Photothermal nanodrugs: potential of TNF-gold nanospheres for cancer theranostics

Nanoparticle-based immunoengineering strategies for enhancing cancer immunotherapy

Cancer immunotherapy is a groundbreaking strategy that has revolutionized the field of oncology compared to other therapeutic strategies, such as surgery, chemotherapy, or radiotherapy. However, cancer complexity, tumor heterogeneity, and immune escape have become the main hurdles to the clinical application of immunotherapy. Moreover, conventional immunotherapies cause many harmful side effects owing to hyperreactivity in patients, long treatment durations and expensive cost. Nanotechnology is considered a transformative approach that enhances the potency of immunotherapy by capitalizing on the superior physicochemical properties of nanocarriers, creating highly targeted tissue delivery systems. These advantageous features include a substantial specific surface area, which enhances the interaction with the immune system. In addition, the capability to finely modify surface chemistry enables the achievement of controlled and sustained release properties. These advances have significantly increased the potential of immunotherapy, making it more powerful than ever before. In this review, we introduce recent nanocarriers for application in cancer immunotherapy based on strategies that target different main immune cells, including T cells, dendritic cells, natural killer cells, and tumor-associated macrophages. We also provide an overview of the role and significance of nanotechnology in cancer immunotherapy.

A Dual Concentration-Tailored Cytokine-Chemo Nanosystem to Alleviate Multidrug Resistance and Redirect Balance of Cancer Proliferation and Apoptosis

Background

Cancer multidrug resistance (MDR) is an important factor that severely affects the chemotherapeutic efficacy. Among various methods to bypass MDR, usage of cytokines, such as tumor necrosis factor alpha (TNFα) is attractive, which exerts antitumor effects of immunotherapeutic response and apoptotic/proinflammatory pathways. Nevertheless, the challenges remain how to implement targeted delivery of TNFα to reduce toxicity and manifest the involved signaling mechanism that subdues MDR.

Methods

We synthesized a multifunctional nanosytem, in which TNFα covalently bound to doxorubicin (Dox)-loaded pH-responsive mesoporous silica nanoparticles (MSN) through bi-functional polyethylene glycol (TNFα-PEG-MSN-Hydrazone-Dox) as a robust design to overcome MDR.

Results

The salient features of this nanoplatform are: 1) by judicious tailoring of TNFα concentration conjugated on MSN, we observed it could lead to a contrary effect of either proliferation or suppression of tumor growth; 2) the MSN-TNFα at higher concentration serves multiple functions, besides tumor targeting and inducer of apoptosis through extrinsic pathway, it inhibits the expression level of p-glycoprotein (P-gp), a cell membrane protein that functions as a drug efflux pump; 3) the enormous surface area of MSN provides for TNFα functionalization, and the nanochannels accommodate chemotherapeutics, Dox; 4) targeted intracellular release of Dox through the pH-dependent cleavage of hydrazone bonds induces apoptosis by the specific intrinsic pathway; and 5) TNFα-PEG-MSN-Hydrazone-Dox (MSN-Dox-TNFα) could infiltrate deep into the 3D spheroid tumor model through disintegration of tight junction proteins. When administered intratumorally in a Dox-resistant mouse tumor model, MSN-Dox-TNFα exhibited a synergistic therapeutic effect through the collective performances of TNFα and Dox.

Conclusion

We hereby develop and demonstrate a multifunctional MSN-Dox-TNFα system with concentration-tailored TNFα that can abrogate the drug resistance mechanism, and significantly inhibit the tumor growth through both intrinsic and extrinsic apoptosis pathways, thus making it a highly potential nanomedicine translated in the treatment of MDR tumors.

Role of Tunable Gold Nanostructures in Cancer Nanotheranostics: Implications on Synthesis, Toxicity, Clinical Applications and Their Associated Opportunities and Challenges

The existing diagnosis and treatment modalities have major limitations related to their precision and capability to understand several stages of disease development. A superior therapeutic system consists of a multifunctional approach in early diagnosis of the disease with a simultaneous progressive cure, using a precise medical approach towards complex treatment. These challenges can be addressed via nanotheranostics and explore suitable approaches to improve health care. Nanotechnology in combination with theranostics as an unconventional platform paved the way for developing novel strategies and modalities leading to diagnosis and therapy for complex disease conditions, ranging from acute to chronic levels. Among the metal nanoparticles, gold nanoparticles are being widely used for theranostics due to their inherent non-toxic nature and plasmonic properties. The unique optical and chemical properties of plasmonic metal nanoparticles along with theranostics have led to a promising era of plausible early detection of disease conditions, and they enable real-time monitoring with enhanced non-invasive or minimally invasive imaging of several ailments. This review aims to highlight the improvement and advancement brought to nanotheranostics by gold nanoparticles in the past decade. The clinical use of the metal nanoparticles in nanotheranostics is explained, along with the future perspectives on addressing the key applications related to diagnostics and therapeutics, respectively. The scope of gold nanoparticles and their realistic potential to design a sophisticated theranostic system is discussed in detail, along with their implications in clinical advancements which are the needs of the hour. The review concluded with the challenges, opportunities, and implications on translational potential of using gold nanoparticles in nanotheranostics.

Photothermal and Photodynamic Therapy of Tumors with Plasmonic Nanoparticles: Challenges and Prospects

Cancer remains one of the leading causes of death in the world. For a number of neoplasms, the efficiency of conventional chemo- and radiation therapies is insufficient because of drug resistance and marked toxicity. Plasmonic photothermal therapy (PPT) using local hyperthermia induced by gold nanoparticles (AuNPs) has recently been extensively explored in tumor treatment. However, despite attractive promises, the current PPT status is limited by laboratory experiments, academic papers, and only a few preclinical studies. Unfortunately, most nanoformulations still share a similar fate: great laboratory promises and fair preclinical trials. This review discusses the current challenges and prospects of plasmonic nanomedicine based on PPT and photodynamic therapy (PDT). We start with consideration of the fundamental principles underlying plasmonic properties of AuNPs to tune their plasmon resonance for the desired NIR-I, NIR-2, and SWIR optical windows. The basic principles for simulation of optical cross-sections and plasmonic heating under CW and pulsed irradiation are discussed. Then, we consider the state-of-the-art methods for wet chemical synthesis of the most popular PPPT AuNPs such as silica/gold nanoshells, Au nanostars, nanorods, and nanocages. The photothermal efficiencies of these nanoparticles are compared, and their applications to current nanomedicine are shortly discussed. In a separate section, we discuss the fabrication of gold and other nanoparticles by the pulsed laser ablation in liquid method. The second part of the review is devoted to our recent experimental results on laser-activated interaction of AuNPs with tumor and healthy tissues and current achievements of other research groups in this application area. The unresolved issues of PPT are the significant accumulation of AuNPs in the organs of the mononuclear phagocyte system, causing potential toxic effects of nanoparticles, and the possibility of tumor recurrence due to the presence of survived tumor cells. The prospective ways of solving these problems are discussed, including developing combined antitumor therapy based on combined PPT and PDT. In the conclusion section, we summarize the most urgent needs of current PPT-based nanomedicine.

Label-free photothermal disruption of cytotoxic aggregates rescues pathology in a C. elegans model of Huntington's disease

Aggregation of proteins is a prominent hallmark of virtually all neurodegenerative disorders including Alzheimer’s, Parkinson’s and Huntington’s diseases. Little progress has been made in their treatment to slow or prevent the formation of aggregates by post-translational modification and regulation of cellular responses to misfolded proteins. Here, we introduce a label-free, laser-based photothermal treatment of polyglutamine (polyQ) aggregates in a C. elegans nematode model of huntingtin-like polyQ aggregation. As a proof of principle, we demonstrated that nanosecond laser pulse-induced local photothermal heating can directly disrupt the aggregates so as to delay their accumulation, maintain motility, and extend the lifespan of treated nematodes. These beneficial effects were validated by confocal photothermal, fluorescence, and video imaging. The results obtained demonstrate that our theranostics platform, integrating photothermal therapy without drugs or other chemicals, combined with advanced imaging to monitor photothermal ablation of aggregates, initiates systemic recovery and thus validates the concept of aggregate-disruption treatments for neurodegenerative diseases in humans.

Bacterial navigation for tumor targeting and photothermally-triggered bacterial ghost transformation for spatiotemporal drug release

Cancer chemotherapy is confronted with challenges regarding the effective delivery of chemotherapeutics into tumor cells after systemic administration. Herein, we propose a strategy to load drugs into probiotic E. coli Nissle 1917 (EcN) for self-guided navigation to tumor tissues and subsequently release the drugs with in situ transformation into bacterial ghosts (BGs). Chemotherapeutic agent 5-fluorouracil (FU) and macrophage phenotype regulator zoledronic acid (ZOL) are loaded into EcN through electroporation, followed by decoration of Au nanorods on the ECN surface to construct EcN_Z/F@Au. High loading levels of 5FU (8.8%) and ZOL (10.5%) are achieved as well as high retention rates of bacterial viability (87%) and motion velocity (88%). Under near infrared (NIR) illumination the photothermal effect of Au nanorods elevates the local temperature to induce the transformation of live EcN into BGs. The created transmembrane channels initiate the gradual drug release from BGs, thus representing the first attempt to control the drug release via a biological evolution. An intermittent NIR illumination causes stepwise increases in the BG formation and drug release, which could implement an external on-off control and spatiotemporal drug release. Self-guided motion of EcN promotes efficient extravasation across blood vessels and preferential accumulation of drugs in tumors. In addition to the chemotherapeutic effect of FU, the local release of ZOL from EcN_Z/F@Au enhances valid polarization of tumor-associated macrophages toward the M1 phenotype and an effective production of proinflammatory cytokines, leading to a synergistic efficacy on tumor growth inhibition. Thus, this study demonstrates a feasible strategy to integrate chemotherapy, immunotherapy, and photothermal effects in a concise manner for effective cancer treatment with few side effects. STATEMENT OF SIGNIFICANCE: Bacteria are capable to trace and colonize in hypoxic tumor tissues. Bacterial drug carriers indicate limitations in efficient drug loading and effective release modulation. Herein, we propose a strategy to load drugs into bacteria for self-guided delivery and subsequently release the drugs in tumors with in situ transformation into bacterial ghost (BGs). Drugs are loaded into live bacteria through electroporation and Au nanorods are decorated on the bacterial surface, wherein the photothermal effect, chemotherapy, and immunotherapy are integrated in a concise manner. NIR illmumination of Au nanorods elevates the local temparature, induces the BG tranformation, and activates the spatiotemporal drug release, representing the first attempt of release modulation via a biological evolution.

Gold nanostructures as mediators of hyperthermia therapies in breast cancer

Breast cancer is the leading cause of cancer-related deaths among women. Due to the limitations of the current therapeutics, new treatment options are needed. Hyperthermia is a promising approach to improve breast cancer therapy, particularly when combined with chemo and radiotherapy. This area has gained more attention following association with nanotechnology, with the emergence of modalities, such as photothermal therapy (PTT). PTT is a simple, minimally invasive technique that requires a near infrared (NIR) light source and a PTT agent. Gold nanostructures are excellent PTT agents as they offer biocompatibility, versatility, high photothermal conversion efficiency, imaging contrast and an easily-modified surface. In this review, we describe the molecular basis and the current clinical aspects of hyperthermia-based therapies. The emergent area of nanoparticle-induced hyperthermia will be explored, in particular gold nanostructure-mediated PTT, focusing on recent preclinical studies for breast cancer management.

Clinical Application of Cytokines in Cancer Immunotherapy

Cytokines are key components of the immune system and play pivotal roles in anticancer immune response. Cytokines as either therapeutic agents or targets hold clinical promise for cancer precise treatment. Here, we provide an overview of the various roles of cytokines in the cancer immunity cycle, with a particular focus on the clinical researches of cytokine-based drugs in cancer therapy. We review 27 cytokines in 2630 cancer clinical trials registered with ClinicalTrials.gov that had completed recruitment up to January 2021 while summarizing important cases for each cytokine. We also discuss recent progress in methods for improving the delivery efficiency, stability, biocompatibility, and availability of cytokines in therapeutic applications.

Noninvasive and real-time monitoring of Au nanoparticle promoted cancer metastasis using in vivo flow cytometry

Cancer is the second leading cause of mortality globally, while cancer metastasis, which accounts for about 90% of cancer-related mortality, presents an extremely poor prognosis. Thus, various nanomedicines were designed and synthesized for cancer treatment, but nanomaterials could lead to endothelial leakiness and consequently facilitate intravasation and extravasation of cancer cells to form circulating tumor cells (CTCs), which were regarded as the potential metastatic seeds, possibly accelerating cancer metastasis. Neither possible metastatic sites were observed nor rare CTCs could be measured using common methods at the early stage of cancer metastasis, it is urgent to explore new technology to dynamically monitor nanomedicine promoted cancer metastasis with high sensitivity, which would be beneficial for cancer treatment as well as design and synthesis of nanomedicine. Herein, a novel optical biopsy tool i.e. in vivo flow cytometry (IVFC) was constructed to noninvasively and real-time monitor CTCs of tumor-bearing mice treated with various concentrations of Au nanoparticles. The in vivo experimental results demonstrated the promoted CTCs were Au nanoparticles dose-dependent consistent with the in vitro results, which showed Au nanoparticles induced dose-dependent gaps in the blood vessel endothelial walls to accelerate CTCs formation, making IVFC a promising biopsy tool in fundamental, pre-clinical and clinical investigation of nanomedicine and cancer metastasis.

Nano Metal based Herbal theranostics for Cancer management: coalescing nature's boon with nanotechnological advancement

Cancer is amongst the leading public health problems globally with continuously increasing prevalence rate that demands for extensive and expensive treatment. Despite availability of number of potential cancer therapies, inadequate success has been achieved due to complexity and heterogeneity of tumors. Moreover, late/ terminal stage cancer leads to multidrug resistance, excruciating side effects, recurrence, etc. This is because of low penetrability and deleterious effects of drug on non-target cells/ tissues. This requires for cost effective, efficacious, alternative/ adjunct, complementary medicines with targeted drug delivery approach. A potential strategy to resolve this difficulty is to use theranostics i.e., formulations having both a therapeutic element and an imaging agent. Phytotherapeutics have been extensively used since times immemorial, having wide acceptability, easy availability, minimal side effects and comparatively inexpensive. These herbal formulations are mostly orally administered and thus subjected to adverse pH, enzymatic degradation, poor gut absorption, low bioavailability and non-targeted delivery that ultimately lead to their poor effectiveness. Constraints associated with conventional phyto-pharmaceuticals can be improved by designing and using "Nano Delivery Systems" (NDS). The foremost aim of metal based NDS is to provide sustained drug release, site-specific action, improved patient's compliance and enhanced efficacy. Metal Nanocarriers carrying herbal drugs will avoid these obstructions, so the drug can circulate into the blood for a longer period of time and provide optimal amount of the drug to the site of action. Besides, Herbal drugs with NDS thus would be efficacious as alternative/ complementary cancer theranostics. Present review describes about novel theranostic systems employing metal nanocarriers with diagnostic and therapeutic properties as are an effective strategy for cancer treatment. These systems when conjugated with herbal drugs provide an efficient management strategy for cancer.

Strategies for the functionalisation of gold nanorods to reduce toxicity and aid clinical translation

Gold nanorods (GNRs) show great promise as photothermal therapy agents due to their remarkable ability to convert light into heat. In most cases, gold nanorods are synthesised via a seed-mediated method assisted by surfactants. However, the toxicity of these surfactants, principally cetrimonium ions, has prevented GNRs from being used more widely in vivo. To address this issue, various detoxification and functionalisation approaches have been proposed in recent years to replace or cover surfactant coatings on the gold surface. In this short review, the advantages and limitations of each approach are examined in the context of the recent progress made towards the design of GNRs suitable for use in the body.

The Use of a Combination of a Sugar and Surfactant to Stabilize Au Nanoparticle Dispersion against Aggregation during Freeze-Drying

Drying a suspension of nanoparticles typically results in the irreversible aggregation of nanoparticles; however, solutions that contain unstable ingredients are often converted into dried powders to prolong their shelf lives. In this study, the use of a combination of a surface-active agent and sugar was investigated with regard to avoiding the aggregation of nanoparticles during drying. Suspensions of Au nanoparticles (∼60 nm diameter, AuNPs) were freeze-dried in the presence of different combinations of various sugars with a surfactant. Sucrose monopalmitate (SEC16) was mainly used as the surfactant, based on a comparison of antiaggregation effects conferred by various surfactants. The freeze-dried AuNP suspension was then reconstituted, and the avoidance of AuNP aggregation was then examined. The results demonstrated that the use of a combination of a small amount of SEC16 and sugar resulted in a greater redispersibility of AuNPs after freeze-drying than when the individual components were used. Repetition tests of freeze-drying and reconstitution were conducted. The sucrose/SEC16 mixture was freeze-dried on an electroless-plated Au film and then analyzed by infrared spectroscopy. Strong interactions between SEC16 and the Au surface were detected, and these interactions appear to play a crucial role in the antiaggregation of AuNPs during freeze-drying.

Near IR responsive targeted integrated lipid polymer nanoconstruct for enhanced magnolol cytotoxicity in breast cancer

Advances in cancer nanotechnology aim at improving specificity and effectiveness for tumor treatment. Amalgamation of different treatment modalities is expected to provide better cancer combating. Herein, We developed a long circulating nanocarrier comprising trastuzumab (TZB) surface modified polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) co-encapsulating magnolol (Mag) and gold nanoparticles (GNPs). A modified single step nanoprecipitation method was adopted ensuring particle coating with D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) while co-encapsulating GNPs. TZB was then anchored on NPs surface using a carbodiimide chemistry. The cytotoxicity of the developed system was evaluated with and without photothermal irradiation. NPs cellular uptake was then followed using confocal microscopical imaging. A hybrid matrix composed of PLGA/TPGS and surface decorated with TZB with a conjugation efficiency of ˃65%, was confirmed via FTIR, ¹HNMR. GNPs could only be included in the NPs, when placed in the organic phase as evidenced by the shifted GNPs surface plasmonic resonance and confirmed via imaging coupled with energy dispersive X-ray analysis. Optimized NPs (136.1 ± 1.3 nm, −8.2 ± 1 mV and Mag encapsulation efficiency of 81.4 ± 1.8%) were able to boost Mag cytotoxicity on breast cancer cells while providing a selective multifunctional therapy with an added photothermal effect.

In vitro anti-tumor effect of high-fluence low-power laser light on apoptosis of human colorectal cancer cells

Colorectal cancer is the third most common malignancy all over the world, along with high morbidity and mortality. As a treatment, high-fluence low-power laser irradiation (HF-LPLI) has reported that its biostimulatory activity can suppress or even destruct tumor growth in neoplastic diseases. The aim of the present study is to examine a therapeutic capacity of HF-LPLI for colorectal cancer treatment by using human colon cancer cell (HT29) model. The in vitro cancer cell model was used to analyze the underlying mechanism of laser-induced apoptosis. Laser irradiation was performed five times (once a day for five consecutive days) with 635 nm laser light for 8 and 16 min (fluence = 128 and 256 J/cm²), respectively. The efficiency of the HF-LPLI treatment was evaluated by MTT, fluorescence staining, cell wound healing, and western blot test during the 5-day period. Experiment data showed that HF-LPLI had a dose-dependent stimulating effect on cell viability, migration, and apoptosis of HT29 cells. The inhibition effect of laser treatment at 256 J/cm² on cell viability was statistically significant. Meanwhile, the wound healing and western blot tests also confirmed that HF-LPLI could inhibit cell migration and induce cell apoptosis. The current research results demonstrate that 635 nm HF-LPLI can be an alternative treatment option for colorectal cancer by increasing the expression of caspase-3 and inducing HT29 tumor cell apoptosis through activation of the mitochondrial pathway.

Recent advances in combinatorial cancer therapy via multifunctionalized gold nanoparticles

The diverse behavior of nanogold in the therapeutic field is related to its unique size and shape. Nanogold offers improvements in modern diagnostic and therapeutic implications, increases disease specificity and targeted drug delivery, and is relatively economical compared with other chemotherapeutic protocols. The diagnosis of cancer and photothermal therapy improve drastically with the implementation of nanotechnology. Different types of nanoparticles, that is, gold silica nanoshells, nanorods and nanospheres of diverse shapes and geometries, are used widely in the photothermal therapy of cancerous cells and nodules. Numerous reviews have been published on the therapeutic applications of gold nanoparticles, but studies on combinatorial applications of nanogold in cancer therapy are limited. This review focuses on the combinatorial cancer therapy using optical properties of nanogold with different shapes and geometries, and their therapeutic applications in cancer diagnosis, photothermal therapy, cancer imaging and targeted drug delivery.

Tracking Gold Nanorods' Interaction with Large 3D Pancreatic-Stromal Tumor Spheroids by Multimodal Imaging: Fluorescence, Photoacoustic, and Photothermal Microscopies

Pancreatic cancer is one of the most complex types of cancers to detect, diagnose, and treat. However, the field of nanomedicine has strong potential to address such challenges. When evaluating the diffusion and penetration of theranostic nanoparticles, the extracellular matrix (ECM) is of crucial importance because it acts as a barrier to the tumor microenvironment. In the present study, the penetration of functionalized, fluorescent gold nanorods into large (>500 μm) multicellular 3D tissue spheroids was studied using a multimodal imaging approach. The spheroids were generated by co-culturing pancreatic cancer cells and pancreatic stellate cells in multiple ratios to mimic variable tumor-stromal compositions and to investigate nanoparticle penetration. Fluorescence live imaging, photothermal, and photoacoustic analysis were utilized to examine nanoparticle behavior in the spheroids. Uniquely, the nanorods are intrinsically photoacoustic and photothermal, enabling multi-imaging detection even when fluorescence tracking is not possible or ideal.

Vapor nanobubble is the more reliable photothermal mechanism for inducing endosomal escape of siRNA without disturbing cell homeostasis

Strategies for controlled delivery of therapeutic siRNA into living cells are in high demand as endosomal escape remains the most prominent bottleneck at the intracellular level. Photothermal properties of gold nanoparticles (AuNP) can be used to overcome the endosomal membrane barrier upon laser irradiation by two mechanisms: endosomal rupture by mechanical energy from water vapor nanobubbles (VNBs), or permeabilization of the endosomal membrane by heat diffusion. Here we evaluated how both mechanisms influence cargo release, transfection efficiency, acute cytotoxicity and cell homeostasis. Using a siRNA/AuNP drug delivery system we found that the in vitro release of siRNA from the AuNP carrier occurs equally efficiently by VNB formation or heat generation. Heat-mediated endosomal escape happened more efficiently in cells that had more particles per endosome, resulting in variable siRNA-induced downregulation (20-50%). VNB-mediated endosomal escape did not dependent on the number of AuNP per endosome, yielding high downregulations (50-60%) independent of the cell type. Effects on cell homeostasis by whole transcriptome analysis, showed a quick recover after 24 h or 48 h for either of both photothermal mechanisms. We conclude that VNBs are more consistent to induce efficient endosomal escape and gene silencing independent of the cell type without long lasting effects on cell homeostasis.

Gold nanomaterials as key suppliers in biological and chemical sensing, catalysis, and medicine

BACKGROUND

Gold nanoparticles (AuNPs) with unique physicochemical properties have received a great deal of interest in the field of biological, chemical and biomedical implementations. Despite the widespread use of AuNPs in chemical and biological sensing, catalysis, imaging and diagnosis, and more recently in therapy, no comprehensive summary has been provided to explain how AuNPs could aid in developing improved sensing and catalysts systems as well as medical settings.

SCOPE OF REVIEW

The chemistry of Au-based nanosystems was followed by reviewing different applications of Au nanomaterials in biological and chemical sensing, catalysis, imaging and diagnosis by a number of approaches, and finally synergistic combination therapy of different cancers. Afterwards, the clinical impacts of AuNPs, future application of AuNPs, and opportunities and challenges of AuNPs application were also discussed.

MAJOR CONCLUSIONS

AuNPs show exclusive colloidal stability and are considered as ideal candidates for colorimetric detection, catalysis, imaging, and photothermal transducers, because their physicochemical properties can be tuned by adjusting their structural dimensions achieved by the different manufacturing methods.

GENERAL SIGNIFICANCE

This review provides some details about using AuNPs in sensing and catalysis applications as well as promising theranostic nanoplatforms for cancer imaging and diagnosis, and sensitive, non-invasive, and synergistic methods for cancer treatment in an almost comprehensive manner.

Nanoformulations for glioblastoma multiforme: a new hope for treatment

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults, associated with a high mortality rate and a survival of between 12 and 15 months after diagnosis. Due to current treatment limitations involving surgery, radiotherapy and chemotherapy with temozolamide, there is a high rate of treatment failure and recurrence. To try to overcome these limitations nanotechnology has emerged as a novel alternative. Lipid, polymeric, silica and magnetic nanoparticles, among others, are being developed to improve GBM treatment and diagnosis. These nanoformulations have many advantages, including lower toxicity, biocompatibility and the ability to be directed toward the tumor. This article reviews the progress that have been made and the large variety of nanoparticles currently under study for GBM.

Pulsed-laser irradiation of multifunctional gold nanoshells to overcome trastuzumab resistance in HER2-overexpressing breast cancer

Background

HER2-overexpressing metastatic breast cancers are challenging practice in oncology when they become resistant to anti-HER2 therapies such as trastuzumab. In these clinical situations, HER2-overexpression persists in metastatic localizations, and can thus be used for active targeting using innovative therapeutic approaches. Functionalized gold nanoparticles with anti-HER2 antibody can be stimulated by near-infrared light to induce hyperthermia.

Methods

Here, hybrid anti-HER2 gold nanoshells were engineered for photothermal therapy to overcome trastuzumab resistance in HER2-overexpressing breast cancer xenografts.

Results

When gold nanoshells were administered in HER2-tumor xenografts, no toxicity was observed. A detailed pharmacokinetic study showed a time-dependent accumulation of gold nanoshells within the tumors, significantly greater with functionalized gold nanoshells at 72 h. This enabled us to optimize the treatment protocol and irradiate the mice when the anti-HER2 gold nanoshells had accumulated most in the tumors. After weekly injections of anti-HER2 gold nanoshells, and repeated irradiations with a femtosecond-pulsed laser over four weeks, tumor growth was significantly inhibited. Detailed tissue microscopic analyses showed that the tumor growth inhibition was due to an anti-angiogenic effect, coherent with a preferential distribution of the nanoshells in tumor microvessels. We also showed a direct tumor cell effect with apoptosis and inhibition of proliferation, coherent with an immune-mediated targeting of tumor cells by anti-HER2 nanoshells.

Conclusion

This preclinical study thus supports the use of anti-HER2 gold nanoshells and photothermal therapy to overcome trastuzumab resistance in HER2-overexpressing breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1305-x) contains supplementary material, which is available to authorized users.

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.

In vivo liquid biopsy using Cytophone platform for photoacoustic detection of circulating tumor cells in patients with melanoma

Most cancer deaths arise from metastases as a result of circulating tumor cells (CTCs) spreading from the primary tumor to vital organs. Despite progress in cancer prognosis, the role of CTCs in early disease diagnosis is unclear because of the low sensitivity of CTC assays. We demonstrate the high sensitivity of the Cytophone technology using an in vivo photoacoustic flow cytometry platform with a high pulse rate laser and focused ultrasound transducers for label-free detection of melanin-bearing CTCs in patients with melanoma. The transcutaneous delivery of laser pulses via intact skin to a blood vessel results in the generation of acoustic waves from CTCs, which are amplified by vapor nanobubbles around intrinsic melanin nanoclusters. The time-resolved detection of acoustic waves using fast signal processing algorithms makes photoacoustic data tolerant to skin pigmentation and motion. No CTC-associated signals within established thresholds were identified in 19 healthy volunteers, but 27 of 28 patients with melanoma displayed signals consistent with single, clustered, and likely rolling CTCs. The detection limit ranged down to 1 CTC/liter of blood, which is ~1000 times better than in preexisting assays. The Cytophone could detect individual CTCs at a concentration of ≥1 CTC/ml in 20 s and could also identify clots and CTC-clot emboli. The in vivo results were verified with six ex vivo methods. These data suggest the potential of in vivo blood testing with the Cytophone for early melanoma screening, assessment of disease recurrence, and monitoring of the physical destruction of CTCs through real-time CTC counting.

Gold nanoparticle surface engineering strategies and their applications in biomedicine and diagnostics

Gold nanoparticles (AuNPs) have found a wide range of biomedical and environmental monitoring applications (viz. drug delivery, diagnostics, biosensing, bio-imaging, theranostics, and hazardous chemical sensing) due to their excellent optoelectronic and enhanced physico-chemical properties. The modulation of these properties is done by functionalizing them with the synthesized AuNPs with polymers, surfactants, ligands, drugs, proteins, peptides, or oligonucleotides for attaining the target specificity, selectivity and sensitivity for their various applications in diagnostics, prognostics, and therapeutics. This review intends to highlight the contribution of such AuNPs in state-of-the-art ventures of diverse biomedical applications. Therefore, a brief discussion on the synthesis of AuNPs has been summarized prior to comprehensive detailing of their surface modification strategies and the applications. Here in, we have discussed various ways of AuNPs functionalization including thiol, phosphene, amine, polymer and silica mediated passivation strategies. Thereafter, the implications of these passivated AuNPs in sensing, surface-enhanced Raman spectroscopy (SERS), bioimaging, drug delivery, and theranostics have been extensively discussed with the a number of illustrations.

Gold nanoparticle surface engineering strategies and their applications in biomedicine and diagnostics

Gold nanoparticles (AuNPs) have found a wide range of biomedical and environmental monitoring applications (viz. drug delivery, diagnostics, biosensing, bio-imaging, theranostics, and hazardous chemical sensing) due to their excellent optoelectronic and enhanced physico-chemical properties. The modulation of these properties is done by functionalizing them with the synthesized AuNPs with polymers, surfactants, ligands, drugs, proteins, peptides, or oligonucleotides for attaining the target specificity, selectivity and sensitivity for their various applications in diagnostics, prognostics, and therapeutics. This review intends to highlight the contribution of such AuNPs in state-of-the-art ventures of diverse biomedical applications. Therefore, a brief discussion on the synthesis of AuNPs has been summarized prior to comprehensive detailing of their surface modification strategies and the applications. Here in, we have discussed various ways of AuNPs functionalization including thiol, phosphene, amine, polymer and silica mediated passivation strategies. Thereafter, the implications of these passivated AuNPs in sensing, surface-enhanced Raman spectroscopy (SERS), bioimaging, drug delivery, and theranostics have been extensively discussed with the a number of illustrations.

Docetaxel-Loaded Hyaluronic Acid-Cathepsin B-Cleavable-Peptide-Gold Nanoparticles for the Treatment of Cancer

Gold nanoparticles are commonly used for medical applications such as drug delivery and as therapeutic and diagnostic materials because of their unique properties. In this study, we prepared docetaxel (DTX)-loaded hyaluronic acid-cleavable-peptide-gold nanoparticles for the treatment of cancer by selectively delivering DTX into the tumor and, thus, enhancing the therapeutic effect of DTX; further, we determined synergistic effects of the nanoparticles using laser treatment. The DTX-loaded hyaluronic acid-cleavable-peptide-gold nanoparticles prepared in this study had an average size of 75 nm and negative surface charge. The nanoparticles revealed greater cytotoxicity and higher tumor suppression efficacy in tumor models than free DTX under near-infrared laser irradiation. Therefore, the nanoparticle formulation prepared in this study could be utilized for targeted drug delivery and in combination with other cancer therapies.

Gold nanoparticle-induced sonosensitization enhances the antitumor activity of ultrasound in colon tumor-bearing mice

PURPOSE

As a noninvasive and nonionizing radiation, ultrasound can be focused remotely, transferring acoustic energy deep in the body, thereby addressing the penetration depth barrier of the light-based therapies. In cancer therapy, the effectiveness of ultrasound can be enhanced by utilizing nanomaterials that exhibit sonosensitizing properties called as nanosonosensitizers. The gold nanoparticle (AuNP) has been recently presented as a potent nanosonosensitizer with the potential to simultaneously enhance both the thermal and mechanical interactions of ultrasound with the tissue of the human body. Accordingly, this paper attempts to evaluate the in vivo antitumor efficiency of ultrasound in combination with AuNP.

METHODS

BALB/c mice-bearing CT26 colorectal tumor model was intraperitoneally injected with AuNPs and then subjected to ultrasound irradiation (1 MHz; 2 W/cm2 ; 10 min) for three sessions. Furthermore, [18 F]FDG (2-deoxy-2-[18 F]fluoro-d-glucose) positron-emission tomography (PET) imaging was performed and the radiomic features from different feature categorizes were extracted to quantify the tumors' phenotype.

RESULTS

The tumors were dramatically shrunk and the mice appeared healthy over 21 days of study span without the evidence of relapse. The animals treated with AuNP + ultrasound exhibited an obvious decline in tumor metabolic parameters such as standard uptake value (SUV), total lesion glycolysis (TLG), and metabolic tumor volume (MTV) compared to other treatment groups.

CONCLUSION

These findings support the use of AuNP as a potent sonosensitizing agent with the potential to use the thermal and mechanical effects of ultrasound so as to cause damage to the focused tumor site, resulting in an improved antitumor efficacy.

Nanotechnology for Cancer Therapy Based on Chemotherapy

Chemotherapy has been widely applied in clinics. However, the therapeutic potential of chemotherapy against cancer is seriously dissatisfactory due to the nonspecific drug distribution, multidrug resistance (MDR) and the heterogeneity of cancer. Therefore, combinational therapy based on chemotherapy mediated by nanotechnology, has been the trend in clinical research at present, which can result in a remarkably increased therapeutic efficiency with few side effects to normal tissues. Moreover, to achieve the accurate pre-diagnosis and real-time monitoring for tumor, the research of nano-theranostics, which integrates diagnosis with treatment process, is a promising field in cancer treatment. In this review, the recent studies on combinational therapy based on chemotherapy will be systematically discussed. Furthermore, as a current trend in cancer treatment, advance in theranostic nanoparticles based on chemotherapy will be exemplified briefly. Finally, the present challenges and improvement tips will be presented in combination therapy and nano-theranostics.

A priming dose protects against gold nanoparticles-induced proinflammatory cytokines mRNA expression in mice

AIM

To study the effect of priming doses of gold nanoparticles (GNPs) on proinflammatory cytokines in different organs of mice.

MATERIALS & METHODS

Mice were injected with a single or two doses (priming group) of GNPs (5, 20 and 50 nm) and sacrificed after 1 or 7 days. The mRNA expressions of IL-1β, IL-6 and TNF-α were determined in liver, kidney and spleen.

RESULTS

A single injection of 5 nm GNPs significantly increased the mRNA expressions of IL-1β and IL-6 in liver, which were normalized on day 7. In spleen, the GNPs of all sizes significantly increased IL-1β and IL-6 mRNA expressions on day 1 that persisted on day 7. The priming dose of GNPs protected the animals against the acute phase induction of IL-1β and IL-6 expressions in liver and spleen.

CONCLUSION

Primed animals showed protection against GNP-induced acute immune activation suggesting the importance of the priming dose in nanomedicine.

Inflammation and Cancer: In Medio Stat Nano

Cancer treatment still remains a challenge due to the several limitations of currently used chemotherapeutics, such as their poor pharmacokinetics, unfavorable chemical properties, as well as inability to discriminate between healthy and diseased tissue. Nanotechnology offered potent tools to overcome these limitations. Drug encapsulation within a delivery system permitted i) to protect the payload from enzymatic degradation/ inactivation in the blood stream, ii) to improve the physicochemical properties of poorly water-soluble drugs, like paclitaxel, and iii) to selectively deliver chemotherapeutics to the cancer lesions, thus reducing the off-target toxicity, and promoting the intracellular internalization. To accomplish this purpose, several strategies have been developed, based on biological and physical changes happening locally and systemically as a consequence of tumorigenesis. Here, we will discuss the role of inflammation in the different steps of tumor development and the strategies based on the use of nanoparticles that exploit the inflammatory pathways in order to selectively target the tumor-associated microenvironment for therapeutic and diagnostic purposes.

Recent Advances in Cancer Therapy Based on Dual Mode Gold Nanoparticles

Many tumor-targeted strategies have been used worldwide to limit the side effects and improve the effectiveness of therapies, such as chemotherapy, radiotherapy (RT), etc. Biophotonic therapy modalities comprise very promising alternative techniques for cancer treatment with minimal invasiveness and side-effects. These modalities use light e.g., laser irradiation in an extracorporeal or intravenous mode to activate photosensitizer agents with selectivity in the target tissue. Photothermal therapy (PTT) is a minimally invasive technique for cancer treatment which uses laser-activated photoabsorbers to convert photon energy into heat sufficient to induce cells destruction via apoptosis, necroptosis and/or necrosis. During the last decade, PTT has attracted an increased interest since the therapy can be combined with customized functionalized nanoparticles (NPs). Recent advances in nanotechnology have given rise to generation of various types of NPs, like gold NPs (AuNPs), designed to act both as radiosensitizers and photothermal sensitizing agents due to their unique optical and electrical properties i.e., functioning in dual mode. Functionalized AuNPS can be employed in combination with non-ionizing and ionizing radiation to significantly improve the efficacy of cancer treatment while at the same time sparing normal tissues. Here, we first provide an overview of the use of NPs for cancer therapy. Then we review many recent advances on the use of gold NPs in PTT, RT and PTT/RT based on different types of AuNPs, irradiation conditions and protocols. We refer to the interaction mechanisms of AuNPs with cancer cells via the effects of non-ionizing and ionizing radiations and we provide recent existing experimental data as a baseline for the design of optimized protocols in PTT, RT and PTT/RT combined treatment.

Doxorubicin-fucoidan-gold nanoparticles composite for dual-chemo-photothermal treatment on eye tumors

The current research demonstrates the feasible biomedical application of AuNPs coated with doxorubicin (Dox)-loaded fucoidan (Fu) for dual-chemotherapy and photothermal treatment (PTT) on eye tumors in vitro and in vivo. Marine-derived Fu was used as a capping agent to achieve high photostability for AuNPs, and Dox as a FDA-approved anti-cancer drug was added to induce chemotherapy. The synthesized Dox-Fu@AuNPs exhibited high cytotoxicity on the tumor cells and strong light absorption for temperature increase in vitro. After intratumoral injection of Dox-Fu@AuNPs in the rabbit eye tumors, PTT-assisted Dox-Fu@AuNPs entailed the complete removal of the eye tumors without recurrence for 14 days after the treatment. Photoacoustic image contrast from the tumor regions was enhanced due to selective light absorption by the administered Dox-Fu@AuNPs. Therefore, the proposed Dox-Fu@AuNPs can be a potential nano-theranostic material for treating and diagnosing the eye tumors.

Evaluation of anti‐bacterial activity of silver nanoparticles synthesised by coprophilous fungus PM0651419

The study explored biological synthesis of metallic silver nanoparticles (AgNPs) from the less explored non‐pathogenic coprophilous fungus, sterile mycelium, PM0651419 and evaluates the antimicrobial efficacy of biosynthesised AgNPs when impregnated in wound fabrics and in combination with six antimicrobial agents. AgNPs alone proved to be potent antibacterial agents and in combination they enhanced the antibacterial activity and spectrum of antibacterials used in the study against a microbiologically diverse battery of Gram positive, Gram negative and multidrug‐resistant bacteria. AgNPs impregnated on the wound dressings established their antibacterial activity by significantly reducing the bacterial load of pathogenic bacteria like Staphylococcus aureus and Bacillus subtilis e stablishing potential as effective antimicrobial wound dressings for treatment of polymicrobial wound infections. This study presents the first report on the potential of biosynthesis of AgNPs from the under explored class of coprophilous fungi. Their promise to be used in wound dressings and as potent antibacterials alone and in combination is evaluated

Triple-negative breast cancer targeting and killing by EpCAM-directed, plasmonically active nanodrug systems

An ongoing need for new cancer therapeutics exists, especially ones that specifically home and target triple-negative breast cancer. Because triple-negative breast cancer express low or are devoid of estrogen, progesterone, or Her2/Neu receptors, another target must be used for advanced drug delivery strategies. Here, we engineered a nanodrug delivery system consisting of silver-coated gold nanorods (AuNR/Ag) targeting epithelial cell adhesion/activating molecule (EpCAM) and loaded with doxorubicin. This nanodrug system, AuNR/Ag/Dox-EpCAM, was found to specifically target EpCAM-expressing tumors compared to low EpCAM-expressing tumors. Namely, the nanodrug had an effective dose (ED₅₀) of 3 μM in inhibiting 4T1 cell viability and an ED₅₀ of 110 μM for MDA-MD-231 cells. Flow cytometry data indicated that 4T1 cells, on average, express two orders of magnitude more EpCAM than MDA-MD-231 cells, which correlates with our ED₅₀ findings. Moreover, due to the silver coating, the AuNR/Ag can be detected simultaneously by surface-enhanced Raman spectroscopy and photoacoustic microscopy. Analysis by these imaging detection techniques as well as by inductively coupled plasma mass spectrometry showed that the targeted nanodrug system was taken up by EpCAM-expressing cells and tumors at significantly higher rates than untargeted nanoparticles (p < 0.05). Thus, this approach establishes a plasmonically active nanodrug theranostic for triple-negative breast cancer and, potentially, a delivery platform with improved multimodal imaging capability for other clinically relevant chemotherapeutics with dose-limiting toxicities, such as platinum-based or taxane-based therapies.

Silver-coated gold nanorods deliver drugs to a difficult-to-treat breast cancer by targeting an over-expressed antigen on its surface. Ruud Dings and colleagues at the University of Arkansas in the USA loaded the chemotherapeutic drug doxorubicin onto silver-coated gold nanorods that were conjugated with an antibody that specifically targets an over-expressed antigen on many types of ‘triple-negative breast cancers’ (TNBCs). Unlike other breast cancers, TNBCs lack certain receptors, making them difficult to target with cancer therapies. The team found that one of the two TNBC cell lines studied over-expressed the epithelial antigen EpCAM 100 times more than the other. Their drug-loaded silver-coated gold nanorods specifically targeted the EpCAM over-expressing cells over the low-expressing ones. The nanorods’ coatings also allowed them to be easily detected by two different imaging techniques: surfaced-enhanced Raman spectroscopy and photoacoustic microscopy.

In vivo noninvasive analysis of graphene nanomaterial pharmacokinetics using photoacoustic flow cytometry

Graphene-based nanomaterials (GBNs) are quickly revolutionizing modern electronics, energy generation and storage, clothing and biomedical devices. Due to GBN's variety of physical and chemical parameters that define their toxicity and their aggregation in suspension, interpreting its toxicology without accurate information on graphene's distribution and behavior in live organisms is challenging. In this work, we present a laser-based optical detection methodology for noninvasive detection and pharmacokinetics analysis of GBNs directly in blood flow in mice using in vivo photoacoustic (PA) flow cytometry (PAFC). PAFC provides unique insight on how chemical modifications of GBNs affect their distribution in blood circulation and how quickly they are eliminated from the flow. Overall, PAFC provided unique data crucial for understanding GBN toxicity through real-time detection of GBNs using their intrinsic light absorption contrast. Copyright © 2017 John Wiley & Sons, Ltd.

Galectin-1-based tumour-targeting for gold nanostructure-mediated photothermal therapy

PURPOSE

To demonstrate delivery of Au nanocages to cells using the galectin-1 binding peptide anginex (Ax) and to demonstrate the value of this targeting for selective in vitro photothermal cell killing.

MATERIALS AND METHODS

Au nanocages were synthesised, coated with polydopamine (PDA), and conjugated with Ax. Tumour and endothelial cell viability was measured with and without laser irradiation. Photoacoustic (PA) mapping and PA flow cytometry were used to confirm cell targeting in vitro and in tissue slices ex vivo.

RESULTS

Cell viability was maintained at ≥50% at 100 pM suggesting low toxicity of the nanocage alone. Combining the targeted construct (25 pM) with low power 808 nm laser irradiation for 10-20 min (a duration previously shown to induce rapid and sustained heating of Au nanocages [AuNC] in solution), resulted in over 50% killing of endothelial and tumour cells. In contrast, the untargeted construct combined with laser irradiation resulted in negligible cell killing. We estimate approximately 6 × 10⁴ peptides were conjugated to each nanocage, which also resulted in inhibition of cell migration. Binding of the targeted nanocage reached a plateau after three hours, and cell association was 20-fold higher than non-targeted nanocages both in vitro and ex vivo on tumour tissue slices. A threefold increase in tumour accumulation was observed in preliminary in vivo studies.

CONCLUSIONS

These studies demonstrate Ax's potential as an effective targeting agent for Au-based theranostics to tumour and endothelial cells, enabling photothermal killing. This platform further suggests potential for multimodal in vivo therapy via next-generation drug-loaded nanocages.

Gold nanoparticles, radiations and the immune system: Current insights into the physical mechanisms and the biological interactions of this new alliance towards cancer therapy

Considering both cancer's serious impact on public health and the side effects of cancer treatments, strategies towards targeted cancer therapy have lately gained considerable interest. Employment of gold nanoparticles (GNPs), in combination with ionizing and non-ionizing radiations, has been shown to improve the effect of radiation treatment significantly. GNPs, as high-Z particles, possess the ability to absorb ionizing radiation and enhance the deposited dose within the targeted tumors. Furthermore, they can convert non-ionizing radiation into heat, due to plasmon resonance, leading to hyperthermic damage to cancer cells. These observations, also supported by experimental evidence both in vitro and in vivo systems, reveal the capacity of GNPs to act as radiosensitizers for different types of radiation. In addition, they can be chemically modified to selectively target tumors, which renders them suitable for future cancer treatment therapies. Herein, a current review of the latest data on the physical properties of GNPs and their effects on GNP circulation time, biodistribution and clearance, as well as their interactions with plasma proteins and the immune system, is presented. Emphasis is also given with an in depth discussion on the underlying physical and biological mechanisms of radiosensitization. Furthermore, simulation data are provided on the use of GNPs in photothermal therapy upon non-ionizing laser irradiation treatment. Finally, the results obtained from the application of GNPs at clinical trials and pre-clinical experiments in vivo are reported.

Remotely Triggered Nano-Theranostics For Cancer Applications

Nanotechnology has enabled the development of smart theranostic platforms that can concurrently diagnose disease, start primary treatment, monitor response, and, if required, initiate secondary treatments. Recent in vivo experiments demonstrate the promise of using theranostics in the clinic. In this paper, we review the use of remotely triggered theranostic nanoparticles for cancer applications, focusing heavily on advances in the past five years. Remote triggering mechanisms covered include photodynamic, photothermal, phototriggered chemotherapeutic release, ultrasound, electro-thermal, magneto-thermal, X-ray, and radiofrequency therapies. Each section includes a brief overview of the triggering mechanism and summarizes the variety of nanoparticles employed in each method. Emphasis in each category is placed on nano-theranostics with in vivo success. Some of the nanotheranostic platforms highlighted include photoactivatable multi-inhibitor nanoliposomes, plasmonic nanobubbles, reduced graphene oxide-iron oxide nanoparticles, photoswitching nanoparticles, multispectral optoacoustic tomography using indocyanine green, low temperature sensitive liposomes, and receptor-targeted iron oxide nanoparticles loaded with gemcitabine. The studies reviewed here provide strong evidence that the field of nanotheranostics is rapidly evolving. Such nanoplatforms may soon enable unique advances in the clinical management of cancer. However, reproducibility in the synthesis procedures of such "smart" platforms that lend themselves to easy scale-up in their manufacturing, as well as the development of new and improved models of cancer that are more predictive of human responses, need to happen soon for this field to make a rapid clinical impact.

Selection and Identification of Molecular Gold Clusters at the Nano(gram) Scale: Reversed Phase HPLC-ESI-MS of a Mixture of Au-Peth MPCs

Recent advances in cluster synthesis make it possible to produce an enormous variety molecule-like MPCs of size, composition, shape, and surface-chemical combinations. In contrast to the significant growth in the synthetic capability to generate these materials, progress in establishing the physicochemical basis for their observed properties has remained limited. The main reason for this has been the lack of the analytical capability to generate and measure samples of suitably high (molecular) purity; such capability is also essential to support therapeutic and diagnostic MPC development. In order for MPC products to get to market, especially those products that are medical-field related, characterization is required to identify and quantify all components present in a material mixture. Here, we show results from analysis of several synthetic mixtures of gold MPCs by nonaqueous reversed-phase chromatography coupled with mass spectrometry detection. The additional or hidden components, revealed to be present in these mixtures, provide novel insights into their comparative stability and interactions.

Regulating Cell Apoptosis on Layer-by-Layer Assembled Multilayers of Photosensitizer-Coupled Polypeptides and Gold Nanoparticles

The design of advanced, nanostructured materials by layer-by-layer (LbL) assembly at the molecular level is of great interest because of the broad application of these materials in the biomedical field especially in regulating cell growth, adhesion, movement, differentiation and detachment. Here, we fabricated functional hybrid multilayer films by LbL assembly of biocompatible photosensitizer-coupled polypeptides and collagen-capped gold nanoparticles. The resulting multilayer film can well accommodate cells for adhesion, growth and proliferation. Most significantly, controlled cell apoptosis (detachment) and patterning of the multilayer film is achieved by a photochemical process yielding reactive oxygen species (ROS). Moreover, the site and shape of apoptotic cells can be controlled easily by adjusting the location and shape of the laser beam. The LbL assembled multilayer film with integration of functions provides an efficient platform for regulating cell growth and apoptosis (detachment).