with novel characteristics is crucial for nanomedicine for next-generation biomedical applications. This paper reviews the synthesis and various functionalization strategies of NGs with a focus on the recent advances in different biomedical applications of these surface modified/functionalized single-/dual-/multi-responsive NGs, with various active targeting moieties, in the fields of cancer theranostics, immunotherapy, antimicrobial/antiviral, antigen presentation for the vaccine, sensing, wound healing, thrombolysis, tissue engineering, and regenerative medicine.

Polysaccharide-based hydrogels for drug delivery and wound management: a review

INTRODUCTION

Polysaccharide-based hydrogels (PBHs) offer several advantages over their synthetic counterparts. Their natural origin contributes to their nontoxicity, high biocompatibility, and in vivo biodegradability. Their properties can be tuned finely to obtain hydrogels with desired mechanical, structural, and chemical properties.

AREAS COVERED

Such versatile characteristics have potentiated the use of PBHs for the delivery of drugs, vaccines, protein and peptide therapeutics, genes, cells, probiotics, bacteriophages, and other therapeutic agents. Recent advances in hydrogel-based formulations such as nanogels, microgels, microneedles, hydrogel beads, nanocarrier-loaded hydrogels, and complexation hydrogels have enabled the precise delivery of a wide range of therapeutics. This review aims to give a holistic overview of hydrogels in the delivery of a variety of therapeutics through different routes.

EXPERT OPINION

PBHs have been used to enable the oral delivery of vaccines and other biologicals, thereby allowing self-administration of life-saving vaccines during public health emergencies. There is a lack of commercialized wound dressings for the treatment of chronic wounds. PBH-based wound dressings, especially those based on chitosan and loaded with actives and growth factors, have the potential to help in the long-term treatment of such wounds. Recent developments in the 3D printing of hydrogels can enable the quick and large-scale production of drug-loaded hydrogels.

Development and biological evaluation of pNIPAM-based nanogels as vaccine carriers

"Smart" nanogels are an attractive tool for the development of new strategies of immunization in veterinary medicine. Here, we reported the synthesis and physicochemical characterization of thermoresponsive nanogels based on poly(N-isopropylacrylamide) (pNIPAM) and theirin vitro, ex vivoand in vivo (mice model) performance. Smart nanogels of ca. 250 nm, with a transition temperature of 32 °C were obtained by precipitation polymerization. Assays to evaluatepNIPAM nanogels cytotoxicity were performed in different cell lines showing high biocompatibility (>70 %). The efficient internalization of the system was studied by confocal microscopy as well as flow cytometry. The ability to protect and deliver antigens was analyzed using the outer membrane lipoprotein A (OmlA), an important virulence factor ofActinobacillus pleuropneumoniae(App)cause of porcine pleuropneumonia. This lipoprotein was synthesized by recombinant technology and its technique was also described. The biodistribution ofpNIPAM nanogels administered intranasally was performedinvivo and ex vivo through Pearl Imaging System, which showed that nanogels were kept mostly in the lungs during the evaluated time. Besides, the efficacy of the proposal nanogel-based vaccine was studiedin vivoby measuring the antibody titers of BALB/c mice inoculated with OmlA encapsulated intopNIPAM nanogels compared to OmlA plus aluminum hydroxide adjuvant. The results proved the ability of nanogels to stimulate a humoral immune response. Therefore, we have demonstrated thatpNIPAM nanogels can be used as an efficient platform for vaccine nanocarriers.

The application of nanotechnology in treatment of Alzheimer's disease

The buildup of beta-amyloid plaques in the brain results in Alzheimer's disease (AD), a neurodegenerative condition. A permanent treatment for AD is not yet available. Only a slowing down of its advancement is possible with the current pharmaceutical options. Nevertheless, nanotechnology has proven to be advantageous in medical applications. It has a lot of potential for AD therapy, particularly in diagnosing the condition and providing an alternative course of treatment. In this review, we outline the developments and benefits of nanomedicines in treating AD. Prospective nanomedicines for diagnosing and surveillance therapeutic interventions for AD and other diseases of the central nervous system (CNS) may be clinically accessible, persuading the development of investigation in this field.

Progressive Application of Marine Biomaterials in Targeted Cancer Nanotherapeutics

The marine microenvironment harbors many unique species of organisms that produce a plethora of compounds that help mankind cure a wide range of diseases. The diversity of products from the ocean bed serves as potentially healing materials and inert vehicles carrying the drug of interest to the target site. Several composites still lay undiscovered under the blue canopy, which can provide treatment for untreated diseases that keep haunting the earth periodically. Cancer is one such disease that has been of interest to several eminent scientists worldwide due to the heterogenic complexity involved in the disease's pathophysiology. Due to extensive globalization and environmental changes, cancer has become a lifestyle disease continuously increasing exponentially in the current decade. This ailment requires a definite remedy that treats by causing minimal damage to the body's normal cells. The application of nanotechnology in medicine has opened up new avenues of research in targeted therapeutics due to their highly malleable characteristics. Marine waters contain an immense ionic environment that succors the production of distinct nanomaterials with exceptional character, yielding highly flexible molecules to modify, thus facilitating the engineering of targeted biomolecules. This review provides a short insight into an array of marine biomolecules that can be probed into cancer nanotherapeutics sparing healthy cells.

Assessing the In Vivo Biocompatibility of Molecularly Imprinted Polymer Nanoparticles

Molecularly imprinted polymer nanoparticles (nanoMIPs) are high affinity synthetic receptors which show promise as imaging and therapeutic agents. Comprehensive analysis of the in vivo behaviour of nanoMIPs must be performed before they can be considered for clinical applications. This work reports the solid-phase synthesis of nanoMIPs and an investigation of their biodistribution, clearance and cytotoxicity in a rat model following both intravenous and oral administration. These nanoMIPs were found in each harvested tissue type, including brain tissue, implying their ability to cross the blood-brain barrier. The nanoMIPs were cleared from the body via both faeces and urine. Furthermore, we describe an immunogenicity study in mice, demonstrating that nanoMIPs specific for a cell surface protein showed moderate adjuvant properties, whilst those imprinted for a scrambled peptide showed no such behaviour. Given their ability to access all tissue types and their relatively low cytotoxicity, these results pave the way for in vivo applications of nanoMIPs.

The Anti-Psoriatic Efficacy and Safety Profile of Topical and Intralesional Methotrexate: A Literature Review

Methotrexate (MTX) has long been considered the first-line oral systemic pharmacotherapy for psoriasis. The drug has several well-known systemic side effects, such as bone marrow suppression and hepatotoxicity. To avoid them, the use of topical or intralesional administrations of MTX has become an interesting option. With the advent of novel drug delivery systems, especially nanocarriers, the usage of a high-efficacy and safe topical MTX for psoriasis has nearly been attained. This review examined the development, anti-psoriatic efficacy and adverse effects of topical forms of MTX (plain MTX; MTX with chemical enhancer; MTX using nanotechnology; MTX with protein transduction domains; MTX with liquid crystalline systems; and MTX with physical enhancer/laser) and intralesional MTX in psoriasis patients and psoriasis-induced animals. The efficacy of topical MTX varied with the drug delivery technology employed. Nevertheless, the overall safety profile of the topical forms was favourable. A 25 mg/mL MTX solution injected intralesionally at the nail matrix worked well for nail psoriasis recalcitrant to topical treatment. To improve the standard of care for patients with psoriasis, randomized controlled trials that establish the most effective MTX-delivery system are needed.

Physically stimulus-responsive nanoparticles for therapy and diagnosis

Nanoparticles offer numerous advantages in various fields of science, particularly in medicine. Over recent years, the use of nanoparticles in disease diagnosis and treatments has increased dramatically by the development of stimuli-responsive nano-systems, which can respond to internal or external stimuli. In the last 10 years, many preclinical studies were performed on physically triggered nano-systems to develop and optimize stable, precise, and selective therapeutic or diagnostic agents. In this regard, the systems must meet the requirements of efficacy, toxicity, pharmacokinetics, and safety before clinical investigation. Several undesired aspects need to be addressed to successfully translate these physical stimuli-responsive nano-systems, as biomaterials, into clinical practice. These have to be commonly taken into account when developing physically triggered systems; thus, also applicable for nano-systems based on nanomaterials. This review focuses on physically triggered nano-systems (PTNSs), with diagnostic or therapeutic and theranostic applications. Several types of physically triggered nano-systems based on polymeric micelles and hydrogels, mesoporous silica, and magnets are reviewed and discussed in various aspects.

pH and Reduction Dual-Responsive Nanogels as Smart Nanocarriers to Resist Doxorubicin Aggregation

The use of smart nanocarriers that can modulate therapeutic release aided by biological cues can prevent undesirable cytotoxicity caused by the premature release of cytotoxic drugs during nanocarrier circulation. In this report, degradable nanocarriers based on pH/reduction dual-responsive nanogels were synthesized to encapsulate doxorubicin hydrochloride (DOX) and specifically boost the release of DOX in conditions characteristic of the cancer microenvironment. Nanogels containing anionic monomer 2-carboxyethyl acrylate (CEA) and N,N′-bis(acryloyl)cystamine (CBA) as a degradable crosslinker have been successfully synthesized via photoinitiated free radical polymerization. The loading process was conducted after polymerization by taking advantage of the electrostatic interaction between the negatively charged nanogels and the positively charged DOX. In this case, a high drug loading capacity (DLC) of up to 27.89% was achieved. The entrapment of DOX into a nanogel network could prevent DOX from aggregating in biological media at DOX concentrations up to ~160 µg/mL. Anionic nanogels had an average hydrodynamic diameter (d_H) of around 90 nm with a negative zeta (ζ) potential of around −25 mV, making them suitable for targeting cancer tissue via the enhanced permeation effect. DOX-loaded nanogels formed a stable dispersion in different biological media, including serum-enriched cell media. In the presence of glutathione (GSH) and reduced pH, drug release was enhanced, which proves dual responsivity. An in vitro study using the HCT 116 colon cancer cell line demonstrated the enhanced cytotoxic effect of the NG-CBA/DOX-1 nanogel compared to free DOX. Taken together, pH/reduction dual-responsive nanogels show promise as drug delivery systems for anticancer therapy.

Polyvinylpyrrolidone K-30-Based Crosslinked Fast Swelling Nanogels: An Impeccable Approach for Drug's Solubility Improvement

Poor solubility is a global issue of copious pharmaceutical industries as large number of drugs in development stage as well as already marketed products are poorly soluble which results in low dissolution and ultimately dosage increase. Current study is aimed at developing a polyvinylpyrrolidone- (PVP-K30-) based nanogel delivery system for solubility enhancement of poorly soluble drug olanzapine (OLP), as solubilization enhancement is the most noteworthy application of nanosystems. Crosslinking polymerization with subsequent condensation technique was used for the synthesis of nanogels, a highly responsive polymeric networks in drug's solubility. Developed nanogels were characterized by percent entrapment efficiency, sol-gel, percent swelling, percent drug loaded content (%DLC), percent porosity, stability, solubility, in vitro dissolution studies, FTIR, XRD, and SEM analysis. Furthermore, cytotoxicity study was conducted on rabbits to check the biocompatibility of the system. Particle size of nanogels was found with 178.99 ± 15.32 nm, and in vitro dissolution study exhibited that drug release properties were considerably enhanced as compared to the marketed formulation OLANZIA. The solubility studies indicated that solubility of OLP was noticeably improved up to 36.7-fold in phosphate buffer of pH 6.8. In vivo cytotoxicity study indicated that prepared PVP-K30-based formulation was biocompatible. On the basis of results obtained, the developed PVP-K30-co-poly (AMPS) nanogel delivery system is expected to be safe, effective, and cost-effective for solubility improvement of poorly soluble drugs.

Nanogel-mediated delivery of oncomodulin secreted from regeneration-associated macrophages promotes sensory axon regeneration in the spinal cord

Preconditioning nerve injury enhances axonal regeneration of dorsal root ganglia (DRG) neurons in part by driving pro-regenerative perineuronal macrophage activation. How these macrophages influence the neuronal capacity of axon regeneration remains elusive. We report that oncomodulin (ONCM) is produced from the regeneration-associated macrophages and strongly influences regeneration of DRG sensory axons. We also attempted to promote sensory axon regeneration by nanogel-mediated delivery of ONCM to DRGs.

Methods:In vitro neuron-macrophage interaction model and preconditioning sciatic nerve injury were used to verify the necessity of ONCM in preconditioning injury-induced neurite outgrowth. We developed a nanogel-mediated delivery system in which electrostatic encapsulation of ONCM by a reducible epsilon-poly(_L-lysine)-nanogel (REPL-NG) enabled a controlled release of ONCM.

Results: Sciatic nerve injury upregulated ONCM in DRG macrophages. ONCM in macrophages was necessary to produce pro-regenerative macrophages in the in vitro model of neuron-macrophage interaction and played an essential role in preconditioning-induced neurite outgrowth. ONCM increased neurite outgrowth in cultured DRG neurons by activating a distinct gene set, particularly neuropeptide-related genes. Increasing extracellularly secreted ONCM in DRGs sufficiently enhanced the capacity of neurite outgrowth. Intraganglionic injection of REPL-NG/ONCM complex allowed sustained ONCM activity in DRG tissue and achieved a remarkable long-range regeneration of dorsal column sensory axons beyond spinal cord lesion.

Conclusion: NG-mediated ONCM delivery could be exploited as a therapeutic strategy for promoting sensory axon regeneration following spinal cord injury.

Polysaccharide-based nano-delivery systems for encapsulation, delivery, and pH-responsive release of bioactive ingredients

Polysaccharides are natural polymers isolated from plants, microorganisms, algae, and some animals they are composed of aldoses or ketoses linked by glycosidic bonds. Due to the affordability, abundance, safety, and functionality, polysaccharides are widely used in the foods and medicines to construct oral delivery systems for sensitive bioactive ingredients. In this article, the characteristics and applications of nanoscale polysaccharide-based delivery carriers are reviewed, including their ability to encapsulate, protect, and deliver bioactive ingredients. This review discusses the sources, characteristics, and functional properties of common food polysaccharides, including starch, pectin, chitosan, xanthan gum, and alginate. It also highlights the potential advantages of using polysaccharides for the construction of nano-delivery systems, such as nanoparticles, nanogels, nanoemulsions, nanocapsules, and nanofibers. Moreover, the application of delivery systems assembled from polysaccharides is summarized, with a focus on pH-responsive delivery of bioactives. There are some key findings and conclusions: Nanoscale polysaccharide delivery systems provide several advantages, including improved water-dispersibility, flavor masking, stability enhancement, reduced volatility, and controlled release; Polysaccharide nanocarriers can be used to construct pH-responsive delivery vehicles to achieve intestinal-targeted delivery and controlled release of bioactive ingredients; Polysaccharides can be used in combination with other biopolymers to form composite delivery systems with enhanced functional attributes.

Nanogels as Novel Nanocarrier Systems for Efficient Delivery of CNS Therapeutics

Nanogels have come out as a great potential drug delivery platform due to its prominently high colloidal stability, high drug loading, core-shell structure, good permeation property and can be responsive to environmental stimuli. Such nanoscopic drug carriers have more excellent abilities over conventional nanomaterials for permeating to brain parenchyma in vitro and in vivo. Nanogel-based system can be nanoengineered to bypass physiological barriers via non-invasive treatment, rendering it a most suitable platform for the management of neurological conditions such as neurodegenerative disorders, brain tumors, epilepsy and ischemic stroke, etc. Therapeutics of central nervous system (CNS) diseases have shown marked limited site-specific delivery of CNS by the poor access of various drugs into the brain, due to the presences of the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB). Hence, the availability of therapeutics delivery strategies is considered as one of the most major challenges facing the treatment of CNS diseases. The primary objective of this review is to elaborate the newer advances of nanogel for CNS drugs delivery, discuss the early preclinical success in the field of nanogel technology and highlight different insights on its potential neurotoxicity.

Trehalose-releasing nanogels: A step toward a trehalose delivery vehicle for autophagy stimulation

Trehalose has been widely studied as a treatment for a variety of human disorders due to its ability to stimulate autophagy. Trehalose, however, is poorly adsorbed and is hydrolyzed in the intestinal mucosa, and oral delivery requires relatively high doses to induce autophagy. The parenteral injection of trehalose-releasing nanogels proposed in this study offers an alternative mode of delivery. This study aimed to develop stable colloidal dispersions of trehalose-rich nanogels that could sustainably release trehalose under physiologically relevant conditions. The nanogel design was based on the covalent incorporation of 6-O-acryloyl-trehalose within a polymer network. A series of nine trehalose-rich nanogels with highly conjugated trehalose (up to 59 % w/w) were synthesized and shown to sustainably release trehalose at a rate that is not dose dependent. The nanogels were optimized to keep colloidal stability in serum-enriched cell culture media. The stable nanogels were not cytotoxic to primary HUVECs. Two selected nanogels with opposite surface charges were subjected to extended in vitro characterization that included a cellular uptake study and a hemocompatibility assay. Both nanogels were efficiently taken up by HUVECs during a short incubation. They also proved not to be hemolytic to human RBCs in concentrations up to 2.0 mg/mL. Finally, an in vivo autophagy stimulation study employing transgenic zebrafish and Drosophila larvae demonstrated that prolonged exposure to a cationic trehalose-releasing nanogel can induce autophagic activity in in vivo systems without any detectable toxicity.

Recent Developments on Ionic Liquids and Deep Eutectic Solvents for Drug Delivery Applications

The field of Ionic liquids (ILs) and deep eutectic solvents (DESs) is continuously expanding due to their exceptional unique properties and highly tunable nature, which finds applications in broad areas of modern science. Considering numerous possible IL and DES combinations prepared with active pharmaceutical ingredients (APIs), they find applications in pharmaceutical sciences. They can also serve as potential components of drug formulations and hence they have drawn the attention of formulation scientists. Herein, the concept of pharmaceutical ILs and DESs are discussed briefly. The possible applications of these solvent systems for slow drug delivery including nanoscale drug delivery are discussed citing various examples from the published literature. Although the ILs and DESs are found to be suitable for various drug delivery applications but still none of the slow drug delivery vehicles based on these solvents is in practical use. The data relating to long-term toxicity upon administration in the human body followed by various safety evaluations, clinical trials, etc. are pending for such new drug delivery systems. However, proof of concept studies done on the retention of biological activities in the ionic form is quite encouraging and such studies indicate the possibility of application of such new systems in the development of biomedical research and related industries in near future.

Synthesis and characterization of dual-responsive poly(N-vinylcaprolactam-co-N-methylolacrylamide) nanogels

This article reports the synthesis of poly(N-vinylcaprolactam-co-N-methylolacrylamide) (P(NVCL-co-NMA)) nanogels and investigates their thermo-/pH-responsive behavior. The formation of nanogels was synthesized using free radical emulsion polymerization by varying the monomer composition of NVCL:NMA, and their molecular structure was characterized by ¹H-NMR and FTIR. It was found that the nanogels were successfully prepared, and the nanogels exhibited LCST-type phase transition behavior. Cloud point transition temperature (T_c) was studied as a function of copolymer composition, MBA concentration, and pH of the solution by exploring their changes in turbidity using UV-vis spectrophotometer. Our studies reveal that T_c nanogels increased with increasing concentration of NMA, which is due to the hydrophilicity of NMA. Our research also demonstrated that the increase in MBA percentage could decrease the T_c of the synthesized nanogels. Interestingly, P(NVCL-co-NMA) nanogels showed not only a thermoresponsive behavior but also a pH response with increasing T_c in a strong acidic environment owing to the H-bonds within the polymer chains. The results show that nanogels with initial monomer composition of NVCL and NMA of 75% and 25%, respectively, and using 4% of MBA showed T_c around 35°C at pH 7.4. In addition, DLS studies also confirmed this result since the particle sizes became much larger after surpassing the temperature of 35°C. Due to this founding, such nanogels might have potential application in controlled release. Nevertheless, further studies regarding the adjustment of T_c are still needed.

The Influence of Short Motifs on the Anticancer Activity of HB43 Peptide

Despite the remarkable similarity in amino acid composition, many anticancer peptides (ACPs) display significant differences in terms of activity. This strongly suggests that particular relative dispositions of amino acids (motifs) play a role in the interaction with their biological target, which is often the cell membrane. To better verify this hypothesis, we intentionally modify HB43, an ACP active against a wide variety of cancers. Sequence alignment of related ACPs by ADAPTABLE web server highlighted the conserved motifs that could be at the origin of the activity. In this study, we show that changing the order of amino acids in such motifs results in a significant loss of activity against colon and breast cancer cell lines. On the contrary, amino acid substitution in key motifs may reinforce or weaken the activity, even when the alteration does not perturb the amphipathicity of the helix formed by HB43 on liposomes mimicking their surface. NMR and MD simulations with different membrane models (micelles, bicelles, and vesicles) indicate that the activity reflects the insertion capability in cancer-mimicking serine-exposing membranes, supported by the insertion of N-terminal phenylalanine in the FAK motif and the anchoring to the carboxylate of phosphatidylserine by means of arginine side chains.

Nanomaterials Based on Functional Polymers for Sensitizing Cancer Radiotherapy

Despite being the mainstay treatment for many types of cancer in clinic, radiotherapy is undertaking great challenges in overcoming a series of limitations. Radiosensitizers are promising agents capable of depositing irradiation energy and generating free radicals to enhance the radiosensitivity of tumor cells. Combining radiosensitizers with functional polymer-based nanomaterials holds great potential to improve biodistribution, circulation time, and stability in vivo. The derived polymeric nano-radiosensitizers can significantly improve the efficiency of tumor targeting and radiotherapy, and reduce the side effect to healthy tissues. In this review, we provide an overview of functional polymer-based nanomaterials for radiosensitization in recent years. Particular emphases are given to the action mechanisms, drug loading methods, targeting efficiencies, the impact on therapeutic effects and biocompatibility of various radiosensitizing polymers, which are classified as polymeric micelles, dendrimers, polymeric nanospheres, nanoscale coordination polymers, polymersomes, and nanogels. The challenges and outlooks of polymeric nano-radiosensitizers are also discussed. This article is protected by copyright. All rights reserved.

A hyaluronic acid-based nanogel for the co-delivery of nitric oxide (NO) and a novel antimicrobial peptide (AMP) against bacterial biofilms

Biofilms are a global health concern because they are associated with chronic and recurrent infections as well as resistance to conventional antibiotics. The aim of this study was to prepare a nanogel for the co-delivery of NO and AMPs against bacteria and biofilms. The NO-releasing nanogel was prepared by crosslinking HA solution with divinyl sulfone and extensively characterized. The nanogel was found to be biocompatible, injectable and NO release from the gel was sustained over a period of 24 h. In vitro antibacterial studies showed that the NO-AMP-loaded nanogel exhibited a broad spectrum antibacterial/antibiofilm activity. The NO-releasing nanogel had a greater antibacterial effect when compared to NO alone with MIC values of 1.56, 0.78 and 0.39 μg/ml against Escherichia coli, Methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa bacteria respectively. The antibiofilm results showed there was a 12.5 and 24-folds reduction in biofilms of MRSA, and P. aeruginosa respectively for catheters exposed to nanogel loaded with AMP/NO when compared to only NO, while a 7 and 9.4-folds reduction in biofilms of MRSA, and P. aeruginosa respectively was displayed by the nanogel loaded with only NO compared to only NO. The AMP/NO-releasing nanogel showed the potential to combat both biofilms and bacterial infections.

Crossing the Blood-Brain Barrier: Advances in Nanoparticle Technology for Drug Delivery in Neuro-Oncology

The blood-brain barrier (BBB) constitutes a microvascular network responsible for excluding most drugs from the brain. Treatment of brain tumors is limited by the impermeability of the BBB and, consequently, survival outcomes for malignant brain tumors remain poor. Nanoparticles (NPs) represent a potential solution to improve drug transport to brain tumors, given their small size and capacity to target tumor cells. Here, we review the unique physical and chemical properties of NPs that aid in BBB transport and discuss mechanisms of NP transport across the BBB, including paracellular transport, carrier-mediated transport, and adsorptive- and receptor-mediated transcytosis. The major types of NPs investigated for treatment of brain tumors are detailed, including polymeric NPs, liposomes, solid lipid NPs, dendrimers, metals, quantum dots, and nanogels. In addition to their role in drug delivery, NPs can be used as imaging contrast agents and can be conjugated with imaging probes to assist in visualizing tumors, demarcating lesion boundaries and margins, and monitoring drug delivery and treatment response. Multifunctional NPs can be designed that are capable of targeting tumors for both imaging and therapeutic purposes. Finally, limitations of NPs for brain tumor treatment are discussed.

Complexation of DNA with Thermoresponsive Charged Microgels: Role of Swelling State and Electrostatics

Micro- and nanogels are being increasingly used to encapsulate bioactive compounds. Their soft structure allows large loading capacity while their stimuli responsiveness makes them extremely versatile. In this work, the complexation of DNA with thermoresponsive microgels is presented. To this end, PEGylated charged microgels based on poly-N-isopropylacrylamide have been synthesized, allowing one to explore the electrostatics of the complexation. Cationic microgels complexate spontaneously by electrostatic attraction to oppositely charged DNA as demonstrated by electrophoretic mobility of the complexes. Then, Langmuir monolayers reveal an increased interaction of DNA with swollen microgels (20 °C). Anionic microgels require the presence of multivalent cations (Ca²⁺) to promote the complexation, overcoming the electrostatic repulsion with negatively charged DNA. Then again, Langmuir monolayers evidence their complexation at the surface. However, the presence of Ca²⁺ seems to induce profound changes in the interaction and surface conformation of anionic microgels. These alterations are further explored by measuring adsorbed films with the pendant drop technique. Conformational changes induced by Ca²⁺ on the structure of the microgel can ultimately affect the complexation with DNA and should be considered in the design. The combination of microstructural and surface properties for microgels offers a new perspective into complexation of DNA with soft particles with biomedical applications.

The nanotechnological approach for nasal delivery of peptide drugs: a comprehensive review

This review gathers recent studies, patents, and clinical trials involving the nasal administration of peptide drugs to supply a panorama of developing nanomedicine advances in this field. Peptide drugs have been featured in the pharmaceutical market, due to their high efficacy, biological activity, and low immunogenicity. Pharmaceutical industries need technology to circumvent issues relating to peptide stability and bioavailability. The oral route offers very harsh and unfavourable conditions for peptide administration, while the parenteral route is inconvenient and risky for patients. Nasal administration is an attractive alternative, mainly when associated with nanotechnological approaches. Nanomedicines may improve the nasal administration of peptide drugs by providing protection for the macromolecules from enzymes while also increasing their time of retention and permeability in the nasal mucosa. Nanomedicines for nasal administration containing peptide drugs have been acclaimed for both prevention, and treatment, of infections, including the pandemic COVID-19, cancers, metabolic and neurodegenerative diseases.

Translating Therapeutic Microgels into Clinical Applications

Microgels are crosslinked, water-swollen networks with a 10 nm to 100 µm diameter and can be modified chemically or biologically to render them biocompatible for advanced clinical applications. Depending on their intended use, microgels require different mechanical and structural properties, which can be engineered on demand by altering the biochemical composition, crosslink density of the polymer network, and the fabrication method. Here, the fundamental aspects of microgel research and development, as well as their specific applications for theranostics and therapy in the clinic, are discussed. A detailed overview of microgel fabrication techniques with regards to their intended clinical application is presented, while focusing on how microgels can be employed as local drug delivery materials, scavengers, and contrast agents. Moreover, microgels can act as scaffolds for tissue engineering and regeneration application. Finally, an overview of microgels is given, which already made it into pre-clinical and clinical trials, while future challenges and chances are discussed. This review presents an instructive guideline for chemists, material scientists, and researchers in the biomedical field to introduce them to the fundamental physicochemical properties of microgels and guide them from fabrication methods via characterization techniques and functionalization of microgels toward specific applications in the clinic.

Modern Herbal Nanogels: Formulation, Delivery Methods, and Applications

This study examined the most recent advancements in nanogel production and drug delivery. Phytochemistry is a discipline of chemistry that studies herbal compounds. Herbal substances have aided in the development of innovative remedies for a wide range of illnesses. Several of these compounds are forbidden from being used in medications due to broad medical characteristics and pharmacokinetics. A variety of new technical approaches have been investigated to ameliorate herbal discoveries in the pharmaceutical sector. The article focuses on the historical data for herb-related nanogels that are used to treat a variety of disorders with great patient compliance, delivery rate, and efficacy. Stimulus-responsive nanogels such as temperature responsive and pH-responsive systems are also discussed. Nanogel formulations, which have been hailed as promising targets for drug delivery systems, have the ability to alter the profile of a drug, genotype, protein, peptide, oligosaccharide, or immunogenic substance, as well as its ability to cross biological barriers, biodistribution, and pharmacokinetics, improving efficacy, safety, and patient cooperation.

Transdermal Delivery of Therapeutic Compounds With Nanotechnological Approaches in Psoriasis

Psoriasis is a chronic, immune-mediated skin disorder involving hyperproliferation of the keratinocytes in the epidermis. As complex as its pathophysiology, the optimal treatment for psoriasis remains unsatisfactorily addressed. Though systemic administration of biological agents has made an impressive stride in moderate-to-severe psoriasis, a considerable portion of psoriatic conditions were left unresolved, mainly due to adverse effects from systemic drug administration or insufficient drug delivery across a highly packed stratum corneum via topical therapies. Along with the advances in nanotechnologies, the incorporation of nanomaterials as topical drug carriers opens an obvious prospect for the development of antipsoriatic topicals. Hence, this review aims to distinguish the benefits and weaknesses of individual nanostructures when applied as topical antipsoriatics in preclinical psoriatic models. In view of specific features of each nanostructure, we propose that a proper combination of distinctive nanomaterials according to the physicochemical properties of loaded drugs and clinical features of psoriatic patients is becoming a promising option that potentially drives the translation of nanomaterials from bench to bedside with improved transdermal drug delivery and consequently therapeutic effects.

Attacking the Intruder at the Gate: Prospects of Mucosal Anti SARS-CoV-2 Vaccines

The sudden outbreak of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic in December 2019 caused crises and health emergencies worldwide. The rapid spread of the virus created an urgent need for the development of an effective vaccine and mass immunization to achieve herd immunity. Efforts of scientific teams at universities and pharmaceutical companies around the world allowed for the development of various types of preparations and made it possible to start the vaccination process. However, it appears that the developed vaccines are not effective enough and do not guarantee long-lasting immunity, especially for new variants of SARS-CoV-2. Considering this problem, it is promising to focus on developing a Coronavirus Disease 2019 (COVID-19) mucosal vaccine. Such a preparation applied directly to the mucous membranes of the upper respiratory tract might provide an immune barrier at the primary point of virus entry into the human body while inducing systemic immunity. A number of such preparations against SARS-CoV-2 are already in various phases of preclinical and clinical trials, and several of them are very close to being accepted for general use, constituting a milestone toward pandemic containment.

Co-delivery of paclitaxel and doxorubicin using polypeptide-engineered nanogels for combination therapy of tumor

Loading of chemotherapeutic agents into nanoparticles has been demonstrated to be an effective strategy for cancer therapy. However, simultaneous delivery of different functional drugs to tumor sites for chemotherapy still remains challenging. In this study, nanogels formed by an engineered coiled-coil polypeptide PC₁₀A were designed and prepared as a carrier for co-delivery of paclitaxel (PTX) and doxorubicin (DOX) through ultrasonic treatment and electrostatic adsorption. The drug loading content and encapsulation efficiency of PTX and DOX in the PC₁₀A/PTX/DOX nanogels were 5.98 wt%, 70 wt%, and 8.55 wt%, 83 wt%, respectively. Because the polypeptide PC₁₀A was non-toxic and biodegradable, the PC₁₀A/PTX/DOX nanogels exhibited good biocompatibility. Thein vitroandin vivoantitumor experiments showed that the PC₁₀A/PTX/DOX nanogels possessed obviously synergistic therapy effect of tumors and lower side effects compared with free PTX/DOX. Therefore, the PC₁₀A/PTX/DOX nanogels are promising to provide a new strategy for combination therapy of different functional drugs.

The Unique Carboxymethyl Fenugreek Gum Gel Loaded Itraconazole Self-Emulsifying Nanovesicles for Topical Onychomycosis Treatment

The novel itraconazole (ITZ) nail penetration enhancing self-emulsifying nanovesicles (ITZ-nPEVs) loaded in carboxymethyl fenugreek gum (CMFG) gel circumvent the systemic onychomycosis treatment. The ITZ-nPEVs were prepared by the thin film hydration technique, and the particle size (PS), zeta potential (ZP), drug content (DC), entrapment efficiency (% EE), deformity index (DI), viscosity, morphology, and physical stability of the ITZ-nPEVs were measured. In terms of nail hydration, transungual drug absorption, and antifungal efficacy against Candida albicans, the chosen ITZ-nPEVs, nPEV-loaded CMFG (CMFG-ITZ-nPEVs) gel, and the commercialized Itrostred gel were compared. The ITZ-nPEVs showed spherical structure with high DC, % EE, low PS and PDI and positive ZP of ITZ ranging from 95.36 to 93.89 mg/5 mL and 95.36–96.94%, 196.55–252.5 nm, 0.092–0.49, and +11.1 to +22.5 mV, respectively. Compared to the Itrostred gel, the novel ITZ-nPEVs exhibited hydration enhancement factor for 24 h (HE24) of 1.53 and 1.39 drug uptake enhancement factor into nail clippings. Moreover, zone of inhibitions for ITZ-nPEVs (27.0 ± 0.25 mm) and CMFG-ITZ-nPEVs (33.2 ± 0.09 mm) against Candida albicans were significantly greater than that of Itrostred gel (22.9 ± 0.44 mm). For clinical investigation on onychomycotic patients, a nail penetration enhancer containing ITZ-nPEV-loaded CMFG gel presents a highly promising approach.

Overview of nanoparticulate strategies for solubility enhancement of poorly soluble drugs

Poor aqueous solubility and poor bioavailability are major issues with many pharmaceutical industries. By some estimation, 70-90% drug candidates in development stage while up-to 40% of the marketed products are poorly soluble which leads to low bioavailability, reduced therapeutic effects and dosage escalation. That's why solubility is an important factor to consider during design and manufacturing of the pharmaceutical products. To-date, various strategies have been explored to tackle the issue of poor solubility. This review article focuses the updated overview of commonly used macro and nano drug delivery systems and techniques such as micronization, solid dispersion (SD), supercritical fluid (SCF), hydrotropy, co-solvency, micellar solubilization, cryogenic technique, inclusion complex formation-based techniques, nanosuspension, solid lipid nanoparticles, and nanogels/nanomatrices explored for solubility enhancement of poorly soluble drugs. Among various techniques, nanomatrices were found a promising and impeccable strategy for solubility enhancement of poorly soluble drugs. This article also describes the mechanism of action of each technique used in solubilization enhancement.

Dual-responsive nisin loaded chondroitin sulfate nanogel for treatment of bacterial infection in soft tissues

Chondroitin sulfate-Nisin nanogels (CS-N NGs) were prepared by electrostatic interaction for nisin delivery as an antibacterial agent in the treatment of bacterial infections caused by some clinical strains of methicillin-resistant and methicillin-sensitive Staphylococcus aureus (S. aureus). The physical properties of CS-N NGs were evaluated using Fourier-transform infrared spectroscopy, dynamic light scattering, and field emission scanning electron microscopy. The average diameter of obtained CS-N NGs was about 65 nm and the stability of nanogels was assessed by zeta potential measurement. Enzyme and pH-responsibility of CS-N NGs due to the presence of susceptible bonds in chondroitin sulfate resulted in effective and controlled release of nisin in the simulated infectious medium. Also, the ability of prepared CS-N NGs for eradicating clinical methicillin resistance S. aureus strain was confirmed by Broth Microdilution Method (BMD) and the cytotoxicity analysis was carried out on Human Dermal Fibroblast (HDF) cells by MTT assay method. Based on the results, this versatile drug carrier could efficiently deliver the cationic antimicrobial peptides as a natural antibiotic for growth inhibition of methicillin-resistant S. aureus strains and further destroying the bacteria in the treatment of subcutaneous infections caused by methicillin-resistant S. aureus strains.

Load phycocyanin to achieve in vivo imaging of casein-porous starch microgels induced by ultra-high-pressure homogenization

Traditional bioactive substances are often limited in practical application due to their poor stability and low solubility. Therefore, it is imperative to develop biocompatible high loading microgel carriers. In this study, a novel type of casein-porous starch microgel was prepared under ultra-high-pressure homogenization, by using porous starch with the honeycomb three-dimensional network porous structure. Molecular interaction force analysis and thermodynamic analysis showed that electrostatic interaction played a major role in the formation of microgels. Circular dichroism and Fourier transform infrared spectroscopy showed that homogenization and pH were the main factors, which affected the formation and structural stability of microgels. Compared with casein-glutinous rice starch microgels, the encapsulation efficiency and loading capacity of phycocyanin in casein-porous starch microgels were increased by 77.27% and 135.10%, respectively. Thus, casein-porous starch microgels could not only achieve a sustained release effect, but also effectively transport phycocyanin to the gastrointestinal tract of zebrafish, while achieving good fluorescence imaging in vivo. Ultimately, the prepared casein-porous starch microgels could enrich the nanocarriers material, and contribute to the research of safe and effective fluorescent imaging materials.

Advanced Hydrogels for the Controlled Delivery of Insulin

Insulin is a peptide hormone that is key to regulating physiological glucose levels. Its molecular size and susceptibility to conformational change under physiological pH make it challenging to orally administer insulin in diabetes. The most effective route for insulin delivery remains daily injection. Unfortunately, this results in poor patient compliance and increasing the risk of micro- and macro-vascular complications and thus rising morbidity and mortality rates in diabetics. The use of 3D hydrogels has been used with much interest for various biomedical applications. Hydrogels can mimic the extracellular matrix (ECM) and retain large quantities of water with tunable properties, which renders them suitable for administering a wide range of sensitive therapeutics. Several studies have demonstrated the fixation of insulin within the structural mesh of hydrogels as a bio-scaffold for the controlled delivery of insulin. This review provides a concise incursion into recent developments for the safe and effective controlled delivery of insulin using advanced hydrogel platforms with a special focus on sustained release injectable formulations. Various hydrogel platforms in terms of their methods of synthesis, properties, and unique features such as stimuli responsiveness for the treatment of Type 1 diabetes mellitus are critically appraised. Key criteria for classifying hydrogels are also outlined together with future trends in the field.

The impact of phosphatidylserine exposure on cancer cell membranes on the activity of the anticancer peptide HB43

HB43 (FAKLLAKLAKKLL) is a synthetic peptide active against cell lines derived from breast, colon, melanoma, lung, prostate, and cervical cancers. Despite its remarkable spectrum of activity, the mechanism of action at the molecular level has never been investigated, preventing further optimization of its selectivity. The alternation of charged and hydrophobic residues suggests amphipathicity, but the formation of alpha-helical structure seems discouraged by its short length and the large number of positively charged residues. Using different biophysical and in silico approaches we show that HB43 is completely unstructured in solution but assumes alpha-helical conformation in the presence of DPC micelles and liposomes exposing phosphatidylserine (PS) used as mimics of cancer cell membranes. Membrane permeabilization assays demonstrate that the interaction leads to the preferential destabilization of PS-containing vesicles with respect to PC-containing ones, here used as noncancerous cell mimics. ssNMR reveals that HB43 is able to fluidify the internal structure of cancer-cell mimicking liposomes while MD simulations show its internalization in such bilayers. This is achieved by the formation of specific interactions between the lysine side chains and the carboxylate group of phosphatidylserine and/or the phosphate oxygen atoms of targeted phospholipids, which could catalyze the formation of the alpha helix required for internalization. With the aim of better understanding the peptide biocompatibility and the additional antibacterial activity, the interaction with noncancerous cell mimicking liposomes exposing phosphatidylcholine (PC) and bacterial mimicking bilayers exposing phosphatidylglycerol (PG) is also described.

Polymer nano-systems for the encapsulation and delivery of active biomacromolecular therapeutic agents

Biomacromolecular therapeutic agents, particularly proteins, antigens, enzymes, and nucleic acids are emerging as powerful candidates for the treatment of various diseases and the development of the recent vaccine based on mRNA highlights the enormous potential of this class of drugs for future medical applications. However, biomacromolecular therapeutic agents present an enormous delivery challenge compared to traditional small molecules due to both a high molecular weight and a sensitive structure. Hence, the translation of their inherent pharmaceutical capacity into functional therapies is often hindered by the limited performance of conventional delivery vehicles. Polymer drug delivery systems are a modular solution able to address those issues. In this review, we discuss recent developments in the design of polymer delivery systems specifically tailored to the delivery challenges of biomacromolecular therapeutic agents. In the future, only in combination with a multifaceted and highly tunable delivery system, biomacromolecular therapeutic agents will realize their promising potential for the treatment of diseases and for the future of human health.

Nanoparticle-Guided Brain Drug Delivery: Expanding the Therapeutic Approach to Neurodegenerative Diseases

Neurodegenerative diseases (NDs) represent a heterogeneous group of aging-related disorders featured by progressive impairment of motor and/or cognitive functions, often accompanied by psychiatric disorders. NDs are denoted as 'protein misfolding' diseases or proteinopathies, and are classified according to their known genetic mechanisms and/or the main protein involved in disease onset and progression. Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD) are included under this nosographic umbrella, sharing histopathologically salient features, including deposition of insoluble proteins, activation of glial cells, loss of neuronal cells and synaptic connectivity. To date, there are no effective cures or disease-modifying therapies for these NDs. Several compounds have not shown efficacy in clinical trials, since they generally fail to cross the blood-brain barrier (BBB), a tightly packed layer of endothelial cells that greatly limits the brain internalization of endogenous substances. By engineering materials of a size usually within 1-100 nm, nanotechnology offers an alternative approach for promising and innovative therapeutic solutions in NDs. Nanoparticles can cross the BBB and release active molecules at target sites in the brain, minimizing side effects. This review focuses on the state-of-the-art of nanoengineered delivery systems for brain targeting in the treatment of AD, PD and HD.