F3-targeted cisplatin-hydrogel nanoparticles as an effective therapeutic that targets both murine and human ovarian tumor endothelial cells in vivo

Incorporation of immunotherapies and nanomedicine to better normalize angiogenesis-based cancer treatment

Neoadjuvant targeting of tumor angiogenesis has been developed and approved for the treatment of malignant tumors. However, vascular disruption leads to tumor hypoxia, which exacerbates the treatment process and causes drug resistance. In addition, successful delivery of therapeutic agents and efficacy of radiotherapy require normal vascular networks and sufficient oxygen, which complete tumor vasculopathy hinders their efficacy. In view of this controversy, an optimal dose of FDA-approved anti-angiogenic agents and combination with other therapies, such as immunotherapy and the use of nanocarrier-mediated targeted therapy, could improve therapeutic regimens, reduce the need for administration of high doses of chemotherapeutic agents and subsequently reduce side effects. Here, we review the mechanism of anti-angiogenic agents, highlight the challenges of existing therapies, and present how the combination of immunotherapies and nanomedicine could improve angiogenesis-based tumor treatment.

Applications of self-assembled peptide hydrogels in anti-tumor therapy

Peptides are a class of active substances composed of a variety of amino acids with special physiological functions. The rational design of peptide sequences at the molecular level enables their folding into diverse secondary structures. This property has garnered significant attention in the biomedical sphere owing to their favorable biocompatibility, adaptable mechanical traits, and exceptional loading capabilities. Concurrently with advancements in modern medicine, the diagnosis and treatment of tumors have increasingly embraced targeted and personalized approaches. This review explores recent applications of self-assembled peptides derived from natural amino acids in chemical therapy, immunotherapy, and other adjunctive treatments. We highlighted the utilization of peptide hydrogels as delivery systems for chemotherapeutic drugs and other bioactive molecules and then discussed the challenges and prospects for their future application.

Advances in peptide-based drug delivery systems

Drug delivery systems (DDSs) are designed to deliver drugs to their specific targets to minimize their toxic effects and improve their susceptibility to clearance during targeted transport. Peptides have high affinity, low immunogenicity, simple amino acid composition, and adjustable molecular size; therefore, most peptides can be coupled to drugs via linkers to form peptide-drug conjugates (PDCs) and act as active pro-drugs. PDCs are widely thought to be promising DDSs, given their ability to improve drug bio-compatibility and physiological stability. Peptide-based DDSs are often used to deliver therapeutic substances such as anti-cancer drugs and nucleic acid-based drugs, which not only slow the degradation rate of drugs in vivo but also ensure the drug concentration at the targeted site and prolong the half-life of drugs in vivo. This article provides an profile of the advancements and future development in functional peptide-based DDSs both domestically and internationally in recent years, in the expectation of achieving targeted drug delivery incorporating functional peptides and taking full advantage of synergistic effects.

Emerging nanotechnological approaches to regulating tumor vasculature for cancer therapy

Abnormal angiogenesis stands for one of the most striking manifestations of malignant tumor. The pathologically and structurally abnormal tumor vasculature facilitates a hostile tumor microenvironment, providing an ideal refuge exclusively for cancer cells. The emergence of vascular regulation drugs has introduced a distinctive class of therapeutics capable of influencing nutrition supply and drug delivery efficacy without the need to penetrate a series of physical barriers to reach tumor cells. Nanomedicines have been further developed for more precise regulation of tumor vasculature with the capacity of co-delivering multiple active pharmaceutical ingredients, which overall reduces the systemic toxicity and boosts the therapeutic efficacy of free drugs. Additionally, precise structure design enables the integration of specific functional motifs, such as surface-targeting ligands, droppable shells, degradable framework, or stimuli-responsive components into nanomedicines, which can improve tissue-specific accumulation, enhance tissue penetration, and realize the controlled and stimulus-triggered release of the loaded cargo. This review describes the morphological and functional characteristics of tumor blood vessels and summarizes the pivotal molecular targets commonly used in nanomedicine design, and then highlights the recent cutting-edge advancements utilizing nanotechnologies for precise regulation of tumor vasculature. Finally, the challenges and future directions of this field are discussed.

Nucleolin‑based targeting strategies in cancer treatment: Focus on cancer immunotherapy (Review)

The benefits of treating several types of cancers using immunotherapy have recently been established. The overexpression of nucleolin (NCL) in a number of types of cancer provides an attractive antigen target for the development of novel anticancer immunotherapeutic treatments. NCL is a multifunctional protein abundantly distributed in the nucleus, cytoplasm and cell membrane. It influences carcinogenesis, and the proliferation, survival and metastasis of cancer cells, leading to cancer progression. Additionally, the meta‑analysis of total and cytoplasmic NCL overexpression indicates a poor prognosis of patients with breast cancer. The AS1411 aptamers currently appear to have therapeutic action in the phase II clinical trial. The authors' research group has recently explored the anticancer function of NCL through the activation of T cells by dendritic cell‑based immunotherapy. The present review describes and discusses the mechanisms through which the multiple functions of NCL can participate in the progression of cancer. In addition, the studies that define the utility of NCL‑dependent anticancer therapies are summarized, with specific focus being paid to cancer immunotherapeutic approaches.

Natural Polymeric Nanobiocomposites for Anti-Cancer Drug Delivery Therapeutics: A Recent Update

Cancer is one of the most common lethal diseases and the leading cause of mortality worldwide. Effective cancer treatment is a global problem, and subsequent advancements in nanomedicine are useful as substitute management for anti-cancer agents. Nanotechnology, which is gaining popularity, enables fast-expanding delivery methods in science for curing diseases in a site-specific approach, utilizing natural bioactive substances because several studies have established that natural plant-based bioactive compounds can improve the effectiveness of chemotherapy. Bioactive, in combination with nanotechnology, is an exceptionally alluring and recent development in the fight against cancer. Along with their nutritional advantages, natural bioactive chemicals may be used as chemotherapeutic medications to manage cancer. Alginate, starch, xanthan gum, pectin, guar gum, hyaluronic acid, gelatin, albumin, collagen, cellulose, chitosan, and other biopolymers have been employed successfully in the delivery of medicinal products to particular sites. Due to their biodegradability, natural polymeric nanobiocomposites have garnered much interest in developing novel anti-cancer drug delivery methods. There are several techniques to create biopolymer-based nanoparticle systems. However, these systems must be created in an affordable and environmentally sustainable way to be more readily available, selective, and less hazardous to increase treatment effectiveness. Thus, an extensive comprehension of the various facets and recent developments in natural polymeric nanobiocomposites utilized to deliver anti-cancer drugs is imperative. The present article provides an overview of the latest research and developments in natural polymeric nanobiocomposites, particularly emphasizing their applications in the controlled and targeted delivery of anti-cancer drugs.

Combat Against Gynecological Cancers with Blood Vessels as Entry Point: Anti-Angiogenic Drugs, Clinical Trials and Pre-Clinical Nano-Delivery Platforms

Angiogenesis is an essential mechanism for the progression of gynecological cancers. Although approved anti-angiogenic drugs have demonstrated clinical efficacy in treating gynecological cancers, the full potential of therapeutic strategies based on tumor blood vessels has not yet been realized. This review summarizes the latest angiogenesis mechanisms involved in the progression of gynecological cancers and discusses the current clinical practice of approved anti-angiogenic drugs and related clinical trials. Given the close relationship between gynecological cancers and blood vessels, we highlight more delicate strategies for regulating tumor vessels, including wise drug combinations and smart nano-delivery platforms to achieve highly efficient drug delivery and overall vessel microenvironment regulation. We also address current challenges and future opportunities in this field. We aim to generate interest in therapeutic strategies that target blood vessels as a key entry point and offer new potential and inspiration for combating gynecological cancers.

Nanomedicine Penetration to Tumor: Challenges, and Advanced Strategies to Tackle This Issue

Nanomedicine has been under investigation for several years to improve the efficiency of chemotherapeutics, having minimal pharmacological effects clinically. Ineffective tumor penetration is mediated by tumor environments, including limited vascular system, rising cancer cells, higher interstitial pressure, and extra-cellular matrix, among other things. Thus far, numerous methods to increase nanomedicine access to tumors have been described, including the manipulation of tumor micro-environments and the improvement of nanomedicine characteristics; however, such outdated approaches still have shortcomings. Multi-functional convertible nanocarriers have recently been developed as an innovative nanomedicine generation with excellent tumor infiltration abilities, such as tumor-penetrating peptide-mediated transcellular transport. The developments and limitations of nanomedicines, as well as expectations for better outcomes of tumor penetration, are discussed in this review.

Emerging Nanotherapeutic Approaches to Overcome Drug Resistance in Cancers with Update on Clinical Trials

A key issue with modern cancer treatments is the emergence of resistance to conventional chemotherapy and molecularly targeted medicines. Cancer nanotherapeutics were created in order to overcome the inherent limitations of traditional chemotherapeutics. Over the last few decades, cancer nanotherapeutics provided unparalleled opportunities to understand and overcome drug resistance through clinical assessment of rationally designed nanoparticulate delivery systems. In this context, various design strategies such as passive targeting, active targeting, nano-drug, and multimodal nano-drug combination therapy provided effective cancer treatment. Even though cancer nanotherapy has made great technological progress, tumor biology complexity and heterogeneity and a lack of comprehensive knowledge of nano-bio interactions remain important roadblocks to future clinical translation and commercialization. The current developments and advancements in cancer nanotherapeutics employing a wide variety of nanomaterial-based platforms to overcome cancer treatment resistance are discussed in this article. There is also a review of various nanotherapeutics-based approaches to cancer therapy, including targeting strategies for the tumor microenvironment and its components, advanced delivery systems for specific targeting of cancer stem cells (CSC), as well as exosomes for delivery strategies, and an update on clinical trials. Finally, challenges and the future perspective of the cancer nanotherapeutics to reverse cancer drug resistance are discussed.

Modelling the impact of nucleolin expression level on the activity of F3 peptide-targeted pH-sensitive pegylated liposomes containing doxorubicin

Strategies targeting nucleolin have enabled a significant improvement in intracellular bioavailability of their encapsulated payloads. In this respect, assessment of the impact of target cell heterogeneity and nucleolin homology across species (structurally and functionally) is of major importance. This work also aimed at mathematically modelling the nucleolin expression levels at the cell membrane, binding and internalization of pH-sensitive pegylated liposomes encapsulating doxorubicin and functionalized with the nucleolin-binding F3 peptide (PEGASEMP), and resulting cytotoxicity against cancer cells from mouse, rat, canine, and human origin. Herein, it was shown that nucleolin expression levels were not a limitation on the continuous internalization of F3 peptide-targeted liposomes, despite the saturable nature of the binding mechanism. Modeling enabled the prediction of nucleolin-mediated total doxorubicin exposure provided by the experimental settings of the assessment of PEGASEMP's impact on cell death. The former increased proportionally with nucleolin-binding sites, a measure relevant for patient stratification. This pattern of variation was observed for the resulting cell death in nonsaturating conditions, depending on the cancer cell sensitivity to doxorubicin. This approach differs from standard determination of cytotoxic concentrations, which normally report values of incubation doses rather than the actual intracellular bioactive drug exposure. Importantly, in the context of development of nucleolin-based targeted drug delivery, the structural nucleolin homology (higher than 84%) and functional similarity across species presented herein, emphasized the potential to use toxicological data and other metrics from lower species to infer the dose for a first-in-human trial.

Tumor microenvironment and nanotherapeutics: intruding the tumor fort

Over recent years, advancements in nanomedicine have allowed new approaches to diagnose and treat tumors. Nano drug delivery systems exploit the enhanced permeability and retention (EPR) effect and enter the tumor tissue's interstitial space. However, tumor barriers play a crucial role, and cause inefficient EPR or the homing effect. Mounting evidence supports the hypothesis that the components of the tumor microenvironment, such as the extracellular matrix, and cellular and physiological components collectively or cooperatively hinder entry and distribution of drugs, and therefore, limit the theragnostic applications of cancer nanomedicine. This abnormal tumor microenvironment plays a pivotal role in cancer nanomedicine and was recently recognized as a promising target for improving nano-drug delivery and their therapeutic outcomes. Strategies like passive or active targeting, stimuli-triggered nanocarriers, and the modulation of immune components have shown promising results in achieving anticancer efficacy. The present review focuses on the tumor microenvironment and nanoparticle-based strategies (polymeric, inorganic and organic nanoparticles) for intruding the tumor barrier and improving therapeutic effects.

Nanoparticles modified with vasculature-homing peptides for targeted cancer therapy and angiogenesis imaging

The two major challenges in cancer treatment include lack of early detection and ineffective therapies with various side effects. Angiogenesis is the key process in the growth, survival, invasiveness, and metastasis of many of cancerous tumors. Imaging of the angiogenesis could lead to diagnosis of tumors in the early stage and evaluation of the therapeutic responses. Angiogenic blood vessels express specific molecular markers different from normal blood vessels (in level or kind). This fact would make the tumor vasculature a suitable site to target therapeutics and imaging agents within the tumor. Surface modified nanoparticles using peptide ligands with high binding affinity to the vasculature markers, provide efficient delivery of therapeutic and imaging agents, while avoiding undesirable side effects. In this review, we discuss discoveries of various tumor targeting peptides useful for tumor angiogenesis imaging and targeted therapy with emphasis on surface modified nanomedicines using vasculature targeting peptides.

Ligand-Targeted Delivery of Photosensitizers for Cancer Treatment

Photodynamic therapy (PDT) is a promising cancer treatment which involves a photosensitizer (PS), light at a specific wavelength for PS activation and oxygen, which combine to elicit cell death. While the illumination required to activate a PS imparts a certain amount of selectivity to PDT treatments, poor tumor accumulation and cell internalization are still inherent properties of most intravenously administered PSs. As a result, common consequences of PDT include skin photosensitivity. To overcome the mentioned issues, PSs may be tailored to specifically target overexpressed biomarkers of tumors. This active targeting can be achieved by direct conjugation of the PS to a ligand with enhanced affinity for a target overexpressed on cancer cells and/or other cells of the tumor microenvironment. Alternatively, PSs may be incorporated into ligand-targeted nanocarriers, which may also encompass multi-functionalities, including diagnosis and therapy. In this review, we highlight the major advances in active targeting of PSs, either by means of ligand-derived bioconjugates or by exploiting ligand-targeting nanocarriers.

Fast DNA Extraction with Polyacrylamide Microspheres for Polymerase Chain Reaction Detection

The fast and cost-effective DNA extraction is critical for all DNA-based detections. Here, we fabricated a new kind of polyacrylamide microsphere (PAMMP) in various sizes with two methods, spot polymerization (large size but low yield) and modified inverse microemulsion polymerization (small size but high yield). The fabricated PAMMPs have strong autofluorescence (fPAMMPs), including both visible fluorescence (VF) and near-infrared fluorescence (NIRF), which can remain very stable in various stringent conditions including strong acid and alkali and high temperature. The fabricated fPAMMPs were also highly positively charged, which could be used to effectively capture various biomolecules such as IRDye 800-labeled streptavidin and DNA. We thus developed a new method for rapid extraction (3-5 min) of DNA from various samples including bacteria, mammalian cells, plant and animal solid tissues, and human blood plasma using fPAMMPs. Moreover, the DNA captured on fPAMMPs (fPAMMP@DNA) could be effectively detected by both normal and quantitative PCR amplifications. Finally, we showed that NaBH₄ treatment removed autofluorescence in fPAMMPs (PAMMPs), which could also be applied to DNA extraction and PCR detection. In conclusion, we here fabricated new kinds of fPAMMPs and PAMMPs, developed a new rapid DNA extraction method, and demonstrated their useful applications in PCR detection.

Ligand-Installed Nanocarriers toward Precision Therapy

Development of drug-delivery systems that selectively target neoplastic cells has been a major goal of nanomedicine. One major strategy for achieving this milestone is to install ligands on the surface of nanocarriers to enhance delivery to target tissues, as well as to enhance internalization of nanocarriers by target cells, which improves accuracy, efficacy, and ultimately enhances patient outcomes. Herein, recent advances regarding the development of ligand-installed nanocarriers are introduced and the effect of their design on biological performance is discussed. Besides academic achievements, progress on ligand-installed nanocarriers in clinical trials is presented, along with the challenges faced by these formulations. Lastly, the future perspectives of ligand-installed nanocarriers are discussed, with particular emphasis on their potential for emerging precision therapies.

Nucleolin-based targeting strategies for cancer therapy: from targeted drug delivery to cytotoxic ligands

Cancer is currently the second leading cause of death worldwide and current therapeutic approaches remain ineffective in several cases. Therefore, there is a need to develop more efficacious therapeutic agents, especially for subtypes of cancer lacking targeted therapies. Limited drug penetration into tumors impairs the efficacy of therapies targeting cancer cells. One of the strategies to overcome this problem is targeting the more accessible tumor vasculature via molecules such as nucleolin, which is expressed at the surface of cancer and angiogenic endothelial cells, thus enabling a dual cellular targeting strategy. In this review, we present and discuss nucleolin-based targeting strategies that have been developed for cancer therapy, with a special focus on recent antibody-based approaches.

Engineered 3D Model of Cancer Stem Cell Enrichment and Chemoresistance

Intraperitoneal dissemination of ovarian cancers is preceded by the development of chemoresistant tumors with malignant ascites. Despite the high levels of chemoresistance and relapse observed in ovarian cancers, there are no in vitro models to understand the development of chemoresistance in situ. Method: We describe a highly integrated approach to establish an in vitro model of chemoresistance and stemness in ovarian cancer, using the 3D hanging drop spheroid platform. The model was established by serially passaging non-adherent spheroids. At each passage, the effectiveness of the model was evaluated via measures of proliferation, response to treatment with cisplatin and a novel ALDH1A inhibitor. Concomitantly, the expression and tumor initiating capacity of cancer stem-like cells (CSCs) was analyzed. RNA-seq was used to establish gene signatures associated with the evolution of tumorigenicity, and chemoresistance. Lastly, a mathematical model was developed to predict the emergence of CSCs during serial passaging of ovarian cancer spheroids. Results: Our serial passage model demonstrated increased cellular proliferation, enriched CSCs, and emergence of a platinum resistant phenotype. In vivo tumor xenograft assays indicated that later passage spheroids were significantly more tumorigenic with higher CSCs, compared to early passage spheroids. RNA-seq revealed several gene signatures supporting the emergence of CSCs, chemoresistance, and malignant phenotypes, with links to poor clinical prognosis. Our mathematical model predicted the emergence of CSC populations within serially passaged spheroids, concurring with experimentally observed data. Conclusion: Our integrated approach illustrates the utility of the serial passage spheroid model for examining the emergence and development of chemoresistance in ovarian cancer in a controllable and reproducible format.

Transient Triplet Differential (TTD) Method for Background Free Photoacoustic Imaging

With the capability of presenting endogenous tissue contrast or exogenous contrast agents in deep biological samples at high spatial resolution, photoacoustic (PA) imaging has shown significant potential for many preclinical and clinical applications. However, due to strong background signals from various intrinsic chromophores in biological tissue, such as hemoglobin, achieving highly sensitive PA imaging of targeting probes labeled by contrast agents has remained a challenge. In this study, we introduce a novel technique called transient triplet differential (TTD) imaging which allows for substantial reduction of tissue background signals. TTD imaging detects directly the triplet state absorption, which is a special characteristic of phosphorescence capable dyes not normally present among intrinsic chromophores of biological tissue. Thus, these triplet state absorption PA images can facilitate "true" background free molecular imaging. We prepared a known phosphorescent dye probe, methylene blue conjugated polyacrylamide nanoparticles, with peak absorption at 660 nm and peak lowest triplet state absorption at 840 nm. We find, through studies on phantoms and on an in vivo tumor model, that TTD imaging can generate a superior contrast-to-noise ratio, compared to other image enhancement techniques, through the removal of noise generated by strongly absorbing intrinsic chromophores, regardless of their identity.

Anticancer activity and antibody-dependent cell-mediated cytotoxicity of novel anti-nucleolin antibodies

Nucleolin arises as a relevant target for cancer therapy, as it is overexpressed at the surface of cancer and angiogenic endothelial cells thus enabling a dual cellular targeting strategy. Immunotherapeutic strategies, albeit of proven therapeutic relevance, have been scarcely explored against this target. Therefore, this work aimed at engineering an anti-nucleolin VHH-based antibody capable of triggering anticancer immune responses. Herein, anti-nucleolin VHHs have been generated upon grafting F3 peptide-derived nucleolin-binding sequences onto a VHH CDR1 or CDR3. One of these nucleolin-binding CDR3-grafted VHH was subsequently fused to a human IgG1 Fc region, enabling a significant antibody-dependent cell-mediated cytotoxicity (ADCC). The generated anti-nucleolin VHH revealed increased binding and antiproliferative effects against cancer cells, relative to the parental VHH, while the VHH-Fc counterpart presented increased cytotoxicity relative to the corresponding VHH. This VHH-Fc also triggered an ADCC effect, in the nanomolar range, against a nucleolin-overexpressing cancer cell line. This effect was evidenced by a 2 or 1.7-fold increase of cell death, in the presence of PBMCs, relative to the parental VHH-Fc or the VHH counterpart, respectively. Overall, these formats represent the first anti-nucleolin VHHs and the first anti-nucleolin antibody with ADCC activity that have been successfully developed.

Meeting the needs of breast cancer: A nucleolin's perspective

A major challenge in the management of breast cancer disease has been the development of metastases. Finding new molecular targets and the design of targeted therapeutic approaches to improve the overall survival and quality of life of these patients is, therefore, of great importance. Nucleolin, which is overexpressed in cancer cells and tumor-associated blood vessels, have been implicated in various processes supporting tumorigenesis and angiogenesis. Additionally, its overexpression has been demonstrated in a variety of human neoplasias as an unfavorable prognostic factor, associated with a high risk of relapse and low overall survival. Hence, nucleolin has emerged as a relevant target for therapeutic intervention in cancer malignancy, including breast cancer. This review focus on the contribution of nucleolin for cancer disease and on the development of therapeutic strategies targeting this protein. In this respect, it also provides a critical analysis about the potential and pitfalls of nanomedicine for cancer therapy.

Nanomedicine applications in women's health: state of the art

State-of-the-art applications of nanomedicine have the potential to revolutionize the diagnosis, prevention, and treatment of a range of conditions and diseases affecting women’s health. In this review, we provide a synopsis of potential applications of nanomedicine in some of the most dominant fields of women’s health: mental health, sexual health, reproductive medicine, oncology, menopause-related conditions and dementia. We explore published studies arising from in vitro and in vivo experiments, and clinical trials where available, to reveal novel and highly promising therapeutic applications of nanomedicine in these fields. For the first time, we summarize the growing body of evidence relating to the use of nanomaterials as experimental tools for the detection, prevention, and treatment of significant diseases and conditions across the life course of a cisgender woman, from puberty to menopause; revealing the far-reaching and desirable theoretical impact of nanomedicine across different medical disciplines. We also present an overview of potential concerns regarding the therapeutic applications of nanomedicine and the factors currently restricting the growth of applied nanomedicine.

Peptides as drug delivery vehicles across biological barriers

Peptides are small biological molecules that are attractive in drug delivery and materials engineering for applications including therapeutics, molecular building blocks and cell-targeting ligands. Peptides are small but can possess complexity and functionality as larger proteins. Due to their intrinsic properties, peptides are able to overcome the physiological and transport barriers presented by diseases. In this review, we discuss the progress of identifying and using peptides to shuttle across biological barriers and facilitate transport of drugs and drug delivery systems for improved therapy. Here, the focus of this review is on rationally designed, phage display peptides, and even endogenous peptides as carriers to penetrate biological barriers, specifically the blood-brain barrier(BBB), the gastrointestinal tract (GI), and the solid tumor microenvironment (T). We will discuss recent advances of peptides as drug carriers in these biological environments. From these findings, challenges and potential opportunities to iterate and improve peptide-based approaches will be discussed to translate their promise towards the clinic to deliver drugs for therapeutic efficacy.

In vivo quantitative imaging of tumor pH by nanosonophore assisted multispectral photoacoustic imaging

Changes of physiological pH are correlated with several pathologies, therefore the development of more effective medical pH imaging methods is of paramount importance. Here, we report on an in vivo pH mapping nanotechnology. This subsurface chemical imaging is based on tumor-targeted, pH sensing nanoprobes and multi-wavelength photoacoustic imaging (PAI). The nanotechnology consists of an optical pH indicator, SNARF-5F, 5-(and-6)-Carboxylic Acid, encapsulated into polyacrylamide nanoparticles with surface modification for tumor targeting. Facilitated by multi-wavelength PAI plus a spectral unmixing technique, the accuracy of pH measurement inside the biological environment is not susceptible to the background optical absorption of biomolecules, i.e., hemoglobins. As a result, both the pH levels and the hemodynamic properties across the entire tumor can be quantitatively evaluated with high sensitivity and high spatial resolution in in vivo cancer models. The imaging technology reported here holds the potential for both research on and clinical management of a variety of cancers.

Background optical absorption of several biomolecules impedes an effective in vivo pH imaging in tumors. Here, the authors developed a visible light-based in vivo pH mapping method by coupling photoacoustic imaging and pH-responsive modified nanoparticles that selectively target tumor cells.

Matrix Density Engineering of Hydrogel Nanoparticles with Simulation-Guided Synthesis for Tuning Drug Release and Cellular Uptake

The use of a nanoparticle (NP)-based antitumor drug carrier has been an emerging strategy for selectively delivering the drugs to the tumor area and, thus, reducing the side effects that are associated with a high systemic dose of antitumor drugs. Precise control of drug loading and release is critical so as to maximize the therapeutic index of the NPs. Here, we propose a simple method of synthesizing NPs with tunable drug release while maintaining their loading ability, by varying the polymer matrix density of amine- or carboxyl-functionalized hydrogel NPs. We find that the NPs with a loose matrix released more cisplatin, with up to a 33 times faster rate. Also, carboxyl-functionalized NPs loaded more cisplatin and released it at a faster rate than amine-functionalized NPs. We performed detailed Monte Carlo computer simulations that elucidate the relation between the matrix density and drug release kinetics. We found good agreement between the simulation model and the experimental results for drug release as a function of time. Also, we compared the cellular uptake between amine-functionalized NPs and carboxyl-functionalized NPs, as a higher cellular uptake of NPs leads to improved cisplatin delivery. The amine-functionalized NPs can deliver 3.5 times more cisplatin into cells than the carboxyl-functionalized NPs. The cytotoxic efficacy of both the amine-functionalized NPs and the carboxyl-functionalized NPs showed a strong correlation with the cisplatin release profile, and the latter showed a strong correlation with the NP matrix density.

Nanoparticles and targeted drug delivery in cancer therapy

Surgery, chemotherapy, radiotherapy, and hormone therapy are the main common anti-tumor therapeutic approaches. However, the non-specific targeting of cancer cells has made these approaches non-effective in the significant number of patients. Non-specific targeting of malignant cells also makes indispensable the application of the higher doses of drugs to reach the tumor region. Therefore, there are two main barriers in the way to reach the tumor area with maximum efficacy. The first, inhibition of drug delivery to healthy non-cancer cells and the second, the direct conduction of drugs into tumor site. Nanoparticles (NPs) are the new identified tools by which we can deliver drugs into tumor cells with minimum drug leakage into normal cells. Conjugation of NPs with ligands of cancer specific tumor biomarkers is a potent therapeutic approach to treat cancer diseases with the high efficacy. It has been shown that conjugation of nanocarriers with molecules such as antibodies and their variable fragments, peptides, nucleic aptamers, vitamins, and carbohydrates can lead to effective targeted drug delivery to cancer cells and thereby cancer attenuation. In this review, we will discuss on the efficacy of the different targeting approaches used for targeted drug delivery to malignant cells by NPs.

Exploring the Potential of Nanotherapeutics in Targeting Tumor Microenvironment for Cancer Therapy

Advanced research in the field of cancer biology clearly demonstrated the key role of tumor microenvironment (TME) in cancer development and metastasis particularly in solid tumors. Components of TME, being non-neoplastic in nature provide supportive and permissive conditions for the growth of cancer cells. Hence it is important to modify TME in cancer therapy and this would be achieved by better understanding of TME morphological features and functioning of stromal components. Nanotechnology based drug delivery offers various advantages such as prolonged circulation time, delivery of cargo at desired site, improved bioavailability, reduced toxicity etc. over conventional chemotherapeutics. Abnormal characteristic features of TME play a paradoxical role in nanoparticulate drug delivery. Leaky vasculature, acidic and hypoxic conditions of TME helps in the accumulation of tailored nanoparticles whereas high interstitial pressure and dense stroma restrict the extravasation, homogenous distribution of nanocarriers in TME. This review mainly discusses the potential of nanotherapeutics in targeting TME by briefly discussing stromal components, therapeutic opportunities and barriers offered by TME for nanoparticulate drug delivery. Updated information on TME remodeling strategies for improved drug delivery and specific targeting of individual stromal components are also outlined.

In vitro characterization and in vivo ultrasound molecular imaging of nucleolin-targeted microbubbles

Nucleolin (NCL) plays an important role in tumor vascular development. An increased endothelial expression level of NCL has been related to cancer aggressiveness and prognosis and has been detected clinically in advanced tumors. Here, with a peptide targeted to NCL (F3 peptide), we created an NCL-targeted microbubble (MB) and compared the performance of F3-conjugated MBs with non-targeted (NT) MBs both in vitro and in vivo. In an in vitro study, F3-conjugated MBs bound 433 times more than NT MBs to an NCL-expressing cell line, while pretreating cells with 0.5 mM free F3 peptide reduced the binding of F3-conjugated MBs by 84%, n = 4, p < 0.001. We then set out to create a method to extract both the tumor wash-in and wash-out kinetics and tumor accumulation following a single injection of targeted MBs. In order to accomplish this, a series of ultrasound frames (a clip) was recorded at the time of injection and subsequent time points. Each pixel within this clip was analyzed for the minimum intensity projection (MinIP) and average intensity projection (AvgIP). We found that the MinIP robustly demonstrates enhanced accumulation of F3-conjugated MBs over the range of tumor diameters evaluated here (2-8 mm), and the difference between the AvgIP and the MinIP quantifies inflow and kinetics. The inflow and clearance were similar for unbound F3-conjugated MBs, control (non-targeted) and scrambled control agents. Targeted agent accumulation was confirmed by a high amplitude pulse and by a two-dimensional Fourier Transform technique. In summary, F3-conjugated MBs provide a new imaging agent for ultrasound molecular imaging of cancer vasculature, and we have validated metrics to assess performance using low mechanical index strategies that have potential for use in human molecular imaging studies.

Synthesis and evaluation of an 18 F-labeled derivative of F3 for targeting surface-expressed nucleolin in cancer and tumor endothelial cells

The surface overexpression of nucleolin provides an anchor for the specific attachment of biomolecules to cancer and angiogenic endothelial cells. The peptide F3 is a high-affinity ligand of the nucleolin receptor (NR) that has been investigated as a carrier to deliver biologically active molecules to tumors for both therapeutic and imaging applications. A site-specific PEGylated F3 derivative was radiolabeled with [18 F]Al-F. The binding affinity and cellular distribution of the compound was assessed in tumor (H2N) and tumor endothelial (2H-11) cells. Specific uptake via the NR was demonstrated by the siRNA knockdown of nucleolin in both cell lines. The partition and the plasma stability of the compound were assessed at 37°C. The enzyme-mediated site-specific modification of F3 to give NODA-PEG-F3 (NP-F3) was achieved. Radiolabeling with [18 F]Al-F gave 18 F-NP-F3. 18 F-NP-F3 demonstrated high affinity for cancer and tumor endothelial cells. The siRNA knockdown of nucleolin resulted in a binding affinity reduction of 50% to 60%, confirming cell surface binding via the NR. NP-F3 was stable in serum for 2 h. 18 F-NP-F3 is reported as the first 18 F-labeled F3 derivative. It was obtained in a site-specific, high-yield, and efficient manner and binds to surface NR in the low nanomolar range, suggesting it has potential as a tumor and angiogenesis tracer.

Modifying the tumor microenvironment using nanoparticle therapeutics

Treatment of cancer has come a long way from the initial 'radical surgeries' to the multimodality treatments. For the major part of the last century, cancer was considered as a monocellular disorder, and treatment strategies were designed according to that hypothesis. However, the mortality rate from cancer continued to be high and a comprehensive treatment remained elusive. Recent progress in research has demonstrated that tumors are a complex network of neoplastic and non-neoplastic cells. The non-neoplastic cells, which are collectively called stroma, assist in tumor survival and progression. It has been shown that disrupting the tumor-stromal balance leads to significant effects on the tumor survival, and effective treatment can be achieved by targeting one or more of the stromal components. In this review, we summarize the roles of various stromal components in promoting tumor progression, and discuss innovative nanoparticle-mediated drug targeting strategies for stromal depletion and the subsequent effects on the tumors. Perspectives and the future directions are also provided. WIREs Nanomed Nanobiotechnol 2016, 8:891-908. doi: 10.1002/wnan.1406 For further resources related to this article, please visit the WIREs website.

Novel polymeric nanoparticles targeting the lipopolysaccharides of Pseudomonas aeruginosa

Considering outburst of various infectious diseases globally, nanoparticle assisted targeted drug delivery has emerged as a promising strategy that can enhance the therapeutic efficacy and minimize the undesirable side effects of an antimicrobial agents. Molecular imprinting is a newly developed strategy that can synthesize a drug carrier with highly stable ligand-like 'cavity', may serve as a new platform of ligand-free targeted drug delivery systems. In this study, we use the amphiphilic lipopolysaccharides, derived from Pseudomonas aeruginosa as imprinting template and obtained an evenly distributed sub-40 nm polymeric nanoparticles by using inverse emulsion method. These molecularly imprinted nanoparticles (MIPNPs) showed specific binding to the lipopolysaccharide as determined by fluorescence polarization and microscale thermophoresis. MIPNPs showed selective recognition of target bacteria as detected by flow cytometry. Additionally, MIPNPs exhibited the in vivo targeting capabilities in both the keratitis model and meningitis model. Moreover, the photosensitizer methylene blue-loaded MIPNPs presented significantly strong inhibition of bacterial Growth, compared to non-imprinted controls for in vitro model of the photodynamic therapy. Our study shows an attempt to design a magic bullet by molecular imprinting that may provide a novel approach to generate synthetic carrier for targeting pathogen and treatment for a variety of infectious human diseases.

Polyethylenimine incorporation into hydrogel nanomatrices for enhancing nanoparticle-assisted chemotherapy

Addition of polyethylenimine into drug loaded hydrogel nanoparticle leads to enhanced cellular uptake, better ability to control drug release and deliver drugs to the cytosol, while evading the endosomes.

Nanomedicines for Endothelial Disorders

The endothelium lines the internal surfaces of blood and lymphatic vessels and has a critical role in maintaining homeostasis. Endothelial dysfunction is involved in the pathology of many diseases and conditions, including disorders such as diabetes, cardiovascular diseases, and cancer. Given this common etiology in a range of diseases, medicines targeting an impaired endothelium can strengthen the arsenal of therapeutics. Nanomedicine - the application of nanotechnology to healthcare - presents novel opportunities and potential for the treatment of diseases associated with an impaired endothelium. This review discusses therapies currently available for the treatment of these disorders and highlights the application of nanomedicine for the therapy of these major disease complications.

Design considerations for nanotherapeutics in oncology

Nanotherapeutics have improved the quality of life of cancer patients, primarily by reducing the adverse effects of chemotherapeutic agents, but improvements in overall survival are modest. This is in large part due to the fact that the enhanced permeability and retention effect, which is the basis for the use of nanoparticles in cancer, can be also a barrier to the delivery of nanomedicines. A careful design of nanoparticle formulations can overcome barriers posed by the tumor microenvironment and result in better treatments. In this review, we first discuss strengths and limitations of clinically-approved nanoparticles. Then, we evaluate design parameters that can be modulated to optimize delivery. The benefits of active tumor targeting and drug release rate on intratumoral delivery and treatment efficacy are also discussed. Finally, we suggest specific design strategies that should optimize delivery to most solid tumors and discuss under what conditions active targeting would be beneficial.

FROM THE CLINICAL EDITOR

Advances in nanotechnology have seen the introduction of new treatment modalities for cancer. The principle of action using nanocarriers for drug delivery is based mostly on the Enhanced Permeability and Retention effect. This phenomenon however, can also be a hindrance. In this article, the authors performed an in-depth review on various nanoparticle platforms in cancer therapeutics. They also suggested options to improve drug delivery, in terms of carrier design.

Nanoparticle approaches to combating drug resistance

Multidrug resistance (MDR) among cancer cells is a serious impediment to the success of conventional chemotherapy. The emergence of nanomedicine demonstrates great promise in overcoming MDR through multiple mechanisms. Nanoparticles have been shown to overcome the MDR at the tissue level through increased intratumoral accumulation resulting from enhanced permeation and retention, neovascular cell targeting, and externally triggered local drug release. Nanoparticles have also demonstrated the ability to overcome the MDR at the cellular/subcellular level by enhancing intracellular drug accumulation, improving drug-target accessibility, or even interfering with existing MDR mechanisms.

Strategies of polymeric nanoparticles for enhanced internalization in cancer therapy

In order to achieve long circulation time and high drug accumulation in the tumor sites via the EPR effects, anticancer drugs have to be protected by non-fouling polymers such as poly(ethylene glycol) (PEG), poly(ethylene oxide) (PEO), dextran, and poly(acrylic acid) (PAA). However, the dense layer of stealth polymer also prohibits efficient uptake of anticancer drugs by target cancer cells. For cancer therapy, it is often more desirable to accomplish rapid cellular uptake after anticancer drugs arriving at the pathological site, which could on one hand maximize the therapeutic efficacy and on the other hand reduce probability of drug resistance in cells. In this review, special attention will be focused on the recent potential strategies that can enable drug-loaded polymeric nanoparticles to rapidly recognize cancer cells, leading to enhanced internalization.

CD24+ Ovarian Cancer Cells Are Enriched for Cancer-Initiating Cells and Dependent on JAK2 Signaling for Growth and Metastasis

Ovarian cancer is known to be composed of distinct populations of cancer cells, some of which demonstrate increased capacity for cancer initiation and/or metastasis. The study of human cancer cell populations is difficult due to long requirements for tumor growth, interpatient variability, and the need for tumor growth in immune-deficient mice. We therefore characterized the cancer initiation capacity of distinct cancer cell populations in a transgenic murine model of ovarian cancer. In this model, conditional deletion of Apc, Pten, and Trp53 in the ovarian surface epithelium (OSE) results in the generation of high-grade metastatic ovarian carcinomas. Cell lines derived from these murine tumors express numerous putative stem cell markers, including CD24, CD44, CD90, CD117, CD133, and ALDH. We show that CD24(+) and CD133(+) cells have increased tumor sphere-forming capacity. CD133(+) cells demonstrated a trend for increased tumor initiation while CD24(+) cells versus CD24(-) cells had significantly greater tumor initiation and tumor growth capacity. No preferential tumor-initiating or growth capacity was observed for CD44(+), CD90(+), CD117(+), or ALDH(+) versus their negative counterparts. We have found that CD24(+) cells, compared with CD24(-) cells, have increased phosphorylation of STAT3 and increased expression of STAT3 target Nanog and c-myc. JAK2 inhibition of STAT3 phosphorylation preferentially induced cytotoxicity in CD24(+) cells. In vivo JAK2 inhibitor therapy dramatically reduced tumor metastases, and prolonged overall survival. These findings indicate that CD24(+) cells play a role in tumor migration and metastasis and support JAK2 as a therapeutic target in ovarian cancer.

Advanced targeted therapies in cancer: Drug nanocarriers, the future of chemotherapy

Cancer is the second worldwide cause of death, exceeded only by cardiovascular diseases. It is characterized by uncontrolled cell proliferation and an absence of cell death that, except for hematological cancers, generates an abnormal cell mass or tumor. This primary tumor grows thanks to new vascularization and, in time, acquires metastatic potential and spreads to other body sites, which causes metastasis and finally death. Cancer is caused by damage or mutations in the genetic material of the cells due to environmental or inherited factors. While surgery and radiotherapy are the primary treatment used for local and non-metastatic cancers, anti-cancer drugs (chemotherapy, hormone and biological therapies) are the choice currently used in metastatic cancers. Chemotherapy is based on the inhibition of the division of rapidly growing cells, which is a characteristic of the cancerous cells, but unfortunately, it also affects normal cells with fast proliferation rates, such as the hair follicles, bone marrow and gastrointestinal tract cells, generating the characteristic side effects of chemotherapy. The indiscriminate destruction of normal cells, the toxicity of conventional chemotherapeutic drugs, as well as the development of multidrug resistance, support the need to find new effective targeted treatments based on the changes in the molecular biology of the tumor cells. These novel targeted therapies, of increasing interest as evidenced by FDA-approved targeted cancer drugs in recent years, block biologic transduction pathways and/or specific cancer proteins to induce the death of cancer cells by means of apoptosis and stimulation of the immune system, or specifically deliver chemotherapeutic agents to cancer cells, minimizing the undesirable side effects. Although targeted therapies can be achieved directly by altering specific cell signaling by means of monoclonal antibodies or small molecules inhibitors, this review focuses on indirect targeted approaches that mainly deliver chemotherapeutic agents to molecular targets overexpressed on the surface of tumor cells. In particular, we offer a detailed description of different cytotoxic drug carriers, such as liposomes, carbon nanotubes, dendrimers, polymeric micelles, polymeric conjugates and polymeric nanoparticles, in passive and active targeted cancer therapy, by enhancing the permeability and retention or by the functionalization of the surface of the carriers, respectively, emphasizing those that have received FDA approval or are part of the most important clinical studies up to date. These drug carriers not only transport the chemotherapeutic agents to tumors, avoiding normal tissues and reducing toxicity in the rest of the body, but also protect cytotoxic drugs from degradation, increase the half-life, payload and solubility of cytotoxic agents and reduce renal clearance. Despite the many advantages of all the anticancer drug carriers analyzed, only a few of them have reached the FDA approval, in particular, two polymer-protein conjugates, five liposomal formulations and one polymeric nanoparticle are available in the market, in contrast to the sixteen FDA approval of monoclonal antibodies. However, there are numerous clinical trials in progress of polymer-protein and polymer-drug conjugates, liposomal formulations, including immunoliposomes, polymeric micelles and polymeric nanoparticles. Regarding carbon nanotubes or dendrimers, there are no FDA approvals or clinical trials in process up to date due to their unresolved toxicity. Moreover, we analyze in detail the more promising and advanced preclinical studies of the particular case of polymeric nanoparticles as carriers of different cytotoxic agents to active and passive tumor targeting published in the last 5 years, since they have a huge potential in cancer therapy, being one of the most widely studied nano-platforms in this field in the last years. The interest that these formulations have recently achieved is stressed by the fact that 90% of the papers based on cancer therapeutics with polymeric nanoparticles have been published in the last 6 years (PubMed search).

Development of nanoscale approaches for ovarian cancer therapeutics and diagnostics

Ovarian cancer is the deadliest of all gynecological cancers and the fifth leading cause of death due to cancer in women. This is largely due to late-stage diagnosis, poor prognosis related to advanced-stage disease, and the high recurrence rate associated with development of chemoresistance. Survival statistics have not improved significantly over the last three decades, highlighting the fact that improved therapeutic strategies and early detection require substantial improvements. Here, we review and highlight nanotechnology-based approaches that seek to address this need. The success of Doxil, a PEGylated liposomal nanoencapsulation of doxorubicin, which was approved by the FDA for use on recurrent ovarian cancer, has paved the way for the current wave of nanoparticle formulations in drug discovery and clinical trials. We discuss and summarize new nanoformulations that are currently moving into clinical trials and highlight novel nanotherapeutic strategies that have shown promising results in preclinical in vivo studies. Further, the potential for nanomaterials in diagnostic imaging techniques and the ability to leverage nanotechnology for early detection of ovarian cancer are also discussed.

Click conjugation of peptide to hydrogel nanoparticles for tumor-targeted drug delivery

Here we introduce a modified peptide-decorated polymeric nanoparticle (NP) for cancer cell targeting, which can deliver drugs, such as doxorubicin (Dox), to several kinds of cancer cells. Specifically, we employ a nucleolin-targeting NP, with a matrix based on a copolymer of acrylamide (AAm) and 2-carboxyethyl acrylate (CEA). The negatively charged co(CEA-AAm) NP was conjugated with a nucleolin-targeting F3 peptide using a highly efficient and specific copper(I) catalyzed azide-alkyne click reaction. F3 peptide binds to angiogenic tumor vasculatures and other nucleolin overexpressing tumor cells. Attaching F3 peptide onto the NP increases the NP uptake by the nucleolin-expressing glioma cell line 9L and the breast cancer cell line MCF-7. Notably, the F3-conjugated NPs show much higher uptake by the nucleolin-overexpressing glioma cell line 9L than that by the breast cancer cell line MCF-7, the latter having a lower expression of nucleolin on its plasma membrane surface. Moreover, the F3 peptide also dramatically enhances the uptake of co(CEA-AAm) NPs by the drug-resistant cell line NCI/ADR-RES. Also, with this F3-conjugated co(CEA-AAm) NP, a high loading and slow release of doxorubicin were achieved.

Tumor vasculature targeted photodynamic therapy for enhanced delivery of nanoparticles

Delivery of nanoparticle drugs to tumors relies heavily on the enhanced permeability and retention (EPR) effect. While many consider the effect to be equally effective on all tumors, it varies drastically among the tumors' origins, stages, and organs, owing much to differences in vessel leakiness. Suboptimal EPR effect represents a major problem in the translation of nanomedicine to the clinic. In the present study, we introduce a photodynamic therapy (PDT)-based EPR enhancement technology. The method uses RGD-modified ferritin (RFRT) as "smart" carriers that site-specifically deliver (1)O2 to the tumor endothelium. The photodynamic stimulus can cause permeabilized tumor vessels that facilitate extravasation of nanoparticles at the sites. The method has proven to be safe, selective, and effective. Increased tumor uptake was observed with a wide range of nanoparticles by as much as 20.08-fold. It is expected that the methodology can find wide applications in the area of nanomedicine.

Overcoming cancer multidrug resistance by codelivery of doxorubicin and verapamil with hydrogel nanoparticles

The efficacy of chemotherapy is often inhibited by multidrug resistance (MDR). A highly engineerable hydrogel nanoparticle (NP) serves as a carrier for the optimal codelivery to tumor cells of the chemodrug, doxorubicin (Dox) and the chemosensitizer, verapamil (Vera), aiming at alleviating tumor MDR. The hydrogel NPs are prepared via the copolymerization of acrylamide and 2-carboxyethyl acrylate. Dox and Vera are post-loaded into the respective NPs, with drug loading around 7.7 wt% and 8.0 wt%, respectively. The codelivery of Dox-NPs and Vera-NPs increases the intracellular accumulation of Dox, and significantly enhances the cell killing ability of Dox with respect to NCI/ADR-RES cells in vitro. These findings suggest that such codelivery nanoplatforms provide a promising route for overcoming tumor MDR.

Magnetic targeting of novel heparinized iron oxide nanoparticles evaluated in a 9L-glioma mouse model

PURPOSE

A novel PEGylated and heparinized magnetic iron oxide nano-platform (DNPH) was synthesized for simultaneous magnetic resonance imaging (MRI) and tumor targeting.

METHODS

Starch-coated magnetic iron oxide nanoparticles ("D") were crosslinked, aminated (DN) and then simultaneously PEGylated and heparinized with different feed ratios of PEG and heparin (DNPH1-4). DNPH products were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID). The magentic targeting of DNPH3, with appropriate amounts of conjugated PEG and heparin, in a mouse 9L-glioma subcutaneous tumor model was confirmed by magnetic resonance imaging (MRI)/electron spin resonance (ESR).

RESULTS

DNPH3 showed long circulating properties in vivo (half-life >8 h, more than 60-fold longer than that of parent D) and low reticuloendothelial system (RES) recognition in liver and spleen. Protamine, a model cationic protein, was efficiently loaded onto DNPH3 with a maximum loading content of 26.4 μg/mg Fe. Magnetic capture of DNPH3 in tumor site with optimized conditions (I.D. of 12 mg/kg, targeting time of 45 min) was up to 29.42 μg Fe/g tissue (12.26% I.D./g tissue).

CONCLUSION

DNPH3 showed the potential to be used as a platform for cationic proteins for simultaneous tumor targeting and imaging.

Nanotechnological strategies for therapeutic targeting of tumor vasculature

Neovascularization plays fundamental roles in tumor growth and metastasis. Tumor blood vessels are highly accessible and express various angiogenic markers that are either not present or are expressed at low levels in normal vessels, thereby serving as favorable targets for cancer therapy. Cancer nanotechnology, as an integrated platform, offers great opportunities for optimizing drug efficacy and pharmacokinetics while reducing side effects. Nanoparticles with tunable size, shape and surface modification have been exploited to achieve effective tumor vascular targeting. Here, we briefly introduce the signatures of tumor neovascularization and the review investigations on vascular-targeted anti-tumor nanomedicines. We also provide our perspectives on the promising fields of combination therapy and theranostic nanomedicines, as well as the challenges of nanotechnology-based cancer therapy. Furthermore, introducing new functionality would significantly consolidate the current development of nanomaterials based on tumor vasculature targeting.

Photo-cured hyaluronic acid-based hydrogels containing growth and differentiation factor 5 (GDF-5) for bone tissue regeneration

In this study we describe the generation and influences on in vitro and in vivo osteogenesis of photo-cured hyaluronic acid (HA) hydrogels loaded with growth and differentiation factor 5 (GDF-5). Prior to loading GDF-5, we characterized the release profiles from these hydrogels and tested their respective cell viability, differentiation and in vivo bone regeneration. The results from this testing indicated that GDF-5 was observed to release in a sustained manner from the HA hydrogels I-III. MTT and Live/Dead assays showed that the HA hydrogels I-III have good biocompatibility for use as scaffolds for bone tissue regeneration. In vitro cell tests showed a higher level of MC3T3-E1 cell proliferation and differentiation on HA hydrogels I-III than on HA hydrogel 0. Moreover, in vivo animal tests showed that the HA hydrogels I and III had a significant improvement on osteogenesis. Overall, our results suggest that the HA-based hydrogel is a good biomaterial to deliver osteogenic differentiation factors such as GDF-5, and GDF-5 can be useful as an effective alternative to aid new bone formation.