Hyaluronic acid conjugated micelles possessing CD44 targeting potential for gene delivery

Zein-PEG nanoparticles modified with hyaluronic acid for paclitaxel delivery in SKOV3 ovarian cancer cells

Ovarian cancer is a leading gynecological cancer globally. This study aimed to develop hyaluronic acid-modified polyethylene glycol conjugated zein nanoparticles (zein-PEG/HA NPs) to enhance paclitaxel (PTX) cytotoxicity in SKOV3 ovarian cancer cells. Zein-PEG, with its amphiphilic nature, self-assembled into micelles to encapsulate the hydrophobic PTX, while the PEG shell retained micelle stability and hemolytic resistance. PTX@zein-PEG micelles (17.2 ± 0.3 mV) were complexed with negatively charged HA through electrostatic interactions, resulting in PTX@zein-PEG/HA NPs with a negative zeta potential of -15.3 ± 1.1 mV. Cellular uptake of fluorescent zein-PEG/HA NPs was higher than zein-PEG micelles in CD44-overexpressing SKOV3 cells. Additionally, PTX@zein-PEG/HA NPs demonstrated significantly greater cytotoxicity than free PTX and PTX@zein-PEG micelles, with IC50 values reduced by 6.13-fold and 3.58-fold, respectively. PTX@zein-PEG/HA NPs induced the highest expression levels of apoptotic proteins, particularly PARP, in SKOV3 cells compared to PTX@zein-PEG NPs and free PTX. In summary, PTX@zein-PEG/HA NPs demonstrated potential as a delivery system for PTX in ovarian cancer.

Unveiling the potential of ursolic acid modified hyaluronate nanoparticles for combination drug therapy in triple negative breast cancer

Triple negative breast cancer (TNBC) represents the most aggressive and heterogenous disease, and combination therapy holds promising potential. Here, an enzyme-responsive polymeric prodrug with self-assembly properties was synthesized for targeted co-delivery of paclitaxel (PTX) and ursolic acid (UA). Hyaluronic acid (HA) was conjugated with UA, yielding an amphiphilic prodrug with 13.85 mol% UA and a CMC of 32.3 μg/mL. The HA-UA conjugate exhibited ∼14 % and 47 % hydrolysis at pH 7.4 and in tumor cell lysate. HA-UA/PTX NPs exhibited a spherical structure with 173 nm particle size, and 0.15 PDI. The nanoparticles showed high drug loading (11.58 %) and entrapment efficiency (76.87 %) of PTX. Release experiments revealed accelerated drug release (∼78 %) in the presence of hyaluronidase enzyme. Cellular uptake in MDA-MB-231 cells showed enhanced uptake of HA-UA/PTX NPs through CD44 receptor-mediated endocytosis. In vitro, HA-UA/PTX NPs exhibited higher cytotoxicity, apoptosis, and mitochondrial depolarization compared to PTX alone. In vivo, HA-UA/PTX NPs demonstrated improved pharmacokinetic properties, with 2.18, 2.40, and 2.35-fold higher AUC, t1/2, and MRT compared to free PTX. Notably, HA-UA/PTX NPs exhibited superior antitumor efficacy with a 90 % tumor inhibition rate in 4T1 tumor model and low systemic toxicity, showcasing their significant potential as carriers for TNBC combination therapy.

Hydrogel-exosome system in tissue engineering: A promising therapeutic strategy

Characterized by their pivotal roles in cell-to-cell communication, cell proliferation, and immune regulation during tissue repair, exosomes have emerged as a promising avenue for "cell-free therapy" in clinical applications. Hydrogels, possessing commendable biocompatibility, degradability, adjustability, and physical properties akin to biological tissues, have also found extensive utility in tissue engineering and regenerative repair. The synergistic combination of exosomes and hydrogels holds the potential not only to enhance the efficiency of exosomes but also to collaboratively advance the tissue repair process. This review has summarized the advancements made over the past decade in the research of hydrogel-exosome systems for regenerating various tissues including skin, bone, cartilage, nerves and tendons, with a focus on the methods for encapsulating and releasing exosomes within the hydrogels. It has also critically examined the gaps and limitations in current research, whilst proposed future directions and potential applications of this innovative approach.

Surface Engineering of Natural Killer Cells with CD44-targeting Ligands for Augmented Cancer Immunotherapy

Adoptive immunotherapy utilizing natural killer (NK) cells has demonstrated remarkable efficacy in treating hematologic malignancies. However, its clinical intervention for solid tumors is hindered by the limited expression of tumor-specific antigens. Herein, lipid-PEG conjugated hyaluronic acid (HA) materials (HA-PEG-Lipid) for the simple ex-vivo surface coating of NK cells is developed for 1) lipid-mediated cellular membrane anchoring via hydrophobic interaction and thereby 2) sufficient presentation of the CD44 ligand (i.e., HA) onto NK cells for cancer targeting, without the need for genetic manipulation. Membrane-engineered NK cells can selectively recognize CD44-overexpressing cancer cells through HA-CD44 affinity and subsequently induce in situ activation of NK cells for cancer elimination. Therefore, the surface-engineered NK cells using HA-PEG-Lipid (HANK cells) establish an immune synapse with CD44-overexpressing MIA PaCa-2 pancreatic cancer cells, triggering the "recognition-activation" mechanism, and ultimately eliminating cancer cells. Moreover, in mouse xenograft tumor models, administrated HANK cells demonstrate significant infiltration into solid tumors, resulting in tumor apoptosis/necrosis and effective suppression of tumor progression and metastasis, as compared to NK cells and gemcitabine. Taken together, the HA-PEG-Lipid biomaterials expedite the treatment of solid tumors by facilitating a sequential recognition-activation mechanism of surface-engineered HANK cells, suggesting a promising approach for NK cell-mediated immunotherapy.

Hyaluronic acid modified nanocarriers for aerosolized delivery of verteporfin in the treatment of acute lung injury

Verteporfin (VER), a photosensitizer used in macular degeneration therapy, has shown promise in controlling macrophage polarization and alleviating inflammation in acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). However, its hydrophobicity, limited bioavailability, and side effects hinder its therapeutic potential. In this study, we aimed to enhance the therapeutic potential of VER through pulmonary nebulized drug delivery for ALI/ARDS treatment. We combined hydrophilic hyaluronic acid (HA) with an oil-in-water system containing a poly(lactic acid-co-glycolic acid) (PLGA) copolymer of VER to synthesize HA@PLGA-VER (PHV) nanoparticles with favorable surface characteristics to improve the bioavailability and targeting ability of VER. PHV possesses suitable electrical properties, a narrow size distribution (approximately 200 nm), and favorable stability. In vitro and in vivo studies demonstrated the excellent biocompatibility, safety, and anti-inflammatory responses of the PHV by suppressing M1 macrophage polarization while inducing M2 polarization. The in vivo experiments indicated that the treatment with aerosolized nano-VER (PHV) allowed more drugs to accumulate and penetrate into the lungs, improved the pulmonary function and attenuated lung injury, and mortality of ALI mice, achieving improved therapeutic outcomes. These findings highlight the potential of PHV as a promising delivery system via nebulization for enhancing the therapeutic effects of VER in ALI/ARDS.

Novel polyurethane-based ionene nanoparticles electrostatically stabilized with hyaluronic acid for effective gene therapy

Gene therapy is considered to be a valuable strategy for effective cancer treatment. However, the development of effective delivery systems that can specifically deliver gene materials, such as siRNA to tumor tissues plays a critical role in cancer therapy. In the present study, we have developed a novel complex that is based on an electrostatic interaction between cationic polyurethane ionene (CPUI) nanoparticles and an anti-signal transducer and activator of transcription 3 (STAT3) siRNA. For active targeting, hyaluronic acid (HA) was used to coat the complexes, which significantly reduced the cytotoxicity of the blank nanocarriers while demonstrating high transport efficiency of the siRNA via the CD44-mediated endocytosis pathway in MCF-7 breast cancer cells. The targeted nanocarriers (HA/CPUI/siRNA) showed significantly higher cellular internalization in flow cytometry and confocal microscopy compared with the non-targeted system (CPUI/siRNA). In addition, the incorporation of HA on the surface of the complexes resulted in significantly greater suppression of the STAT3 gene compared to the corresponding non-targeted formulation. Whole-body fluorescence images showed more significant tumor accumulation of the targeted nanocarriers in 4T1 breast tumor-bearing mice. Therefore, HA/CPUI/siRNA nanocarriers are an interesting option for the siRNA-targeted treatment of breast cancer cells.

A detailed insight of the tumor targeting using nanocarrier drug delivery system

Human struggle against the deadly disease conditions is continued since ages. The contribution of science and technology in fighting against these diseases cannot be ignored exclusively due to the invention of novel procedure and products, extending their size ranges from micro to nano. Recently nanotechnology has been gaining more consideration for its ability to diagnose and treat different cancers. Different nanoparticles have been used to evade the issues related with conservative anticancer delivery systems, including their nonspecificity, adverse effects and burst release. These nanocarriers including, solid lipid nanoparticles (SLNs), liposomes, nano lipid carriers (NLCs), nano micelles, nanocomposites, polymeric and magnetic nanocarriers, have brought revolutions in antitumor drug delivery. Nanocarriers improved the therapeutic efficacy of anticancer drugs with better accumulation at the specific site with sustained release, improved bioavailability and apoptosis of the cancer cells while bypassing the normal cells. In this review, the cancer targeting techniques and surface modification on nanoparticles are discussed briefly with possible challenges and opportunities. It can be concluded that understanding the role of nanomedicine in tumor treatment is significant, and therefore, the modern progressions in this arena is essential to be considered for a prosperous today and an affluent future of tumor patients.

Tumor-Associated Macrophages Regulating a Polymer Nanoplatform for Synergistic Treatment of Breast Tumors

Tumor-associated macrophages (TAMs) play a critical role in tumor progression and metastasis. Modulation of TAM polarization is one of the most effective strategies to change the immunosuppressive tumor microenvironment (TME). In this study, organic polymer nanoparticles (CPHT) were prepared using hyaluronic acid (HA)-conjugated disulfide-bonded polyethylene imide (PEIS) as a carrier through a self-assembly strategy. These nanoparticles were modified by transferrin (Tf) and loaded with chlorin e6 (Ce6). The results showed that CPHT had good dispersion with a particle size of about 30 nm. CPHT gradually disintegrated under the exposure with a high concentration of glutathione (GSH) in tumor cells, proving the possibility for the controlled release of Ce6 and photodynamic therapy. An in vitro test showed that the uptake of CPHT in tumor cells was mediated by both HA and Tf, indicating the active tumor-targeting capacity of CPHT. CPHT significantly downregulated the ratio of CD206/CD86 and triggered the upregulation of immune factors such as TNF-α and iNOS, suggesting the repolarization of TAMs. We also found that CPHT effectively induced ferroptosis in tumor cells through lipid peroxide accumulation, GSH depletion, and downregulation of lipid peroxidase (GPX4) expression. Animal experiments confirmed that CPHT not only effectively inhibited the growth of tumors in situ but also significantly decelerated the growth of the distal tumor. Elevated levels of CD86 and IFN-γ and decreased expression of CD206 were observed at the tumor sites post CPHT treatment. These results confirmed the value of CPHT as a multifunctional nanoplatform that can tune the TME and provide new hope for tumor treatment.

Polymeric-Micelle-Based Delivery Systems for Nucleic Acids

Nucleic acids can modulate gene expression specifically. They are increasingly being utilized and show huge potential for the prevention or treatment of various diseases. However, the clinical translation of nucleic acids faces many challenges due to their rapid clearance after administration, low stability in physiological fluids and limited cellular uptake, which is associated with an inability to reach the intracellular target site and poor efficacy. For many years, tremendous efforts have been made to design appropriate delivery systems that enable the safe and effective delivery of nucleic acids at the target site to achieve high therapeutic outcomes. Among the different delivery platforms investigated, polymeric micelles have emerged as suitable delivery vehicles due to the versatility of their structures and the possibility to tailor their composition for overcoming extracellular and intracellular barriers, thus enhancing therapeutic efficacy. Many strategies, such as the addition of stimuli-sensitive groups or specific ligands, can be used to facilitate the delivery of various nucleic acids and improve targeting and accumulation at the site of action while protecting nucleic acids from degradation and promoting their cellular uptake. Furthermore, polymeric micelles can be used to deliver both chemotherapeutic drugs and nucleic acid therapeutics simultaneously to achieve synergistic combination treatment. This review focuses on the design approaches and current developments in polymeric micelles for the delivery of nucleic acids. The different preparation methods and characteristic features of polymeric micelles are covered. The current state of the art of polymeric micelles as carriers for nucleic acids is discussed while highlighting the delivery challenges of nucleic acids and how to overcome them and how to improve the safety and efficacy of nucleic acids after local or systemic administration.

CD44-Targeted Lipid Polymer Hybrid Nanoparticles Enhance Anti-Breast Cancer Effect of Cordyceps militaris Extracts

This study aimed to improve the anticancer effect of Cordyceps militaris herbal extract (CME) on breast cancer cells with hyaluronic acid (HYA) surface-decorated lipid polymer hybrid nanoparticles (LPNPs) and evaluate the applicability of a synthesized poly(glycerol adipate) (PGA) polymer for LPNP preparation. Firstly, cholesterol- and vitamin E-grafted PGA polymers (PGA-CH and PGA-VE, respectively) were fabricated, with and without maleimide-ended polyethylene glycol. Subsequently, CME, which contained an active cordycepin equaling 9.89% of its weight, was encapsulated in the LPNPs. The results revealed that the synthesized polymers could be used to prepare CME-loaded LPNPs. The LPNP formulations containing Mal-PEG were decorated with cysteine-grafted HYA via thiol-maleimide reactions. The HYA-decorated PGA-based LPNPs substantially enhanced the anticancer effect of CME against MDA-MB-231 and MCF-7 breast cancer cells by enhancing cellular uptake through CD44 receptor-mediated endocytosis. This study demonstrated the successful targeted delivery of CME to the CD44 receptors of tumor cells by HYA-conjugated PGA-based LPNPs and the new application of synthesized PGA-CH- and PGA-VE-based polymers in LPNP preparation. The developed LPNPs showed promising potential for the targeted delivery of herbal extracts for cancer treatment and clear potential for translation in in vivo experiments.

Functionalization of hyaluronic acid for development of self-healing hydrogels for biomedical applications: A review

Materials that are capable of undergoing self-repair following any physical damage or rupture due to external stimuli are identified as self-healing materials. Such materials are engineered by crosslinking the polymer backbone chains typically through reversible linkages. These reversible linkages include imines, metal-ligand coordination, polyelectrolyte interaction, disulfide, etc. These bonds are reversibly responsive to changes in various stimuli. Newer self-healing materials are now being developed in the field of biomedicine. Chitosan, cellulose, starch etc. are a few examples of polysaccharides that are generally used to synthesize such materials. Hyaluronic acid has been a very recent addition to the list of polysaccharides that are being investigated for construction of self-healing materials. It is non-toxic, non-immunogenic, has good gelation property and good injectability. Hyaluronic acid based self-healing materials are particularly employed for targeted drug delivery, protein and cell delivery, electronics, biosensors and many such biomedical applications. This review critically focuses on the functionalization of hyaluronic acid to fabricate self-healing hydrogels for biomedical applications. It also explores and sums up the mechanical data as well as self-healing efficiency of the hydrogels across wide range of interactions as discussed in the review below.

Combinatorial synthesis of a hyaluronan based polysaccharide library for enhanced CD44 binding

Hyaluronan (HA) plays important roles in a wide range of biological events. The principal receptor of HA in the human body is the Cluster of Differentiation 44 (CD44). To enhance the binding between HA and CD44, a new approach was designed to take advantage of the four-component Ugi reaction. By modifying the carboxyl group on HA with various amine, aldehyde, and isocyanide moieties through the Ugi reaction, 36 HA like polysaccharides were generated. Two lead compounds were identified with enhanced CD44 binding compared to unmodified HA, which was confirmed by surface plasmon resonance (SPR), cellular studies and an in vivo mouse tumor model. Ski-learn as a machine learning tool was applied to analyze library data and yield predictions with an accuracy over 80 %. In conclusion, modification of HA via the Ugi reaction can be a promising strategy to develop novel binders toward HA receptors such as CD44.

Advancements in Polymeric Nanocarriers to Mediate Targeted Therapy against Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a destructive disease with a poor prognosis, low survival rate and high rate of metastasis. It comprises 15% of total breast cancers and is marked by deficiency of three important receptor expressions, i.e., progesterone, estrogen, and human epidermal growth factor receptors. This absence of receptors is the foremost cause of current TNBC therapy failure, resulting in poor therapeutic response in patients. Polymeric nanoparticles are gaining much popularity for transporting chemotherapeutics, genes, and small-interfering RNAs. Due to their exclusive properties such as great stability, easy surface modification, stimuli-responsive and controlled drug release, ability to condense more than one therapeutic moiety inside, tumor-specific delivery of payload, enhanced permeation and retention effect, present them as ideal nanocarriers for increasing efficacy, bioavailability and reducing the toxicity of therapeutic agents. They can even be used as theragnostic agents for the diagnosis of TNBC along with its treatment. In this review, we discuss the limitations of already existing TNBC therapies and highlight the novel approach to designing and the functionalization of polymeric nanocarriers for the effective treatment of TNBC.

"Willow Branch" DNA Self-Assembly for Cancer Dual-Target and Proliferation Inhibition

DNA nanotechnology is beginning to yield unique advantages in the area of drug delivery. For the dual-targeting and proliferation suppression of cancer cells, a "willow branch" DNA assembly based on rolling circle amplification (RCA) was built. Three single-stranded DNAs, including antibody modified cDNAs, aptamer cDNAs, and simple cDNAs, were employed in the DNA self-assembly, along with the RCA scaffolds (every 63 bases is a repeat unit). "Willow branch" DNA (WB DNA) assembly successfully linked multiple antibodies and aptamers together to achieve dual targeting of cancer cells. Binding of CD44 antibodies and S2.2 aptamers to receptors on the cell membrane inhibits both pathways, β-catenin signaling and nuclear factor-kappa B-specific transcription activity, through feedback regulation. Results demonstrated that WB DNA assembly could effectively exert multivalency clustering cell-surface receptors, modulating signal pathways and inhibiting proliferation. This study proposes a new approach for cancer dual-target and proliferation inhibition by clustering multivalent receptors.

A Multifunctional Non-viral Vector for the Delivery of MTH1-targeted CRISPR/Cas9 System for Non-Small Cell Lung Cancer Therapy

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system adapted from bacteria is a programmable nuclease-based genome editing tool. The long-lasting effect of gene silencing or correction is beneficial in cancer treatment. Considering the need to broaden the practical application of this technology, highly efficient non-viral vectors are urgently required. We prepared a multifunctional non-viral vector that could actively target tumor cells and deliver CRISPR/Cas9 plasmids into nuclei of cancer cells. Protamine sulfate (PS) which contains nuclear localization sequence was utilized to condense plasmid DNA and facilitate nuclei-targeted delivery. Liposome-coated protein/DNA complex avoided the degradation of nuclease in blood circulation. The obtained PS@Lip/pCas9 was further modified with distearoyl phosphoethanolamine-polyethylene glycol-hyaluronic acid (HA) to endow the vector ability to actively target tumor cell. Results suggested that PS@HA-Lip could deliver CRISPR/Cas9 plasmids into nuclei of tumor cells and induce genome editing effect. With the disruption of MTH1 (mutT homolog1) gene, the growth of non-small cell lung cancer was inhibited. Moreover, cell apoptosis in tumor tissue was promoted, and liver metastasis of non-small cell lung cancer (NSCLC) was reduced. Our study has provided a therapeutic strategy targeting MTH1 gene for NSCLC therapy. STATEMENT OF SIGNIFICANCE: CRISPR/Cas9 as a powerful tool for genome editing has drawn much attention. The long-lasting effect possesses unique advantage in cancer treatment. Non-viral vectors have high loading capacity, high safety and low immunogenicity, playing an important role in CRISPR/Cas9 delivery. In our study, a multifunctional non-viral vector for the efficient delivery of CRISPR/Cas9 plasmid was constructed. With the active targeting ligand and nuclei-targeting component, the cargo was efficiently delivered into cell nuclei and exerted genome editing effect. By using this vector, we successfully inhibited the growth and induced the apoptosis of non-small cell lung cancer by disrupting MTH1 expression with good safety. Our work provided an efficient non-vial vector for CRISPR/Cas9 delivery and explored the possibility for cancer treatment.

Appraisal for the Potential of Viral and Nonviral Vectors in Gene Therapy: A Review

Over the past few decades, gene therapy has gained immense importance in medical research as a promising treatment strategy for diseases such as cancer, AIDS, Alzheimer's disease, and many genetic disorders. When a gene needs to be delivered to a target cell inside the human body, it has to pass a large number of barriers through the extracellular and intracellular environment. This is why the delivery of naked genes and nucleic acids is highly unfavorable, and gene delivery requires suitable vectors that can carry the gene cargo to the target site and protect it from biological degradation. To date, medical research has come up with two types of gene delivery vectors, which are viral and nonviral vectors. The ability of viruses to protect transgenes from biological degradation and their capability to efficiently cross cellular barriers have allowed gene therapy research to develop new approaches utilizing viruses and their different genomes as vectors for gene delivery. Although viral vectors are very efficient, science has also come up with numerous nonviral systems based on cationic lipids, cationic polymers, and inorganic particles that provide sustainable gene expression without triggering unwanted inflammatory and immune reactions, and that are considered nontoxic. In this review, we discuss in detail the latest data available on all viral and nonviral vectors used in gene delivery. The mechanisms of viral and nonviral vector-based gene delivery are presented, and the advantages and disadvantages of all types of vectors are also given.

Partial ligand shielding nanoparticles improve pancreatic ductal adenocarcinoma treatment via a multifunctional paradigm for tumor stroma reprogramming

The dense stroma that acts as a physical and biological barrier in the tumor microenvironment (TME) of pancreatic ductal adenocarcinoma (PDAC) leads to the failure of chemotherapeutic drug delivery. Cancer-associated fibroblasts (CAFs) and extracellular matrix (ECM) mainly constitute the refuge for cancer cells in PDAC. Herein, a CAF targeting drug delivery system (TDDS) based on RBC vesicles partial protection (RBC-Fn-NP) was established and investigated for reprogramming stroma, as well as enhancing tumor penetration and antitumor efficacy in PDAC. RBC vesicles were firstly used for partial protection of peptide from external influences. The exposed FnBPA5 peptide showed high affinity with both CAFs and the major components as collagen I and relaxed-fibronectin of ECM. Retinoic acid (RA) could disturb Golgi of CAFs, resulting in the reduction of protein secretion from the headstream. As expected, the strategy of RBC vesicles protected FnBPA5 targeting and RA-induced protein reduction was confirmed to reprogram the dense stroma and improve the penetration of Doxorubicin (Dox) in PDAC. RBC-Fn-NP inhibited tumor growth in both Pan02-orthotopic bearing model and Pan02-subcutaneous mice model. Hence, these partial ligand shielding nanoparticles offer a multifunctional and efficient approach to overcome penetration barriers and enhance the antitumor efficacy of chemotherapy in PDAC. STATEMENT OF SIGNIFICANCE: A partial ligand shielding nanoparticle platform (RBC-Fn-NP), which has the function of an RBC vesicle "shell" and thetargeting properties of a "core" to achieve superior therapeutic effects against PDAC, was established. The targeted ligand was modified on the surface of the nanoparticles instead of the RBC membranes. Three-dimensional PDAC stroma-rich spheroids were established to evaluate the penetration and tumor stroma remodeling. The targeting properties of FnBPA5 peptide, the effect of RA-induced Golgi disruption on the reduction of protein secretion, and the incomplete "camouflage" of the RBC vesicles were confirmed both in vitro and in vivo. As expected, our nanoplatform may provide a promising strategy for remolding dense stroma and enhancing the permeability in PDAC.

Natural and Synthetic Micelles for Delivery of Small Molecule Drugs, Imaging Agents and Nucleic Acids

The poor solubility, lack of targetability, quick renal clearance, and degradability of many therapeutic and imaging agents strongly limit their applications inside the human body. Amphiphilic copolymers having self-assembling properties can form core-shell structures called micelles, a promising nanocarrier for hydrophobic drugs, plasmid DNA, oligonucleotides, small interfering RNAs (siRNAs) and imaging agents. Fabrication of micelles loaded with different pharmaceutical agents provides numerous advantages including therapeutic efficacy, diagnostic sensitivity, and controlled release to the desired tissues. Moreover, due to their smaller particle size (10-100 nm) and modified surfaces with different functional groups (such as ligands) help them to accumulate easily in the target location, enhancing cellular uptake and reducing unwanted side effects. Furthermore, the release of the encapsulated agents may also be triggered from stimuli-sensitive micelles at different physiological conditions or by an external stimulus. In this review article, we discuss the recent advancement in formulating and targeting different natural and synthetic micelles including block copolymer micelles, cationic micelles, and dendrimers-, polysaccharide- and protein-based micelles for the delivery of different therapeutic and diagnostic agents. Finally, their applications, outcomes, and future perspectives have been summarized.

Synthesis of self-assembled hyaluronan based nanoparticles and their applications in targeted imaging and therapy

Hyaluronan (HA) is a polysaccharide consisting of repeating disaccharides of N-acetyl-d-glucosamine and d-glucuronic acid. There are increasing interests in utilizing self-assembled HA nanoparticles (HA-NPs) for targeted imaging and therapy. The principal endogenous receptor of HA, cluster of differentiation 44 (CD44), is overexpressed on many types of tumor cells as well as inflammatory cells in human bodies. Active targeting from HA-CD44 mediated interaction and passive targeting due to the enhanced permeability retention (EPR) effect could lead to selective accumulation of HA-NPs at targeted disease sites. This review focuses on the synthesis strategies of self-assembled HA-NPs, as well as their applications in therapy and biomedical imaging.

Multiple-therapy strategies via polysaccharides-based nano-systems in fighting cancer

Polysaccharide-based biomaterials (e.g., chitosan, dextran, hyaluronic acid, chondroitin sulfate and heparin) have received great attention in healthcare, particularly in drug delivery for tumor therapy. They are naturally abundant and available, outstandingly biodegradable and biocompatible, and they generally have negligible toxicity and low immunogenicity. In addition, they are easily chemically or physically modified. Therefore, PSs-based nanoparticles (NPs) have been extensively investigated for the enhancement of tumor treatment. In this review, we introduce the synthetic pathways of amphiphilic PS derivatives, which allow the constructs to self-assemble into NPs with various structures. We especially offer an overview of the emerging applications of self-assembled PSs-based NPs in tumor chemotherapy, photothermal therapy (PTT), photodynamic therapy (PDT), gene therapy and immunotherapy. We believe that this review can provide criteria for a rational and molecular level-based design of PS-based NPs, and comprehensive insight into the potential of PS-based NPs used in multiple cancer therapies.

Mesoporous silica nanoparticles loaded with fluorescent coumarin-5-fluorouracil conjugates as mitochondrial-targeting theranostic probes for tumor cells

In this study, a nanodrug carrier (mesoporous silica nanoparticle (MSN)-SS-cysteamine hydrochloride (CS)-hyaluronic acid (HA)) for targeted drug delivery was prepared using MSNs, in which HA was used as a targeting ligand and blocking agent to control drug release. Coumarin is a fluorescent molecule that targets mitochondria. Two conjugates (XDS-DJ and 5-FUA-4C-XDS) were synthesized by chemically coupling nitrogen mustard and 5-fluorouracil with coumarin, which was further loaded into MSN-SS-CS-HA nanocarriers. MTT analysis demonstrated that the nanocomposite MSN-SS-CS@5-FUA-4C-XDS/HA displayed stronger cytotoxicity toward HCT-116 cells than HeLa or QSG-7701 cells. Furthermore, MSN-SS-CS@5-FUA-4C-XDS/HA was able to target the mitochondria of HCT-116 cells, causing decreased mitochondrial membrane potential and excessive production of reactive oxygen species. These results indicate that MSN-SS-CS@5-FUA-4C-XDS/HA has the potential to be a nanodrug delivery system for the treatment of colon cancer.

A review of the tortuous path of nonviral gene delivery and recent progress

Gene therapy encompasses the transfer of exogenous genetic materials into the patient's target cells to treat or prevent diseases. Nevertheless, the transfer of genetic material into desired cells is challenging and often requires specialized tools or delivery systems. For the past 40 years, scientists are mainly pursuing various viruses as gene delivery vectors, and the overall progress has been slow and far from the expectation. As an alternative, nonviral vectors have gained substantial attention due to their several advantages, including superior safety profile, enhanced payload capacity, and stealth abilities. Since nonviral vectors encounter multiple extra- and intra-cellular barriers limiting the transfer of genetic payload into the target cell nucleus, we have discussed these barriers in detail for this review. A direct approach, utilizing physical methods like electroporation, sonoporation, gene gun, eliminate the requirement for a specific carrier for gene delivery. In contrast, chemical methods of gene transfer exploit natural or synthetic compounds as carriers to increase cellular targeting and gene therapy effectiveness. We have also emphasized the recent advancements aimed at enhancing the current nonviral approaches. Therefore, in this review, we have focused on discussing the current evolving state of nonviral gene delivery systems and their future perspectives.

CD44-Targeted and Enzyme-Responsive Photo-Cross-Linked Nanogels with Enhanced Stability for In Vivo Protein Delivery

One of the biggest challenges of the protein delivery system is to realize stable and high protein encapsulation efficiency in blood circulation and rapid release of protein in the targeted tumor cells. To overcome these hurdles, we fabricated enzyme-responsive photo-cross-linked nanogels (EPNGs) through UV-triggered chemical cross-linking of cinnamyloxy groups in the side chain of PEGylation hyaluronic acid (HA) for CD44-targeted transport of cytochrome c (CC). The EPNGs showed high loading efficiency and excellent stability in different biological media. Notably, CC leakage effectively suppressed under physiological conditions but accelerated release in the presence of hyaluronidase, an overexpressed enzyme in tumor cells. Moreover, thiazolylblue tetrazolium bromide (MTT) results indicated that the vacant EPNGs showed excellent nontoxicity, while CC-loaded EPNGs exhibited higher killing efficiency to CD44-positive A549 cells than to CD44-negative HepG2 cells and free CC. Confocal images confirmed that CC-loaded EPNGs could effectively be internalized by CD44-mediated endocytosis pathway and rapidly escape from the endo/lysosomal compartment. Human lung tumor-bearing mice imaging assays further revealed that CC-loaded EPNGs actively target tumor locations. Remarkably, CC-loaded EPNGs also exhibited enhanced antitumor activity with negligible systemic toxicity. These results implied that these EPNGs have appeared as stable and promising nanocarriers for tumor-targeting protein delivery.

Hyaluronan as a Prominent Biomolecule with Numerous Applications in Medicine

Hyaluronan (HA) is a natural glycosaminoglycan present in many tissues of all vertebrates. HA has various biological functions, which are dependent on its molar mass. High-molar-mass HA has anti-angiogenic, immunosuppressive and anti-inflammatory properties, while low-molar-mass HA has opposite effects. HA has also antioxidative properties, however on the other hand it can be readily degraded by reactive oxygen species. For many years it has been used in treatment of osteoarthritis, cosmetics and in ophthalmology. In the last years there has been a growing interest of HA to also be applied in other fields of medicine such as skin wound healing, tissue engineering, dentistry and gene delivery. In this review we summarize information on modes of HA administration, properties and effects of HA in various fields of medicine including recent progress in the investigation of HA.

Biopolymer-based Carriers for DNA Vaccine Design

Over the last 30 years, genetically engineered DNA has been tested as novel vaccination strategy against various diseases, including human immunodeficiency virus (HIV), hepatitis B, several parasites, and cancers. However, the clinical breakthrough of the technique is confined by the low transfection efficacy and immunogenicity of the employed vaccines. Therefore, carrier materials were designed to prevent the rapid degradation and systemic clearance of DNA in the body. In this context, biopolymers are a particularly promising DNA vaccine carrier platform due to their beneficial biochemical and physical characteristics, including biocompatibility, stability, and low toxicity. This article reviews the applications, fabrication, and modification of biopolymers as carrier medium for genetic vaccines.

Understanding nanoparticle endocytosis to improve targeting strategies in nanomedicine

Nanoparticles (NPs) have attracted considerable attention in various fields, such as cosmetics, the food industry, material design, and nanomedicine. In particular, the fast-moving field of nanomedicine takes advantage of features of NPs for the detection and treatment of different types of cancer, fibrosis, inflammation, arthritis as well as neurodegenerative and gastrointestinal diseases. To this end, a detailed understanding of the NP uptake mechanisms by cells and intracellular localization is essential for safe and efficient therapeutic applications. In the first part of this review, we describe the several endocytic pathways involved in the internalization of NPs and we discuss the impact of the physicochemical properties of NPs on this process. In addition, the potential challenges of using various inhibitors, endocytic markers and genetic approaches to study endocytosis are addressed along with the principal (semi) quantification methods of NP uptake. The second part focuses on synthetic and bio-inspired substances, which can stimulate or decrease the cellular uptake of NPs. This approach could be interesting in nanomedicine where a high accumulation of drugs in the target cells is desirable and clearance by immune cells is to be avoided. This review contributes to an improved understanding of NP endocytic pathways and reveals potential substances, which can be used in nanomedicine to improve NP delivery.

Dual-Targeted Hyaluronic Acid/Albumin Micelle-Like Nanoparticles for the Vectorization of Doxorubicin

Drug targeting of tumor cells is one of the great challenges in cancer therapy; nanoparticles based on natural polymers represent valuable tools to achieve this aim. The ability to respond to environmental signals from the pathological site (e.g., altered redox potential), together with the specific interaction with membrane receptors overexpressed on cancer cells membrane (e.g., CD44 receptors), represent the main features of actively targeted nanoparticles. In this work, redox-responsive micelle-like nanoparticles were prepared by self-assembling of a hyaluronic acid–human serum albumin conjugate containing cystamine moieties acting as a functional spacer. The conjugation procedure consisted of a reductive amination step of hyaluronic acid followed by condensation with albumin. After self-assembling, nanoparticles with a mean size of 70 nm and able to be destabilized in reducing media were obtained. Doxorubicin-loaded nanoparticles modulated drug release rate in response to different redox conditions. Finally, the viability and uptake experiments on healthy (BALB-3T3) and metastatic cancer (MDA-MB-231) cells proved the potential applicability of the proposed system as a drug vector in cancer therapy.

Drug delivery systems based on CD44-targeted glycosaminoglycans for cancer therapy

The polysaccharide-based biomaterials hyaluronic acid (HA) and chondroitin sulfate (CS) have aroused great interest for use in drug delivery systems for tumor therapy, as they have outstanding biocompatibility and great targeting ability for cluster determinant 44 (CD44). In addition, modified HA and CS can self-assemble into micelles or micellar nanoparticles (NPs) for targeted drug delivery. This review discusses the formation of HA- and CS-based NPs, and various types of CS-based NPs including CS-drug conjugates, CS-polymer NPs, CS-small molecule NPs, polyelectrolyte nanocomplexes (PECs), CS-metal NPs, and nanogels. We then focus on the applications of HA- and CS-based NPs in tumor chemotherapy, gene therapy, photothermal therapy (PTT), photodynamic therapy (PDT), sonodynamic therapy (SDT), and immunotherapy. Finally, this review is expected to provide guidelines for the development of various HA- and CS-based NPs used in multiple cancer therapies.

Fabrication of Injectable, Porous Hyaluronic Acid Hydrogel Based on an In-Situ Bubble-Forming Hydrogel Entrapment Process

Injectable hydrogels have been widely applied in the field of regenerative medicine. However, current techniques for injectable hydrogels are facing a challenge when trying to generate a biomimetic, porous architecture that is well-acknowledged to facilitate cell behaviors. In this study, an injectable, interconnected, porous hyaluronic acid (HA) hydrogel based on an in-situ bubble self-generation and entrapment process was developed. Through an amide reaction between HA and cystamine dihydrochloride activated by EDC/NHS, CO2 bubbles were generated and were subsequently entrapped inside the substrate due to a rapid gelation-induced retention effect. HA hydrogels with different molecular weights and concentrations were prepared and the effects of the hydrogel precursor solution's concentration and viscosity on the properties of hydrogels were investigated. The results showed that HA10-10 (10 wt.%, MW 100,000 Da) and HA20-2.5 (2.5 wt.%, MW 200,000 Da) exhibited desirable gelation and obvious porous structure. Moreover, HA10-10 represented a high elastic modulus (32 kPa). According to the further in vitro and in vivo studies, all the hydrogels prepared in this study show favorable biocompatibility for desirable cell behaviors and mild host response. Overall, such an in-situ hydrogel with a self-forming bubble and entrapment strategy is believed to provide a robust and versatile platform to engineer injectable hydrogels for a variety of applications in tissue engineering, regenerative medicine, and personalized therapeutics.

Development of stimuli-responsive intelligent polymer micelles for the delivery of doxorubicin

Doxorubicin is still used as a first-line drug in current therapeutics for numerous types of malignant tumours (including lymphoma, transplantable leukaemia and solid tumour). Nevertheless, to overcome the serious side effects like cardiotoxicity and myelosuppression caused by effective doses of doxorubicin remains as a world-class puzzle. In recent years, the usage of biocompatible polymeric nanomaterials to form an intelligently sensitive carrier for the targeted release in tumour microenvironment has attracted wide attention. These different intelligent polymeric micelles (PMs) could change the pharmacokinetics process of drugs or respond in the special microenvironment of tumour site to maximise the efficacy and reduce the toxicity of doxorubicin in other tissues and organs. Several intelligent PMs have already been in the clinical research stage and planned for market. Therefore, related research remains active, and the latest nanotechnology approaches for doxorubicin delivery are always in the spotlight. Centring on the model drugs doxorubicin, this review summarised the mechanisms of PMs, classified the polymers used in the application of doxorubicin delivery and discussed some interesting and imaginative smart PMs in recent years.

Biodegradable Polymers for Gene-Delivery Applications

Gene-based therapies have emerged as a new modality for combating a myriad of currently incurable diseases. However, the fragile nature of gene therapeutics has significantly hampered their biomedical applications. Correspondingly, the development of gene-delivery vectors is of critical importance for gene-based therapies. To date, a variety of gene-delivery vectors have been created and utilized for gene delivery. In general, they can be categorized into viral- and non-viral vectors. Due to safety issues associated with viral vectors, non-viral vectors have recently attracted much more research focus. Of these non-viral vectors, polymeric vectors, which have been preferred due to their low immunogenicity, ease of production, controlled chemical composition and high chemical versatility, have constituted an ideal alternative to viral vectors. In particular, biodegradable polymers, which possess advantageous biocompatibility and biosafety, have been considered to have great potential in clinical applications. In this context, the aim of this review is to introduce the recent development and progress of biodegradable polymers for gene delivery applications, especially for their chemical structure design, gene delivery capacity and additional biological functions. Accordingly, we first define and categorize biodegradable polymers, followed by describing their corresponding degradation mechanisms. Various types of biodegradable polymers resulting from natural and synthetic polymers will be introduced and their applications in gene delivery will be examined. Finally, a future perspective regarding the development of biodegradable polymer vectors will be given.

Recent advantage of hyaluronic acid for anti-cancer application: a review of "3S" transition approach

In recent years, nano drug delivery system has been widely concerned because of its good therapeutic effect. However, the process from blood circulation to cancer cell release of nanodrugs will be eliminated by the human body's own defense trap, thus reducing the therapeutic effect. In recent years, a "3S" transition concept, including stability transition, surface transition and size transition, was proposed to overcome the barriers in delivery process. Hyaluronic (HA) acid has been widely used in delivery of anticancer drugs due to its excellent biocompatibility, biodegradability and specific targeting to cancer cells. In this paper, the strategies and methods of HA-based nanomaterials using "3S" theory are reviewed. The applications and effects of "3S" modified nanomaterials in various fields are also introduced.

Ligand targeting and peptide functionalized polymers as non-viral carriers for gene therapy

Ligand targeting and peptide functionalized polymers serve as gene carriers for efficient gene delivery.

A thermo-sensitive injectable hydroxypropyl chitin hydrogel for sustained salmon calcitonin release with enhanced osteogenesis and hypocalcemic effects

Pharmacotherapy towards hypercalcemia treatment mainly caused by osteoporosis and bone tumor is an effective method to regulate in vivo calcium equilibrium. As a clinical therapeutic peptide, salmon calcitonin (sCT) is considered as a quick-acting medicine but it is limited by the short half-life. To address this challenge, we designed an injectable thermo-sensitive hydrogel based on hydroxypropyl chitin (HPCH) and incorporated the complex of sCT and hyaluronic acid (HA) (sCT-HA) with high association efficiency up to 96.84 ± 7.25%. This composite hydrogel showed a tunable biodegradable property. In vitro sCT release profiles revealed that this hydrogel can achieve long-term sustained sCT release (28 days) with considerable structure stability. The cellular study illustrated outstanding compatibility and osteoconductive potential of this multi-component hydrogel according to the higher ALP activity (2.10-fold), calcium expression (2.30-fold) and extracellular calcium deposition (1.10-fold) compared to that of the sCT group. In vivo sCT release confirmed that this hydrogel system realized sustained sCT release and a continuous hypocalcemic effect for as long as 28 days, and there were no inflammation and immune responses according to the histological evaluations (H&E and IgG staining). These findings demonstrate that this osteoconductive hydrogel system can provide a promising method for therapy of bone related disease.

Hyaluronic acid-coated pH sensitive poly (β-amino ester) nanoparticles for co-delivery of embelin and TRAIL plasmid for triple negative breast cancer treatment

Triple negative breast cancer (TNBC) still lacks an effective targeted treatment. In this study, hyaluronic acid (HA)-mediated tumor targeting and pH-sensitive amphiphilic polymeric nanoparticles were designed and prepared to co-deliver the anticancer drug embelin (EMB) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) plasmid (pTRAIL) (EMB/TRAIL-HA/PBAE-PEI) for synergistic anti-breast cancer efficacy. These pH-sensitive amphiphilic polymeric nanoparticles were formed using the amphiphilic polymers polyethyleneimine (PEI)-poly[(1,6-hexanediol)-diacrylate-β-5-hydroxyamylamine] (PBAE), which was synthesized via Michael addition polymerization. Taking advantage of the specific binding between HA and CD44, which is highly expressed in MDA-MB-231 TNBC cells, the HA-coated nanoparticles increased drug uptake in MDA-MB-231 TNBC cells compared with MCF-7 non-TNBC cells with lower CD44 expression. Moreover, EMB/TRAIL-HA/PBAE-PEI exhibited enhanced cytotoxic and pro-apoptotic effects against MDA-MB-231 cells compared with free EMB and EMB- or pTRAIL-loaded nanoparticles via activation of caspase 3/7, an increase in reactive oxygen species levels, and inhibition of the expressions of apoptosis-related proteins. These results demonstrated that EMB/TRAIL-HA/PBAE-PEI exerted enhanced cytotoxic and pro-apoptotic effects against MDA-MB-231 cells and showed great potential for TNBC treatment.

Polymeric nanoparticles as carrier for targeted and controlled delivery of anticancer agents

In recent decades, many novel methods by using nanoparticles (NPs) have been investigated for diagnosis, drug delivery and treatment of cancer. Accordingly, the potential of NPs as carriers is very significant for the delivery of anticancer drugs, because cancer treatment with NPs has led to the improvement of some of the drug delivery limitations such as low blood circulation time and bioavailability, lack of water solubility, drug adverse effect. In addition, the NPs protect drugs against enzymatic degradation and can lead to the targeted and/or controlled release of the drug. The present review focuses on the potential of NPs that can help the targeted and/or controlled delivery of anticancer agents for cancer therapy.