Theranostic Gold Nanomicelles made from Biocompatible Comb-like Polymers for Thermochemotherapy and Multifunctional Imaging with Rapid Clearance

Chitosan Grafted with Thermoresponsive Poly(di(ethylene glycol) Methyl Ether Methacrylate) for Cell Culture Applications

Chitosan is a polysaccharide extracted from animal sources such as crab and shrimp shells. In this work, chitosan films were modified by grafting them with a thermoresponsive polymer, poly(di(ethylene glycol) methyl ether methacrylate) (PMEO₂MA). The films were modified to introduce functional groups useful as reversible addition-fragmentation chain transfer (RAFT) agents. PMEO₂MA chains were then grown from the films via RAFT polymerization, making the chitosan films thermoresponsive. The degree of substitution of the chitosan-based RAFT agent and the amount of monomer added in the grafting reaction were varied to control the length of the grafted PMEO₂MA chain segments. The chains were cleaved from the film substrates for characterization using ¹H NMR and a gel permeation chromatography analysis. Temperature-dependent contact angle measurements were used to demonstrate that the hydrophilic-hydrophobic nature of the film surface varied with temperature. Due to the enhanced hydrophobic character of PMEO₂MA above its lower critical solution temperature (LCST), the ability of PMEO₂MA-grafted chitosan films to serve as a substrate for cell growth at 37 °C (incubation temperature) was tested. Interactions with cells (fibroblasts, macrophages, and corneal epithelial cells) were assessed. The modified chitosan films supported cell viability and proliferation. As the temperature is lowered to 4 °C (refrigeration temperature, below the LCST), the grafted chitosan films become less hydrophobic, and cell adhesion should decrease, facilitating their removal from the surface. Our results indicated that the cells were detached from the films following a short incubation period at 4 °C, were viable, and retained their ability to proliferate.

Antibacterial Nanomaterials: Mechanisms, Impacts on Antimicrobial Resistance and Design Principles

Antimicrobial resistance (AMR) is one of the biggest threats to the environment and health. AMR rapidly invalidates conventional antibiotics, and antimicrobial nanomaterials have been increasingly explored as alternatives. Interestingly, several antimicrobial nanomaterials show AMR-independent antimicrobial effects without detectable new resistance and have therefore been suggested to prevent AMR evolution. In contrast, some are found to trigger the evolution of AMR. Given these seemingly conflicting findings, a timely discussion of the two faces of antimicrobial nanomaterials is urgently needed. This review systematically compares the killing mechanisms and structure-activity relationships of antibiotics and antimicrobial nanomaterials. We then focus on nano-microbe interactions to elucidate the impacts of molecular initiating events on AMR evolution. Finally, we provide an outlook on future antimicrobial nanomaterials and propose design principles for the prevention of AMR evolution.

Advances in Single-component inorganic nanostructures for photoacoustic imaging guided photothermal therapy

Phototheranostic based on photothermal therapy (PTT) and photoacoustic imaging (PAI), as one of avant-garde medical techniques, have sparked growing attention because it allows noninvasive, deeply penetrative, and highly selective and effective therapy. Among a variety of phototheranostic nanoagents, single-component inorganic nanostructures are found to be novel and attractive PAI and PTT combined nanotheranostic agents and received tremendous attention, which not only exhibit structural controllability, high tunability in physiochemical properties, size-dependent optical properties, high reproducibility, simple composition, easy functionalization, and simple synthesis process, but also can be endowed with multiple therapeutic and imaging functions, realizing the superior therapy result along with bringing less foreign materials into body, reducing systemic side effects and improving the bioavailability. In this review, according to their synthetic components, conventional single-component inorganic nanostructures are divided into metallic nanostructures, metal dichalcogenides, metal oxides, carbon based nanostructures, upconversion nanoparticles (UCNPs), metal organic frameworks (MOFs), MXenes, graphdiyne and other nanostructures. On the basis of this category, their detailed applications in PAI guide PTT of tumor treatment are systematically reviewed, including synthesis strategies, corresponding performances, and cancer diagnosis and therapeutic efficacy. Before these, the factors to influence on photothermal effect and the principle of in vivo PAI are briefly presented. Finally, we also comprehensively and thoroughly discussed the limitation, potential barriers, future perspectives for research and clinical translation of this single-component inorganic nanoagent in biomedical therapeutics.

Polydopamine-doped supramolecular chiral hydrogels for postoperative tumor recurrence inhibition and simultaneously enhanced wound repair

Cancer recurrence remains a major challenge after primary tumor excision, and the inflammation of tumor-caused wounds can hinder wound healing and potentially promote tumor growth. Herein, a chiral L-phenylalanine-based (LPFEG) supramolecular hydrogel system encapsulated with polydopamine nanoparticles (PDA-NPs) has been developed in order to prevent tumor relapse after surgery and promote wound repair. PDA-NPs allow for near-infrared (NIR) light-triggered photothermal therapy, especially, it can scavenge free radicals in the surgical wound. LPFEG can mimic native extracellular matrix (ECM) structure to create a chiral microenvironment that enhances fibroblast adhesion, proliferation, and new tissue regeneration. With anticancer drug doxorubicin (DOX) loaded into the composite hydrogel, the antitumor effect is significantly enhanced by the integration of chemo-photothermal therapy both in vitro and in vivo. The PDA-based chiral supramolecular composite hydrogel as an effective postoperative adjuvant possesses promising applicable prospects in inhibiting tumor recurrence and accelerating wound healing after operation. STATEMENT OF SIGNIFICANCE: After primary tumor excision, cancer recurrence remains a severe concern, and the inflammation induced by tumor-related wounds can delay wound healing. Herein, we designed a chiral L-phenylalanine-based (LPFEG) supramolecular hydrogel platform that was co-assembled with polydopamine nanoparticles (PDA-NPs). Among them, PDA-NPs can offer photothermal therapy and scavenge free radicals in surgical wounds. LPFEG can create a chiral microenvironment that promotes fibroblast adhesion, proliferation, and new tissue regeneration. Furthermore, with anticancer drug doxorubicin (DOX) loaded into the composite hydrogel, the antitumor effect is considerably boosted. Therefore, the PDA-based chiral supramolecular hydrogel shows high application potential as a postoperative adjuvant in preventing tumor relapse as well as accelerating wound healing after surgery.

Ultrasmall-in-Nano: Why Size Matters

Gold nanoparticles (AuNPs) are continuing to gain popularity in the field of nanotechnology. New methods are continuously being developed to tune the particles’ physicochemical properties, resulting in control over their biological fate and applicability to in vivo diagnostics and therapy. This review focuses on the effects of varying particle size on optical properties, opsonization, cellular internalization, renal clearance, biodistribution, tumor accumulation, and toxicity. We review the common methods of synthesizing ultrasmall AuNPs, as well as the emerging constructs termed ultrasmall-in-nano—an approach which promises to provide the desirable properties from both ends of the AuNP size range. We review the various applications and outcomes of ultrasmall-in-nano constructs in vitro and in vivo.

Novel Glutathione Activated Smart Probe for Photoacoustic Imaging, Photothermal Therapy, and Safe Postsurgery Treatment

Preventing tumor recurrence is the most important target for cancer treatment. However, the current effective and advanced technology relies on the use of near-infrared region (NIR), and the equipment of NIR-I and NIR-II fluorescence imaging technique-based fluorescent-guided surgery is expensive and complicated to operate. Here, we report a safe and effective strategy of an organic-inorganic hybrid gold nanoparticle-based novel smart probe (Au@PDA-ss-PEGm NPs) which is appropriate for photoacoustic imaging (PAI) and plasmonic photothermal therapy (PPTT) of tumors in vivo. After intravenous injection, the probe would be transported to the tumor to penetrate the cellular membrane. Then the disulfide bond on the probe surface would be broken with the help of a high concentration of glutathione in the tumor cell. The remaining Au@PDA NPs would aggregate to form plasmonic nanoclusters and exhibit a notable plasmon coupling enhanced photothermal (PCEPT) effect. Besides, the results further proved its good biosafety and pharmacokinetic characteristics in vivo and, more important, a short time exposure under 808 nm laser after surgical removal of the tumor, which would be effective to prevent tumor recurrence and bring dawn to the high-efficiency treatment of tumors.

Degradable Magnetic Nanoplatform with Hydroxide Ions Triggered Photoacoustic, MR Imaging, and Photothermal Conversion for Precise Cancer Theranostic

Theranostic agents based on inorganic nanomaterials are still suffered from the nonbiodegradable substances with long-term retention in body and unavoidable biological toxicity, as well as nonspecificity biodistribution with potential damage toward normal tissues. Here, we develop magnetic ions (Fe^III, Fe^II, Gd^III, Mn^II, and Mn^III) coordinated nanoplatform (MICN) with framework structure and modify them with PEG (MICN-PEG). Notably, MICN-PEG demonstrates hydroxide ions (OH^-) triggered the structure collapse along with responsive near-infrared photoacoustic (PA) signal, magnetic resonance imaging (MRI), and photothermal therapy (PTT) performances. Thereby, MICN-PEG is able to remain stable in tumors and exert excellent PA/MRI and PTT effects for multimodal imaging-guided cancer treatment. In contrast, MICN-PEG is gradually collapsed in normal tissues, resulting in the significant improvement of imaging accuracy and treatment specificity. MICN-PEG is gradually cleared after administration, minimizing concerns about the long-term toxicity.

Bacteria eat nanoprobes for aggregation-enhanced imaging and killing diverse microorganisms

Currently optical-based techniques for in vivo microbial population imaging are limited by low imaging depth and highly light-scattering tissue; and moreover, are generally effective against only one specific group of bacteria. Here, we introduce an imaging and therapy strategy, in which different bacteria actively eat the glucose polymer (GP)-modified gold nanoparticles through ATP-binding cassette (ABC) transporter pathway, followed by laser irradiation-mediated aggregation in the bacterial cells. As a result, the aggregates display ~15.2-fold enhancement in photoacoustic signals and ~3.0-fold enhancement in antibacterial rate compared with non-aggregated counterparts. Significantly, the developed strategy allows ultrasensitive imaging of bacteria in vivo as low ~10⁵ colony-forming unit (CFU), which is around two orders of magnitude lower than most optical contrast agents. We further demonstrate the developed strategy enables the detection of ~10⁷ CFU bacteria residing within tumour or gut. This technique enables visualization and treatment of diverse bacteria, setting the crucial step forward the study of microbial ecosystem.

The authors demonstrate a strategy for bacterial uptake of gold nanoparticles modified with glucose polymer. The particles aggregate in the bacterial cells upon laser irradiation, resulting in enhanced photoacoustic signal and antibacterial activity, enabling sensitive imaging of bacteria in vivo.

Structure-dilute solution property relationships of comb-like macromolecules in a good solvent

The structural characterization of branched polymers still poses experimental challenges despite their technological potential. This lack of clarity is egregious in linear low-density polyethylene (LLDPE), a common industrial plastic. Here, we design a coarse-grain, implicit solvent molecular dynamics model for LLDPE in 1,2,4-trichlorobenzene, a canonical good solvent, that replicates all-atom simulations and experiments. We employ this model to test the relationship between the contraction factors, the ratios of branched to linear dilute solution properties. In particular, we relate the contraction factor of the radius of gyration to that of the intrinsic viscosity and the hydrodynamic radius. The contraction exponents are constant as we vary branch length and spacing in contrast to theoretical expectations. We use this observation to develop a general theory for the dilute solution properties of linear polymers with linear side-chain branches, comb-like macromolecules, in a good solvent and validate the theory by generating master curves for LLDPE.

Acoustics at the nanoscale (nanoacoustics): A comprehensive literature review.: Part II: Nanoacoustics for biomedical imaging and therapy

In the past decade, acoustics at the nanoscale (i.e., nanoacoustics) has evolved rapidly with continuous and substantial expansion of capabilities and refinement of techniques. Motivated by research innovations in the last decade, for the first time, recent advancements of acoustics-associated nanomaterials/nanostructures and nanodevices for different applications are outlined in this comprehensive review, which is written in two parts. As part II of this two-part review, this paper concentrates on nanoacoustics in biomedical imaging and therapy applications, including molecular ultrasound imaging, photoacoustic imaging, ultrasound-mediated drug delivery and therapy, and photoacoustic drug delivery and therapy. Firstly, the recent developments of nanosized ultrasound and photoacoustic contrast agents as well as their various imaging applications are examined. Secondly, different types of nanomaterials/nanostructures as nanocarriers for ultrasound and photoacoustic therapies are discussed. Finally, a discussion of challenges and future research directions are provided for nanoacoustics in medical imaging and therapy.

Tumor microenvironment-responsive dynamic inorganic nanoassemblies for cancer imaging and treatment

Dynamic inorganic nanoassemblies (DINAs) have emerged as smart nanomedicine platforms with promising potential for bioimaging and targeted drug delivery. In this review, we keep abreast of the advances in development of tumor microenvironment (TME)-responsive DINAs to meet the challenges associated with precise cancer therapy. TME-responsive DINAs are designed to achieve precise switches of structures/functions in response to TME-specific stimuli including reactive oxygen species (ROS), reduced pH and hypoxia, so as to enhance the tumor accumulation of nanoassemblies, overcome the biological barriers during intratumoral penentration of therapeutics, and achieve tumor-specific imaging and therapy. This progress report will summarize various types of recently reported smart DINAs for TME-responsive tumor imaging and therapy. Their future development towards potential clinical translation will also be discussed.

Gold nanotheranostics: future emblem of cancer nanomedicine

Cancer nanotheranostics aims at providing alternative approaches to traditional cancer diagnostics and therapies. In this context, plasmonic nanostructures especially gold nanostructures are intensely explored due to their tunable shape, size and surface plasmon resonance (SPR), better photothermal therapy (PTT) and photodynamic therapy (PDT) ability, effective contrast enhancing ability in Magnetic Resonance imaging (MRI) and Computed Tomography (CT) scan. Despite rapid breakthroughs in gold nanostructures based theranostics of cancer, the translation of gold nanostructures from bench side to human applications is still questionable. The major obstacles that have been facing by nanotheranostics are specific targeting, poor resolution and photoinstability during PTT etc. In this regard, various encouraging studies have been carried out recently to overcome few of these obstacles. Use of gold nanocomposites also overcomes the limitations of gold nanostructure probes and emerged as good nanotheranostic probe. Hence, the present article discusses the advances in gold nanostructures based cancer theranostics and mainly emphasizes on the importance of gold nanocomposites which have been designed to decipher the past questions and limitations of in vivo gold nanotheranostics.

Recent advances in nanosized metal organic frameworks for drug delivery and tumor therapy

Metal organic-frameworks (MOFs) are novel materials that have attracted increasing attention for applications in a wide range of research, owing to their unique advantages including their small particle size, porous framework structure and high specific surface area. Because of their adjustable size, nanoscale MOFs (nano-MOFs) can be prepared as carriers of biotherapy drugs, thus enabling biotherapeutic applications. Nano-MOFs' metal ion catalytic activity and organic group functional characteristics can be exploited in biological treatments. Furthermore, the applications of nano-MOFs can be broadened by hybridization with other materials to form composites. This review focuses on the preparation and recent advances in nano-MOFs as drug carriers, therapeutic materials and functionalized materials in drug delivery and tumor therapy based on the single/multiple stimulus response of drug release to achieve the targeted therapy, offering a comprehensive reference for drug carrier design. At the end, the current challenges and prospects are discussed to provide significant insight into the design and applications of nano-MOFs in drug delivery and tumor therapy.

Uptake quantification of gold nanoparticles inside of cancer cells using high order image correlation spectroscopy

The application of gold nanoparticles (AuNPs) in cancer therapeutics and diagnostics has recently reached a clinical level. Functional use of the AuNP in theranostics first requires effective uptake into the cells, but accurate quantification of AuNPs cellular uptake in real-time is still a challenge due to the destructive nature of existing characterization methods. The optical imaging-based quantification method is highly desirable. Here, we propose the use of high-order image correlation spectroscopy (HICS) as an optical imaging-based nanoparticle quantification technique. Coupled with dark field microscopy (DFM), a non-destructive and easy quantification method could be achieved. We demonstrate HICS analysis on 80 nm AuNPs coated with cetyltrimethylammonium bromide (CTAB) uptake in HeLa cells to calculate the percentage of aggregate species (dimer) in the total uptake and their relative scattering quantum yield inside the cells, the details of which are not available with other quantification techniques. The total particle uptake kinetics measured were in a reasonable agreement with the literature.

Dual drug-paired polyprodrug nanotheranostics reverse multidrug resistant cancers via mild photothermal-cocktail chemotherapy

Combating multidrug resistance (MDR) of tumors is still challenging for clinical chemotherapy, cocktail chemotherapy (CCT), and currently widely-studied nanodrug-based treatments. Inspired by different MDR-overcoming and antitumor mechanisms of CCT and photothermal therapy (PT), a dual drug-paired polyprodrug nanoparticle (PDCN25-CDDP) was constructed to achieve the combination therapy PT-CCT for reversing MDR and combating multidrug resistant cancers. The PT-CCT treatment can greatly downregulate the P-gp expression level and achieve utmost MDR-reversal and antitumor efficacy by both a cocktail effect of CCT and a synergistic effect of CCT with PT; meanwhile, PT can inhibit the expression of heat shock protein 90 and enhance the thermosensitivity of cancer cells. Upon NIR irradiation, PDCN25-CDDPin vivo produced a selective tumor accumulation effect and relatively deep tumor penetration, as evidenced by fluorescent and photoacoustic imaging and CLSM. The mild PT-CCT treatment completely eradicated MCF-7/ADR and OVCAR-3/DDP tumors without skin damage or tumor recurrence for 30 days, exhibiting synergistic MDR-reversal and superior antitumor efficacy in vivo. Importantly, this work provides an innovative strategy for reversing MDR and combating DOX-resistant breast and CDDP-resistant ovarian cancers.

Surface Modification of Iron Oxide-Based Magnetic Nanoparticles for Cerebral Theranostics: Application and Prospection

Combining diagnosis with therapy, magnetic iron oxide nanoparticles (INOPs) act as an important vehicle for drug delivery. However, poor biocompatibility of INOPs limits their application. To improve the shortcomings, various surface modifications have been developed, including small molecules coatings, polymers coatings, lipid coatings and lipopolymer coatings. These surface modifications facilitate iron nanoparticles to cross the blood-brain-barrier, which is essential for diagnosis and treatments of brain diseases. Here we focus on the characteristics of different coated INOPs and their application in brain disease, particularly gliomas, Alzheimer's disease (AD) and Parkinson's disease (PD). Moreover, we summarize the current progress and expect to provide help for future researches.

Targeted nanocarriers based on iodinated-cyanine dyes as immunomodulators for synergistic phototherapy

Photodynamic therapy (PDT), as one of the most powerful photo-therapeutic strategies for cancer treatment with minimum invasiveness, can effectively damage local tumor cells and significantly induce systemic antitumor immunity. However, current nanotechnology-assisted PDT-immunomodulators have either poor penetration for deep tumors or low singlet oxygen generation. Herein, we construct a novel theranostic nanocarrier (HA-PEG-CyI, HPC) by inducing the self-assembly of PEGylated CyI and attaching the ligand HA to its surface. The prepared HPC can be used as an ideal PDT-immunomodulator for synergistic cancer therapy. CyI is an iodinated-cyanine dye with enhanced singlet oxygen generation ability as well as excellent photo-to-photothermal and near-infrared fluorescence imaging properties. Under 808 nm laser irradiation, the prepared HPC can generate both reactive oxygen species (ROS) and elevate temperature which can subsequently result in apoptosis and necrosis at tumor sites. Moreover, the HPC-induced cell death can generate a series of acute inflammatory reactions, leading to systemic immunity induction and secondary death of tumor cells, which further results in reducing tumor recurrence. In vitro and in vivo results show that HPC can enhance the tumor targeting efficacy, generate ROS efficiently and exhibit a high temperature response under NIR irradiation, which working together can activate immune responses for synergistic phototherapy on tumor cells. Accordingly, the proposed multi-functional HPC nanocarriers represent an important advance in PDT and can be used as a superior cancer treatment strategy with great promise for clinical applications.

Alginate mediated functional aggregation of gold nanoclusters for systemic photothermal therapy and efficient renal clearance

For renal clearable nanoagents, it is challenging to delay the renal clearance to acquire efficient tumor accumulation. Herein, we report sodium alginate (SA) stabilized gold (Au) NCs. The Au NCs are of high biocompatibility and renal clearable. Contributed from the ligands of SA, the half-life (t_1/2) of Au NCs is prolonged to ∼9.3 h, enhancing the tumor accumulation rate to 10.4 %ID/g. In tumor microenvironment (TME), the Au NCs are stimulated to functionally aggregate, which switches on the photothermal effect. Animal experiments prove that Au NCs aggregates are efficient photothermal therapy (PTT) agents for both local treatment of single tumors and systemic treatment of double-tumor models without causing noticeable side effects, confirming the biosecurity of Au NCs and systemic PTT. The switchable strategy of PTT may signify the establishment of a new systemic therapeutic methodology.

Core/Shell PEGS/HA Hybrid Nanoparticle Via Micelle-Coordinated Mineralization for Tumor-Specific Therapy

Nanomicelles, by virtue of their prominent biocompatibility, degradability, and ability to solubilize hydrophobic drugs, have been widely used as the most effective delivery platform for anticancer drugs. However, undesirable drug-loading capacity, unfeasible modification, poor in vivo stability, and intratumoral penetration remain to be addressed. Herein, we introduce a novel core/shell PEGylated poly(glycerol sebacate) (PEGS)/hydroxyapatite (HA) hybrid nanomicelle based on a unique triblock PEGS substrate with functional carboxyls in terminals and free hydroxyls as pendant groups. The hydrophobic doxorubicin (DOX) can be controllably encapsulated in the core of nanomicelles via hydrogen bonding, and ensuing in situ mineralization of HA occurs as a shell layer with the electrostatic effect between the carboxylate radical (COO^-) and calcium ion (Ca²⁺). Through optimizing the coordination of PEGS nanomicelles and HA mineralization, 20-30 nm spherical nanoparticles can be formed with considerable drug loading (0.38 mg DOX/1 mg nanoparticles) and a sensitive pH-responsive release (about 50% release amount at pH 5.6 while <5% release amount at pH 7.4 in 24 h). In further in vitro studies, this PEGS/HA hybrid nanoparticle system exhibits excellent selective tumor inhibitory efficacy, while in in vivo studies, high efficacy of tumor suppression and low incidence of toxicity can be evidenced in a DOX-loaded PEGS/HA group (71.7% decrease in average tumor volume compared to a control group after 15 day hypodermic treatment). The core/shell PEGS/HA nanoparticle coordinated with PEGS nanomicelles and in situ HA mineralization represents high drug-loading capacity, multifunctional possibility, and tumor-selective and responsive release profiles and could offer a highly promising platform for tumor therapy in clinical application.

Plasmonic Nanoassemblies: Tentacles Beat Satellites for Boosting Broadband NIR Plasmon Coupling Providing a Novel Candidate for SERS and Photothermal Therapy

Optical theranostic applications demand near-infrared (NIR) localized surface plasmon resonance (LSPR) and maximized electric field at nanosurfaces and nanojunctions, aiding diagnosis via Raman or optoacoustic imaging, and photothermal-based therapies. To this end, multiple permutations and combinations of plasmonic nanostructures and molecular "glues" or linkers are employed to obtain nanoassemblies, such as nanobranches and core-satellite morphologies. An advanced nanoassembly morphology comprising multiple linear tentacles anchored onto a spherical core is reported here. Importantly, this core-multi-tentacle-nanoassembly (CMT) benefits from numerous plasmonic interactions between multiple 5 nm gold nanoparticles (NPs) forming each tentacle as well as tentacle to core (15 nm) coupling. This results in an intense LSPR across the "biological optical window" of 650-1100 nm. It is shown that the combined interactions are responsible for the broadband LSPR and the intense electric field, otherwise not achievable with core-satellite morphologies. Further the sub 80 nm CMTs boosted NIR-surface-enhanced Raman scattering (SERS), with detection of SERS labels at 47 × 10^-9 m, as well as lower toxicity to noncancerous cell lines (human fibroblast Wi38) than observed for cancerous cell lines (human breast cancer MCF7), presents itself as an attractive candidate for use as biomedical theranostics agents.

Combined-therapeutic strategies synergistically potentiate glioblastoma multiforme treatment via nanotechnology

Glioblastoma multiforme (GBM) is a highly aggressive and devastating brain tumor characterized by poor prognosis and high rates of recurrence. Numerous therapeutic strategies and delivery systems are developed to prolong the survival time. They exhibit enhanced therapeutic effects in animal models, whereas few of them is applied in clinical trials. Taking into account the drug-resistance and high recurrence of GBM, combined-therapeutic strategies are exploited to maximize therapeutic efficacy. The combined therapies demonstrate superior results than those of single therapies against GBM. The co-therapeutic agents, the timing of therapeutic strategies and the delivery systems greatly affect the overall outcomes. Herein, the current advances in combined therapies for glioblastoma via systemic administration are exhibited in this review. And we will discuss the pros and cons of these combined-therapeutic strategies via nanotechnology, and provide the guidance for developing rational delivery systems to optimize treatments against GBM and other malignancies in central nervous system.

Biointerface engineering nanoplatforms for cancer-targeted drug delivery

Over the past decade, nanoparticle-based therapeutic modalities have become promising strategies in cancer therapy. Selective delivery of anticancer drugs to the lesion sites is critical for elimination of the tumor and an improved prognosis. Innovative design and advanced biointerface engineering have promoted the development of various nanocarriers for optimized drug delivery. Keeping in mind the biological framework of the tumor microenvironment, biomembrane-camouflaged nanoplatforms have been a research focus, reflecting their superiority in cancer targeting. In this review, we summarize the development of various biomimetic cell membrane-camouflaged nanoplatforms for cancer-targeted drug delivery, which are classified according to the membranes from different cells. The challenges and opportunities of the advanced biointerface engineering drug delivery nanosystems in cancer therapy are discussed.

Design of highly stabilized nanocomposite inks based on biodegradable polymer-matrix and gold nanoparticles for Inkjet Printing

Nowadays there is a worldwide growing interest in the Inkjet Printing technology owing to its potentially high levels of geometrical complexity, personalization and resolution. There is also social concern about usage, disposal and accumulation of plastic materials. In this work, it is shown that sugar-based biodegradable polyurethane polymers exhibit outstanding properties as polymer-matrix for gold nanoparticles composites. These materials could reach exceptional stabilization levels, and demonstrated potential as novel robust inks for Inkjet based Printing. Furthermore, a physical comparison among different polymers is discussed based on stability and printability experiments to search for the best ink candidate. The University of Seville logo was printed by employing those inks, and the presence of gold was confirmed by ToF-SIMS. This approach has the potential to open new routes and applications for fabrication of enhanced biomedical nanometallic-sensors using stabilized AuNP.

Nanotechnology based therapeutic application in cancer diagnosis and therapy

Due to the lack of early diagnosis, cancer remains as one of the leading cause of human mortality. Inability to translate research into clinical trials and also inability of chemotherapeutics delivery to targeted tumor sites are major drawbacks in cancer therapeutics. With the emergence of nanomedicine, several nanoprobes (conjugated with targeting ligands and chemotherapeutic drugs) are developed. It can interact with biological system and thus sense and monitor the biological events with high efficiency and accuracy along with therapy application. Nanoparticles like gold and iron oxide are frequently used in the computed tomography and magnetic resonance imaging applications, respectively. Moreover, enzymatic activity of gold and iron oxide nanoparticles enables the visible colorimetric diagnostic of cancer cells, whereas, fluorescence property of quantum dots and upconversion nanoparticles helps in in vivo imaging application. Other than this, drug conjugation with nanoparticles also reduces the systemic toxic effect of chemotherapeutic drugs. Due to their several unique intrinsic properties, nanoparticles itself can also be employed as therapeutics in cancer treatment by photothermal therapy (PTT) and photodynamic therapy (PDT). Thus, the main focus of this review is to emphasize on current progress in diagnostic and therapeutic application of nanoprobes in cancer.

Light-activatable dual prodrug polymer nanoparticle for precise synergistic chemotherapy guided by drug-mediated computed tomography imaging

The synergistic efficacy and clinical application of light-responsive polymeric co-delivery systems are severely restricted by uncontrollable/imprecise drug loading, release, and adverse effects caused by the introduction of additional light-responsive molecules or contrast agents when diagnostic imaging is applied to guide therapy. Here, we report the design of a light-activatable dual prodrug polymer nanoparticle (DPP NP) for precise synergistic chemotherapy guided by drug-mediated computed tomography (DMCT) imaging without the introduction of any additional diagnostic imaging agent. DPP NP enables visible light-triggered prodrug polymer backbone cleavage and bioactive Pt(II) release in cancer cell/tumor site; the light-cleaved polymer fragments are further hydrolyzed to produce demethyl cantharidin (DMC). Notably, the drug loading ratio of Pt(IV) and DMC in DPP NP was fixed at an optimal value to achieve maximum synergistic cancer cell killing, which was kept even after cellular uptake, thereby resulting in enhanced synergistic antitumor efficacy both in vitro and in vivo. Because of the high content of the heavy metal Pt in the polymer chain, the spatial/temporal dynamic biodistribution as well as metabolism of DPP NP in vivo can be monitored by Pt DMCT imaging to guide the light irradiation parameters for optimized light-activatable synergistic chemotherapy. Guided by Pt DMCT imaging, DPP NP was able to achieve an improved light-activatable antitumor efficacy, with 75% tumors fully cured and low toxicity. The light-activatable DDP NP system exhibits tremendous potential as precise theranostic nanomedicine. STATEMENT OF SIGNIFICANCE: The synergistic efficacy and clinical application of light-responsive polymeric co-delivery systems are severely restricted by uncontrollable/imprecise drug loading, delivery, and release, as well as adverse effects caused by the introduction of additional light-responsive molecules or contrast agents when diagnostic imaging is applied to guide therapy. Herein, we report the design of a light-activatable dual prodrug polymer nanoparticle (DPP NP) for precise synergistic chemotherapy guided by drug-mediated computed tomography imaging without the introduction of any additional diagnostic imaging agents. Notably, the drug loading ratio of Pt(II) and DMC in DPP NP was fixed at an optimal value to achieve maximum synergistic cancer cell killing, which was kept even after cellular uptake, thereby resulting in enhanced synergistic antitumor efficacy both in vitro and in vivo. The light-activatable DDP NP system exhibits tremendous potential as precise theranostic nanomedicine.

A stimuli-responsive drug release nanoplatform for kidney-specific anti-fibrosis treatment

The renoprotective effects of hypoxia inducible-factor (HIF) activators have been demonstrated by improving renal hypoxia in chronic kidney disease. Cobalt chloride is one of the most widely used HIF activators in biomedicine; however, poor kidney targeting and undesirable side effects greatly limit its clinical applications. Here, we report a novel stimuli-responsive drug release nanoplatform in which glutathione (GSH)-modified Au nanoparticles (GLAuNPs) and Co2+ self-assemble into nanoassemblies (GLAuNPs-Co) through coordination interactions between empty orbitals of Co2+ and lone pairs of GSH. The GLAuNPs, when used as a drug carrier, demonstrated high drug loading capacity and pH-triggered drug release after assembling with Co2+. The acidic environment of lysosomes in renal fibrosis tissues could disassemble GLAuNPs-Co and release Co2+. Moreover, encapsulation of the Co2+ ions in the GLAuNPs greatly lowered the cytotoxicity of Co2+ in kidney tubule cells. Tissue fluorescence imaging showed that GLAuNPs-Co specifically accumulated in the kidneys, especially in the renal proximal tubules. After GLAuNPs-Co was intraperitoneally injected into ureter-obstructed mice, significant attenuation of interstitial fibrosis was exhibited. The beneficial effects can be mainly ascribed to miR-29c expression restored by HIF-α activation. These findings revealed that GLAuNPs-Co have pH-responsive drug release and renal targeting capabilities; thus, they are a promising drug delivery platform for treating kidney disease.

Cytomembrane nanovaccines show therapeutic effects by mimicking tumor cells and antigen presenting cells

Most cancer vaccines are unsuccessful in eliciting clinically relevant effects. Without using exogenous antigens and adoptive cells, we show a concept of utilizing biologically reprogrammed cytomembranes of the fused cells (FCs) derived from dendritic cells (DCs) and cancer cells as tumor vaccines. The fusion of immunologically interrelated two types of cells results in strong expression of the whole tumor antigen complexes and the immunological co-stimulatory molecules on cytomembranes (FMs), allowing the nanoparticle-supported FM (NP@FM) to function like antigen presenting cells (APCs) for T cell immunoactivation. Moreover, tumor-antigen bearing NP@FM can be bio-recognized by DCs to induce DC-mediated T cell immunoactivation. The combination of these two immunoactivation pathways offers powerful antitumor immunoresponse. Through mimicking both APCs and cancer cells, this cytomembrane vaccine strategy can develop various vaccines toward multiple tumor types and provide chances for accommodating diverse functions originating from the supporters.

Gold nanoparticles in chemo-, immuno-, and combined therapy: review [Invited]

Functionalized gold nanoparticles (GNPs) with controlled geometrical and optical properties have been the subject of intense research and biomedical applications. This review summarizes recent data and topical problems in nanomedicine that are related to the use of variously sized, shaped, and structured GNPs. We focus on three topical fields in current nanomedicine: (1) use of GNP-based nanoplatforms for the targeted delivery of anticancer and antimicrobial drugs and of genes; (2) GNP-based cancer immunotherapy; and (3) combined chemo-, immuno-, and phototherapy. We present a summary of the available literature data and a short discussion of future work.

Expandable Immunotherapeutic Nanoplatforms Engineered from Cytomembranes of Hybrid Cells Derived from Cancer and Dendritic Cells

Using the cytomembranes (FMs) of hybrid cells acquired from the fusion of cancer and dendritic cells (DCs), this study offers a biologically derived platform for the combination of immunotherapy and traditional oncotherapy approaches. Due to the immunoactivation implicated in the cellular fusion, FMs can effectively express whole cancer antigens and immunological co-stimulatory molecules for robust immunotherapy. FMs share the tumor's self-targeting character with the parent cancer cells. In bilateral tumor-bearing mouse models, the FM-coated nanophotosensitizer causes durable immunoresponse to inhibit the rebound of primary tumors post-nanophotosensitizer-induced photodynamic therapy (PDT). The FM-induced immunotherapy displays ultrahigh antitumor effects even comparable to that of PDT. On the other hand, PDT toward primary tumors enhances the immunotherapy-caused regression of the irradiation-free distant tumors. Consequently, both the primary and the distant tumors are almost completely eliminated. This tumor-specific immunotherapy-based nanoplatform is potentially expandable to multiple tumor types and readily equipped with diverse functions owing to the flexible nanoparticle options.

Gold nanocluster-loaded hybrid albumin nanoparticles with fluorescence-based optical visualization and photothermal conversion for tumor detection/ablation

Gold nanoclusters (AuNCs) are viewed as effective hyperthermal agents for the treatment of tumors. Whereas AuNCs formed by the agglomeration of several to tens of gold atoms (<1-2 nm) possess significant fluorescence, they have a negligible hyperthermal effect, while AuNCs comprised of spherical gold nanoparticles (AuNPs > a few nanometers) have a marked hyperthermic effect but lose their inherent fluorescence and obstruct the intensity of neighboring fluorescent dyes due to Forster resonance energy transfer (FRET). To achieve both hyperthermia and fluorescence-based optical visualization, we generated hybrid albumin nanoparticles containing AuNCs (~88 nm) comprising AuNPs (~4.5 nm). We generated a series of formulated AuNCs and optimized the size, morphology, NIR absorbance (600-900 nm), hyperthermal activity, and fluorescence spectral characters of the resulting hybrid albumin nanoparticles (AuNCs/BSA-NPs) by considering the interparticle distance between the AuNPs and Cy5.5. Among these, AuNCs/BSA-NPs (formula D) had a strong hyperthermic effect and had well-preserved fluorescence intensity (from the attached Cy5.5) due to localized surface plasmon resonance (LSPR) and a reduction in FRET. These AuNCs/BSA-NPs were able to elevate the surface tumor temperature of HCT116-bearing mice to >50 °C following 808 nm laser irradiation (1.5 W/cm², 10 min), which remarkably suppressed tumor growth (17.8 ± 16.9 mm³vs. PBS and AuNCs/BSA-NPs (formula E): ~1850 and ~1250 mm³, respectively). Also, Cy5.5-modified AuNCs/BSA-NPs (formula D) showed good performance in optical fluorescence imaging of target tumors in HCT116 tumor-bearing mice. Together, our results indicate that the interparticle distance between albumin or Cy5.5 and AuNPs/AuNCs can be optimized to achieve both hyperthermia and fluorescence emission by striking a balance between LSPR and FRET effects. We believe that the AuNC/BSA-NPs formulation presented here can serve as a potential platform for both optically visualizing and treating colon cancers.

Photothermal therapy and photoacoustic imaging via nanotheranostics in fighting cancer

The nonradiative conversion of light energy into heat (photothermal therapy, PTT) or sound energy (photoacoustic imaging, PAI) has been intensively investigated for the treatment and diagnosis of cancer, respectively. By taking advantage of nanocarriers, both imaging and therapeutic functions together with enhanced tumour accumulation have been thoroughly studied to improve the pre-clinical efficiency of PAI and PTT. In this review, we first summarize the development of inorganic and organic nano photothermal transduction agents (PTAs) and strategies for improving the PTT outcomes, including applying appropriate laser dosage, guiding the treatment via imaging techniques, developing PTAs with absorption in the second NIR window, increasing photothermal conversion efficiency (PCE), and also increasing the accumulation of PTAs in tumours. Second, we introduce the advantages of combining PTT with other therapies in cancer treatment. Third, the emerging applications of PAI in cancer-related research are exemplified. Finally, the perspectives and challenges of PTT and PAI for combating cancer, especially regarding their clinical translation, are discussed. We believe that PTT and PAI having noteworthy features would become promising next-generation non-invasive cancer theranostic techniques and improve our ability to combat cancers.

Gold Nanorods-Based Smart Nanoplatforms for Synergic Thermotherapy and Chemotherapy of Tumor Metastasis

The combination therapy of photothermal therapy and chemotherapy as a promising strategy has drawn extensive attention by overcoming the limitations of conventional treatments in tumor therapy. Gold nanorods-based nanoplatforms were herein designed by integrating doxorubicin (DOX)- and polydopamine-coated gold nanorods (GNRs@PDA) for tumor metastasis inhibition and multifunctional drug delivery. The GNRs@PDA-poly(ethylene glycol) (PEG)-DOX nanocomplex showed robust stability and excellent near-infrared (NIR) photothermal conversion efficiency under laser irradiation. The release of loaded DOX from GNRs@PDA-PEG-DOX nanocomposites was improved in tumor microenvironments. Furthermore, the PDA-functionalized GNR nanocomposites were expected to be potential photoacoustic imaging agents for imaging-guided tumor therapy. Upon NIR laser irradiation, the efficiency of tumor inhibition of GNRs@PDA-PEG-DOX is greater than that of the other group in vitro and in vivo, which was confirmed by immunohistochemistry staining, demonstrating a promising strategy for suppression of tumor metastasis and low long-term systemic toxicity. These results illustrated a promising strategy of tailor-made GNRs@PDA-PEG-DOX nanoplatforms for ablation of tumor and suppression of tumor metastasis in clinical application.

Two-Photon Image Tracking of Neural Stem Cells via Iridium Complexes Encapsulated in Polymeric Nanospheres

Iridium(III) complexes have been shown to be promising probes in two-photon imaging to real-time track the transplanted cells in stem-cell-based therapy. Here, we report on polymeric nanocapsules loaded with red phosphorescence dye of bis(2-methyldibenzo[f,h]quinoxaline) (acetylacetonate) iridium(III) (Ir(MDQ)₂acac) with excellent stability created by the double emulsion method. The Ir(MDQ)₂acac nanocapsules present high biocompatibility and an efficient fluorescent labeling rate when incubated with cultured mouse neural stem cells (NSCs). More importantly, the Ir(MDQ)₂acac nanocapsules had both one- and two-photon imaging properties with stable phosphorescence lasting for 72 h. Furthermore, data from in vivo tracking in nude mice demonstrated that the photoluminescence from Ir(MDQ)₂acac nanocapsules in NSCs could be stably monitored for up to 21 days. Our data shed light on the potential clinical application of iridium complexes encapsulated in polymeric nanospheres for two-photon imaging in real-time tracking of the transplanted stem cells.

Photoacoustic Imaging: Contrast Agents and Their Biomedical Applications

Photoacoustic (PA) imaging as a fast-developing imaging technique has great potential in biomedical and clinical applications. It is a noninvasive imaging modality that depends on the light-absorption coefficient of the imaged tissue and the injected PA-imaging contrast agents. Furthermore, PA imaging provides superb contrast, super spatial resolution, and high penetrability and sensitivity to tissue functional characteristics by detecting the acoustic wave to construct PA images. In recent years, a series of PA-imaging contrast agents are developed to improve the PA-imaging performance in biomedical applications. Here, recent progress of PA contrast agents and their biomedical applications are outlined. PA contrast agents are classified according to their components and function, and gold nanocrystals, gold-nanocrystal assembly, transition-metal chalcogenides/MXene-based nanomaterials, carbon-based nanomaterials, other inorganic imaging agents, small organic molecules, semiconducting polymer nanoparticles, and nonlinear PA-imaging contrast agents are discussed. The applications of PA contrast agents as biosensors (in the sensing of metal ions, pH, enzymes, temperature, hypoxia, reactive oxygen species, and reactive nitrogen species) and in bioimaging (lymph nodes, vasculature, tumors, and brain tissue) are discussed in detail. Finally, an outlook on the future research and investigation of PA-imaging contrast agents and their significance in biomedical research is presented.

Light-Triggered Covalent Coupling of Gold Nanoparticles for Photothermal Cancer Therapy

Manipulating the cross-coupling of gold nanoparticles (AuNPs) to maximize the photothermal effect is a promising strategy for cancer therapy. Here, by taking advantage of the well-known tetrazole/alkene photoclick chemistry, we have demonstrated for the first time that small AuNPs (23 nm) decorated with both 2,5-diphenyltetrazole and methacrylic acid on their surfaces can form covalently crosslinked aggregates upon laser irradiation (λ=405 nm). In vitro studies indicated that the light-triggered assembling shifted the surface plasmon resonance of AuNPs significantly to near-infrared (NIR) regions, which as a consequence effectively enhanced the efficacy of photothermal therapy for 4T1 breast cancer cells. We thus believe that this new light-triggered cross-coupling approach might offer a valuable tool for cancer treatment.

Size effect of mesoporous organosilica nanoparticles on tumor penetration and accumulation

The size effect of mesoporous organosilica nanoparticles (MONs) on tumor penetration and accumulation remains poorly understood, which strongly affects the tumor therapeutic efficacy.

Vehicle-saving theranostic probes based on hydrophobic iron oxide nanoclusters using doxorubicin as a phase transfer agent for MRI and chemotherapy

A simple approach for constructing vehicle-saving theranostic nanobeads for MRI and chemotherapy is developed by using doxorubicin for phase transfer of iron oxide nanoclusters.

External stimulus responsive inorganic nanomaterials for cancer theranostics

Cancer is a highly intelligent system of cells, that works together with the body to thrive and subsequently overwhelm the host in order for its survival. Therefore, treatment regimens should be equally competent to outsmart these cells. Unfortunately, it is not the case with current therapeutic practices, the reason why it is still one of the most deadly adversaries and an imposing challenge to healthcare practitioners and researchers alike. With rapid nanotechnological interventions in the medical arena, the amalgamation of diagnostic and therapeutic functionalities into a single platform, theranostics provides a never before experienced hope of enhancing diagnostic accuracy and therapeutic efficiency. Additionally, the ability of these nanotheranostic agents to perform their actions on-demand, i.e. can be controlled by external stimulus such as light, magnetic field, sound waves and radiation has cemented their position as next generation anti-cancer candidates. Numerous reports exist of such stimuli-responsive theranostic nanomaterials against cancer, but few have broken through to clinical trials, let alone clinical practice. This review sheds light on the pros and cons of a few such theranostic nanomaterials, especially inorganic nanomaterials which do not require any additional chemical moieties to initiate the stimulus. The review will primarily focus on preclinical and clinical trial approved theranostic agents alone, describing their success or failure in the respective stages.

Facile fabrication of highly photothermal-effective albumin-assisted gold nanoclusters for treating breast cancer

Gold nanoclusters (AuNCs) have been considered to be a promising candidate for hyperthermia-based anticancer therapy. Herein, we introduce albumin-assisted AuNCs composed of small gold nanoparticles (AuNPs, <6 nm) assembled with strands of polyallylamine (PAH), which exhibited strong surface plasmon resonance upon near-infrared (NIR, ∼808 nm) laser irradiation and good in vivo stability. Our albumin-assisted PAH-AuNCs (BSA/PAH-AuNCs) were facilely fabricated as a top-down process by a simple ultrasonication after the preparation of large nano-aggregates of PAH-AuNPs. Albumin played a critical role as a stabilizer and surfactant in making loosely associated large aggregates and thereby producing small gold nanoclusters (∼60 nm) of slightly negative charge upon ultrasonication. The prepared BSA/PAH-AuNCs displayed excellent hyperthermal effects (∼60 °C) in response to ∼808-nm NIR laser irradiation in a 4T1 cell system in vitro and in 4T1 cell tumor xenograft mice in vivo, indicating their remarkable potential to suppress breast cancer growth, without almost no significant toxicity in histology. Consequently, our gold nanoclusters should be considered as a promising photothermal agent that are easy to manufacture and exhibit marked anticancer effects in terms of tumor ablation.

Dendrimer-Stabilized Gold Nanoflowers Embedded with Ultrasmall Iron Oxide Nanoparticles for Multimode Imaging-Guided Combination Therapy of Tumors

Development of multifunctional theranostic nanoplatforms with improved diagnostic sensitivity and therapeutic efficiency of tumors still remains a great challenge. A unique multifunctional theranostic nanoplatform based on generation 5 (G5) poly(amidoamine) dendrimer-stabilized gold nanoflowers (NFs) embedded with ultrasmall iron oxide (USIO) nanoparticles (NPs) for multimode T 1-weighted magnetic resonance (MR)/computed tomography (CT)/photoacoustic (PA) imaging-guided combination photothermal therapy (PTT) and radiotherapy (RT) of tumors is reported here. G5 dendrimer-stabilized Au NPs and citric acid-stabilized USIO NPs are separately prepared, the two particles under a certain Fe/Au molar ratio are mixed to form complexes, the complexes are exposed to Au growth solution to form NFs via a seed-mediated manner, and the remaining dendrimer terminal amines are acetylated. The formed dendrimer-stabilized Fe3O4/Au NFs (for short, Fe3O4/Au DSNFs) have a mean diameter of 99.8 nm, display good colloidal stability and cytocompatibility, and exhibit a near-infrared absorption feature. The unique structure and composition of the Fe3O4/Au DSNFs endows them with a high r 1 relaxivity (3.22 mM-1 s-1) and photothermal conversion efficiency (82.7%), affording their uses as a theranostic nanoplatform for multimode MR/CT/PA imaging and combination PTT/RT of tumors with improved therapeutic efficacy, which is important for translational nanomedicine applications.

Gold-nanobranched-shell based drug vehicles with ultrahigh photothermal efficiency for chemo-photothermal therapy

Development of combined chemo-photothermal nanoplatform is of great interest for enhancing antitumor efficacy. Herein, a multifunctional drug delivery system was synthesized based on gold-nanobranched coated betulinic acid liposomes (GNBS-BA-Lips) for chemo-photothermal synergistic therapy. In this system, GNBS-BA-Lips exhibited broad near-infrared (NIR) absorption, preferable photothermal response and good photostability under NIR irradiation. Importantly, the gold-nanobranched nanostructure possessed high photothermal conversion efficiency (η = 55.7%), and the temperature change (ΔT) reached 43.2 °C after laser irradiation for 5 min. Upon NIR irradiation, the nanocarriers apparently endowed higher cell uptake, resulting in an enhanced intracellular drug accumulation. Furthermore, the tumor growth inhibition ratio achieved from chemo-photothermal therapy of GNBS-BA-Lips was 86.9 ± 1.1%, which was higher than that of the chemotherapy or photothermal therapy alone, showing an outstanding synergistic anticancer effect. Our data suggested that the nanoplatform should be considered as a critical platform in the development of cancer multi-mode therapies.