Doxorubicin-tethered responsive gold nanoparticles facilitate intracellular drug delivery for overcoming multidrug resistance in cancer cells

Functionalized Nanomaterial Assembling and Biosynthesis Using the Extremophile Deinococcus radiodurans for Multifunctional Applications

The development of functionalized nanomaterial biosynthesis processes is important to expand many cutting-edge nanomaterial application areas. However, unclear synthesis mechanisms and low synthesis efficiency under various chemical stresses have limited the use of these biomaterials. Deinococcus radiodurans is an extreme bacterium well known for its exceptional resistance to radiation oxidants and electrophilic agents. This extremophile, which possesses a spontaneous self-assembled surface-layer (S-layer), has been an optimal model organism to study microbial nanomaterial biotemplates and biosynthesis under various stresses. This review summarizes the S-layers from D. radiodurans as an excellent biotemplate for various pre-synthesized nanomaterials and multiple applications, and highlights recent progresses about the biosynthesis of functionalized gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), as well as gold and silver bimetallic nanoparticles using D. radiodurans. Their formation mechanisms, properties, and applications are discussed and summarized to provide significant insights into the design or modification of functionalized nanomaterials via natural materials. Grand challenges and future directions to realize the multifunctional applications of these nanomaterials are highlighted for a better understanding of their biosynthesis mechanisms and functionalized modifications.

Gold-capped mesoporous silica nanoparticles as an excellent enzyme-responsive nanocarrier for controlled doxorubicin delivery

Mesoporous silica nanoparticles (MSNs) have ideal characteristics as next generation of controlled drug delivery systems. In this study, a MSN-based nanocarrier was fabricated and gold nanoparticle (GNP)-biotin conjugates were successfully grafted onto the pore outlets of the prepared MSN. This bioconjugate served as a capping agent with a peptide-cleavable linker sensitive to matrix metalloproteinases (MMPs), which are overexpressed extracellular proteolytic enzymes in cancerous tissue. The prepared nanocarriers were fully characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption/desorption, Fourier transform infra-red spectroscopy (FTIR), dynamic light scattering (DLS) and thermo gravimetric analysis (TGA). In vitro release studies showed efficient capping of MSNs with gold gate and controlled release of Doxorubicin (DOX) in the presence of matrix metalloproteinase-2 (MMP-2) and acidic pH values. High DOX-loading capacity (21%) and encapsulation efficiency (95.5%) were achieved using fluorescence technique. DOX-loaded nanocarriers showed high cytocompatibility and could efficiently induce cell death and apoptosis in the MMP-2 overexpressed cell lines. Moreover, Haemolysis, platelet activation and inflammatory responses assessment approved excellent hemocompatibility and minimal side effects by encapsulation of DOX in MSNs carrier.

Nanoparticle-mediated targeted drug delivery for breast cancer treatment

Breast cancer (BC) is the most common malignancy in women worldwide, and one of the deadliest after lung cancer. Currently, standard methods for cancer therapy including BC are surgery followed by chemotherapy or radiotherapy. However, both chemotherapy and radiotherapy often fail to treat BC due to the side effects that these therapies incur in normal tissues and organs. In recent years, various nanoparticles (NPs) have been discovered and synthesized to be able to selectively target tumor cells without causing any harm to the healthy cells or organs. Therefore, NPs-mediated targeted drug delivery systems (DDS) have become a promising technique to treat BC. In addition to their selectivity to target tumor cells and reduce side effects, NPs have other unique properties which make them desirable for cancer treatment such as low toxicity, good compatibility, ease of preparation, high photoluminescence (PL) for bioimaging in vivo, and high loadability of drugs due to their tunable surface functionalities. In this study, we summarize with a critical analysis of the most recent therapeutic studies involving various NPs-mediated DDS as alternatives for the traditional treatment approaches for BC. It will shed light on the significance of NPs-mediated DDS and serve as a guide to seeking for the ideal methodology for future targeted drug delivery for an efficient BC treatment.

Concepts of nanoparticle cellular uptake, intracellular trafficking, and kinetics in nanomedicine

Nanoparticle-based therapeutics and diagnostics are commonly referred to as nanomedicine and may significantly impact the future of healthcare. However, the clinical translation of these technologies is challenging. One of these challenges is the efficient delivery of nanoparticles to specific cell populations and subcellular targets in the body to elicit desired biological and therapeutic responses. It is critical for researchers to understand the fundamental concepts of how nanoparticles interact with biological systems to predict and control in vivo nanoparticle transport for improved clinical benefit. In this overview article, we review and discuss cellular internalization pathways, summarize the field`s understanding of how nanoparticle physicochemical properties affect cellular interactions, and explore and discuss intracellular nanoparticle trafficking and kinetics. Our overview may provide a valuable resource for researchers and may inspire new studies to expand our current understanding of nanotechnology-biology interactions at cellular and subcellular levels with the goal to improve clinical translation of nanomedicines.

Set of Highly Stable Amine- and Carboxylate-Terminated Dendronized Au Nanoparticles with Dense Coating and Nontoxic Mixed-Dendronized Form

The synthesis of a novel poly(propyleneimine) (PPI) dendron in gram scale as well as its use in the formation of a highly stable, dendronized gold nanoparticle (AuNP)-based drug delivery platform is described herein. The AuNP-based platform is composed of three complementary parts: (i) a 15 nm AuNP core, (ii) a heterofunctional thioctic acid-terminated tetraethylene glycol spacer, and (iii) a third-generation PPI dendron with a unique protonation profile and diverse end-group functionalization that allows for further derivatization. The prepared dendronized AuNPs are able to withstand several rounds of lyophilization cycles with no sign of aggregation, are stable in phosphate-buffered saline and Hanks' buffer as well as in serum, and are resistant to degradation by glutathione exchange reactions. This nanocarrier platform displays a dense coating, with >1400 dendrons/AuNPs, which will enable very high payload. Furthermore, while amine-terminated AuNPs expectedly showed cytotoxicity against the MCF-7 breast cancer cell line from a NP concentration of 1 nM, the mixed monolayer AuNPs (coated with 40/60 amine/carboxylate dendrons) interestingly did not exhibit any sign of toxicity at concentrations as high as 15 nM, similar to the carboxylate-terminated AuNPs. The described dendronized AuNPs address the current practical need for a stable NP-based drug delivery platform which is scalable and easily conjugable, has long-term stability in solution, and can be conveniently formulated as a powder and redispersed in desired buffer or serum.

Recent Progress in Macromolecule-Anchored Hybrid Gold Nanomaterials for Biomedical Applications

Gold nanoparticles (AuNPs), with elegant thermal, optical, or chemical properties due to quantum size effects, may serve as unique species for therapeutic or diagnostic applications. It is worth mentioning that their small size also results in high surface activity, leading to significantly impaired stability, which greatly hinders their biomedical utilizations. To overcome this problem, various types of macromolecular materials are utilized to anchor AuNPs so as to achieve advanced synergistic effect by dispersing, protecting, and stabilizing the AuNPs in polymeric-Au hybrid self-assemblies. In this review, the most recent development of polymer-AuNP hybrid systems, including AuNPs@polymeric nanoparticles, AuNPs@polymeric micelle, AuNPs@polymeric film, and AuNPs@polymeric hydrogel are discussed with respect to their different synthetic strategies. These sophisticated materials with diverse functions, oriented toward biomedical applications, are further summarized into several active domains in the areas of drug delivery, gene delivery, photothermal therapy, antibacterials, bioimaging, etc. Finally, the possible approaches for future design of multifunctional polymer-AuNP hybrids by combining hybrid chemistry with biological interface science are proposed.

Doxorubicin and Anti-PD-L1 Antibody Conjugated Gold Nanoparticles for Colorectal Cancer Photochemotherapy

Colorectal cancer (CRC) is the third leading cause of cancer-related death worldwide. The prognosis and overall survival of CRC are known to be significantly correlated with the overexpression of PD-L1. Since combination therapies can significantly improve therapeutic efficacy, we constructed doxorubicin (DOX) conjugated and anti-PD-L1 targeting gold nanoparticles (PD-L1-AuNP-DOX) for the targeted chemo-photothermal therapy of CRC. DOX and anti-PD-L1 antibody were conjugated to the α-terminal end group of lipoic acid polyethylene glycol N-hydroxysuccinimide (LA-PEG-NHS) using an amide linkage, and PD-L1-AuNP-DOX was constructed by linking LA-PEG-DOX, LA-PEG-PD-L1, and a short PEG chain on the surface of AuNP using thiol-Au covalent bonds. Physicochemical characterizations and biological studies of PD-L1-AuNP-DOX were performed in the presence of near-infrared (NIR) irradiation (biologic studies were conducted using cellular uptake, apoptosis, and cell cycle assays in CT-26 cells). PD-L1-AuNP-DOX (40.0 ± 3.1 nm) was successfully constructed and facilitated the efficient intracellular uptake of DOX as evidenced by pronounced apoptotic effects (66.0%) in CT-26 cells. PD-L1-AuNP-DOX treatment plus NIR irradiation significantly and synergistically suppressed the in vitro proliferation of CT-26 cells by increasing apoptosis and cell cycle arrest. The study demonstrates that PD-L1-AuNP-DOX in combination with synergistic targeted chemo-photothermal therapy has a considerable potential for the treatment of localized CRC.

Engineered Nanoparticles for Effective Redox Signaling During Angiogenic and Antiangiogenic Therapy

SIGNIFICANCE

Redox signaling plays a vital role in regulating various cellular signaling pathways and disease biology. Recently, nanomedicine (application of nanotechnology in biology and medicine) has been demonstrated to regulate angiogenesis through redox signaling. A complete understanding of redox signaling pathways influenced angiogenesis/antiangiogenesis triggered by therapeutic nanoparticles is extensively reviewed in this article. Recent Advances: In recent times, nanomedicines are regarded as the Trojan horses that could be employed for successful drug delivery, gene delivery, peptide delivery, disease diagnosis, and others, conquering barriers associated with conventional theranostic approaches.

CRITICAL ISSUES

Physiological angiogenesis is a tightly regulated process maintaining a balance between proangiogenic and antiangiogenic factors. The redox signaling is one of the main factors that contribute to this physiological balance. An aberrant redox signaling cascade can be caused by several exogenous and endogenous factors and leads to reduced or augmented angiogenesis that ultimately results in several disease conditions.

FUTURE DIRECTIONS

Redox signaling-based nanomedicine approach has emerged as a new platform for angiogenesis-related disease therapy, where nanoparticles promote angiogenesis via controlled reactive oxygen species (ROS) production and antiangiogenesis by triggering excessive ROS formation. Recently, investigators have identified different efficient nano-candidates, which modulate angiogenesis by controlling intracellular redox molecules. Considering the importance of angiogenesis in health care a thorough understanding of nanomedicine-regulated redox signaling would inspire researchers to design and develop more novel nanomaterials that could be used as an alternative strategy for the treatment of various diseases, where angiogenesis plays a vital role.

Zwitterionic Gel Coating Endows Gold Nanoparticles with Ultrastability

Colloidal stability of gold nanoparticles (GNPs) is of great importance for their applications. Although a number of ligands have been developed to protect GNPs, irreversible aggregation still happens under some particular conditions. Herein, we report a zwitterionic encapsulation strategy to endow GNPs with ultrastability. Each single GNP is coated with a cross-linked zwitterionic poly(ornithine methacrylamide) hydrogel thin-layer, which prevents particle aggregation under extremely harsh conditions, including lyophilization, strong acid solution, saturated salt solution, and concentrated alkali solution. In addition, the zwitterionic gel layer resists protein adsorption in the biological milieu, keeping the nanoparticles stable in full human blood serum. Furthermore, the amino-acid-derived polymer gel provides numerous conjugation sites for on-demand biomolecular functionalization. With all these merits, the zwitterionic gel coated GNPs hold great potential in many applications such as sensing and theragnostics.

Treating Polymicrobial Infections in Chronic Diabetic Wounds

This review provides a comprehensive summary of issues associated with treating polyclonal bacterial biofilms in chronic diabetic wounds. We use this as a foundation and discuss the alternatives to conventional antibiotics and the emerging need for suitable drug delivery systems. In recent years, extraordinary advances have been made in the field of nanoparticle synthesis and packaging. However, these systems have not been incorporated into the clinic for treatments other than for cancer or severe genetic diseases. We present a unifying perspective on how the field is evolving and the need for an early amalgamation of engineering principles and a biological understanding of underlying phenomena in order to develop a therapy that is translatable to the clinic in a shorter time.

Drug-loaded exosomal preparations from different cell types exhibit distinctive loading capability, yield, and antitumor efficacies: a comparative analysis

Background

Despite tremendous advancement, cancer still remains one of the leading causes of death worldwide. Inefficiency of current drug delivery regimens is one important factor that limits the therapeutic efficacy of existing drugs, thus contributing to cancer mortality. To address this limitation, synthetic nanotechnology-based delivery systems have been developed; however, they raise concern of inducing adverse immunogenic reactions. Exosomes (Exos) are nonimmunogenic nanosized vesicles that have received significant attention as efficient drug delivery system.

Methods

Drug loading in Exos were achieved by incubating different cell types viz pancreatic cancer cells (PCCs), pancreatic stellate cells (PSCs), and macrophages (MØs) with Doxorubicin (DOX). Differential ultracentrifugation was performed to isolate exosome and their size was determined by dynamic light scattering analysis. The efficacy of drug packaging into Exos was evaluated by HPLC. Flow cytometry was performed to examine the apoptosis. Cell viability was determined using the WST-1 assay.

Results

PCCs shed the most Exos and were the most efficient in drug loading followed by MØs and PSCs as examined by HPLC quantification. However, when compared for antitumor efficacy, MØ-derived Exos loaded with DOX (MØ-Exo-DOX) showed highest activity followed by PSCs and PCCs.

Conclusion

These varying antitumor activities likely resulted from nondrug contents of Exos since we did not observe any significant differences in their uptake by the cancer cells. Altogether, our data suggest that donor cell-specific differences exist in Exos, which could influence their utility as drug carrier for therapeutic purposes.

MicroRNAs as a Novel Tool in the Diagnosis of Liver Lipid Dysregulation and Fatty Liver Disease

In recent years, metabolic disorder, especially fatty liver disease, has been considered a major challenge to global health. The attention of researchers focused on expanding knowledge of the regulation mechanism behind these diseases and towards the new diagnostics tools and treatments. The pathophysiology of the fatty liver disease is undoubtedly complex. Abnormal hepatic lipid accumulation is a major symptom of most metabolic diseases. Therefore, the identification of novel regulation factors of lipid metabolism is important and meaningful. As a new diagnostic tool, the function of microRNAs during fatty liver disease has recently come into notice in biological research. Accumulating evidence supports the influence of miRNAs in lipid metabolism. In this review, we discuss the potential role of miRNAs in liver lipid metabolism and the pathogenesis of fatty liver disease.

Adsorption of doxorubicin hydrochloride on glutaric anhydride functionalized Fe3O4@SiO2 magnetic nanoparticles

Since Fe₃O₄ nanoparticles synthesized by plant extracts possess good bio-compatibility and superparamagnetic properties, the possibility of these could be used as a carrier in drug delivery. In this work, doxorubicin hydrochloride (DOX), an anti-cancer drug, loaded on glutaric anhydride-functionalized magnetic nanoparticles (Fe₃O₄@SiO₂-Glu) was investigated at varying pH values for effective drug delivery. Various factors affecting the adsorption of DOX onto the Fe₃O₄@SiO₂-Glu were examined, where the adsorption efficiency of DOX reached 92% at a concentration of 20 mg/L employing 10 mg of Fe₃O₄@SiO₂-Glu at 303 K in pH 7.4. However, the adsorption efficiency of DOX was decreased to 18% at acidic pH value down to 3.0, implicating that the drug releasing process was controlled by pH. Adsorption kinetics was fitting to pseudo-second-order and the isothermal adsorption conformed to Freundlich isotherm. The morphology and surface composition of the synthesized Fe₃O₄@SiO₂-Glu were characterized by SEM, TEM, and N₂ adsorption/desorption isotherms, revealing that the specific surface area being 62.6 m²/g and the size ranging from ~30 to 50 nm. The zeta potential results indicated that Fe₃O₄@SiO₂-Glu were negatively charged in various pH from 3 to 8.5. Characterizations by FTIR and UV-Vis techniques suggested that the DOX was absorbed and it can be delivered by Fe₃O₄@SiO₂-Glu.

Recognition Sites for Cancer-targeting Drug Delivery Systems

BACKGROUND

Target-homing drug delivery systems are now gaining significant attention for use as novel therapeutic approaches in antitumor targeting for cancer therapy. Numerous targeted drug delivery systems have been designed to improve the targeting effects because these systems can display a range of favorable properties, thus, providing suitable characteristics for clinical applicability of anticancer drugs, such as increasing the solubility, and improving the drug distribution at target sites. The majority of these targeting systems are designed with respect to differences between cancerous and normal tissues, for instance, the low pH of tumor tissues or overexpressed receptors on tumor cell membranes. Due to the growing number of targeting possibilities, it is important to know the tumor-specific recognition strategies for designing novel, targeted, drug delivery systems. Herein, we identify and summarize literature pertaining to various recognition sites for optimizing the design of targeted drug delivery systems to augment current chemotherapeutic approaches.

OBJECTIVE

This review focuses on the identification of the recognition sites for developing targeted drug delivery systems for use in cancer therapeutics.

METHODS

We have reviewed and compiled cancer-specific recognition sites and their abnormal characteristics within tumor tissues (low pH, high glutathione, targetable receptors, etc.), tumor cells (receptor overexpression or tumor cell membrane changes) and tumor cell organelles (nuclear and endoplasmic reticular dysregulation) utilizing existing scientific literature. Moreover, we have highlighted the design of some targeted drug delivery systems that can be used as homing tools for these recognition sites.

RESULTS AND CONCLUSION

Targeted drug delivery systems are a promising therapeutic approach for tumor chemotherapy. Additional research focused on finding novel recognition sites, and subsequent development of targeting moieties for use with drug delivery systems will aid in the evaluation and clinical application of new and improved chemotherapeutics.

Precise control of apoptosis via gold nanostars for dose dependent photothermal therapy of melanoma

Precise induction and monitoring of cell apoptosis are significant for cancer treatment.

Advances in Receptor-Mediated, Tumor-Targeted Drug Delivery

Receptor-mediated drug delivery presents an opportunity to enhance therapeutic efficiency by accumulating drug within the tissue of interest and reducing undesired, off-target effects. In cancer, receptor overexpression is a platform for binding and inhibiting pathways that shape biodistribution, toxicity, cell binding and uptake, and therapeutic function. This review will identify tumor-targeted drug delivery vehicles and receptors that show promise for clinical translation based on quantitative in vitro and in vivo data. The authors describe the rationale to engineer a targeted drug delivery vehicle based on the ligand, chemical conjugation method, and type of drug delivery vehicle. Recent advances in multivalent targeting and ligand organization on tumor accumulation are discussed. Revolutionizing receptor-mediated drug delivery may be leveraged in the therapeutic delivery of chemotherapy, gene editing tools, and epigenetic drugs.

Differences among Unique Nanoparticle Protein Corona Constructs: A Case Study Using Data Analytics and Multi-Variant Visualization to Describe Physicochemical Characteristics

Gold nanoparticles (AuNPs) used in pharmaceutical treatments have been shown to effectively deliver a payload, such as an active pharmaceutical ingredient or image contrast agent, to targeted tissues in need of therapy or diagnostics while minimizing exposure, availability, and accumulation to surrounding biological compartments. Data sets collected in this field of study include some toxico- and pharmacodynamic properties (e.g., distribution and metabolism) but many studies lack information about adsorption of biological molecules or absorption into cells. When nanoparticles are suspended in blood serum, a protein corona cloud forms around its surface. The extent of the applications and implications of this formed cloud are unknown. Some researchers have speculated that the successful use of nanoparticles in pharmaceutical treatments relies on a comprehensive understanding of the protein corona composition. The work presented in this paper uses a suite of data analytics and multi-variant visualization techniques to elucidate particle-to-protein interactions at the molecular level. Through mass spectrometry analyses, corona proteins were identified through large and complex datasets. With such high-output analyses, complex datasets pose a challenge when visualizing and communicating nanoparticle-protein interactions. Thus, the creation of a streamlined visualization method is necessary. A series of user-friendly data informatics techniques were used to demonstrate the data flow of protein corona characteristics. Multi-variant heat maps, pie charts, tables, and three-dimensional regression analyses were used to improve results interpretation, facilitate an iterative data transfer process, and emphasize features of the nanoparticle-protein corona system that might be controllable. Data informatics successfully highlights the differences between protein corona compositions and how they relate to nanoparticle surface charge.

Multifunctional Mesoporous Silica Nanoprobes: Material Chemistry–Based Fabrication and Bio‐Imaging Functionality

Nanoparticles‐based bioimaging probes are attracting broad attention for various biomedical applications. As one of the mostly explored nanoplatforms, mesoporous silica nanoparticles (MSNs) show high clinical‐translation potential for diagnostic probing/imaging. Based on their tunable morphology, abundant surface chemistry, and well‐defined mesostructure, MSNs are regarded as the desirable platforms for constructing diverse nanoprobes via incorporation of a variety of functional moieties or components. In this review, the authors summarize and discuss recent progress in the rational design and fabrication of multifunctional mesoporous silica‐based composite nanoprobes for versatile bioimaging applications. Four kinds of methodologies for the fabrication of these mesoporous silica‐based nanoprobes are discussed, including encapsulating functional nanoparticles within a mesoporous silica shell, assembling functional nanoparticles on the surface of MSNs, dispersing nanoparticles into the nanometer‐scale mesopores of MSNs, and doping functional moieties into the framework of MSNs. The applications of mesoporous silica nanoprobes in magnetic resonance imaging, ultrasound imaging, computed tomography imaging, fluorescence imaging, positron emission computed tomography, photoacoustic (PA) imaging, and even multimodality imaging are discussed in detail. The biosafety of MSN‐based composite nanoplatforms as bioimaging nanoprobes is also highlighted, accompanied by a deep discussion on facing the challenges and future developments for guaranteeing their further potential clinical translation.

P-glycoprotein-targeted photodynamic therapy boosts cancer nanomedicine by priming tumor microenvironment

Cancer nanomedicines only modestly improve the overall survival of patients because their anticancer activity is limited by biological barriers posed by the tumor microenvironment. Currently, all the drugs in FDA-approved cancer nanomedicines are substrates for P-glycoprotein (Pgp), and thus, Pgp-mediated multidrug resistance (MDR) remains a hurdle for cancer nanomedicines.

Methods: In this study, Pgp-targeted photodynamic therapy (PDT) was developed to enhance the anticancer efficacy of nanomedicines by depleting MDR cancer cells as well as enhancing tumor penetration of nanomedicines. We first examined the Pgp specificity of our targeted PDT approach, and then tested combination therapy of PDT with Doxil in mixed tumor models of MDR cancer cells and stromal cells, mimicking human heterogeneous tumors.

Results: In vitro studies showed that the antibody-photosensitizer conjugates produced Pgp-specific cytotoxicity towards MDR cancer cells upon irradiation with a near-infrared light. The studies with a co-culture model of MDR cancer cells and stromal cells revealed synergistic effects in the combination therapy of PDT with Doxil. Using a mouse model of mixed tumors containing MDR cancer cells and stroma cells, we observed markedly enhanced tumor delivery of Doxil after PDT in vivo. We further examined the effects of the two modalities on individual cell populations and their synergism using an in vivo dual substrate bioluminescence assay. The results indicated that Pgp-targeted PDT specifically depleted MDR cancer cells and further enhanced Doxil's actions on both MDR cancer cells and stromal cells.

Conclusion: We conclude that our targeted PDT approach markedly enhances anticancer actions of nanomedicines by depleting MDR cancer cells and increasing their tumor penetration, and thereby, may provide an effective approach to facilitate translation of cancer nanomedicines.

Stimuli-Responsive Nano-Architecture Drug-Delivery Systems to Solid Tumor Micromilieu: Past, Present, and Future Perspectives

The microenvironment characteristics of solid tumors, renowned as barriers that harshly impeded many drug-delivery approaches, were precisely studied, investigated, categorized, divided, and subdivided into a complex diverse of barriers. These categories were further studied with a particular perspective, which makes all barriers found in solid-tumor micromilieu turn into different types of stimuli, and were considered triggers that can increase and hasten drug-release targeting efficacy. This review gathers data concerning the nature of solid-tumor micromilieu. Past research focused on the treatment of such tumors, the recent efforts employed for engineering smart nanoarchitectures with the utilization of the specified stimuli categories, the possibility of combining more than one stimuli for much-greater targeting enhancement, examples of the approved nanoarchitectures that already translated clinically as well as the obstacles faced by the use of these nanostructures, and, finally, an overview of the possible future implementations of smart-chemical engineering for the design of more-efficient drug delivery and theranostic systems and for making nanosystems with a much-higher level of specificity and penetrability features.

Fabrication of 6-gingerol, doxorubicin and alginate hydroxyapatite into a bio-compatible formulation: enhanced anti-proliferative effect on breast and liver cancer cells

Ample attention has been devoted to the construction of anti-cancer drug delivery systems with increased stability, and controlled and targeted delivery, minimizing toxic effects. In this study we have designed a magnetically attractive hydroxyapatite (m-HAP) based alginate polymer bound nanocarrier to perform targeted, controlled and pH sensitive drug release of 6-gingerol, doxorubicin, and their combination, preferably at low pH environments (pH 5.3). They have exhibited higher encapsulation efficiency which is in the range of 97.4-98.9% for both 6-gingerol and doxorubicin molecules whereas the co-loading has accounted for a value of 81.87 ± 0.32%. Cell proliferation assays, fluorescence imaging and flow cytometric analysis, demonstrated the remarkable time and dose responsive anti-proliferative effect of drug loaded nanoparticles on MCF-7 cells and HEpG2 cells compared with their neat counter parts. Also, these systems have exhibited significantly reduced toxic effects on non-targeted, non-cancerous cells in contrast to the excellent ability to selectively kill cancerous cells. This study has suggested that this HAP based system is a versatile carrier capable of loading various drug molecules, ultimately producing a profound anti-proliferative effect.

pH-triggered charge-reversal and redox-sensitive drug-release polymer micelles codeliver doxorubicin and triptolide for prostate tumor therapy

AIM

To significantly promote cancer cell uptake and to achieve combination therapy and on-demand drug release, a pH-triggered charge-switchable and redox-responsive drug-release nanovehicle was developed in this study.

MATERIALS AND METHODS

The nanocarrier was constructed by conjugating 3,3'-dithiodipropionic acid-modified doxorubicin (DTPA-DOX) and 2,3-dimethylmaleic anhydride (DMA) to the side amino groups of poly(ethylene glycol)-b-poly(L-lysine) (PEG-b-PLL) and by encapsulating triptolide (TRI) into the hydrophobic core. The surface charge of the obtained nanocarriers (DA-ss-DT) can change from negative to positive in response to tumor extracellular acidity pH, and the nanocarriers capably release two drugs in response to intracellular high glutathione (GSH) environment.

RESULTS

Compared to the control group, the in vitro cellular uptake of DA-ss-DT by human prostate cancer PC-3 cells was significantly promoted in slightly acidic conditions, and the drug could be rapidly released in the high concentration of GSH conditions. The in vitro and in vivo antitumor experiments exhibited that the DA-ss-DT nanoparticles have a great antitumor effect in comparison to the control group.

CONCLUSION

These findings demonstrated that the DA-ss-DT nanoparticles supply a useful strategy for promoting cellular uptake and synergetic anticancer therapy.

A two-dimensional fingerprint nanoprobe based on black phosphorus for bio-SERS analysis and chemo-photothermal therapy

Flake-shaped nanohybrids based on black phosphorus (BP) have been developed as multifunctional theranostic nanoplatforms for drug delivery, phototherapy and bioimaging. In this work, we report a facile strategy for fabrication of black phosphorus-Au nanoparticle hybrids (BP-AuNPs), which reveal an extraordinary near-infrared (NIR) photothermal transduction efficiency and drug delivery capacity. The applications of the nanocomposites as therapeutic agents for high-performance chemo-photothermal tumor therapy are accomplished in vitro and in vivo. BP-AuNPs also exhibit wonderful surface-enhanced Raman scattering (SERS) activity under NIR laser excitation with a low Raman background, allowing BP-AuNPs to be used as a promising two-dimensional (2D) fingerprint nanoprobe for bio-SERS analysis. The cellular component identification and label-free live-cell bioimaging based on this type of 2D SERS substrate are generally investigated, which open up promising new perspectives in nanomedicine, including diagnosis, imaging and therapy.

Multifunctional Gold Nanoparticle-Based Fluorescence Resonance Energy-Transfer Probe for Target Drug Delivery and Cell Fluorescence Imaging

Drug delivery system has a profound significance for imaging capabilities and monitoring apoptosis process precisely in cancer therapeutic field. Herein, we designed cysteamine (CS)-stabilized gold nanoparticles, CS-gold nanoparticles (AuNPs)-doxorubicin (DOX), for fluorescence-enhanced cell imaging and target drug delivery. For cancer therapy, DOX was incorporated to CS-AuNPs by disulfide linkages which could be cleaved by glutathione (GSH) in cancer cells specifically. In addition, red-emissive DOX was quenched effectively by particular quenching effect of fluorescence resonance energy transfer from DOX to AuNPs, rendering monitoring target drug release by visual luminescence. The released DOX-SH acted as an indicator for cancer cells with red fluorescence and was further used for stimuli-responsive drug therapy. After an overall investigation of detection for GSH, proapoptosis for cancer cells, and inhibition for tumor tissues in vivo, the CS-AuNPs-DOX nanoprobe shows an obviously enhanced performance. This proposal provides an intelligent strategy for cell imaging and drug delivery, which serves as a promising candidate for anticancer therapeutic applications.

pH and redox dual-responsive copolymer micelles with surface charge reversal for co-delivery of all-trans-retinoic acid and paclitaxel for cancer combination chemotherapy

BACKGROUND

Co-delivery all-trans-retinoic acid (ATRA) and paclitaxel (PTX) is an effective strategy for cancer therapy. However, in many previous reported ATRA conjugated co-delivery systems, the ATRA was released slower than PTX, and the total drug release of ATRA far lower than that of PTX.

PURPOSE

We designed and prepared a pH and redox dual responsive drug delivery system (DA-ss-NPs) co-delivery ATRA and PTX for cancer therapy. The surface charge of DA-ss-NPs could change from negative to positive under tumor slightly acidic microenvironment, and both drugs could be quickly released from DA-ss-NPs under intracellular high concentration of glutathione (GSH).

METHODS

The DA-ss-NPs were constructed by encapsulating PTX into the hydrophobic core of the polymer micelles, in which the polymer was synthesized by conjugating ATRA and 2,3-Dimethylmalefic anhydride (DMA) on side chains of Cystamine dihydrochloride (Cys) modified PEG-b-PAsp (named DA-ss-NPs). The surface charge of DA-ss-NPs under different pH conditions were detected. And the drug release was also measured under different concentration of GSH. The therapeutic effect of DA-ss-NPs were investigated in Human lung cancer A549 cells and A549 tumor-bearing mice.

RESULTS

The zeta potential of DA-ss-NPs was -16.3 mV at pH 7.4, and which changed to 16 mV at pH 6.5. Cell uptake experiment showed that more DA-ss-NPs were internalized by A549 cells at pH 6.5 than that at pH 7.4. In addition, in presence of 10 mM GSH at pH 7.4, about 75%-85% ATRA was released from DA-ss-NPs within 48 h; but less than 20% ATRA was released without GSH. In vivo antitumor efficiency showed that the DA-ss-NPs could affectively inhibite the tumor in compared with control groups.

CONCLUSION

The charge-reversal and GSH-responsive DA-ss-NPs provide an excellent platform for potential tumor therapy.

Hyaluronic acid-capped compact silica-supported mesoporous titania nanoparticles for ligand-directed delivery of doxorubicin

Mesoporous titania nanoparticles (MTN), owing to their high surface area to volume ratio and tunable pore sizes, appear capable of delivering sizable amounts of drug payloads, and hence, show considerable promise as drug delivery candidates in cancer therapy. We designed silica-supported MTN (MTNst) coated with hyaluronic acid (HA) to effectively deliver doxorubicin (DOX) for breast cancer therapy. The HA coating served a dual purpose of stabilizing the payload in the carriers as well as actively targeting the nanodevices to CD44 receptors. The so-formed HA-coated MTNst carrying DOX (HA/DOX-MTNst) had spheroid particles with a considerable drug-loading capacity and showed significantly superior in vitro cytotoxicity against MDA-MB-231 cells as compared to free DOX. HA/DOX-MTNst markedly improved the cellular uptake of DOX in an apparently CD44 receptor-dependent manner, and increased the number of apoptotic cells as compared to free DOX. These nanoplatforms accumulated in large quantities in the tumors of MDA-MB-231 xenograft tumor-bearing mice, where they significantly enhanced the inhibition of tumor growth compared to that observed with free DOX with no signs of acute toxicity. Based on these excellent results, we deduced that HA/DOX-MTNst could be successfully used for targeted breast cancer therapy. STATEMENT OF SIGNIFICANCE: This is the first study to use silica-supported mesoporous titania nanoparticles (MTNst) for doxorubicin (DOX) delivery to treat breast cancer, which exhibited effective and enhanced in vitro and in vivo apoptosis and tumor growth inhibition. Solid silica was used to support the mesoporous TiO₂ resulting in MTNst, which efficiently incorporated a high DOX payload. The hyaluronic acid (HA) coating over the MTNst surface served a dual purpose of first, stabilizing DOX inside the MTNst (capping agent), and second, directing the nanoplatform device to CD44 receptors that are highly expressed in MDA-MB-231 cells (targeting ligand). The NPs exhibited highly efficacious in vitro tumor-cell killing and excellent in vivo tumor regression, highlighting the enormous promise of this system for breast cancer therapy.

Programmable Metal/Semiconductor Nanostructures for mRNA-Modulated Molecular Delivery

Cytotoxic chemotherapeutics are important tools for the clinical treatment of a variety of solid tumors. However, their use is often complicated by multidrug resistance that can develop in patients, limiting the potencies of these agents. New strategies are needed to provide versatile systems that can respond to and disable resistance mechanisms. We demonstrate the use of a new family of materials, programmable metal/semiconductor nanostructures, for drug delivery and mRNA sensing in drug-resistant cells. These materials are composed of a central core gold nanoparticle surrounded by a layer of DNA-capped quantum dots. The modularity of these "core-satellite" assemblies allows for the construction of superstructures with controlled size and the incorporation of multiple functionalities for drug delivery. The DNA sequence within the nanoparticle specifically binds to an mRNA encoding an important drug resistance factor, MRP1, inside cancer cells, releasing a potent anticancer drug doxorubicin. This event triggers a turn-on fluorescence emission along with a downregulation of the MRP1 drug efflux pump, a main resistance factor for doxorubicin, yielding a remarkable improvement in therapeutic efficacy against drug-resistant cancer cells. This work paves the way for the development of programmable materials with multiple synergistic functionalities for biomedical applications.

The Impact of Metallic Nanoparticles on Stem Cell Proliferation and Differentiation

Nanotechnology has a wide range of medical and industrial applications. The impact of metallic nanoparticles (NPs) on the proliferation and differentiation of normal, cancer, and stem cells is well-studied. The preparation of NPs, along with their physicochemical properties, is related to their biological function. Interestingly, various mechanisms are implicated in metallic NP-induced cellular proliferation and differentiation, such as modulation of signaling pathways, generation of reactive oxygen species, and regulation of various transcription factors. In this review, we will shed light on the biomedical application of metallic NPs and the interaction between NPs and the cellular components. The in vitro and in vivo influence of metallic NPs on stem cell differentiation and proliferation, as well as the mechanisms behind potential toxicity, will be explored. A better understanding of the limitations related to the application of metallic NPs on stem cell proliferation and differentiation will afford clues for optimal design and preparation of metallic NPs for the modulation of stem cell functions and for clinical application in regenerative medicine.

Doxorubicin-conjugated pH-responsive gold nanorods for combined photothermal therapy and chemotherapy of cancer

Cancer chemotherapy can be hindered by drug resistance which leads to lower drug efficiency. Here, we have developed a drug delivery system that tethers doxorubicin to the surface of gold nanorods via a pH-sensitive linkage (AuNRs@DOX), for a combined photothermal and chemical therapy for cancer. First, AuNRs@DOX is ingested by HepG2 liver cancer cells. After endocytosis, the acidic pH triggers the release of doxorubicin, which leads to chemotherapeutic effects. The gold nanorods are not only carriers of DOX, but also photothermal conversion agents. In the presence of an 808 nm near-infrared laser, AuNRs@DOX significantly enhance the cytotoxicity of doxorubicin via the photothermal effect, which induces elevated apoptosis of hepG2 cancer cells, leading to better therapeutic effects in vitro and in vivo.

Aptamers as targeting ligands and therapeutic molecules for overcoming drug resistance in cancers

Traditional anticancer therapies are often unable to completely eradicate the tumor bulk due to multi-drug resistance (MDR) of cancers. A number of mechanisms such as micro-environmental stress and overexpression of drug efflux pumps are involved in the MDR process. Hence, therapeutic strategies for overcoming MDR are urgently needed to improve cancer treatment efficacy. Aptamers are short single-stranded oligonucleotides or peptides exhibiting unique three-dimensional structures and possess several unique advantages over conventional antibodies such as low immunogenicity and stronger tissue-penetration capacity. Aptamers targeting cancer-associated receptors have been explored to selectively deliver a therapeutic cargo (anticancer drugs, siRNAs, miRNAs and drug-carriers) to the intratumoral compartment where they can exert better tumor-killing effects. In this review, we summarize current knowledge of the multiple regulatory mechanisms of MDR, with a particular emphasis on aptamer-mediated novel therapeutic agents and strategies that seek to reversing MDR. The challenges associated with aptamer-based agents and approaches are also discussed.

Glutathione detonated and pH responsive nano-clusters of Au nanorods with a high dose of DOX for treatment of multidrug resistant cancer

Effects of nanosized drug delivery systems on cancer are often compromised due to their low drug loadings, premature drug release and multi-drug resistance (MDR). Herein, we reported a glutathione detonated and pH responsive nano-cluster of Au nanorods (AuNRs) with chemotherapeutic doxorubicin (DOX) and pre-chemosensitizer polycurcumin to treat MCF-7/ADR cells. The nano-cluster was prepared by self-assembling of AuNRs conjugated with DOX and amphiphilic poly(curcumin-co-dithiodipropionic acid)-b-biotinylated poly(ethylene glycol) via an emulsion/solvent evaporation technique, termed AuNR Cluster. The AuNR Cluster had a high drug loading (31.5% DOX), presenting much better aqueous solubility and stability at physiological pH than their individual AuNRs. The AuNR Cluster could be detonated to be their individual AuNRs at an intracellular concentration level of glutathione (GSH) (5 mM) and triggered to release DOX at an acidic pH (pH 6.8 or 5.0), which effectively facilitated cellular uptake of DOX (607 vs 356 a.u. for AuNRs at 12 h) and inhibited DOX efflux (471.33 vs 39.17 a.u. for free DOX at 24 h). The IC₅₀ value of DOX against MCF-7/ADR cells for AuNR Cluster was 4.15 µg/mL, much lower than that for free DOX (90.97 µg/mL). The AuNR Cluster took much more photothermal effects than their corresponding AuNRs and presented enhanced anti-tumor effect (IC₅₀: 2.61 µg/mL) under 808 nm laser irradiation.

STATEMENT OF SIGNIFICANCE

Nano-sized drug delivery systems for anti-MDR cancer is still a challenging task. Herein, AuNR Cluster was self-assembled by individual AuNRs via emulsion/solvent evaporation technique, having a structure consisting of hydrophobic DOX/PCDA-AuNR core and hydrophilic biotin-PEG chain shell. AuNR Cluster is detonated to disintegrate and yield its individual AuNRs at an intracellular concentration level of glutathione (5 mM) and triggered to release DOX at an acidic pH (6.8 or 5.0). In comparison with its individual AuNRs, AuNR Cluster has better water solubility and stability, greater photothermal effects under NIR irradiation, bigger cytotoxicity against MCF-7/ADR cells. AuNR Cluster is expected to be a potential nanomedicine for treatment of MDR cancer.

Gold Nanoparticles in Diagnostics and Therapeutics for Human Cancer

The application of nanotechnology for the treatment of cancer is mostly based on early tumor detection and diagnosis by nanodevices capable of selective targeting and delivery of chemotherapeutic drugs to the specific tumor site. Due to the remarkable properties of gold nanoparticles, they have long been considered as a potential tool for diagnosis of various cancers and for drug delivery applications. These properties include high surface area to volume ratio, surface plasmon resonance, surface chemistry and multi-functionalization, facile synthesis, and stable nature. Moreover, the non-toxic and non-immunogenic nature of gold nanoparticles and the high permeability and retention effect provide additional benefits by enabling easy penetration and accumulation of drugs at the tumor sites. Various innovative approaches with gold nanoparticles are under development. In this review, we provide an overview of recent progress made in the application of gold nanoparticles in the treatment of cancer by tumor detection, drug delivery, imaging, photothermal and photodynamic therapy and their current limitations in terms of bioavailability and the fate of the nanoparticles.

Tunable Control of Hydrogel Microstructure by Kinetic Competition between Self-Assembly and Crosslinking of Elastin-like Proteins

The fabrication of three dimensional "bead-string" microstructured hydrogels is rationally achieved by controlling the relative timing of chemical crosslinking and physical self-assembly processes of an engineered protein. To demonstrate this strategy, an elastin-like protein (ELP) amino acid sequence was selected to enable site-specific chemical crosslinking and thermoresponsive physical self-assembly. This method allows the tuning of material microstructures without altering the ELP amino acid sequence but simply through controlling the chemical crosslinking extent before the thermally induced, physical coacervation of ELP. A loosely crosslinked network enables ELP to have greater chain mobility, resulting in phase segregation into larger beads. By contrast, a network with higher crosslinking density has restricted ELP chain mobility, resulting in more localized self-assembly into smaller beads. As a proof of concept application for this facile assembly process, we demonstrate one-pot, simultaneous, dual encapsulation of hydrophilic and hydrophobic model drugs within the microstructured hydrogel and differential release rates of the two drugs from the material.

Alginate hydrogel co-loaded with cisplatin and gold nanoparticles for computed tomography image-guided chemotherapy

The biomedical applications of gold nanoparticles (AuNPs) have experienced rapid growth in recent years, due to their expected benefits in medical imaging and therapy. In this work, we report the development of a theranostic nanocomplex constructed from alginate hydrogel co-loaded with cisplatin and AuNPs (abbreviated as ACA) for simultaneous drug delivery and computed tomography imaging. CT26 cells derived from mouse colon adenocarcinoma were exposed to various concentrations of ACA nanocomplex (for 24 h) and the cytotoxicity was measured using MTT assay. Moreover, the cells treated with ACA nanocomplex were imaged in a computed tomography scanner and the contrast enhancement due to the presence of nanocomplex was assessed. The cytotoxicity results showed that ACA nanocomplex had a more potent chemotherapy efficacy than free cisplatin, so that ACA nanocomplex at the concentration of 5 µg/ml (per cisplatin) and 20 µg/ml of free cisplatin resulted in the same cytotoxicity (survival rate: 66%). The computed tomography imaging study revealed that ACA nanocomplex increased the brightness of computed tomography images, the computed tomography number value, and contrast-to-noise ratio (CNR). ACA nanocomplex can be presented as a computed tomography-traceable nanocarrier that allows to monitor the delivery of therapeutics by assessing their localized accumulation and in vivo biodistribution.

pH-Sensitive Multiligand Gold Nanoplatform Targeting Carbonic Anhydrase IX Enhances the Delivery of Doxorubicin to Hypoxic Tumor Spheroids and Overcomes the Hypoxia-Induced Chemoresistance

Hypoxia is a common feature of solid tumors contributing to resistance to chemotherapy. Selective delivery of chemotherapeutic drugs to hypoxic tumor niche remains an unsolved issue. For this purpose, we constructed a gold nanoplatform targeting carbonic anhydrase IX (CA IX) epitope, which is overexpressed in hypoxic tumor cells versus in normal tissues. We designed compatible low-molecular weight carbonic anhydrase inhibitor (CAI) ligands and doxorubicin (Dox) ligands and optimized protocols for efficient decoration of gold nanoparticles (Au NPs) to achieve both good targeting ligand density and optimum drug loading, while preserving colloidal stability. The optimized Dox-HZN-DTDP@Au NPs-LA-PEG2000-CAI (THZN) nanoplatform was proved to be very efficient toward killing HT-29 tumor cells, especially under hypoxic conditions, as compared with the nontargeting nanoplatform. This also mediated the effective release of doxorubicin in the lysosomes following internalization, as revealed by confocal microscopy. Furthermore, using tumor spheroids as a representative model for hypoxic solid tumors, our THZN nanoplatform enhanced the selective delivery of doxorubicin up to 2.5 times and minimized chemoresistance, showing better tumor drug penetration as compared to that in free drug treatment. Our technology is the first CA IX-targeting gold nanoplatform for efficient delivery of doxorubicin to hypoxic tumors in a controlled fashion, with the perspective to improve the therapy of solid tumors and minimize chemoresistance.

Chemical and Biological Sensing Using Hybridization Chain Reaction

Since the advent of its theoretical discovery more than 30 years ago, DNA nanotechnology has been used in a plethora of diverse applications in both the fundamental and applied sciences. The recent prominence of DNA-based technologies in the scientific community is largely due to the programmable features stored in its nucleobase composition and sequence, which allow it to assemble into highly advanced structures. DNA nanoassemblies are also highly controllable due to the precision of natural and artificial base-pairing, which can be manipulated by pH, temperature, metal ions, and solvent types. This programmability and molecular-level control have allowed scientists to create and utilize DNA nanostructures in one, two, and three dimensions (1D, 2D, and 3D). Initially, these 2D and 3D DNA lattices and shapes attracted a broad scientific audience because they are fundamentally captivating and structurally elegant; however, transforming these conceptual architectural blueprints into functional materials is essential for further advancements in the DNA nanotechnology field. Herein, the chemical and biological sensing applications of a 1D DNA self-assembly process known as hybridization chain reaction (HCR) are reviewed. HCR is a one-dimensional (1D) double stranded (ds) DNA assembly process initiated only in the presence of a specific short ssDNA (initiator) and two kinetically trapped DNA hairpin structures. HCR is considered an enzyme-free isothermal amplification process, which shows substantial promise and offers a wide range of applications for in situ chemical and biological sensing. Due to its modular nature, HCR can be programmed to activate only in the presence of highly specific biological and/or chemical stimuli. HCR can also be combined with different types of molecular reporters and detection approaches for various analytical readouts. While the long dsDNA HCR product may not be as structurally attractive as the 2D and 3D DNA networks, HCR is highly instrumental for applied biological, chemical, and environmental sciences, and has therefore been studied to foster a variety of objectives. In this review, we have focused on nucleic acid, protein, metabolite, and heavy metal ion detection using this 1D DNA nanotechnology via fluorescence, electrochemical, and nanoparticle-based methodologies.

Biocompatible properties of nano-drug carriers using TiO2-Au embedded on multiwall carbon nanotubes for targeted drug delivery

Nanomaterial-based drug carriers have become a hot spot of research at the interface of nanotechnology and biomedicine because they allow efficient loading, targeted delivery, controlled release of drugs, and therefore are promising for biomedical applications. The current study made an attempt to decorate the multiwalled carbon nanotubes (MWCNT) with titanium dioxide‑gold nanoparticles in order to enhance the biocompatibility for doxorubicin (DOX) delivery. The successful synthesis of nano drug carrier (NDC) was confirmed by XRD, XPS and UV-Visible spectroscopy. FESEM and TEM revealed that the morphology of NDC can be controlled by manipulating the reaction duration, MWCNT concentration and TiO₂-Au source concentration. Results showed that TiO₂ and Au nanoparticles were well coated on MWCNT. NDC had finely tuned biocompatible properties, as elucidated by hemolytic and antimicrobial assays. NDC also showed a high antioxidant potential, 80.7% expressed as ascorbic acid equivalents. Commercial DOX drug was utilized to treat A549 and MCF7 cancer cell lines showing improved efficiency by formulating it with NDC, which selectively delivered at the pH 5.5 with drug loading capacity of 0.45 mg/mL. The drug releasing capacity achieved by NDC was 90.66% for 10 h, a performance that far encompasses a wide number of current literature reports.