DNA-Nanostructure-Gold-Nanorod Hybrids for Enhanced In Vivo Optoacoustic Imaging and Photothermal Therapy

Thermal analysis of laser irradiation-gold nanorod combinations at 808 nm, 940 nm, 975 nm and 1064 nm wavelengths in breast cancer model

Background

Photothermal therapy is currently under the spotlight to improve the efficacy of minimally invasive thermal treatment of solid tumors. The interplay of several factors including the radiation wavelengths and the nanoparticle characteristics underlie the thermal outcome. However, a quantitative thermal analysis in in vivo models embedding nanoparticles and under different near-infrared (NIR) wavelengths is missing.

Purpose

We evaluate the thermal effects induced by different combinations of NIR laser wavelengths and gold nanorods (GNRs) in breast cancer tumor models in mice.

Materials and methods

Four laser wavelengths within the therapeutic window, i.e., 808, 940, 975, and 1064 nm were employed, and corresponding GNRs were intratumorally injected. The tissue thermal response was evaluated in terms of temperature profile and time constants, considering the step response of a first-order system as a model.

Results

The 808 nm and 1064 nm lasers experienced the highest temperature enhancements (>24%) in presence of GNRs compared to controls; conversely, 975 nm and 940 nm lasers showed high temperatures in controls due to significant tissue absorption and the lowest temperature difference with and without GNRs (temperature enhancement <10%). The presence of GNRs resulted in small time constants, thus quicker laser-induced thermal response (from 67 s to 33 s at 808 nm).

Conclusions

The thermal responses of different GNR-laser wavelength combinations quantitatively validate the widespread usage of 808 nm laser for nanoparticle-assisted photothermal procedures. Moreover, our results provide insights on other usable wavelengths, toward the identification of an effective photothermal treatment strategy for the removal of focal malignancies.

DNA Nanotechnology-Based Biosensors and Therapeutics

Over the past few decades, DNA nanotechnology engenders a vast variety of programmable nanostructures utilizing Watson-Crick base pairing. Due to their precise engineering, unprecedented programmability, and intrinsic biocompatibility, DNA nanostructures cannot only interact with small molecules, nucleic acids, proteins, viruses, and cancer cells, but also can serve as nanocarriers to deliver different therapeutic agents. Such addressability innate to DNA nanostructures enables their use in various fields of biomedical applications such as biosensors and cancer therapy. This review is begun with a brief introduction of the development of DNA nanotechnology, followed by a summary of recent applications of DNA nanostructures in biosensors and therapeutics. Finally, challenges and opportunities for practical applications of DNA nanotechnology are discussed.

131I-Labeled Multifunctional Polyethylenimine/Doxorubicin Complexes with pH-Controlled Cellular Uptake Property for Enhanced SPECT Imaging and Chemo/Radiotherapy of Tumors

Introduction

Smart theranostic nanosystems own a favorable potential to improve internalization within tumor while avoiding nonspecific interaction with normal tissues. However, development of this type of theranostic nanosystems is still a challenge.

Methods

In this study, we developed the iodine-131 (¹³¹I)-labeled multifunctional polyethylenimine (PEI)/doxorubicin (DOX) complexes with pH-controlled cellular uptake property for enhanced single-photon emission computed tomography (SPECT) imaging and chemo/radiotherapy of tumors. Alkoxyphenyl acylsulfonamide (APAS), a typical functional group that could achieve improved cellular uptake of its modified nanoparticles, was utilized to conjugate onto the functional PEI pre-modified with polyethylene glycol (PEG) with terminal groups of monomethyl ether and N-hydroxysuccinimide (mPEG-NHS), PEG with terminal groups of maleimide and succinimidyl valerate (MAL-PEG-SVA) through sulfydryl of APAS and MAL moiety of MAL-PEG-SVA. This was followed by conjugation with 3-(4’-hydroxyphenyl)propionic acid-OSu (HPAO), acetylating leftover amines of PEI, complexing DOX and labeling ¹³¹I to generate the theranostic nanosystems.

Results

The synthesized theranostic nanosystems exhibit favorable water solubility and stability. Every functional PEI can complex approximately 12.4 DOX, which could sustainably release of DOX following a pH-dependent manner. Remarkably, due to the surface modification of APAS, the constructed theranostic nanosystems own the capacity to achieve pH-responsive charge conversion and further lead to improved cellular uptake in cancer cells under slightly acidic condition. Above all, based on the coexistence of DOX and radioactive ¹³¹I in the single nanosystem, the synthesized nanohybrid system could afford enhanced SPECT imaging and chemo/radioactive combination therapy of cancer cells in vitro and xenografted tumor model in vivo.

Discussion

The developed smart nanohybrid system provides a novel strategy to improve the tumor theranostic efficiency and may be applied for different types of cancer.

Ferrous ions doped layered double hydroxide: smart 2D nanotheranostic platform with imaging-guided synergistic chemo/photothermal therapy for breast cancer

Developing simple and efficient nanotheranostic platforms with behavior responsive to the acid microenvironment of a tumor is of great significance for accurate tumor diagnosis and therapy. In this study, a smart 2D nanotheranostic platform has been successfully fabricated by doping functional ferrous ions into as-synthesized MgAl-layered double hydroxide (LDH) with doxurubicin (DOX) loading to form Fe-LDH/DOX NPs, which achieved magnetic resonance imaging (MRI)-guided synergistic chemo/photothermal therapy for breast cancer. The doping of ferrous ions into Fe-LDH/DOX enabled a strong photo-induced heating ability with a high photothermal conversion efficiency of 45.67%, which could be combined with the antitumor drug DOX to achieve the synergistic effect of photothermal therapy (PTT) and chemotherapy for killing tumor cells. Additionally, its in vitro pH-dependent degradation behavior and T₂-weighted MRI effect revealed that the as-prepared Fe-LDH/DOX is sensitive to the tumor acid microenvironment. Most importantly, the growth rate of tumors in 4T1 bearing mice could be effectively inhibited after the synergistic treatment of PTT and chemotherapy by Fe-LDH/DOX. These results show that doping functional metal ions into LDH NPs may open a novel approach to fabricating an LDH NP-based nanotheranostics platform with advanced diagnostic and therapeutic performances.

DNA Based and Stimuli-Responsive Smart Nanocarrier for Diagnosis and Treatment of Cancer: Applications and Challenges

The rapid development of multidrug co-delivery and nano-medicines has made spontaneous progress in tumor treatment and diagnosis. DNA is a unique biological molecule that can be tailored and molded into various nanostructures. The addition of ligands or stimuli-responsive elements enables DNA nanostructures to mediate highly targeted drug delivery to the cancer cells. Smart DNA nanostructures, owing to their various shapes, sizes, geometry, sequences, and characteristics, have various modes of cellular internalization and final disposition. On the other hand, functionalized DNA nanocarriers have specific receptor-mediated uptake, and most of these ligand anchored nanostructures able to escape lysosomal degradation. DNA-based and stimuli responsive nano-carrier systems are the latest advancement in cancer targeting. The data exploration from various studies demonstrated that the DNA nanostructure and stimuli responsive drug delivery systems are perfect tools to overcome the problems existing in the cancer treatment including toxicity and compromised drug efficacy. In this light, the review summarized the insights about various types of DNA nanostructures and stimuli responsive nanocarrier systems applications for diagnosis and treatment of cancer.

Biomacromolecule-based photo-thermal agents for tumor treatment

Cancer treatment has become one of the biggest challenges in modern medicine. Recently, many efforts have been devoted to treat tumors by surgical resection, radiotherapy, or chemotherapy. In comparison to these methods, photo-thermal therapy (PTT) with noninvasive, controllable, direct, and precise characteristics has received tremendous attention in eliminating tumor cells over the past decades. In particular, PTT based on biomacromolecule-based photo-thermal agents (PTAs) outperforms other systems with high photo-thermal efficiency, simple coating, and low immunogenicity. Considering the unique advantages of biomacromolecule-based PTAs in tumor treatment, it is necessary to summarize the recent progress in the field of biomacromolecule-based PTAs for tumor treatment. Herein, this minireview outlines recent progress in the fabrication and applications of biomacromolecule-based PTAs. Within this framework, various types of biomacromolecule-based PTAs are highlighted, including cell-based agents, protein-based agents, nucleotide-based agents, and polysaccharide-based PTAs. In each section, the functional design, photo-thermal effects, and potential clinical applications of each type of PTA are discussed. Finally, a brief perspective for the development of biomacromolecule-based PTAs is presented.

Improvement of Gold Nanorods in Photothermal Therapy: Recent Progress and Perspective

Cancer is a life-threatening disease, and there is a significant need for novel technologies to treat cancer with an effective outcome and low toxicity. Photothermal therapy (PTT) is a noninvasive therapeutic tool that transports nanomaterials into tumors, absorbing light energy and converting it into heat, thus killing tumor cells. Gold nanorods (GNRs) have attracted widespread attention in recent years due to their unique optical and electronic properties and potential applications in biological imaging, molecular detection, and drug delivery, especially in the PTT of cancer and other diseases. This review summarizes the recent progress in the synthesis methods and surface functionalization of GNRs for PTT. The current major synthetic methods of GNRs and recently improved measures to reduce toxicity, increase yield, and control particle size and shape are first introduced, followed by various surface functionalization approaches to construct a controlled drug release system, increase cell uptake, and improve pharmacokinetics and tumor-targeting effect, thus enhancing the photothermal effect of killing the tumor. Finally, a brief outlook for the future development of GNRs modification and functionalization in PTT is proposed.

Hyaluronic acid functionalized gold nanorods combined with copper-based therapeutic agents for chemo-photothermal cancer therapy

We herein report a hybrid nanocomposite (AuNRs-CTN@THA) which is based on hyaluronic acid-coated gold nanorods with loading of a copper complex through strong bonds. AuNRs-CTN@THA exhibits durable photothermal conversion capacity for pH-dominant and pH/temperature dual sensitive drug release, accomplishing synergetic antitumor efficacy and deep tumor penetration.

Rationally Programming Nanomaterials with DNA for Biomedical Applications

DNA is not only a carrier of genetic information, but also a versatile structural tool for the engineering and self-assembling of nanostructures. In this regard, the DNA template has dramatically enhanced the scalability, programmability, and functionality of the self-assembled DNA nanostructures. These capabilities provide opportunities for a wide range of biomedical applications in biosensing, bioimaging, drug delivery, and disease therapy. In this review, the importance and advantages of DNA for programming and fabricating of DNA nanostructures are first highlighted. The recent progress in design and construction of DNA nanostructures are then summarized, including DNA conjugated nanoparticle systems, DNA-based clusters and extended organizations, and DNA origami-templated assemblies. An overview on biomedical applications of the self-assembled DNA nanostructures is provided. Finally, the conclusion and perspectives on the self-assembled DNA nanostructures are presented.

DNA origami: an outstanding platform for functions in nanophotonics and cancer therapy

Due to the proposal and evolution of the DNA origami technique over the past decade, DNA molecules have been utilized as building blocks for the precise construction of nanoscale architectures. Benefiting from the superior programmability of DNA molecules, the sequence-dependent recognition mechanism and robust complementation among DNA strands make it possible to customize almost arbitrary structures. Such an assembly strategy bypasses some of the limits of conventional fabrication methods; the fabrication accuracy and complexity of the target product are unprecedentedly promoted as well. Furthermore, due to the spatial addressability of the final products, nanostructures assembled through the DNA origami technique can also serve as a versatile platform for the spatial positioning of functional elements, represented by colloidal nanoparticles (NPs). The subsequent fabrication of heterogeneous functional nanoarchitectures is realized via modifying colloidal NPs with DNA strands and manipulating them to anchor into DNA origami templates. This has given rise to investigations of their novel properties in nanophotonics and therapeutic effects towards some diseases. In this review, we survey the crucial progress in the development of DNA origami design, assembly and structural analysis and summarize available applications in nanophotonics and cancer therapy based on the object-dressed DNA origami complex. Moreover, we elucidate the development of this field and discuss the potential directions of this kind of application-oriented nanomanufacturing.

DNA Nanostructures in the Fight Against Infectious Diseases

Throughout history, humanity has been threatened by countless epidemic and pandemic outbreaks of infectious diseases, from the Justinianic Plague to the Spanish flu to COVID-19. While numerous antimicrobial and antiviral drugs have been developed over the last 200 years to face these threats, the globalized and highly connected world of the 21st century demands for an ever-increasing efficiency in the detection and treatment of infectious diseases. Consequently, the rapidly evolving field of nanomedicine has taken up the challenge and developed a plethora of strategies to fight infectious diseases with the help of various nanomaterials such as noble metal nanoparticles, liposomes, nanogels, and virus capsids. DNA nanotechnology represents a comparatively recent addition to the nanomedicine arsenal, which, over the past decade, has made great progress in the area of cancer diagnostics and therapy. However, the past few years have seen also an increasing number of DNA nanotechnology-related studies that particularly focus on the detection and inhibition of microbial and viral pathogens. Herein, a brief overview of this rather young research field is provided, successful concepts as well as potential challenges are identified, and promising directions for future research are highlighted.

Genetically Encoded and Biologically Produced All-DNA Nanomedicine Based on One-Pot Assembly of DNA Dendrimers for Targeted Gene Regulation

All-DNA nanomedicines have emerged as potential anti-tumor drugs. DNA nanotechnology provides all-DNA nanomedicines with unlimited possibilities in controlling the diversification of size, shape, and loads of the therapeutic motifs. As DNA is a biological polymer, it is possible to genetically encode and produce the all-DNA nanomedicines in living bacteria. Herein, DNA-dendrimer-based nanomedicines are designed to adapt to the biological production, which is constructed by the flexible 3-arm building blocks to enable a highly efficient one-pot DNA assembly. For the first time, a DNA nanomedicine, D4-3-As-DzSur, is successfully genetically encoded, biotechnologically produced, and directly self-assembled. The performance of the biologically produced D4-3-As-DzSur in targeted gene regulation has been confirmed by in vitro and in vivo studies. The biological production capability will fulfill the low-cost and large-scale production of all-DNA nanomedicines and promote clinical applications.

Smart Nanocarriers for Targeted Cancer Therapy

Cancer is considered one of the most threatening diseases worldwide. Although many therapeutic approaches have been developed and optimized for ameliorating patient's conditions and life expectancy, however, it frequently remains an incurable pathology. Notably, conventional treatments may reveal inefficient in the presence of metastasis development, multidrug resistance and inability to achieve targeted drug delivery. In the last decades, nanomedicine has gained a prominent role, due to many properties ascribable to nanomaterials. It is worth mentioning their small size, their ability to be loaded with small drugs and bioactive molecules and the possibility to be functionalized for tumor targeting. Natural vehicles have been exploited, such as exosomes, and designed, such as liposomes. Biomimetic nanomaterials have been engineered, by modification with biological membrane coating. Several nanoparticles have already entered clinical trials and some liposomal formulations have been approved for therapeutic applications. In this review, natural and synthetic nanocarriers functionalized for actively targeting cancer cells will be described, focusing on their advantages with respect to conventional treatments. Recent innovations related to biomimetic nanoparticles camouflaged with membranes isolated from different types of cells will be reported, together with their promising applications. Finally, a short overview on the latest advances in carrier-free nanomaterials will be provided.

Hybrid Nanosystems for Biomedical Applications

Inorganic/organic hybrid nanosystems have been increasingly developed for their versatility and efficacy at overcoming obstacles not readily surmounted by nonhybridized counterparts. Currently, hybrid nanosystems are implemented for gene therapy, drug delivery, and phototherapy in addition to tissue regeneration, vaccines, antibacterials, biomolecule detection, imaging probes, and theranostics. Though diverse, these nanosystems can be classified according to foundational inorganic/organic components, accessory moieties, and architecture of hybridization. Within this Review, we begin by providing a historical context for the development of biomedical hybrid nanosystems before describing the properties, synthesis, and characterization of their component building blocks. Afterward, we introduce the architectures of hybridization and highlight recent biomedical nanosystem developments by area of application, emphasizing hybrids of distinctive utility and innovation. Finally, we draw attention to ongoing clinical trials before recapping our discussion of hybrid nanosystems and providing a perspective on the future of the field.

Induction of Cytokines by Nucleic Acid Nanoparticles (NANPs) Depends on the Type of Delivery Carrier

Recent insights into the immunostimulatory properties of nucleic acid nanoparticles (NANPs) have demonstrated that variations in the shape, size, and composition lead to distinct patterns in their immunostimulatory properties. While most of these studies have used a single lipid-based carrier to allow for NANPs' intracellular delivery, it is now apparent that the platform for delivery, which has historically been a hurdle for therapeutic nucleic acids, is an additional means to tailoring NANP immunorecognition. Here, the use of dendrimers for the delivery of NANPs is compared to the lipid-based platform and the differences in resulting cytokine induction are presented.

Hyaluronic acid modified covalent organic polymers for efficient targeted and oxygen-evolved phototherapy

The integration of multiple functions with organic polymers-based nanoagent holds great potential to potentiate its therapeutic efficacy, but still remains challenges. In the present study, we design and prepare an organic nanoagent with oxygen-evolved and targeted ability for improved phototherapeutic efficacy. The iron ions doped poly diaminopyridine (FeD) is prepared by oxidize polymerization and modified with hyaluronic acid (HA). The obtained FeDH appears uniform morphology and size. Its excellent colloidal stability and biocompatibility are demonstrated. Specifically, the FeDH exhibits catalase-like activity in the presence of hydrogen peroxide. After loading of photosensitizer indocyanine green (ICG), the ICG@FeDH not only demonstrates favorable photothermal effect, but also shows improved generation ability of reactive oxygen species (ROS) under near-infrared laser irradiation. Moreover, the targeted uptake of ICG@FeDH in tumor cells is directly observed. As consequence, the superior phototherapeutic efficacy of the targeted ICG@FeDH over non-targeted counterparts is also confirmed in vitro and in vivo. Hence, the results demonstrate that the developed nanoagent rationally integrates the targeted ability, oxygen-evolved capacity and combined therapy in one system, offering a new paradigm of polymer-based nanomedicine for tumor therapy.

Activatable NIR-II Plasmonic Nanotheranostics for Efficient Photoacoustic Imaging and Photothermal Cancer Therapy

Precise manipulation of optical properties through the structure-evolution of plasmonic nanoparticles is of great interest in biomedical fields including bioimaging and phototherapy. However, previous success has been limited to fixed assembled structures or visible-NIR-I absorption. Here, an activatable NIR-II plasmonic theranostics system based on silica-encapsulated self-assembled gold nanochains (AuNCs@SiO2 ) for accurate tumor diagnosis and effective treatment is reported. This transformable chain structure breaks through the traditional molecular imaging window, whose absorption can be redshifted from the visible to the NIR-II region owing to the fusion between adjacent gold nanoparticles in the restricted local space of AuNCs@SiO2 triggered by the high H2 O2 level in the tumor microenvironment (TME), leading to the generation of a new string-like structure with strong NIR-II absorption, which is further confirmed by finite-difference-time-domain (FDTD) simulation. With the TME-activated characteristics, AuNCs@SiO2 exhibits excellent properties for photoacoustic imaging and a high photothermal conversion efficiency of 82.2% at 1064 nm leading to severe cell death and remarkable tumor growth inhibition in vivo. These prominent intelligent TME-responsive features of AuNCs@SiO2 may open up a new avenue to explore optical regulated nano-platform for intelligent, accurate, and noninvasive theranostics in NIR-II window.

Plasmonic gold nanostructures for biosensing and bioimaging

As one kind of noble metal nanostructures, the plasmonic gold nanostructures possess unique optical properties as well as good biocompatibility, satisfactory stability, and multiplex functionality. These distinctive advantages make the plasmonic gold nanostructures an ideal medium in developing methods for biosensing and bioimaging. In this review, the optical properties of the plasmonic gold nanostructures were firstly introduced, and then biosensing in vitro based on localized surface plasmon resonance, Rayleigh scattering, surface-enhanced fluorescence, and Raman scattering were summarized. Subsequently, application of the plasmonic gold nanostructures for in vivo bioimaging based on scattering, photothermal, and photoacoustic techniques  has been also briefly covered. At last, conclusions of the selected examples are presented and an outlook of this research topic is given.

DNA-Based Nanocarriers to Enhance the Optoacoustic Contrast of Tumors In Vivo

Optoacoustic tomography (OT) enables non-invasive deep tissue imaging of optical contrast at high spatio-temporal resolution. The applications of OT in cancer imaging often rely on the use of molecular imaging contrast agents based on near-infrared (NIR) dyes to enhance contrast at the tumor site. While these agents afford excellent biocompatibility and minimal toxicity, they present limited optoacoustic signal generation capability and rapid renal clearance, which can impede their tumor imaging efficacy. In this work, a synthetic strategy to overcome these limitations utilizing biodegradable DNA-based nanocarrier (DNA-NC) platforms is introduced. DNA-NCs enable the incorporation of NIR dyes (in this case, IRDye 800CW) at precise positions to enable fluorescence quenching and maximize optoacoustic signal generation. Furthermore, these DNA-NCs show a prolonged blood circulation compared to the native fluorophores, facilitating tumor accumulation by the enhanced permeability and retention (EPR) effect. In vivo imaging of tumor xenografts in mice following intravenous administration of DNA-NCs reveals enhanced OT signals at 24 h when compared to free fluorophores, indicating promise for this method to enhance the optoacoustic signal generation capability and tumor uptake of clinically relevant NIR dyes.

CRISPR-cas9 genome editing delivery systems for targeted cancer therapy

The prokaryotic CRISPR-Cas systems could be applied as revolutionized genome editing tool in live cells of various species to modify, visualize and identify definite sequences of DNA and RNA. CRISPR-Cas could edit the genome by homology-directed repair and non-homologous end joining mechanisms. Furthermore, DNA-targeting modification by CRISPR-Cas methodology provides opportunity for diagnosis, therapy and the genetic disorders investigation. Here, we summarized delivery systems employed for CRISPR-Cas9 for genome editing. Then preclinical studies of the CRISPR-Cas9-based therapeutics will be discussed considering the associated challenges and developments in its translation to clinic for cancer therapy.

DNA Nanostructures and DNA-Functionalized Nanoparticles for Cancer Theranostics

In the last two decades, DNA has attracted significant attention toward the development of materials at the nanoscale for emerging applications due to the unparalleled versatility and programmability of DNA building blocks. DNA-based artificial nanomaterials can be broadly classified into two categories: DNA nanostructures (DNA-NSs) and DNA-functionalized nanoparticles (DNA-NPs). More importantly, their use in nanotheranostics, a field that combines diagnostics with therapy via drug or gene delivery in an all-in-one platform, has been applied extensively in recent years to provide personalized cancer treatments. Conveniently, the ease of attachment of both imaging and therapeutic moieties to DNA-NSs or DNA-NPs enables high biostability, biocompatibility, and drug loading capabilities, and as a consequence, has markedly catalyzed the rapid growth of this field. This review aims to provide an overview of the recent progress of DNA-NSs and DNA-NPs as theranostic agents, the use of DNA-NSs and DNA-NPs as gene and drug delivery platforms, and a perspective on their clinical translation in the realm of oncology.

The applications of functionalized DNA nanostructures in bioimaging and cancer therapy

Deoxyribonucleic acid (DNA) is a molecular carrier of genetic information that can be fabricated into functional nanomaterials in biochemistry and engineering fields. Those DNA nanostructures, synthesized via Watson-Crick base pairing, show a wide range of attributes along with excellent applicability, precise programmability, and extremely low cytotoxicity in vitro and in vivo. In this review, the applications of functionalized DNA nanostructures in bioimaging and tumor therapy are summarized. We focused on approaches involving DNA origami nanostructures due to their widespread use in previous and current reports. Non-DNA origami nanostructures such as DNA tetrahedrons are also covered. Finally, the remaining challenges and perspectives regarding DNA nanostructures in the biomedical arena are discussed.

Erythrocyte membrane nano-capsules: biomimetic delivery and controlled release of photothermal-photochemical coupling agents for cancer cell therapy

Photothermal therapy (PTT), which involves an increase in temperature triggered only by light signals at tumor sites to remove cancer cells, has been considered an attractive strategy in cancer therapy. Nevertheless, the in vivo applications of photosensitizer-based PTT are limited due to the poor biocompatibility of photothermal agents. Employing red blood cell (RBC) membranes to encapsulate photothermal agents can solve this issue, but the extra surface coating will suppress heat dissipation, which is unfavorable for the subsequent treatment. Herein, biomimetic nano-capsules have been fabricated for light signal-activated cancer therapy by encapsulating photocatalyst titanium dioxide colloid and photothermal agent gold nanorods (Au NRs) in erythrocyte membrane vesicles. The fabricated Au/TiO2@RBC nano-capsules can achieve the controlled release of Au NRs upon the photocatalytic degradation of their surface cell membrane coatings, and generate therapeutic signals after the released Au NRs are irradiated by an NIR laser. Meanwhile, the reactive oxygen species (ROS) produced by photocatalysis are helpful for killing tumor cells photodynamically. Thus, the biomimetic nano-capsules prepared herein will contribute to the research and development in cancer cell therapy.

Gene Therapy Based on Nucleic Acid Nanostructure

During the past decades, nucleic acids have been employed for the construction of versatile nanostructures with well-defined shapes and sizes. Owing to the remarkable programmability, addressability, and biocompatibility, nucleic acid nanostructures are extensively applied in biomedical researches, such as bioimaging, biosensing, and drug delivery. In particular, nucleic acid nanostructures can act as promising candidates for the delivery of gene-related nucleic acid drugs based on the inherent homology. In this review, the recent progress in the design of multifunctional nucleic acid nanocarriers for gene therapy through antisense, RNA interference, gene editing, and gene expression is summarized. Furthermore, the challenges and future opportunities of nucleic acid nanotechnology in biomedical applications will be discussed.

Challenges and Perspectives of DNA Nanostructures in Biomedicine

DNA nanotechnology holds substantial promise for future biomedical engineering and the development of novel therapies and diagnostic assays. The subnanometer-level addressability of DNA nanostructures allows for their precise and tailored modification with numerous chemical and biological entities, which makes them fit to serve as accurate diagnostic tools and multifunctional carriers for targeted drug delivery. The absolute control over shape, size, and function enables the fabrication of tailored and dynamic devices, such as DNA nanorobots that can execute programmed tasks and react to various external stimuli. Even though several studies have demonstrated the successful operation of various biomedical DNA nanostructures both in vitro and in vivo, major obstacles remain on the path to real-world applications of DNA-based nanomedicine. Here, we summarize the current status of the field and the main implementations of biomedical DNA nanostructures. In particular, we focus on open challenges and untackled issues and discuss possible solutions.

Energy-converting biomaterials for cancer therapy: Category, efficiency, and biosafety

Energy-converting biomaterials (ECBs)-mediated cancer-therapeutic modalities have been extensively explored, which have achieved remarkable benefits to overwhelm the obstacles of traditional cancer-treatment modalities. Energy-driven cancer-therapeutic modalities feature their distinctive merits, including noninvasiveness, low mammalian toxicity, adequate therapeutic outcome, and optimistical synergistic therapeutics. In this advanced review, the prevailing mainstream ECBs can be divided into two sections: Reactive oxygen species (ROS)-associated energy-converting biomaterials (ROS-ECBs) and hyperthermia-related energy-converting biomaterials (H-ECBs). On the one hand, ROS-ECBs can transfer exogenous or endogenous energy (such as light, radiation, ultrasound, or chemical) to generate and release highly toxic ROS for inducing tumor cell apoptosis/necrosis, including photo-driven ROS-ECBs for photodynamic therapy, radiation-driven ROS-ECBs for radiotherapy, ultrasound-driven ROS-ECBs for sonodynamic therapy, and chemical-driven ROS-ECBs for chemodynamic therapy. On the other hand, H-ECBs could translate the external energy (such as light and magnetic) into heat for killing tumor cells, including photo-converted H-ECBs for photothermal therapy and magnetic-converted H-ECBs for magnetic hyperthermia therapy. Additionally, the biosafety issues of ECBs are expounded preliminarily, guaranteeing the ever-stringent requirements of clinical translation. Finally, we discussed the prospects and facing challenges for constructing the new-generation ECBs for establishing intriguing energy-driven cancer-therapeutic modalities. This article is categorized under: Nanotechnology Approaches to Biology >Nanoscale Systems in Biology.

Smart Gold Nanostructures for Light Mediated Cancer Theranostics: Combining Optical Diagnostics with Photothermal Therapy

Nanotheranostics, which combines optical multiplexed disease detection with therapeutic monitoring in a single modality, has the potential to propel the field of nanomedicine toward genuine personalized medicine. Currently employed mainstream modalities using gold nanoparticles (AuNPs) in diagnosis and treatment are limited by a lack of specificity and potential issues associated with systemic toxicity. Light-mediated nanotheranostics offers a relatively non-invasive alternative for cancer diagnosis and treatment by using AuNPs of specific shapes and sizes that absorb near infrared (NIR) light, inducing plasmon resonance for enhanced tumor detection and generating localized heat for tumor ablation. Over the last decade, significant progress has been made in the field of nanotheranostics, however the main biological and translational barriers to nanotheranostics leading to a new paradigm in anti-cancer nanomedicine stem from the molecular complexities of cancer and an incomplete mechanistic understanding of utilization of Au-NPs in living systems. This work provides a comprehensive overview on the biological, physical and translational barriers facing the development of nanotheranostics. It will also summarise the recent advances in engineering specific AuNPs, their unique characteristics and, importantly, tunability to achieve the desired optical/photothermal properties.

Application of DNA nanodevices for biosensing

Deoxyribonucleic acid (DNA), the carrier of genetic information in living life, is an essential biomacromolecule in almost all living systems. DNA has advantages including, programmability, predictability, high rigidity, and stability. Through self-assembly or combination with other nanomaterials (such as gold nanoparticles, graphene oxides, quantum dots, and polymers), DNA can be applied to construct specific, stable, biocompatible, and functional nanodevices. DNA nanodevices have made greater contributions in a plethora of fields. In this review, we discuss the recent progress of DNA nanodevices in molecular detection and analysis. Meanwhile, we prospect the development of various DNA devices in biological analysis, clinical diagnosis and biomedical research.

A Genome-Editing Nanomachine Constructed with a Clustered Regularly Interspaced Short Palindromic Repeats System and Activated by Near-Infrared Illumination

The RNA-guided CRISPR/Cas9 system is a powerful genome-editing technology with broad applications. Improving delivery efficiency and controllable activity of the CRISPR/Cas9 system is an area of intense research. We report the design, construction, and application of a CRISPR/Cas9 nanomachine (LACM), activated by a near-infrared (NIR) laser, which enables efficient delivery of single-guide RNA (sgRNA) into living cells and achieves controlled release of the sgRNA for the CRISPR/Cas9 activity. The LACM was constructed using a gold nanorod (AuNR) as a carrier that was decorated with dozens of protector DNAs stably hybridizing with the target binding domain of sgRNA. The DNA assembly on the AuNR protected the sgRNA. Irradiation with a NIR laser generated heat on the AuNR, resulting in controlled release of sgRNA, which guided the CRISPR/Cas9 genome editing. Successful editing of the EGFP and EMX1 genes in A549 and HEK293T cells, as well as knocking down of the PLK1 gene to induce apoptosis of the target cells, highlights the promising potential of the LACM for diverse applications.

Biological Assembly of Modular Protein Building Blocks as Sensing, Delivery, and Therapeutic Agents

Nature has evolved a wide range of strategies to create self-assembled protein nanostructures with structurally defined architectures that serve a myriad of highly specialized biological functions. With the advent of biological tools for site-specific protein modifications and de novo protein design, a wide range of customized protein nanocarriers have been created using both natural and synthetic biological building blocks to mimic these native designs for targeted biomedical applications. In this review, different design frameworks and synthetic decoration strategies for achieving these functional protein nanostructures are summarized. Key attributes of these designer protein nanostructures, their unique functions, and their impact on biosensing and therapeutic applications are discussed.

A Review on Cancer Therapy Based on the Photothermal Effect of Gold Nanorod

Background:

Cancer causes millions of deaths and huge economic losses every year. The currently practiced methods for cancer therapy have many defects, such as side effects, low curate rate, and discomfort for patients.

Objective:

Herein, we summarize the applications of gold nanorods (AuNRs) in cancer therapy based on their photothermal effect-the conversion of light into local heat under irradiation.

Methods:

The recent advances in the synthesis and regulation of AuNRs, and facile surface functionalization further facilitate their use in cancer treatment. For cancer therapy, AuNRs need to be modified or coated with biocompatible molecules (e.g. polyethylene glycol) and materials (e.g. silicon) to reduce the cytotoxicity and increase their biocompatibility, stability, and retention time in the bloodstream. The accumulation of AuNRs in cancerous cells and tissues is due to the high leakage in tumors or the specific interaction between the cell surface and functional molecules on AuNRs such as antibodies, aptamers, and receptors.

Results:

AuNRs are employed not only as therapeutics to ablate tumors solely based on the heat produced under laser that could denature protein and activate the apoptotic pathway, but also as synergistic therapies combined with photodynamic therapy, chemotherapy, and gene therapy to kill cancer more efficiently. More importantly, other materials like TiO2, graphene oxide, and silicon, etc. are incorporated on the AuNR surface for multimodal cancer treatment with high drug loadings and improved cancer-killing efficiency. To highlight their applications in cancer treatment, examples of therapeutic effects both in vitro and in vivo are presented.

Conclusion:

AuNRs have potential applications for clinical cancer therapy.

Hybrid material of structural DNA with inorganic compound: synthesis, applications, and perspective

Owing to its precise manipulation in nanoscale, DNA as a genetic code becomes a promising and generic material in lots of nanotechnological outstanding exploitations. The nanoscale assembly of nucleic acids in aqueous solution has showed very remarkable capability that is not achievable from any other material resources. In the meantime, their striking role played by effective intracellular interactions have been identified, making these more attractive for a variety of biological applications. Lately, a number of interesting attempts have been made to augment their marvelous diagnostic and therapeutic capabilities, as being integrated with inorganic compounds involving gold, iron oxide, quantum dot, upconversion, etc. It was profoundly studied how structural DNA-inorganic hybrid materials have complemented with each other in a synergistic way for better-graded biological performances. Such hybrid materials consisting of both structural DNAs and inorganics are gradually receiving much attention as a practical and future-oriented material substitute. However, any special review articles highlighting the significant and innovative materials have yet to be published. At the first time, we here demonstrate novel hybrid complexes made of structural DNAs and inorganics for some practical applications.

Self-Assembled and Self-Monitored Sorafenib/Indocyanine Green Nanodrug with Synergistic Antitumor Activity Mediated by Hyperthermia and Reactive Oxygen Species-Induced Apoptosis

Liver cancer is a leading cause of cancer morbidity and mortality worldwide, especially in China. Sorafenib (SRF) is currently the most commonly used systemic agent against advanced hepatocellular carcinoma (HCC), which is the most common type of liver cancer. However, HCC patients have only limited benefit and suffer a serious side effect from SRF. Therefore, new approaches are urgently needed to improve the therapeutic effectiveness of SRF and reduce its side effect. In our current study, we developed a self-imaging and self-delivered nanodrug with SRF and indocyanine (ICG) to improve the therapeutic effect of sorafenib against HCC. With the π-π stacking effect between SRF and ICG, a one-step nanoprecipitation method was designed to obtain the SRF/ICG nanoparticles (SINP) via self-assembly. Pluronic F127 was used to shield the SINP to further improve the stability in an aqueous environment. The stability, photothermal effect, cell uptake, ROS production, cytotoxicity, tumor imaging, and tumor-targeting and tumor-killing efficacy of the SINP were evaluated in vitro and in vivo by using an HCC cell line Huh7 and its xenograft tumor model. We found that our designed SINP showed monodisperse stability and efficient photothermal effect both in vitro and in vivo. SINP could rapidly enter Huh7 cells and achieve potent cytotoxicity under near-infrared (NIR) laser irradiation partly by producing a great amount of reactive oxygen species (ROS). SINP had significantly improved stability and blood half-life, and could specifically target tumor via the enhanced permeability and retention (EPR) effect in vivo. In addition, SINP showed improved cytotoxicity in both subcutaneous and orthotopic HCC implantation models in vivo. Overall, this rationally designed sorafenib delivery system with a very high loading capacity (33%) has considerably improved antitumor efficiency in vitro and could completely eliminate subcutaneous tumors without any regrowth in vivo. In conclusion, our self-imaging and self-delivered nanodrug could improve the efficacy of SRF and might be a potential therapy for HCC patients.

Rationally Designed DNA-Origami Nanomaterials for Drug Delivery In Vivo

The recent decades have seen a surge of new nanomaterials designed for efficient drug delivery. DNA nanotechnology has been developed to construct sophisticated 3D nanostructures and artificial molecular devices that can be operated at the nanoscale, giving rise to a variety of programmable functions and fascinating applications. In particular, DNA-origami nanostructures feature rationally designed geometries and precise spatial addressability, as well as marked biocompatibility, thus providing a promising candidate for drug delivery. Here, the recent successful efforts to employ self-assembled DNA-origami nanostructures as drug-delivery vehicles are summarized. The remaining challenges and open opportunities are also discussed.

Tumor Microenvironment-Responsive Nanoshuttles with Sodium Citrate Modification for Hierarchical Targeting and Improved Tumor Theranostics

Enhancement of permeability and the retention effect is one of the main pathways for the accumulation of nanomaterials in tumor sites, but poor cellular internalization and rapid clearance of nanomaterials always hamper the efficacy of imaging diagnosis and treatment. With the consideration of both high tumor accumulation and cellular internalization, positively charged nanomaterials can adhere to the tumor cell membrane by an electrostatic force, which is conducive to cellular internalization, but they are easily recognized and cleared during blood circulation. However, negatively charged nanomaterials show an enhanced stealth-like effect and possess a long blood circulation time, which is conducive to tumor accumulation. Therefore, in this work, on the basis of the shielding effect of citrate ions to positive charge and the protonation under an acidic tumor microenvironment, pH-sensitive sodium citrate-modified polyaniline nanoshuttles (NSs) with negative charge during blood circulation but positive charge in tumor sites are designed. With this hierarchical targeting strategy, the blood circulation half-life increases from 4.35 to 7.33 h, and the retention rate of NSs in tumors increases from 5.29 to 8.57% ID/g. Because the retention rate of NSs is increased, the magnetic resonance imaging resolution and signal intensity are significantly improved. A synergistic treatment of tumors is further achieved by means of photothermal therapy with laser irradiation and chemotherapy via heat-stimulated drug release.

Rationally designed DNA-based nanocarriers

Nanomaterials employed for enhanced drug delivery and therapeutic effects have been extensively investigated in the past decade. The outcome of current anticancer treatments based on conventional nanoparticles is suboptimal, due to the lack of biocompatibility, the deficient tumor targeting, the limited drug accumulation in the diseased region, etc. Alternatively, DNA-based nanocarriers have emerged as a novel and versatile platform to integrate the advantages of nanotechnologies and biological sciences, which shows great promise in addressing the key issues for biomedical studies. Rather than a genetic information carrier, DNA molecules can work as building blocks to fabricate programmable and bio-functional nanostructures based on Watson Crick base-pairing rules. The DNA-based materials have demonstrated unique properties, such as uniform sizes and shapes, pre-designable and programmable nanostructures, site-specific surface functionality and excellent biocompatibility. These intrigue features allow DNA nanostructures to carry functional moieties to realize precise tumor recognition, customized therapeutic functions and stimuli-responsive drug release, making them highly attractive in many aspects of cancer treatment. In this review, we focus on the recent progress in DNA-based self-assembled materials for the biomedical applications, such as molecular imaging, drug delivery for in vitro or in vivo cancer treatments. We introduce the general strategies and essential requirements for fabricating DNA-based nanocarriers. We summarize the advances of DNA-based nanocarriers according to their functionalities and structural properties for cancer diagnosis and therapy. Finally, we discuss the challenges and future perspectives regarding the detailed in vivo parameters of DNA materials and the design of intelligent DNA nanomedicine for individualized cancer therapy.