Stealth properties to improve therapeutic efficacy of drug nanocarriers

Stealth Nanocarriers in Cancer Therapy: a Comprehensive Review of Design, Functionality, and Clinical Applications

Nanotechnology has significantly transformed cancer treatment by introducing innovative methods for delivering drugs effectively. This literature review provided an in-depth analysis of the role of nanocarriers in cancer therapy, with a particular focus on the critical concept of the 'stealth effect.' The stealth effect refers to the ability of nanocarriers to evade the immune system and overcome physiological barriers. The review investigated the design and composition of various nanocarriers, such as liposomes, micelles, and inorganic nanoparticles, highlighting the importance of surface modifications and functionalization. The complex interaction between the immune system, opsonization, phagocytosis, and the protein corona was examined to understand the stealth effect. The review carefully evaluated strategies to enhance the stealth effect, including surface coating with polymers, biomimetic camouflage, and targeting ligands. The in vivo behavior of stealth nanocarriers and their impact on pharmacokinetics, biodistribution, and toxicity were also systematically examined. Additionally, the review presented clinical applications, case studies of approved nanocarrier-based cancer therapies, and emerging formulations in clinical trials. Future directions and obstacles in the field, such as advancements in nanocarrier engineering, personalized nanomedicine, regulatory considerations, and ethical implications, were discussed in detail. The review concluded by summarizing key findings and emphasizing the transformative potential of stealth nanocarriers in revolutionizing cancer therapy. This review enhanced the comprehension of nanocarrier-based cancer therapies and their potential impact by providing insights into advanced studies, clinical applications, and regulatory considerations.

Nano-Engineering Strategies for Tumor-Specific Therapy

Nanodelivery systems (NDSs) provide promising prospects for decreasing drug doses, reducing side effects, and improving therapeutic effects. However, the bioapplications of NDSs are still compromised by their fast clearance, indiscriminate biodistribution, and limited tumor accumulation. Hence, engineering modification of NDSs aiming at promoting tumor-specific therapy and avoiding systemic toxicity is usually needed. An NDS integrating various functionalities, including flexible camouflage, specific biorecognition, and sensitive stimuli-responsiveness, into one sequence would be "smart" and highly effective. Herein, we systematically summarize the related principles, methods, and progress. At the end of the review, we predict the obstacles to precise nanoengineering and prospects for the future application of NDSs.

Fmoc-FF hydrogels and nanogels for improved and selective delivery of dexamethasone in leukemic cells and diagnostic applications

Dexamethasone (DEX) is a synthetic analogue of cortisol commonly used for the treatment of different pathological conditions, comprising cancer, ocular disorders, and COVID-19 infection. Its clinical use is hampered by the low solubility and severe side effects due to its systemic administration. The capability of peptide-based nanosystems, like hydrogels (HGs) and nanogels (NGs), to serve as vehicles for the passive targeting of active pharmaceutical ingredients and the selective internalization into leukemic cells has here been demonstrated. Peptide based HGs loaded with DEX were formulated via the "solvent-switch" method, using Fmoc-FF homopeptide as building block. Due to the tight interaction of the drug with the peptidic matrix, a significant stiffening of the gel (G' = 67.9 kPa) was observed. The corresponding injectable NGs, obtained from the sub-micronization of the HG, in the presence of two stabilizing agents (SPAN®60 and TWEEN®60, 48/52 w/w), were found to be stable up to 90 days, with a mean diameter of 105 nm. NGs do not exhibit hemolytic effects on human serum, moreover they are selectively internalized by RS4;11 leukemic cells over healthy PBMCs, paving the way for the generation of new diagnostic strategies targeting onco-hematological diseases.

A Clinical, Pharmacological, and Formulation Evaluation of Melatonin in the Treatment of Ocular Disorders-A Systematic Review

Melatonin's cytoprotective properties may have therapeutic implications in treating ocular diseases like glaucoma and age-related macular degeneration. Literature data suggest that melatonin could potentially protect ocular tissues by decreasing the production of free radicals and pro-inflammatory mediators. This study aims to summarize the screened articles on melatonin's clinical, pharmacological, and formulation evaluation in treating ocular disorders. The identification of relevant studies on the topic in focus was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines. The studies were searched in the following databases and web search engines: Pubmed, Scopus, Science Direct, Web of Science, Reaxys, Google Scholar, Google Patents, Espacenet, and Patentscope. The search time interval was 2013-2023, with the following keywords: melatonin AND ocular OR ophthalmic AND formulation OR insert AND disease. Our key conclusion was that using melatonin-loaded nano-delivery systems enabled the improved permeation of the molecule into intraocular tissues and assured controlled release profiles. Although preclinical studies have demonstrated the efficacy of developed formulations, a considerable gap has been observed in the clinical translation of the results. To overcome this failure, revising the preclinical experimental phase might be useful by selecting endpoints close to clinical ones.

Nanomaterials in Medicine: Understanding Cellular Uptake, Localization, and Retention for Enhanced Disease Diagnosis and Therapy

Nanomaterials (NMs) have emerged as promising tools for disease diagnosis and therapy due to their unique physicochemical properties. To maximize the effectiveness and design of NMs-based medical applications, it is essential to comprehend the complex mechanisms of cellular uptake, subcellular localization, and cellular retention. This review illuminates the various pathways that NMs take to get from the extracellular environment to certain intracellular compartments by investigating the various mechanisms that underlie their interaction with cells. The cellular uptake of NMs involves complex interactions with cell membranes, encompassing endocytosis, phagocytosis, and other active transport mechanisms. Unique uptake patterns across cell types highlight the necessity for customized NMs designs. After internalization, NMs move through a variety of intracellular routes that affect where they are located subcellularly. Understanding these pathways is pivotal for enhancing the targeted delivery of therapeutic agents and imaging probes. Furthermore, the cellular retention of NMs plays a critical role in sustained therapeutic efficacy and long-term imaging capabilities. Factors influencing cellular retention include nanoparticle size, surface chemistry, and the cellular microenvironment. Strategies for prolonging cellular retention are discussed, including surface modifications and encapsulation techniques. In conclusion, a comprehensive understanding of the mechanisms governing cellular uptake, subcellular localization, and cellular retention of NMs is essential for advancing their application in disease diagnosis and therapy. This review provides insights into the intricate interplay between NMs and biological systems, offering a foundation for the rational design of next-generation nanomedicines.

Peptide-Hydrogel Nanocomposites for Anti-Cancer Drug Delivery

Cancer is the second leading cause of death globally, but conventional anticancer drugs have side effects, mainly due to their non-specific distribution in the body in both cancerous and healthy cells. To address this relevant issue and improve the efficiency of anticancer drugs, increasing attention is being devoted to hydrogel drug-delivery systems for different kinds of cancer treatment due to their high biocompatibility and stability, low side effects, and ease of modifications. To improve the therapeutic efficiency and provide multi-functionality, different types of nanoparticles (NPs) can be incorporated within the hydrogels to form smart hydrogel nanocomposites, benefiting the advantages of both counterparts and suitable for advanced anticancer applications. Despite many papers on non-peptide hydrogel nanocomposites, there is limited knowledge about peptide-based nanocomposites, specifically in anti-cancer drug delivery. The aim of this short but comprehensive review is, therefore, to focus attention on the synergies resulting from the combination of NPs with peptide-based hydrogels. This review, which includes a survey of recent advances in this kind of material, does not aim to be an exhaustive review of hydrogel technology, but it instead highlights recent noteworthy publications and discusses novel perspectives to provide valuable insights into the promising synergic combination of peptide hydrogels and NPs for the design of novel anticancer drug delivery systems.

Biomimetic Systems Involving Macrophages and Their Potential for Targeted Drug Delivery

The concept of targeted drug delivery can be described in terms of the drug systems' ability to mimic the biological objects' property to localize to target cells or tissues. For example, drug delivery systems based on red blood cells or mimicking some of their useful features, such as long circulation in stealth mode, have been known for decades. On the contrary, therapeutic strategies based on macrophages have gained very limited attention until recently. Here, we review two biomimetic strategies associated with macrophages that can be used to develop new therapeutic modalities: first, the mimicry of certain types of macrophages (i.e., the use of macrophages, including tumor-associated or macrophage-derived particles as a carrier for the targeted delivery of therapeutic agents); second, the mimicry of ligands, naturally absorbed by macrophages (i.e., the use of therapeutic agents specifically targeted at macrophages). We discuss the potential applications of biomimetic systems involving macrophages for new advancements in the treatment of infections, inflammatory diseases, and cancer.

Zeta potential shifting nanoemulsions comprising single and gemini tyrosine-based surfactants

AIM

This study aims to design and evaluate zeta potential shifting nanoemulsions comprising single and gemini type tyrosine-based surfactants for specific cleavage by tyrosine phosphatase.

METHODS

Tyrosine-based surfactants, either single 4-(2-amino-3-(dodecylamino)-3-oxopropyl)phenyl dihydrogen phosphate (AF1) or gemini 4-(2-amino-3-((1-(dodecylamino)-3-(4-hydroxyphenyl)-1-oxopropan-2-yl)amino)-3-oxopropyl)phenyl dihydrogen phosphate (AF2) type were synthesized via amide bond formation of tyrosine with dodecylamine followed by phosphorylation. These surfactants were incorporated into nanoemulsions. Nanoemulsions were monitored by incubation with isolated tyrosine phosphatase as well as secreted tyrosine phosphatase of Escherichia coli in terms of phosphate release and zeta potential change.

RESULTS

Via isolated tyrosine phosphatase, and mediated by E. coli, phosphate groups of either single or gemini tyrosine-based surfactants could be cleaved by secreted tyrosine phosphatase. Nanoemulsions comprising a single tyrosine-based surfactant resulted in a charge shift from - 13.46 mV to - 4.41 mV employing isolated tyrosine phosphatase whilst nanoemulsions consisting of a gemini tyrosine-based surfactant showed a shift in zeta potential from - 15.92 mV to - 5.86 mV, respectively.

CONCLUSION

Nanoemulsions containing tyrosine-based surfactants represent promising zeta potential shifting nanocarrier systems targeting tyrosine phosphatase secreting bacteria.

Pharmacokinetics and Anti-Tumor Efficacy of PEGylated Liposomes Co-Loaded with Cisplatin and Mifepristone

Although cisplatin is an effective chemotherapy drug used against many types of cancer, it has poor bioavailability, produces severe adverse effects, and frequently leads to tumor resistance. Consequently, more effective formulations are needed. The co-administration of cisplatin with mifepristone, which counters an efflux pump drug-resistance mechanism in tumor cells, has shown important synergism, but without resolving the problem of poor bioavailability. Specificity to tumor tissue and bioavailability have been improved by co-encapsulating cisplatin and mifepristone in a liposomal formulation (L-Cis/MF), which needs further research to complete pre-clinical requirements. The aim of this current contribution was to conduct a pharmacokinetic study of cisplatin and mifepristone in male Wistar rats after administration of L-Cis/MF and the conventional (unencapsulated) formulation. Additionally, the capacity of L-Cis/MF to reduce tumor growth in male nude mice was evaluated following the implantation of xenografts of non-small-cell lung cancer. The better pharmacokinetics (higher plasma concentration) of cisplatin and mifepristone when injected in the liposomal versus the conventional formulation correlated with greater efficacy in controlling tumor growth. Future research on L-Cis/MF will characterize its molecular mechanisms and apply it to other types of cancer affected by the synergism of cisplatin and mifepristone.

Intracellular Fate of the Photosensitizer Chlorin e4 with Different Carriers and Induced Metabolic Changes Studied by 1H NMR Spectroscopy

Porphyrinic photosensitizers (PSs) and their nano-sized polymer-based carrier systems are required to exhibit low dark toxicity, avoid side effects, and ensure high in vivo tolerability. Yet, little is known about the intracellular fate of PSs during the dark incubation period and how it is affected by nanoparticles. In a systematic study, high-resolution magic angle spinning NMR spectroscopy combined with statistical analyses was used to study the metabolic profile of cultured HeLa cells treated with different concentrations of PS chlorin e4 (Ce4) alone or encapsulated in carrier systems. For the latter, either polyvinylpyrrolidone (PVP) or the micelle-forming polyethylene glycol (PEG)-polypropylene glycol triblock copolymer Kolliphor P188 (KP) were used. Diffusion-edited spectra indicated Ce4 membrane localization evidenced by Ce4 concentration-dependent chemical shift perturbation of the cellular phospholipid choline resonance. The effect was also visible in the presence of KP and PVP but less pronounced. The appearance of the PEG resonance in the cell spectra pointed towards cell internalization of KP, whereas no conclusion could be drawn for PVP that remained NMR-invisible. Multivariate statistical analyses of the cell spectra (PCA, PLS-DA, and oPLS) revealed a concentration-dependent metabolic response upon exposure to Ce4 that was attenuated by KP and even more by PVP. Significant Ce4-concentration-dependent alterations were mainly found for metabolites involved in the tricarboxylic acid cycle and the phosphatidylcholine metabolism. The data underline the important protective role of the polymeric carriers following cell internalization. Moreover, to our knowledge, for the first time, the current study allowed us to trace intracellular PS localization on an atomic level by NMR methods.

Tumor Eradication by Boron Neutron Capture Therapy with 10 B-enriched Hexagonal Boron Nitride Nanoparticles Grafted with Poly(Glycerol)

Boron neutron capture therapy (BNCT) has emerged as a treatment modality with high precision and efficacy of intractable tumors. At the core of effective tumor BNCT are 10 B carriers with facile preparation as well as advantageous pharmacokinetic and therapeutic profiles. Herein, the design and preparation of sub-10 nm 10 B-enriched hexagonal boron nitride nanoparticles grafted with poly(glycerol) (h-10 BN-PG), and their application to cancer treatment by BNCT are reported. By virtue of their small particle size and outstanding stealth property, h-10 BN-PG nanoparticles accumulate efficiently in murine CT26 colon tumors with a high intratumor 10 B concentration of 8.8%ID g-1 or 102.1 µg g-1 at 12 h post-injection. Moreover, h-10 BN-PG nanoparticles penetrate into the inside of the tumor parenchyma and then are taken up by the tumor cells. BNCT comprising a single bolus injection of h-10 BN-PG nanoparticles and subsequent one-time neutron irradiation results in significant shrinkage of subcutaneous CT26 tumors. h-10 BN-PG-mediated BNCT not only causes direct DNA damage to the tumor cells, but also triggers pronounced inflammatory immune response in the tumor tissues, which contributes to long-lasting tumor suppression after the neutron irradiation. Thus, the h-10 BN-PG nanoparticles are promising BNCT agents to eradicate tumor through highly efficient 10 B accumulation.

Design, strategies, and therapeutics in nanoparticle-based siRNA delivery systems for breast cancer

Utilizing small interfering RNA (siRNA) as a treatment for cancer, a disease largely driven by genetic aberrations, shows great promise. However, implementing siRNA therapy in clinical practice is challenging due to its limited bioavailability following systemic administration. An attractive approach to address this issue is the use of a nanoparticle (NP) delivery platform, which protects siRNA and delivers it to the cytoplasm of target cells. We provide an overview of design considerations for using lipid-based NPs, polymer-based NPs, and inorganic NPs to improve the efficacy and safety of siRNA delivery. We focus on the chemical structure modification of carriers and NP formulation optimization, NP surface modifications to target breast cancer cells, and the linking strategy and intracellular release of siRNA. As a practical example, recent advances in the development of siRNA therapeutics for treating breast cancer are discussed, with a focus on inhibiting cancer growth, overcoming drug resistance, inhibiting metastasis, and enhancing immunotherapy.

The immune-stealth polymeric coating on drug delivery nanocarriers: In vitro engineering and in vivo fate

Although essential nanosystems such as nanoparticles and nanocarriers are desirable options for transporting various drug molecules into the biological environment, they rapidly remove from the circulatory system due to their interaction with multiple in vivo barriers, especially the immune barrier, which will result in their short-term effects. In order to improve their effectiveness and durability in the circulatory system, the polymer coatings can use to cover the surface of nanoparticles and nanocarriers to conceal them from the immune system. Due to their different properties (like charge, elasticity, and hydrophilicity/hydrophobicity), these coatings can improve drug delivery nanosystem durability and therapeutic applications. The mentioned coatings have different types and are divided into various categories, such as synthetic polymers, polysaccharides, and zwitterionic polymers. Each of these polymers has unique properties based on its category, origin, and chemical structure that make them suitable for producing stealth drug delivery nanocarriers. In this review article, we have tried to explain the importance of these diverse polymer coatings in determining the fate of drug nanocarriers and then introduced the different types of these coatings and, finally, described various methods that directly and indirectly analyze the nanocoatings to determine the stability of nanoparticles in the body.

siRNA therapeutics: insights, challenges, remedies and future prospects

INTRODUCTION

Among conventional and novel therapeutic approaches, the siRNA strategy stands out for treating disease by silencing the gene responsible for the corresponding disorder. Gene silencing is supposedly intended to target any disease-causing gene, and therefore, several attempts and investments were made to exploit siRNA gene therapy and advance it into clinical settings. Despite the remarkable beneficial prospects, the applicability of siRNA therapeutics is very challenging due to various pathophysiological barriers that hamper its target reach, which is the cytosol, and execution of gene silencing action.

AREAS COVERED

The present review provides insights into the field of siRNA therapeutics, significant in vivo hurdles that mitigate the target accessibility of siRNA, and remedies to overcome these siRNA delivery challenges. Nonetheless, the current review also highlights the on-going clinical trials and the regulatory aspects of siRNA modalities.

EXPERT OPINION

The siRNAs have the potential to reach previously untreated target sites and silence the concerned gene owing to their modification as polymeric or lipidic nanoparticles, conjugates, and the application of advanced drug delivery strategies. With such mounting research attempts to improve the delivery of siRNA to target tissue, we might shortly witness revolutionary therapeutic outcomes, new approvals, and clinical implications.

Dextran 40 hybrid biomimetic bismuth-nanoflower designed for NIR II-triggered hypoxic tumor thermoradiotherapy via macrophage escape

At present, NIR-II-triggered photothermal biomedical applications are limited by complex synthesis reactions, mediocre photothermal conversion efficiency, and difficult degradation. Herein, we prepared biodegradable Bi flower-like nanoparticles (phospholipid-modified Bi nanoflowers, BNFs) with high photothermal conversion efficiency (∼33.52 %) in NIR-II by a simple method and then modified them with the red blood cell membrane and dextran 40 (DRBCM) to improve their in vitro stability, to escape macrophages clearance and to enhance tumor accumulation. Dextran coating onto the surface of particles as a dispersant shell stabilizes inorganic particles by maintaining the surface charges and creating steric repulsions upon compression of neighboring polymer chains. In vitro and in vivo experiments proved that combined thermoradiotherapy of DRBCM-BNFs exhibited significantly enhanced tumor inhibition efficacy than monotherapy with good biocompatibility and low toxicity due to its biodegradability. Furthermore, the mechanism studies demonstrated that DRBCM-BNFs could serve as a nano sensitizer to promote the thermoradiotherapy under NIR-II illumination and X-ray irradiation, by downregulating heat shock protein 70 (HSP70) and phosphorylated-p65 (p-p65) to reduce the thermal resistance and radioresistance of tumor cells and increasing the expression of apoptosis-related protein cleaved caspase-3. In conclusion, DRBCM-BNFs could be a promising green delivery platform for the sensitization of synergistic thermoradiotherapy.

Hyaluronic Acid-Based Nanosystems for CD44 Mediated Anti-Inflammatory and Antinociceptive Activity

The nervous and immune systems go hand in hand in causing inflammation and pain. However, the two are not mutually exclusive. While some diseases cause inflammation, others are caused by it. Macrophages play an important role in modulating inflammation to trigger neuropathic pain. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan that has a well-known ability to bind with the cluster of differentiation 44 (CD44) receptor on classically activated M1 macrophages. Resolving inflammation by varying the molecular weight of HA is a debated concept. HA-based drug delivery nanosystems such as nanohydrogels and nanoemulsions, targeting macrophages can be used to relieve pain and inflammation by loading antinociceptive drugs and enhancing the effect of anti-inflammatory drugs. This review will discuss the ongoing research on HA-based drug delivery nanosystems regarding their antinociceptive and anti-inflammatory effects.

Structural and mechanical properties of folded protein hydrogels with embedded microbubbles

Globular folded proteins are powerful building blocks to create biomaterials with mechanical robustness and inherent biological functionality. Here we explore their potential as advanced drug delivery scaffolds, by embedding microbubbles (MBs) within a photo-activated, chemically cross-linked bovine serum albumin (BSA) protein network. Using a combination of circular dichroism (CD), rheology, small angle neutron scattering (SANS) and microscopy we determine the nanoscale and mesoscale structure and mechanics of this novel multi-composite system. Optical and confocal microscopy confirms the presence of MBs within the protein hydrogel, their reduced diffusion and their effective rupture using ultrasound, a requirement for burst drug release. CD confirms that the inclusion of MBs does not impact the proportion of folded proteins within the cross-linked protein network. Rheological characterisation demonstrates that the mechanics of the BSA hydrogels is reduced in the presence of MBs. Furthermore, SANS reveals that embedding MBs in the protein hydrogel network results in a smaller number of clusters that are larger in size (∼16.6% reduction in number of clusters, 17.4% increase in cluster size). Taken together, we show that MBs can be successfully embedded within a folded protein network and ruptured upon application of ultrasound. The fundamental insight into the impact of embedded MBs in protein scaffolds at the nanoscale and mesoscale is important in the development of future platforms for targeted and controlled drug delivery applications.

Caveolin-Mediated Internalization of Fmoc-FF Nanogels in Breast Cancer Cell Lines

INTRODUCTION

Hydrogel nanoparticles, also known as nanogels (NGs), have been recently proposed as alternative supramolecular vehicles for the delivery of biologically relevant molecules like anticancer drugs and contrast agents. The inner compartment of peptide based NGs can be opportunely modified according to the chemical features of the cargo, thus improving its loading and release. A full understanding of the intracellular mechanism involved in nanogel uptake by cancer cells and tissues would further contribute to the potential diagnostic and clinical applications of these nanocarriers, allowing the fine tuning of their selectivity, potency, and activity. The structural characterization of nanogels were assessed by Dynamic Light Scattering (DLS) and Nanoparticles Tracking Analysis (NTA) analysis. Cells viability of Fmoc-FF nanogels was evaluated by MTT assay on six breast cancer cell lines at different incubation times (24, 48, and 72 h) and peptide concentrations (in the range 6.25 × 10^-4 ÷ 5·10^-3 × wt%). The cell cycle and mechanisms involved in Fmoc-FF nanogels intracellular uptake were evaluated using flow cytometry and confocal analysis, respectively. Fmoc-FF nanogels, endowed with a diameter of ~130 nm and a zeta potential of ~-20.0/-25.0 mV, enter cancer cells via caveolae, mostly those responsible for albumin uptake. The specificity of the machinery used by Fmoc-FF nanogels confers a selectivity toward cancer cell lines overexpressing the protein caveolin1 and efficiently performing caveolae-mediated endocytosis.

Recent advances in long-acting drug delivery systems for anticancer drug

The use of systemic anticancer chemotherapy is intrinsically limited by its toxicity. Whether dealing with small molecules or biopharmaceuticals, after systemic administration, small doses fail to reach effective intratumoral concentrations, while high doses with significant tumor inhibition effects may also drive the death of healthy cells, endangering the patients. Therefore, strategies based on drug delivery systems (DDSs) for avoiding the systemic toxicity have been designed. Due to their ability to protect drugs from early elimination and control drug release, DDSs can foster tumor exposure to anticancer therapeutics by extending their circulation time or steadily releasing drugs into the tumor sites. However, approval of tailored DDSs systems for clinical use is minimal as the safety and the in vivo activity still need to be ameliorated by manipulating their physicochemical characteristics. During the last few years, several strategies have been described to improve their safety, stability, and fine-tune pharmaceuticals release kinetics. Herein, we reviewed the main DDSs, namely polymeric conjugates, nano or microparticles, hydrogels, and microneedles, explored for long-acting anticancer treatments, highlighting recently proposed modifications and their potential advantages for different anticancer therapies. Additionally, important limitations of long-acting anticancer therapies and future technology directions were also covered.

A review on microfluidic-assisted nanoparticle synthesis, and their applications using multiscale simulation methods

Recent years have witnessed an increased interest in the development of nanoparticles (NPs) owing to their potential use in a wide variety of biomedical applications, including drug delivery, imaging agents, gene therapy, and vaccines, where recently, lipid nanoparticle mRNA-based vaccines were developed to prevent SARS-CoV-2 causing COVID-19. NPs typically fall into two broad categories: organic and inorganic. Organic NPs mainly include lipid-based and polymer-based nanoparticles, such as liposomes, solid lipid nanoparticles, polymersomes, dendrimers, and polymer micelles. Gold and silver NPs, iron oxide NPs, quantum dots, and carbon and silica-based nanomaterials make up the bulk of the inorganic NPs. These NPs are prepared using a variety of top-down and bottom-up approaches. Microfluidics provide an attractive synthesis alternative and is advantageous compared to the conventional bulk methods. The microfluidic mixing-based production methods offer better control in achieving the desired size, morphology, shape, size distribution, and surface properties of the synthesized NPs. The technology also exhibits excellent process repeatability, fast handling, less sample usage, and yields greater encapsulation efficiencies. In this article, we provide a comprehensive review of the microfluidic-based passive and active mixing techniques for NP synthesis, and their latest developments. Additionally, a summary of microfluidic devices used for NP production is presented. Nonetheless, despite significant advancements in the experimental procedures, complete details of a nanoparticle-based system cannot be deduced from the experiments alone, and thus, multiscale computer simulations are utilized to perform systematic investigations. The work also details the most common multiscale simulation methods and their advancements in unveiling critical mechanisms involved in nanoparticle synthesis and the interaction of nanoparticles with other entities, especially in biomedical and therapeutic systems. Finally, an analysis is provided on the challenges in microfluidics related to nanoparticle synthesis and applications, and the future perspectives, such as large-scale NP synthesis, and hybrid formulations and devices.

Probing the Biocompatibility and Immune Cell Association of Chiral, Water-Soluble, Bottlebrush Poly(2-oxazoline)s

Poly(2-oxazoline)s (POx) have received substantial attention as poly(ethylene glycol) (PEG) alternatives in the biomedical field due to their biocompatibility, high functionality, and ease of synthesis. While POx have demonstrated strong potential as biomaterial constituents, the larger family of poly(cyclic imino ether)s (PCIE) to which POx belongs remains widely underexplored. One highly interesting sub-class of PCIE is poly(2,4-disubstituted-2-oxazoline)s (PdOx), which bear an additional substituent on the backbone of the polymers' repeating units. This allows fine-tuning of the hydrophilic/hydrophobic balance and renders the PdOx chiral when enantiopure 2-oxazoline monomers are used. Herein, we synthesize new water-soluble (R-/S-/RS-) poly(oligo(2-ethyl-4-methyl-2-oxazoline) methacrylate) (P(OEtMeOxMA)) bottlebrushes and compare them to well-established PEtOx- and PEG-based bottlebrush controls in terms of their physical properties, hydrophilicity, and biological behavior. We reveal that the P(OEtMeOxMA) bottlebrushes show a lower critical solution temperature behavior at a physiologically relevant temperature (∼44 °C) and that the enantiopure (R-/S-) variants display a chiral secondary structure. Importantly, we demonstrate the biocompatibility of the chiral P(OEtMeOxMA) bottlebrushes through cellular association and mouse biodistribution studies and show that these systems display higher immune cell association and organ accumulation than the two control polymers. These novel materials possess properties that hold promise for applications in the field of nanomedicine and may be beneficial carriers for therapeutics that require enhanced cellular association and immune cell interaction.

Nano-drug delivery system for pancreatic cancer: A visualization and bibliometric analysis

Background: Nano drug delivery system (NDDS) can significantly improve the delivery and efficacy of drugs against pancreatic cancer (PC) in many ways. The purpose of this study is to explore the related research fields of NDDS for PC from the perspective of bibliometrics.

Methods: Articles and reviews on NDDS for PC published between 2003 and 2022 were obtained from the Web of Science Core Collection. CiteSpace, VOSviewer, R-bibliometrix, and Microsoft Excel were comprehensively used for bibliometric and visual analysis.

Results: A total of 1329 papers on NDDS for PC were included. The number of papers showed an upward trend over the past 20 years. The United States contributed the most papers, followed by China, and India. Also, the United States had the highest number of total citations and H-index. The institution with the most papers was Chinese Acad Sci, which was also the most important in international institutional cooperation. Professors Couvreur P and Kazuoka K made great achievements in this field. JOURNAL OF CONTROLLED RELEASE published the most papers and was cited the most. The topics related to the tumor microenvironment such as “tumor microenvironment”, “tumor penetration”, “hypoxia”, “exosome”, and “autophagy”, PC treatment-related topics such as “immunotherapy”, “combination therapy”, “alternating magnetic field/magnetic hyperthermia”, and “ultrasound”, and gene therapy dominated by “siRNA” and “miRNA” were the research hotspots in the field of NDDS for PC.

Conclusion: This study systematically uncovered a holistic picture of the performance of NDDS for PC-related literature over the past 20 years. We provided scholars to understand key information in this field with the perspective of bibliometrics, which we believe may greatly facilitate future research in this field.

PEG Spacer Length Substantially Affects Antibody-Based Nanocarrier Targeting of Dendritic Cell Subsets

Successful cell targeting depends on the controlled positioning of cell-type-specific antibodies on the nanocarrier’s (NC) surface. Uncontrolled antibody immobilization results in unintended cell uptake due to Fc-mediated cell interaction. Consequently, precise immobilization of the Fc region towards the nanocarrier surface is needed with the Fab regions staying freely accessible for antigen binding. Moreover, the antibody needs to be a certain distance from the nanocarrier surface, influencing the targeting performance after formation of the biomolecular corona. This can be achieved by using PEG linker molecules. Here we demonstrate cell type-specific targeting for dendritic cells (DC) as cellular key regulators of immune responses. However, to date, dendritic cell targeting experiments using different linker lengths still need to be conducted. Consequently, we focused on the surface modification of nanocarriers with different molecular weight PEG linkers (0.65, 2, and 5 kDa), and their ability to reduce undesired cell uptake, while achieving efficient DC targeting via covalently immobilized antibodies (stealth targeting). Our findings demonstrate that the PEG linker length significantly affects active dendritic cell targeting from cell lines (DC2.4) to primary cells (BMDCs, splenocytic conventional DCs type 1 (cDC1)). While antibody-functionalized nanocarriers with a shorter PEG length (0.65 kDa) showed the best targeting in DC2.4, a longer PEG length (5 kDa) was required to specifically accumulate in BMDCs and splenocytic cDC1. Our study highlights that these crucial aspects must be considered when targeting dendritic cell subsets, which are of great importance in the fields of cancer immunotherapy and vaccine development.

Review: New horizons in retinoblastoma treatment: an updated review article

Retinoblastoma (Rb) is a rare childhood intraocular malignancy with an incidence rate of approximately 9000 children per year worldwide. The management of Rb is inherently complex and depends on several factors. The orders of priorities in the treatment of Rb are saving life, globe salvage and vision salvage. Rarity and the young age at diagnosis impede conducting randomized clinical trials (RCTs) for new therapeutic options, and therefore pre-RCTs studies are needed. This review provides an overview of advances in Rb treatment options, focusing on the emergence of new small molecules to treat Rb. Articles related to the management and treatments of Rb were searched in different databases. Several studies and animal models discussing recent advances in the treatment of Rb were included to have a better grasp of the biological mechanisms of Rb. Over the years, the principles of management and treatment of Rb have changed significantly. Innovations in targeted therapies and molecular biology have led to improved patient and ocular survival. However, there is still a need for further evaluation of the long-term effects of these new treatments.

Micro/Nanosystems for Magnetic Targeted Delivery of Bioagents

Targeted delivery of pharmaceuticals is promising for efficient disease treatment and reduction in adverse effects. Nano or microstructured magnetic materials with strong magnetic momentum can be noninvasively controlled via magnetic forces within living beings. These magnetic carriers open perspectives in controlling the delivery of different types of bioagents in humans, including small molecules, nucleic acids, and cells. In the present review, we describe different types of magnetic carriers that can serve as drug delivery platforms, and we show different ways to apply them to magnetic targeted delivery of bioagents. We discuss the magnetic guidance of nano/microsystems or labeled cells upon injection into the systemic circulation or in the tissue; we then highlight emergent applications in tissue engineering, and finally, we show how magnetic targeting can integrate with imaging technologies that serve to assist drug delivery.

Synthesis, characterisation and evaluation of hyperbranched N-(2-hydroxypropyl) methacrylamides for transport and delivery in pancreatic cell lines in vitro and in vivo

Hyperbranched polymers have many promising features for drug delivery, owing to their ease of synthesis, multiple functional group content, and potential for high drug loading with retention of solubility. Here we prepared hyperbranched N-(2-hydroxypropyl)methacrylamide (HPMA) polymers with a range of molar masses and particle sizes, and with attached dyes, radiolabel or the anticancer drug gemcitabine. Reversible addition-fragmentation chain transfer (RAFT) polymerisation enabled the synthesis of pHPMA polymers and a gemcitabine-comonomer functionalised pHPMA polymer pro-drug, with diameters of the polymer particles ranging from 7-40 nm. The non-drug loaded polymers were well-tolerated in cancer cell lines and macrophages, and were rapidly internalised in 2D cell culture and transported efficiently to the centre of dense pancreatic cancer 3D spheroids. The gemcitabine-loaded polymer pro-drug was found to be toxic both to 2D cultures of MIA PaCa-2 cells and also in reducing the volume of MIA PaCa-2 spheroids. The non-drug loaded polymers caused no short-term adverse effects in healthy mice following systemic injection, and derivatives of these polymers labelled with ⁸⁹Zr-were tracked for their distribution in the organs of healthy and MIA PaCa-2 xenograft bearing Balb/c nude mice. Tumour accumulation, although variable across the samples, was highest in individual animals for the pHPMA polymer of ∼20 nm size, and accordingly a gemcitabine pHPMA polymer pro-drug of ∼18 nm diameter was evaluated for efficacy in the tumour-bearing animals. The efficacy of the pHPMA polymer pro-drug was very similar to that of free gemcitabine in terms of tumour growth retardation, and although there was a survival benefit after 70 days for the polymer pro-drug, there was no difference at day 80. These data suggest that while polymer pro-drugs of this type can be effective, better tumour targeting and enhanced in situ release remain as key obstacles to clinical translation even for relatively simple polymers such as pHPMA.

Curcumin and Paclitaxel co-Loaded Heparin and Poloxamer P403 Hybrid Nanocarrier for Improved Synergistic Efficacy in Breast Cancer

Introduction:

Multi-drug nanosystem has been employed in several therapeutic models due to the synergistic effect of the drugs and/or bioactive compounds, which help in tumor-targeting and limit usual side effects of chemotherapy.

Methods:

In this research, we developed the amphiphilic Heparin-Poloxamer P403 (HSP) nanogel that can load curcumin (CUR) and Paclitaxel (PTX) through the hydrophobic core of Poloxamer P403. The features of HSP nanogel are assessed through Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), differential light scattering (DLS), and critical micelle concentration (CMC). Nanogel and its duel-loaded platform show high stability and spherical morphology.

Results:

The drug release profile indicates fast release at pH 5.5, suggesting effective drug distribution at the tumor site. In vitro research confirms lower cytotoxicity of HSP@CUR@PTX compared with free PTX and higher inhibition effect with MCF-7 than HSP@PTX. These results support the synergism between PTX and CUR.

Conclusion,:

HSP@CUR@PTX suggests a prominent strategy for achieving the synergistic effect of PTX and CUR to circumvent undesirable effects in breast cancer treatment.

The advances in nanomedicine for bone and cartilage repair

With the gradual demographic shift toward an aging and obese society, an increasing number of patients are suffering from bone and cartilage injuries. However, conventional therapies are hindered by the defects of materials, failing to adequately stimulate the necessary cellular response to promote sufficient cartilage regeneration, bone remodeling and osseointegration. In recent years, the rapid development of nanomedicine has initiated a revolution in orthopedics, especially in tissue engineering and regenerative medicine, due to their capacity to effectively stimulate cellular responses on a nanoscale with enhanced drug loading efficiency, targeted capability, increased mechanical properties and improved uptake rate, resulting in an improved therapeutic effect. Therefore, a comprehensive review of advancements in nanomedicine for bone and cartilage diseases is timely and beneficial. This review firstly summarized the wide range of existing nanotechnology applications in the medical field. The progressive development of nano delivery systems in nanomedicine, including nanoparticles and biomimetic techniques, which are lacking in the current literature, is further described. More importantly, we also highlighted the research advancements of nanomedicine in bone and cartilage repair using the latest preclinical and clinical examples, and further discussed the research directions of nano-therapies in future clinical practice.

Comparative Investigation of Cellular Effects of Polyethylene Glycol (PEG) Derivatives

Nowadays, polyethylene glycols referred to as PEGs are widely used in cosmetics, consumer care products, and the pharmaceutical industry. Their advantageous properties such as chemical stability, low immunogenicity, and high tolerability explain why PEGs are applied in many fields of pharmaceutical formulations including parenteral, topical, ophthalmic, oral, and rectal preparations and also in modern drug delivery systems. Given their extensive use, they are considered a well-known group of chemicals. However, the number of large-scale comparative studies involving multiple PEGs of wide molecular weight range is low, as in most cases biological effects are estimated upon molecular weight. The aim of this publication was to study the action of PEGs on Caco-2 cells and G. mellonella larvae and to calculate the correlation of these effects with molecular weight and osmolality. Eleven PEGs of different molecular weight were used in our experiments: PEG 200, PEG 300, PEG 400, PEG 600, PEG 1000, PEG 1500, PEG 4000, PEG 8000, PEG 10,000, 12,000, and PEG 20,000. The investigated cellular effects included cytotoxicity (MTT and Neutral Red assays, flow cytometry with propidium iodide and annexin V) and autophagy. The osmolality of different molecular weight PEGs with various concentrations was measured by a vapor pressure osmometer OSMOMAT 070 and G. mellonella larvae were injected with the solutions of PEGs. Sorbitol was used as controls of the same osmolality. Statistical correlation was calculated to describe the average molecular weight dependence of the different measured effects. Osmolality, the cytotoxicity assays, flow cytometry data, and larvae mortality had significant correlation with the structure of the PEGs, while autophagosome formation and the proportion of early apoptotic cells showed no statistical correlation. Overall, it must be noted that PEGs must be tested individually for biological effects as not all effects can be estimated by the average molecular weight.

Angiopoietin-1 Mimetic Nanoparticles for Restoring the Function of Endothelial Cells as Potential Therapeutic for Glaucoma

A root cause for the development and progression of primary open-angle glaucoma might be the loss of the Schlemm’s canal (SC) cell function due to an impaired Angiopoietin-1 (Angpt-1)/Tie2 signaling. Current therapeutic options fail to restore the SC cell function. We propose Angpt-1 mimetic nanoparticles (NPs) that are intended to bind in a multivalent manner to the Tie2 receptor for successful receptor activation. To this end, an Angpt-1 mimetic peptide was coupled to a poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) block co-polymer. The modified polymer allowed for the fabrication of Angpt-1 mimetic NPs with a narrow size distribution (polydispersity index < 0.2) and the size of the NPs ranging from about 120 nm (100% ligand density) to about 100 nm (5% ligand density). NP interaction with endothelial cells (HUVECs, EA.hy926) as surrogate for SC cells and fibroblasts as control was investigated by flow cytometry and confocal microscopy. The NP–cell interaction strongly depended on the ligand density and size of NPs. The cellular response to the NPs was investigated by a Ca²⁺ mobilization assay as well as by a real-time RT-PCR and Western blot analysis of endothelial nitric oxide synthase (eNOS). NPs with a ligand density of 25% opposed VEGF-induced Ca²⁺ influx in HUVECs significantly which could possibly increase cell relaxation and thus aqueous humor drainage, whereas the expression and synthesis of eNOS was not significantly altered. Therefore, we suggest Angpt-1 mimetic NPs as a first step towards a causative therapy to recover the loss of SC cell function during glaucoma.

An insight into the role of liposomal therapeutics in the reversion of Multiple Sclerosis

INTRODUCTION

Multiple Sclerosis (MS), as an autoimmune disease, has complicated immunopathology, which makes its management relevant to various factors. Novel pharmaceutical vehicles, especially liposomes, can support efficacious handling of this disease both in early detection and prognosis and also in a therapeutic manner. The most well-known trigger of MS onset is the predominance of cellular to humoral immunity and enhancement of inflammatory cytokines level. The installation of liposomes as nanoparticles to control this disease holds great promise up to now.

AREAS COVERED

Various types of liposomes with different properties and purposes have been formulated and targeted immune cells with their surface manipulations. They may be encapsulated with anti-inflammatory, MS-related therapeutics, or immunodominant myelin-specific peptides for attaining a higher therapeutic efficacy of the drugs or tolerance induction. Cationic liposomes are also highly applicable for gene delivery of the anti-inflammatory cytokines or silencing the inflammatory cytokines. Liposomes have also been used as biotools for comprehending MS pathomechanisms or as diagnostic agents.

EXPERT OPINION

The efforts to manage MS through nanomedicine, especially liposomal therapeutics, pave a new avenue to a high-throughput medication of this autoimmune disease and their translation to the clinic in the future for overcoming the challenges that MS patients confront.

Nanotechnology Based Approaches in Phage Therapy: Overcoming the Pharmacological Barriers

With the emergence and spread of global antibiotic resistance and the need for searching safer alternatives, there has been resurgence in exploring the use of bacteriophages in the treatment of bacterial infections referred as phage therapy. Although modern phage therapy has come a long way as demonstrated by numerous efficacy studies but the fact remains that till date, phage therapy has not received regulatory approval for human use (except for compassionate use).Thus, to hit the clinical market, the roadblocks need to be seriously addressed and gaps mended with modern solution based technologies. Nanotechnology represents one such ideal and powerful tool for overcoming the pharmacological barriers (low stability, poor in-vivo retention, targeted delivery, neutralisation by immune system etc.) of administered phage preparations.In literature, there are many review articles on nanotechnology and bacteriophages but these are primarily focussed on highlighting the use of lytic and temperate phages in different fields of nano-medicine such as nanoprobes, nanosensors, cancer diagnostics, cancer cell targeting, drug delivery through phage receptors, phage display etc. Reviews specifically focused on the use of nanotechnology driven techniques strictly to improve phage therapy are however limited. Moreover, these review if present have primarily focussed on discussing encapsulation as a primary method for improving the stability and retention of phage(s) in the body.With new advances made in the field of nanotechnology, approaches extend from mere encapsulation to recently adopted newer strategies. The present review gives a detailed insight into the more recent strategies which include 1) use of lipid based nano-carriers (liposomes, transfersomes etc.) 2) adopting microfluidic based approach, surface modification methods to further enhance the efficiency and stability of phage loaded liposomes 3) Nano- emulsification approach with integration of microfluidics for producing multiple emulsions (suitable for phage cocktails) with unique control over size, shape and drop morphology 4) Phage loaded nanofibers produced by electro-spinning and advanced core shell nanofibers for immediate, biphasic and delayed release systems and 5) Smart release drug delivery platforms that allow superior control over dosing and phage release as and when required. All these new advances are aimed at creating a suitable housing system for therapeutic bacteriophage preparations while targeting the multiple issues of phage therapy i.e., improving phage stability and titers, improving in-vivo retention times, acting as suitable delivery systems for sustained release at target site of infection, improved penetration into biofilms and protection from immune cell attack. The present review thus aims at giving a complete insight into the recent advances (2010 onwards) related to various nanotechnology based approaches to address the issues pertaining to phage therapy. This is essential for improving the overall therapeutic index and success of phage therapy for future clinical approval.

Ultrasound augments on-demand breast tumor radiosensitization and apoptosis through a tri-responsive combinatorial delivery theranostic platform

Advanced inoperable triple-negative breast cancer (TNBC) comprises aggressive tumors with a modest pathological response to neoadjuvant chemotherapy. The concomitant use of chemoradiotherapy improves the pathological response rates. However, the dose-dependent systemic toxicity of clinical radiosensitizers with poor circulation half-life and limited passive bioavailability limits their clinical utility. We address these challenges by rationally designing a stealth and tumor microenvironment responsive nano-conjugate platform for the ultrasound-mediated on-demand spatio-temporal delivery of plant flavonoid curcumin as a combinatorial regimen with clinically approved paclitaxel for the neoadjuvant chemoradiotherapy of locally advanced triple-negative breast cancer (TNBC). Interestingly, the focused application of ultrasound at the orthotopic TNBC xenograft of NOD-SCID mice facilitated the immediate infiltration of nano-conjugates at the tumor interstitium, and conferred in vivo safety over marketed paclitaxel formulation. In addition, curcumin significantly potentiated the in vivo chemoradiotherapeutic efficacy of paclitaxel upon loading into nano-conjugates. This gets further enhanced by the concurrent pulse of ultrasound, as confirmed by PET-CT imaging, along with a significant improvement in the mice survival. The quadrapeutic apoptotic effect by the combination of paclitaxel, curcumin, radiation, and ultrasound, along with a reduction in the tumor microvessel density and cell proliferation marker, confers the broad chemo-radiotherapeutic potential of this regimen for radio-responsive solid tumors, as well as metastatic niches.

Lung Targeted Lipopolymeric Microspheres of Dexamethasone for the Treatment of ARDS

Acute respiratory distress syndrome (ARDS), a catastrophic illness of multifactorial etiology, involves a rapid upsurge in inflammatory cytokines that leads to hypoxemic respiratory failure. Dexamethasone, a synthetic corticosteroid, mitigates the glucocorticoid-receptor-mediated inflammation and accelerates tissue homeostasis towards disease resolution. To minimize non-target organ side effects arising from frequent and chronic use of dexamethasone, we designed biodegradable, lung-targeted microspheres with sustained release profiles. Dexamethasone-loaded lipopolymeric microspheres of PLGA (Poly Lactic-co-Glycolic Acid) and DPPC (Dipalmitoylphosphatidylcholine) stabilized with vitamin E TPGS (D-α-tocopheryl polyethylene glycol succinate) were prepared by a single emulsion technique that had a mean diameter of 8.83 ± 0.32 μm and were spherical in shape as revealed from electron microscopy imaging. Pharmacokinetic and biodistribution patterns studied in the lungs, liver, and spleen of Wistar rats showed high selectivity and targeting efficiency for the lung tissue (re 13.98). As a proof-of-concept, in vivo efficacy of the microspheres was tested in the lipopolysaccharide-induced ARDS model in rats. Inflammation markers such as IL-1β, IL-6, and TNF-α, quantified in the bronchoalveolar lavage fluid indicated major improvement in rats treated with dexamethasone microspheres by intravenous route. Additionally, the microspheres substantially inhibited the protein infiltration, neutrophil accumulation and lipid peroxidation in the lungs of ARDS bearing rats, suggesting a reduction in oxidative stress. Histopathology showed decreased damage to the pulmonary tissue upon treatment with the dexamethasone-loaded microspheres. The multipronged formulation technology approach can thus serve as a potential treatment modality for reducing lung inflammation in ARDS. An improved therapeutic profile would help to reduce the dose, dosing frequency and, eventually, the toxicity.

Atorvastatin-loaded solid lipid nanoparticles as eye drops: proposed treatment option for age-related macular degeneration (AMD)

Statins, widely prescribed for cardiovascular diseases, are also being eyed for management of age-related macular degeneration (AMD). Poor bioavailability and blood-aqueous barrier may however limit significant ocular concentration of statins following oral administration. We for the first time propose and investigate local application of atorvastatin (ATS; representative statin) loaded into solid lipid nanoparticles (SLNs), as self-administrable eye drops. Insolubility, instability, and high molecular weight > 500 of ATS, and ensuring that SLNs reach posterior eye were the challenges to be met. ATS-SLNs, developed (2339/DEL/2014) using suitable components, quality-by-design (QBD) approach, and scalable hot high-pressure homogenization, were characterized and evaluated comprehensively for ocular suitability. ATS-SLNs were 8 and 12 times more bioavailable (AUC) in aqueous and vitreous humor, respectively, than free ATS. Three-tier (in vitro, ex vivo, and in vivo) ocular safety, higher corneal flux (2.5-fold), and improved stability (13.62 times) including photostability of ATS on incorporation in ATS-SLNs were established. Autoclavability and aqueous nature are the other highlights of ATS-SLNs. Presence of intact fluorescein-labeled SLNs (F-SLNs) in internal eye tissues post–in vivo application as eye drops provides direct evidence of successful delivery. Perinuclear fluorescence in ARPE-19 cells confirms the effective uptake of F-SLNs. Prolonged residence, up to 7 h, was attributed to the mucus-penetrating nature of ATS-SLNs.

Applications of Exosomes in Targeted Drug Delivery for the Treatment of Parkinson's Disease: A Review of Recent Advances and Clinical Challenges

Parkinson's disease (PD) is one of the most prevalent and severe neurodegenerative disease affecting more than 6.1 million people globally. It is characterized by age-related progressive deterioration of neurological functions caused by neuronal damage or neuronal death. During PD, the dopamineproducing cells in the substantia nigra region of the brain degenerate, which leads to symptoms like resting tremors and rigidity. Treatment of PD is very challenging due to the blood-brain barrier, which restricts the drug from reaching the brain. Conventional drug delivery systems possess a limited capacity to cross the blood barrier, leading to low bioavailability and high toxicity (due to off-site drug release). Therefore, it becomes necessary to accelerate the development of novel drug delivery systems, including nanoparticles, microemulsions, matrix systems, solid dispersions, liposomes, and solid lipid nanoparticles for the treatment of PD. Exosomes are biological lipid bilayer membrane vesicles produced by nearly all mammalian cells. The characteristics of vesicles are unique to their cell of origin and are primarily involved in intracellular communication. Exosomes, due to their nanoscale size, could easily permeate across the central nervous system, which makes them ideal for targeting the neurons in the substantia nigra. Exosomes could be efficient drug carrier systems for brain targeting, which can increase the efficacy of the drug and minimize the side effects. The review aims at providing a broad updated view of exosomes and their application in the treatment of PD.

Effects of Surface Charge, PEGylation and Functionalization with Dipalmitoylphosphatidyldiglycerol on Liposome-Cell Interactions and Local Drug Delivery to Solid Tumors via Thermosensitive Liposomes

Purpose

Previous studies demonstrated the possibility of targeting tumor-angiogenic endothelial cells with positively charged nanocarriers, such as cationic liposomes. We investigated the active targeting potential of positively charged nanoparticles in combination with the heat-induced drug release function of thermosensitive liposomes (TSL). This novel dual-targeted approach via cationic TSL (CTSL) was thoroughly explored using either a novel synthetic phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphodiglycerol (DPPG₂) or a conventional polyethylene glycol (PEG) surface modification. Anionic particles containing either DPPG₂ or PEG were also included in the study to highlight difference in tumor enrichment driven by surface charge. With this study, we aim to provide a deep insight into the main differences between DPPG₂- and PEG-functionalized liposomes, focusing on the delivery of a well-known cytotoxic drug (doxorubicin; DOX) in combination with local hyperthermia (HT, 41–43°C).

Materials and Methods

DPPG₂- and PEG-based cationic TSLs (PG₂-CTSL/PEG-CTSL) were thoroughly analyzed for size, surface charge, and heat-triggered DOX release. Cancer cell targeting and DOX delivery was evaluated by FACS, fluorescence imaging, and HPLC. In vivo particle behavior was analyzed by assessing DOX biodistribution with local HT application in tumor-bearing animals.

Results

The absence of PEG in PG₂-CTSL promoted more efficient liposome–cell interactions, resulting in a higher DOX delivery and cancer cell toxicity compared with PEG-CTSL. By exploiting the dual-targeting function of CTSLs, we were able to selectively trigger DOX release in the intracellular compartment by HT. When tested in vivo, local HT promoted an increase in intratumoral DOX levels for all (C)TSLs tested, with DOX enrichment factors ranging from 3 to 14-fold depending on the type of formulation.

Conclusion

Cationic particles showed lower hemocompatibility than their anionic counterparts, which was partially mitigated when PEG was grafted on the liposome surface. DPPG₂-based anionic TSL showed optimal local drug delivery compared to all other formulations tested, demonstrating the potential advantages of using DPPG₂ lipid in designing liposomes for tumor-targeted applications.

Nonspecific Binding-Fundamental Concepts and Consequences for Biosensing Applications

Nature achieves differentiation of specific and nonspecific binding in molecular interactions through precise control of biomolecules in space and time. Artificial systems such as biosensors that rely on distinguishing specific molecular binding events in a sea of nonspecific interactions have struggled to overcome this issue. Despite the numerous technological advancements in biosensor technologies, nonspecific binding has remained a critical bottleneck due to the lack of a fundamental understanding of the phenomenon. To date, the identity, cause, and influence of nonspecific binding remain topics of debate within the scientific community. In this review, we discuss the evolution of the concept of nonspecific binding over the past five decades based upon the thermodynamic, intermolecular, and structural perspectives to provide classification frameworks for biomolecular interactions. Further, we introduce various theoretical models that predict the expected behavior of biosensors in physiologically relevant environments to calculate the theoretical detection limit and to optimize sensor performance. We conclude by discussing existing practical approaches to tackle the nonspecific binding challenge in vitro for biosensing platforms and how we can both address and harness nonspecific interactions for in vivo systems.

From Residues to Added-Value Bacterial Biopolymers as Nanomaterials for Biomedical Applications

Bacterial biopolymers are naturally occurring materials comprising a wide range of molecules with diverse chemical structures that can be produced from renewable sources following the principles of the circular economy. Over the last decades, they have gained substantial interest in the biomedical field as drug nanocarriers, implantable material coatings, and tissue-regeneration scaffolds or membranes due to their inherent biocompatibility, biodegradability into nonhazardous disintegration products, and their mechanical properties, which are similar to those of human tissues. The present review focuses upon three technologically advanced bacterial biopolymers, namely, bacterial cellulose (BC), polyhydroxyalkanoates (PHA), and γ-polyglutamic acid (PGA), as models of different carbon-backbone structures (polysaccharides, polyesters, and polyamides) produced by bacteria that are suitable for biomedical applications in nanoscale systems. This selection models evidence of the wide versatility of microorganisms to generate biopolymers by diverse metabolic strategies. We highlight the suitability for applied sustainable bioprocesses for the production of BC, PHA, and PGA based on renewable carbon sources and the singularity of each process driven by bacterial machinery. The inherent properties of each polymer can be fine-tuned by means of chemical and biotechnological approaches, such as metabolic engineering and peptide functionalization, to further expand their structural diversity and their applicability as nanomaterials in biomedicine.

Drug Delivery to the Bone Microenvironment Mediated by Exosomes: An Axiom or Enigma

The increasing incidence of bone-related disorders is causing a burden on the clinical scenario. Even though bone is one of the tissues that possess tremendous regenerative potential, certain bone anomalies need therapeutic intervention through appropriate delivery of a drug. Among several nanosystems and biologics that offer the potential to contribute towards bone healing, the exosomes from the class of extracellular vesicles are outstanding. Exosomes are extracellular nanovesicles that, apart from the various advantages, are standing out of the crowd for their ability to conduct cellular communication. The internal cargo of the exosomes is leading to its potential use in therapeutics. Exosomes are being unraveled in terms of the mechanism as well as application in targeting various diseases and tissues. Through this review, we have tried to understand and review all that is already established and the gap areas that still exist in utilizing them as drug delivery vehicles targeting the bone. The review highlights the potential of the exosomes towards their contribution to the drug delivery scenario in the bone microenvironment. A comparison of the pros and cons of exosomes with other prevalent drug delivery systems is also done. A section on the patents that have been generated so far from this field is included.