Gold nanoparticle-protein agglomerates as versatile nanocarriers for drug delivery

Protein-nanoparticle co-assembly supraparticles for drug delivery: Ultrahigh drug loading and colloidal stability, and instant and complete lysosomal drug release

Two frequent problems hindering clinical translation of nanomedicine are low drug loading and low colloidal stability. Previous efforts to achieve ultrahigh drug loading (>30 %) introduce new hurdles, including lower colloidal stability and others, for clinical translation. Herein, we report a new class of drug nano-carriers based on our recent finding in protein-nanoparticle co-assembly supraparticle (PNCAS), with both ultrahigh drug loading (58 % for doxorubicin, i.e., DOX) and ultrahigh colloidal stability (no significant change in hydrodynamic size after one year). We further show that our PNCAS-based drug nano-carrier possesses a built-in environment-responsive drug release feature: once in lysosomes, the loaded drug molecules are released instantly (<1 min) and completely (∼100 %). Our PNCAS-based drug delivery system is spontaneously formed by simple mixing of hydrophobic nanoparticles, albumin and drugs. Several issues related to industrial production are studied. The ultrahigh drug loading and stability of DOX-loaded PNCAS enabled the delivery of an exceptionally high dose of DOX into a mouse model of breast cancer, yielding high efficacy and no observed toxicity. With further developments, our PNCAS-based delivery systems could serve as a platform technology to meet the multiple requirements of clinical translation of nanomedicines.

Cationic dextrin nanoparticles for effective intracellular delivery of cytochrome C in cancer therapy

Intracellular protein delivery shows promise as a selective and specific approach to cancer therapy. However, a major challenge is posed by delivering proteins into the target cells. Despite the development of nanoparticle (NP)-based approaches, a versatile and biocompatible delivery system that can deliver active therapeutic cargo into the cytosol while escaping endosome degradation remains elusive. In order to overcome these challenges, a polymeric nanocarrier was prepared using cationic dextrin (CD), a biocompatible and biodegradable polymer, to encapsulate and deliver cytochrome C (Cyt C), a therapeutic protein. The challenge of endosomal escape of the nanoparticles was addressed by co-delivering the synthesized NP construct with chloroquine, which enhances the endosomal escape of the therapeutic protein. No toxicity was observed for both CD NPs and chloroquine at the concentration tested in this study. Spectroscopic investigations confirmed that the delivered protein, Cyt C, was structurally and functionally active. Additionally, the delivered Cyt C was able to induce apoptosis by causing depolarization of the mitochondrial membrane in HeLa cells, as evidenced by flow cytometry and microscopic observations. Our findings demonstrate that an engineered delivery system using CD NPs is a promising platform in nanomedicine for protein delivery applications.

Stimuli-triggered multilayer films in response to temperature and ionic strength changes for controlled favipiravir drug release

The block copolymer micelles and natural biopolymers were utilized to form layer-by-layer (LbL) films via electrostatic interaction, which were able to effectively load and controllably release favipiravir, a potential drug for the treatment of coronavirus epidemic. The LbL films demonstrated reversible swelling/shrinking behavior along with the manipulation of temperature, which could also maintain the integrity in the structure and the morphology. Due to dehydration of environmentally responsive building blocks, the drug release rate from the films was decelerated by elevating environmental temperature and ionic strength. In addition, the pulsed release of favipiravir was observed from the multilayer films under the trigger of temperature, which ensured the precise control in the content of the therapeutic reagents at a desired time point. The nanoparticle-based LbL films could be used for on-demandin vitrorelease of chemotherapeutic reagents.

Dynamic Hydrogen-Bonded Zinc Adeninate Framework (ZAF) for Immobilization of Catalytic DNA

Effective immobilization and delivery of genetic materials is at the forefront of biological and medical research directed toward tackling scientific challenges such as gene therapy and cancer treatment. Herein we present a biologically inspired hydrogen-bonded zinc adeninate framework (ZAF) consisting of zinc adeninate macrocycles that self-assemble into a 3D framework through adenine-adenine interactions. ZAF can efficiently immobilize DNAzyme with full protection against enzyme degradation and physiological conditions until it is successfully delivered into the nucleus. As compared to zeolitic imidazolate frameworks (ZIFs), ZAFs are twofold more biocompatible with a significant loading efficiency of 96 %. Overall, our design paves the way for expanding functional hydrogen-bonding-based systems as potential platforms for the loading and delivery of biologics.

Insight into the Lysozyme-Induced Aggregation of Aromatic Amino Acid-Functionalized Gold Nanoparticles: Impact of the Protein Conjugation and Lipid Corona on the Aggregation Phenomena

The aggregation and subsequent precipitation of gold nanoparticles (Au NPs) in the presence of protein molecules restrict the usefulness of NPs in biomedical applications. Till now, the influence of different properties of Au NPs (size, surface charge, surface coatings) and proteins (surface charge, chemical modification, folded and unfolded states) and pH and ionic strength of the solution on the aggregation of both Au NPs and proteins has been thoroughly discussed in the literature. However, the underlying different mechanistic pathways of the protein concentration-dependent aggregation of both Au NPs and proteins are poorly understood. The impact of the lipid corona on the protein-induced Au NP aggregation has remained an unresolved issue. In this context, we investigate the interaction of the negatively charged aromatic amino acid (phenylalanine and tyrosine)-functionalized gold nanoparticles (Au-AA NPs) with the positively charged globular protein lysozyme at different protein concentrations and compare the results with those of conventional citrate-functionalized Au NPs (Au-Cit NPs). Next, we conjugate lipids and proteins to Au NPs to impede the aggregation of Au NPs induced by the lysozyme. Our results reveal that the aggregation mechanism of the Au-AA NPs is distinctly different at low and high protein concentrations with the uniqueness of the Au-AA NPs over the Au-Cit NPs. Furthermore, we find that human serum albumin (HSA) protein-conjugated Au-AA and Au-Cit NPs are more effective in preventing the lysozyme-induced Au NP aggregation than bovine serum albumin (BSA)-conjugated Au NPs. For the first time, we also report the significant role of "hard" and "soft" lipid coronas in the aggregation of amino acid (phenylalanine)-functionalized gold nanoparticles in the presence of lysozyme protein.

Protein adsorption onto nanomaterials engineered for theranostic applications

The key role of biomolecule adsorption onto engineered nanomaterials for therapeutic and diagnostic purposes has been well recognized by the nanobiotechnology community, and our mechanistic understanding of nano-bio interactions has greatly advanced over the past decades. Attention has recently shifted to gaining active control of nano-bio interactions, so as to enhance the efficacy of nanomaterials in biomedical applications. In this review, we summarize progress in this field and outline directions for future development. First, we briefly review fundamental knowledge about the intricate interactions between proteins and nanomaterials, as unraveled by a large number of mechanistic studies. Then, we give a systematic overview of the ways that protein-nanomaterial interactions have been exploited in biomedical applications, including the control of protein adsorption for enhancing the targeting efficiency of nanomedicines, the design of specific protein adsorption layers on the surfaces of nanomaterials for use as drug carriers, and the development of novel nanoparticle array-based sensors based on nano-bio interactions. We will focus on particularly relevant and recent examples within these areas. Finally, we conclude this topical review with an outlook on future developments in this fascinating research field.

Biosynthesized Gold Nanoparticles Integrated Ointment Base for Repellent Activity Against Aedes aegypti L

The present study focused on preparing a nano-ointment base integrated with biogenic gold nanoparticles from Artemisia vulgaris L. leaf extract. As prepared, nano-ointment was characterized by using Fourier-transform infrared spectroscopy, and the morphology of the nano-ointment was confirmed through a scanning electron microscope. Initially, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide results showed nano-ointment cytocompatibility at different concentrations (20-200 μg/mL) against L929 cells. The in vitro hemolysis assay also revealed that the nano-ointment is biocompatible. Further studies confirmed that nano-ointment has repellent activity with various concentrations (12.5, 25, 50, 75, and 100 ppm). At 100 ppm concentration, the highest repellent activity was observed at 60-min protection time against the Aedes aegypti L. female mosquitoes. The results indicated that the increasing concentration of nano-ointment prolongs the protection time. Moreover, the outcome of this study provides an alternative nano-ointment to synthetic repellent and insecticides after successful clinical trials. It could be an eco-friendly, safer nano-bio repellent, which can protect from dengue fever mosquitoes.

Water-Soluble Chitosan Conjugated DOTA-Bombesin Peptide Capped Gold Nanoparticles as a Targeted Therapeutic Agent for Prostate Cancer

Introduction

Functionalization of water-soluble chitosan (WSCS) nanocolloids with, gold nanoparticles (AuNPs), and LyslLys3 (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)-bombesin 1–14 (DOTA-BBN) peptide affords an innovative pathway to produce prostate tumor cell-specific nanomedicine agents with potential applications in molecular imaging and therapy.

Methods

The preparation involves the production and full characterization of water-soluble chitosan (WSCS), via gamma (γ) rays (80 kGy) irradiation, followed by DOTA-BBN conjugation for subsequent use as an effective template toward the synthesis of tumor cell-specific AuNPs-WSCS-DOTA-BBN.

Results

The WSCS-DOTA-BBN polymeric nanoparticles (86 ± 2.03 nm) served multiple roles as reducing and stabilizing agents in the overall template synthesis of tumor cell-targeted AuNPs. The AuNPs capped with WSCS and WSCS-DOTA-BBN exhibited average Au-core diameter of 17 ± 8 nm and 20 ± 7 nm with hydrodynamic diameters of 56 ± 1 and 67± 2 nm, respectively. The AuNPs-WSCS-DOTA-BBN showed optimum in vitro stability in biologically relevant solutions. The targeted AuNPs showed selective affinity toward GRP receptors overexpressed in prostate cancer cells (PC-3 and LNCaP).

Discussion

The AuNPs-WSCS-DOTA-BBN displayed cytotoxicity effects against PC-3 and LNCaP cancer cells, with concomitant safety toward the HAECs normal cells. The AuNPs-WSCS-DOTA-BBN showed synergistic targeting toward tumor cells with selective cytotoxicity of AuNPs towards PC-3 and LNCaP cells. Our investigations provide compelling evidence that AuNPs functionalized with WSCS-DOTA-BBN is an innovative nanomedicine approach for use in molecular imaging and therapy of GRP receptor-positive tumors. The template synthesis of AuNPs-WSCS-DOTA-BBN serves as an excellent non-radioactive surrogate for the development of the corresponding ¹⁹⁸AuNPs theragnostic nanoradiopharmaceutical for use in cancer diagnosis and therapy.

Photothermally Modulatable and Structurally Disintegratable Sub-8-nm Au1Ag9 Embedded Nanoblocks for Combination Cancer Therapy Produced by Plug-in Assembly

As well as the exploration of translatable delivery nanosystems for cancer therapeutic agents, the development of automatable continuous-flow manufacturing technology comprising digitally controlled reactions for the on-demand production of pharmaceuticals is an important challenge in anticancer nanomedicine. Most attempts to resolve these issues have involved the development of alternative reactions, formulations, or constructs containing stimulus components aimed at producing multiple approaches for highly efficacious combination cancer therapies. However, there has been no report of a platform based on plug-in execution that enables continuous-flow manufacture in a compact, reconfigurable manner, although an optimal platform technology may be a prerequisite for the timely translation of recently developed nanomedicines. To this end, we describe the development of a platform toward digitizable, continuous manufacture by a serial combination of plug-in reactionwares (heating plates, a spraying cup, and a photochamber) for single-pass flow fabrication. Specifically, we fabricated three different composite nanoblocks consisting of Au₁Ag₉ (<8 nm; stimulus component), docetaxel (an anticancer drug), and bovine serum albumin (a protective and targeting agent) using our system, with the result of producing nanoblocks with photothermally modulatable and structurally disintegratable properties. These were examined for effectiveness in near-infrared-induced chemothermal cancer therapy and renal excretion of Au₁Ag₉ particles and exhibited high anticancer efficacy and warrantable biosafety.

Gold nanospheres and nanorods for anti-cancer therapy: comparative studies of fabrication, surface-decoration, and anti-cancer treatments

Various gold nanoparticles have been explored as cancer therapeutics because they can be widely engineered for use as efficient drug carriers and diagnostic agents, and in photo-irradiation therapy. In the current review, we focused on shape-dependent biomedical applications of gold nanoparticles including gold nanospheres and nanorods. Fabrication and functionalization strategies of two different gold nanoparticles for anti-cancer therapy are introduced and the distinguishing performance depending on the shape is discussed to suggest the best carrier shape for specific applications. Moreover, recent advances in anti-cancer immunotherapy using gold nano-carriers are discussed. Thus, this comparative review can be helpful in deciding on suitable shapes and surface-modification strategies for preparing various gold nanoparticle-based therapeutics in anti-cancer therapy.

Insights into Characterization Methods and Biomedical Applications of Nanoparticle-Protein Corona

Nanoparticles (NPs) exposed to a biological milieu will strongly interact with proteins, forming "coronas" on the surfaces of the NPs. The protein coronas (PCs) affect the properties of the NPs and provide a new biological identity to the particles in the biological environment. The characterization of NP-PC complexes has attracted enormous research attention, owing to the crucial effects of the properties of an NP-PC on its interactions with living systems, as well as the diverse applications of NP-PC complexes. The analysis of NP-PC complexes without a well-considered approach will inevitably lead to misunderstandings and inappropriate applications of NPs. This review introduces methods for the characterization of NP-PC complexes and investigates their recent applications in biomedicine. Furthermore, the review evaluates these characterization methods based on comprehensive critical views and provides future perspectives regarding the applications of NP-PC complexes.

Acid-Responsive and Biologically Degradable Polyphosphazene Nanodrugs for Efficient Drug Delivery

To enhance the therapeutic effects and reduce the damage to normal tissues in cancer chemotherapy, it is indispensable to develop drug delivery carriers with controllable release and good biocompatibility. In this work, acid-responsive and degradable polyphosphazene (PPZ) nanoparticles were synthesized by the reaction of hexachlorotripolyphosphonitrile (HCCP) with 4-hydroxy-benzoic acid (4-hydroxy-benzylidene)-hydrazide (HBHBH) and anticancer drug doxorubicin (DOX). The controlled release of DOX could be realized based on the acid responsiveness of acylhydrazone in HBHBH. Experimental results showed that polyphosphazene nanoparticles remained stable in the body's normal fluids (pH ∼ 7.4), while they were degraded and controllable release of DOX in an acidic environment such as tumors (pH ∼ 6.8) and lysosome and endosome (∼5.0) in cancer cells In particular, the doxorubicin (DOX)-loading ratio was fair high and could be tuned from 10.6 to 52.6% by changing the dosing ratio of DOX to HBHBH. Meanwhile, the polyphosphazene nanodrugs showed excellent toxicity to tumor cells and reduced the side effect to normal cells both in vitro and in vivo due to their enhanced permeability and retention (EPR) effect and pH-sensitive degradation properties. Therefore, the constructed pH-sensitive drug delivery system has great potential for cancer chemotherapy.

Protein assembled nano-vehicle entrapping photosensitizer molecules for efficient lung carcinoma therapy

The efficiency of drug depends not only on its potency but also on its ability to reach the target sites in preference to non-target sites. In this regard, protein assembled nanocarrier is the most promising strategy for intracellular anti-cancer drug delivery. The key motive of this study is to fabricate biocompatible protein assembled nanocarrier conjugated photosensitizer system for stimuli-responsive treatment of lung carcinoma. Here, we have synthesized a unique nanohybrid of protein assembled gold nanoparticles (AuNPs), attaching a model photosensitizer, Protoporphyrin IX (PpIX) to the protein shell of the nanoparticles (NPs) imparting an ideal drug-carrier nature. Photo-induced alteration in hydrodynamic diameter suggests structural perturbation of the nanohybrid which in terms signifies on-demand drug delivery. The drug release profile has been further confirmed by using steady-state fluorescence experiments. AuNP-PpIX showed excellent anti-cancer efficiency upon green light irradiation on lung adenocarcinoma cell line (A549) through intracellular reactive oxygen species (ROS) generation. The cellular morphological changes upon PDT and internalization of nanohybrid were monitored using confocal laser scanning microscope. This anti-cancer effect of nanohybrid was associated with apoptotic pathway which was confirmed in the flow cytometric platform. The developed nanomedicine is expected to find relevance in clinical anti-cancer PDT models in the near future.

Spontaneous and instant formation of highly stable protein-nanoparticle supraparticle co-assemblies driven by hydrophobic interaction

Recently, supraparticle protein-nanoparticle co-assemblies (or 'supraparticle co-assemblies' for short) have attracted considerable interest due to their fundamental and technological value. However, it remains challenging to form supraparticle co-assemblies with high stability. Here, we show that using hydrophobic interaction, instead of the previously used electrostatic and van der Waals interactions, as the primary driving force can lead to instant formation of exceptionally stable supraparticle co-assemblies with minimal external energy input. Our formation method of supraparticle co-assemblies simply involves mixing globular proteins (e.g., bovine serum albumin) with hydrophobic nanoparticles (e.g., hydrophobic magnetic nanoparticles and hydrophobic quantum dots) without significant energy input (e.g., sonication or stirring). Upon mixing of hydrophobic nanoparticles and proteins, the formation of supraparticle co-assemblies only takes <1 minute. Further incubation of the mixture for several hours results in a gradual increase of the size uniformity of supraparticle co-assemblies. The formed supraparticle co-assemblies have been colloidally stable for 6 months and counting, and can withstand harsh environments such as basic and acidic pH, high temperature, high dilution, and serum. Co-encapsulation of different sizes/types of nanoparticles is found to be feasible and the co-encapsulation number ratio of different nanoparticles is well-controlled by the feeding ratio. Proof-of-concept studies show the potential of the supraparticle co-assemblies for biological imaging, delivery, and modulation. The combination of very rapid formation, minimal energy consumption, highly stable products, and inexpensive raw materials of this hydrophobic interaction-driven process meets many of the main goals of 'ideal' nano-manufacturing. Thus, this process could serve as the foundation of ideal manufacturing of supraparticle co-assemblies.

Producing protein-nanoparticle co-assembly supraparticles by the interfacial instability process

Originally discovered in fundamental research of nanomaterial-biomolecule interactions, protein-nanoparticle co-assembly supraparticles (PNCAS) have become an emerging class of nanomaterials with various biological applications. We apply the interfacial instability process, which was originally reported for forming nanoparticles-encapsulated polymeric micelles, to produce PNCAS. By doing so hydrophobic nanoparticles, which are often the product formed from the upstream nanoparticle synthesis step, can be directly used as the raw materials of the production process of PNCAS. On the other hand, we take advantage of the structural features of protein molecules, in comparison with amphiphilic block copolymers, to mitigate two common problems encountered in the original interfacial instability-mediated nanoparticle encapsulation process, namely (1) poor encapsulation number control and (2) inconvenience and high cost to vary the assembly size. Additionally, we achieve semi-continuous and scalable production of PNCAS by combining the electrospray process and the interfacial instability process. We also conduct proof-of-concept studies of biological applications of the PNCAS products.

Formation and Stabilization of Gold Nanoparticles in Bovine Serum Albumin Solution

The formation and growth of gold nanoparticles (AuNPs) were investigated in pH 7 buffer solution of bovine serum albumin (BSA) at room temperature. The processes were monitored by UV-Vis, circular dichroism, Raman and electron paramagnetic resonance (EPR) spectroscopies. TEM microscopy and dynamic light scattering (DLS) measurements were used to evidence changes in particle size during nanoparticle formation and growth. The formation of AuNPs at pH 7 in the absence of BSA was not observed, which proves that the albumin is involved in the first step of Au(III) reduction. Changes in the EPR spectral features of two spin probes, CAT16 and DIS3, with affinity for BSA and AuNPs, respectively, allowed us to monitor the particle growth and to demonstrate the protective role of BSA for AuNPs. The size of AuNPs formed in BSA solution increases slowly with time, resulting in nanoparticles of different morphologies, as revealed by TEM. Raman spectra of BSA indicate the interaction of albumin with AuNPs through sulfur-containing amino acid residues. This study shows that albumins act as both reducing agents and protective corona of AuNPs.

Comprehensive spectroscopic studies of synergism between Gadong starch based carbon dots and bovine serum albumin

Carbon dots (C-dots) were used to study the binding mechanisms with serum protein, bovine serum albumin (BSA) by using two notable binding systems known as non-covalent and covalent interaction. Interaction between C-dots and BSA were estimated by Stern-Volmer equation and Double Log Regression Model (DLRM). According to the fluorescent intensity, quenching of model carrier protein by C-dots was due to dynamic quenching for non-covalent and static quenching for covalent binding. The binding site constant, K_A and number of binding site, for covalent interaction is 1754.7L/mol and n≈1 (0.6922) were determined by DLRM on fluorescence quenching results. The blue shift of the fluorescence spectrum, from 450nm to 421nm (non-covalent) and 430nm (covalent) and suggested that both the microenvironment of C-dots and protein changed in relation to the protein concentration. The fluorescence intensity results show that protein structure has a significant role in Protein-C-dots interactions and type of binding influence physicochemical properties of C-dots differently. Understanding to this bio interface is important to utilize both quantum dots and biomolecules for biomedical field. It can be a useful guideline to design further applications in biomedical and bioimaging.

Protein delivery into cells using inorganic nanoparticle-protein supramolecular assemblies

The delivery of proteins into cells is a potential game changer for a wide array of therapeutic purposes, including cancer therapy, immunomodulation and treatment of inherited diseases. In this review, we present recently developed nanoassemblies for protein delivery that utilize strategies that range from direct assembly, encapsulation and composite formation. We will discuss factors that affect the efficacy of nanoassemblies for delivery from the perspective of both nanoparticles and proteins. Challenges in the field, particularly achieving effective cytosolar protein delivery through endosomal escape or evasion are discussed.

Engineered Cellular Uptake and Controlled Drug Delivery Using Two Dimensional Nanoparticle and Polymer for Cancer Treatment

Two major problems in chemotherapy, poor bioavailability of hydrophobic anticancer drug and its adverse side effects causing nausea, are taken into account by developing a sustained drug release vehicle along with enhanced bioavailability using two-dimensional layered double hydroxides (LDHs) with appropriate surface charge and its subsequent embedment in polymer matrix. A model hydrophobic anticancer drug, raloxifene hydrochloride (RH), is intercalated into a series of zinc iron LDHs with varying anion charge densities using an ion exchange technique. To achieve significant sustained delivery, drug-intercalated LDH is embedded in poly(ε-caprolactone) (PCL) matrix to develop intravenous administration and to improve the therapeutic index of the drug. The cause of sustained release is visualized from the strong interaction between LDH and drug, as measured through spectroscopic techniques, like X-ray photoelectron spectroscopy, infrared, UV-visible spectroscopy, and thermal measurement (depression of melting temperature and considerable reduction in heat of fusion), using differential scanning calorimeter, followed by delayed diffusion of drug from polymer matrix. Interestingly, polymer nanohybrid exhibits long-term and excellent in vitro antitumor efficacy as opposed to pure drug or drug-intercalated LDH or only drug embedded PCL (conventional drug delivery vehicle) as evident from cell viability and cell adhesion experiments prompting a model depicting greater killing efficiency (cellular uptake) of the delivery vehicle (polymer nanohybrid) controlled by its better cell adhesion as noticed through cellular uptake after tagging of fluorescence rhodamine B separately to drug and LDH. In vivo studies also confirm the sustained release of drug in the bloodstream of albino rats using polymer nanohybrid (novel drug delivery vehicle) along with a healthy liver vis-à-vis burst release using pure drug/drug-intercalated LDHs with considerable damaged liver.

Facile encapsulation of hydroxycamptothecin nanocrystals into zein-based nanocomplexes for active targeting in drug delivery and cell imaging

Nano-drug delivery systems that integrate inorganic and organic or even bioactive components into a single nanoscale platform are playing a hugely important role in cancer treatment. In this article, the fabrication of a versatile nanocarrier based on self-assembled structures of gold nanoparticles (AuNPs)-zein is reported, which displays high drug-loading efficiency for needle-shaped hydroxycamptothecin (HCPT) nanocrystals. The surface modification with folate-conjugated polydopamine (PFA) renders them stable and also facilitates their selective cellular internalization and enhancement of endocytosis. The release of payloads from nanocomplexes (NCs) was shown to be limited at physiological pH (17.1±2.8%) but significantly elevated at endosomal/lysosomal pH (58.4±3.0%) and at enzymatic environment (81.4±4.2%). Compared to free HCPT and its non-targeting equivalent, HCPT@AuNPs-Zein-PFA exerted a superior tumor suppression capacity as well as low side effects due to its active and passive targeting delivery both in vitro and in vivo. These results suggest that the NCs with well-defined core@shell nanostructures encapsulated with HCPT nanocrystals hold great promise to improve cancer therapy with high efficiency in the clinic.

STATEMENT OF SIGNIFICANCE

A novel nanocomplex with HCPT nanocrystals encapsulated was designed to achieve selective cellular uptake by endocytosis, acid responsive release in the tumor microenvironment and excellent tumor suppression without toxicity. This nanocomplex with conjugation of folate was stable in the bloodstream, with minimal drug release in extracellular conditions, leading to prolonged blood circulation and high accumulation in tumor tissues. The entrapment of a nanocrystal drug into nanomaterials might be capable of delivering drugs in a predictable and controllable manner.

Strategies for Preparing Albumin-based Nanoparticles for Multifunctional Bioimaging and Drug Delivery

Biosafety is the primary concern in clinical translation of nanomedicine. As an intrinsic ingredient of human blood without immunogenicity and encouraged by its successful clinical application in Abraxane, albumin has been regarded as a promising material to produce nanoparticles for bioimaging and drug delivery. The strategies for synthesizing albumin-based nanoparticles could be generally categorized into five classes: template, nanocarrier, scaffold, stabilizer and albumin-polymer conjugate. This review introduces approaches utilizing albumin in the preparation of nanoparticles and thereby provides scientists with knowledge of goal-driven design on albumin-based nanomedicine.

Protein-Based Multifunctional Nanocarriers for Imaging, Photothermal Therapy, and Anticancer Drug Delivery

We report a simple approach for fabricating plasmonic and magneto-luminescent multifunctional nanocarriers (MFNCs) by assembling gold nanorods, iron oxide nanoparticles, and gold nanoclusters within BSA nanoparticles. The MFNCs showed self-tracking capability through single- and two-photon imaging, and the potential for magnetic targeting in vitro. Appreciable T₂-relaxivity exhibited by the MFNCs indicated favorable conditions for magnetic resonance imaging. In addition to successful plasmonic-photothermal therapy of cancer cells (HeLa) in vitro, the MFNCs demonstrated efficient loading and delivery of doxorubicin to HeLa cells leading to significant cell death. The present MFNCs with their multimodal imaging and therapeutic capabilities could be eminent candidates for cancer theranostics.

A supramolecular material for dual-modal imaging and targeted cancer therapy

Recently, how to design a formulation system with simultaneous diagnosis and therapy toward cancer has attracted tremendous attention. Herein, a supramolecular material was prepared via a facile method by the co-intercalation of folic acid (FA) and doxorubicin (DOX) into the gallery of Gd³⁺-doped layered double hydroxides (LDHs), followed by surface adsorption of fluorescein isothiocyanate (FITC). This supramolecular agent was proved to exhibit excellent magnetic resonance imaging (MRI) and fluorescence imaging (FI) behavior, as well as chemotherapy toward cancer (KB cell). The co-intercalated FA enables an efficient and selective drug delivery with good specificity. This work provides a facile approach for the fabrication of a drug formulation with dual-modal imaging and targeted therapy, which could be potentially used in the practical chemotherapy and medical imaging.

An Intermittent Model for Intracellular Motions of Gold Nanostars by k-Space Scattering Image Correlation

Anisotropic metallic nanoparticles have been devised as powerful potential tools for in vivo imaging, photothermal therapy, and drug delivery thanks to plasmon-enhanced absorption and scattering cross sections, ease in synthesis and functionalization, and controlled cytotoxicity. The rational design of all these applications requires the characterization of the nanoparticles intracellular trafficking pathways. In this work, we exploit live-cell time-lapse confocal reflectance microscopy and image correlation in both direct and reciprocal space to investigate the intracellular transport of branched gold nanostars (GNSs). Different transport mechanisms, spanning from pure Brownian diffusion to (sub-)ballistic superdiffusion, are revealed by temporal and spatio-temporal image correlation spectroscopy on the tens-of-seconds timescale. According to these findings, combined with numerical simulations and with a Bayesian (hidden Markov model-based) analysis of single particle tracking data, we ascribe the superdiffusive, subballistic behavior characterizing the GNSs dynamics to a two-state switching between Brownian diffusion in the cytoplasm and molecular motor-mediated active transport. For the investigation of intermittent-type transport phenomena, we derive an analytical theoretical framework for Fourier-space image correlation spectroscopy (kICS). At first, we evaluate the influence of all the dynamic and kinetic parameters (the diffusion coefficient, the drift velocity, and the transition rates between the diffusive and the active transport regimes) on simulated kICS correlation functions. Then we outline a protocol for data analysis and employ it to derive whole-cell maps for each parameter underlying the GNSs intracellular dynamics. Capable of identifying even simpler transport phenomena, whether purely diffusive or ballistic, our intermittent kICS approach allows an exhaustive investigation of the dynamics of GNSs and biological macromolecules.

The effect of temperature on the aggregation kinetics of partially bare gold nanoparticles

Temperature dependent aggregation reaction of partially bare gold nanoparticles showed a first order kinetics and prevalence of reaction limited colloidal aggregation with an activation energy equal to 36.2 ± 3.0 kJ mol⁻¹.

Enhancing Cellular Uptake and Doxorubicin Delivery of Mesoporous Silica Nanoparticles via Surface Functionalization: Effects of Serum

In this study, we demonstrate how functional groups on the surface of mesoporous silica nanoparticles (MSNPs) can influence the encapsulation and release of the anticancer drug doxorubicin, as well as cancer cell response in the absence or presence of serum proteins. To this end, we synthesized four differently functionalized MSNPs with amine, sulfonate, polyethylene glycol, or polyethylene imine functional surface groups, as well as one type of antibody-conjugated MSNP for specific cellular targeting, and we characterized these MSNPs regarding their physicochemical properties, colloidal stability in physiological media, and uptake and release of doxorubicin in vitro. Then, the MSNPs were investigated for their cytotoxic potential on cancer cells. Cationic MSNPs could not be loaded with doxorubicin and did therefore not show any cytotoxic and antiproliferative potential on osteosarcoma cells, although they were efficiently taken up into the cells in the presence or absence of serum. In contrast, substantial amounts of doxorubicin were loaded into negatively charged and unfunctionalized MSNPs. Especially, sulfonate-functionalized doxorubicin-loaded MSNPs were efficiently taken up into the cells in the presence of serum and showed an accelerated toxic and antiproliferative potential compared to unfunctionalized MSNPs, antibody-conjugated MSNPs, and even free doxorubicin. These findings stress the high importance of the surface charge as well as of the protein corona for designing and applying nanoparticles for targeted drug delivery.

Theranostic potential of gold nanoparticle-protein agglomerates

Owing to the ever-increasing applications, glittered with astonishing success of gold nanoparticles (Au NPs) in biomedical research as diagnostic and therapeutic agents, the study of Au NP-protein interaction seems critical for maximizing their theranostic efficiency, and thus demands comprehensive understanding. The mutual interaction of Au NPs and proteins at physiological conditions may result in the aggregation of protein, which can ultimately lead to the formation of Au NP-protein agglomerates. In the present article, we try to appreciate the plausible steps involved in the Au NP-induced aggregation of proteins and also the importance of the proteins' three-dimensional structures in the process. The Au NP-protein agglomerates can potentially be exploited for efficient loading and subsequent release of various therapeutically important molecules, including anticancer drugs, with the unique opportunity of incorporating hydrophilic as well as hydrophobic drugs in the same nanocarrier system. Moreover, the Au NP-protein agglomerates can act as 'self-diagnostic' systems, allowing investigation of the conformational state of the associated protein(s) as well as the protein-protein or protein-Au NP interaction within the agglomerates. Furthermore, the potential of these Au NP-protein agglomerates as a novel platform for multifunctional theranostic application along with exciting future-possibilities is highlighted here.

Utilizing the protein corona around silica nanoparticles for dual drug loading and release

A protein corona forms spontaneously around silica nanoparticles (SNPs) in serum-containing media. To test whether this protein corona can be utilized for the loading and release of anticancer drugs we incorporated the hydrophilic doxorubicin, the hydrophobic meloxicam as well as their combination in the corona around SNPs. The application of corona-covered SNPs to osteosarcoma cells revealed that drug-free particles did not affect the cell viability. In contrast, SNPs carrying a protein corona with doxorubicin or meloxicam lowered the cell proliferation in a concentration-dependent manner. In addition, these particles had an even greater antiproliferative potential than the respective concentrations of free drugs. The best antiproliferative effects were observed for SNPs containing both doxorubicin and meloxicam in their corona. Co-localization studies revealed the presence of doxorubicin fluorescence in the nucleus and lysosomes of cells exposed to doxorubicin-containing coated SNPs, suggesting that endocytotic uptake of the SNPs facilitates the cellular accumulation of the drug. Our data demonstrate that the protein corona, which spontaneously forms around nanoparticles, can be efficiently exploited for loading the particles with multiple drugs for therapeutic purposes. As drugs are efficiently released from such particles they may have a great potential for nanomedical applications.

Gold Nanocluster Embedded Albumin Nanoparticles for Two-Photon Imaging of Cancer Cells Accompanying Drug Delivery

Gold nanoclusters in albumin nanoparticles (nanovehicles) are used for single-photon and two-photon imaging of cancer cells following the delivery of doxorubicin through the nanovehicle. NIR excitation and emission wavelengths in the biological window (650-900 nm) make the nanovehicle an ideal potential platform for imaging guided drug delivery.

Cu2+-embedded carbon nanoparticles as anticancer agents

We report the synthesis of luminescent carbon nanoparticles (93 ± 50 nm) embedded with Cu²⁺. It was observed that at a relatively low concentration of Cu²⁺ (2.55 ppm), cervical cancer HeLa cells died due to apoptosis induced by the nanoparticles. Also, generation of reactive oxygen species in the cells, in the presence of the composite nanoparticles, has been attributed to their killing. The luminescence of the carbon nanoparticles was used for imaging of the cells.

Controlling the self-assembly and optical properties of gold nanoclusters and gold nanoparticles biomineralized with bovine serum albumin

While the size-dependent optical properties of BSA-stabilized gold nanoclusters are well known, the time-dependent growth mechanism remains to be described.

Facile preparation of albumin-stabilized gold nanostars for the targeted photothermal ablation of cancer cells

BSA–FA conjugation was used as a stabilizer to synthesize gold nanostars (BSA–FA–AuNSs). The prepared BSA–FA–AuNSs should have a great potential as photothermal conversion agents for the receptor-mediated treatment of cancer cells.

Laser-assisted synthesis of multi-colored protein dots and their biological distribution in experimental mice using a dye tracking method

We report a novel method for the synthesis of ultra-bright green and red colored protein dots (Pr-dots) using continuous and pulse lasers (λ = 534 and 1064 nm) with lysozyme as a precursor in ethanol.

Green synthesis of pullulan stabilized gold nanoparticles for cancer targeted drug delivery

The aim of this study was to synthesize green chemistry based gold nanoparticles using liver specific biopolymer and to develop a liver cancer targeted drug delivery system with enhanced efficacy and minimal side effects. Pullulan stabilized gold nanoparticles (PAuNPs) were coupled with 5-Fluorouracil (5-Fu) and folic acid (Fa) which could be used as a tool for targeted drug delivery and imaging of cancer. The toxicity of 5-Fu, 5-Fu adsorbed gold nanoparticles (5-Fu@AuNPs), Fa-coupled 5-Fu adsorbed gold nanoparticles (5-Fu@AuNPs-Fa), was studied using zebrafish embryo as an in vivo model. The in vitro cytotoxicity of free 5-Fu, 5-Fu@AuNPs, 5-Fu@AuNPs-Fa against HepG2 cells was studied and found that the amount of 5-Fu required to achieve 50% of growth of inhibition (Ic50) was much lower in 5-Fu@AuNP-Fa than in free 5-Fu, 5-Fu@AuNPs. The in vivo biodistribution of PAuNPs showed that higher amount of gold had been accumulated in liver (54.42±5.96 μg) than in other organs.

Morphological effect of gold nanoparticles on the adsorption of bovine serum albumin

The role of morphology and surface chemistry of gold nanoparticles in the adsorption of bovine serum albumin.

Swarming carbon dots for folic acid mediated delivery of doxorubicin and biological imaging

Carbon dots (C-dots) are one of the most highlighted carbon-based materials for biological applications such as delivery of therapeutic payloads for cancer treatment mainly due to their biocompatibility and unique optical properties. In this work, we have explored the drug carrying capacity of highly fluorescent sorbitol-derived C-dots for targeted delivery of doxorubicin (DOX). We have used folic acid (FA) as a navigational molecule due to its high expression in most cancer cells. Before attachment of the DOX, the surfaces of the C-dots were protected with bovine serum albumin (BSA) to make them more biocompatible and able to hold a high amount of drugs. The release profile of DOX was studied using standard statistical models and confirmed to be first order at pH 7.2. Cellular imaging was performed using epifluorescence microscopy, which showed bright green coloured fluorescence due to internalization of C-dots specifically targeted with FA in HeLa cells.