Exploiting the protein corona around gold nanorods for low-dose combined photothermal and photodynamic therapy

Nature-inspired protein mineralization strategies for nanoparticle construction: advancing effective cancer therapy

Recently, nanotechnology has shown great potential in the field of cancer therapy due to its ability to improve the stability and solubility and reduce side effects of drugs. The biomimetic mineralization strategy based on natural proteins and metal ions provides an innovative approach for the synthesis of nanoparticles. This strategy utilizes the unique properties of natural proteins and the mineralization ability of metal ions to combine nanoparticles through biomimetic mineralization processes, achieving the effective treatment of tumors. The precise control of the mineralization process between proteins and metal ions makes it possible to obtain nanoparticles with the ideal size, shape, and surface characteristics, thereby enhancing their stability and targeting ability in vivo. Herein, initially, we analyze the role of protein molecules in biomineralization and comprehensively review the functions, properties, and applications of various common proteins and metal particles. Subsequently, we systematically review and summarize the application directions of nanoparticles synthesized based on protein biomineralization in tumor treatment. Specifically, we discuss their use as efficient drug delivery carriers and role in mediating monotherapy and synergistic therapy using multiple modes. Also, we specifically review the application of nanomedicine constructed through biomimetic mineralization strategies using natural proteins and metal ions in improving the efficiency of tumor immunotherapy.

Dual-functional nano-photosensitizers: Eosin-Y decorated gold nanorods for plasmon-enhanced fluorescence and singlet oxygen generation

Photosensitizer (PS) with enhanced fluorescence is attractive for image-guided photodynamic therapy (PDT) due to its dual functional role in Singlet Oxygen Generation (SOG) and producing high fluorescence signals. Here, Eosin-Y (Ey) decorated polymer coated gold nanorods (GNRs) of different aspect ratios are synthesized and introduced as novel plasmon-enhanced nano-photosensitizers for this purpose. We show, upon excitation at 519 nm, simultaneous enhancement in fluorescence and SOG was achieved for the hybrid nanostructure. The best enhancement factors of 110 and 18 for metal-enhanced fluorescence and metal-enhanced SOG, respectively, are obtained with GNRs of length 133 nm and width 45 nm, where Ey is positioned at 12.6 nm from the metal core using layer-by-layer assembly of oppositely charged polymers. The observed plasmonic effect is critically analysed by comparing the near field damping rate along with decay length, far field scattering and nonradiative energy transfer of the nanohybrids.

Biomolecular Corona of Gold Nanoparticles: The Urgent Need for Strong Roots to Grow Strong Branches

Gold nanoparticles (GNPs) are largely employed in diagnostics/biosensors and are among the most investigated nanomaterials in biology/medicine. However, few GNP-based nanoformulations have received FDA approval to date, and promising in vitro studies have failed to translate to in vivo efficacy. One key factor is that biological fluids contain high concentrations of proteins, lipids, sugars, and metabolites, which can adsorb/interact with the GNP's surface, forming a layer called biomolecular corona (BMC). The BMC can mask prepared functionalities and target moieties, creating new surface chemistry and determining GNPs' biological fate. Here, the current knowledge is summarized on GNP-BMCs, analyzing the factors driving these interactions and the biological consequences. A partial fingerprint of GNP-BMC analyzing common patterns of composition in the literature is extrapolated. However, a red flag is also risen concerning the current lack of data availability and regulated form of knowledge on BMC. Nanomedicine is still in its infancy, and relying on recently developed analytical and informatic tools offers an unprecedented opportunity to make a leap forward. However, a restart through robust shared protocols and data sharing is necessary to obtain "stronger roots". This will create a path to exploiting BMC for human benefit, promoting the clinical translation of biomedical nanotools.

Present and future of metal nanoparticles in tumor ablation therapy

Cancer is an important factor affecting the quality of human life as well as causing death. Tumor ablation therapy is a minimally invasive local treatment modality with unique advantages in treating tumors that are difficult to remove surgically. However, due to its physical and chemical characteristics and the limitation of equipment technology, ablation therapy cannot completely kill all tumor tissues and cells at one time; moreover, it inevitably damages some normal tissues in the surrounding area during the ablation process. Therefore, this technology cannot be the first-line treatment for tumors at present. Metal nanoparticles themselves have good thermal and electrical conductivity and unique optical and magnetic properties. The combination of metal nanoparticles with tumor ablation technology, on the one hand, can enhance the killing and inhibiting effect of ablation technology on tumors by expanding the ablation range; on the other hand, the ablation technology changes the physicochemical microenvironment such as temperature, electric field, optics, oxygen content and pH in tumor tissues. It helps to stimulate the degree of local drug release of nanoparticles and increase the local content of anti-tumor drugs, thus forming a synergistic therapeutic effect with tumor ablation. Recent studies have found that some specific ablation methods will stimulate the body's immune response while physically killing tumor tissues, generating a large number of immune cells to cause secondary killing of tumor tissues and cells, and with the assistance of metal nanoparticles loaded with immune drugs, the effect of this anti-tumor immunotherapy can be further enhanced. Therefore, the combination of metal nanoparticles and ablative therapy has broad research potential. This review covers common metallic nanoparticles used for ablative therapy and discusses in detail their characteristics, mechanisms of action, potential challenges, and prospects in the field of ablation.

Role of the Human Serum Albumin Protein Corona in the Antimicrobial and Photothermal Activity of Metallic Nanoparticles against Escherichia coli Bacteria

The emergence of antibiotic-resistant bacteria has become a major public health concern, leading to growing interest in alternative antimicrobial agents. The antibacterial activity of metal nanoparticles (NPs) has been extensively studied, showing that they can effectively inhibit the growth of various bacteria, including both Gram-positive and -negative strains. The presence of a protein corona, formed by the adsorption of proteins onto the NP surface in biological fluids, can significantly affect their toxicity. Understanding the effect of the protein corona on the antimicrobial activity of metal NPs is crucial for their effective use as antimicrobial agents. In this study, the antimicrobial activity of noble metal NPs, such as platinum (Pt), silver (Ag), and gold (Au) with and without the human serum albumin (HSA) protein corona against Escherichia coli strains, was investigated. In addition, the plasmonic photothermal effect related to AuNPs, which resulted to be the most biocompatible compared to the other considered metals, was evaluated. The obtained results suggest that the HSA protein corona modulated the antimicrobial activity exerted by the metal NPs against E. coli bacteria. These findings may pave the way for the investigation and development of innovative nanoapproaches to face antibiotic resistance emergence.

Investigation of thymine as a potential cancer biomarker employing tryptophan with nanomaterials as a biosensor

Tryptophan and tryptophan-based nanomaterials sensors in a solution have been developed to directly evaluate thymine. The determination of thymine has been done via quenching of the fluorescence of tryptophan and tryptophan-based nanomaterials such as graphene (Gr), graphene oxide (GO), gold nanoparticles (AuNPs), gold-silver nanocomposite (Au-Ag NC) in a physiological buffer. As the concentration of thymine rises, the fluorescence of tryptophan and tryptophan/nanomaterials becomes less intense. Trp, Trp/Gr, and tryptophan/(Au-Ag) NC systems' quenching mechanisms were dynamic, but tryptophan /GO and tryptophan/AuNPs' quenching mechanisms were static. The linear dynamic range for the determination of thy by tryptophan and tryptophan /nanomaterials is 10 to 200 μM. The detection limits for tryptophan, tryptophan /Gr, tryptophan /GO, tryptophan /AuNPs, and tryptophan/Au-Ag NC were 3.21, 14.20, 6.35, 4.67and 7.79 Μm, respectively. Thermodynamic parameters for the interaction of the Probes with Thy include the enthalpy (H°) and entropy (S°) change values, were assessed, as well as the binding constant (Ka) of Thy with Trp and Trp-based nanomaterials. A recovery study was conducted utilizing a human serum sample after the addition of the required quantity of the investigational thymine.

Recent advances in surface modification of micro- and nano-scale biomaterials with biological membranes and biomolecules

Surface modification of biomaterial can improve its biocompatibility and add new biofunctions, such as targeting specific tissues, communication with cells, and modulation of intracellular trafficking. Here, we summarize the use of various natural materials, namely, cell membrane, exosomes, proteins, peptides, lipids, fatty acids, and polysaccharides as coating materials on micron- and nano-sized particles and droplets with the functions imparted by coating with different materials. We discuss the applicability, operational parameters, and limitation of different coating techniques, from the more conventional approaches such as extrusion and sonication to the latest innovation seen on the microfluidics platform. Methods commonly used in the field to examine the coating, including its composition, physical dimension, stability, fluidity, permeability, and biological functions, are reviewed.

Progress of Nanomaterials-Based Photothermal Therapy for Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is one of the top 15 most prevalent cancers worldwide. However, the current treatment models for OSCC (e.g., surgery, chemotherapy, radiotherapy, and combination therapy) present several limitations: damage to adjacent healthy tissue, possible recurrence, low efficiency, and severe side effects. In this context, nanomaterial-based photothermal therapy (PTT) has attracted extensive research attention. This paper reviews the latest progress in the application of biological nanomaterials for PTT in OSCC. We divide photothermal nanomaterials into four categories (noble metal nanomaterials, carbon-based nanomaterials, metal compounds, and organic nanomaterials) and introduce each category in detail. We also mention in detail the drug delivery systems for PTT of OSCC and briefly summarize the applications of hydrogels, liposomes, and micelles. Finally, we note the challenges faced by the clinical application of PTT nanomaterials and the possibility of further improvement, providing direction for the future research of PTT in OSCC treatment.

Gold nanocrystals: optical properties, fine-tuning of the shape, and biomedical applications

Noble metal nanomaterials with special physical and chemical properties have attracted considerable attention in the past decades. In particular, Au nanocrystals (NCs), which possess high chemical inertness and unique surface plasmon resonance (SPR), have attracted extensive research interest. In this study, we review the properties and preparation of Au NCs with different morphologies as well as their important applications in biological detection. The preparation of Au NCs with different shapes by many methods such as seed-mediated growth method, seedless synthesis, polyol process, ultrasonic method, and hydrothermal treatment has already been introduced. In the seed-mediated growth method, the influence factors in determining the final shape of Au NCs are discussed. Au NCs, which show significant size-dependent color differences are proposed for preparing biological probes to detect biomacromolecules such as DNA and protein, while probe conjugate molecules serves as unique coupling agents with a target. Particularly, Au nanorods (NRs) have some unique advantages in the application of biological probes and photothermal cancer therapy compared to Au nanoparticles (NPs).

Recent advances in biological applications of nanomaterials through defect engineering

In recent years, defect engineering sprung up in the artificial nanomaterials (NMs) has attracted significant attention, since the physical and chemical properties of NMs could be largely optimized based on the rational control of different defect types and densities. Defective NMs equipped with the improved electric and catalytic ability, would be widely utilized as the photoelectric device and catalysts to alleviate the growing demands of industrial production and environmental treatments. In particular, considering that the features of targeting, adsorptive, loading and optical could be adjusted by the introduction of defects, numerous defective NMs are encouraged to be applied in the biological fields including bacterial inactivation, cancer therapy and so on. And this review is devoted to summarize the recent biological applications of NMs with abundant defects. Moreover, the opportunity of these defective NMs released into the surrounding environment continue to increase, the direct and indirect contact with biological molecules and organisms would be inevitable. Due to its high reactivity and adsorption triggered by defects, NMs tend to exhibit overestimate biological behaviors and effects on organisms. Thus, the sections regarding toxicological effects of NMs with abundant defects are also carried out to supplement the safety assessments of NMs and guide further applications in the industrial production and living.

A Review: Potential Application and Outlook of Photothermal Therapy in Oral Cancer Treatment

As one of the most common malignant tumors, oral cancer threatens people's health worldwide. However, traditional therapies, including surgery, radiotherapy, and chemotherapy can't meet the requirement of cancer cure. Photothermal therapy (PTT) has attracted widespread attentions for its advantages of the noninvasive process, few side effects, and promising tumor ablation. Up to now, three types of photothermal agents (PTAs) have been widely employed in oral cancer therapies, which involve metallic materials, carbon-based materials, and organic materials. Previous research mainly introduced hybrid materials due to benefits from the synergistic effect of multiple functions. In this review, we present the advancement of each type PTAs for oral cancer treatment in recent years. In each part, we introduce the properties and synthesis of each PTA, summarize the current studies, and analyze their potential applications. Furthermore, we discuss the status quo and the deficiencies hindering the clinical application of PTT, based on which gives the perspective of its future developing directions.

Strategy for Avoiding Protein Corona Inhibition of Targeted Drug Delivery by Linking Recombinant Affibody Scaffold to Magnetosomes

PURPOSE

Nanoparticles (NPs) decorated with functional ligands are promising candidates for cancer diagnosis and treatment. However, numerous studies have shown that chemically coupled targeting moieties on NPs lose their targeting capability in the biological milieu because they are shielded or covered by a "protein corona". Herein, we construct a functional magnetosome that recognizes and targets cancer cells even in the presence of protein corona.

METHODS

Magnetosomes (BMPs) were extracted from magnetotactic bacteria, M. gryphiswaldense (MSR-1), and decorated with trastuzumab (TZ) via affibody (RA) and glutaraldehyde (GA). The engineered BMPs are referred to as BMP-RA-TZ and BMP-GA-TZ. Their capacities to combine HER2 were detected by ELISA, the quantity of plasma corona proteins was analyzed using LC-MS. The efficiencies of targeting SK-BR-3 were demonstrated by confocal laser scanning microscopy and flow cytometry.

RESULTS

Both engineered BMPs contain up to ~0.2 mg TZ per mg of BMP, while the quantity of HER2 binding to BMP-RA-TZ is three times higher than that binding to BMP-GA-TZ. After incubation with normal human plasma or IgG-supplemented plasma, GA-TZ-containing BMPs have larger hydrated radii and more surface proteins in comparison with RA-TZ-containing BMPs. The TZ-containing BMPs all can be targeted to and internalized in the HER2-overexpressing breast cancer cell line SK-BR-3; however, their targeting efficiencies vary considerably: 50-75% for RA-TZ-containing BMPs and 9-19% for GA-TZ-containing BMPs. BMPs were incubated with plasma (100%) and cancer cells to simulate human in vivo environment. In this milieu, BMP-RA-TZ uptake efficiency of SK-BR-3 reaches nearly 80% (slightly lower than for direct interaction with BMP-RA-TZ), whereas the BMP-GA-TZ uptake efficiency is <17%.

CONCLUSION

Application of the RA scaffold promotes and orients the arrangement of targeting ligands and reduces the shielding effect of corona proteins. This strategy improves the targeting capability and drug delivery of NP in a simulated in vivo milieu.

NIR and glutathione trigger the surface release of methotrexate linked by Diels-Alder adducts to anisotropic gold nanoparticles

The administration and controlled release of drugs over time remains one of the greatest challenges of science today. In the nanomaterials field, anisotropic gold nanoparticles (AuNPs) with plasmon bands centered at the near-infrared region (NIR), such as gold nanorods (AuNRs) and gold nanoprisms (AuNPrs), under laser irradiation, locally increase the temperature, allowing the release of drugs. In this sense, temporally controlled drug delivery could be promoted by external stimuli using thermo-reversible chemical reactions, such as Diels-Alder cycloadditions from a diene and a dienophile fragment (compound a). In this study, an antitumor drug (methotrexate, MTX) was linked to plasmonic AuNPs by a Diels-Alder adduct (compound c), which after NIR suffers a retro-Diels-Alder reaction, producing release of the drug (compound b). We obtained two nanosystems based on AuNRs and AuNPrs. Both nanoconstructs were coated with BSA-r₈ (Bovine Serum Albumin functionalized with Arg₈, all-D octa arginine) in order to increase the colloidal stability and promote internalization of the nanosystems on HeLa and SK-BR-3 cells. In addition, the presence of BSA allows protecting the cargo from being released on the extracellular environment and promotes the photothermal release of the drug in the presence of glutathione (GSH). The nanosystems' drug release profile was evaluated after NIR irradiation in the presence and absence of glutathione (GSH), showing a considerable increase of drug release when NIR light and glutathione were combined. This work broadens the range of possibilities of using two complementary strategies for the controlled release of an antitumor drug from AuNRs and AuNPrs: the photothermal cleavage of a thermolabile adduct controlled by an external stimulus (laser irradiation), complemented with the use of the intracellular metabolite GSH.

Recent advances in the exonuclease III-assisted target signal amplification strategy for nucleic acid detection

The detection of nucleic acids has become significantly important in molecular diagnostics, gene therapy, mutation analysis, forensic investigations and biomedical development, and so on. In recent years, exonuclease III (Exo III) as an enzyme in the 3'-5' exonuclease family has evolved as a frequently used technique for signal amplification of low level DNA target detection. Different from the traditional target amplification strategies, the Exo III-assisted amplification strategy has been used for target DNA detection through directly amplifying the amounts of signal reagents. The Exo III-assisted amplification strategy has its unique advantages and characters, because the character of non-specific recognition of Exo III can overcome the limitation of a target-to-probe ratio of 1 : 1 in the traditional nucleic acid hybridization assay and acquire higher sensitivity. In this review, we selectively discuss the recent advances in the Exo III-assisted amplification strategy, including the amplification strategy integrated with nanomaterials, biosensors, hairpin probes and other nucleic acid detection methods. We also discuss the strengths and limitations of each strategy and methods to overcome the limitations.

Gold Nanorods: The Most Versatile Plasmonic Nanoparticles

Gold nanorods (NRs), pseudo-one-dimensional rod-shaped nanoparticles (NPs), have become one of the burgeoning materials in the recent years due to their anisotropic shape and adjustable plasmonic properties. With the continuous improvement in synthetic methods, a variety of materials have been attached around Au NRs to achieve unexpected or improved plasmonic properties and explore state-of-the-art technologies. In this review, we comprehensively summarize the latest progress on Au NRs, the most versatile anisotropic plasmonic NPs. We present a representative overview of the advances in the synthetic strategies and outline an extensive catalogue of Au-NR-based heterostructures with tailored architectures and special functionalities. The bottom-up assembly of Au NRs into preprogrammed metastructures is then discussed, as well as the design principles. We also provide a systematic elucidation of the different plasmonic properties associated with the Au-NR-based structures, followed by a discussion of the promising applications of Au NRs in various fields. We finally discuss the future research directions and challenges of Au NRs.

Simultaneous Stabilization and Functionalization of Gold Nanoparticles via Biomolecule Conjugation: Progress and Perspectives

Gold nanoparticles (AuNPs) are used in various biological applications because of their small surface area-to-volume ratios, ease of synthesis and modification, low toxicity, and unique optical properties. These properties can vary significantly with changes in AuNP size, shape, composition, and arrangement. Thus, the stabilization of AuNPs is crucial to preserve the properties required for biological applications. In recent years, various polymer-based physical and chemical methods have been extensively used for AuNP stabilization. However, a new stabilization approach using biomolecules has recently attracted considerable attention. Biomolecules such as DNA, RNA, peptides, and proteins are representative of the biomoieties that can functionalize AuNPs. According to several studies, biomolecules can stabilize AuNPs in biological media; in addition, AuNP-conjugated biomolecules can retain certain biological functions. Furthermore, the presence of biomolecules on AuNPs significantly enhances their biocompatibility. This review provides a representative overview of AuNP functionalization using various biomolecules. The strategies and mechanisms of AuNP functionalization using biomolecules are comprehensively discussed in the context of various biological fields.

Oligoarginine Peptide Conjugated to BSA Improves Cell Penetration of Gold Nanorods and Nanoprisms for Biomedical Applications

Gold nanoparticles (AuNPs) have been shown to be outstanding tools for drug delivery and biomedical applications, mainly owing to their colloidal stability, surface chemistry, and photothermal properties. The biocompatibility and stability of nanoparticles can be improved by capping the nanoparticles with endogenous proteins, such as albumin. Notably, protein coating of nanoparticles can interfere with and decrease their cell penetration. Therefore, in the present study, we functionalized albumin with the r₈ peptide (All-D, octaarginine) and used it for coating NIR-plasmonic anisotropic gold nanoparticles. Gold nanoprisms (AuNPrs) and gold nanorods (AuNRs) were coated with bovine serum albumin (BSA) previously functionalized using a cell penetrating peptide (CPP) with the r₈ sequence (BSA-r₈). The effect of the coated and r₈-functionalized AuNPs on HeLa cell viability was assessed by the MTS assay, showing a low effect on cell viability after BSA coating. Moreover, the internalization of the nanostructures into HeLa cells was assessed by confocal microscopy and transmission electron microscopy (TEM). As a result, both nanoconstructs showed an improved internalization level after being capped with BSA-r₈, in contrast to the BSA-functionalized control, suggesting the predominant role of CPP functionalization in cell internalization. Thus, our results validate both novel nanoconstructs as potential candidates to be coated by endogenous proteins and functionalized with a CPP to optimize cell internalization. In a further approach, coating AuNPs with CPP-functionalized BSA can broaden the possibilities for biomedical applications by combining their optical properties, biocompatibility, and cell-penetration abilities.

Nanomaterials and their composite scaffolds for photothermal therapy and tissue engineering applications

Photothermal therapy (PTT) has attracted broad attention as a promising method for cancer therapy with less severe side effects than conventional radiation therapy, chemotherapy and surgical resection. PTT relies on the photoconversion capacity of photothermal agents (PTAs), and a wide variety of nanomaterials have been employed as PTAs for cancer therapy due to their excellent photothermal properties. The PTAs are systematically or locally administered and become enriched in cancer cells to increase ablation efficiency. In recent years, PTAs and three-dimensional scaffolds have been hybridized to realize the local delivery of PTAs for the repeated ablation of cancer cells. Meanwhile, the composite scaffolds can stimulate the reconstruction and regeneration of the functional tissues and organs after ablation of cancer cells. A variety of composite scaffolds of photothermal nanomaterials have been prepared to combine the advantages of different modalities to maximize their therapeutic efficacy with minimal side effects. The synergistic effects make the composite scaffolds attractive for biomedical applications. This review summarizes these latest advances and discusses the future prospects.

Pectin-Coated Plasmonic Nanoparticles for Photodynamic Therapy: Inspecting the Role of Serum Proteins

Plasmonic metal nanoparticles (NPs) can be used as enhancers of the efficiency of standard photosensitizers (PSs) in photodynamic therapy (PDT). Protein corona, the adsorption layer that forms spontaneously around NPs once in contact with biological fluids, determines to a great extent the efficiency of PDT. In this work, we explore the possibility that pectin-coated Au NPs (Au@Pec NPs) could act as adjuvants in riboflavin (Rf)-based PDT by comparing the photodamage in HeLa cells cultured in the presence and in the absence of the NPs. Moreover, we investigate the impact that the preincubation of Rf and Au@Pec NPs (or Ag@Pec NPs) at two very different serum concentrations could have on cell's photodamage. Because reactive oxygen species (ROS) precursors are the excited states of the PS, the effect of proteins on the photophysics of Rf and Rf/plasmonic NPs was studied by transient absorption experiments. The beneficial effect of Au@Pec NPs in Rf-based PDT on HeLa cells cultured under standard serum conditions was demonstrated for the first time. However, the preincubation of Rf and Au@Pec NPs (or Ag@Pec NPs) with serum has undesirable results regarding the enhancement of Rf-based PDT. In this sense, we also verified that more concentrated protein conditions result in lower amounts of the triplet excited state of Rf and thus an expected lower production of ROS, which are the key elements for PDT's efficacy. These findings point out the relevance of serum concentration in the design of in vitro cell culture experiments carried out to determine the best way to combine and use potential sensitizers with plasmonic NPs to develop more effective PDTs.

Binding-Mediated Formation of Ribonucleoprotein Corona for Efficient Delivery and Control of CRISPR/Cas9

Protein coronae formed with nanoparticles confer several useful properties. However, the non-specific nature of protein corona formation makes it difficult to deliver specific proteins for therapeutic applications. Herein, we report on the construction of a new type of protein corona, termed binding-mediated protein corona. This new corona enables the efficient and controllable delivery of functional proteins, which is otherwise challenging for conventional protein coronae. We show the design and delivery of the ribonucleoprotein corona for the CRISPR/Cas9 system. Successful gene editing in human cell lines (Hela and HEK293) demonstrates the efficient delivery, high stability, low cytotoxicity, and well-controlled activity of the Cas9-guide RNA ribonucleoprotein. The binding-mediated protein corona strategy opens up new opportunities for therapeutic protein delivery.

Adsorption of bovine serum albumin on gold nanoprisms: interaction and effect of NIR irradiation on protein corona

Because of their photothermal properties, gold nanoparticles (AuNPs) have gained attention regarding their use in drug delivery and therapeutic applications. In this sense, it is interesting to consider their interactions with biologically available proteins, such as serum albumin, as well as the effects of irradiation and photothermal conversion on the protein structure that can lead to a loss of function or generate an immune response. Gold nanoprisms (AuNPrs) have gained interest due to their low toxicity, ease of synthesis, and excellent stability, promoting their use in bioapplications such as surface-enhanced Raman spectroscopy (SERS), drug delivery, and photothermal therapy. The interaction between AuNPrs, with plasmon bands centred in the near-infrared region (NIR), and bovine serum albumin (BSA) has not been explored yet. UV-Vis spectroscopy, dynamic light scattering (DLS) and fluorescence spectroscopy were used to study the interaction between AuNPrs and BSA in addition to estimation of the adsorption rate and kinetic and thermodynamic parameters (K, ΔH°, ΔG°, ΔS°, and Ea) using adsorption isotherms and Langmuir and Freundlich models. The results suggest spontaneous cooperative binding in multilayer adsorption, achieved by the chemisorption of BSA on the AuNPr surface through the S-Au interaction, as confirmed by Raman spectroscopy. On the other hand, the photothermal conversion efficiency (PE) of the coated nanoparticles after NIR irradiation was assessed, resulting in a slight decrease in the PE of BSA coated on AuNPrs in comparison with that of noncapped nanoparticles. The effect of the irradiation on the protein conformation of capped nanoparticles was also assessed; circular dichroism showed BSA unfolding upon interaction with AuNPrs, with a decrease in the α-helix and β-sheet contents, as well as an increase in random coil conformations. Changes in the Raman spectrum suggest a modification of the disposition of the protein residues exposed to the gold surface after NIR irradiation; but at the secondary structure level, no relevant changes were observed. This provides possibilities for the use of NPs-BSA for bioapplications based on the photothermal effect promoted by laser irradiation, since the biological identity of the protein is preserved after NIR irradiation.

Stealthiness and Hematocompatibility of Gold Nanoparticles with Pre-Formed Protein Corona

Studies have established that a serum protein corona pre-formed around gold nanorods (NRs) could be exploited for loading photosensitizers and chemotherapeutics to result in efficient cell kill in vitro with an extremely low dose. In this study, we further demonstrated that pre-forming a serum protein corona (PC) around citrate-capped NRs (NR-Cit) to form NR-PC conferred them stealth property and high hematocompatibility similar to the common strategy of PEGylating NRs, which would otherwise not be able to evade the immune system. Specifically, the NR-PC caused minimal complement activation with significantly lower formation of the terminal complement complex SC5b-9 measured in human serum containing NR-PC, and this resulted in low uptake by phagocytic U937 monocytes of 5.9% of the initial gold dose compared to 55.8% of NR-Cit. In addition, NR-PC exhibited very low hemolytic activity of less than 0.2% hemolysis with no observable effect on RBC morphology as opposed to 0.6% for NR-Cit at the same concentration of 1 nM NRs. Furthermore, we showed that the high hematocompatibility and stealth property of NR-PC were maintained even after the loading of small molecules, photosensitizer Chlorine e6 (Ce6), into the protein corona, thus further establishing the potential clinical relevance of exploiting the inevitably formed serum protein corona on nanoparticles as an effective delivery vector for small molecular therapeutics.

Smart materials-integrated sensor technologies for COVID-19 diagnosis

After the first case has appeared in China, the COVID-19 pandemic continues to pose an omnipresent threat to global health, affecting more than 70 million patients and leading to around 1.6 million deaths. To implement rapid and effective clinical management, early diagnosis is the mainstay. Today, real-time reverse transcriptase (RT)-PCR test is the major diagnostic practice as a gold standard method for accurate diagnosis of this disease. On the other side, serological assays are easy to be implemented for the disease screening. Considering the limitations of today's tests including lengthy assay time, cost, the need for skilled personnel, and specialized infrastructure, both strategies, however, have impediments to be applied to the resource-scarce settings. Therefore, there is an urgent need to democratize all these practices to be applicable across the globe, specifically to the locations comprising of very limited infrastructure. In this regard, sensor systems have been utilized in clinical diagnostics largely, holding great potential to have pivotal roles as an alternative or complementary options to these current tests, providing crucial fashions such as being suitable for point-of-care settings, cost-effective, and having short turnover time. In particular, the integration of smart materials into sensor technologies leverages their analytical performances, including sensitivity, linear dynamic range, and specificity. Herein, we comprehensively review major smart materials such as nanomaterials, photosensitive materials, electrically sensitive materials, their integration with sensor platforms, and applications as wearable tools within the scope of the COVID-19 diagnosis.

Light-independent M1 macrophage polarization by photosensitizer-loaded protein corona on gold nanorods

Aim: To establish a light-independent functionality of gold nanorods (AuNRs) with a human serum (HS) protein corona loaded with photosensitizer Chlorin e6 (AuNR-HS-Ce6) in M1 polarization of macrophages. Methods: RT-qPCR and ELISA were used to determine gene and protein expression, respectively. Uptake of AuNR-HS-Ce6 was determined via flow cytometry, inductively coupled plasma mass spectrometry and fluorescence microscopy. Cell viability was determined using PrestoBlue^® cell viability assay. Results: An increase in M1 gene and protein expression was observed in AuNR-HS-Ce6-treated macrophages. Delivery of high Ce6 payload via AuNR-HS-Ce6 was the primary contributor toward M1 polarization. Finally, DLD-1 cells treated with conditioned media from AuNR-HS-Ce6-treated macrophages showed significantly reduced proliferation. Conclusion: Our study suggests an immunomodulatory potential of Ce6 in inducing light-independent M1 polarization outside of its role as a photosensitizer.

Polyelectrolyte stiffness on gold nanorods mediates cell membrane damage

Charge and surface chemistry of gold nanorods (AuNRs) are often considered the predictive factors for cell membrane damage. Unfortunately, extensive research on AuNR passivated with polyelectrolyte (PE) ligand shell (AuNR-PE) has hitherto left a vital knowledge gap between the mechanical stability of the ligand shell and the cytotoxicity of AuNR-PEs. Here, the agreement between unbiased coarse-grained molecular dynamics (CGMD) simulation and empirical outcomes on hemolysis of red blood cells by AuNR-PEs demonstrates for the first time, a direct impact of the mechanical stability of the PE shell passivating the AuNRs on the lipid membrane rupture. Such mechanical stability is ultimately modulated by the rigidity of the PE components. The CGMD simulation results also reveal the mechanism where the PE chain adsorbs near the surface of the lipid bilayer without penetrating the hydrophobic core of the bilayer, which allows the hydrophobic AuNR core to be in direct contact with the hydrophobic interior of the lipid bilayer, thereby perforating the lipid membrane to induce membrane damage.

Targeting Tumorigenicity of Breast Cancer Stem Cells Using SAHA/Wnt-b Catenin Antagonist Loaded Onto Protein Corona of Gold Nanoparticles

BACKGROUND

Among various theories for the origin of cancer, the "stemness phenotype model" suggests a dynamic feature for tumor cells in which non-cancer stem cells (non-CSCs) can inter-convert to CSCs. Differentiation with histone-deacetylase inhibitor, vorinostat (SAHA), can induce stem cells to differentiate as well as enforces non-CSCs to reprogram to CSCs. To avoid this undesirable effect, one can block the Wnt-βcatenin pathway. Thus, a dual delivery system of SAHA and a Wnt-βcatenin blocker will be beneficial in the induction of differentiation of CSCs. Protein corona (PC) formation in nanoparticle has a biologic milieu, and despite all problematic properties, it can be employed as a medium for dual loading of the drugs.

MATERIALS AND METHODS

We prepared sphere gold nanoparticles (GNPs) with human plasma protein corona loaded with SAHA as differentiating agent and PKF118-310 (PKF) as a Wnt-βcatenin antagonist. The MCF7 breast cancer stem cells were treated with NPs and the viability and differentiation were evaluated by Western blotting and sphere formation assay.

RESULTS

We found that both drugs loaded onto corona-capped GNPs had significant cytotoxicity in comparison to bare GNP-corona. Data demonstrated an increase in stem cell population and upregulation of mesenchymal marker, Snail by SAHA-loaded GNPs treatment; however, the combination of PKF loaded GNPs along with SAHA-loaded GNPs resulted in a reduction of stem cell populations and Snail marker. We have shown that in MCF7 and its CSCs simultaneous treatment with SAHA and PKF118-310 induced differentiation and inhibition of Snail induction.

CONCLUSION

Our study reveals the PC-coated GNPs as a biocompatible career for both hydrophilic (PKF) and hydrophobic (SAHA) agents which can decrease breast cancer stem cell populations along with reduced stemness state regression.

Innate immune activation by conditioned medium of cancer cells following combined phototherapy with photosensitizer-loaded gold nanorods

Nanoparticle-based phototherapy has evolved to include immunotherapy as an effective treatment combination for cancers through inducing anti-cancer immune activation leading to downstream adaptive responses and immune protection.

Understanding the relevance of protein corona in nanoparticle-based therapeutics and diagnostics

Over the past few decades, nanoparticle-based therapeutic and diagnostic systems have gained immense recognition. A relative improvement in the status of the global cancer burden has been successful due to the advent of nanoparticle-based formulations. However, exposure of nanoparticles (NPs) to a real-time biological media alters its native identity due to the formation of the biomolecular corona. Such biological interactions hinder the efficiency of the NPs system. The parameters that govern such intricate interaction are generally overlooked while designing nano drugs and delivery systems (nano-DDS). Fabricating nano-DDS with prolonged circulation time, enhanced drug-loading, and release capacity along with efficient clearance, remain the primary concerns associated with cancer therapeutics. This present review firstly aims to summarize the critical aspects that influence protein coronation on therapeutic nanoparticles designed for anti-cancer therapy. The role of protein corona in modifying the overall pharmacodynamics of the nanoparticle-based DDS has been discussed. Further, the studies and patents that extend the concept of protein corona into diagnostics have been elaborated. An understanding of the pros and cons associated with protein coronation would not only help us gain better insights into the fabrication of effective anti-cancer drug-delivery systems but also improve the shortcomings related to the clinical translation of these nanotherapeutics.

Protein corona and its applications.

Gold nanoparticles: New routes across old boundaries

In recent years, gold nanoparticles have emerged as unique non-invasive drug carriers for targeting drugs to their site of action. Their site specificity has helped in increasing drugs' efficacy at lower dose as well as reduction in their side effects. Moreover, their excellent optical properties and small size offer their utilization as diagnostic tools to diagnose tumors as well as other diseases. This review focuses on various approaches that have been used in last several years for preparation of gold nanoparticles, their characterization techniques and theranostic applications. Their toxicity related aspects are also highlighted. Gold nanoparticles are useful as theranostic agents, owing to their small size, biocompatible nature, size dependent physical, chemical and optical properties etc. However, the challenges associated with these nanoparticles such as scale up, cost, low drug payload, toxicity and stability have been the major impediments in their commercialization. The review looks into all these critical issues and identifies the possibilities to overcome these challenges for successful positioning of metallic nanoparticles in market.

In vivo comparison of the biodistribution and long-term fate of colloids – gold nanoprisms and nanorods – with minimum surface modification

Aim: To study the difference in biodistribution of gold nanoprisms (NPr) and nanorods (NR), PEGylated to ensure colloidal stability. Materials & methods: Surface changes were studied for nanoparticles in different media, while the biodistribution was quantified and imaged in vivo. Results: Upon interaction with the mouse serum, NR showed more abrupt changes in surface properties than NPr. In the in vivo tests, while NPr accumulated similarly in the spleen and liver, NR showed much higher gold presence in the spleen than in liver; together with some accumulation in kidneys, which was nonexistent in NPr. NPr were cleared from the tissues 2 months after administration, while NR were more persistent. Conclusion: The results suggest that the differential biodistribution is caused by size-/shape-dependent interactions with the serum.

Nanobiomaterials: from 0D to 3D for tumor therapy and tissue regeneration

Nanobiomaterials have attracted tremendous attention in the biomedical field. Especially in the past few years, a large number of low dimensional nanobiomaterials, including 0D nanostructures, 1D nanotubes and 2D nanosheets, were employed for tumor therapy due to their optically triggered tumor therapy effects and drug loading capacities. However, these low dimensional nanobiomaterials cannot support cell adhesion and possess poor tissue regeneration ability, thus they are not suitable for application in regenerative medicine. Three dimensional (3D) nanofiber scaffolds have attracted extensive attention in tissue regeneration, including bone, skin, nerve and cardiac tissues, due to their similar extracellular matrix structures. Additionally, many 3D scaffolds displayed bone and cartilage regeneration abilities. Therefore, to obtain materials with both tumor therapy and tissue regeneration abilities, it is meaningful and necessary to develop 3D nanobiomaterials with multifunctions. In this review, we systematically review the research progress of nanobiomaterials with varied dimensional structures including 0D, 1D, 2D and 3D, as well as evolutional functions from single tumor therapy to simultaneous tumor therapy and tissue regeneration. This review may pave the way for developing an interdisciplinary research of nanobiomaterials in combination of tumor therapy and regenerative medicine.

A health concern regarding the protein corona, aggregation and disaggregation

Nanoparticle (NP)-protein complexes exhibit the "correct identity" of NP in biological media. Therefore, protein-NP interactions should be closely explored to understand and modulate the nature of NPs in medical implementations. This review focuses mainly on the physicochemical parameters such as dimension, surface chemistry, morphology of NPs, and influence of pH on the formation of protein corona and conformational changes of adsorbed proteins by different kinds of techniques. Also, the impact of protein corona on the colloidal stability of NPs is discussed. Uncontrolled protein attachment on NPs may bring unwanted impacts such as protein denaturation and aggregation. In contrast, controlled protein adsorption by optimal concentration, size, pH, and surface modification of NPs may result in potential implementation of NPs as therapeutic agents especially for disaggregation of amyloid fibrils. Also, the effect of NPs-protein corona on reducing the cytotoxicity and clinical implications such as drug delivery, cancer therapy, imaging and diagnosis will be discussed. Validated correlative physicochemical parameters for NP-protein corona formation frequently derived from protein corona fingerprints of NPs which are more valid than the parameters obtained only on the base of NP features. This review may provide useful information regarding the potency as well as the adverse effects of NPs to predict their behavior in vivo.

Protease Degradation of Protein Coronas and Its Impact on Cancer Cells and Drug Payload Release

The effect of matrix metalloproteinases (MMPs) on preformed protein coronas around spherical gold nanoparticles (AuNPs) was studied. Protein coronas of different compositions (human serum, human serum albumin, and collagen IV) were formed around AuNPs and characterized. The protease MMP-9 had different effects on the corona depending on the corona composition, resulting in different changes to the corona hydrodynamic diameter ( D_H). When incubated with PANC-1 cells, the corona showed evidence of both increases as well as decreases in D_H. Varying the composition of the corona influenced the MMP-9 activity. Furthermore, the corona was influenced not only by the protease activity of the MMP-9 but also by its ability to exchange with proteins in the preformed corona. This exchange could also occur with proteins in the media. Thus, the net effect of the MMP-9 was a combination of the MMP-9 protease activity and also exchange. Time scales for the exchange varied depending on the nature that make up the protein corona (weakly vs strongly bound corona proteins). Mass spectrometry was used to probe the protein corona composition and supported the exchange and degradation model. Together, these results indicate that the mechanism of protease activity on AuNP coronas involves both rearrangement and exchange, followed by degradation.

Quantifying Vascular Distribution and Adhesion of Nanoparticles with Protein Corona in Microflow

The protein corona has emerged as an important determinant of biological response in nanoparticle (NP) drug delivery. However, there is presently no reported study on how the protein corona affects the behavior of NPs in microflow and its subsequent interactions with the vascular endothelium, which could affect their delivery to the target tumor site regardless of its targeting mechanism. Furthermore, a consensus on the role of physical and surface characteristics of NPs in affecting the margination of NPs is lacking due to different methods of quantifying margination. In this study, we examine how the particle adhesion (PA) method and particle distribution (PD) method quantify the margination of 20, 40, 100, and 200 nm polystyrene NPs (pNPs) differently in fibronectin or pluronic F-127-coated microfluidic straight channels. We found that PA reduced with increasing pNP size, whereas the PD was similar across all pNP sizes regardless of channel coating. We then formed a protein corona on all pNPs (pNPs-PC) and found that the protein corona increased the adhesion of 40-200 nm pNPs in fibronectin-coated channels, with no size dependence between them except for 40 nm, which had significantly higher particle adhesion. The PA method was also dependent on channel coating, whereas the PD method was independent of channel coating. These results suggested that the PA method was more amenable to surface interactions between the pNPs and the channel wall while providing a measure of the amount of NPs that interacted with the channel walls, whereas the PD method provided a representation of their distribution across the channel due to margination. The two methods complement each other to elucidate a more holistic understanding of how different factors might affect a NP's margination in future studies.

Recent biomedical applications of gold nanoparticles: A review

Recent advances in nanotechnology are as a result of the development of engineered nanoparticles. Efficiently, metallic nanoparticles have been widely exploited for biomedical application and among them, gold nanoparticles (AuNPs) are highly remarkable. Consequent upon their significant nature, spherical and gold nanorods (Au NRs) nanoparticles attract extreme attention. Their intrinsic features such as optical, electronic, physicochemical and, surface plasmon resonance (SPR); which can be altered by changing the characterizations of particles such as shape, size, aspect ratio, or environment; ease of synthesis and functionalization properties have resulted to various applications in different fields of biomedicine such as sensing, targeted drug delivery, imaging, photothermal and photodynamic therapy as well as the modulation of two or three applications. This article reviewed the popular AuNPs synthesis methods and mentioned their established applications in various demands, especially in biological sensing.

Protein corona in drug delivery for multimodal cancer therapy in vivo

The protein corona is inevitably formed on nanoparticles (NPs) when they are introduced in vivo and has been associated with a reduction in targeting yield, immune recognition and rapid blood clearance, leading to poor tumor accumulation. We have recently shown that it is possible to exploit the protein corona for drug delivery by exploiting it for loading and triggering the release of a photosensitizer Chlorin e6 (Ce6) for simultaneous photodynamic (PDT) and photothermal therapy (PTT) in vitro. Here, we extended our previous in vitro studies to evaluate its effectiveness in vivo. Specifically, we pre-formed the protein corona from mouse serum (MS) around gold nanorods (NRs) and loaded it with Ce6 to form NR-MS-Ce6. The intravenous delivery of NR-MS-Ce6 at a dose of 10 mg kg^-1 Au loaded with 9.63 μg kg^-1 Ce6 into tumor-bearing NCr nude mice resulted in their tumor accumulation reaching a peak concentration of 560.3 μg Au per kg tissue (0.0752% dose) within 6 h post-injection. Subsequent localized laser irradiation of the xenograft tumor resulted in a significant tumor temperature increase of 16.85 °C within 20 min. Combined with the simultaneous reactive oxygen species (ROS) production by Ce6 for PDT, complete tumor regression was achieved within 19 days with no tumor regrowth up to 31 days. Similar to other NPs, significant gold accumulation was observed in the major reticuloendothelial system (RES) organs, particularly the liver and spleen, although no acute toxicity was observed histologically 31 days post-treatment. Our results demonstrated for the first time an in vivo application of the protein corona around NPs in the loading and delivery of drugs in small animals. The ease of drug loading and the biocompatibility of the endogenous serum-based protein corona could make it useful for drug delivery and therapeutic applications instead of merely being considered as a biological artefact to be eliminated.

Nanoparticles based on glycyrrhetinic acid modified porphyrin for photodynamic therapy of cancer

Nanoparticles were prepared from amphiphilic glycyrrhetinic acid–porphyrin conjugates (TPP–GA) and applied for the photodynamic therapy of cancer.

Human serum albumin corona on functionalized gold nanorods modulates doxorubicin loading and release

Human serum albumin corona around functionalized gold nanorods can modulate doxorubicin loading and release.

Protein Corona around Gold Nanorods as a Drug Carrier for Multimodal Cancer Therapy

A single nanodevice based on gold nanorods (NRs) coloaded with a photosensitizer, Chlorin e6 (Ce6), and a chemotherapeutic, Doxorubicin (Dox), on its endogenously formed human serum (HS) protein corona, i.e., NR-HS-Ce6-Dox was developed with the aim of performing multimodal cancer therapy: photodynamic (PDT), photothermal (PTT) and chemotherapy (CTX) simultaneously upon irradiation with a single 665 nm laser. Here, the excitation of NRs and Ce6 resulted in photothermal ablation (PTT), and production of reactive oxygen species (ROS) to kill Cal 27 oral squamous cell carcinoma (OSCC) cells by oxidative stress (PDT) respectively, while the laser-triggered release of Dox intercalated into the DNA of cancer cells to result in DNA damage and cell death (CTX). High laser-triggered Dox release efficiency of 71.5% and strong plasmonic enhancement of ROS production by Ce6 (4.8-fold increase compared to free Ce6) was observed. Uptake of both Ce6 and Dox by Cal 27 cells was greatly enhanced, with 3.3 and 52 times higher intracellular Dox and Ce6 fluorescence observed, respectively, 6 h after dosing with NR-HS-Ce6-Dox compared to free drugs. The simultaneous trimodal therapy achieved a near complete eradication of cancer cells (98.7% cell death) with an extremely low dose of 15 pM NR-HS-Ce6-Dox loaded with just 1.26 nM Ce6 and 12.5 nM Dox due to strong synergistic enhancement in cancer cell kill compared to individual therapies performed separately. No dark toxicities were observed. These drug concentrations were far lower than any previously reported in vitro, thus eliminating any potential systemic toxicity of these agents.

Exploiting the Protein Corona from Cell Lysate on DNA Functionalized Gold Nanoparticles for Enhanced mRNA Translation

This study describes the use of DNA functionalized gold nanoparticles (AuNPs) to enhance the synthesis of proteins in cell lysate and examines the mechanisms behind the enhanced mRNA translation. With an appropriate DNA oligomer sequence that hybridizes to the 3'-untranslated region of two mRNA of interest, insulin and green fluorescent protein (GFP), we found that these DNA conjugated AuNPs (AuNP-DNA) introduced into HeLa cell lysate enhanced the synthesis of insulin and GFP by up to 2.18 and 1.80-fold, respectively, over baseline production with just the mRNA present. The insulin synthesis was markedly reduced with non-DNA citrate-capped AuNP (1.25-fold) and AuNP-DNA with a nonspecific poly(T) sequence (1.25-fold). We showed that both nonspecific adsorption of ribosomes and translation factors to form a lysate protein corona on AuNP-DNA and weak hybridization between DNA oligomers and mRNA of interest were important factors that brought translation factors, ribosomes, and mRNA into close proximity of each other. This could reduce the recycling time of ribosomes during mRNA translation, thereby increasing the efficiency of protein synthesis. The outcome of this work shows that with rational DNA design, it could be possible to modulate intracellular biological processes with AuNP-DNA and increase their production of proteins for various biomedical applications.