RGD peptide-modified dendrimer-entrapped gold nanoparticles enable highly efficient and specific gene delivery to stem cells

A review on dendrimer-based nanoconjugates and their intracellular trafficking in cancer photodynamic therapy

Nanotechnology-based cancer treatment has received considerable attention, and these treatments generally use drug-loaded nanoparticles (NPs) to target and destroy cancer cells. Nanotechnology combined with photodynamic therapy (PDT) has demonstrated positive outcomes in cancer therapy. Combining nanotechnology and PDT is effective in targeting metastatic cancer cells. Nanotechnology can also increase the effectiveness of PDT by targeting cells at a molecular level. Dendrimer-based nanoconjugates (DBNs) are highly stable and biocompatible, making them suitable for drug delivery applications. Moreover, the hyperbranched structures in DBNs have the capacity to load hydrophobic compounds, such as photosensitizers (PSs) and chemotherapy drugs, and deliver them efficiently to tumour cells. This review primarily focuses on DBNs and their potential applications in cancer treatment. We discuss the chemical design, mechanism of action, and targeting efficiency of DBNs in tumour metastasis, intracellular trafficking in cancer treatment, and DBNs' biocompatibility, biodegradability and clearance properties. Overall, this study will provide the most recent insights into the application of DBNs and PDT in cancer therapy.

Nanotechnology-Based Drug Delivery Systems for Treating Acute Kidney Injury

Acute kidney injury (AKI) is a disease that is characterized by a rapid decline in renal function and has a relatively high incidence in hospitalized patients. Sepsis, renal hypoperfusion, and nephrotoxic drug exposure are the main causes of AKI. The major therapy measures currently include supportive treatment, symptomatic treatment, and kidney transplantation. These methods are supportive treatments, and their results are not satisfactory. Fortunately, many new treatments that markedly improve the AKI therapy efficiency are emerging. These include antioxidant therapy, ferroptosis therapy, anti-inflammatory therapy, autophagy therapy, and antiapoptotic therapy. In addition, the development of nanotechnology has further promoted therapeutic effects on AKI. In this review, we highlight recent advances in the development of nanocarriers for AKI drug delivery. Emphasis has been placed on the latest developments in nanocarrier modification and design. We also summarize the applications of different nanocarriers in AKI treatment. Finally, the advantages and challenges of nanocarrier applications in AKI are summarized, and several nanomedicines that have been approved for clinical trials to treat diverse kidney diseases are listed.

Recent Advances in Nanomedicine for Ocular Fundus Neovascularization Disease Management

As an indispensable part of the human sensory system, visual acuity may be impaired and even develop into irreversible blindness due to various ocular pathologies. Among ocular diseases, fundus neovascularization diseases (FNDs) are prominent etiologies of visual impairment worldwide. Intravitreal injection of anti-vascular endothelial growth factor drugs remains the primary therapy but is hurdled by common complications and incomplete potency. To renovate the current therapeutic modalities, nanomedicine emerged as the times required, which is endowed with advanced capabilities, able to fulfill the effective ocular fundus drug delivery and achieve precise drug release control, thus further improving the therapeutic effect. This review provides a comprehensive summary of advances in nanomedicine for FND management from state-of-the-art studies. First, the current therapeutic modalities for FNDs are thoroughly introduced, focusing on the key challenges of ocular fundus drug delivery. Second, nanocarriers are comprehensively reviewed for ocular posterior drug delivery based on the nanostructures: polymer-based nanocarriers, lipid-based nanocarriers, and inorganic nanoparticles. Thirdly, the characteristics of the fundus microenvironment, their pathological changes during FNDs, and corresponding strategies for constructing smart nanocarriers are elaborated. Furthermore, the challenges and prospects of nanomedicine for FND management are thoroughly discussed.

Multifunctional nano-in-micro delivery systems for targeted therapy in fundus neovascularization diseases

Fundus neovascularization diseases are a series of blinding eye diseases that seriously impair vision worldwide. Currently, the means of treating these diseases in clinical practice are continuously evolving and have rapidly revolutionized treatment opinions. However, key issues such as inadequate treatment effectiveness, high rates of recurrence, and poor patient compliance still need to be urgently addressed. Multifunctional nanomedicine can specifically respond to both endogenous and exogenous microenvironments, effectively deliver drugs to specific targets and participate in activities such as biological imaging and the detection of small molecules. Nano-in-micro (NIM) delivery systems such as metal, metal oxide and up-conversion nanoparticles (NPs), quantum dots, and carbon materials, have shown certain advantages in overcoming the presence of physiological barriers within the eyeball and are widely used in the treatment of ophthalmic diseases. Few studies, however, have evaluated the efficacy of NIM delivery systems in treating fundus neovascular diseases (FNDs). The present study describes the main clinical treatment strategies and the adverse events associated with the treatment of FNDs with NIM delivery systems and summarizes the anatomical obstacles that must be overcome. In this review, we wish to highlight the principle of intraocular microenvironment normalization, aiming to provide a more rational approach for designing new NIM delivery systems to treat specific FNDs.

Multifunctional gold nanoparticles for osteoporosis: synthesis, mechanism and therapeutic applications

Osteoporosis is currently the most prevalent bone disorder worldwide and is characterized by low bone mineral density and an overall increased risk of fractures. To treat osteoporosis, a range of drugs targeting bone homeostasis have emerged in clinical practice, including anti-osteoclast agents such as bisphosphonates and denosumab, bone formation stimulating agents such as teriparatide, and selective oestrogen receptor modulators. However, traditional clinical medicine still faces challenges related to side effects and high costs of these types of treatments. Nanomaterials (particularly gold nanoparticles [AuNPs]), which have unique optical properties and excellent biocompatibility, have gained attention in the field of osteoporosis research. AuNPs have been found to promote osteoblast differentiation, inhibit osteoclast formation, and block the differentiation of adipose-derived stem cells, which thus is believed to be a novel and promising candidate for osteoporosis treatment. This review summarizes the advances and drawbacks of AuNPs in their synthesis and the mechanisms in bone formation and resorption in vitro and in vivo, with a focus on their size, shape, and chemical composition as relevant parameters for the treatment of osteoporosis. Additionally, several important and promising directions for future studies are also discussed, which is of great significance for prevention and treatment of osteoporosis.

Cell-binding peptides on the material surface guide stem cell fate of adhesion, proliferation and differentiation

Human cells, especially stem cells, need to communicate and interact with extracellular matrix (ECM) proteins, which not only serve as structural components but also guide and support cell fate and properties such as cell adhesion, proliferation, survival and differentiation. The binding of the cells with ECM proteins or ECM-derived peptides via cell adhesion receptors such as integrins activates several signaling pathways that determine the cell fate, morphological change, proliferation and differentiation. The development of synthetic ECM protein-derived peptides that mimic the biological and biochemical functions of natural ECM proteins will benefit academic and clinical application. Peptides derived from or inspired by specific ECM proteins can act as agonists of each ECM protein receptor. Given that most ECM proteins function in cell adhesion via integrin receptors, many peptides have been developed that bind to specific integrin receptors. In this review, we discuss the peptide sequence, immobilization design, reaction method, and functions of several ECM protein-derived peptides. Various peptide sequences derived from mainly ECM proteins, which are used for coating or grafting on dishes, scaffolds, hydrogels, implants or nanofibers, have been developed to improve the adhesion, proliferation or differentiation of stem cells and to culture differentiated cells. This review article will help to inform the optimal choice of ECM protein-derived peptides for the development of scaffolds, implants, hydrogels, nanofibers and 2D cell culture dishes to regulate the proliferation and direct the differentiation of stem cells into specific lineages.

Inorganic Nanoparticles-Based Systems in Biomedical Applications of Stem Cells: Opportunities and Challenges

Stem cells (SC) are a kind of cells with self renewing ability and multipotent differentiation, which can differentiate into many types of cells such as osteoblast, chondrocyte, neurocyte to treat disease like osteoporosis, osteoarthritis and Alzheimer's disease. Despite the development of novel methods for inducing cell differentiation, the inefficiency and complexity of controlling differentiation of stem cells remain a serious challenge, which necessary to develop a new and alternative approach for effectively controlling the direction of stem cell differentiation in vitro and in vivo in stem cells therapy. Recent advancement in nanotechnology for developing a new class of inorganic nanoparticles that exhibit unique chemical and physical properties holds promise for the treatment of stem cells. Over the last decade, inorganic nanoparticle-based approaches against stem cells have been directed toward developing nanoparticles with drug delivery, or utilizing nanoparticles for controlled cell behaviors, and applying nanoparticles for inducing cell differentiation directly. In addition, a strategy to functionalize inorganic nanoparticles as a nanoprobe towards enhanced penetration through near-infrared light or nuclear magnetic resonance has been receiving considerable interest by means of long-term tracking stem cell in vivo. This review summarizes and highlights the recent development of these inorganic nanoparticle-based approaches as potential therapeutics for controlling differentiation of stem cells and so on for stem cell therapy, along with current opportunities and challenges that need to be overcome for their successful clinical translation.

Genetic Engineering of Dendritic Cells Using Partially Zwitterionic Dendrimer-Entrapped Gold Nanoparticles Boosts Efficient Tumor Immunotherapy

Effective processing and cross-priming of tumor neoantigen by dendritic cells (DCs) to T cells for spontaneous immune response generation to effectively kill cancer cells remain challenging in cancer immunotherapy. Here, we report a general approach to genetically engineer DCs through silencing their YTHDF1 protein (an important reader protein responsible for RNA m⁶A methylation) expression via a dendrimeric non-viral vector to boost effective tumor immunotherapy. Poly(amidoamine) dendrimers of generation 5 were partially decorated with mannose and 1,3-propanesultone and then entrapped with gold (Au) nanoparticles. The created dendrimer nanoplatform has an Au core size of 1.8 nm; possesses desired stability, good cytocompatibility, and excellent YTHDF1 siRNA compression ability; and enables targeted gene silencing of DCs overexpressing mannose receptors to upregulate the expression of CD80 and CD86, markers of DCs maturation, potentially leading to tumor antigen cross-presentation. With these properties owned, the combination of YTHDF1 silencing of DCs with programmed cell death-ligand 1 antibody can boost the best immunotherapy of a xenografted melanoma tumor model through the created antitumor immune responses. Findings in this study demonstrate a general approach of genetic engineering of DCs via a dendrimeric non-viral vector to effectively boost antitumor immunotherapy.

Self-Assembled Nanoparticles for Tumor-Triggered Targeting Dual-Mode NIRF/MR Imaging and Photodynamic Therapy Applications

In this study, the self-assembling strategy was used to synthesize a therapeutic and diagnostic nanosystem for tumor-triggered targeting dual-mode near-infrared fluorescence (NIRF)/magnetic resonance (MR) imaging and photodynamic therapy applications. This theranostic nanosystem was synthesized based on the self-assembling of the short peptide (PLGVRGRGDC) and the gadolinium chelator (diethylenetriamine pentaacetic acid) functionalized amphiphilic DSPE-PEG₂₀₀₀, followed by loading with the insoluble photosensitizer therapeutic agent chlorin e6 (Ce6). The formed theranostic nanosystem can accumulate in the matrix metalloproteinase 2 (MMP2) rich tumor sites guided by the enhanced permeability and retention effect and MMP2-substrate peptide (PLGVR) targeting. After PLGVR was hydrolyzed in the tumor microenvironment by MMP2, the nanosystem was actively taken up by tumor cells via Arg-Gly-Asp (RGD) peptide-mediated internalization. With the coexistence of gadolinium and Ce6, the formed nanosystem can be used for both NIRF/MR dual-mode imaging and photodynamic therapy. These tumor-triggered targeting self-assembled nanoparticles with low cytotoxicity and high endocytosis efficiency can efficiently induce A549 cancer cell apoptosis under laser irradiation. Meanwhile, they possessed enhanced tumor-targeted NIRF/MR imaging ability and efficiently inhibited tumor growth with minimal side effects in mice bearing A549 lung cancer. Therefore, these self-assembled theranostic nanoparticles may have great potential for cancer clinical diagnosis and therapy.

Function and Mechanism of RGD in Bone and Cartilage Tissue Engineering

Bone and cartilage injury is common, tissue engineered scaffolds are potential means to repair. Because most of the scaffold materials used in bone and cartilage tissue engineering are bio-inert, it is necessary to increase the cellular adhesion ability of during tissue engineering reconstruction. The Arginine - Glycine - Aspartic acid (Arg-Gly-Asp, RGD) peptide family is considered as a specific recognition site for the integrin receptors. Integrin receptors are key regulators of cell-cell and cell-extracellular microenvironment communication. Therefore, the RGD polypeptide families are considered as suitable candidates for treatment of a variety of diseases and for the regeneration of various tissues and organs. Many scaffold material for tissue engineering and has been approved by US Food and Drug Administration (FDA) for human using. The application of RGD peptides in bone and cartilage tissue engineering was reported seldom. Only a few reviews have summarized the applications of RGD peptide with alloy, bone cements, and PCL in bone tissue engineering. Herein, we summarize the application progress of RGD in bone and cartilage tissue engineering, discuss the effects of structure, sequence, concentration, mechanical stimulation, physicochemical stimulation, and time stimulation of RGD peptide on cells differentiation, and introduce the mechanism of RGD peptide through integrin in the field of bone and cartilage tissue engineering.

Aptamer grafted nanoparticle as targeted therapeutic tool for the treatment of breast cancer

Breast carcinomas repeat their number and grow exponentially making it extremely frequent malignancy among women. Approximately, 70-80% of early diagnosed or non-metastatic conditions are treatable while the metastatic cases are considered ineffective to treat with current ample amount of therapy. Target based anti-cancer treatment has been in the limelight for decades and is perceived significant consideration of scientists. Aptamers are the 'coming of age' therapeutic approach, selected using an appropriate tool from the library of sequences. Aptamers are non-immunogenic, stable, and high-affinity ligand which are poised to reach the clinical benchmark. With the heed in nanoparticle application, the delivery of aptamer to the specific site could be enhanced which also protects them from nuclease degradation. Moreover, nanoparticles due to robust structure, high drug entrapment, and modifiable release of cargo could serve as a successful candidate in the treatment of breast carcinoma. This review would showcase the method and modified method of selection of aptamers, aptamers that were able to make its way towards clinical trial and their targetability and selectivity towards breast cancers. The appropriate usage of aptamer-based biosensor in breast cancer diagnosis have also been discussed.

Applications and developments of gene therapy drug delivery systems for genetic diseases

Genetic diseases seriously threaten human health and have always been one of the refractory conditions facing humanity. Currently, gene therapy drugs such as siRNA, shRNA, antisense oligonucleotide, CRISPR/Cas9 system, plasmid DNA and miRNA have shown great potential in biomedical applications. To avoid the degradation of gene therapy drugs in the body and effectively deliver them to target tissues, cells and organelles, the development of excellent drug delivery vehicles is of utmost importance. Viral vectors are the most widely used delivery vehicles for gene therapy in vivo and in vitro due to their high transfection efficiency and stable transgene expression. With the development of nanotechnology, novel nanocarriers are gradually replacing viral vectors, emerging superior performance. This review mainly illuminates the current widely used gene therapy drugs, summarizes the viral vectors and non-viral vectors that deliver gene therapy drugs, and sums up the application of gene therapy to treat genetic diseases. Additionally, the challenges and opportunities of the field are discussed from the perspective of developing an effective nano-delivery system.

RGD engineered dendrimer nanotherapeutic as an emerging targeted approach in cancer therapy

A bird's eye view is now demanded in the area of cancer research to suppress the suffering of cancer patient and mediate the lack of treatment related to chemotherapy. Chemotherapy is always preferred over surgery or radiation therapy, but they never met the patient's demand of safe medication. Targeted therapy has now been in research that could hinder the unnecessary effect of drug on normal cells but could affect the tumor cells in much efficient manner. Angiogenesis is process involved in development of new blood vessel that nourishes tumor growth. Integrin receptors are over expressed on cancer cells that play vital role in angiogenesis for growth and metastasis of tumor cell. A delivery of RGD based peptide to integrin targeted site could help in its successful binding and liberation of drug in tumor vasculature. Dendrimers, in addition to its excellent pharmacokinetic properties also helps to carry targeting ligand to site of tumor by successfully conjugating with them. The aim of this review is to bring light upon the role of integrin in cancer progression, interaction of RGD to integrin receptor and more importantly the RGD-dendrimer based targeted therapy for the treatment of various cancers.

Overcoming T Cell Exhaustion via Immune Checkpoint Modulation with a Dendrimer-Based Hybrid Nanocomplex

T cell exhaustion, in which dysfunctional T cells are limited in cytokine release and constrained in immune response, leads to immune escape of cancer cells and decreased efficiency of cancer immunotherapy. Direct regulation or blocking of programmed death 1 (PD-1) represents a promising strategy to overcome T cell exhaustion for reinvigorating anticancer immunity. Here, the construction of a 1,3-propanesultone (1,3-PS)-grafted zwitterionic dendrimer-entrapped gold nanoparticle platform chelated with Gd(III) (Gd-Au DENP-PS) for immune checkpoint modulation is reported. The developed Gd-Au DENP-PS possesses good stability, antifouling property, biocompatibility, and dual-mode computed tomography (CT)/magnetic resonance (MR) imaging functions, and allows for efficient packaging and serum-enhanced delivery of PD-1 siRNA to mediate PD-1 gene silencing in T cells in vitro, and also in vivo in a melanoma-bearing mouse model and in healthy aging mice. The dendrimer nanocomplexes or T cell-laden nanocomplexes enable suppression of tumor growth through the generation of significant effector CD8+ and CD4+ T cells, and the tumor immunotherapeutic potency can be further improved by combination with an indoleamine 2,3-dioxygenase inhibitor. This study identifies a new possibility with a functional dendrimer-based nanohybrid platform for dual-mode CT/MR imaging-guided cancer immunotherapy via the regulation of T cell exhaustion.

Assessment of 177 Lu-labeled carboxyl-terminated polyamidoamine (PAMAM) dendrimer-RGD peptide conjugate

Structurally unique polyamidoamine (PAMAM) dendrimers implanted with targeting biological moiety along with complexed radiometal constitute a favorable nano-system for diagnosis and therapy of targeted tumor sites. In the present study, carboxyl functionalities of PAMAM- generation 4 dendrimer (PAMAM-G4-COOH) were conjugated with ε-amino group of lysine of cRGDfK peptide to impart integrin α_v β₃ targeting capability. Reaction of p-NH₂ -Bn-DOTA with PAMAM was accomplished via acid-amine coupling using EDC/NHS for ¹⁷⁷ Lu-complexation. ¹⁷⁷ Lu-labeled nano-system, ¹⁷⁷ Lu-PAMAM-DOTA-cRGDfK demonstrated receptor-mediated uptake in murine melanoma B16F10 cells during in vitro cell uptake studies. In vivo biodistribution studies demonstrated low tumor uptake and retention of ¹⁷⁷ Lu-PAMAM-DOTA-cRGDfK which may be attributed to rapid blood clearance. However, fast clearance from non-target organs resulted in higher target to background ratio. Tumor uptake of targeted nano-system, ¹⁷⁷ Lu-PAMAM-DOTA-cRGDfK was observed to be significantly (p < 0.05) higher in comparison to ¹⁷⁷ Lu-PAMAM-DOTA without the targeting peptide. Inhibition studies with unlabeled cRGDfK resulted in 60% reduction in tumor uptake of ¹⁷⁷ Lu-PAMAM-DOTA-cRGDfK, indicating specificity of the developed nano-system towards integrin α_v β₃ receptors.

Targeting Non-coding RNA for Glioblastoma Therapy: The Challenge of Overcomes the Blood-Brain Barrier

Glioblastoma (GBM) is the most malignant form of all primary brain tumors, and it is responsible for around 200,000 deaths each year worldwide. The standard therapy for GBM treatment includes surgical resection followed by temozolomide-based chemotherapy and/or radiotherapy. With this treatment, the median survival rate of GBM patients is only 15 months after its initial diagnosis. Therefore, novel and better treatment modalities for GBM treatment are urgently needed. Mounting evidence indicates that non-coding RNAs (ncRNAs) have critical roles as regulators of gene expression. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are among the most studied ncRNAs in health and disease. Dysregulation of ncRNAs is observed in virtually all tumor types, including GBMs. Several dysregulated miRNAs and lncRNAs have been identified in GBM cell lines and GBM tumor samples. Some of them have been proposed as diagnostic and prognostic markers, and as targets for GBM treatment. Most ncRNA-based therapies use oligonucleotide RNA molecules which are normally of short life in circulation. Nanoparticles (NPs) have been designed to increase the half-life of oligonucleotide RNAs. An additional challenge faced not only by RNA oligonucleotides but for therapies designed for brain-related conditions, is the presence of the blood-brain barrier (BBB). The BBB is the anatomical barrier that protects the brain from undesirable agents. Although some NPs have been derivatized at their surface to cross the BBB, optimal NPs to deliver oligonucleotide RNA into GBM cells in the brain are currently unavailable. In this review, we describe first the current treatments for GBM therapy. Next, we discuss the most relevant miRNAs and lncRNAs suggested as targets for GBM therapy. Then, we compare the current drug delivery systems (nanocarriers/NPs) for RNA oligonucleotide delivery, the challenges faced to send drugs through the BBB, and the strategies to overcome this barrier. Finally, we categorize the critical points where research should be the focus in order to design optimal NPs for drug delivery into the brain; and thus move the Oligonucleotide RNA-based therapies from the bench to the clinical setting.

Impact of molecular rigidity on the gene delivery efficiency of core-shell tecto dendrimers

We report the construction of two types of core-shell tecto dendrimers (CSTDs) with different core rigidities to illustrate the impact of molecular rigidity on their gene delivery efficiency. Our study reveals that CSTDs designed with rigid cores enable promoted gene delivery, providing many possibilities for a wide range of gene delivery-associated biomedical applications.

A Dual-Responsive Platform Based on Antifouling Dendrimer-CuS Nanohybrids for Enhanced Tumor Delivery and Combination Therapy

Design of stimuli-responsive nanomedicine with enhanced tumor delivery for combination therapy still remains a great challenge. Here, a unique design of an antifouling-dendrimer-based nanoplatform with dual pH- and redox-responsiveness is reported to meet this challenge. First, generation 5 (G5) poly(amidoamine) dendrimers are modified with targeting ligand cyclic arginine-glycine-aspartic acid (RGD) peptide through a polyethylene glycol (PEG) spacer and zwitterion of thiolated N,N-dimethyl-cysteamine-carboxybetaine (CBT) via pH-responsive benzoicimine bond to form G5.NH₂ PEGRGDCBT conjugates. Then, doxorubicin (DOX) is linked to the functional G5 dendrimers through a redox-responsive disulfide bond, followed by entrapment of CuS nanoparticles within the dendrimers. The created functional dendrimer-CuS nanohybrids with a CuS core size of 3.6 nm display a good antifouling property and excellent photothermal conversion property in the second near-infrared window. In addition, the neutral surface charge of the nanohybrids is able to be switched to be positive in the tumor region with slightly acidic microenvironment due to the break of benzoicimine bond to promote their intracellular uptake, while the redox-sensitive disulfide bond affords the fast release of the conjugated DOX within tumor cells to exert its therapeutic effect. Taken together with the CuS cores, the created dendrimer-CuS nanohybrids enable enhanced combination chemotherapy and photothermal therapy of tumors.

Recent advances of dendrimer in targeted delivery of drugs and genes to stem cells as cellular vehicles

Stem cells can be used to repair dysfunctional and injured (or cancerous) tissues by delivering therapeutics. However, in comparison with other cells, it is harder to transfect drugs or genes into stem cells. Dendrimers have been considered as efficient vectors to deliver both genes and drugs to stem cells due to their unique properties including adjustable molecular weight and size, low toxicity, high loading capacity, and having multiple peripheral chemical agents which can be functionalized to improve deliverance efficiency. In this review, we discuss dendrimer-mediated drug and gene delivery to stem cells as cellular vehicles and the role of this strategy in treating a variety of disorders via regenerative medicine approaches.

Enhancing osteogenesis of adipose-derived mesenchymal stem cells using gold nanostructure/peptide-nanopatterned graphene oxide

Graphene derivatives are highly promising materials for use in stem-cell-based regenerative therapies, particularly for bone regeneration. Herein, we report a graphene oxide (GO)-based hybrid platform (GOHP) that is highly effective for guiding the osteogenesis of human adipose-derived mesenchymal stem cells (hAMSCs). A GO-coated indium tin oxide (ITO) substrate was electrochemically modified with Au nanostructures (GNSs), following which a cysteine-modified quadruple-branched arginine-glycine-aspartic acid was self-assembled on the ITO-GO-GNS hybrid via Au-S bonds. The synthesized GOHP, with the highest density of GNSs (deposition time of 120 s), exhibited the highest osteogenic differentiation efficiency based on the osteogenic marker expression level, osteocalcin expression, and osteoblastic mineralisation. Remarkably, although GO is known to be less efficient than the high-quality pure graphene synthesised via chemical vapour deposition (CVD), the fabricated GOHP exhibited an efficiency similar to that of CVD-grown graphene in guiding the osteogenesis of hAMSCs. The total RNA sequencing results revealed that CVD graphene and GOHP induced the osteogenesis of hAMSCs by upregulating the transcription factors related to direct osteogenesis, Wnt activation, and extracellular matrix deposition. Considering that GO is easy to produce, cost-effective, and biocompatible, the developed GOHP is highly promising for treating various diseases/disorders, including osteoporosis, rickets, and osteogenesis imperfecta.

Construction of Poly(amidoamine) Dendrimer/Carbon Dot Nanohybrids for Biomedical Applications

Design of intelligent hybrid nanoparticles that can integrate diagnosis and therapy components plays an important role in the field of nanomedicine. Poly(amidoamine) (PAMAM) dendrimers possessing a unique architecture and tunable functional groups have been widely developed for various biomedical applications. Carbon dots (CDs) are considered as a promising fluorescence probe or drug delivery system due to their stable fluorescence property and excellent biocompatibility. The distinctive merits of PAMAM dendrimers and CDs are amenable for them to be constructed as perfect nanohybrids for different biomedical applications, in particular for cancer nanomedicine. Here, the recent advances in the construction of PAMAM dendrimer/CD nanohybrids for diverse biomedical applications, in particular for sensing and cancer theranostics are summarized. Finally, the future perspectives of the PAMAM dendrimer/CD nanohybrids are also briefly discussed.

Smart nano-micro platforms for ophthalmological applications: The state-of-the-art and future perspectives

Smart nano-micro platforms have been extensively applied for diverse biomedical applications, mostly focusing on cancer therapy. In comparison with conventional nanotechnology, the smart nano-micro matrix can exhibit specific response to exogenous or endogenous triggers, and thus can achieve multiple functions e.g. site-specific drug delivery, bio-imaging and detection of bio-molecules. These intriguing techniques have expanded into ophthalmology in recent years, yet few works have been summarized in this field. In this work, we provide the state-of-the-art of diverse nano-micro platforms based on both the conventional materials (e.g. natural or synthetic polymers, lipid nanomaterials, metal and metal oxide nanoparticles) and emerging nanomaterials (e.g. up-conversion nanoparticles, quantum dots and carbon materials) in ophthalmology, with some smart nano/micro platformers highlighted. The common ocular diseases studied in the field of nano-micro systems are firstly introduced, and their therapeutic method and the related drawback in clinic treatment are presented. The recent progress of different materials for diverse ocular applications is then demonstrated, with the representative nano- and micro-systems highlighted in detail. At last, an in-depth discussion on the clinical translation challenges faced in this field and the future direction are provided. This review would allow the researchers to design more smart nanomedicines in a more rational manner for specific ophthalmology applications.

Three-Dimensional TEM Study of Dendrimer-Encapsulated Pt Nanoparticles for Visualizing Structural Characteristics of the Whole Organic-Inorganic Hybrid Nanostructure

Here, we report three-dimensional (3-D) visualization of dendrimer-encapsulated Pt nanoparticles (Pt DENs) by using 3-D electron tomography to reveal intricate structural characteristics of their whole organic-inorganic hybrid nanostructure. We reconstructed the 3-D spatial volume of Pt DENs by back-projecting a tilt series of two-dimensional (2-D) projections of Pt nanoparticles encapsulated inside dendrimers negatively stained with uranyl acetate. The direct 3-D visualization of Pt DENs elucidated their encapsulation characteristics with the spatial imaging of Pt nanoparticles embraced inside dendrimers in three dimensions. The encapsulation characteristics of Pt DENs were further verified with selective electrochemical poisoning experiments. In addition, quantitative 3-D structural characterization of Pt DENs provided more accurate and precise size distributions of nanoparticles than those obtained from conventional 2-D transmission electron microscopy analysis relying only on a 3-D structure projected on a 2-D plane.

Recent Progresses in Organic-Inorganic Nano Technological Platforms for Cancer Therapeutics

Nanotechnology offers promising tools in interdisciplinary research areas and getting an upsurge of interest in cancer therapeutics. Organic nanomaterials and inorganic nanomaterials bring revolutionary advancement in cancer eradication process. Oncology is achieving new heights under nano technological platform by expediting chemotherapy, radiotherapy, photo thermodynamic therapy, bio imaging and gene therapy. Various nanovectors have been developed for targeted therapy which acts as "Nano-bullets" for tumor cells selectively. Recently combinational therapies are catching more attention due to their enhanced effect leading towards the use of combined organicinorganic nano platforms. The current review covers organic, inorganic and their hybrid nanomaterials for various therapeutic action. The technological aspect of this review emphasizes on the use of inorganic-organic hybrids and combinational therapies for better results and also explores the future opportunities in this field.

Dual-mode endogenous and exogenous sensitization of tumor radiotherapy through antifouling dendrimer-entrapped gold nanoparticles

Development of a powerful sensitization system to alleviate radioresistance for enhanced tumor radiotherapy (RT) remains to be explored. Herein, we present a unique dual-mode endogenous and exogenous nanosensitizer based on dendrimer-entrapped gold nanoparticles (Au DENPs) to realize enhanced tumor RT. Methods: Generation 5 poly(amidoamine) dendrimers partially modified with 1,3-propanesultone were used for templated synthesis of Au NPs, and the created zwitterionic Au DENPs were adopted for serum-enhanced delivery of siRNA to lead to the knockdown of hypoxia-inducible factor-1α (HIF-1α) protein and downstream genes to relieve tumor invasion. The Au DENPs/siRNA polyplexes were also used for dual-mode endogenous and exogenous sensitization of tumor RT in vivo. Results: Due to the dual-mode endogenous sensitization through HIF-1α gene silencing and the exogenous sensitization through the existing Au component, enhanced RT of cancer cells in vitro and a tumor model in vivo can be realized, which was confirmed by enhanced cytotoxic reactive oxygen species (ROS) generation in vitro and double-strand DNA damage verified from the γ-H2AX protein expression in tumor cells in vivo. By integrating the advantages of HIF-1α gene silencing-induced downregulation of downstream genes and the dual-mode sensitization-enhanced RT, simultaneous inhibition of primary tumors and metastasis can be readily realized. Conclusions: The developed zwitterionic Au DENPs may be used as a promising platform for dual-mode endogenously and exogenously sensitized RT of other tumor types.

Targeted Combination of Antioxidative and Anti-Inflammatory Therapy of Rheumatoid Arthritis using Multifunctional Dendrimer-Entrapped Gold Nanoparticles as a Platform

Abundant reactive oxygen species and tumor necrosis factor-α (TNF-α) cytokine supply of M1-type macrophages boost rheumatoid arthritis (RA) pathological process. For efficient RA therapy, here a multifunctional nanoplatform is presented based on generation 5 (G5) poly(amidoamine) dendrimer-entrapped gold nanoparticles (Au DENPs) to achieve co-delivery of antioxidant alpha-tocopheryl succinate (α-TOS) and anti-inflammatory anti-TNF-α siRNA to macrophage cells. G5 dendrimers with amine termini are sequentially functionalized with 1,3-propane sultone (1,3-PS), α-TOS through a polyethylene glycol (PEG) spacer, and PEGylated folic acid (FA), and subsequently entrapped with Au NPs. The generated functional Au DENPs exhibit desired cytocompatibility, zwitterion-rendered antifouling property, and FA-mediated targeting specificity, enabling serum-enhanced siRNA delivery to M1-type macrophage cells. Meanwhile, the attached α-TOS affords enhanced oxidation resistance of macrophage cells. In vivo investigation shows that the treatment of a collagen-induced arthritis mouse model using α-TOS-modified Au DENPs/TNF-α siRNA polyplexes can achieve excellent combination therapy effect in inflammatory cytokines downregulation of RA lesion and bone erosions. The therapeutic efficacy is also supported by 3D micro-computed tomography analysis and TNF-α cytokine reduction of RA lesion joints in the mRNA, protein, and histology levels. The created multifunctional nanoplatform may be employed in antioxidative and anti-inflammatory combination therapy of RA.

Gene Therapy and Photothermal Therapy of Layer-by-Layer Assembled AuNCs /PEI/miRNA/ HA Nanocomplexes

BACKGROUND

MicroRNA (miRNA) therapy, which was widely considered to treat a series of cancer, has been confronted with numerous obstacles to being delivered into target cells because of its easy biodegradation and instability.

METHODS

In this research, we successfully constructed 11-mercaptoundecanoic acid modified gold nanocages (AuNCs)/polyethyleneimine (PEI)/miRNA/hyaluronic acid (HA) complexes (abbreviated as AuNCs/PEI/miRNA/HA) using a layer-by-layer method for target-specific intracellular delivery of miRNA by HA receptor mediated endocytosis.

RESULTS

The results of UV spectra, hydrodynamic diameter and zeta potential analyses confirmed the formation of AuNCs/PEI/ miRNA/HA complex with its average particle size of ca. 153 nm and surface charge of ca. -9.43 mV. Next, we evaluated the antitumor effect of the nanocomplex mediated by the combination of gene therapy and photothermal therapy (PTT) against hepatocellular carcinoma (HCC) in vitro.

CONCLUSION

Our experimental results indicated that the AuNCs/PEI/miRNA/HA complex effectively delivered miRNA to the target cells and its antitumor effect was significantly enhanced by the combination of gene therapy and photothermal therapy. In addition, anti-miR-181b could promote Bel-7402 cell arrest in S phase and improve TIMP-3 mRNA expression. All these results suggested that AuNCs/PEI/miRNA/HA gene delivery system with combination of gene therapy and photothermal therapy might be exploited for HCC treatment.

Nanofibrous Scaffolds Containing Hydroxyapatite and Microfluidic-Prepared Polyamidoamin/BMP-2 Plasmid Dendriplexes for Bone Tissue Engineering Applications

OBJECTIVE

The aim of this study is to fabricate functional scaffolds to gene delivery bone morphogenetic protein-2 (BMP-2) plasmid for bone formation in bone tissue engineering.

METHODS

Dendriplexes (DPs) of generation 4 polyamidoamin (G4-PAMAM)/BMP-2 plasmid were prepared through microfluidic (MF) platform. The physiochemical properties and toxicity of DPs were evaluated by DLS, AFM, FESEM and MTT assay. In order to create a suitable environment for stem cell growth and differentiation, poly-l-lactic acid (PLLA) and poly-l-lactic acid/poly (ethylene oxide) (PLLA/PEO) scaffolds containing hydroxyapatite nanoparticles (HA) and DPs were fabricated by the electrospinning method. The osteogenic potency of the scaffolds on human adipose tissue-derived mesenchymal stem cells (hASCs) was investigated.

RESULTS

The results revealed that tuning the physical properties of DPs by adjusting flow parameters in microfluidic platform can easily improve the cell viability compared to conventional bulk mixing method. Also, the result showed that the presence of HA and DPs in PLLA/PEO scaffold enhanced alkaline phosphatase (ALP) activity and increased the amount of deposited Ca, as well as, related to osteogenesis gen markers.

CONCLUSION

This study indicated that on using the MF platform in preparation of DPs and loading them along with HA in PLLA/PEO scaffold, the osteogenic differentiation of hASCs could be tuned.

Tissue-Specific Delivery of Oligonucleotides

From the initial discovery of short-interfering RNA (siRNA) and antisense oligonucleotides for specific gene knockdown at the posttranscriptional level to the current CRISPR-Cas9 system offering gene editing at the genomic level, oligonucleotides, in addition to their biological functions in storing and conveying genetic information, provide the most prominent solutions to targeted gene therapies. Nonetheless, looking into the future of curing cancer and acute diseases, researchers are only cautiously optimistic as the cellular delivery of these polyanionic biomacromolecules is still the biggest hurdle for their therapeutic realization. To overcome the delivery obstacle, oligonucleotides have been encapsulated within or conjugated with delivery vehicles for enhanced membrane penetration, improved payload, and tissue-specific delivery. Such delivery systems include but not limited to virus-based vehicles, gold-nanoparticle vehicles, formulated liposomes, and synthetic polymers. In this chapter, delivery challenges imposed by biological barriers are briefly discussed; followed by recent advances in tissue-specific oligonucleotide delivery utilizing both viral and nonviral delivery vectors, discussing their advantages, and how judicious design and formulation could improve and expand their potential as delivery vehicles.

Advances in Targeted Gene Delivery

Gene therapy has the potential to treat both acquired and inherited genetic diseases. Generally, two types of gene delivery vectors are used - viral vectors and non-viral vectors. Non-viral gene delivery systems have attracted significant interest (e.g. 115 gene therapies approved for clinical trials in 2018; clinicaltrials.gov) due to their lower toxicity, lack of immunogenicity and ease of production compared to viral vectors. To achieve the goal of maximal therapeutic efficacy with minimal adverse effects, the cell-specific targeting of non-viral gene delivery systems has attracted research interest. Targeting through cell surface receptors; the enhanced permeability and retention effect, or pH differences are potential means to target genes to specific organs, tissues, or cells. As for targeting moieties, receptorspecific ligand peptides, antibodies, aptamers and affibodies have been incorporated into synthetic nonviral gene delivery vectors to fulfill the requirement of active targeting. This review provides an overview of different potential targets and targeting moieties to target specific gene delivery systems.

Synthesis of Multiarm Peptide Dendrimers for Dual Targeted Thrombolysis

Current thrombolytic agents generally possess low specificity and pose a high risk of intracranial hemorrhage. Here, various generations of multiarm polylactic acid-polyglutamic acid peptide dendrimers were synthesized, and then nattokinase-combining magnetic Fe₃O₄ nanoparticles and RGD-modified dendrimers (Fe₃O₄-(4-PLA(G₃)₄)-RGD) were fabricated for targeted thrombi dissolution. Their in vitro and in vivo thrombolytic properties were determined. In vitro determination indicated that Fe₃O₄-(4-PLA(G₃)₄)-RGD/nattokinase provided 3-fold higher blood clot dissolution than that obtained with free nattokinase. An in vivo thrombolytic examination revealed that most of the thrombi were dissolved under an external magnetic field. In addition, there were many nanoparticles in vascular endothelial cells, demonstrating the RGD and magnetic dual targeting capacity of Fe₃O₄-(4-PLA(G₃)₄)-RGD/nattokinase. These results demonstrated that Fe₃O₄-(4-PLA(G₃)₄)-RGD nanoparticles not only will deliver targeted thrombolytic agents to enhance the efficacy of site-specific thrombolytic treatment but also have potential in the diagnosis of thrombotic disease in its early stages.

Adoptive cellular immunotherapy of tumors via effective CpG delivery to dendritic cells using dendrimer-entrapped gold nanoparticles as a gene vector

PEGylated Au DENPs ({(Au⁰)₂₅-G5·NH₂-mPEG₂₀}) are synthesized and used as a novel nonviral vector to deliver CpG to mature BMDCs for the subsequent activation of T cells for adoptive tumor immunotherapy.

Recent progress in biomedical applications of RGD-based ligand: From precise cancer theranostics to biomaterial engineering: A systematic review

Arginine-glycine-aspartic acid (RGD) peptide family is known as the most prominent ligand for extracellular domain of integrin receptors. Specific expression of these receptors in various tissue of human body and tight association of their expression profile with various pathophysiological conditions made these receptors a suitable targeting candidate for several disease diagnosis and treatment as well as regeneration of various organs. For these reasons, various forms of RGD-based integrins ligands have been greatly used in biomedical studies. Here, we summarized the last decade application progress of RGD for cancer theranostics, control of inflammation, thrombosis inhibition and critically discussed the effect of RGD peptides structure and sequence on the efficacy of gene/drug delivery systems in preclinical studies. Furthermore, we will show recent advances in application of RGD functionalized biomaterials for various tissue regenerations including cornea repair, artificial neovascularization and bone tissue regeneration. Finally, we analyzed clinically translatability of RGD peptides, considering examples of integrin ligands in clinical trials. In conclusion, prospects on using RGD peptide for precise drug delivery and biomaterial engineering are well discussed.

Raman observation of a molecular signaling pathway of apoptotic cells induced by photothermal therapy

Plasmonic nanoparticle (NP)-mediated photothermal therapy (PPTT) has been explored as a minimally invasive approach to cancer therapy and has progressed from concept to the early stage of clinical trials. Better understanding of the cellular and molecular response to PPTT is crucial for improvement of therapy efficacy and advancement of clinical application. However, the molecular mechanism underlying PPTT-induced apoptosis is still unclear and under dispute. In this work, we used nuclear-targeting Au nanostars (Au NSs) as both a photothermal agent to specifically induce apoptosis in cancer cells and as a surface enhanced Raman spectroscopy (SERS) probe to monitor the time-dependent SERS spectra of MCF-7 cells which are undergoing apoptosis. Through SERS spectra and their synchronous and asynchronous SERS correlation maps, the occurrence and dynamics of a cascade of molecular events have been investigated, and a molecular signaling pathway of PPTT-induced apoptosis, including release of cytochrome c, protein degradation, and DNA fragmentation, was revealed, which was also demonstrated by metabolomics, agarose gel electrophoresis, and western blot analysis, respectively. These results indicated that PPTT-induced apoptosis undergoes an intrinsic mitochondria-mediated apoptosis pathway. Combined with western blot results, this intrinsic mitochondria-mediated apoptosis pathway was further demonstrated to be initiated by a BH3-only protein, BID. This work is beneficial for not only improving the fundamental understanding of the molecular mechanism of apoptosis induced by PPTT but also for guiding the modulation of PPTT to drive forward its clinical application.

Zwitterion-functionalized dendrimer-entrapped gold nanoparticles for serum-enhanced gene delivery to inhibit cancer cell metastasis

We demonstrate a novel serum-enhanced gene delivery approach using zwitterion-functionalized dendrimer-entrapped gold nanoparticles (Au DENPs) as a non-viral vector for inhibition of cancer cell metastasis in vitro. Poly(amidoamine) dendrimers of generation 5 decorated with zwitterion carboxybetaine acrylamide (CBAA) and lysosome-targeting agent morpholine (Mor) were utilized to entrap gold NPs. We show that both Mor-modified and Mor-free Au DENPs are cytocompatible and can effectively deliver plasmid DNA encoding different reporter genes to cancer cells in medium with or without serum. Strikingly, due to the antifouling property exerted by the attached zwitterion CBAA, the gene delivery efficiency of Mor-modified Au DENPs and the Mor-free Au DENPs in the serum-containing medium are 1.4 and 1.7 times higher than the corresponding vector in serum-free medium, respectively. In addition, the Mor-free vector has a better gene expression efficiency than the Mor-modified one although the Mor modification enables the polyplexes to have enhanced cancer cell uptake. Wound healing and hypermethylated in cancer 1 (HIC1) protein expression assay data reveal that the expression of HIC1 gene in cancer cells enables effective inhibition of cell migration. Our findings suggest that the created zwitterion-functionalized Au DENPs may be employed as a powerful vector for serum-enhanced gene therapy of different diseases. STATEMENT OF SIGNIFICANCE: One major challenge in the non-viral gene delivery system is that the strong interaction between serum protein and the positively charged vector/gene polyplexes neutralize the positive charge of the polyplexes and form possible protein corona, thereby significantly reducing their cellular uptake efficiency and subsequent gene transfection outcome. Here we demonstrate the conceptual advances in the serum-enhanced gene delivery using zwitterionic modification of polycationic poly(amidoamine) (PAMAM) dendrimer-entrapped gold nanoparticles (Au DENPs). We demonstrate that partial zwitterionic modification of Au DENPs is able to confer them with antifouling property to resist serum protein adsorption. Hence the vector/DNA polyplexes are able to maintain their positive potentials and small hydrodynamic size in the serum environment, where serum solely play the role as a nutrition factor for enhanced gene delivery. We demonstrate that partial modification of zwitterion carboxybetaine acrylamide (CBAA) and morpholine (Mor) onto the surface Au DENPs renders the vector with both antifouling property and lysosome targeting ability, respectively. The generated functional Au DENPs can compact pDNA to form polyplexes that enable serum-enhanced gene expression. In particular, once complexed with hypermethylated in cancer 1 (HIC1) gene, the polyplexes can significantly inhibit cancer cell migration and metastasis.

Will Nanotechnology Bring New Hope for Stem Cell Therapy?

The potential of stem cell therapy has been shown in preclinical trials for the treatment of damage and replacement of organs and degenerative diseases. After many years of research, its clinical application is limited. Currently there is not a single stem cell therapy product or procedure. Nanotechnology is an emerging field in medicine and has huge potential due to its unique characteristics such as its size, surface effects, tunnel effects, and quantum size effect. The importance of application of nanotechnology in stem cell technology and cell-based therapies has been recognized. In particular, the effects of nanotopography on stem cell differentiation, proliferation, and adhesion have become an area of intense research in tissue engineering and regenerative medicine. Despite the many opportunities that nanotechnology can create to change the fate of stem cell technology and cell therapies, it poses several risks since some nanomaterials are cytotoxic and can affect the differentiation program of stem cells and their viability. Here we review some of the advances and the prospects of nanotechnology in stem cell research and cell-based therapies and discuss the issues, obstacles, applications, and approaches with the aim of opening new avenues for further research.

A brief review of cytotoxicity of nanoparticles on mesenchymal stem cells in regenerative medicine

Multipotent mesenchymal stem cells have shown great promise for application in regenerative medicine owing to their particular therapeutic effects, such as significant self-renewability, low immunogenicity, and ability to differentiate into a variety of specialized cells. However, there remain certain complicated and unavoidable problems that limit their further development and application. One of the challenges is to noninvasively monitor the delivery and biodistribution of transplanted stem cells during treatment without relying on behavioral endpoints or tissue histology, and it is important to explore the potential mechanisms to clarify how stem cells work in vivo. To solve these problems, various nanoparticles (NPs) and their corresponding imaging methods have been developed recently and have made great progress. In this review, we mainly discuss NPs used to label stem cells and their toxic effects on the latter, the imaging techniques to detect such NPs, and the current existing challenges in this field.

Enhanced Delivery of Plasmid DNA to Skeletal Muscle Cells using a DLC8-Binding Peptide and ASSLNIA-Modified PAMAM Dendrimer

Skeletal muscle is ideally suited and highly desirable as a target for therapeutic gene delivery because of its abundance, high vascularization, and high levels of protein expression. However, efficient gene delivery to skeletal muscle remains a current challenge. Besides the major obstacle of cell-specific targeting, efficient intracellular trafficking, or the cytosolic transport of DNA to the nucleus, must be demonstrated. To overcome the challenge of cell-specific targeting, herein we develop a generation 5-polyamidoamine dendrimer (G5-PAMAM) functionalized with a skeletal muscle-targeted peptide, ASSLNIA (G5-SMTP). Specifically, to demonstrate the feasibility of our approach, we prepared a complex of our G5-SMTP dendrimer with a plasmid encoding firefly luciferase and investigated its delivery to skeletal muscle cells. Luciferase assays indicated a threefold increase in transfection efficiency of C2C12 murine skeletal muscle cells using G5-SMTP when compared with nontargeting nanocarriers using unmodified G5. To further improve the transfection yield, we employed a cationic dynein light chain 8 protein (DLC8)-binding peptide (DBP) containing an internal sequence known to bind to the DLC8 of the dynein motor protein complex. Complexation of DBP with our targeting nanocarrier, that is, G5-SMTP, and our luciferase plasmid cargo resulted in a functional nanocarrier that showed an additional sixfold increase in transfection efficiency compared with G5-SMTP transfection alone. To our knowledge, this is the first successful use of two different functional nanocarrier components that enable targeted skeletal muscle cell recognition and increased efficiency of intracellular trafficking to synergistically enhance gene delivery to skeletal muscle cells. This strategy of targeting and trafficking can also be universally applied to any cell/tissue type for which a recognition domain exists.

Engineering Nanoparticles for Targeted Delivery of Nucleic Acid Therapeutics in Tumor

In the past 10 years, with the increase of investment in clinical nano-gene therapy, there are many trials that have been discontinued due to poor efficacy and serious side effects. Therefore, it is particularly important to design a suitable gene delivery system. In this paper, we introduce the application of liposomes, polymers, and inorganics in gene delivery; also, different modifications with some stimuli-responsive systems can effectively improve the efficiency of gene delivery and reduce cytotoxicity and other side effects. Besides, the co-delivery of chemotherapy drugs with a drug tolerance-related gene or oncogene provides a better theoretical basis for clinical cancer gene therapy.