Highly Efficient Photothermal Therapy with Cell-Penetrating Peptide-Modified Bumpy Au Triangular Nanoprisms using Low Laser Power and Low Probe Dose

Au-Fe3O4 Janus nanoparticles for imaging-guided near infrared-enhanced ferroptosis therapy in triple negative breast cancer

Triple-negative breast cancer (TNBC) is insensitive to conventional therapy due to its highly invasive nature resulting in poor therapeutic outcomes. Recent studies have shown multiple genes associated with ferroptosis in TNBC, suggesting an opportunity for ferroptosis-based treatment of TNBC. However, the efficiency of present ferroptosis agents for cancer is greatly restricted due to lack of specificity and low intracellular levels of H2O2 in cancer cells. Herein, we report a nano-theranostic platform consisting of gold (Au)-iron oxide (Fe3O4) Janus nanoparticles (GION@RGD) that effectively enhances the tumor-specific Fenton reaction through utilization of near-infrared (NIR) lasers, resulting in the generation of substantial quantities of toxic hydroxyl radicals (•OH). Specifically, Au nanoparticles (NPs) converted NIR light energy into thermal energy, inducing generation of abundant intracellular H2O2, thereby enhancing the iron-induced Fenton reaction. The generated •OH not only lead to apoptosis of malignant tumor cells but also induce the accumulation of lipid peroxides, causing ferroptosis of tumor cells. After functionalizing with the activity-targeting ligand RGD (Arg-Gly-Asp), precise synergistic treatment of TNBC was achieved in vivo under the guidance of Fe3O4 enhanced T2-weighted magnetic resonance imaging (MRI). This synergistic treatment strategy of NIR-enhanced ferroptosis holds promise for the treatment of TNBC.

Broadband and Spectrally Selective Photothermal Conversion through Nanocluster Assembly of Disordered Plasmonic Metasurfaces

Plasmonic metasurfaces have been realized for efficient light absorption, thereby leading to photothermal conversion through nonradiative decay of plasmonic modes. However, current plasmonic metasurfaces suffer from inaccessible spectral ranges, costly and time-consuming nanolithographic top-down techniques for fabrication, and difficulty of scale-up. Here, we demonstrate a new type of disordered metasurface created by densely packing plasmonic nanoclusters of ultrasmall size on a planar optical cavity. The system either operates as a broadband absorber or offers a reconfigurable absorption band right across the visible region, resulting in continuous wavelength-tunable photothermal conversion. We further present a method to measure the temperature of plasmonic metasurfaces via surface-enhanced Raman spectroscopy (SERS), by incorporating single-walled carbon nanotubes (SWCNTs) as an SERS probe within the metasurfaces. Our disordered plasmonic system, generated by a bottom-up process, offers excellent performance and compatibility with efficient photothermal conversion. Moreover, it also provides a novel platform for various hot-electron and energy-harvesting functionalities.

Synergistic effects of integrin binding peptide (RGD) and photobiomodulation therapies on bone-like microtissues to enhance osteogenic differentiation

Bone tissue engineering aims to diversify and enhance the strategies for bone regeneration to overcome bone-related health problems. Bone mimetic peptides such as Gly-Arg-Gly-Asp-Ser (RGD) are useful tools for osteogenic differentiation. Similarly, photobiomodulation (PBM) at 600-800 nm of wavelength range improves bone tissue healing via the production of intracellular reactive oxygen species (ROS), ATP synthesis, and nitric oxide (NO) release. Besides, traditional monolayer cell culture models have limited conditions to exhibit the details of a mechanism such as a peptide or PBM therapy. However, scaffold-free microtissues (SFMs) can mimic a tissue more properly and be an efficient way to understand the mechanism of therapy via cell-cell interaction. Thus, the synergistic effects of RGD peptide (1 mM) and PBM applications (1 J/cm² energy density at 655 nm of wavelength and 5 J/cm² energy density at 808 nm of wavelength) were evaluated on SFMs formed with the co-culture of Human Bone Marrow Stem Cells (hBMSC) and Human Umbilical Vein Endothelial Cells (HUVEC) for osteogenic differentiation. Cell viability assays, mechanistic analysis, and the evaluation of osteogenic differentiation markers were performed. Combined therapies of RGD and PBM were more successful to induce osteogenic differentiation than single therapies. Especially, RGD + PBM at 655 nm group exhibited a higher capability of osteogenic differentiation via ROS production, ATP synthesis, and NO release. It can be concluded that the concomitant use of RGD and PBM may enhance bone regeneration and become a promising therapeutic tool to heal bone-related problems in clinics.

Photothermal Nanomaterials: A Powerful Light-to-Heat Converter

All forms of energy follow the law of conservation of energy, by which they can be neither created nor destroyed. Light-to-heat conversion as a traditional yet constantly evolving means of converting light into thermal energy has been of enduring appeal to researchers and the public. With the continuous development of advanced nanotechnologies, a variety of photothermal nanomaterials have been endowed with excellent light harvesting and photothermal conversion capabilities for exploring fascinating and prospective applications. Herein we review the latest progresses on photothermal nanomaterials, with a focus on their underlying mechanisms as powerful light-to-heat converters. We present an extensive catalogue of nanostructured photothermal materials, including metallic/semiconductor structures, carbon materials, organic polymers, and two-dimensional materials. The proper material selection and rational structural design for improving the photothermal performance are then discussed. We also provide a representative overview of the latest techniques for probing photothermally generated heat at the nanoscale. We finally review the recent significant developments of photothermal applications and give a brief outlook on the current challenges and future directions of photothermal nanomaterials.

Tumor-targeting semiconducting polymer nanoparticles: efficient adjuvant photothermal therapy using ultra-low laser power inhibits recurrences after breast-conserving surgery

The need for adjuvant therapy to inhibit local recurrence after breast-conserving surgery with minimal side effects is great. Adjuvant photothermal therapy (aPTT) has the potential to replace radiotherapy and eliminates its inherent damage to healthy tissues. Herein, we functionalized semiconducting polymer nanoparticles (SPNs) with cRGD-peptide and silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) (NIR775) to target breast cancer and perform aPTT under an ultra-low laser power (0.2 W cm^-2) after breast-conserving surgery (BCS). The synthesized RGD-SPN_NIR775 showed an excellent photothermal conversion efficiency and biocompatibility and was demonstrated to accumulate in tumors specifically. The BCS could be performed with confidence under the guidance of preoperative and postoperative fluorescence imaging. Notably, the aPTT completely inhibited the local recurrence after the BCS without compromising the cosmetic effect of the BCS. These results indicate the prospect of RGD-SPN_NIR775 as a theranostic nanoplatform for efficient aPTT using an ultra-low laser power to control recurrence after BCS.

A Multilayered Mesoporous Gold Nanoarchitecture for Ultraeffective Near-Infrared Light-Controlled Chemo/Photothermal Therapy for Cancer Guided by SERS Imaging

Surface-enhanced Raman scattering (SERS) imaging has emerged as a promising tool for guided cancer diagnosis and synergistic therapies, such as combined chemotherapy and photothermal therapy (chemo-PTT). Yet, existing therapeutic agents often suffer from low SERS sensitivity, insufficient photothermal conversion, or/and limited drug loading capacity. Herein, a multifunctional theragnostic nanoplatform consisting of mesoporous silica-coated gold nanostar with a cyclic Arg-Gly-Asp (RGD)-coated gold nanocluster shell (named RGD-pAS@AuNC) is reported that exhibits multiple "hot spots" for pronouncedly enhanced SERS signals and improved near-infrared (NIR)-induced photothermal conversion efficiency (85.5%), with a large capacity for high doxorubicin (DOX) loading efficiency (34.1%, named RGD/DOX-pAS@AuNC) and effective NIR-triggered DOX release. This nanoplatform shows excellent performance in xenograft tumor model of HeLa cell targeting, negligible cytotoxicity, and good stability both in vitro and in vivo. By SERS imaging, the optimal temporal distribution of injected RGD/DOX-pAS@AuNCs at the tumor site is identified for NIR-triggered local chemo-PTT toward the tumor, achieving ultraeffective therapy in tumor cells and tumor-bearing mouse model with 5 min of NIR irradiation (0.5 W cm^-2 ). This work offers a promising approach to employing SERS imaging for effective noninvasive tumor treatment by on-site triggered chemo-PTT.

The complex of miRNA2861 and cell-penetrating, dimeric α-helical peptide accelerates the osteogenesis of mesenchymal stem cells

BACKGROUND

The restoration of the functional ability of mesenchymal stem cells (MSCs) using epigenetic modification is very promising for patients with weak osteogenesis ability. This study focused on the acceleration of osteogenesis from MSCs using microRNA (miRNA)2861 and a cell-penetrating peptide (CPP), LK.

METHODS

We performed MSCs penetration test of complex between the LK peptides and miRNA 2861. Three different experiments were performed to investigate the effects of miRNA 2861 on osteogenic differentiation in MSCs: 1) intensity of alizarin red staining, which reflects the status of mineralization by osteoblasts; 2) gene expression related to osteoblast differentiation; and 3) confirmation of corresponding protein translation for comparison with RNA expression levels.

RESULTS

We found that cLK effectively delivered miRNA 2861 into the cytoplasm of human MSCs and accelerated osteogenic differentiation from MSCs, as well as mineralization.

CONCLUSION

The complex of miRNA 2861 with LK may have a positive effect on the osteogenic differentiation from MSCs and mineralization. Therapies using miRNAs combined with LK may be good candidates for the augmentation of osteogenesis in patients.

Multifunctional Bi NSs@BSA Nanoplatform Guided by CT Imaging for Effective Photothermal Therapy

Photothermal therapy (PTT) has attracted great attention as an anticancer treatment strategy. With the rapid development of nanomedicine, multifunctional inorganic nanophotothermal agents provide a new way to improve the effect of PTT. Herein, bovine serum albumin (BSA)-modified Bi nanosheets (Bi NSs) with good biocompatibility were synthesized by a facile redox and ball milling method and applied as a photothermal agent for the enhancement of PTT. Owing to the strong near-infrared absorption, Bi NSs exhibit high photothermal conversion efficiency (η = 36.17%) under 808 nm laser irradiation and can serve as a nanotherapeutic agent for cancer therapy. In addition, in vitro cell safety analysis also suggests that the toxicity of BSA-modified Bi NSs is negligible. Upon 808 nm irradiation, the uptake ability of tumor cells to Bi NSs@BSA has been improved. Moreover, Bi NSs@BSA also can be used as a good contrast agent for CT imaging and then to observe the distribution of materials in the tumor site. Finally, Bi NSs@BSA-mediated PTT results show a high ablation rate of A549 tumor cells both in vitro and in vivo. All results reveal that Bi NSs@BSA is a promising nanotherapeutic platform for PTT.

Engineered Red Blood Cell Membrane-Coating Salidroside/Indocyanine Green Nanovesicles for High-Efficiency Hypoxic Targeting Phototherapy of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) presents special biological behavior and clinicopathological characteristics and leads to a worse prognosis than other types of breast cancer. The development of an effective therapeutic method is significant to improve the survival rate of TNBC cancer patients. In this work, an engineered red blood cell membrane (RBCm)-coating salidroside/indocyanine green nanovesicle (ARISP) is successfully prepared for hypoxic targeting phototherapy of TNBC. Salidroside in ARISP effectively ameliorates hypoxia-induced tumorigenesis by downregulating the expression of hypoxia-inducible factor 1α (HIF-1α), which increases the killing effect of reactive oxygen species on tumor cells during photodynamic therapy (PDT) using the photosensitizer indocyanine green. Besides, ARISP has an anti-LDLR modified RBCm-coating that extends its circulation time in the blood and escapes from immune surveillance and enhances hypoxia-targeted cellular uptake via the overexpressed LDLR receptor in hypoxic tumor sites. Moreover, guided by near-infrared fluorescence imaging and photoacoustic imaging, ARISP can eliminate tumors via high-efficiency phototherapy and inhibit lung and liver metastasis in TNBC models. Cytotoxicity assay of ARISP indicates the excellent biocompatibility with normal cells and tissues. This study provides fulfilling insights into the anticancer mechanism of reducing HIF-1α for enhanced PDT and has a promising therapeutic potential for TNBC treatment.

Gold Nanostar@Polyaniline Theranostic Agent with High Photothermal Conversion Efficiency for Photoacoustic Imaging-Guided Anticancer Phototherapy at a Low Dosage

Due to the strong and tunable photothermal effect, metallic nanoparticles are of enormous interest in light-activated biomedical applications, such as photoacoustic imaging (PAI) and photothermal therapy (PTT). However, the photothermal conversion efficiency (PCE) of existing metallic photothermal agents is still unsatisfactory. Herein, we develop an efficient photothermal theranostic agent based on a gold nanostar@polyaniline core-shell nanocomposite with high PCE for PAI-guided PTT at a low dosage. After optimizing the relative composition of polyaniline (PANI) and gold nanostars (AuNSs), this nanocomposite eventually empowers an outstanding PCE of up to 78.6%, which is much better than AuNSs or PANI alone and most of the existing photothermal theranostic agents. Besides, the nanocomposite can act as a targeted probe for tumors by hyaluronic acid (HA) modification without compromising the photothermal performance. The obtained nanoprobes named AuNSPHs exhibit promising biocompatibility and great performance of PAI-guided PTT to treat triple-negative breast cancer both in vitro and in vivo. More importantly, a single injection of AuNSPHs significantly suppresses tumor growth with a low dosage of Au (0.095 mg/kg), which is attributed to the high PCE of AuNSPHs. Taking advantage of the exhilarating photothermal conversion ability, this theranostic agent can safely potentiate the antitumor therapeutic efficacy of laser-induced ablation and holds great potential for future medical applications.

Nanogap-containing thermo-plasmonic nano-heaters for amplified photo-triggered tumor ablation at low laser power density

Herein, nanogap amplified plasmonic heat-generators are fabricated by decorating Pt nanodots on gold nanospheres (GNSs@Pt@mPEG) by maintaining strategic nano-gaps (1-2 nm) and studied precisely for plasmonic photothermal therapy (PPTT) of colon cancer by passive tumor targeting. The surface modification of GNSs@Pt with poly(ethylene glycol) methyl ether thiol (mPEG) increases their accumulation in tumor cells and hence the GNSs@Pt@mPEG stay at the tumor site for a longer time. The nanogap amplified GNSs@Pt@mPEG (O.D. = 4.0) generated high plasmonic photothermal hyperthermia and utilized a low NIR power density (0.36 W cm^-2) for the elimination of tumor cells in only 150 s of irradiation time and shows excellent colloidal and photo-stability. The predominant distribution of GNSs@Pt@mPEG caused effective tumor cell death and promoted uniform treatment on tumor sites. In vivo studies demonstrated that the GNSs@Pt@mPEG have very low toxicity, high biocompatibility, and thermal stability, stay longer at the tumor site, induce tumor cell death without side effects, and show significantly less uptake in other organs except for the spleen. The significant accumulations and longer stay suggested that they are favorable for tumor passive uptake and the possibility of enhanced PPTT after intravenous administration. The nano-particles were stable up to O.D. 200 and have at least 12 months shelf-life without losing colloidal stability or photothermal efficacy. These findings lay the groundwork for using GNSs@Pt@mPEG as a NIR light-responsive PPTT agent and demonstrated their potential for further use in clinical applications.

The construct of triple responsive nanocomposite and its antibacterial effect

The current serious mismatch between the increasing severity of bacterial infections and antibiotic production capacity urgently requires the emergence of novel antimicrobial materials. In this paper, dopamine methacrylamide (DMA) and N-isopropylacrylamide (NIPAM) were polymerized as the monomers into a block copolymer poly(dopamine methacrylamide-block-N-isopropylacrylamide) (P(DA-NIP)) and then encapsulated with polydopamine-coated magnetic nanoparticle clusters (MNC) to produce an antibacterial nanocomposite (MNC@P(DA-NIP)). This nanocomposite has triple responses respectively to light, heat and magnetism, which endow MNC@P(DA-NIP) with the abilities to kill bacteria effectively and capture/release bacteria conveniently. Under near-infrared (NIR) light irradiation, MNC@P(DA-NIP) could significantly elevate the temperature through photothermal conversion. The increased temperature favored both the capture of bacteria on MNC@P(DA-NIP), and the damage of bacterial cells, causing bacterial death almost completely. While low temperatures could promote the release of dead bacteria from the nanocomposites, might through the recovery of the hydrophilic state of the outlayer PNIPAM. Moreover, thanks to the magnetic responsibility, MNC@P(DA-NIP) could be easily separated from the bacterial cells and perform better biofilm penetration. The results showed that the antibacterial effect of MNC@P(DA-NIP) was 3.5 times higher than that of MNC, and the recycling capacity of MNC@P(DA-NIP) was better than MNC@PDA. What's more, MNC@P(DA-NIP) possessed the excellent anti-biofilm properties under magnetic field (MF) and NIR. The most important features of the triple-responsive nanocomposites are excellent antibacterial effect, good recyclability and easy preparation, which provide the nanocomposites with great potential in eliminating harmful bacterial cells.

Development of copper vacancy defects in a silver-doped CuS nanoplatform for high-efficiency photothermal-chemodynamic synergistic antitumor therapy

The combination of chemodynamic and photothermal materials can not only improve the therapeutic effect of chemodynamic therapy (CDT) by thermal stimulation, but also play a synergistic therapeutic role. Benefitting from the strong near-infrared absorption ability, copper sulfide (CuS) nanomaterials are widely used in photothermal therapy. However, due to the harsh preparation conditions, low photothermal efficiency and poor biocompatibility, further biomedical application is limited. In this work, silver-doped copper sulfide nanoparticles (BSA-Ag:CuS) were synthesized using a biomineralization strategy using bovine serum albumin (BSA) as a template and stabilizer. Silver doping greatly improved the near-infrared absorption and photothermal efficiency of CuS nanoparticles, which can be used for 1064 nm laser-guided photothermal therapy (PTT). Meanwhile, BSA-Ag:CuS nanoparticles had a synergistic therapeutic effect with CDT and thus showed excellent antitumor performance. In vivo and in vitro biological experiments have shown that BSA-Ag:CuS nanoparticles have good stability, low toxicity, good biocompatibility and strong antitumor ability, and are promising as antitumor agents for future clinical cancer treatment.

Diagnostic Radionuclides Labeled on Biomimetic Nanoparticles for Enhanced Follow-Up Photothermal Therapy of Cancer

Imaging-guided local therapy is the most effective strategy to treat primary cancers in patients. However, the local therapeutic effect should be further improved under the premise of absence of induction of additional side effects. It would be meaningful to analyze the potential assistance of nuclear imaging to the follow-up treatments. In this study,cancer-targeted copper sulfide nanoparticles with ^99m Tc labeling (^99m Tc-M-CuS-PEG) are prepared using-cancer cell membranes as a synthesis reactor and applied for the potential single-photon emission computed tomography/photoacoustic imaging-guided and ^99m Tc-amplified photothermal therapy of cancer. Owing to the homologous targeting capability of the cancer cell membrane, M-CuS-PEG selectively accumulates in homologous tumor sites. After labeling with ^99m Tc, M-CuS-PEG with a high near-infrared light absorbance can realize bimodal imaging-guided photothermal therapy of cancer. Furthermore, the labeled ^99m Tc significantly enhances the cell uptake of M-CuS-PEG by inducing G2/M arrest of the cell cycle, further improving the photothermal antitumor effect, which is positively correlated with endocytosis of the photothermal conversion reagent. Therefore, a novel cancer-targeted theranostic nanoplatform is developed and it is revealed that the labeled ^99m Tc can not only guide but also amplify the subsequent therapy of cancer, providing a conceptual strategy for cancer theranostics with a high biosafety.

Applications of Aptamer-Bound Nanomaterials in Cancer Therapy

Cancer is still a major disease that threatens human life. Although traditional cancer treatment methods are widely used, they still have many disadvantages. Aptamers, owing to their small size, low toxicity, good specificity, and excellent biocompatibility, have been widely applied in biomedical areas. Therefore, the combination of nanomaterials with aptamers offers a new method for cancer treatment. First, we briefly introduce the situation of cancer treatment and aptamers. Then, we discuss the application of aptamers in breast cancer treatment, lung cancer treatment, and other cancer treatment methods. Finally, perspectives on challenges and future applications of aptamers in cancer therapy are discussed.

Carambola-like Bi2Te3 superstructures with enhanced photoabsorption for highly efficient photothermal therapy in the second near-infrared biowindow

Photothermal therapy (PTT) stimulated by light in the second near-infrared (NIR-II) biowindow shows great superiorities in the penetration ability of tissue and maximum permissible exposure (MPE). Exploring new photothermal agents with good optical absorbance in the NIR-II region is highly desirable for efficient cancer therapy. Herein, we successfully prepare carambola-like bismuth telluride (Bi₂Te₃) superstructures modified with PEGylated phospholipid (Bi₂Te₃@PEG) for CT imaging-guided PTT in the NIR-II biowindow. Attributing to their superstructures, Bi₂Te₃@PEG exhibited enhanced photoabsorption with higher photothermal conversion efficiency (55.3% for 1064 nm) compared with that of Bi₂Te₃ nanoparticles. Furthermore, the good X-ray attenuation capacity of Bi endows Bi₂Te₃@PEG with an outstanding performance as computed tomography (CT) contrast agents. Bi₂Te₃@PEG superstructures have been confirmed to effectively eliminate tumor in vitro and in vivo with negligible long-term toxicities, offering them great potential to act as theranostic platforms for cancer diagnosis and treatment.

Bioinspired Camellia japonica carbon dots with high near-infrared absorbance for efficient photothermal cancer therapy

Since carbon dots (CDs) exhibit excellent biocompatibility, low cytotoxicity, near-infrared (NIR) absorbance, and superior photostability, many types of CDs are considered as powerful candidates for photothermal therapy (PTT) applications. However, the development of a desirable CD is still difficult due to insufficient photothermal conversion, thus resulting in the use of high laser power densities at a high dose of CDs for the PTT effect. Herein, bioinspired sulfur-doped CDs (S-CDs) with strong NIR absorbance were prepared from Camellia japonica flowers via a facile hydrothermal method for enhancing the photothermal conversion efficiency. The as-prepared S-CDs exhibited various advantages including cost-effective preparation, good water-solubility, high biocompatibility, intense NIR absorption, and excellent photothermal effect with robust photostability. Most importantly, the optimal low dose of S-CDs (45 μg mL^-1) successfully led to efficient PTT performance with a high photothermal conversion efficiency (55.4%) under moderate laser power (808 nm, 1.1 W cm^-2) for safe and effective cancer therapy.

Prospect of cell penetrating peptides in stem cell tracking

Stem cell therapy has shown great efficacy in many diseases. However, the treatment mechanism is still unclear, which is a big obstacle for promoting clinical research. Therefore, it is particularly important to track transplanted stem cells in vivo, find out the distribution and condition of the stem cells, and furthermore reveal the treatment mechanism. Many tracking methods have been developed, including magnetic resonance imaging (MRI), fluorescence imaging, and ultrasound imaging (UI). Among them, MRI and UI techniques have been used in clinical. In stem cell tracking, a major drawback of these technologies is that the imaging signal is not strong enough, mainly due to the low cell penetration efficiency of imaging particles. Cell penetrating peptides (CPPs) have been widely used for cargo delivery due to its high efficacy, good safety properties, and wide delivery of various cargoes. However, there are few reports on the application of CPPs in current stem cell tracking methods. In this review, we systematically introduced the mechanism of CPPs into cell membranes and their advantages in stem cell tracking, discussed the clinical applications and limitations of CPPs, and finally we summarized several commonly used CPPs and their specific applications in stem cell tracking. Although it is not an innovation of tracer materials, CPPs as a powerful tool have broad prospects in stem cell tracking.

Progress in tumour-targeted drug delivery based on cell-penetrating peptides

Since the discovery of cell-penetrating peptides (CPP) in the 1980s, they have played a unique role in various fields owing to their excellent and unique cell membrane penetration function. In particular, in the treatment of tumours, CPPS have been used to deliver several types of 'cargos' to cancer cells. To address the insufficient targeting ability, non-selectivity, and blood instability, activatable cell-penetrating peptides, which can achieve targeted drug delivery in tumour treatment, enhance curative effects, and reduce toxicity have been developed. This study reviews the application of different cell-penetrating peptides in tumour-targeted delivery, overcoming multidrug resistance, organelle targeting, tumour imaging, and diagnosis, and summarises the different mechanisms of activatable cell-penetrating peptides in detail.